title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"My 4 year old wants to know: Why do magnetic fields exist?"
] | [
false
] | null | [
"Most people being honest will tell you they don't know. There are very few people I'd accept an answer from, because you're trying to explain why a fundamental force exists. You can ",
" magnetic fields from electric fields, but that fails to explain why it is present. Getting to the real root of the answer requ... | [
"That's an incredibly deep question for a 4 year old! Were they just introduced to magnets? Tell them that magnetic fields and electric fields go together like two sides of the same coin.",
"Electric fields come from charges. ",
"Magnetic fields come from when those charges move around."
] | [
"You know those hairy rubber balls for kids? When you hold it still you get spiky hair pointing out away from the ball, this is our electric field. When you move the ball around or spin it, the hair gets warped around, this is our magnetic field. Think a 4 year old would get that?"
] |
[
"Why isn't the human body comfortable at 98.6 degrees if that's our internal temperature?"
] | [
false
] | It's been hot as hell lately and got up to 100 yesterday. I started to wonder why I was sweating and feeling like I'm dying when my body is 98.6 degrees on the inside all the time? Why isn't a 98 degree temp super comfortable? I would think the body would equalize and your body wouldn't have to expend energy to heat itself or cool itself. And is there a temperature in which the body is equalized? I.e. Where you don't have to expend energy to heat or cool. An ideal temperature. Edit: thanks for all the replies and wealth of knowledge. After reading a few I remembered most of high school biology and had a big duh moment. Thanks Reddit! Edit: front page! Cool! Thanks again! | [
"Your body is a like a heater that is always on; it cannot be turned off because that heat is produced by and required to maintain a delicate environment for your life processes.",
"Heat only flows from hot to cold. If temperatures are equal, there is no cold for the hot to flow to.",
"If 98F is ambient tempera... | [
"So your body puts about the same heat out as a 50w lightbulb.",
"You're constantly making heat, constantly metabolizing. ",
"If it's around room temperature, you are able to radiate the heat away without using any sweat. The variance in temperature is able to keep you feeling fine as is.",
"But the closer yo... | [
"So what is happening then in hot tubs or especially saunas where the temperature is often well over 98.6?"
] |
[
"Why does heat try to escape?"
] | [
false
] | null | [
"http://en.wikipedia.org/wiki/Entropy",
"This has been removed because it’s a commonly occurring question on ",
"/r/AskScience",
" or a question that can be answered easily through a single Google or Wikipedia search. To check for previous similar posts, please use the subreddit search on the right, or Google... | [
"Thanks for the link to the wikipedia page. Unfortunately, I'm finding this to be a bit too complicated for me to understand still. Could I submit a question to explain it like I'm 5 instead?"
] | [
"Hi there,",
"I'm not a mod of ",
"/r/explainlikeimfive",
", but from my perspective, I don't see why not. Good luck!"
] |
[
"Is it important to drink a lot of fluids when sick with a flu or common cold?"
] | [
false
] | [deleted] | [
"The vast majority of the time, your body can get rid of excess water. There are a few pretty specific instances when you can get overhydrated, ill tell you about two really quick.",
"Psychiatric conditions: There are certain psychiatric disorders in which a person feels the need to be constantly drinking water, ... | [
"Even if you are not bedridden with a very high fever and sweating, if you have the flu or a \"cold\" you will have a somewhat elevated body temperature. Because of this, your body will be losing more water than normal, even if you cant notice it (much of your daily perspiration is unnoticed anyway). ",
"The comm... | [
"I've often wondered about that eight glasses of water thing. I'd heard it's too much as well, but I've never heard what ill effects that level of overhydration can cause. The human body seems pretty adept at getting rid of excess water--or maybe I just have a tiny bladder."
] |
[
"Can you put out fire with petrol?"
] | [
false
] | I was wondering if it would be possible to put out fire with petrol. Would the 'wetness' of the petrol put out the fire if there was enough of it, or would the petrol alight too quickly for that to happen? | [
"If you can exclude oxygen from the reaction then yes. This is not the case for things like gunpowder though since they have their own oxidant in the reaction already."
] | [
"If you had a sufficient volume of gasoline, at a temperature far below its flash point, MAYBE. It's all about heat. If enough of the gas gets to its flash point, in contact with oxygen and the flame, it will light. "
] | [
"I should have added, you can extinguish a lit match in high flashpoint fuels, like diesel or JP-8, don't try this at home please."
] |
[
"is there a correlation between the Sun's activity and Global Warming?"
] | [
false
] | The temperature where I live (Ontario, Canada) rose 16 deg. C higher than average for this time of year. This corresponds directly with the solar flare activity reaching earth. Can this be coincidence and can it explain why global warming is occurring? Edit: Thank you all for your answers. | [
"There are several effects that solar activity might have on Earth's climate.",
"First, of course, is direct luminosity changes. If the Sun's energy output varies by even a fraction of a percent then that could still have a significant impact on the Earth. In general the long term average of solar energy output i... | [
"Solar activity varies between minimums and maximums every ten years. This is a constant trend that has not changed for millions of years. This recent solar storm has occurred because the sun is nearing a solar maximum in 2013. Meanwhile the process of global warming is completely unrelated. We have released so muc... | [
"Good stuff here. I just wanted to add that while solar cycles aren't really responsible for daily or very short-term changes in weather or climate, they can occasionally factor in on slightly longer time scales, such as a year. Solar maxima and minima will occasionally cause some deviations, such as ",
"The Ye... |
[
"What happens in a light bulb when it burns out? Is it random or is there someway to know it's about to happen?"
] | [
false
] | Every light bulb I've ever had has always blown out when I'm trying to flick it on, is it possible for them to burn out in the middle of use? If I never turned off the light assuming a constant surge free power source, would the light stay on forever? | [
"The filament of a light bulb is just a thin piece of metal, usually tungsten. When it's heated, little bits of tungsten can evaporate away and make slightly thinner spots. The thin spots tend to get hotter since the same amount of electricity is passing through a thinner wire, which increases the evaporation rate.... | [
"You're right, I left out the effect of turning the bulb on and off hundreds and thousands of times. This causes fatigue in the filament. I posted a link to wikipedia in a comment above that can help ",
" things. Eh? Eh? Who says there's no room for humor in AskScience?"
] | [
"The commenter was right, thermal shock does have a large effect on the filament. Your argument against it could be thought through more carefully, though.",
"Consider this: the difference in temperature between winter and summer is, say, 50 degrees C (122 F). The difference between room temperature and the tempe... |
[
"Why is Australia filled with so many dangerous animals/plants?"
] | [
false
] | I saw a thread in reddit mentioning a tree that can kill you... And it has really gotten me wondering, why are so many deadly animals and plants (venomous/poisonous) found in Australia? I mean, I think I understand evolution, but why would such a large number of them be found in Australia? If I recall correctly, I remember watching a documentary in Discovery about the ten deadliest animals, and like six or seven would be found in Australia... That's insane! So, is there any reason for this or is Australia just unlucky? I read though all the replies, but I can't reply to all to say thanks. But this has been highly educational, so thank you! It appears it was a misconception from my part. I'll be honest, I used to believe I would never have the guts to visit Australia, but now I feel like I could go. | [
"Australian ecologist here: my god, there is a lot of rubbish being touted in this thread.",
"Okay, first up: there are not more dangerous animals in Australia then elsewhere. This is a misconception fueled by silliness and exoticism. The famous list of Australia having nearly all of the world's most venomous sna... | [
"FYI \"passively toxic\" is the same as poisonous. Venomous is used when toxins are used offensively. IE; frogs are poisonous, snakes are venomous."
] | [
"This is absolutely incorrect, because there aren't more dangerous animals in Australia than elsewhere in the world. You're speculating and providing the wrong answer."
] |
[
"The size of the solar system is usually measured by how large it is from end to end, but how \"tall\" is our solar system?"
] | [
false
] | I know there's no relative up or down (or top or bottom) in space, but how large is our solar system measured up and down perpendicular to its plane? | [
"It really depends on which objects you want to include in your definition (the \"length\" of the solar system depends strongly on your definition too), and even then, what you're using as a reference plane. The ",
"Oort Cloud",
" a (hypothetical but commonly accepted) body of comets orbiting the sun is roughly... | [
"Thank you for the incredibly detailed answer. I've got a potentially silly follow-up question, but: If I'm remembering my basic astronomy correctly, the asteroid belt isn't spherical, right? It's roughly a ring the encircles the inner planets?",
"Would the \"height\" of the asteroid belt be comparable to the dia... | [
"More or less by definition, yes, though there are many asteroids whose orbits bring them closer to the Sun than Mars or farther than Jupiter (some have quite interesting orbits, like the Trojan asteroids, which co-orbit with Jupiter about 60 degrees ahead of or behind it). Like the Kuiper Belt, the bulk of the ast... |
[
"So Earth's magnetic field protects us from cosmic rays, why not generate one around space craft?"
] | [
false
] | As I understand it Earth's magnetic field isn't all that strong though it is large. Would it be too difficult to generate a magnetic field without damaging electronics or communications? Or would it use too much electricity? Or would it create some kind of charge problem? | [
"It is possible, there's actually a ",
"paper",
" on just that subject. Generally speaking it's more efficient to create a magnetosphere than merely a magnetic bubble. The reason why it hasn't been done yet is that it hasn't been absolutely necessary. The biggest danger is in interplanetary space, and the probe... | [
"It's a serious question, if the idea is impractical - let them know why. I assumed ask science was for teaching people stuff, not demeaning their questions."
] | [
"It's a serious question, if the idea is impractical - let them know why. I assumed ask science was for teaching people stuff, not demeaning their questions."
] |
[
"How do we know how good animals' eyesights are? Aside from observation (watching a hawk hone in on its prey from 200 ft high), how is it determined?"
] | [
false
] | From time to time I wonder how poor eyesight affects an animal in the wild. I imagine if I had to live life in the era before eyeglasses, I would be so screwed, even as a human. I can't imagine what kinds of detrimental effects poor eyesight would be on an animal in the wild. I'm very curious as to which animals (besides bats) have naturally poor eyesight? | [
"There are two types of photoreceptors, rods and cones. Rods are more sensitive to light (dim light can activate them), cones give us details, colours, acuity, etc.",
"There is a segment in the retina called fovea centralis, within which is the macula. The macula has only cones, so when the light hits the macula,... | [
"I don't think this answers OP's question, but it is cool information nonetheless."
] | [
"Yes, I guess I'm unclear on how I'm asking it, and I hadn't thought out my question well. I guess through dissection, we can determine what kinds of cells (rods and cones) they have. And then I wonder how we know how each cell functions. I guess that part would be done through lab experimentation with live animals... |
[
"Can we make elements of the period table in the lab?"
] | [
false
] | null | [
"I mean huge amounts of them, in the scale of thousands of metric tons for example.",
"No, we can't do that.",
"We can create small amounts of certain nuclides at a time using reactors, and ",
" small amounts of pretty much anything you want using accelerators."
] | [
"very small amounts of pretty much anything you want using accelerators.",
"So, we know actually how to make the elements, accelerators. But the problem is the energy needed?"
] | [
"The energy, the cost, and the time it would take to create macroscopic amounts of material is just totally unfeasible."
] |
[
"The typical rule of thumb is chemical reactions occur more quickly by increasing temperature. Are there reactions that occur more quickly at 'cold' temperatures?"
] | [
false
] | null | [
"At the scale of a single individual reaction this is ha hard physical fact rather than a mere \"rule of thumb\". A stable compound is a local minimum of energy in terms of the geometric coordinates of the atoms, and the potential-energy surface is continuous. That's a formal way of saying you ",
" have to go up ... | [
"There are examples of a reaction rate increasing at freezing temperatures. The reactants stay in solution and the concentration of them is increased.",
"Here is one example of this:\n",
"http://pubs.acs.org/doi/abs/10.1021/jp9525806",
"There's another recent example of this occurring for an enzyme-catalyzed... | [
"An important case of this: B can be the reverse reaction to A. If A is exothermic (releases energy), its reaction rate will typically increase slower than the reaction rate of the reverse reaction. The ",
"Haber-Bosch process",
" has this issue for example. You want high temperatures to speed up the reaction ... |
[
"How do we experience life as a single conciousness if there is no 'central hub' for the brain? Or is there?"
] | [
false
] | null | [
"We don't know.",
"\"Consciousness\" isn't even slightly-well defined."
] | [
"Since every atom in your body is replaced roughly every seven years, I would lean more towards the idea that continuity of experience is an illusion and you weren't actually that person you see in a seven year old photo, that person is gone.",
"But no one knows for sure, consciousness is ill-defined."
] | [
"That isn't actually true - it appears that many atoms, especially those in the brain, remain for an entire lifetime (or much of one).",
"Besides, if you argue that a change of a specific atom for another identical atom would change a person's consciousness, then you have to invoke some law of physics that nobody... |
[
"Conceptual explanation for the sum of all natural numbers (1+2+3=-1/12)?"
] | [
false
] | Sooooo.... I was looking for advice on my dating profile and everyone freaked out about the "sum of natural numbers "(I had it listed on my things I think about). And now I'm a bit concerned because I show this example to my high schoolers when they ask me to blow their minds and I want to make share I'm not misleading them when I explain this to them conceptually. I understand there are rigorous proofs, hand wavy proofs, controversial proofs, BUT, I want to see if this makes sense conceptually as this is how I've been explaining it to my students. Ok so I generally use the proof from that So if we take the series ,1-1+1-1+... and we were to use it model a light switch and consider on=1 and off=0 and we keep flipping the light switch on and off (for infinity) then the total number of photons, the total intensity, the total luminosity in the room is 1/2 what it would normally be at any moment in time (avoiding any sort of multi-photon or non-linear effect) and this is true as long as the switch is being flipped on and off. As soon as you stop, this no longer represents an infinite process and will equal either 1 or 0. Is this okay? Is this an accurate description/analogy? Secondly, if that conceptual example is satisfactory then can we say the same of the sum of all natural numbers? It is not a trick, or a fallacy but a meaningful answer that is only true within the context of a problem and is only true when the process in question is infinite? Third, is it fair to say that the answer we get is meaningful within the context of a specific problem in a field like Quantum Field Theory, in the same way that an answer like 1/0 would be meaningful in Cosmology? My kids really get into it and they have taken it upon themselves to try to "prove" other infinite series on their own. Its pretty amazing. Their answers are WRONG, but the effort and the spike in their level of interest, specifically in math, is insane. I'd like to keep using it. Anyway, thanks for reading and for any insight you can offer. | [
"Here is what's really going on:",
"The sum 1+2+3+... does NOT equal -1/12. Rather, there are regularization techniques that have us replace the infinite sum 1+2+3+... by -1/12.",
"In mathematics, we can define something called the Riemann zeta function. For complex numbers with real part greater than 1, ther... | [
"What i really don't like about that numberphile video is that they sweep things under the rug in a misleading way.",
"So if we take the series ,1-1+1-1+... and we were to use it model a light switch and consider on=1 and off=0 and we keep flipping the light switch on and off (for infinity) then the total number ... | [
"please don't teach them that, especially not with the numberphile video in this handwavy way, it's extremely misleading. please don't teach things you don't understand well enough.",
"i'm sure there's a lot of challenging things, that you understand well and might motivate them in the same way.\nteach them ordin... |
[
"Can bacteria, viruses, etc. get diseases just like humans or plants?"
] | [
false
] | If bacterium, viruses, fungi, etc cause disease, can they themselves get a disease? | [
"Bacteria can be infected by ",
"bacteriophages",
", and they can be predated upon by ",
"bacterivores",
".",
"Viruses can be infected by ",
"virophages",
", though these are much rarer than bacteriophages and have only been discovered relatively recently.",
"Fungi can be infected by ",
"mycovirus... | [
"I wonder if there are virovores and we just haven't discovered them yet 🤔"
] | [
"Vira are probably too erratic to count upon for sustenance, meaning that only vira themselves would be capable of existing in a state that would allow this, but since they aren’t alive/capable of autonomous replication they wouldn’t be viable for reproducing via another virus either.",
"It doesn’t mean it doesn’... |
[
"At what speed, in MPH, is blood pumped around the body?"
] | [
false
] | null | [
"Cardiac output is about 5.25 L/min, or 5,250 cm",
" /min",
"Aortic root diameter is about 2.4 cm on average, with cross sectional area of 4.5 cm",
"Therefore the average speed of blood flow in the aorta is 1167 cm/min.",
"Convert to MPH and you get about 0.5 MPH on average.",
"That said, the heart pumps ... | [
"I am not a medical doctor. But, curious about the answer to your question, I found some journal articles on the subject.",
"Velocity of Blood Flow in Normal\nHuman Venae Cavae",
"Evaluation of blood flow velocity in the ascending aorta and main pulmonary artery of normal subjects by Doppler echocardiography.",... | [
"This is an interesting question. You might feel your heartbeat and your radial (wrist) pulse nearly simultaneously and be tempted into thinking that your blood is traveling that fast around your body. Alas, what you are feeling is just the pressure wave (which is damped gradually by the compliance of blood vessels... |
[
"Can you drain a AA battery by touching both ends with your fingers?"
] | [
false
] | If I were to hold a AA battery with my index finger on one end and my thumb on the other for a long enough time, would the battery get drained? | [
"I just measured my thumb-finger resistance as ~1 MΩ. (I tried to approximate the contact area you would get with a battery, but that number will still vary a lot depending on how moist your skin is.)",
"1 MΩ connected to a 1.5 V battery means 1.5 uA of current will flow. According to the Wikipedia page on AA b... | [
"I wet my fingers and used two nickels to increase the contact area and the result was around 200 kΩ. A common ",
"CR2032",
" has a voltage of 3 V and capacity ~200 mAh so you would drain it in roughly 1.5 years, which is significantly shorter than the battery's shelf life. There are other lower-capacity batt... | [
"It's a combination of several factors. First, the voltage is higher, so more current will flow if all else is equal. Second, the tongue is generally wet, which makes it significantly more conductive (lower resistance) than dry skin. Third, the terminals on 9v batteries are right next to each other, while on a b... |
[
"How does evolution work on the most basic of levels?"
] | [
false
] | This is going to be difficult for me to put into words, and may sound extremely dim-witted, so please bear with me. When an animal evolves, even slightly, how does that animal's DNA know how to develop itself in order to get better acclimated to its surroundings? In other words; on a molecular level, is the DNA structure somehow communicating with the animal's anatomy in order for it to revise itself for the animal's betterment? How does the DNA take in information from the host body's surroundings and then have an answer as to what it can specifically change within itself to give future generations an easier life? Imagine this hypothetical situation. A group of people begin living in a lightly flooded area. Slowly and after many years of living in this forever moderately-flooded area, the offspring begin developing webbed feet. How does the DNA/genetic composition of those people recognize that webbed feet will give them an easier time when walking about? | [
"There is nothing willful about evolution. It is a blind process.",
"Let's think about your genome and your descendants for a second. Your genetic code is composed of about 6 billion bases (each A T C or G in your code is one \"nucleotide base\") spread out over 46 chromosomes (a chromosome is just a linear molec... | [
"The DNA does not respond to its surroundings. Evolution is not goal driven. It occurs blindly through a series of random steps.\nSo what happens is as DNA is replicated occasionally there is a mistake in the copying (transcription). This occurs very rarely, usually once every multiple millions of base pairs, but ... | [
"It seems you have confused transcription with replication, or perhaps just accidentally typed the wrong word -- it happens! But for accuracy's sake, a correction: When mutations occur during DNA replication, those mutations are heritable, and can be acted upon by natural selection as you described. If there are er... |
[
"Coming from a 3rd year electrical engineering students perspective, I know how static electricity works but what I don't know is why it works essentially. What I'm asking is; why do some materials hold a better charge than others and while one material likes to gain a negative charge, Visa versa?"
] | [
false
] | By Visa versa I mean another likes to give away electrons. I figure it has to do with surface area in some instances like with fur or styrofoam but with glass and other non conductors that can have the same surface area I don't know where these extra electrons or holes are stored. | [
"Our basic understanding of static electricity still seems to be pretty murky.",
"There is some evidence that static charging is not mediated by electrons and holes per se, but rather by ionic separation (a molecule splits apart into positive and negative ions, each of which resides on a different surface). Diffe... | [
"Differences in shoe materials and surfaces, frequency of contact with conducting surfaces, perhaps skin conductivity, etc."
] | [
"Posting what I think is an appropriate follow-up question:",
"Last week we had a party. We had a bunch of balloons, all the same size, all made of the same latex. They all had foil confetti stuffed into them and were then inflated. Half were inflated the normal way, by breathing into them. The other half wer... |
[
"As Earth's helium supplies dwindle in the future, is it feasible that it could be supplied as the byproduct of fusion reactors?"
] | [
false
] | Estimates place our supply of helium from 10-30 years worth, and falling fast. | [
"http://www.cbsnews.com/2100-205_162-6797764.html",
"http://digitaljournal.com/article/321439",
"http://www.guardian.co.uk/science/2012/mar/18/helium-party-balloons-squandered",
"http://www.sciencedaily.com/releases/2008/01/080102093943.htm"
] | [
"Estimates place our supply of helium from 10-30 years worth, and falling fast.",
"Citation for this, please? I've read about this, but I think it would be useful to have some context."
] | [
"yeah it could be supplied from fusion to a degree at least (depending on how much fusion is going on around the world). I wonder what the He",
" production would be though."
] |
[
"Radiation suits in Chernobyl accident?"
] | [
false
] | null | [
"What do you mean by \"radiation suit\"? You mean like a shielding suit? Because those still aren't used.",
"Anti-contamination clothing is common, and you can see it being used in the TV show. But that's not for shielding radiation, it's meant to act as a barrier between your body and the contamination in your e... | [
"A “shielding suit” is not something that actually exists, I was just using to mean some suit lined with lots of lead to stop gamma rays. Like the lead aprons you wear when you get an x-ray, but full-body, and probably thicker. That’s what I assumed you were envisioning.",
"It just seems as if most people are wal... | [
"I obviously don't know much about radiation, haha. Yes, I guess I meant the \"moon suits\" with the reflective material and air supply. Are those shielding suits? ",
"It just seems as if most people are walking around with little or no protection. On the show, and in the actual images from the accident. The mi... |
[
"Would there be higher gravity if Earth didn't spin?"
] | [
false
] | Does the Earth's spin cause an outwards centrifugal force. Theoretically if there was a planet with earth's mass that didn't spin or span slower would it have a higher gravity? I assume that if there is a difference its negligible though. | [
"Yes, the apparent gravity and your apparent weight would be a little bit greater at the equator if the earth weren't spinning (I specify the equator because the effect is not felt at the poles).",
"As for how much, you can calculate the magnitude of the centrifugal force pretty straightforwardly. Earth surface g... | [
"0.3%. That's actually a lot more than I expected. Thanks a lot for answering my question btw!"
] | [
"so, a person weighing 100kg would be 300g heavier, about a can of coke. but for something thats hundreds of tons like rockets, it would absolutely be significant!"
] |
[
"When we use wind farms and watermills to produce energy, where would the energy have been used before we \"took\" it? Are there any negative effects of this?"
] | [
false
] | [deleted] | [
"wind mills would slow the wind, but insignificantly",
"watermills/dam turbines do the same thing for rivers, slow the flow",
"I doubt a watermill would have any significant effect, a Dam though would significantly reduce the energy of the river downstream...\nDams have much more drastic upstream effects tho, b... | [
"This doesnt make sense to me. On an interval over the dam a significant portion of the rivers energy would be taken out by the turbines. Reducing energy downstream not related to water being held back initially.",
"No?"
] | [
"Part of the energy taken out is the potential energy of the difference in height from where the water enters and exists the Dam.",
"So, that will reduce the speed of the water, but if the Dam wasn't there a lot of that energy would have gone out of the water (as it does not speed up continually) in the surroundi... |
[
"How Much of Sexual Dimorphism Can be Attributed to Genetics?"
] | [
false
] | I found some data about sexual dimorphism, from wikipedia and other things, but it doesn't tell me how much of it is directly linked to genetics... How do different upbringings, lifestyles, etc. affect sexual dimorphism? | [
"Sexual dimorphism is defined as the phenotypic difference between males and females of a species. Generally, sexual dimorphism can be classified into sexual characteristics (primary or secondary), morphology (body size/shape/features), ornamentation (think brightly coloured birds) and behaviour. So of all of the a... | [
"I was especially curious about sexual dimorphism in terms of physical appearance, as it came up before and I didn't know and couldn't find out."
] | [
"I was especially curious about sexual dimorphism in terms of physical appearance, as it came up before and I didn't know and couldn't find out."
] |
[
"What happens with the CBR when you move?"
] | [
false
] | Ok, so I understand there's no such thing as absolute motion, you always need a frame of reference to determine your velocity. But the cosmic background radiation is pretty much the same in any direction you care to look, right? So assume a frame of reference in which you are currently stationary. Now start moving in any given direction. Will the CBR coming from ahead of you be blue shifted and the CBR behind you red shifted? If no, why not? And if yes, wouldn't measuring the red/blue shift of the CBR give you an absolute measure of velocity? | [
"Well, it implies there ",
" a frame of reference you could preferentially call \"at rest with respect to the universe\", but not that ",
". The typical picture you might see of the CMB (eg. ",
"https://www.esa.int/ESA_Multimedia/Images/2013/03/Planck_CMB",
") has already had the anisotropy due to our moti... | [
"Yep, it does get blue shifted in one direction and red in the other (and if you move at the speed of relativistic particles it can get weird when it gets so blue shifted that the photons are super high energy, see for example the GZK limit ",
"https://en.m.wikipedia.org/wiki/Greisen%E2%80%93Zatsepin%E2%80%93Kuzm... | [
"You can say that about anything. Me and my friend can determine our individual velocities relative to the rest frame of the earth, but that still doesn't mean the Earth's rest frame is special. You and I and the Earth and the CMBR are all things in space and we all have a rest frame, but none of those frames are s... |
[
"If I get the covid vaccine while I am breastfeeding, how long is my baby protected by my antibodies?"
] | [
false
] | [deleted] | [
"Well at least here in Germany and for the Astra Zeneca Vaccine, we have a question that reads „Are you or could you at all be pregnant or are you breastfeeding?“ if yes then that is a reason for you to actually be not vaccinated"
] | [
"That's not how immunizations really work, more of an, already immunized for full measure, would expect little to none based on this article."
] | [
"And i seriously doubt enough time has gone by to research this accurately"
] |
[
"How close in hardness do two materials need to be in order to scratch each other?"
] | [
false
] | null | [
"Thank you for asking, and for providing and explanation! That makes a lot of sense.",
"Maybe you could liase a follow up question though? It makes sense that a larger area will present some imperfections of varying hardness, but once that layer is removed, or assuming the surface area in contact to be perfectl... | [
"Thanks a lot for the explanations!"
] | [
"My attempts at reasoning through this one are that, under pressure, on the microscopic level, materials compress, becoming more dense. Does this equate to an increased hardness? I have this nagging suspicion that how close the two materials have to be is related to the force squeezing them together. I didn't st... |
[
"What would happen if we 'bled' a volcano? Would it release pressure, or would it make things worse?"
] | [
false
] | [deleted] | [
"it would completely depend on the type of volcano that you're trying to 'bleed'. If you're looking at a volcano that has a magma chamber filled with andesites and rhyolites (a very quartz rich magma) (see any of the volcanoes around the Ring of Fire\") then drilling a hole to it would be pointless as these magmas ... | [
"The ",
"Ring of Fire",
" is composed of andesitic volcanoes. These volcanoes have a very high percentage of quartz, thus making them gloopy and viscous. This means that it can create seals and build up massive amounts of pressure within a magma chamber. However, this also means that if you tried to drill a h... | [
"The ",
"Ring of Fire",
" is composed of andesitic volcanoes. These volcanoes have a very high percentage of quartz, thus making them gloopy and viscous. This means that it can create seals and build up massive amounts of pressure within a magma chamber. However, this also means that if you tried to drill a h... |
[
"what is the difference between an electron and a black hole electron?"
] | [
false
] | given that they are both treated as point particles, i'm imagining that the 'energy density' around the 'center point' of an electron is insufficient? something like that but phrased in a way that makes sense? how could one theoretically confine an electron's energy to a sufficient density? how would the interactions of such a particle differ from a normal electron? | [
"That's the whole point of the idea: that if a black hole could exist that had the same mass and charge as an electron, it might be indistinguishable from an electron.",
"The trouble is, such a black hole would be impossible given our current understanding of gravitation. Well. Not exactly impossible, but rather ... | [
"I might be mistaken, but I don't believe that a black hole of that size would evaporate by Hawking radiation. Hawking radiation works by the fact that vacuum fluctuations occur at the event horizon, with one particle being sucked into the black hole, and another being ejected out. However, because the size of th... | [
"To tell you the truth, I'm not sure.",
"To tell you more truth, I don't really understand what a naked singularity is.",
"I'm not fully versed on GR, which is a weakness of mine."
] |
[
"How do we *remember* smells?"
] | [
false
] | For example, i can tell the difference between a peruvian and an indian mango by smell? How does the brain create a point of reference for this comparison? Also, What is the mechanism of this comparison? This question can also be extended to tastes. | [
"The olfactory nerve is unique to the other sensory nerves in the fact it has direct connection with the limbic system and the hippocampus, structures involved with emotion and memory. Your other senses primarily synapse in the thalamus before extending to other areas of your brain and their connectiona with the l... | [
"to answer the question, you really have to extend it to: \"How do we remember?\" Smells in your head are just another type of information in the brain, so you remember them in a similar way to the way you remember what your car looks like, the color of flowers, the feel of cotton. it's all just sensory input"
] | [
"True! Although there is also some evidence to say that smells associated with emotional things are 'remembered' in the older, deeper brain regions, which is why the smell of home is so powerful."
] |
[
"Does your body's production of Vitamin D change depending on your dietary intake of Vitamin D?"
] | [
false
] | [deleted] | [
"That particular question either has not been addressed, or it is not documented in this summary. ",
"http://www.vitamindcouncil.org/about-vitamin-d/how-do-i-get-the-vitamin-d-my-body-needs/",
"Here:\n",
"https://en.wikipedia.org/wiki/Vitamin_D",
"\"The evidence indicates that the synthesis of vitamin D fro... | [
"inflammation/infection will also effect your dietary absorption of vit d and well as the conversion to the active hormone. "
] | [
"Nope, it all depends on your nutritional requirements. Vitamin D synthesis requires ATP, which means that it actually costs your body some energy to make. It doesn't want to do this if there is a lot of vitamin D around, so the enzymes in the pathway are inhibited by high vitamin D concentration.",
"If you take ... |
[
"How many planets have we found like earth? And how many of them are in a good distance for us?"
] | [
false
] | null | [
"The information we have about exoplanets is limited. We know roughly their size, distance from their sun, and relative density, the periodicity of their orbit, and we occasionally get spectral data from planets that happen to pass in front of their sun. However, as we have never compared our estimates to actual fi... | [
"Stuff like this really depresses me, knowing i'll probably never set a foot on another planet, let alone into another solar system.\nKnowing of all these planets out there and potential alien life and us being unable to reach out properly or even communicate, at least in my lifetime, just gives me a huge existenti... | [
"They are finding new things out all the time. The division of NASA that evaluates potential non newtonian drives still had several candidates that haven't been tested or have been inconclusive. Though they did pretty much rule out the em drive. A non newtonian drive is the way to the stars. Basically direct transl... |
[
"What is the limiting factor of putting power through a wire?"
] | [
false
] | What is the limiting factor of transmitting power safely through a wire? Is it the voltage, current, or power? If you're putting a certain amount of power through a wire, does it matter if its high-voltage/low-amps or low-voltage/high-amps? Edit: Does it matter if it is AC or DC? | [
"Voltage * Current = Power or E*I=P. If you lower the voltage, you increase the current (though a transformer lets say)... and vice versa. Power though, will always remain the same.",
"Current is the key factor for wire though. How much current that can go through a wire is determined by the resistivity of the me... | [
"If you drop voltage, then yes, current must also lower in a resistive circuit (if the resistance wasn't what changed)... but, we're talking power.",
"We're talking a perfect transformer now (no I",
" R losses). Since there is no load (like a resistance), there is no \"work\" done.",
"Take a 10:1 transformer.... | [
"Ah, I must have missed the transformer part. Was trying to imagine a load that could dictate power without simply turning off."
] |
[
"How much bacteria or virus material is in us at the height of an illness? (cell number and/or mass)"
] | [
false
] | When we are ill, what is the volume, mass, or number of cells of bacteria or viruses that is present in our bodies? Can someone make the amount of bacteria in our bodies tangible please? Thank you scientists! | [
"You need to watch this:\n",
"http://www.ted.com/talks/bonnie_bassler_on_how_bacteria_communicate.html",
"Basiclally you're 1 trillion cells. At any one time your have 10 trillion bacterial cells in or on you.",
"Most organisms are not what you think they are: being a homgenious collection of cells. "
] | [
"Let's take the example of VIH infection.\nThe number of copies of the virus in circulation varies depending on the time since the infection, but at the peak concentration (a few weeks after infection), there can be a few millions of virus per ml. \n120nm diameter, times, say 5 millions, is in volume, 0.0000005 % o... | [
"Thanks! A teacher of mine showed me this in school, but I'm referring to the specific pathogen that is causing someone to be sick."
] |
[
"Why are stomach transplants so uncommon?"
] | [
false
] | [deleted] | [
"You can, indeed, live without a stomach. IANAE on any of this, though, so I'll leave your other questions to others."
] | [
"You eat very small portions more often. They don't necessarily have to be mashed/ground, but they do have to be well-chewed. The pancreas/liver release protein-degrading enzymes/products, and they're typically sufficient, again as long as you eat small quantities at a time. And yes, the stomach does have some a... | [
"It's always a risk-benefit analysis. The stomach is not necessary for life, and on its own is generally not worth the detriment of life-long immunosuppressive therapy. But if someone were to need a liver transplant, which would save their life, and also happened to need a new stomach, that can be done (this is a... |
[
"Why does twisting a cork make it easier to pull out of a bottle?"
] | [
false
] | [deleted] | [
"Leverage. You can apply far more torque by twisting than you can do force by just pulling upwards. The length of your arm/wrist/whatever you use can amplify the force you are applying with respect to just pulling."
] | [
"Leverage. You can apply far more torque by twisting than you can do force by just pulling upwards. The length of your arm/wrist/whatever you use can amplify the force you are applying with respect to just pulling."
] | [
"Kinetic friction is less than static friction. Twisting the cork is the easiest way to get it to move, and thus to lower the frictional forces. It is then easier to pull upwards out of the bottle."
] |
[
"Why can light waves travel through space but sound waves can't?"
] | [
false
] | null | [
"Sound is a vibration of a material, and so it cannot exist where there is not a material to vibrate.",
"Light waves are electromagnetic waves; they are thing unto themselves, not the vibration of something else, and thus can exist in the vacuum of space."
] | [
"No, please no.",
"Fields are ",
" a quantum thing. Fields may be quantized, and you get a quantum field theory, but there are many classical fields: for example the electromagnetic field (aka light), or the gravitational field. Trying to find out how to quantize the gravitational field is a big thing right now... | [
"I think it's necessary to point out that the standard model is ",
" otherwise known as QFT. It is an ",
" of a QFT."
] |
[
"Is the number of colors infinite? If not, how many colors are there? Also, is there a definition of red, orange, etc. and who define this, or is it arbitrary?"
] | [
false
] | null | [
"can you divide the spectrum of light infinitely? sure. Can the Human eye distinguish between infinite gradations? no, not really.",
"You may find the results of ",
"xkcd's color survey",
" interesting."
] | [
"well we do have some nominal definitions, but they're not hard and fast rules. 635 nm is red, 530 nm is green, and 445 nm is blue. (mostly because we can make rather common lasers in these colors)"
] | [
"Color definitions are arbitrary. In fact, ",
"many languages use the same word for \"blue\" and \"green\"",
", and ",
"Homer's useage of strange colors like \"wine-dark\" seas and \"bronze\" sky",
" have led to some interesting insight into the division of the color spectrum of Ancient Greek."
] |
[
"What is unique about aloe vera that makes it so good for sunburns?"
] | [
false
] | null | [
"The abstract from this paper about wound healing: ",
"http://www.ncbi.nlm.nih.gov/pubmed?term=9562243",
"Wound healing is a fundamental response to tissue injury that results in restoration of tissue integrity. This end is achieved mainly by the synthesis of the connective tissue matrix. Collagen is the major ... | [
"I had this same question awhile ago, due to years of it being recommended by parents, friends, pedestrians....etc. However, I could find very few conclusive studies documenting it's effectiveness. It's wikipedia article addresses most parts of the controversy and cites ",
"this",
" paper that concludes aloe ve... | [
"I never even realized it was supposed to help with healing. I used to filet aloe leaves and use the jar of aloe goo on sunburns just because its cold and feels really really good on burnt skin. Never even considered that it would actually help heal anything. "
] |
[
"Can a better space telescope be built today?"
] | [
false
] | Hubble initially cost 400 million. Let's say I have one billion now. Can I build a better space telescope than Hubble or is it still the best we can build and put in space? | [
"https://secure.wikimedia.org/wikipedia/en/wiki/Very_Large_Array",
"\n",
"https://secure.wikimedia.org/wikipedia/en/wiki/Very_Small_Array",
"\n",
"https://secure.wikimedia.org/wikipedia/en/wiki/Very_Large_Telescope",
"\n",
"https://secure.wikimedia.org/wikipedia/en/wiki/Very_Long_Baseline_Array",
"\n"... | [
"We've done ",
"an IR telescope",
" and are ",
"working on another",
"."
] | [
"as pointed out theres the James Webb telescope, to replace the Hubble telescope. theres also an enormous ground based telescope that is being worked on, can't remember the name of that project though :( "
] |
[
"If there were a mass the size of an electron that doubled in size every 24 hours, how long would it take to consume the visible universe?"
] | [
false
] | null | [
"Hi Zachvehlert 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 fol... | [
"Hi Zachvehlert 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 fol... | [
"Hi Zachvehlert 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 fol... |
[
"Can someone please explain to me the concept of light cones?"
] | [
false
] | I've been getting interested in science again lately so I downloaded the kindle version of "A Brief History of Time." I've gotten as far as this part and now I'm having trouble picturing how light cones work in my head. Are we actually talking about a cone that the light from a specific light source would make as it travels outward through space and time from it's origin? Or is it more of a diagram that what would be affected by what happens at a particular event in space time? Or am I way off? | [
"The light cone is a somewhat abstract way of visualize how things are connected in time and space. The light cone simply shows how far away things can be from an event and still be causally connected as time goes by.",
"When an event occurs somewhere (event A), information about this event can be transmitted no ... | [
"The \"cone\" isn't the actual thing; it's the shape of the graph when you describe the actual thing.",
"The origin is a point, the \"now\" if you like. For every unit of time that passes, light travels a certain distance. If you talk about a year, everything more than a light year away is outside the light cone.... | [
"Here's the typical way they show it",
". Imagine that, instead of being 3 dimensional, all of space is two dimensional, and that you're standing still. The big, flat plane in the middle of the image is space at the actual present time - how everything is at a given moment. If you go up or down, the line directly... |
[
"Could astronauts in orbit for long periods be prophylactically treated with medications for osteoporosis and perhaps muscle stimulating medicines to prevent atrophy?"
] | [
false
] | null | [
"Edit: I noticed after typing this that your question is about prophylaxis. So presumably you mean before they launch. My bad. ",
"I don’t know what current practice was, but when I was in university one of the professors I worked for was working with NASA on a stimulation device to prevent osteoporosis. T... | [
"Ok, my NASA friends have got your back! ",
"Here",
" is the official NASA roadmap for research about mitigating bone loss related fracture risks, and ",
"here",
" is the specific section that discusses prevention mitigation. ",
"Regarding medication they say that since there is a very low chance of a ... | [
"That’s interesting- you thought prophylactic as in before launch.\nI thought prophylactic as in before disease sets in, but while they are in space. As in, treat them like post-menopausal women with Vitamin D and Miacalcin or alendronate."
] |
[
"I read recently that Jupiter itself is shrinking by 2cm per year. Does this mean it will eventually dissapear? How will this work?"
] | [
false
] | null | [
"Jupiter is just compressing because its getting colder. It cannot compress infinetly so it will never disappear. Infact, rigth now its only shriking at half the speed than what it did when it formed, and it will continue to slow down."
] | [
"The Sun won't expand enough to consume Jupiter. Only enough to consume Mercury, Venus, and maybe the Earth."
] | [
"And even if it did it would happen in 7 billion years, long after the sun has become a supergiant and likely destroyed Jupiter in the process."
] |
[
"I understand trigonometry and it's identities but I am having trouble understanding it intuitively. I've read and seen all the unit circle definitions and I grasp that perfectly. It's just that, I'm looking for an explanation that doesn't rely on geometry?"
] | [
false
] | [deleted] | [
"but these probably won't make things clearer for you.",
"I whole-heartedly agree with this. The whole point of sine, cosine, tangent etc are to understand circles and triangles. Why does sin(x+y)=sin(x)cos(y)+cos(x)sin(y)? Because of ",
"these triangles",
". If you separate the trig functions from circles an... | [
"but these probably won't make things clearer for you.",
"I whole-heartedly agree with this. The whole point of sine, cosine, tangent etc are to understand circles and triangles. Why does sin(x+y)=sin(x)cos(y)+cos(x)sin(y)? Because of ",
"these triangles",
". If you separate the trig functions from circles an... | [
"First, it may be useful to consider that trigonometry could exist with no other meaning than to triangles, or the unit circle. If all you wanted to do was study those, trigonometry gets you a long ways.",
"Anyways, consider a polar coordinate system. A point is defined by how far it is from the origin, which wil... |
[
"How scientifically founded is this: \"Bohm believes the reason subatomic particles are able to remain in contact with one another regardless of the distance separating them is not because they are sending some sort of mysterious signal back and forth, but because their separateness is an illusion.\""
] | [
false
] | In reference to Is there any other serious scientists that truly believe we are living in a hologram/illusion? If so why has the general science not embraced this idea yet? | [
"What? That's nonsense. Interpretations of quantum physics are both important ",
" highly scientific. Just because we might not yet have been able to find, e.g., a way to test out different interpretations of quantum mechanics doesn't make them unscientific: they still have to be able to explain what we observe i... | [
"This hologram idea is developed starting at ",
"Bohmian mechanics",
", which constitute a ",
" hidden variable model (and thus cannot be refuted by, e.g. Bell's inequality) which so far has proven to be entirely consistent with observations. It's just somewhat contrived and might fail a close shave with Occa... | [
"Does he have any math describing this connection?"
] |
[
"Dolphins use echolocation to visualize objects around them, and are able to make a wide variety of sounds. Can they reproduce the echo or sound image of an object in order to communicate it to other dolphins?"
] | [
false
] | For example, to say the word "fish", could they reproduce the sound image (or a simplified version) of a fish? | [
"No. They use language to talk with other dolphins. They don't throw their voice like to make the sound wave look like that of a ricochet because that wouldn't work. The dolphin that is looking with echolocation specifically needs to make the noise so they know precisely how long it has been since their sound was s... | [
"It's not really possible to do that. Think of sonar like a strobe flashlight in the dark. Every time it strobes, the photons bounce off the surrounding objects and return to the eye, right? For a dolphin, the 'strobe light' is the 'clicks' they make, and the 'eyes' are the sac on their forehead.",
"But having a ... | [
"I have a hard time understanding the difference between \"acoustic communication\" and language.",
"Human communication (excluding all technology) is acoustic communication, right? Or am I missing some crucial detail?",
"Edit:\nAlso excluding sign language."
] |
[
"How come light traveling across the universe/galaxy is not affected by the sources from which it was emitted?"
] | [
false
] | To provide some further insight, a photon is emitted from a star, and this star has gravity. The light from the photon is moving fast enough to escape the gravity. But if this photon comes close to a black hole, it can be warped and bent around it, or captured into it by crossing the event horizon. So we know that gravity can effect light; then would not gravity from the things behind the photon (that is, things from the point where the photon was emitted) have some kind of pull on the photon, slowing it down? I guess another way to state this is, if the event horizon of a black hole can alter the course/speed of a photon, why can't galaxies and stars 'pull' on photons and cause their speed to slow down over huge distances? | [
"Light is affected by the gravity of everything, not just black holes. Like you say, light can be deflected by gravitational fields. We notice this from starlight being bent around the sun during total solar eclipses for instance.",
"And gravitational fields also affect the energy of photons, but not by slowing t... | [
"E = mc",
" is not the full equation, and as you noticed, breaks when dealing with light which has 0 mass, implying all light has 0 energy. The actual equation is ",
"this one",
".",
"And yes, there's actually 3 different kinds (sources) of redshift. Cosmological is from the expanding universe and is usuall... | [
"E=mc",
" has nothing to do with this. The energy of a photon is E=hf. The universe simply demands that things without rest mass move at the speed of light. The photon must lose energy as it travels up the gravity well, but it can’t slow down, so instead the frequency is reduced (wavelength is increased).",
"Yo... |
[
"What do we mean when we say one charge is negative and the other is positive, and what is the difference between the two?"
] | [
false
] | Do we know what charges actually are? Any further expounding on electricity would be welcome as well! | [
"Charge is just a property, like mass, that some particles have. It's a conserved quantity. That is, for a closed system, the total amount of charge it contains doesn't change. Thus charge can only be created or destroyed in pairs of opposites. There's not much more to be said about ",
" than that.",
"Now t... | [
"Charge describes the coupling of a particle to the photon (electromagnetic) field. It is a fundamental property of a particle, and is irreducible in the sense that there is nothing underlying the electromagnetic interaction: it just ",
". What we call \"electricity\" is merely the motion of charges, and what we ... | [
"First, charge being positive or negative charges is an arbitrary convention created by Ben Franklin back in the day. We know that like charges repel, unlike charges attract and that the strength of these forces is proportional to the product of the amount of charges. By assigning one type as positive numbers; on... |
[
"How does energy have weight?"
] | [
false
] | Say in the compressed spring example, the spring gains more (potential) energy. And from E=mc2 the spring has more mass and therefore has more weight, assuming earth gravitational field. How can I imagine this Energy as having more weight? | [
"Well, first realize that the majority of the mass in the uncompressed string is also due to energy, namely the binding energy in the strong force that keeps the baryons and atoms together. The higgs mechanism gives mass as well, but not nearly as much as the binding energy.",
"Realize that energy is what bends s... | [
"I Apologise beforehand if I don't word my questions clearly enough, it's something I'm working on. ",
"Say E=mc",
" we can see that Energy = Mass. So if I boiled a bowl of water I am adding energy to it. Based on this equation the water would have more mass! Well where did the mass come from?? Well the energy ... | [
"I Apologise beforehand if I don't word my questions clearly enough, it's something I'm working on. ",
"Say E=mc",
" we can see that Energy = Mass. So if I boiled a bowl of water I am adding energy to it. Based on this equation the water would have more mass! Well where did the mass come from?? Well the energy ... |
[
"It is theorized that chloroplasts and mitochondria were once their own organisms. If we took them out of their host cells, could they maintain life as their own free-living organism today?"
] | [
false
] | [deleted] | [
"To add to what others have said here, plastids (mitochondria and chloroplasts) once had complete genomes, but over time most of the genes that started out in the plastids have been moved into the nuclear genome. For a sense of scale, mitochondria have about 1,000 proteins (gene products) working inside of them, b... | [
"Yes to both. The mitochondria (and the chloroplast) have their own, unique DNA. And the genes that those genomes contain can vary between species (as different evolutionary linage have moved different genes from the plastid to the nucleus. This is part of the evidence that supports the endosymbiont theory).",
... | [
"No, that wouldn't work. As you say, it is theorized that mitochondria and chloroblasts were individual organisms and that they formed a symbiosis with other cells. The fact that they still contain fragments of their own DNA supports this theory.",
"Through evolution, these organisms have come to specialize in a ... |
[
"How does gravity bend space in 3 dimensions? The usual depictions shows only 2. (Related, what \"shape\" is the universe?)"
] | [
false
] | Let's see if this makes any sense: Another redditor made this about the universe being "planar", and it reminded of how most depictions of gravity look something like , which I assume is quite simplified. But if everything is 3D, how should this look as opposed to these 2D depictions? How planar really is the universe? I tend think of the universe as a giant dark room with stars/planets/galaxies etc. floating all over in three-dimensional space. Is that totally incorrect? But then thinking of it as something planar with things "sitting" on top doesn't seem right at all. | [
"We have to very careful here—we have two separate concepts: Spatial curvature and spacetime curvature. Spacetime curvature tells you about the gravitational sources present, but ",
"spatial curvature, called k,",
" tells you about the density of the universe. When you seek pictures showing sphere, saddles and ... | [
"Say you're trying to make a map of the earth. The problem is that paper is flat and the surface of the earth is curved. There's two basic ways to do it. One way, is to have a warped map. Or rather, multiple warped maps, since one map will always be missing at least one point. For example, most maps you see don't c... | [
"The comment about the universe being planar was basically saying that if you walk in one direction you don't end up coming back around to where you started. ",
"The 2D depictions of gravity bending space are just doing the best they can... The best way to \"depict it in 3D\" would be ",
"something like this",
... |
[
"Do photon transistors exist?"
] | [
false
] | And if they do, what would they look like physically, what media would they use, like current ICs use silicon? Are light-based or photonic computers a possibility? Would they be significantly more efficient than our current electronic ones? | [
"They do indeed:",
"https://en.wikipedia.org/wiki/Optical_transistor",
"Photonics aren't at all my thing, but I understand that a generic issue with photonics is that the wavelength of light is quite large relative to an electron's de Broglie wavelength and thus any computing devices based on photonics must be ... | [
"All-optical switching is achieved by employing materials with nonlinear optical properties. Certain materials have a refractive index that changes with the intensity of incident light: you can make an optical transistor by using a light source to modulate the refractive index, and another source so modulate the si... | [
"Certain materials have a refractive index that changes with the intensity of incident light",
"I always thought that the kerr effect happens in all materials in high enough intensities (although some have it stronger than others). "
] |
[
"What method do they use to date wooden artifacts?"
] | [
false
] | I was wondering, can they use carbon dating, or is that just for animals that have consumed carbon-14. And is tree ring dating pretty much useless due to the fact that the wood would have been shaped (pardon the pun). | [
"Yup, we use tree rings! It isn't immediately obvious how, given that tree rings appear to be useful only if we have an entire cross-section from a tree's birth to its death, but that's a shallow assumption. Trees from the same forest tend to develop similar ring patterns, since their living conditions are identica... | [
"Cheers mate"
] | [
"All living organisms take in carbon-14. Including plants.",
"So carbon dating wood is absolutely a possibility. However, there are problems with dating wood that have to be accounted for.",
"Trees-- as most everyone knows-- grow by adding new growth annually, and this takes the form of \"rings\" if the tree is... |
[
"I've heard that distilled water leeches minerals from the body. Is this true or supported with any evidence?"
] | [
false
] | It seems to be somewhat of a stretch being made with regards to the claim. I thought that with osmosis, even if the claim were true, that this "pure" water would be somewhat absorbed even more into the body. | [
"As far as I know, there isn't any published scientific research supporting the idea that drinking distilled water (as opposed to hard water) significantly affects the levels of minerals or the levels of mineral absorption/secretion in a person.",
"It has been ",
"speculated that because some non-distilled drin... | [
"I'm sort of skeptical of this idea, specifically this part as it relates to the OP's question:",
"The higher the inorganic content is in a per million count, the less effectively water transmits organic minerals to tissue sites.",
"Do you know where this idea comes from? I've seen it elsewhere on the internet... | [
"It seems to be just the opposite",
". This definitely isn't a scholarly resource, but they suggest that it increases mineral absorption rates. Distilled water has reduced inorganic mineral content (these are bad, linked to \"a wide array of degenerative diseases\"). Their absence encourages the absorption of ... |
[
"For the physicists of AskScience! A mathematical question on Energy-Displacement Graphs (for the experts/brave)"
] | [
false
] | [deleted] | [
"This may not be ",
" definitive answer, but here's how I see it. You're integrate kinetic energy minus potential energy from one point to another (those points are fairly arbitrary; you've set it to be where the two are equal, but that can be redefined by resetting the zero point of the potential energy. So let'... | [
"I found this really helpful, thank you so much"
] | [
"Well, it's close to the concept of ",
"action",
", and in specific, the ",
"Lagrangian",
" or ",
"Hamiltonian",
" formalisms of physics. I mean not your area thing, but I think if that kind of question interests you, learning \"advanced\" classical mechanics (Lagrangian and Hamiltonian; ie mechanics pa... |
[
"Why can't we control our involuntary muscles?"
] | [
false
] | Something that I've always wondered about. Why can't we control our heart beat, our digestion, or any number of involuntary processes? | [
"Same reason you can't turn on the garbage disposal with the bathroom light switch; the hookup's not there. ",
"You can train yourself to affect your heart rate, though; scare yourself, calm yourself, etc, but that's more indirect."
] | [
"From an evolutionary perspective its because they are safer if they are automatic. Even humans didn't properly understand the most basic physiology until a few hundred years ago. ",
"The diaphragm is an interesting example of a voluntary muscle with an involuntary override."
] | [
"Control of your heartbeat is incredibly useful in stressful situations (and when you really want to upset your nurses in the hospital). "
] |
[
"Can we soon look forward to a period during which the ocean provides more and more food and raw materials for the exploding world population of humans?"
] | [
false
] | [deleted] | [
"We are really messing up the oceans. No amount of new technology will allow us to extract more from 99% of the already over exploited populations (we have sort of hit our peak, but even if it did advance what would be left to fish?). Of those that are doing well its usually because they are too far out (meaning th... | [
"No. the human population has exceeded the Earths carrying capacity. Energy budgets of aquaculture are likey much less efficient than natural systems. The increased use of shrimp farms and the like will very likely hasten the destruction of marine food chains. Increased release of nitrate and phosphate into the... | [
"If you can provide studies that support what you say no one will have to downvote you."
] |
[
"What wavelength range is cherenkov radiation?"
] | [
false
] | [deleted] | [
"It depends of the velocity of the particle and the properties of the medium in which the Cherenkov radiation is being emitted. The ",
"frank-tamm formula",
" can be used to calculate the energy radiated at a particular frequency."
] | [
"So use the relevant properties of your medium (which I'm assuming is water) and the average velocity of your particles. Put everything into Mathematica (or whatever program you typically use) and have it graph the spectrum."
] | [
"Specifically, I'm measuring cherenkov radiation from a research reactor in a pool of water. "
] |
[
"What are the conditions needed for Fossils to form? Can we replicate those conditions?"
] | [
false
] | null | [
"Fossils can be made in several different ways, but in most cases something needs to cover the remains and prevent them from being broken down by the passage of time. Things like tar and mud have been really good for this and it’s similar with small insects and amber. If you coated something recently in epoxy and p... | [
"Say we bury a plastinated creature, it would take a white before it gets destroyed right?"
] | [
"For a fossil to form you need to have an organism not only die but be isolated in an inaerobic enviornment quickly after death (Which is why tar pits, landslides, and such things are good at doing that) and then hope that itll stay like that for a while. And while that is easy to replicate, there are easier method... |
[
"Why is there a desert on the Arabian peninsula?"
] | [
false
] | The Arabian peninsula is surrounded on water on 3 sides and has mountain ranges that could catch precipitation coming from the red sea, Persian gulf and Arabian sea. I know that its an extension of the Sahara but shouldn't there be areas on the peninsula that do have good amounts of precipitation? | [
"The bodies of water it's surrounded by are not large enough to have meaningful effects from trade winds, or cyclic winds that carry water from other climate zones and dump it there.",
"Coastal mountain ranges typically capture precipitation that trade winds pick up as evaporate that's accumulated as they travel ... | [
"The mountains do receive greater rainfall than the rest of the peninsula.",
"The area gets very little rain, outside of the rainy reason; underground aquifers capture most of it, and it's very hot besides. The areas at elevation, near mountains and near the coast do\nproduce some verdant land, but these mountain... | [
"Chances are the Persian Gulf and the Arabian Sea are deserts themselves, meaning very low rainfall. I remember reading quite a while ago that the desert conditions that affect Los Angeles extend pretty far out into the Pacific ocean."
] |
[
"What could have caused a tick to detach after only and hour or two?"
] | [
false
] | null | [
"We can't comment on personal anecdotes / isolated events without resorting to speculation which we always try to avoid."
] | [
"Any suggestion as to where I might go to find relevant information? Everything I’ve been able to find suggests this is not a usual occurrence and I’ve become extremely curious"
] | [
"Unfortunately no, but maybe the folks at ",
"/r/findareddit",
" can help find the right place to ask."
] |
[
"Science, please tell me this is complete bullshit."
] | [
false
] | crosspost from by BeerSensor (who does not agree with the article) | [
"Total, unadulterated BS.",
"Edit: I was going to add in here a more measured discussion, but on re-review, literally every sentence in the third and fourth paragraph is utter bullshit. Not one fact is correct. It's difficult to even explain how completely and thoroughly ludicrous it is. In some ways, it's rea... | [
"Just for fun, I'm going to go through and point out each piece of BS that I come across. I'll start with paragraph three, since the first two just set up the question.",
"Wine cells: Wine is not an organism although I suppose there are probably living things in wines. The living things do not constitute the subs... | [
"I thought I had chronic diarrhea. Turns out that I had been working in the magnet factory too long. Just had to realign my poop cells."
] |
[
"How are primes calculated for RSA?"
] | [
false
] | Why is it hard to calculate the factors of n, for a 1024-bit key but easier to calculate factors for 1024-bit p and q for a 2048-bit n? Is it because calculating primes is easier than calculating numbers with exactly 4 factors (including 1 and the number itself)? | [
"This answer is good. But I want to expand on two aspects.",
"It's just \"get random number\", \"check if large enough\" and \"check if prime\" untill you have 2 suitable primes.",
"One thing worth emphasizing is that you really need to go back to get a random number each time you loop. Some people think you ca... | [
"In one direction you need two primes, which can",
"It's just \"get random number\", \"check if large enough\" and \"check if prime\" untill you have 2 suitable primes.",
"In the other direction you need to more or less check ",
" primes between 10",
" and 10",
" - 1, so π(10",
" - 1) - π(10",
" ), or... | [
"It's just \"get random number\", \"check if large enough\" and \"check if prime\" untill you have 2 suitable primes.",
"I would also point out that the naive \"check if prime\" step where you try all factors up to the square root would be pretty slow in practice. ",
"Instead, typically a probabilistic primalit... |
[
"Is the sense of understanding of a 3 year old fully developed?"
] | [
false
] | null | [
"What does \"sense of understanding\" mean?"
] | [
"If they really comprehend what I'm saiyng. Like sometime she say \"I want story before bed!\" mildly crying and I tell her \"if you continue you won't have a story\" and she say \"I WANT STORY!!\" then Throw a fit or cry, which make her unable to have story."
] | [
"If you mean something like causal reasoning (how one thing causes another) or deductive reasoning (if p then q, p, therefore q), both of these continue to develop with large changes occurring around the age of 4"
] |
[
"How were maps made accurate before satellites were invented?"
] | [
false
] | null | [
"Trigonometry. ",
"Measure the distance and angle from one place to another then measure the angle to another point from those two and you know exactly where each point is relative to one another. Continue across an area and you have a map. "
] | [
"Well, yes. Even today it's mostly a lot of trigonometry - or more specifically, triangulation. The GPS works on the principle of measuring your distance from three known points. These ",
"tachymeters",
" you see used in geodesy are basically extremely precise yardsticks used in tandem with a compass to determi... | [
"Early cartographers did it the same way that we do in modern times. By using simple geometry. Instead of interferometry and satellites to measure distances/heights and angles, they were forced to use yardsticks and shadows, which made the maps look a little ",
"off",
" on large scales, but the general idea is ... |
[
"Why are there six types of quarks instead of two?"
] | [
false
] | [deleted] | [
"Yeah, that. In particle physics, a decay is a process in which a particle changes its identity, or actually ",
" into some other particle(s). It's not a case of a particle breaking apart into constituents. ",
"Outside of particle physics, some kinds of decays do involve something breaking apart into its consti... | [
"Yeah, that. In particle physics, a decay is a process in which a particle changes its identity, or actually ",
" into some other particle(s). It's not a case of a particle breaking apart into constituents. ",
"Outside of particle physics, some kinds of decays do involve something breaking apart into its consti... | [
"It's because there are a lot of phenomena that were first discovered experimentally, and looked (almost) exactly like one thing at the time, but then later on, when the theoretical explanation was worked out, it became clear that they were something else entirely. E.g. elementary particle decays looked just like r... |
[
"If you fly from the South Pole to Quito, Ecuador, where does the ~460 m/s rotational speed come from?"
] | [
false
] | You go from 0 speed relative to the center of Earth to having a horizontal speed of around 460 m/s near the equator. Where does this come from when flying? | [
"The aircraft will steer a tiny bit to the right on average. As seen by the aircraft, the Coriolis force makes it deviate to the left. Countering that (to fly straight on a map) makes it keep up with the rotation of Earth."
] | [
"The air induces a drift just like an ocean current induces a drift on a boat. At each location along the path, you'll be flying through air which is in motion relative to a fixed coordinate system. The further north you go, the higher the average speed of the air, i.e. the air near Quito will on average be movin... | [
"A rocket starting from the pole that doesn't care about the rotation will end up crossing the equator with no velocity along the equator in an inertial reference frame, i.e. it will move west as seen from the ground."
] |
[
"When you drop a rock into a pool of water, is there a way to predict the pitch of the sound that is made?"
] | [
false
] | null | [
"Some work to simulate similar effects... ",
"https://youtu.be/On4ODNwJ424"
] | [
"Everything has something to do with quantum mechanics doesn't it ? And i do know that the simple act of observation changes the way \"something\" behaves ;)"
] | [
"Ok, thanks."
] |
[
"Rubbing alcohol or hydrogen peroxide?"
] | [
false
] | I understand that this is not the place for medical advice but is there is a difference between the two or are they equally efficacious in terms of their aseptic properties? Or is one used over the other in certain circumstances? | [
"Hydrogen peroxide is an inferior antiseptic(an anti-microbial used on skin or mucus membranes) because tissue catalases can break it down into O2 and H2O. It can be used as a disinfectant (cleaning surfaces), however.",
"Alcohols are better because they are not broken down by enzymes as readily as hydrogen pero... | [
"Good info - one correction: it's 15 PSI, or lb/in",
" , not lb/ft",
" . For reference, 15 lb/ft",
" is a paltry 0.1 PSI."
] | [
"I used the wrods antiseptic and disinfectant separately because they are specific medical terminology which refer to different things. Antiseptics are antimicrobials that are applied to human skin or mucus membranes. Disinfectants are antimicrobials that are applied to non-human surfaces, such as medical instrum... |
[
"Why does both heating and cooling my house dry out the air?"
] | [
false
] | null | [
"With very few exceptions, air has a certain level of water vapor in it, which is what we refer to as humidity. Air can only hold so much water vapor in it until it is completely saturated, and this is what we mean when we say the (relative) humidity is 40%: currently, the air has 40% of the maximum amount of vapo... | [
"In a properly sealed gas heater, the combustion gases pass through the heat exchanger and out of the flue, never interacting with the inside air."
] | [
"This is why I like cooking with gas. The combustion products from a gas cookstove stay in the house and help with the RH."
] |
[
"Would space elevators have opposite \"gravity\" at the top due to centrifugal force?"
] | [
false
] | I know its not actual gravity, but it was hard to phrase the question without using the word like that. I can provide a diagram if needed. | [
"No and yes. In a sense, you have this \"opposite gravity\" while on earth's surface due to the fact that the earth is a rotating reference frame.",
"Space elevators are geosynchronous--they don't move around while on the surface of the earth--meaning that the weightlessness we typically attribute to objects in o... | [
"depends on what you mean by the top. You'd have gravity pulling downwards, and a centrifugal force pulling upwards (ignoring other effects).",
"m w^2 r - G Me m/r^2 = Fnet = 0",
"therefore r = 0 or r = G Me /w^3 (the latter being geosynchronous orbit)",
"r larger than this, have a dominant centrifugal t... | [
"No, the top of the elevator would only be moving a little faster than the earths rotation, around 1000mph, to overcome gravity it would have to move around 17000 mph. Since the elevator is connected to the ground, this isn't possible.\nYou're thinking of the elevator like a rotating space station, think of it mor... |
[
"What does empty space on a HDD consist of?"
] | [
false
] | [deleted] | [
"It doesn't matter, and in cases where it's space that formerly held contents it will depend on the former contents. More important is the file table that tracks where things are stored on the drive. Places where things aren't stored simply aren't assigned to a particular file."
] | [
"There are certain hard coded regions of a hard drive which contain metadata about how the drive is used. This is just a standard, or convention, which enables drives to be used effectively. The first information is the partition table, and this tells the operating system which different chunks of the physical hard... | [
"This is how programs like ",
"Recuva",
" work. They read the raw data still on the drive, ignoring the FAT."
] |
[
"Using Liquid Breathing, or Total Liquid Ventilation (TLV), for SCUBA diving"
] | [
false
] | Hi! I'm an avid scuba diver and a student interested in resuscitation science. I learned about liquid breathing or "liquid ice", as the researcher I talked to called it. His team is developing TLV that can induce therapeutic hypothermia during emergencies. The wiki mentions the possibility of using it in diving. There are several gas mixtures scuba divers use. The most common, of course, is air. A lot of advanced divers use nitrox to reduce decompression illness. Trimix is the most technical (and expensive!) one. Liquid breathing seems to trump them all. So my questions are 1) what do you think of the use of liquid breathing in non-medical situations, 2) what would be some pros and cons, and 3) when would it be most appropriate to use? Thanks in advance! | [
"I think you're talking about Perfluorocarbons (PFCs), which can dissolve large quantities of oxygen into solution. It has also been looked at as a potential synthetic blood for blood transfusions.",
"A couple of things that have been noted here but should be explained.",
"First, one of the largest problems wit... | [
"My cousin is a deep sea under water welder and he says that although such liquids exist (like the ones from the movie The Abyss) the process of removing them from your lungs and reintroducing air is currently not feasible; if this problem could be solved it may be useful in deep sea diving situations, but I don't ... | [
"Flushing the liquid from your lungs. "
] |
[
"Light cannot escape the gravitational pull of a black hole. So where does the light go?"
] | [
false
] | I mean, why is the black hole not lit up when the light gets "absorbed" | [
"Fun fact: If you were orbiting a black hole, and say you were invincible,the gravitational pull of said hole would be so strong that light would orbit, enabling you the ability to look forward and see the back of your head."
] | [
"When dealing with fictional things that ignore the laws of physics, you may find it hard to explain them through laws of physics."
] | [
"This is a short and highly informative video on what might happen when you travel into a black hole- I recommend you take a look.",
"http://www.youtube.com/watch?v=eI9CvipHl_c"
] |
[
"Why don't we use microwaves for heating the water in our household water heaters?"
] | [
false
] | [deleted] | [
"It's rather unnecessary and more costly. ",
"Microwaves are not a better or faster way to heat water compared to conduction. The reason they cook food faster than an oven is because the radiation causes dielectric heating in the food, rather than heating a metal element which then through some air gap heats the ... | [
"It would probably be a little less efficient, and would use a lot more complex equipment than a simple resistive electric heater.",
"An ordinary electric heater is actually very nearly 100% efficient: if you have a coil of wire immersed in water, pretty much all of the electrical energy expended in the coil is t... | [
"Just to expand on heat pumps, it's \"efficiency\"* is called Coefficient of Performance (COP), which is how much heat you can move for each unit of energy you put in, and it's necessarily better than 1 in theory. ",
"https://en.wikipedia.org/wiki/Heat_pump#Coefficient_of_performance_.28COP.29_and_lift",
"You c... |
[
"Does it make sense to wash dishes with the bubbles because \"that's where the soap is?\""
] | [
false
] | I'm man enough to admit there's no 6-year old behind this question, just me. I just won't admit it in the title. <ahem> | [
"This is outside of my panel expertise, but I spent a summer working for a major consumer products company in their soap areas.",
"The primary reason that consumer soap lathers (makes bubbles) is because consumers are conditioned to believe that if the soap doesn't lather, then it isn't cleaning anything. There a... | [
"I knew water it a fairly good cleaner compared to other liquids, and that adding soap made it 'wetter,' but I was never sure if the suds were a super-soapy zone, or just a secondary indicator of a sink full of sufficiently-soapy water. Thanks."
] | [
"This is a great answer. So you're saying, then, that there's no benefit to liquid hand soap that foams out of the bottle? it's as shameless as Selsun Blue (\"it tingles so I know it's working\") ?",
"Which, incidentally, is a product that deserves a good deal more mockery than my google search has turned up. I... |
[
"Why don't we purify saltwater using the solar still concept on a large scale?"
] | [
false
] | The drought in Cali is what got me thinking. I picture something like this: a stream of saltwater in a trough surrounded by a transparent pipe. Sun evaporates the sea water, water condenses on roof of pipe then flows to the bottom, creating a stream of clean drinking water. What am I missing? Is it cheaper to do it another way, would this not work? | [
"To get any reasonable flow of water you need a massive area and you need to cool the condensation surface. When you say it condenses on the roof of the pipe, where does that heat go and how fast is that heat transferred? In many of the places where you'd want to try this type of desalination the ambient temperatur... | [
"ramk13 has explained it well, but I would like to offer an alternative prospective.",
"What you are describing--evaporating seawater via solar power to obtain unsalted water--is essentially how cloud forms and how rain works. In another word, the nature is already doing the purification for you. By controlling t... | [
"One part that you are missing is what you do with the remaining salt-slush (brine). This salt-slush isn't safe for consumption, and must be disposed of, or excess energy needs to be utilized to further dehydrate it to make it a consumable. Do you dump the salt-slush back from the source where you obtained it? cr... |
[
"What makes the molecules in an object stick together?"
] | [
false
] | This is probably pretty basic science, but why do molecules in a solid stick together rather than fall apart from each other like sand? | [
"It depends on the solid. In ",
" materials, you essentially don't have individual molecules anymore, rather the molecules clump together in a giant network with the same kinds of bonds as you have within the molecule. Effectively, a crystal is a single giant molecule in a repeated pattern. (E.g. a salt molecule,... | [
"Atoms have a positivity charged nucleus surrounded by negative electrons. The total charge of an atom is zero, but the electrons aren't always evenly spread on the surface of the atom (or molecule), leading to areas with different charge. If the kinetic energy is low enough, these charges cause them to stick toget... | [
"That's a perfectly okay, albeit simplified, description of Keesom forces, which is one of the most significant intermolecular forces. "
] |
[
"Can someone please explain why dead weight appears to feel heavier than standard weight?"
] | [
false
] | [deleted] | [
"It's a matter of the clumsiness of handling a floppy body instead of a rigid weight.",
"If you were to try to move a 150 pound cooler, you would have an easier time with that than moving a 150 pound body simply because the cooler is both compact and rigid in comparison. "
] | [
"To elaborate on this: Your arm muscles obviously have to exert the same amount of force to hold the person up. But that's not all that carrying someone involves; you ",
" have to use stabilizing muscles to keep them centered. If they're conscious they will instinctively do some of this work, and if they're not i... | [
"\"Dead Weight\" is simply the unrelieved weight of a thing. A conscious person would make some effort to support themselves, ideally, by placing their arms around your neck or something to that effect. But a conscious person who simply went limp would still be considered \"Dead Weight\". ",
"There is no literal ... |
[
"Why do nucleons lose mass when they bind into atoms?"
] | [
false
] | null | [
"Because of the nuclear force, they go into a more energetically stable configuration, a lower potential energy, and release that potential energy in the form of electromagnetic and kinetic energy, similarly to an exothermic chemical reaction. It is difficult to get more specific than that, since the nuclear force ... | [
"When they bind into stable atoms, they release energy in the form of heat and electromagnetic radiation. E = mc",
" of course. E = mc",
" for chemical reactions too, just like with nuclear reactions, it's just that nuclear reactions involve a lot more energy so you can actually measure the mass change easily... | [
"I know that mass and energy are interchangeable in this case, I could as well phrase the title \"why do nucleons have to lose mass/energy to form a stable atom\". "
] |
[
"Is the metric expansion of space occurring in some form at all scales, or only for astronomical distances?"
] | [
false
] | null | [
"The expansion does happen at all scales. The rate of the expansion is measured at approximately 74 kilometers per second per ",
". A megaparsec is a little over 3 million light years, or about 20 thousand trillion kilometers! So shrinking that down to a human reasonable scale that's an expansion rate of about... | [
"This is not correct. Metric expansion of space does not happen at all where gravity is significant. It's not like expansion is happening everywhere but gravity keeps matter together, expansion of space can only happen where gravity is insignificant. ",
"/u/shavera",
" has written a couple of ",
" good commen... | [
"Not only is gravity strong enough on this local scale, but on the scale of galaxy clusters its still strong enough to keep the galaxies in a given cluster bound together."
] |
[
"In semiconductor chip manufacturing, how do they move the wafer or the stencil with nanometer accuracy for the many layers?"
] | [
false
] | [deleted] | [
"I know that some of them use piezoelectric actuators. For example:",
"http://www.pi-usa.us/products/Nanopositioning_Scanning_Stages/Nanopositioning_Stage_Basics_Piezo-Driven_Nano-Positioning.php"
] | [
"Right, I have the same experience when I did labwork. The first rough movements are done with motor actuators. The small adjustments with piezoelectric actuators. I think piezoelectric actuators are the only ones reliable enough at those tiny distances."
] | [
"The same way they align components onto circuit boards, actually. There's a 1,000,000x size difference but despite that the marks can even look relatively similar. Here's some for ",
"MEMs",
", which are still 100x larger than next generation transistors but pretty much the same principles.",
"The wafers a... |
[
"What happens when T-Cells or B-Cells are in the blood for too long?"
] | [
false
] | We only really use them when we're infected with something, right? So, I imagine that they get deployed and leave after the job gets done....but what happens if the just chill in the blood? | [
"Most of them usually don't, they chill in the lymph nodes. In case of infections, the relevant ones multiply and get deployed to the blood stream to reach the infected tissue faster. Catching activated T- or B-cells in the blood is seen as a clinical sign for chronic infection or an autoimmune disease and should b... | [
"This is absolutely not true. Healthy immunocompetent adults have 1-4 ",
" T or B cells per mL of bood."
] | [
"This is absolutely not true. Healthy immunocompetent adults have 1-4 ",
" T or B cells per mL of bood."
] |
[
"How does soap work?"
] | [
false
] | I'm guessing that there is a part of soap that is soluble in water, and another part that is soluble in oil. That's what I assume; does anyone know what really goes on? | [
"Yup. Detergents are amphipathic: they have hydrophilic (interacts with water) and hydrophobic (does not interact with water, but does with oils/greases) regions which allows them to interact with both water and water-insoluble compounds. This lets them break up bits of grease into water-soluble structures."
] | [
"As an expert, I endorse this answer and encourage the OP to use Google."
] | [
"More specifically, they have a ",
" oily/hydrophobic region (hence volume), and typically ",
"such that they forms ",
"micelles",
" in aqueous solutions (see article for pretty pics). These micelles are what encapsulates the grease.",
"Israelchivili"
] |
[
"Any more recent developments in the theory that the universe isn't expanding more and more rapidly, but that time, itself, is slowing down?"
] | [
false
] | [deleted] | [
"How could we perceive time slowing down? I assume that slowing time will necessarily slow the chemical reactions in our bodies, and thus slow our thoughts. Thus, we would never perceive time slowing down, since our thoughts are still in sync with everything else.",
"For that matter, how could we measure time slo... | [
"We would get the same result because the slowing would affect our measurement, the particles being measured and our perception equally. "
] | [
"Consider two locations A and B, with time \"faster\" at B than A. Assume we have two identical clocks. At either location A or B, the clocks tick at the same rate, so there's nothing amiss. But if we separate the clocks to A and B for some time, and then bring them back together, we would see that the clock at B i... |
[
"How much do stars expand when going supernova?"
] | [
false
] | [deleted] | [
"NaN%",
"In the case of core-collapse supernovae, the outer layers are ejected at up to a few percent c. The nebula is in no way gravitationally bound, and will just expand and disperse over time. One could perhaps compare it to the difficulties in describing the size of a smoke plume.",
"For Type Ia supernovae... | [
"The sun can't go supernova, so this would require some rather silly assumptions to cause one. If it's anything like a normal supernovae, see my previous answer."
] | [
"That explains why I couldn't get an awnser. What about if specifically our sun went supernova? Thanks for the response btw!"
] |
[
"Are reptiles as prone to over-consumption of resources when compared to mammals?"
] | [
false
] | I read this and wondered if reptiles, such as the Komodo dragon, could be at risk for a massive die-off for similar reasons, such as having no natural predators. If that comic were about reptiles and not mammals, would it still be the same outcome? Could reptiles manage their food source in different ways, such as not having to eat nearly as much as a similar sized mammal, or would they become fat and lazy to the point they eventually overshoot their limit? | [
"link appears broken"
] | [
"I think the big difference here is that these were primary consumers. Lizards such as ",
" are opportunistic scavengers and carnivores. Once you have predator-prey relationships, a dynamic cycle is established that keeps both populations in check.",
"Why dont giant (herbivorous) tortoises, like on the Galapago... | [
"My apologies. I've fixed the link."
] |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...". Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists. Please only answer a posted question if you are an expert in the field. . In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for . If you would like to become a member of the AskScience panel, . Past AskAnythingWednesday posts . Ask away! | [
"You would test for antibodies to the virus to see if the vaccine worked.\nMost of the vaccines won't grant you immunity outright. Most people may end up more or less immune, but many people will only end up resistant to the virus and can still contract COVID. Life won't be going back to normal for at least another... | [
"Hi, I was wondering have Koch's Postulates been satisfied (in full) for every disease we have identified? What is accepted medically as 'satisfied'? ",
"Further, do we even need to satisfy all of Koch's Postulates to prove a causitive link between a pathogen and a disease being caused and if not, why not? Do asy... | [
"Hi.",
"How was determined the daily amount of vitamins for a person? ",
"Some sources say that we need to take vitamins, some do not. But even if the deficit is prooven by the tests (which is the question in itself: how do we know how much should be there?), there is a dosage of the said vitamin. Where does it... |
[
"Can humans adapt and survive with Martian gravity?"
] | [
false
] | Let's imagine a future Martian colony... People who aren't interested in a return trip to Earth. They would lose bone density on Mars, but would that be okay if they stayed on Mars? If they traveled to Earth for the first time, would they be able to build their body up to function on Earth? I'm writing a scifi screenplay for a class and I want to remain as true to science as possible. | [
"They would lose muscle mass as well since everything weighs less. If they tried to retain earth-like muscle mass/bone density by working out and such yes (the astronauts on the ISS do this). They could also gradually get their bodies used to the lower gravity using the same method. If they decided to instantly go... | [
"From 9877 A.D., we note the following in our Encyclopedia Solsystica:",
"exoskeleton: \n People from low gravity worlds have great difficulty moving about on worlds of higher gravity. Such a low gravity worlder can feel that his or her body weighs two to ten times what it should on a higher gravity world.\n ... | [
"Yes, but they would loose a lot of muscle mass. Also, going back to earth after an extended period of time could be dangerous unless they exercised frequently."
] |
[
"The Pauli-Exclusion Principle doesn't apply to Bosons because muliple Bosons can occupy the same quantum state. Does this mean that the Pauli-Exclusion principle doesn't appl particles with spin numbers that are integers?"
] | [
false
] | null | [
"but what about particles with spin numbers that are integers?",
"Those are bosons."
] | [
"A boson, yes."
] | [
"So any particle with a whole spin number is considered a bison?"
] |
[
"If I add nicotine to the water of my hydroponic tomatoes, will the tomatoes have nicotine?"
] | [
false
] | [deleted] | [
"This is a great question.",
"The quick answer is no. The plant takes in nutrients (chemicals it has a use for) and breaks them down to smaller units that it then uses to build plant structures. At first guess I would say it would have no effect and certainly not be in the plant.",
"In the case of nicotine, "... | [
"So hypothetically, one could breed for nicotine content and eventually arrive at tomacco organically?"
] | [
"Tomatoes have small but significant amounts of nicotine present naturally.",
"http://www.nejm.org/doi/full/10.1056/NEJM199308053290619"
] |
[
"When throwing stuff, does our brain actually try to calculate how hard it has to throw for the item to land at the desired point? Or does it just estimate based on experience?"
] | [
false
] | I am just wondering wether the brain is secretly awesome at physics or just good at weight / strength estimation. | [
"Well there are no citations nor any reference to any work done on how the brain does this kind of processing. So that \"answer\" just knds of reiterates your questions with the word evolution thrown in. "
] | [
"Our brains are wonderfully equipped to handle classical physics calculations on the fly. ",
"How? Or are you just assuming the brain implements some kind of proxy newtonian mechanics?"
] | [
"Our brains are wonderfully equipped to handle classical physics calculations on the fly. ",
"How? Or are you just assuming the brain implements some kind of proxy newtonian mechanics?"
] |
[
"How serious is the proposition that life could have been brought to Earth by a meteor?"
] | [
false
] | [deleted] | [
"the idea is known as panspermia. And I think while we're learning more and more that organic compounds necessary for life exist in space (and thus are either easily synthesized, or could have been synthesized in space and landed on earth), I think the consensus is that \"life\" did not arrive from space."
] | [
"Well I personally don't think that its fully implausible. I'd give it a 10% probability and life having started in earth itself a 90% possibility.",
"The fact is that panspermia is not completely impossible or out of the blue when compared to what organisms seem to be able to do in the Earth itself, but given th... | [
"We have thirteen billion years, though life on Earth is four billion years old so we only have nine billion years to play with. Certainly there was no life in the very early universe... I'm not sure how many billion years it was before we had a significant fraction of enough heavy elements to form rocky planets, b... |
[
"Is time real?"
] | [
false
] | Physics often refers to time as a tangible thing. I've always thought it was a human created idea so I wonder, is time a real thing? If so, how do we know it it is and what is it? A dimension or a fluid field of some kind? If time is real then does that mean the past still exists in some form? | [
"In physics time is understood to be a dimension. By ",
" we mean a degree of freedom. The three (or more?) spatial dimensions tell us ",
" things are relative to each other, and time tells us ",
" things happen relative to each other. Time is as \"real\" or \"unreal\" as the spatial dimensions."
] | [
"Time is real in precisely the same way that length is real."
] | [
"Yep. Time is as real as space. In fact, they're two sides of the same coin - that coin being ",
"spacetime.",
"If so, how do we know it it is and what is it? A dimension or a fluid field of some kind?",
"As Amarkov ",
" said, it is a dimension in the same way that length, width and height are dimensions, i... |
[
"Is a mature dog more intelligent than a human baby?"
] | [
false
] | I always see these videos of babies playing with the family dog and it always seems to me in those videos that the dog is the more....grown up (?) being in that shot. Is there any merit to this kind of thinking? | [
"Yes, the intelligence of different animals is often compared to humans at some developmental age. ",
"http://www.popsci.com/blog-network/kinderlab/why-your-dog-smarter-my-baby",
"Intelligence is not a one-dimensional measure, however, so the real answer is that it depends on how you define your measure. "
] | [
"Glad you added that last sentence! I do agree with what you said but to play devils advocate I wanted to mention a scenario where I think the baby would have more measurable intelligence. If you define intelligence as the ability to learn and absorb completely foreign and new information then the baby is much smar... | [
"Maybe the baby could be said to be the best learner, but I wouldn't say smartest or most intelligent. By that reasoning humans get less intelligent as we age ...."
] |
[
"In terms of physics, how does one propel themselves on a swingset without touching the ground?"
] | [
false
] | null | [
"In the simplest terms, you contract your muscles to shift the center of mass away from being directly underneath the pivot point. This causes torque that is mediated by the tension on the rope. You can see how this happens if you find a swing that looks like a boat and place a heave ball on one end. As it rolls in... | [
"To add to this, swinging seems intuitively weird to someone thinking about the physics because it seems to break conservation of momentum: an isolated person is able to get himself moving from a stopped position. In reality, the person is not isolated. When the person contracts his muscles to change his center of ... | [
"Small motion seems kind of obvious, but I believe you're asking how does one start from a stationary swing and get their center of mass to have large swings? This requires first a small perturbation of the rope, then you need to pull up and move your body higher out of the potential during a certain part of the s... |
[
"Why do you float to the surface despite when deep in the sea there is a great pressure on you?"
] | [
false
] | null | [
"You are receiving an equal pressure from all sides, and it largely cancels out. The net force you receive is equal to the force required to hold a you-sized portion of water in equilibrium against gravity. Basically, if you replaced yourself with a you-sized portion of water, then that water should really be stati... | [
"You are receiving an equal pressure from all sides",
"You don't have equal pressure on all sides. Hydrostatic pressure is denisty * g * h. Pressure is higher the deeper you go, and this slight imbalance results in buoyancy force."
] | [
"When you dive, your equipment has extra weight which will make you want to sink overall. This is offset by having an air bladder, which is inflated during the dive at a level to cause neutral buoyancy. As you dive deeper, the bladder compresses, reducing the buoyancy force. So you have to add some of your divin... |
[
"A Quantum Physics Primer?"
] | [
false
] | null | [
"Awesome - Thank you for this. I'll ask there! "
] | [
"Awesome - Thank you for this. I'll ask there! "
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/asksciencediscussion",
"/r/physics",
"/r/suggestmeabook",
"If you disagree with this decision, please send a message to the moderators."
] |
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