title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why do the elderly respond to cold weather more than younger people?"
] | [
false
] | null | [
"Thanks for the explanation!"
] | [
"Thanks for the explanation!"
] | [
"15 degrees?!?! ...Do you mean Celsius?"
] |
[
"Why is sunburnt skin noticeably warmer to the touch?"
] | [
false
] | null | [
"Exactly. One of the main components of inflammation is heat (the other \"cardinal signs\" are redness, swelling, pain, and loss of function). This is due to increased blood flow to the area. ",
"Sunburns are inflamed because there has been trauma and cell death in the area. "
] | [
"I can't give you a medical reason but, as a very pale descendant of Ireland, I'm guessing that, since sunburn does damage to the outer layer of skin, the warmth is due to the red blood cells traveling to the area to begin the repair process. You may notice the same thing happens to an infected cut. The area around... | [
"Thanks for verifying that! "
] |
[
"Is iPhone X’s Face ID Infrared Safe?"
] | [
false
] | null | [
"Hi SirBeethoven thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the fo... | [
"‘Computing’"
] | [
"Computing"
] |
[
"Why are there fresh and salt water varieties of most aquatic life, but no freshwater cephalopods?"
] | [
false
] | There seems to be at least somewhat-analogous pairings in fresh and salt water for most types of aquatic life, but there doesn't seem to be a single cephalopod that lives in fresh water. Why are there no freshwater octopuses or squids? | [
"osmosis.",
"Freshwater dwellers have salty blood relative to the water around them. Without a mechanism in place to control it, osmosis would equalise salt concentrations between the animal and the water surrounding it, pumping salt out of the body and flooding it with freshwater. A sodium pump, like that found ... | [
"Great question! Echinoderms (urchins, starfish, sea cucumbers, brittle stars, sea lillies) also can’t be found in freshwater because they use seawater as their blood."
] | [
"That's a great explanation for the differences in biology, but I feel like it doesn't really answer the question. Is there something about cephalopod biology that's incompatible with that kind of sodium pump? Or did it just not evolve by pure coincidence?",
"Like starfish just use straight seawater as their bloo... |
[
"Do electrons rotate while they are circling the nucleus?"
] | [
false
] | [deleted] | [
"Electrons are neither circling the nucleus (strictly speaking) nor rotating on themselves.",
"The fact that they possess both an orbital angular momentum and an intrinsic angular momentum (spin) can therefore be seen as a bit confusing.",
"To better understand the origin of the first, you should know that elec... | [
"These are analogous to the rotation of the Earth around the sun and the rotation of the Earth around its axis",
"Careful here. There's truly no classical analogy to electron spin and making that analogy leads to incorrect physical intuition. "
] | [
"These are analogous to the rotation of the Earth around the sun and the rotation of the Earth around its axis",
"Careful here. There's truly no classical analogy to electron spin and making that analogy leads to incorrect physical intuition. "
] |
[
"Why is the expansion of the universe attributed to dark matter and not just momentum from The Big Bang?"
] | [
false
] | [deleted] | [
"You mean \"dark energy\" rather than \"dark matter\" - but yes, it's because of the acceleration of the expansion. Before the late 1990s, the expansion ",
" considered to be more or less just momentum from the Big Bang, with gravity predicted to slow the expansion. The expansion isn't slowing though, it's speedi... | [
"So, there's an interesting aspect of how gravity works. Imagine if the earth was a hollow shell, and you were inside of it. At first we would assume that the shell's gravity would pull us, but here's the thing: there is shell to the right of you, ",
" shell to the left of you. ANd the two opposing attractive for... | [
"yes, simply by ",
"newton's shell theorem",
"which states that ",
"If the body is a spherically symmetric shell (i.e., a hollow ball), no net gravitational force is exerted by the shell on any object inside, regardless of the object's location within the shell.",
"because we see isotropic expansion in the ... |
[
"Just how much \"stuff\" is there and how do we know?"
] | [
false
] | When scientists talk about knowing how many atoms/particles there are in the universe, does this mean in the "observable universe"? And how have they determined that amount anyway? I have heard that general relativity allows for the expansion of space faster than the speed of light, so is there stuff out there that is impossible for us to observe? Is it possible that our universe contains mass/energy that is beyond the scope of our observation? If this is true, and we were to travel instantaneously to a galaxy billions of light years away, would their observable universe look very different from ours? Would they be able to see galaxies that we can't see? Or do we know that the expansion of space faster than the speed of light has not happened yet precisely because we can still see the CMB? | [
"I can't answer all your questions, but I'll do my best to answer the ones I can.",
"When scientists talk about knowing how many atoms/particles there are in the universe, does this mean in the \"observable universe\"?",
"Yep. We don't really know how big the universe is (and to my knowledge it could very well... | [
"I'm not the OP, but thanks very much for this answer. On a related note, roughly how many atoms are there in the observable universe?"
] | [
"About 10",
" ",
"according to Wolfram Alpha",
". (In general, Wolfram Alpha's a pretty great tool for looking up things like this)"
] |
[
"Do you get blackbody radiation from a pure gas?"
] | [
false
] | What are the characteristics of a material that allow it to emit blackbody-like radiation? In a cloud of molecular gas (i.e., a star forming region), will you only get blackbody radiation from the dust? Or will you also get blackbody radiation from the gas? | [
" object",
" at a temperature higher than 0K will emit some blackbody radiation. To put it a bit more precisely, all objects will emit some thermal radiation, the spectrum of which is weighted by ",
"the blackbody spectrum",
". But the actual spectrum you get will depend on the material in question. The reaso... | [
"Again, it depends on exactly what kind of fire we are talking about. But for instance if you are talking about the flame of a candle, or the a typical fire in a wood burning fireplace, the answer is yes. As the organic components start burning, they will spit up a bunch of soot. This soot in turn will ",
"radiat... | [
"A hydrogen/oxygen fire is blue, and can be barely visible.",
"Here's",
" a picture of a Space Shuttle main engine firing. You can see the blue of the Hydrogen flame in the rocket's bell, but can barely make the flame out against the background."
] |
[
"What is \"reality\"? How much do we really \"see\", and how limited are we by our senses to the true nature of the universe"
] | [
false
] | [deleted] | [
"But how could they change from 17 to 27 if time is just a relative illusion?"
] | [
"Hate you. So much."
] | [
" You are standing ",
" to a perilous cliff, off of which many a would-be philosopher-king has tumbled to an ignominious death. Take about four steps back ",
"The short and direct answer to your question is that none of that could possibly matter less, and thinking about it is a complete waste of time.",
"Tha... |
[
"It is often said that humans are no better at detecting lies than chance; are we any good at judging intelligence?"
] | [
false
] | null | [
"Hi ana1ytics thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the follo... | [
"'Psychology'"
] | [
"Psychology"
] |
[
"How do engineers prevent the thrust chamber on a large rocket from melting?"
] | [
false
] | Rocket exhaust is hot enough to melt steel and many other materials. How is the thrust chamber of a rocket able to sustain this temperature for such long durations? | [
"There are a few different designs to cool the “bell”. Some have small tube-like paths throughout for fuel to travel through it, removing some of the heat and pre-heating the fuel. Some use ablative material that slowly flakes off removing some of the heat with it."
] | [
"Yes,",
"regenerative cooling with fuel",
") is the main answer."
] | [
"I'm sure they know what they're doing; it just ",
" dangerous: \"Our new car gets rid of the inefficient radiator-and-coolant system—now all those red-hot metal parts are cooled directly with gasoline!\""
] |
[
"Why is our body able to fight certain viruses/diseases and eventually develop anti-bodies but can't for others?"
] | [
false
] | When it comes to diseases like measles, in most cases, once our body fights off the disease we are granted lifetime immunity. When it comes to the flu, immunity is mostly temporary because of mutation. But what about viruses such as HSV or HIV/AIDS where we have to rely on medication for the rest of our lives to keep fighting? Why is our body unable to recognize the virus and fight it to develop natural immunity over time? | [
"HSV and HIV are able to hide from the immune system in very different yet effective ways. HSV (as well as other herpesviruses) infects and becomes latent in neurons. Our nerves are typically left alone by our immune system because they last our entire lives, you don’t want to target nerves with an immune response ... | [
"People do develop antibodies against HIV—that's the basic sense of \"seropositive\", literally, serum-tests-positive for anti-HIV activity. The blood serum is the liquid, watery part of the blood, after removing cells and other particles. So \"seropositive\" means having antibodies; which is to say the immune syst... | [
"This is fascinating and a really great explanation, thank you for sharing!"
] |
[
"How come the exact same flight computer, RAD750 is being used on both Curiosity (2011) and the Mars 2020 rover, have there been no improvements in almost 10 years?"
] | [
false
] | null | [
"It is extremely expensive to qualify stuff for space applications, even more so when it is for a flagship science mission. For electronics normal testing will include:",
"In some cases the tests need to be performed with the same production batch as the one that you are going to fly.",
"As you can see this is ... | [
"It's more than that, actually. The RAD750 was released in 2001 and was first flown in the Deep Impact probe in 2005. Why are we using 20 year old technology?",
"Beyond the cost of building new technology, as ",
"/u/electric_ionland",
" says, you have to ask what the value of having a faster processor would b... | [
"For space application it is usually either a pendulum hammer and a swing table or actual explosives. You can sometime do it with sin bursts but it is not as good."
] |
[
"If you had a pen, a paper, and ten seconds, what's the biggest number you could write? What's the best tactic?"
] | [
false
] | null | [
"You will be interested in the following read : ",
"Link",
"This gives a very long and detailed answer to this exact question."
] | [
"It depends on how long it takes you to write different numbers. 9 is bigger than 1, but you can write a 1 really fast.",
"Regardless, exponentials get big fast. 9",
" is 387420489 and 9",
" is 2.9512665e+94 which is huge. But far larger is the number 9",
" So writing just 5 characters you could write the n... | [
"Probably something like \"the 11111th Busy Beaver Number\" is the biggest well defined (although in this case unknown) number you could write down very quickly.",
"According to the rules, I have fifteen seconds. I write:",
"S",
"(G), where G is graham's number, exponentiation is functional iteration, and S(m... |
[
"If I sat in a tube of 100% pure ethanol/alcohol, what would happen to me?"
] | [
false
] | Assume I didn't have any breathing issues. | [
"This is way off topic, but since it's ",
"/r/askscience",
" I figure no one would really mind. ",
"Having a 100% ethanol solution is extremely difficult (technically, a perfect 100% ethanol is essentially impossible) but you can get very close with some tricks. When you have a mixture of water and ethanol, d... | [
"The last death of 2004 on this list",
"You would die. You'd absorb it across your skin, as ethanol can diffuse through a cell membrane, and being that there's a point at which your BAC is too high for continued bodily function."
] | [
"And it would hurt. A lot. Not that I've tried it. But don't try it. Really. At least not with vodka."
] |
[
"Is it possible that what we perceive as bad smells is the brain's interpretation of possible danger? For example, consuming spoiled milk or inhaling toxic gasses that may cause disease."
] | [
false
] | null | [
"Absolutely! Over time humans have learned which smells relate to disease or danger. This is why rotting flesh smells so horrible to us. A mini-scale version of this happens when you get sick after eating (or perhaps drinking too much of) a certain item. Your brain associates that taste/smell with being sick an... | [
"I have often wondered if this aversion or attraction response applies to colourful food items as well. Such as finding colourful vegetables attractive. Mind you, there are some very poisonous bright red berries out there..."
] | [
"I had always asked myself this question. Good thing you asked. Great question!"
] |
[
"What causes the core of a nuclear reactor to glow?"
] | [
false
] | Is it the reaction, or is it the actual fuel itself? | [
"Cherenkov radiation from electrons moving faster than the phase velocity of light through a medium (for example, water). "
] | [
"Cherenkov radiation has nothing to do with an acceleration of the particle. It is similar to a sonic boom for light where constant supersonic speed will produce it as well."
] | [
"Cherenkov radiation has nothing to do with an acceleration of the particle. It is similar to a sonic boom for light where constant supersonic speed will produce it as well."
] |
[
"[Physics] How many times have we found the Higgs-Boson?"
] | [
false
] | Okay, as much as my knowledge goes, we have only found the Higgs-Boson at CERN and also that the ratio of number of positive experiments vs negative experiments is really poor. That is, number of failed experiment >> number of successful experiments. Now, I could be wrong. But I would stand by that I am not. So in this case, we are completely going against the scientific method. Higgs-Boson is yet to found in a lab other than CERN and we hardly seem to find it even after having found it already once. How come the scientific community accepts this? You would say that CERN has reputation, I would say that this is a bias and science requires that other labs/teams get the same result. We should atleast get the number of successful experiments higher than the failed ones. You have any thoughts? | [
"The Higgs boson was found at the LHC (as opposed to the Tevatron or elsewhere) because the LHC provides a higher center-of-mass energy. The mass of the newly-found Higgs boson is completely consistent with it not having been found at previous experiments. So no, the situation is that the number of \"failed\" exper... | [
"That was a detailed and juicy answer. Thanks buddy! Really appreciate you helping me."
] | [
"The answers already here are quite full, though there is one interpretation of the phrase \"That is, number of failed experiment >> number of successful experiments.\" which wasn't mentioned.",
"That is that it is a very rare occurrence that the Higgs is produced (and detected) in the LHC compared to the total n... |
[
"How and why does the last electron in the outermost shell of an atom determine what element it becomes?"
] | [
false
] | [deleted] | [
"It doesn't - its the number of protons in the nucleus that does"
] | [
"It's not so much the final electron as the total number of outer-shell electrons. These are the ones that are most available to take part in chemical processes such as bonding or ionisation, and so different numbers of outer-shell electrons will lead to different behaviour. For example, carbon has four outer-shell... | [
"Umm... What? Electrons have nothing to do with what element a given atom is."
] |
[
"How does water become super clear in the wild? What happens to suspended solids, algae, and plankton?"
] | [
false
] | There's a photo that showed up on the front page that showed crystal clear water in a stream ( ); some of you may have seen images of the water off the coast of the Maldives, which is so clear row boats in the water look like they're floating in air. How does water get this clear without filtration and sterilization in the wild? Why doesn't algae and other life and biological residues fill it up and make it cloudy? In the case of the Maldives, aren't there plankton in the water? In the case of the stream in Sweden linked above, you can see dead grass in the water; if it flowed there across any sort of land and if the stream or pond has dead plant matter in it, why hasn't it carried suspended biological residues into the water? (And lastly, is it possible to simulate those processes for man-made ponds?) | [
"If the water is completely lacking nutrients then nothing will grow in it and it'll stay clear. Tropical ocean water is nutrient poor, and the Swedish mountains (the Scandes) are composed mostly of limestone. Lime is used to reduce acidity in fertilizer polluted lakes, so I'm assuming it causes the water to become... | [
"If you look closely at the wrist, you can see the waterline, showing that the hand is actually submerged in water."
] | [
"I have dived in water this clear, the water I dived in was subterranean, and I filmed the source. So in this case the really cold water from a limestone area was freshly flushed through the lake. If this came from snow melt, or subterranean sources, then there is no place to pick up the detritus in the water. It w... |
[
"[Engineering] How are the wings on large commercial planes able to support multiple turbine engines and jet fuel without collapsing?"
] | [
false
] | [deleted] | [
"Short answer is that they're built strong enough to handle it.",
"The answer that will blow your mind a bit is that the wings would need to be STRONGER if the engines were mounted elsewhere. The wings produce the lift, which counteracts gravity, so the weight of the engines along the wing actually counteracts t... | [
"It's pretty amazing.. I'm a pilot myself, and the light planes that I fly are the equivalent of aluminum cans. We're talking skin thicknesses of .025\" to probably .040\" in the higher stressed areas. That's the thickness of a few sheets of paper..",
"I'm always a little amazed coming from what I fly when I bo... | [
"Certification for commercial aircraft requires the structure to handle a static load at least 1.5 time the once-in-a-lifetime limit load. Check out ",
"this",
" Boeing 777 test to failure. Deflections of the wing are in excess of 30ft from resting position at the time of failure for other models! The wings ar... |
[
"What would actually happen if the Higgs boson was found? What impact would this have on physics?"
] | [
false
] | Also, more importantly, what if it isn't found? | [
"What is it?"
] | [
"The Higgs boson? A really long discussion. The shortest possible answer I can think of is that the photon, W and Z bosons are all a family of particles. Except the photon is massless and the W and Z bosons are ",
" heavy. The Higgs mechanism is the process by which the W and Z bosons get their mass and the photo... | [
"Not a physicist, but I think the situation is that physics will go on as usual when it's found.",
"If it ",
" found in the expected energy range, there will be a lot of heavy drinking and late nights, tufts of hair torn from scalps in frustration, as thousands of scientists try to figure out a workable solutio... |
[
"With our current knowledge, is there a maximum speed a spacecraft could travel?"
] | [
false
] | I understand that it is theoretically possible to get arbitrarily close to c, and that c can never be reached or exceeded by anything with mass. However, with our current understanding of energy and propulsion systems (both current and theoretical) is there a realistic maximum speed a spacecraft could reach? | [
"The fastest man made object:\n\"NASA'S Juno Mission spacecraft will slingshot around Earth towards Jupiter, accelerating to 25 miles per second along the way and becoming the fastest man-made object in history. A .50-caliber bullet travels at about half a mile a second, by contrast -- nowhere near the blistering s... | [
"You seem to be well informed, let me ask you a question. I read recently that theories has been developed for the possible construction of a drive that could allow for faster travel working on the warp bubble principal. I believe it wasn't thought to be practical because of the energy consumption the device would ... | [
"A little bit of both. ",
" under relativity it could exist, but we have no evidence to suggest that it does.",
"Although when you state it like that, it's kind of like saying that unicorns ",
" exist, but we just haven't found ",
" yet either. Current science suggests that such a substance is nothing more ... |
[
"Why does diarrhea have the potential to hurt the rectum so terribly?"
] | [
false
] | null | [
"So we would stop putting dangerous things up there and live longer."
] | [
"So we would stop putting dangerous things up there and live longer."
] | [
"So, is that actually what causes the burning sensation after eating spicy foods that give you diarrhea? Or are you also getting burned by the capsaicin?"
] |
[
"What are some of the *smaller* mysteries in science right now?"
] | [
false
] | We'd all like to know what dark matter is or how to cure cancer, but what are some of the coolest small mysteries out there in science right now? Stuff like some metal behaving in thus-far-unexplained ways in a magnetic field or a chemical reaction doing unexpected things in zero gravity or light from some star having unexplained spectral components -- stuff like that. And let's not limit this to physics :) | [
"What happens in the final seconds of cytokinesis. Scientists know that the cells separate (obviously) but truly have no idea as to the physical aspects of the divide. It is a biophysics research topic at my university."
] | [
"We still do not know what group of Gymnosperms (seed plants) evolved into the flowering plants. Fortunately, there are a few promising theories, but the fossil \"smoking gun\" has not yet been found. Most Paleobotanists set the date for this evolutionary split sometime in the Late Triassic period, 245–202 million ... | [
"Why Misophona happens. ",
"Misophonia is essentially developing anger, even rage when specific sounds are heard. Usually ordinary sounds like chewing, breathing, tapping fingers, coughing, it can be anything really. But nothing happens when the person is doing these things themselves. ",
"Reactions are complet... |
[
"How do \"Ninja Rocks\" (Al2O3 Ceramic shards from sparkplugs) shatter glass so easily?"
] | [
false
] | Aluminum Oxide (Al2O3) Ceramic has a Moh hardness of 9, and tempered glass is what, like, 6? But that isn't the whole story. How does the structure and surface tension of the glass come into play? How would one protect their car windows from this? Would a custom sheet of InvisibleShield work, or is there something by 3M that's substantially cheaper? In case you've never heard of Ninja Rocks: It's the tiny ceramic shards of a sparkplug that are thrown at a car window for quick and easy breaking and entering. It's crazy how tiny an effective piece is. | [
"Basically anything that's hard enough and sharp enough to make a deep scratch in the glass will cause it to fail catastrophically. The tempering process concentrates stress in the outside of the pane, which inhibits crack propagation. Unless the crack is large/deep enough, in which case, the glass tears itself apa... | [
"Do you have any kind of source for that claim, because it doesn't seem very likely (hence the downvotes, I assume). Tempered glass doesn't generally make a loud noise when it shatters, anyway."
] | [
"I will have to look for it. The police officer who took my statement asked if I heard anything. They found a broken spark plug head next to the glass. he said if they did it right it does as I mentioned. He wanted to know because if there was noise it could have been amatuers."
] |
[
"Do Nucleic Acids have anything at all to do with Cellular Respiration?"
] | [
false
] | Does DNA or RNA have any business in the process of Cellular Respiration? Thank you in advance. | [
"ATP, or adenosine triphosphate, is obviously composed of the nucleoside adenosine, which is in turn composed of the nucleic acid adenine and the sugar ribose. ATP is the main product of cellular respiration, produced via glycolysis and at the end of the electron transport chain from ADP. So yes.",
"DNA and RNA p... | [
"Directly, no. Obviously the DNA and RNA encode the proteins involved in the process, but other than that, they play no role. DNA and RNA are primarily in the nucleus of the cell. Cellular respiration takes place in the cytoplasm and the mitochondria. "
] | [
"I needed that point made clear, thank you!"
] |
[
"What classifies a sickness as the \"flu\" and why do we have flu seasons?"
] | [
false
] | null | [
"The flu is caused by the influenza virus. It is uniquely distinct from many other pathogenic viruses that might produce similar symptoms. Flu seasons are in part caused by the cyclic ways our society responds to changes in the actual seasons. Wet rainy/snowy weather tends to push people into closer contact in i... | [
"The actual Flu is caused by the virus Influenza. However, people tend to misuse the term a lot because there is a lot of illnesses that cause similar symptoms(bit of a fun fact, a lot of symptoms you often experience during illnesses are often not caused by the pathogen, but by your own immune system reacting to i... | [
"Thank you! Very informative"
] |
[
"Neil deGrasse Tyson in his AMA said quarks only come in pairs and that if you wanted to separate them the amount of energy needed is the exact amount to spontaneously create another pair out of thin air. How does a proton get 3 quarks without leaving a freely floating one somewhere?"
] | [
false
] | Link to his quote: | [
"The quote:",
"2) That Quarks come only in pairs: If you try to separate two of them, the energy you sink into the system to accomplish this feat is exactly the energy to spontaneously create two more quarks - one to partner with each of those you pulled apart.",
"This is a mistake, or possibly an oversimplific... | [
"I'll try explaining it with reference to this diagram:\n",
"http://www.quantumdiaries.org/wp-content/uploads/2012/06/tau_decay.jpg",
"I know it looks weird, but it'll get covered. So, to look at an example of what's happening here. So, we start with that particle on the left, which decays, leaving a down quark... | [
"More complex combinations might also exist but until recently there was no evidence for them. See this[1] "
] |
[
"How are \"super-organisms\" like termite and ant colonies able to evolve new behaviours?"
] | [
false
] | [deleted] | [
"Actually ant communities can shun individual members. Some ant colonies perform basic healthcare by isolating and banishing ants with contagious fungal infections. They're literally picked up by healthy workers and carried out of the nest.",
"Similarly there's actually remarkably little direct communication betw... | [
"If you think that's cool, you should check out ",
"ants that do agriculture",
" and ",
"ants that take slaves",
".",
"How are individual members of a hive/colony-type system able to deviate from their normal behaviours without risking being shunned by the other members of their community?",
"All ants i... | [
"One of my biggest \"whoa\" moments on this topic was when I drew a parallel between a human body and an ant colony; the main difference is that the body is a big connected lump and an ant colony is a bunch of non-physically-connected insects. Intelligence can emerge from a network of neurons that have more-or-less... |
[
"Can anyone explain how mind over matter appears to reduce pain?"
] | [
false
] | Some people say that mind over matter can actually reduce the amount of pain you feel. Does this actually work? If so how? | [
"1) Pain is your body screaming for attention. If you divert your attention to something different, you have less space for noticing pain.\n2) Adrenalin surge (such in fight or flight response) can actually reduce your perception of pain. If you find a way to trigger an adrenaline spike, you will feel less pain, si... | [
"Hey i think that the nature of pain is diverse. There is a signal that come frome the painfull point and reach different part of the brain. \nOne part is the sensitive one associated with the point on your body and the overactivation of this part induce pain. But there is another interesting part that is activated... | [
"Yes this does work! When we stop focusing on the pain, it becomes just another stimulus in the many stimuli of our environment. There is a proven theory that you remember how painful something is only by its last few moments. I know there was some testing done where subjects are exposed to a certain amount of high... |
[
"How do we check if something has \"taste\"?"
] | [
false
] | The calls it a "colorless, odorless, non-toxic, inert, monatomic gas". How do we know it's tasteless? I hardly imagine anyone putting liquid helium, which boils at 4.2K, on their tongues. | [
"Elements in a gaseous state can still find themselves making their way towards your tongue. Take gasoline, for example; you don't have to drink the stuff to know what it tastes like because you can still taste them fumes. The same principle applies for helium - if you ingest a portion of it (I.E., sucking on a b... | [
"Aside from noting \"this substance appears to be toxic\", I'm not entirely sure. That really opens up a whole can of ethical worms, though."
] | [
"Ah, that simple.",
"Does this not cause problems related to exposure? What if you were checking something's taste and it turned out toxic? "
] |
[
"At a quantum level, does distance become discrete also, like energy?"
] | [
false
] | I know that at a quantum level, energy is transferred only in discrete amounts. I'm wondering if the same becomes true of distance - is there a level where two discrete, non-equivalent points exist such that no intermediate point exists between them? | [
"This one gets repeated often.",
"The Planck length unit is not magical. It's just a very small unit of distance. It should not be taken as evidence that space is quantized."
] | [
"there's no evidence to suggest that it does. Some beyond-standard physics proposals suggest that it may, but we would need evidence to confirm any of those."
] | [
"In some theories, \"yes\". Here are two examples:",
"1) A theory called loop quantum gravity (LQG), which attempts a canonical quantization of general relativity (GR). Just like momentum and position of a particle become operators in ordinary quantum mechanics, things which are numbers in classical GR become ope... |
[
"I'm a geneticist, but I'm curious. Of the other geneticists out there, how do you think genome sequencing will change clinical care and how long will it take?"
] | [
false
] | null | [
"Well, a few months ago, I heard a lecture from a researcher at UT Southwestern, ",
"Dr. Michael White",
" talk just about his approach to finding cancer drugs that were specific to a patients given genetic mutation that was causing the disease. There are a lot of papers that you could look through there, but y... | [
"Did you also listen to this discussion on NPR today?"
] | [
"This may be more suited to ",
"/r/asksciencediscussion"
] |
[
"Why isn't there muscle cancer?"
] | [
false
] | We hear all the time about brain cancer, skin cancer, lung cancer, breast cancer, stomach cancer, etc., but why do we never hear of malignant, cancerous tumors from developing in muscle tissue? Is there something unique about the makeup of muscle fibers that prevents abnormal growth? EDIT: I'm specifically referring to skeletal muscle and why rhabdomyosarcoma (RMS) is rarer than other types of cancer. (Thanks ) | [
"There are- rhabdomyosarcoma, for example. ",
"It's comparatively rare though because there isn't much turnover of cells in the muscle, and they don't get much exposure to carcinogens. Any lining of the body has a high rate of cell division, and that's where errors creep in. ",
"Imagine photocopying the instruc... | [
"Wow thanks! So this is also why bones and ligaments aren't afflicted with cancer as often because they're not primarily composed of living cells?"
] | [
"Pretty much. There are lots of living cells in bones and ligaments, but many of them don't do much in the way of division once you're an adult. ",
"Leukaemias and lymphomas are kind of bone cancers though- they're due to those changes effecting the source of the blood cells, namely the bone marrow. ",
"What's ... |
[
"How do we calculate the wavelength of spectral lines for elements other than Hydrogen? Or is this just something we observe and use as a fingerprint?"
] | [
false
] | Context: I'm a teacher trying to relate neon signs to spectroscopy and the study of distant stars. I have a decent understanding how we can use the Balmer-Rydberg series to calculate values of the emission lines given off by hydrogen, but can we apply this to other elements? What about neon? | [
"The hydrogen atom (and ions with only a single electron) have remarkably simple analytic equations which you can solve for the energies of all of the excited states.",
"No other atom is this simple. As soon as you have more than one electron, you've broken some of the nice symmetries of the system, and you've go... | [
"You use a computer to crank through the math of quantum mechanics. ",
"But just to be clear, the Balmer series is a RESULT of quantum mechanics and falls out of solving the Schroedinger equation for a nucleus of charge 1 and 1 electron system. If you want to know helium then you simply repeat the calculation f... | [
"Well, you would need to solve the Schrodinger equation for the atom in question which is tough. There are approximations you can make so that the equation reduces to the hydrogen case. You can also explain-away terms on the equation of you understand why they're irrelevant based on the assumptions. For example, we... |
[
"How plausible is radioactively enhanced evolution?"
] | [
false
] | Could we take a separated but large population of the human race and expose them to high levels of non-lethal radiation in order to increase the rate of mutation in their genetic code. Understandably the majority of the mutations would be terrible and more often than not would result in horrendous forms of cancer. But provided that the population reproduced quickly enough how likely would it be that either the surviving population was resistant to that radiation or some favorable mutations occurred. Maybe this would be better thought of involving rats since they reproduce more quickly and the obvious ethical dilemma. Has anything like this been attempted before on any species? | [
"We already do that.",
"Link"
] | [
"I would suggest to use bacteria, since they don't have such a complex DNA for starters, and they have a reproduction rate that is a lot higher (and with humans and rats you would have to mutate the sperm cell or ovum to really get the mutation going on by reproduction). ",
"Also you would be able to keep a much ... | [
"Started thinking about the odd creatures around chernobyl, which led to me deciding to build a race of super crickets."
] |
[
"How widespread is empathy among different species of animals?"
] | [
false
] | Mammals and birds tend to live in groups, and display some level of sociability. I've seen in documentaries lions helping each other when a member of the pride gets injured or something. What about reptiles or fish? I ask, because I encountered on , and I can't really think of this in any other way than a good Samaritan helping his fellow turtle out of a bad position. Is that a misinterpretation, or is this kind of behavior way more common than I had originally thought? | [
"It's actually a very realistic representation on animal behaviors. One concept that I had trouble learning about in biology courses was idea of altruism. It's basically the most severe form of selflessness and absolute helpfulness. For example, if I jumped in front of a bullet for someone, disregarding my well-bei... | [
"Well, to modify this a little, complete altruism--the willingness to sacrifice one's self for any member of the species--is selected against. The commonly used example is the outdated idea that lemmings would commit mass suicide to prevent overpopulation. All it takes is one lemming to decide not to do this, then ... | [
"In the past few years we've found increasingly compelling evidence of what humans describe as 'altruism' in a number of species. Perhaps the study that received the most press was one using rats, in which it was found that a rat will go out of its way (physically exert itself, or even give up the opportunity to ea... |
[
"When healing from a cut or gash (may or may not require stitches), what happens to the damaged blood vessels? Do they reconnect perfectly, are new ones formed, or do damaged veins and capillaries just have a dead end now?"
] | [
false
] | null | [
"Small blood vessels (capillaries) will be stimulated t grow back into hypoxic tissue by growth factor proteins that the hypoxic cells send out. This is called angiogenesis, and it happens all the time. For a skin cut, that's about it. ",
"Large blood vessels are more complicated. This is called vasculogenesi... | [
"Both. When you get cut most blood vessels will reattach albeit not always in the exact same location. However there won't be any dead ends for long, because the body will reabsorb the material in the blood vessel to make a new one. Think of a pipe that gets broken, you can use pieces of the broken pipe to build a ... | [
"Like House? "
] |
[
"How much power does the 49ers new stadium lose from it's massive solar panels being red?"
] | [
false
] | as opposed to being black? | [
"I can't find the specs, but consider the following:",
"If the panels are red, then that means that the higher energy photons are being absorbed while red is being reflected.",
"The photoelectric effect is energy dependent. It the photoelectric cells are not activated by red light, no matter how much red light... | [
"Are you suggesting that 25% efficiency for a PV system is bad? Because typical values for most available systems are ",
"well below that",
". 25% is damn good for a PV system."
] | [
"Are you suggesting that 25% efficiency for a PV system is bad? Because typical values for most available systems are ",
"well below that",
". 25% is damn good for a PV system."
] |
[
"Why exactly do humans, and presumably other animals, perceive different wavelengths of light as different distinct colours?"
] | [
false
] | Why have we evolved to perceive them at all? Why is the perception of distinct colours needed? | [
"One prominent theory for color perception is to recognize good food sources, for instance, young (greener) shoots and leaves, flowers. Better color discrimination improves the ability to recognize them.",
"http://gandalf.psych.umn.edu/groups/gellab/Wurm93.pdf"
] | [
"Polychromatic sight provides a wide array of evolutionary benefits over monochromatic sight. Differentiating food sources from morphologically similar inert or poisonous materials ",
" you touch, smell, or taste them is highly advantageous. Distinguishing a predator's color in a morphologically uniform visual fi... | [
"Color emitted is a by-product of chemical composition, thus it is not illogical to infer that by the time polychromatic sight evolved there were distinct differences in chemical composition that might result in a distinct color for distinct organisms. ",
"Remember for plants that it is most likely that pigments,... |
[
"Can fire burn while submerged in liquid oxygen?"
] | [
false
] | For the sake of the question, a candle. | [
"Yes, and you'd better stand back."
] | [
"Okay - but could a fire burn if encased in solid oxygen?"
] | [
"Almost 12 hours and no one posted the ",
"Man From LOX",
"?",
"The heat from a candle is enough to vaporize some of the liquid oxygen, and use it to accelerate the combustion, which produces more heat, and the chain reaction continues until the fuel is exhausted. You do not want to fool around with LOX. ",
... |
[
"Lightning \"Duration\" from Back to the Future"
] | [
false
] | null | [
"Each strike lasts a few dozen microseconds, and a \"bolt\" usually has a few strikes separated by 30-40 milliseconds. ",
"You'd basically have zero leeway, and the technique in the movie would never work. What he should have done is arrange a long rail system, so Marty would have several hundred feet of connecti... | [
"Oh yeah, I never thought about that. Maybe the wheels have to be turning at a certain rate in order to engage the time... module... things? Course then you could just hook it up to the transmission and do it at a lower speed. Or maybe just have a \"do time travel\" button.",
"Hmmm, anyway, thanks for the info - ... | [
"I think it had to go 88 relative to the earth. "
] |
[
"Has teen acne been around since prehistoric times? Did cave-dwellers have zits? Or is it related to modern eating, exercise, pollution, etc.?"
] | [
false
] | null | [
"Based on responses here it made me wonder, are there cultures in the world that have more or less acne than others?? Like if you compared the average teen in USA vs the average teen in India, would one have more or less than the other??"
] | [
"According to ",
"this article",
" modern hunter-gatherers have much lower incidence of acne than industrial peoples, although the causes are not known. I can't vouch for the article, but it's thoroughly referenced",
"Edit to actually address the question: it's a reasonable inference from this that prehistori... | [
"There's have been studies showing certain ethnicities/races seem to be more acne prone due to their physiology causing some to produce more sebum than others. Of course environmental factors also play a role so it's not all down to genetics but there seems to be something to race and acne"
] |
[
"Why does the body stop growing?"
] | [
false
] | [deleted] | [
"I know ",
"this",
" is not a scientific source but it makes a few valid points.",
"First off, a human ancestor (or maybe it was a competing species) did grow much larger at one point about 1.5 million years ago. It was too inefficient because the surface area of the skin was not large enough to cool them off... | [
"Growing takes a lot of energy. Once you've reached optimal size, it makes little sense to waste energy by getting bigger."
] | [
"I asked this question today a couple of hours ago! Upvote for some answers."
] |
[
"Does a magnetic field affect water molecules?"
] | [
false
] | As water molecules have a small magnetic moment | [
"MRI doesn't align water molecules though - that is, it doesn't really force the molecule to adopt a particular orientation with regards to the magnetic field. What lines up is the nuclear magnetic moments of the hydrogen atoms in water."
] | [
"Correct. This produces a repulsive force. Although it is very weak, given a strong enough magnetic field, you can ",
"levitate water or things mostly made of water",
". "
] | [
"Correct. This produces a repulsive force. Although it is very weak, given a strong enough magnetic field, you can ",
"levitate water or things mostly made of water",
". "
] |
[
"Why is the earth's crust thinner under the oceans?"
] | [
false
] | When teaching my students about plate tectonics, I got asked why exactly the crust was thinnest under the oceans and thickest under mountain ranges. The mountain ranges one is fairly easy to explain, but a long Google search later I still can't come up with a good explanation. Can anyone help me out here? I promised them a definite answer tomorrow :) | [
"Oceanic crust, forming at mid ocean ridges and subducting at the trenches is like a conveyor belt",
". It maintains a relatively constant thickness, 7km +/-, due to the melting/cooling/insulation as described by Sycosys.",
"What he/she did not address is why there is a much ",
"thicker continental crust",
... | [
"What about the obvious explanation that areas where the crust is thin will have lower elevations than areas where the crust is thick, and water will fill the areas with low elevations?",
"It doesn't explain why the crust underneath the oceans is thin: but it explains why the oceans are above the areas where the ... | [
"The oceanic crust is formed at the mid-oceanic ridges as mantle heat forces rock to the surface. As the mantle pushes up, this crustal rock cools at a fairly uniform rate/thickness of about 7km. ",
"The reason it works out this way is that the underlying temperature of the mantle is directly related to how thick... |
[
"Question about gravity"
] | [
false
] | The more massive the object the more gravity the object has, makes sense and I get that (hope that is right). Had one of those TV science shows on in the background and they were talking about pulsars, neutron stars, etc. The mass of a star compressed to something 10 miles across or compressed to the size of a house. This is where I had that RCA dog in front of the phonograph moment. The show said that when the star is compressed to such a small size the gravity becomes extreme. So is gravity in fact an effect of an amount mass per a unit of space? The mass of a star, spread out over the volume of a star, has a certain deformation effect on that volume of space. The same mass of the same star, concentrated in the volume of a neutron star, has far greater deformation of the volume of space since that volume is so much smaller. Not just how massive but also how much space that mass occupies? So amount of "stuff" plus how much space that "stuff" takes up in space determines the how strong gravity is? | [
"I think some brain cells just clicked. Thank you. ",
"If I stand on the 'surface' of a very dense object, I effectively very close 'to all of it' so I experience more gravity. If I stood on the surface of an object with the same mass but dispersed over a very large area, I'm standing next to 'far less of it' ... | [
"Given an arbitrary distance from 2 objects of the same mass, you will feel the same gravitational force. A denser object simply allows you to get closer to its gravitational center with all of its mass being \"below the surface\".",
"If you shrunk the earth to the size of a marble, the orbits of all of the satel... | [
"Remember the movie \"Despicable Me\", when Gru shrank the moon? If someone did this, and truly compressed the moon down to the size of a pool ball, yet it had the same mass, there would be no significant change in its orbit, or the earth, and the moon would still cause about the same tides on earth. It's gravitat... |
[
"Wondering what Jupiter would look like without all the gas in its atmosphere"
] | [
false
] | Sorry if I may have screwed up any terms in my question regarding Jupiter, but my little brother asked me this same question and I want to keep up the "big bro knows everything persona". | [
"You cannot think of Jupiter as some kind of Iron based - or telluric (terrestrial) kind of body with a massive atmosphere surrounding it. \nIf the core is believed to be a massive iron soup, much hotter than the core of the Earth, it is so BECAUSE of the inward pressure caused by the massive amount of gas of the a... | [
"We're not sure, but it's thought to have a rocky core but we do not know exactly what the makeup is. We do not currently posses technology capable of surviving the pressures of diving into Jupiter's atmosphere.",
"Here's a good overview from Wikipedia: ",
"Jupiter: Internal structure",
". Encourage your li... | [
"Generally, ",
"Brown Dwarfs",
", which are the Jupiter-like bodies who ",
" made it to stardom, start at around 13 Jupiter masses, and run all the way up to around 90 Jupiter masses. Brown Dwarfs typically fuse deuterium and (the bigger ones do lithium ",
" fusion), but they can't do hydrogen->helium, so t... |
[
"Is there a fixed amount of matter in the universe?"
] | [
false
] | I've been wondering, since there is no way to destroy/create matter, does that mean that there is a fixed amount at least in the observable universe? Thats all really, I pretty straight forward question I couldn't find an answer to on google. | [
"Is there a fixed amount of matter in the universe?",
"No -- matter can be created and destroyed in a number of processes, such as ",
"pair production",
", ",
"fusion",
", etc. So too can (rest) mass be created and destroyed.",
"The related conservation law is the law of conservation of energy. Since ... | [
"Create/destroy is not the right word. Matter and energy can be converted into other forms. Fundamental law of physics is we cannot destroy matter. Law of conservation of mass."
] | [
"Create/destroy is not the right word. Matter and energy can be converted into other forms. Fundamental law of physics is we cannot destroy matter. Law of conservation of mass."
] |
[
"How did such a diverse Universe form from a Big Bang singularity?"
] | [
false
] | I only have a basic understanding of the fundamentals of this, but what I'm wondering is since at the point of or just before the big bang all matter was a part of the singularity and I'll assume uniformly compressed, why did it not form a perfectly ordered universe? Since there would be no outside interference (I'm assuming again) this disorder would have to come from within. So what caused this disorder? Was it the matter itself, was the "bang" decentralized, or something wildly different? | [
"The diversity that we observe in the Universe today was likely seeded after an epoch of rapid expansion (called inflation) in the early moments of the Universe. Although the Universe was extremely homogeneous and isotropic at that time, quantum fluctuations caused small overdensities which, by gravitational collap... | [
"Don't forget that there have been generations of stars before the current stars which have seeded the current galaxies with the different diverse elements."
] | [
"What LV426 said.",
"The ",
"cosmic microwave background radiation",
" is ,in a way, an image of these fluctuations."
] |
[
"How accurate is Path Integral Formulation?"
] | [
false
] | So Path integral formulation is how people calculate the most probable route for a particle to take. But, how accurate is it? I mean, how good is it at reliably calculating the route a particle will take? Are these the type of calculations they would do at CERN to make particles cross paths? | [
"well the universe just doesn't have the certainty that appears to be a part of classical physics. (",
"Then again it doesn't exist in classical physics either",
")"
] | [
"What is your background? The math of the path integral formulation is considered to be advanced so this is generally only discussed in post-graduate level textbooks. If you want the main concept but not all of the details, a section in Merzbacher's QM ",
"textbook",
" explains it in a neat way, and the rest ... | [
"it won't tell you ",
" path a particle will take. all it outputs is the likely probability of certain outcomes over others. And yeah, it works really well."
] |
[
"What happens underground as more and more oil is extracted?"
] | [
false
] | My understanding is that to extract oil from normal underground oil fields, explorers need to pump water instead, to replace it. What happens down there as we extract all those millions of barrels of oil around the world? Will the underground earth strata not get destabilized somehow? | [
"Oil extraction from conventional reservoirs (reservoirs that don't need fracking for production) can lead to land subsidence. In particular in coastal areas, this can lead to flooding. It can also lead to the damage of buildings and roads. It is thus common practice to inject water to fill the pore space that was ... | [
"With regards to \"sucking\": there's not a vacuum pump at the top, so perhaps \"squeezing\" would be a better description. A vacuum wouldn't help much, anyway, because surface pressure (14.7 psi) is already quite low compared to typical reservoir pressures, which can measure in the hundreds or thousands of pounds ... | [
"With regards to \"sucking\": there's not a vacuum pump at the top, so perhaps \"squeezing\" would be a better description. A vacuum wouldn't help much, anyway, because surface pressure (14.7 psi) is already quite low compared to typical reservoir pressures, which can measure in the hundreds or thousands of pounds ... |
[
"Do solar systems have an electric charge?"
] | [
false
] | I've been reading about lots of stuff lately which has included atoms, the strong and weak forces, and electrons not really being per se. I've also been reading articles like and thinking about space, and scale. I can't help but notice that what is happening in the vacuum of space sounds a lot like the micro-swaps of information between protons and neutrons that creates the force that binds them together and leads to the detectable charges we understand as electrons. It just seems like vacuum is demonstrating the quanta information exchange we see at an atomic scale, with suns and planets functioning as de facto protons and neutrons, which makes me naturally wonder if this creates a charge (or multiple charges / "electrons") for a solar system, or maybe even further at a galactic scale. Is it turtles all the way up and down, so to speak? Or do we only see the electron effect of built up charges from quanta-style interactions at the atomic scale? Or, do I not understand any of this even close to how things actually work, and I should probably just go back to playing video games and smoking pot? | [
"I think the reasons for the solar system having a net charge are a little more mundane than that, actually. In general, solar systems coalesce out of a big cloud of gas and dust that is scraping against itself and generating pockets of static charge, similar to how clouds build up a static charge before equalizing... | [
"I feel like there are a couple of different questions blending together here. As to whether the solar system acts like an atomic system with the sun/planets/sundry stellar bodies acting as fundamental particles, the answer is essentially 'no' (or at least, it lacks many of the features of an atom). ",
"In the ar... | [
"On another note, it is possible (probable, even) that our solar system has a net electric charge relative to other far away solar systems.",
"It may be that this is really the answer I was looking for, and the answer given is effectively \"Yes\", but I want to unpack all of that a little bit more and make sure I... |
[
"Why does carbon absorb so much visible light?"
] | [
false
] | As it is known, the colors that we observe with our eyes depend on what type of light wavelengths are absorbed by the mass of an object, being white no absorption at all, and black almost complete absorption. Carbon is very black and I wanted to know why does it absorb so much radiation or types of wavelengths in the visible light. Thank you in advance. | [
"Visible light is absorbed by a material when it can excite an electron from one energy level to another. If the energy of a photon is equal to this energy gap, it will be absorbed (in the simplest case - there are some additional selection rules that complicate this). So in simple terms, carbon absorbs a lot of ... | [
"Well, thank you very much for such a thorough explanation. I definitely forgot about diamond and it helps explain the reasons behind this phenomenon.",
"As a follow up questions. Do you know what are the wavelengths of energy absorption by graphite and amorphous carbons? I know the absorption of light for this s... | [
"In addition to what ",
"/u/pyrophorus",
" explained, we should not forget just how much the morphology of the surface or particles of a material can change the appearance. ",
"Consider a piece of polished platinum compared to ",
"platinum black",
". Likewise, consider the color of soapy water in a vial v... |
[
"Is Pluto still growing? I know it passes through the kuiper belt so it's still making alot of collision right? Does that mean it's still adding mass? Planetary sci."
] | [
false
] | I was watching story bots with my kids, the one where they talk about how planets form that's what brought up the question. | [
"No. Most planetary mass was added by slowly accreting smaller particles into the proto-planetoid from the proto-planetary disk. This process has long since finished as any material left un-accreted when the Sun 'turned on' would have been blown away by the stellar wind. ",
"Collisions will have different effects... | [
"There’s a big difference between what we imagine proto-planetary disks to be like and the present day Kuiper Belt. While I’m sure collisions between bodies still occur, the objects in the Kuiper Belt have, by now, settled into stable orbits around the sun, and there is enormous amounts of space between them. Forma... | [
"All planets are gaining mass from space debris raining down on them, but the rate is negligible. Earth gains about 50,000 tons a year from dust and meteorites falling into it, but it also loses about 100,000 tons of atmosphere a year so there's a net loss of mass."
] |
[
"Have we ever ran out of a natural resource?"
] | [
false
] | null | [
"Three that come to mind are all animals that were hunted to either extinction or nearly, all because of European expansion into North America: Stellar's sea cow, the passenger pigeon and the bison.",
"In all three cases, the animal at first seemed like an inexhaustible source of easy meat. European hunting equ... | [
"Old growth (I.E. Large sizes) of hard woods. My parents had a dining table made of a single piece of maple split in half so the wood grain mirrored on each side. You just can't find that today except antiques or recycled."
] | [
"I remember reading a few years ago that we would soon deplete the entirety of the world's helium supply. The most recent article I can find about it is ",
"here",
".",
"EDIT: Apparently, ",
"there is some disagreement",
" in the scientific community about whether a mass helium shortage could become a pro... |
[
"What could be the first signs of intelligent alien life?"
] | [
false
] | In the science subreddit i've been reading about the 5 earth sized planets that live in their respective star's habitable zone. Is there any possible way that we could confirm intelligent life on one of those planets (or any other planet) by making some observation here on earth. Science fiction has told me aliens will make their presence known by either showing up in spaceships, or by sending us some radio message, but both of these situations seem pretty unlikely. What if (for example) an alien race flooded their atmosphere with some synthetic element. When we turned our mass spectrometers towards those planets would we observe a situation that could not possibly exist naturally? Would it actually be strong evidence that intelligent life was responsible? Or will scientists pretty much have to assume that any weird observations have natural explanations? What other reasonable observations could we make from afar that would be strong evidence for alien life? | [
"http://en.wikipedia.org/wiki/Wow_signal"
] | [
"Oh shut the fuck up please.",
"Why do you think our evolution is so special? Wherever extraterrastrial intelligent creatures have evolved, I'm sure they went through the same thing: agressively domaniting their own biosphere etc."
] | [
"I had never heard about this, fascinating. Thanks for the link!"
] |
[
"Where does the mass go when not conserved in chemical reactions?"
] | [
false
] | I have read that mass changes in chemical reactions, for example through making and breaking bonds, but it is too small to detect. In balanced equations for non-nuclear reactions, there are the same number of protons, neutrons and electrons on both sides. If the equation is balanced, where is the mass change? Do the electrons/neutrons/protons slightly change their mass, or is the mass change hidden somewhere else? | [
"For example, a take a reaction like ",
"2H",
" + O",
" -> 2H",
"O.",
"The mass of one water molecule is smaller than the sum of half the mass of H",
" and half the mass of O",
".",
"Or even more simply, combining two oxygen atoms to make O",
", the mass of one O",
" molecule is a tiny bit small... | [
"In the nuclear case, the changes in mass are easily detectable. ",
"Masses can be measured very precisely, for example with a Penning trap. And you can calculate the difference between the mass of the bound nucleus and the sum of all the individual protons and neutrons. We call this the \"mass defect\", and ther... | [
"Or is mass a property of a system and not actually a property of the separate protons/neutrons/electrons that make up the system?",
"Yes, exactly."
] |
[
"How are space elevators supposed to maintain their speed when transporting mass from earth to the orbit?"
] | [
false
] | Because of newtons first law, the object that is being moved towards the counterweight would require horizontally (or rotational) effecting force in order to maintain it's route. I came into this conclusion because the counterweight orbits the anchored body and it should turn around the body faster than the body itself and applying vertical force to the climber doesn't cause it to gain horizontal (in this case rotational) speed. The speed required must be gained by slowing the counterweight which could lead to an imbalance and possibly break the whole system If what I said was true, how are physicists planning to overcome the slowing caused by carried objects? | [
"They steal the energy from the spin of the earth in the same way that when you spin a sling in takes energy from your hand. The entire line is under tension as the counter weight is past geostationary orbit. It's being flung around."
] | [
"No...",
"A stable space elevator has its effective* center of mass slightly above geostationary orbit and has a constant tension in the cable even at sea level. Raising a payload won't change that. Raising the payload accelerates the payload in forward direction and slows the elevator, making it lag behind sligh... | [
"The counterweight must be ",
" heavier than the travelling carriages and their cargo, one reason folks talk about capturing an asteroid and parking it in the appropriate position.",
"Since we'll presumably have things going in both directions, returning carriages/cargo will require a force in the other directi... |
[
"Do animals have to learn how to swim like humans or are they just born with that ability?"
] | [
false
] | Swimming in humans is something that must be taught and it is not something that we are just instinctively able to do. Do animals like jaguars or tigers that swim and use the water for hunting but are not dependent on water have to teach their young how to swim? If these types of animals are not exposed to water or not taught by their parent, do they instinctively know what to do or would they drown? | [
"Babies cannot swim instinctively. When placed in water their survival reflexes force them to move their arms and legs but babies will drown. They cannot hold their breath and cannot keep their heads above water. Thrashing is not swimming. Do not put babies of any age near water without strict supervision."
] | [
"Babies cannot swim instinctively. When placed in water their survival reflexes force them to move their arms and legs but babies will drown. They cannot hold their breath and cannot keep their heads above water. Thrashing is not swimming. Do not put babies of any age near water without strict supervision."
] | [
"So is it likely that we lost this ability to swim as we became less dependent on water bodies as a resource and the natural ability to do this as a baby is just a redundant evolutionary thing?",
"I just wonder if we are unique in this situation or if an adult tiger for example would drown if it weren’t exposed t... |
[
"What differentiates two similar elementary particles?"
] | [
false
] | If elementary particles are the fundamental building blocks of everything, this means that they themselves are not made up of anything but themselves. So what is it that distinguishes, say, two distinct up quarks? | [
"Two particles of the same type cannot be distinguished, they are ",
"fundamentally identical",
"."
] | [
"What distinguishes them is that one is over here and the other is over there. But it does not make sense to ask what would change if they swapped positions, as though they had identities. There may be a high probability of detecting an electron at position 1 and at position 2, but you can't say that electron 1 is ... | [
"u/RobertEtCeleritas",
" 's explanation is perfectly accurate, but allow me to build a bit.",
"Forewarning, gonna approach this from a Quantum Field Theory perspective, and I am not a professional, I just have hobbies.",
"So, on top of what was already mentioned, which is that particles of the same type are i... |
[
"Since planets rotate around suns and suns around galaxies, could we be feeling the effects of relativistic time dialation in relation to other planets?"
] | [
false
] | The news release about Voyager I got me wondering about this. We know that time dialates as an object approaches the speed of light, and iirc mass increases. Is it conceivable that we on earth are already feeling these effects, and that we could come across a planet of similar size and composition as Earth, but time and mass are completely different due to its planetary and solar orbit speeds? Edit: maybe I mean solar and galactic orbit speeds. Edit 2: and what does this mean for our observations of distant parts of the universe if our galaxy is careening along at a high speed? | [
"And the time taken to make one revolution is the same for both. ",
"That's where you're going wrong: the galaxy isn't a solid body. It doesn't need to have the same period per revolution at every radius. The inner parts take less time to do a revolution than the outer parts. This isn't possible for a pancake or ... | [
"One key concept in time dilation/special relativity is that there is no preferred inertial frame of reference. Also, mass equivalence is a misleading concept that has been largely abandoned by physicists. ",
"Other than that, I'm not really sure what you mean about observing an Earth-like planet. In general t... | [
"Our solar system is orbiting the centre of the Milky Way at around 250 km/s. An object near the centre of the galaxy would be revolving at a much slower speed than us. Let's say they are orbiting at 100 km/s, the difference is still 150 km/s (2000 times slower than light).",
"Although these aren't exactly close ... |
[
"Quantum Physics Question: Is the state 1/sqrt(2) | 0> - 1/sqrt(2) | 1> equal to -1/sqrt(2) | 0 > + 1/sqrt(2) | 1>"
] | [
false
] | Sorry if this isn't the right place to ask. If we have the two canonical states on 1 qbit. |-> = 1/sqrt(2) | 0 > - 1/sqrt(2) | 1 > |+> = 1/sqrt(2) | 0 > + 1/sqrt(2) | 1 > If you invert the |-> state you will get -1/sqrt(2) | 0 > + 1/sqrt(2) | 1 > This is not the same as |-> right? It would be its own thing -|-> , or is there a simplification. Sorry for the uninteresting question, but I don't have anyone else to talk through this stuff with. In other words -|-> is not equal to |+> or |-> right? If I was to take the eigenvectors of a Hamiltonian matrix, I could not say that a base state is |-> if I got -1/sqrt(2) | 0> + 1/sqrt(2) | 1> as an eigenvector. | [
"In other words -|-> is not equal to |+> or |-> right?",
"It's not equal as a vector, but it ",
" equal as a state. This is because the difference between -|-> and |-> is just an overall phase of pi (e",
" = -1), and states that differ by an overall phase are indistinguishable. Note that this does ",
" mean... | [
"Actually, it would be an eigenvector with eigenvalue L. Let's just call the state -|-> ",
" to make readability easier. Then ",
"(-|->) = ",
" for any scalar ",
".",
"We know that H",
" = L",
". Then let's look at H(",
"). For this we have",
"H(",
") = ",
"H",
" = ",
"L",
" = L(",
"),... | [
"It was for a homework question, but it wasn't this exact problem. This is just a subproblem that I needed to complete the whole thing. Not trying to cheat; I'm trying to learn. "
] |
[
"Why are acoustically guided weapons an option in the ocean but not in the air?"
] | [
false
] | [deleted] | [
"Ships are extremely slow (say 15 m/s / 30 knots) compared to the speed of sound in water (1500 m/s). What that means is that acoustic detection is practically instantaneous -- when the sound waves hit you, the target hasn't moved far.",
"Warplanes travel a significant fraction of the speed of sound (or well abov... | [
"To add, EM waves don't travel very far in water and so you can't really use them to track targets."
] | [
"Also the speed of sound in water is significantly higher ( over 4x ) than in air, and can propogate over longer distances."
] |
[
"How satellites measure underground water level ?"
] | [
false
] | How do satellites estimate the underground water level ? What changes in local environment signify higher underground water level ? | [
"Using ",
"gravimetry",
".",
"The maps are based on data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites, which detect small changes in the Earth's gravity field caused by the redistribution of water on and beneath the land surface. The paired satellites travel about 137 miles (220 km) ... | [
"That's fascinating! How do we create the sensors to be so precise? "
] | [
"I'm not too familiar with the exact instrumentation on the satellites but a basic gravimeter consists of a mass hanging from a spring. By measuring how much the mass causes the spring to expand/contract you can calculate the change in the force of gravity acting upon the system. That's the principle at any rate.... |
[
"What is the black spot that was on a CERN diagram? is it just a blotch or dust particle that got picked up?"
] | [
false
] | [deleted] | [
"That is where the beam passed through a ceramic screen on its way to the beam dump. The beam dumps are long, water-cooled rods of carbon encased in steel, designed to absorb the energy of the beams when they get ejected out of the LHC. Each beam can contain around 150 MJ of kinetic energy, which is about 10% that ... | [
"Do you have any more context for that photo?"
] | [
"It's a photograph that displays on this page after the beams have been dumped and before new beams are injected",
"https://op-webtools.web.cern.ch/op-webtools/vistar/vistars.php?usr=LHCBDS"
] |
[
"Is imposter syndrome prevalent in scientific communities?"
] | [
false
] | null | [
"If you go on and meet personally your profs, do PhD, etc, you will see how the whole thing is set up, that most of everybody is just normal people with stupid days and they usually look super smart on a tiny slice of knowledge that they have spent the last 15-20 years on (so no wonder they can blow a BSc student o... | [
"While I can't tell you whether it occurs more often in scientific than in other communities, I can at least assure you that quite a number of people I've talked to in the scientific field feel that way. \nIf I were to find a reason for that, I assume that by acquiring all that detailed knowledge about certain proc... | [
"Every skilled profession has to deal with imposter syndrome."
] |
[
"Where to find ground-based Ultraviolet spectrum data?"
] | [
false
] | I am looking for text files or xml or some kind of database which has ground based measurements of ultraviolet light. Something which has irradiance vs. wavelength. I have seen a lot of plots of the spectral irradiance at the surface even at ultraviolet wavelengths but have not been able to find datasets that these are made from. | [
"If you can get hold of '",
"', I'm sure it would be in there. "
] | [
"I think you are (or were, this thread is 3 months old!) looking for the ",
"AM1.5g",
" (air mass 1.5, global irradiance) spectrum.\nedit: (",
"more data",
")"
] | [
"Thanks! That was exactly what I was looking for with good resolution; it will still be very useful in the future.",
"I ended up using the irradiance in space and multiplying by the transmission obtained from different sources and interpolating down to one nm resolution for the UV range.",
"All our readings en... |
[
"Why does abstaining from porn/masturbation/orgasm temporarily decrease as opposed to increase libido?"
] | [
false
] | [deleted] | [
"I think the reason we might assume libido to increase is because we intuitively accept the idea that our behavior is controlled by basic drives (hunger, sex, etc) and that we work to return these levels to some kind of homeostasis. This is essentially what the psychoanalysts argued with their \"steam engine\" theo... | [
"Well I have no evidence or research to back this up, but I would have assumed that it would be temporary - at least for most people. This is due to the simple fact that 1) there are many, many cues which can trigger a behavior that can be difficult to get rid of for ingrained patterns (which is why it's hard to sh... | [
"Well I have no evidence or research to back this up, but I would have assumed that it would be temporary - at least for most people. This is due to the simple fact that 1) there are many, many cues which can trigger a behavior that can be difficult to get rid of for ingrained patterns (which is why it's hard to sh... |
[
"Does it matter environmentally if we lose rare species? Why do we try to conserve rare species?"
] | [
false
] | null | [
"Webs do best with many buttons for nature to tweak. When you reduce the web to just a few species, the web falls apart, especially when faced with great change it must respond to. Do this enough and our entire planet goes sterile in many regions. A famous example is loss of wolves from Yellowstone and then elk ... | [
"From a scientific standpoint, nothing presents a better basis for technological and medical advancement than reverse-engineering existing biological structures.",
"There are many instances where a limited number of animal species have been observed to manifest unique abilities. If those rare species are lost, t... | [
"I'm not sure we have the intelligence or know enough to ever make that distinction, and the loss of any species, a unique thing that may have taken an enormous amount of time to develop seems like something we should try to prevent if we can. "
] |
[
"How do marine mammals survive without fresh water to drink?"
] | [
false
] | null | [
"Marine mammals get their fresh water from the food they eat (ex: fish). ",
"Many dolphins in captivity are \"watered\", which is basically tubing water into their stomachs (painless and trainable), to make sure they get water that may have been lost in frozen fish during processing. Other methods of ensuring hyd... | [
"cats also have extremely efficient kidneys that are capable of getting hydration from saltwater",
"everyone should have a cat."
] | [
"Cats CAN drink salt water.",
"http://en.wikipedia.org/wiki/Cat#Physiology",
"I hate the idea of a democracy of half educated idiots deciding what is or is not a scientific answer via voting.",
"Talk about the blind leading the retarded.",
"*and in case the future is different, thehatman9's correct answer w... |
[
"How much light is there out in deep space?"
] | [
false
] | Science fiction generally shows ships and their hulls reasonably visible no matter where they are in space. How realistic would this be? Say we have a space ship some 2 light years from earth, halfway to alpha centauri, so no where near a major source of light. Is the total 360 degree coverage of stars going to create enough star light to make a hull of a star ship quite visible or are the unlit parts likely to be quite black? And likewise, would a rogue planet or other large object essentially be invisible until you run into it? | [
"create enough star light to make a hull of a star ship quite visible",
"On Earth we have the sun as a good point of reference for what \"bright\" is. In space your reference would need to be a star in your field of view. No matter how dark the hull, if you have no stars in your FOV, you can simply increase your ... | [
"You can't increase the gain without problems. Thermal noise will probably stay the same and make the picture grainy."
] | [
"You could not just increase the gain to make the photo very bright as this would cause a lot of issues due to noise."
] |
[
"How much of the energy that goes into a PC is transformed into heat? How does it compare to a space heater?"
] | [
false
] | I've just asked myself this since my old PC tower does warm up my room when it's on and after all, both a space heater and a computer produce heat by sending electricity through wiring, right? The computer's is just more intricate ... I was also wondering if this would make a computer doing calculations (CERN, folding proteins, cryptocurrency, ...) an efficient replacement for a space heater on either an individual or humanity-wide level. | [
"Pretty much all of it. Some of the energy is converted into sound waves (spinning fans), but when these strike objects and walls, the energy is absorbed and turned into heat as well. Only the sound and light emissions that directly leave the room/house (through windows or doors) don't contribute to heating up the ... | [
"You need quite efficient CPUs/GPUs to recover a large fraction of your electricity cost that way."
] | [
"Essentially all of the energy becomes heat. The space heater will likely be more reliable, and less sensitive to dust. It would also likely have a thermostat, set to shut off the machine at human levels of discomfort rather than computer levels of discomfort. Space heater might be less sensitive to dust and ele... |
[
"Family members are posting on Facebook that there has been no warming in the US since 2005 based on a recent NOAA report, is this accurate? If so, is there some other nuance that this data is not accounting for?"
] | [
false
] | I appreciated your response, thank you. | [
" As ",
"/u/joekercom",
" points out, ",
"the 2005 date is not arbitrary",
". In 2005 NOAA began collecting climate data from a new network of weather stations due to criticisms about the validity of the existing weather station network. The data since 2005, from both the new and the old networks, does not ... | [
"we would expect some years to be above the average and some years below",
"Worth pointing out that basically the same as the arbitrary date thing. The core issue is cherry picking the data."
] | [
"I thought the issue was getting your scientific data from Facebook?"
] |
[
"What would a magnetic field look like in/around a toroidal world?"
] | [
false
] | I've been looking at this , and the author was very curious about what the what they'd look like, but He couldn't be bothered to figure it out. If any of you have any other ideas/facts/statements about this, I'd love to know! | [
"I'm not sure such a question can reasonably be answered. Look at the other spherical planets we know of. Even Venus, relatively the same size as Earth, has practically no magnetic field. Magnetic fields seem to be pretty specific interactions of materials that allow for a spinning metal core that generates such a ... | [
"Yeah so the thing is, the Earth generates its field because a liquid metal core surrounds a solid metal core. And as the Earth turns, that liquid metal sloshes around and undergoes \"convection\" (kind of like how if you heat a pot of water you can see water rise up, go across the top, then sink back down). As tha... | [
"Well I mean hypothetically, If the earth was naturally a torus, and was stable in it's shape at least for a while, Then would the magnetic field cycle radiation down into the center or something? (I love the study of magnetism, but being only 15, I don't know enough about the physics of it.)"
] |
[
"Will endangered animals, if saved from extinction through Human Intervention, face the threat of inbreeding and recessive genes?"
] | [
false
] | null | [
"They already do. Tiger populations in Asia, for instance, are extremely fractured because their territories are separated by human development. As a consequence, problems resulting from inbreeding are very common.",
"There's a lot of species that are still doing fine in terms of numbers but are threatened becaus... | [
"They're stop gap measures at best really. Animals often don't like to use those.",
"There's wildlife bridges all over my country like that, they're virtually unused. One of them is famous for costing millions and being equipped with camera's and sensors to track the way wildlife use the bridge. In five years tim... | [
"There are also efforts to deal with habitat separation; one such effort near Los Angeles will allow mountain lions and other wildlife to mingle across the 101 freeway safely, thus opening the gene pool to a greater source of diversity. ",
"https://inhabitat.com/87m-wildlife-bridge-in-california-will-be-a-haven-f... |
[
"does the amount of tension a wire is under affect its ability to conduct electricity?"
] | [
false
] | If so is it only to a minute extent? | [
"Yes, mechanical strain affects the resistance of a conductor three ways.",
"\nThe resistance of a wire is (rho)L/A, where rho is the conductivity of the metal, L is length and A is cross-sectional area. If you stretch the wire, L goes up, A goes down, and rho goes up because the molecular bonds are being straine... | [
"same material with the same length and area, but not under tension",
"Well, in order to test that you'd have to have two pieces of wire, one longer and thinner than the other; then stretch the shorter one until their dimensions match. But yes, the stretched one would have a slightly greater resistance because of... | [
"Putting something under tension changes it’s length and area. You are comparing the same length of material with the same area (pre tension) but at the length and area you have created post tension. ",
"If you compared something under-tension that had the same length and area under tension as the control not und... |
[
"Why is the black hole photo so big?"
] | [
false
] | [deleted] | [
"The photo is taken using a technique called interferometry. The idea here is that you combine radio waves received on opposite sides of the globe to make an interference pattern - some parts of the waves add together, others cancel out. This tells you that the radio waves travelled a slightly different distance to... | [
"Basically yeah - one of the reasons things got delayed for a while was because there was bad weather in the arctic, I believe"
] | [
"So we're shipping pallets of hard drives around? That's awesome"
] |
[
"In an asymmetric encryption algorithm, can a private key be used to encrypt information with a known outcome to prove that a message came from a trusted source, or would this reveal how to decrypt all messages encrypted with the public key?"
] | [
false
] | null | [
"Yes, and it is done all the time. This is what we call 'signing' a message with a private key - take a plaintext message, take the checksum of that message, and encrypt that checksum - a known outcome - with the private key. Any user can then look up the public key, decrypt the cyphertext, take the checksum of the... | [
"And to address the second part of the question: knowing the original message does not compromise the security of a ",
" cryptographic system, but it can definitely help an attacker crack a bad one."
] | [
"This works with ",
" encryption schemes, for example with RSA. The keys are exchangeable in the sense that there is no difference which one of the keys you declare as the private one and which as the public one. Both can be used to decrypt a message that was encrypted with the other.",
"However, other encrypti... |
[
"Are there any \"surefire\" ways to detect a black hole?"
] | [
false
] | From what little I know about them, it seems that we usually detect them by observing something else interacting with them. Objects being sucked in and releasing x-rays or seeing an object orbit "something invisible". I've heard about work on gravity wave detectors and even they would depend on a black hole interacting with another large mass. Are there any devices we could potentially put on a spaceship that would guarantee it never accidentally travels into a black hole? | [
"Just as an aside, the chances of \"accidentally\" colliding with something in space are very very remote. Space is very big, and collectively, everything in it takes up very little space. Even hitting planet sized objects with our probes takes significant calculations."
] | [
"Your question seems to come from a fundamental misunderstanding about black holes and/or gravity. Black holes are not giant magical death orbs that swallow up everything around them (well, they kind of are...) and nothing can escape. It is no harder to escape a black hole than it would be a star of equal mass.",
... | [
"It is not functionally equivalent, no. Not when you're close to the event horizon. "
] |
[
"Can commercial airlines fly upside down (loops, rolls, etc)?"
] | [
false
] | While flying into Denver today I remembered a strip from Calvin and Hobbes: Calvin--imagining himself a pilot--competes against a rival pilot to land his aircraft first. In one of the final scenes, Calvin "switches on the 'Fasten Seatbelt' light and does a barrel-roll" (or something to the effect). Could this happen IRL on, say, Southwest Airlines flight #4279 with service from Tampa to Denver? Could a pilot roll a plane if necessary? Can a commercial airline perform 'roller coaster-esque' maneuvers such as rolls, loops, etc? (Sorry for a long post! Sorry if repost! Searched and couldn't find anything.) | [
"I can't speak for specifically all commercial planes, but here is a video of as well as interview of test pilot Tex Johnson executing a roll in a Boeing 707,",
"\n",
"https://youtu.be/Ra_khhzuFlE"
] | [
"There's also the most exciting FedEx delivery flight ever, in a DC-10:",
"Tucker pulled the plane into a sudden 15 degree climb, throwing Sanders, Peterson and Calloway out of the cockpit and into the galley. To try to throw Calloway off balance, Tucker then turned the plane into a left roll, almost on its side.... | [
"Background for anyone else since I was very confused:",
"Calloway was a disgruntled pilot who intended to kill Sanders, Peterson, and Tucker (The flight Crew) with the hammer and then crash the plane, making it look like an accident so his family could rake in that sweet 2.5 million dollar life insurance policy.... |
[
"Are lightning bolts fractal?"
] | [
false
] | [deleted] | [
"and a ",
"gif",
" of lightning in slow motion"
] | [
"Picture of a guys ",
"lightning strike scar."
] | [
"Yes",
", lightning is known form patterns consistent with DLA, which are known to be fractals."
] |
[
"What happens if a galaxy is discovered which is estimated to be older than the age of the universe?"
] | [
false
] | null | [
"It means there is an interesting scientific problem to work on!"
] | [
"It may mean the age of the Universe needs to be re-evaluated, or it may mean that there's something fishy about that galaxy which we need to unravel. At this point - and this used to be not the case, up until the past decade or so - there are enough independent directions pointing to the current number for the age... | [
"There is an error in the measurement, or something very interesting is going on. "
] |
[
"What benefits would the addition of a third eye bring?"
] | [
false
] | Thought about this when a bunch of sweat got in one of my eyes while I was pouring a drink. A second eye allows for much better depth perception. Would a third eye just make depth perception even better, have other benefits, or none at all? | [
"Eyes (and cameras) are basically devices for taking in a bunch of light, and sorting it out by angle. If you see something in one eye, you know that it's somewhere along a ray starting at your eye and going out in a particular direction, but you don't know where along the ray it is.",
"Adding a second eye gives ... | [
"Another possible benefit would be greater range of vision, if they eye was placed around back of the head. "
] | [
"Are we brushing aside the liabilities as well? More chances for infections*, needs to be protected under the brow and in a socket, caloric cost, potential epileptic trigger, the added brain circuitry to process more visual stimuli and make sense of it (and the cost of that as well), etc. Who knows, but all these s... |
[
"If Anti-matter annihilates matter, how did anything maintain during the big bang?"
] | [
false
] | Wouldn't everything of cancelled each other out? | [
"That is an excellent question, and one that scientists don't yet have an answer for. It's called the ",
"Baryon Asymmetry",
" problem, and the only way to explain it is to change the rules that we've designed for the way physics governs the universe (the standard model).",
"My favourite explanation is that t... | [
"Let's hope the anti-humans on anti-Earth don't want to visit!",
"Feynman warned us about this. Make sure you ",
"offer to shake hands first",
"."
] | [
"There are problems with all of the proposed explanations, I simply picked the one that seemed the most intuitive."
] |
[
"How does a tunnel boring machine work?"
] | [
false
] | They’re huge and flat so I can’t imagine them drilling. | [
"The short answer is: that flat surface in the front carries smaller cutting disks, and the whole plate is slowly spinning. ",
"There is a video here (",
"https://thekidshouldseethis.com/post/how-does-a-tunnel-boring-machine-work#:~:text=With%20its%20rotating%20cutting%20wheel,press%20the%20machine%20forward%20... | [
"Cool thanks"
] | [
"The link says it's for kids. Is it ok for an adult to see it, too?"
] |
[
"Why are we the only species that \"requires\" toothpaste?"
] | [
false
] | what does ask askscience think about modern dentistry? How much is necessary? Are we screwing up evolution? | [
"We're also the only species that's doubled its own lifespan."
] | [
"We don't require toothpaste. Pry open a monkeys mouth and smell it and then you'll find out why we like it though. (Very much how we don't \"need\" shampoo)"
] | [
"Find a 15 year old dog or cat, and look in its mouth.",
"Chances are, their teeth are a wreck, to the point the animal would have died long ago in the wild.",
"Lots of animals have shortened life spans due in part to bad teeth, and could benefit from better dental care."
] |
[
"When did blood type AB first evolve?"
] | [
false
] | Some people say that AB is the most recent and didn’t occur until the 16th Century when group A populations from Europe and group B populations from Asia began to mix. However, it is known that gibbons and humans both have variants for both A and B blood types, and those variants come from a common ancestor that lived 20 million years ago. Then doesn't it mean blood type AB existed at least before 16th century, while AB is just a mixture of A and B? Which one is correct? What is the scholars' mainstream opinion about it now? | [
"Do you have citations for each of these positions? Better yet, do you have an understanding of the ABO system?",
"Here's a decent review of blood types:",
"https://relevantgenetics.com/the-genetics-of-blood-types/",
"Then you start a basic search engine query and find human AB typing predates the blog rumo... | [
"I am wondering if blood type compatibility is always enough when it comes to donations?",
"No.",
"ABO is the most important compatibility factor, and second is Rh factor (rhesus factor, either positive or negative). Beyond that, there are many other antigen groups that may affect the transfusion. ",
"More on... | [
"This is a great read. I am wondering if blood type compatibility is always enough when it comes to donations? I hear about cases such as organ implants were are different measures taken to ensure compatibility. Is that correct?"
] |
[
"Is there a reason we want more alcohol once we are buzzed?"
] | [
false
] | null | [
"Without going into the neurochemical side of things (because others have somewhat covered it here, and it's exceptionally dirty when it comes to alcohol - multiple neurotransmitter systems are involved and even the metabolites of alcohol probably have their own effects)... there are significant expectancy effects ... | [
"Yeah, definitely. If nearly 1% of your blood is alcohol by weight you're not doing so hot."
] | [
"Yeah, definitely. If nearly 1% of your blood is alcohol by weight you're not doing so hot."
] |
[
"How does the water supply stay sterile after leaving the treatment plant?"
] | [
false
] | Over time wouldn’t the pipes supplying my water build up bacteria inside the pipes? how does the water supply, after it’s left the treatment center, stay sterile and clean for consumption? i live in a city where there’s no apparent issue with drinking water from the tap but if i don’t filter my drinking water, am i inadvertently consuming tons of bacteria by drinking it straight from the tap? Understanding when i wash my hands/take a shower i’m shedding dirt and debris, my drain can get pretty gnarly after a few weeks of not cleaning it, so it makes me sick thinking when the last time the pipe coming to my faucet was cleaned, if ever. | [
"Not tons, but plenty. That is perfectly normal and safe except for very sick people. ",
"Basically the water has low numbers of bacteria in it when it enters the system at the plant (it is not sterile though) and a lot of clever engineering has gone into the network to make sure the quality stays good until the ... | [
"There are some, that's why we use UV too. ",
"Chlorine is also not the same as antibiotics. It's a pretty aggressive oxidizer, there's not that much bacteria can actually do to stop it from destroying their molecules. Enough dosage will always kill. It's kind of like asking why humans have evolved disease resist... | [
"There are some, that's why we use UV too. ",
"Chlorine is also not the same as antibiotics. It's a pretty aggressive oxidizer, there's not that much bacteria can actually do to stop it from destroying their molecules. Enough dosage will always kill. It's kind of like asking why humans have evolved disease resist... |
[
"What's the best way to avoid a tie in this lottery game?"
] | [
false
] | We want to host a lottery game as part of an event. They way it was done before was to ask everyone there to choose 12 numbers between 1 and 50, and then to start randomly selecting numbers between 1 and 50. Anyone who hears one of their numbers said has to sit down, and the winner is the one person left. We did this with about 50 people and it worked fine, but we're now going to do with a larger group (over 100), and are worried it is more likely to be a tie. Would increasing the range or the number of choices improve the probability that there's just one winner? | [
"Interesting problem! Given n=50 players who each select k=12 numbers from 1 to m=50, then playing the game as you describe, we can compute the exact probability p(n,m,k) that there is a unique winner (i.e., no tie) as",
"p[n_, m_, k_] := Sum[\n n C[m - j, k - 1] (C[m, k] - C[m - j + 1, k])^(n - 1),\n {j, 1, ... | [
"Here is an intuitive way to understand this: When the first number is called, on average 12/50 will sit down. When the second number is called, on average 12/49 will sit down (as everyone had their 12 numbers among the 49 not called yet). This leads to a roughly exponential decay initially. With 100 people we reac... | [
"The probability of having a ",
" winner decreases.",
"And although what the top post has is the right way to go about it, i'd expand a little on the intuition behind it: let N be the amount of numbers called out until you have to sit down. N is almost always very small; even N=1 has 24% chance to happen. Howev... |
[
"what could cause a peak at 642nm in an H2 spectrum?"
] | [
false
] | I have a hydrogen gas spectrum tube in a spectrum tube power supply. I have one end of a small bundle of fiber optic strands pointed at the spectrum tube, and the other jammed into the cuvette holder area of a PASCO spectrometer, which is communicating with an iPad via Bluetooth. The 656 nm line is supposed to be there, but I have no idea why I have a peak at 642 nm. What could produce that? | [
"potentially stupid question, but have you checked the line is not there with the light source turned off? I've noticed a few \"lines\" before in a mini-spectrometer that were just hot pixels. \nOther than that, there a number of lines close to that from regular room lights.."
] | [
"The value in the source you cite is based on a diagram where n=2 is 3.44 eV below ionization (instead of 3.4) and n=3 is 1.5 eV below ionization (instead of 1.511), meaning that their red photon has 0.051 eV more energy than it should, which is an extra 2.7%. That accounts for why that source states a value of 642... | [
"Is caused by the hydrogen as well.... \nEnergy transition from lvl3 to lvl 2.",
"See:\n",
"https://www.siyavula.com/read/science/grade-12/optical-phenomena-and-properties-of-matter/12-optical-phenomena-and-properties-of-matter-03"
] |
[
"What goes down in the body after a hit to the testicles?"
] | [
false
] | null | [
"Hi GoAwayAsYouAre thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the ... | [
"Human Body"
] | [
"'Human Body'"
] |
[
"Most \"genetically distant\" human population?"
] | [
false
] | Is there one or several human populations that stick out by being significantly different, genetically, from most other human populations? Not just y-haplogroups or whatever but throughout the genome? Is there, for example, a significant difference between the DNA of genetically isolated populations like the Khoisan, the Andamanese and the the Tasmanian Aboriginals, and other less isolated populations? Edit: does anybody know of any data on the genetic distance of the Andamanese, specifically, to other populations? | [
"There are genetic differences among all populations, throughout the genome. These correspond nicely to archaeological evidence about human migrations: every time a subset of a population migrates to a new place, it carries only a subset of the population's genetic diversity. This is called a genetic bottleneck. So... | [
"Here's another link you might like, one of the coolest things I've ever found on reddit:",
"An interactive map of 160,000 years of human migration in 3 minutes ",
"EDIT",
"\nBachwasbaroque just provided a ",
"very recent article",
" which basically seems to invalidate the claim that the folks who left Af... | [
"I submitted an article about this two years ago: ",
"\"The three primary genetic divisions of humanity are the Hadzabe, the Ju|'hoansi, and everyone else.\"",
"These two African peoples, despite both speaking a click language, are more genetically dissimilar from each other than any other two populations on Ea... |
[
"How do surgeons attach a donated piece of liver to a patient's circulatory system when it's \"cut out\" from a living donor?"
] | [
false
] | null | [
"Basically, they keep the vessels of the donated piece intact and just sew them to the recipient's vessels. You can see a representation of these vessels at the link. \n",
"https://hospital.uillinois.edu/Images/IGX/LIVERdonorTransplant.jpg"
] | [
"I believe their liver will regenerate with new vasculature. They won't have as many large diameter vessels as they did before, but the new small vasculature will find a way to regenerate and make connections with the branches of the portal vein, hepatic artery, and hepatic vein that they have left over. "
] | [
"Interesting! Thanks! :) But won't the donor need those when the liver regenerates?"
] |
[
"Are there any species that, if went extinct, won't upset the ecological balance?"
] | [
false
] | It is considered vital for all species of plants and animals to survive, so as to maintain ecological balance. However, are there any species of animals/insects that can go extinct without having a negative impact on the ecosystem. I think mosquitoes would be one, and also house-flies. They seem to serve no purpose at all. | [
"It's funny you mention mosquitoes, because Nature published an article on exactly this topic. They concluded that if mosquitoes went extinct then there would only be minor disruption while certain insectivores adjust their diets. Some birds, spiders, and fish would have some trouble initially, but they would proba... | [
"I'm very leery of the SA analysis. Not for tropical environments, mind you, but for arctic ones.",
"In the arctic, the food chain is very short with limited redundancy. Arctic mosquitoes form clouds there, and are a force of nature to contend with. They are almost more part of the weather than of the fauna.",
... | [
"Sure there are. Consider the ",
"Tiburon mariposa lily",
", which I've seen in person. They only bloom for a few weeks a year, there are only a couple thousand of them, and their global range consists of a single hill. ",
"It would be sad if it went extinct, but I suspect any ecological impact would be too s... |
[
"Tim Ferris just posted this method of draining one's sinuses - is there any biological basis for it?"
] | [
false
] | From : Is there any biological basis for this? I'm normally a complete skeptic, but Tim has prided himself on being a bit of a body hacker. | [
"What does he think sinuses are?"
] | [
"Yes, it jostles the vomer bone and can get congested mucous moving again. I've been doing it for the last few years and when I'm really stuffed up it does help a little. ",
"Another trick is to think about a food that makes your mouth water. If you can trick your body into thinking it's hungry enough that the mo... | [
"I make no assertions either way on the issue, but here is a perfect opportunity to objectively judge one of his assertions rather than ambiguously question his character."
] |
[
"(Quantum Physics) Can we measure matter and energy of atomic and subatomic particles in 0 gravity? If so what has it proven?"
] | [
false
] | [deleted] | [
"What do you mean by \"zero gravity\". The effect of gravity in any quantum mechanical experiment will be negligible. However, in principle if one managed taking a coherent stream of particles, separating them into two tracks at different heights and then recombining them one would expect an interference effect d... | [
"Ah, the experiment designed to test the Santa effect. Never before have we been able to mathematically describes Santa's electron spin resonance in trips both up the chimney and down the chimney. "
] | [
"There was an experiment a few years ago that launched a Bose-Einstein condensate from a catapult up a chimney and back down, so that the gas could expand isotropically without the influence of gravity. You can read the results here: ",
"http://arxiv.org/pdf/1301.5883.pdf"
] |
[
"If an object is fired down at the Earth from a reasonable height at a speed greater than terminal velocity, will it slow down as it descends?"
] | [
false
] | null | [
"Yes.",
"Consider the Space Shuttle.",
"It would enter the atmosphere at great speed and as it passed through the atmosphere it would slow down.",
"Given enough time the speed of a falling object will settle on its terminal velocity (which is dependent on a number of factors). ",
"Also be aware terminal ve... | [
"No it doesn't. If something is exceeding its terminal velocity, and it doesn't break apart, it will slow down. ",
"Terminal velocity factors in weight and surface area. "
] | [
"One way to think about this is that terminal velocity is reached when the air resistance and gravitational forces balance. The air resistance is greater the faster the object is moving.",
"If the object is moving downwards slower than terminal velocity, it means the gravitational force is greater in size than a... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.