title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Does the Universe truncate?"
] | [
false
] | Einstein's Field Equation for general relativity involves pi. Pi is a transcendental number. It would be impossible for any computer to calculate the exact result of this equation, since pi is infinitely long. Yet the Universe manages to do it instantaneously, all the time. Does the Universe truncate its answers? How c... | [
"The universe has no problem handling irrational numbers. Just because we cannot replicate them in our digital machines, does not mean they do not exist. "
] | [
"You're assuming the universe is like a machine."
] | [
"Equations and formulae describe the universe, not the other way around. It isn't \"impossible to calculate the exact result (of a number with pi in it)\" in reality because you can just leave pi in the answer. 2 pi is ",
" the number of radii that fit in the circumference of a circle in euclidean space. On compu... |
[
"Why is space black?"
] | [
false
] | This might be the most stupid question ever, but I thought of this yesterday and, well, what the hell! What am I seeing when I see the black between celestial bodies? Why is space so black? | [
"It's not a dumb question at all! It's a rather famous paradox -- if the universe is infinite, why don't you see a star in every possible direction? This is known as Olbers' paradox:",
"http://en.wikipedia.org/wiki/Olbers%27_paradox"
] | [
"Here's an explanation, and resolution, of Olbers' paradox:",
"http://www.universeadventure.org/big_bang/popups/conseq-dtrh-olbers.htm",
"Explaining exactly why the sky is black."
] | [
"First, space is huge. The distance between light sources (stars, etc) is enormous.",
"Second, space is VERY dusty - you think ",
" have dust bunnies, the universe has you beat hands down. Dust obscures a lot of the light. This is the reason that looking up at our milky way galaxy does not look as impressive ... |
[
"Biology - How do onions grow?"
] | [
false
] | Do onions add layers as they grow or do they start with all of their layers and they get thicker as they grow? | [
"Onions are just one variety of ",
"bulb",
", which means that the fleshy part that we eat is just a section of modified leaves attached directly to the diminished stem called the 'disk' or ",
"basal plate",
". ",
"Those fleshy scales grow sequentially as the bulb develops. The fleshy scales are produced ... | [
"In our common onion cultivars the fleshy scales grow from the inside, pushing older layers outward. Much like the bark on a tree forming from the outer cambria, as the outer-most layer of cells expands the cellular integrity becomes compromised and it undergoes a conformational change. In the case of these onions,... | [
"So, all the leaves keep growing and the outer 1 or 2 die, then the outer layers keep dying?"
] |
[
"Can someone describe the phenomenon captured in this photograph of a lightning strike?"
] | [
false
] | [deleted] | [
"I believe this is actually a facility designed to study lightning. They fire off a rocket and facilitate a lightning strike through a conductive aerosol or liquid emitted by the rocket during its flight. ",
"{Edit}: A bit of background awesomeness:",
"*",
"Video",
"*",
"The photograph in question",
"*"... | [
"I know some of the experimental details of this experiment.",
"The facility is a tower which effectively a lightning rod. A rocket is fired from the top of the tower, with a conductive tether on it.",
"A high speed camera 1M FPS is focused on the tower, and used to capture lightning strikes. the image you sh... | [
"It appears to be a ~5sec time exposure. The 'flames' aren't flames, theyre the motion-smeared lightning channel, captured while the shutter was open."
] |
[
"Regarding skin cancer, can it appear on parts of your body which hasn't been exposed to UV?"
] | [
false
] | [deleted] | [
"While it is possible to develop skin cancer from the natural accumulation of mutations or exposure to a carcinogen other than UV light, UV light is by far the most common cause of skin cancer. UV light exposure in one area will only affect the DNA of the cells that are exposed to it, and therefor can only create s... | [
"Judging by the extremely thorough examination my bud just got from his dermatologist (spread them) I'd say yes. UV can penetrate light clothing, a white TShirt only has an SPF of ten.",
"edit* A quick google search of \"Skin Cancer where the Sun Don't Shine\" brought me to ",
"This article",
" which brings u... | [
"YES.",
"\nThere are three common types of skin cancer (Melanoma, Squamous cell carcinoma and basal cell carcinoma... won't include adnexal tumors and so). All of them are somehow associated with UV light exposure, but there are several other causes, especially for Squamous cell. \nYou can get SCC after burns, ch... |
[
"Does the language you speak affect the shape of your palate?"
] | [
false
] | I was watching the TV show "Forever", and they were preforming an autopsy, when they said the speaker had a British accent due to the palate not being deformed by the hard definitive sounds of English (or something along those lines) does this have any roots in reality, or is it a plot mover? | [
"I don't believe there is any evidence to support that language affects palate morphology. However, vice versa it may be that morphology affected the development of (aspects of) languages.",
"For example, see these two paragraphs from a ",
"2015 conference paper by Moisik and Dediu",
":",
"It is an undeniab... | [
"I do know that in Russia, it's considered a prominent and full-blown speech impediment if you can't properly roll your R's - like how \"speech impediment\" to Americans usually means someone who can't pronounce a rhotic R properly. Vladimir Lenin was one person who couldn't do it, and he has dozens of impersonator... | [
"It is considered a speech impediment in every language which uses the roller R but is usually corrected by a speech language pathologist in childhood. It is the most common form of speech impedient in children, and it someone doesn't get it fixed and still speaks it like an adult, they should like a child. If some... |
[
"Can you tell me if there are really differences between male and female brains?"
] | [
false
] | Some say that male brains are more spatially aware and hence better at mathematics and driving cars, whilst female brains are better at emotional/linguistic construction and analysis. I heard that science can't actually classify brains as male and female however and that many people who are genetically of one gender ac... | [
"There is absolutely something in it. However, the waters are muddled a bit by experimental design. As it turns out, a woman's brain changes pretty dramatically depending on her cycle phase. Accordingly, unless you test your female subjects at the same cycle phase, it is tough to get clean results. Most studies so ... | [
"Yes, the ",
"sexually dimorphic nucleus",
" is a thing. It's part of the hypothalamus that's, among model mammals, quite a bit larger in males than in females, and appears to be involved in sexual behavior and preference. A corresponding region in the human brain is famously larger in heterosexual men, but sma... | [
"The monthly gray-matter fluctuations have been illustrated in video during lectures I have seen, and they are crazy-huge.",
"I'm very skeptical that gray matter volume is changing drastically on a times scale of weeks. The paper shows a concomitant decrease in CSF volume when GM volume increased, suggesting tha... |
[
"Does wind affect the distance sound travels?"
] | [
false
] | null | [
"Wind represents a gradient in atmospheric pressure. Low pressure brings wind (attempt to balance) from high pressure. Sound is a wave disturbance (oscillating pressure gradient). So if there's a large wind, there's a large gradient in pressure that will absolutely affect sound propagation through the medium..... | [
"You're forgetting that wind inherently mixes the air molecules around. Sound depends on one molecule linearly bouncing into the next molecule. And that happening over and over again, with a very large number of molecules, until the sound reaches your ears. ",
"A strong wind can literally blow the propagation of ... | [
"Sound is just a longitudinal wave in the air so yeah the motion of the air molecules will affect sound transmission. However, sound travels at like 300 m/s (in STP air, to one significant digit) so the effect is probably negligible unless the wind is very strong / gusty or the sound travels over a long distance (g... |
[
"Imagining the Tenth Dimension: How much of this video is scientifically sound?"
] | [
false
] | 's the video. | [
"The stuff up to three dimensions is pretty reasonable. The fourth dimension stuff gets iffy (although I hestitate to call it wrong), and the rest is just entirely nonsense."
] | [
"He's actually talking out of his ass, it's not even a real scientific theory."
] | [
"Actually, even the 3rd dimension stuff is pretty bad. They describe the 3rd dimension as the dimension in which curvature of a 2D surface is embedded. But you don't need to embed a manifold in higher dimensions for it to be curved. The best way to understand extra dimensions is as extra degrees of freedom. Rea... |
[
"If a cell was as big as a basketball, how big would an atom be?"
] | [
false
] | I'm trying to understand the scale of us, to the cell, to the atom, especially the scale of the cell to both of them. | [
"As a rough approximation, assume an atomic diameter of about 1 Ångström for a hydrogen atom = 0.1nm.",
"A bacterial cell has an average diameter about 1 μm (I'm using ",
"S. aureus",
" because it's roughly spherical). If it were an animal cell it would be about 20 μm (using a ",
"Macrophage",
"). ",
"A... | [
"Absolutely. And it assumes the atom is spherical, the cells are spherical, etc, etc. Back-of-the-envelope calculations are fun because you can make sweeping assumptions. :)"
] | [
"Great answer.",
"All this will depend on what you define as the diameter of an atom",
"I think the atom you pick is more significant than the details of how you define your radius!",
"Hydrogen: 1 Ångström.\nCesium: 6 Ångströms.",
"; )"
] |
[
"The geoid and the centrifugal force"
] | [
false
] | It is commonly said that due to the centrifugal force the gravity at the equator feels a little bit weaker than at higher latitudes. I understand what the idea behind this is. The centrifugal force is proportional to the distance to the axis of rotation which gets smaller as you go towards the poles. So at the equator ... | [
"Is the combined effect of gravity and centrifugal force the same everywhere on this surface?",
"Yes. If we were to ignore all the small-scale density-induced anomalies and only look at the major components of gravity as well as inertial forces due to the earth's rotation, then the value of ",
" at sea level (... | [
"When we say that gravity is weaker at the equator because of the centrifugal force, we imagine a perfect sphere. In other words, for a perfect rotating sphere, the geoid wouldn't be spherical.",
"Actually, the main reason the real geiod isn't spherical is because of the shape of the Earth, which is flattened at ... | [
"So gravity really isn't weaker at the equator on the actual Earth then?",
"So if we assumed a perfectly spherical Earth, and of uniform density, then clearly the gravity would be a little less on the surface of Earth at the equator. But if geoid was defined as it is now, it wouldn't be spherical, it would go abo... |
[
"Why are the colours/brightness often slightly different in each eye?"
] | [
false
] | null | [
"I don't think this is what op means, I have the same thing, it's more a white balance issue. My left eye has warmer colors than my right eye on, most noticeable when looking at light objects. Sometimes I notice it when I have both eyes open, just like when using red/blue 3D specs but not as extreme of course. It's... | [
"I suspect that the most likely answer is that when you close one eye, your pupil dilates as it would in a dark room. When you open that eye it takes a moment for the pupil to constrict again, meaning that more light is entering one eye than the other for a moment. This can be helpful when you have to turn on a lig... | [
"Are you female by any chance? You may be seeing differences due to X chromosome mosaicism combined with heterozygosity of the M and/or L opsin genes. "
] |
[
"What is the most addicting chemical/substance known to man?"
] | [
false
] | null | [
"Meth is amazingly addictive. Just for a little comparison, an orgasm releases 800 to 1200 units of dopamine in the brain, while your first time smoking meth releases around 40,000 units and can last upwards of 24 hours. This causes you to chase the original high, but never reaching it. Your dopamine receptors get ... | [
"yeah, you can die from alcohol withdrawals."
] | [
"There's a such thing as a lethal withdrawal?"
] |
[
"Can someone describe the nuclear shell model?"
] | [
false
] | I stubmled upon and found it fascinating. I remember learning in school about the atomic shell model and how electrons occupied shells at different energy levels. Is this analogous to the electron shell model but with respect to atomic nucleons? Do nucleons have orbitals or energy levels they can transition into and ou... | [
"Is this analogous to the electron shell model but with respect to atomic nucleons?",
"Exactly.",
"Do nucleons have orbitals or energy levels they can transition into and out of, and what application might this have (such as electron energy level transitions usually produce spectral lines and can identify eleme... | [
"Fascinating. As above so below. It seems to make sense to me that each layer is so similar but so much more complicated. "
] | [
"The attractive interactions are also much shorter range, which is why the number of bound states is limited (and nuclei have a maximum size). ",
"Electron orbits are also only weakly spin dependent where as nuclear energy levels are extremely spin dependent. "
] |
[
"How is the human brain responsible for 20% of our daily energy consumption? What does it primarily use it for?"
] | [
false
] | I've had this question for a while and I was curious how our brain allocates its energy consumption. Also does this standard 20% represent an average of all humans? Does this average change if we had a long day of exams (SAT, MCAT, Finals Etc.) ? The reason I ask is because I was going over the concept of Long Term po... | [
"What the brain primarily uses energy for is to pump ions across the membrane to re-establish the electrochemical gradient after action potentials and synaptic release.",
"There has been a lot of work on this area, and it would be very hard to summarize it in a reddit post. But I can show you the kind of estimate... | [
"As trying not to think is actually thinking a specific thought/command to yourself, this would intuitively seem to be counterproductive. "
] | [
"Lets say an axon has a surface area of 0.1 cm",
"I don't have any in-depth neurophysiology education, but this seems like the most likely place where you went too high. Wikipedia tells me the largest mammalian axons have a 10 micron (0.001 cm) radius. If the axon is a cylinder, then the area (not counting the en... |
[
"Does gargling water reduce the risk of catching or spreading a viral infection such as influenza or rhinovirus?"
] | [
false
] | null | [
"This is borderline scientific, but then again the question is too. Japan's Ministry of Health has ",
"deemed gargling ineffective in the prevention of the flu."
] | [
"As far as I know, the only medical/anti-disease use of gargling is to use Salt Water or other rinses to kill off an infection in your throat (ie, sore throat). Not my area of expertise, so I'm just posting what little I do know to keep your thread from being empty. :)"
] | [
"As opposed to America where the location of the planets when you were born effect your love life and luck for the rest of your life.",
"The point is there are non-scientific folks everywhere, regardless of the nationality. At least we teach science in science class and don't spend time trying to sneak the Christ... |
[
"What happens when you are \"seeing stars\"?"
] | [
false
] | To clarify, what I mean are those brightly glowing dots which swim around your field of vision for a moment after you've experienced some kind of shock, be it from getting hit in the face or jumping down from somewhere high. | [
"\"A ",
"Phosphene",
" is a phenomenon characterized by the experience of seeing light without light actually entering the eye.\"",
"Another quote from the Wiki article:",
"\"Phosphenes can be directly induced by mechanical, electrical, or magnetic stimulation of the retina or visual cortex as well as by ra... | [
"Great, but that doesn't answer the question at all."
] | [
"Of course it does. Stimulation of the retina by mechanical means causes the brightly glowing dots.",
"Mechanical means in this context is the shock from getting hit in the face. This causes the nerve cells in your eyes to fire even without light."
] |
[
"Antibiotic resistant bacteria are becoming an issue, why isn't research being done on bacteriophages?"
] | [
false
] | In my high school biology class, my teacher spent a week teaching us about bacteriophages, viruses that target bacteria, and how they could potentially replace antibiotics as a way to treat bacterial infections. Whya hasn't money been put into research on this? Is it unsafe? Is there some reason that it isn't liked b... | [
"they will have to design a phage that can evade immune response",
"And this, is a ",
" bad idea..."
] | [
"Not only that, but if it can evade the immune system it can easily share that information with other virues/bacteria via ",
"conjugation.",
"I'm sure we can all see why teaching bacteria and viruses how to hide from the immune system would be a bad idea."
] | [
"As far as I know, bacteriophage research IS being done. But the main reasons they are not effective as therapy is they will induce an immune response themselves and will be quickly cleared by the immune system. Bacteriophage therapy would either need to be taken multiple times each day, OR they will have to design... |
[
"Can someone explain why AC current fluctuates from positive to negative?"
] | [
false
] | My CNSA professor tried to explain it to me, but I just don't know why the electricity would flow differently based on where the coil is in its rotation (From 0 degrees to 180 and around to 360.). It has something to do with magnetic fields. When I compared it to (The wheel rotating in a circle while the strut moves ba... | [
"http://www.ncert.nic.in/html/learning_basket/electricity/images/machines/ac_generator.jpg",
"From the above diagram of an AC generator you can see that the wires are always hooked up in the same \"direction\" because of the slip rings. As the coil spins in the magnets the \"direction\" of the current changes. Us... | [
"I hope you get an answer because it's always been my understanding that transformers are useless in a DC circuit. If the electrons aren't sloshing back and forth there is no changing magnetic field to induce current in the other/secondary coil, so a transformer effectively breaks the circuit and nothing happens."
... | [
"It's my novice understanding that AC is used because it's easier to step up the voltage via transformers. Higher voltage means the same amount of power can be transmitted using less current, according to the formula Power = Voltage x Current. Less current means less resistance in the lines and therefore less power... |
[
"How can basic geometric shapes be manufactured from primitive tools?"
] | [
false
] | I have been trying to think up a way one could make things like spheres, planar surfaces, cylindrical columns, or cubes with the natural raw materials/tools of the earth (gravity, rocks, water, fire, plants, etc). I'm having trouble thinking of a method that doesn't leave it up to subjective observation and adjustment.... | [
"Use strings or cables of some sort. If you want a plane, stretch a piece of string (maybe animal gut or woven from fur or reeds) over an arched stick, the stretched piece of string will be almost perfectly flat, and you can use it to help you judge the flatness of a surface you are carving. If you want a circle, a... | [
"Additionally: loop of string, two fixed points (tacks on a plane): ellipse.\nString hanging down with something heavy attached: straight line, use it to make something firm and straight, a plank, for instance.",
"With plank and string, you have a ruler and a compass. All of classical geometry is in your hands. T... | [
"Can you elaborate on your question a bit? I'm particularly unclear on what \"leave it up to subjective observation and adjustment\" means.",
"But just taking a stab, if you're suggesting that it's possible to construct geometrically perfect macroscopic objects with ",
" tools, primitive or not, you're mistaken... |
[
"How is it that people who can't speak a word of English can sing in perfect or almost perfect English"
] | [
false
] | As title says. I have been wondering this for awhile. | [
"You learn it phonetically. ",
"I sing the non-english parts of this ",
"song",
" all the time. ",
"Don't have a clue what any of it means."
] | [
"Yeah, I can sing most of Rammstein's songs but I only know like 10% of the German language "
] | [
"Sure they can.",
" "
] |
[
"Does gravity have a range?"
] | [
false
] | This might be a stupid question, but I'm curious about the range of gravity. When we say we are in zero gravity are we actully that or is the gravity forces just so low, that they have no practical effect? If there is a max range, how far should I be from an object with the weight of 1, before it would have no effect o... | [
"Falling but missing."
] | [
"No, gravity affects any object, no matter the distance. But at some point, it will not be noticeable at all.",
"When talking about \"zero gravity\", you probably mean a space station or something. First, usually the term is \"micro gravity\", and second, there is quite a lot of gravity out there. The astronauts ... | [
"Orbit is freefall. Their velocity perpendicular to the direction of Earth's gravitational pull is such that they move around the Earth at the same rate they are falling towards it."
] |
[
"Is it possible to isolate the particles of a virtual particle pair?"
] | [
false
] | null | [
"Virtual particles should not be considered to be \"real\" particles, but it's complicated. The most obvious reason is that they don't need to obey the energy-momentum relation,",
"which all \"real\" particles have to by definition. But we can say more: When say two particles interact, their interaction is a terr... | [
"In the original paper, nothing was said about virtual particles.",
"What you need to know is that particles are actually vibrations in quantum fields, and black holes cut off some ways of vibrating, so other vibrational modes that were originally cancelled out now aren't, which means there are now particles."
] | [
"Thanks for your excellent answer"
] |
[
"How do we know the exact age of the earth?"
] | [
false
] | When i searched online i found that the method used to calculate the age was radiometric-dating, but then we should only know that the earth is as AT LEAST as old as the oldest rock that was dated. where did the upper bound on Earth's age come from? | [
"Meteorites. The idea is that dating primitive meteorites allows us to date the time that the solar nebula began to condense to form planets and other rocky objects, thus dating meteorites give us a date for planetary formation (and not just Earth, all the planets). There are myriads of write-ups on this topic writ... | [
"Thanks for the explanation and the links, so if i understand correctly, meteorites are the building blocks of earth and all the other planets in the solar system and by dating it, we get the upper bound on the age of earth "
] | [
"Earth Sciences"
] |
[
"How efficient are solar cells, compared to biological systems that collect solar energy?"
] | [
false
] | I realize this is kind of a vague question. Want I want to know is if we can ever replace solar cells with some kind of biological system that collects sunlight in a way like the cytochrome-like proteins do. Could you convert the chemical energy into electrical energy that we can use/harness? | [
"We already do this with power plants that burn biomass. The plants grow in the sun and we burn the plants. The chemical energy is turned into heat which powers a rankine cycle which generates electricity."
] | [
"Unfortunately this is using dead plants or soon to be be burnt to a crisp plants and generates some pollutants. I'm thinking more a long the lines of a living system that we could tap in to without killing the cells.",
"Or maybe even just stealing the type of machinery cells use to collect sunlight and bypassing... | [
"Meh, as long as you can create the machinery that makes a proton gradient from sunlight, turning this into useful electrical energy seems relatively straightforward and could probably be made extremely efficient (you're just talking about an electrochemical cell).",
"Also improving on the inefficiencies of plant... |
[
"What is stress?"
] | [
false
] | This word gets thrown around a lot. What counts as stress? What exactly goes on to your body or mind when you are stressed? | [
"stress is a response to insults that can be mental or physical. Whether it's pain, starvation, psychological distress etc. It's basically the body's response to these stimuli which can disrupt homeostasis.",
"basically stress in the body activates the flight or fight response and releases hormones like cortisol ... | [
"Stress can be a difficult term to define, but physiological stress would be the body's response to any factor (\"stressor\") that threatens the health of the body or has an adverse effect on its functioning e.g. injury, disease, overwork, worry or sense of danger.",
"The initial registration and processing of st... | [
"Stress is your body's way of responding to any kind of demand. It can be caused by both good and bad experiences. When people feel stressed by something going on around them, their bodies react by releasing chemicals into the blood. These chemicals give people more energy and strength, which can be a good thing if... |
[
"Is the range of gravity infinite? Is the Earth technically (but insignificantly) helping slow the expansion of the Universe? Or does each object's.. \"well\" have a finite range of what it affects?"
] | [
false
] | null | [
"In short, there is no absolute limit. However due to relativity and laws of causation there actually is a limit given by the speed of light. That is to say if Earth magically doubled in mass in an instant(t=0) observers at varying distances from Earth would feel the increased gravity a some time t>0 depending on h... | [
"obviously the universe can't expand fast enough for an object at a finite distance from earth to move away from it at the speed of light",
"Nope, that's exactly what happens. The speed at which two objects are pulled apart by expansion is proportional",
" to their distance, so if they're far enough, it does ex... | [
"This leads to a question I've never thought of before: obviously the universe can't expand fast enough for an object at a finite distance from earth to move away from it at the speed of light, but will the furthest reaches of the universe eventually approach such speeds relative to us? Will that affect how we inte... |
[
"How do we know that planets like Jupiter are composed entirely of gas and not rocky planets with a thick atmosphere?"
] | [
false
] | It seems like no planetary survey missions have attempted to plunge into the gas giants and return more detailed information than is available by terrestrial/space astronomy or flybys with probes. Is there a possibility our understanding of gas giants is incomplete? Would a rocky core be a necessary "nucleus" for gathe... | [
"A quick search of \"gas giant cross-section\" shows that Jupiter and other gas giants are often depicted as having a solid rocky or iron core. That matches my half-remembered college classes. And here's a paper that models the formation of gas giants as solid cores which then attract gasses",
"http://www.resea... | [
"There's also a ",
"Wikipedia article",
" on \"mini-Neptunes\" or \"gas dwarfs\", which would be closer to the idea of a \"rocky planet with thick atmosphere\". It doesn't appear that they have been thoroughly proven to exist yet, but there's several detected exoplanets with mass and density values that seem t... | [
"Europe \n ",
"Do you mean Europa?"
] |
[
"Why am I allowed to pour acids into water but I'm not allowed to pour water into acids?"
] | [
false
] | This is a rule in our chemistry laboratory. | [
"To add to AgentAsterisk, the exothermic reaction caused by adding the water can cause the water to boil immediately causing a sudden expansion of gas; naturally a sudden expansion of gas would at least splash acid everywhere."
] | [
"To add to AgentAsterisk, the exothermic reaction caused by adding the water can cause the water to boil immediately causing a sudden expansion of gas; naturally a sudden expansion of gas would at least splash acid everywhere."
] | [
"What I find concerning here is that the student either did not ask the teacher why, or the teacher answered “because that’s how we do it”."
] |
[
"Why do we see the milky way as having a black strip running through it?"
] | [
false
] | I saw image on and couldn't help but wonder: why does the milky way appear to have a black stripe across it? I mean, shouldn't we see the center as a glowing ball? Is there something in front of it (a gass cloud, something else) or does it have a peculiar shape that is not easy to spot at first? edit: is how i see it n... | [
"The Milky Way's spiral arms are filled with dust. Our solar system is in a spiral arm. As we look toward the center of the galaxy, our view is obscured by this dust."
] | [
"JWST will do exactly that. Unfortunately, it probably won't actually be that pretty - most of the cool pictures of galaxies are cool because of all the gas and dust lanes have interesting structure. If you can look through the gas and dust to only see the stars, you'll generally just see a smooth distribution of s... | [
"Just imagine how sexy it would be to be able to see the center of our galaxy without all that garbage."
] |
[
"Can talking parrots have accents like us?"
] | [
false
] | null | [
"Yes and no. Not in the way you probably mean and not on their own. \"Talking\" parrots imitate the sounds they hear, including speech. If the speaker they imitate has an accent, the parrot also imitates that accent. They don't create their own accent.",
"However, wild living parrots can apparently have some kin... | [
"Parrots and other types of birds that can be taught to speak are really just adopting sounds of human speech as their \"calls\". They technically aren't communicating in the language they're producing, just very accurately reproducing it. Only rare cases, like A",
"lex, the African Grey parrot who died some time... | [
"Thank you!"
] |
[
"Why do coniferous trees only seem to proliferate in mountainous or northern environments?"
] | [
false
] | I live in the Eastern United States. The only time I ever see conifers or "pine trees" is at Christmas or in the occasional wild grove or landscaping area. Yet out west in the Rockies, British Columbia, and everywhere in southern Alaska, conifer forests dominate, even at low elevations. Why is this? EDIT: Thanks for yo... | [
"Conifers can grow just fine in temperate climates, but they'll usually get outcompeted by those faster-growing broad leafed deciduous tree like oak, maple, etc. But they have adaptations which allow them to do much better in colder climates than their broad-leafed competitors: their sap contains antifreeze like co... | [
"This, however I will add a few facts.",
"Most of them are adapted for conditions with short summers and long winters, making the waxy coating (water loss resistant) and design of the needle (wind damage resistant) a benefit. Because these needles are hardy, they don't shed much and take a long time to break down... | [
"There's also the whole can of worms of disturbance regimes, fire regimes in particular. In many places the very high density pine dominated forrest you see in the temperate regions west aren't completely natural.",
"Before Europeans came many of ",
" the pondersosa pine",
" forrest in the west were actually ... |
[
"Why do clones die so quickly?"
] | [
false
] | For example Dolly, or that extinct Ibex goat that we tried bringing back. Why did they die so quickly? | [
"Dolly the sheep didn't die from cloning related complications, and she lived a long enough life to give birth to 6 lambs. Ultimately she died of lung cancer caused by Jaagsiekte sheep retrovirus (JSRV), a virus that was infecting the rest of her herd. She was euthanized due to the tumors in order to prevent her fr... | [
"Hmm, most clones don't make it until birth, and there are numerous explanations, largely depending on how the cloning was undertaken.",
"Typically, as with your examples, a process called ",
"somatic cell nuclear transfer",
" is undertaken. In short, cells are taken from adult animal, the nucleus containing ... | [
"Her offspring is doing just fine! Four of them have lived to be 7-9 years old or 60-70 in human years. Proof that clones can live a normal healthy life. ",
"-Source-"
] |
[
"How many plants/trees would it take to sustain one average person's O2 needs and vice versa?"
] | [
false
] | As an example, Sandy from Spongebob Squarepants lives in a dome with a tree... How much foliage would actually be required to keep a healthy O2 level? | [
"Here an ANL scientist answers the question: How many plants are needed to make enough oxygen for one person for one hour? We are experimenting with Anacharis plants.",
" Check out the link, but the end result is: \"these are round figures, let us just say that between 300 to 400 plants are needed to produce enou... | [
"That link isn't quite correct in the assumptions. Not 100% of oxygen we breathe in is converted to CO2. Humans actually only use 5-7% of the 21% oxygen we inhale, exhaling a mixture that contains ~14-16% oxygen. This reduces the number of plants one needs by a factor of four, so closer to 80-100."
] | [
"By vice versa, I meant CO2 from the person to the greenery"
] |
[
"What is meant by the following statement which appeared in a physics article yesterday regarding the diphoton hangover? \"The absence of new particles almost certainly means that the laws of physics are not natural in the way physicists long assumed they are.\" [link in comments]"
] | [
false
] | I have an engineering degree level of physics understanding and am not religious so there is no need to address concerns regarding physics possibly being "unnatural". | [
"The article does explain what this means, in the \"Missing Pieces\" section. But I'll give it a go too.",
"The miracle of physics is that in everyday life we don't need to understand how Nature behaves at energies much higher or distances much smaller than we're interested in. So to study fluid dynamics you gene... | [
"I love this response because I know very little about the field and you have explained it to the point that I understand. Thank you for this. :)"
] | [
"Thanks, that made my day! :)"
] |
[
"Is drinking artificially sweetened, carbonated water, in any way, less healthy than plain tap water for daily hydration needs?"
] | [
false
] | Is there any reason why someone might want to avoid drinking products like Fruition, which is just artificially sweetened and flavored, carbonated water, as a substitute for plain water? Does the body have to "work harder" to extract the water or are there any health hazards associated with the extraction of the CO2 fr... | [
"The body couldn't work harder, since water is absorbed passively as far as I know. But since sugar/carbohydrates bind water (as do electrolytes and alcohol and many other things), you won't get as much hydration from sugary (or salty or alcoholic) water than from the same amount of pure water.",
"I can't imagine... | [
"Great, thanks. That's what I was hoping would be the case."
] | [
"Coke is artificially sweetened, carbonated water. Why wouldn't you drink that?"
] |
[
"How is it that I sometimes see the most spectacular pictures of the milky way, but when I am i a desolate area I never see anything remotely like it?"
] | [
false
] | null | [
"Aloha from the Big Island of Hawaii where I am currently sitting in one of the worlds largest optical/IR astronomical observatories.",
"First, as you have already pointed out - long exposure times are used to get the detail we need. The other day we were observing Messier 15 and the exposure times were on the o... | [
"You will never see it as clear as in that picture. As someone who frequently does night photography, cameras will not only show details better, but will also render colors more vividly as humans don't have good low light color perception. ",
"Also, that picture is heavily edited. It would look quite diffrent in ... | [
"You may be in the wrong hemisphere. The southern hemisphere gets a much clearer shot at the milky way than the northern, as the south pole points at the center of the galaxy, where you get those nice dense-looking clusters, and the north pole points away from it. "
] |
[
"Why does the equilibrium constant change only when temperature changes?"
] | [
false
] | [deleted] | [
"You have two reactions, one going A -> B, and the other going B -> A. The more A there is, the faster reaction 1 goes. The more B there is, the faster reaction 2 goes. This reaches a point where 1 is happening as fast as 2, so there is no net change in amounts of A and B. The equilibrium constant is the ratio of t... | [
"When you change the temperature you change the relative stability of the products and the reactants. The thing is though the relative stability does not change equally. As temperature goes up the product stability might increase at a slower rate than the reactant stability and as a result the equilibrium will sh... | [
"Partial pressures are another way of talking about concentrations for the gas phase. There's no magical reason why the pressure has to stay constant (you could pump inert gases into the container and raise the total pressure), but if you increase the partial pressure of a reactant, the reaction rate for getting ri... |
[
"Why don't meadows have bushes/trees like the land that typically surrounds them?"
] | [
false
] | null | [
"There are several causes for lack of trees. ",
"The meadow may just be in an early successional state where trees haven't grown back yet. This would be due to a disturbance like a fire or landslide that killed the trees that had been there previously.",
"The meadow could be growing in a location where the en... | [
"A biologist friend of mine loves to point at the boundary between trees and grassland and say “see that? That’s a war zone.”",
"Trees evolve inhospitable toxins in their leaves that they drop on the ground below, and ally themselves with fungi in the ground that make it hard for grass to grow. Similarly, grasses... | [
"This is supporting what you've said, but there's an interesting case in the Allegheny National Forest. ",
"Prior to the NF being created, the area had been clear-cut from a ~300 year old forest (the 300-year-old forest had grown back after a major wildfire). Once the national forest was created and they s... |
[
"What makes stainless steel \"food grade\"?"
] | [
false
] | Maybe some simple questions, but what makes stainless steel so good for food processing? Is it possible to do something to an old stainless piece of equipment to make it "food grade" again? What if the equipment was previously used in medical/hazmat/industrial settings? Does that matter? I see from "The most widely u... | [
"Food plant mechanic here. 316 is typically used where direct contact with food is required. Incidental contact areas like machine frames are typically made from 304 or 308 because it is cheaper. 316 is incredibly stable and corrosion resistant. 304 is similar, but not of the same quality. Some minor corrosion can ... | [
"I assume it is because 316 SS costs more to manufacture. "
] | [
"You can use whatever stainless you want. The worst that could happen is that you will get a little corrosion (rust) with a less corrosion-resistant steel. Fortunately, a little rust never hurt anyone. Cast iron rusts like crazy, and has been used safely in cookware for centuries."
] |
[
"Why doesnt AIDS burn itself out?"
] | [
false
] | [deleted] | [
"First, you need to make the distinction between AIDS and HIV. HIV is the virus that causes AIDS. AIDS is the state of immune deficiency caused by the HIV virus. People can be HIV positive for years or a lifetime and never developed AIDS, which is defined as having fewer than 500 CD4 cells per microliter of blood. ... | [
"What the other answers missed is that HIV-1 does ",
" do that, i.e. run out of cells to infect. When this happens in late stage disease the virus can undergo what's called a tropic switch. ",
"Almost all HIV-1 infections start out using the CCR5 coreceptor to infect T cells. But CCR5 is only found on a fractio... | [
"state of immune efficiency",
"You mean deficiency?"
] |
[
"How similar is mitochondrial DNA across species compared to the actual DNA of the species?"
] | [
false
] | I know that nearly all eukaryotes contain mitochondria in their cells, and that similar species share large portions of their genetic code, so this made me wonder - how similar is the DNA of mitochondria across species? Is the DNA of my mitochondria closer to chimpanzee's mitochondria than my DNA is to a chimpanzee? Ho... | [
"Mitochondrial DNA (mtDNA) contains some of the genes that are necessary for the oxidative phosphorylation that occurs inside mitochondria (genes such as ATP synthase, NAPH dehydrogenase, among some others). Since these genes are important for any organism that relies on oxidative phosphorylation (the process of sl... | [
"At this point is pretty much a fact. "
] | [
"Er, chloroplasts, as well as all other plastids."
] |
[
"Voyager 1 is about to be the first man-made object to leave our solar system. Couldn't we just send a probe out orthogonal to the plane of our solar system in order to enter interstellar space faster? Why haven't we done this?"
] | [
false
] | Just wondered about this after reading the other thread about Voyager I. Thanks. | [
"One of the advantages of flying within the solar system is the possibility of gravity assists. These allow a spacecraft to speed up without spending too much fuel. If we wanted to launch a probe orthogonal to the plane of the solar system, it would have to rely on its own propulsion only.\n",
"Brief description ... | [
"Ah that makes sense. After posting I also realized that we probably wouldn't want to waste the opportunity for close fly-bys/observations of most of the other planets in the solar system on the way out."
] | [
"I had a similar question from that same thread.",
"Could we not attach a rocket to the probe, and circle it around our planet to pick up speed by gravity, then fire up the rocket to break out of orbit and continue into space, with the rocket still burning giving it more propulsion, and I assume that it would mai... |
[
"Why are there complex secure deletion algorithms with multiple passes when I can simply write 1's or 0's to my data?"
] | [
false
] | null | [
"To answer this, it is necessary to make a distinction between the abstract service which a computer presents to its users (which is digital in nature) from the physical implementation (which is analogue).",
"So far as the abstract machine is concerned, once you have overwritten it with zeros then the data is irr... | [
"Solid state drives typically store data as a charge on a floating gate, and do suffer from data remanence.",
"However, as I indicated above, there is a bigger problem if you try to zero it because there will usually be a storage controller between you and the flash chip, and the controller is likely to implement... | [
"From what I remember Secure erase is to completely remove any of the original bias. Normally the device only reduces the charge to below threshold but doesn't completely discharge it. This means that it can still be read with the right equipment. ",
"This sort of thing is used on all types of memory and even som... |
[
"What was the most powerful volcano ever known to mankind?"
] | [
false
] | null | [
"Mason et al, 2004",
" provide a review of the largest explosive volcanic eruptions, their ultimate goal is to understand the frequency of eruptions of different size (it is worth noting, this compilation focuses on explosive eruptions, so thinks like ",
"Calderas",
", as opposed to systems like ",
"Large I... | [
"If you're looking for recorded history, you probably want to look at ",
"Krakatoa",
".",
"Some highlights:",
"Ships as far away as South Africa rocked as tsunamis hit them, and the bodies of victims were found floating in the ocean for months after the event. ",
"In the year following the eruption, avera... | [
"Even something like a small hurricane generally releases more energy than a nuclear weapon! Nature is real crazy.",
"https://earthobservatory.nasa.gov/features/Hurricanes"
] |
[
"Why does fire change colour with certain chemicals inside it?"
] | [
false
] | null | [
"The color represents electron transitions between orbitals on the vaporized material (i.e., the fuel, the combustion byproduct etc.) Different materials have different energy levels for their electrons. The transition between these levels produces unique wavelengths of light. Taken in aggregate, these are the co... | [
"Is \"different energy levels\"a fancy way of saying hotter or colder? I have always thought the color was indicative of the amount of heat. I.e. Blue flame hotter than yellow flame. "
] | [
"Imagine the atom as a roundabout (or traffic circle, whatever) with multiple lanes that the cars can never leave. There are different amounts of cars in each lane and they go at different speeds. When some cars decide to go faster, they have to use more energy and move to a more outside lane. Eventually they can't... |
[
"Special relativity from multiple simultaneous perspectives?"
] | [
false
] | : Due to special relativity, if one atomic clock is on a space-craft moving very quickly (closer to the speed of light I suppose), and another atomic clock is on the planet standing still, the time on both of them will appear different. : How does this reconcile with multiple points of view of the same phenomenon? For ... | [
"In order to explain time dilation, let me fist explain what it is ",
". A popular, but entirely wrong notion of time dilation states, that time passes slower the faster you move. A quick examination of this claim, however, reveals that it cannot be true. There is no absolute velocity, so velocity only makes sens... | [
"The two observers would not agree about the distance traveled due to length contraction."
] | [
"That's actually the core point of special relativity - that events do happen at different times and in different locations from different frames of reference. For instance, when a space-craft is moving quickly away from Earth, Earth sees the clocks on the space-craft as ticking more slowly. But from the space-craf... |
[
"Is it possible to edit the contents of a hard drive without using a computer?"
] | [
false
] | Like, is there any way a person could change, add or delete files with relative precision on a hard drive without going through any kind of system? I'm not talking about microwaving a hard drive and destroying everything. I'm wondering if selective, relatively specific changes can be made to digital storage devices wit... | [
"This would not be practically possible for multiple reasons.",
"Even if you somehow had a way of physically making the kind of physical changes with the incredible precision that a software-assisted hardware is able to do when storing information, a person would still have to know how a file (or anything meaning... | [
"The real problem is the scale of the storage devices. Suppose you sit down to read through the contents of a modest 500 GB hard drive at 200 bytes per minute, which is probably a pretty fast pace for someone reading and trying to understand binary opcodes.",
"You finish in 4,756 years. The human brain is an amaz... | [
"As far as I can tell, the answer would be \"maybe\". ",
"As in, it's physically possible in a way. But that would require four things: one, a custom-made machine capable of accurately targeting the individual bits on the hard disk drive, with the hand-operated controls to trigger specific bits. (So, for all inte... |
[
"Does the diffusion of different substances in a solution depend on the other substances?"
] | [
false
] | I am studying cellular biology; specifically, diffusion involving cellular membranes. Thanks! | [
"Diffusion expert here about to embarrass myself while sleepy. The answer to your question is yes, always. However, often the effect of solutes on each other is so small that there is no harm in ignoring it.",
"To determine whether you can ignore the effect of different solutes on each other, you need to understa... | [
"In a multicomponent mixture diffusivity is defined by the pair component-mixture, which ends up depending on its composition. For example in a ternary mixture involving components A, B and C, the instead of diffusivity D_AB you define D_A-MIX which is the diffusivity of A in the mixture of A, B, C."
] | [
"This isn't true.",
"Diffusion is the movement of dissolved components in solution along concentration gradients (from high concentration to low concentration).",
"Even if (in your example) A had affinity to B, B would still be subject to the same principles guiding diffusion, that being the concentration gradi... |
[
"How easy or plausible is it to transfer location/schools once you have entered a PhD program at one?"
] | [
false
] | So I'm 21 and a male, in the US. This past month has been my first month in a Graduate program for biochemistry and biophysics. While I'm still questioning my decision to go to grad school, I am unhappy due to the location of the program. I shot myself in the foot in choosing to move halfway across the nation for this,... | [
"People do it, infrequently. But essentially you're applying to a new program all over again. Find an advisor at the school you want to work at, and talk to them specifically.",
"Edit to add: If you're questioning being in grad school at all, leave and don't come back until you're sure. No one needs a grad stu... | [
"Do you have your own funding? It's far easier to talk to a new advisor when you can say that they won't have to pay your salary. If someone agrees to take you, it's much easier to get into a department.",
"If you don't have your own funding, it will be a bit more difficult but still manageable. You need to re-ap... | [
"I know you may not know the answer to this question, but will that not scar my record, such that grad schools in the future may look down upon me for leaving once?",
"This is a legitimate fear of mine... "
] |
[
"How does the \"Doppler effect\" work for an accelerating source?"
] | [
false
] | I came across and am trying to imagine what it would look like for an accelerating object, like a jet. How would the shock front of an object with a constant and/or non-constant acceleration behave? | [
"A stationary source, like a radio sitting on a table, will sound normal. A radio moving toward you will have its sound waves appear closer to one another, like in the gif you linked to. This sound wave compression gives the radio music a higher frequency, which we percieve as a higher pitch.",
"If you mounted a ... | [
"The difference between the two scenarios is that the first (car moving straight toward you) involves you standing on the path of the car. The second (the one in the diagram) involves you standing off to the side of the road.",
"If you're standing in the middle of the road, and a car moves toward you, you'll hear... | [
"That's the difference I was trying to explain (badly, apparently). A sound source that's moving at a constant speed (or at rest) will have a constant pitch to a listener. A car that's honking its horn and moving straight toward you will have a high pitch that doesn't change (because its speed doesn't change). If a... |
[
"Why is the spectrum of an incandescent lightbulb the way it is?"
] | [
false
] | null | [
"It’s not half of a Bell curve, it’s a black-body curve. That’s approximately the spectrum of any thermal radiator at equilibrium."
] | [
"oh ok, thanks. Do you know why it looks that way?"
] | [
"You can find derivations of Planck’s law online. It’s a little much to summarize in a Reddit comment, however."
] |
[
"What are the advantages and downsides of an Ion Propulsion system over conventional spacecraft propulsion systems, like liquid fuel?"
] | [
false
] | null | [
"There are several things that are interesting with ion thrusters and electric propulsion systems for spacecraft in general. ",
"The most obvious one is that they can accelerate propellant to much higher speed. This means that the certain quantity of propellant will generate more impulse. Impulse is the thrust ti... | [
"Yep, xenon production is a dozen tons a year. Starlink probably has in the order of 10 to 20 kg (I haven't done the math) so they would definitely have a supply issue so no surprise there. Krypton is nearly as good and much more abundant so it makes sense if you are developing a thruster from the ground up like th... | [
"Would would to solar panels sail effect be stronger than the ion thrusters?",
"Nah, solar pressure is way way below the thrust you get from an ion thruster. This is why they are used all the time and solar sails have been only done for very limited experiments so far.",
"Also are radioisotope generators used f... |
[
"If we are running out of oil, how can gas prices be going down?"
] | [
false
] | null | [
"The short answer is time frame. We are running out of oil, but not for hundreds of years. So what is driving prices down is that we are pumping more oil out of the ground than is being used and competing companies and countries have decided not to stop pumping it out in an effort to break one or the other. So wha... | [
"The good ole' supply demand rule in effect. You don't want to pay a lot for something you have huge quantities of. ",
"OPEC",
" don't want to put a lid on supply (how much is produced) due to the increased energy production through other sources (e.g. renewables and shale gas). This means that oil producing an... | [
"Pretty much more supply than demand, causing a surplus of oil in the market of oil, which causes a fall in price because businesses are trying to get rid of their excess oil that cannot be sold at the previous price."
] |
[
"People in the 1500's used mercury as a cure for syphilis. How did they obtain it? How and why did they decide that mercury was the answer?"
] | [
false
] | My source text is Bill Bryson's "At Home." Among many other topics, his book covers venereal diseases and their purported cures. Mercury has been mentioned as a cure for other general maladies as well. Why mercury? How did they obtain it? Why was it considered to be a miraculous cure, when it would seem to exacerbate t... | [
"To get Mercury you just have to find some Cinnabar (red rock) and heat it up."
] | [
"Why use mercury?\nBecause it was a strange material that was unlike many others. They thought it had some essence of life to it. People did a lot of things back then that we look back and consider very odd or ill-advised. Similarly, 400 years from now, people will look back and shake their heads at the stuff our ... | [
"Why use mercury?\nBecause it was a strange material that was unlike many others. They thought it had some essence of life to it. People did a lot of things back then that we look back and consider very odd or ill-advised. Similarly, 400 years from now, people will look back and shake their heads at the stuff our ... |
[
"How is continental drift measured so precisely?"
] | [
false
] | A drift of, say, 2cm/year requires an extremely accurate measurement. Googling tells me that laser-equipped satellites are used. But wouldn't atmospheric distortion and slowing of the beam cause errors greater than what is required to measure such slow motions? Not to mention determining the satellite position so accur... | [
"The first measurements of continental drift were actually made by radio astronomers using ",
"very long baseline interferometry",
"."
] | [
"Many times we use GPS sensors to give absolute data in the current day, such as for ",
"the Basin and Range Province",
" (PDF warning!). However, there is one point that a lot of people get confused about: These readings are for the ",
". ",
"This means that if you look at the GPS and satellite slip comp... | [
"This is incorrect.",
"\n",
"Error Propagation in Addition and Subtraction",
"\nOr a more generalized look:",
"\n",
"Propagation of Uncertainty"
] |
[
"How can scientists tell how old light is?"
] | [
false
] | I've heard numerous claims of 'the light has been traveling x long to get to us'. But for something on the order of billions of light years away, I'm pretty sure you can't use parallax to measure how far away the light source is....furthermore, it is my understanding that because of expansion, a lot of stars were not a... | [
"For these kind of distances the most popular way is to use a particular type of super novae. The progenitor system of these SN is usually a white dwarf and a larger companion. The white dwarf sucks in matter from the companion star until it reaches some critical limit and then goes super nova. This happen always a... | [
"Don't mix up Doppler shift and cosmological redshift."
] | [
"Don't mix up Doppler shift and cosmological redshift."
] |
[
"Would quantum computers be better at predicting the weather accurately?"
] | [
false
] | Umm yeah the title pretty much says it all, if quantum computers became a thing would they be way better at predicting the weather than what we have now? | [
"I am under the impression that weather forecasting runs up against turbulence rather quickly. In that case, I think it's difficult/currently impossible to create accurate models generally which is a necessary precursor to creating algorithms to run said models.",
"But about quantum computers, they are not able t... | [
"This. While computational power is of course a problem with any model, the primary problem is the improvement of the model, not necessarily the computer. If the models used to predict weather improve, then the accuracy will be better, regardless of what it runs on.",
"The possible speed improvement of quantum co... | [
"The real problem with weather predicting is that Earth is inherently a chaotic system (chaos here coming from chaos theory). The nutshell of chaos theory is that while the system behaves deterministically (ie if you know the current state exactly you can predict state of the system in 5 minutes), small uncertaint... |
[
"How do human vocal cords hit such low notes when strings and wind instruments have to be many, many times larger to do the same? Put another way, why are there no tiny bass instruments?"
] | [
false
] | null | [
"The difference between our vocal chords and string/wind instruments is that our vocal chords physically vibrate at the particular frequency through muscular tension, while strings and winds produce a longitudinal wave along their entire length that vibrates at the particular frequency. So for a string/wind instrum... | [
"A speaker, or a pair of headphones is an example of how a smaller device can produce bass notes via vibration "
] | [
"I think you have misrepresented the problem.",
"While the vocal cords themselves may be \"tiny\" (arguable) the human voice is composed (hah) of far more than merely the vocal cords.",
"After the sound is generated by air moving over the vocal cords, the resulting vibrations have their resonances and volume de... |
[
"AskScience AMA Series: We're the New Horizons mission team that conducted the farthest spacecraft flyby in history - four billion miles from Earth. Ask us anything!"
] | [
false
] | On New Year's 2019 NASA's New Horizons flew past a small Kuiper Belt object named Arrokoth, four billion miles from Earth, in a vast region home to the icy, rocky remnants of solar system formation. Our team has new results from that flyby, and we're excited to share what we've learned about the origins of planetary bu... | [
"How far in the distance/future have you plotted the course, such as including other objects gravitational effects, etc?",
"Or is this insignificant past Pluto on this scale?"
] | [
"We do plot our course for years in advance! We do that with complete models of the gravity of the Sun and planets. - SAS"
] | [
"Dwarf planets are planets too! --Bill McK."
] |
[
"How come mosquitos do not spread blood borne diseases like HIV and Hep C?"
] | [
false
] | null | [
"Mosquitos do not inject blood when they bite. Just saliva. So for most blood borne viruses like HIV, the virus can not replicate in the mosquitos digestive system, and never makes it into its saliva. ",
"Malaria on the other hand is essentially designed for transmission by mosquitos. it grows and reproduces in t... | [
"So theoretically could hiv adapt to take advantage of mosquitos or is it outside the abilities of a virus"
] | [
"Surely the mosquito mouthpiece will have bacteria and viruses on it ? Sharing a needle can transfer AIDS, how come a mosquito needle can't ? "
] |
[
"If glaciers hold approx. 70% of the worlds freshwater, and the glaciers are melting. Does all freshwater retreat to the ocean and is lost forever?"
] | [
false
] | null | [
"Well no, not in the way you describe it. It's true that the freshwater of the glaciers is lost for consumption, as it becomes salty, but most of the earth's glaciers aren't used for freshwater production (some of them are in a very tiny amount). So it wouldn't have an influence on the current freshwater productio... | [
"Two questions: If all the glaciers melted for whatever reason, would the oceans salinity be affected and if so how would the human race be affected? 2. Mars' ocean evaporated (so some scientists say), why couldn't ours? Granted, it wouldn't be overnight...."
] | [
"Two questions: If all the glaciers melted for whatever reason, would the oceans salinity be affected",
"Yes, but not strongly, see this ",
"picture of water distribution on earth",
". Most water already is saltwater and almost one third of freshwater is not bound in glaciers or ice caps. ",
"Humans would b... |
[
"Are we using energy when we think? If so how much?"
] | [
false
] | I was in a lecture the other day after a poor night's sleep and came across a pretty basic math problem that I could usually do in my head. I started working it out and then 3 seconds later decided I couldn't be bothered, which made me wonder, do we use up energy when we think hard enough just like we use energy when d... | [
"I have unsuccessfully tried to find a source on any actual numbers when this question comes up on the subreddit every couple of months. Do you have any primary literature for that ~100 Calorie measurement?"
] | [
"I have unsuccessfully tried to find a source on any actual numbers when this question comes up on the subreddit every couple of months. Do you have any primary literature for that ~100 Calorie measurement?"
] | [
"Yes, but you have to have low blood glucose for quite a while before your brain resorts to utilizing ketones as a source of energy. Glucose is far and away the brains preferred metabolite."
] |
[
"If I was to attach a dynamo to the exhaust pipe of my car, how much electricity in theory would it generate?"
] | [
false
] | Lets say I have an average diesel engine car (if you need figures just pick any old car as example) and I was going 70mph how much electricity would I generate if I put some sort of dynamo on the back of the exhaust pipe? I'm just curious as to why no one has specifically made use of the energy that is being wasted by ... | [
"Yup. First law of thermodynamics - there ain't no such thing as a free lunch. Any power generated from that dynamo would be coming from the engine anyway, so you're better off not having it. You can't consider the exhaust to be an unlimited source of moving air - you are combusting the engine to create that air, a... | [
"I imagine that the backpressure put on the engine would diminish the engine's power more than the dynamo would produce?"
] | [
"TANSTAAFL, unless you could harness the waste heat to run a stirling engine... but that was not his question."
] |
[
"Of all the nuclear tests completed on American soil, in the Nevada desert, what were the effects on citizens living nearby and why have we not experienced a fallout type scenario with so many tests making the entire region uninhabitable?"
] | [
false
] | null | [
"Difference between a blast delivered by a device, and a meltdown of a nuclear pile (far more material than a bomb, slower release)."
] | [
"Pardon my ignorance, but how come people can live in those places after that, but Chernobyl is uninhabitable?"
] | [
"Pardon my ignorance, but how come people can live in those places after that, but Chernobyl is uninhabitable?"
] |
[
"If you were to put a pipe down the the deepest part of the ocean that reached up to the atmosphere, would the water move up it due to the pressure and if so depending on the radius of the pipe how high could it go?"
] | [
false
] | [deleted] | [
"The pressure in the ocean depths is caused by the weight of the water above it. If you put an empty pipe down to the bottom of the ocean and opened it, water would be forced up the pipe until the weight of the water in the pipe balanced the force from the pressure at the bottom of the pipe. Not coincidentally, the... | [
"You mean if the pipe were evacuated (made to be a vacuum) and if it were to go all the way up to space? Yes -- it actually would go a bit higher. About 30 feet higher. This is another take on the question: \"how long can you make a straw before it stops working?\"",
"The limit for any straw is about 30 feet,... | [
"Would the lack of pressure in the upper atmosphere/space suck it up higher?"
] |
[
"Want to build a real BMO (from Adventure Time) and want to know his actual size (x-post from AskReddit)"
] | [
false
] | [deleted] | [
"Thats not really what this sub is for guy. Can't you do this yourself anyways?"
] | [
"BMO has no size, animation models exist solely through comparison to each other. You're asking for a guestimation based on screenshots to a show with a surreal bent that doesn't even have consistent sizing anyways. Your try is just as good.. as for the sub issue, AskScience is for ",
" not ",
" but I wouldn't ... | [
"Why not? Is this not science related? I'm trying to engineer a BMO and I suck big time at math, so I thought lets ask the science guys."
] |
[
"[Light] Why is the angle of incidence the same as the angle of reflection? Why is it not twice, or half?"
] | [
false
] | I know this is quite abstract, and maybe it's impossible to know, but is there some reason it had to be that way? | [
"There's a derivation ",
"here",
". Both the law of reflection and Snell's law of refraction come from considering the boundary conditions on the electric field across the interface of two materials."
] | [
"Fermats principle",
"https://en.wikipedia.org/wiki/Fermat%27s_principle",
"Essentially shows that light will travel the path that occupies the least time. For 2 points the shortest distance will be a straight line. In the case of a reflecting surface, that results in having the angle of incidence equal to th... | [
"This is unfortunately an incomplete explanation, as it is entirely conceivable that (a) if the total momentum of the EM field is to be conserved, it is only the sum total of the incident, reflected, ",
" refracted waves which must be zero, giving you an extra degree of freedom to make your angle of reflection wh... |
[
"How are instincts stored in the brain? The same as memories?"
] | [
false
] | Instincts, such as an infant sucking on a nipple, must have some sort of mechanism. Where is it location, and what does it look like? | [
"We know much of what we consider \"instincts\" in neonate creatures in nature are stored in DNA. The process of DNA->expression of a trait/protein is well known, however how this process results in the behaviors of instincts, we have pretty much no clue. In fact, it may be better to not think of instincts as a dir... | [
"Two of the best examples I know:",
"http://www.nature.com/nature/journal/v493/n7432/full/nature11816.html",
"http://www.pnas.org/content/89/13/5981.short"
] | [
"Thank you, I was having a hard time finding anything."
] |
[
"Water solubility of caffeine, or, if I use a tea bag a second time has it become mostly decaffeinated?"
] | [
false
] | So I find that I can get two cups of tea out of a tea bag (which I'm sure infuriates tea purists). I like to avoid caffeine near bead time, so I was wondering whether a second steeping of a tea bag would produce a mostly decaffeinated tea. So what do you think? Does most of the caffeine dissolve on the first steep? Wha... | [
"I do the same thing, so I got curious about the exact numbers. Fortunately some researchers actually looked at this question systematically in ",
"this paper",
". The key result is summarized in ",
"this table",
", where they looked at the fraction of caffeine extracted after different types of tea were st... | [
"It should also be noted that the solubility of caffeine massively increases with temperature. That is to say that, in hot water, the majority of caffeine will dissolve pretty quickly. "
] | [
"Which works out, since black leaf tea, which contains the most caffeine is properly steeped at near boiling. While white leaf, which has little caffeine is best steeped closer to 170 f. "
] |
[
"How do nutritionists know that something has zero calories?"
] | [
false
] | I know that a single calorie is the energy it takes to raise one CC of water one degree Celsius - (right?) - But how is it determined that something like sucralose has no calories? EDIT: I meant sucralose. | [
"There is an instrument called a bomb calorimeter. Its just a relatively closed system that is filled with pure oxygen so that you can burn stuff. After you are done burning stuff you see how much energy went into raising the temperature of the water around the sample. "
] | [
"Wouldn't really work for something like sucralose. Sucralose is still an organic molecule and can burn and give positive calories in a bomb calorimeter, your body just doesn't have the capability of metabolizing it at all."
] | [
"Sucrose (table sugar) has a pretty big caloric value. Are you sure you didn't mean sucralose? Like bitter_twin_farmer said, caloric value can be found with bomb calorimetry. But, you also have to take into account whether you body has the machinery to digest something like sucralose to get any valuable energy o... |
[
"Were fruits smaller in the past?"
] | [
false
] | I spent today watching some older films from over seventy years ago from the forties and before. When they show fruit trees or someone picking fruit the apples, oranges, lemons look so tiny compared to what I'm used to. Is this screen optical illusions or were the fruits smaller seventy years ago compared to now? If so... | [
"there are a lot of things that science claims that have proven are in fact just theories and evolution is one of them.",
"You don't understand what a scientific theory is."
] | [
"There are two explanations to this;",
"1 - Varieties of fruit vary hugely and the cinematographers may have chosen to film smaller varieties for various aesthetic reasons.",
"2 - We have been selectively breeding fruits bigger for thousands of years to improve the yield of crop from a single plant. This has ha... | [
"Theory is something that science \"thinks\" happened and then writes in history/gography books as proven facts and to be honest im sick of this shit."
] |
[
"Could antimatter destroy a black hole?"
] | [
false
] | Since black holes are made of matter, could a large enough quantity of antimatter sent into a black hole destroy, or at least destabilize, a black hole? | [
"No. Antimatter still has positive mass it just has the opposite charge as it's normal matter partner. So antimatter that falls into a black hole will increase the total mass of the system. ",
"So why won't the matter-antimatter annihilation cause the mass inside the black hole to disappear? First to assume that ... | [
"To build on this, all of the mass-energy from the particle annihilation is still contained in the black hole and will not escape until it is emitted via Hawking radiation."
] | [
"No. Whether a black hole gets its mass from matter or antimatter makes absolutely no difference; both increase the mass of a black hole. "
] |
[
"Question regarding Wasps/stinging insects: How did the biology of a stinging insect evolve correctly to produce a formula that would effectively hurt or \"sting\" its victim?"
] | [
false
] | null | [
"I'm not the best person to answer this but I googled the evolution of bee stings and found this. Perhaps someone else could run with this or elaborate on it: ",
"\"The bee's stinger evolved originally for inter-bee combat between members of different hives, and the barbs evolved later as an anti-mammal defense... | [
"I'm not sure it makes sense to give evolution purpose like that (the quotes). Features don't evolve 'for' anything."
] | [
"What you are describing is the idea of the Red Queen hypothesis, and to my knowledge, is still how many people think of things like this. No matter how far \"ahead\" a species get, it's always being \"one upped\" by another species."
] |
[
"What substances can reflect other parts of the electromagnetic spectrum?"
] | [
false
] | I know a mirror will reflect most of the visible spectrum; as well as some heat in the infrared. I guess what I want to know is do different types of substance reflect different parts of the electromagnetic spectrum? | [
"Yes, the frequency-dependence of a material's reflectivity is typically quite complicated. ",
" reflect some portions of the electromagnetic spectrum to some extent, and transmit or absorb more in other portions. For instance, take a look at this ",
"reflectance spectrum of grass",
", soil, and water. Even a... | [
"Metals are generally good reflectors of EM radiation, at least up to X-ray scales. The reason is that they conduct, so when the radiation hits the metal, charge moves around in the metal to counteract whatever forces the wave is applying. That motion of charge then itself creates a wave of identical frequency to t... | [
"Thanks for your great answer. My question came about thinking of home insulation and foil barriers. As long as they don't touch other surfaces (conduction) when built into a wall they behave (in the dark) as a reflector keeping heat in the house. I started to wonder if something actually needs to appear \"shinny\"... |
[
"Why do atoms \"want\" to get full outer electron shells when bonding?"
] | [
false
] | A hydrogen atom on its own is stable, and has no overall charge. The same goes for oxygen. So why would they bond to form water, which has the exact same charge? Also what causes chemical bonds to have specific angles? | [
"Good question! Understanding this behaviour requires that you first understand that a reaction can be considered as a number of individual processes. When you combine chlorine and sodium to make table salt, the sodium atom loses an electron, the chlorine atom gains one and the resultant ions bond due to their char... | [
"I remember one of my lecturers telling me there was nothing special about a full shell, and that it is just where energy minima tend to be.",
"One of the reasons for this is shielding of the nuclear charge:\n",
"http://en.m.wikipedia.org/wiki/Effective_nuclear_charge",
"\nElectrons in inner shells shield the... | [
"So, is this why some reactions cause exothermic reactions, and some cause endothermic reactions?"
] |
[
"Why and how is Carbon such a good element for forming life and are there other-element based lifeforms possible?"
] | [
false
] | I read an article in which Stephen Hawking said that Carbon has the richest chemistry possible. I have not studied chemistry beyond high school, and I sometimes think that ok, there should be other elements that are in the same "column" in the periodic table, and should behave similarly. Are we to believe that if we f... | [
"Short answer: Because there is more carbon that any other 4 covalent bond element like Si Ga Sn Lb,and it forms a large range of molecules ",
"long answer\nCarbon is a very good element for life as it can have up to 4 covalent bonds.",
"This means that carbon can form a range crazy range of molecules due to t... | [
"Silicon also works, and is key in certain animals, like echinoderms, but silicon has the disadvantage that it forms crystal matrices instead of carbon chains. Great for laying a starfish skeleton but less useful in other metabolic processes. "
] | [
"on this planet with these conditions, yes. other planets, or even clouds of gas in space, have different conditions which might be ideal for silicon based life. we just dont know yet"
] |
[
"What would happen if we placed an object orbiting around a black hole such that in the closest point of the orbit, the object is inside the Schwaszschild radius?"
] | [
false
] | Assume that we initially place the object outside of that radius, but as it follows an elliptic orbit, it enters that radius while orbiting. Would it outspeed light? Would it be able to not fall inside the black hole? | [
"If something enters the Schwarzschild radius, it's not coming back out again."
] | [
"There are no elliptical orbits with that description in a Schwarzschild geometry."
] | [
"There's nothing special about an orbit that would make it escape a black hole. Putting something on an orbit entails giving it the appropriately orbital velocity to match the trajectory you want, which in this case, would be insufficient to keep it outside the Schwarzschild radius.",
"EDIT: It's a depressing com... |
[
"Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"How much heat does the earth receive from stars other than the sun? Say, as a percentage of the sun's heat."
] | [
"Exo planets = planets not a part of the solar system.",
"Rogue planets = planets not orbiting ",
" star",
"Rouge planets = planets that are red"
] | [
"What are the most likely candidates for dark matter at the moment? "
] |
[
"Wildlife biologists: Prospects of an anole in northern Virginia?"
] | [
false
] | So, my 19- and 21-year old roommates adopted a ringneck snake they found in the wild. Tonight they came home with an anole that is bigger in circumference than the snake and has been sitting at the top of the aquarium all night. It is raining now pretty badly but if it stops I am thinking about taking the anole outside... | [
"Please do not release animals to the wild. Ever. For any reason. Animals from the pet trade can harbor disease that can threaten entire populations. If they do make it they may harbor genetic differences that can negatively affect local populations. As you suggested, the individual will also be likely not to make ... | [
"If you get another snake and then teach both snakes how to golf, you could get anole in one."
] | [
"Also, ",
" take animals out of the wild to try and take care of them. Its a bad bad idea."
] |
[
"Is \"anti-gravity\" physically possible? What about artificial gravity in space?"
] | [
false
] | null | [
"It is worth noting to your last point that according to the ",
"Equivalence Principle",
" acceleration can be indistinguishable from gravity."
] | [
"The gravitational force as we know it acts in one way; as a force directing towards a mass. To oppose this we would require negative mass. Which as far as we know does not exist. To add to that statement, anti-matter ",
" to have positive mass according to CERN, sorry I don't have a link but they did experimen... | [
"As far as we can tell, the only thing that creates gravity is tons and tons of pure mass. Furthermore, it appears that all gravitational forces are purely attractive. So anti-gravity is not physically possible by any means."
] |
[
"What is at the centre of the moon/other planets in our solar system?"
] | [
false
] | Is the moon just a big rock? Do planets like Mars have molten iron at their core like Earth? What is at the centre of gas giants like Saturn, does the pressure cause the gases to react in any interesting ways? | [
"Most bodies orbiting the Sun have cores, for the most part they are made out of the densest materials found on that body (usually iron or silicates). For gas giants it gets a bit wired since they have no clear surface. They just increase in pressure gradually as you go deeper. For example on Jupiter at one point y... | [
"You say Jupiter probably has a small dense molten core, but can you define small? Are we talking the size of a few miles wide, or more along the lines of a few Earths? I would think that Jupiter caught a lot of debris, from not only asteroids, but failed planets and moons over the last 4.5 billion years or so. Eve... | [
"I expect the inner core to be between the size of Europa to the size of the Earth."
] |
[
"If the divergence of the magnetic field is zero, does that mean it always exists but its B is 0 sometimes?"
] | [
false
] | In E&M we went over the divergence of a magnetic field being zero while it has a curl. This brings me to my question: if the divergence of the magnetic field is zero, does this mean that there will always exist a magnetic field around a charged particle whose strength is zero when it is stationary? This seems to make s... | [
"Divergence means this: If you draw any surface, is there more outward flux of the field than inward through the surface? For any electrically charged object, Gauss's law says that -- regardless of the shape of any surface you would draw around it -- the net flux of that field (out minus in) is proportional to that... | [
"The assumption is that if there were a magnetic monopole, then there would a law equivalent to Gauss' law, where the divergence is proportional to the \"magnetic charge\" of that monopole. So in a sense, the zero-divergence law for magnetism is saying that, as far as anyone can tell, there is no magnetic monopole.... | [
"The divergence is basically saying what happens to the field as you follow it. Because there are no magnetic charges, as you follow magnetic field lines they stay constant, so the divergence is zero. The curl tells you what happens as you move perpendicular to the field.",
"An electric charge monopole (which I t... |
[
"AskScience AMA Series: We are statisticians in cancer research, sports analytics, data journalism, and more, here to answer your questions about how statistics opens doors for exciting careers. Ask us anything!"
] | [
false
] | Statistics isn't what you think it is! With a career in statistics, the science of learning from data, you can change the world, have fun, satisfy curiosity and make a good salary. Demand for statisticians is on the rise, and careers in statistics are consistently on best jobs lists. Best of all, statistics applies to ... | [
"Are any of you at all worried about the huge output of data science \"boot camps\"?",
"It seems to me that an exceeding number of people come out \"knowing\" how to do statistics, meaning they can use code to test data but without having a deeper understanding of the limitations of using statistical approaches t... | [
"what are some unexpected/unconventional jobs you can get as a statistician? What stat related uni courses would you recommend that are most useful even for other majors?"
] | [
"excellent question. I have found that most students (especially those who are taking it bc it's required) have very very low expectations (due to fear or bad rep that the class gets) so the silver lining to this is that you have no where to go but up!!",
"I have found that spending the first two weeks going thr... |
[
"Do trees create less oxygen in the winter after their leaves fall off?"
] | [
false
] | null | [
"Generally, yes. Photosynthesis, of which oxygen is a byproduct, happens in the chloroplasts. ",
"The vast majority of the chloroplasts are in the leaves, so a deciduous trees ability to produce oxygen is drastically reduced after shedding its leaves."
] | [
"Here ya go.\n",
"https://www.jpl.nasa.gov/videos/watching-earth-breathe-the-seasonal-vegetation-cycle-and-carbon-dioxide"
] | [
"That said, I'll mention it just in case, that's not an issue at all if you were thinking of the \"stock\" of available oxygen.",
"A few months after that Avengers movie with the Thanos snap, there was this interesting reddit discussion, in which \"what would happen if that snap also wiped half of the oxygen-prod... |
[
"What is the mechanism for how alcohol affects your body?"
] | [
false
] | So I just did a quick google search to find the biochemistry behind the ingestion of alcohol, but my search has yielded diddily-squat. I know most recreational alcohol has many species of alcohol but the highest concentration of ethanol. My main question: What happens to ethanol once it enters the body and begins to be... | [
"Your main question about alcohol metabolism is fairly well understood, it is oxidized to acetaldeyde then to acetic acid and excreted. The question about its neurological effects is actually a very good question because its on the cutting edge of research and really isn't well understood. ",
"Old textbooks, as w... | [
"No problem, I really enjoy communicating science; its a big interest of mine. GABA channels are only one of the channels controlling chloride entry, sorry, I should have been a bit more clear on this point. Chlorine is usually at higher concentration outside of the cell, when it is allowed to flow in, the inside o... | [
"Awesome! Great answer!",
"So the GABA channels control the flux of chlorine into and out of a cell? What kind of cells are talking about? Are we talking about neurons in the brain? So what exactly does GABA inhibit? The conformational change of the GABA ion channels to close, and not allowing chloride to flow? "... |
[
"Could someone please help me identify this mineral for my son? He is planning to take it to school for show and tell."
] | [
false
] | null | [
"It looks like ",
"bismuth",
". "
] | [
"Technically, ",
" is the heaviest non-radioactive element; Bismuth is radioactive. However, it's so ridiculously stable that it's completely safe.",
"The half-life of the longest lived (and most commonly found) isotope is around 2x10",
" years, which is roughly 1.4 billion times the current age of the univer... | [
"HOLY SHIT ITS BISMUTH!"
] |
[
"[Physics] Why do EM waves that reflect off a surface at very small angles polarize parallel to the surface?"
] | [
false
] | Preferebly with a nice metaphor to help a friend of mine understand | [
"When light encounters a boundary between two media with different indices of refraction, some will be refracted and some will be reflected. This is modeled by the Fresnel equations (which, I think gives the real scientific answer to your question ",
"https://en.wikipedia.org/wiki/Fresnel_equations",
")",
"I ... | [
"Ohhhhhhhhhhh, I read the question completely wrong. ",
"/u/tbu720",
" gave a better response and I could have given a better one than I did if I had read it correctly. I read it as the wave reflects in almost the same angle it was incident in."
] | [
"The situation is when light hits a surface nearly parallel to the surface, far from the normal. There's a critical angle below which the reflected light will be polarized parallel to the surface. I forgot the name of the effect however."
] |
[
"Do blind people have the same circadian rhythm?"
] | [
false
] | [deleted] | [
"I cannot speak to it in detail but I know some people who are blind have trouble with their sleep wake cycle. Its called non 24",
"https://en.m.wikipedia.org/wiki/Non-24-hour_sleep%E2%80%93wake_disorder"
] | [
"I have answered this ",
"before",
", so I'll quote it here. ",
"[It's] a little complicated. First, we'll assume you mean totally blind, as even a little bit of sight (remember that legal blindness includes a range of low-acuity vision) will at least be able to tell light from dark. As long as the retina is ... | [
"this question interested me so I did a little research.. found this: ",
"The following is an abstract of a paper, \"Circadian rhythm abnormalities in totally blind people: incidence and clinical significance\", by Sack, R.L., Lewy, A.J., Keith, LD, and Nakagawa, H, 1992.",
"\"When people are completely isolate... |
[
"What makes hydrocarbons so efficient at storing energy?"
] | [
false
] | null | [
"They burn to carbon dioxide and water, and those reactions release a good deal of energy. There are plenty of other chemical structures that release energy in their reactions, but many of these are dangerously reactive (explosives, for example).",
"Carbon-carbon bonds, though, are stable in long chains (unlike m... | [
"It's more the bonds that are being formed. Carbon dioxide and water, energetically, are quite a bit downhill from say, octane. Forming the two C=O double bonds is especially favorable, and the other thing that helps is that it's a gas. That means more entropy in the system when the reaction goes to products, and b... | [
"Forgive me if this is getting too specific, but what exactly about the bonds in hydrocarbons make them release so much energy when broken? "
] |
[
"What plants have gone extinct along with animals over the years?"
] | [
false
] | So, I was reading about and I was wondering about quotes such as "17% of all families, 50% of all genera[6] and 75% of all species became extinct". Initially I assumed that only applied to dinosaurs and other types of animals and insects. However, did it also apply to plants, specifically fruits and vegetables? Do we h... | [
"Well, I'm not a scientist, but Wikipedia's ",
"entry",
" on paleobotany seems fairly thorough, and it links to a list of ",
"extinct plants",
"."
] | [
"That's awesome to know, and I promise I'll check those links when I'm not somewhere that blocks them."
] | [
"That's awesome to know, and I promise I'll check those links when I'm not somewhere that blocks them."
] |
[
"Blood in stool sample, which kind of doctor should I go see?"
] | [
false
] | null | [
"Hi, we are sorry to hear about your symptoms. We don’t provide medical advice on this subreddit, all we can do is recommend you see a medical professional. If you have a general practitioner, that would probably be the most affordable option. The specialist who would deal with this is a gastroenterologist. ",
"H... | [
"You are amazing, thanks for your help"
] | [
"Thanks, I really appreciate the info"
] |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"What are some possible experiments to support or refute the ",
"OrchOR",
" theory? I'm trying to think of something that shows any sort of information transfer along microtubules, and perhaps relating it to phosphorylation states of the tubulin and associated proteins. ",
"This paper",
" seems like a good ... | [
"I think you may be confusing eye damage with evolution. While I'm not sure if constantly wearing coloured lenses would even cause a change, it's the ",
"intensity",
" of the light that causes damage, not the colour itself. Causes of colourblindness are genetic, or due to drugs/physical damage. ",
"On top of ... | [
"Neuroscientists: what scanning technologies are on the horizon? Is there soon to be a major increase in scanning resolution so that we can learn more about cognition?"
] |
[
"How does this occur? (Gif in text below). I know it's a prominence/flare but why is it spinning and circular?"
] | [
false
] | It appears to be almost the same size as earth. It appears to be spinning very rapidly and also appears to be a perfect globe. Why's it round? Where's the magnetic effects? How does it spin? It appears to be outside the corona, heat much? | [
"It looks a heck of a lot like a closed loop of magnetic field lines with some hot plasma trapped on it. The plasma will follow the field lines in a circle, and accelerating (circular motion) a charged particle (plasma) in a magnetic field can cause an emission of light - ",
"cyclotron radiation",
". These sort... | [
"I'm trying to find a good graphic to illustrate it but I can't find any really good single ones so I'll link a couple of different ones. The basic idea is that, as different parts of the Sun rotate at different speeds (it's not a solid surface), the lines connecting those different parts get twisted up and wrappe... | [
"Thanks, I'm still not getting how it actually forms the loop. Especially so far from the surface. There doesn't appear to be any reason. I understand the plasma can form a closed loop, although I've never seen it until now"
] |
[
"How can an alt-azimuth telescope align itself with only one star?"
] | [
false
] | I don't know much about astronomy, so I'll do my best to explain my question better. I own a Celestron telescope (Nexstar 90GT) that has a computerized panel to help find stars and track them as they move across the sky. The mount that the telescope is on can swivel in two directions; altitude and azimuth. When I pow... | [
"The telescope has a mathematical model of the Earth's rotation and orbit built in. Based on the time and date, the telescope knows the position and orientation of the Earth with respect to all the stars in the sky. Now all that's left to do is to find the orientation of the telescope with respect to the Earth. ... | [
"I see some ambiguity left. We know the time, so we know the point of Earth directly underneath the star. The telescope measures the star to be 70 degrees above the horizon. That narrows down the telescope position to a ring at the surface, and the orientation is a similar ring. If you want to go to a different sta... | [
"Then how does it work? Unless it has GPS or a compass, one of them would remove the ambiguity."
] |
[
"Do wings on a spacecraft do anything while in space?"
] | [
false
] | null | [
"Short answer: ",
"Slightly longer answer: Wings do nothing at all significant while in high orbit. In a low orbit yes, you can get tiny amounts of lift as demonstrated by the ",
"GOCE",
" satellite but you're actually still in the (extreme upper) atmosphere at the 160km altitude GOCE was used at. It also did... | [
"If you mount your reaction control system on your wing tips you may benefit from a more efficient production of torque, but I am not sure on the specifics."
] | [
"This is correct, and you can think of it like a lever. The further you are from the center of mass, the more efficient it is. Think of putting a reaction nozzle in the center of mass. The spacecraft won't rotate if you fire it (it will accelerate slightly in the opposite direction though--a translational maneuver)... |
[
"Are there mosquitos on atolls (islets, skerries, and cays) in the middle of the ocean? If so how do they even reproduce"
] | [
false
] | Mosquitos have to have standing fresh water right? | [
"True and fair, and a lot more detailed.",
"There are probably more places than just Antarctica where there's no suitable habitat or did source, or to which to mosquitoes haven't made it yet, or survived for long of they have made it there.",
"Mostly, it rains on these islands, so at least briefly there are fre... | [
"There is fresh water on those locations. It only takes two of the right kind of mosquito in the right place and time, and mood, to reproduce.",
"Yes, there are mosquitoes there.",
"Everywhere, I believe, except Antarctica. I’ve been to islands in the middle of the Pacific and have seen mosquitoes, but not to A... | [
"almost correct. there are islands with no mosquitoes other than the continent of Antartica. Iceland is a good example. With regards to non-human-colonized islands probably the majority of them have no mosquitoes (dispersal is a rare event).\nAlso note that a lot of mosquito species dont need “fresh water” per se b... |
[
"How does sharpness work? If I had a blade that was impossibly sharp, could it cut through rocks like they were butter?"
] | [
false
] | Also, can sharpness be so sharp that the weight of the blade is enough to cut? ie A knife cutting through a table because its weight is enough force applied to cut. | [
"I see people giving you great theoretical answers with great science behind them, so I won't belabor the technical point they've already brought up and I'll move straight into the practical meat of the answer.",
"Short answer, no. This is because we don't have a material to make knives out of that would stand up... | [
"...except that the force/unit area also applies to the knife edge, which needs to be strong enough (and tough enough, which is a different issue) to withstand the applied stress."
] | [
"I can't answer your main question, but I can answer your second question. Yes, a blade can be sharp enough that the weight of the blade alone is enough to cut things.",
"\"Cutting\" is applying force over area. If you have a barrel sitting on the ground, the weight of the barrel times the acceleration (gravity... |
[
"How did omicron get *50*mutations? Would this happen in one host or would 1 or 2 mutations happen in one person and that transmitted just a bit better than delta?"
] | [
false
] | In other words….you’ve got the delta variant, which I assume is the variant omicron has fifty different mutations from? (Or is it 50 compared to the original?) Anyhow, person A has Delta. Does delta gain 50 mutations in person A, and so it transmits more and got to person B? Or does it develop 1-2 mutations reproducing... | [
"A nit: omicron didn’t descend from delta, it’s a separate strain that developed, but wasn’t widely present in populations where testing occurs, about a year ago.",
"https://www.npr.org/sections/goatsandsoda/2021/12/01/1055803031/the-mystery-of-where-omicron-came-from-and-why-it-matters",
"I’m pretty sure the 5... | [
"The latest hypothesis is it came from mice.. lots of unvaccinated animal reservoirs out there just brewing up variants.. White tail deer population is rife with corona virus ( same one we have)",
"Deer have Covid ",
"Mice have Covid ",
"all kinds of animals are Covid reservoirs ",
"Especially when you ‘hum... | [
"A mutation is simply a mistake. When the DNA is copied, a mistake is made in that copy. That's all a mutation is. The copy mechanism for DNA is VERY good but you also can get 10,000 copies of a virus from a single cell. So, while mutations are on the rarer side (once every 10,000-10,000,000 copies), the number... |
[
"What mammal is least related to all other mammals?"
] | [
false
] | That might have been a bad way of phrasing the question but basically you know how all animals have a closest living relative and that broader group will be closely related to a similar broader group so on and so forth but what mammal or even group of mammals is the most distant from all other living groups | [
"It's a little unclear exactly what you're asking, but the earliest branching event in the mammal tree of life is between monotremes (platypuses and echidnas) and all other mammals. This split occurred somewhere around 200 million years ago. However, the separation between platypuses and echidnas themselves is mu... | [
"This is the current best guess based on phylogenetic data",
"So the first branching separates the monotremes from the rest. Monotremes include echidnas and platypuses. They have fur and largely resemble other animals, but still lay eggs, a carryover from our more repitlian past.",
"Then the next branching sepa... | [
"You might want to add this ",
"phylogeny which is easier to read"
] |
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