title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How was the total amount of matter in the universe calculated?"
] | [
false
] | I've often heard that the matter that makes up planets, galaxies, and us, is only a small amount of the amount of true matter in the universe. And that there's also something called Dark Matter, but I've always wondered how they got the percentages that they use with regard to dark energy, dark matter, matter, etc. If ... | [
"Based on a number of different methods of indirectly observing dark matter, the most famous being differences in the ",
"rotation curves of galaxies",
" between the luminous matter we see and what you need to then account for that difference, we can then estimate how much total matter there is in galaxies and ... | [
"I see, but how precise do you think those calculations are to the actual composition of the universe? Since we don't know everything, they can't possibly be 100% or even 90% certain that their percentages are correct. As you said, they estimate the amount of total matter there is in galaxies and galaxy clusters, a... | [
"All measurements in science have errors, so I don't see a problem with this. Of course there's going to be uncertainties. We can only run through the calculations while taking into account or uncertainties and biases, and provide an estimate the total matter in the observable universe. Nobody is proclaiming this i... |
[
"Why can't we simply transplant the required healthy bacteria instead of Fecal Microbiota Transplant?"
] | [
false
] | Just figured we would have come far enough in our medical advances where we could isolate and grow whatever probiotic we so desired. Is it a matter of it just being easier to transplant the poo itself? | [
"Is it a matter of it just being easier to transplant the poo itself?",
"Yes. The gut microbiome is extremely personalized and complex.",
"We still don't know enough about how the gut microbiome effects many aspects of a person's health to assume we can recreate an ideal population or define an ideal one."
] | [
"For a long time in the future it Will probably be cheaper to just transplant fecal matter. Getting pure cultures of Every kind of gut bacteria needed may prove difficult on Its own, But mixing them in the correct ratio Will take many years to perfect."
] | [
"There is at least one proprietary mix of gut bacteria meant to be administered after a course of antibiotics in patients with recurrent C. difficile infection. It's called ",
"SER-109",
"."
] |
[
"Jewel of Quantum Field Theory"
] | [
false
] | Is this an implication of a physical simplicity previously undiscovered or a useful mathematical technique for solving equations? (Or is it a subgroup of E-8 theory) | [
"It's too early to say. So far, it's a new mathematical technique. It will need to be confirmed thoroughly before it will see widespread use in that function. If it turns out to make correct universal predictions, it might well hint at some underlying new (and more elegant) physics."
] | [
"here's a quote from the lecture, speaking about the mathematics: \"literally as you approach the boundary of the aplituhedron, on the boundary you see that it breaks up into lower amplituhedrons that are glued together in exactly the way that amplitudes are supposed to be. there's no gluons propagating in space-ti... | [
"Here's another post about the topic. Only three comments. Purpose of link is to give this very interesting and new topic some momentum.",
"http://www.reddit.com/r/askscience/comments/1nampi/what_does_it_mean_for_a_physics_property_to_be/"
] |
[
"How were the weird elements named?"
] | [
false
] | I'm talking about potassium, and lead. Why are they K, and Pb? Shouldn't it be P, and L (Le)? I was looking at the banner for this subreddit and wondered why some are named funky. My best guess is because they were discovered by scientists who speak a different language, ie. in X language, potassium starts with a K. | [
"All of these I believe are Latin.",
"The symbol for tungsten is W and comes from wolfram. I don't remember the etymology of this. Antimony (Sb), I'm not sure. Mercury (Hg) is from hydrargyrum, which I think is Greek. Might have missed some other names."
] | [
"Some of them are Latin by way of Arabic."
] | [
"Wow. First response pretty much takes the cake! Thanks man, and now that I see it, I do remember a few of those. I remember ferrum and aurum, but never made the connection between those and the rest of the ones which I now know to be latin-based. Thanks coniform!"
] |
[
"The focus seems to be on fossil fuels, but what other minerals and rare elements are in danger of depletion? What will the effects be?"
] | [
false
] | And when will it become a problem we talk about more? I imagine significantly and fiscally harvesting from landfills and space is a long ways off? | [
"Phosphorous"
] | [
"There are many numbers of economically important elements with supply problems. Among them: the rare-earth elements (REE = La through Lu), platiinum group elements (PGE = Ru, Rh, Pd, Os, Ir, Pt, Au), Ta, Hf, Ag, Cu, Zn, Sn, Ni, Co, Cr, Sb, Ge, Ga, In, and even Pb.",
"Here is an excellent ",
"summary figure",
... | [
"This is incredibly shocking and informative, thank you.",
"Too bad uranium deposits are apparently estimated to run out in about 85 years, or else nuclear transmutation and reprocessing would make me feel a little bit better about the situation.",
"I guess we have thorium and other radioactive elements but... ... |
[
"Can we understand the Planck time and Planck length as the space-time minimal \"grid\" of the universe ?"
] | [
false
] | Hello, If the universe is a simulation (i'm not saying it is) or if we want to create a simulation of the universe at the most precise level, could the Planck time and Planck length be used as a grid where every object has a quantified position ? -> Are the dimensions "analogical" or "numerical". Is there a space time ... | [
"No, that is a common misconception about what the units represent. See here for a discussion of this: ",
"https://www.physicsforums.com/insights/hand-wavy-discussion-planck-length/",
"There are also some good comments by John Baez at the bottom of that article."
] | [
"The concept of some sort of orthogonal grid doesn't really make sense for spacetime. Imagine you are looking at a photon or other massless particle. By definition it travels one Planck length per Planck time.",
"So if we map this on a grid, each tick (i.e. Planck time), it moves one pixel (i.e. Planck length).",... | [
"You can't really prove a negative."
] |
[
"Recommendations for a book on history of math and/or physics?"
] | [
false
] | I want to start out by saying that I have developed a deep love of . A fellow Redditor turned me onto this subreddit last week and I've been glued to it ever since. Thanks guys, and keep being awesome. On to the topic: I'm doing some thinking on a question and I realized I needed to understand how math and physics evol... | [
"The Discoverers by Daniel Boorstin for science. Fermat's Enigma by Simon Singh for math. If you want to read more about the history of modern physics, read the first half of The Trouble with Physics by Lee Smolin.",
"Math is just an internally consistent logic (mathematicians please don't gank me). If the univer... | [
"For a real \"history\" history, there's ",
", in several volumes. It sounds like what you're interested in is really closer to the philosophy of science. I'd look at something like Thomas Kuhn's ",
", or Godfrey-Smith's ",
". You may also be interested in Sagan's ",
" or even ",
"/r/PhilosophyofScienc... | [
"I posted a link in ",
"/r/philofsci",
", and the link was appreciated, but based on the comments there it seems a lot of them don't really know much about science."
] |
[
"How long would an Ethernet cable have to be to give perceptible amount of latency?"
] | [
false
] | null | [
"An ethernet cable would not work well over distances that large, you would most likely need to use fiber optic cables (which have roughly the same latency). To reach 80ms in a one-way trip you would have to run a cable half way across the world or to another continent. 300ms would take a cable roughly twice the ci... | [
"To further elaborate on this. Most ethernet cables are rated for around 100 meters. Ethernet cables are usually UTP (Unshielded Twisted Pair) cables, and above those lengths, the interference starts to affect the quality of the signal."
] | [
"You need to watch this.",
"Grace Hopper - Nanoseconds",
" ",
"ETA: After watching, you'll probably want to read this:\n",
"http://en.wikipedia.org/wiki/Grace_Hopper"
] |
[
"Is it possible for a planet in a binary system to have a figure 8 orbit that encircles both stars?"
] | [
false
] | null | [
"The orbit exists, but it is unstable. This means if you give the planet a small kick, it will either orbit one of the stars or be ejected from the system. More info here, ",
"http://physics.stackexchange.com/a/67260"
] | [
"It's theoretically possible but due to it being very unstable it's extremely dependent on initial conditions and lack of external influence. If the system forms with the planet being jsut slightly off the needed CoG or any passing object causes perturbations, the system will eventually break.",
"You can simulate... | [
"Also keep in mnd that \"small kick\" can be extremely small. Realistically the orbit's stability would be destroyed by one of the following sources, none of which are usually important to orbital stability:",
"All of these effects would normally be far to small to significantly affect a planet's orbit. However... |
[
"When someone receives a donated organ, do the cells of the new organ change their DNA to that of the host? What becomes of the DNA in the cells of the donated organ?"
] | [
false
] | null | [
"No, the DNA stays the same as it always was. That's why it's so important to find as close a genetic match as possible to limit the need for anti-rejection drugs. If the immune system of the new host finds the new DNA it will try to destroy the organ."
] | [
"Wow man... my knowledge of organ transplantation was never great, but this is like a harsh, harsh reality check for me. I thought once the surgery had healed up you were kind of cooking with gas. Immuno suppression drugs are basically like AIDS-lite, aren't they? So that's your option if you need an organ transpla... | [
"and even then, the organ gets worn down over the years and a transplant patient can expect to require replacement organs sooner or later."
] |
[
"Sometimes computers get stuck processing or \"hang.\" Assuming an infinite amount of time, electricity, and a stable environment, would the computer eventually finish processing?"
] | [
false
] | I work in film and animation. We use often processor intensive software like Maya, Blender and After Effects. Once in a while a machine will seem to take forever to do a task. Often the assessment is "this is taking too long, just restart and rerun the operation." Now I'm no computer scientist and I imagine there's a m... | [
"It depends.",
"If it is just taking a long time to render something, then eventually it will finish.",
"if it's hung because it's stuck in a loop, or expecting a response from something that will never respond, it will hang forever and do nothing.",
"Well written programs detect these situations and time out... | [
"Oh certainly any program of any complexity has bugs that you can't completely account for, but the point I was making was about user feedback. An hourglass tells no one anything other than some process is occuring. A progress bar can show acitivity occurring (such as a download) which if it stops moving, then yo... | [
"http://en.wikipedia.org/wiki/Halting_problem",
"Basically, there's no way to prove that any given algorithm will complete for any given input. The only way to determine it is by running it; if it finishes, it will return, if it gets stuck it will go forever, which doesn't help you know if it will ever finish.",
... |
[
"The science of distance healing & aura reading?"
] | [
false
] | null | [
"We don't allow the posting of personal theories and intuitions here. You could try ",
"/r/asksciencediscussion",
". There is no empirical evidence supporting distance healing or aura reading."
] | [
"Ok, would you or anyone know whether there is empirical evidence that dismisses it, or if there's currently no evidence linked to this subject at all?"
] | [
"Sorry, I was a little hasty in my response. I wasn't able to find any empirical studies on aura reading in reputable journals.",
"The literature on distance healing is a bit more mixed, but leaning heavily toward there being no evidence for it. ",
"Here",
" is a review of several studies that found no eviden... |
[
"How come you can literally feel a \"heart break\" in your chest?"
] | [
false
] | [deleted] | [
"I think he's referring to adrenaline release from stress. I know that I've had that same feeling during a break-up, or when something triggers jealousy, there is a burning feeling in my chest. I don't know why it is felt in the chest area, and Google doesn't seem to know either. But, my guess would be something re... | [
"I think he's referring to adrenaline release from stress. I know that I've had that same feeling during a break-up, or when something triggers jealousy, there is a burning feeling in my chest. I don't know why it is felt in the chest area, and Google doesn't seem to know either. But, my guess would be something re... | [
"Angina can be precipitated by emotional duress or anxiety as it is a typical response to stress",
".",
"Stress is the key factor in the situation of the ending of a relationship or other similar hardship; ",
"stress causes a host of problems",
", and may induce an endlessly vicious cycle of painful side ef... |
[
"Why do meteorites have a crystalline looking structure?"
] | [
false
] | I've been looking at meteorite rings lately, and I've noticed they all seem to have a lined, sort of crystalline structure, such as . I began wondering if that was just the finish of the ring, or if the metal actually looked that way. I did some googling, and found picture, and thought maybe it was just the way they cu... | [
"Not all meteorites have those crystalline structures. The pictures you linked are all Octahedrites, and when cut they exhibit ",
"Widmanstätten patterns",
". I believe the second picture is of a fragment of Muonionalusta, recovered from northern Scandinavia, and the third, the sphere, is of Gibeon, recovered f... | [
"So the rings I'm looking at, are they legitimately meteorite rings? Seems like a bit of a rare substance to get your hands on and make a ring out of, so are they actually real meteorite? Thanks for the information on the nickel iron crystals, that's very interesting."
] | [
"I don't know much about jewelry, but they certainly look like real meteorites."
] |
[
"What would we hear if we played a sound with a frequency of 10000 Hz 200 times a second?"
] | [
false
] | By 200 times a second I mean a situation when the sound would be played for 2,5 ms, followed by 2,5 ms of silence. Would we hear a sound with a frequency of 10000 Hz, 200 Hz, or something entirely different? | [
"This"
] | [
"https://soundcloud.com/librans/10khz",
"I made this using a frequency modulation synth. the last tone is a 200hz square wave being modulated by a 10khz sine wave."
] | [
"It would sound a lot like 200hz. Any type of sound repeated evenly 200 times a second would sound like 200hz - the shape of the sample affects different aspects of the sound, but not the pitch. ",
"The brain's capability of interpreting soundwaves as a pitch, depending on the shape of the wave, starts at 10-20Hz... |
[
"What are some ways to block pain transmission in nerves? What physiology background should I know first?"
] | [
false
] | null | [
"You'd need to have a good understanding of how sensory nerves transmit impulses. Basically, once a nerve is activated, it sends an electrical signal along the length of its long body (the 'axon') to the brain. Often, but not always, many nerves are involved in a chain to transmit the signal. ",
"To understand ho... | [
"Thanks a lot for your information.",
"I was just thinking if I wanted to localize targeting to remove joint pain in the knees or armwrist for instance and I wanted to create an external device to stimulate the nerves.... Does it have to be attached to the spinal cord or the brain region? Or can I just hook a dev... | [
"If you want to stop pain being perceived you could either interfere with the transmission of the signal, or change how the brain perceives it. To be honest, I'm not sure how the brain processes sensory/pain signals so my instinct would be to avoid the brain (though hopefully someone with better neuroscience than m... |
[
"Is the wave function of a particle only a mathematical description or is it actually some sort of wave. Is there any difference between something being a wave function and being a wave?"
] | [
false
] | In particle physics, particles are said to behave like a wave when they are not observed. Does this mean it's actually some sort of wave or is it just best described by a wave function? Or does a wave function only describe a wave? | [
"There will be some people with strong opinions replying to you, but the truth is that we cannot answer this from our current state of knowledge.",
"Interpretations that think the wave-function is a real physical object are called ",
", while interpretations that think the wavefunction only describes our knowle... | [
"The wavefunction is the true nature of matter, and phenomena such as waves and particles are just emergent phenomena we see on a larger scale, not the other way around. Simple wawefunctions are just mathematically similar to classical wave equations you'd use to describe waves in a medium such as in water or air, ... | [
"It's a \"wave\" (I explain the quotes below). Far too much emphasis is placed on thought experiments of measurements of a single particle. If one simply switches focus to the behavior of many many particles then the question is pretty clear. From that perspective, the (square of the) wave function is just the c... |
[
"If you were born and raised in space, would you have a greater resistance and management of UV/IR radiation?"
] | [
false
] | null | [
"Like others have said, probably not. From what we know of human development going from Africa to Europe skin changes did occur but the time estimates between small landmark changes are spaced by several thousand years, and that wasn't entirely due to changes in UV exposure but also dietary deficiencies. To have a ... | [
"The ethics of performing those kinds of experiments are difficult, to say the least."
] | [
"No, for a couple of reasons.",
"1) Lamarck got it wrong and Darwin got it right. Being born in X doesn't make you better at X. However, if 1M people are born in X then most will die, but after generations the survivors will be better at X. So it's no benefit to you directly.",
"2) Physicists have a joke that a... |
[
"Why does a ceiling fan seem to rotate slower when viewed in a mirror?"
] | [
false
] | Perhaps slower isn't quite the correct term. I've noticed that when one looks at a ceiling fan, moving at a high rate of rpm, it's impossible to distinguish the individual blades, but if one looks at a reflection of the same fan in a mirror, the blades become somewhat visible, and the rotation itself seems to break up ... | [
"It's going to be hard for anyone to answer your question, and all answers are going to be plausible guesses that may or may not be correct.",
"That said, I do know a bit about the human vision system, and it maybe due to the fact that the fan appears further away in the mirror. So it looks smaller, and you can f... | [
"So I just did a bit of observation, and it supports what you say.",
"It is, indeed, easier to distinguish individual blades when I am further away from the fan (however, I am near-sighted, and have no corrective lenses to test with, so this may bear some weight on my observations), and they seem to be easiest to... | [
"I'm not sure if this is the cause, but perceived speed is dependent on contrast. If the mirror were reducing the contrast (compressing the brightness level) it could reduce perceived speed of the fan.",
"I'm not sure about DoorsofPerceptron's answer. I would say the foveal eccentricity (distance to the center of... |
[
"Is there a noticeable difference in the eye muscles between cultures that read left to right and cultures that read right to left?"
] | [
false
] | null | [
"I work with computer vision researchers who have explained this to me a few times, so secondhand citation syndrome in effect.",
"Your eye movement patterns are vastly predominated not by conscious, voluntary things like reading, but involuntary ones—so-called ",
"saccadic eye movements",
" are happening all ... | [
"Muscles, no.",
"But there may be some interaction..",
"We don't have \"eye dominance\" the same as handedness. Instead, the entire right field from both eyes may be \"dominant\" (like handedness) and \"dominant eye\" is a different process than dominant hand.",
"Half the visual field always crosses over at t... | [
"Thanks kind stranger"
] |
[
"Geologists of reddit, how is a mesa formed?"
] | [
false
] | A friend and I were have a bit of a question about how the Utah Mesas are formed as opposed to the steeply peaked hills in China ( ) as far as how much hydrological and pneumatic activity vs glaciation played into their formation. If some one could explain it like we were five, we'd really appreciate it, thanks! | [
"The difference between the Utah Mesas and the steeply peaked hills in China that you have provided a picture of is related to both the geological composition of the formations and the weathering environment of both locations. ",
"Mesas are formed by a process called differential erosion, where two rocks of diffe... | [
"Thank you. That was very informative."
] | [
"Those are called ",
" and you are correct. They are formed in a similar fashion to mesas, buttes, pinnacles and plateaus."
] |
[
"Is there a maximum possible acceleration?"
] | [
false
] | null | [
"Not by any physical law. There are practical limits, such as what a human could survive if you are talking about rockets. There are also practical limits in terms of “it would take more energy than exists in the universe”. But you could accelerate at any rate, as long as velocity stays below c. "
] | [
"Our current laws of physics don't work for accelerations larger than the Planck acceleration, defined as the speed of light divided by the Planck time. We simply can't meaningfully describe processes faster than a Planck time.",
"10",
" m/s",
" is far beyond any acceleration we can reach in experiments (or i... | [
"You can have an acceleration of C/s for any duration you like, in your frame."
] |
[
"Did we know the temperature of space before we went there? How?"
] | [
false
] | I just learned that space is 2.7 Kelvin (-255 degrees Fahrenheit). If this is true, did we know this before we visited it? How? If we didn’t know, how did we survive that temperature? | [
"2.7 Kelvin is the temperature of the cosmic microwave background (CMB). If you are far away from any galaxies or other stuff then that's the temperature of the radiation around you. The temperature of gas or other stuff in galaxies or elsewhere can be very different from that. For the temperature of objects in the... | [
"Short-term: Not a strong feeling in either direction. You only have radiation as mechanism, that's relatively slow compared to heat transfer with the atmosphere. Long-term you freeze to death or overheat depending on the amount of sunlight, infrared radiation from Earth or other objects (if nearby), and the surfac... | [
"What does temperature mean? This question isn't as easy and obvious as it might seem. ",
"The deepest answer in physics would most likely be, that temperature is the inverse of the derivative of entropy with respect to energy. ",
"This is called thermodynamic beta.",
"But this answer isn't very useful for ev... |
[
"Does the placebo effect still occur if you understand it?"
] | [
false
] | null | [
"\"Maybe it's not a placebo and they're telling me this to compare against placebo\"."
] | [
"According to an IBS medical trial recently, the placebo effect does work, even when patients are told they are on placebos.",
"Link to article",
"Link to the study"
] | [
"The old double-placebo. It's like reverse-reverse psychology."
] |
[
"What is humanity's best chance to get to another solar system, aka travel space/time"
] | [
false
] | Is there any hope the we will be able travel faster than light and thus get to another solar system within our lifetimes? | [
"Is there any hope the we will be able travel faster than light and thus get to another solar system within our lifetimes?",
"The answer to your question is a simple ",
". According to modern physics, faster-than-light is absolutely impossible. But that won't stop a horde of starry-eyed scifi fans from raving a... | [
"No, we cannot travel faster than ",
" - we will probably never be able to travel near ",
" either, as they energy required becomes exponential. ",
"As BubbleBobble-007 alluded to, the shortest way to get from A to B is always a straight line, but if we can curve spacetime, and make a bridge, then this can ... | [
"There are other theoretical ideas of getting a spacecraft up close to c such as inducing a gravitational field, and riding a gravitational wave if you will, called the Alcubierre drive",
"The Alcubierre metric isn't a theoretical idea. The author never ever proposed this was possible. It is positively ",
". It... |
[
"In a tilt gear wand, specifically the ones used to open and close blinds by turning, is there more leverage or torque grabbing and twisting near the top or near the bottom of the stick?"
] | [
false
] | I have really big heavy blinds and my wife has trouble turning them. Would there be any difference in her turning them by grabbing the top middle or bottom of the stick? If there is why is that? | [
"She would get more from twisting it near the top.",
"The rod has a certain amount lf elasticity, and that is going to absorb some of the \"twist\" before transfering it to the mechanism.",
"This could be a realy tiny effect, or a decently sized one mostly dependant on the rod. ",
"But either way she will get... | [
"In torsion, angle twisted of ROD is a function of both torque and length so you are absolutely right. ",
"Tl/JG = angle of Twist \nT - torque \nl - length over which moment applied and resisted \nJ - polar moment of inertia \nG - shear stress modulus",
"We want angle of twist to be minimum and angular displace... | [
"Since the diameter of the rod is constant there is no mechanical advantage for turning the rod at the top or bottom, the only advantage is ergonomic. For me it's much easier to to turn the rod with my arm bent 90° at the elbow to adjust the slats, and to grab the rod at the highest point comfortable to slide the m... |
[
"Why is the pericardium shiny and slippery?"
] | [
false
] | Pericardium being the membrane that surrounds the heart. | [
"The short answer is that the smooth surface of the pericardium and the serous fluid it secretes allows for a low friction cushion that surrounds the heart. "
] | [
"To reduce friction wear and irritation on the heart as well as act a shock absorber for impact. "
] | [
"It is shiny and slippery because it's thin, \"The parietal pericardium is a fibrous structure that is <2 mm thick and is composed primarily of collagen and a lesser amount of elastin.\"1 In terms of function, one of the things the pericardium does is prevent the heart from over-expanding and provides an extra leve... |
[
"Analytical chem question: how to interpret mass spectra for an unknown compound?"
] | [
false
] | I'm currently trying to get some preliminary IDs on a number of hydrocarbons; mainly just trying to get an idea of if they're double-bonded, if they have functional groups like aldehydes, carboxylic acids, etc. I realize determining exact structure is not possible. I've attempted calculating retention indices (with an ... | [
"Let's start with that. "
] | [
"Yeah, GC-MSD, using a DB-1, that helps me understand what type of artifacts that can come in with it.",
"What software are you using to control the GC-MSD and do integration/quantitation?",
"And your matrix is essentially whatever your analytes in question are mixed in. Are they soil samples in your dichlorom... | [
"Insect cuticle? That seems very small. Are you saying nanograms total or nanograms per milliliter (ppb range?)",
"If it's nanograms total, how much solvent did you use to prepare your sample?"
] |
[
"Why aren't computer motherboards componentized?"
] | [
false
] | Recently, I've been out shopping for a new mobo since my old one was on the fritz. After comparing specs of different motherboards, I got to wondering why the different parts of the board aren't separate components that you can just plug together. So for example, you'd have your base CPU component that accepts a compon... | [
"To some extent it is. Remember that a DIMM goes into a slot that can accept various sizes of memory. Most motherboards have more than one port of various types (PCIe, PCI, SATA, etc.). ",
"But it sounds like what you are saying is allowing for an ",
" number of, say, DIMM sockets. Those sockets need to be s... | [
"To add to what ",
"/u/afcagroo",
" stated, keep in mind the level of reliability that computers are held to. In enterprise class machines you can see computers running with 99% uptime and substantial loads for months or years, performing quadrillions of operations and pretty much never making a mistake. That... | [
"The biggest lie about your computer is that it's just one computer; it's really dozens of independent processors and environments lashed together. Often these parts are pretty cheap and are unlikely to be swapped out. These parts stay on the motherboard. A few parts, like hard drives and video cards, are indeed... |
[
"Help in Identifying a little bug"
] | [
false
] | As I was taking out something of my mother's car, I've found a strange bug on one of its doors. I immediately took some pictures and thought of asking here if someone knows what bug this is. Here's a link to the album with some photos: I've included a picture of my finger beside the bug to help have a reference to its ... | [
"/r/whatsthisbug",
" is that way <<"
] | [
"Btw it's a Plume Moth."
] | [
"Ha! I didn't even know there was such a subreddit. I'll post it there. Thanks."
] |
[
"How is the anatomy or structure of an organism encoded in its genes?"
] | [
false
] | [deleted] | [
"Life begins with a small blob of cells. Cells comunicate with one another by direct contact and by emitting transmitters. When this blow reaches a certain size, based on the orientation of the blob towards the future placenta (or alternative), different regions on the blob determine the orientation of the whole ne... | [
"just a small correction: The one gene one protein hypothesis was shown to be wrong for eukaryotes. Because of mechanisms like splicing, one single gene can result in different functional proteins and RNA."
] | [
"just a small correction: The one gene one protein hypothesis was shown to be wrong for eukaryotes. Because of mechanisms like splicing, one single gene can result in different functional proteins and RNA."
] |
[
"There are people in prison who are later exonerated. Have there been any scientific studies comparing how these people behave in prison compared to the rest of the people in prison?"
] | [
false
] | null | [
"Well, it is difficult to identify those inmates who are wrongfully convicted while they are incarcerated. Many of the people in prison claim that they did not do the crime for which they are imprisoned. However, most accounts relate that those inmates who are wrongfully convicted are treated differently than othe... | [
"[Masters in Clinical Psychology (Forensics Emphasis), working towards Doctorate]",
"Prison culture is pretty uniform. There are flavors and variations depending on the correctional philosophy of the administrators, geographic location, racial makeup, security level, and offense type, but they all tend to overlap... | [
"I think it would be very interesting to see if any studies had been done comparing their behavior after getting out too."
] |
[
"Where are fruit flies hanging out when there is no fruit? The minute you have day old fruit they seem to come out of nowhere from some dormant sleep."
] | [
false
] | null | [
"Actually, as a yeast geneticist, I wanted to clear up a common misconception about fruit flies. While they may eat some of the rotting fruit, their real target is the ",
"naturally-occurring yeast",
" that grows on the outside of fruit and causes the fermentation/rotting to occur.",
"I can't begin to tell y... | [
"you are right, found this: (I had no freakin clue they layed their eggs directly in the fruit)",
"\"The fruit fly life cycle begins when a fertilized female locates a piece of fermenting fruit or other source of fermenting sugar in which to lay her eggs. She can lie up to 400 eggs at a time and male and female f... | [
"If for some reason you do not have plastic to cut up, any vessel containing vinegar and dish soap will attract the buggers and drown them."
] |
[
"From a quantum physics standpoint, how exactly do LEDs produce photons, and how efficient are they?"
] | [
false
] | null | [
"WARNING: Long post ahead",
"Alright, the key thing you have to understand is how electron behave in a solid.",
"Electrons in a solid can only have certain discrete states and, as is the nature of all fermions due to the Pauli exclusion principle, there can only be one electron in each state. So if we imagine ... | [
"What happens if an electron absorbs a photon with an energy ",
" than that of the band gap, as opposed to the exact amount?"
] | [
"An \"excited\" electron with energy more than thermal equilibrium will shed this excess energy by scattering off other degrees of freedom. Usually the most important is phonons (i.e. atomic nuclei). On average such an electron will travel/\"make it\" a distance called the \"thermalization length\" before it's ba... |
[
"Can there be a planet with hot poles and cold equator?"
] | [
false
] | If yes, what condition have to occur to make it possible? I know that axial tilt equal ~90 won't do it, because it makes both poles and equator the hottest places. | [
"Yes, there definitely should be.",
"I know that axial tilt equal ~90 won't do it, because it makes both poles and equator the hottest places.",
"That's actually not true. If a planet's axial tilt is greater than ~54 degrees then, ",
", it will receive more sunlight at the poles than the equator. So, if you g... | [
"Well, it's exactly what I laid out above, namely:",
"Have a planet with an axial tilt greater than 54 degrees",
"Be at a depth in the atmosphere or surface where the thermal inertia is large enough that you're not affected by daily or seasonal variations."
] | [
"Right, for even larger axial tilts, the equator would be the coldest place on the planet. I made ",
"this diagram",
" that shows the insolation (incoming solar radiation) averaged over the year vs. latitude for a variety of different obliquities (axial tilts). ",
"You can see the transition from poles-colder... |
[
"Guy takes a picture of a completely dark room - What is showing up in the picture?"
] | [
false
] | It isn't completely black, so what's the picture showing? | [
"Depends on what medium he used. ",
"If it's a digital camera, as others here have already noted this will be thermal noise from the CCD or CMOS chip, and from the amplifier and the analog-digital-converter units after it.",
"If he used chemical photographic film, it's either a slight accidental pre- or postexp... | [
"If he used chemical photographic film, then he also scanned it. A lot of the noise could be thermal noise from the scanner.",
"But it's most likely shot with a digital camera. "
] | [
"This is indeed thermal noise from a digital camera. When doing astronomy photography, I take a picture of the inside of a lens cover to get an image of JUST the thermal noise, and use that template to subtract the noise out of my actual pictures. My black pictures look exactly like the post."
] |
[
"Why did the radiation from Hiroshima not last as long as the chernobyl disaster?"
] | [
false
] | Was it the power of the explosion blowing the radiation away or was the bomb designed in such a way as to avoid long lasting fallout? | [
"in chernobyl you have 180 tons of radioactive material in the core. A nuke contains 0.05 tons of radioactive material.",
"There are of course differences: a very violent explosion that absolutely vaporized the bomb and a violent explosion that desintegrated the core and vaporized some. One burst in the air, the ... | [
"The Chernobyl disaster happened on the ground while the bombing of Hiroshima was up in the air. The radiation levels of Hiroshima are identical to any other place on Earth; this is because the explosion was in the air and all radioactive material was blown away by wind elsewhere.",
"The Chernobyl disaster spread... | [
"Another thing to consider is that nuclear power plants and nuclear bombs don't produce exactly the same type of radioactive materials, and the radioactive material released in either case is a heterogeneous mixture of many different radioisotopes; this is important in assessing long term behavior. ",
"As delete_... |
[
"Can angle of window blinds affect room temperature?"
] | [
false
] | Given the recent heat wave, I was wondering if there is an optimal blind angle to reduce heat. Since heat rises, would angling the blinds downwards force the rising hot air to exit your room? (crappy drawing: ). And vice versa, if I pointed them up would it catch rising hot air from outside and bring it inside? | [
"Are the blinds leading to outside? Or to a window?"
] | [
"Mesh window"
] | [
"Yeah I would imagine during the day sunlight would have a larger effect. What about at night when it is still hot in you room?"
] |
[
"AskScience AMA Series: We're from the Pacific Northwest National Laboratory and we research pumped-storage hydropower: an energy storage technology that moves water to and from an elevated reservoir to store and generate electricity. Ask Us Anything!"
] | [
false
] | We are Dhruv Bhatnagar, Research Engineer, Patrick Balducci, Economist, and Bo Saulsbury, Project Manager for Environmental Assessment and Engineering, and we're here to talk about pumped-storage hydropower. "Just-in-time" electricity service defines the U.S. power grid. That's thanks to energy storage which provides a... | [
"Let's say you get 1 GWHr from the grid to pump water uphill. How much energy would you be able to return to the grid when the same volume you pumped uphill comes through the turbines? What's the round trip efficiency?"
] | [
"Great question. Round-trip efficiency (RTE) is an important part of the overall value equation. If, for example, you charge the PSH system during low-price hours, store the energy for several hours, and then discharge onto the grid, higher RTE losses means the price differentials must be greater to make up for the... | [
"Thanks for doing this! I just watched ",
"this excellent talk",
" by Jesse Jenkins at the University of Pennsylvania which talked about how \"flexible base load\" is the missing piece of our future energy grid and how pumped hydro is one of the few technically feasible options we have. "
] |
[
"Why are airplane seatbelt buckles different from the ones in cars?"
] | [
false
] | Do the different designs make one better for a certain application than the other? Is it different safety standards? | [
"The 3-point belt you where in a car is meant to keep you from shooting out forward when you come to a sudden stop. The belt on an airplane is meant to strap you down to the plane so that if it suddenly drops in turbulence, you don't hit your head on the ceiling.",
"A sudden stop on an airplane would kill everyon... | [
"What about the latching mechanism? Why is that different?"
] | [
"I have a vague recollection that the first \"safety belts\" installed in cars back in the late '50s/early '60s used the same kind of latching mechanism as in aircraft. Why the design changed, I have no idea."
] |
[
"Could we feasibly build a particle accelerator to probe physics at the GUT scale?"
] | [
false
] | [deleted] | [
"The GUT is scale is ~ 10",
" GeV. The current collision energy of protons at LHC is 1.3 x 10",
" GeV. It'd be quite some time before we can overcome the energy barrier of 12 orders of magnitude."
] | [
"More like \"given that we can make a ship that is 500 meters long, can we also make a ship that is 500,000,000,000 km long?\""
] | [
"The question makes sense but the scale required is just so flantzabishly larger than what current exists that it's sort of like saying \"given that we can make a ship that is 500 meters long, can we also make a ship that is 5000 miles long?\""
] |
[
"Why do poured liquids look like braids?"
] | [
false
] | null | [
"Heckuva loaded question, because there are a whole lot of factors as to why this happens, spout geometry, surface energy, viscosity, and density.",
"However, the main reason is because of the surface tension on the liquid. If water is coming out of a nominally flat spout similar to that coffee pot, the surface t... | [
"The liquid starts out in a flat shape. Surface tension tends to pull it together (circles have the lowest surface to volume ratio)",
"Surface tension pulls the sides inward, where they crash into eachother and widen out perpendicularly. (The cross section doesn't stay circular because the liquid still has some k... | [
"Conservation of momentum and energy both apply here (obviously, laws of physics here). But yes, it is basically a harmonic oscillation, and the latter is probably the more apt choice for getting the point across. As the stream geometry goes from circular to ovular again, the water once again has increasingly large... |
[
"What does black body radiation emission have to do with quantum theory?"
] | [
false
] | I am a mathematician and I am familiar with the formalism of quantum mechanics. In virtually any quantum mechanics course I would run into this remark that the idea that electromagnetic energy is emitted in portions --- quanta --- was introduced by Max Planck in connection with the problem of black body radiation. With... | [
"It's called the \"ultraviolet catastrophe\".",
"The Rayleigh-Jeans law, ",
"which explains spectral radiance classically",
", only agrees with experimental results at high wavelengths. Because it contains a (wavelength)",
" term in the denominator, it blows up at even moderate wavelength and diverges to i... | [
"In classical electromagnetism, we can calculate what equilibrium at a temperature looks like based on standing waves in a cavity. This yields the Rayleigh–Jeans law,",
"\n",
"http://hyperphysics.phy-astr.gsu.edu/hbase/mod6.html#c6",
" ",
"The issue is that if you poke a hole in this cavity, at equilibrium... | [
"In the classical setting there is a theorem called the equipartition theorem that says each harmonic oscillator (wave) mode will have the same average energy (of kT/2). If you treat light as a wave inside a resonating cavity, then the number of allowed wave modes approaches infinity as the frequency goes to infin... |
[
"Can humans see an atom through a microscope? Is it visible? How does it look like?"
] | [
false
] | I do believe I've read somewhere that the technology have yet to find away to see an atom, or something that is really small, an electron maybe. But I'm pretty sure there was something that was not visible, and were being taught to us in the most convenient shape scientists think it looks like. Sorry for being vague. | [
"sorta...",
"electron microscopes and other processes make it possible",
"heres a picture of \"atoms\"\n",
"https://qph.is.quoracdn.net/main-qimg-b1c72b2f8dbbdf0da3be7961662edf50?convert_to_webp=true",
"heres a picture of \"an atom\"\n",
"https://qph.is.quoracdn.net/main-qimg-9ef061f0d7878bff548edf095103d... | [
"In second picture what are the colours signify? mass? temperature? charge?"
] | [
"We have \"microscopes\" that can make out individual atoms, but they don't use light. Visible light has a wavelength orders of magnitude higher than the size of an atom, so it won't be noticeably disrupted by a single atom."
] |
[
"Are we just lucky that covid does not have a higher mortality rate or is this because more deadly infectious diseases are less common?"
] | [
false
] | [deleted] | [
"Higher mortality diseases get quarantined more aggressively.",
"If COVID had a 15% case fatality rate and most survivors were left permanently disabled, Wuhan would have been in hard lockdown four weeks earlier. Similar actions were taken when Africa had an ebola outbreak.",
"Because the disease is 80% 'less d... | [
"What if it’s 100% deadly and has very long incubation period around 3 months or longer like rabies\nbut airborne and very infectious while asymptomatic?",
"If this virus were to exists, it would be the end of humanity, no?"
] | [
"While a super high lethality rate would have caused the virus to quickly burn out, something in the 10-20% range easily could have spread out of control. What every commenter I have seen here is forgetting is that COVID-19 can be transmitted asymptomatically for up to 12 days. SARS, which had a lethality rate of a... |
[
"Where does the explosive energy of an airbust meteor come from?"
] | [
false
] | So I've been reading a little bit about the and the , both of which have been attributed to a meteoroid exploding in "airburst" event, with the object blowing up in midair after entering the atmosphere. I am wondering where the explosive energy (enough to generate a powerful shockwave) comes from in this sort of phenom... | [
"The explosive energy comes mainly from the meteor's kinetic energy. Specifically, the meteor compresses the atmosphere in front of it. When the high-pressure air in front of the meteor seeps in to the cracks and pores of the meteor's surface, eventually the pressure inside the meteor will be enough to overcome it'... | [
"Think about it this way: a meteor has a certain amount of kinetic energy (generally a LOT because kinetic energy is mv^2 and typical speed is like 20 km/sec), but is relatively aerodynamic.",
"When the meteor suddenly disintegrates, its mass doesn't change, but it suddenly slows down due to air resistance. OP'... | [
"I think \"pressure inside the meteor\" in this case means the kind of pressure that's inside a marble as you're squeezing it with a hydraulic press, or, less destructively the kind of pressure that's inside a compressed spring and not the kind of pressure that's inside a balloon that's about to pop. I'm not sure a... |
[
"The mitochondria and chloroplast are examples of endosymbiotic relationships, but are there any other examples of eukaryotic cells forming an endosymbiotic relationship with another organism?"
] | [
false
] | If there aren't, then what stops cells from forming such relationships? If there are, what is the nature of the symbiotic relationship, and are they able to pass on these endosymbionts to subsequent generations? | [
"Corals have a symbiotic relationship with Zooxanthellae. The symbiont performs photosynthesis and helps feed the coral. The coral aids the symbiont with waste removal, safety, and a supply of carbon dioxide. Corals are not born with symbionts, they acquire them from the environment. In times of stress, the coral m... | [
"There is still research and debates being conducted on this topic, but there is some evidence to suggest flagella, cilia, and/or the nucleus were once prokaryotic cells which were engulfed. The issue with tracing back the origins of these organelles (those that are not mitochondria or chlorplasts) is that they do ... | [
"Interesting. I hadn't considered that this relationship was the result of endosymbiosis."
] |
[
"Theoretical Fiction with Anti-Gravity materials"
] | [
false
] | null | [
"Wait, so that means if you hold Anti-matter in your hand, your hand will blow up?"
] | [
"Wait, so that means if you hold Anti-matter in your hand, your hand will blow up?"
] | [
"Not only electrical charge. Lepton and baryon numbers are also reversed, and in the case of quarks and gluons antiparticles have opposite color charge as well. If you want to turn a particle into an antiparticle (on paper, obviously) you have to hit it with the charge conjugation, parity refection ",
" time reve... |
[
"Why do we feel emotion from music?"
] | [
false
] | Apart from the lyrics, what makes music so expressive if it's just a bunch of soundwaves? Why do we associate emotions with certain pieces of music? | [
"Neuroscientist here. ",
"\nA combination of cultural (learned) experience and resulting anticipation. When our brains recognize a musical pattern, our experiences provide us with expectations for what happens next. For instance, horror movies tend to take advantage of our past (cultural) experiences of ... | [
"Imagine music to be a stimulus for the brain - similar to other physical stimuli such as images (in the form of cinema, perhaps), food, and drugs. Music just chooses our sense of hearing to be its medium. These sound waves that we perceive can be imagined if we see the analogy of a cinema - perhaps each frame of t... | [
"Excellent question! Science doesn't yet have a perfect answer that is completely guaranteed to eliminate unwanted associations, but perhaps the following will help:",
"Don't try to forcefully block out the person from your mind. Attempting to cover up an association may make it even stronger. Instead, accept ... |
[
"What is the ratio of food that you eat to what comes out? If you eat a one pound sandwich, what percentage is eliminated?"
] | [
false
] | null | [
"Also, how fast is poop made. If I ate a meal, when will it come out?"
] | [
"Depends on your body. Quickest way to find out: EAT A LOT OF CORN in one meal.",
"The husks of corn does not digest well in our bodies. You can pretty much time it by eating it and seeing when it will appear in your fecal matter.",
"But! Stuff like chewing can get your intestines moving the fecal matter along ... | [
"You absorb ~90%+ of the carbohydrates and fat, and ~70-80% of the protein (depends on the source). Water is absorbed based on the level of your hydration. More fibres means less absrobed (most are insoluble). Your sandwitch is mostly carbohydrates (and water) so you'd absorb most of it. And while on the subject of... |
[
"Is there any truth to this tale about Andre the Giant helping provide a \"medical breakthrough\" in the field of anesthesiology?"
] | [
false
] | I came across about wrestler Andre the Giant's legendary drinking abilities and found one part in particular quite interesting: (For context, this incident probably would've taken place between 1986 and 1987.) Andre was in France visiting his ailing father when the call came. He thanked Vince Jr. but said there was no ... | [
"Sorry, I have been in the practice of anesthesia for 20+ years and this is a new one on me. Use of ethanol does affect and/ or correlate with anesthesia action to some extent, but only very roughly. Induction doses are based mostly on ideal body weight; inhaled doses are based on partial pressure and are (largely)... | [
"So out of curiosity, how would you go about determining the dosage for an Andre-sized patient?"
] | [
"According to Wikipedia, he was 2.24 m tall (7 feet 4 inches) and weighed 240 kg (at his heaviest) when he was wrestling. That puts his body mass index at 47.8, which is in the \"morbidly obese\" category. BMI is weight in kg divided by the square of the height (in meters). Less than 18 is underweight, 25 is \"i... |
[
"If I have two round magnets stuck to eachother, with a surface between them (like a pane of glass), and I rotate one of them, will the other one rotate with it?"
] | [
false
] | Thank you very much for all the responses, everyone! This have me exactly the information I was looking for. | [
"Can confirm: it works. I've been doing this since I was a kid. More below as to ",
" and ",
" this works.",
"The question should be, more appropriately: would two perfectly crystalline, perfectly round ",
"ferromagnets",
" rotate with respect to each other (",
" magnetism) through a surface? And the sh... | [
"I'd say yes. Get two magnets and try. I think a cheap disk magnet has to be at least a bit off-axis."
] | [
"I just tried it with 2 small, neodymium disc magnets (this one), and the second magnet did NOT rotate. I tried it once with a file folder and once with an 1/8\" thick piece of polycarbonate. Nothing.",
"Neodymium magnets are far too powerful for that length scale. The friction force is directly proportional to t... |
[
"Just bought a USB rapid charger. How does a rapid charger work? And why aren't all chargers rapid chargers?"
] | [
false
] | null | [
"So, how quickly your phone is charged is essentially based on the amount of power that it receives from the charger. The current standard is roughly 5V, 2.1A (at least in America, I don't know if it's different in Europe). Most devices have regulators that prevent any more power from getting to the battery for saf... | [
"Not exactly right. The usb 2.0 standard is 0.5A, which computers usually limit to. The charger sets a voltage (like 5v) and de phone decides how much current it takes. Cell phone chargers have a resistor that tells the phone it can deliver more current, some phones use 1A, and some 2A.\nTo deliver more power means... | [
"It is the same everywhere, at least for USB chargers, but USB specifies 5V 0.5A . with more power hungry devices more current has become common though"
] |
[
"Would you be able to measure your speed relative to the rest of the universe with the speed of light?"
] | [
false
] | What I am saying is, would you be able to measure your speed and the direction you are travelling in relative to the while universe? E.g. If you had a laser and flashed it at a detecter and calculated the speed to be the speed of light plus 100km/h, would that mean relative to the rest of the universe, the set-up is tr... | [
"The speed of light is constant in every reference frame. So no matter what you're doing, you'll always measure the speed of light at 299,792,458 m/s.",
"Related to that is the fact that there is no universal rest frame. That means, there's no \"relative to the universe\" when it comes to motion. Motion is always... | [
"To further illustrate this:",
"The universe has no \"center\" - there ",
" no fixed point - or even \"average point\" to call the \"base\" for the whole universe.",
"You can see this within our own solar system. We say that the Voyager and Pioneer probes are \"leaving the solar system\" and mention a specif... | [
"One thing that helped me understand it was that 'speed of light' is a bit of a misnomer. Yes, it is the speed that light travels at, but that is not a property only of light.",
"c is the definite speed limit in the universe, and nothing with mass can ever reach it -- conversely, things without mass must always t... |
[
"Energy generation: is our sun the ultimate source? If not, when and why would another source be preferred?"
] | [
false
] | As a layman, it seems that despite current technological limitations, solar energy would be the most fruitful to develop. Is that true? What barriers are present for this technology? What do you see for the future of solar? | [
"A lot of things are meant by solar. But I'll just say that the sun is the only energy ",
" to our planet. Fossil fuels are stored solar energy. Fission and fusion is technically a limited source of energy, even if not in practice. "
] | [
"Ah hah! What about ",
"tidal power?"
] | [
"Stolen from the rotational kinetic energy of the earth?"
] |
[
"Why are always purines being used for energy delivery?"
] | [
false
] | I always see cascades where there are G-proteins involved which obviously interferes with GTP and ATP is involved in so many reactions for instance muscle movement and what not. But why is it always the purines and never the pyrimidines? Might it be because of the little extension of the aromatic ring of the purines? | [
"This is a question I wrestle with a bit, I work on a protein that binds GTP, while its closest relatives use ATP.",
"I'm not certain this is known why certain purines have specific roles. It's possible we might run evolution again and find out that CTP was the central energy carrier while UTP was used for regula... | [
"Almost certainly yes. ",
"/u/superhelical",
" was hinting at this when they pointed out that if we ran evolution again we might end up with a CTP/UTP system instead. That is once one energy carrier (ATP) was fixed on early in evolution it has indeed been kept ever since by everything else. You see these kind o... | [
"This might end up being a silly question but... could this not also be a case of a somewhat primitive system being vital enough to be conserved without much deviation?"
] |
[
"How much does it really help wearing white clothes versus black clothes in the sun?"
] | [
false
] | null | [
"Which color keeps you cooler depends a lot on whether the clothing is tight or loose. If you're wearing, say, white spandex, then the light from the sun will be reflected most efficiently, and you will stay cooler than if you were wearing black spandex.",
"On the other hand, what you see people wearing in hot, ... | [
"This, plus darker clothing has a slightly higher spf than lighter clothing. That can make a big difference when you're outside all day. ",
"I grew up in a desert and in the summer, I would wear a loose tank top with a loose t-shirt over that. Jeans are alright, but the denim can get damp when it gets too hot, le... | [
"As someone who knows nothing about this subject, I don't understand why this was downvoted. Can someone explain?"
] |
[
"Does the ionisation of an atom via the decay of a radioactive element result in an atom of a separate element becoming unstable or radioactive itself?"
] | [
false
] | As above: For example- Would a gamma ray released from decaying radium result in a nearby carbon atom becoming radioactive itself due to it's ionisation? | [
"Ionization of an atom doesn't induce radioactivity (although it can result in the emission of secondary x-rays).",
"For example- Would a gamma ray released from decaying radium result in a nearby carbon atom becoming radioactive itself due to it's ionisation?",
"It's possible, but rare. Radiation transmuting a... | [
"There are many possibilities. If it's carbon-12 in the initial state, there are many possible photon-induced reactions. For example, the photon could knock out a proton, it could knock out a neutron, it could dissociate ",
"C into three ",
"He nuclei, etc."
] | [
"Thanks very much!",
"May I ask, in my example what would the carbon atom become then?"
] |
[
"Why does placing a cone infront of your mouth amplify the sound of speech?"
] | [
false
] | If you don't change the intensity of your voice, the sound still comes out louder when placing something like a traffic cone infront of your mouth. I would understand it if it's only louder in one direction, ie the cone is directing the sound infront of you, but it seems to be louder everywhere. | [
"It amplifies sound in the direction the cone is pointing. Ordinarily, the sound waves coming out of your mouth will spread out in a spherical pattern from the source. By placing a cone over the source, you redirect the waves into a much more focused area, thus increasing the intensity in that area at the expense o... | [
"This relates to the answer I gave ",
"here",
".",
"The easy answer is that the cone makes the transfer of the sound waves from your mouth to the surrounding air more efficient. It would be even more efficient with an exponentially shaped horn, like a bullhorn, or with a larger cone. For lower frequencies, a ... | [
"Well then why isn't it even louder when you talk through, say, a cardboard tube? Interference?"
] |
[
"How we define bacteria's species?"
] | [
false
] | By the definition I googled, you define a species as a group of organisms capable of interbreeding. So how do we define the species of bacterias, that just divide into two new organisms, instead of mating? | [
"In the olden days we defined bacterial species by their phenotypes, or how they looked and how they behaved. ",
"In the less olden days we sequenced the DNA of bacteria and clustered them based on similarity and called close enough clusters the same and different enough clusters, different species. ",
"In mode... | [
"If I remember correctly, that part of the genome is highly conserved, and so it's good at showing relationships between different genomes by the differences between them because the mutation rate is consistent.",
"Other parts of the genome can under go huge amounts of genetic change by normal mutation or by hori... | [
"Thank you for the answer but... why?",
"Why focus on subpart of the genome, rather then the entire thing, and why that specific subpart?"
] |
[
"What determines the lifespan of a species? Why do humans have such a long lifespan compared to say a housecat?"
] | [
false
] | null | [
"Here is a paper that suggests epigenetics plays a large role. ",
"https://www.nature.com/articles/s41598-019-54447-w",
"It is true that mammal size is correlated to heart rate, and both are correlated to lifespan. Most mammals get about 1 billion heart beats. Humans have managed to beat this by being more soci... | [
"Similarly, here is a new paper from Sinclair Lab also suggesting this (more specifically loss of epigenetic info). Came out a few days ago and people are still dissecting it.",
"https://www.cell.com/cell/pdf/S0092-8674(22)01570-7.pdf",
"01570-7.pdf)"
] | [
"The lifespan of a species is determined by a combination of genetic and environmental factors. Genetic factors include the presence or absence of certain genes that are associated with aging and disease, while environmental factors include access to food and water, exposure to toxins and pollutants, and susceptibi... |
[
"What is the smallest scale that gravity has been measured?"
] | [
false
] | I have read that there have been some experimental setups for measuring gravity ant the submillimeter range. What is the motivation for these experiments? How does one prevent interference from things like electromagnetism, etc? | [
"Roughly 100 microns.",
"One of the motivations of these experiments is to see if Newton's law breaks down at very short distances, which may be a sign of ",
"extra dimensions",
"."
] | [
"Really? 100 microns? That seems... Big. Maybe if I had liked my MEMS class better, I'd know where to get my Nobel. ",
"Edit: I suppose you are starting to deal with ludicrously small forces at that scale, though. Much smaller compared to everyday, relatable forces than 100 microns is compared to everyday relatab... | [
"Gravity is pretty weak."
] |
[
"Why specifically do these bottle lights in the Phillipines need bleach? Could they use another substance or does it have to be bleach?"
] | [
false
] | Here is a link to a photo of what I'm talking about. I am curious as to what the bleach specifically does to create this effect. Based on my limited knowledge, it seems to me like it just clouds the water and disperses the light better. If that is the case, could something else be used to disperse the light? On the ato... | [
"Isn't the bleach is used to inhibit algae or mold growth (in the water that's in the bottle)?"
] | [
"Exactly. "
] | [
"A question, based on my understanding. Mismatched punctuation. Apologies."
] |
[
"Does Heisenberg's uncertainty principle suggest that you can determine velocity and position to good precision if you don't know the particle's mass? Is there even any situation where that could come up?"
] | [
false
] | [deleted] | [
"Not in nonrelativistic quantum mechanics, in which mass is not an operator but just a constant, so that \"velocity\" can be associated with the momentum operator divided by the mass, i.e. all the uncertainty in v is due to the uncertainty in p. In quantum field theory the situation is a bit more complicated, becau... | [
"Neat, thanks."
] | [
"Don’t neutrinos exist in a superposition of mass states (neutrino oscillations)? Is it really not an operator?"
] |
[
"How are gamma rays artificially produced?"
] | [
false
] | null | [
"With laboratory gamma sources, or very high-energy gammas are produced using accelerators. For example HIγS, which uses inverse Compton scattering."
] | [
"Yes, a gamma knife uses a bunch of cobalt-60, and collimates the gamma rays emitted from its decays."
] | [
"Thanks for the reply, could that also be what is used in a gamma knife"
] |
[
"Would a helium balloon rise or fall on the moon?"
] | [
false
] | null | [
"Assuming it magically doesn't burst It would fall down."
] | [
"Yes, let’s assume is was inflated for a vacuum and would not be in direct sunlight."
] | [
"Helium balloons only float because they are less dense than the air surrounding them. With no air they would fall like anything else."
] |
[
"Could there be a computer powerful enough to run a simulation of itself?"
] | [
false
] | If we had a computer that could accurately model physical reality, would you be able to build a simulated version of a computer that could run programs, do calculations etc? Would it work? And if you could do that, it then follows that you could build a simulated version of the computer actually running the simulation.... | [
"It really has nothing to do with Godel's Incompleteness theorem, other than they're both arguments where we have a technique for producing a flaw in any putative example. You might as well compare it with \nthe proofs by contradiction of that the square root of two is irrational, or that there are infinitely man... | [
"It's not a question of power, it's a question of logic.",
"To be able to simulate itself, the computer would have to be more complex than it is. And if this were to be remedied by making the computer more complex, the result would be the same -- not complex enough to simulate itself. Did that make sense?",
"Th... | [
"Any computer can model itself if it has enough memory.. Its just a question of how quickly it can do it. Basically, all computers can be modeled as turing machines, and all turing machines can be made to run other turing machines if given their instructions."
] |
[
"How long does it take a voltage source to \"realize\" how much resistance that is opposing it."
] | [
false
] | In an electrical circuit, how long after the voltage source is connected does it "realize" how much current to produce based on the resistance it sees? | [
"The answer is \"it varies\". Do you remember Kirchoff's Laws and the Kirchoff Equivalent Circuit? Every non-perfect voltage source has a series resistance that represents voltage droop as you pull current from the voltage source. Similarly, every component and wire in your circuit has a parallel capacitance to ... | [
"Why did you neglect inductance? "
] | [
"I would respectfully disagree for certain values of \"circuit\". While shortness shrinks inductance, smaller diameters increase it. And while having thinner dielectrics grows capacitance, area decrease reduces it. When considering the current inrush to an IC during power transitions, inductance is just as impor... |
[
"How long could DNA last in space at absolute zero? Would it decay or is panspermia really possible?"
] | [
false
] | A friend mentioned that he read an article about the half-life of DNA in new zealand birds being around 500 years. It got me thinking.. would panspermia be possible if the DNA was near absolute zero given that none of the molecules are moving much and thus there would be almost nothing to cause the decay of the DNA... ... | [
"Low temperature (or no temperature) is great for preserving DNA, like most things. There is some mechanical shearing when it thaws, but at least in practical lab terms that's mostly just a function of how many times it's been frozen and thawed, not what temperature it got down to (at least assuming it doesn't go t... | [
"Space is not at absolute zero. That temperature would imply zero molecular movement and thus DNA would last indefinitely while at absolute zero. However, that temperature or lack thereof is not currently known to exist anywhere in the universe. This doesn't mean that DNA or its chemical makeup couldn't survive in ... | [
"Inside a comet?"
] |
[
"When an ISS astronaut goes out for EVA, do the airlocks conserve air, or vent it? What about airlocks on other space vehicles?"
] | [
false
] | I have read the layman articles on the Joint Airlock Module, but if this is answered in any I missed it. I am curious if the atmosphere in the intermediate chamber is pumped back into the station or vented out into space as the astronaut goes through. | [
"The Quest Joint Airlock works like this: an astronaut from either the U.S. or Russia enters the chamber, and the vacuum pump lowers the presure to 3 psi, and then to zero psi. After the air has been evacuated, the external door opens. There's also an equipment airlock that's used for overnight campouts to remove... | [
"The lower pressure is only used because they're going into a high oxygen environment (the suit). If the station was kept at a lower pressure, they'd need a high oxygen concentration which poses an obvious fire hazard (Apollo 1)."
] | [
"The problem with Apollo 1 was that when it was on the ground, it would have pure oxygen at full atmospheric pressure.",
"Worse, it was actually higher than full atmospheric pressure.",
"Apollo I was pressurized at 16.7psi to simulate the positive pressure environment during the plugs-out test.",
"In pure O2 ... |
[
"Why does butter last for weeks whilst refrigerated but milk spoils in a far shorter amount of time?"
] | [
false
] | null | [
"This is less a chemistry question and more a biology question. Regardless, the spoilage of milk and many foodstuffs depends heavily on bacteria rather than inherent chemical stability. Milk is extremely rich in nutrients like sugars, fats, and protein. This provides a fairly welcoming environment for bacteria to g... | [
"Wow. That was an incredibly thorough and easily understood answer. Thank you. "
] | [
"Also... Out of interest... Is there any reason why you know this other than good education? "
] |
[
"Proving infinity?"
] | [
false
] | null | [
"What do you mean by \"prove infinity\"? As it stands, this is quite meaningless."
] | [
"Isn't infinity just a concept? An idea? Instead of a fact?"
] | [
"So what do you mean by \"prove\" here? Generally, one writes down a ",
" about something, and then a proof of the claim consists of a series of logical deductions from our assumptions. There's no claim to prove here."
] |
[
"Is there a way to force yourself to dream about a specific something?"
] | [
false
] | null | [
"Oh I see. I'm not familiar with recent research on the topic and hopefully someone else with more expertise can chime in. I know there was older work that wasn't able to find any evidence for \"dream control\" methods (",
"Griffin & Foulkes, 1977",
"), but that's from a long time ago. Some more recent work has... | [
"Like ",
"lucid dreaming",
"?"
] | [
"Kinda, but before you can even go to sleep you ate able to kinda control where the dream is going."
] |
[
"Why does the math of physics (and science in general) work so well?"
] | [
false
] | It may seem nice that the laws of physics have integer exponents (especially for calculations), but why are they integers? Is there anything special about their being integers, or is it all just a lucky coincidence? As far as I know, the math behind science is just an approximation of the truth (although a good one), b... | [
"Nature cannot \"do\" calculus, no. Nature doesn't have to.",
"Calculus was invented by humans in order to quantify values already present in nature."
] | [
"There is a great essay about this called ",
"The Unreasonable Effectiveness of Mathematics in the Natural Sciences",
"It might be interesting for you."
] | [
"Something to consider: a lot of equations wouldn't make sense without integer exponents, because the units wouldn't work out. See ",
"http://en.wikipedia.org/wiki/Dimensional_analysis",
"Furthermore, a lot of the exponents in physics (for instance, the 1/r",
" in gravity and electromagnetism) are determined ... |
[
"Why is sodium flouride lethal but sodium cholride (salt) isn't?"
] | [
false
] | [deleted] | [
"Since any answer is better than no answer at all: Na is soluable in water, so it detaches from F and that leaves a bunch of F ions floating around in water. Now we know that F is very very reactive and so that amount of reactivity is harmful to our bodies."
] | [
"Because it can help strengthen teeth. Water is fluoridated at a very low level... so low that the tissue damage is negligible."
] | [
"Most treatment plants use ozone and/or chlorine. Fluoride would absolutely wreck their infrastructure and would carry significant safety risk... ",
"Fluorine is added specifically for tooth protection. It does not replace chloride in the teeth... it replaces they hydroxy group in hydroxyapetite."
] |
[
"Probability Question"
] | [
false
] | [deleted] | [
"First, you should check to see if your question has been asked before. In this case, it has, and frequently.",
"www.reddit.com/r/askscience/comments/mafn7/if_i_toss_a_coin_10_times_and_get_heads_each_time/",
"www.reddit.com/r/askscience/comments/maayw/alright_smart_people_of_reddit_help_me_finally/",
"But i... | [
"The odds of picking up a coin and flipping heads 100 times in a row are astronomically low. But if you have already flipped the coin 99 times and it came up heads every time, the odds of the 100th flip being heads is exactly 50/50. ",
"tl;dr - The previous 99 flips have no affect on the outcome of the 100th fl... | [
"It all depends on the question you are asking.",
"\"Bob has flipped a coin 100 times. All 100 times, it landed on heads. What is the chance Bob's next flip will land on heads?\" (50/50)",
"\"Bob has a coin. What are the odds he will flip it and land on heads 101 times in a row?\" (.5",
"Those are the tw... |
[
"Why is the iris coloured?"
] | [
false
] | So the question popped into my head - 'What does the iris do?' After a quick bit of research, I discover it's to control the size of the pupil - but that left me with another question - Why are they coloured? I understand they are pigmented, but WHY? Surely there is some reason? Thanks! | [
"It's melanin to protect the muscle from UV damage. More melanin (browner eyes) equals more UV protection. This is why people with heritage from high latitudes have lighter eyes and vice versa. "
] | [
"just to add on:\nblack and brown eye comes from melanin in the fronter iris epithelia, \nblue and gray is due to collagen in the stoma with little melanin in the fronter iris, \ngreen and amber a combination of collagen in the stoma and melanin in iris,\nred - little melanin in fronter and back epithelia\nviolet -... | [
"Wow, fascinating! :) Thanks, have an upvote!"
] |
[
"Is it possible to build a double-slit experiment at home?"
] | [
false
] | I really want to see this quantum effect for myself. I have a graduate degree is electro-mechanical engineering so I think I have the background to understand what I'm doing. I just want to know if and how it could be done on a budget with semi-commonly-available materials/equipment. If this is not feasible, are the... | [
"Get a small piece of glass, like a microscope slide and a candle, put the candle under the slide to get it nice and black, but be careful as the heat can break the slide. Get two razor or scalpel blades, hold them together against each other and drag across the soot. You should now have two slits with width apart ... | [
"You're an engineer, aren't you?"
] | [
"You need two things: A diffraction grating and a laser. Point and shoot. The double slit is a very specialized version of the diffraction grating because there are only two lines instead of an infinite number."
] |
[
"Is there a minimum mass required for something to have gravity?"
] | [
false
] | To put it another way, why don't we see particles of dust orbiting bowling balls? | [
"In space, these types of things can happen. But it would be possible to calculate the velocity for orbiting such an object. ",
"Here you go"
] | [
"No, but if we consider the force provided by a bowling ball (10 kg, approx) about 10 cm in radius, we can calculate the gravitational acceleration to be about 10",
" m/s",
" . For a 1 mg mass orbiting around it, it must have a tangential velocity less than about .1mm/sec. So considering that most things move f... | [
"Before I start I think it's important to point out that all atoms in the universe are attracted to each other, but the force attracting the two masses is directly to proportional to the product of the masses (i.e. mass of bowling ball * mass of dust particle and inversely proportional to the square of their separa... |
[
"Is the metabolic rate of a person who is doing \"hard\" mental work (ie, challenging math problems, reading novel in a second language, etc) measurably different from the metabolic rate of someone who is doing \"light\" mental work (ie, watching TV)?"
] | [
false
] | I'm not thinking "mental work = tons of calories burned," but it does seem that things that are mentally tiring would use more energy. | [
"Effectively, either no or a very little change, due to the high metabolic rate (20% of the body's total energy use) being from the brain already. This means that the extra work doing, maths, a crossword, writing etc doesn't shift the actual amount of work the brain does significantly upwards. In actual fact many r... | [
"In Robert Sapolsky's book, Why Zebras Don't Get Ulcers, he does claim that chess grandmasters expend more calories. Digging around the google machine a bit I found this:",
"The definitive study on chess players was carried out by the physiologist Leroy DuBeck and his graduate student Charlotte Leedy. They wired ... | [
"I have another question: when we do heavy manual labor or exhausting athletic exercise, does the brain burn significantly more calories?",
"Another question: have we detected any specific zones of the brain with increased energy consumption during specific tasks? I once had to do some maths for a few hours non s... |
[
"What propels light?"
] | [
false
] | Just curious, I was thinkin about it on the car ride home while passing under a stop light. | [
"Space is permeated by an electric field and a magnetic field, which - and bear in mind this is a gross oversimplification - describe how electrical and magnetic the Universe is acting at any point in space.",
"In the case of light, a change in the electric field causes a change in the magnetic field just ahead o... | [
"I would like to clarify things regarding the statement 'light propels itself'. This makes it sound as if light is completely independent and can move at free will.",
"The energy for light to begin its motion has to come from somewhere. In the case of the stop light for example, the energy is provided from the ... | [
"I could try, but for both our sakes I'd rather link to ",
"this legendary explanation."
] |
[
"So can anyone explain this p≠np? thing or why its so important?"
] | [
false
] | Just a college student who heard about it a few days ago. I don't know the first thing. | [
"I'll try to give as quick and readable an explanation as possible (without getting into deterministic and nondeterministic finite automata).",
"Basically P versus NP is asking the question are some problems fundamentally harder than other problems, or are we just bad at coming up with clever ways to solve them? ... | [
"The problem of P=NP is not to create a non deterministic turing machine (which really is a purely theoretical construct), but to create an algorithm on a normal turing machine to solve the problems in polynomial time. Once you have that, you have your pick of the litter of turing complete computers and languages t... | [
"Intuitively, it seems almost obvious that P != NP. Something a motivated college student should be able to prove in a page or two.",
"But, alas, it cannot, and despite the effort of some of the finest minds in computer science, it has eluded proof for decades. So it is interesting for that reason alone.",
"W... |
[
"Are swimming pools breeding chlorine-resistant organisms?"
] | [
false
] | Like the overuse of antibiotics. Are we breeding super microbes through the use of pool chlorine? | [
"If you think of microbial resistance in human terms, it makes more sense. If you send out a plague that kills a lot of people, some will survive and will likely be more resistant. The plague is a very specific, complicated way of killing an individual. Now if instead, you threw every human in lava, nobody would... | [
"They probably evolved gradually. Like flying, it didn't evolve by everyone jumping from the cliff (into the lava). The point is, if you apply extreme measures there is no time for anybody to evolve because everybody dies. Evolution can only happen if there are survivors who can still reproduce. ",
"Even with ant... | [
"What about extremophiles? Didn't ",
" evolve to survive extreme environments? Why can't this be possible with something like chlorine?"
] |
[
"Why and how do neutrons affect nuclear reactions?"
] | [
false
] | null | [
"sorry if I was a little vague. How does different isotopes affect nuclear reactions differently? Why do they have different effects?"
] | [
"What do you mean?"
] | [
"For chemical reactions, it's all the electrons that matter. And the number of electrons is determined by the number of protons. The neutrons are comparatively less important in chemistry.",
"However in nuclear physics, protons and neutrons are equally important to the structure and reactions of nuclei.",
"The ... |
[
"By what mechanism is HIV transmitted from Mother to Child?"
] | [
false
] | [deleted] | [
"There is little known about why the placenta does not transmit the disease. It's not necessarily that it blocks the entrance of HIV, as NLM endorses the fact that the fetus is exposed, but the fetus does not become infected.",
"\"However, the protective effect of cesarean section (25) coupled with the presence o... | [
"The mother donates the WBC's with HIV inside it's genetic complex, as HIV is a endogenous virus. All WBC's with HIV don't have a antigen complex that is able to be recognized by the human body, because it is a virus capable of mutation at a fast rate. The mother donates her T-cells to the child with the unrecogniz... | [
"So mother to child transmission occurs in three ways... \nDuring pregnancy – the foetus is infected by HIV crossing the placenta.\nDuring childbirth – the baby is infected by HIV in the mother's cervical secretions or blood. (this is the most common method and that is why if the mother is not on medicines she is a... |
[
"Does improving certain mental abilities limit others similar to how physical abilities do?"
] | [
false
] | A professional marathon runner is never going to be the weightlifting world champion, but is a professional chess player limited at language learning for example? I hope the flair fits. | [
"So, basically, yes. But youre not thinking broad enough. ",
"You can teach your brain HOW to look at things. If your always looking for a fact based solution, or if you only ever learn about 1 specific subject etc....then your brain is going to learn that there is only 1 way to do everything, but its going to be... | [
"No limits of that sort. There are practical limits in number of hours per day for a person to dedicate to practicing or memorizing something, but there aren't limits or cross-conflicts to neural development.",
"Knowledge can be broadly classed as:",
"\"Declarative knowledge\": something that lends itself to b... | [
"It also would depend on how mentally flexible the individual is in applying their knowledge or adapting their mental models to another discipline. For example, a classical musician may be extremely proficient at sight-reading (performing a piece of sheet music without practicing), but experience difficulty improvi... |
[
"What are the risks of introducing backdoors into a cryptographic function? Can you secure said backdoor with another unique function?"
] | [
false
] | Politics aside, I am curious why even put backdoors into a standard function if it allows an adversarial system to have an attack vector. Rather than attacking the function, why not just attack the backdoor? I could see securing the backdoor cryptographically, but would that allow the adversary to see any unique about ... | [
"What are the risks of introducing backdoors into a cryptographic function?",
"As you point out, the backdoors could be used by adversaries. If the adversary knows what the state knows, then it is trivial. Sometimes, a state (or a specific branch thereof) could BE the adversary.",
"Can you secure said backdoor ... | [
"Meaning, will they see that there is a part of the function that is unique to the rest of the hashed string?\nWhat risk does a state posses when they introduce a backdoor into their encryption standards/functions?",
"I think I understand it. The risks are simple: if the backdoor leaks, it's going to come to mass... | [
"To address your last question: The major risk of introducing any security backdoor, cryptographic or otherwise, is that you have added an additional security reliance: Security through Obscurity.",
"Someone, somewhere has access to this backdoor. The method of utilizing it must be replicable and reliable, otherw... |
[
"What's the evidence that water vapor is gaseous?"
] | [
false
] | I had a discussion recently with someone who claimed that water vapor below boiling point was impossible, and that evaporated water is really tiny, tiny droplets of water, not single molecules. Can someone provide some experimental ways we know that it is single molecules and not droplets? | [
"that water vapor below boiling point was impossible",
"This is patently false and said by someone who obviously doesn't understand thermodynamics nor the process of evaporation. Now water vapor ",
" condense into little droplets, this is for instance what happens over a pot of boiling water and why you can ",
... | [
"Investigating the thermodynamic energies of single molecule escaping from the surface of a liquid vs. an entire droplet of water would generally disprove the idea that evaporated water is actually tiny droplets--tiny droplets of lots of molecules escaping coherently from a solution is not energy-favorable. Tiny d... | [
"Yeah, of course he's wrong and uneducated. He was just claiming that there is no real documented evidence of single-molecule water vapor below boiling point. ",
"I also offered to him measured diffusion rates, which are highly mass-dependent; measured chemical reaction rates, which would be different if water is... |
[
"Why does hot water clean better than cold?"
] | [
false
] | null | [
"Take a look over ",
"here",
" and ",
"here",
"."
] | [
"Simply put (trying to remember from chemistry in high school so someone please correct me if I'm wrong) it's because of how atoms react to temperature. When atoms are cold they move very little but when theyre heated they get agitated and vibrate, shift, etc. This makes stuff like crusted food on dishes easier to ... | [
"Thanks."
] |
[
"Can you tell a right eye from a left eye like you can with bones?"
] | [
false
] | I know that with bones, you can tell which side of the body it came from due to its morphology, but an eye is ovoid. If someone were to find just an eye, could they be able to figure out which side the eye came from? If so, what indicates the difference? Or is it too difficult to tell because of its specific shape? | [
"The six extraocular muscles have a left/right pattern, especially the inferior oblique muscle with comes from the side of the nose and runs down and around the bottom. So, you can deduce left/right from the muscle attachment points in the eyeball."
] | [
"Not to mention that the optic disc is not central, so you should be able to orientate the eye appropriately."
] | [
"Oh yeah. No idea why I remembered the muscles and forgot that."
] |
[
"Determining the spin of a electron."
] | [
false
] | [deleted] | [
"A few more things: the 2P level does have 3 orbitals, and they are: ",
"; remember that there are 2 quantum numbers that start with m:",
", I believe that you are referring to the Ml quantum number and those for the 2p orbitals are: -1,0,1. Yes, you are correct when stating that Hund's rule required you to put... | [
"Those elements are not in the d orbital so that right there could be your problem. They are in the 2p orbital. "
] | [
"Those elements are not in the d orbital so that right there could be your problem. They are in the 2p orbital. "
] |
[
"What is actually expected to be discovered in Lake Vostok?"
] | [
false
] | I recently read a couple articles on Lake Vostok and was just wondering, what scientific discoveries are actually expected to be found? Like are scientists looking for earlier life forms, studying the water quality from earlier times? or is it just a mixture of a lot of different things? Edit: Thanks to everyone for yo... | [
"They are hoping to find life down there. Life which has been isolated from the surface for ~20 million years and has had all that time to figure out interesting new strategies for survival. "
] | [
"Most (almost all) food webs depend on photosynthesis to begin the cycle. The classic idea of the grass gaining energy from the sun, the deer eating the grass, the wolf eating the deer yada yada.",
"There is a thing called chemosynthesis, where autrotrophs (organisms who basically begin a food cycle) gain their e... | [
"They were hoping to find organisms that showed proof that life could sustain in situations LIKE those found at Lake Vostok. It's more important to realize that the operations that happened at Lake Vostok were testing the possibility of drilling through deep ice in order to study the liquid water below. ",
"That ... |
[
"Could an entire pool table be potted in one shot?"
] | [
false
] | [deleted] | [
"The fact that there are infinite inputs does not imply that all outputs are possible. It may be possible to find an angle and power which would theoretically result in all of the balls ending up in a pocket, but it's possible (though I would be surprised) that there's no angle you can hit it from that will give th... | [
"Arguing this in a purely idealised/mathematical way is a bit difficult I believe. For example in an idealised 9ball setup and break, the central ball (9) would not move at all from the initial impact of the cue ball. It could only be moved from balls ricocheting off the cushions.",
"Just looking at actual 9ball ... | [
"If we are disregarding all kinds of friction this makes sense, yes."
] |
[
"The new Orion spacecraft seems remarkably similar to the Apollo spacecraft in design and function. However, a return to lunar orbit isn't planned until after 2020. Why will it take so long to test and implement the new spacecraft if it is based on technology that was functional 50 years ago?"
] | [
false
] | Originally posted this to AskReddit. Sounds like it belongs here. I recently got back into space exploration history, and started reading up on the planned Orion spacecraft. The design seems remarkably similar to the Apollo spacecraft. One thing I don't understand is why will it take 10 years to develop a new craft tha... | [
"One of the issues is that it's not just the equipment that needs to be rebuilt, but the equipment to build the equipment (and sometimes the equipment to build the equipment to build the equipment etc). There is also the issue of money: NASA in the 60s had up to eight times the relative budget that it does today."
... | [
"In addition, a space program is more than the launch vehicle and spacecraft. The infrastructure required to support this equipment and the training to operate it isn't something that can be replicated overnight."
] | [
"We could re-create the Apollo program, but it's not likely that we'd want to. The Orion spacecraft bears a strong resemblance to Apollo because the shape of the Apollo spacecraft was very ideal for expendable launch missions, and this is exactly what Orion is intended to do. It is not, however, a carbon copy of ... |
[
"Would wires made of anti-matter have the same electrical properties?"
] | [
false
] | Would the right hand rule still apply or would it be the left hand rule? Would electricity be propagated with positrons and would this change how the magnetic fields would be generated? Is it the same, but opposite or the same in general? | [
"All the same rules and formulas would still apply; with the definitions we use, a current going in a given direction can be the flow of positive charges in that same direction, or a flow of negative charges in the opposite direction. Or both! Magnetic fields are the same for the flow of a positively charged an... | [
"Dirac was working on relativistic quantum mechanics, combining quantum mechanics with special relativity. Considering the energy equivalence relation, he realized that there should be infinite negative energy levels, so electrons with positive energy states should fall towards negative infinity. They obviously don... | [
"One could argue that all of quantum physics fall in that bucket of \"experimental results explained mathematically\". The ",
"ultra-violet catastrophe",
" was an issue in the late 19th century physics, where established theories predicted dark body radiation to approach infinity as the wavelenght decreased, wh... |
[
"Do we keep our atoms as we age?(more questions inside)"
] | [
false
] | [deleted] | [
"Is saying that tissue doesn't regenerate really the same as saying individual atoms aren't ever replaced, though?"
] | [
"You are correct in assuming you gain atoms through ingestion, but also through respiration.",
"There are likely atoms that stay with you for life, or close to it.",
"An example would be ova (egg cells in women's ovaries) which go into suspended animation in a fetus. Some of them stay in that state for decades... | [
"1) Yes, for instance those in the corneas of your eyes, which is one bit of tissue which isn't regenerated. ",
"2) The molecules making up your body are continually broken down and reconstructed in cells. "
] |
[
"Have a couple of questions after watching a Lawrence Krauss talk"
] | [
false
] | Link to original talk: 1) Is that flat universe model widely accepted? 2) Does that necessarily mean that the universe started out of a quantum event as opposed to the big bang? | [
"I'm just guessing here, but I'd be willing to wager that you're imagining a \"quantum event\" as something very small, and the \"Big Bang\" as something very, well, ",
"It's not that simple."
] | [
"So I'm making an unnecessary distinction? "
] | [
"I don't know how to answer that in this context.",
"What I mean to say is that the phrases \"quantum event\" and \"Big Bang\" carry with them entire ",
" worth of context. People literally dedicate their whole lives to trying to understand those two ideas."
] |
[
"Why do some vaccines like rabies or tetanus \"wear off\" after a few years?"
] | [
false
] | [deleted] | [
"Most of the replies so far have been useful but they fail to accurately answer your question.",
"Tetanus vaccine is a toxoid vaccine, which means you're inoculated with an inactivated toxin from the bacteria Clostriudium tetani. Inactivation of the toxin is usually accomplished via formalin washes. Due to the we... | [
"If you don't run into a version of that disease, your body decides that it is no longer a threat, and it stops producing antibodies for it. ",
"Most (if not all) of the \"lifetime\" immunizations work for one of two reasons:",
"You are constantly exposed to it (chickenpox and its ilk)",
"You are never expose... | [
"That's rather over-simplified. It's not so much that Plasma B-cells stop producing antibodies as they become less proliferative (i.e., less likely to reproduce) without a cell-cycle signal due to antigen presentation. Recent findings have suggested that these Plasma cells never entirely go extinct either; long ter... |
[
"If two people held a string stretching from one side of the universe to the other, would it snap due to the expansion of the universe?"
] | [
false
] | null | [
"Yes. There is a real tension on the string from the expansion."
] | [
"This question must come up in String Theory all the time, hey?"
] | [
"Tension from expansion is important for cosmic strings, which are treated with a similar formalism to fundamental strings in string theory.",
"Same thing also appears when formulating string theory on a de Sitter (exponentially expanding) background."
] |
[
"What is the \"Earth-light\" that illuminates the dark side of the moon?"
] | [
false
] | Is it artificial light from the surface of earth or is it naturally occurring? From where I am right now (Peterborough, Ontario at 9:45pm) I can clearly see the dim sphere of the dark side of the moon, wrapped in a waxing crescent. My understanding is that the earth is lighting up its own shadow on the moon. Is this co... | [
"It's reflected sunlight. Artificial light isn't nearly bright enough to noticeably illuminate the Moon.",
"My understanding is that the earth is lighting up its own shadow on the moon.",
"You're not seeing the Earth's shadow on the Moon. The Moon is partially dark because the half that faces the Sun isn't nece... | [
"The \"dark side\" of the moon isn't really \"dark\" it's just the side we never see because the moon is tidally locked and one face always points towards the earth. "
] | [
"I see, thank you. I was I was confusing the phases of the moon with a lunar eclipse it seems. ",
"I think part of my question still stands though- how exactly does sunlight get to the side of the moon ",
" facing the sun?"
] |
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