title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How fast can a PC boot?"
] | [
false
] | Hi, Are there any PCs that boot to the OS in 1-2 seconds? On my machine (i7 + SSD) it still takes 10 seconds to get to the login screen. Where's the bottleneck in the current techology? And what would it take to make a machine that can boot really fast? Thank you! | [
"loading the kernel (and other associated important things) from disk to memory is the major bottleneck. There are also hardware checks (which you can usually disable in the BIOS) which may take small amounts of time.",
"That said, you can load an OS in a VM almost instantly, if the OS pages are already in RAM. F... | [
"What operating system you're using? ",
"The bottleneck almost certainly is within loading of your kernel.",
"My main laptop (has cheapest SSD I could find, I use Linux with standard newest stable kernel) boots in under 4seconds. I know I can scrape off at least 1 second of it by changing some stuff... but why ... | [
"Strictly speaking, the bootstrap process ends when the BIOS transfers control to the operating system. It's a very quick process that will happen before you even see the OS splash screen.",
"At least in PCs, the way in which control is transferred is reading the first 512 bytes (the first disk sector) of the dev... |
[
"If space is in fact quantized, then mustn't there be such a thing as an absolute spacial reference point?"
] | [
false
] | null | [
"Not at all. Imagine - for a moment - that the universe is like a loop of chain where every individual link is the same. Clearly this is quantized by chain links, but if you move one link forward - or back - you can't tell the difference.",
"It's also worth noting that 'quantized space' doesn't meant there has... | [
"No. The integers are discrete (quantized). If you set up a number line of integers from -infinity to +infinity, you can shift 0 to wherever you want it. ",
"Add five to every number on your number line, and now -5 is the new zero.",
"There is no absolute 0 or spatial reference point."
] | [
"Motion would be ill-defined in that situation on that scale too; if true, all it means is that two coordinates less than the Planck length apart are physically indistinguishable from one another, not that all possible locations for particles are separated by a Planck length.",
"It wouldn't be possible for all di... |
[
"How do astronauts stay grounded in space?"
] | [
false
] | Since low earth orbit is charged with plasma, what's keeping astronauts protected from a charge differential in their environment to keep them from getting electrocuted? | [
"Grounding is the just the act of bringing two things to the same reference potential. 0 volts isn't a universal thing. The space station is at a potential to the literal earth, but there is no way to transfer the charge. ",
"Afaik, there is no need. The space station is already keeping everything at the same pot... | [
"Actually, the ISS has a plasma contactor that is designed to prevent charge from building up on the station. It works as a small particle accelerator, firing charged particles away from the station. Ion thrusters have something similar; in addition to the main ion thrusters (accelerating positive ions) there of an... | [
"Interesting point, but this should have nothing to do with the astronauts. The space station may build up a charge to its surrounding environment, but the astronauts are inside. They are effectively grounded to the space station each time they touch it. They will not build up any significant charge relative to the... |
[
"Would a model helicopter function inside the ISS?"
] | [
false
] | I think that a small, collective pitch helicopter should be able to function in a presurized, 'zero gravity' enviroment. But I have a feeling that it might not be that simple. For one thing, the tail-rotor offsets the torque of the main rotor. On most helicopters, the main-rotor in turn counteracts the side-thrust of t... | [
"With extreme care it might be possible. When the main rotors operate it is going to take off in its ",
" direction. You could stop it with the remote control though and use the forward or back controls to pitch it over by 180 degrees, then fly it back to you. To turn 90 degrees use the yaw control to rotate arou... | [
"I was thinking of a model helicopter like the mcp-X, with collective pitch, cyclic, and an anti-torque tail rotor.",
"A fixed pitch helicopter is probably going to careen madly into a wall, because it can't slow down its climb, only speed it up.",
"A side question about a co-axial model though, If I could keep... | [
"Absolutely. Don't turn it on, and let it go. Then you have to blow on it to steer it. No, really, if you throttle up the rotors the toy would immediately sail up the main rotor axis. You need a means to control all 6 degrees of freedom, and a helicopter, in the wild, considers gravity immensely."
] |
[
"Will you absorb information if you play books on tape (e.g. Spanish, biology) while you sleep?"
] | [
false
] | [deleted] | [
"None. This was pretty well debunked in 1956, one group had 10 words played into their ears while they slept. The experimental group did not perform better than the control group when subsequently asked to identify the 10 words out of a list of 50."
] | [
"To my knowledge, no. It's a long-considered pop culture trope but I'm unaware of any current research into it. From a theoretical standpoint it doesn't make a lot of sense. Typically, one learns those items best on which one concentrates and focuses the most, all other things being equal. The sleep state (which in... | [
"I concur. There are no legitimate studies (this century, at least) that say it works."
] |
[
"Do the receptors for smell and taste have a short life span to prevent sensory adaptation (getting used to a taste/smell) ?"
] | [
false
] | null | [
"No and we do adapt to both tastes and smells"
] | [
"Do you have anything to support this? I haven't been able to find much online"
] | [
"If you go to google scholar and search for either taste or odor adaptation, you will find hundreds of articles on the topic"
] |
[
"How does tilting a glass slightly reduce froth?"
] | [
false
] | null | [
"Pouring beer vertically into a deep glass of beer creates extreme turbulence, which causes more gas to come out of solution, which increases froth.",
"Beer poured against the side of a tilted glass experiences more laminar flow (less turbulence)."
] | [
"It's not much about the distance, but yes, the glass catches the stream and lets it slide down in a straight line, whereas if the stream hits the middle of the beer it causes a messy churn (turbulence)."
] | [
"So basically because the liquid has to travel a shorter distance and the surface is at an angle it basically \"catches\" the beer and reduces the fizz? "
] |
[
"What causes spatial orbits in higher dimensions to be unstable? Is it linked to how gravity behaves or does it apply to any kind of orbit?"
] | [
false
] | Also, does this affect the existence of String Theory's higher dimensions? | [
"There are two parts to the proof. First consider a general force of the form F = k d",
" where k is a constant, d is a distance, and a is an exponent. You can show that closed stable orbits are only possible if a = 1 or -2. This law is Bertrand's theorem.",
"Now we must consider how gravity behaves in higher d... | [
"Bertrand's theorem applies to any central force which includes the electrostatic force and gravity. There is a strong connection between Gauss's law of electrostatics and the vector calculus law. "
] | [
"You can show that closed stable orbits are only possible if a = 1 or -2. This law is Bertrand's theorem.",
"Note that you have stable orbits for values of a in between as well - they are not closed, but a perihelion shift every orbit wouldn't be an issue. In General Relativity our orbits aren't perfectly closed ... |
[
"What makes us see \"white\"?"
] | [
false
] | White is obviously not a color on the spectrum of light, but rather it's what we get when you combine a few different wavelengths of light together. If you do the simple prism experiment you can see how white light is made up of the full rainbow... But then I also understand that we don't necessarily need EVERY color t... | [
"When all three colors of cones are excited equally, you see that as white. If you added some extra red light, you would see it as light red. If you then added extra green and blue to balance it out, it would excite all the cones equally again, and it would look like brighter white. If you added more light at the r... | [
"KSFT has a good answer so I'll just add a bit.",
"Also I'll add the eye ",
"absorbance spectrum",
" for clarification. (the dotted line is our rod cells)",
"If I have white light from rgb pixels and then I add in some yellow light, why wouldn't the yellow just blend in to the light?",
"I'm not sure what ... | [
"Okay, let me use some wavelength numbers, in nm...",
"Our cones are centered on 420, 534, and 564. If I take three sufficiently small light sources (so that I can't resolve the colors separately) which produce these exact wavelengths then I should see a point of white light, right? Assuming that they all have th... |
[
"Why doesn't drinking cold water cause us to lose weight?"
] | [
false
] | Hey ! This is how I think about this question. We increase weight if more energy goes into our body than goes out. We lose weight if the input is less than the output. When we pee our urine is at (or close to) body temperature lets be conservative and say 31C (87.8F). If we consume a litre of water at 1C (33.8F) there ... | [
"Heating 1 liter 30C uses about 30,000 calories of energy.",
"Which is equivalent to 30 Calories, as used to measure energy content of food. Considering that your average person consumes more than 2000 Calories a day, drinking cold water is not a good way to lose weight."
] | [
"There are 1000 (lower case c) calories in one (upper case c) Calorie aka food calorie.",
"Here's another way of looking at it: say you're an 80kg male, which means you're approximately 48L water, and assume you're in a 25C room and your internal temperature is 37C. In other words your body is a burner that keep... | [
"We use kilocalories in europe."
] |
[
"So how bad is the Fukushima thing really?"
] | [
false
] | It seems like all the discourse on it is either in the extremes of "OH MY GOD THIS IS THE WORST CATASTROPHE TO VISIT MANKIND." or "It's not really that bad and the situation is all under control. Here, eat this totally non radioactive complimentary sushi!" Personally I suspect that the truth lies somewhere in between t... | [
"Locally, for the immediate vicinity of the plant, very bad. For everybody living more than a few kilometers from the plant, practically irrelevant. ",
"This is like the Three Mile Island accident. There was a partial meltdown. Some radioactive material leaked in the environment. Probably very short lived isotope... | [
"Quantifying \"how bad\" something is, is more of a political argument than a scientific one. Better questions to ask are \"What levels of radiation are seen in seawater at 1mi, 10mi, 100 mi radii?\" or similar questions for ground, agricultural samples."
] | [
"I take issue with the last part of your post. There is a lot of background radiation such as cosmic rays and potassium-40. The total amount of nuclear material released (into the ocean) is ~11,111 times below the amount of 40K in the ocean. Once it spreads out for example gets into the atmosphere and then ocean (t... |
[
"How do those old-timey underwater naval mines even work?"
] | [
false
] | How do those even work? I understand that the mines detonate when a ship bumps into them, but how did the mines resist corrosion and still function? Why were probes placed under the mine even though the ships were likely to travel above the mine? | [
"Key point to be made here about the operation of the \"Hertz horn\" detonators -- They didn't have any \"moving parts\" so to speak. \"Ticking\" sea mines are a Hollywood embellishment, like land mines that don't detonate until you take your foot off them, or hand grenades with a ten-second fuse.",
"They were m... | [
"The mines resisted corrosion by being made with very thick metal and were painted. ",
"They had detonation horns all around them so there would be a chance they would be pulled up against the side of the ship even if a mine chain cutter was able to free them, or if a submarine passes under them. ",
"Also if th... | [
"The Dutch navy clears about 100 mines and bombs each year in the North sea, both from WW2 and from WW1."
] |
[
"Radon could be in the apartment I am thinking about renting out with friends. Am I in danger if it states the following?"
] | [
false
] | null | [
"That looks like the standard radon warning you'll find. Some states require that statement on rental contracts. It is pretty standard, but if you're still concerned get in contact with the ",
"Georgia Department of Community Affairs",
". They can also sell you ",
"radon detection tests",
"."
] | [
"I believe there are also electronic radon detectors which work much like smoke detectors. It is a good idea to keep yourself protected."
] | [
"Additionally, it's worth noting that most ",
"radon mitigation approaches",
" basically consist of creating adequate ventilation to the area."
] |
[
"Do rising temperatures (air or ocean) have an effect of plate tectonics?"
] | [
false
] | null | [
"In theory, it would have a ",
" effect, but really nothing noticeable. Between warmer oceans being more acidic (as CO2 forms carbonic acid) and, well, warmer the oceanic crust will be thinner. As such destructive plate boundaries will cause more subduction. Similarly, conservative and convergent boundaries will ... | [
"Thanks very much."
] | [
"Just spit balling, I'm a soft rock guy, But couldn't isostasy from glacial melt affect plate interactions?"
] |
[
"What supplements should I take daily to improve my overall health?"
] | [
false
] | [deleted] | [
"Vitamin D."
] | [
"Just be careful with how much you take! (",
"you may overdose",
")"
] | [
"As VicPaquettesCousin said, it really does depend on your current health. I got a general idea by tracking everything I ate for about a month. I used the free version of fitday.com but I'm sure there are multiple similar sites. By entering the food and quantities I ate, I could look at a chart of all of the vitami... |
[
"Does the temperature change from summer to fall happen faster than spring to summer?"
] | [
false
] | Given the start/finish of each season are separated by 3 month increments like Spring: 3/1 Summer: 6/1 Fall: 9/1 Winter: 12/1 Is there a noticeable difference which we would say “it got cold/hot all of a sudden”? | [
"I think this question is incomplete without naming a location on Earth. Even within the temperate zones, seasonality varies significantly place-to-place. ",
"Here's a website that gives monthly average highs and lows for different places in the US (which I'm guessing you're from by the month/date style in the qu... | [
"My mistake. The mid-Atlantic coast I mean. ",
"Thanks for the resource! I’ll dig into it. ",
"Is it plausible as a generalized statement that cold air fronts rush more quickly into warm regions than a warm front/heat wave? ",
"I noticed this when opening my freezer while the oven was on and heating the kitch... | [
"It's true that cold fronts generally move faster than warm fronts, but that's a very different process from seasonal warming/cooling. The processes that drive weather are very complex and look pretty different depending on the time scale you're looking at--for example, seasonal cycles vs \"synoptic\" scale feature... |
[
"How do we know where our limbs are?"
] | [
false
] | null | [
"Proprioception"
] | [
"To elaborate a little:",
"Stretch receptors, position and balance receptors in the inner ear, and assorted other ",
"\"proprioreceptors\"",
" send signals to our brains letting us know how our muscles are moving and where they are in space. When manipulating objects/space via hand-eye coordination, your ",
... | [
"As was posted, the answer is a sense called \"proprioception.\" There are nerve fibers in our tendons (Golgi tendon organ) and muscles (muscle spindles) that detect the position of a joint and the level of muscle contraction and send feedback to the cerebellum and cerebrum along several specific neural pathways, i... |
[
"Why do slugs come up onto dry porches/decks en masse at night?"
] | [
false
] | I'm really confused. So this comes from a problem I had to solve a few weeks ago, and although successful, it's still stuck in my craw because to me, as of now, it's a problem with no obvious source and seems contradictory to me. As I understand them, slugs are highly dependent on remaining in a moist environment and ... | [
"They’re climbing to find a mate. All slug species (as far as I know) need to suspend themselves from a line of mucus in order to mate. This is usually done in trees or bushes, but they’ll climb any vertical surface as they aren’t the smartest of creatures. Here’s a somewhat disturbing video on slug sex:",
"ht... | [
"omg THANK YOU this has been driving me crazy!!"
] | [
"That's an interesting idea not all slugs use the mucus line most don't. But I don't know why they come out on decks mating could be part of it. I thought they were looking for a new food sources not the deck itself but a tasty plant on the deck or on the other side of the deck. But like I said I really don't know.... |
[
"I'm trying to understand the Termination shock and heliosphere."
] | [
false
] | I have spent the last few hours researching the subject and exploring the subject based on the IBEX project and the voyagers 1 and 2. So far my understanding is that the termination shock is a sphere surrounding our solar-system created by the solar winds of the sun. It protects us from the cosmic radiation of distant ... | [
"The heliosphere is all the space in which the solar wind is the dominant \"wind\". Outside the heliosphere, the interstellar winds are the dominant \"wind\".",
"The heliopause is the point where the solar wind and the interstellar winds cancel eachother out. That is, it is the boundary between inside the heliosp... | [
"Thank you this helps alot. So are these interstellar winds made up of cosmic rays? Or what exactly are they? I know that they move uniformly from the center of the galaxy but what is at the center that creates them?"
] | [
"Cosmic rays are (usually) ",
" energetic particles that are ejected by supernova.",
"The solar and interstellar winds are (usually) just moderately energetic particles that are ejected by stars."
] |
[
"How can you prove, without using any scientific equipment, that the Earth rotates around the Sun?"
] | [
false
] | [deleted] | [
"It's the ",
" model that explains the retrograde motion. For example, there's the ",
"Ptolemaic model"
] | [
"It's the only model that explains the observed retrograde motion of the other planets in the sky. ",
"edit: In his book \"Death By Black Hole\" Neil Degrasse Tyson discusses all the things you can learn about astronomy by simply shoving a stick into the ground and watching the shadows. You might find that intere... | [
"It cannot be proven without a telescope, at least.",
"The only stimulus humans perceive coming from these celestial objects are visual - through indistinguishable white light and it's movement across the sky. So, without any instrumentation, a model that explains our visual observations is sufficient and, conseq... |
[
"Have any major scientific breakthroughs been produced both by accident and as a result of unethical development?"
] | [
false
] | null | [
"Would the ",
"Stanford Prison Experiment",
" count? The experiment probably would never have been approved if any oversight board was asked, and it definitely produced experiments that were unexpected.",
"LSD's effects were discovered accidentally, and Dr. Hoffman continued experimenting with it and document... | [
"Which kinda brings upon the question: Is Henrietta still considered as live being?"
] | [
"The Stanford Prison experiment might not be exactly what I was looking for, since the experiment itself was done purposely. But the Henrietta lacks link is very intriguing and matches what I was looking for. Thanks!"
] |
[
"Why is ethanol and not isopropanol used for hand sanitizer?"
] | [
false
] | There's news going on about kids drinking hand sanitizer to get drunk. Some kids still drink rubbing alcohol, but I guess to a lesser extent. Is rubbing alcohol not able to keep in a gel? | [
"I suspect it's as simple as ethanol being cheaper. (and more volatile) ",
"I's denaturated and therefore (almost) undrinkable. If people want to try to drink denatured ethanol, there are other and cheaper sources of it. It'd say the problem lies with people foolish enough to try to drink denatured alcohol, rathe... | [
"The only really significant difference I can think of right now is that Isopropanol is labelled as irritating (causing skin problems. It does, I know from personal experience :-( ), while ethanol is not.",
"Wikipedia seems to confirm that Isopropanol causes serious skin irritations (mostly on mucosa skin), and b... | [
"interesting, in labs, in order to sanitize a work surface before any bacterial plating can be done, ethanol is diluted to 70% just for the purpose to avoid it from becoming too volatile. this is because 90% ethanol is tool volatile to have any time to kill bacteria. as such i think volatility is not one of the rea... |
[
"Do biomass and liquid water contribute to earths gravity, and if so, how much gravity do they account for?"
] | [
false
] | It would seem to me that considering how much global biomass and water there is, that it must account for something. I also feel that since matter can't be created or destroyed, that It didn't add any gravity to the earth since formation, but how would gravity change though if we were theoretically able to remove it al... | [
"Wiki",
" cites the total nonbacterial biomass on Earth at 560e9 tonnes, while the mass of the earth is approximately ",
"6e24kg",
", or (since 1 tonne = 1000kg), 6e21 tonnes. The difference is an order of 10",
" . So that does not contribute very much. ",
"The ",
"USGS",
" lists the total volume o... | [
"I also feel that since matter can't be created or destroyed, that It didn't add any gravity to the earth since formation",
"That is correct, the biomass of Earth would have just been the regular mass of earth were there no life. To put it another way, when an animal is born the mass of the Earth does not increas... | [
"Yes, they do. Every bit of mass contributes to gravity, but it's very, very, very insignificant. The earth is nearly 13,000km from pole-to-pole, and the crust (which weighs significantly more than all water and biomass combined), is only 60km deep. That's .46%. So while the effects earth's biomass and water have o... |
[
"How come nobody talks about the hole in the ozone layer anymore?"
] | [
false
] | [deleted] | [
"It's still ",
"here.",
"It's not growing any more, but it'll take a loooong time to totally recover. We had a colloquium at our university, and it from that graph it looked like the ozone levels are just slightly recovering, but it's kinda too early to tell. From the graph I linked above, a recovery is not cle... | [
"I'd dispute this. There was a big push in the 90's not to report the widening hole per-se, but to educate the population about the cause, extent and dangers related to the depletion of the ozone layer. This caused the same \"scientists/environmentalists/activists don't know what they're talking about\" outcry we'r... | [
"In the words of Douglas Adams:",
"\"Listen, Murray, I called to ask you something.\"",
"\"I have a lot to do.\"",
"\"I just wanted to find out something about the dolphins.\"",
"\"No story. Last year's news. Forget 'em. They're gone.\"",
"\"It's important.\"",
"\"Listen, no one will touch it. You can't... |
[
"How are insane temperatures in fusion reactors measured?"
] | [
false
] | There was a headline recently that china had cracked a fusion heat record and produced a plasma three times hotter than the sun. How are these temperatures measured? Wouldn't any device that could do it be destroyed? Is it just like an assumption that is made based on how much energy is put into the system? How do they... | [
"Mainly, with very powerful lasers. As you say, any instrument which measured the temperature by being in contact with the plasma would (a) quickly be destroyed, and (b) quickly cool down and ruin the plasma itself in the process, so we have to measure the temperature by \"remote sensing\" methods with don't requir... | [
"Thank you very much for this detailed answer!"
] | [
"Hot plasmas like this don't emit black body radiation in the way \"normal\" things do. To emit a black body spectrum representative of its temperature, the plasma would have to be \"optically thick\" - meaning the particles making up the plasma would have to be interacting with the light (absorbing & re-emitting, ... |
[
"How many generations does it takes before medical history becomes irrelevant?"
] | [
false
] | null | [
"In theory, infinitely many. Consider for example a man that lived, say 30,000 years ago that had some recessive genetic disorder. He could pass this gene on for 1000 generations, and assuming no one else in the tree carried that gene, none of his descendents would developed this disease. Until after 1000 generatio... | [
"While this is technically true, I will mention to OP that typically when we take medical history, we usually ask for 2nd degree relatives (so up to grandparents, including aunts and uncles) and we will ask about siblings and children as well if pertinent. What we find is many patients don't have a great memory or ... | [
"I can't imagine that anything more than 3-4 generations would be beneficial. Not because you wouldn't benefit from information about your great-great-great grandfather's heart attack, but simply because a diagnosis from the early 1900s would likely be incorrect or only vaguely correct. Pre ",
"William Osler",
... |
[
"At which size do particles start casting shadows instead of behaving according to the Fraunhofer diffraction?"
] | [
false
] | We just learnt about Rayleigh, Mie and Fraunhofer and neither our Prof nor his contacts could sufficiently answer at which particle size the particle becomes too large for Fraunhofer diffraction and instead casts a shadow, like a regular ball for example. | [
"Diffraction happens at the edge of an object, regardless of it's size. However, the distance at which the pattern resolves is proportional to the size.",
"For example: at the right light frequency, the moon casts a diffraction pattern on the Earth."
] | [
"What you are asking for is called the Fresnel number F=r",
" / 2zw, where r=radius of the object, z is the distance from the object to the wall or whatever is behind the object and w the wavelength.",
"For F>>1 you get shadows and for F<<1 you get fraunhoffer diffraction. F~1 is known as the Fresnel region."
] | [
"You need to compare the coherence length of your light beam to the path difference of interfering beams. The coherence length tells you at which distance from your position the electric field is still the expected sinusoidal wave, and not part of a different wave pattern. The coherence length is on the order of a ... |
[
"Probably a simple physics question"
] | [
false
] | Say you drop something from x height and it takes y time to hit the ground. What do you have to do to x to double y? Ignore air resistance and friction and assume starting velocity is 0 and all that jazz. | [
"Starting from rest, the acceleration is g so the equation of motion for the height h from the ground is h(t) = x - 1/2 gt",
" . It hits the ground when h=0 so you have x=1/2 gt",
" which in your notation is x=1/2 gy",
" , so to double y, you need to multiply x by 4."
] | [
"Assuming something accelerates in a linear way . the item will keep accelerating. so its covering a greater distance each second as time goes on. so to double the time you have to quadruple the distance the item needs to travel. ",
"If you plot velocity against time on a graph, the area under the line represents... | [
"Here you go"
] |
[
"How is DNA converted into information that computers can interpret?"
] | [
false
] | When genetic samples taken from saliva for example are genotyped how is this done? How is DNA fed into a computer in a way that it can actually interpret as seen with services such as 23andMe? Spit -> X -> Digital representation of DNA, what is "X"? | [
"Fancy chemistry.",
"There are various technologies, but a very popular one is called sequencing by synthesis. This sequencing method relies on taking a series of photos of lighted spots where each spot is a short strand of DNA and the color of the lighted spot corresponds to a specific DNA letter (eg a is red, c... | [
"Good question! It's useful here to distinguish between ",
" and ",
".",
"To sequence DNA is to read it, as in going through it letter by letter and writing down the entire sequence of text. (Each \"letter\" in DNA is one of four chemical subcomponents called nitrogenous bases; we call them A, G, C and T.) Th... | [
"DNA has the brilliant ability to copy itself through 'base pairing'. In the language of molecular biologists - A pairs with T and G pairs with C. The Sequencing by Synthesis that Sox mentions makes use of this property. The X is adding chemistry in a specific order or with each of the A,T,G and C labeled with a ... |
[
"Is there any solid scientific evidence that facial microexpressions can reveal deception or dissemblance?"
] | [
false
] | Clearly there's good science behind the social psychology of human facial expressions: they consistently convey the same emotions across cultures, etc. But I'm REALLY skeptical when a psychologist pronounces, "This subject snarled his lip slightly for 325 milliseconds. He is therefore secretly angry, and lying about h... | [
"This is my area of focus in research. On my phone currently, and will try to write more later.",
"Generally, though, the answer is absolutely not. Microexpressions, along with a lot of ekmans other work, is not so much taken seriously anymore in legal psychology literature.",
"Edit: Sorry I'm being slow - I ha... | [
"This is related to the study of so-called \"Truth Wizards\" (",
"http://en.wikipedia.org/wiki/Wizards_Project",
"), a small proportion of people (0.25%) who seem to be significantly above average at detecting microexpressions and discerning truth from it (indeed, the TV Show \"Lie to Me\" is based off of this)... | [
"While TED Talks are interesting, I honestly think they are too shallow to offer more than a bit of entertainment."
] |
[
"In the many-world interpretation of quantum mechanics, how many worlds are there? (a) finite (b) countably infinite (c) uncountably infinite (d) all of a, b, or c lead to a contradiction?"
] | [
false
] | For reference: It appears there is an answer here (10 ... so that seems to be answer (a). Does anyone disagree or want to clarify? Does (a) imply a contradiction that isn't mentioned in that article? | [
"the number of worlds is fuzzy because the concept of a world having split and the two versions having decohered is fuzzy. The decoherence between two worlds develops over a finite, though very small, time, and is not a discrete event. The branching happens when coherence between the two sectors of the wavefunction... | [
"There are as many worlds as there are possible outcomes. Think of it as legitimizing possibility into something real, similar to a spatial dimension, like you can with time. How many moments were in your life? How many positions have you occupied? If you want to break everything into Planck units, that is the ... | [
"It honestly makes me sad that people take the infinite-worlds interpretation seriously, because it is utterly unverifiable pseudo-philosophy.",
"But, if we're going to delve into speculation, we might as well do it right. If my understanding of the theory is correct, then every quantum-mechanical 'event' (Equiva... |
[
"Where is all the water in humans?"
] | [
false
] | For being ~70% water, it doesn't really seem that abundant. I assume it's just mixed in all over the place, but is there one specific place where it is most prevalent? Blood? Stomach acid? It just doesn't seem like it really takes up that much of our body. | [
"Water is inside ",
". It's in your blood. Bone marrow. Organs. It's everywhere.",
"In general, chemical reactions have to be done in a solvent. Water is the body's solvent."
] | [
"Not only are your cells mostly full of water, as others have mentioned, but also the spaces in between your cells (the extracellular matrix) are mostly water as well. ",
"It's easier to list the parts of your body that AREN'T mostly water than to the list the ones that are:",
"stratum corneum (the topmost laye... | [
"Jello's 84.2% water (2 cups hot water + 2 cups cold water = 32 oz water, to 6 oz Jello powder). I assume it's something like that."
] |
[
"What would happen if a single atom of, let's say carbon, hit you at (1/2)c?"
] | [
false
] | This question was inspired by a question from a few weeks ago about a tic tac at (1/100)c. I want to know if it would vaporize you or just punch a very small hole out of you. | [
"Based on ",
"this calculator",
" a helium nucleus (didn't find one for carbon) at 580 MeV (your 0.5c) would go through about 15cm of muscle matter before stopping. It would wreak all kind of havoc at the cellular level, causing some cells along its path to die. Note that the largest energy transfer density wou... | [
"For all the times I have seen discussion along the lines of \"what would happen if you stuck your hand into the beam of a particle accelerator\", this is the first I have actually seen mention of Anatoli Bugorski, despite it being an example of damn nearly that exact thing happening."
] | [
"For all the times I have seen discussion along the lines of \"what would happen if you stuck your hand into the beam of a particle accelerator\", this is the first I have actually seen mention of Anatoli Bugorski, despite it being an example of damn nearly that exact thing happening."
] |
[
"A few questions about fMRI..."
] | [
false
] | Almost every neuroscience-related article or study that's published nowadays contains data gathered through the use of fMRI (functional Magnetic Resonance Imaging). I have a vague idea of what this technique measures (increases in blood flow to various brain regions?), but I was wondering if someone could provide a mor... | [
"I wish I had more time to answer, but I feel I should at least send you a great ",
"review",
" article on the topic. fMRI uses blood-oxygen level dependent signals (BOLD) which is a surrogate measure of neuronal activity. Generally the idea is that increased cellular activity is matched with an increased metab... | [
"An fMRI machine is an MRI programmed differently. A typical MRI machine will examine the hydrogen atoms which provide a relatively strong signal due to their quantity and shielding (consider developing a pulse sequence to increase contrast between water, fat, and protein). In fMRI you look at oxygenated hemoglobin... | [
"I have a vague idea of what this technique measures (increases in blood flow to various brain regions?), but I was wondering if someone could provide a more in-depth description.",
"The source of the fMRI signal being measured is vascular, i.e. changes in the blood oxygenation, flow and volume. The signal itsel... |
[
"How do we detect when neutrinos collide into matter if they are electrically neutral? Isn't what we think of as a collision just an electromagnetic interaction?"
] | [
false
] | Or does it have to do with the weak force? I've taken a few courses on QM so don't hold back! | [
"Your intuition is correct. What we usually think of as a collision is due to the electromagnetic interaction, so neutrinos do not participate. However, neutrinos interact through the weak interaction, and so can \"collide\" in that sense. The fact that the weak interaction is so much weaker than the electromagneti... | [
"The basic interactions that can occur are that the neutrino can exchange a W boson with a neutron, which results in the neutrino and neutron turning into an electron and a proton, or the neutrino can exchange a Z boson with an electron (or a W boson as well in the case of electron neutrinos) which causes them to s... | [
"What specifically is going on in the collision? is the neutrino getting close enough to another weakly-interacting particle that they exchange virtual bosons? Is this only rare because the weak force is short ranged?"
] |
[
"How is heat distributed in the deep ocean compared to shallower parts?"
] | [
false
] | I’m not sure how accurate this is, but I remember learning somewhere deep sea creatures would be the first to cause a major food chain disruption due to global warming and the rise in water temps. However, I was researching the coral reefs and saw the raise in water temp is partly why they’re dying. So— do the typical ... | [
"The deep sea is extremely cold with the exception of hydrothermal vents that are extremely hot and house extremophilic microorganisms.",
"In general, there are no uniform ocean temperature changes. Loss in ocean biodiversity I believe is more related to ocean acidification (due to more carbon absorption from the... | [
"It takes a while for the warming signal to propagate to the deep ocean and it is absorbing heat and warming slower than the surface ocean. With that said, ocean temperature measurements become somewhat sparse below about 2000 metres. See ",
"this article at the Oceanography Society",
" for a summary with some ... | [
"That article is perfect, thank you!! Interesting that the southern hem deep sea is warming significantly faster… no wonder some americans don’t believe in global warming 🥵"
] |
[
"Why hasn't neuroimaging been used much by scientists to debunk paranormal claims pertaining to the brain?"
] | [
false
] | null | [
"Hm. Ok, so the general, practical answer here is that fMRI is very expensive and to get funding to do a study to disprove something that a majority of scientists do no believe is possible is a tough sell for a granting agency. ",
"From a publishing standpoint, it's also difficult to publish something along the l... | [
"Like what kind of claims?"
] | [
"Hypnosis retrieving past life memories. Psychics using some unknown part of their brains to scan someone's aura. Mediums doing the same to talk to the dead."
] |
[
"Lay question regarding free will/probability"
] | [
false
] | null | [
"I personally believe in free-will being an illusion. I used to love thinking about this sort of thing. I thought up the \"free-will is an illusion\", the swampman thought experiment, and the theory of heat-death before I knew any of them were actually well established theories with a lot written about each.",
"T... | [
"I agree, but I'm not interested in a purely philosophical viewpoint. I guess I'd just really like to understand how quantum mechanics nullifies certain things that are so intuitive about the macro world. How could things that happened have had any less than a 100% probability of happening?"
] | [
"Ahh, well as far as the actual science goes I'll have to take my leave as I know nothing pertaining to that. Just for fun, ",
"heres a clip",
" from the movie Waking Life on the subject. Neat movie, worth a watch."
] |
[
"Is it possible for a virus or bacteria to target only a specific ethnicity? I know there are genetic predispositions for ailments like sickle cell-- but are there any contagious diseases that show a strong bias towards genetic traits that are strongly associated with ethnicity?"
] | [
false
] | null | [
"http://www.bbc.co.uk/news/science-environment-14673047"
] | [
"You will have to define \"strong bias\" very clearly. AFAIK there is no disease that predominantly affects only people of a certain ethnicity/race, simply because we humans all ",
" extremely similar to each other. Sure there are differences but they are not big enough that a disease causing pathogen cannot jump... | [
"Not 100% sure, but I'd go so far as to say: \"No.\"",
"For specificity viruses and bacteria need receptors/targets to attack and I've never heard of a racial difference in cellular protein make up in average people. You can cite predispositions of particular groups towards certain mutations (e.g. sickle cell, ∆c... |
[
"Is there a benefit to getting upset or offended with someone?"
] | [
false
] | null | [
"If you didn't get upset when bad things happened you wouldn't take steps to preventing bad things from happening."
] | [
"isn't it possible to take rational steps to fix issues without getting emotional?"
] | [
"Lets other people know you don't like what they're doing. In the future, they might change that."
] |
[
"How do people go about Optimizing a complex system where each variable affects affects another?"
] | [
false
] | For example, I am currently modeling a train powered compressed air. i've deduced optimizing the tank size will result in the most change, but changing volume/gas will then affect the mass and area, which will then affect your normal force and your drag force. Seems like everything is intertwined. I'm sure there are so... | [
"Well, that's the problem, isn't it! Optimization is an enormous subject with tons of literature from the classical to the very modern.",
"To learn more general info, you can look up texts on mathematical optimization, control theory, and partial differential equations. Again, there are countless textbooks for a... | [
"I didn't necessarily have a particular question, more on common practices to go about optimization for the sake of knowledge. For a class in college, we were to mathematically simulate a train in matlab and then optimize to find the best model train to race a 10 m track. This included run time and fill time of a c... | [
"What are you trying to optimize (speed?, distance? etc...) for and how far have you gotten? How much calculus do you know? The analytic way would be the calculus of variations. It is similar to how one can find the min/max of a function by looking for where the derivative is zero, only applied to, as you say, syst... |
[
"Is there such thing as a symbiotic virus?"
] | [
false
] | Is there viruses that have similar symbiotic relationships with animals to the relationship between some bacteria and animals? | [
"Any environment with lots of bacteria (including us) will be chock full of phage. A recent paper came out in PNAS that showed that some phage bind to mucus produced by cells and can protect them from bacterial infection. They argue that phage can be an important part of immunity against bacteria -however, the stud... | [
"You might be interested in bacteriophages! These are viruses that infect bacteria. There's been research on how to use them to our advantage in order to fight bacterial infections.",
"However, since viruses are pathogens that are not considered to be life forms by all, \"sybiotic\" might not be the right word."
... | [
"Are there natural bacteriophages that can survive in a host long term and protect it from certain bacteria? "
] |
[
"How much of the original zygotal DNA remains into Adult hood, and does it end up in the same place in everyone?"
] | [
false
] | null | [
"Hi hawaiicouchguy thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the ... | [
"Biology"
] | [
"'Biology'"
] |
[
"If hot air rises and cold air sinks, why does it get colder as you increase in elevation?"
] | [
false
] | null | [
"All the answers here so far are incorrect on a fundamental level, because they all neglect one important fact: temperature doesn't always decrease with height. In our stratosphere and thermosphere, temperature ",
" with height.",
"For all planetary atmospheres in our solar system, there's heating from below as... | [
"Its rather interesting to note that within regions such as the thermosphere the temperature can rise up to 2000°C during the day and is subject to solar activity. However a thermometer would indicate a value well below 0°C primarily because the energy loss due to thermal radiation would far exceed that acquired by... | [
"How do you measure the temperature in a situation like that where a standard thermometer clearly doesn't work?"
] |
[
"What happens when a charged black hole evaporates?"
] | [
false
] | [deleted] | [
"Hawking evaporation is not limited to photons. If a black hole's temperature becomes of order the rest mass of an electron, the black hole can radiate electrons as well, which can carry away the black hole's charge. ",
"More realistically, however, a highly charged black hole would attract and swallow particle... | [
"In theoretical physics you often use ",
"Natural Units",
"With the Boltzman constant and the speed of light set to 1 (dismensionless), mass, energy and temperature have the same dimension : mc",
" is the rest energy and the thermal energy is k_B*T (times some dimensionless constant)"
] | [
"If a black hole's temperature becomes of order the rest mass of an electron",
"In what units would you make that comparison? I don't immediately see how you'd relate Kelvins to grams. "
] |
[
"If we were eradicate mosquitoes from the earth, what effect would it have on the ecosystem?"
] | [
false
] | null | [
"This isn't an easy question to answer. Are you going to eliminate all mosquitoes or just those that bite humans? If you did eradicate them would you do it suddenly or would it take a long time? But since you ask here is some wild speculation based on a ",
"nature article",
" and me being an ecologist.",
"Bas... | [
"Mosquitoes are one of the worlds great success stories. It must be stressed that they participate to not one, but several different ecosystems.",
"I can tell you that for arctic (tundra) ecosystems, where there is very little biodiversity and the food chain is ultra short, you would deprive fish and birds of a k... | [
"I'm sorry, I have to speak up about this terribly written article. The author lists ",
" of evidence about why mosquitoes are important for the environment and then comes to the silly conclusion that they ",
" important? ",
"Many species of insect, spider, salamander, lizard and frog would also lose a primar... |
[
"Have we ever attempted to create a life form that is other than carbon based molecules? If so the probability of ETL is higher isn't it?"
] | [
false
] | null | [
"No, nobody's done that. What would such an attempt even entail? We don't really know of that many inorganic polymers, compared to ones containing carbon. ",
"I don't see how it'd really change anything regarding the probability of extraterrestrial life. Do we know of anywhere where other heavy elements exist but... | [
"Carbon might be locked up somehow, or silicon may be more available for other reasons. It would require more energy to make and break bonds (which is all life is) but it is possible to base life on somethign other than carbon."
] | [
"It would require more energy to make and break bonds ",
"Si-Si bonds are ",
" than carbon-carbon bonds, that's a large part of the problem. ",
"but it is possible to base life on somethign other than carbon.",
"Then explain your rationale and publish a paper on it. Because nobody else has come up with an a... |
[
"What is left behind when a black hole explodes?"
] | [
false
] | So through Hawking radiation, a black hole evaporates and eventually explodes. If it explodes, shouldn't that leave behind matter? Can there be an explosion without matter? Wouldn't this also mean that after the Stelliferous Era, there could be more fusion taking place as matter is left behind from black hole explosion... | [
"It's not known whether black hole evaporation leaves a remnant or not.",
"Black holes lose mass by Hawking radiation until they reach around the Planck mass (20 or so micrograms). Then, they're not black holes anymore as they've entered the quantum gravity regime. We don't know for sure what quantum gravity is o... | [
"That doesn't seem possible. A stationary zero mass state must be the vacuum.",
"Maybe they're talking about losing most of the mass to leave a naked singularity (without an event horizon) but this process is impossible in semiclassical general relativity. It could be only possible (maybe) in the quantum gravity ... | [
"Thanks for the reply!"
] |
[
"Why do laser pointers appear to have a noticeable trail when moved quickly across a surface?"
] | [
false
] | null | [
"The same reason why if somebody shines a bright light in your eye you will continue to see it after you close your eyes. Known as image burn-in or afterimage. A laser pointer spot is very bright and the trails are just the eye experiencing this burn in effect. There isn't actually a trail."
] | [
"I had a feeling it was that simple, but I was still curious. Thanks for the answer!"
] | [
"Same reason as you see objects being blurry; it's your eyes compensating to create fluidity with a something that is moving quickly.",
"It looks different because a laser is a pure wavelength light (relatively) which doesn't really occur naturally."
] |
[
"Difference between HIV and immunosuppressants for Autoimmune diseases?"
] | [
false
] | null | [
"The mechanisms of immunosuppression are different. HIV infects your immune cells and kills them off. Immunosuppressive agents block certain immune modulator molecules that then suppresses the immune response. Both, however, are immunosuppressed states and therefore patients with these conditions are at high risk o... | [
"Doesn't answer ops question. For HIV certain parts of your immune system are almost completely disabled. For immuno supressent drugs they are targeted and do not completely suppress the immune systems. Beyond that I don't know the specifics."
] | [
"Apologies, I was trying to be as simple about it as possible. I have no idea the level they are starting from and was hoping that they could draw their own conclusions from the info provided. If there are two different pathways that both prognoses result in immune alteration, does not mean one will \"cross out\" t... |
[
"Why is gene splicing not as effective in animals as in plants?"
] | [
false
] | Any information on this will be valued. | [
"So, I believe they are both similarly effective in terms of the results you’d get, but the consequent issues involved are generally more significant in animals than plants. ",
"The short answer, plants have far greater genomic plasticity than animals. Their genes change at a far greater rate than animals which h... | [
"Thank you, this is the kind of comment I was looking for.",
"So you are saying that because animals can migrate, their ability to take in foreign genes is lower than that of plants because plants need to adapt constantly but at the end of the day you can do the same with animals as with plants? So for example; T... | [
"Happy to help.",
"So, it’s not solely due to this difference in mobility that these differences in genome plasticity exist, another factor is mode of reproduction, for example. It’s an extremely long-winded and complex evolutionary process that’s lead to such different forms of life, so pinpointing exactly when ... |
[
"Why does the administration of a Beta Blocker not lead to runaway artery constriction?"
] | [
false
] | I'm in class and we're learning about Beta Blockers. Why does the administration of a beta blocker not lead to a feedback loop where the alpha receptors are continually activated by the baroreceptor reflex. What I mean is, why do the baroreceptors not continually sense a decreased BP and increase sympathetic tone conti... | [
"If you abruptly withdraw the beta blocker, you will see that. You also have to consider that people with hypertension already have activated the Angiotension pathway because the kidneys are seeing relatively less perfusion. that is also mitigating the effect of your beta blockers. "
] | [
"Why would cessation of a beta blocker lead to activation of the baroreceptor reflex such that it would cause activation of alpha receptors? Wouldn't it cause inhibition of alpha receptors leading to vasodilation since you are increasing BP? "
] | [
"I can think of two possibilities:",
"The atrial baroreceptors would not be activated if you artificially lower MAP to a ",
" level. For these receptors to fire, you probably need to drop MAP to an unhealthy level.",
"Adaptation of atrial baroreceptors prevents sustained reflex activity. So even if these ba... |
[
"What fluorescent dye should I use to make silicone oil fluoresce?"
] | [
false
] | Very specific question. Overly specific for ? Maybe but I need you right now reddit! I am conducting research in fluid mechanics. I have a two-phase flow consisting of silicone oil, and a water-glycerin solution. We need to dye only the oil with a fluorescing dye. Our laser is green and emits at 532nm. One that I found... | [
"The oil is by far the smaller of the two volume/mass fractions. The facility has about 25 gallons of fluid and the oil is a dispersed droplet phase. If we can get the oil to fluoresce, we can measure the droplet size distribution. This might be easier than trying to use an inverted image that would result from add... | [
"I suggest you contact tech support at ",
"Molecular Probes",
", to see if they can help. You may need to conjugate a fluorophore to something that can dissolve in the oil.",
"You might be able to use a surfactant, as well (which would partition to the water-oil interface.",
"Generally what size range are ... | [
"I've worked with Nile Red, and it's a pretty good dye. Be careful with it, as it's fluorescent properties are highly dependent on the solvent, so you really want to check ex/em in your oil. It also might have some fluorescence in the glycerol solution, depending on the glycerol concentration, but as far as I know ... |
[
"Why can really bad odors induce vomit?"
] | [
false
] | null | [
"So your brain is quietly monitoring your body and the environment around you for biological threats. By this I mean a bacterial or viral infection, ingesting something toxic etc. Sometimes the brain senses some putrid odors and interprets that as being near or ingesting something that obviously should not be eaten... | [
"We really got lucky that of the two expulsion methods we evolved to vomit in these instances."
] | [
"Some animals, (like horses) cannot vomit. If they get a stomach ache they just die unless walked enough to pass it out the other end."
] |
[
"Can Hodgkins lymphoma, or other lymphomas, be diagnosed through a routine blood test? As in when they are not looking for it/looking for something else?"
] | [
false
] | Thank you for any answers. | [
"You can't really diagnose Hodgkin's lymphoma or any other lymphomas using only routine blood tests such as RBC, WBC. These only show non-specific changes that could be attributed to hundreds of other diseases other than lymphomas. ",
"Being malignant, solid tumors of the lymph nodes, lymphomas require a biopsy a... | [
"Smudge cells on peripheral blood smear are pretty much diagnostic for CLL, as one example. In this paper (",
"http://www.ncbi.nlm.nih.gov/pubmed/17418074",
") they discuss how quantification of smudge cells actually provides a useful measure of patient prognosis."
] | [
"Reed-Sternberg cells have been seen in the peripheral blood, but it is exceedingly rare. You will often see very non-specific findings on other blood tests when diagnosing lymphoma. The common blood tests may raise a suspicion of lymphoma, but are very rarely diagnostic of it. One exception could be chronic lympho... |
[
"How do we know the pillars of life were destroyed 1,000 years ago if it is 7,000 light years away?"
] | [
false
] | How do we know it was destroyed if the light showing these images is still 6,000 light years away for reaching us? For reference: | [
"No, but a good question. In essence what the scientists are doing is modelling with a number of well made assumptions.",
"In essence, what you are describing is exactly what we do with weather forecasting. We have accumulated data for over 100 years on weather patterns and using modelling and based on the presen... | [
"Piggy-backing - Let's say an event like this occurs enough times that scientists can tell 6000 years ahead of time based on information already collected that the event has transpired, even if \"confirmation\" in the form of light would still take 1000 more light years to get to us. They'd be able to tell purely f... | [
"Piggy-backing - Let's say an event like this occurs enough times that scientists can tell 6000 years ahead of time based on information already collected that the event has transpired, even if \"confirmation\" in the form of light would still take 1000 more light years to get to us. They'd be able to tell purely f... |
[
"How comes the sand of most beaches is yellow and very few beaches have either white or black/gray sand? Aren't white/black/gray rocks way more common ?"
] | [
false
] | null | [
"Most beaches are made of one of two things: quartz or carbonate.",
"When you take those black/gray rocks and start eroding them and breaking them down, the quartz (which is nominally clear, but when in a big pile ends up being sort of yellow) is the last thing to survive that is sand-sized. Most of the darker mi... | [
"Black sand, such as on our beaches here in Hawaii - are broken down lava - usually from a'a clinkers or lava benches that have collapsed and broken apart - these are brand new flows that haven't aged much nor mixed with other rocks and sands (some beaches can be minutes old - but may not last more than days or wee... | [
"Sand often has large amounts of animal material in it, like seashells, calciferous algaes, corals and the waste of coral eating fish, which tend to be a lighter color. I believe quartz is also a common component, especially in extremely white beaches such as those found on the northern gulf coast of Florida."
] |
[
"Why are there exactly 7 full notes? (Music)"
] | [
false
] | Hey, why are there exactly 7 full notes in our music system and not maybe 9 or 15? Is it just coincidence or does it have a scientific reason? Thanks | [
"The most basic interval is an octave, which represents a doubling of frequency. The second most basic interval is a fifth, which is a ratio of 3:2, or a fourth, which is a ratio of 4:3. These are the perfect intervals, and all other intervals can be derived from them. The perfect intervals have been part of mus... | [
"Only in Western music (with a few exceptions) will you find a scale with seven distinct notes. The range of frequencies between octaves is scientifically determined, but our culture has made us recognize seven specific frequencies as pleasing when played in order. Other cultures have notes that are a little bit ... | [
"Most other cultures use the 5-note pentatonic scale - imagine if you only played the black keys on the piano."
] |
[
"Does hand sanitiser use make pathogens more hand sanitiser resistant, in the same way antibiotic use does?"
] | [
false
] | While absolutely necessary at the moment, seeing hand sanitiser everywhere had got me thinking. We have really overused antibiotics, creating a new problem for ourselves with antibiotic resistant pathogens, is there a chance we are in the process of doing the same with hand sanitisers? | [
"No. \nHand sanitizer uses alcohol to damage the lipid membrane of microorganisms. This is a very simple mechanism. It would be very difficult for infectious agents to get around this. ",
"In contrast antibiotics usually interfere with bacterial metabolism in a more complex manner such as inhibiting a particular ... | [
"Evolution of alcohol resistant bacteria is a concern, but there is not a lot of evidence out there that it will happen any time soon. ",
"Enteroccocus Faecium",
" is a focus of study in the evolution of bacterial alcohol resistance. 70% isopropanol seems to readily kill it, but more dilute solutions are less e... | [
"Other than viruses, some of which just have a protein coat, all living things have a bilayer lipid membrane. It is necessary for the ability to selectively transport things in and out of the cell, and saying it would be difficult to do things without one is a serious understatement.\nEvolving a non lipid membrane ... |
[
"Why does increasing nickel content in lithium-ion batteries increase the battery capacity?"
] | [
false
] | From what I understand, current research in lithium-ion batteries focuses heavily on improving the cathode electrode. Many research aims to increase the nickel content which increases the capacity of the battery, as "nickel is the main redox species in the host structure". (Source: ) However, I don't understand why n... | [
"No problem, I'm glad if it helped. ",
"As for this over ox/redox, the issue is related to other reactions that occur in those voltage ranges outside of normal operation (they also happen some during normal ranges). If those reactions didn't occur, we would likely charge to higher voltages and discharge to lowe... | [
"There is still some debate on the specifics and it is in part related to interactions with the other elements in the crystal structure. The effect acts on a specific layered structure, generally referred to as Li(M)O2, where M could be about any transition metal, but the best variants today combine 3 transition m... | [
"Also, for some basics on batteries... the normal nomenclature of batteries describes a battery that is ready to be discharged or actively being discharged. We reverse that when we recharge the cell. So with that said, when we discharge a battery, the cathode is reduced and the anode is oxidized. When we charge ... |
[
"What happens during hypnosis?"
] | [
false
] | null | [
"go into details, what happened to you, what to you recall "
] | [
"The question of what actually happens during hypnosis is still an open question in psychology. That said, there are hypotheses as to what happens when you're being hypnotised.",
"Generally speaking the hypotheses fall into two categories, the state and non-state models. A short summary of each would be that the ... | [
"I've removed your question as it's too personal. If you're curious about hypnosis, you can ",
"read some of the prior posts."
] |
[
"Is it possible to change the genetic information of an organism after Birth?"
] | [
false
] | Recently I read an article about the potential pros and cons of genetic manipulation in human beings. The article seemed to exclusively discuss manipulating the organism before it's actual birth by reprogramming dead viruses to change the existing DNA. My question is, could this process be done to a person who is alre... | [
"You are talking about an ideal world, but if we did correct the mutation in CF, then it would clear up the disease itself rather quickly. The major issue with CF is the recurrent infections you can get, but assuming those haven't done any lasting damage to your body (and assuming you weren't hit with any of the mo... | [
"In all actuality, our existing DNA changes upon each replication - enzymes aren't perfect so there is always going to be some base mutations during DNA synthesis. In theory, if a gene was changed in a person who was already \"born\" via gene therapy, as the new RNA/protein is synthesized it would start mediating c... | [
"The reason for this being you are talking about correcting the \"error\" in the DNA in each individual cell, correct? Couldn't we affect a large portion and allow the natural function of cell division take over from there to remodel over time? Perhaps this would best used with fast regenerating cells over longer l... |
[
"Hypothetical Space Travel: Antimatter and its mass or lack there of"
] | [
false
] | With the hypothetical antimatter driven space craft, would fuel be counted towards the over all mass of the space craft? I assume that an antimatter engine would be equal parts matter and antimatter, however, I do not understand how antimatter equates to mass. Would it cancel out the mass of the matter or does it still... | [
"Antimatter has positive mass, just like matter. 1 kg of matter and 1 kg of antimatter have a total mass of 2 kg."
] | [
"Well. That was simple. ",
"Do you have a source for this?"
] | [
"Matter that has funny mass is usually termed \"exotic matter.\" Purely theoretical for now."
] |
[
"How efficient is nuclear energy, once you factor in the cost to enrich uranium, build and operate the plant, and safely store the waste?"
] | [
false
] | [deleted] | [
"While technically true, in my opinion it's misleading to say it produces more fissile material than it consumes because that gives the impression that breeder reactors can operate forever by recycling the same fuel. Obviously that's false since it would allow you to build a perpetual motion machine.",
"It's per... | [
"Cost of fuel",
"Cost of the whole process versus coal",
"Fuel Cycle Information",
"Gen IV Reactor Info",
"NRC",
"Those answer your questions. It isn't a short answer or concise answer but that should answer about everything. From ground to dumpster, nuclear is by far cleaner and produces a ton less waste... | [
"It is worth making the distinction."
] |
[
"Why is it that when you stare into a light bulb you can shut your eyes and still see a glowing image of the light."
] | [
false
] | another good example of this is the reverse black and white images that when you stare at them, after thirty seconds if you look at a white wall the image reveals itself. | [
"The retinal photoreceptors are stimulated and likely continue to be stimulated after a bright light exposure. As long as they continue to be stimulated, a signal is sent to the brain that an light persists (positive afterimage). Eventually, it will fade as the stimulation decreases and may persist as a negative ... | [
"According to the wikipedia article you cite, what OP is referring to not because the photoreceptors continue to be stimulated. Rather, it is because they are no longer responsive temporarily after being stimulated strongly. This is responsible for producing a temporary afterimage after one stares into a strong l... | [
"After they've been exposed to a bright pattern for a while the light sensitive cells in your retina adapt, lose sensitivity and stop sending as strong a signal to your brain as they did initially. ",
"When you change your focus from the pattern to something uniform like a white wall, the adapted cells take a whi... |
[
"Medication - is there a difference between absorption in the mouth vs. stomach?"
] | [
false
] | I've read that in the event of early symptoms of angina one should put an aspirin under their tongue, as there will be some direct absorption into the veins there, delivering the blood thinner directly to the heart. I guess first of all - is this true? Secondly, if so - is there a difference between doing that and simp... | [
"I'm not so sure that just putting the aspirin under the tongue will do much in the first place for early symptoms of angina (dissolving the tablet itself is a problem if just in the mouth). If it's a true event, chewing the aspirin and swallowing allows for a faster antiplatelet effect. Time is tissue; preventin... | [
"Thank you for the thorough reply!"
] | [
"To experts who have come here to answer this question: If you have the time, please consider fact-checking and adding citations to ",
"http://en.wikipedia.org/wiki/Sublingual_administration",
"."
] |
[
"Why do we as humans cry out when in pain?"
] | [
false
] | Today I sprained my ankle. It was a very painful experience and was screaming. Ive hurt myself many times before, but this was one of the first times I ever really screamed out in agony. Was curious as to why we do this? | [
"Many species vocalize pain somehow. Coming from an adult, it's a warning for everyone else in the group that something nasty is going on, and they should be on the alert. Coming from a child, it's a cry for help."
] | [
"It seems like it would have to be because it warns others and can summon help. ",
"Being wounded AND drawing attention to yourself would seem to be a surefire way of getting eaten in the wild otherwise."
] | [
"It depends on what kind of injury you get or situation you are in whether you will screem or not. Anything involving adrenaline will dull pain so as to make it barely noticeable. In that case the pain signal is only there to make you aware of an injury while not drawing too much attention from what is happening. F... |
[
"AskScience AMA Series: We've discovered that pancreatic cancer is detectable based on microbes in stool, with the potential for earlier screening in the future. AUA!"
] | [
false
] | Hi Reddit! We are Ece Kartal ( ), Sebastian Schmidt ( ) and Esther Molina-Montes ( ). We are lead authors on a recently published study showing that non-invasive (and early) detection of pancreatic cancer may be possible using stool samples. Ask Us Anything! Pancreatic cancer is a horrible disease: although few people ... | [
"I did my PhD thesis on PDAC invasion and migration and I always like to ask the wild conjecture questions. Based on the discussion and your post here you clearly have a hunch that this microbial profile is not only predictive, but also contributory to the inflammatory processes that make PDAC so invasive and migra... | [
"Just the promise of being able to (soon???) detect this type of cancer before it is too late... incredible. Thank you all for your work. In the last month, I have learned that 2 acquaintances have been diagnosed with pancreatic cancer. One, an 82yo woman, is in the end stages after it advanced rapidly since dia... | [
"How do you get your findings actually implemented into health systems?"
] |
[
"Is this graphic still valid? I thought that the universe was always was infinite in size. Only the density has changed since the time of the big bang."
] | [
false
] | null | [
"It's mostly right. The numbers are all rounded off, and best estimates of the duration and severity of inflation are still coming into focus.",
"The ",
" error lies in the sentence that begins, \"The cosmos goes through…\" If we take \"cosmos\" to be a synonym here for \"universe\" — which is fine — then it's ... | [
"This quote:",
"expanding from the size of an atom to that of a grapefruit in a tiny fraction of a second",
"is what bothered me the most. If the cosmos was at one time the size of a grapefruit then there must be a center and an outer edge. Two things that ",
"/r/AskScience",
" have taught me aren't likely ... | [
"I see. Thanks that makes a lot of sense."
] |
[
"Why does snake venom turn blood into a gel?"
] | [
false
] | Why does snake venom interact with blood by turning it into a gel or solid of some sort? | [
"Some snake venoms have the ability to cause massive clots in your blood which is why it turns into a gel. The reason it can do this is because it activates your coagulation pathway in your blood somehow. There are a few mechanisms that can cause this. The snake venom could be an activator of prothrombin, fibrinoge... | [
"Does this cause immediate death? "
] | [
"Would depend on how strong an activator of the pathway it is and how much actually got into the bloodstream. Antivenom exists for most if not all snake bites the problem is getting it in time."
] |
[
"Layman questions about Relativity, Light Speed, and Time."
] | [
false
] | null | [
"yes",
"No (but kind of). You forgot length contraction (",
"http://en.wikipedia.org/wiki/Length_contraction",
"). Correct insofar as the light takes longer from (A) to (B) than (B) to (A). I don't know where the 1/10th of a year come from, because the light travels back with a relative speed (relative to (A)... | [
"1) That looks fine.",
"2) In John's reference frame, the distance between (A) and (B) is approximately 0.436 light-years. (B) is moving at 0.9c and the light is moving at c, so the distance between the light and (B) is decreasing at 0.1c, so it will take about 4.36 years for the light to reach (B). On the way ba... | [
"Say prior to introducing the X/John frame of reference, Bob ties a string from (A) to (B). This string is stretched taught at maximum length L. Now, introduce John's frame of reference on X, which is speeding away from Bob's frame of reference. To Bob, the string is still pulled taught. To John, the string would a... |
[
"Are the spacecraft on display at museums (shuttles, Apollo/Gemini capsules,) radioactive from their time in space?"
] | [
false
] | null | [
"No.",
"Being in space ",
" you, it doesn't make you ",
"."
] | [
"There are two separate things: RADIOACTIVE ELEMENTS (heavy nuclei) and RADIATION (light nuclei or electromagnetic waves, e.g. x-rays).",
"Huge amounts of RADIATION are emitted by the sun. This can IRRADIATE you -- give you cancer, whatever. But it will not make you radioactive, anymore than bumping your body ... | [
"You can expose something to radiation and make it radioactive. The most common way to do this is through neutron activation. A sample is bombarded with neutrons, and the nuclei absorb the neutrons and become unstable to beta decay. ",
"This technique is really useful because it can be used as an analytical techn... |
[
"Can someone please explain magnetism to me"
] | [
false
] | I remember in science the basics of opposites attract and repulsion and attaction...plus I have advanced education in chemistry (if that helps frame your answer). I just don't understand how magnetism could work on a human scale or on a planetary scale. | [
"Most macroscopic magnetic phenomena are due to unpaired electrons. That's because each electron has a magnetic moment (about a thousand times stronger than nuclear magnetic moments), and these moments add up when the electrons are unpaired. Recall that spin angular momentum + charge = magnetism, so examining the t... | [
"you have an advanced education in chemistry and you don't know how magnetism works?",
"you must have slept through paramagnetic/ferromagnetic/diamagnetic/electron pairs parts"
] | [
"To my best understanding, and please correct me if I am wrong, It has to do with the orientation of the poles of the actual atomic structure. And somehow some materials such as [This}(",
"http://en.wikipedia.org/wiki/Neodymium",
") hold a \"charge/force\" better than say Iron."
] |
[
"Why don't we ever sneeze while sleeping?"
] | [
false
] | null | [
"REM atonia and trigeminal motor neurons that are responsible for triggering a sneeze being suppressed during non-rem sleep.",
"(see first link along with sources within)",
"Here is a more complete answer as to what suppresses / prevents sneezing during both Rem and non-rem sleep. My source lacked detail on th... | [
"This means that the motor neurons are not being stimulated, so they aren’t sending these signals to the brain.",
"This part of the explanation is incorrect. Motor neurons carry signal to the muscles to contract them. During REM atonia, they are not active, leading to temporary paralysis. I.e. when you dream duri... | [
"Yes, the need to sneeze woke you up.",
"Strong enough signals can override the brains sleep-centric-shutdown-state. Something was significantly irritating your nose"
] |
[
"Is there an equivalent to the \"Planck Length\" for time units?"
] | [
false
] | And if there is, shouldnt it be possible to calculate a momentous velocity of an object based on the fact that there's a "minimum" timescale? | [
"As ",
"/u/fishify",
" said, it's the Planck time. But it's ",
" the \"minimum\" timescale, as far as we know. It's the timescale below which physics as we know it can no longer be used to reliably calculate things. In order to understand processes occurring on shorter timescales, we need a new theory of phys... | [
"Yes, the Planck time. It's the time it would take for light to travel one Planck length, i.e., the Planck time = (Planck length)/",
", where ",
" is the speed of light."
] | [
"Also, in general the Planck units are just defined in terms of the basic constants such as the speed of light and the Planck constant. They don't have to correspond to a minimum anything. The ",
"Planck energy",
" is roughly equivalent to a full tank of gas. "
] |
[
"I just learned that the Aral Sea no longer exists and is now mostly a desert. Are there, and what are other comparable \"recent\" drastic changes of physical geography or biomes?"
] | [
false
] | Link to wikipedia article I'm a bit surprised I didn't hear of this before, since it seems like a perfect example of human-caused climate change. I'm also aware that many dams will create sizeable lakes, but this seems like it would be much smaller than the disappearance of the Aral sea. | [
"An important clarification, as discussed in the Wikipedia article you linked, the desiccation of the Aral is not primarily driven by climate change, but rather by diversion of water in massive (and poorly designed) irrigation projects to try to transform portions of central asia into an agriculturally productive a... | [
"Presumably, very little of the topography has changed so it's still a low point and if there was sufficient inflow (and the balance of inflow was still greater than evaporation) no reason it wouldn't refill. There has been a ",
"little bit of a recovery of the northern Aral basin after it has been physically sep... | [
"Does that mean the water would reaccumulate if the irrigation would be turned off?"
] |
[
"How are new experimental surgeries designed and tested?"
] | [
false
] | Warning: NSFW Picture I saw this picture on the frontpage today on scoliosis surgery: This got me wondering, how does a surgeon begin to design and test new surgeries? There seems so many that can possibly go wrong if done for the first time like the spinal surgery above. How can the first surgeon who did this be sure ... | [
"I'm currently working on a PhD in a Biomedical Engineering institute and while I don't work directly on testing medical devices I do work on the spine and be able to provide some insight.",
"Translation of a new device to a clinical setting is an incredibly long process that starts with in-vitro animal testing. ... | [
"Usually the surgeries will be developed at research hospitals, they will have to undergo review by a board of specialists, and then the candidates will be selected from those whom are deemed poor candidates for traditional methods. Usually the patients will be deemed to have very poor quality of life or terminal a... | [
"In general, you start with animal testing, then move to cadaver testing, finally on live people. These steps are not fixed. The idea is to thoroughly evaluate both the safety and the efficacy before moving on to real people. ",
"The procedure you're talking about is working on the spine, which is very dangerous.... |
[
"Can someone explain how the Many Worlds Interpretation actually works?"
] | [
false
] | [deleted] | [
"There is no collapse of the wave function in MWI. That is its big advantage, it doesn't have such an ill-defined process.",
"The split of the worlds naturally happen if you just let the wave function evolve. MWI doesn't require anything special for it. On the contrary: All interpretations that do not have many w... | [
"I think \"splitting\" is a surprisingly bad way of explaining the MWI. In this interpretation, there is one, universal wavefunction. When you do a measurement, you entangle the states of the measurement apparatus and the measured system, and the different components of the resulting superposition are what we call ... | [
"My question is, how does the duplication or split not require more energy than what was already contained within the particle? How is there a duplication without the need for added energy? If you don't need additional energy, wouldn't the resulting \"world's\" particle have less energy than the original one?",
"... |
[
"Is there a point in time in which the universe did not exist?"
] | [
false
] | null | [
"I am not professionally trained in this, but I've thought and read a good bit about it and related topics.",
"My understanding is that \"time\" is ",
", so by definition, no, there is no point in time in which the universe did not exist. Time began when the universe began. Remember that time is a human concept... | [
"This is pretty much the whole story. The beginning of the universe is considered (by most physicists) to be the \"beginning\" of time, in the sense that any pre-big bang phenomena are causally disconnected from our universe."
] | [
"pre-big bang phenomena",
"This is the part that I can't wrap my head around.\nAre you saying that there can be pre-time phenomena?"
] |
[
"Why is it the positioning of my body affects a wireless FM transmitter signal? (also, how can I boost this signal?)"
] | [
false
] | I have a mp3 player wireless FM transmitter, and I've noticed several times that when I touch it or hover my hand above the transmitter the signal is boosted or clarified. That is, the static disappears from the audio. What causes this? Also, is there something I can do to have this effect without hovering my hand abov... | [
"Errm, that article is a little nutty.",
"What you are describing is the proximity effect. Your body is conductive and can be thought of as the plate of a capacitor, with your surroundings being the other plate. When you touch the antenna, your capacitance is added to the receiver circuit, and depending on the tu... | [
"Capacitive coupling + shitty antenna in the transmitter and/or poor ground on the transmitter. ",
"A good performing antenna will not benefit from hand action, you're making up for a source of loss.",
"Two five foot wires, one to the ground of the transmitter (or to vehicle frame) and the other replacing the e... | [
"No, your thinking of if you point it at your chin or towards your head since your skull ends up acting as a couple and parabolic dish"
] |
[
"How does the recent Tonga eruption compare to the famous Mt. Vesuvius eruption?"
] | [
false
] | Just as the title asks. Since most of the public has an idea of the Mt. Vesuvius eruption how much does the recent eruption compare. We have a TON of scientific and recorded data with the recent eruption so how accurately can we compare it to Vesuvius? | [
"The standard way we compare volcanic eruptions is through the ",
"volcanic explosivity index or VEI",
". It's a slightly weird scale in that it is kind of a mix of quantitative values that we can estimate for modern and ancient eruptions (e.g., volume of erupted products), quantitative values that are directly... | [
"It’s seems like it will probably be lower, because most of the plume was actual water vapor, and not ash, because of the nature of this eruption. The total volume of solid materials is probably pretty low (according to USGS, unfortunately I don’t have a link, but they reported this on one of their Facebook portals... | [
"Mt. St. Helens vaporized the top 1/4 mile of the mountain as it existed pre-1980 leaving an off-center pit. Total energy released was estimated at 1600 Hiroshima atomic bombs equivalent. From this aspect, some of the modern VEI 6 and VEI 7 eruptions would have rated between 3000 and 5000 Hiroshima bomb equivalen... |
[
"During sperm production, what is the mechanism which guarantees that half of produced sperm have an X chromosome and half have a Y chromosome? In other words, why are 50% of us male and 50% of us female?"
] | [
false
] | null | [
"It's called ",
"meiosis",
" the original cell that the sperm comes from has 23 sets of chromsomes. One of those set pairs is the XY pair. During meiosis the chromosomes split up. 2 sperm cells get a X while 2 get a Y. It's a 50/50 shot just which sperm cell fertilizes the egg."
] | [
"Actually, ",
"more births are men than women, and we're not sure why",
". This seems to be true ",
"around the world.",
"After birth male mortality is generally higher at any given age. Men are more susceptible to heart attacks and strokes, men are more likely to engage in risk-prone or reckless behavior, ... | [
"The key to understanding this is to recall chromosome pairing. Normal cells have chromosomes that come in homologous pairs (i.e. two versions of DNA coding for basically the same genes, though with variations. Each chromosome has a version they inherited from their mother and father.). The 23rd chromosome, the sex... |
[
"What is actually being referenced as “average” temperature?"
] | [
false
] | I always see climate change referenced as a change in average temperature. What average? Is this the recorded high temperature every day/365? Or is it the average of every June 27, year over year? Or something else? It just seems underwhelming when I hear a change in average temperature of say 2-3 degrees, even though ... | [
"The exact answer to this will depend a lot on the context, but it's important to remember that by definition, ",
"climate is an average",
" so, by proxy changes in climate are changes in the average, hence why this is really the only way it can be discussed. ",
"In terms of what is being averaged, it will de... | [
"On the \"2-3 degrees doesn't sound bad\" point, one thing we fail to communicate effectively is that that is ",
" temperature, and most of the globe is water. Water takes more energy to heat that land. A 2C global change is more like a 3C change on land and 1.5 C change in water, 3C is 4.5C on land and 2C on wat... | [
"Thank you for the additional clarification. I think the issue I’m having is when you read a news article about it and they quote a change in temperature it’s usually not obvious what they are talking about. There may be references listed but usually I don’t see it clearly referred to in the sentence. I am sure tha... |
[
"Why don't we use femtosecond (or shorter) radio pulses for communication, and would we be able to see (potential) aliens using such short pulse radio?"
] | [
false
] | GSM (for cell phones) uses 577 microsecond timeslots. It would seem to be more energy efficient and longer range to use more power with extremely short pulses as opposed to continuous broadcasts. So why don't we use this? And could our SETI watchers detect such use from aliens? Also, is there a limit to how short a rad... | [
"An important issue to understand here is bandwidth, how much frequency space you have to communicate. With your GSM example, the carrier frequency is around 1GHz, which means that the electromagnetic field used to transmit the information is oscillating one billion times per second. ",
" The 577 microsecond time... | [
"You can modulate a signal with a faster bit rate than its carrier, given the right combination of bandwidth and signal-to-noise ratio. As discovered by Claude Shannon during WWII."
] | [
"Most radio waves are line of sight, other than the lower end which can bounce off the sky or diffract with the curvature of the earth. Note that line of sight doesn't mean ",
" line of sight, there are transparent things for radio waves that aren't for visible. This is why you need cellphone tower everywhere and... |
[
"How exactly does injecting poultry with powerful antibiotics like Colistin affect the general population's resistance to infections?"
] | [
false
] | I'd read an alarming article wherein Colistin is heavily injected into Indian chickens and the implications of such practices. I was wondering how is the resistance to these medicines formed actually? Will those affected by this include people who don't eat these chickens as well? Link to article: | [
"Example: take a petri dish with a bacterial culture inside and expose the bacteria to the latest antibiotic. All bacteria will die because they have no protection against it. Now repeat the experiment a few more times and you'll find that ",
" some bacteria will survive the antibiotic treatment. That's because t... | [
"Ah okay. That clarifies things quite a bit. So the drug resistant strains are now likely to spread from human to human too is it? Even a person who never eats chicken is going to be affected isnt he?"
] | [
"You are right, in this case eating chicken is not the factor. It is not us becoming resistant to antibiotics, its bacteria. "
] |
[
"What dictates the shape and color of afterburners and rocket flames?"
] | [
false
] | The color, the conical shape, the rings, etc. | [
"The color comes from the chemicals being burned. Each element or compound had certain allowable electron energy levels. When burned, these compounds' electrons are raised to higher energy levels. When the electrons fall back down to lower energy levels they emit photons with a color corresponding to the frequency ... | [
"Does altitude effect it? Also, what about the shape? Picture a jet fighter's afterburner, how it has those different colored rings and sometimes an hour-glass shape within the flame... Yeah. But how?"
] | [
"This is just my speculation but I think the shapes are caused my temperature gradients. The well defined shapes are due to the discreet electron energy levels. Ex: 400-500 degrees all correspond to the same energy drop (numbers pulled out of my arse)."
] |
[
"Why does hot (just boiled) water, make a different sound when poured?"
] | [
false
] | null | [
"Have you tried pouring cold water from the same kettle? :P",
"On a more serious note, the intensity of propagation of sound happens to be a function of viscosity (among other things) Viscosity is heavily temperature dependent. ",
"Here's Stoke's Law for Sound Attenuation",
"At roughly room temp, the viscosit... | [
"That makes perfect sense to me. Thank you clearing up an age old question!"
] | [
"Are you referring to the sound that water makes as it leaves the kettle or as it enters the cup? If the latter, it's because the cup is filling up, changing its pitch."
] |
[
"Is there a study on the health effects of frequent showering?"
] | [
false
] | null | [
"You're calculating the expected value of the number of accidents, he's calculating the probability of at least one accident. In that case, assuming the probability is independent and identically distributed, you're both right.",
"If you flip a coin twice, the probability of at least one tails is 3/4, but the exp... | [
"Say you shower everyday from age 10 to age 85, your risk of an accident would be one. ",
"Wouldn't it be:",
"Chance of not having an accident any given day = 0.9996",
"Chance of not having an accident all 25000 days = 0.9996",
" = 0.3679",
"Chance of having at least one accident in those 25000 days = 1-0... | [
"Heres one from pubmed: ",
"http://www.ncbi.nlm.nih.gov/pubmed/20434775",
" . Seems that a carcinogen- trihalomethanes (THMs)- forms in warmed chlorinated water which many people would use in their showers. The longer one showers the longer one is exposed. This increases cancer risk. ",
"Here is another f... |
[
"If organism A and organism B can interbreed, and organism B and organism C can interbreed, does that necessitate that organism A and organism C can interbreed?"
] | [
false
] | null | [
"No, ",
"That is why plant breeders use a technique called bridge crossing to transfer suitable genes from one species to other, if they are directly incomatible but have a common compatible species"
] | [
"The answer is no, interfertility is not transitive. The wikipedia article on ",
"ring species",
" provides several examples."
] | [
"No. Example: A and C are male, B is female."
] |
[
"Do animals recognise/protect their grandchildren?"
] | [
false
] | [deleted] | [
"Elephants have very strong maternal hierarchies, it's usually one of the oldest females leading groups. Being long-lived, I would assume the relationships even beyond grandchildren are known and protected. The wiki page for African elephants has a brief treatment of their social structure: ",
"http://en.m.wikip... | [
"Primates and some tamarins exhibit this kind of behavior. It's considered a form of alloparental care, and research is being done to see if there is any connection between this and human alloparental care from grandparents. Sarah Hrdy has a great book that came out within the last year or so titled Mothers and Oth... | [
"Ditto, they're not my focus but I think they're fascinating.",
"Fun anecdote: When I was a teenager I did one of those \"zoo teens\" volunteer jobs that most zoos have. The elephant keeper told me that our zoo's two elephants, Mona and Suzy, were childhood friends. They had been born into a wild herd that was... |
[
"How many miles / kilometers is a lightyear? How many mph / kph is that?"
] | [
false
] | null | [
"Thanks captain obvious. Thought it would spark some cool conversations"
] | [
"I don't see how a question of singular definition could spark any \"cool conversations\". Maybe you should work on rephrasing your questions to make them better. "
] | [
"Google does unit conversions. Just type in \"1 light year to km\". "
] |
[
"How does temperature of air and density of air and gases dictate the troposphere?"
] | [
false
] | Can someone resummarize the troposphere section? I'm having trouble understanding it fully. Does the air temperature decrease with increasing altitude because there are less gases to be heated? Also inversion occurs because now the sun is gone and warm air rises so does that mean suddenly there is more gas in the incre... | [
"Air temperature decreases with increasing altitude because the atmosphere is (essentially) heated from below. Radiation from the sun increases the temperature of the surface, which by conduction to surface layer air molecules begins to increase their temperature. Convection proceeds to increase the temperature of ... | [
"Hey thanks for the response very helpful! So does the composition of gases in the air change at night due to warm air rising? Or does it still stay the same as in the day?"
] | [
"As far as the composition goes, there is a cycle of carbon dioxide which relates cars on the road, etc. (",
"http://www.inchem.org/documents/ehc/ehc/v013eh02.gif).CO2",
" concentrations rise during the morning and drops off later in the day, with the drop off being related to a thickening boundary layer (allow... |
[
"Does artificial gravity require lots of energy to maintain rotation?"
] | [
false
] | If there is a donut shaped room rotating at constant speed (along the axis through the center of donut), and two people standing at the opposite side of the room (heads facing center of donut of course), can the system theoretically spin at this rate without major loss in kinetic energy, just like how the earth is spin... | [
"There is no energy required to keep the torus rotating in vacuum/space. Thats conservation of angular momentum. In fact it you only need energy to accelerate or slow down the rotation.",
"You can even increase rotational speed by using the sun wind. Like a mill. ",
"The amount of friction in interstallar space... | [
"It doesn't take any energy input to keep an object of any shape rotating in space. Yes, this includes the people inside a craft that was rotating for an artificial gravity effect.",
"The reason why it doesn't require any energy input is that no work is being performed. Just a person standing there, feeling the e... | [
"Their bearings, and the pivots on their gimbals, are not perfectly frictionless. As they move around the earth, the direction and strength of the local gravitational, magnetic and electric fields vary. All of these add up to cause very slowly building deviations that have to be corrected from time to time."
] |
[
"Will we ever be able to not only visit Proxima Centauri but see whether it’s planets in the Habitable Zone have life in the next 50 years?"
] | [
false
] | null | [
"It's very unlikely that we will send a probe to Proxima Centauri within that time. People have speculated about getting a probe up to 10% of the speed of light, but it's not something that there is a real plan to do. Essentially, we would need to launch such a probe ",
" to get there within 50 years.",
"Howeve... | [
"The partial problem with these really fast probes is that even if we can get them to that speed, we wouldn't be able to slow them back down. It isn't like we could send a probe to another system and orbit something. It would be limited to a flyby at incredible speeds."
] | [
"The breakthrough starshot",
"https://en.wikipedia.org/wiki/Breakthrough_Starshot",
"According to wikipedia would reach 15%-20% c, altough initially I just heard about 20%.",
"And atleast according to mainstream media, the launch could happen after 20 years, meaning less than 50years untill pictures arrive."
... |
[
"How is angular momentum conserved here?"
] | [
false
] | In , the system starts with some net linear momentum, but no angular momentum. Then, the small block bounces off of the bigger rectangular block and they both have a certain amount of rotation, giving them both angular momentum. So the system starts with zero angular momentum and ends with a non-zero angular momentum. ... | [
"This system starts with angular momentum relative to the center of mass of a system.",
"An object moving in a straight line does have angular momentum relative to an axis that does not lie along the line. This is often a point of confusion, but one does not need to be moving in a circle to possess angular moment... | [
"Pretty much what zeug said. Total angular momentum is conserved with respect to any axis. ",
"To illustrate this simply, let's pick an axis going in and out of the screen, through the bottom of the rod. The system will start out with some angular momentum with respect to this axis, from L = r cross p of the m... | [
"So, just to reassure myself that I understand this, the total amount of angular momentum in a system is completely dependent on the abitrary placement of the reference axis? (is it an axis or a point, btw? I've read both. Im guessing axis for 3d problems and point for 2d problems?) But no matter what axis or point... |
[
"Double slit - why are there so few images of the non destructive pattern formed by observation/detection at the slits?"
] | [
false
] | [deleted] | [
"This of course only happens in the quantum, single particle double-slit experiment. You will ",
" observe such a behaviour in the normal double-slit setup, which is an experiment in classical optics. The waves in the experiment almost anyone can do at home are macroscopic classical waves."
] | [
"I get that. What I am looking for is the result of a detector being used at the slits, regardless of the version of the experiment."
] | [
"I've seen plenty of images displaying photon detections as \"dots\"before"
] |
[
"What is so \"special\" about the toe that it produces a toe nail? Why can't other places of skin do this, like my elbow?"
] | [
false
] | [deleted] | [
"All of your body does. toe nails are made made of keratin, same as dead skin cells and hair, so really your body is covered with it. There are differences of course. Calcium is added to nails which make them stronger, also hair grows vertical, nails grow both horizontal and vertical and form layers. To ask why a n... | [
"Basically your body has chemicals that turn the actual use of genes on an off. Some of these fluctuate every second to control energy use, creation of chemical messengers, honestly just about everything your body makes. In regards to body layout, these chemicals are only present in early development. A big way the... | [
"The keratin shield, which is made up of the nails, and hair, is as old as the mammal family of animals, probably older, if we are descended from the mammal-like reptiles. It was probably originally for protection from sun, heat, insects, whatever, but, over time, different parts have adapted to meet the needs of ... |
[
"Does your diet, as a child, really affect how tall you'll be later in life?"
] | [
false
] | [deleted] | [
"Absolutely! You can see direct evidence of this in South Korea, where up until maybe 40 years ago, food was scarce, and people didn't get as many calories in their diet like they do today. Since then, they've had rapid development and better nutrition. (Although \"better\" probably isn't the best choice of words... | [
"Why would you down vote this post? Sure he didn't actually post the data, but he's on the right track. "
] | [
"Why would you down vote this post? Sure he didn't actually post the data, but he's on the right track. "
] |
[
"Can we overtake either of the Voyager probes with current tech?"
] | [
false
] | If NASA got a wild hair and decided to re make the voyager probes could they make them faster and catch up, over take them? Would they have a camera system that still works? Would the power connections last as long or longer? Can we go further faster? edit: NASA has the budget of the DOD. Hypothetically. | [
"The voyager probes managed to get their high speed from a rare planetary alignment that will not be happening in a very long time. The probes both used a slingshot maneuver around Jupiter and Saturn to attain their high velocitys."
] | [
"You didn't give a time frame so it's certainly possible. It would take decades to overcome though. Voyager I is currently leaving the solar system at a speed of over 38,000 mph so that's a big head start. Even if you were to double it's speed it would still take 30 years to catch it and you would still have to be ... | [
"Definitely no. He'd have to develop a new propulsion system (more than 10 years to develop), one that's very significantly better than anything that has ever existed. Something like a fission saltwater rocket or a project orion style nuclear pulse propulsion system. The probes are currently hundreds of millions... |
[
"Chemically speaking, what happens to your body when you consume alcohol and become intoxicated?"
] | [
false
] | [deleted] | [
"Too busy studying to type out my own answer but here's somewhere to start: ",
"http://en.wikipedia.org/wiki/Short-term_effects_of_alcohol",
"the TL:DR is that alcohol (ethanol) inhibits several neuro transmitters which cause your brain's pathways to work at a greatly decreased ability."
] | [
"Yeah, I just feel like people post here because they want a well constructed answer. I feel like giving a 'let me google that for you' answer is a disservice. Having another person filter through the information and present it in a concise form emphasizing the important parts for the intended audience just makes ... | [
"I am not a moderator but feel that I speak for the majority of subscribers who, along with you, see the same questions asked over an over..",
"People post general questions here because they want to know a good source of information.. even links to it. If google/wiki can provide it.. then just link to it. Mentio... |
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