title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How much commonality is there between 'human' medicines and medicines for use to treat animals?"
] | [
false
] | I expect that dosages will vary based on things like body weight or metabolism, but are the same medicines typically used for both humans and other animals, or not? | [
"There are a lot of different kinds of animals, so it is hard to answer with any specificity but generally a lot of medicines are able to be used interchangeably between mammals. Anesthetic agents, antibiotics and antiparisitic agents are just the examples I can think of off hand. Chemicals, however, can't always b... | [
"There is significant commonality, but you are right in thinking that size and metabolism are variations determining what is used.",
"Metabolism (more specifically ",
"xenobiotic metabolism",
", that of breaking drugs not \"how much energy you use\" type metabolism) varies between species. We all have differe... | [
"Hello Veterinarian in the USA,",
"If you like answering questions, you should consider ",
"applying for flair",
"!"
] |
[
"Moving to new laboratory! What do I need?"
] | [
false
] | Hey folks, I work in a biophysics/neuroscience lab, and we are moving to a new building. It is approaching last minute request time for furniture and hardware. What do you guys find particularly useful that is not standard issue? | [
"Things like safety glasses box near the entrance to the lab (preferably outside), glove dispenser might get forgotten.",
"Don't know what kind of stuff you would be doing but you can never have too many retort stands and clamps."
] | [
"Label maker. This is key."
] | [
"I like a buddha statue for this, it accepts donations and, after a few months, buys beer for the lab."
] |
[
"Do all organisms breathe, and if so, why? What is it about oxygen that makes it so important for life?"
] | [
false
] | null | [
"Oxygen is actually toxic to some organisms, due to it being highly reactive. These bacteria, called obligate anaerobes, usually live isolated underground.",
"However, all higher organisms require it to live. This is because, due to its reactivity, it can be used to extract 18 times as much energy from a sugar ... | [
"Note: I've just finished highschool and am starting University this year, so please forgive if I make any silly mistakes.\nFirst of all, oxygen is used in respiration to release energy from stored energy (in the form of fats, proteins and other organic molecules (ie. Molecules based on chains of carbon atoms)). Ce... | [
"I can only answer part of your question.",
"Not every living thing breathes, but most do. Creatures that don't require oxygen are called ",
"anaerobic organisms",
", the most common example being yeast."
] |
[
"Why is it difficult to breathe when the wind is blowing in your face?"
] | [
false
] | Examples of when it happens include riding a bike at 30+ mph or sticking your head out the window of a moving car. | [
"I think it's because when fluids are in motion, they are at a lower pressure (Bernoulli's principle). Since you essentially decrease the pressure in your lungs to inhale, you can't get as much air if the pressure differential with the outside isn't as high.",
"This should also partially explain why it's harder t... | [
"From my experience (as a back-country skier) high altitude makes it harder to catch your breath, but not to breath mechanically. I have also noticed (as negativeK has) that when facing the wind it is harder to pull air into your lungs from a more physical standpoint and is not really similar to the effects of alti... | [
"It would be decreased by d * v",
" /2, where v is the velocity of the fluid and d is the density.",
"\nThe whole effect could be simplified like this: normally, we decreased the lung pressure to \"inhale\". The breath stops when pressure inside and outside is balance. As the wind rarely blows straight into the... |
[
"How does being born blind or deaf influence the way you think?"
] | [
false
] | null | [
"DeafBlind people learn tactile sign language. So they think in that language. ",
"If you're interested in something more deeper, there have been studies that show hearing people are able to memorize 7 short bits of information (like a phone number) in only one direction, while Deaf people are able to memorize ... | [
"Since there are areas of the brain specifically predisposed to process visual and auditory information, when someone is deaf or blind, they will often recruit these non-utilized regions of the brain for other functions. For example, when a blind person reads brail, the language regions of their brain will light up... | [
"In addition, people with vision loss can utilize their hearing and sense of touch better, although that isn't something that \"naturally\" occurs. It happens because rehabilitation instructors teach them how to use that information. When using a white cane (I'm an instructor who teaches how to use a white cane), t... |
[
"Can you breath ozone?"
] | [
false
] | From what I know, we respirate by breathing oxygen (O ). But I am curious as to wether or not we can breath oxygen in other forms such as ozone (O ) or plain ol' O. | [
"Individual oxygen atoms can't exist as a free gas, they are far to reactive and will bond to literally whatever they hit first. The only place atomic oxygen can exist is in the near vacuum of outer space where they don't hit anything for a long time.",
"O3 is considered to be an environmental pollutant, and can ... | [
"Ozone is very unstable as far as molecules go. Yes, you can breath it. However, when you do, the O3 will give up an oxygen molecule, opting for the much more stable O2 molecule, with the free Oxygen, now known as a free radical defined by its high reactivity can now react with lung tissue or DNA. "
] | [
"To expand on this, ozone is a far stronger oxidizing agent than O2 (diatomic oxygen.) As a result, it will react with compounds in the body, oxidizing (damaging) them and releasing O2."
] |
[
"What would the light-dark cycle be like on a tidally locked moon of a gas giant?"
] | [
false
] | null | [
"Depends on where you are.",
"The moon would experience a night and day cycle equal to it's orbital period around the moon. If you were on the side of the moon facing the gas giant, you would also have very bright nights whenever they are illuminated by the gas giant. The phase of the gas giant, and how it lights... | [
"Closer by life would not be possible. So it would have to be a moon like Titan. Not sure I think Titan is about 16 days? Maybe 500 hours is a bit on the long side.",
"THis kind of radiation doesn't blow away. It's charged particles. No isotopes. It just impacts once a revolution, when the planet is on the aft si... | [
"(Hemisphere Facing the gas giant)"
] |
[
"How does gravity work in Quantum Field Theory?"
] | [
false
] | I was watching this pretty cool video: and it contained a lot of interesting information about the nature of particles and how various fields interact with one another. My question is, given the best information available at the time, is there a theory on how gravity works within Quantum Field Theory (QFT)? I guess a secondary question would be, considering the interaction of say the Higgs field to add mass to an electron, how would one expect a gravity field to interact with a photon? I'm guessing such an interaction to exist given the ability of gravity to bend light; though I've a sneaking suspicion that something's wrong in my understanding. Thanks in advance for any information. | [
"QFT can describe gravity. But the theory, massless spin-2, is not renormalizable. That is, when we compute processes with several loops the theory gives infinities that we can't get rid of. "
] | [
"Because photons are massless and travel at lightspeed. Electrons are massive (due to their interaction with the Higgs-field) and always travel at speed strictly lower than lightspeed."
] | [
"In the language of quantum field theory, gravity is a spin-2 massless interaction. You can consider photon-graviton scattering with a lot of calculations that aren't always solvable, like ",
"here",
"."
] |
[
"How small can we go in terms of the sub-atomic structure?"
] | [
false
] | A lot of people I know don't realize that we've gone past the atomic level in science. My question is, what is the smallest particle that we've found so far? | [
"Our current \"standard model\" is 16 particles that are each fundamental, indivisible particles. ",
"Here's",
" one of our sciencefaqs that goes into a lot of detail about all the particles and forces."
] | [
"In classical optics, the ",
"diffractive limit",
" gives you a maximum theoretical resolution that is on the same order of magnitude as the wavelength of the light. So with visible light, one cannot resolve objects or details much less than ~200 nm.",
"In particle physics, the wavelike nature of quantum part... | [
"Seventeen, if you grant the Higgs honorary status. And eight of those go away if you consider the quark and lepton generations to be aspects of the same thing, which is not a totally unreasonable stance to take. Especially the neutrinos."
] |
[
"Why is the placebo Vitamin-C in this COVID-19 clinical trial?"
] | [
false
] | null | [
"But if the dangerous drug is no better than the harmless vitamin C, why would they want to use the harmful expensive drug, instead of the cheap harmless thing they can buy in bulk at a Costco? Surely if you’re going to introduce a new drug, you’d want it to be ",
" than something that’s already available? Isn’t ... | [
"Ok so I know mother jones is a pretty terrible source for this sort of this but it’s what I found the quickest. Put simply, the placebo chosen has to mimic the drug as closely as possible in aspects like after taste, color and consistency while being as physiologically inert as possible. Typically these studies wi... | [
"Are your friends claiming that vitamin C is ",
"? Because if their argument is that vitamin C is not a placebo because it’s good for you, then it’s harder for the vaccine to look good, because it has to be better than placebo to “pass” the clinical trial. Isn’t that what they’d want? ",
"I could understand it... |
[
"Is everything in the milky way orbiting the supermassive black hole in the centre?"
] | [
false
] | null | [
"Sort of... The black hole in the centre only makes up a tiny percentage of the mass of the galaxy. We're really orbiting all the mass of gas and stars and dark matter inside the Sun's orbit around the Milky Way. We are orbiting the black hole because it happens to be in the middle of this mess, but if you removed ... | [
"Otherwise known as the galaxy's barycenter."
] | [
"The black hole in the centre only makes up a tiny percentage of the mass of the galaxy.",
"To put some numbers on this: The mass of the central black hole is a few million solar masses, while the mass of the galaxy is about a trillion solar masses."
] |
[
"How do we know that the Milky Way is a spiral galaxy?"
] | [
false
] | Is it an educated guess? Or was it actually worked out? If so, how? | [
"Looking at the Milky Way galactic center we see a long thin strip which suggests a disc shape. The gas fraction, color, and dust content of our galaxy are spiral-like. Through studying the motions of the stars and nebula within our galaxy which are rotational and not random motions. As we began to take this inform... | [
"There is a variety evidence that support this. Just one of the more simple and direct observations comes from just looking up at a really clear night sky like ",
"this",
". What you see here is some of the gas and dust in our Milky Way. It clearly has a very flat, disk-like structure which supports the idea th... | [
"Yes, in the same context as gravity, Newton's force laws and electromagnetism are theories. Don't confuse the word \"theory\" with \"random guess\". Like I said, there is a lot of evidence to support that we live in a spiral galaxy and likewise a lot of evidence to support that we don't live in an elliptical or ir... |
[
"I believe I can feel EMF energy from cell phones. Help me design an experiment to test this."
] | [
false
] | I recently had a discussion in about EMF sensitivity. I believe that I am able to feel an active radio transmitter near my body. There is a physical discomfort I get from having a phone in my pocket for any length of time. Also, I get headaches from talking on a cell phone for too long. However, I am aware that the brain is capable of playing tricks on itself. I would like to test my EMF sensitivity in a blind experiment. My plan is to take two android phones, and have a friend randomly put one into airplane mode and set the other to transmit data over 3g. I will then hold the phones in either hand for a length of time until I can feel which one is transmitting. I will then repeat this procedure several times, with my friend randomly switching which phone is transmitting, until I get a statistically significant answer one way or the other. I will not activate the screens on the phones, and my friend will not tell me which phone is set to transmit, so there will be no way for me to determine which is transmitting, aside from my claimed EMF sensitivity. I have a few questions before I run the experiment: Is there any app that will make a phone continuously transmit data over 3g? I want to make the contrast between the inactive phone and the active phone as sharp as possible. How many times should I run the experiment to get a statistically significant answer? I do not have two identical phones. My phone is an LG Optimus Slider and my friend's is an HTC Wildfire S. Both are running android. If the transmitting phone is randomly switched enough times, will this be a problem? Is there anything else that I should alter about this experiment or add to make it more thorough and scientific? I will post the results of the experiment once it is completed, and I give my word not to lie or alter the outcome. If there is enough interest, I may even take a video of the procedure. While it is my belief that I am in fact EMF sensitive, I would not be embarrassed to publicly discover that it is all in my head. Note: This was originally posted in . I am posting it here as well because it is more relevant. | [
"additional things to do: ",
"Don't hold them in your hand. ",
"(1) Leave the room.",
"(2) Have friend select which is to be turned on based on random number generator.",
"(3) Have friend place phones in identical cardboard boxes. You may want to add some additional sound insulation, too. The point is to bl... | [
"This would be perfect for our ",
"Science Fair",
"."
] | [
"youtube or a speedtest application. You can't set your phone to be a constantly-on emitter, that's against most regulations.",
"I don't know",
"most phones will transmit at roughly the same power at the same time. The output power of a phone is related to how crowded the network is, it's adaptive.",
"Get rad... |
[
"How does a single nerve (like the vagus nerve) independently control several different functions?"
] | [
false
] | I mean without activating/deactivating all the functions at the same time. | [
"Basically because the nerve is not a \"single entity\" in the way that it's not a monofilament, but many individual \"strings\" grouped together. As a result, each string (in fact these are axons, each one belonging to a different neuron) starts in a specific place and end in another specific place, and responses ... | [
"Can a single neuron send (possibly different) outputs to different places depending on the input?"
] | [
"I am tempted to say no, but as this is neuroscience I don't want to be absolutely positive it ",
" happens, unlikely as it sounds to me.",
"Basically the neuron, after activated, will send an electric current through all its terminations, affecting all subsequent cells. As the neuron usually carries a speciali... |
[
"Is there something that prevents you from getting do different colds/flu's at the same time, or does that happen?"
] | [
false
] | So if you get sick, your body builds up an immune response to fight it off. I'm wondering if this heightened immune response would make it more or less likely that you would get a second illness like that at once? So, does your immune response in its elevated state fight off a new bug more effectively - or is it so concentrated on the first illness that it's more likely to ignore the new bug? It's pretty hard to tell, when your sick, whether you just have one thing or more, but I've always assumed I just had "a cold" or "the flu". But maybe I've had more than one thing. Anyone know? | [
"Very well put, but this holds true only for the adaptive immune response and not for the innate immune response. Innate immune response is a more general fight anything type of immunity. This includes our phagocytic cells (which if called to an area of infection will eat just about anything there whether it's bact... | [
"You can indeed be infected by two different viruses/bacteria at once. As for whether your heightened immune response will help fight the second one, I don't believe it would because of the way viruses and bacteria are fought using antigens specifically for each pathogen:\n",
"https://www.youtube.com/watch?v=zQGO... | [
"Thanks for the elaboration. I had a feeling that some parts of the immune response may target general foreign bodies but I had no specific examples. The immune system fascinates me more every time I learn something new about it!"
] |
[
"*Physics* Can someone explain what exactly is \"Einstein's biggest blunder\"?"
] | [
false
] | [deleted] | [
"It was a blunder because Einstein changed his physics to match up with a certain philosophical notion he had in mind - that the Universe was static and unchanging - rather than listen to what GR (without lambda) was telling him, which is that a (homogeneous and isotropic) universe necessarily expands or collapses.... | [
"It only became apparent that we need the CC in the nineties (but with a different sign). So based on what was know at Einstein's time, its introduction was entirely baseless. It's bad science. He wanted to believe that the Universe is static so badly that he modified his equations to fit his ideal.",
"But in fac... | [
"It was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary, as he had based his theory on the idea that the univer... |
[
"I always hear that \"a cure for cancer\" is misleading, because cancer consists of a variety of different disorders, with no single cure. That being the case, are there any individual cancers that have been effectively \"cured\"?"
] | [
false
] | null | [
"The most dramatic gains have been made in childhood cancers. This includes acute lymphoblastic leukemia, acute myeloid leukemia, testicular cancer, hodgkin's lymphoma, and many others. ",
"Here is a graph",
" demonstrating the gains in 5-year survival rates for lots of common childhood cancers.",
"More rec... | [
"Getting a treatment option approved is an extremely long process. Most of the stuff you link is at the lab stage, so it needs at least four more main stages (working prototype, animal testing, small- and large-scale human testing) before it can start being used. That takes heaps of money and a lot of time, and eve... | [
"As a follow-up question:",
"It seems like every year there's a slew of new, novel treatments for cancer that get a big fanfare when they're first announced and then are never heard about again.",
"For example:",
"Gold nanoparticles",
"Cancer-targeting viruses",
"Carbon nanotubes as drug carriers",
"Can... |
[
"Do the large lakes of North America have a common geological/geographical origin?"
] | [
false
] | When I was younger, me and my dad were looking at a map of North America, when he pointed out that a number of huge lakes - including Great Bear Lake, Great Slave Lake, Lake Athabasca, Lake Winnipeg and the Great Lakes - seem to cut an almost linear northwest-southeast slash across the continent. He wondered why that was. Now I do too. Is this just a coincidence, or is there a common link between them that causes them to do this? I know there was once a large glacial lake in the area, could that have something to do with it? | [
"Yes, the Great Lakes, Lake Winnipeg, Lake Manitoba, Lake Athabasca, Great Slave Lake, and Great Bear Lake are all remnants of far larger lakes that formed when the Laurentide Ice Sheet retreated after the last glacial maximum (colloquially \"the last ice age\" although calling it that really bothers geologists and... | [
"Yes, continental glaciation for the Great Lakes. It was a place of heavy snowfall then, as it is now. The very thick ice gouged out the surface in some places (Great Lakes) and the debris it left in other places made a kind of dam that held back water. Other lakes, such as Minnesota's \"thousand lakes\", same thin... | [
"I’m by no means an expert but I know the Great Lakes were formed by a glacier so I would guess it’s possible the glacier was slowly moving in that direction and carving out the lakes along that same path. Again just an educated guess, I’d love for some one actually knowledgeable on the subject to also respond"
] |
[
"Why are Mexicans half as likely to develop/die from cancer than US/Canadian citizens?"
] | [
false
] | This question is based off 2012 statistics provided by the International Agency for the Research of Cancer It looks like the same is similar for other less-than-first-world countries. Is this reflective of reality or a product of dissimilar statistical sources? | [
"Part of the explanation may be that folks are dying of other things first. Also consider that available information can only include cancer that is ",
".",
"The rate, naturally, may very well be the same, they're just walking around oblivious to it. ",
"People need to see a doctor first for anyone else to kn... | [
"I don't think you understand. The surviving people are avoiding th cancer, BUT the people who didn't survive also avoided the cancer, by dying.",
"Cancer is measured as a percentage of total population. You could reduce the cancer rate to 0% if you just killed everyone before the age of two. That doesn't mean yo... | [
"My understanding though is that Mexico has the distinction of being the only country with a higher obesity rate then America."
] |
[
"How do we know the laws of physics we observe are universal?"
] | [
false
] | null | [
"This is a really important question and it comes up with some regularity here. The answer seems to be that we haven't observed any variance of physics across our observed universe. Thus if they are non-universal they must change very slightly over ",
" long scales. ",
"But it's part of the philosophical inputs... | [
"what I'd expect to see is something truly unexplainable in the measurement of distant galaxies. I mean since they seem to behave with the same physics as local physics, then there's almost no test you could do locally to answer the question."
] | [
"Well we observe dark energy pervasive through the whole universe... It's not something that behaves one way \"here\" and another \"there.\" It's just a new physical phenomenon. Another way of saying it is that the galaxies distant on our left behave the same as galaxies distant on our right, etc. It really seems t... |
[
"Why does the modern English language curiously lack diacritics compared to other languages that use the Latin alphabet?"
] | [
false
] | Why does it lack accent marks, umlauts, breves, etc. Or, are there other, lesser known languages with this alphabet that don't use diacritics? | [
"The most surface-level answer is because English uses digraphs extensively instead. Sounds like th, the other th, ph, gh (which used to be a specific sound), Sh, and vowel combinations like oo, ou, and x_e (where x is a vowel), take the place of what might otherwise be ç, š, ž, á, ö, etc.",
"English used to have... | [
"All true. I don’t think you can overemphasize the importance of moveable type here. Printers made a lot of choices—many out of convenience for themselves—that became standard practice."
] | [
"German uses many digraphs as well (ch, ph, eu, ng, ... ",
"Wikipedia has a long list",
"), but we still have umlauts and ß. The umlauts can be replaced by ae, oe, ue and ß can be replaced by ss, so we wouldn't need these four special letters, but they are used in German.",
"We even have a digraph using an um... |
[
"Cutting someone in half and they still live for a few seconds?"
] | [
false
] | You see it in movies all the time. Someone gets a blade through their entire body (abdominal area) fairly quickly, cutting them in half and they manage to be alive long enough to look down at the destruction, say something, then die. Is that even possible? I mean, their heart and brain are still fine so I guess it can be possible, I just think its such a traumatic thing that you'd die almost instantly. | [
"There was a case of a cop somewhere in asia that got severed in half and survived. He does miss most of his lower half of the body. I'll try to locate the article and the video.",
"EDIT:\n",
" THE VIDEO OF THE COP THAT GOT CUT IN HALF BY A BUSS "
] | [
"Yes, it is possible, and during the French Revolution, there were some doctors that were experimenting to see if the brain was still functional after decapitation by guillotine ",
"[1]"
] | [
"Interesting question! Apparently the technical term for being chopped in half is ",
"traumatic hemicorporectomy",
". ",
"I did a cursory search on Google Scholar for references; pretty much everyone seems to classify it as \"obviously non-survivable\" but I found one report of a similar injury where ",
"th... |
[
"Is there a known maximum for the number of elements, or might we keep discovering new ones forever?"
] | [
false
] | [deleted] | [
"It's not known, but current models tend to point to an element with ",
"173 protons",
" as a hard limit."
] | [
"Hey, I coincidentally asked the same question, and got more responses, ",
"check it out."
] | [
"(For OP's interest)\nLook up nuclear shell models for more on this. Follow links on what you find, if you wonder why this is. I would recommend as a good textbook (easy to read and well-written) \"Modern Nuclear Chemistry by Loveland, Morrissey, and Seaborg."
] |
[
"If I had a steel tube, say 2\" in diameter, vacuum sealed and 30,000' high and dropped a marble down it, would that marble create a huge crater bursting through the bottom into the earth since terminal velocity has been removed?"
] | [
false
] | null | [
"No. A marble of mass 5 g at a height of 10 km has a potential energy of mgh = 0.005 kg * 10 m/s",
" * 10000 m = 500 J, which is equivalent to the explosive power of about a tenth of a gram of TNT, which is quite small. In order to create even a small crater you need thousands of times more energy. Note that the ... | [
"If we take OP's example to an extreme, then the highest speed achievable by something falling towards Earth is escape velocity ( 11.2 km/s ).",
"At that speed, the kinetic energy of the marble is going to be about 313,600 Joules or 75 grams of TNT (that is also close to what the kinetic energy of a 1 ton car tra... | [
"No, you had it right the first time. ",
"/u/HeraticXYZ",
" misinterpreted your comment. Then you misinterpreted his."
] |
[
"How sure are we that Type 1a supernovas are 'standard candles'?"
] | [
false
] | [deleted] | [
"I'm not saying it's way off, but is it possible that it's some off?",
"Yes it is, this is an area of active research as there are no really good models of what exactly happens during a supernova. There has also been some recent research showing that there may be trends between things such as the metallicity of t... | [
"I'm not saying it's way off, but is it possible that it's some off?",
"Yes it is, this is an area of active research as there are no really good models of what exactly happens during a supernova. There has also been some recent research showing that there may be trends between things such as the metallicity of t... | [
"First off, what you're referring to is chandrashekar ",
", not limit.",
"White dwarfs are responsible for 1a supernovae. They essentially leech off a star it's in orbit with until it gets heavy enough to go supernova. This means that the supernova always occurs at the chandrashekar mass, which means all 1a sup... |
[
"If someone had a tattoo covering their entire armpit, would they still sweat?"
] | [
false
] | [deleted] | [
"Oh man that sounds painful."
] | [
"For science!"
] | [
"What happens when tattoo ink is injected into a lymph node?"
] |
[
"Is asbestos really that toxic?"
] | [
false
] | [deleted] | [
"Some types of asbestos fibers (crocadilite or something like that if i remember correctly) are very strongly linked to mesothelioma, a cancer of the serous membranes (usually pleura, but possibly peritoneum), and also a type of cancer that is exceedingly rare without a history of asbestos exposure. So, yes, it is... | [
"Everyone has a little asbestos in their lungs.",
"Interestingly, the toxicity comes from the structure, not the chemical reactivity."
] | [
"Asbestos is associated with ",
" exposure. Anyone working with it has an increased risk of Mesothelioma. 90% of Mesothelioma patients reported previous asbestos exposure.",
"Asbestos exposure may also lead to pulmonary fibrosis and can predispose to bronchial adenocarcinoma.",
"According to my ",
"clinic... |
[
"Why is Guatemala green during the International Space Station flyover video (link in comments)."
] | [
false
] | Many of you have probably seen the . While watching it I noticed something strange at 1:26. I've looked into it and I believe it is the country of Guatemala. If you look as they fly over the country there is a green hue to ALL of the lights in the country except for the largest cluster which appears to be the capital, Guatemala City. EVERY other light in the whole country has this green tint to it that I haven't seen anywhere else on the planet in the video. Here is a of the part I'm talking about with what I believe to be Tapachula, Mexico and Guatemala City marked. It does not appear to be a large lighting effect that happens to be hitting Guatemala during the flyover because if you look closely it literally appears to follow the borders of the country almost exactly. It's especially obvious because of that little tip of Mexico that protrudes down into Guatemala. That little tip is the normal yellow tint that most of the world's other lights have. The flyover appears to come from the north so the little tip of Mexico comes before Guatemala in the video. The obvious explanation is that Guatemala has some sort of regulations that cause their lights to be of a different type. I have searched online and found no such regulations. Certainly nothing saying that the entire country right down to the little villages on the borders has adopted such a policy. Even worse, the capital city appears to be the only part of the country that does not have the green tint. So it would have to be a massive countrywide lighting program that didn't affect the largest city in the country and their capital. | [
"Architect here. Most street lighting in the world has always used high pressure sodium lamps. They were relatively efficient but cast an ugly yellow hue (you've seen these everywhere). Advances in LED technology mean that we can replace these with even more efficient LED lamps. Guatemala is ahead of other countrie... | [
"I don't know the answer to this, but since it appears that so far nobody else does either, I'll venture a hypothesis: ",
"volcanic ash of the right size can scatter red light out and let bluer wavelengths through",
", so if there were a relatively recent eruption in Guatemala it could potentially cause the lig... | [
"Just to add a bit:",
"The emission spectrum from low pressure sodium vapor looks like this: ",
"http://upload.wikimedia.org/wikipedia/commons/3/3f/SOX.png",
"It's a very narrow band and looks very yellow. ",
"A white LED isn't actually white. Generally, a white LED is a blue or UV LED with phosphors that... |
[
"If I made a photomultiplier tube that was really long (imagine any length), would the cascade effect reach a point where a photocathode is forced to release all of its electrons? What would happen?"
] | [
false
] | I know the basic premise of PMTs..strike a photocathode with a photon, generate an electron, which then strikes another cathode that then releases two electrons, which then strike another cathode, releasing 4 electrons..and so on...If I continued this process for a really, really long time, would I eventually reach a point where so many electrons are striking a cathode that it basically gets all of its electrons knocked out? What would this do? | [
"I think the question is asking what the effects are of a very long dynode chain. I don't think it would affect the photocathode at all. The dynodes towards the anode and the anode itself might get damaged, depending on what they're made of."
] | [
"The extra dynodes are the amplifier essentially. This particular PMT is very old with a 10cm aperture. The bandwidth is also very high, we are looking for around 10,000 pulses to appear in a total time window of a few hundred microseconds, with a pulse width of about 20ns. If we use a 1MOhm termination we get a lo... | [
"If you release too many electrons you will burn the photo-cathode. Those materials are set up to be very sensitive, to easily release electrons due to particle or photon impacts. If you release too many too fast, it is essentially having too high a current flow and will cause damage. This is exactly what happens t... |
[
"If we develop Artificial life and AI, what will they classify them as? Will they use the current biological system? Will they modify it? Will they invent a new one? What do you think is the best thing to do?"
] | [
false
] | null | [
"A good home for this question is ",
"/r/AskScienceDiscussion",
".",
"Please see our ",
"FAQ."
] | [
"ok thanks. what exactly makes it more suited for that sub rather than this one?"
] | [
"Discussion is for opened ended, speculative questions. This for example isn't something that can be answered concretely. We can speculate what we ",
" do in these situations, but we can't say for certain."
] |
[
"To achieve the Theory of Everything we need to unify all the fundamental forces, one of which being Gravity. But why is gravity even considered as a force if it is experienced due to the curvature of spacetime. Isn't it a fictitious force?"
] | [
false
] | null | [
"Oh, of course General Relativity is not a theory that explains gravity fully. It doesn't work when quantum effects become relevant. It must be an effective theory, just like Newtonian gravity is an even weaker one.",
"Can Quantum Foam be the answer for finding the interactions of spacetime to get a ",
" intera... | [
"It doesn't matter if you call it fictitious or not: It is an interaction, it should have some description. We have one already that works well in most situations - general relativity. But this is incompatible with the descriptions of the other interactions, and we would like to find a way to consider all of them t... | [
"It is way more abstract than that and has nothing to do with bending wires or anything. It is simply another mathematical description of the electromagnetic force. ",
"Wikipedia has a short entry on it."
] |
[
"IS it possible to have matter (like atoms or even galaxies) in this universe expanding and getting away nearly speed of light?"
] | [
false
] | Having in mind the universe expansion and the speed up velocities of the matter in the universe checked by Edwin Powell Hubble and Milton L. Humason whats the real chance of all universe speed up and all matter be swallowed into the dark of the (nearly) speed of light? | [
"Yes it's possible, because although nothing can travel faster than light, there's a loophole. It really means, nothing can travel fast than light ",
". The expansion of the universe however, is not matter flying away from other matter, it is space itself expanding. So the matter in space is travelling slower tha... | [
"Serious question: Is there even a definition of speed outside space? When speed is measured by distance per time can it even exist if you are not in a space with measurable distances?"
] | [
"Nope. If you can't measure something, even in principle, then it's a meaningless concept. This is why space, time and matter are all interdependent. you can only measure 'speed' and 'distance' if you have a ruler (light) and something different from the ruler (matter). If you can't measure where something is, the ... |
[
"Does space-time have viscosity?"
] | [
false
] | it appears, to a layman like myself, that space-time acts exactly like a fluid. | [
"No; In the viscosity/fluid analogy, satellites would have to experience a net force at all times, slowing them down to some degree no matter which direction they travelled. Somewhat like the thoroughly debunked ",
"Luminiferous Aether",
".",
"A gravity-fluid flowing towards masses doesn't fit either, since ... | [
"There are some theories that model a local space as a kind of superfluid (meaning zero viscosity along with superconductivity) but its only really useful for understanding some of the properties of quantum systems."
] | [
"But why does frame dragging happen at all?"
] |
[
"Is there marble on the moon?"
] | [
false
] | Are there metamorphic rocks on the moon? Does regolith have a metamorphic counterpoint the way some earth rocks turn into marble? Are there gemstones on the moon that do not exist on earth? | [
"Absolutely not. Marble is a metamorphic rock made from limestone - which is a sedimentary rock made from the hard shells of marine animals. so to get marble we need both oceans & life on the moon. "
] | [
"This is the correct answer. I'd just like to point out that limestones are not ",
" made from the shells of marine animals (biogenic) but can also be directly precipitated from water if that water is saturated in calcium carbonate. Of course this doesn't change the answer with regards to the moon."
] | [
"A smash of that intensity contains enough energy to entirely melt the rock, so it will re-crystalize as an igneous rock. "
] |
[
"How would astronauts navigate directions in open space?"
] | [
false
] | On Earth, navigation has always been relative to something (either the shores of the seas/rivers, or the magnetic poles). But in open space, how would you navigate? Relative to what we already know (stars, solar systems, galaxies etc.), or the need for new system of navigation would emerge? | [
"Allow me to introduce you to ",
"XNAV",
". It's like a GPS for space travel, using the regular signals emitted from pulsars instead of satellites. Incredibly, it's accurate to within 5km, which is an extremely small uncertainty given the vastness of space."
] | [
"Assuming they aren't doing any near-light speed travelling it would be a simple matter of triangulation with known points of reference. Like their relative position in 3-space to the earth and sun etc. ",
"The on-board computers would be able to tally up distances and angles fairly well to give a good simulate... | [
"There's a lot of pulsars, that are quite easily identifiable based on frequency. ",
"You can also orient yourself relative to deep-space objects, such as other galaxies - unless you're going ",
" far, these will remain essentially fixed."
] |
[
"What happens when radio waves collide, or multiple sources broadcast on the same frequency?"
] | [
false
] | I know radio waves fall along the same spectrum as microwaves and visible light, and tuning into those frequencies with a device like a radio allows us to listen in on messages if you're within range of the source's broadcasting. What happens when a device is tuned into a frequency that more than one source is broadcasting in? Would it mash the sounds together, or just result in audio static? Does that mean that someone could play a bunch of noise on all available frequencies in order to drown out whoever is using those frequencies in broadcasting range? Please note, i'm not attempting anything like this, just wondered if it was possible or what would happen haha | [
"EM waves are additive, and hence so are the signals received.",
"The way this affects the final outcome will depend primarily on how the communication system is built. For instance, with AM or FM radio, the receiver outputs whatever signal is in the user-selected frequency band. Thus, in this case, both signals ... | [
"What happens when a device is tuned into a frequency that more than one source is broadcasting in? Would it mash the sounds together, or just result in audio static?",
"Depends on the transmission encoding.",
"With AM it would just mix everything, with FM or QAM or similar it'll just make a mess of noise.",
... | [
"The energy is additive. So yes, if you had the equipment and knowledge, it might be possible to make it so that radio broadcasts are effectively blocked. All frequencies? That is going to take a bit of doing and a bit of power. And be prepared to be detected fairly quickly too since it isn't at all difficult to pi... |
[
"What makes Hydrogen Peroxide/Iodine/Alcohol/etc kill germs?"
] | [
false
] | null | [
"There are different ways of killing cells. ",
"A very common one is to apply something called oxidants to them. Oxidants are basically just atoms or molecules that really strongly attract electrons. The oxidants then \"steal\" electrons from the compounds that make up the cell (membranes, proteins etc.) and dest... | [
"Hydrogen peroxide works well if you cut yourself because every living cell has an enzyme catalase which is a catalyst of decomposition of H202. it breaks down like that 2H202 -> O* + O* + 2H20 -> O2 + 2H2O",
"before O* meets another O* to create O2 it's super oxidizing and bacteria suffer form a ricochet of that... | [
"Hydrogen peroxide is cool - the only reason it's safe to use around humans is that it's so hideously toxic, that most life evolved mechanisms to destroy it long ago. It's a potent oxidizing agent, and readily breaks down into free radicals. Iodine is similarly a good oxidizing agent. Both more or less wreck up the... |
[
"Why is there steam after a hot shower when the water wasn't over 100°C?"
] | [
false
] | null | [
"It's not the visibility that defines vapour, but the temperature at which it exists. Vapour is a substance in a gas phase at a temperature lower than its critical point. For water, any gaseous H2O at temperatures below 374˚C is water vapour."
] | [
"Water vapor ",
" steam. If you can see it, it's called condensed water vapor or fog."
] | [
"Out pedanted. Good job. :)"
] |
[
"How are doctors able to control the blood in this gif?"
] | [
false
] | [deleted] | [
"Blood isn't going everywhere because they avoid cutting large blood vessels. You only bleed where you cut into a blood vessel.",
"On top of that, they can use local vasoconstrictors to keep small blood vessel from bleeding, and they can clamp medium and large blood vessels that they have to cut.",
"Finally, ye... | [
"Oddly enough, ",
"the pericardial fluid",
"."
] | [
"Serous fluids, made by the serous gland cells. They make it from raw materials supplied by the blood. They are specialized for this purpose. The pleura does a similar job for the lungs, and the peritoneum does the same for most of the abdominal organs."
] |
[
"Why hasn't The Asteroid Belt formed a planet?"
] | [
false
] | [deleted] | [
"The total mass in the asteroid belt is quite small - much smaller than any planet, even much smaller than Pluto. That means a lower gravitational attraction between the objects, and a much longer timescale for the collisions of them (longer than the age of the solar system). In addition, Jupiter perturbs the orbit... | [
"I'm not 100% sure, but I think it's because the Asteroid belt is hardly a belt. Asteroids in the belt are spread extremely far apart, about 2 million miles between each asteroid ",
"source",
"That's too far apart for the asteroids to attract one another and begin to collapse into anything considerable. Added w... | [
"Size does not affect gravitational acceleration. Jupiter affects small asteroids the same as large ones."
] |
[
"What effects are responsible for the light shows of helicopter blades?"
] | [
false
] | This post was motivated by an post: My question: Is or static discharge? Or do both happen in different conditions? First hand accounts of the effect from the previous thread (in ) adamantly proclaim static discharge over pyrophoric effects which seems to contradict most of what I can find. A helicopter will charge due to the rotor blades flying through rain, snow, ice, or dust particles. | [
"Turns out this only happens in ",
"sandy environments",
". The blades kick up the sand, striking it, and causing the sparks you see. "
] | [
"That's what I thought as well. People ",
"claming experence",
" have insisted otherwise. "
] | [
"Here is the reason I don't negate the possibility of static discharge.",
"When you rub a piece of wool over a plastic rod to charge it there comes a point when you hear a bunch of tiny sparks as you rub the wool across the rod. At this point the rod is charged and there is a balance between adding charge and the... |
[
"What does space consist of?"
] | [
false
] | I think this is basically a two part question. First, is what IS space? So you leave a planet, you're in the vaccuum of space. What's in it? Doesn't gas escape from planets? Where does it go? It must occupy this area so how can space be a perfect vaccuum? Second: What about space on earth? If you go down to the atomic level, what's in between the electrons / protons / neutrons? When you get down to the size of particles...what are they travelling through? | [
"Good question(s).",
"Space is rarely a true vacuum. Even in inter-galectic space there are some atoms floating around. In addition you have Quantum Fluctuations.",
"Quantum Mechanics posits a Euclidean Framework within which particles have position (Heisenberg uncertainty and Wave/particle duality apply). So f... | [
"The gases don't escape earth because gravity holds them down. That said, you get a better and better vacuum the further out you go."
] | [
"No one's mentioned the one thing that's ",
" in space, which is the cosmic microwave background (as well as other backgrounds of decoupled species, like the neutrino background and gravity wave background, which are as yet undetected). At every point in space there are photons, about 2000 in every cubic centimet... |
[
"Is there a reason or advantage that organisms are sensitive to light from ~ 380 - 740 nm, or is it just a coincidence of evolution?"
] | [
false
] | [deleted] | [
"In fact, there's a very good reason! On earth, we're sensitive to these wavelengths because those are the wavelengths at which the sun emits light most strongly.",
"This chart:\n",
"http://en.wikipedia.org/wiki/File:Solar_Spectrum.png",
" shows the distribution of the solar radiation by wavelength. You can... | [
"I've always been skeptical of this explanation. The visible spectrum of light isn't just special in that it's the light emitted most strongly by the sun, it's also special in that it passes freely through our atmosphere, but is absorbed/reflected by most solid matter. Take radio waves, for example, which pass thro... | [
"Another point to add: there's also animals sensitive to infrared radiation such as pit vipers. But infrared is harder to focus into an image and the photons are lower energy so harder to detect."
] |
[
"Are there any two species that are both a prey and predator of each other?"
] | [
false
] | Like a species that preys on its own predator. Edit: Or as said, | [
"This is quite common in fish, because most baby fish are tiny. For example, a bass is quite happy to eat green sunfish, but a green sunfish would eat a baby bass if it got the chance."
] | [
"I'm not sure if this is exactly what you're talking about, but diving beetles regularly feed on tadpoles. When those tadpoles grow into frogs, however, they have no trouble eating the diving beetles. "
] | [
"Many fish species are predators of juvenile members of their own and other species that were predators on themselves when they were juvenile.",
"We kill and sometimes eat crocodiles, and given opportunity crocodiles eat us. The same with some shark species."
] |
[
"Why is lead so effective at stopping radiation ?"
] | [
false
] | [deleted] | [
"Anything can absorb or scatter radiation. You just might need more of it than is practical in a given situation. Lead isn't exactly special, per se; it's just that heavier nuclei are better at absorbing electromagnetic radiation than lighter nuclei, and lead in its normal metallic state is quite dense, so there ar... | [
"Depleted uranium? It's less radioactive per unit mass than a handful of average dirt."
] | [
"NOW ONE OF OUR NUMBER HAS GONE BLIND FROM RADIATION!",
"My God, does dirt have no mercy?"
] |
[
"If I eat food off the ground, never wash my hands...pretty much expose myself to germs, will my body be able to better fight off germs/disease?"
] | [
false
] | [deleted] | [
"It's better than water and soap for killing bacteria. But living in such hyper-hygienic circumstances eventually weakens the immune system."
] | [
"It's better than water and soap for killing bacteria. But living in such hyper-hygienic circumstances eventually weakens the immune system."
] | [
"Yes. But be wary. Some species of bacteria can cause illness with ingestion of less than 10 organisms. Also, ",
", which lives on your skin, can also cause digestive issues when ingested. Say no to hand sanitizer; wash hands with water and regular soap when necessary. "
] |
[
"Does temperature affect the experience of taste?"
] | [
false
] | My coffee tastes significantly better when it is warmer compared to when it is room temperature. Beer tastes better (to me) when it is cold. Is this just preference built over time or is something else at play? | [
"Do you have any source for this? I'm not really buying the \"emitting\" logic based on molecule speed."
] | [
"Most flavor actually comes from smell. Hot food that has water vapor coming off it will carry a lot flavor in that vapor. ",
"Oils and fat also carry lots of flavor and need to be a minimal temperature to be in a liquid state that can readily impart flavor to your tongue and sinuses. Cold, solidified oils have a... | [
"Of course it does affect the taste. Molecules move faster when something is warm thus \"emitting\" more taste and smell. The only difference with your coffee and beer is that beer has more intense taste and is less pleasurable to most people at room temp. But i guess that part is purely subjective."
] |
[
"In Planck Units, why is the Coulomb constant set to 1 rather than the electric constant?"
] | [
false
] | I've been wondering this for a little while now, as in rationalized system (such as L-H units), the electric constant = 1. Setting the electric constant = 1 would simplify Maxwell's Equations. Therefore, why did Planck do this? | [
"If I'm understanding your question correctly you're asking why the coulomb constant, i.e. 1/(4 * pi* E0), is set equal to 1 instead of just setting E0 = 1 (here, E0 is the electric constant). I imagine people tend to opt for setting the coulomb constant to 1 because it makes the universal law of gravitation looks ... | [
"Sorry, I may be misunderstanding you again, but the universal law of gravitation was discovered by Newton long before Planck or Einstein were born. So, Coulomb's law and the universal law of gravitation were both well known when Planck came up with natural units."
] | [
"You're right, I thought the question was why Planck made the choice he did. ",
"As you mentioned, even though GR is the currently accepted theory for gravity, it still reduces to Newton's law of gravitation to an exceedingly good approximation for problems involving smaller masses and longer distances. So, it mi... |
[
"Electrolysis of a saline solution...OMG why is it turning brown?"
] | [
false
] | Here's the deal. Cup of water + 2 salt (NaCl) packets + 9V battery. Electrolysis right? Should get the breakdown of H2 gas as well as O2 gas. And that I apparently saw as bubbles would rise in a 2 to 1 ratio from each of the battery terminals. BUT WAIT!...after a minute or so of intense bubbling, there started to be a yellowish...then greenish...then brownish tint to the water. Clearly more reactions were at play here. What could account for the color change? NaOH? HCl? CuCl2 (copper from the battery?) OCl2? Help me chemistry mavens....you're my only hope! | [
"Well, for starters is it brown and cloudy or brown but still seethrough? If its cloudy that means its not water soluble, see through means it is. Knowing that is a pretty good starting point.",
"If its cloudy I'd recommend grabbing some on a paper towel or something and drying it out, then seeing if its magnet... | [
"What are your electrodes made out of? Copper would produce Green or Blue compounds in solution. Iron chloride is usually yellow or brown."
] | [
"Well, it's pretty low tech. All I've done is drop your standard duracell 9 volt battery into a cup of water. There's a bit of precipitate that has settled to the bottom of the cup, but the overall color of the water is brown."
] |
[
"If I had an extremely strong container, filled it with completely with water, and chilled it to 20 Degrees (F), would the water be able to freeze?"
] | [
false
] | If there is no room for the water to expand and ice to form, will it simply not form? I'm assuming the pressure on the outside of the container would be enormous. | [
"Yes! This has actually been done before. The water molecules will align themselves in a different manner on a molecular level, resulting in different crystallographic phases (i.e. hexagonal, orthorhombic...). You can see the full phase diagram ",
"HERE",
". Disclaimer though, you'll need a ",
" of pressur... | [
"Ice can be packed in at least 15 different ways, depending on the temperature and pressure applied to it. The various packing methods are numbered with roman numerals. Ice we experience in our everyday lives is \"Ice I.\" ",
"To achieve all the other forms of ice, you need to tune the pressure and temperature... | [
"How/Because?"
] |
[
"How do stomach bacteria differ between vegetarians and those who eat meat?"
] | [
false
] | Are there any bacteria that are specific to meat? | [
"Current research seams to show yes!",
" The linked study is from ",
" (so paywalled, unfortunately, though there's good info in the abstract), and showed that even very short term changes to diet can change the kinds of gut bacteria (people's microbiome) can change quite a bit. ",
"Not sure if it's that the ... | [
"Actually what you might not realize is that the digestive tract is actually part of the environment, like a tunnel running through you. Not quite internal."
] | [
"Yes, and I think a lot of caries are caused by bacteria from grain. Which helps to explain why the farther back in time you go in anthropological records the dentition becomes more intact.",
"When we switched away from meat toward grain as a staple we changed the bacteria in our mouths to accomidate strains that... |
[
"Why does a water droplet on dry ice freeze into a teardrop shape?"
] | [
false
] | While dripping water onto a piece of dry ice, I noticed that the pattern it froze in wasn't spherical- more of a teardrop shape. The effect seemed to grow as I repeated the process. I think it might be because the "bowl" in the dry ice grew each time I froze some water in it. Basically, small bowl= mostly spherical ice, big bowl= teardrop. I have no idea why this happens. Could someone explain it? | [
"I second the shrinking radius of the hemispherical drop of water at the top. The scale is small enough that intermolecular force starts to matter. On normal ice, the water molecules' self-attraction would prevent this sort of shape, but a little droplet on some non-polar dry ice would probably be able to sit at th... | [
"I second the shrinking radius of the hemispherical drop of water at the top. The scale is small enough that intermolecular force starts to matter. On normal ice, the water molecules' self-attraction would prevent this sort of shape, but a little droplet on some non-polar dry ice would probably be able to sit at th... | [
"The very first part of the water droplet to freeze will be a ring, on the bottom of the drop where it's exposed to both cold air and the dry ice. So now you have a ring of ice holding a water droplet in place.",
"Well, it will start freezing inward from there. But as water freezes, it expands; so you'll have a s... |
[
"Is there an effect the moon has on the atmosphere similar to the effect it has on the ocean by creating the tides?"
] | [
false
] | I imagine the effect of the moon may just be to create a bulge in the atmosphere close to the moon, but im not sure.... Does anyone know what the effect is and if it changes anything significantly, if so how? | [
"There is."
] | [
"Interestingly the atmospheric tides caused by the moon are far smaller than that created by the sun",
"And for those that are interested, there are also ",
"Earth tides",
" (did I capitalise correctly?) as well."
] | [
"According to ",
"google",
", 1 lunar cycle = 29.53059 days, and according to ",
"Wikipedia",
", the average menstrual cycle is 28 days long and anything between 21 and 35 days is normal. This means that it is highly likely that many women have menstrual cycles that follow the tides"
] |
[
"What makes Toxic Waste, War Heads, and other sour candies so sour?"
] | [
false
] | I love sour candy. I buy it all the time, it makes my eyes water, and I love it. Something that I've noticed is that a lot of it seems to be dusted in a fine white powder, which is the sour bit. Why is it so sour -- what is my tongue experiencing, and why does it make my eyes water? | [
"Neuroscience researcher here. What makes these candies so ridiculously sour is malic acid, which is more sour than the citric acid found in normal tart candies. There's one major cell in your mouth that lets you perceive sour and malic acid drives these cells batshit crazy. ",
"Warheads and Toxic Waste candies a... | [
"Sour is one of the five primary tastes (think like primary colors on a color wheel). Sour is the taste of acid. The more acidic the food, the more sour it will taste. Lemons, vinegar, spoiled milk, vomit, all of these contain significant quantities of acid.",
"Sour candies like Warheads are dusted with a powd... | [
"excitotoxicity",
"Wait... that last bit was a joke, right? Or do some candies/foods actually have a strong enough effect to cause excitotoxicity?"
] |
[
"Are there stars that are dull enough to be seen as flaming balls instead of just intense light with the naked eye?"
] | [
false
] | Do we know of any right now? How big or small could they be? | [
"I think that part of the difference between \"flaming balls\" and \"intense light\" is the variation. There are certainly dull stars, and there are stars which are the various colors found in fire, but any star you can see is going to appear as a solid dot - whether that dot is solid fire-orange, ember-red, or bl... | [
"I think he means, that of we were in space and looked at the star from a relatively close distance, would we be able to look at it and just see a ball of fire rather than be blinded by the light. I'm guessing the question is are there stars at such a low magnitude of brightness that we can just simply stare at the... | [
"This",
" is the dimmest true star. It is about 40 times smaller, 8,000 times dimmer and slightly less than half the effective temperature of our sun.",
"It should be about ",
"this color",
" based on the temperature. Iron would melt but tungsten lightbulb filaments and the sapphire lens in your smartphone ... |
[
"“In 1796, Edward Jenner, considered the founder of vaccinology in the West, successfully inoculated an eight-year-old boy against smallpox using vaccinia virus—from cowpox.” How?"
] | [
false
] | When first making a vaccine, how do scientists extract (harvest?) a virus and make it administrable to humans? After a vaccine is successfully made, can it just be made synthetically from then on? | [
"For the original cowpox inoculation it was literally just direct contact between the cow lesion and the boy. There was no vaccine per se just the concept of vaccination. Older vaccines used compromised virus by heat or chemical means - sometimes viable sometimes not. In the case of smallpox It worked because cowpo... | [
"In simple terms, they took cowpox which was largely non-lethal to people and deliberately exposed people and children to it.",
"The clue lay in the fact that during bouts of smallpox, milkmaids usually survived with fewer and less serious symptoms. When it was observed they caught cowpox from handling cattle, th... | [
"Pus from a cowpox lesion would be picked up on an implement like a small two tined fork with sharp points. Capillary action held a drop of pus which would wick into a scratch dug into the skin with the sharp points of the implement."
] |
[
"Properties of light scenario"
] | [
false
] | If one were able to create a box so that nothing could travel in or out (excluding neutrinos), and then install an LED inside this box, maintaining its seal, then turn it on, what would happen if the box is opened after the LED dies? Would a bright flash of light emerge? Would the box be empty, due to its constituent material absorbing the photons from the LED? Or would something else occur? Please excuse my ignorance, I am still in high school. Perhaps my understanding of the properties of light needs to be expanded. Edit: spelling | [
"A question almost EXACTLY like this played a big role in the development of quantum mechanics"
] | [
"If you're allowing the box to absorb the light, then the box heats up and \"heat\" leaves the box breaking your initial premise. Therefore what we're imagining is a box that is perfectly reflective in which light is continuously being added. I'm inclined to say that in such a thought-experiment, yes the box would ... | [
"If you're allowing the box to absorb the light, then the box heats up and \"heat\" leaves the box breaking your initial premise.",
"Not strictly true. You could have a box that absorbs the light, but is perfectly insulated to heat (as long as we're talking in hypotheticals). That still follows his premise."
] |
[
"Why do Human babies cry out loud? And why do they do it so much? Compared to other mammals"
] | [
false
] | null | [
"Using your google search, the only first page answer that actually answers the question asked is an un-sourced Yahoo Answers question. Other sites there include asking \"do other animals cry?\" \"when other animals scream, is it really out of fear?\" etc. "
] | [
"Using your google search, the only first page answer that actually answers the question asked is an un-sourced Yahoo Answers question. Other sites there include asking \"do other animals cry?\" \"when other animals scream, is it really out of fear?\" etc. "
] | [
"source?"
] |
[
"What's the largest diameter straw you could drink through?"
] | [
false
] | null | [
"Wait a minute, that's not true. The wider the straw, the more water it will contain at a given height. So for a normal straw, you have to apply a force equal to (density of water)*(pi*r",
" )*(height of straw)*(gravity) in order to get the water to the top of the straw; you need slightly more to actually have a ... | [
"EDIT: Allright, while everything above was technically correct, I forgot to consider that the pressure is ultimately delivered by your lungs/mouth, and that doesn't change surface area with the volume of the straw."
] | [
"Well, I just found a soda can, cut the top and bottom out and put it in a bucket of gatorade. Results: I pulled it through. Pretty sure the mouth diameter is the limiting factor here. I also coughed a lot and probably stained my white shirt."
] |
[
"I'm pretty interested in astronomy of late. What are some great books to start off with about learning and identifying constellations?"
] | [
false
] | . | [
"Get your real-time geo-specific sky maps and more at \"heavens-above.org\"",
" ",
"First link in the content lets you pick your location on earth from a google map. ",
"I believe there's a way to set up a cookie so that it remembers you..or sign in or something. Read. ",
"Anyway, once your coordinates ... | [
"I have the Audobon field guide to the night sky, it's a very accessible introduction to amateur astronomy. It doesn't go much into the astrophysics side of things, but is a great guide to constellations, planets, nebula, meteor showers, and the like.",
"I'd also recommend getting a red flashlight for reading th... | [
"Not sure what someone who really knows about this would say, but I have ",
"this",
" guide book and it worked well for me."
] |
[
"What caused the jump in atmospheric oxygen levels in the Ediacaran Period (635 Million years ago)?"
] | [
false
] | The Great Oxidation Event (2.4 -2 billion years ago) gets a lot of attention and it seems like the leading hypothesis for what caused it was the proliferation of early photosynthetic life. However, (as far as I can tell) the levels of atmospheric oxygen were still relatively low until after the Cryogenian glaciations. So, in short, what caused this later rise in atmospheric oxygen ? | [
"The Great Oxidation Event (2.4 -2 billion years ago) gets a lot of attention and it seems like the leading hypothesis for what caused it was the proliferation of early photosynthetic life. However, (as far as I can tell) the levels of atmospheric oxygen were still relatively low until after the Cryogenian glaciat... | [
"Thank you so much, it was bugging me. It's crazy to think that there was a time within the last billion years that you wouldn't be able to light a fire due to low oxygen, and that the evolution of animals might have changed that so quick."
] | [
"r/paleontology",
" may be the best place to ask this. We have such a limited understanding of the Ediacaran as a whole, only recently proving that some creatures were in fact animals.",
"The thing is, very simple animals like sponges and jellyfish could have arose long before the ediacaran. There is a rare pre... |
[
"Why does water drain around the circumference of a vertical pipe?"
] | [
false
] | null | [
"Is this just surface tension? Or something to do with the Coriolis effect?",
"It's neither of those, it's just conservation of angular momentum. When the fluid is poured into the sink, it will generally have nonzero angular momentum about the central point. What are the chances is has ",
" zero?",
"So as the... | [
"So it keeps that angular momentum as it travels down what's called the fixture outlet pipe, straight down from a sink or toilet drain, this makes perfect sense. Then it travels through a P-trap, changing the direction of flow by 270 degrees, before travelling in a mostly horizontal pipe (usually 2% of fall) for up... | [
"The flow has some vorticity when it goes down the drain, so in general the flow will remain rotational."
] |
[
"From what I have learnt so far, refrigerators use chlorofluorocarbons for cooling. Do these chlorofluorocarbons run out after some time? If yes how are they replenished?"
] | [
false
] | null | [
"They are not “consumed” per se, although like any system where you trap a gas in a container there is potential for leaking.",
"AFAIK modern refrigerators are sealed systems. That means less likelihood of loosing coolant, but much greater difficulty in adding more back in.",
"Car and home (central) AC systems ... | [
"A refrigerator takes advantage of the thermodynamic properties of these compounds and put them through a physical change. It is a 4-step vapor-compression cycle. Liquid refrigerant is passed through the refrigerator which removes heat and boilers the refrigerant, this is the \"cold sink\" in the process. A compres... | [
"As person who assisted with repairing of friges, mostly industrial but few domestic as well. There are valves too."
] |
[
"Just how far can signals from Earth go?"
] | [
false
] | Particularly how far until nothing can be recognized anymore due to interference. | [
"There is no fundamental limit. You just need larger receivers and more time for larger distances.",
"The Arecibo telescope could reasonably send text messages and even some images to equivalent telescopes on planets orbiting nearby stars, with decreasing transmission rate for larger distances. Make sender and re... | [
"Space is almost entirely empty space. Take a look at ",
"this",
" for some perspective. "
] | [
"Voyager 1 was launched in 1977, and in 2012 became the first spacecraft to cross the heliopause and enter the interstellar medium. It's now more than 11.7 billion miles (18.8 billion kilometers) from Earth, and ",
"we're still in communication with it.",
". So we probably don't know yet what the limit is. The ... |
[
"Do snowflakes deaden sound?"
] | [
false
] | It always seems quieter outside when it snows (as long as there's no wind) .. is my logic correct that all those little particles could deflect (reflect?) sound? | [
"Snow also, if it is on the ground and the objects around you, acts like ",
"acoustic foam",
", thus deadening the noise."
] | [
"There's probably more to this, but sound doesn't travel as fast or far through cold air than through warm air.",
"I would imagine that, and the dampening factor of the snow acts kind of like yelling at a blanket."
] | [
"I hadn't even considered air temp! That makes a lot of sense."
] |
[
"If I were to point my telescope at a nebula, would it show up in colour?"
] | [
false
] | Do the images from HST have false colouring? | [
"Usually false-color. Images of nebulae typically include narrow-band filters which pick up only a specific emission line, such as H alpha or OIII. These filters are usually colored corresponding to where they are on the EM spectrum, so H alpha is usually colored pinkish or red because it's at 656 nm.",
"This sit... | [
"Depends what telescope and what nebula. With my 8\" SCT, I can can just about make out the faint colours of the Orion Nebula. However, orion is really the only nebula bright and large enough to appear colourful with an amateur scope."
] | [
"Perhaps. I have a 14\" telescope and I can't see any colour in the Orion Nebula (naked eye). Some people looking through my scope can so perhaps it depends on the person to an extent, and of course, the nebula itself."
] |
[
"Is there any geographic evidence of the asteroid impact that wiped out the dinosaurs?"
] | [
false
] | null | [
"Yes.",
"\n",
"The Chicxulub crater",
" is off the Yucatán peninsular.",
"\nThe land around it is lower than the land surrounding it, just the entire thing is so large people didn't notice it at first.",
"\nWith satellites we've noticed a gravitational anomaly on the whole area.",
"\nWe've also noticed ... | [
"Yes there is. In addition to the huge crater in Mexico, there is a planet-wide layer of Iridium. This is called the K-T boundary. It's called this because it's located between the Cretaceous and Tertiary layers of strata. (K and not C because it was a German scientist who discovered it, they spell Cretaceous with ... | [
"That actually has to do with preservation conditions, not so much with the location of the impact which anyway caused a ",
" extinction event. ",
"The Mongolian Gobi Desert is the largest dinosaur fossil reservoir in the world",
" but it's very far from Yucatán."
] |
[
"Why is it that romaine lettuce healthier than iceberg lettuce?"
] | [
false
] | null | [
"Iceberg lettuce has been bred for crispness and size, while romaine has been bred for flavor.",
"In retrospect, breeding for crispness leads to a head of lettuce that is mostly cellulose and water. Romaine lettuce by contrast retains the vitamins and antioxidants common to green vegetables."
] | [
"Looking at the raw data, it seems that romaine by weight is much higher in vitamin content. Now, whether vitamin content is sufficient to conclude that it is healthier or not I'll leave to the reader.",
"Sources: ",
"Romaine",
" v ",
"Iceberg"
] | [
"This may help if you want to take a look: ",
"http://www.wolframalpha.com/input/?i=+compare+romaine+to+iceberg+lettuce"
] |
[
"When you take a drug (say caffeine) for a while and the receptors for that drug get 'down-regulated' what actually physically happens?"
] | [
false
] | [deleted] | [
"/u/Lee_the_scientist",
" gave a good answer. I'll elaborate on some of the points he made and add a few of my own.",
"The mechanism whereby tolerance is established varies depending on the particular drug. Long term administration of an activating ligand often results in downregulation of the receptor by enhan... | [
"When a Ligand binds to a receptor many things can happen, first a confirmation change occurs which leads to receptor signaling. That receptor can then be destroyed via endocytosis of the membrane where the receptor is. That endosome can fuse with a lysosome and be destroyed. That's one way to down regulate a recep... | [
"How reversible it is? How long until tolerance drops?"
] |
[
"Why do stars appear to flicker but planets don't?"
] | [
false
] | [deleted] | [
"It has nothing to do with the distance the light travels, because all the twinkling we see happens in the last 50 km the light has to travel. The Earth's atmosphere is solely responsible for twinkling (and is a major advantage offered by telescopes in low Earth orbit, such as Hubble).",
"The reason stars twinkle... | [
"Something else. ",
"The light of every object passes through the earth's atmosphere. Now all objects appear as tiny disks to an observer on the ground. The thing is, stars are so far away, that their disks appear extremely tiny, literally pointlike. When you have an atmospheric turbulence, it smears and shifts t... | [
"Actually they flicker, but because of their size you don't notice it, I do Astrophotography as a hobby, even the moon and the sun flicker, but you will see it if you use a telescope, that is why planetary astrophotographers don't use long exposures, rather they record video of the solar system object, lets say Jup... |
[
"Why is it that when we look at bright objects we see extra artifacts surrounding it, such as vertical lines of light?"
] | [
false
] | This was a little hard to explain, so I've attached an image It's particularly sunny today, and I noticed that most bright objects had these distinct, vertical lines. I'm a physicist by trade, but the best I can come up with is a lensing effect from our eyes (which makes sense). I'd love some more insight on why this occurs with humans and if there is any biological mechanism behind it as well. | [
"The bright lines in that particular picture look like ",
"CCD smear",
", an artifact caused by a certain type of image sensor.",
"For the vertical lines that you see with your own eyes, do they get more pronounced (brighter, longer, or larger) when you squint? If so, I think it may be ",
"the phenomenon de... | [
"I agree with your first point; I chose that image because it most closely imitated the effect I was trying to describe, I understand that the causes of the two effects are different. ",
"As for the vertical lines I'm seeing, I was not squinting. The sources were just unusually bright (noon time, no clouds, refl... | [
"I asked my optometrist this same question, as well as researching it on my own. What I have come up with matches everything the professional said, of course. The optometrist called them \"spokes,\" and I believe spokes of light is the most common search term on the internet concerning them. If there's enough to fo... |
[
"Are facial expressions instinctive or something that must be learned?"
] | [
false
] | For example, if there was a feral child who had NO human contact (that he/she can remember) in their entire life, would they know that smiling meant someone was happy? I imagine things like a wolf showing it's teeth would be instinctive, and even if you had never seen a wolf before you would know it is pissed. | [
"Also: blind children all over the world (blind from birth) make similar facial expressions."
] | [
"They are instinctive. Though there are subtle cultural variations and specializations, we seem to have a small set of universally-recognized and utilized facial expressions. Infants make exaggerated facial expressions before they could reasonably be expected to have learned them.",
"In addition, I'll just poin... | [
"You should check out research by ",
"Dr. Paul Ekman",
", a renowned psychologist who primarily does research on emotions and their facial expressions. He's done meticulous hours of coding to categories the countless faces' expressions from cultures all around the world, including indigenous ones. He also has t... |
[
"Question about Electricity and Wind Farms (Help With My Son's Project)"
] | [
false
] | My son and I recently visted the with his Cub Scout Den, and his leader is asking each of the boys to make a poster with facts about the farm. We found plenty of information on the interwebs, but I want him to understand what he's putting on the poster. The Wind Farm is capable of producing 24 MW. Is this per hour? Per Year? What is the best way to explain (to 8 year olds) how much power this is? I did google this but couldn't find what I as looking for. Thank you in advance. EDIT: Thank you to everyone for the help! You've given me the info I was looking for!! | [
"MW (megawatts), is a measure of energy produced per second. Megawatts is a measure of power, so the maximum power is just 24 MW. So basically, the mill is capable of spitting out a maximum of 24 megajoules of energy per second"
] | [
"The Wind Farm is capable of producing 24 MW. Is this per hour? Per Year?",
"No, it's just 24MW. A watt is defined as one joule per second.",
"According to ",
"Wolfram Apha",
", 24 megawatts is enough to power 4000 - 8000 US households."
] | [
"Another way to picture 24MW is with kettles. Kettle is roughly 1KW I think, so 24000 kettles. "
] |
[
"Are artists really prone to mental illness and why?"
] | [
false
] | [deleted] | [
"About five years ago I took a master's level course called \"Creativity and Intelligence.\" I have also often wondered why it seems that so many creative individuals are often also mentally ill. The answer the course and the professor provided was along the line of, \"We're not really certain of the 'why' but th... | [
"Addiction is a mental illness. Also, drug use is not the same thing as addiction."
] | [
"I don't have an answer for you, but I'd like to point out that the causal link you seem to be looking for could be reversed. An equally valid research question could be: Why is it that so many people who are prone to mental illness become amazing artists?",
"Ninjaedit: specificity."
] |
[
"Why does too much water kill my plants?"
] | [
false
] | [deleted] | [
"Roots need oxygen to survive, so too much water will literally drown a plant. In addition too much water can cause the growth of mold which can kill the plant."
] | [
"They have adaptations that allow them to live underwater."
] | [
"They have adaptations that allow them to live underwater."
] |
[
"Do bone conduction earphones protect hearing?"
] | [
false
] | [deleted] | [
"There's no reason to believe that they would. Hearing loss is usually caused by damage to the inner ear, which is still getting as much sound exposure with bone conduction as it would through the normal path of sound."
] | [
"I would guess bone conduction earphones were provided due to being excellent at maintaining sound clarity in very noisy environments (as you said, it was windy). Most likely has nothing to do with protecting hearing."
] | [
"Sort of a piggyback question: Could I have bone conduction earphones that are inside my ears, with no visible wires between/outside? That would be cool to \"play\" music from within my ears. Would I need a wire inside of me? Maybe a quick-release 3.5mm in my abdomen..."
] |
[
"Why hydrogen is placed on number one in modern periodic table?"
] | [
false
] | null | [
"Hi Bhootnathmainhoon thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of t... | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"To check for previous similar posts, please use the subreddit search on the right, or Google site:reddit.com",
"/r/askscience",
" ",
"Also consider looking at ",
"our FAQ",
... | [
"Because it has one proton",
"Helium, the second element, has two protons. The third element has three protons, and so on and so fourth. "
] |
[
"Why are oxidation reactions exothermic?"
] | [
false
] | A biochemistry professor of mine once posed this question: Why are oxidation reactions exothermic? According to my professor, it took a quantum chemist to answer it. If I remember right, it had something to do with the resulting electronic structure of the oxidation products, but I can't remember the details. | [
"You have a chemical that has electrons, but doesn't hold them that tightly (the reducing agent = fuel) and something that wants more electrons than it already has (oxidizing agent = oxidizer). The reducing agent gives up some electrons that were easy to give up and the oxidizer gains some electrons it wanted. Th... | [
"The answer is in molecular orbital theory. ",
"The slightly longer version of, \"the oxidizing agent wants electrons,\" is that the open energy levels of the oxidizer are lower-lying than the highest occupied orbitals in the reducing agent. The electrons get to fall to lower energy levels in the products from ... | [
"A very unsatisfying answer coming up, but I hope it might be a starting point. It depends what you mean by \"oxidation\" and how deep you want to go.",
"At the shallowest level, exothermic reactions are ones where the products have lower enthalpy than the starting points. So I could give you the answer: \"Becaus... |
[
"If a submarine loses it ability to function underwater, is it possible to “tow” it back to the surface?"
] | [
false
] | null | [
"Yes, there is emergency air to blow the water out of the ballast tanks. We used 4500psi air to blow the tanks.",
"My previous answer was in response to the question \"What if the mechanism for filling and depleting the ballast tanks fails?\"."
] | [
"Submarines dive by filling ballast tanks with water. When the sub dives, air from the tanks is compressed into storage tanks, and replaced with seawater. In an emergency, the compressed air can be released back into the ballast tanks, blowing the seawater out and restoring positive buoyancy. Google \"submarine eme... | [
"They would need a DSRV to rescue the crew in that case. There is no method for raising a submarine by hoisting it or \"towing\" it to the surface - they are simply too heavy. I served on a submarine - USS DRUM (SSN 677) - back in the day."
] |
[
"Is it possible to see the top of lightning?"
] | [
false
] | It has to start from somewhere, so does it have a top? | [
"There are such things as ",
"sprites",
"), which shoot off away from the top of the cloud when lightning strikes below it. Probably not precisely what you're looking for but very interesting nonetheless..."
] | [
"When it comes to atmospheric electrical phenomena, lightning is only the beginning of the awesome.",
"http://en.wikipedia.org/wiki/File:Upperatmoslight1.jpg",
"Closest I've seen to a top:",
"http://en.wikipedia.org/wiki/File:Sprite_seen_from_space.jpg"
] | [
"Well anything about lightning is cool, thanks. \nI'm just wondering if seeing the top of lightning is possible. It's always surrounded by clouds, and clouds aren't exactly solid (right?) so shouldn't the lightning go through it? Idk..."
] |
[
"What exactly is missing for the covid-19 vaccines to be full approved, and not only emergency approved?"
] | [
false
] | I trust the results that show that the vaccinea are safe and effective. I was talking to someone who is not an anti Vax, but didn't want to take any covid vaccine because he said it was rushed. I explained him that it did follow a thorough blind test, and did not skip any important step. And I also explained that it was possible to make this fast because it was a priority to everyone and because we had many subjects who allowed the trials to run faster, which usually doesn't happen normally. But then he questioned me about why were the vaccines not fully approved, by the FDA for example. I don't know the reason and I could not find an answer online. Can someone explain me what exactly is missing or was skipped to get a full approval? | [
"TL;DR - FDA approval is designed on purpose to be a ",
" to make sure a product is ",
" It's a process made hard on purpose. ",
"Meanwhile, an emergency use authorization slims down the red tape while still requiring a proven safety and efficacy record. ",
" If normal FDA approval is like a 300-guest wedd... | [
"wasn't it already made available for the EUA?",
"Yup. There's a duplication. The same information has to be submitted for both. ",
"The difference is like a courthouse wedding vs. a 300-guest wedding. They both ",
" require the same things (a bride, a groom, not related, not coerced, wanting to be married, w... | [
"Thank you so much for the great answer.\nI think I was able to follow everything, but I still have a question.\nI understand that the EUA requires everything to say that a vaccine is safe, produced well, and effective.\nI understand that the BLA is a big amount of work and very formal procedure. But it seems to me... |
[
"Why are antibodies ineffective against certain illnesses, or is that even the case?"
] | [
false
] | With infections like HIV and Lyme antibodies seem to exist but don't necessary completely defeat the illness. I'm sure there are others as well. If antibodies are ineffective, why is that? Through medical research could we make 'steroids' for antibodies to make them stronger/faster/whatever to perhaps make them effective? | [
"Some rare people develop antibodies that control HIV. One of the problem with antibodies is that pathogens can mutate themselves so that where the antibody would bind has changed, making the antibody ineffective. This is the major problem in HIV, because HIV has an extremely high mutation rate. Through natural ... | [
"As other commenters have noted, there are many ways that pathogens can avoid detection by antibodies or resist or suppress the body's antibody-mediated reactions. I could go on for chapters describing all the known ways these evasions happen but I'll let what others have said suffice.",
"Since the methods of ev... | [
"Alot of diseases have methods to avoid antibodies. Antibodies float in the blood and if an infection is in a cell or surrounded by a coat that protects them from antibodies then they have no effect. There are currently no methods of improving antibodies function. With HIV the virus lives within cells for the m... |
[
"On what basis is it decided that which medicine will be in form of capsule or tablet?"
] | [
false
] | I have opened many capsules and found a variety of type of medicines, like granules or powder but can't they be pressed into tablet form? Since most of the tablets are hard pressed powders (i might be wrong on this) | [
"Tablets are generally for medicine who you want to dissolve and absorb without regulating the speed of which they are absorbed or where they get absorbed ",
"Capsules, depending on the type of medicine, gives you control over that. Some capsules can tolerate stomach acid to protect the medicine and then dissolve... | [
"Many different things can determine the composition of how a drug is delivered. Even what looks to be simple powdered/compressed drug can be mostly powdered cellulose (plant fibers) as a binding agent and to increase volume. Gels may help with rapid absorption. There might be a safety coating for your stomach. Som... | [
"Definitely, although probably very small since there are many very cheap capsule. Advanced capsule that can time release probably is more expensive. ",
"In general, the difference between brand name and generic of any specific medicine lie in the quality of the carrier vehicle and how well it works"
] |
[
"Why do antibodies in Rhematoid Arthritis patients attack only joints?"
] | [
false
] | null | [
"They don’t.",
"RA can attack multiple organs and has a very variable expression. It is known for causing heart and lung problems. Including pericarditis, vasculitis, interstitial lung disease, pleural effusions. Also hematologic manifestations and neuropathies. It can certainly have a lupus-like picture.",
... | [
"Thank you physician, for caring and being an open minded critical thinker. I write this with sincere meaning."
] | [
"The rheumatoid factor antibody does not attack joints. It actually attacks other antibodies (the Fc portion of IgG). These immune complexes (antibodies bound to each other) are found in people's joint synovium and joint fluid.",
"The joint damage in rheumatoid arthritis is actually caused by a complex interplay ... |
[
"How good are the ISS solar panels compared to currently available solar panels?"
] | [
false
] | Since there's been a lot of advancement in panel tech (I hope anyway) was curious to see if there was a big difference. I'm sure the ISS panels are state of the art when put in. Edit: I don't actually know what category this belongs in. Engineering sounds about right though. | [
"Their efficiency is quite a bit less than what's currently available.",
"ISS panels: 21 W/m",
" [",
"source",
"]",
"Commercially available, consumer panels: 143 W/m",
" [",
"source",
"]",
"Sounds considerably worse but the ISS panels and the commercial panels are prioritizing different things.",
... | [
"Awesome, Thanks! That is a pretty big difference."
] | [
"Energy density - there's plenty of space around the ISS",
"I wouldn't go that far. More area = more friction = ISS loses altitude faster and you need to raise the orbit. Not to mention constraints from the launch vehicle -> you need to fit the panels somewhere! Also there is a problem with large panels that part... |
[
"Has anyone ever been successfully cryogenically frozen/unfrozen?"
] | [
false
] | I know this might be silly as I've looked on the internet a bit but it just seems realistic and I Want to know how we've advanced on that if t all. And walt Disney? | [
"Well, all intentional cryogenic freezing must be done after the individual has died. Since we have no technology that can reverse death yet, no we haven't unfrozen someone and resuscitated them from ",
" cryogenic freezing.",
"However, \"unintentional cryogenic\" freezing happens in accidents in cold weather c... | [
"I can't find the story right now, but I recall reading about a successful freezing/unfreezing in Japan, where they used a rapidly oscillating magnetic field to prevent the cooling water from forming crystals (which is apparently the damaging part of the freezing process).",
"I realize this is not a scientific po... | [
"No. And it won't happen for some time. The thing is, when you freeze a body, microscopic ice crystals form that perforate cells. When you thaw the body, almost all the cells are dead and so then is the whole. Cryogenics companies do replace much of the bodily fluid with a sort of \"anti-freeze\" that is suppos... |
[
"How can a new species be classified with only a partial fossil? What if that particular creature was just deformed?"
] | [
false
] | [deleted] | [
"The key to identifying something as a new species relies on isolating some unique feature - something that is found in no other species known. That's the fundamental goal of studying morphology (or genetics) of different species. By contrast, classification relies on finding shared similarities between species, id... | [
"Modern paleontology uses morphological phylogenetics to determine the relationships of taxa. The gist is this: different groups have characters present on the skeleton (or in their soft tissue, but that rarely preserves) that are unique to that group. This is true for higher level taxonomic groups, like orders and... | [
"Oftentimes you can get down to the family or order just because bones look characteristic. On my qualifying exam, one professor pulled 2 random fossils out of his briefcase for me to identify, and it wasn't that bad.",
"My labmate is currently publishing a statistical algorithm that will identify unidentified an... |
[
"AskScience AMA Series: I’m Dr. Julia Shaw, a memory scientist and criminal psychologist. I study how we create complex false memories. AMA!"
] | [
false
] | ** ** Hi Reddit! I study how we can create incredibly detailed memories of things that never actually happened. In particular, I implant rich false memories of committing crime with police contact and other highly emotional autobiographical events. I thought I’d share my work with the community, since I’m an avid Redditor. The technique I use in my research is essentially a combination of what's called “mis-information" (telling people convincingly that something happened that didn’t) and an imagination exercise which makes a participant picture the event happening. The goal is to get my participants to confuse their imagination with their memory. I find, as do many other scientists who study memory, that it is often surprisingly easy to implant memories. All of my participants are healthy young adults, and in my last study 70% of them were classified as having formed these full false memories of crime by the end of the study. I am currently working on further research and analysis to see whether I can replicate this, since this success rate was incredibly high. Last year some of this research, which I did with Stephen Porter at UBC, went viral. It was so amazing to see such a great reaction from the press and public. There really seems to be a thirst for wanting to understand our faulty memories. You can see my favourite write up of the research . In “ ,” a NOVA documentary airing tonight on PBS at 9pm Eastern time, you can actually see some real footage from the videos that I made during the interviews, which you can see . I actually have a whole book coming out this summer on memory hacking. It’s the first popular science book of it’s kind, and I’m super excited about it! If you find my research interesting you’ll definitely like the book. The book will be released in 8 languages (English, German, Dutch, Portuguese, Italian, Taiwanese, Chinese, and Japanese) and will be called “The Memory Illusion”. You can get preliminary information about it . If you want to know more about me and my science, and get free access to all the research I have published to date, go . Read my Scientific American contributions (almost all of which focus on memory errors) . Follow me on Twitter: @drjuliashaw I will be back at 1 pm EST (10 am PST, 6 pm UTC) and I will answer the most creative comments first! Julia | [
"Is there a way to reverse this? Or to somehow find out which is the \"true\" memory?"
] | [
"Hello Dr. Shaw! Thanks for doing this AMA. My question is, are some people more susceptible to creating false memories than others? If so, what are some characteristics that contribute to this susceptibility? Thanks."
] | [
"Great questions! ",
"There are two questions you seem to be asking. ",
"Q1: The first is whether not we can tell the difference between a true memory and a false memory, and the answer is “probably not”. ",
"When we show videos of false memories and true memories to participants in research studies, they gen... |
[
"Why don't cars have frontal and rear magnetic fields to prevent collisions?"
] | [
false
] | Let me explain: If you could have two negative poled magnets at the back and front of every car, where the magnitude of the magnetic field increased the closer you approach the magnet, wouldn't this be an effective measure to help the deceleration of cars upon impact? This, in addition to the crumple zone, could increase the time for deceleration, and thus decrease the overall force, right? Concerning issues of parking in close spaces; the magnetic field could be electrically induced, and turned off when the car stops, meaning that it would not interfere with other cars when not in motion. (Perhaps, active when a set speed is achieved.) I am asking whether this could be a possibility, and if so, why is it not being marketed? Thanks. | [
"I just spent a funny two minutes imagining magnetic quadrupole cars driving around our streets. ",
"To get a force in the ballpark of being able to stop a car, you need very massive magnetic fields that require huge, heavy coils and tens of kW of electric power. A junkyard magnet has maybe a few Tesla and requir... | [
"Not to mention if you're going fast enough the magnetic field will do just as much damage to your car as a crash. A force is a force, it doesn't matter if it's the normal force of the car in front of you or magnet, its rapid deceleration of a portion of your car relative to the rest of it (and you for that matter)... | [
":) As with all things in engineering, it's a matter of the cost and benefit. If 50-60 years ago, somebody tried to compare the feasibility of trying to brake a car using quadrupole magnets vs. using a bank of computer processors that used radar/lidar ranging, advanced image processing/3D environment recompositio... |
[
"What occupation has the longest life expectancy? Shortest? (x-post from AskReddit)"
] | [
false
] | null | [
"For shortest, my best guess is ",
"underwater welders",
". They generally only live 10 to 15 years, but they make a ton of money in hazard pay.",
"Most studies put the longest life expectancy with nuns (if you count that as a profession). Their average life expectancy is ",
"86",
" years. Low stress, hea... | [
"Shortest? Occupy LA?"
] | [
"Alaskan fishermen, elephant zookeepers and professional horse jockeys all have reputations of not lasting very long. Don't know the average lifespan though. Since most American zoos switched to protected contact (= keeper never goes in with elephants any more) the keepers are doing a bit better, but a bull still g... |
[
"Why does the expansion of space only affect huge structures?"
] | [
false
] | Why aren't the sun and the earth pushed away from each other? Is gravity so strong that it easily cancels dark energy out on small scales? Is dark energy not distributed equally? | [
"Is gravity so strong that it easily cancels dark energy out on small scales?",
"I'd more think of it as \"Gravity between galaxies is so weak that it gets overwhelmed by the expansion.\""
] | [
"Why Brooklyn is Not Expanding"
] | [
"Some people have said that locally, gravity and other forces overwhelm the dark energy. This is partially true, but I think there's a more fundamental way to understand why the expansion of the universe is only apparent on cosmic scales, which would remain valid even if we ignored all other forces.",
"Imagine th... |
[
"What exactly is the prevailing theory about how life began on earth?"
] | [
false
] | [deleted] | [
"There's the ",
"RNA world",
" hypothesis, recently, there had been a demonstration ",
"in the lab",
" of RNA replicating itself. ",
"There's no way to really know what happened 4 billion years ago, as this stage of life didn't leave anything behind, but it seems that this hypothesis is a pretty good one.... | [
"To add to the nice explanation above on the 'RNA hypothesis' for origin of life, this recent (Oct, 2018) publication suggests a role for liquid crystals in formation of initial RNA strands that would be necessary for the transition of non living chemicals to form self-replicating structures.",
"American Chemical... | [
"I don't think there is a prevailing theory from what i am aware except several different hypothesis.",
"Many of the components of DNA exist freely in space, some have been identified in meteorites for example.",
"Its possible that lightning strikes on water could have caused some reaction/bonding but i'm not e... |
[
"If you could flip a coin in a vacuum with the exact same force and at the exact same angle each time, would it always land on the same side?"
] | [
false
] | null | [
"Yes. If all the variables are controlled, the outcome should be the same. ",
"Now, a perfect vacuum is experimentally impossible to achieve, but if we're talking about something as large as a penny, subatomic particles really won't make much of a difference on the penny."
] | [
"If the air was carefully contained (IE no gusts) its effect on the motion of the coin would be the roughly the same every flip, so it would land on the same side. It's mainly the difficulty in maintaining a precise force and angle that causes the randomness in everyday coinflips."
] | [
"Probability is a branch of mathematics. There's nothing debatable about that. It's the branch of mathematics that deals with the likelihood a random event will occur. ",
"True randomness does exist, but just at a quantum level. ",
"Have a read",
". ",
"When you get up to something as macroscopic as the phy... |
[
"Is it possible for a solar flare to knock out the electrical grid for a long period of time?"
] | [
false
] | How likely is this to happen? | [
"Yes, it is without a doubt possible.",
" When we speak about solar flares we are generally referring to the ",
"emission of radiation",
" from a magnetic reconnection event in the Sun's higher atmosphere. These flares are not always but are often linked with an ejection of matter from the Sun called a ",
"... | [
"So, given we find out that a Carrington type flare were to hit tomorrow, how would we prevent damage? Would turning off the power be sufficient, or would people have to go around physically disconnecting wires from the transformers?"
] | [
"How far ahead can we reasonably predict flare activity? If the Mother Of All CME's were brewing, would we know a week ahead of time?",
"Like I said we have at least a 1-3 day warning from the flare to the CME arrival at earth, the time is less for bigger events but is never less than about a day.",
"It just be... |
[
"Can gamma rays break apart small nuclei?"
] | [
false
] | If fully ionized (electron free) nuclei of elements like hydrogen or helium or oxygen are hit with an extremely high-energy gamma ray, what happens? Would it cause the oxygen to undergo fission? Would it even interact with the hydrogen? Assuming it does interact, what happens? | [
"High energy gamma rays can cause particles to be knocked out of nuclei. They can even cause fission."
] | [
"Fission generally refers to a nucleus splitting apart into two heavy ions. There's a whole spectrum starting at single nucleon emission, light ion emission, \"cluster\" emission, and spontaneous fission. Where exactly the lines are drawn is somewhat arbitrary, but there are some significant physical differences be... | [
"Why is particle emission (protons, neutrons, alpha) not considered a type of fission?"
] |
[
"If our telescopes were powerful enough could we see the starting point of the big bang?"
] | [
false
] | It seems like the light from the big bang would have passed us by long ago. | [
"If we are looking at electromagnetic radiation, we can only see back to about 400,000 years after the big bang when the electrons in the universe became bound to the protons and it became transparent. This is the cosmic microwave background (CMB). We can look for signatures in the CMB from before that, such as the... | [
"There is no center of the universe. The illustrations of the big bang shown in almost all TV shows, where it looks like a spherical explosion away from a point, are completely wrong.",
"The universe appears to be infinite, and has always been infinite for all times after the big bang. This means light from the... | [
"This blows my mind. It's like an ant trying to figure out if the earth is round."
] |
[
"What specifically causes 'pins & needles', and why is it sometimes quite painless and tingly, but at other times very painful?"
] | [
false
] | null | [
"Parasthesia (the sensation of pins & needles) is most commonly caused by ischemia, pressure, stretch, or damage to peripheral nerves. When damaged or even under duress these nerves can send aberrant signals to the brain which may be interpreted as pain. Prolonged injury can cause numbness as well. Sensory neurons ... | [
"It might not be damage that's occurring, it could just be temporary stretch or ischemia. Once the insult to the nerve is relieved the normal function returns. Prolonged insult to the nerve can cause longer lasting effects. 'Saturday night palsy' is a term for when someone passes out awkwardly and compresses part o... | [
"I assumed it was just lack of circulation, but you're saying I am doing damage to my nerves when I say, sit awkwardly and don't necessarily notice that I'm creating conditions for parasthesia? That damage must resolve quickly, if the feeling only lasts for some minutes?"
] |
[
"Why does your vision improve when you squint?"
] | [
false
] | null | [
"Not sure there is much to add beyond the canonical/Googleable answer:",
"Without really understanding why, many with vision problems find themselves squinting in order to focus. [...] By squinting, vision is able to improve slightly. But how does it work?",
"First, squinting decreases the amount of light that... | [
"This question has been asked many times before:",
"https://www.reddit.com/r/askscience/comments/11mmw3/why_is_it_that_people_sometimes_see_better_when/",
"\n",
"https://www.reddit.com/r/askscience/comments/vhas1/how_come_we_often_squint_our_eyes_in_order_to_see/",
"\n",
"https://www.reddit.com/r/askscien... | [
"Another thing to note is that often images will become clearer when viewed through a pinhole thanks to a similar effect. You can try this easily by making a very small hole between the ends of your two index fingers and a thumb and looking through it. This is a trick I use when I forget to take my glasses places."... |
[
"Are there \"planes\" in the ocean? Like a desert, but in the ocean, so flat expanses of ocean floor where little to no life dares to dwell or live?"
] | [
false
] | Better explanation? Desert, but underwater. | [
"Most of the deep ocean floor is pretty barren of life. Never gets sunlight, so it subsists entirely on marine 'snow', rotting stuff falling from above. Areas where there's little surface life will only exacerbate that. And there's certainly vast abyssal plains where the ocean floor is pretty flat. I'm not aware ... | [
"I understand your question, but dont know too much about specific ecosystems in the ocean.",
"However, I do know a decent amount about deserts, having grown up in one (and listening/learning about my local environment).",
"A desert is classified by a lack of rain, not by a lack of life. There are a wealth of s... | [
"after watching the bbcs oceans documentary there's apparently plains near the corals of Australia, the clown fish from nemo live in coral thats poisonous to all but them there, and while there,s not as much life a in other parts there,s still stuff living there. It looked like there's basically life everywhere in ... |
[
"What determines how electrons return to the ground state after they are excited?"
] | [
false
] | [deleted] | [
"If the atom starts in a given excited state, it has some probability to transition to each lower energy level. It's probabilistic, but some are going to be much more likely than others.",
"What determines the probabilities for transitions to each final state is a few things.",
"Fermi's golden rule",
" states... | [
"Is angular momentum at all related to the type of orbital?",
"Yes, there's the orbital angular momentum quantum number (ℓ) as well as the spin quantum number (1/2) for each electron.",
"These are summed over all electrons to give the total angular momentum (J) of the atom, in a given state.",
"Transitions be... | [
"Wow thanks for the great answer! Is angular momentum at all related to the type of orbital? As in, does changing between different orbitals relate to changing angular momentum like you were talking about? If not, what exactly does the angular momentum of an electron mean? Is that the same as electron spin? "
] |
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