title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why do antipsychotics have so many undesirable side effects?"
] | [
false
] | [deleted] | [
"Well there are two major classes of antipsychotics. Both work similarly, but have significant differences that account for different side effects. ",
"The first group of antipsychotics are now called the \"typical\" antipsychotics and started coming out in the 50s. Drugs in this class include the phenothiazine a... | [
"Glad to help. Its a very interesting topic; especially when considering how little is really understood about the etiology behind the disorders treated by these medications. "
] | [
"Glad to help. Its a very interesting topic; especially when considering how little is really understood about the etiology behind the disorders treated by these medications. "
] |
[
"Did LIGO get incredibly lucky with two black holes colliding or are these fairly frequent?"
] | [
false
] | Also, Did we know this was going to happen beforehand? I understand how LIGO detected the gravity waves but how did we detect the merger in the first place? | [
"We don't know. One of the things we will learn from the LIGO/VIRGO collaboration is how often such events occur.",
"Edit:To answer the other part of the question, no, we didn't know this was going to happen. The detector is just left on and running (the observing run that started in September went until Januar... | [
"LIGO completed an upgrade in summer 2015, so they were observing with a new and improved sensitivity. The upgrade is what made the signal detectable, so it's not a complete accident -- but until we know the rate for such events, we won't know how lucky they were.",
"There may be other events in the data LIGO/VIR... | [
"Interesting...an incredible coincidence, though, isn't it, that LIGO detected this so soon after startup, and yet hasn't detected anything since?",
"Or is it just that the data from the rest of the observing run hasn't been analysed yet?"
] |
[
"Do other animal species have an eye colour diversity similar to humans'?"
] | [
false
] | And if not, what made humans develop such genes? | [
"I don't know about eyes specifically, but differences in coloring (or indeed expression of individual traits) of any external body part within a species is just part of the normal genetic diversity. Just look at the different color schemes in horses (even within a single breed). So if this can be true for hair and... | [
"Cats do, they also can change their eye colour as they age.\nKittens normally have blue eyes and change with time"
] | [
"Just as an example, you can see a number of different eye colors for dogs in this link:\n",
"http://www.doggenetics.co.uk/eyes.html"
] |
[
"Why didn't whole households die of consumption?"
] | [
false
] | In movies and old books, people are often shown with this very long, protracted illness. They're always coughing, and then one day they cough into a white handkerchief and it's stained with blood and you know they're a goner. But you never see the people they live with get sick or even appear to be concerned about cont... | [
"That's tuberculosis and not everybody that gets it, becomes sick, symptomatic and dies of it. I, for example, test positive for tb since I got it while doing clinical practice in an ER as an EMT. This is normal. TB isn't a death sentence. Only when it is no longer contained and controlled by your immune system, is... | [
"Whole families ",
" routinely die of consumption, but those families were not the ones who had books written about them; they were the vast hordes of desperately poor, crowded together and living in squalor unimaginable in today's Western world.",
"In 1838 and 1839 in England between a quarter and a third of t... | [
"Consumption is generally an old timey word for tuberculosis. They just assumed it was non-transmissable because of its portrayals in movies"
] |
[
"How to measure hardness of diamonds?"
] | [
false
] | [deleted] | [
"But how does one determine the hardness of a diamond?\nDiamond is the reference standard. Whatever scale you make, it defines the top, until a harder material becomes widely available. \"hardness\" only makes sense comparing one material to another, so something will always define the maximum.",
"Here's a lin... | [
"The Mohs scale for hardness was created as a qualitative scale. Diamond, being the hardest material, is given the highest hardness value, but that value is unitless and has no real meaning. It just says that it has ability to scratch everything with a lower number."
] | [
"Diamond is ",
"not the hardest substance",
". Several other compounds are harder (one being a polymorph of diamond). Here's a description of ",
"hardness testing methods",
"."
] |
[
"Does breaking the sound barrier cause the speed of a plane to change?"
] | [
false
] | [deleted] | [
"We have to deal with something referred to as the Mach drag rise, or the ",
"Drag Divergence Mach Number",
". At lower speeds, drag increases with the square of velocity (D=1/2 * rho * V",
" * S * Cd). As you get closer to Mach 1, it increases at a faster rate than that. How much more depends on the exact sh... | [
"Aerospace engineer here. ",
"The sound barrier is not called a barrier for nothing, in the early attempts of achieving supersonic fight the surviving pilots often referred to the experience as hitting a wall. ",
"A plane matches the speed of sound at Mach (M) number of 1 , though the region of about 0.8 < M <1... | [
"Please elaborate if the dipsy-doodle consists of something more elaborate than gravity-assisted acceleration, as that seems too awesome a name for me to only know a partial definition."
] |
[
"How much does the resting/basal metabolic rate vary between individuals with similar body composition and weight?"
] | [
false
] | It is not uncommon to hear people make claims about different metabolisms in different people, but are different metabolic rates truly possible? Can people with the amount of body fat, lean muscle mass, weight really have resting/basal metabolic rates that differ by any significant amount (i.e. >=30 kcal/day)? If there... | [
"In short, yes. I can't find the study right now, but basically it took a group of people and had them sit around in an airtight room all day, then measure how CO2 they gave off. From this they calculated the individuals BMR. I believe the two biggest factors that influenced were sex and age (unsurprisingly). The t... | [
"That's too simplified. A 120lb man with 13% body fat and a 120lb woman with 13% body fat will have very different anatomic structures and metabolic rates. Male and female body composition is so much more than just BF% and weight. "
] | [
"Men have much more skeletal muscle which requires ATP, and older people tend to lose much of their neuromusculature. Older women would probably have the lowest BMR with young men having the highest."
] |
[
"Can extreme pressure significantly affect a REDOX reaction?"
] | [
false
] | I enjoy learning about military technology and also chemistry. I had an idea for an anti-tank munition and am curious how effective it would be. Essentially the idea is to use a high explosive shaped charge such as a HESH or HEAT round to push an oxidizer into the tanks armor under insanely high pressure and burn throu... | [
"Chemistry"
] | [
"Chemistry"
] | [
"Theoretically yes. I don't know about your explicit example however.",
"Many redox reactions are reversible (think of rechargeable batteries). This means that reaction, in some cases, is constantly going forward and in reverse. When systems are in equilibrium like that, changing these like pressure and temperatu... |
[
"How much energy are you burning when you shake your legs passively (while sitting at a desk)? Over a period of hours, does it make a caloric difference?"
] | [
false
] | As a drummer, I shake my legs nonstop when I'm studying... Especially this week (finals UGH). edit: since so many people seem to care... I hit the gym 2~3 a week and get plenty of walking/running time every day as an ambulatory student without a car. | [
"While not specifically limited to shaking your legs, people who fidget can burn up to 350 extra calories a day vs. people who don't.",
"\"The most detailed study ever conducted of mundane bodily movements found that obese people tend to be much less fidgety than lean people and spend at least two hours more each... | [
"It's not junk. It's called a pilot study. It demonstrates a principle in exercise physiology and weight management that has been over looked for decades. It's a relatively new area called non-exercise activity thermogenesis (NEAT). "
] | [
"It's not junk. It's called a pilot study. It demonstrates a principle in exercise physiology and weight management that has been over looked for decades. It's a relatively new area called non-exercise activity thermogenesis (NEAT). "
] |
[
"How do we know that the universe is ≈93 billion light years across if the universe is only ≈13.8 billion years old?"
] | [
false
] | null | [
"Sure but also the space behind it expanded, so the current day distance between us and the object it came from is much further than the distance the photon travelled"
] | [
"It didn’t. The universe was expanding the entire time the light was travelling."
] | [
"So the space itself expanded... But wouldn't the light still have to travel through that stretched out space? I'm just having trouble wrapping my mind around it."
] |
[
"Electric or Manual toothbrush the best for cleaning teeth? And which brushing technique is superior?"
] | [
false
] | null | [
"Fourth Year Dentistry student here. Straight from my lectures:",
"Oscillating rotating brushes has superior efficiency in reducing plaque and gingivits over manual brushes (Sicilia 2002)",
"The advantage is a a 7% reduction in plaque and 17% in gingival bleeding (Robinson 2005)",
"However, the actual effecti... | [
"Firstly, I hate to sensationalize but I would URGE everyone to ",
", you can (and I did) do permanent damage by exposing the root of your tooth which will become sensitive for potentially the rest of your life.",
"That said, I never thought I'd find articles on dental hygiene so interesting.",
"http://www.nc... | [
"Firstly, I hate to sensationalize but I would URGE everyone to ",
", you can (and I did) do permanent damage by exposing the root of your tooth which will become sensitive for potentially the rest of your life.",
"That said, I never thought I'd find articles on dental hygiene so interesting.",
"http://www.nc... |
[
"Why do all the planets orbit along the same plane?"
] | [
false
] | Every model I've seen of planets has them orbiting the sun along the same plane like a Frisbee. Same thing for the milky way, is everything along the same plane? | [
"Both the Milky Way and the Solar System were formed from a disc of gas.",
"When gas collapses to form a stellar system or a galaxy, it's extremely unlikely that all of the velocities of the gas will perfectly cancel out, so it's going to have some spin - some angular momentum - to it. You can't easily get rid of... | [
"I will add that this is correct up until the dissipation of the disc. Inside a disc a protoplanet (or any other object) will have a hard time leaving due to exchanges of momentum between the object and the disc acting to dampen perturbations. Once the disc dissipates the restorative nature of the disc is also gone... | [
"Isn’t Pluto’s orbit much more oblong and further tilted from the plane than the rest of the planets? Why is that?"
] |
[
"Is a Collision with Space Dust at Near-Luminal Speed a Catastrophe?"
] | [
false
] | If you were in a spaceship heading .99c and hit some space particulate (say a gram of mass) that was stationary relative to the surrounding space, what would happen to your ship? Would the particulate bounce off? Would the particulate burrow a hole through the ship? Would the particulate destroy the ship? Something... | [
"One gram of matter travelling at 0.99 ",
" would have a kinetic energy of about 500 trillion Joules. On impact with a solid object, most of that energy would be converted into heat, light, and shockwaves through the material. ",
"That's an explosion equivalent to about 100 thousand tons of TNT, or 6 times the ... | [
"It's hard to imagine a spaceship that could survive such a blast.",
"The trick is to not let it hit the spacecraft. As an example let it hit some blast shield well in advance of the spacecraft. It will shoot a hole through that, the collision products then scatter and get distributed over a large range in space.... | [
"One of my favourite sci-fi book series utilises sand as a weapon. Enemy warps into other side of the solar system. Hero fires sand canisters towards them at near-c and detonates them half way to the target. Giant cloud of 6x Hiroshima bombs hits fleet. Nerdy goodness."
] |
[
"Is it possible to measure electric current moving along motor neurons?"
] | [
false
] | I'm a computer engineer by trade, but EE was never my strong suit, so forgive me if I'm completely off here. To me, it seems reasonable that at least, in theory, electrical current in motor neurons (by which I mean - the current passed along your nerves when your brain tells you to flex a muscle; this could also be ina... | [
"Technology for directly measuring the ion currents through axons and across cell membranes has existed in some form since the 1940s. The wikipedia article on ",
"electrophysiology",
" under intracellular recording has a nice survey of the different laboratory techniques.",
"Mostly, these involve sticking a t... | [
"That's more or less what I thought - a quick bit of math shows that at about 4 inches out from the nerve, with a signal on the order of microamps, you get a B field of about 1.5e-12, which gives you about 1.5e-8 gauss. That would require a fairly sensitive sensor to pick up. The commercially available sensors I've... | [
"It is possible, but tricky. You probably recall from your elementary EE that voltage measurements are performed in parallel whereas current measurements are either performed in series or they are performed inductively. We can't put a part of a neuronal membrane in series with our measuring equipment, but we can me... |
[
"If a blend a meal in a blender, how will it affect my body's ability to digest it?"
] | [
false
] | [deleted] | [
"More surface area would allow the enzymes in the digestive tract to break down the food more quickly. Also resulting in quicker uptake of nutrients in the food. But I don't think blending it would make this process significantly quicker than just chewing your food well. "
] | [
"I watched an interesting BBC Documentary called \"10 Things You Need to Know About Losing Weight\" where they tested this. They fed an identical set of ingredients to 2 groups, except that 1 group had the food prepared as a solid meal with glass of water, and the other had it prepared as a soup. Over the next fe... | [
"I dunno about fatter, they'll both absorb the same nutrients but the one with the liquid meal will digest it quicker. Unless the food particles were so large that the enzymes couldn't break them down all the way, which would result in Diarrhea and that person would actually lose more weight. "
] |
[
"How does gravity and the law of conservation of energy and mass work with each other?"
] | [
false
] | I know energy can not appear out of nowhere in a closed system. I want to know where does the kinetic energy of a falling object come from? | [
"Kinetics can be described in terms of a trade-off between potential and kinetic energy. Gravitational potential energy increases as the height of the object increases. As an object falls, the potential energy is turned into kinetic energy."
] | [
"One thing worth mentioning is that potential energy is defined from an arbitrary \"zero-level\" (i'm unsure what it's called in english, I learned physics in Norwegian). We pick the zero-level that suits us best. And as I mentioned in another comment, when working with gravitational potential energy we often use "... | [
"Galilean relativity ",
" classical physics though."
] |
[
"How do we know the size of stars that are thousands of light years away?"
] | [
false
] | Is this picture accurate? If so, how do we measure the sizes and distances of these stars? | [
"Size is usually measured by ",
"interferometry",
". You may know that the angular resolution (i.e. how fine the details are that it can distinguish) depends on it's size, bigger being better. By using two telescopes and interfering the light from them, you can have them act like one much larger telescope. This... | [
"Wait, really?",
"Yup.",
"all stars are point sources",
"Viewed through any normal telescope, they are, with a few exceptions. For example, Betelgeuse is both pretty big and relatively close, so a large enough telescope can resolve it as a disk. The ",
"wikipedia page",
" has some pictures.",
"For the m... | [
"This technique can directly measure the angular diameter of the star.",
"Wait, really? I was told once that \"all stars are point sources,\" but are you saying we can resolve the actual disk of individual stars? I'm inclined to believe you because you're the one with the purple tag, but wow.",
"Relatedly, some... |
[
"What is the neurological explanation for illnesses that cause delusions or hallucinations?"
] | [
false
] | Based on what I have seen from the TED talks by Dr.V. Ramachandran, there is a physical neurological basis for many mental illnesses which previously only had psychological interpretations. Extrapolating from this, do illnesses that cause delusions/hallucinations affect the optic lobes/nerves of the brain directly(cau... | [
"Thanks, But what I was looking for was ",
"1.Do we see or hear things because the disease( or symptoms ) affect a specific part of the brain? \n2. Does the effect happen directly, through synaptic rewiring ( physical breaking and/ or remaking of connections, or indirectly, through imbalance in neurotramsmitters,... | [
"Do we see or hear things because the disease( or symptoms ) affect a specific part of the brain?",
"Yes! We can see this with seizures and neurodegenerative disorders as well. The temporal lobe seems particularly involved, because both temporal lobe epilepsy and frontotemporal dementia are associated with halluc... | [
"The body requires a proper temperature, chemical composition, and believe it or not a proper PRESSURE to work efficiently. Anytime you offset one of those you easily change the rate at which chemical reactions take place, especially in the brain. It's not the illness itself causing the hallucinations (outside of p... |
[
"How do water utilities pressurize pipes over great distances?"
] | [
false
] | How does a water company distribute water in a city? How do they handle surges in customer use? | [
"I work as an engineer modelling water distribution systems for major utilities. The basic components of water utilities, or sometimes private water companies (these are less common) are the following:",
"Water systems are designed to meet \"peak flow\" conditions, and/or fire flow conditions. Historical data is ... | [
"Yes. Typically they will use pumps, but those pumps are not rated to pump enough water to meet demand during peak usage. This way, they slowly fill the water tanks over the course of a day, and the tank can ensure that there's enough water when the demand is at its peak. It's more cost effective to buy a smaller p... | [
"Pumping stations. Lots and lots of pumping stations. Electrical power, with back up (frequently diesel) generators."
] |
[
"Physics question regarding invariance, energy and relativistic motion."
] | [
false
] | Background: I initially asked my teacher the question: "Is energy an invariant property?" That is, will mass "a" have energy "b" Joules regardless of where I observe it from. To this, he replied yes. Now, consider mass x (100kg) is moving through a vacum in a straight line at a constant speed of 1x10 m/s, parallel to ... | [
"That is, will mass \"a\" have energy \"b\" Joules regardless of where I observe it from. To this, he replied yes.",
"He was wrong. Even in Newtonian physics this isn't true; if you are stationary relative to the mass, it has only potential energy. If you're moving relative to the mass (equivalently the mass is m... | [
"Hmm, okay thank you. I wasn't aware about your first paragraph. That clears things up. So what's happening here with respect to mass x, z and point y?"
] | [
"I'm not sure what you mean.",
"The objects have masses of 100 kg. Relative to object z, object x has momentum",
"p = 0",
"and energy",
"E = mc",
" = 8.988 x 10",
" J.",
"Relative to point y, object x has momentum",
"p = 1.061 x 10",
" J s/m",
"and energy ",
"E = 9.534 x 10",
" J.",
"If yo... |
[
"Why have some plants evolved to be spicy?"
] | [
false
] | Is it a defense mechanism like poison? Why have humans developed a taste for it, have we seen animals enjoy spicy things too or do they avoid it? | [
"Spicy foods are most commonly foods that activate specific receptors (mostly TRPs of the vanilloid family) of pain stimulating nerve fibers, so called nociceptors. What that means is that they cause a pain response in most animals that would eat them or even come in contact (ever tried rubbing chili or any other c... | [
"What that means is that they cause a pain response in most animals that would eat them",
"This does not extend to birds. Therefore, mammals, which would grind up the seeds of the fruit, are deterred, but birds, through which seeds are more likely to pass through unharmed, are not, allowing the seeds to be disper... | [
"Is it a defense mechanism like poison?",
"Of sorts. Capsaicin, the chemical that makes foods spicy, is an adaptation that favored one particular dispersal mechanism (birds, who have no response to the chemical) vs another (mammals). Capsaicin also has antifungal qualities that could be helpful to the reproductio... |
[
"Why have we sent so many probes to Mars, yet Venus gets none?"
] | [
false
] | Why do we send so many probes to Mars, yet Venus gets none? I think that Venus has alot to teach us about our own planet. Sure Mars is a better target if we want to have a permanent presence on a planet(s surface). Venus has a large and complex atmosphere that warrants more investigation. | [
"Venus is a bit harder to get to, and probes have to be built tougher to survive there.",
"\"Slowing down\" isn't free in space, so going \"downhill\" towards the Sun can take a lot of energy. We're orbiting the Sun at 30 km/s. To escape the Sun, we only need to go at 44 km/s. So you can go to any outer planet in... | [
"Getting to Mercury is hard, but Venus is very similar to Mars. For a direct Hohmann transfer to Venus you just ~2.5 km/s relative to Earth, and you arrive with ~2.7 km/s relative to Venus. For Mars you need ~2.9 km/s when leaving and arrive with ~2.6 km/s. I used circular planet orbits here, the actual numbers dep... | [
"Venus gets none",
"What do you mean? ",
"https://en.wikipedia.org/wiki/List_of_missions_to_Venus",
"Mars gets more attention simply because it's a better target for manned exploration and because we can set rovers and landers there, and many missions are done in tandem, where orbiter and lander are sent toge... |
[
"Theoretically, on average, how rapidly can you get re-sick after getting sick, assuming you were constantly exposed to the virus in question?"
] | [
false
] | I know that each person has immune systems that work differently, but I'm curious about the average amount of time someone's immune system will prevent recurring diseases of the same kind and what controls that. I'm concerned with both the cold and the flu; I got sick once a year before this semester, and this semester... | [
"This could end up being a long answer, so I am going to try to keep it as short as possible.",
"In general, when you are exposed to a virus or bacteria and mount an immune response, your immune system \"remembers\" that virus or bacteria and can respond to it immediately when you are re-exposed to keep you from ... | [
"well Shingles is an adult reaction to being exposed to chicken pox in your youth."
] | [
"actually chicken pox is a little different.",
"yes, your body does have \"memory\" of chicken pox. but in actuality, if you had the chicken pox as a kid, your body still has the virus. our immune systems are not capable of eliminating that virus through natural infection. instead, our immune systems learn how... |
[
"Do we know if there were any mountains bigger than Mt Everest that have since eroded?"
] | [
false
] | null | [
"The current \"largest\" mountain depends greatly on your definition of \"large\". ",
"If it is maximal summit altitude above mean sea level, then Mt Everest at 8850 m wins, hands down. But the base of Everest on the Himalayan plateau lies at about 4700 m, making its local vertical rise a modest 4100 m.",
"I... | [
"There have been many large mountian ranges throughout earth's history that have since eroded. Without going into specifics of individual mountian ranges, there probably hasn't been a mountian significantly larger than Mt Everest. Maybe a bit larger, but there couldn't have been a mountian say 5 times the size of E... | [
"I think it's just wrong.",
"Are you basing this on any further research than when you got some incomplete answers or misunderstood answers that were given to you? Or is this just an assumption? ",
"Why would it make a difference that some of that is under water? It's all weight on the tectonic plates.",
"Alt... |
[
"Is it possible to image extrasolar bodies directly?"
] | [
false
] | The methods for detecting exoplanets and the like, as far as I know, are rather indirect, involving measuring properties of stars like wobble and luminosity. Could you ever take a picture of such a planet, and if so, is there some sort of "maximum resolution" to what you could achieve? Or is there so little light reach... | [
"We have images of planets around other stars, but they are not resolved - we can't see any detail of the surface, the planets just look like little points of light. Here are some of the images of extra-solar planets we have: ",
"Fomalhaut b",
"Fomalhaut b moving",
"HR 8799",
"They are too small on the sky ... | [
"A constellation of space telescopes would be necessary for that to be practical. Using interferometry it's possible for an array to obtain a resolution similar to that of a single telescope the same size as the array. The problem is, the telescopes must maintain very precise distances from each other, to the order... | [
"How big would a telescope (let's say, in space) have to be to obtain a usable image of the closest/biggest known exoplanet? For usable, say we want to know whether this exoplanet has continents or a big red spot."
] |
[
"Is there a specific event that triggered our evolution to “modern humans” ?"
] | [
false
] | null | [
"I guess one main hypothesis for the exact question, is consuming predictable high density resources as source of food. So possibly seashore fishing. This led to defending or controlling sites. It also benefitted a lot from complex group activity. And society needed to develop ways to avoid devastating fights."
] | [
"My understanding is that 50 million years ago the sub continent of India crashed into Asia, setting off a change in climate. As the climate cooled, the vegetation in Africa changed. Apes had to find food on the ground instead of in trees. Astralopithecus africanus adapted to walking on land as well as climbing in ... | [
"We (or possibly earlier hominins) invented cooking while still in Africa, and anyway long before the last glacial period, and probably even the one before that."
] |
[
"AskScience AMA Series: I'm /u/OrbitalPete, a volcanologist who works on explosive eruptions, earthquakes, and underwater currents. Ask Me Anything!"
] | [
false
] | is a volcanologist based at a university in the UK. He got his PhD in 2010, and has since worked in several countries developing new lab techniques, experiments, and computer models. He specialises in using flume experiments to explore the behaviour of pyroclastic density currents from explosive eruptions, but has also... | [
"Yellowstone is the one everyone likes talking about, but to be honest the press just like getting wound up abaout it.",
"Yes, it's a massive volcano with the potential to do lots of damage. However, it's not showing anything about it that hints there's anything like the volume of eruptable magma that we should b... | [
"Are there any new or troubling signs surrounding the Yellowstone Caldera? How prepared are we to deal with an event of that scope?"
] | [
"Well, Mt Vesuvius is much like any other straovolcano; it has a plumbing system which has a magma reservoir, and when the pressure in that magma reservoir overcomes the confining pressure an eruption occurs.",
"The problem with Vesuvius - as with any stratovolcano - is that once you've triggered an eruption the ... |
[
"What are the correlations between finger length and intelligence?"
] | [
false
] | null | [
"None is known"
] | [
"Are there any visible body parts that are correlated with intelligence?",
"What about big heads or big foreheads even?"
] | [
"Nope"
] |
[
"What causes earthquakes in the centre of a tectonic plate?"
] | [
false
] | Melbourne recently was hit with a 5.3 magnitude earthquake, but Australia isn't on any fault line. How did this happen? | [
"The earth is cut by literally millions (actually, probably billions) of faults. Some are large, some are very small. They key thing is that they form when rocks are subjected to stress and fail in a brittle way. Usually in the top 10km of crust.",
"Certainly there is a very high concentration of faults around te... | [
"OrbitalPete covered everything, just thought I would some other interesting information relating to this.",
"As has been said, there are many, many faults and dykes everywhere in crust of the Earth, some active now, others not. OrbitalPete mentioned fracking and dam construction as sources as human induced seis... | [
"Thanks!"
] |
[
"If a nuclear bomb went off in Boston harbor could scientists tell after the fact who had manufactured it, do they leave distinct radioactive signatures?"
] | [
false
] | Asking for a friend | [
"Watched Sum of All Fears last night?",
"You might want to look into the Monitoring Capabilities of the Comprehensive Test Ban Treaty (CTBT). You can read a bit about it here:",
"https://www.nap.edu/read/10471/chapter/5",
"Basically, radiochemical analysis can tell you information about the bomb design and t... | [
"So in the case of the movie, we would probably have the data to determine the specific manufacturing facility, since it was one of our own. "
] | [
"Yes, as far as I know, the scene seems pretty accurate, with them having a set of \"signatures\" of relative abundances of impurities and isotopes associated with each manufacturing facility within the US, and then checking against them."
] |
[
"How distantly (genetically speaking) are we related to the mitochondria in our cells?"
] | [
false
] | I know technically our mitochondrial DNA is our DNA. But if we were to look at our Nucleus and mitochondria as two different species how distantly related would we say they are? Additionally same question for plants and their chloroplasts. | [
"There's been a lot of translocation events, and a lot of mitochondrial genes are not within \"our genome,\" rather than remaining on mitochondrial plasmid DNA. Mitochondria were (most likely) single cell organisms (prokaryotes) that were endocytosed and remained viable inside old old old eukaryotic cells (endosymb... | [
"The genes found in the DNA of our mitochondria are much more closely related to the ancestral prokaryote from which mitochondria are derived than they are to our own genes. However of the estimated 2000-5000 proteins found in mitochondria only 16 are actually coded for by the mitochondrial genome. The rest are cod... | [
"Now that you mention the translocation of the genes it makes total sense. Im still kinda bumbed out though I was looking forward to tell all my friends that they are closer related to that tree over there than they are to the mitochondria in their cells. I guess I still could but it's just not the same. "
] |
[
"After a amputation, how does the newly generated tissue utlimately know to grow back in proportionate size to the body ?"
] | [
false
] | In animals, how is it that after a amputation, newly generated tissue almost always grow back to it's anatomically correct size by itself?? EDIT:SPELLING | [
"OP may be talking about animals that naturally regenerate. E.g. a lizard loses its tail, how does that lizard's body know to grow back that tail the same way?",
"To apply the subject to humans, I suppose one could ask how children who lose their fingertips know how to regenerate that properly.",
"Link for thos... | [
"I'm going to try and answer that question with two separate answers.",
"In a developing organisms (such as yourself) it's important to distinguish the difference between your mouth and your asshole, so you don't end up talking out of your ass. This process is called gastrulation, and the formation of the archent... | [
"Are you asking about humans?",
"Nothing grows back. The wound edges are sutured and heal like any other wound.",
"If you're referring to salamanders and such, you might want to rephrase your question a bit."
] |
[
"Why is Tylenol dosed by weight for children, but not adults?"
] | [
false
] | I'm 6 feet 4 inches and 220 pounds. Why is my tylenol dose the same as for a 110 pound woman? | [
"You're at a national park and are trying to pick which hiking trail to walk on. They all have stupid names though because a biochemist named them. There's the \"glutathione\" trail - a pleasant meander around a picnic table that then leads to a starbucks, and the \"CYP2E1\" trail - a death march that involves cros... | [
"Also, they're serious about not drinking alcohol while taking Tylenol. The combination can put you in the hospital very fast.",
"This is a very common misconception, even among health-care providers for some reason. Acute intoxication with alcohol is actually hepatoprotective for acetaminophen toxicity. The brie... | [
"Both Tylenol and Aspirin can be extremely toxic. It's actually very common to see overdoses in the ER from them. When I worked in the chemistry lab at a hospital, they were on our urine drug screen along with the \"hardcore\" drugs people usually think of people overdosing on (i.e. heroin). I saw more screens posi... |
[
"Are the occurrences of sinkholes happening more often or are they just being reported on more?"
] | [
false
] | I've noticed more sinkholes on the news in the past while and was wondering is this due to more reporting by the media or will the world eventually swallow us all?? | [
"Sinkholes form in a couple different ways. The ",
"really impressive ones",
" form in sedimentary rocks, like limestone. They are pretty common in places like Kentucky or Florida. They are an effect of ",
"karst processes.",
" Basically groundwater dissolves some of the sedimentary rock and leaves voids. T... | [
"I'm not familiar with the current problems in Florida regarding sinkholes but if what you say is true then it's certainly possible. You're dealing with a geologic environment that is already predisposed to having sinkholes since the majority of Florida (if not all) is sitting on limestone. If massive dewatering ... | [
"I was under the impression that Florida, my home state, has been experiencing more sinkholes in recent years due to depletion of the aquifer caused by heavy development. Can you speak to how accurate that notion is?"
] |
[
"Does color play a vital role in 3D movies? Can a completely color blind person see a 3D movie wearing the classic 3D glasses and notice the difference?"
] | [
false
] | null | [
"Glasses with two colors: If the color blind person's eyes/brain are capable of perceiving light of the respective hue (and of course only the respective eye needs to be able to, not both of them), then they will see the 3D effect.",
"Glasses with polarization filters: Yes all the way.",
"Glasses with two displ... | [
"by squinting one eye (or using special glasses) during scenes where the camera moves horizontally, you can see a 3d effect?",
"Yes. ",
"https://en.wikipedia.org/wiki/Pulfrich_effect",
"The darker image arrives later in your brain's image processing, so ultimately you see two different images simultaneously w... | [
"Glasses with one bright and one dark filter for a movie that plays with horizontal parallax scrolling (Can also be a scene in a normal movie, e.g. camera flying around sideways in \"Lord of the Rings - The Fellowship of the Ring\". You can simulate these glasses at any time by just squinting one eye, I do this oft... |
[
"Is there a reason all the planets orbit the sun in approximately the same plane and direction?"
] | [
false
] | null | [
"Yes. Conservation of angular momentum. Our solar system started out as a rotating gas cloud. Over time, this cloud collapsed and denser regions formed the sun and the planets. But due to conservation of angular momentum, the rotation had to remain, which means that the solar system as a whole rotates around the sa... | [
"An interesting side note: Venus rotates on its axis in the opposite direction from all other planets which astronomers believe means it was hit by something big early in its formation. "
] | [
"I like how most eventualities in the solar system end with \"but the sun will have expanded to a red giant and swallowed everything by then\"."
] |
[
"Doesn't Element 113 already exist?"
] | [
false
] | I am not very informed about chemistry so this might be a really stupid question but on the Periodic Table isn't the element with 113 protons called Ununtrium? Can any chemists out there tell me how the discovery a few days ago is new? What am I missing about how the Periodic Table works and what was discovered? | [
"Those funny names near the end of the periodic table are standardized placeholders for undiscovered/unnamed elements. The recent work in Japan seemed to clarify the decay chain for element 113. It might pave the way to naming rights for the element."
] | [
"Those funny names near the end of the periodic table are standardized placeholders ",
"They also happen to be Latin for that number of the element, ",
"um literally means ",
"."
] | [
"In a more philosophical vein, it is almost definite that it already exists. We just haven't documented it's existence yet."
] |
[
"What does it mean that we are 70% water?"
] | [
false
] | I guess I am curious as to where this water is located in our body and why does it make up so much of us? Also, which animals are made up of the highest percentage of water and which ones are the lowest? Then, why are humans 70% as opposed to other animals? I know this is technically more than one question but I'm real... | [
"Cytosols of cells, interstitial spaces, blood, etc. The water is literally everywhere in the body. It is the matter in which our important life-sustaining materials are dissolved. Without the water, our enzymes, proteins, and sugars would have nowhere to exist. The would just be inactive solid matter. "
] | [
"Whoa, this is insanely in-depth. Thank you so much. I really appreciate it. This actually helps me out a lot."
] | [
"We're mostly a solution. A gellylike substans with dispersed particles in it. The reason we appear solid is because we're made of a lot of small \"solid\" containers with the solution in it.. For example a filled thermo flask appear very solid, but it's a high% of water.",
"Also, we're only 60% of water"
] |
[
"How do computers find the prime factorization of REALLY big numbers?"
] | [
false
] | So I'm writing a computer program in c++ that uses a function that theoretically can find the prime factorization of any number. And so far with testing, my program (45 lines long by the way), works the way it should. However I am inhibited from checking numbers larger than 9223372036854775807 due to the fact that ther... | [
"What I think you need is called \"arbitrary-precision arithmetic\". There are many implementations of this in C++, a mature one is ",
"GMP",
". It has types that allow you to perform operations on numbers of any size. ",
"On computers, all numbers are represented as series of bits. ",
"int",
", is (usual... | [
"9223372036854775807",
"This is 2",
"-1, i.e. the largest signed integer you can fit in a 64 bit register.",
"Your processor won't do more than that. We don't have 128 bit processors yet and, beyond a few special cases like yours, there would be no meaningful advantage in general computing if we had them.",
... | [
"In addition to the problem of \"representing large numbers\", which is solved by GMP or any other \"bignum\" library, there is the separate problem of \"factorizing large numbers\". Even if you ",
" handle arbitrarily long numbers, the naive method (trying all primes, in order) is usually ",
" - by which I mea... |
[
"What happens if a gust of wind exceeds the speed of sound?"
] | [
false
] | does the wind breaking the sound barrier make a sonic boom, or what? | [
"It leads to a ",
"shock front",
"."
] | [
"Har har!"
] | [
"It's impossible in our environment and environment's it may be possible in, we don't know enough about to accurately determine outcomes and effects."
] |
[
"Has there already been a noticeable decrease in cervical cancers since the widespread introduction of the HPV vaccine?"
] | [
false
] | null | [
"Short answer: Overall yes, for cervical adenocarcinoma, no.",
"Long answer: I would say that the introduction of Pap smear screening and HPV testing is a bigger factor for the decrease in the incidence of cervical cancer since it can reliably detect precancerous lesions such as ASCUS, ASCH, LSIL and HSIL. Of cou... | [
"In Australia, where they introduced the hbv vaccine in 2006, if I remember right, they have a vaccination rate of over 70 %. (All genders). Their pappiloma caused cancers dropped from 22.7% to 1.1%. ",
"The biggest issue they have now is the low participation in screenings, else they would not have new hpv cance... | [
"Thank you for your answer! A further question that your answer raises: what tests are effective at detecting adenocarcinoma if conventional pap smears don't do the job well? And are these something that I should ask for, or would a doctor normally bring it up while doing a conventional pap smear?"
] |
[
"What is the fastest recorded movement of an object on Earth?"
] | [
false
] | [deleted] | [
"Hrm. At a guess, I would say we should look at incoming meteors."
] | [
"Non-microsopic would probably be the Sandia Enhanced Hyper Velocity Launcher at 10 miles per second.",
"http://www.nytimes.com/1994/03/22/science/fastest-gun-on-earth-goals-go-beyond-planet.html?pagewanted=all&src=pm"
] | [
"Yes but OP said non-microscopic objects."
] |
[
"How are rabies vaccines tested on humans?"
] | [
false
] | In my understanding each vaccine, before it enters regular usage, must undergo trials. During trials one group of people gets a vaccine, the other gets placebo, so that we can compare number of infections in each group. I can see how it works with diseases like influenza, COVID or measles. But how it works with rabies?... | [
"As a point of clarification regarding clinical trials, not all clinical trials are conducted with placebo. Many are conducted either vs standard of care, or even without any internal controls and instead compared to historical data. ",
"This is a common misconception that people throw around regarding clinical t... | [
"The rabies vaccine was first developed by Louie Pasteur about 120 years ago. There was no other vaccine or effective treatment for rabies at that time. Medical ethics weren't well developed either. Medical researchers tested drugs on themselves, their families, and strangers who didn't understand what was bein... | [
"/u/x47126g",
" seems to be generally on the right track.",
"Even drugs like aspirin would be unlikely to pass clinical trials today given their stringency. Back in the day there were no rules.",
" (in fact the vaccine was made from an attenuated viral strain from rabbits) according to this article: ",
"htt... |
[
"How big can an island get? (Clarification in description)"
] | [
false
] | Islands are land masses in water. Continents are as well. We don't consider Africa an island. How big would an island have to be to no longer be considered an island? | [
"Well yeah - and that distinction might be usefull in a hypothetical intermediate scenario, but as you say historically it has not been a factor.",
"PS: To us geologists, India ",
" a distinct continent..."
] | [
"There are no clear guidelines. All I can say is the limit will be between Australia and Greenland; Greenland is roughly one third of the area of Australia..."
] | [
"Australia is also on a separate tectonic plate - Greenland is on the North American plate.",
"Of course there's a little bit of post-hoc reasoning here; what was an island versus what was a continent was decided before we knew about plate tectonics - if being on a separate plate was the primary criterion, then M... |
[
"Would spherical wheels (on cars, trucks etc.) provide any benefits? If yes, are they even close to feasible?"
] | [
false
] | [deleted] | [
"There was a time when cars had \"balloon\" tires with weak sidewalls and with the tires much higher in diameter than the rims. The problem was that the tires lacked stability on cornering. Modern tires have stronger sidewalls and lower profiles, which strengthens them for cornering. Spherical tires would have the ... | [
"A sphere will have a smaller contact patch which reduces grip and is not ideal for safety and performance reasons. A sphere might also have more mass which also adversely affects performance. On top of that you've got either an axle which prevents any funky directional movement anyway, or a complicated (heavy and ... | [
"Motorcycle tires have a much rounder cross section than automobile tires, since bikes turn be leaning over, not by turning the front wheel as in a car, with more flat-bottom tires. For a tire designed to stay flat, not lean into a turn, you want more surface area in contact with the road to deliver power from the ... |
[
"What are key differences between a human brain and its closest non-human relative (I think the chimp)?"
] | [
false
] | null | [
"Our brains are more wrinkly, which gives it more surface area for grey matter tissue and we have a larger prefrontal cortex.",
"We can think more abstractly and are much better communicators. Humanities secret sauce is written language that can document things which helps our societies build upon each other. I ... | [
"Well for one thing it's about 3x as big."
] | [
"Our brain is 3 times larger mainly because of the ",
"association cortex.",
" A group of regions that supports such sophisticated cognitive functions as language, self-awareness, and problem solving.",
"The size of the human association cortex is only part of what makes this region unusual in humans. In addi... |
[
"Why do all objects fall at the same acceleration in free fall?"
] | [
false
] | From my understanding, when objects fall under the force of gravity, they all experience a force that causes them to experience the same amount of acceleration. But, the force that acts upon them is different according to their mass. So my question is, how does gravity "know" how much force each object should experienc... | [
"The problem here is that you've plugged in \"g\" for all objects, therefore you've ",
" with the assumption that acceleration due to gravity is same for all objects. The question, though, is asking for the very reason this is the case - that is, they're asking ",
" is there an \"extra force\" for heavier objec... | [
"My response was to get the user I replied to thinking about the flaw in their own argument. The question was rhetorical.",
"Perhaps you meant to reply to them instead of me."
] | [
"You'll find that this is ",
"one of the problems scientists have",
" with treating gravity as a ",
". This is eventually resolved with the ",
"equivalence principle",
", where instead of treating gravity as a ",
", one deals entirely in terms of ",
" - being on Earth is the same as being in an accele... |
[
"What is the pH of NiMH and Lithium-ion batteries?"
] | [
false
] | Looking at the Safety Data Sheets of NiMH and Lithium-ion batteries they say "not applicable" when asked about pH. Both batteries are bases, and while maybe not soluble in water, should still have a pH that could be calculated (Lead Acid car battery pH 0, Alkaline AA battery pH 11). Can anyone help me finish my battery... | [
"I will have to disagree with dispirited-centrist here. NiMH batteries typically use a KOH solvent, which would produce K+ and OH- ions in solution. And some webpages discussing the battery ",
"mention this",
".",
"So why don't the SDS sheets mention this? Because this is an NiMH ",
". The entire battery is... | [
"Yes, one has to remember that the purpose of the SDS is to show users how to correctly handle a substance / item, or how to deal with accidents -- not to give a full accounting of chemical properties. In light of that, I'm not surprised that the \"pH of a battery\" does not appear on the SDS."
] | [
"Can anyone help me track down a pH for NiMH and Lithium-ion batteries? Miffed Mouse is correct, that they would need to be pH tested using Bronsted-Lowry Acid-Base module using something other than water.\nThe SDS requirement for disclosing pH for lead acid and alkaline batteries is because those can be tested usi... |
[
"When did humans start to cut their hair, and how was it not a problem with the hair getting too long before we had tools to cut it?"
] | [
false
] | Don't think I need to specify anything, the question is in the title. :) | [
"Upvoted for your reproducible and falsifiable experimental method. "
] | [
"I don't know why everybody here is getting down voted but they make great points. Tool use is pretty extensive throughout our history and even before we speciated (some 200,000 years ago). ",
"Oldowan tools",
" were used ~2 million years ago. Meaning, our very earliest ancestors had means of dealing with long ... | [
"Obsidian is a good possibility, to be specific. It holds a ridiculously sharp edge.",
"Source: I just sheared a piece off, it cut the hair on my arm."
] |
[
"The derivative of position is velocity. The derivative of velocity is acceleration. Can you keep going? If so, what do those derivatives mean?"
] | [
false
] | I've been refreshing some mathematics and physics lately, and was wondering about this. | [
"The derivative of acceleration is called the ",
".",
"The derivative of the jerk is called the ",
" or ",
".",
"In an homage to Rice Krispies, the next two derivatives have been termed the ",
" and the ",
".",
"In terms of meaning, I'm not sure what to add other than the jerk is the rate at which a... | [
"An example of jerk would be a rocket that has constant thrust, and whose mass is constantly diminishing (i.e., the fuel is being used)."
] | [
"The derivative of acceleration with respect to time is the ",
"The derivative of jerk with respect to time is the ",
"The derivative of snap with respect to time is the ",
"The derivative of crackle with respect to time is the ",
"The derivative of pop with respect to time is the ",
"The derivative of lo... |
[
"Why do we have phases of matter? Why doesn't matter just become more fluid as temperature increases, instead of sudden changes?"
] | [
false
] | Only in 8th grade, so what I've learned about how energy is probably completely wrong. Sorry if this belongs in chemistry, I wasn't sure which one it belongs in. Please notify me/change it for me if your a mod! :) | [
"The distinction is often as vague are you're suggesting. For example in glasses, there is little distinction between a solid and a liquid - eventually on cooling, molecules have insufficient thermal energy to easily move past each other, and so the sample behaves as a solid. As a guide, one can assume a liquid has... | [
"So here is the simplest example I can think of.",
"Imagine you have two Lego blocks connected to each other that you separate. You try to separate them in the beginning with a minimal amount of force, but then you realize that you need to apply more force. ",
"You keep applying more and more force until you re... | [
"The gooification mentioned above is something getting more and more viscous until it won't move any more. This is what happens to glass as it's cooled down. If you want to try at home, you can heat a jolly rancher up, play with it when it melts, then as it cools it gradually becomes stiffer and stiffer until you c... |
[
"Why is random noise incompressible?"
] | [
false
] | I was looking up whether it is possible to have an incompressible sequence. I came across this post in which people are saying that random noise is incompressible: However, if I came up with a random sequence of numbers I would be able to encode the data in fewer bits by recognising patterns in the data, say multiple ... | [
"To be lossless, a compression function must have at least one output for every input (pigeonhole principle). If the input is taken from a uniformly random set of strings of a given maximum length, the input is already perfectly compressed.",
"For example, say your input is max two bits. You have 7 possible input... | [
"Your new encoding of '1'",
" would take up the spot of a shorter string, that string would then need a new encoding, and because '1'",
" is equally likely as the shorter string, on average your algorithm will produce the same or longer length as output.",
"Compression ",
" work if the input is non-uniforml... | [
"But when you have only a single one or zero, your compression scheme will still have to write whatever the word length of 'n' is for every bit.\nThat makes the file bigger whenever the run is less the word length of 'n'. If you have a run that's bigger than the word length of 'n' can represent, then you need to a... |
[
"Why do African American and Caucasian Americans have different sounding voices?"
] | [
false
] | [deleted] | [
"Nothing genetic. Blacks in the UK for example have either very British accent or Caribbean accents.",
"Case in point ",
"Steven K Amos",
"Might be caltural identification. Look at this thread ",
" native american accent",
"."
] | [
"I believe the OP was referring to pitch."
] | [
"It is all cultural. Language is a learned skill. You could take any child of any race and put them in any culture and watch them develop just like a child of that culture would. (more or less, the child might not be fully accepted because of his or her differences)"
] |
[
"Is it possible to create thrust in a vacuum with just electricity?"
] | [
false
] | As far as I know, the only ways to generate thrust in space is to expend fuel (i.e. liquid oxygen/hydrogen). Would it be possible to generate thrust with just electricity, from solar panels and/or a nuclear reactor? | [
"That's basically a less efficient way of reflecting the light back from a ",
"solar sail"
] | [
"It is possible to use ",
"radiation pressure",
" as a form of propulsion, by using electricity to blast light in one direction, which propels the spaceship (I assume we're talking spaceships here) the other way to conserve momentum. This is generally really low-force though. A megawatt laser would provide abou... | [
"Conservation of momentum!"
] |
[
"Physics debate on Kennedy Assassination"
] | [
false
] | Before you eat me alive, this isn't a conspiracy theory. I'm having a heated debate with my friends about the physics behind the Kennedy Assassination. This is how it's worded online and I can't find a definitive answer one way or another on Google. Please help! "Finally, the headshot. The fact that Kennedy's head jerk... | [
"From the hearings:",
"Excerpts from testimony of Alfred G. Olivier, DVM to Rockefeller Commission, April 18, 1975. Transcript of testimony taken beginning at page 21 of the testimony. Dr. Olivier, (A.) a wound ballistics scientist, is being questioned by Robert Olsen. (Q.)",
"Q. What is your opinion, based upo... | [
"...there's no conceivable way for the head to move towards the direction of the shot.",
"If brain matter is only \"pulled\" or \"dragged\" along with the bullet, then you're correct. But it's possible for fluid dynamics to convert the lateral displacement of brain matter from the bullet (the bullet pushing shit ... | [
"That is correct. The physics here is pretty simple - every reaction has an equal and opposite reaction. The bullet doesn't impart much momentum on impact (which is why people don't fly backwards when shot, and why his head didn't jerk forward). As you have already found out, when the bullet leaves the head, it wil... |
[
"Why is the ocean blue?"
] | [
false
] | I asked myself this question when i was 3 years old, yet why not answering it 21 years later? | [
"When you look at something, the color you see is the color of all the light that ",
" absorbed by that object.",
"Similarly, water looks blue because it tends to absorb all colors of light very well except for blue light. "
] | [
"For more information on this, watch the most recent episode of Cosmos with Neil DeGrasse Tyson - this topic is elaborated and explained very well. "
] | [
"It is, its just so lightly blue its not enough water to notice. Think of it as highly diluted."
] |
[
"If I had a long stick that stretched out light years into space, and I pushed it forwards, would the other end of the stick move forward at the exact same time (assuming we had a way to record that the events happened at the same time)?"
] | [
false
] | null | [
"Please see the FAQ"
] | [
"I don't see my question. If you know it's there, can you please link me?"
] | [
"https://www.reddit.com/r/askscience/wiki/physics/rod_speedoflight"
] |
[
"Will the biodegradable material in our landfills eventually become \"fossil fuels\" after millions of years?"
] | [
false
] | By fossil fuels, I mean hydrocarbon substances similar to the oil we use today. | [
"Kind of in the right circumstances but it would only be a really thin layer in future sediment. There are several reasons why we have so much fossilised organic material from the Carboniferous period. Co2 and temperature where much higher than today leading to the land producing a hell of a lot more bio mass than ... | [
"This isn't what you're asking, really, but we are already covering landfills and capturing methane from them. So we are getting hydrocarbons from them. Incidentally, much of this recovered methane gets steam-reformed into hydrogen for industrial use. "
] | [
"The great structural innovation of the Carboniferous was lignin. Cellulose has been around before land plants.",
"Much of our coal comes from ",
"Lepidodendrons",
", large scaly Dr. Seuss trees that were distantly related to modern club mosses. There were also cycads and ferns, but no flowering plants and am... |
[
"Why are rain clouds grey and normal clouds white if they're both made up of water?"
] | [
false
] | [deleted] | [
"Rain clouds are supersaturated, meaning they contain more water than the air can actually hold. The \"extra\" water falls to the ground as rain. This means there's more water which absorbs more light in a rain cloud than a normal cloud."
] | [
"If you've ever flown through heavy clouds during the day, you'll see that clouds that appear gray from the ground look as fluffy and white as any other cloud from above. This is especially evident when flying past cumulonimbus clouds, since the sunlit side is shiny white, and the shaded side is dark gray."
] | [
"Rain clouds tend to be more densely packed with water, as well as bigger, so less light from the sun can get through. Less light means a darker gray. If you're ever in a plane flying over a rain cloud, they look just like any other cloud at that point because you have the same amount of light on your side (above t... |
[
"What causes accents?"
] | [
false
] | Why do humans from various parts of the worlds have accents? Are our vocal chords different biologically? | [
"I'm sure it's a serious question. I'd like to know if you can you elaborate on why people struggle to hear and recreate the sounds of others, that don't seem difficult to others? For example, what makes the 'L' sound or the 'V' sound hard to recreate for many east Asian people, when intuitively it seems like you c... | [
"They have accents because they speak different languages or dialects. Our vocal chords are not biologically different; it's all about the speech community that we grew up in.",
"If you'd like a more in-depth answer, I would be happy to give it. Perhaps you can elaborate on why you suspected our vocal chords are ... | [
"I'd expect a lot of it would be muscle memory, the more you make a certain sound the easier it is to do. So making a completely new one would be very difficult."
] |
[
"How does Capillary Action work?"
] | [
false
] | A friend of mine was telling me the other day about Capillary action. You stick a tube in water and water goes up the tube, he said it's how plants get water and nutrients around their bodies. However he didn't have a good explanation as to how it works, I thought AskScience might be able to help! | [
"A force ",
" move the water up, though. ",
"So gravity pulls things down. We know that. But with water we have capillary action which offsets gravity. Water is a polar molecule. It has a positively charged end and a negatively charged end. Additionally, it has oxygen bound to hydrogen, which means there ... | [
"...this explanation is absolutely fantastic. Two thumbs up from someone who deals regularly with surface science."
] | [
"Water is polar. It has no net charge, but one side of it is a little bit positive, and the other side negative. This attraction is what drives capillary action... the water is attracted to either a positive or negative charge in the tube, and then more water is attracted to that water, and so on.",
"This is kn... |
[
"Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"Great follow ups. ",
"And on to the new questions!"
] | [
"The nudge would propagate through the rod at the speed of sound in the rod."
] | [
"More of a music specialist than a physics expert:",
"Yes, the piano. It relies on physical weights to balance the keys and reset their positions. It would basically be unplayable in zero G.",
"Most other instruments are perfectly playable in a sound sense in zero-g, but they may be less comfortable to hold bec... |
[
"If we see the sun as yellow, why isn't paper yellow?"
] | [
false
] | I'm guessing that the sun is not yellow... then why does it appear to be yellow? | [
"The sun is actually white but looks yellow through our atmosphere. The atmosphere scatters more blue light than red light. This happens because of the relative size of air particles and wavelength of sunlight and is an example of ",
"Rayleigh scattering",
". ",
"FUN EXPERIMENT: You can perform Rayleigh sca... | [
"First light is an electromagnetic wave, and its color is directly related to its wavelength (though you likely knew this).",
"The sun emits a wide ",
"spectrum of wavelengths",
" with peak intensity as green (linked image via google image slightly oversimplifies the picture by leaving out ",
"peaks and tro... | [
"Well, yes, if the ambient light is green, your white paper will look green. Same for any other color. But I'm not sure whether that's what you're asking.",
"In the other thread, one of the panelists and me discussed another quite likely aspect of your initial question: What if your premise was wrong? What if the... |
[
"How does E. coli spread?"
] | [
false
] | With the recent recall of lettuce in the US/Canada, if someone had purchased produce that had E. coli would nearby produce “get infected”? If one person consumes it can they infect others? How does E. coli spread? | [
"While E. coli is commonly found in the gut of many animals ",
", it also commonly found in the soil. ",
"In most cases it harmless. the guts of animals just provide good conditions for the bacteria to grow.",
"However certain strains. of E. coli produce a toxin called Shiga toxin. In humans, this can cause p... | [
"Very informative, thank you!"
] | [
"E. coli need two things to reproduce; nutrients and water. Since they're microorganisms around five micrometers in length, they don't really need much of either to reproduce. So if you have two vegetables with traces of soil on them, and one of them is infected with E. coli, it is probable that the bacterial can t... |
[
"Hey guys! Two questions about phospholipid bilayers!"
] | [
false
] | null | [
"Cholesterol makes bilayers more rigid and less permeable. So removing cholesterol would lead to increased membrane fluidity and permeability. The greatest quantity of water in a bilayer would be on either side. "
] | [
"Just to clarify to SwappingGames in case,",
"The phospholipids that make up the lipid bilayer have two sides, one charged (hydrophilic) and one fatty (hydrophobic). The layer is formed because all of the hydrophobic parts comes together pointing the hydrophilic part towards the outside and inner part of the cell... | [
"In addition to what yaa..sh said, cholesterol does a few other extremely important things. It has functions in cell signaling and, more importantly, is essential in the clathrin/caveolae endocytosis pathways (Google that if you're not familiar, because it's really important). Also, in extremely cold environments, ... |
[
"What force balances gravity when I spin a belt/cord/rope above my head in a circular motion?"
] | [
false
] | Why does the belt/cord/rope's end remain horizontal despite gravity? | [
"Good question. This is a problem often addressed in a first year mechanics class. It is the tension in the string which balances the force of gravity, and that tension is determined by the string's weight and how fast the string is spinning - spinning faster means more tension, according to the centripetal force l... | [
"The thing at the end of the rope's inertia and the force you are applying to it with your hand at the center of your spinning rope circle. If you let go of the rope, it will just fly off in one direction as per its inertia and fall down as per gravity.",
"You keep pulling it back, preventing it from going where ... | [
"I can't understand.",
"If you let go of the rope, it will just fly off in one direction as per its inertia and fall down as per gravity.",
"correct",
"You keep pulling it back, preventing it from going where it wants to go - flying away and falling down. ",
"How can pulling it back prevent it from falling?... |
[
"Do third trimester babies imprint on the voices of their mother and the people around her while in the womb?"
] | [
false
] | We are having our first baby and my wife has come across all sorts of stuff of varying degrees of usefulness and crazy on the Internet. She has fastened on this idea that our baby can hear her voice and mine an is imprinting on them. I'm skeptical of this because I think the flesh and amniotic fluid would suppress the ... | [
"I think the important fact is that your wife believes it's important, therefore it is now important for you.",
"Methodology: Married for 22 years. "
] | [
"Yes and no. Babies can recognize their mother's voice in the womb, but not the voices of those outside the womb. The evidence for this is based on a few experiments. ",
"Anthony DeCasper and William Fifer from UNC in Greensboro devised an experiment in which newborns were fitted with a special pacifier and he... | [
" I've only been running a five year study but my data also supports this conclusion. "
] |
[
"Many humans have ticklish areas like underarms; in other animals that doesn’t seem to be the case. Is there an evolutionary explanation for why certain animals are ticklish and where?"
] | [
false
] | null | [
"\"Tickling\" in humans is a two part reaction. First there is a physical stimulus that leads to involuntary muscle twitching. The second half of this, again in humans, is a generally a reflexive laugh. Plenty of animals demonstrate the involuntary twitching response but then do not reflex with any analog to \"l... | [
"https://www.medicalnewstoday.com/articles/322100",
"\"Researchers do not know why some people are more ticklish than others. Some speculate that ticklishness might be genetic, but there is no conclusive research to support this theory.",
"Some people may be ticklish on certain parts of the body but not others.... | [
"I’m pretty sure that tickling is a defensive play reflex. We’re ticklish in our vulnerable areas and respond by turning away and laughing, demonstrating the play reflex."
] |
[
"Does special relativity preclude multiple time dimensions?"
] | [
false
] | [deleted] | [
"No, it doesn't. Special relativity admits a simple generalization to p time dimensions and q space dimensions by replacing the Lorentz group with SO(p,q), the group of transformations that preserve the line element:",
"ds",
" = (dt",
" )",
" + ... + (dt",
" )",
" - (dx",
" )",
" - ... - (dx",
" )... | [
"Special relativity does not explicitly rule out extra time dimensions, but there are nevertheless a lot of problems with that idea.",
"To expand on the answer of ",
"/u/rantonais",
", multiple time dimensions change the equations of physics in a highly problematic way. With one time dimension, it is possibl... | [
"I don't think he's saying that at all."
] |
[
"What causes a sun-sneeze?"
] | [
false
] | null | [
"I thought this was BS, this guy is serious!"
] | [
"I thought this was BS, this guy is serious!"
] | [
"It's a reflex. More specifically, the ",
"photic sneeze reflex",
"There are many proposed explanations as to why it happens but we don't know for sure."
] |
[
"Is there anything that is the opposite of depression?"
] | [
false
] | null | [
"Are you referring to depression of mood? If so, then yes, the opposite is mania, which is an unreasonable elevation of mood.",
"The two are often encountered together in bipolar disorder, which used to be referred to as \"manic depression\", as people who have it cycle between these poles.",
"It is actually a ... | [
"Are there any cases where mania is present without the depressive end of the spectrum just like there are plenty of people who are depressed but never manic?"
] | [
"There are people with BP who are closer to unipolar mania, though there is some dissent whether it should be classified as its own disorder, separate from BP.",
"http://www.jad-journal.com/article/S0165-0327(13)00734-9/abstract?cc=y"
] |
[
"How much would it cost to set up a live streaming webcam in space?"
] | [
false
] | Ideally, I would like to send a lot of them out in various directions. Is this reasonable? | [
"How much would it cost to set up a live streaming webcam in space?",
"That's easy to answer -- make up a small prototype with a camera, a transmitter and solar panels. Let's say the entire bundle weighs 20 kilos -- this is a minimal mass for a device like this. Next -- ",
"recent estimates",
" for launching ... | [
"You would also only get signals from the satellite web cam when its in range of your receiver (line of sight). So when its beyond the horizon you wouldnt get any pictures - unless you have another receiver. ",
"The other option being a satellite in a geostationary orbit - the satellite would transmit in microwav... | [
"You would also only get signals from the satellite web cam when its in range of your receiver (line of sight).",
"Yes, true -- every 90 minutes for maybe 15 minutes at best. And that assumes an equatorial orbit, with the receiver on the equator as well. For a typical launch latitude, even less time overall due t... |
[
"Can you carbonate any liquid?"
] | [
false
] | I make my own seltzer at home and to carbonate water you simply pressurize your vessel with CO2 and shake it around until it is "dispersed" throughout the water (A rough way to say it). Would you be able to put in any liquid you wanted and have it act the same way? | [
"It depends on what you define as \"act in the same way.\" Carbon dioxide is going to have a different solubility in every different liquid. The way it interacts with ethanol-water mixtures for example can be very different than mostly pure water (you can find ",
"a lot of numbers",
" if you want). The solub... | [
"It might surprise you that you can carbonate some foods as well!",
"https://www.youtube.com/watch?v=FUyYRwtAqvA"
] | [
"I assume what you mean by act the same way is the taste sensation from seltzer. For that to happen, the CO2 must be not simple dissolved in the liquid, but react to formation carbonic acid CO3H2. Water is just the best solvent/reactant to form CO3H2 from CO2. Any other reaction or source that forms CO3H2 would beh... |
[
"What structure in the human body allows us to sense temperature?"
] | [
false
] | There are plenty of scientific instruments that humans have devised to measure temperature (thermometers, thermistors, infra-red imagers, etc.) but I've asked several medical school student friends of mine what the equivalent structure in, say, a human fingertip is that allows us to perceive temperature; I've not recei... | [
"There are warm and cold ",
"thermoreceptors",
" that are made of nerve fibers which fire at different rates depending if the environment in warm or cool. ",
"Internal temperature control has to do with the ",
"hypothalamus",
". "
] | [
"We also have a class of receptors called thermoreceptors. These are sensitive to changes in temperature. They are located within the skin and are responsible for measuring the temperature of the environment. When we 'feel' hot, theres are the receptors being activated as our body is trying to loose heat to maintai... | [
"Something like this?",
"Thermoreceptor",
"?"
] |
[
"What are the health/rest differences between hitting my snooze button three times every morning and just setting my alarm 27 minutes later?"
] | [
false
] | null | [
"reference?"
] | [
"reference?"
] | [
"I believe the most restorative stage in a sleep cycle is during REM. Disrupting this state can have drastic effects on your ability to feel rested (I suffer from sleep apnea which causes me to repeatedly come out of deep sleep to start breathing, I think the medical term for this is: Pain-in-the-ass-itus). I could... |
[
"What impact would the eradication of cancer and other major diseases have on the world?"
] | [
false
] | Reading articles in I see stories about how if the current trend in food prices doesn't change, there will be a worldwide food shortage by 2013 and the less fortunate will no longer be able to afford food. If scientists were able to cure cancer and other major diseases, it seems to me that the world would become even m... | [
"Layman: Any significant move to lower mortality rates would initially lead to a lot of relief for many. In time, it would lead to population growth that would in turn strain resources. As a result, breeding rates would drop and eventually, the population would level off.",
"Population models are set up using (... | [
"I hope that by that time people will be able to choose the family size they want. If in poor countries children don't die of diarrhea, malnutrition or malaria anymore, then perhaps their parents would also, like in developed countries, choose to mostly have 2 or 3 children and not more than that. ",
"A scientist... | [
"You double posted, but that's fine. 502 means it went through and 504 means try again, ",
" I've recently seen a lot of 504's actually go through for me. "
] |
[
"If you looked at the DNA extraction of a strawberry [from enclosed video] through a microscope, would it look like a double helix?"
] | [
false
] | [deleted] | [
"Histones are on the order of ",
"6 nm",
". This is about 50x too small to resolve with a light microscope. You would see DNA as a blob or a strand, not as a helix. "
] | [
"The helical features are too small to see with a microscope. Even with something higher resolution it just looks like a strand. You need to look at x-ray diffraction patterns to infer the helix pattern.",
"-someone who looks at DNA through a microscope."
] | [
"To see the double helix you need something like a ",
"scanning tunneling microscope",
".",
"Some images:\n",
"http://electron6.phys.utk.edu/phys250/modules/module%202/tunneling.htm",
"\n",
"http://www.accessexcellence.org/RC/AB/IE/Future_Of_Genetic_Research.php"
] |
[
"What happens when an object rotates at the speed of light? Is it even possible?"
] | [
false
] | [deleted] | [
"Can't happen. Not only for material/engineering reasons as QuantumCreeper says, but because nothing can go that fast. If you solve the equation of motion for a constant torque, you'll find that it just gets faster and faster but never reaches the speed of light at the extremities, similar to linear motion.",
"If... | [
"The fastest spinning ",
"pulsar",
" clocks 70,000km/s, or 24% of the speed of light at its equator.",
"Edit: wrong its - brain holiday."
] | [
"that would be crazy to look at close up (ignoring the fact that there would be quite a few things that could kill you). I imagine you wouldn't really notice any motion of it with your eyes (and I know there wouldn't really be anything to follow in the motion anyways because it is so uniform). If you were along t... |
[
"The MacCready explosion states that 10,000 years ago humans and their pets and livestock made up 0.1% of terrestrial vertebrate biomass, today 98%. How accurate is this?"
] | [
false
] | I'm watching a talk by Daniel Dennett where he cites this (stating it as a matter of fact) and I'm feeling a bit skeptical about it, but a google search does not really help me because it just leads to people repeating this statement or other pages about Dennett. Does anyone have an idea how close these figures might b... | [
"I've never read of anyone who claimed to know ",
"Paul MacCready's",
" original calculation, which I regard as questionable at best. MacCready was a gifted aeronautical engineer but that hardly qualifies him as a primary source in unrelated realms.",
"As for determining the accuracy of the statement, we woul... | [
"This is one of those \"That which can be asserted without evidence can be dismissed without evidence\" type claims. Frankly, it is so absurd I wouldn't waste my time worrying about it. Food chains don't work that way.,"
] | [
"Is it a coincidence that this was posted and 12 hours later XKCD posted this comic/chart?",
"http://xkcd.com/1338/",
"From that figure it looks like 98% isn't too far off. This is just for mammals though."
] |
[
"In Vitro, can 2 entirely different species egg and sperm Fertilize ? If so, do they develop into zygotes?"
] | [
false
] | One definition of species I've heard is inability to mate and produce offspring. Does the process even begin or does the sperm look up at the egg and say " Well boys no point in breaching that." | [
"For some species they certainly can. For example a donkey and a horse can be bred to produce a ",
"mule",
". However the mule is sterile (the vast majority of the time) and therefore we don't consider donkeys and horses the same species.",
"There is also a lot of subtlety to the definition of a species. Some... | [
"Sperm and egg cells have identifying surface proteins (generally glycoproteins) and matching protein receptors that allow them to recognize each other and initiate fusion. In fact, there's a whole series of these signal-and-receptor interactions between the cells that have to go right before, during, and after fus... | [
"Ok so to put the question a bit more bluntly. If I had sex with a female panda and my sperm came into contact with the panda egg, would it even attempt to inseminate or would it just swim off and die? I know a living organism would never be produced (although it would probably be in the pandas interest to at least... |
[
"Can spacetime wrap in such a way that the universe would be finite with no border ?"
] | [
false
] | Maybe something like a 4 dimensional sphere ? | [
"A 3-torus (hyperdonut) would be an example of such a shape. If the universe were like that, then light from distant objects could reach the Earth through multiple paths, and we'd see distant objects at multiple points in the sky. ",
"We can look for signs of that",
", to see if the universe has that shape. We ... | [
"But doesn't that just means that the universe is too big for us to detect the topology? If it's a 3-torus larger than the visible universe then surely the light after the \"wraparound\" couldn't reach us."
] | [
"Yep. Sometimes the best you can do is constrain"
] |
[
"What are the implications of neutrons having a magnetic moment? Can they be magnetically confined/guided? How do they interact with external magnetic fields? Can they have their own magnetic fields, and how would that field look? Would it be able to induce currents in nearby conductors?"
] | [
false
] | null | [
"They can be guided magnetically, but generally only if they're moving very slowly. For example, ",
"ultracold neutrons",
" can be contained in what is essentially a big magnetic bathtub.",
"They interact with an external field the same way that any dipole does. Like the needle of a compass, they prefer to al... | [
"The magnetic moment of a neutron is a thousand times weaker than that of an electron. You need huge magnets to get a tiny force."
] | [
"The potential energy of a magnetic dipole in a magnetic field is: ",
"Energy ~ mu * B where mu is the dipole moment and B is the field.",
"The magnetic dipole moment of a neutron is somewhere around 100 neV / T, or a 1 T field gives an extra 100 neV of energy (I don't recall the exact number). For comparison t... |
[
"Does air have its own form of “surface tension” the same way water does?"
] | [
false
] | My assumption is that the atoms are too far apart to create any form of tension compared to water. But would this be the case in a pressurized environment? | [
"There are ",
"small correction terms",
" to the ideal gas law to account for the interaction of molecules, this often includes a pressure, but I don't think you can call that \"surface tension\" as it is not a surface effect."
] | [
"And air does not have cohesive properties to the degree water does due to less intermolecular forces."
] | [
"That water is in the form of water vapor though, so it behaves like a gas, while surface tension is a phenomena that is specific to liquids."
] |
[
"Why is it that when images are quickly inverted back and forth there appears to be movement?"
] | [
false
] | I've been wondering this for a while and I'm not entirely sure I understand it. Hopefully someone here can explain it a bit further. | [
"I don't think that's what OP was asking. When he says \"invert\", he really meant inversion of brightness - as in the negative of a photo but otherwise unchanged contents, like the sample provided."
] | [
"Opps my bad. I just checked the GIF frame by frame (there were four in total), the first two frames were the normal B&W, just shifted slightly to create a movement, the latter two frames were identical except inverted.",
"If I hazard a guess, it's an optical illusion caused by the B&W inversion which made tracki... | [
"Right, it sounds like the OP didn't notice that there is more animation in that GIF than the simple inversion."
] |
[
"Dark matter is its own antiparticle?"
] | [
false
] | In concerning Fermi telescope gamma ray data that might indicate dark matter annihilation in our galaxy, it is stated that dark matter is its own antiparticle. This assertion completely breaks my naive model of antiparticles having some characteristics in mutual binary opposition. Exciting article - but I'm completely ... | [
"Many particles are there own antiparticles, but it's currently unknown whether dark matter is.",
"Particles are certainly the opposites of their anti-particles in many properties, but this only means that a particle that is its own antiparticle must have those properties equal to 0. For example, the photon is it... | [
"pi-0 mesons are also their own antiparticle, as another example.",
"Probably the most interesting property which changes (note this is ",
" for a neutrino) between a neutrino and an antineutrino is its ",
"handedness",
"."
] | [
"Don't neutrinos also have no charge? Why would they have an anti-particle and not a photon?"
] |
[
"What heppens to buprenorphine (or other opiods) after they have attached to the receptor?"
] | [
true
] | I'm very curious to know what happens, or what causes the opioid (opiate) to be removed from the receptor after it has attached and completed its job. Is there like an enzyme in the brain (not the blood or liver unless that IS the only thing that causes it to be removed FROM the receptor) or another type of chemical th... | [
"As far as I am aware there is no such molecule. Opioids, like many ligands, bind receptors in a dynamic equilibrium meaning they are constantly binding and dissociating. Some are 'stickier' than others but none of them require enzymatic removal. The life cycle of the drug starts with high concentrations in your bl... | [
"Thank you, this helps too."
] | [
"The answer your looking for is most likely GTP. Opioid receptors are g coupled protein receptors (GCPR) which. Understanding this mechanism requires a basic understanding of biochemistry and the central dogma of molecular biology. But you can think of GTP as a molecule that does work. So the opioid binds, causes a... |
[
"When I'm sitting in a quiet room, why do things \"click\"?"
] | [
false
] | null | [
"They are always occuring, a cacophony of sound that we usually remain oblivious to. Our brains filter out an enormous amount of stimuli that they decide is unimportant to focus on. When there are fewer environmental stimuli, we tend to notice the smallest things as or minds work to occupy themselves - the itch on ... | [
"Temperature changes, weight changes due to you moving around, seismic motions from the outside environment..."
] | [
"Thermal expansion/contraction. Changes in moisture level also contribute to this, your walls absorb and release moisture, same with wooden furniture, that causes expansion/contraction. Buildings are not entirely stiff and unmoving. They move, sway with the wind, respond to people walking around. These movements ar... |
[
"Can sound create heat?"
] | [
false
] | [deleted] | [
"Yes, sound waves can and frequently do create heat. In fact, in some ",
"sonoluminescence",
" experiments, sound waves create bubbles in water which collapse, in the process heating up to as much as 5000 K."
] | [
"Yes, in fact ",
"you can use it to burn tumors"
] | [
"This is a very special phenomenon and it's actually the cavitation phenomenon that is generating heat, not the sound wave itself. "
] |
[
"How is a (returning) flu season impacting a Delta coronavirus wave in a given country?"
] | [
false
] | null | [
"Where Delta variant inspired mitigation measures are in place, this year's flu season may resemble last year's, since the flu virus is less transmissible than SARS-CoV-2. Flu activity was extraordinarily low throughout the 2020-2021 flu season both in the United States and globally, despite high levels of testin... | [
"Australia basically skipped flu this year, like we kind of skipped it globally last year. Mitigation methods such as distancing and mask wearing have not been sufficient to prevent COVID-19 from spreading, but have successfully prevented transmission of influenza and the common cold so that their prevalence have b... | [
"Others have talked about how Covid restrictions curb the spread of influenza, I would like to add that the traveling between the north and south hemispheres are still not back to normal, and that is theorized to be a major disruptor to the flu - normally we expect the flu to \"chase\" the flu seasons from one end ... |
[
"Is there evidence that people better form memories of situations in which they were the main “character” than they do if they were just an observer (or more peripheral)? What are the theories around this?"
] | [
false
] | null | [
"I am a psych \"student\" to take what I am saying with a grain of salt.",
"I am unaware of how effectivly learning takes place when someone feels they are \"part\" of the chain of events, but I do know two things from what I've learned:",
"When people have a certian amount of control it stimulates exploration ... | [
"What you're talking about is the self-reference effect. People remember things better when they are directly involved or when they can directly apply the knowledge to themselves.",
"http://en.wikipedia.org/wiki/Self-reference_effect"
] | [
"I don't have evidence off the top of my head to cite, but from what I remember in my psych courses, you will definitely remember things better the more the event effects you. ",
"I guess the best example is that you would most likely have a much more vivid memory of a traffic accident that you were directly inv... |
[
"What is it that causes an LED to emit light, different from a normal p-n diode?"
] | [
false
] | [deleted] | [
"It is the issue of direct/indirect bandgap. Since the bandgap in Si or Ge is indirect, the electron must pass through an intermediate state to recombine with the hole, resulting in a transfer of energy to the lattice by emission of a phonon (or by an interaction with a crystal defect). Otherwise, ",
"conservatio... | [
"You are welcome. What I don't understand are the recent announcements by Intel and others that they are coming out with Si-based photonics transceivers. I don't know how these work. ",
"I have a vague recollection of reading that they had figured out how to grow GaAs (or GaInAs or some other compound) onto a ... | [
"You are welcome. What I don't understand are the recent announcements by Intel and others that they are coming out with Si-based photonics transceivers. I don't know how these work. ",
"I have a vague recollection of reading that they had figured out how to grow GaAs (or GaInAs or some other compound) onto a ... |
[
"Why do things that are far away look more blue?"
] | [
false
] | I'm talking about mountains, things in the sky, etc; | [
"It's ",
"haze",
": light scattering from particles in the atmosphere. This is also why the sky is blue. There's actually a better discussion of the optics on the page for ",
"aerial perspective",
" which is the idea that we can use the degree of haze/blueness in our visual field as a cue to depth / distanc... | [
"Essentially correct. It is because of Rayleigh Scattering, which is more effective at short wavelengths (the blue end of the visible spectrum). I could summarize but this ELI12 does a better job: ",
"http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html"
] | [
"Also called atmospheric perspective"
] |
[
"If a nuclear installation gets bombed by penetrating warheads etc., how big is the possibility of a meltdown and/or contamination?"
] | [
false
] | Obviously, this question has a somewhat actual political implication. I don't want to start a discussion on that, but rather see a scientific discussion about the technological workings inside the reactor. So the basic question is: Could it go critical, if the a bomb would hit the core? Thank you in advance. | [
"I read your question as containing at least two parts:",
"1) Could the explosion of a bomb at or near a reactor core cause it to go critical?",
"Bombs are designed to cause mechanical stress through exothermic reactions. If your bomb (somehow) caused a reactor core's fuel rods to become located further away fr... | [
"Real nuclear engineer showing up. Containments are made of either one integrated shield/containment shell, or of a shield building with an inner containment shell. The containment itself does not handle pressures from the outside, and even a few pounds vacuum can be detrimental to containment shell operability, ho... | [
"Critical specifically refers to the core eigenvalue k. ",
"When people said Fukushima was critical, they meant it in the sense that it was a high priority problem, not in any nuclear physics sense. The cores were subcritical from about 3 seconds after the earthquake hit and have stayed that way since. "
] |
[
"Can someone give me a good response to the statement \"Worms can be born in apples because sometimes a worm will come out of an apple with no entry holes.\""
] | [
false
] | [deleted] | [
"This begs a few questions....what makes you say that a worm will sometimes come out of an apple with no entry holes? Have you seen such a thing? What makes you say that an entry hole must be visible? "
] | [
"http://en.wikipedia.org/wiki/Codling_moth",
"The moth lays eggs in a tiny pinhole in the apple skin, they grow inside the apple."
] | [
"I think the OP was asking for a response to some one else who said what he has in quotes."
] |
[
"What is laughing? What causes everyone to make the similar sound?"
] | [
false
] | null | [
"Not the complete answer by any means, but there's evidence that laughter has a common evolutionary root between humans and some apes, and perhaps serves some sort of social purpose.",
"The results of this study indicated that chimpanzees produce ",
" that is distinct in form and occurrence from their ",
". T... | [
"Another question might be, do other primates laugh? And, what sort of context do they laugh in?"
] | [
"it has been shown that human infants and chimpanzee infants have a very similar laugh sound pattern"
] |
[
"I have a very specific question about the death of our star and supernovae (s?). Please look inside for details."
] | [
false
] | [deleted] | [
"Without having many details at hand, and I'm sure someone can explain the fusion process better that I, Supernova are after all fusion has expired and caused by the mass of the red giant collapsing in on itself. this compression effectively blows the star apart (core-bounce) which is what a Type II Supernova is. ... | [
"It's not that suddenly adding iron to the star stops the fusion. What happens is that you cannot gain energy from fusing beyond iron. So at its core would be some iron and stuff that is no longer fusing, but the other elements, if they have sufficient pressure, can still be fused up along the chain toward iron. ",... | [
"As others have noted, iron doesn't kill a star, just like ashes aren't what cause a fire to go out.",
"Even if it did, the sun already contains 0.16 % iron, or 53 Earth masses of iron. Another earth mass or 2 wouldn't be a very large difference."
] |
[
"Can someone explain to me what the No Boundary Proposal to the beginning of the universe is?"
] | [
false
] | [deleted] | [
"If the big bang is the beginning of time, then you would consider that point in time to be an 'edge' to the universe. Looking at the timeline of the universe, you would see a point where that line ends.",
"If instead you think of time as the radius of a circle, then there is a point where you can't get any small... | [
"So then time is just expanding with space?"
] | [
"Think about it like this; as the radius of the circle (time) increases, the circumference of the circle (space) gets bigger."
] |
[
"What causes LCDs to \"ripple\" when touched?"
] | [
false
] | null | [
"It's a liquid between two plates gapped by spacers to maintain an even width. Voltage is applied to the lc which rotates the molecule. This changes the refractive index of the lc which passes different colors depending on how much voltage is applied. When you press on the screen you are changing the the thickness ... | [
"The liquid in \"Liquid Crystal Display\" gets disturbed by the pressure and flows away from the disturbance.",
"Flowing like that changes it's behavior from the precise alignment normally induced by the tiny electrical charges."
] | [
"Same answer as the other guys in about a hundred less words. You won my vote. "
] |
[
"How does a chameleon process visual input from its two independent pupils to form a singular clear image of its surroundings, even when pointing in completely different directions (e.g. one eye pointing forwards and one eye pointing to the side)?"
] | [
false
] | null | [
"They process both images independently, which allows them to track two independent objects at the same time, this is called monocular tracking. They also have a binocular vision, where both eyes are used to create an image. Usually they use it to focus on prey. It is also believed that they can split their attenti... | [
"Also, chameleons don't camouflage themselves. That's ridiculous.",
"Why is it ridiculous? Here's a paper called \"Predator-specific camouflage in chameleons\":",
"http://rsbl.royalsocietypublishing.org/content/4/4/326"
] | [
"There aren't receptors in their skin. It's microcrystals, like scales, that reflect light. They can change the reflection by relaxing their skin. ",
"Also, chameleons don't camouflage themselves. That's ridiculous. They relax the crystals to reflect less light, thus heating up more from light. Reptiles rely on ... |
[
"Is human interphase DNA always present as 46 separate chromatin \"chunks\" in the nucleus or does it merge to form one huge chromatin strand?"
] | [
false
] | I understand that DNA is not often present in the form of chromosomes but it is mostly in the form of chromatin (I.e. during the cellular interphase). I think I remember that prokaryotic DNA is present as one large strand. Does this also apply to our human DNA during cellular interphase? Or is our somatic cell DNA alwa... | [
"The separate chromosomes do not connect to form a longer single molecule of DNA. They also do not remain packed up like the chromatin most people think of when they imagine chromosomes. \nWhile a cell is functioning outside of a replication cycle, the DNA is in a state of organized chaos. Some bits are tightly coi... | [
"u/vasopressin334",
" might be referring to what is called genomic loci, or chromosomal architecture. Examples can be found from images like figure 1 of this paper: ",
"https://www.jyi.org/2017-october/2017/10/2/chromosome-interactions-and-where-to-find-them",
"figure 7 of this paper: ",
"https://www.fronti... | [
"This scientific review paper",
" has some excellent figures that perfectly illustrate the point (skip the text and go straight to Figures 1, 3, and 4). Individual chromosomes are unpacked in their own distinct regions of the nucleus. As they are unpacked, there are binding proteins that pinch off \"loops\" by bi... |
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