title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Are there any materials that are actually far more fit for a purpose or component that we use frequently, but are either poisonous, hazardous, or detrimental to our health?"
] | [
false
] | null | [
"Is there a more classic example than ",
"Asbestos",
"?"
] | [
"came to say the same thing. suspect OP is trying to get someone to write a homework essay for him"
] | [
"Lead is great in solder and BeO is great for heat dissipation in electronic circuits but their use is diminishing. "
] |
[
"Would a super chimney be an effective means to reduce global warming and generate huge amounts of electricity?"
] | [
false
] | [deleted] | [
"These structures are more commonly called solar updraft towers:",
"http://en.wikipedia.org/wiki/Solar_updraft_tower",
"But the website you link is not well grounded in reality. Bluntly: the size of the structures it discusses are beyond current human construction capability; asserting that it would be simple (... | [
"From a quick browse through the proposed plans on that website, I can tell you that Mike hasn't thought through the system for feeding in air at the base of the chimney. Using extended ducting to get the required air in is much less efficient than not using ducting at all. There will be many sources of friction wh... | [
"330,000 MW is ludicrous, the two fission reactors in a Nimitz class aircraft carrier are able to produce 550MWth which ends up being about 190ish MW at the shafts after being turned into steam. ",
"wiki source",
"A nuclear power plant doesn't make anywhere near that much energy.",
"I think if these towers ha... |
[
"Why is habituation and homeostasis an almost universal aspect of biological systems? Is there an overarching physical property that leads to this?"
] | [
false
] | null | [
"Every living thing we know of beyond a certain complexity is, at it's core, something that maintains its internal order by using energy. Its a thermodynamic system like all others. If life didn't homeostatically regulate itself then it wouldn't exist. Viruses for the most part do not regulate their environment... ... | [
"Homeostasis is one of the defining qualities of what we call \"life.\" If you had something that had all the other qualities of life but did not self-regulate, I don't think we would recognize it as being alive. ",
"Consider fire. In some ways it's kind of like a living thing: it consumes fuel, it outputs waste,... | [
"There's no physical property that perfectly fits the bill (entropy is the closest match but even then you need to make some stretches). So let's do a logical proof and assume the opposite conclusion. Say instead we have an organism with no mechanism regulating homeostasis. What you end up with is an organism that ... |
[
"[META] A legal response to \"Medical Advice on AskScience: The Guidelines\""
] | [
false
] | null | [
"Thanks for the opinion. I'm not an affected party, but I can't let this slip by without comment:",
"Simply saying \"This is not medical advice, but...\" when responding to a medical question IS ABSOLUTELY medical advice",
"That said, I am simply offering an overview of applicable law, and am not suggesting th... | [
"Legal advice has a slightly different standard - it's a two-way thing where a lawyer has to take on a client. Furthermore, legal advice is easier to qualify as not being legal advice semantically than medical advice is. In this case, someone would have to suffer damages from what I wrote here that would not have b... | [
"Good post; but one of the rules here is only scientific posts, with only infrequent metas originating from mods. That said this is a good writeup and the mods are trying to think of someway to use this (maybe a future meta post; or include in the wiki FAQ which should be upgraded soon) -- with attribution of cour... |
[
"DNA-analysis says \"twice as many women as men passed their genes to the next generation\". What is the reason for this?"
] | [
false
] | First of all, ? Some genetic researchers at the University of Arizona in Tucson studied human DNA and found several things. What is interesting, is this: Men and women differed in their participation in reproduction, the researchers report. More men than women get squeezed out of the mating game. As a result, twice as many women as men passed their genes to the next generation. "It is a pattern that's built up over time. The norm through human evolution is for more women to have children than men," said Jason Wilder, a postdoctoral fellow in UA's Arizona Research Laboratories and lead author on the research articles. "There are men around who aren't able to have children, because they are being outcompeted by more successful males." Is this correct? Humans are kinda monogamous so what is the reason for this? | [
"Couple of thoughts:",
"Humans may not be as historically monogamous as they are now. There's an interesting article in the last couple of years, I think in National Geographic, of the hunter-gatherer groups that still exist around the Rift Valley and it mentions that their relationships are pretty open, with par... | [
"You're just getting downvoted, which isn't very helpful. The article isn't doubting that both men and women pass on genes to the next generation, that's a fact. Rather, it's saying that when it comes to selection of mates for procreation, it looks like that a smaller number of men are represented. Think of it th... | [
"Slate, Life's Little Mysteries, CNN, YouTube and Softpedia are not acceptable sources."
] |
[
"If scientists found an undiscovered ancient animal with severe deformities, how would they be able to tell that a feature is a deformity or a naturally occurring attribute?"
] | [
false
] | null | [
"I can't tell you for all deformities, but I can tell you about most deformities.",
"Virtually all life is symmetrical in some way. From simple cells, to the wonderful fractal maths of the way plants lay out leaves, petals etc. All chordate animals are bilaterally symmetrical. If you find an animal where one leg ... | [
"It's a bizarre question for a very simple reason. If it was previously undiscovered, there would be no baseline or comparison to make. Therefore, judgment of a body feature as being deformed is impossible. How could you know?"
] | [
"Thank you very much for the response. Very educated"
] |
[
"Since E=mc^2, does a photon create a gravitational field ?"
] | [
false
] | null | [
"In theory yes, but it's more complicated than just E=mc",
" .",
"One implication of this that was calculated, is if you have a ring of lasers reflecting off mirrors, with a spherical bead in the middle, the gravitational influence of the lasers will very slowly cause the bead to rotate. ",
"Paper here",
"S... | [
"Gravity is what happens when spacetime is ",
". Because spacetime is curved, objects travelling through spacetime move on curved paths. These curved spacetime paths look precisely like moving under the influence of gravity.",
"Photons are affected by gravity because they live in spacetime. ",
" lives in spac... | [
"No, according to special relativity the speed of light is c in any reference frame."
] |
[
"Why is beryllium good at detecting radioactivity?"
] | [
false
] | null | [
"Detectors themselves aren't generally made of beryllium, but light elements like beryllium can be used to moderate neutrons. It's not usually a first choice; you can just use liquid water or plastic, and beryllium is a fairly hazardous material to work with.",
"Without additional context, I can't really say why ... | [
"In what context? What kind of radiation, and what kind of detector?"
] | [
"I'm not sure, I was watching the new Mission: Impossible movie and they used a beryllium rod close to the balls of plutonium to detect something. "
] |
[
"How much electricity could I generate with a bicycle?"
] | [
false
] | We've all seen stationary bicycles retrofitted to turn a car alternator, but what if a person were to build a purpose built generator bike? I'm thinking something along the lines of this modified to replace the rear "wheel" of a stationary bicycle and then through a rectifier to get DC. Would it really be possible to generate 1000 watts of power on your morning workout? | [
"As a cyclist who trains with a power meter, I can answer this question pretty thoroughly...",
"1000 Watts is a sprint effort. Nobody (even pro cyclists) can do that for more than a minute or so. I know a pro cyclist who went several months without ever going above a thousand watts, even for one second (he's a ... | [
"From ",
"wikipedia",
" a bicyclist can reasonably produce about 3-5 Watts/ kg for an hour at a time. Assuming you're about 70 kg, and your equipment was efficient, you might produce 300W*h in a workout- pretty close to what you were looking for. Assuming a price of electricity of 10 cents/kW-hour, you might ... | [
"As a casual gym visitor sustaining 100w for an hour is pretty damn hard work!"
] |
[
"What exactly about antibiotics causes them to interfere with birth control pills?"
] | [
false
] | null | [
"The most accepted theory for this unfortunate effect is that broad spectrum antibiotics reduce levels of intestinal bacteria, which metabolize estrogen components of the contraceptive pill to allow the liposoluble part back into circulation in the body. When bacterial levels are reduced, there is a significant in... | [
"A quick google turned up ",
"this article",
" which gives a fairly simple description of what's going on. To put it in context, hormonal birth control works by regulating the amount of estrogen and progestogen in the body, or in some cases only progestogen. When there's a lot of estrogen and progestogen around... | [
"The only antibiotic that's ever been shown to have any kind of effect on the birth control pill and other kinds of hormonal based antibiotics - and by that I mean an effect on the action of the compounds responsible for preventing pregnancy - is Rifampin.",
"Other antibiotics can make you feel queasy and cause v... |
[
"AskScience AMA Series: I'm the Director of the Addiction Institute at Mount Sinai who studies the neurobiological effects of cannabis and opioids. AMA!"
] | [
false
] | Hi Reddit! I'm Dr. Yasmin Hurd, the Director of the Addiction Institute within the Mount Sinai Behavioral Health System, and the Ward Coleman Chair of Translational Neuroscience and Professor of Psychiatry and Neuroscience at the Icahn School of Medicine at Mount Sinai in New York. I'm an internationally renowned neuroscientist whose translational research examines the neurobiology of drug abuse and related psychiatric disorders. My research exploring the neurobiological effects of cannabis and heroin has significantly shaped the field. Using multidisciplinary research approaches, my research has provided unique insights into the impact of developmental cannabis exposure and epigenetic mechanisms underlying the drug's protracted effects into adulthood and even across generations. My basic science research is complemented by clinical laboratory investigations evaluating the therapeutic potential of novel science-based strategies for the treatment of opioid addiction and related psychiatric disorders. Based on these high-impact accomplishments and my advocacy of drug addiction education and health, I was inducted into the National Academy of Medicine, complementing other honors I have received in the field. Recently, I was featured in the NOVA PBS film " ," which premiered in September and explores the little-known risks and benefits of cannabis use. I'll be on at 3 p.m. (ET, 20 UT), ask me anything! | [
"In your study what is considered smoking too much cannabis? And what are the negative effects of a daily smoker"
] | [
"Hey, 3 in 1:\nWhat can you tell us about the interaction between Marijuana and ",
"A)depression",
"B)anxiety",
"C)attention disorders\n?",
"thanks for playin!"
] | [
"We don’t really classify cannabis in regard to \"too much\" use. We normally operationalize cannabis use in regard to frequency such as multiple times a day, daily, weekly, monthly or as cannabis use disorder in regard to mild, moderate and severe use depending on the negative symptoms it presents for that person.... |
[
"What prevents fruits from rotting before they ripe?"
] | [
false
] | null | [
"First \"ripe\" simply means being ready to eat.",
"\nThis isn't a natural or objective measurement. It's entirely dependent on how humans generally like to eat an object. ",
"If we look at items like berrys, apples, oranges, and other common fruits they are attached to the plant and are \"alive\", being fed b... | [
"The cells in the fruit can continue to replicate and renew the fruit while new energy is being pumped in. At some point, the host organism stops investing energy in keeping them alive -- causing them to drop and decompose or decompose while still connected.",
"And it's not a bright line difference. An unripe a... | [
"Similar to other organisms, plants also have hormones. Completely different structure, even some gases are hormones for them, but comparable functions.",
"External factors and some from the \"mother\" plant and mostly the seed inside the fruit influence the concentration and type of these hormones. The hormones ... |
[
"What is that \"drop\" you feel in your stomach when you receive bad news?"
] | [
false
] | null | [
"Glad to see others have heard of the second brain. If you tie this together with \"Start With Why\" (on mobile, sorry no link) by Simon Sinek (Ted talk available) it can be quite interesting. Essentially, the oldest part of our brain, or animal brain, which is responsible for the majority emotions and decision mak... | [
"Glad to see others have heard of the second brain. If you tie this together with \"Start With Why\" (on mobile, sorry no link) by Simon Sinek (Ted talk available) it can be quite interesting. Essentially, the oldest part of our brain, or animal brain, which is responsible for the majority emotions and decision mak... | [
"What about the one you feel when you drop on a roller coaster or go down a ramp in a car or on a bike?"
] |
[
"Since there are gaseous planets, can there be gaseous moons?"
] | [
false
] | null | [
"The issue is that small bodies don't have the gravity to permanently trap gas around them. Unless the body is at least a certain size, IE very large, you'll get a rocky body instead of a gas giant. At which point is it really a moon or is it a binary planetary system?"
] | [
"It should be noted that gas giants aren't gas the whole way through, or even most of the way through: the pressure is such that most of the matter is no long gaseous, but liquid or even solid (though at the densities and pressures estimated for the cores of those planets, the common definitions for phases of matte... | [
"What is the distinction between a moon and a binary planet? Do planet-moon systems have barycenters inside the planet?"
] |
[
"Even if it's immeasurable by current technology, does turning on my porch light brighten the entire world by some infinitesimal degree?"
] | [
false
] | null | [
"Let's say you turn on a 60 Watt bulb with a 5% conversion to 550 nm (green) photons. This is roughly 8x10",
" photons per second. If we ignore absorption, and distribute them uniformly throughout the atmosphere (within 100 km of the earth's surface), that leaves roughly 1 photon per 10 m",
" of air per secon... | [
"What does \"brighten the entire world\" mean? Are you asking if you turn on a lamp in Berlin does it brighten a room in Wellington? No."
] | [
"No, I understand that enclosed spaces are likely to not be illuminated due to their power to impede the passage of photons. Because light emanates in all directions from a fixed point, though, one would presume that any and all light that originates outside would go on to illuminate every other external surface. I... |
[
"What is stopping us from growing stem cells?"
] | [
false
] | In a lab, the same way we grow regular, fully differentiated cells, from practically any other part of the body? Are stem cells like the Pokemon Eve, and can evolve (differentiate) into a set which doesn't contain another stem cell? | [
"Stem cells are finicky, for one. Also, there are adult stem cells and embryonic stem cells. Adult stem cells are not as robust as embryonic stem cells. However, embryonic stem cells can only be harvested from human embryos in a process that destroys the embryos so there are major ethical considerations. The U.S. c... | [
"We don't grow regular, fully differentiated cells in the lab. In the lab, we either grow some sort of cancer cell, some sort of immortalized cell line that was ",
" normal, or some sort of stem cell line.",
"I'm being generous here about the definition of stem cell, so this isn't specific to embryonic or adult... | [
"If people are growing skin in lab, it is likely that they are using skin stem cells, which are needed to replenish a cell population with a lot of turnover. ",
"Cells in multicellular organisms have evolved to closely monitor signals from other cells within the body to understand what they should and should not ... |
[
"Do we know in what direction we'd need to accelerate towards, such that we'd lose all the moment we have gained from the motion of the cosmos?"
] | [
false
] | null | [
" Yes. Go 380 km/s towards the constellation Leo.",
" The cosmic microwave dipole has a rest frame. We can tell because we see a ",
"dipole moment in the CMB.",
" This just means that we see the CMB a litter warmer in one direction, and colder in the other. This means we're moving (relative the CMB rest frame... | [
"We're traveling at whatever speed up to the speed of light that you want. No reference frame is more valid than the next. "
] | [
"There is a frame of reference that provides us a speed relative to the cosmic background radiation. Some people use this as a \"default\" reference frame and you can cite our speed based on that frame of reference.",
"You're right that it's not particularly more valid than any other, as far as physics equations... |
[
"What happens in the brain when a deaf (from birth) person reads?"
] | [
false
] | I was thinking about how when I read silently to myself, I "hear" the words I'm reading in my head. When I read the word "window" I "hear" it, know what it is, and continue on. I don't "see" in my mind's eye a picture of a window unless I need to (e.g. to solve a puzzle I might picture various kinds of windows). Then I wondered, for someone who has never heard the the pronunciation of the word or know what it sounds like, what happens when they read the word "window"? Do they picture it in their mind's eye or does something else entirely different take place? | [
"I'd like to add a follow up question.",
"I recall hearing that deaf schizophrenics experience sign hallucinations rather than voices in their heads. Would this be in the same relative area as to what would be happening here with deaf people reading?"
] | [
"I am half deaf, and while it means little in this situation, I have thought this idea for as long as I had hypothesised it myself;\nHumans as a species are drawn to symbols and imagery - rock paintings, car insignia, flag emblems, you name it.\nYou don't need to speak to be able to learn. You need to understand ho... | [
"We do it all the time, like when you are out on the street, you don't keep telling to yourself \"car, bus, yellow, dog\", etc, you just look at those things and know what they are, same thing with words, if you see the word \"dog\", you don't have to read it to your brain like it's a 5 year old, once you see the w... |
[
"What happens in our bodies when we die via blood loss?"
] | [
false
] | and more specifically, why does losing too much blood cause us to die? do our hearts shut down? do our lungs stop working? it's always confused and perplexed me. | [
"Short version: the bottom line is that your blood contains nutrients needed by your organs to keep you alive. Losing blood means you lose nutrients and oxygens necessary for viability.",
"Longer version (at physiological level):\n1) Losing approximately 10% of our blood volume will cause increase of heart rate, ... | [
"There is a limit to how much blood pressure your heart and blood vessels can generate. If the volume of your blood gets too low, you cannot pump enough blood and therefore oxygen to your brain, so it stops working and you die."
] | [
"But still valid nonetheless - Some of the methods were as simple as picking up the severed head immediately following and talking to it, to see if they could elicit a response from a still conscious person."
] |
[
"Scientists is this feasible?"
] | [
false
] | null | [
"Depending on how you set up your variables and frame of reference, technically speaking the universe could be described that way mathematically.",
"Edit: ",
"The Coriolis Effect"
] | [
"Going to take a look at this later can't on my phone"
] | [
"All motion is relative, so I don't think it can be said to be impossible. In fact, it is definitely true if you simply pick the correct frame of reference. So you can ",
" the motion of the universe this way. But it you can't really come up with a way to ",
" the motion of the universe this way. ",
"Choosin... |
[
"Is economics a science ? Is there a simple, systematic way to understand economics ?"
] | [
false
] | I've always been skeptical about the fact that economics is a science, mainly because I can't quite grasp it. Please hold on, and change my mind (and probably others' too). One thing that comes to my mind is that there is no Nobel prize in economics (actually there is, but it's not given out by the Nobel academy so it is different from the other nobel prizes indeed). Also,[This link]( ) says that the 2008 crisis is partly due to the fact that the Black-Scholes equation was wrongly used. It therefore makes me believe that economists back then did not really understand their models, at least when the economy itself had substantially changed in a very short period of time. Another interesting point is that economics is hard to grasp, maybe because it relies on a lot of technical stuff implemented in the real world. I used to learn physics through simple models, where you could study the influence of the hypothesis of a model on the outcome of that very model. That is a very efficient way to learn "hard" science and I wondered if it is possible to learn economics that way. In any case, how did you learn it ? I'm deeply worried for the robustness of our understanding of economics, on the one hand from economists themselves (is it a science?) and on the other hand from the major part of a country's population. Especially in these times, keeping key thematics unreachable for the bulk of the population, such as world/country economics, is a threat to doing the right choices as a citizen. That is why I'm asking here and hopefully not insulting anyone with these questions. | [
"Science isn't a thing in and of itself. Science measures and describes things. So, sure, every time you push a bowling ball off a table, it will fall. That's physics. However, if you repeatedly push a cat off that same table, what will happen? Will it fall? Jump? Scratch the heck out of you? See, that's biology, w... | [
"This is an interesting question and for some an offensive one :)",
"There is a quite common agreement in philosophy of science that anything that is a science must either be an empirical science or a formal science.",
"Empirical sciences are descriptions of fact (the universe). physics is the front runner exam... | [
"I wanna point out that the example with the cat above is much better described as ",
"ethology",
", while the word ",
"biology",
" is usually taken to mean the study of e.g. cells, evolution, genetics, and the physiology of organisms. No doubt the two are related, and ethology can easily be considered part... |
[
"When some species lose a limb, the limb continues to move. When others lose limbs they go limp immediately... what's causing one to move but not the other?"
] | [
false
] | This question brought to you by weed and | [
"This is a good answer, but the effect can also vary on the way the host organism's nervous system is organised. For example, most limbs of most organisms will twitch in response to salt water due to the ions, but octopus arms actually retain some functionality after having been severed. I remember reading one pape... | [
"This is likely dependent on nerve stimulation. Possibly how the nerves are severed, what nerves in particular exist on the appendage, and how damaged they are.",
"The salt water in the starfish's environment may also play a part in it. Take ",
"this other example",
" of a dead squid moving after soy sauce is... | [
"Cool! Do you have links to vids?"
] |
[
"How much do aerodynamics matter in relation to a vehicle's MPG?"
] | [
false
] | A friend of mine used to work at a major car company. He told me that he learned (second-hand) that vehicular aerodynamics don't have much of an effect on modern vehicles at normal (<100mph speeds). So do they actually have a noticeable effect? For example, my truck weighs ~4400lbs and has about 260 bhp with 280 ft-lbs torque. I average about 18mpg. Would I get any noticeable increase if I were in a corvette or ferrari of identical weight, with all other factors being equal? Edit: To be more clear, I think it's obvious to most that a more aerodynamic vehicle will have a positive effect on gas mileage, I'm just unclear as to whether that effect is noticeable in the real world. | [
"Although not directly answering your question, Mythbusters did an amusing episode where they covered a ",
"car in clay",
" and put a bunch of dimples in it like a golf ball. They ended up with about a +10% boost in MPG due to less drag going well less than 100MPH.",
"Here's a short video of it",
"."
] | [
"This should be interesting for you:\n",
"http://gcep.stanford.edu/pdfs/ChEHeXOTnf3dHH5qjYRXMA/10_Browand_10_11_trans.pdf",
"On the side, the equation for drag has (amongst other things) 3 parameters that really matter. There's the speed at which you are traveling through the medium, the drag coefficient of the... | [
"If there were no friction, you would only need to use energy to accelerate up to speed. Just like you were in space-- you'd keep right on going at 55mph if you took your foot off the gas when you reached it.",
"This obviously does not happen-- friction is slowing the car down, and so some power is required to k... |
[
"What types of evidence go into diagnosing mitochondrial diseases?"
] | [
false
] | Given Justina Pelletier's case, I was curious whether mitochondrial diseases are difficult to diagnose. Are muscle biopsy, biochemical tests, and genetic tests a gold standard? What other factors must/might one consider? I am NOT seeking medical advice! Rather, I am curious about what types of evidence might a doctor consider that would lead to a diagnosis of mitochondrial disease. | [
"That depends on the disease - I'm not a clinician, but have been working with DNA sequencing for a long time.",
"The genome of the mitochondria is incredibly small compared to the rest of the cell, and there are usually plenty of mitochondria per cell, which makes it easy to harvest a lot of it from a small amou... | [
"You are probably right. I may have had the same visceral reaction to the parents as the Children's Hospital doc. Dad strikes me a narcissistic Personality and mom as borderline. Even if true, that doesn't mean the child isn't sick. The truth will eventually come out."
] | [
"Sort of... the problem is that 80% of mitochondrial diseases are mutations in the nuclear genome that encode for mitochondrial proteins. It's a mess-- typically they'll run mtDNA first to rule that out, but then do nuclear sequencing of the 1500 genes that they know affect mitochondrial function (although there ar... |
[
"What is the \"holy grail\" of your field, what is needed to obtain it, and how will this impact the world?"
] | [
false
] | [deleted] | [
"An unambiguous and universally-applicable site index for tree quality. In Urban Forestry, the national standard for trees (ANSI) specifically does not ensure quality, and only serves to standardize tree nursery practices. The vast difference between planting sites and tree quality results in huge monetary losses i... | [
"I plan on doing high energy physics so i'll answer for that:",
"The 'holy grail' for high energy physics I think is the Theory of Everything. A unification of the four fundamental interactions - gravity, electromagnetism, the weak force, and the strong force - at extremely high energies (the type of energies tha... | [
"Computer graphics: The holy grail was used to be creating photorealistic images and videos. Graphics researchers succeeded, but realized that the solution has a significant disadvantage -- the requirement for hundreds of thousands of expert man hours. So the new holy grail is to make the creation and manipulation ... |
[
"Do all steroid hormones increase blood glucose and cause diabetes?"
] | [
false
] | We all know that a chronically high cortisol can lead to diabetes due to cortisol increasing glucose levels. Is this also true for adrenal androgen steroids like DHEA(S) and androstenedione? | [
"No, androgen receptor activation seems to improve glucose metabolism through a few pathways from what I remember. B-cell activation as well as increased GLUT1 expression and well the increase in the skeletal muscle ability to store glycogen. ",
"There are many negative effects to chronically elevated androgens, ... | [
"That was essentially the premise behind the development of SARMs (selective androgen receptor modulators) but in trials they never quite panned out, and negative effects were still apparent (dyslipidemia, hypercholesterolemia, elevated liver enzymes, suppression of the hypothalamic-pituitary axis, etc...) So right... | [
"Steroid induced diabetes is ICD10 code E09.9. You treat like you treat type 2 diabetes primarily; they need more prandial insulin than basal so the dosages are a little different. You can get glucoses of 400s on steroids. Diabetes is diagnosed with fasting glucose > 126 x 2."
] |
[
"Is it possible to make a vaccine for any virus?"
] | [
false
] | Wouldn't it be possible to encounter a virus for which we can't get the vaccine or it is too complex to be achieved in a reasonable time? | [
"Consider that a virus proliferates by integrating its gene in a cell of the host. A necessary step for that is the binding of the virus to an extracellular receptor. In other words, the virus must at some point in its self-replication cycle bind to a native protein.",
"In other words, a virus contains at least o... | [
"A+ reading man :)",
"You touch upon it, and I just wanted to add an underlining, that the time perspective is the important factor as to whether we can make a vaccine. ",
"Medicine is a constant evolving field, and as such what seems insurmountable by today’s technology might be nothing but a common cold a sho... | [
"Yes, it is surely possible but it makes much much time, efforts, hard work, research and money. Humans have been making vaccines for different viruses since 1000 thousands of years. So, in order to make our future generation and the current generation healthy and to make them safe from every virus we need to make ... |
[
"Is there an actual exchange of photon particles (electromagnetic force carriers) between two magnets? And if so, do these photons have a specific wavelength?"
] | [
false
] | And in a related question, is there a theoretical mesh size for a Faraday cage where it would stop a compass from pointing to the earth's magnetic pole? | [
"No, magnets don't emit photons. Quantum electrodynamics uses an approximation involving 'virtual photons', but this is just an abstraction to help understand the underlying theory. ",
"The equivalent to Faraday cage would be something like a magnetic shield built of some material like ",
"Mu metal",
". Th... | [
"Faraday cages are only effective versus time-varying fields. With these, the size of the mesh determines what frequency range the cage is effective at shielding. ",
"As ",
"/u/just_commenting",
" mentioned, there is shielding for magnetic fields with consists of either a high magnetic permeability material o... | [
"It's best not to view virtual photons as actual particles at all. Virtual photons are not proper perturbations in the field like normal photons, but are more like incoherent vibrations."
] |
[
"Why are the pores on the face so much larger than anywhere else on the body?"
] | [
false
] | Reposted at the request if | [
"Age is a factor in the pore size, as when you age the skin on your body starts to lose its elasticity, causing it to stretch and the pores to enlarge. Sun damage can also thicken skin, which can cause larger pores. Prolonged sun exposure over time can also sap collagen, elastin and water from your skin, which caus... | [
"I don't see what age has to do with it since your whole body is the same age. Are you saying that the larger pore size is just because we don't cover up our face as much as the rest of our body?"
] | [
"There's also an oil production component to it. The more oil that an area of skin produces, the more pools in the pores, stretching them out (hence the difference in pore size between, say, your nose and your arm). As the skin gets older, it doesn't bounce back as easily (lack of elastin) and the pores are permane... |
[
"Why is it that digital storage sizes are powers of 8?"
] | [
false
] | I was looking through a variety of hard drives and USB memory sticks, I have curiously asked this my self for a while, but if anyone knows, please could you tell me why, is it because the way NTFS and FAT32 work? Or is there a longer story than that? Thank you for looking :-) | [
"I don't think NTFS nor FAT32 use that much space, Just let's do the math.",
"What they are selling you is one terabyte. ",
"The term Tera- impies that it's expressed in decimal and not in binary",
" so 1 Terabyte by definition has 1000",
" bytes (NOTE that it's not 1024) so what they are promissing is 1 00... | [
"Powers of 8? Do you mean powers of 2? It's possible you're thinking of the number 8 in terms of the common acceptance of there being 8 bits in 1 byte, but the sizes of digital information storage tiers are commonly prefixed according to a base 2 definition.",
"(2",
" = 1024 bytes = 1 kilobyte",
"(2",
" = 1... | [
"You lose ",
" space to that, but it's not nearly as significant as the 2",
" vs 10",
" conversion. With all the compounding of that 1000 vs 1024 error on the way up to terabyte scale, you end up with a situation where \"1 TB\" to a hard drive manufacturer is only \"931 GB\" for software."
] |
[
"Where do we draw the line between species?"
] | [
false
] | What's the difference between you and me? I know that we are very similar genetically, but at some point there has to be a blurry line, right? At what point do we decide "ok, that's a new species", instead of "that's the same species with the typical genetic differences"? Edit: Cool, thanks for the replies! | [
"We live without a strong definition. The definition is SUPPOSED to be that those within the same species can produce fertile offspring (the mating of a male donkey and a female horse (a mule) almost never produces a fertile offspring - there have been fertile females, but no fertile males) ",
"this is generall... | [
"overall excellent answer, but I'd dispute that ring species are an issue. You seem to be making the common mistake of thinking of animals in terms of individuals rather than populations. In a ring species, even if certain individuals may not be fertile with other individuals, the population as a whole is still a s... | [
"Afaik it's when two different organisms can no longer procreate. For instance, when one group of a certain species is isolated from the rest, the small group tends to have a faster genetic drift (punctuated equilibrium is the concept that smaller groups change DNA faster).",
"At one point, the DNA becomes differ... |
[
"Is it possible to calibrate an optical instrument using the cosmic background radiation as a source?"
] | [
false
] | [deleted] | [
"The cosmic microwave background is in the microwave range, how would that help for optical instruments?"
] | [
"A more polite answer would be",
"No. Because the CMBR is in the microwave range and optical instruments mostly work in the visible light range."
] | [
"I was wondering about that as I wrote My answer. But my point wasn’t to answer the question but to example a better way to phrase the OC’s answer. So I let it go.",
"But thank you for the info! I’ve never really considered microwave focusable through a lens."
] |
[
"Stemming from a TIL post (\"TIL the human womb is the oxygen equivalent of the top of Mt Everest, designed to keep the fetus asleep 95% of the time\"), what is the true oxygenation level in the womb and what percentage of the time are fetuses asleep?"
] | [
false
] | was posted on TIL, and basically the comments didn't really provide a clear explanation of their reasoning behind their title. Is the oxygenation of blood from the placenta truly equal to "the top of Mt Everest" and what percentage of the time are fetuses asleep in the womb? Are these directly related or independent of one another? | [
"That's actually not a bad comparison, sort of. There is about half as much oxygen at the top of Mount Everest as there is at sea level, in terms of partial pressure. There is about half as much oxygen in fetal blood as there is in adult blood. So on that point, it's about right.",
"Fetal blood is not the same as... | [
"Stem cell quiescence and differentiation is greatly altered in conditions of hypoxia. Could be related to that."
] | [
"They also have adapted erythropoietin secretion and oxygen sensing mechanisms."
] |
[
"Would a helium filled balloon rise faster than a regular air filled balloon when placed under water?"
] | [
false
] | [deleted] | [
"Yes, but insignificantly so. The difference between the density of helium and that of water is insignificantly larger than the difference between the density of air and that of water."
] | [
" since I was curious, I calculated the speed at which the drag forces would equal the buoyant forces for both a helium balloon in air and an air balloon in water. At a speed of 5.51m/s, the drag force will equal the buoyant force for the helium balloon in air, and at a speed at 5.87m/s the drag force will equal t... | [
"You need to account for drag, too, which will be the great equalizer here."
] |
[
"number of protons in the universe"
] | [
false
] | I've often seen it said on the internet that there are 10 protons in the universe. How was this number derived and is it meaningful ? | [
"1) We know how much mass a proton has.",
"2) We know that the sun comprises 99.86% of the mass of our solar system. So we assume that the mass of the universe is overwhelmingly dominated by stellar objects. (We may add a bit of mass to account for nebulas, etc.)",
"3) Based on our observations, we can estima... | [
"Nice explanation, you might want to stress the \"observable\" part, though."
] | [
"the observable universe is an unknown fraction of the universe though right ?"
] |
[
"Why do we get headaches when we look at screens too long?"
] | [
false
] | null | [
"Not just looking at screens, but any kind of eye strain can lead to tension headaches caused by reduced blood circulation in the muscles around the eyes."
] | [
"Then I must ask, how does looking at a screen reduce blood circulation in the muscles around the eye?"
] | [
"Admittedly I'm no expert in anatomy, so maybe someone with a bit more knowledge on the subject could add to this, but essentially when focusing on an object the muscles around the eye tighten and this contraction makes less blood flow through the muscles."
] |
[
"Why have CPUs been limited in frequency to around 3.5Ghz for so many years? What prevents us from increasing the frequency to 10, 100, 1000Ghz?"
] | [
false
] | null | [
"(Disclaimer: Possibly a too-dumbed-down version)",
"http://en.wikipedia.org/wiki/Transistor#Transistor_as_a_switch",
"http://en.wikipedia.org/wiki/Leakage_(electronics)",
"The individual bits in your computer aren't so much 1 and 0 as they are High and Low voltage, with 'on' and 'off' being relative. To rea... | [
"(Disclaimer: Possibly a too-dumbed-down version)",
"http://en.wikipedia.org/wiki/Transistor#Transistor_as_a_switch",
"http://en.wikipedia.org/wiki/Leakage_(electronics)",
"The individual bits in your computer aren't so much 1 and 0 as they are High and Low voltage, with 'on' and 'off' being relative. To rea... | [
"(Disclaimer: Possibly a too-dumbed-down version)",
"http://en.wikipedia.org/wiki/Transistor#Transistor_as_a_switch",
"http://en.wikipedia.org/wiki/Leakage_(electronics)",
"The individual bits in your computer aren't so much 1 and 0 as they are High and Low voltage, with 'on' and 'off' being relative. To rea... |
[
"Why do some metals glow red hot at their melting point (i.e. Iron, nickel, etc) while others (i.e. Aluminum) are silver when molten?"
] | [
false
] | null | [
"Different melting points.",
"\nAt roughly around 700°C (=1292°F) the human eye notices a faint dark red glow.\nAluminum is already molten at this temperature wheras iron needs a lot more heat and is already glowing bright yellow (around 1550°C (=2822°F))"
] | [
"The colour of glowing metal is dominated by ",
"black-body radiation",
", which depends on temperature rather than chemistry. If you continue heating liquid metals you will see the colour change with increasing temperature."
] | [
"Things glow \"red hot\" due to black body radiation, which depends only on temperature. Anything hot enough would glow in the viaible range. ",
"The reason iron glows near his melting point and alominium doesn't is that the melting point of iron is much higher, thus by the time it melts it reached a temperature ... |
[
"Are there alternative treatments to antibiotic resistant infections?"
] | [
false
] | Recently, there have been a slew of articles about bacteria that are now resistant to our antibiotics of last resort. Apparently, will be the first to cross the finish line. Barring the discovery of new more potent antibiotics, what will medicine do to fight these antibiotic resistant infections? | [
"Billions are spent annually funding many avenues of research looking for new drugs. The catch is, as soon as a new drug get through trials and FDA or similar for approval, bacteria have already developed resistance to it. ",
"To keep from being a total storm cloud, the hope is that these new drugs can target dif... | [
"In eastern Europe bacteriophages have been used for a long time to fight infections. Phages are pretty much everywhere and they selectively infect bacteria. You can take a sample of phages and select the right one for your infection. Of course bacteria evolve and can develop resistances against phages as well, but... | [
"My understanding was that, as you said, combination therapy is quite important: ",
"https://en.m.wikipedia.org/wiki/Combination_therapy"
] |
[
"I have a question about magnetism and google didnt give me an answer"
] | [
false
] | I was just wondering what happens if you bend a magnet (like physically bend the damn thing). Say you have a long thin magnet with the field passing through the width instead of the height. If you bend that magnet so that the ends meet, would you have a circle where the entire outside is a single pole? If so, say you have 2 of these things and put them flat on a table, can they repel each other constantly? (if both their outside poles are the same anyway) What if you take a plate like this instead of a stick and fold it into a sphere? Does it act like a magnet with a single pole, the other pole being the inside? It's been on my mind all day and it would be nice of someone knew the answer. It's probably silly but I would like to know anyway | [
"No. Such a thing would be a magnetic monopole, and they don't exist (they might exist in quantum theory, but that is an entirely different thing). As all the field lines have to connect a northpole with a southpole, it is impossible to contain a single magnetic pole inside something.\nIn the case of the ring, the ... | [
"Monopoles don't exist.",
"http://en.wikipedia.org/wiki/Magnetic_monopole#Searches_for_magnetic_monopoles"
] | [
"When you try to bend a modern, realistic magnet it will snap in half, so this scenario uses an imaginary magnet with perfect properties.",
"If the magnet's electrons were all spinning in the same direction, and it was impossible to reverse any of their spins, you'd end up needing an ",
" force in order to bend... |
[
"What would you see if a particularly accident prone astronaut shone a flashlight at you while falling into a black hole?"
] | [
false
] | Say you're somehow static relative to the singularity. I know light can't escape the event horizon so what would be seen by you from the flashlight in the fractions of a second (from your perspective) before it is crossed? | [
"So, you don't actually observe the astronaut crossing the event horizon. What happens, from your frame of reference, is that the astronaut gets more and more time dilated, and moves slower and slower as they approach the event horizon. This means that the light gets dimmer and dimmer, because the time between each... | [
"Lower power over a longer time interval is what happens.",
"The light doesn't have a hard shut off, but there is a stage where you're getting photons far too slowly and with such low energy that it's considerably less than the background."
] | [
"The light doesn't have a hard shut off, but there is a stage where you're getting photons far too slowly and with such low energy that it's considerably less than the background.",
"The intensity drops exponentially. You quickly receive the last photon ever. A bit later you can calculate a 10",
" probability t... |
[
"If a small object is in orbit of a larger object, will the smaller object crash into the large object eventually?"
] | [
false
] | There is no debris of any size in this hypothetical. | [
"If the two are in an isolated orbit with no external perturbations, the orbit will still decay over a very long time due to gravitational radiation."
] | [
"Roche radius",
" all up in here. In the radius- collision. Outside- perfectly fine."
] | [
"That's a completely different issue: inside the Roche radius (which is different depending on the size and composition of the orbiting object) the orbiting object will ",
", not decay in its orbit. "
] |
[
"How do animals become larger? Or rather, what determines their size?"
] | [
false
] | Spurred on by this of a replica whale heart. I don't even know how to word this properly. What determines the equilibrium size of an animal? | [
"Well, that whale heart sure is astonishing. The reason that whales can be so big—larger than any terrestrial animal—is they live in water. The limiting factor to land animal size is gravity. As animals grow in size, their mass grows as the cube ( d",
" ) of their dimensions, while the surface area they use for s... | [
"Another interesting tidbit.. because of the cube/squared law warm-blooded species have a definite maximal-size advantage over other animals. It is much easier to attain and maintain an optimal body temperature for large mammals as they can metabolize heat which radiates from the inside out. Cold blooded animals ar... | [
"Never turn your back on the aquatic mammals."
] |
[
"What (if any) are the hazards of being exposed to perfluorocarbons?"
] | [
false
] | Recently in New York City the MTA is starting an airflow test in the subway. This makes it seem like they are putting millions of people in danger. Is this safe or should I start taking a taxi for the month? | [
"That card looks like it was made by someone other than the MTA for no reason other than to scare you. The amounts of these perfluorocarbon gases released are so small that there are probably far greater concentrations of compounds that are legitimate concerns, like hydrogen sulfide and carbon monoxide, and even t... | [
"Perfluorocarbon tracers",
" are chemically inert and not dangerous at all to inhale, unless you are inhaling so much that it is reducing your oxygen intake. In other words, don't breathe it ",
".",
"The stress experienced by an uninformed person reading that scare flyer would have a far greater health impact... | [
"That card looks pretty false. I'd like to think the state wouldn't straight up expose millions of people to a gas paraphrased by the card to not be fully understood with respect to health effects. ",
"I may only have a bachelor's in chemistry, but ignore this, the taxis are too expensive."
] |
[
"Is it possible to see the constellations that we see from Earth from other parts of the milky way?"
] | [
false
] | [deleted] | [
"Yes, from another nearby solar system (usually), but no, not from the other side of the Milky Way. None of the constellations have stars with similar distances from Earth, so if you start moving around, the apparent alignment of those stars would change slightly from what we see normally. Most of the stars are far... | [
"Constellations are man-made assignments to groups of stars that happen to be somewhat close in the sky from our point of view. You get different constellations just from asking different cultures ",
"."
] | [
"That's interesting, thank you for answering!",
"I wonder what constellations they have on the other side of the galaxy. They as in aliens. We all know we cant be the only ones lol"
] |
[
"What is the Riemann Zeta Function, and what's the point of it?"
] | [
false
] | I've read into this thing via wikipedia and wolfram mathematica, and I still have no idea what it's trying to do. | [
"Let's first describe something that's NOT the Riemann zeta function.",
"Consider these series:",
"2",
" + 2",
" + 2",
" + 2",
" + 2",
" + ... = 2",
"3",
" + 3",
" + 3",
" + ... = 3/2",
"4",
" + 4",
" + 4",
" + ... = 4/3",
"We know these values because they are geometric series. We c... | [
"What are you understanding and not understanding about it and what would you like to know? It's tough to answer your question because it is a bit vague. Also what are your expectations for a \"point\" of a function and what it must try to do? Practical applications? Appearance in nature? "
] | [
"I'm only a physicist and not a mathematician, but wouldn't it be more correct to say that the Riemann hypothesis is actually a problem in complex analysis that happens to have (HUGE) applications to number theory?",
"The zeta function is just some meromorphic function and we want to find its roots.",
"How seri... |
[
"What selection pressures caused gender/sex to evolve?"
] | [
false
] | Since life came from a single celled organsim, what are the selection pressures that could've caused mutations/genes that resulted in genders? Bonus questions I'd much appreciate if you could answer: What selection pressures along with changes in genes caused different developments of sexual reproduction mechanisms? In essence how is it that some species reproduce in a manner that is completely different from a species whom not long ago came from the same ancestor? Are their species where more than two genders/sexes evolved? Thanks in advance. | [
"There's a pop science book that has a good overview of some of the theories related to it called The Red Queen by Matt Ridley.",
"One of the more popular theories is that sex evolved to fight off disease. The longer lived the species, the more likely they are to have sex, because viruses and bacteria have very s... | [
"As to whether there are species with more than two sexes, yes. But they tend to be extremophiles. I believe some slime molds do.",
"Actually many fungi have large numbers of \"mating types\", which are essentially sexes. The number of mating types depends on the species of fungus: some only have two, but some h... | [
"Your response seems to mostly be about sexual reproduction. It seems to me that it could be possible to have a species with sexual reproduction but only one gender - there would have to be some mechanism to prevent self-impregnation."
] |
[
"Why do you salivate so intensely when you're about to vomit?"
] | [
false
] | null | [
"Just to be slightly more specific, from wikipedia:\n\"Increased salivation to protect tooth enamel from stomach acids. (Excessive vomiting leads to dental erosion). This is part of the PNS output.\"",
"http://en.wikipedia.org/wiki/Vomiting#Pathophysiology",
"It's pretty cool to read the ways your body deals wi... | [
"Just to be slightly more specific, from wikipedia:\n\"Increased salivation to protect tooth enamel from stomach acids. (Excessive vomiting leads to dental erosion). This is part of the PNS output.\"",
"http://en.wikipedia.org/wiki/Vomiting#Pathophysiology",
"It's pretty cool to read the ways your body deals wi... | [
"You salivate because emesis (the act of throwing up) is heavily mediated by the parasympathetic nervous system. The PNS serves as your \"rest and digest\" system. Increase in parasympathetic tone will increase gut activity and increase secretions in general.",
"tl;dr Parasympathetic stimulation=increased secret... |
[
"If I'm sitting on the 12th floor of our condo (~120-150 ft), how far out can I see until the ocean disappears over the horizon?"
] | [
false
] | Approximately. According to my brother and Life of Pi (which I haven't validated for myself), you can see ~2 miles to the horizon from sea level. Assuming that's close to accurate, I was wondering just how much that distance increases according to height. Or rather, what the relationship is between height relative to ground (sea level in this case) and the distance to the horizon, taking into account the curvature of the Earth. I imagine there's a decently simple way to to it mathematically, but I've yet to really sit down and work it out. Thanks reddit! | [
"The maths comes out ",
"quite simple",
", it's sqrt(2*R*h), where R is the radius of the Earth (about 6500 km) and h is your height above the surface.",
"Plugging in 150 feet gives you about 24 kilometres, or 15 miles."
] | [
"would it be further if you take refraction into account?"
] | [
"Atmosphere. ",
"seemingly it would be further but over a distance as short as that, probably not by much.\n",
"http://en.wikipedia.org/wiki/Atmospheric_refraction#Terrestrial_refraction"
] |
[
"What would happen if two black holes collided?"
] | [
false
] | What I mean is, what would happen if two black holes collided, like two asteroids colliding. would they both merge and make one black hole as massive as the sum of both of their masses? If one was larger, would the larger one absorb the smaller one? What would happen? | [
"They would merge to form one large black hole. This process would generate a large gravitational wave signal -- gravitational waves, which are predicted by general relativity, have never been directly observed -- as they spin in towards each other and merge. Groups such as LIGO and VIRGO are designed to look for... | [
"This is one of the things projects like LIGO and VIRGO should be able to answer. Gravitational wave detection is very hard, because it requires extremely sensitive measurements. In about 5 years, LIGO, for example, expects to have the sensitivity to address this question meaningfully and to begin doing gravitati... | [
"How often does this occur?"
] |
[
"What are the obstacles for a mission to Europa ?"
] | [
false
] | As far as I know, there is no mission planned to explore Europa and its supposed oceans. Why is that ? Is seems that technologically it's not unfeasible: We know how to send rovers, we have , and while I'm not sure, it doesn't feel super difficult to imagine a robot melting the ice (through radioactivity maybe?) until it reaches the liquid oceans and then send pictures / data of whatever it finds there. But as there is no mission planned or even talked about (not that I've heard of), despite the fact it's regularly quoted as the "most likely place to have life", there must be some severe obstacles. | [
"Sure, but we already have procedure for that, right ? I remember the rover we put on mars was carefully decontaminated."
] | [
"Technologically it's entirely possible to go to Europa. The problem is undoubtedly finding the (political and public) motivation to do so. Cassini and the Huygens probe were launched under a similar premise, explore Saturn and Titan, which was the most likely life supporting planet, with it's thick atmosphere and ... | [
"I might be wrong but I believe there would be practical gain as to know that life can develop in different environments than the terrestrial one.",
"\nAs for the political and public motivation, how is that worse than, say, send a rover to Mars ? (or basically any scientific research that doesn't have any direct... |
[
"How can a constant vary?"
] | [
false
] | I've been doing some reading about varying constants and I can't understand it. I just can't get past the name... it is very oxymoronic. I try to read the articles online and understand the concept but I always get hung up on the principle. It is very counter intuitive. Could someone explain how its possible? If the fine-structure constant varies over time wouldn't it not be a constant? | [
"Something can be a constant over time, or over space, or both.",
"So in this case, the fine structure constant is constant over space, but not over time."
] | [
"For example, Hubble's constant is the reciprocal of the age of the universe."
] | [
"A useful analogy, but let's just for clarification note that Newton's gravitational constant G is a universal constant (6.67E-11 N/(m/kg)"
] |
[
"Can someone explain natural logs to me in a straightforward manner? Maybe using graphs?"
] | [
false
] | I use them for work and grad school all the time, but I really don't fully understand what a natural log of a number is (or a log, obviously). I've read a lot of posts here on but still it hasn't sunk in. | [
"The whole argument is based on the idea that e",
" is close to 1+",
" for small ",
". This is not true for large ",
". If you like you can draw the graphs and see for yourself."
] | [
"The natural log of a number ",
" is the power you need to raise Euler's number ",
" to to get the number ",
". ",
"That is, ln(A) = B, e",
" = A. ",
"It's used a lot in systems involving growth as the function e",
" is one where the rate of change of the amount of stuff is proportional to the amount ... | [
"For small x, e",
" is very close to 1+x. (since the slope of e",
" is also e",
" the slope at x = 0 is e",
" = 1. So 1+x is the tangent line of e",
" at the point (0,1)) Taking the log of both gives:",
"e",
" ~ 1+x",
"ln(e",
") ~ ln(1+x)",
"x ~ ln(1+x)",
"if x = A/B -1, and A/B ~ 1 means that... |
[
"Does Einstein's theory of relativity connect electric and magnetic fields?"
] | [
false
] | null | [
"Yes; namely under changes of inertial frames in relativity (Lorentz transformations) E and B fields mix into eachother.",
"Super minimal example to show this: static charge, there's only an E field. You change reference frame, it gets moving and therefore part of the E has turned into a B. ",
"Said in modern w... | [
"Yes! In fact Einstein's original paper on special relativity is \"On the Electrodynamics of Moving Bodies\" (well it's actually \"Zur Elektrodynamik bewegter Körper,\" but you get the point). A short description is that electrostatics (Gauss's Law) plus special relativity (the Lorentz transformation) give you elec... | [
"Yes, it's covariant. The potential is not gauge-invariant though, unlike F, and therefore it's not observable. A description of the physics using A is redundant because of the gauge symmetry, while directly using F has no ambiguity. However, the variational formulation cannot be done unless you use A as your funda... |
[
"Dan Freedman claims that newborn infants have distinct cultural differences. How is this possible?"
] | [
false
] | He did a study on newborns in the '70s and concluded that their different behaviors were cultural: | [
"Newborns though. A day old."
] | [
"Right, but how would parenting affect newborns?"
] | [
"Right, but how would parenting affect newborns?"
] |
[
"We all know that hot air rises, but my question is why the energy of the atoms is seemingly directed upward?"
] | [
false
] | null | [
"I think you have the reasoning confused here. Hot air rises because it has expanded. Charles law tells us that with pressure being unchanged, an increase in temperature means an increase in volume. The less dense air floats the same way that oil floats on water."
] | [
"This is not density-driven buoyancy but so-called ",
"granular convection",
". It seems odd to give an example in which the denser object can rise due to size differences when trying to explain hot air rising. The only similarity, it seems, is that something is rising."
] | [
"This is not density-driven buoyancy but so-called ",
"granular convection",
". It seems odd to give an example in which the denser object can rise due to size differences when trying to explain hot air rising. The only similarity, it seems, is that something is rising."
] |
[
"What are the forces that are causing this? (.gif inside)"
] | [
false
] | I saw this is a "WTF" thread, and I was wondering what caused it... it seems like it could be the result of a really intense vacuum? | [
"To test the car's resistance to an internal vacuum and to see that if it does implode, it won't throw shrapnel or anything like that I guess."
] | [
"You pump steam inside the tank car. As the steam condenses, it creates a vacuum. This vacuum destroys the car."
] | [
"This one was done on purpose as a demonstration to show the effects of pulling a vacuum on it. This can happen when the product is pumped out of the car but the relief valves are left in the closed position."
] |
[
"[Materials Science] If I wanted to leave a message for future denizens of Earth what is the most enduring media/method I could use?"
] | [
false
] | Words carved in stone? USB stick embedded in plastic? | [
"Here's an article about ",
"using Platinum and Sapphire",
". They hope it will last 1 million years."
] | [
"granite, possibly, although carving something on the moon is the most enduring thing I can think of."
] | [
"The oldest samples we have from Earth are zircons so that would be a good suggestion. For protection I would stick that zircon in a granite and then it should live a good long time."
] |
[
"Settle a bet: would lightning do anything to a tank?"
] | [
false
] | My friend and I are at an impasse. He claims that a lightning strike on a tank would, at the very least, disable its electronic systems. I, on the other hand, believe that the electricity would take the path of least resistance straight through the hull and into the ground. My contention is that modern battle tanks, developed during the Cold War, were shielded against EMP to make them better survive a nuclear blast, and that the electronic systems should thus be isolated from the hull itself. Assume, for this scenario, that the lightning strikes the hull and not an antenna, which we both agree would have deleterious effects on at least the radio systems. | [
"I'm going with \"nothing\"",
" for a regular ol' steel-armor-plated tank. At least, for some value of \"nothing\" -- I assume you don't really care if there's cosmetic damage on the tank.",
"Tanks with active armor are a different story, of course. Also, I don't know the electrical properties of DU armor - c... | [
"The tank hull would form a Faraday cage to protect the insides of the tank, this also protects any ungrounded circuitry in the tank.",
"As for shielding against an EMP - that is utterly irrelevant, the magnetic shockwave from an EMP is negligible compared to the voltage in a direct lightning blast."
] | [
"Because the tank has a metal frame, the voltage will go through the frame and since metal has very low resistivity the frame will conduct charge in a uniform way. Anything that is inside the frame is going to be protected as there will be an equal amount of charge on either side, so no current will pass through.",... |
[
"Is eating fruit important, or when people say 'fruit and vegetables', are the vegetables the important part of that?"
] | [
false
] | [deleted] | [
"Doing surveys to determine the benefits of diet is typically fraught with challenges presented by confounding variables, and the limited accuracy of self-reporting.",
"... What does the evidence suggest?",
"The evidence suggests that in the short term (like a year) humans can do just fine with very little in t... | [
"\"Good amount of sugar\" reads \"lots of calories\" to me, regardless of pancreas impact.",
"I suspect that's what he meant."
] | [
"The five portions of fruit and veg aren't exact so much as a convenient number of a food group that contains a lot of important micronutrients. Like rufus said, you can get (most of) these micronutrients elsewhere such as by rating the organs of animals, but eating some vegetables can be easier and cheaper than su... |
[
"How can you tell the temperature of an atom?"
] | [
false
] | I'm reading books on particle physics and I still can't figure out how you would find the temperature of an atom? Lets say a hydrogen atom. Is the electron in a higher orbit? | [
"A single atom doesn't have a temperature. By definition, temperature is an ",
" measurement of the vibrational energy of a ",
" of atoms or molecules."
] | [
"By definition, temperature is an average measurement of the vibrational energy of a group of atoms or molecules.",
"Almost... it's really a convolution of entropy (randomness) and energy (translational, rotational, vibrational, electronic, magnetic...).",
"Specifically:",
"T = dE/dS",
"That is, temperature... | [
"We can use the ",
"Kinetic Theory of Gases",
" to approximate it, but like previous commentators have said, temperature is really a macro property and not easily applicable to an individual atom.",
"From the Kinetic Theory of Gases, the temperature is",
"T = mass * average velocity / (3*boltzman's constant... |
[
"How far are we from curing cancer?"
] | [
false
] | And what are the biggest challenges we're having tackling this problem? | [
"Cancer is not a single entity but a category of many diseases with different underlying etiologies, and consequently, different targets for treatment. Even within any one organ system, like \"lung cancer\" there are many kinds of common and rare cancers that have little in common at the cellular and molecular lev... | [
"There have been tremendous breakthroughs for several types of cancer, including leukemia in kids and also breast cancer (a topic I'm working on) has seen lots of improvements in the last twenty years. ",
"For breast cancer, improvements in (early) diagnosis and improvements in treatment have meant the world of d... | [
"As a cancer researcher myself, I can say that while we are still not at a cure for cancer, we are at a turning point. There was a recent article in Cell titled \"The Evolving War on Cancer\" by Daniel Haber that discusses our current position on the war on cancer in detail. Below is a key summary of the article:",... |
[
"Serious question - how can I make my flatulence smell better?"
] | [
false
] | null | [
"Not likely. 1-2 liters/day would make him violently ill."
] | [
"4 eggs in the morning. but then again ive been doing that my whole life without problems."
] | [
"4 eggs in the morning. but then again ive been doing that my whole life without problems."
] |
[
"An average tennis ball floats in the centre of a hollow sphere made of extremely dense material, floating in space. Is the tennis ball \"squeezed\" by the sphere's \"gravity well\" toward the centre, or pulled outward by the gravity of the walls all around?"
] | [
false
] | In other words, if you have a hollow sphere made of, say, neutron star material, does the entire sphere make a impression in spacetime - ie, gravity is highest at the centre of the sphere? Or, does spacetime mirror where the mass is, meaning gravity is highest the closer you are to the walls, and lowest in the middle of the sphere? | [
"The tennis ball floats as if it was in space without any other mass around. The gravitational attraction from each side of the shell exactly cancels the attraction from the other side - this is called Newton's shell theorem. "
] | [
"Also, so long as the shell is a uniform sphere, the tennis ball need not be in the centre of said sphere. The gravitational field would be equal at all points within the sphere!",
"References:\n",
"https://en.wikipedia.org/wiki/Shell_theorem",
"\n",
"http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/sph... | [
"Have you heard of ",
"r/writingprompts",
" ?"
] |
[
"If you were stranded in the desert and all you had was a bottle of Tums..."
] | [
false
] | I'm learning about acids and bases in Chemistry right now and one of the most common examples of how to tame an acid is taking antacid tablets (such as Tums which is Calcium Carbonate). These tablets will turn the HCl in our stomachs (which causes heartburn) into water (and salt). My question is, if you were stranded in the desert with no water, but happened to have a bottle of tums, would the water produced in the reaction be sufficient enough to keep you from becoming dehydrated too quickly? | [
"No. Gastric acid is partly produced from the reaction: CO2 + H2O -> H2CO3 -> H+ + HCO3-. The neutralization of the acidic protons in stomach acid with antacid would produce bicarbonate, which can be converted back into water and carbon dioxide by carbonic anhydrase. In other words, this is the opposite reaction of... | [
"if you balance the equation you'll see that you're missing two H's and an O..."
] | [
"if you balance the equation you'll see that you're missing two H's and an O..."
] |
[
"Are sonic booms found in solids/liquids?"
] | [
false
] | If so, how do they differ in nature from the gaseous phenomenon, and where would they be found in practice. | [
"Wouldn't basically any liquid undergo ",
"cavitation",
" and become gas if an object attempted to pass through it at the speed of sound in said liquid? I would imagine you would run into a similar issue smacking two solid objects together at the speed of sound.",
"That said, the sound waves would still becom... | [
"Cavitation will still happen at some speed, there just won't be any vapor pressure (gas) in the cavities then."
] | [
"Yes, but as ",
"/u/Dubanx",
" points out, the pressure changes associated with the shock will transform some of the liquid to vapor, so it's inevitably going to be a mixture of solid/liquid and gaseous phenomena.",
"One situation where this occurs in practice is asteroids and comets striking planets. They'r... |
[
"How is it possible to identify different bombs by the radiation?"
] | [
false
] | I'm watching and in the movie, by analyzing the charred remained of Baltimore, they are able to figure out which EXACT weapon was used. From doing a bit of research, this seems to be an actual thing -- but there isn't a reasonable explanation. Thank you! | [
"One thing to be aware of is that only a tiny portion of even the most efficient atomic bomb is actually turned into energy. As shown in a previous thread ",
"here",
" these devices convert at most only about one kilogram (a bit over two pounds) of matter to energy. The rest of the material forming the bomb is ... | [
"It's called nuclear forensics. It's possible to detect if the nuclear device was uranium or plutonium in few hours, but detecting design, age (time elapsed since production or last purification)\n, production process and history may take several weeks or months. ",
"The process of figuring out the details can s... | [
"these devices convert at most only about one kilogram (a bit over two pounds) of matter to energy. The rest of the material forming the bomb is blown apart",
"Just to be clear: yes, that much matter turns into energy, but you have to split a lot more than 1 kg of atoms to get 1 kg of energy, because each fission... |
[
"Do athletes like Terrance Knighton, who have a high body fat percentage but great cardiovascular fitness, still run the risks of obesity-linked diseases?"
] | [
false
] | According to the CDC: Obesity increases the risk of many health conditions, including the following: Coronary heart disease, stroke, and high blood pressure. Type 2 diabetes. Cancers, such as endometrial, breast, and colon cancer. High total cholesterol or high levels of triglycerides. Liver and gallbladder disease. NFL defensive tackle, , is listed at 6'3" and 335 lbs. Judging by photos, I would think its's safe to assume that he has a high body fact percentage. While he doesn't have cornerback speed, he's still capable of . Keeping in mind that Knighton exerts those kinds of efforts upwards of 40 times per game, I would assume that he has higher than average cardiovascular fitness. There are plenty of players like this in the league ( is another example), so how are these men's health affected by their weight considering their excellent athleticism? | [
"http://www.ajconline.org/article/S0002-9149(11)03387-X/fulltext",
"In conclusion, National Football League players from the 1959 through 1988 seasons had decreased overall mortality but those with a playing-time BMI ≥30 kg/m2 had 2 times the risk of CVD mortality compared to other players and African-American pl... | [
"This may answer your question, but it deals with studies on sumo wrestlers (so its taken to even a farther extreme):",
"http://examine.com/faq/can-you-be-healthy-and-obese.html",
"Essentially, their extreme athleticism is not enough to counteract their risk."
] | [
"I played football in the SEC. Not pro level, but the next best thing. And yes, I had Olympic and other nationally recognized strength trainers. We burned for long periods of time without rest. It isn't 5-10 seconds on and 30 seconds - minutes off like playing in a game with commercial time.",
"We did drills runn... |
[
"Is there a reason to discourage appropriate usage of antibiotics?"
] | [
false
] | My six week old daughter was recently hospitalized with a viral infection and was given antibiotics in the course of her treatment. I've had several people comment on how horrible it is for a baby to have antibiotics. The nature of the comments indicated that antibiotics are a bad thing for people to take. I'm aware of the rise of antibiotic-resistant bacteria and understand that we may be entering an age where the efficacy of antibiotics is diminished, but is there a physiological reason why antibiotics should be avoided? Are there serious long or short term side effects? | [
"I’m glad you raised this question because it is extremely important to curb inappropriate antibiotic use for many reasons. Of course, inappropriate use of antibiotics leads to resistant bacteria, but like all medications, antibiotics have other side effects.",
"The side effects depend on the antibiotic. Just lik... | [
"I don't know if the highest proportion of resistant strains are produced from patients in the ICU. As an ICU physician, I do feel confident in saying that antibiotic use is usually justified because it keeps these patients alive, and we make every effort to narrow the specificity of the antibiotic down as soon as ... | [
"Of course, inappropriate use of antibiotics leads to resistant bacteria",
"Isn't it true that most resistant strains are the product of long term critical care, i.e. NICU,refractory infections, or long term care of immune suppressed patients? "
] |
[
"Why is light attracted to black holes if it has no mass?"
] | [
false
] | Does light have mass? Because how can it be pulled by gravity without mass? | [
"You're right that there's a contradiction here with ",
" gravity, which is what is taught in intro physics courses in high school and college. In Newton's physics, gravity is a force of attraction between two masses - which means that in Newton's physics, massless light is ",
" by gravity (OK yes it's more com... | [
"Exactly. Even though light is massless, it travels in a straight line. If you curve the space the light is traveling through, it’s straight line will curve along with it even though it has no mass. ",
"A black hole curves the space within its event horizon so much that the straight line bends towards its center ... | [
"Try thinking of it this way. Objects always travel in a straight line. Gravity can cause the straight line itself to be curved."
] |
[
"Can a star reform into a another star after it dies?"
] | [
false
] | My knowledge is that stars form from the compression of nebulae due to gravity untill it becomes super hot and eventually undergoes fusion. Once a star "dies out" and turns into a red giant and eventually another nebula, could this nebula form into another star? | [
"Short version: sort of... The elements released from a planetary nebula would diffuse throughout the neighborhood, and enrich existing molecular clouds with heavier elements. But most star formation regions are quite massive (",
"at least a few solar masses, up to a couple thousand",
"--see page 2.) And it's n... | [
"If the star went in a nova or supernova, it will rerelease the 'star stuff' which pockets together with other star stuff and eventually reached a mass where the body of mass can undergo fusion, starting a new star"
] | [
"what is the heaviest element our Sun producing? "
] |
[
"If I tried to run a computer in the vacuum of space, would it overheat or freeze?"
] | [
false
] | If I brought my desktop computer to space and managed to get it running (I'd imagine wall outlets aren't common there) would the chips overheat because the fan isn't circulating air through it? Or would they freeze/boil depending on whether or not they were in direct sunlight? | [
"Thermal radiation can occur in a vacuum. Its how the sun heats the Earth."
] | [
"Interesting question. Heat loss in space is often mistaken in popular media. The conduction of heat in space is low as a result of the lower particle density. Primarily objects lose their heat through thermal radiation. I would imagine the computer would overheat as conduction is the primary method of CPU/GPU cool... | [
"The same way they cooled the lunar rover: with a radiator."
] |
[
"What was the slowest observed wave we know of?"
] | [
false
] | I was just looking at some antibacterial gel, and it looked like a standing wave, but it doesn't appear to be moving. What is the slowest wave we've seen. It doesn't have to be an E&M wave, but could be a liquid wave. You don't need to historically know the slowest wave, you could give me a theoretical minimum if you wanted. | [
"It cannot be stressed enough: the planck scale has no other significance than being the limit where we expect quantum gravitational effects to be important for what is physically going on. It is NOT the smallest possible lenght."
] | [
"If you stretch the meaning of 'wave', you can include various long-term periodic processes like\n",
"Predator-prey dynamics",
" which oscillate over years, or the movement of planets (1 year for Earth to loop around the Sun ), or ",
"observe beats between two periodic processes with close frequences",
".",... | [
"I don't think there could be a physical limit to how slow waves can travel, nor can there be a maximum wavelength. Vibrations and waves are caused by a beautifully simple principle, and the physical incarnations of that principle have no end to their variety. \nOne interesting example is ",
"this timelapse of Sa... |
[
"Ask Anything Wednesday - Engineering, Mathematics, Computer Science"
] | [
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! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...". Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists. Please only answer a posted question if you are an expert in the field. . In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for . If you would like to become a member of the AskScience panel, . Past AskAnythingWednesday posts . Ask away! | [
"Highly unlikely. For one, quantum computers need to be cooled a lot, in some to temperatures 0.02 Kelvin (0 Kelvin is -273.15 Celsius). They are very hard to make and operate, thus cost a lot, d-wave is estimated to cost $15 million, although it's just an estimation by BBC. Then there is the problem that they don'... | [
"Most streets we build are made of concrete or tarmac, but they wear down rather quickly. Are there more durable materials being developed for better streets in the future?"
] | [
"I asked before at a bad time I think I got caught in the moderator. I would not blame anyone for putting the work thorium in the spam filter.",
"My cousin has started posting heavily about Thorium reactors recently. I've looked at some of it and the designs look like the old breeder reactor designs that were mad... |
[
"How did they discover that Europa had liquid oceans underneath its ice?"
] | [
false
] | I never understood the concepts | [
"From Wiki:",
"The first hints of a subsurface ocean came from theoretical considerations of tidal heating (a consequence of Europa's slightly eccentric orbit and orbital resonance with the other Galilean moons). Galileo imaging team members argue for the existence of a subsurface ocean from analysis of Voyager a... | [
"The short answer is that geologists sat down and created models to show how the surface features could be created by tidal movement. ",
"A person I've had the pleasure of working with over the years is, quite literally, the top authority in the world on this specific subject. He was the one who discovered this... | [
"Here is what I found on NASA's website: ",
"Why do we think that Europa has a subsurface ocean?\nThere are several strong pieces of evidence that suggest an ocean exists on Europa:",
"The magnetometer aboard the Galileo spacecraft detected signs of an induced magnetic field near Europa's surface, clear eviden... |
[
"Why are atoms the way they are?"
] | [
false
] | [deleted] | [
"The positive/negative charges hold the electrons and protons together, so without these opposite charges, the particles would just zoom past each other and there would be no atom. ",
"So the nucleus of the atom is a whole bunch of protons, but all protons have the same positive charge, and like charges ",
". H... | [
"I would not say that range of a force and strength of it are inversely proportional. The Strong Force behaves very differently to Electromagnetism and Gravity. I would look at ",
"This post here",
" for a good explanation."
] | [
"Why is the strength of strong force so much stronger than gravity, but gravity seems to have a much larger range? Is gravity's strength more \"spread out\" so to speak, because of its wider range?"
] |
[
"Is there any chance that manmade aid pollution will someday ground our flights in the same way that volcanic ash has this week?"
] | [
false
] | null | [
"Any chance? Sure, thermonuclear war with enough bombs could do the trick and be considered man-made pollution.",
"Is it likely from ordinary consumption, burning of fossil fuels? I would bet against it. Mainly as (a) there is a finite amount of fossil fuels that could be burned and currently with catalytic con... | [
"No.",
"The damage is due to silicate particles melting to glass in the combustion chamber. You need a lot of power to get such particles airborne, and to keep a critical density in the air as they settle out.",
"The atmospheric man-made aerosols do not have the composition nor the density to damage engines."
] | [
"A relevant quote: \"Thank god men cannot fly and lay waste the sky as well as the earth.\" - Thoreau"
] |
[
"If the Universe is about 13.82 Billion years old and some of the farthest galaxies, such as UDFy-38135539, are around 13 billion light years away how do we know they are not red-shifted because the light was emitted when the universe was still in its early expansion?"
] | [
false
] | To expand on this, could they be, in their preset, local time, moving toward us and how would we know? | [
"The universe is still expanding; it wasn't something that stopped early on, but something has, in fact, be speeding up as time goes on. ",
"There was a moment of extra-fast expansion, in the first fraction of a second, but there were no galaxies possible then."
] | [
"here the object was when it left",
"Only in the universal coordinate system at that time. This means if I have a point at x=0 (it) and x=1 (me), maybe when the light reaches me the sending object is at x=-0.5 and I'm at x=2.",
"Expansion of the universe is tricky."
] | [
"To answer this question we first need to realize that red or blue shift isn't due to the fact that the galaxy is moving toward or away from us; it is due to the fact that space itself is expanding, thereby stretching the light waves traveling through the space and causing them to shift toward the red side of the s... |
[
"In the event that the earth’s magnetic field were to “flip”; aside from compasses working backwards, what would actually happen that effects humans?"
] | [
false
] | null | [
"a lot of electronic would likely get screwed up/destroyed, even if they didnt have magnets in them.",
"When the magnetic field \"flips\", which would take a while, not an instantaneous thing to my understanding, there would be periods where the magnetic field that protects us from solar flares and ion bombardmen... | [
"Is there a way we could protect them? Am computater man."
] | [
"Most things can be protected by switching them off, and ideally disconnecting them from the grid."
] |
[
"What determines the reverse voltages of diodes?"
] | [
false
] | Recently been doing some research on early rectifiers and have learned that almost all common metal oxides will work as a diode, but usually at pretty low backward voltages. The most common were cadmium selenide and copper oxide, but improvised homebrew diodes can apparently be made with ferric oxide or zinc oxide. The issue with them always seems to be the high forward and low backward voltages, cadmium selenide (AKA "selenium rectifiers" in old radios and amps) is 1V forward and 25V reverse, while zinc oxide is 3V at best and copper oxide is often as low as 1V in reverse. Why is this? I know it's something to do with band gaps but how do those relate to actual voltages? | [
"Basically it's the potential required to start a so-called avalanche breakdown of the insulating layer. When a sufficient potential difference is applied across a diode in the reverse direction, it will cause charge carriers to accelerate. In avalanche breakdown, the charge carriers collide and free more charge ca... | [
"Doesn't this depends on whether it's avalanche or zener?"
] | [
"No, because all diodes exhibit both phenomena. Zener breakdown is a quantum mechanical phenomenon, where electron tunneling occurs. This will happen below the avalanche point.",
"When a diode is given a potential difference that exceeds it's peak inverse voltage rating, it will be avalanche breakdown that will b... |
[
"\"uranium is needed to make nuclear energy and nuclear weapons\", is this statement (from Pew poll) true?"
] | [
false
] | null | [
"Then yes, the poll is technically wrong."
] | [
"Fissile material is necessary for a fission reactor/bomb. Only two elements have isotopes that are feasible to use in these situations: uranium and plutonium.",
"A certain isotope of thorium is fertile, so it can be used to breed a fissile isotope of uranium. And as for that example of polonium, that wasn’t used... | [
"But \"nuclear\" just refers to the use of \"nuclear energy\", doesn't it? That includes radioactive decay energy. Not just fissibility.",
"The wikipedia page for ",
"nuclear powers",
" says \"The term includes nuclear fission, nuclear decay and nuclear fusion.\" So even simple radioactive batteries qualify a... |
[
"Did fungi ever engage in Endosymbiosis?"
] | [
false
] | A random question that came to my mind yesterday: As far as I know both plant and animal cells developed due to endosymbiosis, does this also apply to the cells of fungi? If yes than what exactly happened, they can't have chloroplasts inside their cells because they are not engaging in photosynthesis but are there mitochondria inside them or something completely different but similar in function? | [
"No fungi have mitochondria like ALL eukaryotes and received them in the same exact endosymbiosis event as ALL eukaryotes. That's not the same as what you stated."
] | [
"As far as we know, all mitochondria are the result of an endosymbiosis event that only happened once in the entire history of life on Earth. Rather than being acquired separately in animals, plants, and fungi, the origin of mitochondria dates back to some single-celled eukaryote that was an ancestor of all of the... | [
"Thanks for the correction"
] |
[
"What occurs in the body to cause instantaneous death?"
] | [
false
] | null | [
"\"Instantaneous death\" is not particularly well-defined. Indeed, \"death\" isn't particularly well-defined, and all the tests we do in order to try to figure out whether someone's dead take seconds, at least, to perform. So if someone ",
" die instantaneously then we'd never know whether they had or not."
] | [
"You're thinking of it like a heart attack, in which you feel chest pain and anxiety before a dysrhythmia, leading to death. Heart stopping (asystole) or any other life threatening dysrythmias will almost immediately cause unconsciousness because the brain isn't receiving enough blood (oxygen/glucose) from inadequa... | [
"That seems rather self explanatory, your body would disintegrate and you would no longer perceive reality due to a lack of sensory organs and a brain to interpret their data."
] |
[
"What causes color degradation?"
] | [
false
] | I was just wondering exactly how does natural light (sun) degrade (bleaching/white washing) images like posters or paint on a building? Is it the sun reacting to certain things here on the earth? Edit : Fixed spelling error | [
"The short answer is that sunlight causes irreversible changes in the compounds and molecules that gave a material its color in the first place. Due to these changes, the material gradually loses the ability to specifically absorb (and reflect) in the visible spectrum. The net result is a the tell-tale faded appear... | [
"Yes, glass can significantly reduce the degradation. The reason is that most kinds of glass are very good at blocking UV rays, which are the biggest culprits in promoting these chemical changes. For example, even a 2mm thick sheet of soda lime glass (the glass in common window panes) can ",
"block off virtually ... | [
"So then things like glass or plexiglass can block out certain spectrums of light and can either increase or decrease the degradation? "
] |
[
"I have COVID antibodies and have been donating plasma, will my body replace the antibodies that I donated (is there a finite amount)?"
] | [
false
] | I’ve gone 3 times, and curious if my body is replacing the antibodies I donate or not. | [
"Your body produces, on top of antibodies, memory cells. Thece \"memory\" cells are stored in your body and have the ability to produce the same antobodies when the body is re-infected. Antibodies tend to die overtime anyway and these memory cells tend to stay much longer."
] | [
"When you are exposed to the virus, your body will make memory B cells which produce antibodies and live inside germinal centers within your lymph nodes and spleen. These cells are always producing low levels of antibodies and will ramp up production when you are re-exposed to help fight the infection. These are lo... | [
"Thank you for your donations.",
"My mother believes she caught COVID-19 back in March. She got tested for antibodies a month ago and recently donated plasma. They told her she couldn't give it again because the antibodies had fades too much and typically start to fade after 90 days, although some people lose the... |
[
"Why is prediabetes reversible as opposed to type 2 diabetes? At what point does it become irreversible?"
] | [
false
] | Are these just labels on a spectrum of intensity? | [
"Prediabetes means you are at a stage where you have enough insulin to keep you normal at baseline, and only fails when you eat too much calories, especially sugar. ",
"Type 2 means you don’t have enough insulin that you will have abnormal blood sugar either all the time, or even with regular intake.",
"It is b... | [
"depends on how much insulin your body can still secrete. Once the overloaded beta cells die, they never recover. This is a progressive process. That being said the biological pathways for insulin resistance (the second key part of prediabetes and type 2 diabetes) seem poorly and incompletely understood. At least t... | [
"Once the overloaded beta cells die, they never recover. ",
"Although there is ",
"islet cell transplantation",
". So technically, even beta cell death is reversible using surgery."
] |
[
"If your body was completely hydrophobic (like in this .gif), would you be able to swim faster in water, or would you be much slower?"
] | [
false
] | If your entire body was coated in some hyrdophobic substance, like in for example, would you move quicker or slower in water? Would you be able to generate more or less pull? and would drag forces affect you more or less? Thanks! EDIT: Thanks guys, a lot of great information here! | [
"Okay. You would not suffer skin friction drag, but you would still be subject to pressure drag. Which might lead you to think you would be faster. \nBut you because you can't cause any friction on the water you can't propel yourself nearly as well. Most of the force generated when you swim isn't actually from the ... | [
"There's a lot of attention here, and a lot of wrong answers by people that know some fluid mechanics, but not quite enough to know the full relationship between skin friction and drag.",
" By ",
" I mean a material where there will be zero friction at the interface. This result is known as D'Alembert's paradox... | [
"I don't think I agree with your assessment: ",
"This is known as the venturi effect. If you cant drag water and cause this vorticity you can't propel yourself.",
"This is also a pressure effect, and skin friction shouldn't have much to do with that either. As long as your hands and feet leave a wake in the wat... |
[
"How far is the focal point for human eyes when resting?"
] | [
false
] | [deleted] | [
"The focal length going into the eye is 23-24 mm. Coming out it is about 17 mm. The difference is the refraction boundary at the cornea. "
] | [
"Huh? A focal point is at the focal length, it is the point of convergence for light that enters the lens parallel. "
] | [
"I believe what your asking about is dark focus. Or rather what would what would our eyes focal point be if there was no stimulus present? If you put someone in a room that has no stimulus for which we can focus, our eyes tend to accommodate about 1-1.5D. For a patient with no refractive error this would put thei... |
[
"Why don't we have plagues of locusts anymore the way we did in the late 1870s?"
] | [
false
] | null | [
"Interesting article",
" on the status of ",
" (the Rocky Mountain locust), with the possibility that it still exists, somewhere.",
"Over the past century, this disappearance has baffled entomologists and ecologists. The collapse came, after all, before the advent of synthetic insecticides, such as DDT, or ev... | [
"If I remember correctly (this all comes from my memory of some NatGeo special I watched years ago), it takes a specific set of environmental events to trigger grasshoppers to morph into locusts. I think a very wet growing season followed by a long, hot drought is the usual cause. ",
"I think it's been artificial... | [
"So this is in the USA, specifically in the Rocky Mountains right? The title and text of the OP should be edited and be more concise..."
] |
[
"Is there any reason as to why many horn-growing animals (moose, deer) shed their antlers once a year?"
] | [
false
] | null | [
"They are dead tissue once the velvet comes off, and generally, each year they come back larger, if the animal is in good health, so it is advantageous to show the status of the animal by shedding and regrowing. They also become damaged during the rut, and cannot repair themselves, so if they weren't shed and repla... | [
"I don't know why, but I do know that horns and antlers are not the same thing. Antlers are shed; horns are permanent."
] | [
"Antlers are bone whereas horns are keratin (hair)."
] |
[
"500 tons of phosphate leaked into the Nile river. What are the health risks?"
] | [
false
] | So 500 tons of phosphate were leaked into the Nile river stream as a cargo ship carrying the amount sank. What health risks are there to people drinking this water and is it possible for drinking water to be safe due to normal filtration problems? The ministry says its safe but they might be just saying that cause of political reasons. | [
"Well, there's not tons of information, but I certainly don't trust the ministry as quoted here:",
"The Ministry of Irrigation declared the state of emergency as a precautionary measure as ",
".",
"First, ",
" refers either to an ion (PO4",
" ), or to any of a huge number of compounds containing it. Witho... | [
"If they're saying that the phosphate spilled is \"insoluble\", it might be because it's some insoluble heavy metal salt, like lead phosphate, which would definitely be a health risk."
] | [
"It depends on the type of phosphate that was spilled. If it's phosphoric acid or or some tribasic phosphate salt, that would be more serious in the short term than something like dibasic sodium phosphate.",
"If the government is calling it insoluble as ",
"/u/sagan_drinks_cosmos",
" mentioned, that could be... |
[
"Why are the blades on wind turbines so long?"
] | [
false
] | I have a small understanding of how wind turbines work, but if the blades were shorter wouldn’t they spin faster creating more electricity? I know there must be a reason they’re so big I just don’t understand why | [
"A wind turbine doesn't really care how fast it is spinning as far as the power output is concerned. For example if you take a small electric motor, it will probably require 1% of a horsepower to spin at several thousand revolutions per minutes (rpm). A container ship engine rotates only at a few hundred rpm but ou... | [
"Other people have covered the idea that the longer the blades, the larger the crosssectional area, the more wind you can capture, but I want to go into some detail on the idea of how fast the blades should spin. ",
"So to understand this, first off it is important to note that there is a maximum possible wind tu... | [
"It's also worth noting that while a larger rotor has a greater power output, the spacing of the turbines from each other is also proportional to the rotor diameter. In fact both the spacing and power output are proportional to d",
" . So the maximum power output you can achieve per land area (i.e. MW/m",
" ) w... |
[
"How is radiation transformed into heat?"
] | [
false
] | Say we have a cloud of hydrogen gas in space with an average kinetic energy and a nearby star shines light through this gas. The electromagnetic waves with the right frequency will be absorbed by the hydrogen and re-emitted with the exact same frequency while all the other light is transparent to the cloud. If this is the case then how will the gas cloud heat up ( I'm assuming it will)? I'm also confused as to how solid objects become heated. I've read that it's helpful to think of the electrons in the solid as vibrating springs with certain frequencies and if EM waves have the same resonant frequency the springs with absorb that light and the vibrating will increase. Why is this process different from individual atoms absorbing and re-emitting photons (i.e why don't the vibrating strings re-emit the photon leaving the solid with no net energy gain)? | [
"I think some things need to be clarified. First, one of your statements is wrong.",
"The electromagnetic waves with the right frequency will be absorbed by the hydrogen and re-emitted with the exact same frequency",
"Each compound has its own ",
", that is which wavelengths it absorbs and how likely it is to... | [
"Is it actually momentum or is it the excited state of the atomic nucleus that imparts a small amount of kinetic energy? Is the wavelength has changed that means some of the energy of the photon has been absorbed into the nucleus which excites it, thus allowing it to move (causing heat radiation). Does that really ... | [
"Photons have momentum proportional to their frequency. Look up compton scattering for the experimental proof and a discussion of the implications."
] |
[
"Can the human eye detect a Gamma Ray Burst from a near distance? Or are Gamma Rays frequency too high?"
] | [
false
] | null | [
"The human eye can't see gamma rays, although at some point, the gamma rays may damage the eye enough so that you'd be able to know that something is happening.",
"That said, while much of the energy from gamma ray bursts is released as gamma rays, not all of it is. They are usually bright in the visual spectrum ... | [
"Human eye can only see things between ultra violet and infra red. That's why they are called such things. The lowest frequency we can see is red, and the highest we can see is violet. Anything beyond those are not in our visible range. Gamma Rays have frequencies much higher than violet visible light. "
] | [
"Well the very definition of Gamma Ray puts them outside the visible wavelengths. The visible spectrum is (roughly)from 300 to 700 nm (10",
" m). Gamma Ray's are on the order of less than 10 pm (10",
" m). As other posters have stated, events that produce gamma rays also tend to produce light at other wavele... |
[
"Before we cut our fingernails, what was their purpose and how long would they typically be?"
] | [
false
] | null | [
"We won't cease to have nails \"because of evolution\". Things disappear only if there is an evolutionary (i.e. survival) advantage to doing so. That's why we still have nails and male nipples."
] | [
"Farmers and tradesmen rarely if ever, need to cut their nails. "
] | [
"The fingernail helps the pad of the finger to maintain grip (it prevents it from rolling) so they still serve a function. They also represent the remnants of claws from our ancestors of course. Typically nails would not have grown terribly long in ancient times due to the large amount of manual labor the typical p... |
[
"x^2-y^2 = a* sin(x^2), what is special about a?"
] | [
false
] | I was just playing around with a graphing calculator and worked out that as a approached 7.789705767492725 from below you get a zero at around 2.77944 for x - y = 7.789705767492725 * sin(x ) or in other words 2.7794338 - (7.789705767492725 * sin(2.7794338 )) gets really close to zero. I figure there must be something special about those numbers in terms of some mathematical constants, but I can't work out what they are. | [
"Instead of working with x",
", let's see what happens with z=x",
". If y is zero, then the equation becomes z=a*sin(z). After moving things around a bit to get sin(z)/z=1/a, this happens when f(z)=sin(z)/z intersect the horizontal line at height 1/a. The graph of it looks like ",
"this",
". This means that... | [
"Thanks so much for your thoughtful answer. And thank you for introducing me to the function sinc(x).",
"What I do wonder about though is, in the the line of reflection between the greatest two zeroes of x",
" see ",
"here",
"Whatever a is the line seems to be down the line x = 2.77943382, or if there are n... | [
"i would not advise thinking of the \"greatest two zeroes\" of ",
" as reflections about ",
" for as long as you dont know what exactly is going on there. if you suspect a reflection to exist, examine it further, but dont allow suspicions to muddy the clarity of your process. ",
"i would argue that as ",
"... |
[
"If you made a spherical shape of magnets all on the negative side and put a magnetic bearing in the middle would it levitate?"
] | [
false
] | null | [
"What do you mean the negative side?",
"Metal is attracted to both the north and the south side of a magnet.",
"A magnetic bearing would have one side which is north and one side which is south. If you put it in a sphere with all the south facing in, one side would repel but hte other would ATTRACT and it would... | [
"Magnets with one pole do actually exist, physicists can engineer the poles in such a way. Smarter Every Day has a video on this, thought I'm unsure whether the video talks about magnets with one pole."
] | [
"Magnets with a single pole absolutely do not exist. This would be a Nobel prize to discover one. People have been searching for a very long time due to an argument about charge quantization by Dirac.",
"You can get things that sort of look like a magnetic monopole ",
" a material, a sort of effective monopole.... |
[
"How often can a person get dengue fever?"
] | [
false
] | [deleted] | [
"Not sure, but you certainly can get it more than once. I had always thought that subsequent infections have increased likelihood of haemorrhagic fever, but don't know a ref for that. So best to try not getting it more than once (and once is usually enough incentive to avoid A.Aegypti)"
] | [
"Infection with dengue provides some resistance to that serotype, but introduces the risk of DHF if infected with a different serotype"
] | [
"Thanks for the answer. Yeah I've had it officially 3 times and the fourth time is susceptible. ;)"
] |
[
"Our brains store so much information; is there a limit?"
] | [
false
] | [deleted] | [
"From the way that I understand it, it is definitely finite, but not in the way a hard drive is finite. I remember learning a theory before in which memory is frequently rearranged and patterns are recognized and stored (reminds you of .zip compression, no? :P )",
"Anyways, here's a little excerpt from an ",
"a... | [
"Yes. Information is a physical property and only so much can be encoded within a limited space or upon a given amount of mass.",
"Of course, our brains aren't ",
"black holes",
", so our limits are a lot less than the absolute ones. Estimating how much information a brain actually could hold isn't straight ... | [
"It depends on what you mean by \"information\". If you just mean the ability to record daily events that we observe/experience then there really doesn't seem to be a limitation for some unique ",
"people",
". These people can recall minutiae of of events every day that is mind-boggling. They literally do no... |
[
"In Earth travel, we use North, South, East, and West, plus altitude for three-dimensional travel. Since those are all relative to the Earth, what do they use for space travel?"
] | [
false
] | null | [
"Pretty much on every planet or moon it is possible to define North, South, East and West based on the body's rotation. Alternatively, they can be defined based on the Solar System's North and South (as the IAU did with Uranus, whose extreme axial tilt makes the rotational North opposite to the Solar System's North... | [
"Im a 6-DOF simulation engineer at NASA, so this is right up my alley. There are tons of different coordinate frames one can use to navigate 3D space, the key is know what kind of rotation matrix/quaternion you need to navigate from frame to frame. To name a few, there's topodetic, topocentric, PCI, PCR, J2K, M50, ... | [
"Being things tend to move in elliptical patterns I would have thought something like polar coordinates would be used. Is there a particular reason a Cartesian coordinate system is used? "
] |
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