title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"If you look at an object thats orange, it reflects orange, so is the object really orange?"
] | [
false
] | null | [
"No, the color of an object is the color of the light it emits. Every other definition is non-sensical."
] | [
"That's semantics, not physics."
] | [
"Techinically your not wrong..im just looking for a more definitive definition for \"color\""
] |
[
"If you could make a race car's tires, and the road it drives on, out of any materials know to man, what combo would perform the best?"
] | [
false
] | Cost and resources do not apply. Is asphalt and rubber the best? Or can we do better? | [
"Well it depends what you mean by \"perform the best\".",
"Let's start off at the most basic level. Wheels work because of friction. An ideal wheel is one that does not slip at the point of contact. Imagine a car on ice - it wouldn't be going anywhere. The higher the ",
"coefficient of friction",
" the better... | [
"One thing to add, rolling resistance isn't strictly related to the tire deforming, it's caused by the tire absorbing energy when it's depressed but not pushing back with the same force when it lifts off (so it absorbs a portion of the energy). If the tire is very very hard and very \"springy\" then you can have th... | [
"Engineering Toolbox tells me that aluminum on aluminum has a very high coefficient of friction (1.05), about twice that of steel on steel (0.5) and actually a little bit higher than rubber on asphalt (0.9). Aluminum would also have a low rolling resistance (not as low as steel, but lower than rubber). Additional... |
[
"How does our lack of secondary Olfactory organs alter our perception compared to animals with them?"
] | [
false
] | From what I've read, we're the odd ones out for our lack of a secondary olfactory sense organ. I never thought that whiskers and antennae were akin to smell, but it must give another level of depth to the animals world. What does science say? | [
"Its near impossible to accurately compare our perception with that of another species. Its hard enough to compare my perception with yours: ",
"https://www.youtube.com/watch?v=evQsOFQju08&list=TLCi3WNoJP4r2N-FhFE_QV-FOZqgFBLhCC",
"But suffice it to say, while we are lacking in the smell department, we have adv... | [
"True, I guess we only know our own perception. It just seems that there's an entire other complexity to things that were missing out on, such as how ants can follow pheromone trails so perfectly. I think we could probably put that sense to use better than other species. Especially considering that most animals do ... | [
"Its tricky to answer questions which begin \"why would evolution\"",
"The best answer is probably going to be a little vague: At some point the benefit of perceiving the world as we do, was greater than retaining a reliance on pheromones or secondary olfactory organs. As that happened there was no pressure to ma... |
[
"If I bombarded a covalently bonded molecule with beta radiation, would the constituent atoms separate from each other?"
] | [
false
] | [deleted] | [
"Yes, and you actually don't even need beta particles to do it. Beta rays are just electrons with a lot of kinetic energy. I don't know if you have heard of mass spectrometry, but it is an analytical technique to quantify and detect compounds. We can tell what the compounds present are by looking at their fragmenta... | [
"Thank you for the great answer and taking the time to reply. I had not heard of mass spectrometry before this."
] | [
"The answer above was perfect, I just thought I would add a little something to help picture it a little better.",
"This may seem a little counter intuitive, but the beta radiation in fact knocks electrons from the bonds, forming a cation and a radical, instead of adding electrons to the bonds to form two anions.... |
[
"Could a bird fly in a large rotating wheel space station with artificial gravity?"
] | [
false
] | If you have a rotating wheel space station, large enough and filled with air, could a bird of some sort, fly in it? Or what would happen as the bird took flight from the ground? | [
"The air inside the space station is moving with the wheel as one body so the bird is not detached from the system when it is in flight, so it would be able to fly like it would on Earth and wouldn't be weightless.\nImagine a humming bird hovering beside a flower on this space station. To the observers on the stati... | [
"No, because the air is moving with the rotation of the space station."
] | [
"The only experiments I know of looking at anything like this involve ",
"pigeons going for a ride",
" (video) in the \"",
"Vomit Comet",
"\". While these parabolic dives are done to generate a weightless environment, they also subject the plane's contents (passengers and pigeons included) to positive and n... |
[
"Quantum dynamics and stationary states"
] | [
false
] | I'm reading the book "Introduction to Quantum Mechanics" by Griffiths. In chapter 2, he shows how to use separation of variables to separate the Schrodinger equation into time-dependant and time-independant parts. He says that this method can always be applied when the forces involved are conservative. He also shows... | [
"The probability for energy does not change on time because the forces are conservative. However, generally speaking the probability of other observables does evolve in time because the phase factors for each stationary state oscillate with different frequencies; Hence the time-evolution of the spatial wavefunction... | [
"The motion in this picture comes from the the interference between the various stationary states, which is time dependent because the phase of each energy eigenstate evolves at a different frequency.",
"To get a good feel for it, spend some time playing around with ",
"http://www.falstad.com/qm1d/",
" (",
... | [
"I see now, thanks."
] |
[
"How is a pulsar made to rotate 700 times a second? What happens that gives it this rotational speed?"
] | [
false
] | [deleted] | [
"Observe closely what happens when the skater pulls in her arms. Now transpose to a collapsing star."
] | [
"Conservation of angular momentum. If you spin in an office chair with your arms out, and then pull your arms in, you'll notice that you start spinning faster. The same thing has happened with pulsars, except they've gone from tens of millions of km across to merely tens of km across. That necessitates a colossal i... | [
"To further illustrate this point: A star's core prior to going supernova could be something like a few times 100,000 km in radius. A neutron star is about 10 km in radius. So it's like if a skater with arms that reach 1 meter from the center of their body were to contract so that their entire body was less than ",... |
[
"What is that smell of rain exactly?"
] | [
false
] | Can't exactly describe it, but you know what I mean.. There is a distinct smell in the air just before rain or during rain.. | [
"When it is about to rain, the barometric pressure drops. ",
"If the pressure drop is rapid, a low pressure system is approaching, and there is a greater chance of rain . ",
"Wikipedia",
"Consequently, more VOCs (volatile organic compounds) evaporate. This is a consequence of ",
"Le Chatelier's principle",
... | [
"No, that is the smell of rain. What you describe, ",
"geosmin",
" is one ",
" of rain, in the same way that ",
"vanillin",
" is one component of the taste and aroma of ",
"vanilla",
". It contributes to the smell; it is incorrect to say that it ",
" the smell. ",
"Quoth Wikipedia",
":",
"Geos... | [
"That is correct, but that's not the smell of rain.",
"Rain smells different in cities with no parks, to being out in a forest/grassland, all because of acintobacteria producing geosmin."
] |
[
"If you traveled 66 million light years from Earth (instantly) and could look back on Earth's surface, would you be able to see what Earth looked like 66 million years ago?"
] | [
false
] | null | [
"I'm not going to check the actual age, I'm going to focus on the photon density you could see at that distance. ",
"In a shell around the earth at any given time, the photon density is roughly 10",
" photons per cubic metre. This is a very rough approximation, but it should be sufficient. If someone has a bett... | [
"Yes, the light you see from a star millions of light years away shows the star's position and activity from millions of years ago. With a powerful enough telescope you would see 'history' on another planet. "
] | [
"Yes!"
] |
[
"Is it bad to not fully charge a rechargeable battery?"
] | [
false
] | I am being told that if I plug in my phone before it is low on energy it is bad for the battery, and if I take it off the charger before the battery is fully charged it is also bad for my battery. Is this true? If so what is the reason? Thanks | [
"This is completely wrong with lithium batteries. Lithium cells generally like being stored cool and at about 40% charge. To prolong life, you should neither fully discharge them nor fully charge them; they like being in the middle of their charge region. (Source: I have built an electric car doing quite a bit of s... | [
"Is there anything wrong with letting my electronics charge up all night long? I've heard conflicting information about proper charging methods and it sounds like you're the guy to ask. "
] | [
"Android phones charge to an optimum level for Li-Ion, I believe around 90-95% and then bounce around in that range, but the OS will report 100% regardless of the current actual charge. A lot of people experience a severe drop in the displayed battery charge early after pulling the phone of the charger for this rea... |
[
"Just how out dated are our space probes?"
] | [
false
] | If we could pull some Star Trek shit (just as an example) and replace Voyager I with a state of the art probe, how much more in depth would the results be? Same thing goes with all probes we've sent out. With the rate our computer processing speed is increasing, data storage increases and overall technology evolution, ... | [
"The voyager probes are over 30 years old, and they took a few years to spec and build, meaning the tech is 35 years from the bleeding edge of science. As an example of this - data storage on the Voyager probes is done on an 8 track tape recorder.",
"'how much more in depth' the information you gather would depe... | [
"I'm saying, replace Voyager with ST: Voyager (oh god, I went there)\nLets give it all the best equipment we currently have and it gets to replace the original. For simplicity lets say it's replacing for the same mission. Basically how much information are we losing by the technology being so old?"
] | [
"How are you measuring the information lost?",
"Modern storage holds millions of times more information in the same space compared to mid-70s technology. The utility of that information probably does not scale well. How many more questions could we answer? A hundred? A thousand?",
"In addition, the methods of a... |
[
"What's the absolute worst result of a geomagnetic storm? Also, what are the durations of these events?"
] | [
false
] | I've heard that solar flares can royally screw with communications equipment and long-distance power lines. In the insurance industry there's the term 100-year flood, against which people prepare for making safety standards. The solar cycle is 11 years but it experiences upticks and downswings - what would a 1000-yea... | [
"Well, a 500-year geomagnetic storm ",
"hit in 1859",
". Telegraph systems failed, aurorae turned night into day. Problem is, nowadays we have satellites, lots of sensitive electronics, power grids etc. Think how reliant we are on electricity... a 1000 year storm poses a very serious threat to transport, clean ... | [
"No. Be afraid."
] | [
"do you mean $1-2 ",
"?"
] |
[
"What is gravity? What are the 4 forces in general?"
] | [
false
] | null | [
"Every analogy breaks down if you take it far enough. The only thing that's exactly like something is the thing itself. So you'll just have to take it in broad strokes.",
"http://xkcd.com/895/"
] | [
"Answering the first part of your question:",
"http://www.reddit.com/r/askscience/comments/18yug5/whats_our_best_theories_on_what_causes_gravity/",
"http://www.reddit.com/r/askscience/comments/nlwsl/so_we_know_what_gravity_does_but_are_there_any/",
"http://www.reddit.com/r/askscience/comments/ee63i/what_gets_... | [
"Thanks for the xkcd! This scenario pops up a lot."
] |
[
"What is the consistency of outer space? Does it always feel empty? What about the plasma and heliosheath and interstellar space? Does it all feel the same emptiness or do they have different thickness?"
] | [
false
] | null | [
"Space is not empty at all! We have entire branches of astronomy dedicated to studying the stuff between stars and galaxies (the so-called interstellar medium and intergalactic medium). The density of the interstellar medium is about one atom per cubic centimeter, and the density of the inter-galactic medium is muc... | [
"1 atom per cubic centimeter. It won't feel any different from the interplanetary space in the solar system. It's just a big nothing. It is not technically empty but for human scales it is very much empty. There is nothing there to touch, so you won't \"feel\" anything.",
"\nBut scientifically it is very interest... | [
"So if I stuck my hand out of a spaceship window, and disregarding everything else that might happen, would it have a texture? Like if I wave my hand in front of me, there's a little bit of drag on it and I feel wind. \nDoes the interstellar medium feel different?"
] |
[
"Are internal combustion engines the most efficient way to burn gasoline?"
] | [
false
] | Noob here, if gasoline had to be used to say, make electricity, what would be the most effective method? ICE? Turbine? | [
"The most efficient combustion engines currently are \"combined cycle\" turbines. Typically a gas turbine, similar to a jet engine but designed to produce power to a driveshaft rather than thrust, produces some power and the hot exhaust is then used to power a steam turbine for more power. The efficiency can be aro... | [
"No. A gas turbine engine would be the most efficient way to burn gasoline. And this goes for most hydrocarbon fuels. ICEs typically don't exceed 25% efficiency, whereas turbines approach 99% in jet engines. ",
"So why do cars still use ICEs? Because turbine engines can't idle and they're only good at very high R... | [
"And a turbine isn't as responsive (throttle) and they are large and unpractical for a car or truck"
] |
[
"Do animals sleep-walk?"
] | [
false
] | null | [
"Yes.",
"Edit: ",
"This one",
" might be a better example of sleepwalking. The dog is actually upright and walking yet completely asleep."
] | [
"SO CLOSE!. I was thinking the same thing."
] | [
"yes, they even have what would be considered the opposite of sleep-walking, sleep paralysis "
] |
[
"What marks where one gene ends and another begins in a DNA thread?"
] | [
false
] | null | [
"Genes typically have a sequence up stream from the gene which is called the promoter and signals to the polymerase where to start copying from: ",
"http://en.wikipedia.org/wiki/Promoter_(genetics)",
"All genes end with a \"stop\" codon which tells the polymerase to stop copying, ATT, ACT, ATC are the DNA seque... | [
"Just as a side note genes usually posses more than one stop codon when they end. It's more of a stop stop stop stop message, as a single stop codon can frequently passed over due to ",
"nonsense suppressor",
" tRNA. "
] | [
"I'd like to clarify something here.",
"A gene is not analogous to the coding sequence. Not all genes code for proteins.",
"Arguably, a gene starts at the transcription start site (TSS) and ends at the transcriptional end site (TES). This comprises untranslated regions at both ends of the resulting piece of RNA... |
[
"Do magnets work at absolute zero?"
] | [
false
] | Do magnets work at absolute zero? I know that atoms will no longer move at absolute zero so I was wondering if that means they will not attract towards one another either. And if that is true, does mean the temperature of a magnet will affect how strong it is? | [
"Yes, many materials are magnetic at zero temperature. Your misunderstanding is here:",
"I know that atoms will no longer move at absolute zero so I was wondering if that means they will not attract towards one another either.",
"First of all, it isn't quite true that all motion stops at absolute zero - in quan... | [
"It's really not possible to \"stop\" an electron - this would violate the Heisenberg uncertainty principle. There's always some spread in either the position or momentum of a particle. You can have electrons \"localized\" around a certain position with a fairly narrow width (insulating materials are well-described... | [
"exactly, it's the energy resulting from Heisenbergs uncertainty principle applied to a bound state."
] |
[
"Are there black holes that feed on galaxies?"
] | [
false
] | We know theres a black hole at the center of every(?) galaxy but is it possible for a black hole to exist that feeds on entire galaxies? Probably a stupid question, sorry. | [
"Not really. It's actually quite hard to get something into a black hole. Their gravity is strong, but they're very small in radius for how massive they are. Stuff will generally just swing by a black hole, unless it's really really close. Even then, it'll get torn apart into a disc of matter around the black hole ... | [
"A light year isn't related to the actual time that light takes to go somewhere - it uses the speed of light in a vacuum in flat space.",
"Honestly, in astronomy we typically use parsecs instead, where a parsec is a bit over three light years. But the general public is more used to light years for some reason."
] | [
"To add to that, there's the Eddington limit, which puts a quite hard limit on how much matter a black hole can eat."
] |
[
"Why do our bodies decompose when we die but not when we’re alive?"
] | [
false
] | null | [
"We actually do, we normally would only see it as an infection. ",
"We are constantly under attack by plenty of microorganisms but we most oftenly than not, manage to keep them at Bay with white blood cells or other defenses.",
"What happens when we die is living cells are no longer fighting the invading microo... | [
"So really our immune system is the main defense that we have. Sounds like a lot of work for this system. How does it manage to fights all these microorganisms at once especially when we get sick (flu, cold, etc..)"
] | [
"It's a lot easier to keep things at the door when we are taking showers, washing our hands, and other hygiene. Our white blood cells are always throughout the body and when something is wrong they know to converge and overwhelm the new foreign cell(s) before they can get a foothold."
] |
[
"What happens to the matter in our bodies when we lose weight? Do we pee/poop/sweat it out?"
] | [
false
] | The matter doesn't just vanish. For example if someone loses 20 pounds, where does the 20 pounds go? | [
"You breath it out as carbon dioxide and water."
] | [
"You know how we breathe in oxygen and breathe out carbon dioxide? That carbon comes from fats and sugars in our body."
] | [
"The reverse happens with plants. Most people think the mass of trees (mostly carbon, hydrogen and oxygen) come from the soil, but if that were the case, there would be a hole in the ground around trees. In fact, it's mostly from the air.",
"It goes to show how we tend to ignore the mass of gases, but it's all ve... |
[
"Why do I sink faster in water than others?"
] | [
false
] | null | [
"To rephrase what Zerowantuthri said. Fat is a lot less dense than water, so pure fat actually will float. Muscle is much more dense than water, so pure muscle will sink readily. Its the mix of fat and muscle in people which makes it easier or harder to float. More fat = easier to float, more muscle = harder to... | [
"Buoyancy in water is all about water displacement.",
"Generally the fatter you are the easier it is to float. If you are more muscular with very little fat then you will sink. This is why it takes a toll on you. You have to work to stay afloat where others can do little to no work for the same effect."
] | [
"My first question was going to be whether you've ever broken a bone. I saw an article posted here on reddit about a guy with the same issue and it turned out he had a condition that gave him very dense, strong, heavy bones. Look it up. I can't remember what it's called."
] |
[
"Why don't we simulate neural activity on a small scale with computers?"
] | [
false
] | For instance: A neuron is a biological I/O system, whereby neurotransmitters are used create a flow of information in a synapse, and more importantly the entire brain. Couldn't we just do this? Even on a small scale, such as making a digital signal get transmitted among a network of virtual "cells". | [
"We do, such as the Blue Brain project. The best way to examine this is via numbers. There are ~100 billion neurons in the brain each with thousands of connections. A typical brain by most estimates has ~100+ trillion synapses. To be clear: ~100,000,000,000,000. ",
"Now imagine if every synapse you where sim... | [
"IBM claimed a cat brain but as many have pointed out, it in no way was even near the power of a real cat brain.",
"http://news.discovery.com/tech/cat-brain-computer-hype.htm"
] | [
"Definitely! At a theoretical level we should be able to refine our models of neural networks so that they more closely mimic actual neurons.",
"Once you get into the details though... It's non-trivial to identify which aspects of a cell are relevant. Does the location of specific receptors have an influence in f... |
[
"What is the equation that governs the speed at which a smell propagates through air?"
] | [
false
] | Suppose I fart. What is the time it takes for my fart to reach the noise of someone 3.14159 meters away? | [
"Fokker-Planck equation",
"https://en.wikipedia.org/wiki/Fokker-Planck_equation"
] | [
"o.o How do I use this?"
] | [
"You need to know the initial distribution of the smell after you fart. You can consider it to be a gaussian with a very small width. If there is no wind, then it means that the drift term is negligible. So now you know f(x,0), using the second equation in \"One dimension section\", you can solve for f(x,t). Since ... |
[
"My supermarket now only sells flouride free tooth paste. Are there any legitimate reasons to do this, or is it just mass paranoia?"
] | [
false
] | null | [
"A study that was in Nature found that fluoride in toothpaste was beneficial.",
"The results showed that less wear was produced in the presence of the fluoride toothpaste than in the presence of the non-fluoride toothpaste with an otherwise identical formulation (P < 0.001), and that the amount of tooth wear in v... | [
"I skimmed over your large post and it seems to be centered around ",
" fluoride in drinking water. If you're ingesting toothpaste, you're doing it wrong (i.e. fluoride in toothpaste is relatively topical in application by comparison)"
] | [
"This was my response to someone else who wanted to know about fluoride concerns, so it may not make 100% sense here but I think it should do the job:",
"So far, and this is nothing new, the only positively attributed source of concern regarding fluoridated water involves fluorosis in developing children. In mos... |
[
"How does our body's immune system distinguish between pathogenic microorganisms and commensal?"
] | [
false
] | Microorganisms are an essential part of our body and even some of the pathogenic (potentially) microbes are also present on our body, classic example being Candida albicans. So how does our body allow such microbes to sustain in/on our body? And what makes our body to show an immunological response if such microbes are... | [
"Yes and no, separation is an important part of keeping microbes out of areas where they can cause damage however the immune system regulates all microbes to some extent and recognizes them based on a variety of factors but some have a privileged status. This isn't really my area but commensal microbes engage in cr... | [
"Your body doesn't. It's more microaganisms stay in their place, and don't travel to areas that can harm you. Bacteria on your skin is natural but is opportunistic ,if it enters a cut for example, it can cause infection. Even healthy gut bacteria are separated from your tissue via mucus layers."
] | [
"Microorganisms actually within your body itself (not the GIT, lungs, skin etc) are always eliminated (well at least attempted to). On the other hand the immune system on the skin and mucous membranes are far more tolerant of microbes, a full immune response will not be triggered by the presence of microbes. Exactl... |
[
"What happens if you do not complete a course of antibiotics?"
] | [
false
] | null | [
"There is a small but significant chance that your body hasn't cleared the targeted bacteria. You then run the risk of a recurrent infection with the same organism. Additionally, you contribute to antibiotic resistance as the surviving bacteria have a higher chance of advantageous mutations."
] | [
"Not completely finishing a course of antibiotics may lead to a resurgence of the bacteria that survived the incomplete course. It can also lead to the emergence of drug resistance."
] | [
"Bacterial resurgence. The bacteria could become resistant to the antibiotics that you were given. You could then spread that resistant bacteria around so that others could have issues getting rid of the bacteria with prescribed antibiotics. ",
"Do us all a favor. Finish do what your doctor tells you. This helps ... |
[
"What caused the Cambrian Explosion?"
] | [
false
] | The Cambrian explosion was a period in geological history starting from 542 million years ago in which most classifications of life appeared. Is there any consensus in the scientific community as to what caused it? | [
"It's what's called an adaptive radiation. These can be caused by mass extinctions that leave many niches vacant, or by drastic environmental changes that cause new niches to form. It can also happen, as in the case of the first land-dwelling creatures, when species themselves discover a new environment full of pre... | [
"Along with being an adaptive radiation, the cambrian explosion is also due to the origin of hard body parts which fossilize well. Beforehand most everything had a soft body which decomposes too quickly for a proper fossil to be formed. So part of the huge \"explosion\" is the fact that suddenly (as in \"over the c... | [
"Exactly. It's really more of an explosion of fossils, rather than an explosion of life."
] |
[
"What exactly is the difference between nuclear fuel used for power generation vs bombs and why does fission cause only heat generation in one but an explosion in the other?"
] | [
false
] | null | [
"The differences are in the way they are designed, and the enrichment of the fuel.",
"Lets talk about bombs first. Nuclear bombs utilize very high enrichment fuel (>90%). Nuclear bombs are designed such that when they are assembled into a critical mass, the goal is for them to go prompt critical, then release as ... | [
"Uranium is usually used for power generation, and is mined from Uranium ore, which is mostly U-238 with a small amount of U-235. The latter is the fissionable component (i.e., the radioactive part).",
"In low concentrations, U-235 will decay in a fission reaction (it breaks apart), with heat as the by-product. ... | [
"I want to correct a lot here. Both U-238 and U-235 are fissionable, U-235 however is also fissile. That means it can fission by any energy neutron. ",
"U-235 decays by alpha decay, not fission. I don't even think it spontaneously fissions as a decay, if it does it is extremely unlikely. ",
"Reactors use a... |
[
"How do snakes right themselves underwater?"
] | [
false
] | Do snakes have the ability to change their orientation underwater? If their top is facing down can they 'roll over'? | [
"Yes, in the same manner cats use to self right in mid air. If you bend your body into a 'u' shape and roll your body along your spine, you play the rotational inertia of your body along its curved spinal axis against the (much larger) rotational inertia of your u-shaped body pivoting on a straight axis through you... | [
"Snakes are excellent swimmers and mostly use lateral undulation to move under water - basically by conforming their body they can push against the water, the same way you would push with your limbs to turn yourself over."
] | [
"Haha, I love smarter everyday, I was hoping for the cat video and you delivered!",
"Cheers"
] |
[
"Are there any specific geological features on Earth that contribute to the abundance of life?"
] | [
false
] | Things such as placement of continents/continental plates, ocean currents. Could the presence of those features on other planets be an indication of habitability? | [
"There are a bunch. Off the top of my head (others are welcome to complete the list):",
"A strong magnetic field, which acts as a radiation shield.",
"Large liquid water oceans, whether ice-covered or not.",
"active geothermal systems - From the observation of LAWKI, chemautotrophy is one of the 2 pathways we... | [
"I don't think you're looking for the biggest answer: The existence of fluids. The very presence of water and air - and their stability over long timespans - is the biggest thing that has brought the Earth to the point it's at today. But I'm guessing you aren't looking for this kind of broad geochemical answer.",
... | [
"The moon is big factor for life getting out of the ocean and onto land. \nThe moon cuasese tidal exchange. This ring and falling of the sea creates places where plants and animals get stranded and must adapt to air or die. (Tide pools) \nThis is a leading theory on how and why life left the ocean and populated lan... |
[
"How is measles back?"
] | [
false
] | If the disease was none existent in many countries, how can new kids without vaccines get them? Is it possible for diseases to be completely wiped if everyone gets vaccinated for generations? | [
"Because people move around and if it's not wiped out everywhere, it can be carried to places with insufficient vaccine coverage and start to spread again.",
"Yes, it is possible to wipe out a disease with good vaccine coverage. We did it with smallpox. We're close to doing it with polio. These are strictly hu... | [
"Now, we can't do that with a disease that is carried by animals and gets re-introduced to humans periodically, like Zika or Dengue or Ebola.",
"It is more difficult but not necessarily impossible. A lot of countries got rid of rabies, for example, several other countries brought down the rate a lot. ",
"Here i... | [
"Yes but that is because of a concerted effort to vaccinate domestic animals, which are the main intermediaries between wild animal reservoirs and humans. And some places also make an effort to vaccinate wild animals. Nevertheless, this can decrease but typically not eliminate a disease because coverage in wild ani... |
[
"How are we now getting warm colors in CFBs?"
] | [
false
] | For as long as I can remember, fluorescent lights were always blue, or a cool red. How are we now developing CFBs that have the warm white light? One of the sites I looked for them said 'use where color enhancement is not an issue'. What's different about the materials used in them? | [
"So the reason they're called ",
"\"flourescent\" lamps",
" is because the light that's actually produced inside the tube is UV light. The glass is coated with a material that absorbs the UV and re-emits it in lower frequency visible light. Previous coatings preferentially emitted towards the bluer end of the v... | [
"Because it can be lost as heat in certain instances. Essentially, the UV light pumps up the electron to an excited state, but when the electron decays back down to its relaxed state, it can give off some lower frequency light ",
" heat up its surroundings (the glass, etc.). And since heat is entropically favorab... | [
"Why exactly is the energy lost?"
] |
[
"If a 50 year old person receives a 20 year old heart in a transplant does the heart \"remain\" younger than the rest of the patient's own cells?"
] | [
false
] | If so is it theoretically possibly to live longer by simply replacing your organs as they get "worn" out? | [
"Not really a meaningful question considering most foreign organs get rejected after about 10-15 years because despite our best efforts of immunosuppression the human immune system really does not like having non-self tissue around. The cell material is in theory more fresh and could survive longer in situ, but pra... | [
"Well, foreign is pretty much anything that a) doesn't share the very specific subtype of MHC class I (the protein that carries and represents the antigens of a cell - imagine it's some kind of grail like protein that in itself can vary greatly within different people because of the large amount of allels in the ge... | [
"Thanks! I hadn't considered the immune response. I find it interesting that the immunosuppresive sirolimus has extended lifespan in mice and wonder if there's a connection between the activity of the immune system and lifespan in general."
] |
[
"How can some black holes be bigger than others?"
] | [
false
] | [deleted] | [
"There are 2 comments I cant see, maybe they have already explained...",
"A black hole can be considered to have no spatial dimensions - a singularity. (this may actually be because the laws of physics start doing strange things in a black hole)",
"A black hole however, has other properties such as mass, charge... | [
"Thanks, it does!"
] | [
"The ",
" \"black hole\" doesn't just refer to just the singularity inside. It refers to the whole region of space inside the event horizon. Just like if you dig a hole in the ground the term \"hole\" doesn't just refer to the bottom, it refers to all the empty space you created. "
] |
[
"More efficient to discharge/recharge a laptop or leave it plugged in?"
] | [
false
] | What's the most cost-effective/energy efficient way to run a laptop? Is it to use it unplugged until the battery is dead (or nearly dead) then plug it in and continue to use as it recharges, before repeating, or to keep it always plugged in? Or to use until the battery dies, then let it recharge before turning it back ... | [
"Adding to this -",
"While your laptop may automatically conserve power while running on battery, you still have to charge the battery between cycles.",
"Some management software may do this on its own when the machine is plugged in anyway (think Lenovo) - the battery contains some power management circuitry th... | [
"No, but it lets the battery live longer."
] | [
"Most Laptops switch to a powersave mode when unplugged, meaning you will use less energy if you only use the laptop while it is unplugged and charge it while it is turned off. On the other hand, most of the powersave-functions are actually implemented in software, so switching to 'powersave-profile' (or however it... |
[
"What do the \"morning after pill\" actualy do?"
] | [
false
] | null | [
"The \"morning after pill\" contains levonorgestrel, which is a hormone. This hormone can prevent ovulation. Sperm can survive in the uterus for a few days, but if you prevent the female from releasing an egg, they will have nothing to fertilize and pregnancy can be averted."
] | [
"You're on the right track. Levonogestrel is the hormone in the \"morning after pill\". It falls under a class of hormones called progestins. The primary function of a progestin used for birth control depends on the kind, dose, and the route of administration.",
"Just to be clear, the typical oral contraceptive p... | [
"Many thanks."
] |
[
"Can we estimate where the barycenter of the universe is?"
] | [
false
] | null | [
"The barycenter of the universe is not a well-defined concept. Whether the universe is unbounded (e.g., flat Euclidean 3-space) or bounded (e.g., a 3-sphere), there is simply no such thing as the barycenter.",
"Precisely, to be able to talk about the center of mass of some collection of particles, you need to be ... | [
"Strictly speaking, there is generally no center-of-mass on a manifold. Even in a region of spacetime where there is exactly one black hole has no center-of-mass. Again the issue is that there is no vector space structure, so it's not possible to define center-of-mass. (There's also the issue that although a spacet... | [
"Thank you for the answer! I wish there was an answer to the question as I had imagined it. I appreciate you helping me grasp the concept of a barycenter and its inability to be applied to the universe as a whole. ",
"As a follow up, could you calculate the barycenter of something like our galaxy? If you include... |
[
"How does the groundwater filtration system at Fukushima work?"
] | [
false
] | I was reading about the plan for Fukushima and became curious about for Cesium removal. How does it work? Bonus points - why aren't they worried about other radioactive particles? | [
"This system uses the principle of ",
"ion exchange",
" to strip cesium from water. The contaminated water is passed through beds of ",
"ion exchange resin",
" beads (called ion exchange columns). ",
"The canisters in the green room image are the ion exchange columns. The resin's chemical properties have ... | [
"Perhaps you can clear up another related question.\nHow does freezing the ground not expand the water when it freezes, pushing up on the surface?"
] | [
"The purpose of the freezing is to create a containment wall of ice around the contaminated area. Liquid water can't pass through a wall of ice. This containment prevents contaminated water from escaping the area, allowing them to pump up only the contaminated ground water for processing within."
] |
[
"Why haven't non-functioning, vestigial genes mutated into gibberish by now?"
] | [
false
] | Humans and apes have defunct genes for tails and vitamin-C. Birds have defunct genes for teeth. Since there is no selective pressure to keep them from accumulating mutations over time, and since they are millions of years old, why haven't they become gibberish whose original function is unintelligible? | [
"Genes that have lost their functions but resemble their \"original\" gene enough to be identified are called ",
"pseudogenes",
". If a gene has mutated completely to gibberish ie. lost all gene-like features it would be indistinguishable from background DNA sequences. So possibly some (or maybe lots) of gene... | [
"For starters, genes aren't a clear cut as \"Gene X does Y.\" There's a very complex interplay between various parts of the genetic structure of an organism. A change in a single gene can have effects all throughout an organism. For example, the genes that used to create teeth in birds would have played roles in... | [
"The vestigial genes the OP asks about don't code for protein and therefore can tolerate mutations better that protein coding regions.",
"Mutations like you describe in bone are inconsequential to evolution as they aren't passed down to offspring."
] |
[
"What happens to light when it enters a black hole?"
] | [
false
] | If I were to bombard a black hole with a huge number of photons, would the black hole behave any differently afterwards? Would I be able to measure any differences in terms of mass/event horizon? | [
"Technically it will become more massive, not \"heavier\". \"Heavier\" would imply an increase in weight which is relative to gravitational effects of other bodies, the black hole would have more apparent weight from the Sun's gravitational pull than from the Earth, for instance, while mass would be constant."
] | [
"When a crazy hobo shows up on your doorstep in 4 years asking if the photons stretch as they near the singularity, you better remember you said that."
] | [
"Depending on how you shoot them in you could alter the spin of the black hole as well. Increase the angular momentum enough and you could alter the accretion disk and relativistic jets, yes?"
] |
[
"Why do radio waves get blocked by chain link fences?"
] | [
false
] | I was once in my physics lecture, and the professor was talking about how different materials attenuated different frequencies of electromagnetic waves differently, and mentioned how everyday chain link fences could block long wavelength radio waves. This never made intuitive sense to me. Why does wavelength matter? ... | [
"and mentioned how everyday chain link fences could block long wavelength radio waves. ",
"It's because the wavefront diffracts (bends around) the wire in the fence making circular wave fronts, which will interfere and cancel themselves out. This only happens when the spacing between the diffraction grating is le... | [
"Also",
"Wouldn't amplitude actually make the difference for what does and does not \"hit\" the gratings of a chain link fence? ",
"The amplitude of an electromagnetic wave doesn't really refer to the physical \"size\" of the wave, but rather to the magnitude of the electromagnetic field",
"Edit: spelling"... | [
"What? You know radio waves are several meters peak-to-peak, right?"
] |
[
"Chemical Equation in Glow Sticks?"
] | [
false
] | [deleted] | [
"Commercially available glow sticks contain three primary ingredients. 1) a peroxide such as hydrogen peroxide or sodium peroxide, 2) diphenyl oxalate, 2) and various fluorescent dyes or (fluorophores). The type of dye or dyes used depends on the desired color of the glow stick.",
"Additional secondary ingredient... | [
"My understanding is that the reaction is generally basically",
"Luminol + O2 -> Excited Luminol -> Ground State Luminol + Light",
"You get the O2 by reacting H2O2 with Sodium Hydroxide.",
"I believe there are variations on this theme (e.g. catalysts) but this is the basics."
] | [
"My understanding (which is far from expert) is that Luminol (or other fluorescent compound), Sodium Hydroxide and H2O2 are the compounds that are present, before things begin. The point is that the H2O2 is in the glass vial inside the glowstick, and the dye (be that Luminol or something else) is in the outside, wi... |
[
"If we see through a \"pinhole\" formed by closing the index finger and thumb, why don't we see an inverted image?"
] | [
false
] | null | [
"Consider a ray of light that comes from above. As it enters your eye it will hit the bottom part of your retina. So the image is inverted on your retina already. If you add another aperture (without a lens) in front of your eye, it does not change the path of the ray, it will continue in a straight path as normal.... | [
"Won't a ray of light coming from above be focused by the lens to hit the upper part of the retina?"
] | [
"No. See ",
"here"
] |
[
"What are the ecologically equivalent large terrestrial scavengers that T-rex is compared to?"
] | [
false
] | I know there is some debate about whether the T-Rex was able to kill its prey, and I have seen they say it was a huge scavenger, but unlike many other dinosaurs, I don't realize exactly which animal can they compare it to, since I do not know of any huge modern terrestrial scavengers, can someone please fill me in? | [
"is there such a thing as a huge terrestrial scavenger?",
"Not currently, and there's a theory that a large non-flying terrestrial obligate scavenger is impossible, because they couldn't be energy-efficient enough to find enough carrion to survive. (Vultures manage by being very energy efficient.) ",
"(I th... | [
"Actually they just found a T-rex tooth fused to a prey dinosaur's spine which allowed them to infer that if the T-rex was a scavenger, it was probably facultatively so. BUT...answering your question, most canines would be a good example of a predator who acts as a facultative scavenger."
] | [
"I know plenty of those! I mean lions and bears are also facultative (thank you for the term) scavengers, but I was wondering if T-rex is to be compared, it should occupy a well established niche, right? So is there such a thing as a huge terrestrial scavenger? Our the fact that all big carnivores are predators sup... |
[
"Magnetic acceleration based weapons?"
] | [
false
] | [deleted] | [
"The US navy, along with BAE systems, a British engineering firm, have already made and test fired a magnetic railgun with some success.",
"Yes the weapon does exist, but, only as a test weapon. The benefits of this weapon are its incredible accuracy and power. The slug can be fired at speeds up to mach 7. The fl... | [
"It doesn't make sense to use a lightweight material as the projectile, not enough mass and therefore kinetic energy. I believe they use tungsten projectiles."
] | [
"In a railgun it doesn't matter if it's magnetic, the induced current due to (I believe) Lorrentz law. There are prototype railguns that use a small aluminum armature that vaporizes and creates a plasma armature that propels a plastic slug.",
"However, with a Coil gun does require a strong ferromagnetic projectil... |
[
"When talking about the age of the universe, which reference frame are scientists using?"
] | [
false
] | I understand that, the stronger the gravitational field the slower time would pass - wouldn't it mean that the early (more dense)universe had a slower clock overall? When the number 13.8 Billion years is mentioned, which reference frame has experienced all this time? | [
"Astronomers are generally using the cosmic microwave background frame (the frame in which the CMB is isotropic), but it actually doesn't matter that much. The percentage of matter that experiences strong gravitational fields or moves at relativistic speeds relative to the CMB frame is negligible. Any observer who ... | [
"This is correct - we are moving at about 0.1% of the speed of light relative to the CMB. Typical orbits speeds for stars and galaxies are ~0.01-1% of the speed of light (~30-3000 km/s). So the relativistic effects are only a small correction."
] | [
"Sounds more like a venture opportunity than a restriction!"
] |
[
"Is it physically possible to evolve a wheel?"
] | [
false
] | Title pretty much sums up the question. Is it at all possible for an animal to evolve a rotating wheel, or wheel-like apparatus, as a means of transportation? | [
"Yes! To escape predation, the ",
"golden wheel spider",
" forms a wheel-like shape by folding its legs around its body. This shape allows the spider to quickly \"cartwheel\" down the sand dunes of its native habitat.",
"Video of the golden wheel spider in action",
"Ridin' dirty version - this spider rollin... | [
"Some bacteria do, actually. ",
"http://cronodon.com/BioTech/Bacteria_motility.html"
] | [
"I suppose it comes down to how you define a wheel. While the spider obviously doesn't use an axle, its body does ",
"rotate around a specific axis",
"."
] |
[
"How are electrical signals traveling on neurons directed to its target?"
] | [
false
] | How do cells differentiate between an electrical signal traveling down an axon that is destined for different areas, for example the right great toe versus the left gastrocnemius? Cell biology textbooks does a great job at explaining the process by which the signal is passed between cells but how it reaches it's target... | [
"What ",
"/u/unia_7",
" said. Each nerve carries a large number of individual axons. Each axon either goes to one group of muscle fibers, or from one sensory receptor. ",
"That said, an axon CAN split in two and make synapses onto multiple separate target neurons. But it can't 'route' electrical signals d... | [
"I appreciate your username in the context of your area of expertise. Love it.",
"Feel free to delete this when you read it as it obviously violates sub rules."
] | [
"The textbooks don't explain it because there is nothing to explain. The cells don't differentiate anything, it's a one origin to one destination signal conduction.",
"A single axon runs to one single area (say, a receptor on your toe) and nowhere else. It never splits into two and never merges with another axon.... |
[
"Did some dinosaurs have hair instead of feathers?"
] | [
false
] | Scientists love the idea that dinosaurs had feathers that relate them to modern birds. But I read this article which talks about a dinosaur fossil that had "little 'fuzzy' feathers, almost like hairs." To me, a lot of fossils of larger carnivorous dinosaurs look like they had fur around them instead of feathers. is als... | [
"They wouldn't have hair in the strictest sense because mammals are quite distantly related to birds, and their common ancestor did not have hair. It would have evolved independently. Hair, feathers, and scales are all ",
"integumentary structures",
", though they're all formed in different ways. ",
"Feathers... | [
"This was interesting to read and is exactly what I was looking for. I wish I could give more upvotes. Thanks for putting time into writing it. "
] | [
"Cool, glad I could help!"
] |
[
"Are tractor beams scientifically possible?"
] | [
false
] | Watching Star Wars right now and I was curious if tractor beams could actually work/exist. | [
"Very small things can be manipulated using a focused laser. It's called optical trapping or optical tweezers. There is a similar effect that can be done with sound waves called acoustic levitation.",
"Optical tweezers",
"Acoustic levitation"
] | [
"/u/iorgfeflkd",
" gave a good answer, but optical tweezers do not scale well.",
"You could give the opposing ship an enormous electrical charge (say, with a particle beam) and give yourself an opposing charge. This is one ",
"proposed way to steer an asteroid",
". You don't really want a giant spark as soo... | [
"You missed his point about the spark, when the opposing charges come close they will discharge with a lightning bolt. That might cause damage so before they come too close you need to ground at least one end but that is not an easy task in space."
] |
[
"If you compress a gas or liquid enough, would it eventually become a solid because it’s molecules are so tightly packed?"
] | [
false
] | null | [
"Eventually, yes."
] | [
"Like how much pressure would there need to be. Would it turn into a black hole possibly at that point since it’s so dense?"
] | [
"Take water, for example. ",
"Here",
" is the phase diagram. At 200 degrees Celsius, you have to compress it to at least 3 GPa, and it will become solid."
] |
[
"How does the depo-provera birth control shot fail?"
] | [
false
] | From what I understand, the depo shot works by keeping you from ovulating and thickening the mucus in your cervix to make it more difficult for sperm to reach the egg. If this is true, how could it fail? Does the body "accidentally" release an egg during one of your cycles? Or is the shot 100% effective (with perfect u... | [
"The \"depo-shot\" is Medroxyprogesterone, a form of progestrin. As you stated this hormone causes ovulation to fail and the mucus of the cervix to thin. Your explanations are also correct. Hormones do not work perfectly on every person all of the time. There are a large amount of environmental and genetics factors... | [
"Thank you for your explanation! If I may I'd like to ask a few follow-up questions. ",
"So, the way you stated it led me to believe that, if a woman reacts as she is supposed to, the depo shot would be 100% effective for her unless she changed some aspect of her diet/environment in a way that effects the hormone... | [
"I'm sure that information is available, but I'm afraid I don't know enough to say what they are. As far as I know the depo shot is considered pretty close to 100% accurate, but it does fluctuate slightly on a person to person basis. Not sure I can give you all the answers you want though."
] |
[
"How can I test the double slit experiment at home?"
] | [
false
] | I failed miserably on my first attempt. Slits cut into a beer box and flashlight. The folks at said I need a laser and that the slits I made where probably too big. My question is this. Is there a way to conduct this experiment at home? I have a laser pointer. How should I construct the slits? what measurements have to... | [
"I did this by taking a piece of glass and holding it over a candle to get a nice thick layer of black soot on it, then holding two x-acto knife blades parallel to each other and scraping two nice thin lines right next to each other in the soot."
] | [
"On a similar note, you could do a ",
" \"slit\" interference patter, by just shining a laser past a hair. Just hold one across the top of a laser pointer.",
"For extra credit, use the interference pattern to measure the width of the hair.",
"Edit: I always manage to have at least ",
" typo in any of my p... | [
"Not quite the same, but ",
" Will produce a nice interference pattern. See ",
"for example here",
"."
] |
[
"My Brain is odd, anyone know what it is?"
] | [
false
] | null | [
"Hello,",
"We can’t advise you about this here."
] | [
"Whoops, my apologies, what would be a good place to post this?"
] | [
"You should discuss it with your medical professional."
] |
[
"Transporting P. Chrysogenum samples?"
] | [
false
] | null | [
"It would be easier to simply FedEx them than trying to bring them with."
] | [
"But then I will have to fill out similar paperwork for FedEx, no?"
] | [
"PPQ 526 permit.",
"And here's where it starts.",
" Unfortunately, you need a Level 2 account, whatever the heck that it. Might be free.",
"Probably best to contact the USDA directly (APHIS PPQ), and see if you need one for fixed samples."
] |
[
"Why do so many archaegenetics and population genetics studies only seem to use mtDNA and yDNA, and not autosomal DNA?"
] | [
false
] | *archaeogenetics | [
"mtDNA and Y chromosome DNA are the two pieces of the human genome that do not undergo recombination every generation. Essentially, they don't get reshuffled like everything else does. So, the mtDNA you get from your mom is exactly the same as your mom got from her mom....plus any mutations that have occurred. So, ... | [
"To be brief, it's because they are thought to be relatively easy to understand as they represent a single uniparental lineage that doesn't recombine. Further, especially for mtDNA, it is much cheaper to genotype or sequence than whole genomes.",
"Uniparental lineages, in particular mtDNA, have problems though th... | [
"In addition to the other answers you got here, for ancient genetics the main reason mtDNA is most common is because its much easier to recover from historical or ancient samples. There are thousands of copies of each mt chromosome per cell compared to only 2 copies of each autosomal chromosome, so each mtDNA gene ... |
[
"How do some fabrics \"keep you cool in the summer and warm in the winter?\" Or, is this just an advertising gimmick?"
] | [
false
] | null | [
"As this is a very specific question, and relies largely on which product you are talking about, could you provide a link to a specific product you are wondering about?"
] | [
"Just googling \"Warm in the winter, cool in the summer\" gives lots of products saying this. One of the more interesting I found was a kilt company saying wool did this, since it was a natural material. Of course, the reasoning is a common fallacy, but is there anything to such a claim? How hard is it to make some... | [
"Thermal energy storage in general, and phasechangematerials (PCMs) in particular, have been a main topic in research for the last 20 years, but although the information is quantitatively enormous, it is also spread widely in the literature, and difficult to find. In this work, a review has been carried out of the ... |
[
"When some animals become an Alpha or leader of the pack they undergo physical changes (silverback, baboon) how does the animals body know it's the leader?"
] | [
false
] | ok so I've always wondered how exactly the animals body knows it's the leader of the pack, head honcho, alpha etc. what causes the changes (hormones?) but more importantly how does the animals body know this is the case? edit: Seems I was incorrect about silverbacks, but I'm sure I've seen animals where the alpha looks... | [
"They don't undergo physical changes; I'm not sure where you're getting that from. ",
"All adult male (over 11 years old) gorillas are silverbacks",
". "
] | [
"Queen Naked Mole Rats secrete a hormone that represses the metamorphosis of other females into queens. When the queen dies, many females begin to change into queens, the first one to fully change begins to secrete the repressor hormone, causing the other females to revert to their original state."
] | [
"To add some details: Gorillas acquire silver coloration at age 12-15 yrs (depending on subspecies) regardless of their social status. The chart in ",
"this paper",
" lays out the age range of silver coloration in the different subspecies.",
"However, in other species there can be socially driven effects. Bab... |
[
"What causes diarrhea? Specifically why and how is a virus causing the body to expel massive amounts of water?"
] | [
false
] | Im in pain, distract me with science | [
"There are 4 mechanisms of diarrhea. Osmotic, permeability increased, secreting and abnormal motility (peristaltic)",
"All of them can coexist, and in an inflammation, they usually do, but those are the mechanisms of diarrhea.",
"TLDR:",
"Specifically in regards to the virus, it probably will replicate in ent... | [
"Certain viruses and bacteria have the ability to activate ion channels that are part of the normal mucosa in the gut. When these are constitutively activated you lose lots of electrolytes and with that, water osmotically follows causing the diarrhea and dehydration."
] | [
"Consitutively is a new word for me.",
"\nFilters. (biochemistry, of a metabolic process) At a constant rate regardless of physiological demand. adverb."
] |
[
"I was just wondering what forces are at play in a bicycle..."
] | [
false
] | So I just finished my last year of High School (holy crap) and I have this burning question which has bothered me since I was about four: how does a bicycle stay up? Now, through two years of physics study, I have learned that the bicycle is in a state of equilibrium. I know that the body balances the torque in the le... | [
"A bike is upright if the ground reaction force balances all the other forces the bike experiences: gravitational, aerodynamic, gyroscopic, intertial/centrifugal. There's no simple answer other than understanding balance of a device on a surface under gravitational pull traveling through air.",
"Center of mass is... | [
"The gyroscopic action of the wheels is almost unimportant. Hardly the \"main force.\""
] | [
"The main force that keeps a bicycle balanced is the turning of the wheels which act as a gyroscope; the faster they spin the easier it is to balance since the wheels want to stay in there current orientation (vertical) and they will stay vertical as long as the forces that tilt the wheel (gravity/center of balance... |
[
"If I increase my vocabulary will I increase my IQ?"
] | [
false
] | null | [
"IQ is essentially just a standardized test score, and just like any test you'll get better results by studying for it. Most IQ-tests are composed of analytical and visual-spacial problems, and I don't think memorizing vocabulary will help you with those.",
"Whether IQ tests correspond to intelligence is another ... | [
"This response is mostly true. If the \"IQ\" you are talking about is the overall score from a psychological assessment measure such as the Weschler Intelligence Scale for Children--4th Edition or Weschler Adult Intelligence Scale (These are commonly used measures by psychologists for assessing cognitive ability),... | [
"Well, do they?"
] |
[
"Philosophers, what is your opinion on Christopher Langan's Cognitive Theoretical Model of the Universe? (link)"
] | [
false
] | null | [
"We don't take philosophy questions in ",
"/r/askscience",
". I suggest you submit to ",
"/r/askphilosophy"
] | [
"that explains why there was not a philosophy tag, i apologize!"
] | [
"no worries."
] |
[
"Can you build muscle mass on your face with the right exercises just like you could with your biceps and thighs etc.?"
] | [
false
] | null | [
"Yes, absolutely. ",
"However, the chances of you actually causing a visible change are pretty small. One of the few exceptions to this are dedicated boxers/fighters. Mike Tyson, for example, use to chew entire packs of gum at once to strengthen his jaw muscles, and if you look at pictures of him at his prime c... | [
"you can definitely build your jaw muscles by chewing on tough things or springs. You can get better control of your facial muscles by practicing expressions, although I don't know if they get more massive or not."
] | [
"Interesting. Would that be better or worse for wrinkles?"
] |
[
"Does blocking our eye vision for long periods of time stops melanin production?"
] | [
false
] | Can melanin production be stopped if something like a eyepatch blocks the eye vision for several weeks? People who doesn't take sunlight for some time have whiter skin than before. Can this apply to the eye color as well? | [
"No, because melanin is a skin pigment produced in response to sunlight (specifically UV light) striking the skin. One cannot get tanned from simply looking at the Sun, so wearing an eyepatch will not affect melanin production. Melanin production is based on genetics and exposure to sunlight."
] | [
"I know it was a little difficult to understand, but OP was talking specifically about the melanin in the iris of the eye.",
"\nBasically he is asking if everyone would have blue eyes if they were locked in a basement for a long time...."
] | [
"Eye color is determined by a variety of ",
" as well as structural aspects of the iris. ",
"Isn't melanin the primary pigment you are describing here?",
"melanin production in the eye and in the skin occur by two different mechanisms and have two different purposes. Thus, wearing an eye patch for an extended... |
[
"If spinal damage can cause paralysis, how can quadriplegics have functional organs?"
] | [
false
] | [deleted] | [
"Organ function is not necessarily dependent on central nervous system stimulation. Many organs are controlled through complex feedback loops that depend on various factors in the bloodstream, for example. Other organs such as the GI tract have a 'separate' ",
"nervous system",
" that partially regulates its ... | [
"The vagus nerve is not safe from damage it just does not course with the spinal cord. An injury to the neck can transect the spinal cord without any damage to the vagus. Thus, parasympathetic innervation to the heart, lungs, gut, etc. is intact. Until you get to the distal large intestine where parasympathetic inn... | [
"You are assuming that someone with a spinal injury has a total transection of the spine. This is not usually that case. Usually the spinal injury is partial. The spinal cord has several pathways (\"tracts\") with different functions, such as motor, sensory (touch), position sense, vibration, temperature. ",
"So ... |
[
"How does the Axiom of Regularity prevent a set from containing itself?"
] | [
false
] | [deleted] | [
"First, let's answer your title question. Let ",
" be a set. Then {A} is a set by axiom of pairing, and the axiom of regularity says that there must be some element of {A} that is disjoint from {A}. But the only element of {A} is A. So regularity says that A is disjoint from {A}, which implies A is not an element... | [
"Re-read it yourself. Is A assumed finite, perhaps implicitly? "
] | [
"A is an arbitrary set."
] |
[
"Does antimatter have an equal form of electricity, or would it operate differently?"
] | [
false
] | null | [
"The antimatter versions of ordinary matter particles have the opposite charge, for example electrons are negative but positrons (the antimatter equivalent) are positive. The charges still obey the same electrical laws as the charges of ordinary matter, and an electric circuit made from antimatter would behave the ... | [
"Weak interaction is not invariant under charge conjugation. It couples only to left-handed fermions and right-handed anti-fermions."
] | [
"Weak interaction is not invariant under charge conjugation. It couples only to left-handed fermions and right-handed anti-fermions."
] |
[
"Why are certain chemical substances addictive and some are not, some are highly addictive and some are mildly addictive?"
] | [
false
] | I was reading an article about how Marijuana was so much better than alcohol and one of the arguments the article made was that Alcohol is an addictive substance whereas Marijuana isn't. I also know that when it comes to Psychoactive substances there is a spectrum of addiction, MDMA isn't addictive while Cocaine is hig... | [
"Fascinating question! First, let's avoid the pitfall of failing to define our terms. People use \"addiction\" to mean a lot of stuff, and even standard definitions don't line up perfectly. What it means to me is compulsive, chronic use of a craved substance despite harmful, where tolerance develops with repeated u... | [
"I have some major issues with this answer.",
"First off, the evidence very strongly does NOT suggest that dopamine release is pleasurable or rewarding. The current evidence appears to indicate that the firing rates of VTA dopaminergic neurons convey information about reward expectancy and/or changes in reward e... | [
"I have some major issues with this answer.",
"First off, the evidence very strongly does NOT suggest that dopamine release is pleasurable or rewarding. The current evidence appears to indicate that the firing rates of VTA dopaminergic neurons convey information about reward expectancy and/or changes in reward e... |
[
"Is there any empty space in the circulatory system?"
] | [
false
] | So is every blood vessel in a closed circulatory system completely filled with blood at all times - or are there times where there are empty spaces where no blood resides at all? Is the heart constantly full of blood - or does it have some empty space? When thinking about the circulatory system, I always imagined blood... | [
"The heart, unless contracting, is full of blood as well as the circulatory system. If by \"empty space\" you mean that there would be a void where the circulatory system component had literally nothing, that would be a collapsed vessel, which is a problem. This is why when you are injured, you bleed from any inj... | [
"If by \"empty space\" you mean that there would be a void where the circulatory system component had literally nothing, that would be a collapsed vessel, which is a problem.",
"Maybe a bit nitpicky, but that's not necessarily the case! Body veins can have variable amounts of blood volume inside them depending on... | [
"The heart is never depleted of blood even after contraction, there will always be residue in the shape of endsystolic volume after ejection. The above post is not entirely correct, I'll write a reply shortly."
] |
[
"If you place a tree that normally experiences seasons in an artificial environment without seasonal temperature changes, will it keep its leave year round? Will this be detrimental to it?"
] | [
false
] | null | [
"When I lived in the tropics I noted that deciduous trees would still shed but would grow back their leaves pretty well immediately. Thar said, I am sure a botanist would be able to give you a better answer. Plants have been grown in glass houses for centuries."
] | [
"Is that a dedicated shedding phase or single leaves that fall off here and there pretty much continuously? What determines the lifespan of a leaf?"
] | [
"My original reply was about deciduous trees, So yes it is a one off event annually, the big difference with what happens in cold climates is that the deciduous tree grows its leaves back pretty well immediately. You might say a nap rather than dormancy."
] |
[
"What is the critical mass of gas required for it to stick together in deep space due to gravity and not disperse due to diffusion?"
] | [
false
] | null | [
"So, while FuzzyDarkMatter does have a pretty strong answer to this as is, I think I want to add that this is a well-studied problem in physics. In fact, like most things, we have a name for it: the ",
"Jeans instability",
"! This is a simple equation which tells you what the balance is between hydrostatic pres... | [
"There is no single answer to your question. The atoms in the gas has a certain average kinetic energy determined by the temperature. If the temperature is too high, the kinetic energy per atom is so large that the gas will not be gravitationally bound. Roughly this is what happens when supernovae go off in a a gal... | [
"I have written a post a few months ago in ",
"r/Physics",
" about just this, where I derived the size of a Jupiter-like planet in terms of fundamental constants (link: ",
"https://www.reddit.com/r/Physics/comments/8zagwp/the_size_and_mass_of_jupiter_in_terms_of/",
").",
"In a nutshell, dense low temperat... |
[
"Can your circulatory system become dependent on compression garments?"
] | [
false
] | [deleted] | [
"I guess another way of putting my question would be \"Does long-term use of compression (like compression socks all day every day) cause your system to establish homeostasis that would then be thrown off if you stopped using compression?\" It's my understanding that, even though the treatments are used differently... | [
"I'd say in the long term, probably yes. \nJust like wearing a bra tells your breast supporting tissue it doesn't need to work to its full potential and becomes weaker, same thing happens with those tissues in your leg. But it may not be enough to have an impact on overall circulation, and may not be irreversible.\... | [
"That does clarify things. Thank you! (And as an ESL teacher, I hereby give you an A on this writing exercise. ⭐💯)"
] |
[
"[Biology] Does irreducible complexity have any merits at all?"
] | [
false
] | Of course this pertains to evolution. Are there any examples of a "new" complex feature evolving from random mutations and/or natural selection since our study of evolution? Or does our knowledge of DNA make this a worthless argument plagued by over simplifications. | [
"So far, no. No one has found an irreducibly complex system.",
"Using irreducible complexity is an argument from ignorance. You are basically saying, \"I can't think of a way this complex system could have evolved, therefore it could not have evolved.\" It's about as arrogant as you can get."
] | [
"No because all life is a product of evolution. Whether we know the exact steps of a certain path of evolution is irrelevant."
] | [
"Well, if that's your reasoning, sure. But that's a bit of a red herring. The argument I quoted above is what the IC community says (and yes, I have known several of them. I was in their camp for a period of time).",
"But the reasoning you quoted is not the reasoning anyone I know uses in regard to evolution; typ... |
[
"Did birds and animals like squid or octopus develop beaks seperately, or do they share a common ancestor?"
] | [
false
] | null | [
"They developed them separately. Current knowledge is that birds evolved from small dinosaurs, who had normal toothed jaws. This theoretically happened around the ",
"mesozoic era",
", which started around 250 million years ago.",
"Squids and octopi, on the other hand, are evolved from earlier forms of mollus... | [
"I can't get too in-depth about structure.",
"A bird's beak is made of keratin, which is a protein, whereas a mollusk beak is made from a mix of calcium carbonate and protein (the same substance as the shells of their mollusc relatives like clams, snails, and oysters."
] | [
"Convergent Evolution at it's finest! Beaks are super useful for many different situations like obtaining food or burrowing into something"
] |
[
"Is there a theory for or a way classifying errors that occur only sometimes?"
] | [
false
] | Within the little programming experience I've had it generally seems that either theres an error in my code and it will compile or it wont. I know that then there are run time errors or exceptions that can occur when a possibility isn't accounted for. Furthermore I know that in C you have to free up memory after its us... | [
"Aside from amoralnihilist's answer, which was mostly adequate, there is something else to consider:",
"Are these really just a coffeed out programers who put a > instead of a >= hidden somewhere in 1000 lines of code ",
"Maybe, but that wouldn't be the whole story...",
"or is there something about complex, m... | [
"Senior developer here.",
"I have seen problems that appear infrequently (observed/reported in less than 1:100.000 cases) or that are extremely hard (or impossible) to reproduce in a controlled environment; they're extremely hard to fix because of the lack of information about the conditions under which a problem... | [
"TL;DR you can never guarantee your program is correct",
"It's not as simple as that, though (I realize that is your TL;DR). It's not that it is always correct, I think he is asking about it being deterministic, behaving the same way every time with the exact same input. He isn't realizing that what constitutes i... |
[
"Is there an actual label to the \"shower principle\"? Is this phenomenon explained/researched at all?"
] | [
false
] | I heard the term "shower principle" on a TV shower recently and have been curious to learn more about the actual phenomenon. It's basically when in you've been stuck on a problem and the solution presents itself to you in the most benign of settings (like while taking a shower). What is the basis of this? Has any res... | [
"My only guess would be that a lot of people tend to shower first thing in the morning. That would make it the first time they revisit the problem that day. There is some evidence that our unconscious works on problems without our active involvement and sleep/dreaming could help with that.",
"There have been some... | [
"Also anecdotal, but I've also experienced that many times with various instruments, songs, etc. I've even found that to be the case with rhythm games like Rock Band."
] | [
"The only explanation that even approaches a scientific one that I have heard has to do with the link between the relative prevalence of different frequencies of brain waves and certain mental states. Alpha waves seem to be possibly related to a state of relaxation or reflection. If certain activities lead to the p... |
[
"Will any primate preferentially choose bananas when presented with a choice of fruits?"
] | [
false
] | I'm just wondering about the whole 'monkeys love bananas' stereotype. | [
"I worked in a monkey research lab at one point and have also worked with great apes. Contrary to the stereotype, bananas aren't always the most-preferred treat. I used to bring in a variety of different fruits to the Rhesus and pig-tailed macaques to see what they liked best, and they all had different favorites. ... | [
"I think monkeys are stereotypically paired with bananas because both bananas and (many) monkeys happen to live in tropical climates. ",
"I have it personally from Mike Tomasello (a famous cognitive scientist and primatologist) that \"There is nothing so horrible that a chimp would not do it for a grape.\""
] | [
"It is true, I work with chimps and after they taste a grape for the first time they become obsessed. Cooked white rice is also a wonderful treat. "
] |
[
"How to compressed files (.rar, .zip) work?"
] | [
false
] | I just don't understand them. I download 1MB of files, unpack it using a program like WinRar, and suddenly I have 2MB of files. How can a program like WinRar use 1MB of input to find the correct 2MB of output? Try to keep it at least a bit simple, I don't know a terribly large amount about computers. Thanks! | [
"The file is scanned for patterns, and then a substitution system kicks in. ",
"Lets say that 1010101010101010 is found 100 times in the code of the file.",
"\nThen all we do is say A = 1010101010101010, so I store A and its value in a database; and now I've reduced the size of that information from 16 digits ... | [
"It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us,... | [
"417 bytes -> 267 bytes",
"$ echo \"It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of ... |
[
"My physics teacher told us today that photons and light have mass. Everything I have read so far has said photons are massless? Can anyone clear this up?"
] | [
false
] | null | [
"Photons indeed do not have rest mass. I think your teacher meant to say momentum rather than mass. Light has momentum but not rest mass.",
"Explanation link: ",
"https://secure.wikimedia.org/wikipedia/en/wiki/Mass%E2%80%93energy_equivalence#Massless_particles"
] | [
"You can calculate a relativistic mass: ",
"http://www.weburbia.com/physics/photon_mass.html",
"This is however an out of date way of defining mass. Relativistic mass is really the same as energy so you are calling the same thing by two different names."
] | [
"Ask him to show you a photon that's not in motion. Light always moves at ",
" relative to any observer. The idea of a \"motionless\" photon is meaningless. It really does sound like your teacher is confused about how photons can have momentum but not mass. In which case you should refer him to AskScience's favou... |
[
"Why is carbon dioxide the gas we use to make drinks fizzy?"
] | [
false
] | [deleted] | [
"It dissolves very easily, and is ridiculously easy to obtain. Carbon dioxide is produced as a side effect in many processes, one of them being the brewing of alcohol, so you don't need any real effort to obtain it."
] | [
"CO2 is a byproduct of fermentation(yeast eat sugar and produce CO2 and ethanol), so beer, champagne, and other alcoholic carbonated drinks get their carbonation as a matter of course, so long as the last stages of fermentation occur in a sealed vessel. ",
"There are some natural springs that produce carbonated ... | [
"Ever tasted a really stale carbonated drink? That's what you would get if you used, say, nitrogen. Aside from the fact that nitrogen wouldn't dissolve that well, it would taste bland because it would lack that slighty stingy taste you get in a carbonated drink. These drinks, whether it's just sparkly water or a co... |
[
"Is there some biological reason that rabbits and other small animals wait to cross the street until i'm 3 feet from them in my car?"
] | [
false
] | null | [
"For anyone that hasn't heard of the term \"tharn\", it's a word from the ",
"Lapine language",
" used in Richard Adams' book ",
"Watership Down",
". I also wanted to post the links because it's a story about a group of rabbits, which is very fitting for the original question. Nice reference."
] | [
"For anyone that hasn't heard of the term \"tharn\", it's a word from the ",
"Lapine language",
" used in Richard Adams' book ",
"Watership Down",
". I also wanted to post the links because it's a story about a group of rabbits, which is very fitting for the original question. Nice reference."
] | [
"I don't know about the darting out, but I can speak a little to the freezing. First, it is interesting to think about the results of a conditioned fear task. Take a rat in a ",
"skinner box",
", and turn a light on. The rat will not do anything. Briefly electrify the floor, and the rat will jump. Now, tur... |
[
"Can we vaccinate against things like snake venoms?"
] | [
false
] | I'm mid microbiology class and we're on immunity. Obviously we talk about vaccines and it's nice and straight forward. Dump dead viral bits into the body and memory cells and antibodies get made, done, easy. But snake venom is just an enzyme, which is just proteins, so is it possible to make a preventative vaccine for ... | [
"In principle, yes. Anti-venoms are just purified antibodies for a particular venom. The problem with doing this practically is the response time. A Mamba will kill you in about 20 minutes, that means irreparable damage in much, much less time. Your immune system doesn't stand a chance."
] | [
"Pretty much. It's worth noting that all venoms have lethal doses meaning that there is some small quantity of any venom that your immune system can handle, it's pretty much just a question of whether it can deal with the amount delivered before you die. ",
"I'm not sure, but I'd also expect that simply covering ... | [
"The snake venoms are not ‘just enzymes’. Basically, they are in major mass not enzymes. In many cases they contains three-finger neurotoxins (inhibitors of various neuroreceptors, acting much quicker than any immune system response - just see Naja neurotoxin II or bungarotoxin or mentionned mamba’s toxins). Or var... |
[
"How many of the 118 elements on the periodic table are located on our planet and how many do we suspect exist outside of our world?"
] | [
false
] | I'm just curious, do we suspect there could be thousands/millions of unidentified elements within our universe or are we confident that we've identified most of them? Also, we are constantly searching the universe for potentially inhabitable planets (i.e., oxygen, h2o rich). Do we know if there are elements similar to ... | [
"We've discovered all the naturally occurring elements. New elements being discovered are highly unstable, artificial elements that are made in particle accelerators. There are almost certainly no more stable elements to be found. Unless there's another intelligent race playing with particle accelerators somewhere,... | [
"We've discovered all the naturally occurring elements.",
"To add a bit, what made the Periodic Table such a valuable tool back in the day was its ability to ",
" what properties undiscovered elements would have. Made it easier for scientists to find those elements, since they could ignore energy levels, atomi... | [
"Thank you for taking the time to respond. ",
"I'm curious to know, of all elements essential to Human life, and those that we currently use in technology (you've mentioned lithium, so my mind immediately thinks lithium-ion batteries), have we reached a ceiling with regard to our advancements using elemental prop... |
[
"How difficult would it be to genetically engineer poison resistant plants, such as monsanto and others have, but license the genes as open source?"
] | [
false
] | Instead of trying to fight big money through legislation, the idea is to remove the need to sign contracts. I personally would rather see poisons removed from agriculture, but if we are going to use them anyway... And while we are on the topic, what about engineering crops for traits that are actually useful, such as r... | [
"Developing the strains would of course take a lot of time, money, and luck.",
"However the bigger hurdles probably involve ",
"IP law",
", dealing with regulatory agencies, and marketing/distribution.",
"Determining whether something infringes a patent requires a lot of lawyers, as there are a lot of paten... | [
"There is a growing DIY-Bio scene.",
"If you're interested in that kind of thing you might like subscribing to the DIY-bio google group.",
"http://groups.google.com/group/diybio?pli=1",
"there's lots of discussion about these issues. "
] | [
"Engineering plants with resistance to pesticides requires that you have a gene that confers resistance to said pesticide. If you have that then it is pretty easy to get the gene into the plants. After you PCR the F1 generation and find some homozygous/heterozygous plants you can simply keep mating until you have a... |
[
"Is molten glass also molten sand?"
] | [
false
] | A has made me aware of a planet where 2,000 Fahrenheit glass rains sideways or something similar. My thought process then shifted to realizing this glass would likely be in a liquid state much of the time it flies around in the winds. This mental image then made me ask myself "Why didn't they call it molten sand?" So i... | [
"Sand is a grain size definition, not a material definition- specifically a grain of material between 0.064mm and 2mm in diameter. It can be made of all sorts of things, but usually primarily it consists of Silica,( i.e Quartz ,from which glass is made) feldspar and small rock fragments. In tropical places there is... | [
"In a geological sense, yes, pellets of rubber 1mm in diameter would be considered sand when observed in a geological setting. I doubt if you made a pile of 1mm diameter rubber pellets people would call it sand (no idea what they'd call it tbh) but geologically, yes it'd be sand.",
"And yes, saying molten glass p... | [
"Exactly the explanation I was looking for.",
"So basically the key is the Silica/Quartz? Glass is reformed Silica (and I assume other material varying with the glass being formed). Thus it would be more accurate to say that the planet that prompted this question has high concentration of molten Silica on it's su... |
[
"Why does viewing infrared light through a CMOS camera allow it to be seen?"
] | [
false
] | A CMOS camera is sensitive to lower frequency infrared light, but what is elevating the frequency of the light into the visible spectrum so it can be seen on a screen? I would expect either the display to not be capable of displaying this light or the viewer to not be able to see it. My question is directed primarily t... | [
"CMOS pixels (and CCD pixels) are sensitive to a whole range of EM frequencies, infrared included. They cannot distinguish colors themselves, rather they rely on filters (like a ",
"bayer filter",
") to only allow a certain color to be recorded by a certain pixels. If the infrared light is bright enough to ge... | [
"I understand we aren't truly seeing infrared, my question is more to the EEs that may be able to explain at what point in the image processing the conversion happens."
] | [
"This likely explains why the color shows up whitish, because the IF light is leaking past multiple (all) filters.",
"Exactly what I was looking for. Thank you!"
] |
[
"Fragile telescope mirrors and launching them into space?"
] | [
false
] | We all know that during launch there's immense vibrations and pressures on human occupants, but when launching something like Hubble, or James Webb, or we could even go with Curiosity, how is it these vibrations aren't just destroying these mirrors that presumably are extremely fine-tuned and fragile? In my immature mi... | [
"Telescope mirrors aren't as fragile as you might think. There's a 2.7 m telescope in Texas that was shot (yes, shot with a handgun) several times. The operators of the telescope just covered up the holes and kept on going. Telescope mirrors are much thicker than you'd expect and have support systems that ensure th... | [
"i would also assume that the one in texas doesn't have a weight budget though, so i think that the frame and support system for a space telescope will face many more technical challenges than a ground based one. Also, while a hole in the mirror (as long as it didn't shatter) doesn't matter much much to a telescope... | [
"The Harlan J. Smith Telescope",
"\"The telescope was the victim of an act of vandalism in February 1970. A newly-hired worker suffered a mental breakdown and brought a handgun into the observatory. After firing one shot at his supervisor, the worker then fired the remaining rounds into the Primary Mirror. The ho... |
[
"Can someone clarify the relationship between relativity and electron orbitals?"
] | [
false
] | video (from a YouTube channel I frequently enjoy watching) seems to use the idea that electrons orbit a nucleus in a fashion as an explanation for how relativistic effects cause a lower than expected melting point for mercury. I'm no chemist or physicist, but I remember being taught, and the wikipedia article seems to ... | [
"The Bohr model is indeed false, and electrons don't 'orbit' the nucleus in any way. An orbit is a trajectory, and the classical notion of objects following precise trajectories is just fundamentally invalid in quantum mechanics, because the uncertainty principle dictates that position and momentum can't simultaneo... | [
"Well, depends on what you mean by 'computational perspective'. Most quantum chemistry books are about solving these equations, but they don't usually include any code or algorithms, and very little (if anything) about the numerical methods at all. The bulk of the work and approximations are physics and pure math, ... | [
"It's the nuclear stability that causes heavy elements to decay, but it's true that relativistic effects are more significant as elements get heavier. Below the fourth row or so, calculations without any relativistic corrections are largely useless, and you need increasingly accurate ones as you go farther down. ",... |
[
"Is the global rise in cancer cases due to better detection techniques of the modern sciences or due to anthropogenic reasons?"
] | [
false
] | null | [
"We can't answer this authoritatively, precisely because there was no comprehensive screening and detection in the past. Direct historical evidence is scant, as most cancers are soft-tissue cancers where the evidence rots and disappears relatively quickly. A few pieces of historical evidence show us that cancers d... | [
"Increases in cancer are a sign of a healthy society.",
"Cancer is almost entirely a disease of the elderly. People who get cancer have survived to become elderly. If you want to nearly eliminate cancer from your society, bring back smallpox and yellow fever, let tuberculosis and HIV spread unchecked and untreat... | [
"What do you think about the studies showing that the consumption of animal products also affects the cancer rates in industrialised countries?",
"My English is not that good. Please overlook that."
] |
[
"Why are some of the earliest cave paintings therianthropes (animals turning into humans)?"
] | [
false
] | Some of earliest human art (32,000 BC) are depictions of therianthropes, and I was wondering what the reason could be. | [
"Anthropologist here: we just don't bloody know. All we know about the people who painting those images is that, well...they painted those images. The incomplete record of the past is what makes archaeology so fascinating and frustrating at the same time. Most of the big questions are unanswerable. All we can reall... | [
"Worth adding that, if we're talking about paleolithic art in Europe at least, therianthropes are really really rare - most of the time it's just plain animals that are drawn. And surprisingly few humans, too! (although I don't know if that's the case around the world - just Europe.) You definitely get the feel of ... | [
"By the way, I find some of the more famous therianthrope paintings you're referencing incredibly haunting",
"Could you please give examples?"
] |
[
"Why are testicles considered a gland and ovaries are organs? Or what is the difference between a gland and an organ?"
] | [
false
] | null | [
"An organ is a bunch of tissue that's generally connected, and works together to serve a function. Doesn't all have to be the same type of tissue: eg, the heart is an organ, but there's muscle, fat, nerve, connective tissue, etc etc.",
"A gland is a type of organ that makes stuff (generally fluids, often hormones... | [
"they are both glands and organs. ",
"An organ is just a body structure that serves a function",
"A gland is an organ that serves its function by excreting a substance that have effects else where outside the organ. ",
"If the substance is directly secreted via a collecting system it is an exocrine gland like... | [
"A gland is defined as a body tissue that releases a hormone. A hormone is defined as a molecule that is released by one tissue, travels through the blood or other medium, and acts on some other tissue.",
"The testis release testosterone, a hormone, that causes multiple effects on many distant tissues (secondary ... |
[
"If space is a vacuum, why do astronauts need insulated suits?"
] | [
false
] | I was just reading a recent AskSci and this intrigued me. Also if you were to float without a suit, what would be the detrimental effects, and how fast would you get radiation poisoning? | [
"Radiant heat transfer doesn't require a propagation medium. At body temperature, you are giving off infrared photons."
] | [
"I may be wrong, but I doubt it's an effective mechanism. Generally when we make a laser, the laser mechanism produces heat and needs to be cooled itself. Heat isn't ",
" energy, it's also about entropy, and my instinct is that a laser is too \"organized\" to be an effective heat emitter. I mean think about how h... | [
"According to ",
"this estimate of the radiation dose rate",
" in interplanetary space, you would never get acute radiation poisoning. Radiation poisoning starts around 5 Sv over a very short time period, and the unshielded dose estimate in space is less than 1 Sv per year."
] |
[
"Recently there's new milk being marketed here as A2 casein milk. They claim normal (A1 casein) milk is dangerous and can trigger diabetes, heart disease and even autism. Is there any real evidence to support their claims?"
] | [
false
] | null | [
"According to ",
"this",
" EFSA study....",
"EFSA has carried out a detailed review of the available scientific literature that addresses possible health effects of β-casomorphins and related peptides, and in particular β-casomorphin-7 (BCM7), a peptide sequence present in the milk protein β-casein. A few stu... | [
"Thanks muchly for the link. I found a transcript from a news report on the issue in which the vast majority of professionals interviewed voice agreement with the EFSA findings. ",
"http://www.abc.net.au/7.30/content/2010/s2866747.htm",
"*edited: clarity"
] | [
"Are they making more money from the \"New Milk\"?",
"Yes? Then of course it's all about money."
] |
[
"Will eating too few calories really prevent or hinder weight loss? If so, what's occurring biologically that makes this happen?"
] | [
false
] | During my research on fitness, I've found a lot of information about "starvation mode," or some other state that your body enters when you're not eating a sustainable amount of calories, which prevents you from losing weight efficiently. On most fitness subreddits, it seems like people think this doesn't actually happe... | [
"Starvation mode happens when you're actually starving, as in, haven't had enough to eat for a long time. Even then it's barely significant:",
"http://en.wikipedia.org/wiki/Starvation_response",
"On average, the starvation response of the individuals after isolation was a 180 kcal reduction in daily total energ... | [
"I think too much emphasis is put on this. Most dieting for weight loss is mild dieting with only a relatively small reduction in caloric intake. I'm skeptical that this has any major effect upon metabolism (except for mild weight loss).",
"The physiological changes associated with starvation occur, not surprisin... | [
"Ah, now ",
" makes sense, thank you! I always thought it seemed a little dramatic to call it \"starvation mode\" when I've just eaten a couple hundred calories less than normal o.o but it's petty logical that weight loss would subside under those conditions"
] |
[
"Can an object ever reach actual terminal velocity?"
] | [
false
] | My understanding is that terminal velocity is the point where an object's kinetic force is equal to the resistance it faces. As it reaches terminal velocity, it is accelerating slower and slower until... See there's the thing. If it's accelerating exponentially slower, does that mean it never actually stops acceleratin... | [
"The object asymptotically approaches the terminal velocity, as you guessed. However, this is only in spherical-cow theory. In reality, aerodynamics are very complex and involve a lot of random elements and an object will jitter about the terminal velocity, so for all intents it has been reached.",
"Also note tha... | [
"So in theory, in a completely controlled environment where there was only one axis of motion and there were no other factors to consider, it would never reach true terminal velocity?",
"That's pretty fucking crazy."
] | [
"This is the difference between talking to a mathmatician and an engineer. The math says it will never reach it, but the engineer will point out it actually does in reality. If you were to model every atmospheric particle's motion, you'd see the velocity reach the terminal velocity. But the math you're looking at ... |
[
"Does time occur from the perspective of a light beam?"
] | [
false
] | null | [
"So lightspeed from the perspective of a beam of light is infinite? I thought that c was a constant."
] | [
"For the beam, no time passes, but for an outside observer in another inertial system it takes time for the beam to get somewhere. Its relative to the system you are observing from. That is why the theory is called the theory of relativity.",
"A light clock gives a nice picture of these things:\n",
"This is a n... | [
"No! Sorry. I realize i was not very clear. For the outside observer, time seems to have stopped in the reference frame of the light beam. This is nicely illustrated by the time clock which is moving at the speed of light itself, so it will never \"tick\". For the photon itself, time passes completely normal in its... |
[
"If the frequency of a cat's purr is shown to accelerate healing of bone, muscle, tendon and ligament tissue, and increase bone density; and if a cat's purr is at or about the same frequency as a diesel engine; how come long-distance truckers don't have awesome bones?"
] | [
false
] | [deleted] | [
"List real sources.",
"As someone that knows a little about bone physiology, this sounds like complete bullshit."
] | [
"A cat's purr is comprised of more than just a single frequency, as is a diesel engine, as are most other sounds. A cat's purr doesn't sound much like a diesel motor now, does it?"
] | [
"A diesel engine produces far more than a single frequency."
] |
[
"When I'm boiling a pot of water, the steam is not terribly visible, but when I turn the heat off, steam BILLOWS out of the pan. My question: if there is suddenly less heat, why is there suddenly MORE steam?? Why isn't it the other way around?"
] | [
false
] | null | [
"The steam was there all along, but you couldn't see it. When you see the \"steam\", you actually see the water vapor condensing back into water. When the heat is on, the steam had more energy and doesn't condense as much, so you see less."
] | [
"maybe he should boil a less energetic water ... like VitaminWater?"
] | [
"I'd have said 'had a higher temperature', it's more specific. And less association with people talking about energy when smoking pot, really energy an often hijacked term.."
] |
[
"In Lorentz transformations, why is gamma defined the way it is?"
] | [
false
] | Where γ = 1/sqrt(1-v²/c²). Why isn't it defined as just sqrt(1-v²/c²)? | [
"Well, gamma itself isn't anything physical. It's just a dimensionless quantity defined for mathematical convenience. So you can define it any way you find convenient. You can define it that way (adjusting the transforms accordingly) if you like. ",
"But since the term tends to always occur in the denominator, it... | [
"Yeah, that's what I would say too. Plus perhaps there is some motivation to have gamma increase as speed increases."
] | [
"Your first equation should be given with a triple equal sign. It is a definition, not an equality."
] |
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