title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Is there any electric potential difference between the planets? E.g., if Earth is ground, is Mars at 5 volts? If so, how is it measured?"
] | [
false
] | null | [
"The solid surface of Earth is at about -300 kV relative to the upper atmosphere.",
" The overall solid+atmosphere Earth is however basically neutrally charged, so this means that Earth surface is also -300 kV relative to \"outer space\". Most likely, Mars' voltage is of the same order of magnitude but not the ex... | [
"This is somewhat speculative, but in the ionosphere, free electrons would have a velocity more than sufficient to free them from the Earth's atmosphere, which might potentially be able to make the Earth's (if by Earth we're talking planet and atmosphere together) net charge positive. However, it may be that such a... | [
"Well, since Earth has an active magnetosphere that repels a large portion of the solar wind and Mars does not, it seems logical that the surface of Mars receives more charged particles than Earth's does. Would this difference result in a slightly higher net charge on Mars?"
] |
[
"Did our ancestors acquire most of their food from hunting or gathering?"
] | [
false
] | And is there a consensus in the scientific community on a rough percentage of how much came from from hunting and how much from gathering? My intuition tells me gathering would be much more common because its easier (no running around using lots of energy), less dangerous, more reliable (because berries and nuts will g... | [
"Question: would you count scavenging as hunting or gathering?"
] | [
"There is no one answer, Eskimo's ancestors' diet was very different from, say, Bushman's."
] | [
"http://en.wikipedia.org/wiki/Hadza_people#Subsistence",
"This might be of interest to you, it doesn't mention the actual hunting/gathering ratio though."
] |
[
"Ionizing Elements, what causes it in the system?"
] | [
false
] | Learning about Ionizing systems and components in particular to how they are applied in the sciences such as in ICP-MS. My question is in two parts but the latter part is what is more important to understand. Part 1: In what characteristics to plasmas vary? Like in liquids there's viscosity, conductivity, etc. I'm inte... | [
"Typically when you're characterizing a plasma the most important parameters are the electron temperature and the charged particle density, in addition to the characteristics of the gas. [Edit: the characteristics of the gas are important because the degree of ionization is usually very low in an ICP, so you're dea... | [
"I work on plasma in an astrophysical context, so I can't talk about the engineering side of things, but I can talk about the physics of it in general.",
"The short answer is that plasma ",
" ionised gas, by definition. Ionisation is when some (or all) of the electrons have been removed from the atoms by some p... | [
"I explained this in more detail in my top-level comment, but what you're describing is a thermalized plasma, which is not the type of plasma used in most engineering applications. Engineering plasmas are low-temperature, where ionization is caused by electron-atom collisions, not atom-atom collisions. The applied ... |
[
"Will we eventually reach a point where computing power is so great that encryption will be meaningless?"
] | [
false
] | [deleted] | [
"If we just assume that computing power rises, and disregards advances in other fields (algorithmics, math etc.), the answer is a clear no. Additional computing power allows for brute forcing larger keys, but it also allows for using longer keys. And the increase in required computing power for using a longer key i... | [
"Possible, but unlikely as cryptography methods are at least currently being developed ahead of computing ability. Quantum computers are purported to be able to break through most modern cryptography methods. Modern encryption relies on the difficulty in factoring large numbers, which is a problem easily solved b... | [
"Quantum computing also allows for encryption such that intercepted messages are always discovered by changing the entangled wavefunction, making essentially a type of encryption always impossible to hack. "
] |
[
"What importance is it, that we know where the water on the moon came from?"
] | [
false
] | I've read a number of papers about the origin of water on the moon but one question that has persisted to evade an answer to through out, is how and why do does research get funded? What important implications does answering such a question, as to what is the origin of water on the moon, hold? Will it benefit humanity ... | [
"What important implications does answering such a question, as to what is the origin of water on the moon, hold?",
"Well, it's likely that the moon's water came from the same source as earth's water. But the moon's water is in a more pristine condition, more suitable for research. So we may be able to answer som... | [
"So if I'm understanding you correctly, understanding whether or not the water was derived from cometary bombardment or volcanic degassing of the lunar mantle may be able to tell us how much water is present on/in the moon or at least it's a start? And, from there we can see why or why not it may be feasible to exp... | [
"If you know how it got there, it's easier to find it once you get there.",
"And water on the Moon, from the Earth, is really expensive, so it makes some sense to expend a lot of effort to extract the Moon's water once you're there.",
"Which is all to say, it's good tactical planning for a Moon base."
] |
[
"Do any other organisms have the same color awareness that humans do?"
] | [
false
] | I noticed the other day while watching an Anole at work that while he had in fact turned brown against the wood where he was sunning himself, he was significantly darker than the wood itself. It was easy for me to pick him out against the wood, but would it be so easy for, say, a Red-Shouldered Hawk or some other anima... | [
"http://en.wikipedia.org/wiki/Color_vision"
] | [
"some animals see into the infrared or ultraviolet. I dare say that they have even greater color awareness than we."
] | [
"Cool article. Especially liked how mantis shrimp have 12 spectral receptors."
] |
[
"To the astronomers of Reddit: When will the sun rise over down-town Toronto (date-wise) when viewed from a point from Hamilton Beach? Due to my latitude, will this event even occour?"
] | [
false
] | I'm attempting to photograph a sunrise over Toronto either from Hamilton Beach or Burlington. You can regard this as a point along an imaginary line formed by the coordinates 43°15'12.88" N 79°45'34.31" W and 43°19'06.93" N 79°48'03.59" W. For reference, downtown Toronto is located at approximately 43°38'55.41" N 79... | [
"Never going to happen.",
"You need a sunrise azimuth of at least 42 degrees according to a quick measure in Google Earth.",
"In June, the sunrise azimuth at Toronto is ",
"no better than about 57 degrees",
".",
"You can do the maths yourself according to ",
"this equation",
". "
] | [
"Shoot. Thanks for the help guys."
] | [
"Google Earth lets you simulate this as well, right down to the terrain and 3D buildings. I use it all the time in landscape photography planning."
] |
[
"What happens under/in the skin when you scratch and itch vs leaving it unscratched?"
] | [
false
] | So this morning during my early AM BM I got a particularly annoying itch near my mouth. I didn't want to touch my face without having washed my hands so I had to wait until I was done. This got me wondering what happens during an itch, when we scratch them, and what happens like in my situation where I had to let it s... | [
"As an addition to this, is there a major difference between a \"surface\" itch and an itch that feels \"deeper\", and does not go away as easily as the other? Sometimes not even being able to itch it away."
] | [
"i heard somewhere its the small amount of pain from the scratching which does something in your brain that stops the itch, im sorry i dont know any more info."
] | [
"If, when scratching, you remove the source of irritation that caused the itch in the first place, then it of course goes away. If the source disappears on its own before you have a chance to scratch that itch, then the itching sensation would cease. However, we humans have a great ability to obsess about such thin... |
[
"Where do magnets draw their power from?"
] | [
false
] | So I'm not sure if this is a really stupid question but I'd like to know where magnets draw their power from. They create pushing and pulling forces somehow, but never seem to run out of this force, so where does this endless source of energy come from? It seems that there should be a way for us to use this unlimited e... | [
"Where does a table get its power from?",
"Realize that magnets push and pull in the same way your hand doesn't go through a table.. it is merely that the table and your hand have very weak forces so you dont feel anything until its \"touching\"(actually magnetically repelling), whereas with a magnet you can see ... | [
"Whatever energy you extract using a magnet must first have been stored in the magnetic field as a potential. It's the same as with gravity: if a falling object gains kinetic energy from the fall, it is losing potential energy."
] | [
"Maybe a simpler way to express ",
"/u/readams",
"'s analogy is this: in order for something to ",
" it had to be raised up to begin with; if something already falled, you have to work to raise it back up. ",
"So if two magnets have already pulled themselves together, you have to work (which expends chemica... |
[
"What determines how severe will allergic reaction be?"
] | [
false
] | There are people who can as much as lick a peanut and die from severe allergic reaction. I have pollen allergy, sometimes walk all day with runny nose which sucks, but I don't tend to die from that. I guess that amount of allergen doesn't matter so much, because for some people life threatening amount peanuts is much l... | [
"The immune system is really complex with regard to allergic reactions or autoimmune responses. Generally allergic reactions occur because a normally harmless antigen (a molecule found in pollen or cat hair or peanuts) elicits an inappropriate immune response. ",
"When these antigens are recognised you'll general... | [
"You may not get an answer on this one, because the real answer is that nobody knows. ",
"Duke university did a few experiements on Oral Desensitization to peanuts that are interesting. The goal was to reduce the severity of the initial reaction by gradually increasing the stimulus.",
"My son is deathly allergi... | [
"Thank you for your answer.",
"My first askscience question and it's about something mankind doesn't know yet :) I guess I should make my PhD in immunology and sort it out then."
] |
[
"I don't want a tan. I want to be paler. Is this possible?"
] | [
false
] | null | [
"Avoid exposure to the thermonuclear sky furnace. Don't resort to chemicals."
] | [
"Well...\nYou could also just take the first google link ;)\n",
"http://www.ehow.com/how_2222314_become-pale.html",
"\nSo the thing with the loofah (Point 2) sounds legit, I don't know about 4.\nAnd as MandatorilyMatutinal stated... I wouldn't go for 3 (chemicals)"
] | [
"I'm was skeptical of exfoliating your skin, but I think it's viable method. Upon investigation, Melanin, responsible for skin pigmentation, is produced by melanocytes at the bottom most layer of your epidermis. Melanin is shipped to keratinocytes, which produce 95% of the cells in your skin. ",
"From my understa... |
[
"Why do animals (including humans) lick their wounds?"
] | [
false
] | null | [
"Saliva has natural antiseptic in it, which helps keep the wound uninfected. Also it can remove bits (like gravel from a graze) which could harbour infection."
] | [
"Better than leaving dirt and grime and foreign bacteria in there. Your body would be used to the bacteria in your mouth."
] | [
"Would this be an effective method for humans, knowing humans have filthy mouths?"
] |
[
"Volume of Matter in Universe"
] | [
false
] | null | [
"So, this is actually a really hard question. First, there's the issue of how much matter you want to crush together. We don't know how much matter is in the Universe. There is no easy, direct way to find the mass of just the matter we can see. However, thanks to the way spacetime seems to behave (measured to be co... | [
"Think of it more this way: stars start as clouds of dust and gas. Towards the middle, there's no net acceleration (only mass inside a given surface contributes to the gravitational force acting on particle on the surface). Towards the outside of the cloud, there's a huge force developed, because stellar dust cloud... | [
"Well, again, it's depends on the situation. If the star that forms is a supermassive red supergiant (let's through all the super's in there), it can actually burn out into a black hole pretty quickly as larger stars shine brighter and burn faster. For white dwarfs and neutron stars, the accretion process is a much... |
[
"How does your body know your bladder is full?"
] | [
false
] | null | [
"There are nerves that tell the the brain when the bladder is stretched and full. You start to get the urge at 1/2 to 2/3 of the maximum capacity."
] | [
"This is due partly to mechanoreceptors on the bladder wall. The relfex arc required for micturation is stimulated by mechanoreceptors, which respond to the stretching of the tissue. The mechanoreceptors sense bladder fullness and send impulses to the sacral level of the spinal cord with bladder filling. "
] | [
"You have two spincters leaving the bladder. First one you don't control, it's based on pressure from above, including other organs pressing on the bladder. Second one you control. Both have feedback but (I think) you couldn't tell the difference since potty training. "
] |
[
"Is there a limit on how big a lake can be?"
] | [
false
] | null | [
"The question is vague. Do you mean is there is a physical limitation to how large a lake can be? Or do you mean in terms of nomenclature, i.e., how big (or small) is a \"lake\" before it is something else? For the latter at least, there is no formal size definition of a lake vs something larger or smaller."
] | [
"No. A lake is a body of water surrounded by land. Some are very small, one can swim across them easily. Some, like Lake Superior are huge, bigger than many countries. ",
"Even the world's largest inland body of water, the Caspian Sea is defined as a lake, despite the name. ",
"On Earth, the only bodies of wate... | [
"So if the strait of Gibraltar closed it would be the Mediterranean lake for all intents and purposes?"
] |
[
"What determines the boiling and freezing points of a substance?"
] | [
false
] | null | [
"Long story short (in case someone else can't give a more technical response) is that every single molecule is attracted to other molecules of its kind in a pure solution of it.",
"That being said, some molecules are really good at attracting each other (things that are solid at room temperature) and other things... | [
"The boiling and freezing points of certain substances are based on the molecular interactions between the atoms of that substance. So let's take something easy like boiling water for example. As the water starts to boil, what's happening is the heat from the stove is transferring energy into the water exciting tho... | [
"the physical state (basically) ",
"solid - liquid = either freezing or melting",
"liquid - gas = either vaporizing or condensing ",
"gas - plasma = either ionization or deionization ",
"(there are others, but they are more obscure) ",
"this varies by the substance - water is usually used as an easy examp... |
[
"How massive does a planet have to be to reliably retain Helium in its atmosphere?"
] | [
false
] | The Earth purportedly doesn't. Uranus, at 14.5 times Earth mass, apparently does. What's the "critical mass" at which Helium can be reliably (not absolutely) retained? As an aside, I just realized that, whenever we see those animations of spiraling dust clouds forming the solar system, the dust clouds spiraling in to f... | [
"No definite mass - too many variables influence loss from atmospheres: Temperature - how fast the He atoms move. UV from it's star kicks light atoms out. So does solar wind, how quickly depending on speed, density and whether the planet has a magnetic field. Night and day will likely have an effect, as it does on ... | [
"No, the gravity is the important factor in this case. The presence of other gasses has little or no effect, other than possibly slowing the rate of abrasive removal from solar wind."
] | [
"The answer has to do with how that atmosphere forms...which has to do with the gravity."
] |
[
"In cooking, how do thickening agents work?"
] | [
false
] | I spend a lot of time cooking, and as such, I make a lot of stews, gravy, soups, things that require a thickening agent. I generally use flour or corn starch mixed up with a bit of warm water, and I know that it's what thickens up my stews...But why? It's something we're taught to do in cooking, but like many things,... | [
"http://www.youtube.com/watch?v=VC-Pj9wAHsQ&t=4m30s"
] | [
"Very simply: starches and other thickeners are very long molecules which when combined with water create gel or better - slime like substances because they are tangled and keep the water from escaping in a normal liquid fasion."
] | [
"Hmm, that's really cool, thanks =)"
] |
[
"What is our body trying to accomplish by making us hiccup?"
] | [
false
] | I do not hiccup.. Not in the traditional sense that is; I don't make that sound. Different question: do you know how to burp on command? Well, I use the same contraction to allow stomach gas out. The agitation of the hiccup is still there, and I very consciously acknowledge it by "trying to burp". That's why I found a ... | [
"I don't think anybody knows. Wikipedia has decent coverage here:",
"https://en.wikipedia.org/wiki/Hiccup#Evolutionary_causes",
"They mention 2 potential causes, the first one sounds a bit more believable than the second but none of them sounds like a slam dunk argument. ",
"To save you a click, here's the fi... | [
"I find it interesting that you suggest hiccups may be designed to eliminate gasses from the stomach. I have noticed adult drinkers of alcoholic beverages can often get hiccups. Obviously carbonation of these beverages would trigger this gas elimination. ",
"It is a common bar tenders trick to cure these hiccups ... | [
"Bread often causes hiccups in me, especially dry bread. But simply drinking water clears them up."
] |
[
"Magnetic fields and electric fields are manifestations of the same phenomena. They are inherently related. Is there a duality that exists between the gravitational field and something else? Thank you."
] | [
false
] | null | [
"Magnetic and electric fields were historically thought of as totally separate things, and the distinction has stayed around since. In the case of gravity, there is an analogous ",
"\"magnetic part\" of the force",
". But since there wasn't a whole historical treatment of this force as a separate thing, it's ju... | [
"It’s somewhat accurate, but it often leads people to believe that ",
" electric field can be fully transformed into a purely magnetic field in some frame of reference, and vice versa. But that’s not correct.",
"There are two independent invariants that can be constructed from the electromagnetic field tensor, ... | [
"On a tangential note, I've sometimes heard magnetic fields described as simply a consequence of relativistic transformations of electric fields; in other words, \"electric forces in a moving frame.\" Would you say this is accurate?"
] |
[
"What is the difference between geoid and ellipsoid geometry and why is it important in GPS and cartography?"
] | [
false
] | I'm having real trouble understanding the difference between these two definitions and their uses in cartography. I have read what I can find online but I haven't really got any closer to what the difference is. | [
"The biggest issue between the two as they relate to cartography is in the vertical.",
"The ellipsoid is the reference used by GPS to establish height. It is important to intuitively understand that the ellipsoid is a first approximation of the Earth, and thus has very little to do with any physical characteristi... | [
"Perfect, thank you very much."
] | [
"Excellent summation."
] |
[
"If someone is over weight or obese through adolescents or teen years can this stunt puberty and physical maturity development?"
] | [
false
] | null | [
"Actually, it's quite the opposite! And not the opposite too! So basically, yes and no. Confused yet? ",
"Childhood obesity has actually been implicated in ",
" sexual maturation, at least in females. Its a bit more complicated than that though, because puberty is a pretty complex set of hormonal changes. ... | [
"So in basic terms it can actually cause earlier onset on girls but hold it back on males? \nIf this is correct can that \"holding back\" cause males to have any lasting negative effects such as not reaching a full physical potential or delayed sex drive and smaller muscles? And on the contrast can early puberty fo... | [
"Kind of...\nIn females, it looks to be a mixed bag: they may develop breasts sooner but have menses later (or no effect on menses, more study is needed). In males, they do seem to have a delay. But remember, puberty is more than just the outward physical changes and is a whole huge set of hormonal changes regula... |
[
"What did schizophrenics worry about before the invention of cameras and listening devices?"
] | [
false
] | null | [
"The case of ",
"James Tilly Matthews",
" is considered to be the first fully documented case of paranoid schizophrenia. A book about him was published in 1810.",
"The Wikipedia article has a detailed description of his beliefs. Here is an excerpt:",
"Matthews believed that a gang of criminals and spies ski... | [
"Now that’s exactly the type of answer we all want to see. Thank you"
] | [
"That's one very common (esp. media/pop culture) delusion, the family of which is persecutory delusions. And it's not nec. just devices -- individuals with persecutory delusions often feel like they're being watched or followed by people, or entities more generally (the government is tapping my phone, etc.).",
"I... |
[
"Why is it so hard to find a cure for \"the common cold\"?"
] | [
false
] | null | [
"'Medicine'"
] | [
"'Medicine'"
] | [
"'Medicine'"
] |
[
"What about heat makes it appear to bend light when I'm driving down the highway on a hot day?"
] | [
false
] | null | [
"The density of air changes with temperature. Light travels at different speeds through the same medium at different temperatures because of this density change. When the light moves through different densities it gets bent. It's basically the same as a prism just not as clean and defined. Did that make sense?"
] | [
"Also, its not so much about the heat as it is the turbulent transfer of heat very close to the surface where centimeters above the surface the lapse rate is incredibly high."
] | [
"Ah, I was not aware of that. Thanks"
] |
[
"How can relatively soft animals survive the crushing pressure of the Mariana Trench while still maintaining their shapes?"
] | [
false
] | null | [
"Deformation from pressure results from pressure gradients across a barrier. In the case of deep sea life there is no gradient, that is, the pressure inside is the same as outside. Therefore there is no deformation.",
"There is some biologic effect from the pressure, as described in this paper ",
"High-pressu... | [
"As long as they are able to equalize their swim bladders as they rise, nothing",
"Deep sea critters don’t have swim bladders. OP’s question is about the Mariana Trench which goes down to 36,000 feet. But even beyond a few thousand feet, fish have no swim bladders. Fish from shallower depths which do have swim bl... | [
"As ",
"/u/Wrathchilde",
" said, deformation from pressure comes from pressure gradients across a barrier. In other words, the reason deep-sea fish aren't squished is because they have the same pressure internally pushing out. Since you live your entire life under 1 atm pressure, you can't survive 10 atm pressu... |
[
"How much energy does it take for a person to escape the moon's gravity?"
] | [
false
] | null | [
"If I answer your question strictly, the Moon's escape speed is 2380 m/s. Assuming a person is 70kg, 1/2 mv",
" = 198 MJ = 55 kWh.",
"However for space applications we rarely ever think about energy this way. Rockets are terribly inefficient, so we must calculate this in terms of propellant. Also we will (obvio... | [
"Well, it really depends on how much mass. The person, ship and fuel would need to be considered. In the case of the fuel, you are ejecting spent fuel as you go, so it becomes a bit more involved. On top of all of that, you might want to consider the efficiency of your craft, depending on what you want to do with t... | [
"The escape velocity on the moon is about 2500 m/s (compared to the Earth's, which is about 11,000 m/s). To find the energy, you would need to know the mass of the object, from which you could calculate the force required to accelerate the object to that speed.",
"Then, multiplying the force times the distance o... |
[
"'Biology' At what point would an invasive species be considered integrated into an ecosyste?"
] | [
false
] | It obviously varies from individual ecosystems, but I've always wondered if destroying "invasive species" actually hurts ecosystems based on how long it's been in the environment. | [
"An excellent example of this is the dingo in Australia. Commonly thought of as native, but actually naturalised. It was brought over by the aboriginal people around 60 000 years ago. It plays the role of large apex placental mammal, of which Australia has no others. It is integrated into the predator/prey relation... | [
"Humans are the only invasive species that is also an apex predator?"
] | [
"Humans are the only invasive species that is also an apex predator?"
] |
[
"My 5th Grader needs an expert for her report. Can I post her q`s about plastic?"
] | [
false
] | Thanks for your attention. My very ambitious daughter is doing an "expert" report for school and she was hoping for a real expert opinion not just me and google. We called all of our friends and relatives for some help, finally I told her I would post on reddit. She typed out some questions she has. I will post what ... | [
"Good Evening!",
"I'm a professional chemist who works in the polymer industry, I finished my PhD in organic chemistry about ten years ago, perhaps I'm expert enough? (Of you'd like further credentials feel free to send me a message.)",
"There are many different types of polymers that are made by man and many t... | [
"I think i can field the plastic - biology questions so I will quickly throw in my 2 cents...",
"Plastics provide a novel habitat for some species and allow some organisms to travel farther and more frequently then they normally be able to do. After all, there is a huge amount of plastic being dumped in the ocea... | [
"I already have done an ",
"AMA",
". "
] |
[
"How does a pro level power lifter/strong man' strength compare to wild animal's such as a chimpanzee, or a bear?"
] | [
false
] | Is it anywhere even close, or are animals really just that much out of our league? | [
"Chimps are roughly twice as strong as humans:",
"http://rspb.royalsocietypublishing.org/content/273/1598/2177.full.pdf",
"Unfortunately this experiment only showed jumping ability. The long-touted study by John Bauman in the 20's that showed chimps to be 5 times as strong as humans was later shown to be flawed... | [
"Generally, it's a given that chimpanzees are stronger than humans. ",
"The leading theory is that human muscles and the associated nerves are wired more for dexterity and chimpanzee muscles more for strength. ",
"Basically, humans have more small motor units (nerves activate a smaller number of muscle fibers a... | [
"Bears are much stronger either way. It's hard though to answer really because the terms of strength are not well defined. Are we talking about bench press, force of a punch, force of a tackle, explosive strength, squatting ability? A chimpanzee has a much more natural strength used for lots of climbing and jumping... |
[
"If you drilled a hole halfway to the center of the Earth, what would be the downward acceleration due to gravity?"
] | [
false
] | I'm having trouble understanding at the moment, especially as it pertains to non-point masses. For instance, I've been told that the gravitational potential energy is equal to GMm/r where the variables stand in place for the gravitational constant, the massive body, the other body, and the distance between the two. I'm... | [
"I remember asking this question in high school, and my teacher showed me that, after you've descended into the earth, the gravitational field strength is linearly related with the distance to the centre. In other words, if you drill halfway to the centre, the acceleration due to gravity would be about half as it i... | [
"Assuming that the earth's density is constant, of course. This is an OK assumption at best (see: ",
"http://arxiv.org/abs/hep-ph/0105293",
"), but fails completely for more centrally condensed objects like gas giants and stars."
] | [
"Clearly. =\\"
] |
[
"Are there an infinite amount of colours?"
] | [
false
] | Right, it's been quite a few years since I did Physics at school, but the colour of visible light depends on its frequency and wavelength, right? As there are an infinite amount of numbers between any other two numbers (such as 2 and 3, for example), could there be an infinite amount of possible EM frequencies? Between... | [
"There are some really good answers to this question [here](",
"www.reddit.com/r/askscience/comments/jptf6/are_there_infinite_colors_rather_can_wavelengths/",
"), and the short answer is yes, there are infinitely many colours. For the really lazy, here's RoboRollCall's excellent reply:",
"What you want to kno... | [
"Damn I wish she would come back. She always was so articulate and elegant in her posts."
] | [
"This seems to hit more on the philosophy of science side. Here's a question for you: are there an infinite number of colors if I can only \"see\" a finite number of them? Even with the most sensitive equipment in the universe, you could only ever detect and report a finite number of observed colors.",
"I know th... |
[
"We are said to be 10% human and 90% bacteria - where does the bacteria come from?"
] | [
false
] | Also where does it reside - is it just in the gut and on the skin, or elsewhere too? I am also curious about how the uterus remains sterile during gestation and how much that prevents bacteria from the mother being transferred to the child. Thank you! | [
"Also it should be noted that the 90% figure is ",
" only, as bacterial cells are tiny in comparison to human tissue cells. They compose only small percentages of our total weight and volume."
] | [
"Also it should be noted that the 90% figure is ",
" only, as bacterial cells are tiny in comparison to human tissue cells. They compose only small percentages of our total weight and volume."
] | [
"Yeah, it's called \"breast milk\". Breast milk actually contains oligosaccharides that aren't of any nutritional value strictly to the baby, but are food for various strains of beneficial bacteria."
] |
[
"Is there a term for the self organizing of these reservoir covering balls? How does this occur?"
] | [
false
] | What causes the balls to organize into neat rows as they are in this photograph? I encountered that imagine in an earlier thread about covering reservoirs and thought it would be too off-topic to discuss in the thread itself. Thanks in advance! | [
"The general name of the process is ",
"self-assembly",
" and happens on all scales, for example, you can even see similar assemblies of ",
"nanometer sized objects",
" or even atoms in crystals. The reason such an organization occurs is because this arrangement, called ",
"close packing",
" allows the ... | [
"Just wanted to highlight ",
"grain boundaries,",
" if you didn't already find your way there from the other links. "
] | [
"Thank you for taking the time to answer, that was great an exactly what I was looking to learn. Much appreciated! "
] |
[
"How many password guesses can be made in one processor cycle?"
] | [
false
] | I am assuming a processor running at 2.8 ghz could make 2.8 billion guesses per second, but I can't seem to find anything. I guess my Google-fu is weak. The root of my question is this. Lets say that site says your password would take X amount of time, assuming 100 trillion guesses per second, could a computer capable ... | [
"A processor's clock speed is going to give you more of a ratio in terms of guesses/sec/GHz as opposed to a solid number of guesses per second. The actual number per second will depend on the number of instructions per guess, and how many instructions per clock cycle a processor can manage. Then, you have to take i... | [
"There are a variety of ways to store passwords. A horrible setup just stores them as plaintext, which means those passwords are known the second an attack is successful. This opens users up to password-reuse attacks.",
"More commonly, a password is stored as an encrypted hash, where the stored password looks not... | [
"There are a lot of different ways a password gets checked, so there is not one answer. If you are at a login prompt at a computer, and were pumping username/password combinations at it as fast as possible, It takes many operations/cycles for the login program to compare the given password to the stored \"right\" p... |
[
"Why is the International Space Stations speed not constant?"
] | [
false
] | [deleted] | [
"This is true but it is not the whole story. That graph shows mean altitude which does fall off from atmospheric drag between burns of the engines.",
"The orbit of the ISS is not quite circular, there is a difference of a few km between perigee and apogee. As the station approaches it's apogee it's altitude falls... | [
"This is because the ISS orbits at an altitude at which it still encounters air resistance from Earth's atmosphere. This air resistance is extremely low because the atmosphere is extremely thin at these altitudes, but it does exist.",
"http://www.heavens-above.com/IssHeight.aspx",
"This air resistance causes th... | [
"[deleted]",
"\n ",
"What is this?"
] |
[
"What can the James Webb telescope see that the Hubble can’t?"
] | [
false
] | [deleted] | [
"Finer and more detailed pictures. If I'm not mistaken, Hubble can only see about 10 billion light-years (ly) away, but those pictures are kinda fuzzy, we can still collect a lot of data, but JWST is going to take MUCH finer measurements, observations, and pictures.",
" Hubble specializes in taking visible light ... | [
"Well aside from the huge scientific value (which will allow us to better understand the universe and our place in it, minor stuff like that), space telescopes are also a very important part of generating public interest in space exploration."
] | [
"Well aside from the huge scientific value (which will allow us to better understand the universe and our place in it, minor stuff like that), space telescopes are also a very important part of generating public interest in space exploration."
] |
[
"Could we make a hydraulic press strong enough to metamorphosize rock?"
] | [
false
] | null | [
"Sure and we have (though they are not all technically hydraulic presses, some use other mechanisms of generating force besides hydraulics). There is an entire branch of geology, ",
"experimental petrology",
", which uses devices like ",
"diamond anvil cells",
" to generate temperatures and pressures suffic... | [
"Iirc, some labs now have diamond anvils capable of pressures on the order of terapascal to investigate processes on planets with pressure regimes greater than Earth, check out yingwei fei at the Carnegie Institute in DC.",
"Edit: Iirc this is how scientists confirmed that there is a mineral in the Earth called b... | [
"We have been making synthetic diamonds from carbon with a HPHT process (high pressure high temp) for decades. These are 5 GPa at 1500°C. It is not the only process for making diamonds though, CVD is another.",
"https://www.youtube.com/watch?v=azSnoaGCcig",
"It's crazy, it's a cubic press that compresses a c... |
[
"What is the difference between a rechargeable battery and a regular one? why can't we recharge normal batteries?"
] | [
false
] | null | [
"There are lots of different kinds of batteries, so when you say \"normal\" batteries, I'm not exactly sure what you mean. But, that's neither here nor there.",
"Simplest answer is the chemicals used in the batteries are different. Most \"normal\" batteries are based on a chemical reaction that can only really ... | [
"Okay, I'm going to assume we're talking about AA size batteries and their family. You can get this form factor as a Li-ion battery chemistry nowadays, but they're not terribly common. Usually someone considers a normal battery to be one that uses the Zinc-Alkaline chemistry, whereas the rechargeable batteries in t... | [
"In regards to the standard AA battery: When we see a \"normal\" battery leak acid, is it because the battery is dead and the gas buildup might have caused a rupture?"
] |
[
"Could the speed of light be broken by creating a whole bunch of vectors layers like a Russian Matryoshka doll and then moving them all at once?"
] | [
false
] | null | [
"No. If I understand your argument, you're adding a lot of velocities together. However, for each velocity you can only add the rapidity (artanh(v/c)) algebraically. Specifically what's happening is that you're \"boosting\" into the second frame, measuring a velocity, \"boosting\" into that third frame, etc. You ca... | [
"Special relativity. There are so many ways to look at this, let me try another. In relativity the ",
" ",
"addition of velocities",
" is (v1+v2)/(1+(v1*v2/c",
" )). When the speeds are so much less than c, the formula is ",
" v1+v2. Gallilean relativity (simple velocity addition) is only an ",
" truth;... | [
"Could the speed of light be broken…",
"No.",
"…by…",
"No.",
"…creating…",
"No.",
"Are you getting the point here? The speed of light isn't arbitrary. It's as fast as it's possible for anything in our universe to move, or for any effect to propagate. I don't care what the rest of the sentence says, if t... |
[
"I just watched Armageddon and it got me thinking, if an apocalyptic-sized asteroid were on a collision course with Earth, does Nasa have any plans in place to destroy it before contact? Or would we actually all be screwed?"
] | [
false
] | null | [
"You wouldn't want to destroy it, you'd just end up with a big ball of sand coming at you (if it didn't reform), which would impart just as much energy onto earth, just in a different way, and still have catastrophic results. ",
"What you want is a ",
"gravity tractor",
", which will slowly deflect it. ",
"... | [
"There was actually a study on this exact topic not too long ago. Not only does NASA not have a plan, we as a species don't even have the capability to destroy an asteroid of that magnitude.",
"Study: ",
"http://phys.org/news/2012-08-armageddon-looming-bruce-willis-bother.html",
"Skeptic' Guide to the Univer... | [
"I meant warning, you're correct. I typod or got autocorrected. ",
"But funding would also be a factor. "
] |
[
"Why can you hold your breath for longer if you exhale at the end?"
] | [
false
] | I've experienced this while diving, it feels like you can hold your breath for longer, if you slowly exhale just as you start feeling uncomfortable. Even holding breath with empty lungs feels easier than holding in as much air as you can. Does this have anything to do with increasing amount of co2 in your lungs, or why... | [
"The limiting factor in holding your breath is not a build up of CO2, rather it is the impulse of the diaphragm to contract.",
"http://www.scientificamerican.com/article.cfm?id=the-limits-of-breath-holding"
] | [
"Your observations are not corroborated by this study, and others, on breath holding. ",
"http://ep.physoc.org/content/54/2/129.short",
" ",
"\"The influence of lung shrinkage on the breath holding time was studied in three normal males. The rate of shrinkage was increased two to three fold either by slow e... | [
"was studied in three normal males.",
"Would love a slightly larger sample group, and better info on exactly what was being measured. Me, and the OP, both experience a different result when we try the experiment ourselves. That puts us on nearly a similar sample size."
] |
[
"Why is the Theory of Evolution not a Law?"
] | [
false
] | null | [
"No problem, take care now."
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"/r/askscience",
"Also consider looking at ",
"our FAQ",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"guidelines",
"If you dis... | [
"This comes up a lot, I suggest you search the sub for some threads on this. \"Laws\" are generally either historic terms or they refer to very specific relationships, usually mathematical ones. Coulomb's law or Hooke's law are examples of this.",
"In science, \"theory\" is the highest praise an idea can get. It ... |
[
"What fuel is burning after the detonation of a thermo-nuclear device?"
] | [
false
] | Setting off a H bomb produces a mushroom cloud, and it's often filled with fire seconds or minutes after the bomb is detonated. The reaction's over, so the bomb isn't producing energy. What is burning? edit: remove repetition | [
"It's oxygen and nitrogen in the air.",
"https://en.wikipedia.org/wiki/Effects_of_nuclear_explosions",
"The red/orange color seen here is largely due to the ionization of air molecules, predominately produced by the preceding fireball's intense heat, The Oxygen and Nitrogen naturally found in air, and generally... | [
"Although NOx compounds are oxidizers. It's an endothermic reaction, so in some sense that's the opposite of burning."
] | [
"The reaction's over, so the bomb isn't producing energy.",
"Not to say that this is the cause of the light you're describing (I don't know), but a significant amount of energy is released after the explosion from beta decay of the fission fragments, about 7% of the total. This is the reason that most reactor me... |
[
"Is there a theoretical limit to how small a file can be compressed and still be fully recoverable?"
] | [
false
] | [deleted] | [
"I'm guessing you mean ",
" for the ",
" compressed file? In that case, the short answer is yes, it's the ",
"self-information",
" of the file -- a concept strongly related to ",
"Shannon entropy",
". ",
"However, that's not the full answer, since the result of your compression is actually a function ... | [
"Yes, in the worst case, compression cannot guarantee to reduce the size What you are describing is the pigeonhole principle: ",
"http://en.wikipedia.org/wiki/Pigeonhole_principle",
" ",
"For your second question, you'd probably be interested in Huffman encoding. It's optimal in the mapping strings to stri... | [
"Yes, in the worst case, compression cannot guarantee to reduce the size What you are describing is the pigeonhole principle: ",
"http://en.wikipedia.org/wiki/Pigeonhole_principle",
" ",
"For your second question, you'd probably be interested in Huffman encoding. It's optimal in the mapping strings to stri... |
[
"Why is it that music that is perceived louder, sounds better?"
] | [
false
] | Loudness war is common term in the music industry. It is the practice of compressing the dynamic range of a song so the overall volume can be raised to a consistent high level. This is common with mainstream music but something that most artist believe kills the art. What is the scientific reason on why we prefer music... | [
"Im going to be generalizing here, but typically radio (non digital) isn't high fidelity. Not only does it lose fidelity during transmission, but it gets played on low quality speakers (boom boxes, crappy car stereos in noisy cars, bad pa systems), and and finally reaches indiscriminating and aging ears. ",
"When... | [
"wouldn't our ears get adapted to that level and null out the perceived loudness? ",
"Your ears are generally in the business of accurately perceiving the world, not artificially normalizing the world. If something is actually loud, you ideally want to perceive it as loud for as long as it's loud.",
"Sometimes,... | [
"It's not that it sounds better but rather it tends to be preferred by most people. You seem to be saying you prefer music with more dynamic range no?",
"It's because the majority of people like simpler more forward obvious things.",
"You have the same problem with TV and monitors. Most computer monitors and TV... |
[
"Curious Theist Here"
] | [
false
] | [deleted] | [
"It is a terrible analogy. They have reduced the problem to the point of absurdity, so any proposed solution to it seems absurd.",
"There are tons of web sites, books, and videos out there that will explain in detail why the assumptions of this argument are unrealistic. Feel free to look them up on your own. A... | [
"The analogy is dishonest because there is no selection pressure or inheritance governing paper and pen.",
"A more apt analogy might be the old 'infinite monkeys on infinite typewriters creating Shakespeare' idea, except that there's also an infinite number of humans who burn everything that doesn't look like Sha... | [
"Well put. I would only try to clarify one point you made:",
"As soon as the first self-replicating RNA strand arose, it created more like it.",
"Chances are that self-replicating RNA came into existence countless times before it had a chance to replicate for the first time. There's nearly no chance that the fi... |
[
"If a dog is separated from it's mother at birth, and reunites with her years later, will he recognize her as his mother?"
] | [
false
] | I'm wondering if a dog could recognize it's own mother based on her smell if he was separated from her at birth. | [
"And vice versa, would the mom recognize the pup? "
] | [
"You are correct about timing being important. Most animals have \"critical periods\" where certain environmental cues must be in place for it to exibit a certain behavior. These cues are response for \"imprinting\" the behavior. A goat who is not allowed to lick and nurture her young within the first couple of wee... | [
"You are correct about timing being important. Most animals have \"critical periods\" where certain environmental cues must be in place for it to exibit a certain behavior. These cues are response for \"imprinting\" the behavior. A goat who is not allowed to lick and nurture her young within the first couple of wee... |
[
"Question about tumors"
] | [
false
] | Can anybody define what exactly "tumor uptake" and "tumor-to-background ratio" values refer to? I have a very vague idea, but I'm not sure. I'm interested in tumor presence and measurement in the body. | [
"In my field, \"tumor uptake\" refers to the amount of a substance (i.e. drug) that is delivered to and retained at a tumor site. These substances can be internalized by metabolically active tumor cells, or simply trapped in the tumor space due to leaky vasculature and poor lymphatic drainage (called the \"enhanced... | [
"agreed with this, including the question of \"what are you referring to?\" OP - i think you are likely not to get a complete answer until you give a bit more info to go off of"
] | [
"I was reading into an experiment where mice grafted with human skin were injected with antibodies. The antibodies were labeled with dyes, to try and find tumors inside the mice that originated from out-of-control growth factors. The mice were checked at 24 hr intervals and the experiment article mentions that tumo... |
[
"How does Uranium Lead dating of crystals work?"
] | [
false
] | Just watching Cosmos. It's the episode about finding the age of the earth. They explain that uranium decays to lead. We know the half life of lead. So if we measure the amount of lead and the amount of uranium, we can do some maths to find the age of a sample. So far so good. But then they say that the original reading... | [
"Let's back off a bit and start from the beginning.",
"U-Pb geochronology works by using crystals of very resilient U-bearing minerals; the mainstay of this method is zircon, but some other minerals such as baddleyite may also be used.\nWhat is measured is not merely the amount of lead; the amounts of U and Th mu... | [
"Ah! Well there you go then. Glad to have been of help.",
"Also to be kept in mind that Pb-Pb is also a thing, much more complex and finnicky, and sometimes produces paradoxical results such as \"future ages\" in some settings such as Mississippi-Vally-type deposits ... . This method is not used on zircons, but o... | [
"Thank you for this. It was indeed zircon crystals that they used. It wasn't explained that different isotopes of lead are produced by the decay of uranium. ",
"And, given that they are, i don't see why they couldn't separate the different isotope levels like you suggest. ",
"It turned out that they were detect... |
[
"The sugars that makes fruits taste sweet: are they mainly intra- or extra-cellular sugars?"
] | [
false
] | E: Front page and thanks for the answers! This question came while I was eating my unripe honeydew and wondering if the amount of sugar I consume is the same while unripe vs. ripe (it has to be!) Some reading and recollection of high school biology then told me that it is mainly starch which is broken down into simple ... | [
"Intracellular, mainly within vacuoles.",
"In plant cells the vacuole occupies up to 90 % of the cell volume5. This large volume makes this organelle uniquely suited to serve as a dynamic storage compartment for various solutes and sugars represent the most abundant molecule type in the vacuole.",
"https://www.... | [
"I'm not certain but unless the composition of the sugars varies between the intra- and extra- cellular compartments I would hypothesise that there would be a negligible difference. Once you've chewed the fruit and it's inside the digestive system the components of all the fruit, including sugars, will all be relea... | [
"Whas the difference of intra and extra for how my body reacts?"
] |
[
"Why did women lose their facial hair while men didn't? has facial hair become a useless byproduct of the testosterone?"
] | [
false
] | [deleted] | [
"Biologically, it’s not going to be a “useless byproduct” so long as the Sun’s spectrum extends into the ultraviolet, which is expected to be the case for several billion years.",
"Among other functions, fur and hair protect the skin against ultraviolet radiation, which can cause skin cancer. Skin cancer is one o... | [
"So you can imagine that protection against this is something that’s likely to be strongly selected from an evolutionary perspective",
"If social custom drives most men to shave, and does so over many generations, would that affect how this trait would be selected?"
] | [
"Probably not, at this point. Medical science has advanced enough that melanomas are treatable, at least if caught early enough. Lifestyle changes also help in this regard. For example, we don't spend the entire day outdoors in the Sun, hunting and foraging. Most of us work in offices, factories, live in homes whe... |
[
"South pole: does the sun rise and set on the north?"
] | [
false
] | [deleted] | [
"There's only one sunrise and sunset per year if you're exactly at the geographic South Pole. Between those dates, the sun is either up all day or down all day. This year it rose on ",
"September 21 at 17:05, over the 102nd meridian",
". Next ",
"March 22 at 20:02 it will set over the 76th meridian",
". Bot... | [
"at the south pole, the sun rises and sets but once a year, and the point at which it sets is somewhere along the horizon, depending on how tall you are.",
"so yes it always rises and sets in the north.",
"Extending that, at the north pole, the sun rises and sets in the south"
] | [
"Also, depending on the time of year, and proximity to the poles, the sun will rise/set closer to North/South than East/West. Only between the Tropic of Cancer, and Tropic of Capricorn does the sun rise/set due East/West, and only 2 days per year at any particular latitude. "
] |
[
"Theoretically, would light shone on a 4-dimensional figure cast a 3-dimensional shadow?"
] | [
false
] | [deleted] | [
"A 4D object, with the right definition of \"shadow\" will cast a 3D one. It is a standard linear algebra fact that a projection along an axis reduces the dimension of a space by one. It might be easier to think the other way around, what is the silhouette of a 4D object?",
"The shadow of a tesseract probably won... | [
"There aren't any 4D objects either, so in your interpretation the question is meaningless. It is pretty clear OP was asking about a theoretical 4 spacial dimensions, they specifically mention tesseracts."
] | [
"you would need 4-dimensional light. What is that?"
] |
[
"If we can vaccinate chickens against salmonella, why haven’t we done the same for humans?"
] | [
false
] | null | [
"It's complicated. The vaccine targeting chickens is primarily an effort to reduce food-borne disease in humans, and it does that pretty effectively. So, we target the source as a means of prevention rather than targeting humans directly. Easier and generally safer. Bacterial vaccines are generally short-lived (6-1... | [
"not enough people are affected",
"1.35 million Americans per year have some kind of Salmonella infection. ",
"A little more than 400 deaths per year from Salmonella infection every year. ",
"Those deaths = about 0.000122% of the country's population.",
"In short - it's statistically a non-issue."
] | [
"In the UK there's less than 10,000 cases per year. That's 0.01% of the population.",
"If there's 1.35 million cases in America, that's 0.3% of the population.",
"The USA really needs to sort out food hygiene and animal welfare standards..."
] |
[
"Does the matter directly beneath an object exert more gravity on it than further matter throughout the earth?"
] | [
false
] | null | [
"Yes, if you want to split the gravitational field up into parts coming from different parts of the Earth, then because the force due to gravity drops of like 1/r",
", a kg just below you contributes more than a kg at the centre of the Earth, which contributes more than a kg on the opposite side of the Earth. ",
... | [
"So in practice no-one thinks about splitting the gravitational field up like that because this is much more elegant and efficient.",
"Well, ",
" of us think about it. In practice, no planet is truly spherical nor homogenous, and it can be exceedingly useful to think of a planet's gravitational field split up i... | [
"Newton's Law of universal gravitation shows us that the force of gravity (F) has an inverse square relationship with distance (r). This means that the closer two objects are, the greater force of gravity experienced and vice versa.\nF = G(m1xm2)/r"
] |
[
"Would it be possible for two similarly-sized planets to orbit one another while also on the same trajectory around their sun?"
] | [
false
] | null | [
"Do you mean something like the Pluto, Charon, Sun 3-body system?",
"The center of gravity of the Pluto-Charon system is actually outside Pluto."
] | [
"That was the impression I got from reading his question. I believe he is thinking about two planets that effectively share the same path, orbiting around a center point, with their gravitational pull holding them in sync."
] | [
"Gif of the system's orbit.",
"Also, both rocks are ",
"tidally locked",
" to each other; both rotate at the exact rate that they orbit each other."
] |
[
"When something like GFP is expressed in an animal such as a fish what is actually occurring?"
] | [
false
] | Is the gene for gfp being expressed in all of the host cells of the organism? If so, how is this type of genetic engineering done on a large scale throughout the organism? | [
"The number and type of cells that express GFP depends on the type of promoter that is driving GFP expression. A promoter is a segment of DNA that doesn't code for protein, but instead tells the transcription machinery whether or not to make the protein in that cell. GFP could be expressed under a \"ubiquitous\" pr... | [
"Introducing an exogenous gene into an organism is a process called trangenesis. ",
"Some transgenic animals that express GFP do express it in all cells of the body! For research, though, most people are going to hook the GFP gene onto some sort of other gene that we actually care about, and then we can just see ... | [
"Is this only viable at the embryonic stage of an organism? And could this method be used to mediate immunity to disease through genetic changes?"
] |
[
"What are eigenvectors/values and their practical application."
] | [
false
] | null | [
"Asking for a list of the application of eigenvalues and eigenvectors in the physical sciences is like asking to list the uses for nails in carpentry. It's more difficult to think of an application for which they are not important than one for which they are important."
] | [
"This for me really describes what the hell an eigenvector is in plain terms.",
"I doubt the definition from your lectures/book is substantively different.",
"It's a scalar operator.",
"Scalar operator means something else, namely an operator of the form aI, where a is a number and I is the unit operator."
] | [
"One of the most widely used mathematical concepts. The ",
"Wikipedia page",
" has quite an extensive discussion, including a large list of applications. It would be good to ask a more specific question."
] |
[
"Why are infrared waves the ones that are hot?"
] | [
false
] | If heat is the transfer of energy, wouldn't all light be 'hot'? Is it simply that the human body is most receptive to infrared light as the 'hottest'? | [
"all color photons transmit energy, if an object can absorb them. ",
"First, at around normal temperatures you experience, IR photons are the most radiated. ",
"see here",
" ",
"Second, IR frequencies correspond to molecular vibrations that are easily translated into heat by a process called Intramolecul... | [
"well, not necessarily, but in general it's easy to find organic molecules that absorb no visible light, such as polyethylene plastic sheet, clear gelatin, clear plastic bottles. These all still absorb IR because they have carbon-carbon bonds, carbon-hydrogen bonds etc. And water is clear but absorbs IR strongly ... | [
"All objects radiate in the electromagnetic spectrum. This is called \"Black Body Radiation\". Things that are above about 1000°F (798°K) glow in the visible range. An object that is heated to 1000°K will glow red. If you heat it to 5000°K it will glow yellow. ",
"Since most of the things that are giving off heat... |
[
"Best affordable microscope for home?"
] | [
false
] | To look at blood, hair, water, etc... with my son. | [
"Perhaps ",
"USB microscopes",
" are the way to go: dirt cheap and you get pictures (that you can link to in Reddit)."
] | [
"This is exactly what I was thinking. A usb microscope would be good because my son and I could look at the images together at the same time.",
"HOWEVER, I really have no clue regarding what specs to look for. Any recommendations for specific microscopes would be appreciated."
] | [
"Could do worse than go to a ",
"USBm review site",
" of which there are ",
"more than one",
"."
] |
[
"When we lose fat by exercising, where does the fat go?"
] | [
false
] | null | [
"Fat in the body is stored in fat droplets in adipocytes, which are cells specialized for fat storage. When you gain weight, it is by the storage of more fat in these cells and their expansion, not by the formation of new adipocytes. When you are \"burning\" fat, it is by the metabolism of the fat from these drople... | [
"http://www.mayoclinic.com/health/body-fat/AN01327",
"Your body converts fat to usable energy for your muscles and other tissues through a series of complex metabolic processes. This causes your fat cells to shrink.",
"These metabolic activities also generate heat, which helps maintain your body temperature, an... | [
"Vigorous exercise shouldn't result in a rate 5 to 7 times higher than normal. The minute volume we breath can increase that much, but respiratory rates above 40 are extremely ineffecient. Keep in mind we're breathing larger volumes as well, as soon as you get above 40 a minute, you're down to 1.5 seconds for equ... |
[
"When the sun eventually expands and consumer Earth, will it expand all at once in the blink of an eye or be a gradual expansion over a long period of time?"
] | [
false
] | How embarrassing... Typo in my title. I don't know how many billion years from now, but at some point in the future the sun expands. Will this be a slow process where the sun grows larger over a period of.... Some amount of time. Or will it be more a 'boom' and in the blink of an eye puff up to a larger size? | [
"Gradual process. Has to do with the expenditure of its fuel causing it to progressively expand until it collapses under its own weight. We happen to live within its potential expansion area, but the radiation, heat, and solar flares will bake the planet dry ( literally) well before we fall into its surface. ",
"... | [
"Mankind has plenty of a chance. We have ",
" billions of years to prep leaving this planet, but knowing ",
", it will all be last minute, underfunded, and more or less half-assed. "
] | [
"So slight any human won't notice a change in their lifetime. Probably for generations at a time. "
] |
[
"Can someone please answer an evolution question?"
] | [
false
] | I heard from a Christian teacher at my school that evolution is impossible because mutations can only result in a loss of complexity in an organism. They told me that new genetic information cannot be introduced, that only old information can be manipulated (either by being lost or changed into a different base pair, l... | [
"That's not true, it's possible for mutations to cause genes or chromosomes to duplicate, allowing addition of information.",
"Your teacher most likely cannot explain the results of the E. coli long term evolution experiment."
] | [
"More specifically, gene duplication allows for one of the copies to be modified with no negative effects (barring something ridiculous like the copy producing poison), because the original (or copy) is still there to produce the original chemical.",
"A long example:",
"I have gene ",
" that produces enzyme "... | [
"Well, there's no way around it: your teacher is simply presenting you with non-factual, disproven ideas. Mutations can result in duplicated or added base pairs, or even additions of entire new chromosomes."
] |
[
"Why does not not finishing your full dose of antibiotics promote the growth of antibiotic resistant bacteria?"
] | [
false
] | [deleted] | [
"If I may quote ",
"devicerandom",
" from his bestof'd post:",
"These things matter A LOT. It's extremly serious. Please, please, please do not ignore your doctor's advice on this matter. Doing so will be a problem not only for you, but for all of us. Please.",
"The huge problem with antibiotics is that bac... | [
"Yes. The point is to keep the population as low as possible while the immune system clears the survivors."
] | [
"So the TL:DR would be \"What doesn't kill them makes them stronger\"?"
] |
[
"How does blubber keep mammals warm despite nerves in the skin that sense the extreme cold?"
] | [
false
] | We've been taught since we were children that whales and other mammals keep warm using a thick layer of blubber. But doesn't the surface of their skin sense the extreme cold? Or do they have duller cold receptors? I understand how the body can be insulated by the blubber but when the skin comes in contact with icy cold... | [
"There is a tolerance system involved. Whales don't dive from land to water so their receptor have time to adjust when they enter cold water(they enter gradually). For seals, bears and other \"furry\" mammals there is an extra thin layer of air/water that gets trapped in the fur and acts as an insulating layer. Eve... | [
"As an experiment for OP, try this: get 3 bowls of water, one room temp, one hot, and one with ice in it. Put a hand each into the hot and ice one for 60 seconds and then put them both into the room temperature bowl at the same time and see what happens. Your nerves really aren't very good at sensing temperature as... | [
"Also, I believe the main role of ",
" is to keep the internal organs warm. So it doesn't really matter if you actually 'feel' cold as far as the important bits inside are warm and protected. "
] |
[
"The likelihood/percentage of HIV transmission per each coital act, enlightenment on this subject..."
] | [
false
] | I'm looking for clarification on this topic, while doing research on the subject as a whole I came across the 0.05-0.08% numbers on male-female infection rates. I cannot understand if these published numbers are numbers on the actual change of contracting HIV in each unprotected sexual encounter, or something else enti... | [
"That rate is per sexual encounter. So a woman who has vaginal sex with an infected male partner twice a week for a year has a 1-(1-.0008)",
"~=8% chance of infection. Over 5 years this becomes 34% or over ten years 56%.",
"The point is that even though the 'per encounter' rate is very low, the overall chance o... | [
"I understand, thanks. I'm a 25 year old male and for the first time ever did I bother to do some research on this topic and was kind of astonished at the actual numbers, from early on in my life I've always learned that any unprotected sexual encounter with an HIV infected person meant getting it as well... I see ... | [
"However despite all the places were it can go wrong, it'd only take a successful one to infect the individual. Those numbers are still mind boggling to me... Reading the CDC link, it's mentioned that even a blood transfusion still only has 90% chance of infecting the individual. Wondering if that particular number... |
[
"Would inhabitants of the ISS be able to see with their bare eyes if a nuclear war started on earth?"
] | [
false
] | [deleted] | [
"oh yeah, no doubt they could see it and the fires burning after.. ",
"talking about things which explode brighter than the sun.. ",
"ISS is only 350 kilometers up or so.. not very far "
] | [
"Most definitely. A nuclear fusion bomb is orders of magnitude hotter than the sun, so is much brighter. The mushroom cloud is also full of burning gas, so would be clearly visible from space. "
] | [
"Even hydrogen bombs primarily get their energy output from fission. The fusion is there mainly to release fantastic numbers of neutrons which proceed to fission additional uranium.",
"Edit: ",
"Teller-Ulam bomb"
] |
[
"Would it be possible to slow light down enough for the naked eye to see it moving?"
] | [
false
] | Light moves 66% of c in water. Would it be possible to create a liquid(other states of matter also count) in which light moves so slowly so that it's visible with the naked eye? An example: Let's say that we have a curtain of said liquid. If I stand on one side of it, and quickly am to walk to the other side, and looke... | [
"As has been said, light in a medium can be slowed down dramatically, with the most famous examples being in Bose-Einstsein Condensates (BECs). I just want to add a little niggling issue, which is that you can't see light at all take a path that isn't into your eye. Hollywood has us primed, for example, to think ... | [
"Hollywood has us primed, for example, to think we can see laser beams, but in reality the only way you can see laser beams is to be directly in its beam or if the room is so filled with crap (i.e. dust, chalk, mist, etc.) for the laser light to hit that enough light is being scattered OUT of the beam and some of i... | [
"There's no theoretical limit to how slow you can make light. Researchers have ",
"slowed, and even temporarily stopped",
" light using exotic materials such as Bose-Einstein condensates. So in principle, with this material, you could indeed walk around a piece of it faster than light can propagate through it.... |
[
"Hydrophobic Interactions"
] | [
false
] | Could someone please explain to me why hydrophobic interactions take place in terms of entropy/enthalpy etc? Cheers in advance. 3rd year MChem student studying protein thermodynamics. | [
"Here is something I remember from my basic biochemistry... ",
"Sodium chloride is readily soluble in water. What happens is that water can hydrate and stabilise sodium and chloride ions which will reduce their tendency to associate in a crystalline lattice leading to increase in entropy.",
"These ions are of c... | [
"Yep. It makes a lot more sense once you realize the extent to which water molecules have to organize around any bit of hydrophobic material. "
] | [
"This was a very helpful post and really increased my understanding. There's still one bit I don't get though - \"Hydrophobic solutes can not offer such compensation and result in small gain in enthalpy.\" Why is there an increase in enthalpy?",
"Very refreshing to have such a complex matter explained so simply, ... |
[
"Can wave functions of two particles completely cancel eachother out, in the same way as noise cancelling?"
] | [
false
] | null | [
"In regular QM? You can keep the wave-function normalized, and 0 is not normalizable. So no.",
"Another way to look at it is that the Hamiltonian is unitary, which means that you can always reverse-engineer the history of your wavefunction given it's state now. If the total wavefunction would evolve to zero, ther... | [
"In Quantum Field Theory the story is probably different.",
"He is purely asking about interference effects of particle wave functions, so strictly speaking the answer would be no. At least in the sense that a two-particle state will never just vanish everywhere due to many-particle interference (which would ulti... | [
"Yes, and this is observed in the ",
"double slit experiment",
" ",
"Note that, just like noise cancelling, you do not get total destructive interference everywhere, just at intervals."
] |
[
"Is it theoretically possible for scientists to create life?"
] | [
false
] | NOT a religious question. I'm just as much of an atheist as the rest of you. | [
"This is as close as we've gotten.",
"Of course, a case could be argued that \"life is created\" in IVF clinics, but I could be straying into a minefield with that and I mean my answer to be completely secular."
] | [
"Sure, it's just chemistry. We just don't currently understand all of it (mainly with the bio- prefix I think) and we lack the tools for precise manipulation.",
"Compared to my field (programming) it's like we're still in the ages of the ",
"front panel",
", but with half the switches missing (no control), al... | [
"Theoretically possible, but experimentally difficult."
] |
[
"Is combining two telescopes (through optical interferometry) really equivalent to having a larger mirror?"
] | [
false
] | E.g. In addition, the Keck I and Keck II telescopes can work together as the Keck Interferometer. The 85-metre (279 ft) separation between the two telescopes gives them the effective angular resolution in one direction of an 85-metre (279 ft) mirror But are there some things that a larger telescope can do - that it can... | [
"It gives you the resolution of an 85m telescope, but not the light capturing power. So a real 85m telescope would be able to take really deep images quickly."
] | [
"The combined mirrors have the same ",
" as an 85m mirror, they lose on sensitivity though due to collecting area.",
"Also, the ways that this works means that the telescope separation leads to certain spatial scales being filtered out. I'm more familiar with how this works at radio wavelengths but the general ... | [
"A larger dish could collect more light and thus detect fainter objects given equivalent sensors."
] |
[
"If two identical twins had children with another set of identical twins, would each couple's children look identical?"
] | [
false
] | null | [
"No, not unless both sets of twins were also fully inbred and homozygous. This doesn't mean \"somebody married a cousin\" - in genetics terms for model organisms this is typically defined as 20 generations of brother-sister matings.",
"Humans are diploid, which means everyone carries two copies of every chromosom... | [
"It would be the same as two people having children twice. The children will look like any other pair of siblings"
] | [
"Appearance wise they will be as likely to look similar to each other as any pair of full siblings from the same parents. ",
"Genetically, they will be as alike as full siblings, even though socially they would be considered first cousins. "
] |
[
"Why do flashing lights cause seizures?"
] | [
false
] | null | [
"The same way any form of over-stimulation causes seizures.",
"The flashing lights cause the brain send out too many brainwaves at once. This results in a seizure.",
"This type of epilepsy is known as ",
"photosensitive epilepsy",
". "
] | [
"Big misconception: everyone with epilepsy gets a seizure from flashing lights. There are many kinds of epilepsy, and many people (like me) don't get seizures from flashing lights."
] | [
"Hello, I'm a neuroscientist coming from a lab where we study and develop models of epilepsy in mice. Flashing lights tend be a very powerful pattern of stimulation as they can activate both on and off retinal ganglion cells (cells in the retina that respond to changes int the state of light). Scientists who study ... |
[
"Magnetism and Conservation of Energy"
] | [
false
] | I'm sure I'm missing something, hopefully someone can enlighten me. Here's my thought experiment: Suppose you had a wooden ramp and you rolled some irons balls down it. You put a natural (not electrically induced) magnet just under the middle of the ramp and you have the angle of the ramp set just so that the balls sl... | [
"I think I have an explanation for this one. ",
"As the ball moves across the magnet, ",
"Faraday's law",
" tells us a current is established inside the ball. The current in turn cause ",
"Joule losses",
" in the ball. ",
"So the kinetic energy of the ball is transformed into electrical energy by Farada... | [
"Not really, if his magnet is strong enough, you can stop the ball entirely. Then what? Where did the kinetic energy go?.",
"I can reasonably guarantee that magnet to soft ferromagnetic interaction only conserve energy if you take hysteresis and joule losses into account."
] | [
"ramp set just so that the balls slow down when passing over the magnet but continue down the ramp",
"But do they though? It would seem to me that the ball would speed up as it approaches and slow down as it leaves.",
"Also, I suppose you could store potential energy in the arrangement of balls and magnets as i... |
[
"Atoms of molecules share electrons unevenly. Does this effect an atom's ground state and excited state status?"
] | [
false
] | null | [
"What do you mean?"
] | [
"In molecules elections can be shared unevenly. Some atoms are more electronegative and pull more on the electrons of other atoms. My question is does this pull lead to the electron orbital expanding at all. Does this expansion of the valence electron orbital lead to atoms being in a more excited state?"
] | [
"Does this expansion of the valence electron orbital lead to atoms being in a more excited state?",
"When you make such statements about the electron configurations in the molecule, you are implicitly assuming some energy eigenstate of the molecule (most likely the ground state).",
"So the answer to this:",
"... |
[
"Animals with a \"defense mechanism\": Are these to defend an actual attack from enemies, or do they repel enemies by their sheer existence?"
] | [
false
] | The reason I'm asking is that there was a hedgehog in front of my front door and I wondered: Does it have its spikes to hurt enemies when they attack and to possibly get away, or do (at least some of the potential) enemies just don't bother because they couldn't kill and eat it anyways (and maybe learned this after a b... | [
"u/freedom_or_bust",
" mentions mutation accumulation as the limiting factor, but it's really an issue of ",
". If we assume that the venomous animal and the mimic are cousins (which is common), then parallel evolution should allow both species to have the venom. What the mimic really gets out of it is that it ... | [
"Basically it is more likely to evolve. Lets look at the coral snake/king snake situation.",
"The coral snake has essentially no predators, because of its extremely venemous bite. One king snake has a mutation. It's color patterns are very similar to that of a coral snake. None of the king snake's natural predato... | [
"Hedgehog spikes will deter predators if they can identify the spikes and associate pain with them, however, if they do not identify and associate spikes with pain, they will if they proceed with their attack (although some animals do figure out a way around the defence mechanism).",
"Some animals that avoid pot... |
[
"How exactly do hormone treatments raise/lower a man's/woman's vocal pitch?"
] | [
false
] | [deleted] | [
"This is from for MTF transitions, but false for FTM transitions. Testosterone has an effect on vocal chords (and voice) even in adulthood. ",
"See here."
] | [
"To my understanding, past puberty -- or perhaps past the point where your voice deepens -- there is no way to change the anatomy of the vocal chords other than some risky surgery. Instead those going through hormone replacement therapy train their voices to sound more feminine with varying success."
] | [
"Yes, pitch is unaffected by estrogen after having dropped in puberty as a result of testosterone in MTF. In FTM, testosterone treatment will cause the voice to drop fairly completely and permanently within a year.",
"Pitch however is only one of perhaps 10 different voice qualities of equal importance such as t... |
[
"Are there any \"evidences\" supporting the hypothesis that reality and the universe as we know it is the product of a simulation? If not, why did it become so popular?"
] | [
false
] | null | [
"Are there any \"evidences\" supporting the hypothesis that reality and the universe as we know it is the product of a simulation?",
"No. ",
"If not, why did it become so popular? ",
"Because it's a fun idea and people like fun ideas. Also the Matrix was a pretty awesome movie. But to reiterate, there is ab... | [
"And before anyone chimes in with this, the Planck length and Planck time do not support the notion that spacetime acts like discrete pixels.",
"Yep, see here: ",
"https://www.physicsforums.com/insights/hand-wavy-discussion-planck-length/"
] | [
"There is no direct evidence for this hypothesis. Even if spacetime is discrete at the smallest scale, and not continuous, this would not necessarily be evidence that the universe is a simulation. This could just be an inherent trait of our universe. To have evidence of a simulated universe, researchers would have ... |
[
"What would the first living cells have been feeding on?"
] | [
false
] | Could they have survived on dirt and air? | [
"Phosphates and hydrogen. ",
"Well, chemicals in general, but since those two are still used to power our cells today it's quite likely it was, if not the first, then the most successful energy source. ",
"Nitrates are popular, too, as is sulphur compounds found in deep sea volcanic vents. There are even bacter... | [
"Doing so is effectively impossible. ",
"Not only would it require millions of tons of organic compounds and millions of years, or more, but we have a hard enough time making sure a single metric ton of metal and electronics spending months in a vacuum subjected to hard radiation doesn't carry any ",
" microbes... | [
"We'll never truly know what the first cells where feeding on, but there are a lot of good hypotheses out there. One of best ideas involved deep sea hydrothermal vents such as those of the modern 'lost city vents', which aren't as high a temperature as other vents, and thus can be sustained over thousands of years.... |
[
"Can the geometry of currents in a moving fluid be considered fractal?"
] | [
false
] | null | [
"There are definitely circumstances where self-similarity in turbulence has been observed. The assumption of self-similarity is crucial to the Kolmogorov theory of turbulence (see ",
"here",
"). This theory of turbulence is based only on the ideas of self-similarity and dimensional analysis. It works quite well... | [
"Eventually thermal equilibrium between the fluid and its surroundings will be reached. It may limit itself a little bit while the fluid heats up (assuming the turbulence is driven by external work), but the viscosity will never be zero. "
] | [
"So, in Newtonian liquids, the decrease in turbulence at smaller scales is self-limiting, being that viscosity decreases when heat is applied?"
] |
[
"Holes in The Theory of Evolution"
] | [
false
] | null | [
"The word \"theory\" when used in the context of science, ",
" mean the same thing it does in everyday speech. It's meaning is closer to \"an explanation of how something works\" rather than \"a guess.\""
] | [
"Well put. We cannot directly observe what happened to life on Earth over the millennia so we cannot say anything about it with absolute certainty, but there is an overwhelming amount of evidence for evolutionary theory. "
] | [
"I'm not a scientist, but it is worth noting that gravity is a theory too."
] |
[
"What is the function of thallium in smartphones (or generally in electronics)?"
] | [
false
] | Hi reddit, after my last question I read a bit more about materials in tech, and it's absolutely fascinating. I thought it was all just plastic and silicon, but there is a whole world of strange stuff out there. I wanted to know what you can find in a phone and found those two cool papers: They both ground down phones ... | [
"It's a guess but thallium photo cells doesn't mean solar panels. They could just be simple light detectors for screen brightness or the camera. No idea if you would need that amount though.",
"Also thallium can be used in camera lenses and specialist glass so that is another potential use"
] | [
"Thallium is the moast common element to use when doping glass cylinders to form GRIN lenses. Lithium works, but not quite as well.",
"For the GRINs of it: Instead of shaping the glass into a lens, it is possible to vary the dopant levels in a lens to bend light, but keep the faces of the lenses flat. This way,... | [
"Most phones use some type of infrared sensor (proximity, face detection, camera) which use thallium selenide in the sensor to be sensitive to infrared wavelengths. ",
"It's possible that it may be used in some of the lenses for the cameras as thallium can be used for certain types of lenses/optics, but I'm not 1... |
[
"If mitochondria and chloroplasts are/were their own prokaryotic organisms, couldn't we take them out of a cell and place them in a safe, stable, nutrient-rich petri dish and watch them multiply?"
] | [
false
] | I'm not sure -how- someone would transplant mitochondria and chloroplasts in such a way, but I'm interested in how it would be done in practice and in theory and what the results would be. | [
"No. They are completely dependent on the host cell for survival. As evolution went on, a lot of their essential genes were moved to the host's genome.",
"Edit: It's actually quite interesting because even genes that are localized to their inner membrane are produced by the host and then transported across the o... | [
"All of the other posts are too vague. There is an exact mechanism known. ",
"Over time, many of their genes have migrated to the nuclear genome. The nuclear genome integrated them sporadically and the mitochondrial copy was lost due to loosened selective pressure. The reason for this, other than \"centralized co... | [
"That fact, and your explanation, completely blew my mind."
] |
[
"What is the mechanism that makes globally warmer temperatures mess with the weather like it has been?"
] | [
false
] | Melting the polar ice caps and causing flooding I get, but people have said that all this wild weather that's been happening recently is also a result of global warming. What's the mechanisms by which warmer temperatures can cause things other than just floods? Also, is there any truth to the connection people are mak... | [
"Climate scientists have been saying for decades that global warming would lead to wild weather. Now that it's here, they are careful to point out that there was harsh weather from time to time in the past, so it's not possible to say whether or not one wild storm or another is a direct consequence of global warmin... | [
"Indeed. It seems like if temperatures were evened out somewhat like is predicted, there would be fewer big weather events."
] | [
"Thanks for that. I really should have considered evaporation as well as just melting. "
] |
[
"When it's said 99.9% of human DNA is the same in all humans, is this referring to only coding DNA or both coding and non-coding DNA combined?"
] | [
false
] | null | [
"Both coding and non-coding DNA. Actually, 0.1% is a little bit outdated. The variance can be higher according to the 1000 genome project. It is said in ",
"this article",
" that",
"We find that a typical genome differs from the reference human genome at 4.1 million to 5.0 million sites. Although >99.9% of va... | [
"I think a thing people maybe don't realise is that the 99.9% figure was a bit of a guesstimate 20 years ago. It has taken something like the 1000 genomes project to actually calculate the number/amount of differences"
] | [
"Also, a concrete answer to the question doesn't really exist since the number of differences vary depending on how you count them. ",
"Some stretches of DNA do multiple, overlapping things, so is that counted as one difference or four? Some stretches of DNA can be the same in two people, but epigenetically expre... |
[
"Why don't they make serial hybrid cars with turbine engines, rotary engines or even with sterling engines."
] | [
false
] | Turbines (and I think rotary engines too) will create more power given size. That would mean that hybrid would have smaller combustion engine which would allow for a larger electric motor to give you speed and power in driving. Sterling engine are big and bulky for their power output but they are more efficient in prod... | [
"Turbines- Exhaust becomes a problem for turbines. The amount of heat that is exhaust from a turbine is enough to melt the plastic bumpers on cars that are behind and to the sides of a turbine dump.",
"There have been cars with a turbine engine before. ",
"http://www.allpar.com/mopar/turbine.html",
"Rotary- E... | [
"Well most of those issues would not be important in serial hybrid because the only thing turbine engine would do is power the battery that powers electric motor that drives the car. You could isolate the engine, put it anywhere in the car and always operate it at optimum RPM all the time.",
"The heat issue would... | [
"Turbines- Exhaust becomes a problem for turbines. The amount of heat that is exhaust from a turbine is enough to melt the plastic bumpers on cars that are behind and to the sides of a turbine dump. ",
"Rotary- Extremely inefficient. It's why there are only a handful of cars in vehicle history that use wenkel t... |
[
"What material changes its color when under mechanical stress?"
] | [
false
] | I remember from my mechanics of materials class a device which the professor used to help us visualize stress. It was normally translucent, but when he clamped down on it, colors appeared and showed stress lines. What type of material is this, and what phenomenon were we observing? | [
"You will need:\n- a working LCD monitor\n- Polarized glasses (many sunglasses are polarized, also modern glasses for watching 3D)\n- transparent plastic (I find CD cases to be perfect for demoing this)",
"Step 1: turn on the LCD monitor (duh) \nStep 2: display something white (Reddit.com is good enough)\nStep 3:... | [
"This is awesome! I took some video so everyone else can see what this looks like:",
"http://www.youtube.com/watch?v=-6U4uembaNQ",
"I shot the video through a pair of RealD 3D glasses.",
"Edit: Also the patterns change if I really bend and flex the plastic, but I couldn't do that effectively with one hand whi... | [
"No, there's a filter inside the LCD display, such that the light coming out of it is polarized. If you hold the polarized glasses in front of the monitor, and then rotate the glasses, you'll see the display looks much darker with the glasses rotated 90 degrees."
] |
[
"Is cancer transferable?"
] | [
false
] | null | [
"You're sort of right, but for the entirely wrong reasons. You're leaving out the fact that almost always, cancer researchers are implanting those tumors in nude mice, i.e., mice that lack an immune system.",
"A small number of cells could not start a tumor. If you transplanted an entire tumor (or, more likely, a... | [
"Those are exceptions rather than the rule really. We need to supress the immune system to transplant organs regularly and cancers would face the same problems."
] | [
"Cancers grow unregulated because they are mutated versions of the bodies own cells and avoid the immune system. In a different person they would be treated as a foreign body. \n",
"http://www.cancer.org/cancer/cancerbasics/is-cancer-contagious?_ga=1.240745857.309115939.1445569027"
] |
[
"Why does my voice sound like a robot when I talk into a fan?"
] | [
false
] | null | [
"fuck off muhammad"
] | [
"LOL go back to looking after the cats moomy"
] | [
"Also: you should try ",
"/r/explainlikeimfive",
" "
] |
[
"What is the shape of the universe?"
] | [
false
] | [deleted] | [
"When you look at those shapes the universe is the surface. There is no centre to the surface of a sphere. The reason you are thinking of the centre of the ball as the centre of the object is an artifact of the fact they have \"",
"embedded",
"\" the sphere into a higher dimensional space (and then drawn a 2D p... | [
"The saddle (the surface in the middle) has a distinguished point: the saddle point. But I explained in my other post that this does not mean space has a distinguished point. That's because the article only shows 2D-surfaces because we cannot draw a 3D region with negative curvature.",
"The plane is flat and infi... | [
"Only the hyperbolic paraboloid (the middle surface) has a distinguished point, also called the saddle point. The sphere and plane do not. Remember though that these are just 2D-surfaces with positive, negative, and zero curvature. They are presented in the article only has pedagogical tools since we cannot easily ... |
[
"Why does a battery appear dead when an electronic device cuts off from lack of power, but seem to regain charge after the device is cut back on?"
] | [
false
] | Say I'm using a cell phone. It will show one bar of battery left, then "die". The phone cut off because apparently the battery had no charge left. I then cut the phone back on and the battery is displayed with significantly more charge on it and the phone will continue to work for a while. Why/how does this happen? Edi... | [
"I'm a bit confused by your use of the verb 'cut' here... apparently it has opposite meanings here."
] | [
"Not directly related, but I am a computer tech and have a bit of experience in this field as it relates to laptop batteries. I can shed a bit of light on this.",
"Lithium-ion batteries you find in modern electronics operate a little differently than chemical-rechargeable batteries of the past (nickel-cadmium, f... | [
"Ah ok... well, I work in the TV engineering/production industry and when I see the word 'cut' it means 'loss of signal' or 'stop'. Two different worlds I guess.",
"I think my only guess to your solution is that certain devices only measure the 'good' voltage from their power sources... which means that when you ... |
[
"How in the world does Beethoven make plants grow faster?"
] | [
false
] | Or have I fallen victim to a myth? | [
"Curious to see a citation on the subject..."
] | [
"The evidence points to sound in general, not particular music"
] | [
"Plant growth signaling is really fascinating. And I totally don't understand any of it."
] |
[
"How are our voices and laughs \"shaped\"? Would you be able to change it completely with training, plus does one always have a \"signature\" voice?"
] | [
false
] | null | [
"So the way our voices are \"shaped\" is an interaction between the frequency produced my your vocal chords (ie pitch) and the shape of your vocal tract (ie throat, nose, mouth, tongue position). There is a theory that explains this relationship called the Source-Filter Theory. For individuals who whish to change t... | [
"In addition to gender identity, someone might \"change\" their voice for medical reasons. ",
"A classic example is Parkinson's Disease. Patients with hypokinetic dysarthria (a type of muscle \"weakness\" characteristic of the disorder) often develop a mono-pitch, mono-loudness vocal quality. This can greatly a... | [
"Could you give examples of training to change your voice please? Thanks"
] |
[
"Can Mosquitoes Carry Rabies?"
] | [
false
] | I know Mosquito's carry malaria, I was wondering about other diseases such as Rabies? Say a mosquito bit someone or something with rabies, and immediately bit someone else. Then this brings up the question of Ticks... Thanks! | [
"Nope. Cases of rabies are almost always attributable to the bite of a rabid animal. Old cases from a twenty year period between 1927 and 1946 showed that 99.8% of rabies cases came from bites from a rabid animal. Rabies is caused by a rhabdovirus that is transmitted only through saliva. Rare non-bite exposures inc... | [
"No. ",
"The Milwaukee Protocol has been discontinued.",
" Only one person was saved using the protocol despite over 25 attempts. Sorry, but wikipedia failed on that one. ",
"Source",
" "
] | [
"My friends wife who is a nurse was telling me about the survival rate, that is what prompted this question after a night of restless sleep!",
"\nThanks"
] |
[
"A fellow in this article says that some cell phone technology came from black hole research. Does anyone know what, specifically, he is referring to?"
] | [
false
] | null | [
"The only thing I can think of along those lines - in fact, the only \"practical\" effect of GR that I know of - is that GPS satellites use relativistic corrections to account for the very minute time dilation between clocks on the Earth's surface and clocks in orbit around the Earth. GPS essentially uses the time ... | [
"Possible although it would probably also be a stretch, I don't know of any telescopes designed primarily to observe black holes. But there are things which you could manage to fit into that box if you ",
" wanted to talk about black holes in a newspaper article."
] | [
"Another possibility is that a small component was invented for a telescope that is primarily used to study black holes, and has somehow found its way into mobile phones."
] |
[
"Why do bubbles cling to the side of the liquid's container?"
] | [
false
] | null | [
"I would guess that whatever is holding the bubble together is what helps is stick to a surface. A bubble is just a thin (thin being relative) layer of molecules that are attracted to each other enough to hold air inside of themselves. Bubble take the form of a sphere because it is the most even distribution of for... | [
"Despite how it appears to the naked eye and to the touch, even glass is a very rough surface on the molecular level. Rough enough for the bubbles to not just stick, but actually a be a place for carbonation to gather to form bubbles. "
] | [
"Nucleation Sites",
"Basically, small inperfections in the glass make it easier for the gas to condense out of the liquid at that point.",
"Mentos are apparently like one big nucleation site (their surface is very rough at microscopic levels?), so they cause masses of bubbles to form all over their surface."
] |
[
"Why do shellfish turn orange when cooked?"
] | [
false
] | null | [
"The pigment that colors crustaceans is held by a protein. Heating the crab/lobster denatures the protein (similar to the manner that cooking an egg changes the transparent white into .. well, white). Once the protein is denatured the pigment is released and changes the color of the shell.",
"This is also the rea... | [
"I've answered the same question before",
", here's the C&P:",
"The responsible protein is called Crustacyanin. It is a multi-protein complex that consists of several variants of crustacyanin. But in addition to these protein components, the complex also contains astaxanthin, which is a ",
"carotinoid",
". ... | [
"Here is an answer I gave a while back",
".",
"In the future you can do a quick search for past threads."
] |
[
"How does the human body turn sunlight (no mass) into vitamin D (mass)?"
] | [
false
] | null | [
"Ultraviolet light penetrates the skin and strikes a compound in our blood called 7-Dehydrocholesterol. This converts it to another compound which eventually becomes vitamin D3. The sunlight itself isn't turning into vitamin D, it allows our body to produce it, since it contains the right kind of UV light to stimul... | [
"You don't just turn sunlight into vitamin D. There are chemicals in our bodies which combine to form vitamin D, but need a kick of energy in the form of sunlight to allow them to come together to actually form vitamin D."
] | [
"This right here is why the farther you get from teh equator, the lighter skin the natives have. You need to absorb the rays for vitamin B production when you live in the arctic, and you need to block the rays to stop sun burn and skin cancer when you live near the equator.",
"It's also (part of) why judging som... |
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