title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why do different bodily crevices produce different odours?"
] | [
false
] | null | [
"Different bacteria which produce different odors prefer different spots on your body."
] | [
"Can you expand on this? How do bacteria know which area of the body they're on? How do different bacteria migrate to specific body parts?"
] | [
"There are thousands of strains of bacteria on your body that colonize you from the moment you are born, and grow up. By the time you hit puberty and start to sweat a lot more, the bacteria that prefer those places and sweat excretions proliferate. "
] |
[
"Has jewelry always been popular? If so, why?"
] | [
false
] | [deleted] | [
"Jewllery was worn around 50 to 100,000 years ago.",
"*The earliest known pieces of jewellery made by modern humans have been identified by scientists.",
"The three shell beads are between 90,000 and 100,000 years old, according to an international research team.*",
"http://news.bbc.co.uk/2/hi/5099104.stm"
] | [
"In a lot of cultures, especially those without banking structures, a piece of jewelry might be worn as an heirloom with the expectation that it can be cashed in at a dire time, like during a failed harvest or to support medical treatment for a family member. "
] | [
"In the category of \"love of shiny things\" humans are bested only by raccoons."
] |
[
"[chemistry]When a hot beverage releases steam does the concentration of let's say coffee increase?"
] | [
false
] | null | [
"It depends on the temperature and the compounds of the beverage. If the temperature is just enough to make the liquid (e.g. water) evaporate, yes, it is going to increase the concentration of the other compounds because the volume of the solvent (water) is decreasing and the amount of the compound (e.g. salt) stay... | [
"As another example: with alcoholic drinks, the alcohol concentration will go down."
] | [
"Not always. Vapor content will depend on what's in the mixture and at what ratio. Look up azeotrope. "
] |
[
"How long would it take for all traces of civilization to vanish?"
] | [
false
] | Basically I'd like to know how long it would take to make the earth seem like there never was human life on it. Say, to make this easier, your best tool to determine that would be a single probe like the mars rover to collect data for a limited amount of time. And visuals by satellite or telescopes or whatever. | [
"Your question is answered in great detail in the Discovery Channel show ",
"Life After People",
", and in the book ",
"The World Without Us",
".",
"The short answer is that some human constructions (like the channel tunnel for instance) will survive for billions of years."
] | [
"they tend to miss a lot."
] | [
"Jewelry. A clear sign of intelligent life acting upon natural resources for cultural and economical reasons, they would never vanish or decay, no matter how much time passes."
] |
[
"Do tetrachromats see a fourth primary colour completely independent of the other three?"
] | [
false
] | On occasion, I've tried extremely hard to imagine a colour outside of the primary colours - red,green,blue and obviously their composites (yellow, cyan and magenta), without success whatsoever. Do tetrachromats see a completely new colour with their fourth cone, or is the perception merely a mix of the previous red/gre... | [
"Funny you should mention cyan, since I created an optical illusion to show true cyan a while back entitled \"Eclipse of Mars\": ",
"http://www.skytopia.com/project/illusion/2illusion.html"
] | [
"I believe this is so. Tetrachromats can distinguish a pure orange color from a mixture of red and green. It is similar to how most people can see entirely different colors from dichromats. Keep in mind, though, that \"colors\" don't really exist as such - - the visual processing part of our brain assigns colors to... | [
"I think this ",
"Radiolab",
" episode will help clarify tetrachromacy."
] |
[
"Does exercising a tongue make it bigger like other muscles?"
] | [
false
] | "Regular" (for lack of a better term) muscles will get bigger and stronger when put through exercise like going to the gym but I was wondering, if you could for example lift weights with your tongue, would your tongue get bigger? Would it make any sort of change it? | [
"Yes. In the treatment of a swallowing disorder (aka dysphagia) we often target tongue strength. There are a variety of exercises we use to do so. Some of them include a form of resistance, but none use “weights” per se.",
"Typically, when a regimen of these exercises is followed, tongue strength improves (the to... | [
"Thanks a lot for answer! Very informative"
] | [
"I do very much appreciate the answer even if I am having some trouble understanding it. I actually do have a background in science, it just really doesn't help me right now because it's computer science (looool).",
"I think I get gist of it though... Maybe. Exercising the tongue will help strengthen and physical... |
[
"Why does the sound from rocket launches tend to change suddenly at a certain altitude?"
] | [
false
] | After watching numerous videos of rocket launches, from huge launches like the Space Shuttle or Saturn V, to big rockets like the Delta IV or Titan IV, to smaller rockets like the Atlas V, I've noticed something about the sound of the launch that is the same in almost single video. At first the sound begins as a deep r... | [
"What an interesting question. As near as I can tell, it's related to the behavior of the tail of the rocket exhaust. At the risk of not being able to cite anything definitive (I can't find any studies covering the audio characteristics of rocket exhaust), and having to go on hypothesis, although an educated one ba... | [
"the crackling sound begins well before the vehicle reaches the speed of sound.",
"I support this because the multiple shockwave effect of the ",
"transonic regime",
" is clearly visible in some of the videos long after the crackling noise starts."
] | [
"I'm not sure about that. In all of the examples I posted (as well as all of the other videos I've seen) the crackling sound begins well before the vehicle reaches the speed of sound. For example in the Apollo 11 video, the crackling sound arrives around 35 seconds after launch, but the rocket doesn't go supersonic... |
[
"Since beta particles are electrons, can they be directly converted to electrical energy?"
] | [
false
] | Please correct me if I'm wrong, but if you had a beta emitter and a piece of lead next to each other, the emitter would emit negatively-charged beta particles and become positively charged, while the lead would absorb the beta particles and become negatively charged. If this occurs, is it practical as a power source? | [
"Yes, this is done through a ",
"betavoltaic cell",
". These used to be use to power pacemakers. Nuclear decay is also used to power space probes, except it's through excess heat rather than direct betaelectricity."
] | [
"Radiation is not magically worse than anything else that goes into your body, it is just a matter of the dose. In the case of pacemakers the amount of radiation is so small, that the risk of this technology is outweighed by the risk associated with surgery to replace a battery that is depleted or faulty. ",
"Rad... | [
"A proper Betavoltaic battery both doesn't contain a huge amount of radiation, and is in a hermetically sealed case. Beta radiation isn't really penetrating and if you managed to break a hermetically sealed metal can inside your body, I think you may have larger issues than it leaking. "
] |
[
"Why does nature sometimes prefer right or left? Example: Lorentz force"
] | [
false
] | Hello everyone, I'm a Electrical Engineer on a university and know how to use maxwell equations in calculating many things like inductance and capacitance between objects. I also know that somethimes nature prefers to choose for a certain direction like magnetic fields around a wire with flowing current or the lorentz ... | [
"I see where you are coming from here:",
"If you have a vertical wire, with a current going up, then the magnetic field wraps around the wire according to a right-hand rule - counterclockwise when viewed from above. If I look at this wire in a mirror, the magnetic field is going in the other direction - clockwise... | [
"zeug gave a nice answer, but since you're a student I'll post an even deeper answer too. The right-hand rule and similar things come from a cheap hack that you're taught throughout school. You've been learning about vectors and cross products and \"charge-motion x field = force\" and things like that. The Loren... | [
"Thanks for this answer. It was very usefull. So the cross product used in the maxwell equation are just to make physics easier just like torque makes mechanics easier?"
] |
[
"The star cycle, as I understand it, goes from a young, bluish star, through to a white, then yellow, then orange star, then a red giant. Why doesn't it become green?"
] | [
false
] | null | [
"Because the 'color' has to do with predominance, they're not a solid color like a crayon. Green's right in the middle of the light spectrum, so it's at the 'peak' of a bell curve of colors, with an equal amount of spectrum on each side, ",
"so it looks more 'white'",
" than green. As you get further to the ... | [
"A star's radiation (light) comes from ",
"black-body radiation",
" from its photosphere. If you look at the Wikipedia article linked, you'll see some example graphs of how temperature affects the light emitted. Basically, as the temperature increases, the intensity of the light emitted increases very rapidly a... | [
"There are stars which have their peak emission in the green part of the spectrum (the Sun is actually one), but, mostly because of how the human eye works, they all appear white. See ",
"this",
" article."
] |
[
"Can someone please explain Gravitational Lensing?"
] | [
false
] | As in; how does it function, and how can we use it? | [
"A lens operates by refracting light. Like focusing ",
"incident beams",
" or diverging them. The point is, the direction that the light travels has changed.",
"Now imagine a lump of mass in space, it distorts spacetime itself, such that what a \"straight line\" is, is fundamentally different and altered. Thi... | [
"Hi ",
"/u/MrGreene1",
",",
"How does it function?",
"To explain how gravitational lensing ",
", let me begin with some fundamental features of the general theory of relativity. In the general theory of relativity, spacetime and the energy density of the universe influence one another according to ",
"E... | [
"This image",
" shows how the beams (that normally would travel straight) appear bent when they pass a massive galaxy cluster.",
"The amazing thing with the last image AsAChemicalEngineer showed is that the blue ring around the yellow massive object is actually the \"refracted\" image of a single, small galaxy ... |
[
"Are there Materials with good thermal conductivity but electrically isolating?"
] | [
false
] | I'm looking for Materials which are electrically isolators and good thermal conductors like diamonds. Preferably easier to mashine and cheaper than diamonds. | [
"Widely used is ",
"beryllium oxide",
". Looks like porcelain, feels cold like copper.",
"In your high-power radio transmitter, if the vacuum tubes have some white sections rather than glass, that's BeO. Same with CO2 laser tubes, microwave oven magnetron tubes, and parts of older high-volt connectors. So... | [
"Diamond"
] | [
"Ceramics are one. Here are some examples from googling:",
"http://www.ceramtec.com/ceramcool/",
"http://www.heatmanagement.com/en/produkte/thermally-conductive-ceramics,38",
"http://www.surmet.com/technology/aln/index.php"
] |
[
"How likely is it that there are undiscovered fossils on the ocean floor?"
] | [
false
] | I was watching a show about the mesosaurus and it got me thinking: is there an estimation of the number of ancient/extinct species that have yet to be discovered because their only fossils could be found on the ocean floor? For example, is it possible that there was a large species of shark that has not been discovered... | [
"Fossils? ",
"Sure.",
" And plenty, plenty more. You are about to make a voyage of discovery if you're up for it. Check out the ",
"Census of Marine Life",
".",
"Some highlights from their 2010 press release",
":",
"250,000 extant marine species have been described, but it is estimated that at ",
... | [
"To clarify from a geologists perspective...",
"We do have exposed ancient sea floor rocks - when continents collide they get pushed up and eventually exposed by erosion. In fact, ",
" sedimentary rocks are marine in origin (mostly shallow though), as most other depositional environments don't hang around long... | [
"More detail ",
"here",
". This is actually worth the read if you have any interest in marine biology. Also, pretty pictures.",
"Most detail ",
"here",
". This is for the true wonks. Beware, serious science lies beyond this link."
] |
[
"I found 3 baby birds out of their nest, what do I do?"
] | [
false
] | null | [
"http://www.nwrawildlife.org/sites/default/files/FoundBird.pdf"
] | [
"It means, \"the bird needs help but it's against federal law for you to help it yourself, plus you'll inevitably feed try to feed it something like birdseed or bread, which will make it die of malnutrition, since baby birds need very high protein diets that you don't know how to make; and you also won't know how t... | [
"It means, \"the bird needs help but it's against federal law for you to help it yourself, plus you'll inevitably feed try to feed it something like birdseed or bread, which will make it die of malnutrition, since baby birds need very high protein diets that you don't know how to make; and you also won't know how t... |
[
"Is there any clear science indicating why some people procrastinate more than others?"
] | [
false
] | And, bonus question, why some people are punctual and others aren't? Are the two questions related, as it seems they should be at first blush? | [
"Unfortunately questions of why the differences are going to be difficult for any of us to answer. Individual differences can be seen as a combination of the following: Genes, Current Biology, Learning History, current perceived context.",
"At this point in psychology we accept that there is a 1:1 relationship b... | [
"My understanding of procrastinating behavior is that it is a reaction to balance the lack of inherent motivation a person has for some task against the fear of the consequences for not finishing the task in a bid to increase productivity. The closer the deadline for something, the greater the likelihood of the con... | [
"I would be fascinated to hear a behavioral analysis of procrastination."
] |
[
"Question About Volcanoes."
] | [
false
] | I understand the concept behind volcano formation, and how they create islands, but what I don't understand is why islands aren't one long strip of land. What makes it so the hot spot doesn't continually add on to one island and makes it instead many small islands like in Hawai'i? | [
"The two things I can think of. ",
"Hot spots tend to wax and wane in their overall intensity and power over time, Sometimes they have enough energy to push through the crust and at other times they do not. ",
"Related to this is the notion that the crust is not always uniform in it's density and composition, s... | [
"For the same reasons that volcanoes don't (generally) continuously erupt. The magma underlying the hot spot gets more active and less active in cycles over long periods of time.",
"The Kilauea caldera is currently quite active for example, but has gone through periods of greater or lesser activity over the last ... | [
"Vinegar and baking soda, that's why."
] |
[
"Should some research just not be carried out? Or, if you are going to threaten most people on the planet, how can you possibly secure it?"
] | [
false
] | I'm thinking in particular of , which I read this morning. My concern isn't just about the idea he might put out the recipe, or that some terrorist might want to make it. It's the concept of having made something in a lab that could be responsible for billions of deaths. Put another way, I do risk assessments for a liv... | [
"I don't think he is describing stopping research because of petty morals and fears, but rather stopping research because of sensible, near universal values and well grounded fears. ",
"And I would say its moot. There is not stopping it now even if it does spell our inevitable doom."
] | [
"An an aspiring engineer, and a man of science in general, I will say NO. Absolutely not.",
"Research in itself is ",
" a bad thing. It's only bad when the wrong people get the wrong ideas and do something terrible. This should not govern how we develop. ",
"The moment we stop pushing the boundaries of scienc... | [
"There is no reassurance unfortunately.",
"That said, this article is alarmist as hell. Its highly contagious, but it is still the flu. The worst thing that could happen is a 1918-like pandemic, and the best thing that could happen is the the prevention of many future pandemics, which seem to happen every 30-40 y... |
[
"If you leave something in the freezer for 3 years vs. 1 day, will they thaw at the same rate?"
] | [
false
] | [deleted] | [
"If the food item is frozen completely after a day, and that there is no chemical or physical change from storing the item for 3 years, then they will thaw at the same rate."
] | [
"When first frozen the ice crystals will be relatively small. Over time the size of some ice crystals will increase at the expense of other smaller crystals (a process known as Ostwald ripening). The larger crystals will melt slower than smaller crystals.",
"Yes, the longer-frozen food will take longer to thaw ... | [
"You're correct - I've neglected to consider the kinetics from crystal sizes. I should know better too, seeing how I've dealt with nanoparticles before and Ostwald ripening is responsible for the bimodal size distribution."
] |
[
"If a medieval knight in full plate mail got struck with lightning, would he escape unscathed?"
] | [
false
] | null | [
"The resistance of the mail would be orders of magnitude lower than that of the knight, so it is unlikely that electrocution would occur as the majority of the current would be external. However, metal objects worn on the skin during lightning strikes ",
"may result in burns",
".",
"A sharp discharge (rather ... | [
"Lets work out a back-of-the-envelope calculation. It won't be entirely accurate, but should give some idea.",
"OSHA has numbers for the resistance: ",
"http://www.osha.gov/SLTC/etools/construction/electrical_incidents/eleccurrent.html",
"Thunderstorm, so we'll assume wet -- 1000 Ohms for the human.",
"9.5... | [
"If only his clothes under the armor touch the metal, the armor might act as a Faraday cage.",
"\nBut totally unrelated, I just figured out how people came to think magic existed.",
"\nWar while Thunderstorm. Oh god, they have a mage!"
] |
[
"How is it that all of the human genome is only 800 megabytes in size?"
] | [
false
] | It's mind boggling that it takes up so little room. How is all that information stored in only 800 megs? | [
"800mb is a LOT of data! That's nearly 5000x 100 page books.",
"20 years ago, 800mb would have been considered a ",
" amount of data. I think your opinion is skewed by modern storage requirements.",
"Also, nature has had 3.5 ",
" years to build the most efficient mechanisms it can. Mankind has barely had 75... | [
"You need to clarify your question: are you asking how much information the human genome sequence can encode, or how big a computer file containing the human genome sequence would be? Related previous question:",
"https://www.reddit.com/r/askscience/comments/3qsel7/how_much_data_contains_the_human_genome/",
"T... | [
"Sorry, I was more asking how the blueprints for humanity and life can fit into such a small area. It seems ridiculous compared with how much data computers need to do relatively simple tasks."
] |
[
"How does gravity obey the law of entropy? Matter coming together seems to increase order."
] | [
false
] | [deleted] | [
" This is a ",
" statement, and while it is sometimes accurate, it is a poor general rule.",
"Entropy is energy not available for work, ie: HEAT."
] | [
"I'm not following how you're using \"isotropic\" there.. But the simple answer is that ",
"tides do change the energy of the earth and moon",
"."
] | [
"Close. Two objects who are brought together by gravity lose gravitational potential energy. It becomes kinetic energy or other forms of energy, which gives you an increase in entropy. ",
"To take a straightforward example, two asteroids get pulled into each other, accelerating towards each other until they colli... |
[
"Considering an electron has angular momentum but without the movement associated with it, wouldn't that (possibly/likely) reflect the electron having particles within it (as a proton has three quarks)?"
] | [
false
] | null | [
"If the electron had an internal structure like you suggest, it would have an electric dipole moment, but experimental searches for such a dipole moment are extremely restricting. It has to be below 10",
" meters (times its charge). That's not to say it can't or doesn't exist, but it's not part of conventional ph... | [
"Given the upper bound for an electron radius of 10",
" m and the mass of an electron, it would have to be moving at nine orders of magnitude faster than light. If it has an internal structure, that's not where the angular momentum comes from."
] | [
"Here's a justification for why a particle like an electron ",
" have spin. This got a bit more long-winded than I intended when I started writing, so hold on tight:",
"In your typical, non-relativistic quantum mechanics, the behavior of a particle is described by a ",
"wave function",
", and the behavior o... |
[
"If corn was originally a multi-colored plant, why/how (after years of selective breeding) did we eventually arrive at the common color of yellow?"
] | [
false
] | I am interested in the evolution of color in this case. Why yellow and not one of other original colors? Perhaps my question is just incorrect on the outset. | [
"The ",
"evolution of corn",
" is an interesting topic, but there is a lot of corn that is not yellow. The typical United States crop corn is '",
"field corn",
"' and it is a specific strain that was bred to be hardy and pest-resistant. Since most farmers use this same type of corn for animal feed and food ... | [
"First I would like to show the diversity of corn/maize (",
" varieties) that we have nowadays, most of this varieties were domesticated in México. Image ",
"here",
".",
"Now, I would like to tell what is responsible for the colours of corn. Inside the DNA, there are little sequences of DNA that are capable... | [
"='D this is the first time someone replies to my answer with a \"thank you\"!"
] |
[
"pH question. I read that the concentration of H ions multiplied by concentration of OH ions always equals 1 x 10^-14. How does this work?"
] | [
false
] | Intuitively I understand when two quantities ADD up to a constant, but I can't grasp what would cause two quantities to MULTIPLY to constant. What's happening here? EDIT: Thanks everyone! | [
"The two quantities multiply to a constant because the system is in equilibrium. An ",
"equilibrium constant",
" describes the ratio of reactants and products of a reaction at equilibrium. The equilibrium constant does ",
" describe the total amount of reactants or products in a system, which is probably what... | [
"I can rationalize it (to myself, anyway) as: The number is the ",
" of one water giving it's proton to another. By the rules of probability, the likelihood of 2 things happening are the product of the individual probabilities. The two probabilities in this case are the likelihood of one water giving up its pro... | [
"pH, by definition, is the negative logarithm of the concentration of protons* in a solution. ",
"A water molecule gains a proton by becoming a hydronium ion:",
"H2O + H",
" ==> H3O",
"/* actually, the negative logarithm of hydronium ion concentration. "
] |
[
"Why does plastic bottles (especially from water companies) have curves ?"
] | [
false
] | Hello everyone .. I've always ask this question and searched about it but unfortunately I didn't find the answer yet. Why does plastic bottles (especially from water companies) made in curves ? And each company has its own design of curves ? Is it something related to economic returns (to use less of their product) ? e... | [
"The grooves in the bottle help increase the rigidity of the bottle, and also help set the appearance of the bottle apart from their competitors bottles.",
"As far as quantity is concerned, you can easily measure the contents of the bottle, and you will find that the bottle contains almost exactly as much of thei... | [
"Larger annular grooves are primarily incorporated into the design of the bottle to make the bottle easier to grip."
] | [
"That makes a lot of sense, especially with sports-drink bottles. Your hands being sweaty and the condensation on the bottle would go a long way for an accidental spill. "
] |
[
"Solar sails and how they work?"
] | [
false
] | EDIT : All who repleyd THANKS i have now the awnser i looked for thanks to you. The problem with myself was that i thought to basic on the mass gives push and didnt consider that momentum is also a factor that could deliver the needed force When people talk about light there is spoken of a massless thing. ( as far i... | [
"The momentum of light is as physical as anything else. It's just not how we're used to things working.",
"Interestingly, ",
"a mirrored box of photons has mass",
" while a free photon does not. Mass really is bound energy."
] | [
"Light has no mass but it does have momentum. P=mv is an approximation that doesn't apply to all objects, for example light. It's momentum is associated with its energy. A higher energy (more blue) light has more momentum than lower energy (more red) light"
] | [
"One way to get a feel for why light can carry momentum is to consider what a light wave is; it's oscillating electric and magnetic fields. Now, remember what the definition of an electric field is; if you put a charged particle in the field, it will experience a force. ",
"Force is rate of change of momentum, so... |
[
"When will earth lose the moon?"
] | [
false
] | The moon is moving away from the earth at a rate of 4 cm per year. How long before it escapes our orbit? What will happen to it then? | [
"We will not lose the Moon. It will recede as it exchanges energy with the Earth by slowing our rotation. Eventually the recession will stop when the Earth becomes tidally locked to the Moon and one side of the Earth will always face the Moon. ",
"The opposite process has already happened and the same side of th... | [
"That's eventually the same, isn't it? If there is more mass, then there is more stuff to have angular momentum in the first place. Though, if we had two earth-mass planets with a 12 hour and a 36 hour day, the process would take longer and shorter respectively. "
] | [
"While this is true, there are other possibilities for the moon to escape the earth gravity. As the Solar system is composed of more than 3 bodies, it is chaotic, and for very long time scales many strange things could happen, as Mars-Earth collisions, and the like.",
"See for example :\n",
"https://en.wikipedi... |
[
"What tectonic plate is this map showing in the Southern Atlantic?"
] | [
false
] | Hey, I'm just a student who cares a lot about geology and cartography, and over the past several weeks I've been researching and mapping out several aspects of Earth's tectonics. On a page called "iflscience" I found the map in the Imgur link below. I had been looking into unconfirmed plates all around the globe, and w... | [
"Since this comes from a research article on micro-plates, it's likely that the authors are micro-plate enthusiasts who're more likely to be aware of (and more likely to accept) evidence of smaller plate motions. For instance, the map also shows the ",
"Capricorn Plate",
", which doesn't show up in most standa... | [
"It's a pity because when IFLS started it was run by just one person who has a background in science (B.Sc) and it had lots of really interesting and well written content (including references)... but now it's mostly just click bait.",
"Btw, regarding Wikipedia, it can be a great place to start so long as you che... | [
"Thank you, I hadn’t found any evidence with the resources I had... Which is basically Wikipedia, and google, so thank you.",
"I’ll make sure to use IFLScience with caution."
] |
[
"Stellarium says that on 18th January, 0th year, the Sun rose at 1:00 AM as per current convention. Why is this?"
] | [
false
] | Here is a : date -> 18th Jan , 0 A.D time -> 1:51 AM location -> Earth, Bangalore {12° 58' N, 77° 38' E} Why does the date-time convention go haywire? turns out it is a bug. I downloaded the latest version (0.11.1) and the bug seems to have been fixed in this. Thanks guys. | [
"There is no year 0 in ",
" terminology, but contrary to the parent's impression this is not ",
"/r/history",
". Astronomers use different conventions.",
"The year before 1 is 0, so e.g. the historical year 100 BCE = -99. Also note that dates in that era conventionally follow the Julian calendar, not the Gr... | [
"I checked for multiple date values in Stellarium again and found this:",
"On 18th Jan, 500, Sunrise is around 1:30 AM IST {GMT+5:30}",
"On 18th Jan, 750 A.D, Sunrise is around 1:30 AM IST {GMT+5:30}",
"On 18th Jan, 999 A.D, Sunrise is around 1:30 AM IST {GMT+5:30}",
"On 18th Jan, ",
" A.D, Sunrise is aro... | [
"As I suspected, the program Stellarium says that on the 19th January 2012, the sun rose around 1:00 AM as well.",
"This is just a confusion between UTC and IST (Indian Standard Time)."
] |
[
"What causes the patterns to appear in this maple syrup?"
] | [
false
] | I've tried searching for maple syrup ripples/waves/evaporation/pattern but haven't found anything explaining this. I'm guessing it has to do with some of the water from the syrup evaporating, but not sure why it seems to dance around like this. | [
"I can't be certain about this, but after doing some research I came across ",
"this",
" paper, which describes periodic ripple formation in other media.",
"What could be happening here is that a very thin skin is forming on the surface of the syrup. As the pool evaporates, the total volume of syrup is decrea... | [
"periodic ripple formation in other media",
"If you're interested in this, I've collected a variety of ",
"thin film patterns",
" on my site."
] | [
"The tubs I get the syrup from usually have a sort of \"skin\" at the top layer, but it probably stays like that because there's nothing to heat it up, I suppose."
] |
[
"What happens to air when it escapes into outer space?"
] | [
false
] | null | [
"You get isolated gas atoms/molecules that follow their own orbits until they collide with something. If you release gas in a low Earth orbit then essentially no particles reach escape velocity, so almost all the gas becomes part of Earth's atmosphere."
] | [
"There is no hard limit of where atmosphere ends and outer space starts. It just gets less dense the further one is away.",
"Molecules can just get yeeted into space, never to be seen again. Other molecules from other planets can come to ours, ours can go to others. They can be struck by solar wind, getting strip... | [
"Scientific definitions have to be precise and we must be ready to give up on our long cherised notions. Except for Pluto. I'm still Team Pluto. Those astronomers...what do they know. :-)"
] |
[
"what is the strongest metal known to man?"
] | [
false
] | i'm sorry if it seems like a stupid question but i've always wondered what the strongest metal known to man is | [
"The Strongest Natural Metal: Tungsten",
"As far as pure metals go, Tungsten has the highest tensile strength with an ultimate strength of 1510 Mega-Pascals. Tungsten also has the honor of having the highest melting point of any unalloyed metal, and second only to carbon on the whole periodic table. Tungsten is v... | [
"They are vastly superior to even the best steel alloys in most regards (uts, ym, ultimate temperature etc) but as you say tend to be extremely expensive. Coming from an aerospace course I can tell you a turbine blade the size of your hand costs well over 100,000 pounds."
] | [
"Da fuq?"
] |
[
"If you mounted a speaker setup at the front of a train that played, in all directions, a song extremely loudly..."
] | [
false
] | If you mounted a speaker setup, at the front of a train racing along at just over the speed of sound(on silent maglev tech), that played, in all directions, a 5 minute long song extremely loudly (loud enough to be heard dozens of miles away)... Would someone you passed 5 minutes later hear the song in reverse? | [
"If the train was going faster than the sound waves by that smidge though, wouldn't it be playing the next slice of sound closer to the audience than the last?"
] | [
"This webpage",
" appears to answer your question. Depending on where the observer is standing, the song could be \"heard\" in reverse. I suspect the waveform would sound completely different, though."
] | [
"It's moving just over the speed of sound in the question."
] |
[
"Why don't they inject little bits of RNA that are complimentary to HIV in someone with AIDS?"
] | [
false
] | If HIV is a retro virus then couldn't you insert little bits of RNA that by itself wouldn't code for anything but would bond to the HIV mRNA and shut it down? Even if the HIV virus mutated it would still need to have some parts of it that don't mutate so it still functions right? | [
"This has been done, and the process is called antisense RNA. Here's an ",
"article",
" that I've googled at random for demonstration. One potential problem is that double stranded RNA is sometimes interpreted as a viral infection and the cell has a toxic reaction to it. So instead of suppressing the virus you ... | [
"If you simply inject the RNA into the patient' bloodstream, it's going to be degraded almost instantly and won't do any good. You need a way to get the RNA into the cells where the HIV is. People are working on this! There are clinical trials and stuff.",
"Here's a review of some of this work",
".",
"Complem... | [
"For the benefit of the people who can't get through the jargon of the paper you link to, I'd like to point out that this is not injecting RNA into a subject, but rather treating cells in a dish with a modified virus that contains the complimentary RNA sequence. ",
"That worked, but as you say the real problem is... |
[
"Is the chemical composition of 1st dose and 2nd dose of the Covid-19 vaccines the same?"
] | [
false
] | I saw a vaccination center that was administering the vaccine only to people taking their second dose. So was wondering is it because the dose 1 and dose 2 are different and they have stock of only the second dose or they are prioritizing the dose 2 as there is timeline within which it needs to be taken. I am in partic... | [
"For the AstraZeneca, BioNTech/Pfizer, and Moderna vaccines first and second shot are identical. The only COVID-vaccine with different first and second shots that I am aware of is the Russian ",
"Sputnik V",
", which uses different Adenoviruses (types 26 and 5) as vectors in the two shots."
] | [
"It’s the same vaccine for each dose. ",
"As for why they’re prioritizing the second dose, I would speculate it’s due to a supply issue. The decision was likely made to ensure the remaining stock was used to fully vaccinate as many individuals as possible rather than give that supply as a first shot and then have... | [
"No, they are both the same as far as I am aware. We generally would not change the vaccine as the purpose of the second dose is to re-prime the immune system and train the immune system into creation of long-term antibodies, which only occurs with 2+ exposures."
] |
[
"Do *all* liquids always constantly evaporate?"
] | [
false
] | Liquid water temperature constantly evaporates as long as the air is not at equilibrium, and will stop once the air is humid and equilibrium has been reached. What about other liquids? Lets say I have a vat of molten iron, would the molten iron (which is now in a liquid state, melting point = 1811 K) also evaporate wit... | [
"Sure, there is always some vapor liquid equilibrium between a liquid and a gas. It might be incredibly tiny, such that parts per trillion or less levels of the liquid make it into the gas, but there is some amount that will escape the liquid phase even if that number is vanishingly tiny. For any temperature abov... | [
"I was wondering something similar some time ago: if all condensed matter vaporizes over time (and it does), why isn't there an intermediate step, a liquid film on all solids? Porter and Easterling briefly discuss this point in ",
". Briefly, the requirement to nucleate a liquid (in contrast to a gas) generally p... | [
"correct me if Im wrong... but dont solids also evaporate through sublimation? Not sure if thats true of all solids..."
] |
[
"Why is memory sometimes lost after trauma?"
] | [
false
] | Why is it that in most cases you hear of, it’s usually short term or long term memory that is affected or lost after experiencing some kind of head trauma? Why is remembering how to talk or involuntary function rarely affected? | [
"Commenting to look for those updates. Thanks for this answer by the way!"
] | [
"Commenting to look for those updates. Thanks for this answer by the way!"
] | [
"If you are asking about being unable to recall the events immediately prior to some type of trauma it is because those memories never get a chance to be consolidated into long term memory. Consolidating memories into a long term store can take several hours."
] |
[
"Does every sensing cell have a unique line of nerve cells leading to the brain?"
] | [
false
] | My thought pattern: in for example a hand there are a ton of different senses (pain reception, heat, pressure). These are (I believe) measured by certain cells, after which they send a signal to the brain. So say there are 1000 of these cells in my hand, are there also 1000 "cables" leading to my brain? Or is the signa... | [
"Let's start with some background on nerve endings:",
"All of these receptors (for pressure/vibration, temperature, and pain respectively) are derived from the ends of sensory nerves. Mechanoreceptors can be classified into ",
"Meissner's corpuscles",
", ",
"Merkel cells",
", ",
"Ruffini corpuscles",
... | [
"Nope. In vision, for example, it is frequently the case that there is a high level of convergence from photoreceptors to downstream cells, e.g., hundreds of rods may converge to one bipolar cell, so information is lost."
] | [
"Source? I'm pretty sure there's a high level of ",
"vergence in the visual system."
] |
[
"Are unprofitable but effective cancer drugs really being withheld from the public?"
] | [
false
] | I have been hearing more and more about drugs that effectively treat cancer but are not being supported by pharmaceutical companies because they can't make a profit on them. For example, I have heard of dichloroacetate (DCA) and hydrazine sulfate (HS) but since they are apparently common or cheap, study funding is hard... | [
"No, it's media hype and conspiracy theorists. ",
"DCA",
" and ",
"HS",
" (Read about halfway down for the info on HS",
"Edit: Closed parens for tHeSiD. "
] | [
"Also, the notoriety gained from being the first pharma company with \"THE CURE!\" would far outweigh the fairly negligible drop in revenue."
] | [
"The scientists involved in creating the drug would have to willingly hide a discovering that would make their career, win them a Nobel Prize and get their names in every history and medical textbook printed from that day on. You think a job at a drug company is worth that? No way."
] |
[
"How does saturation of multiple solutes work?"
] | [
false
] | null | [
"It depends on the chemical properties of the exact species that are in the mixture. Adding ions increases the ionic strength of the solution. Ionic strength factors into the activity coefficient of each solute; this coefficient \"corrects\" the concentration of a particular species for non-ideal effects (solute-so... | [
"It depends, and not just on the solubilities. There is a common ion effect which is at play if you have, for example, two solutes which have a shared counterion when dissolved. "
] | [
"I don't think you can make any definite statements like that, at least not to my knowledge. The problem - as I understand it - is that you're dealing with saturating amounts of each solute, which makes it a very non-ideal situation.",
"Your best bet is probably to trawl through the chemometrics work as it relat... |
[
"If I shoot a bullet straight up in the air and it returns to earth at my feet, at what point was the bullet at its highest velocity?"
] | [
false
] | null | [
"The highest velocity is when the bullet just leaves the gun. From then on the air friction and gravity slow it down. If the gun is above the ground you could argue it falls further that it ascended. However, one would have to take the terminal velocity into account. That would be a complicated calculation."
] | [
"Doesn't matter. The bullet (assuming it is a modern firearm) is gyroscopically stabilized by the spin imparted by the rifling in the barrel. If fired straight up the bullet will travel up until it loses all velocity and stalls. At this point it will no longer be stabilized by spinning and it will begin to tumbl... | [
"Doesn't matter. The bullet (assuming it is a modern firearm) is gyroscopically stabilized by the spin imparted by the rifling in the barrel. If fired straight up the bullet will travel up until it loses all velocity and stalls. At this point it will no longer be stabilized by spinning and it will begin to tumbl... |
[
"Do we have any historical/archaeological evidence of a 100% lethal virus that solely wiped out a species, any species?"
] | [
false
] | Just watched Contagion last night and got to thinking... | [
"I do not think so.",
"100% lethal viruses to a whole species do not occur in nature. ",
"Oddly enough this is something explored in bio-weapon design. A virus that is highly contagious, has a long incubation time (so people do not know to protect themselves till it is too late) and 100% lethal cannot be mana... | [
"Highly lethal diseases tend to kill their host before the disease can be widely spread. Lower level diseases may travel more widely but do not (usually) kill their host.",
"Because of this. Think about something like a hemoragic fever virus (like ebola). Wipes out an entire village pretty rapidly, but never gets... | [
"Not a virus, but the amphibian chytrid fungus has wiped out entire species of toads.",
"http://en.wikipedia.org/wiki/Chytridiomycosis"
] |
[
"How do amino acids survive in meteorites?"
] | [
false
] | According to my understanding of panspermia, amino acids (along with other organic compounds) arrived on Earth via meteorites and thus jumpstarted the process of life. While I'm aware that amino acids aren't alive, how did they "survive" the journey? Wouldn't the heat from re-entry burn them all up? Wouldn't the vacuum... | [
"Objects flying through space are very cold, interstellar space cold, so they are frozen solid. The brief trip through the atmosphere only manages to sear the very outer layer. As for vacuum, amino acids are small molecule, cold and vacuum is a great way to preserve them. "
] | [
"Sure, any molecules reached by the heat can be modified, my point was that the rocks are so cold that the heat doesn't penetrate very deep into the structure. Much heat is lost to ablative cooling, like a returning Apollo capsule. The principle is the same."
] | [
"Would the extreme heat of re-entry modify the molecules in any way? Assuming they weren't frozen solid, of course."
] |
[
"Why while dreaming instead of finding the things that happen strange or illogical we feel them as normal?"
] | [
false
] | Well, I'm referring to those dreams where although there are strange scenarios or impossible/stupid situations we always find them to be normal, and it's not until we wake up that we realize those kind of things I tagged this as psychology, although I'm not really sure why. | [
"Well, dreams are very convincing. The same brain areas responsible for perceiving real sensory experience [e.g., hearing, seeing, feeling] are activated when we mentally imagine doing these things. So, the rouse is quite elaborate.",
"To add, when you are asleep, you have no context to determine the reality of y... | [
"Well, I will ask you then. If it felt like you were outside in your underwear, smelled like you were outside in your underwear, looked like you were outside in your underwear, and you had no reason to believe you were sleeping... And the experience was entirely devoid of context (no story leading up to it). What w... | [
"I don't the question was intended so much about why we don't realize we're dreaming, but why you can be in very strange scenarios and not ask yourself how you got there.",
"In the old cliche about going to school naked/in your underwear, people experience a lot of shame and humiliation, but they rarely doubt how... |
[
"Why are most of the Ice age relatives of modern animals so large?"
] | [
false
] | Animals grow large because the environment allows for it. I assume this means that food was plentiful during the ice age, yet the ice age seems an unlikely time for food to be more plentiful. Wouldn't the size of prehistoric animals be telling us that there was more food available than now since they were all much larg... | [
"Cool question! Terrestrial mammals got huge in the ",
"~35-40 million years following the Cretaceous-Paleogene extinction event",
". Based on increases in body size we see in the fossil record, mammals seem to have both a limit to how quickly they can increase their body size and a ",
"maximum body size",
... | [
"Where did you get that from? I didn't say anything about grazing. The amount of terrestrial land area is one possible factor in constraining maximum body size. "
] | [
"It may also have to do partially with the climate. Larger animals have a smaller surface area to mass ratio, and so retain body heat longer, other factors being equal. This would be an advantage in cold climates and a disadvantage in hot climates."
] |
[
"Can each personality in people afflicted by Dissociative identity disorder really have different illnesses ?"
] | [
false
] | I just watched a tv series where a person with Dissociative identity disorder had one of their personalities with miopia while none of the others needed glasses. Is this plausible? They mention it is possible for people with DID to manifest some diseases/symptoms only in one of their personalities. Is there any scienti... | [
"Myopia",
" is a physical problem with the eyes. The lens focuses incoming light improperly so that the focal point is in front of the retina rather than being directly on it. A person with dissociative identity disorder may have personalities that like to wear glasses, but from a physical standpoint, there is no... | [
"You are correct, stress is a potent physiological stimulator of many effects in the body. However, it is important to note that most of these effects you list are due to the fight-or-flight effects of stress hormones on the body. ",
"So, if one of these multiple personalities is stressed, this could cause a rele... | [
"Here is a link to four articles on DID and eyesight changes related to state changes: ",
"http://ge.tt/9quySAU1?c",
"\nTwo papers are very modern, and two are from the early 90's.",
"Here is a link to three papers on the forensic aspects of establishing a diagnosis of DID and differentiating it from factiti... |
[
"At what rate, compared to the speed of light, is the universe expanding?"
] | [
false
] | [deleted] | [
"This part",
" of 'A Universe From Nothing' by Lawrence Krauss answers your question in an eloquent way. I highly recommend watching the whole lecture, it's fantastic."
] | [
"The formula is v=Hd, where v is the velocity, d is the distance to an object, and H is the Hubble constant. This formula is exact, and it shows that they're always a point when your distance is high enough for v=c. So yes, distant parts of the universe are receding faster than light. Measurements show that this pr... | [
"Rephrase to help me understand better:",
"Space is expanding so fast that even though the sphere of the universe that we can see (\"observable universe\" is more eloquent, I guess) is expanding at the speed of light, we can actually see less stuff over time?"
] |
[
"Is it possible for planets with multiple moons to experience a simultaneous eclipse with more than one moon?"
] | [
false
] | [deleted] | [
"Read ",
"here",
" about a situation in which three of Jupiter's moons were in front of the Sun, relative to Jupiter, at the same time."
] | [
"It depends on what you mean by eclipse. In general, an eclipse is a specialized form of ",
"syzygy",
"), (there's a scrabble word for you), which can totally happen with 4 bodies: it just means \"bodies line up\". It's possible (for some definition of \"straight line\") for the two moons and the planet to alig... | [
"I suppose there's some sort of gravitational perturbations in a solar system that might cause the moons to orbit in some harmonic period (say, a 3:2 orbit, where one moon orbits exactly 2 times for the other one's 3 times) which would make it more likely. Slightly. It would still be pretty rare, however.",
"Not ... |
[
"The earths equator spins faster since it has to cover greater distance as compared to the pole. But as according to the Moment of Inertia theory the farther away something is from the axis the slower it spins, so the equator should spin slower. How do I reconcile these two ?"
] | [
false
] | null | [
"What do you mean by \"moment of inertia theory\"? When you have a rigid object rotating with angular frequency ",
", the linear velocity of a point ",
" (measured relative to the center of mass of the object) is ",
"x",
". So this increases linearly with r."
] | [
"v increases with increases with r. ",
"But due to conservation Angular momentum v reduces as r increases. How do i reconcile these two ?"
] | [
"The latter statement is not true. It sounds like you’re mixing up the relationship between linear and angular velocities with the common example of ice skaters changing their moment of inertia in order to increase their angular velocity.",
"For a given angular velocity, the linear velocity at some distance incre... |
[
"How do we know that quarks exist?"
] | [
false
] | null | [
"We can do ",
"deep inelastic scattering",
" experiments on nucleons and see that they in fact have substructure."
] | [
"Deep inelastic scattering tells us, roughly, that baryons have 3 point charges with fractional charges and mesons have 2 point charges with fractional charges. These correlate with the quarks found in the Standard Model."
] | [
"These correlate with the quarks found in the Standard Model.",
"That makes it sound like a coincidence. Isn't it more that the deep inelastic scattering results are the ",
" quarks are in the Standard Model?"
] |
[
"Will We ever see a star die? is there anyway to tell or could one day a star just blink out. What are the chances?"
] | [
false
] | I'm not very smart please don't ridicule me if i sound stupid | [
"There are two typical ends to stars' lives:",
"Supernovas, where the star blows itself apart in a final cataclysmic explosion. We see these explosions (in other galaxies) every day with modern survey telescopes.",
"White dwarfs,, where, the star has no more fuel and gradually fades away, as it cools. There i... | [
"What you end up with is called a \"Black Dwarf\". However, the universe is not old enough for this to have really happened yet, because it can take trillions of years for a star to cool down that far. But cool down they will, to a few degrees above absolute zero.",
"At that point, it would still be an object di... | [
"Supernovas take a couple of weeks to reach peak brightness. They fade away over a few months."
] |
[
"Do undersea creatures experience any sort of weather?"
] | [
false
] | On land there is wind, rain, snow, and more extreme weather such as floods and storms. Do ocean creatures experience anything analogous? Edit: Thanks for the great responses. | [
"Yes. Visibility under water changes constantly (comparable to \"under water storms\"), different algae bloom at different times a year - changing the eco system, water currents change temperature and oxygen levels. You can find \"dead water\" below water, which could be compared to - lets say deserts? The marine l... | [
"I can't speak to underwater phenomena, but sea creatures do respond to surface conditions. For example, ",
"some predators are drawn to tropical systems because the surface pressure brings prey closer to the surface",
"."
] | [
"There certainly is an fluid dynamics equivalence to 'weather' in the ocean. The ocean is full of eddies. They vary in size but 30-100 km is a typical range. The ",
"perpetual ocean animation",
" is a good visualization of the eddies. This is the ocean mesoscale and the eddies are ocean flows circulating arou... |
[
"For birds that fly in a classic V formation, are there birds that always fly on the left arm and others that only fly on the right arm?"
] | [
false
] | I'm assuming the birds, except the first, use their immediate neighbor to the front as reference, and I was wondering whether there is a type of "handedness" in birds where some like to have their neighbor in their right field vision (or others the left). | [
"No, they rotate. The V makes the air move in such a way that the birds in the back require less effort to fly than the birds in the front. Kind of like drafting in NASCAR. So every bird takes its turn at the front and then rotates through to the back to rest and recover "
] | [
"Who decides when to rotate? Can a bird cheat by shortening the time they spent in the front?"
] | [
"Yeah but I don't believe that's the question he's asking, I believe he is wondering if the birds alternate which line takes the point in the V. And if a bird crept to the front from the left side would it heavily prefer always flying on the left side. If this is a different worded way to say his question. All I ca... |
[
"Why aren't there any orbitals after s, p, d and f?"
] | [
false
] | After Element 60 I noticed that there weren't any new orbitals anymore, there were just "more of the others". Why is that? Anything to do with energylevels? | [
"There are. The orbital angular momentum quantum number can be anything from 0 to (n - 1), and n can be anything from 1 to infinity. The naming convention goes (starting from zero and increasing by 1 unit each time) like s, p, d, f, g, h, i, j, k, etc.",
"The problem is that we've only discovered 118 elements so ... | [
"We can produce atoms in high angular momentum excited states, yes."
] | [
"Because we forced it to be there in an experiment."
] |
[
"Is it possible to create an algorithm to give you a sum of the least possible combinations required to win in a lottery?"
] | [
false
] | Hello everyone, There is this game, called KINO and it looks kinda . It has 80 numbers, it "randomly" picks 40, out of which you can chose 20. There are 2 variations to play this. First one you can chose any 20 numbers you want and second method, is you get to chose either a) 5 columns or b) 4 lines or c) 2 lines + 3 ... | [
"If I understand correctly, if all 20 of your numbers are in the 40 chosen, you win?",
"If this is the case, then you are looking for the minimum number of 20-subsets F of [80]:={1,...,80} such that all 40-subsets contain at least one member of F.",
"This is the ",
"Turán number",
" T(80,40,20). The smalles... | [
"well I got more than I asked for. Thanks for your time to explain with such detail; even though I am not familiar with math at all, I can use common sense to figure you out. ",
"further brainstorm:\nSince I can chose either 5 columns out of 10, or 4 rows out of 8, how many tickets should I play to make sure tha... | [
"well I got more than I asked for. Thanks for your time to explain with such detail; even though I am not familiar with math at all, I can use common sense to figure you out. ",
"further brainstorm:\nSince I can chose either 5 columns out of 10, or 4 rows out of 8, how many tickets should I play to make sure tha... |
[
"[Medicine] How do diseases such as Duchenne and other Muscular Dystrophy types eventually become fatal? What is the actually cause of death?"
] | [
false
] | I don't know for sure if these types of questions are allowed, but I couldn't find a straight answer on google beyond vague heart conditions. | [
"The primary mechanism of death is usually respiratory failure (diaphragm and accessory muscles of respiration fail). As other here have mentioned, respiratory infections and comorbidities such as cardiomyopathies are certainly plausible and most likely quiet prevalent as well, but I don’t know the exact statistics... | [
"Very often, the cause of death is underlying heart and lung problems. Cardiomyopathy, for example, is a common cause of death. With patients who have trouble breathing or swallowing properly, they can be more susceptible to respiratory infections and pneumonia, even in the earlier stages. If you have muscle weakne... | [
"With MD it's usually a failure of muscles that support vital organs.",
"Breathing requires you to use your diaphragm. What's the diaphragm? A muscle.",
"Blood circulation and tissue oxygenation requires your heart to pump. What's the heart? A muscle.",
"These muscles are vulnerable to damage from MD in the s... |
[
"Why is the exhaust (CO) from a barbecue more toxic than the exhaust from a gas stove?"
] | [
false
] | Health officials are warning homeowners about the toxic effects of CO poisoning that can occur from using BBQs and industrial heaters inside the home. I understand that this isn't safe, but scientifically, why are typical kitchen gas stoves safe(r)? Does it have to do with the type/level of combustion? | [
"Gas gives you a hotter more complete burn so it gives off CO2, not CO. Gas is a gas and mixes nicely with air and so burns smoothly and so completely. Charcoal or wood is a solid and made of many things. It does not burn as hot, it does not burn as completely and so it gives off a variety of end products. "
] | [
"Two reasons: firstly, technology: the system is designed for a more optimal mixture of air and fuel than a couple of briquettes sitting in a BBQ (you could mitigate that a little bit by using a fan on the BBQ and getting it more oxygen so it can burn better).",
"And secondly, gas is famous for having reduced emi... | [
"No, they are equally dangerous for the same amount of gas consumed--however a stove has a flue designed to exhaust the waste heat and fumes outside.",
"There may also be a difference in the amount of CO produced from a natural gas stove and a LPG BBQ/industrial heater."
] |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"How do snowdrops reproduce? It's too cold for bees and they don't seem to throw seeds like dandelions so what is going on with snowdrops?"
] | [
"No. Artificial neural networks are explicitly modeled after brains, not the other way around."
] | [
"Isn't it weird how our brains are set up almost exactly like a neural network?"
] |
[
"Does HIV integrate INTO part of ovum and sperm cells?"
] | [
false
] | null | [
"If you're asking whether HIV infects gametes, the answer is no. It infects mainly a specific immune cell (CD4+ helper T cells). Free viruses are present in bodily fluids and this is what transmits the virus."
] | [
"Are there viruses that do integrate into the gametes?"
] | [
"None that affect humans, as far as I can tell. Here's an example of a virus that infects apricot gametes: ",
"pdf"
] |
[
"Is intergalactic space different from interstellar space?"
] | [
false
] | I'd imagine the density of matter and radiation (excluding dark matter) would be much much lower than interstellar space, or almost completely empty of it. Also, is there a possibility that rogue planets or stars exist in intergalactic space? | [
"Interstellar space is almost always within the confines of a single galaxy. Runaway stars definitely exist, though they are rare -- sometimes interactions with other stars in a galaxy can cause a slingshot effect to give a star very ",
"high velocities",
" -- see Hypervelocity Stars in that link. Runaway sta... | [
"You are right in that the density is much lower in intergalactic space.",
"The density of matter in our Galaxy is about 1 particle/cm3 (in the disk, with the halo being less dense). The density of matter in intergalactic space (between galaxies) is about 2 x 10-31 gm/cm3, mainly hydrogen. At these densities, I d... | [
"Those points about hypervelocity stars and void galaxies are incredible! \nAre rogue star lifespans affected in some way because they are extragalactic? ",
"Also, are there any recorded/imaged runaway stars, or are they just a probable theory?"
] |
[
"What does the bacteriophage do once it injects it’s DNA into the host cell?"
] | [
false
] | For example, the bacteriophage T4 inserts it’s DNA into the E. coli and the virion stays outside of the cell. Are there DNA cells left within or does the cell just die? I’m thinking if it does die it’s a small sacrifice since many more virions will replicate within the host and eventually burst. Thank you! | [
"you’re personifying the virus a little too much. the virus and the cell don’t ‘do’ anything, they’re controlled by the laws of physics and chemistry. ",
"think of the virus as a piece of rogue dna. it starts by borrowing the cells machinery to make viral proteins that self assemble into capsids and such which ... | [
"T4 codes for two enzymes, the products of the t and e gene. The t product is a holin that mediates the transfer of the e product, a lysozyme, to the cell wall. The lysozyme then degrades the peptidoglycanes of the cell wall, as per usual lysozyme action. ",
"https://www.sciencedirect.com/science/article/abs/pii/... | [
"Viruses aren’t exactly alive. They don’t consume energy and grow and replicate themselves. The protein envelope basically attaches itself injects the DNA, the cell does all the work. The original envelope dissolves I guess. ",
"But it isn’t a sacrifice really, it is not a parent child relationship, rather closer... |
[
"Is a bussard ramjet efficient enough to be feasible?"
] | [
false
] | [deleted] | [
"Ooh time for math! Clearly this calculation has a thousand engineering flaws, but maybe decent enough to get the idea...",
"Protons per m",
" per second, at 0.1c:",
"Energy per proton:",
"Power per m",
" of fuel intake:",
"Force needed to produce an acceleration of 9.81 m / s",
" on a 1e4 kg spacecra... | [
"Bussard ramjets are fantasy, they generate more drag as a magsail than they can generate from fusion. Worse yet, they require extremely, extremely advanced fusion reactors, far beyond anything we are likely to be capable of in the near future (either orders of magnitude higher plasma temperatures or orders of magn... | [
"Not that it matters anymore, but here's the calculation of the drag.",
"Mass of proton:",
"Kinetic energy of proton at 0.1c:",
"Kinetic energy obtained via fusion per proton (assumptions the same as my original post):",
"The delta works out to 3.19 × 10",
" joules, so you're wrong, but only just. I'm sur... |
[
"Are tectonics a prerequisite for volcanism?"
] | [
false
] | Can volcanism occur on celestial bodies that do not have active tectonics? | [
"Plate tectonics are not a prerequisite for volcanism. ",
"Plate tectonics are only known to operate on Earth, yet there is well documented evidence of volcanic activity on Mars, on Venus and on Io. ",
"In the case of ",
", the absence of plate tectonics and much thicker crust has led to a few incipient faile... | [
"Tectonics are not strictly necessary. Tectonics contribute to volcanoes (see subducting tectonics) but other events like upwelling of hot spots (see Hawaii) can also produce volcanoes. ",
"As long as there is a hot core and convection of the mantle, there is a possibility for volcanism. "
] | [
"I see. But the convection of the mantle does not bring about tectonism? Are the convection currents simply not \"strong\" enough to rift and subduct overlying crustal rock?"
] |
[
"My father doesn't believe we can tell how far away a star is using science; How can I prove this to him?"
] | [
false
] | My father likes to exclaim to nearly everyone his misconceptions and distrust of science at social events. Is there a way I can show him how we can determine the distance of a star? Hands on would be more interesting. I hope this question isn't in the wrong spot, thanks. | [
"Take him out to a football field or something, or measure a very far away object using the same methods astronomers use to determine star distances and show him how it works. Then, drive out out or walk out to the object and measure the distance."
] | [
"not really. If you're using parallax it's pretty straight forward:",
"http://www.ifa.hawaii.edu/users/mickey/ASTR110L_S04/parallax.html"
] | [
"On phone, but wiki cosmic distance ladder. Also parralax"
] |
[
"Why is the nearest star so far away?"
] | [
false
] | The nearest star, Proxima Centauri, is 4.2 light years away. AU = distance from Earth to the Sun 1 light year = 63,241.1 AU So Proxima Centauri is 265,612.62 AU away. (I hope all this math is right) To put into perspective, Voyager 1, launched in 1977 and the farthest man-made object, is only 142 AU away from Earth. So... | [
"There's no strict rule for how far apart stars need to be. They can have close encounters, and you can have even two or more stars in the same system. If they're ",
" close they start to interact and one strips material off the other, but that's like well within the orbit of Mercury.",
"The bigger issue on thi... | [
"There's an ",
"anthropic",
" argument: planets in regions of high star density are likely to be very hostile to life.",
"Stars are constantly in motion relative to each other, under the gravitational influence of everything around them. Close encounters from neighbouring stars can scatter asteroids or comets... | [
"It is not a coincidence. Closer to the center stars often have close fly-bys which change the orbits of their planets, that makes the region quite bad for life."
] |
[
"How does one's brain create a picture and can that process be replicated using computer algorithms?"
] | [
false
] | I just looked out the window and noticed a full moon. I looked sharp and detailed. I picked up my phone and took a photo but I knew right away it wouldn't turn out. A white dot with a blurry mesh that is my window screen. Somehow, my brain is able to ignore the screen and using a variety of angles, create a mental p... | [
"we can ignore for now that your brain doesn't in any sense 'take pictures', and that what it does has very little similarity to the operation of a camera (or of a display screen).",
"here are a couple of crucial ",
" between human vision and your phone camera/display that more-or-less answer your question:",
... | [
"Thanks for the information. I did some reading based on your answer and I believe this is a situation where we will be able to do it programmatically before we really understand how the human mind does it.",
"I started down the path of compressed sensing and quickly realized that the easy part is filling in the... | [
"This particular problem is not very well understood. Many believe that the brain operates using \"compressed sensing\" algorithms -- namely, that certain features about objects you perceive, such as edges, shapes, and primitive object representations, are coded in a type of \"alphabet\" in visual cortex -- referre... |
[
"Does your body build up a resistance to caffeine?"
] | [
false
] | [deleted] | [
"Yes, it does. Caffeine works by blocking the action of ",
", which is an inhibitory neurotransmitter (i.e. nerves release it into synapses to reduce the likelihood that nearby nerves will fire). By blocking adenosine, caffeine stimulates activity.",
"But, like pretty much all systems in the body, the adenosin... | [
"Interestingly, chronic sleep restriction also up-regulates adenosine receptors, making you more susceptible to the effects of the circulating adenosine molecules. In that respect, there are similarities between the long-term effects of caffeine use and sleep restriction on the adenosine sleep-regulatory system."
] | [
"Yes, it is possible to build a caffeine tolerance over time. Like many mind-altering chemicals it is possible to even become dependent of caffeine, though the withdrawal symptoms are far less severe than those of other stimulants (like nicotine). The way caffeine works is by blocking* a neurotransmitter called a... |
[
"When you press on your eyes while they are closed, patterns and colors are seen. This is most prominent when performed in a dark room. What is the cause of this phenomenon and does it have a name?"
] | [
false
] | null | [
"Not quite. The photoreceptors (cells that respond to light) in your eye will also respond to pressure. So applying pressure to the front of your eye, also applies it to your retina, which makes the photoreceptors respond in weird ways.",
"It's called a ",
"phosphene"
] | [
"Not quite. The photoreceptors (cells that respond to light) in your eye will also respond to pressure. So applying pressure to the front of your eye, also applies it to your retina, which makes the photoreceptors respond in weird ways.",
"It's called a ",
"phosphene"
] | [
"That's a great question. I don't know why yours are blue, but I would be surprised if that were universal.",
"Two potential factors:"
] |
[
"Is there an increased rate of cancer in athletes who get routine MRIs, etc?"
] | [
false
] | As an NBA fan, I feel like many players are consistently getting MRIs, Cat Scans, Ultrasounds, and surgeries in the offseason. Does this have any long term effects such as an elevated rate of cancer? | [
"Since no one has answered this yet, I'll answer the MRI part.",
"MRI - no. MRIs generate a magnetic field (if you've ever been in one, they ask very seriously if you have any ferrous (magnetic) metal implants in your body). Said magnetic field measures blood flow to a region. The field affects the iron in you... | [
"I think the risk is over-state here. ",
"Here",
" is a chart that shows you the radiation you get from a CT scan of different regions of the body.",
"This",
" article posits that the best curve fit to model stochastic effects of ionizing radiation is to use a linear model, with a slope of 5.5% increased c... | [
"Thanks for your time answering this question. Great answer"
] |
[
"If we \"listen\" to smells by reading the vibration of the molecule, is it possible to dismiss the \"Lock and Key\" explanation altogether?"
] | [
false
] | As far as I know the way in which we smell is a harmonious process between the particle fitting a receptor, and then furthermore recognizing the vibration of the molecule to trigger the receptor. My question is if it could be possible that like light and sound, there is a wavelength spectrum for smells and our noses si... | [
"Not all together. Luca Turin studied this. You can mimic the scent of something with a molecule of quite different structure but similar vibrational modes. And on the other hand, some molecules of virtually identical structure end up smelling nothing alike. Here is the ted talk, it's older but a great presenta... | [
"Thanks a lot that was really helpful. "
] | [
"It's worth noting that although Turin's explanation is really interesting (and I really think he's on to something personally), much of this is just unknown and Turin's theories are quite controversial.",
"The scent receptors in our nose are membrane-bound and they are very difficult to study via techniques like... |
[
"Is alcoholism really a disease?"
] | [
false
] | I know people can be reliant on alcohol, but it's my limited understanding that it doesn't actually affect nueral pathways like, say heroin. What's the story? | [
"It ",
" affect neural pathways. What do you think getting drunk is?",
"The most active psychoactive ingredient in alcohol is ethanol, which interacts with a TON of different neurotransmitters in the brain. The biggest one is called GABA (one of the two main neurotransmitters in the nervous system), but it also... | [
"Just to clarify a little point: NMDA is a type of glutamate receptor, not a neurotransmitter per se. Glutamate is the actual neurotransmitter. "
] | [
"Ah--good point. Yeah, that was not phrased well in my original post. Thanks!"
] |
[
"What color would radon glow in a gas-discharge lamp?"
] | [
false
] | This has been asked here before, but I've not yet seen a satisfactory answer...so here it goes again: What color would radon glow in a gas-discharge lamp? (I'm aware of the practical difficulty in setting up a real-world radon gas-discharge lamp). I have a small project in which I'm using colored pigments to represent ... | [
"The visible emission spectrum of radon is given here: ",
"https://physics.nist.gov/PhysRefData/Handbook/Tables/radontable3.htm#4349.60",
"Of course, luminescence from ionization due to radioactive decay would probably overwhelm this.",
"See also: ",
"https://www.reddit.com/r/askscience/comments/41rly1/what... | [
"Actually technically it isn’t the ionization itself that produces the luminescence but the electronically excited states falling back to their ground state where a photon of equivalent energy is released due to conservation of energy. \nYou can electronically excite already ionized gas of course since the accelera... | [
"Electronically or electrically excite? Not trying to be a smartass, actually curious."
] |
[
"Why is beer foam white, and not the same colour as the beer?"
] | [
false
] | null | [
"the light is scattered through the thin film of the bubbles, causing it to look like a homogeneous white."
] | [
"And to tack on, this phenomenon is called ",
"Mie scattering",
". It also explains why clouds are white. This occurs when scattering is due to particles of a size similar to the wavelength of visible light. "
] | [
"Keep in mind that the Mie scattering is not due to the radius of the whole bubble, rather, it is induced by the thickness of each bubble's film."
] |
[
"What are the current limitations to present day renewable energy sources, and also future renewable energy sources still being developed?"
] | [
false
] | null | [
"Your question may be too broad or open-ended to get the type of answers you want. Anyway,",
"Wind power: requires wind (so load factor can vary drastically). Long-term potential is ~5X current global production, but requires many offshore wind turbines.",
"Hydro: requires damming water (can harm ecosystems, di... | [
"I would say that conserning variable renewable energy (solar, wind), the current limitation is the inability to affect production times. This will become less and less important in the long term future, but more and more so in short term.",
"Hydro power probably suffers most from lack of new and sustainable loca... | [
"All renewable energy comes from the sun. Wind, hydro, biofuel, and solar all are produced by the energy of the sun hitting the planet. So the upward limit is the amount of solar energy that strikes the earth.",
"The sun delivers more solar energy in an hour than all the humans on the planet use in a year, so w... |
[
"I know it's fundamentally impossible to travel faster than c per se, but are there ways around it?"
] | [
false
] | The best example I can come up with comes from Madeleine L'Engle's "A Wrinkle in Time." I know the word "tesseract" really means "hypercube," but I'm inquiring about the concept she puts forth, never mind her vocabulary. Obviously we don't have the technology right now, but I'm wondering if it's theoretically possible ... | [
"The closest thing to a formalised version of tessering is the Alcubierre Metric, a solution to Einstein's equation that tries to recreate warp drive. It is physically unrealistic because it necessitates construction from material with negative mass, which does not exist. Same goes for wormholes."
] | [
"It's really funny to say one knows that something is ",
" impossible, but then try to get around it. It's fundamental. There are no ways around it by definition.",
"But I get it. You ",
" want to believe that some day we'll be able to go to distant planets and then come back and tell everyone on Earth about ... | [
"When are one of you physics guys going to write up a FAQ for this and related questions? I feel like I read it 3 times a day. ",
"You could entitle the faq \"You can't go faster than c, so stop asking\" or something useful like that."
] |
[
"Are we breeding any new fruits, vegetables, or are capped out?"
] | [
false
] | Are we growing any new fruits and vegetables, like we have pears and tomatoes, or are there no new lines of fruit and vegetable being bred | [
"We indeed are. ",
"Israel seems to be at the forefront"
] | [
"I take this for granted, but its insane that we are still making, creating new types of fruits. For some reason its weird to think about, but its how it always has been I guess."
] | [
"What is dreadfruit? The reason why I am asking probably why I can't find it. "
] |
[
"Is it possible to find a basis for the set of continuous functions?"
] | [
false
] | Following up on this, do infinite dimensional vector spaces necessarily have a basis? | [
"Given a vector space ",
" over some field ",
", it's important to distinguish between two types of basis:",
" A subset ",
" ⊂ ",
" such that any vector ",
" in ",
" can be written as a unique ",
" linear combination of elements of ",
". This is also called an algebraic basis.",
" For this type ... | [
"For one, if V is not finite-dimensional, then the Hamel basis B must be uncountable. So there are no vector spaces with a countably infinite Hamel basis.",
"Maybe I'm missing an implied condition here, but the vector space of real polynomials has a countable basis."
] | [
"Thanks for the detailed reply! I've only started a higher level linear algebra class and a real analysis class this quarter, so the topology parts went slightly over my head, but I've saved the post for future reference. "
] |
[
"Are Wireless transmitters different in space?"
] | [
false
] | null | [
"They function in pretty much the same way. If there's no air, then signals will travel slightly further before losing energy due to absorption, but this effect is very small for transmitters that are designed for short range use, like Bluetooth and wifi."
] | [
"The difference is extremely small."
] | [
"That’s pretty cool!! So a stronger signal exist up there?"
] |
[
"This sounds stupid but, how does water(puddle, wet clothes) dries out without reaching its Saturated Temp (100 deg C)?? Does evaporation occurs in the drying process?"
] | [
false
] | null | [
"For a given temperature, liquid water (or solid, don't worry about this for now) has an equilibrium vapor pressure. Below this pressure, water will evaporate to meet it, above this pressure water condenses out of the air to lower itself. At exactly equilibrium, the water condensing is matched by the water precipit... | [
"Not a dumb question! It's perhaps one of my favorite questions to ask folks because it requires some deep thinking.",
"Evaporation must be treated as a ",
" effect. Water in the liquid or gas phase at some temperature T doesn't mean all those molecules moving around with the same energy, some are more energeti... | [
"Ah- I should be clearer. We care about the partial pressure, that is to say the pressure due to water vapor, not the total pressure of all gasses. ",
"So at 24C, if the humidity outside is less than 100%, it will dry. ",
"This is what % humidity is- the fraction of the saturation partial pressure for the given... |
[
"Could a computer in our universe theoretically contain enough information to exactly simulate our own universe?"
] | [
false
] | ...or is this computationally impossible? In theory, if it was true, couldn't you build another computer inside of it, and have infinite storage space? How much data is in our universe? | [
"I'm not sure it would be possible - wouldn't you need more than one particle to store the information about a single particle, hence you'd need a computer bigger than the universe is in order to model the universe?",
"Then there's another problem that just occurred to me - if the computer you were using to model... | [
"If the computer is ",
" our universe, then it has to be simulating itself as well. "
] | [
"What if the computer were to model everything from big bang up to the point of its creation? Does this simplify the problem if it does not have to model itself?"
] |
[
"Why do matches give off a lot of smoke immediately after you blow them out? And not before?"
] | [
false
] | null | [
"Assumptions: Wooden match, burned past the point where the chemicals that are added to the tip have essentially burned away already.",
"The smoke you see is a mixture of vaporized wood gas (assuming a wooden match), charred cellulose, and water from the combusion (and like a hundred other byproducts of combusti... | [
"You mean half-burned solid fuel particles (soot) and liquid water droplets (steam) and not gas. Smoke is composed of suspended soot and not gas. Most gases are invisible while soot and steam are not. If you properly premix the fuel and oxidizer in combustion, there is complete combustion and therefore no smoke. "... | [
"When a match has burnt down past the igniting chemicals, the heat of the flame is pyrolyzing the cardboard/wood stick... It is breaking down the organic compounds into gases. You don't see them because the flame then burns them up into carbon-dioxide and water vapor. When you blow the flame out, the gases conti... |
[
"After keeping a water bottle in the freezer, it rapidly turned from liquid to slush as soon as I unscrewed the top. What happened, chemically?"
] | [
false
] | [deleted] | [
"Like this?",
" I believe the term is ",
"supercooling",
"."
] | [
"The water was supercooled.",
"Here's a video of what you saw:",
"https://www.youtube.com/watch?v=pTdiTe3x0Bo",
"And the wikipedia entry:",
"https://secure.wikimedia.org/wikipedia/en/wiki/Supercooling"
] | [
"Awesome, this is almost exactly what happened to my bottle. Thanks to both you and pizzza"
] |
[
"Why do girls reach sexual maturity before their bodies are ready to bear children?"
] | [
false
] | There are many health risks associated with pregnancy and childbirth, particularly below the age of 15. Yet, many girls become fertile well before that age (average is 12.6 years). While I know early puberty is probably an artificial problem, I assume this does not account for the differential between the 'ideal' age f... | [
"There are many health risks associated with pregnancy and childbirth, particularly below the age of 15.",
"There are many health risks (to both mother and baby) also associated with giving birth after the age of 35. Yet many older women do get pregnant and deliver healthy babies.",
"In terms of biology, there ... | [
"Your \"non-optimal\" category is not balanced in terms of fitness consequences, though. A woman in her forties may have already had several children during \"optimal\" years, so any additional children are pure fitness benefit even if the health risks are high and probable, so there's little selective pressure aga... | [
"One the other hand, a girl who becomes pregnant before her optimal years and either dies or becomes infertile as a result attains a fitness of 0, so that ability would be highly selected against unless the danger is fairly small.",
"The danger is indeed small.",
"In developed countries, maternal mortality for ... |
[
"Air injected directly into your blood stream can be lethal. How does your body not get air inside your blood vessels when you bleed?"
] | [
false
] | null | [
"Small air amboli typically get transported to larger veins, to the heart and then to the lungs where they get stuck. The air can then diffuse into the alveoli and is exhaled. Oxygen and CO2 would get absorbed into the blood before this to a large extent, leaving mainly nitrogen in the remaining bubbles."
] | [
"Does that tiny amount of trapped air go away eventually? And if so, where to?"
] | [
"Does that tiny amount of trapped air go away eventually? And if so, where to?"
] |
[
"Hydrogen filled balloons"
] | [
false
] | If a regular party balloon were filled with hydrogen, and said balloon was then shot, would the friction of the bullet cause the hyrdogen in the ballon to ignite, producing a small explosion? Is so, where can I acquire compressed hydrogen? | [
"According to Wikipedia the autoignition temperature of hydrogen is about 1000 degrees Fahrenheit. According to the first google hit, bullets are about 500 degrees Fahrenheit. So I'd say no. There may be some factors I'm not taking into account."
] | [
"Not only is the temperature not high enough, one has to take into account of heat as well - is there enough energy to raise the temperature of the gas to the autoignition temperature?",
"This is the reason flicking a cigarette into a pool of gasoline can't set it on fire. The temperature of burning tobacco is hi... | [
"One thing to note is that a balloon filled with ",
" hydrogen won't \"explode\", but rather will make for a relatively slow (~0.25 second) burning fireball. To get a big bang, you have to mix in some oxygen or air. This is because the pure hydrogen won't burn without oxygen, and has to mix with surrounding air... |
[
"AskScience Cosmos Q&A thread. Episode 5: Hiding in the Light"
] | [
false
] | Welcome to AskScience! If you are outside of the US or Canada, you may only now be seeing the fourth episode aired on television. If so, This week is the fifth episode, "Hiding in the Light". The show is airing in the US and Canada on Fox at Sunday 9pm ET, and Monday at 10pm ET on National Geographic. Anyone can ask ... | [
"Light moves at c in a vacuum! It can be slowed down by all sorts of matter!"
] | [
"Why is red light hotter than blue light if blue light has more energy?"
] | [
"So, while the other answers were .. saying accurate things for the most part, they didn't seem to answer your question directly.",
"The answer is that the materials that we used to measure temperature and our own skin, etc. these materials preferentially absorb red more than they will absorb blue. ",
"To see t... |
[
"[biochem] Why in citrus fruits, like clementines, are the inside separated into sections?"
] | [
false
] | Please be as elaborate as you can be! I'm a biochem student currently so around that level would be prime : D Thanks!! | [
"No offense to Kyle772 but that answer is pretty inaccurate.",
"Oranges have sections because these sections have evolved from other fruit plants preceding citrus. I'll attempt to break it down for you as a bio undergraduate:",
"Plants produce fruits (which contain the seeds) to give the developing embryo an ab... | [
"We sure do, and as a genetics student I should remember details but here's a pretty simple explanation:",
"It's all a matter of evolution. I showed that fruits come from flowers. Well, flowers have a genetic basis for their development, meaning that the effects of certain DNA sequences on competing chromosomes i... | [
"the nutritional and economic value of these foods has been augmented by ",
" for more agricultural efficiency",
"It might be nitpicking, but that would be artificial selection."
] |
[
"Would it be possible to pump nuclear waste into a really deep oil field that has run out of oil?"
] | [
false
] | I am completely ignorant of the engineering issues involved, but it seems that liquefying the nuclear waste and then pumping into an empty oil or natural gas field doesn't sound too far away from being possible. If the oil field is below the water table, does it matter if the nuclear waste seeps down below? In what way... | [
"The problem is more complex than that. For starters though, it wouldn't matter what physical form the waste is in (solid, liquid, primordial ooze) since what we are dealing with are decay products, not physical containment of matter problems. Placing \"nuclear\" waste (radio actively decaying material or materials... | [
"a) Nuclear waste is solid not fluid (e.g. spent nucelar fuel rods). So no pumping. The solid spent fuel rods are often stored in water, for cooling and temperature management purposes. ",
"http://en.wikipedia.org/wiki/Spent_nuclear_fuel",
"b) The US's current planned storage facility for long-term storage of n... | [
"The real issue with what we think of as nuclear waste is that a lot of it is actually really ",
". I mean, it's chock full of uranium and plutonium, two extraordinarily rare and useful elements. If it wasn't full of those, then we could store it anywhere, because what's left isn't all that dangerous.",
"Due to... |
[
"Will there ever be a sorting algorithm that beats O(n log n) in the average case?"
] | [
false
] | Not counting radix sort, since the number of keys won't ever be less than log(n). I haven't taken any in-depth courses about the mathematics of algorithms; has anyone proven that O(n log n) can't be beaten, or has nobody just done it yet? | [
"Also note that this bound is for comparison sorts. For sorts that don't actually compare things, like ",
"radix sort",
" for example, we can get worst-case linear performance."
] | [
"There's a formal proof that any sorting algorithm will need at least O(n log(n)) comparisons in the worst case, so that will never be beaten. You may find that proof in several algorithms books, but googling I found this: ",
"http://ijcsi.org/papers/4-2-25-30.pdf",
"However that tells us nothing about the aver... | [
"There is an Omega (not-big-oh, technically in this case) (n log n) lower bound on the average case, too. Assuming that all keys are distinct, and all input permutations equally likely. "
] |
[
"what would happen if a healthy (stable) person took a shot from an EpiPen?"
] | [
false
] | null | [
"Elevated heart and respiratory rate, mostly.",
"It actually happens more than you'd think. Plenty of badly trained first aiders (or properly trained first aiders acting under intense stress because they are aiding someone they care about) inject themselves with the stuff by accident. The most common mistake is t... | [
"I've been told there are varying levels of psychological response, but i've never experienced epinephrine injection myself. There seems to be an issue with differenciating between the true effect of the substance, and the sudden panic attack people can have when they accidentally inject themselves with something s... | [
"I've been told there are varying levels of psychological response, but i've never experienced epinephrine injection myself. There seems to be an issue with differenciating between the true effect of the substance, and the sudden panic attack people can have when they accidentally inject themselves with something s... |
[
"Question about pressure, oceans, and caves."
] | [
false
] | Say I take a submarine to the bottom of the ocean and park it in cave. If I get out of the sub into the air of the cave, will the pressure kill me? Is the pressure the same as the water? | [
"Good to know! I'll take my sinister underwater laboratory plans elsewhere."
] | [
"You mean there is air trapped in the underwater cave. Then yes the air pressure is the same as water at that depth. "
] | [
"Is the pressure the same as the water?",
"yes",
"will the pressure kill me?",
"Directly or indirectly, yes. I'm assuming by \"bottom of the sea\" you mean great depth, certainly more than 100 meters. That depth will kill you. ",
"First off, if your sub is at surface pressure and you are at great depth, you... |
[
"Now that SHA-1 has been broken, what would it take for crackers to break SHA-256 or SHA-512? Is it just a matter of processor time?"
] | [
false
] | It's been broken: They recommend moving on to SHA-256 or SHA-512: We hope our practical attack on SHA-1 will increase awareness and convince the industry to quickly move to safer alteratives, such as SHA-256. But if the algorithm is basically the same and only the block size changes, why is it safer? Is it only because... | [
"SHA-1 has not been broken. A single collision was found, using 6500 years of CPU time (or 110 years on a GPU), and a technique which is about 10",
" times faster than brute force. To turn this into a practical attack, you need to find a collision with what you're trying to spoof, that ",
" delivers your payloa... | [
"A hash is an algorithm that turns some data into a digested form, that can't be reversed. Here's a really stupid one:",
"We assign numbers to letters. a=1, b=2, c=3. The hash is just adding them all together. So hash(abc) = 1+2+3 = 6",
"A collission is where two input values produce the same result. So hash(cb... | [
"Yes.",
"The thing is that in a good hash function, finding the same hash as for another piece of data, or generating a piece of data that corresponds to a given hash is really, really hard and doable only by brute force.",
"SHA1 is 160 bit. On average you'll have to search half the space until you had a match,... |
[
"Am I Understanding This Correctly About Ionizing and Nonionizing Light Particles?"
] | [
false
] | null | [
"6 GHz is not ionizing."
] | [
"My understanding is that higher frequencies starting around UV spectrum are ionizing particles that can strip electrons from atoms causing havoc to human DNA and cells. If the lower frequencies are unable to interact with cells then the only issues I can think of would be heat at higher amplitudes.",
"This is co... | [
"I'm not aware of any scientific basis for those concerns."
] |
[
"Does the spin of unpaired electrons effect an atoms properties?"
] | [
false
] | I know electrons are slotted in atoms in different orbitals described by 3 quantum numbers, namely the principle quantum number (n), the angular orbital momentum (l), and the magnetic quantum number (ml), which describe energy, shape, and orientation respectively. These give rise to the orbitals and their classificatio... | [
"Main thing is the magnetic moment. The carbon atom can be in a triplet state in which the spins add up or in singlet states where they cancel. This will also affect the absorption spectra. And it will influence chemical reactions."
] | [
"Any unpaired spins will contribute to the total angular momentum of the atom."
] | [
"It's less about the specific spin and more about the comparison of a spin to other spins in a given frame of reference as alluded to by the answers above. The +1/2 -1/2 designations are arbitrary and have no intrinsic difference except that they are different from each other. "
] |
[
"How does light pollution drown out the stars in the sky?"
] | [
false
] | [deleted] | [
"Yes, it is manmade light from the surface goes up, bounces off the atmosphere, clouds, smog, etc and comes back down in a vague glow that makes the entire sky brighter. The \"black\" of the night sky is no longer black, it is brighter. The stars that are fainter than that brightness are drowned out because their l... | [
"Its the same reason why the sky is blue, only in reverse somewhat. \nCheck out Rayleigh Scattering:\n",
"http://en.wikipedia.org/wiki/Rayleigh_scattering"
] | [
"Go to a foot ball stadium at night (make sure the huge stadium lights are turned on). While looking directly at the stadium lights have a friend stand on top of those lights and point a standard flashlight at you. Yeah, you wont really see the small flashlight. there is a lot of artificial light that over powers t... |
[
"Why is chest hair more common in some parts of the world and not others? What areas are those and what evolutionary conditions do they have in common?"
] | [
false
] | [deleted] | [
"Couple of things I'd like to add to what people have already said:",
"First, asking why people have \"more\" or \"less\" chest hair (or body hair in general) creates the wrong impression. The density of hair follicles (number of hair per unit area of skin) is pretty much the same in all people (and between men a... | [
"This is speculation",
"Please don't. Leaving a question unanswered is better than possibly giving a wrong answer. ",
"AskScience guidelines"
] | [
"This is speculation",
"Please don't. Leaving a question unanswered is better than possibly giving a wrong answer. ",
"AskScience guidelines"
] |
[
"How did burying or burning our dead become a common practice among most cultures, even isolated ones?"
] | [
false
] | null | [
"Bodies that are not buried or burned tend to smell bad and have diseases. People that did not bury or burned their dead probably got those diseases.",
"Add to that the emotional connection between the still living and the recently deceased - of course you wouldn't want a loved one to be desecrated by an animal -... | [
"Bodies that are not buried or burned tend to smell bad and have diseases. People that did not bury or burned their dead probably got those diseases.",
"Also attract predators....something that would not be welcome by prehistoric humans who were not exactly at the top of the food chain back then."
] | [
"And also, death rituals are usually very traditional, and on the timescale of centuries, very few human civilizations are completely isolated."
] |
[
"Why do we try to lower fevers if it helps kill/slow down the reproduction of bacteria/viruses?"
] | [
false
] | Here's how I see it. Today, everyone gets fevers, which means evolutionarily speaking people who got fevers were favored to live over people who didn't. I understand that many people have died from fever, but I also think what I previously stated proves that even more people would die if they didn't get fevers. So, why... | [
"We treat fever because high fevers can cause brain damage and systemic dysfunction. Infections are more safely treated with antibiotics than and extremely high fever."
] | [
"it is rare for a moderate fever to cause brain damage and systemic dysfunction, and in most cases treating a fever is done because of the symptoms a person experiences when there core body temperature is raised (sweats, chills, malaise etc.) - even though it may result in a slightly impaired response to the infect... | [
"Right really high fevers can kill you and most fevers are generally uncomfortable. While fever is an adaptive immune response, medical science has come out with drugs that are way more effective than fever at dealing with infection, so we don't have to experience discomfort/risk of death anymore."
] |
[
"Does the body get water from metabolizing carbohydrates, and if so, does it use it?"
] | [
false
] | I remember from my science classes that most carbohydrates, when burned completely and in theory, create only carbon dioxide and water. Obviously we get the dioxide part and we excrete it through breathing. But does the body still get water from that reaction (no matter how minute the amount), or is it compounded into ... | [
"Yes, your body generates water as you said. However, as humans, we need a lot of water. The amount of water generated by carbohydrate breakdown is relatively small compared to the needs a person has.",
"Other animals, such as the ",
"kangaroo rat",
" don't need to drink water to survive, and instead acquire ... | [
"In fact, an average adult produces about a liter of water a day from this source."
] | [
"Now is that strictly carbohydrate breakdown? Or does that include inherent water content of the food?"
] |
[
"How do super storms like Hurricane Dorian affect marine life as the storm travels through the area? Do they affect deep sea creatures?"
] | [
false
] | Edit: Thank you, anonymous do-gooder for the gold! They say it is better to give than to receive, but this is my first gold so I gotta say this feels pretty darn good! | [
"I am writing a PhD thesis on the ocean response to tropical cyclones. Contrary to what some people have suggested here, the energy of cyclone (hurricane) winds powers ocean currents well over 100 meters below the ocean surface. This has been observed directly using autonomous ocean profilers that measure temperatu... | [
"Large storms like Dorian with high winds cause a mixing of the nutrient-poor surface layer with slightly deeper, nutrient-rich waters, bringing nitrogen, phosphorus and trace metals to the sunlit photic zone which can cause phytoplankton blooms and subsequent zooplankton blooms, which then attract larger predators... | [
"I bet you’ve been waiting in anticipation for this sort of question to be asked! (I’m working on my masters thesis so i know how excited I’d be to get the opportunity to talk about my research) ",
"fascinating answer, thanks for sharing!"
] |
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