title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Is it possible to reverse the reaction in a glow stick so you could make one that was reusable?"
] | [
false
] | null | [
"In principle, sure. There's no reason a reversible chemiluminescent system can't be developed. However, I don't know of any that lend themselves to easy regeneration after the light-producing reaction has occurred."
] | [
"The reaction also releases energy in then form of light, so if you were able to reverse the reaction you would have to impart energy back into the system. "
] | [
"the reaction inside a glow stick is initiated by breaking a glass vial inside the glow stick, mixing the chemical inside with the vial with the chemical that it is submerged it. Once the vial is broken, the chemicals can't be separated."
] |
[
"Is there a smallest unit of time?"
] | [
false
] | I was thinking about time, and how we are affected by things around us like gravity, and how everything happens in "realtime" Is there a shortest period of time that something (anything) can happen? Edit: I understand Plankt time now. But am still very curious if there is a "smaller" period of time that something can happen in. That a force (like gravity) can affect something. Or if it is all truly in real time. | [
"No - not as far as we know.",
"The ",
"Planck time",
" is often mentioned in this context - that is roughly the scale at which our understanding of physics breaks down. We aren't sure what, if anything, happens during time intervals that short. But there is no consensus on whether it is the shortest time i... | [
"Actually, there's no reason to believe that it is the shortest time interval possible. So there is a consensus, it's just ",
" the existence of the Planck time being the shortest possible time.",
"However, physicists are aware of the possibility that a quantum theory of gravity could include the existence of a... | [
"We talk about smaller time-scales all the time, since all of established physics is working with time being continuous and differentiable."
] |
[
"When astrophysicists say that a planet is the same size as Earth, do they mean in terms of mass or in terms of diameter?"
] | [
false
] | null | [
"Well, you probably won't catch an astrophysicist using a term as vague as \"size,\" particularly not in a research paper - scientists will be specific when talking about radius, mass etc. But when these things get reported out and covered outside the primary literature, the word \"size\" can indeed mean different ... | [
"Yeah, I don't see an astrophysicist saying \"same size.\" ",
"But I think OP is probably thinking more along the lines of popular science articles that have headlines like \"Astrophysicists discover planets with the same size of Earth.\"",
"Without context, what would that mean? To me, just based on the head... | [
"Whichever gives them the most sensational press coverage :P.",
"eg: ",
"Kepler-22b",
" was discussed as being 'twice the size of Earth' which is true in terms of radius, but probably has a mass and volume more than 10 times that of Earth.",
"eg: ",
"Gliese 581g",
" has also been expressed to be 'three ... |
[
"How is it that pathogens with very high mortality rate don't go extinct simply by the fact that they kill their victims before they can spread it to others?"
] | [
false
] | null | [
"If it still exists it means it was able to find new hosts. Some are very contagious and able to contaminate others before the death, others can spread from cadavers, others can survive in the environment (air, water, ground...) and many have animal hosts. ",
"Rabies have animal hosts, for example. Tetanus surviv... | [
"Tetanus is an amazing example. Clostridia tetani (tetanus) and it’s relatives Clostridia botulinum (botulism) and Clostridia difficile (C-dif) among others, are a genus of obligate anaerobic, endospore forming bacteria.",
"These bacteria evolved to live in the absence of oxygen and exposure to oxygen is actually... | [
"Here's a paper on how ebola behaves",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7061886/",
"\"One-health approach is likely to provide a good understanding of the drivers of spillover events from forest-dwelling fauna to forest interfacing humans, which will enable Ebola prevention and control at source. T... |
[
"What determines a sapphire color?"
] | [
false
] | null | [
"Sapphire is made up of a lattice of aluminum atoms and oxygen atoms, but it's really hard to get a pure lattice, and sometimes other metal atoms get mixed in. All these metals interact with light in different ways, and the result is a variety of colors.",
"If there's chromium, then the stone will appear red.",
... | [
"It would be colorless and transparent."
] | [
"What would happen if it was pure lattice? "
] |
[
"Why do NSAIDS antagonize THC effects?"
] | [
false
] | By personal experience, anecdotical evidence and I know that Non steroidal anti inflammatory drugs like aspirin and iboprufen antagonize THC effects. In other words they sober you up very fast. Can anyone here explain me why they do it? Thanks, guys. | [
"I'm going to try and make this is as coherent as possible...but it's tricky. THC does its thing by binding to a cannabinoid receptor (CB1), which is where most of the high comes from. ",
"The reason why you have cannabinoid receptors in the first place is that you have an endogenous cannabinoid system, with ana... | [
"Thank you so very much for this great answer. It was puzzling for me to watch someone uncomfortably high take a couple advils and be as good as new in a few minutes. "
] | [
"No prob! I'm curious though if this happens more with people who smoke very regularly, or have you noticed this effect even after not smoking for awhile?"
] |
[
"Where does breastmilk come from and where does it come out of on the nipple?"
] | [
false
] | null | [
"Breast tissue contains specialized cells calls lactocytes that take in nutrients from the blood, and secrete milk into a spongy network of tubules (very similar in structure to your lungs' network of bronchioles and alveoli, but in reverse) that store and transport milk. These tubules all meet up at the nipple, v... | [
"Thanks, I was really wondering and my buddies had no clues so I came to the pros and they delivered."
] | [
"Is this system just underdeveloped in males, or does it not exist at all?"
] |
[
"Without an alarm or other external source for waking us up, what prevents our brains from being asleep forever?"
] | [
false
] | null | [
"You have a really complicated internal clock called your circadian rythym that helps you know when to sleep and wake up. In short you have neurons that run in a loop, activating and deactivating themselves (a bit like a Redstone clock actually if you play minecraft), and similar proteins too that inhibit their own... | [
"It's actually called CLOCK (I know, biologists are great at naming things. Stands for Circadian Locomotor Output Cycles Kaput) and it can bind to its own section of the DNA and prevent it from being transcribed. So as more of it is made, the higher the chance it is bound more often and less of it is produced, then... | [
"What are these self-inhibiting proteins and how does this work?"
] |
[
"AskScience AMA Series: I'm Kevin Esvelt, head of the Sculpting Evolution group at the MIT Media Lab and an inventor of CRISPR gene drive - AMA!"
] | [
false
] | Hi, my name's Kevin Esvelt and I'm a scientist working on molecular, evolutionary, and ecological engineering. I played a very minor role in developing CRISPR genome editing and was evidently the first to realize it could be used to build gene drive systems capable of engineering populations of wild organisms. If you haven't read about gene drive - and even if you have - I highly recommend reading this by Dylan Matthews of Vox. Relatedly, I'm a strong advocate of more open science, beginning with as a small and high-profile field trial of pre-registration in tech development. Finally, we in try to carefully consider our and publicly . We'll be on at 2pm eastern (19 UT) - AMA! EDIT: Last Week Tonight with John Oliver did a about this just last night! EDIT #2: Our guest needs to take a break, but will be back later tonight to answer many more questions. | [
"What are your thoughts on the movement to make all scientific publications open to the general public? Would this be useful or does a lack of contextual knowledge make it better to force inclusion of experts/scientists?",
"What should a scientists role become if all publications were made freely available? "
] | [
"Ok. You're the person to answer!",
"When we modify a gene and insert it into a multicellular host, how does that gene propagate? Since there are a vast number of non-modified cells why don't their descendants (as it were) overwhelm the cells with the new gene through sheer weight of numbers?",
"Or in other wor... | [
"First, I’m pasting many of these from a Google Doc, which is is why these may go up quickly. ",
"In general I think it’s better if research is open rather than closed. Especially for publicly supported studies, there is no obvious reason to restrict the results to affiliates of dues-paying organizations rather t... |
[
"How much time will it take for the CMBR to cool to radiowave frequencies? Won't this have an effect on free electron spins?"
] | [
false
] | If free electron spin is affected by radiowaves, then won't they be affected by what is at some point a cosmic radiowave background radiation? | [
"There isn't really that sharp of a line microwaves and radio waves - the EM spectrum is a continuum. ",
"CMB peaks at 160 GHz, RF generally speaking extends from 300 GHz down to a few kHz. In this sense, the CMB is already 'radio waves.'",
"But maybe if you want to call anything above 3 GHz a microwave, then y... | [
"The energy of an electron spin transition depends on the magnetic field it is in. Most chemical reactions involving unpaired electrons won't be affected much even if there is a strong radio background at the right frequency (for an unpaired electron in Earth's field).",
"Many electron transfer reactions that in... | [
"The CMB is incredibly faint, it's not going to effect biology. Compared to the radiation from the sun, or the black body spectrum of anything on the earth's surface, the CMB is a tiny bit of noise. "
] |
[
"Can we actually see electrons, or do we just see the air being heated up when we see electricity?"
] | [
false
] | null | [
"Whenever you see something, what is happening is that the object is emitting a photon that hits your eye. So if by \"seeing\" the electrons you mean seeing the photons emitted by electrons then yes we do see electrons.",
"However, its worth noting that basically everything you see in your daily life is from phot... | [
"Sparks are electrical plasma. If we lived in a Neon gas atmosphere, sparks would be red-orange. The usual violet color of an electric spark is produced by nitrogen and oxygen line-emission.",
"Interesting trivia: a vast number of movable electrons, such as the electron-sea of metals, is an extremely good refl... | [
"do we just see the air being heated up when we see electricity?",
"I think here you're referring to the plasma arcs created by lightning, a spark, or a tesla coil. In that case what you're seeing is the visible glow of air in its superheated plasma state, where the molecules that make up the air are stripped of... |
[
"A Brotherly Debate 1: How do I explain evolution to my stubborn brother."
] | [
false
] | null | [
"http://www.talkorigins.org/faqs/evolution-fact.html",
"is a good source for highlighting the difference between facts and theories if he is hung up on that definition. If he doesn't understand the mechanism of gradual change, I've found this to be a helpful visual aid. ",
"http://4.bp.blogspot.com/-i94qZqIJolY... | [
"I like this one a lot."
] | [
"If only you knew my brother... this one didn't go over well, because he said playing the piano is a skill that is categorised differently from a physical trait."
] |
[
"When you taste something sweet after eating another sweet thing, the second thing doesn’t taste as sweet. Is that due to the taste receptors themselves not firing as often or is it your brain filtering out the signal?"
] | [
false
] | Also when you eat something salty and then other flavors are more intense, is that physiological or psychological? | [
"By \"psychological\" I'm assuming you mean further upstream in the sensory pathways.",
"On this timeframe, it's mostly sensory adaptation. Which is physiological. The receptor cells essentially get fatigued and don't respond as strongly to a second stimulus.",
"On a longer timeframe, it would be more psycholog... | [
"Salt actually does suppress the bitter sensation. So it can make fruit taste sweeter"
] | [
"Is that why some people roll cucumbers in salt, to suppress the bitterness of the skin?"
] |
[
"How likely is it that we will be able to manipulate/create wormholes for space travel?"
] | [
false
] | I feel like it's the only solution to the fact that we can't travel faster than light. | [
"There are two ways to solve the Einstein field equation. You can either start with a description of the matter, energy, momentum, fields and so forth over a region of spacetime then solve for the resulting geometry, or you can start with an arbitrary geometry and solve for the stress-energy tensor.",
"Wormholes ... | [
"It's not an intents-and-purposes, as-far-as-we-know thing. The answer's just plain "
] | [
"The universe doesn't give a crap what any of us want."
] |
[
"Why does my biology teacher tell us that the formation of bonds between atoms stores energy and the breaking of them releases it, when my chemistry teacher tells us the opposite?"
] | [
false
] | The chemistry teacher just says that the biology teacher is wrong, but there has to be a reason why it's taught. | [
"The chemistry teacher is 100% right, and the biology professor is half-right. Regardless of the bond (meaning, an attraction between atomic fragments), breaking it will require an energy expenditure and forming it will release energy. ",
"It is true that you can store energy in the form of high-energy (less st... | [
"Your chemistry teacher is talking about spontaneous chemical reactions. Your biology teacher is talking about the use of metabolic energy to drive reactions \"backwards\" which is done to create high energy bonds as a way of storing energy. Nobody is wrong, and they should certainly know that."
] | [
"The biology teacher is probably most concerned about how molecules like ",
"ATP",
" are used to store and transport energy around the body. ATP is said to contain ",
"\"high-energy phosphate bonds\"",
", however as the wikipedia article explains, this name can be misleading:",
"The term 'high energy' wit... |
[
"Is it possible and practical to create a new form of internet network, that would not require isp providers and so, would be protected from any filtering and censorship, by connecting individual computers directly between each other?"
] | [
false
] | This is a very old idea, liberating Internet from censorship and filtering. Around 10 years ago, when I was very fond of programming and computers some guy told me once, that Internet is something that can connect and unite all people. He said that Internet (the way it was back then) is an idea of free communication for everybody, and if Internet is ever to be censored, a new kind of network will evolve. Independent from isp providers, government entities and filters. A network that will interconnect every single computer directly. I think this idea is very actual today. The questions remain: 1) Is it possible to create such a system? 2) Is it practical to create such a system? 3) Is now a good time for such a system? | [
"Also ",
"/r/DarknetPlan",
" has a lot more info and is much larger."
] | [
"After the SOPA incident last year, many people realized that laws like that would eventually pass - and they were right.",
"Therefore, they set out to build a network precisely as you described, by using overlapping wifi networks to send signals from computer to computer. ",
"You can read more at the subreddi... | [
"Networking Engineer here, yes it's possible, in fact that's what the Internet is: a network of connected devices (sadly, it's not a series of tubes :( )",
"Now, is it practical?",
"Well first you must understand that for example if your machine has a public IP address, if I know it I can reach that machine fro... |
[
"Why can't spicyness be rinsed off easily?"
] | [
false
] | [deleted] | [
"It's not soluble in water, but it is soluble in fat. That's why milk works better."
] | [
"You need a non-polar solvent. ",
"Solvent Classification.",
"A girl I knew as an undergraduate accidentally got some spicy material on her recreational equipment (she went to the loo halfway through me teaching her to make Texas style Chilli).",
"We washed it off with a big 5 litre economy jug of cheapo cook... | [
"This is exactly why we use this word:",
"http://en.wikipedia.org/wiki/Piquance",
"Piquant vs. \"hot\" and/or \"spicy\"",
"Use of the word \"piquance\" eliminates potential lingual ambiguity arising from overlap in meaning with the words \"hot\" and \"spicy\" which usually requires a determination or assumpti... |
[
"What was the atmosphere like when dinosaurs existed? Could humans have breathed the air?"
] | [
false
] | null | [
"There are no direct measures of atmospheric oxygen from that period. There are a few ideas out there about potential ways to determine atmospheric O2 concentration that far back in time. They are: Stomatal density of fossil leaves; stable carbon isotope ratios of soil carbonates (pedogenic carbonate); stable carbo... | [
"You should link them, I'd love to see them. The 15%-35% number comes from sedimentary charcoal records - this is the oxygen concentration window within which combustion reactions can occur and form charcoal. The idea is that wherever there is charcoal in the sedimentary record, atmospheric O2 must have been betwee... | [
"Is the linked source accurate ? because other sources talk about 15%-35% oxygen during Cretaceous. "
] |
[
"Will humans one day be able to create a robot with ai that is conscious and self aware?"
] | [
false
] | null | [
"I've been reading up on articles such as the simulation argument, and wonder if we will get to the point where we will fully understand the workings of the human brain. I've seen plenty of statistics that say in years to come we will have the ability to create computers with greater computing power than the human ... | [
"I've been reading up on articles such as the simulation argument, and wonder if we will get to the point where we will fully understand the workings of the human brain. I've seen plenty of statistics that say in years to come we will have the ability to create computers with greater computing power than the human ... | [
"I believe that the answer is yes, assuming civilization does not collapse before then. Humans are just very complicated machines made of organic materials, so I see no reason why we won't be able to build something completely analogous with different materials. "
] |
[
"How are cepheid variable stars different from other stars?"
] | [
false
] | [deleted] | [
"A Cepheid variable star is a star that changes it's luminosity over certain period of time. This by itself does not make Cepheids different, since stars change their apparent magnitude over the course of their life.",
"However, Cepheid variable stars do this periodically and their period is tied with their absol... | [
"I'm just going to tack onto this response. While it's true that cepheid variables are among our most accurate distance measures, forming an important rung in the most precise cosmic distance ladder used to infer the Hubble constant from type Ia supernovae, they are still individual stars. This means we're limited ... | [
"Thank you, indeed, this is true.",
"However, I would just add that supernovae type 1a are currently being revisited, IIRC, and we might end up with conclusion that supernovae 1a are not actually as accurate as we believed they are. So, I would like to hijack this post and ask you if you know about this. I have h... |
[
"Why does our stomach start to growl when we get hungry?"
] | [
false
] | null | [
"Bilology"
] | [
"Bilology"
] | [
"The stomach is trying to process food, so it starts to move, but because there is nothing there to process, it'll create those noises. The term is referred to as, \"boborgymi\", IIRC, I'm not sure if I spelled it right, but I believe that's the general explanation in a nutshell. "
] |
[
"Can elastic deformation become plastic with time?"
] | [
false
] | For example, if a straight metal bar was deflected so that it was elastically deformed, is there any process that could lead to the bar not returning fully to its original state if it had been left deflected like that for a large period of time? I'm interested in both reasonably common external factors, and internal factors (imagining that the bar was kept in a perfectly controlled environment at standard pressure, temperature, etc). | [
"Materials can suffer \"creep\", which is slow plastic deformation over time. Rate of creep is mostly governed by temperature (and stress, of course). Most metals don't show appreciable creep at room temperature, and need to be heated to a significant fraction of their melting temperature before it becomes a proble... | [
"There are many mechanisms that could cause plastic deformations in a material over its elastic deformation range. One is fatigue. Repeated elastic deformations do cause changes at the molecular level that can eventually cause plastic deformations or even gross failures (like cracks).",
"https://en.wikipedia.org/... | [
"Yes, and you probably see it all the time in things like shelves around the house. With stronger materials this is less likely to occur but on a microscopic level weak spots in any material may fail fairly regularly. Elastic limits represent an assumed structure with anticipated makeup and microfissures. Constant ... |
[
"Why is cancer dangerous? Whats the problem with having uncontrolled division of cells? How does that pose a problem?"
] | [
false
] | null | [
"It depends on the organ and location of cancer. Keep in mind \"cancer\" is not a single disease but many different kinds, with different mortality rates. The danger can be from mechanical compression, metabolic changes, or combination of both. ",
"Brain cancer, for example, expands in a confined space, and will ... | [
"In addition to this, cancers can produce their own chemicals. Rogue hormone producing cells can signal the body to do things it wouldn’t otherwise do, as other cells in the body can’t differentiate between legitimately produced hormones and rogue cells. Cancer cells can also produce various toxins which can have ... | [
"Always worth remembering that tumours are physical objects; as they grow they can invade tissues or occlude vessels, like the trachea, bronchi, bile duct, blood vessels, anything really. ",
"If you've got a mass growing somewhere it shouldn't, it can push on bodily structures and impair the function. If it does ... |
[
"Why do we believe that a planet needs to have water for aliens to survive?"
] | [
false
] | I know this might sound a bit crazy but. Why is it that we are always looking for water or oxygen? Surely there must be a way for an organism to live without these two blocks and they may be able to substitute for them. I don't understand the saying "without water there is no life on other planets" Getting PMs that are saying only ignorant people say this well reddit your hero says it as well : What renders a planet, indeed, suitable for life? Well, clearly, you want a planet that has some water on it, because water is the cocktail mixer that allows the chemistry of our bodies to even work. : If we want a planet with liquid water, then it can't be too close to its star; that would make it too hot, and the water would boil away. And it shouldn't be too far away, either; too cold, and you'll likely get an ice ball.What everybody really wants to find is a little rocky planet, whose distance from its star is juuust right, a "Goldilocks" planet with oceans of liquid water. But hunting down a planet just like ours has been a daunting task. In fact, not long ago, we hadn't found any planets beyond our solar system, none at all. They're so far away and so dim, they get lost in the glare of their own suns, the stars they orbit. Source : | [
"We don't believe that a planet needs to have water for aliens to survive. We do know that all lifeforms we have ever encountered need water to survive. We therefore (with only one piece of data) look for what we know.",
"Say, as an analogy, you found an unlabeled cardboard box on the street and somebody told y... | [
"Water has multiple advantages that are beneficial to the formation of life. ",
"One is its very high specific heat capacity, it needs a lot of energy to change it's aggregate state. This helps because it allows water to remain fluid while solved molecules are provided with the energy needed to react. Its boiling... | [
"Water may not be absolutely necessary, but it's good choice. You need complex chemistry to have life and if you need solution where the reactions should take place, water is very good neutral candidate. Other possible solvents that are sometimes considered are: ammonia, methane, methanol, hydrogen fluoride, hydrog... |
[
"Do plug-in electric vehicles have a smaller carbon footprint than hybrid vehicles?"
] | [
false
] | null | [
"Except that burning fossil fuels at one large, efficient plant generates less carbon than burning fossil fuels in many small, inefficient plants. "
] | [
"You open up a whole can of worms with that. Imagine the variables, where the oil was extracted (tarsands, middle east, offshore) vs the coal (cost of human life(s), mountaintops, surface mining). The impact of refining and transporting oil while coal is more domestic. You could go on and on but I just can't ans... | [
"That depends on where you're getting your home power from. If you're local power comes from fossil fuels then I can't say for sure whether a hybrid or an electric would have a smaller footprint. If the power in your home comes from a renewable source then of course the plug-in will have less of a footprint. ",
"... |
[
"If temperature is the average speed of particles, why is there \"wind chill\" and not \"wind warmth\"?"
] | [
false
] | Forgive my ignorance, but I would think that if it were windy, that would mean that you would be feeling particles hitting you at a much faster average speed than if there were no wind. So why does it actually feel colder, instead of warmer? And does this effect only apply to air that's already cold? If hot enough air blows at you, will it feel warmer than it would if it were stationary, for instance? | [
"From a ",
"previous post",
":",
"When it's windy, it feels colder because normally in still air your body will heat up air that is semi-trapped around your skin; the more the air heats up, the less heat you are losing and the warmer you feel.",
"When it's windy, the air doesn't linger around your skin, and... | [
"At room temperature, the average speed of molecules of air is ",
"993 miless per hour",
", so wind speed has very little effect on the temperature of the air.",
"Wind chill is caused by the evaporation of water from the skin, which is increased when a breeze blows on it and decreased when the air is humid."
... | [
"Check ",
"this",
" out."
] |
[
"Scientists of reddit! Settle a bet for me. What affects the temperature of the seasons if it's not the tilt of the earth on its axis?"
] | [
false
] | Cross post from askreddit, wasn't sure where I should put this. At stake in this bet: the very usefulness of Reddit. My friend thinks we are all sexless geeks. Prove him wrong by showing him how geeky you are! Whoever answers this question first (he's asking books, pshh) wins. Here's what I think I understand: The tilt of the earth on its axis of rotation makes the seasons, because of the angle at which sunlight hits the planet's surface. So the less sunlight the earth gets (shorter daylight duration + the more acute the angle at which it hits the earth's surface), the colder it is, right? But here's my question: The shortest day of the year, the winter solstice, comes in early December. It begins the winter season. If the thing I said above about sunlight were true, the winter solstice would come smack dab in the middle of winter--the coldest day, the least sunlight. So what is it that makes winter last until March, getting progressively colder until then, if the earth is getting progressively more sunlight during that time. Residual cold in the oceans? Please someone explain to me! | [
"Check out what's called ",
" for the answer to your question. In a nutshell, it's the oceans and the rate at which heat radiates away versus stays."
] | [
"the earth's eccentricity is very minute.",
"from wikipedia\n",
"http://en.wikipedia.org/wiki/Season",
"\n\"Compared to axial tilt, other factors contribute little to seasonal temperature changes. The seasons are not the result of the variation in Earth’s distance to the sun because of its elliptical orbit.[2... | [
"All orbits are elliptical.",
"If you look really closely there are deviations from that, but elliptical is the general form."
] |
[
"Do space launches account for the flight path of existing satellites?"
] | [
false
] | As more satellites are launched into space I would imagine that there is an increased risk for collisions. Is there a map of current satellites as well as space junk? | [
"To an extent yes. As for a map of space debris, this is publicly available at ",
"https://celestrak.com/",
". Celestrak publishes the ",
"Two Line Element sets",
" for everything that is observable to the ground (with only a few items missing such as a handful of spy satellites I believe). These TLEs gi... | [
"Yes, mission planners and FAA know the orbits of all active satellites and keep track of dead ones and debris. When putting up new satellites, orbital altitude is set so that two objects don't cross paths (never guaranteed, but they get the probability really low).",
"If a close approach is detected, one or both... | [
"Then you end up with a ",
"huge cloud of orbital debris",
" that will cause problems ",
"for decades to come."
] |
[
"Are the effects of different carcinogens/mutagens cumulative?"
] | [
false
] | I joke with people that I'm not overly cautious about lab safety (e.g. I don't freak out if I spill a drop of benzene on myself, though I do wash it off immediately) because I smoke cigarettes, so it's not going to be the benzene that kills me. Is that actually true, or are the effects cumulative/additive, assuming it's the same tissue (e.g. inhaling residual benzene fumes & cigarette smoke)? Does it depend on the type of DNA damage (like oxidative vs UV, and/or deletions/insertions vs DSBs)? Or does that not matter, because all of them can result in changes that can result in cancer? | [
"Cancer is extremely complex. It is characterized by a number of different changes within the cell such as self-sufficiency of growth factors, evades apoptotic signals, immortality, able to metastasize, etc. Each of these characteristics are controlled by large pathways, and dozens of proteins. Therefore, there are... | [
"Cancer cannot occur from a single nucleotide mutation but requires at least 3 modified nucleotides, although some estimates are higher. The type of mutation is very important but in general the effects are cumulative. The only exceptions are when either the damage is repaired or the effect induces apoptosis or nec... | [
"What's the underlying principle that means cancer can't occur from a single nucleotide mutation? "
] |
[
"This article seems highly sensationalized. It's about using quantum computing to break complex encryptions. Is this actually any threat?"
] | [
false
] | null | [
"No. It is true that quantum computers can do prime factorization in polynomial time (\"quick\"), ",
"something we have known since 1994",
". However, we are nowhere near building a quantum computer powerful enough to do this.",
"There are other cryptographic systems which are not easily broken by a quantum c... | [
"Even then there are techniques based on physical properties of circuits that could be used to encrypt data.",
"And bear in mind that P doesn't mean it's fast. If there an algorithm requires N",
" to break and N to use, it is practically secure even if it's in P."
] | [
"In general, if you cite NaturalNews on any matter whatsoever, you are almost certainly wrong."
] |
[
"What would happen if every mosquito on earth dropped dead right now?"
] | [
false
] | This includes every mosquito egg, larva, etc from every mosquito species. | [
"Depends on the region you are considering. In the arctic, which has very low species richness, you would have removed one of the key links in the very short food chain. Migratory song birds which feed of the adults would go hungry and probably fail to breed. Char and lake trout who feed off the larvae and nymphs w... | [
"Mosquito disappearance might have negative impacts of short term (several years) macroinvertebrate species richness but would more than likely be overcome by increases in other benthic Dipteran populations that inhabit similar environments. Behavior change would occur with predators who primarily fed on mosquitoes... | [
"Can you provide some sources on migratory song bird feeding behavior in the arctic? The last I've read about their feeding behavior is that it is mostly comprised of Tipulidae and/or larger insects. Also, please show any evidence for fish feeding on mosquito hatches. Many mosquitoes in arctic regions hatch out in ... |
[
"If there's no up or down in space, do other planets rotate horizontally compared to earth?"
] | [
false
] | [deleted] | [
"There's no \"east pole\" because of the way \"north\" is defined. North is the direction around which you rotate counterclockwise. Always. The angle between a planet's north pole and the solar system's north pole is called the ",
", or axial tilt",
". It's surprisingly easy, over the long term, to tilt a p... | [
"Uranus' rotational axis is pretty much at 90 degrees to everything else (more than, in fact)."
] | [
"All of the solar system (sun, planets, moons, astroids, etc) came from the same starting material (a protosolar nebula) , and that material shared angular momentum.",
"Because of that, you find that pretty much everything in the solar system is more or less on the same plane, rotating together. There are of cour... |
[
"Why is Hawking Radiation limited to black holes?"
] | [
false
] | [deleted] | [
"Because it's crucial that there be an ",
" - a surface inside which light can't escape. No horizon, no Hawking radiation. The usual picture (it's not perfect, but it's a nice analogy) is that Hawking radiation happens when a pair of virtual particles pops up near the horizon. These virtual particles are constant... | [
"It's more that the event horizon doesn't allow the virtual particles to get back out, and annihilate with their partners. This produces a single well-defined boundary - the event horizon - from which Hawking radiation is emitted.",
"In the case of a very strong gravitational field that's not a black hole, there... | [
"It's more that the event horizon doesn't allow the virtual particles to get back out, and annihilate with their partners. This produces a single well-defined boundary - the event horizon - from which Hawking radiation is emitted.",
"In the case of a very strong gravitational field that's not a black hole, there... |
[
"How come our muscles get tired even when no work is being done?"
] | [
false
] | If for example there was a large heavy rock rolling down a hill, and someone were to hold it in equilibrium, afaik no work would be done in the act of just holding the rock in position. But something like that would still obviously cause the person's muscles to become fatigued. What's going on? | [
"If we were a solid object we wouldn't be doing work, but the human body is made to be able to move. We could have been made like robots who could \"lock into position\" and so not do work when holding stationary, but the evolutionary solutions is muscles that contract, so that even if we are not moving on a large ... | [
"Even a robot locking in position may need to exert some power to keep part of the robot in position.",
"A human standing still will still need to maintain some muscle tension as most joints have muscles on both sides. Eg the lower arm is lifted with the biceps and moved back with the triceps. It's near impossibl... | [
"Yep. I've worked with all kinds of motors and power transmission. If it's direct-drive or low reduction, you'll need a motor brake or some external braking system, otherwise it will generally freely move. An outside force which meets with a braked system will be stopped unless there's enough energy there to overco... |
[
"Theoretically, could a person's head or brain be kept alive and conscious separated from the body?"
] | [
false
] | null | [
"It's never been done with humans, but monkeys, dogs, and rats have had their heads severed from their bodies and kept alive. (",
"source",
")."
] | [
" the whole brain could be kept alive without even the head, which is why philosophical arguments like \"brain in a vat\" do not violate any scientific principles (note that it's still not science, since it's not falsifiable). The point is that we can already replace real stimuli with electrical impulses to the sa... | [
"Artificial lungs are in animal testing stages, and artificial hearts already exist!"
] |
[
"What was the Vacuum Catastrophe and what is vacuum energy density?"
] | [
false
] | [deleted] | [
"This is a bit of a handwavy argument in Cosmology and Particle Physics, which says that from quantum field theory, we expect the energy density (basically what it sounds like: how much energy you have per cubic meter of space, or some other preferred unit) of the vacuum to either just be zero, which intuitively ma... | [
"It's funny, I just got to the office now and a colleague of mine pointed out ",
"a paper",
" that came out today by a guy who has a seemingly really nice and common-sensical solution. The solution he suggests is that basically only very large wavelength modes have an effect on gravity, so we're doing this calc... | [
"This paper is a fully scientific paper, aimed at experts, so don't feel bad if you find it difficult! To be honest, some of the stuff is going over my head too. Luckily my colleague knows this stuff really well."
] |
[
"Is there a limit to calorie intake in a period of time?"
] | [
false
] | Does the body have a limit of calories in can store from food consumed in a certain amount of time? What I mean is, if I eat within 1 hour say 50,000 worth of calories (say I'm eating high calorie nuts like cashews and pecans). After some time the food is digested and removed from my body. During this period, did my body intake 50,000 worth of calories? Is there a limit? is it dependent or something else? | [
"If you were to consume 50,000 calories, the densest form you could eat it would be pure fat, which would be roughly 12 pounds of pure fat (9 calories per gram of fat). Your body would likely slow down your speed of motility of the fat from your stomach to your intestine so that there would be enough time for it to... | [
"This.",
"You'll just have to sit on the toilet for a ",
" long period of time if you do eat that. Unless your stomach is the most powerful stomach in the world, then you'd be storing all of it."
] | [
"All animals have a maximum rate that they can sustainably absorb energy from food. For human endurance athletes, ",
"http://jeb.biologists.org/content/204/18/3183.full.pdf",
" says that the physical activity level (PAL) maxes out at about 4-5. PAL is defined as \"average daily metabolic rate as a multiple of ... |
[
"How do we know there was a single common fish ancestor that got out of the water, and not several?"
] | [
false
] | How do we know it was just one, and not several of them in different situations? That would explain the different evolutional trees occurring. | [
"The premise isn't necessarily that we're descended from one single \"Fish\", but rather that we all evolved from one single \"Something\" at some point.",
"We can look at shared features and shared DNA that carries from one ancestor to the next and we can measure the differences within and between groups.",
"S... | [
"Well lots of fish come out of the water, you've got mudskippers and walking catfish for example. And there probably were multiple fish coming out onto land going way back to the first land vertebrates. ",
"But we know that, eg, birds, mammals, amphibians, and reptiles didn't all come from separate colonization... | [
"we don't know that it was only one. There's a number of fossils of things that are intermediate between a totally aquatic fish and a 4-legged amphibian. A lot of the time, we only have a few specimens here and there, and we connect the dots beteeen them to make a single trail. But, some are from the same time as e... |
[
"Does it take more energy to heat a house/apt by turning the thermostat off when you leave, or just turning it down slightly."
] | [
false
] | If it is better to turn the thermostat down slightly, then how much? In both cases, how come? Does the size or layout have an effect? | [
"The purpose of the furnace is to replace heat lost through the walls and roof of the house. The rate of heat loss is proportional to the conductivity of the wall material, the area of wall, and the temperature difference. ",
"The first two of those you can do nothing about, but the smaller the temperature differ... | [
"Agreed, and as a cautionary note, if you live in a cold climate and turn the heat down too low, you risk water freezing in the pipes and bursting them."
] | [
"You could imagine that there could be some set of temperatures (rather than 55, 60, and 68) where it's more efficient to keep the heat higher.",
"There is no circumstance in which it is more efficient to keep the heat higher. The higher the temperature, the more heat is lost. The purpose of the furnace is to rep... |
[
"Antibiotic Resistance - how does that work on the individual level?"
] | [
false
] | To simplify my question, I always tried not to take antibiotics (or general medicinal drugs for that matter) unless I have to, under the notion that if i ever do need to take antibiotics, it will have a stronger effect on me, possibly helping me overcome health problems that would otherwise take longer to cure. So my question is, does avoiding antibiotics (or similar drugs) until absolutely necessary the smart thing to do? or should I just take them anyway whenever there is a slight need, since it actually doesn't matter? | [
"You should take antibiotics only when prescribed by a doctor, but when prescribed, take the entire course as directed. ",
"You seem to have a common misconception - you don't become resistant to antibiotics, the bacteria that are infecting do. If you don't take them as directed, the chances of ",
" becoming re... | [
"On an individual level it is always better to take the antibiotics (if we only look at resistence). Its only bad for the population. However, since everyone is part of the population it will have also an effect on the individuals of this population. \nAntibiotic resistance (mostly) do not effect pathogenicity, the... | [
"Thank you, that is pretty much what I was wondering but could not phrase correctly myself. that clears that up for me!"
] |
[
"If all substances try to move towards the most stable state, why do we have substances that are not stable in the first place?"
] | [
false
] | null | [
"Some substances can be trapped in what is known as a \"kinetically bound state\". It's an energy state that isn't the lowest, but the substance stays there anyway. There is always an energetic cost to convert from one state to another, and sometimes it is just too high for it to happen.",
"Diamonds are an exampl... | [
"Imagine a slope on the side of a mountain that is perfectly smooth. You put a ball on it. What happens? It'll roll down the hill.",
"The top of the mountain represents the high energy state, the bottom represents the low energy. Remember that high energy = least stable, and low energy = most stable. As we can se... | [
"It has to do with conservation of energy. If you place a ball atop a frictionless U-shaped hill, it will roll towards the \"most stable\" state at the bottom, but then once at the bottom, kinetic energy will carry it back up to the top on the other side. \"Stability\" is just a lower energy state, and the energy... |
[
"This may sound stupid but do animals of the same species that have lived in different countries have the same \"language\"?"
] | [
false
] | null | [
"Not a stupid question, there's a lot of research going on in to that exact question. Here for example we see that the mating calls of cricket frogs are different depending on where they live, due to adaptation to environments with different acoustic qualities ",
"geographic variation in Animal communication syst... | [
"To distinguish a 'word' as apart from a 'call'.",
"For example, perhaps a species of monkey has a general call which means 'danger' but a species of chimp living in the same jungle can say 'danger jaguar!' 'danger snake!' etc. That is the calls carry more information than just general mood. Strictly I should hav... | [
"You're sarcasm a) isn't suited for this sub and b) shows a lack of understanding of my question. You're either being willfully obtuse or don't understand that I was very clearly asking about regions. Human beings didn't look at a map and say \"let's speak a new language\" different methods of communication develop... |
[
"Asteroid planned to 'hit' earth next year. How likely is this?"
] | [
false
] | Taken from this article; How likely is that the impact will happen? Has this asteroid been in orbit of our solar system? Follow up: If this is a hoax, say that an asteroid this size will hit earth, what will the damage radius be? | [
"The article is a hoax. Ignore it.",
"DA14 is a -3.29 cumulative on the ",
"Palermo Scale",
". Anything under -2 is not considered something to be given serious impact consideration. In other words, not even worth mentioning.",
"Answering your other question... Even if you assume the worst about the makeup ... | [
"Fantastic input and elaboration on this subject, thank you very much for this thorough explanation!"
] | [
"Not a 'hoax' per se. The asteroid in question is on the Official NASA Near Earth Object Program site.",
"Definitely sensationalist and alarmist wording in the article, yet, their assertion that there is little that can be done in the next 11 months while inappropriate in the context of impending doom, is not ina... |
[
"What is the largest an animal could possibly be?"
] | [
false
] | I was reading about the largest organisms in the world on wikipedia and got to thinking. I know that on Earth, an organism's size peaks out because at a point they can't have enough muscle to keep themselves standing. Just making something bigger and bigger doesn't work, so no King Kong is going to happen here on Earth. But on a planet with lower gravity, or a different atmospheric makeup, could larger and larger animals be possible? Is there a point where, regardless of the environment the creature is in, it's not possible to be any bigger? That the creature would collapse under it's own gravity, or biological processes just would not function anymore? | [
"There is a whole (contentious) field of study that kind of asks this question called ",
"allometry",
". ",
"Basically, it says that many things scale at very different rates. For example, if you increase the size of a sphere, the surface area increased at a rate of ",
" while volume increases at a rate of... | [
"I always thought it was heavily related to the amount of oxygen in the air."
] | [
"I wish I could give you a good response, but whatever I say is going to be mostly speculation (I've only read a couple of papers on this subject).",
"But, for some reason, I ",
" that since diffusion is still required, even just at the capillary scale, there are still problems. ",
"Sorry for that unsatisfyin... |
[
"How much sleep is really necessary for one to get through the day?"
] | [
false
] | I tend to get only about six hours of sleep a night. With a coffee in the morning and possibly an energy drink in the afternoon I'm able to handle a full day of high school plus the commute to my school without getting too tired. How much sleep to we really need to function with a decent amount of energy? | [
"Adolescents, children and young adults require more sleep than middle aged people do. A typical high school student requires 8.25 to 9.25 hours of sleep a night. Lack of sleep has negative effects on health and intellectual functioning.",
"http://en.wikipedia.org/wiki/Sleep#Optimal_amount_in_humans",
" "
] | [
"I would define it as without getting worn out of tired. If I were to get really drowsy during the day and maybe fall asleep in class, I would consider that not decent."
] | [
"We don't understand sleep very well. We can only assess skills and then ask how much sleep they believe they got and draw a correlation (both with general IQ and changes in amount of sleep). Your question asked both about \"functioning\" and \"getting through the day\". How do you define functioning or getting ... |
[
"How are satellite images captured and edited?"
] | [
false
] | [deleted] | [
"There are tons of Earth observation satellites, many with regular cameras for natural color images. There are some ",
"free images",
" and then some ",
"better images if you pay for them",
"."
] | [
"Landsat images are different than what you’re looking at, as they have specialized uses. They’re multi-spectral, meaning that they’re taken in specific colours (and often outside human vision range), with the specific intent of seeing large scale features on earth. Different plants are different greens, and absorb... | [
"Landsat images are different than what you’re looking at, as they have specialized uses. They’re multi-spectral, meaning that they’re taken in specific colours (and often outside human vision range), with the specific intent of seeing large scale features on earth. Different plants are different greens, and absorb... |
[
"How small could you compress the universe if the fundamental forces didn't exist?"
] | [
false
] | The only thing holding atomic nuclei apart is electrostatic forces, right? (Ignoring kinetic energy for electrons and things). Is there a similar deal for quarks/leptons? If the 4 basic forces stopped working, could an atomic nuclei be condensed? Could a hadron? How about a quark, or a lepton? Could the whole universe be condensed to a point, or do things at that level actually touch each other in some way? | [
"If the 4 basic forces stopped working, could an atomic nuclei be condensed? Could a hadron? How about a quark, or a lepton? ",
"No, not without a lot of energy at least. ",
"All quarks and leptons are fermions, and fermions cannot occupy the same state - it is called Pauli exclusion. If you want to start putti... | [
"In fact, on the order of half of the resistance of a common metal to being compressed comes from Pauli exclusion, not from electrostatic repulsion.",
"Damn, that's very interesting. ",
"I'm a bit confused. Say you have a point location, and you put a fermion in it with the lowest possible energy. If you took a... | [
"Electrons are also subject to the pauli exclusion principle."
] |
[
"Is the space-elevator just a \"pipe-dream\"? Why, or why not?"
] | [
false
] | null | [
"The material strength requirements are a bit unrealistic, they have to start imagining things like carbon nanotubes that are a hundred miles long, with no defects. ",
"Seems pretty pipe-dreamy to me."
] | [
"They have strange properties, although immensely strong in the axial direction, they are quite weak in the radial direction. Although a 1 mm nanotube cable could hold more than a ton of weight, you could probably cut it with a dull pair of scissors. Any sort of shear forces would be a big problem (like say wind?... | [
"They have strange properties, although immensely strong in the axial direction, they are quite weak in the radial direction. Although a 1 mm nanotube cable could hold more than a ton of weight, you could probably cut it with a dull pair of scissors. Any sort of shear forces would be a big problem (like say wind?... |
[
"What is the ghosting i feel after a day on roller coasters?"
] | [
false
] | today, i visited a theme park, and spent a good chunk of my time upside down, spinning, and falling. Every time i do this, that night, tonight included, i feel the exact same G-forces applied to me. pressure to my head, then pressure to my rear and feet. it washes. this "ghosting" starts as soon as i settle down for the night, and lasts for hours. oddly enough, it doesnt start until a few hours after leaving the park and being home. is it an inner ear thing? i would think my ear would have settled down after an hour or so of riding. is this common, and what the heck is going on? | [
"Inner ear makes sense, you have small stones that sway when your head moves.",
"The other is that all the swirling has created some current in your cerebrospinal fluid. maybe more or less of it gets reabsorbed when you jostle around and you're high or low."
] | [
"you have small stones that sway when your head moves.",
"Wait what? I'm guessing I missed that chapter."
] | [
"http://en.wikipedia.org/wiki/Otolith"
] |
[
"Does Alzheimers/Dementia affect muscle memory?"
] | [
false
] | Sorry if this is a stupid question, but do memory loss diseases affect motor skills/muscle memory? Or is something like that lost when other memories are lost. Thanks | [
"Hmm the answer here is dual. Technically yes, but not for the reason you'd expect. ",
"What people (and probably you as well) think of when they think of Alzheimer's is a memory disease. This is because Alzheimer is a neurodegenerative disease, and the hippocampus is among the first areas that get compromised."... | [
"I asked mum (who is a nurse in an aged care facility) and she said that muscle memory does get affected. ",
"So, I went I look up a couple of sources, and found this for you!",
"https://www.reddit.com/r/askscience/comments/2dd7rj/do_alzheimers_patients_lose_muscle_memory_as_well/?st=ISEBARX3&sh=6db2289b"
] | [
"Muscle-memory isn't \"muscle-stored memory\". When you train your muscles, you're really teaching your brain how to properly activate and coordinate the motor neurons that activate muscle.",
"Yes, your muscles seem to \"know\" what to do, but that's because your brain has learned the pattern and will just repea... |
[
"What exactly causes burns?"
] | [
false
] | I understand that burns can be caused by a variety of different sources (radiation, chemical, electrical, friction, etc.), and it seems that most of these are in some way related to temperature extremes. So why do all these different sources cause similar injuries? Is there a similar underlying cause? If so, what is that cause? | [
"In addition to heat, chemicals (specifically acids/bases) and radiation (including UV light) can cause protein denaturation leading to a burn. After the initial injury (heat/chemicals/etc) the body reacts by producing an inflammatory response which leads to blisters, swelling, and many other changes we associated ... | [
"You can check this out for yourself by cracking open a raw egg and throwing ethanol on the egg. It'll slowly turn into a normal cooked egg. It'll go even quicker if you throw an acid on it. (However, don't eat said egg.)"
] | [
"Temperature changes such as extreme heat denatures proteins, which means they unfold and reform their shape at certain pH's and temps. Naturally, this kills the cells and skin layers that these proteins are made of. That's what causes protein-rich food like eggs to cook as well."
] |
[
"If I have to wake up in 30 minutes, is it worth going to sleep now? At what point (if any) would it be better to just power through the night?"
] | [
false
] | null | [
"Studies suggest that 20 minute naps are ideal for a quick energy boost. If you go beyond that you have a high chance of waking up in a deeper sleep state and end up with something called 'sleep inertia', which is something that makes you feel groggy. Waking up in sleep stage 1 is ideal.",
"Reference: ",
"https... | [
"The broad answer to this is REM cycles, but with as little time as 30 minutes, you're probably better off with a \"nap\" than a \"sleep\"...some people can train themselves to enter a state just short of sleep that can be significantly restorative with just 10-15 minutes. As for powering through the night, it's g... | [
"That's interesting, thanks! How would someone enter and keep themselves in a state just short of sleep? If I went to lie down at 5:30am I would definitely just fall asleep instantly. How would one enter this mental state and nap instead of just sleeping?"
] |
[
"What shape is the universe?"
] | [
false
] | null | [
"The ",
" universe is a sphere of radius 46.5 billion lightyears centered at Earth.",
"What do I mean by the observable universe? Well, the universe is currently 13.8 billion years old. The furthest objects we can possibly see are ones whose light was emitted 13.8 billion years ago. But due to the expansion of ... | [
"We haven't found any evidence of this yet, but it's one of the stranger possibilities. :)",
"Actually, it's one of the most normal possibilities there is! There are three most-basic geometric shapes the Universe could be: flat, open, or closed. Flat is what you'd expect, \"normal\" 3D space (plus time). Open is ... | [
"We have also looked for light echoes from a closed universe, where light moving in a straight line through three dimensional space eventually comes back to its source from the opposite direction. Stare far enough, and long enough into space in any direction and you see the back of your own head. :)",
"We haven'... |
[
"Has there been a disease that was beneficial to humans?"
] | [
false
] | null | [
"It depends on how you want to interpret that question. Let's take a classic example: ",
"sickle cell anemia",
". Individuals who carry both alleles for sickle cell have the disease, which is serious. However, individuals that have only one allele for SCA are protected from ",
"malaria",
". ",
"So is ... | [
"From a certain point of view, there's an interpretation of how the Black Plague helped the 50% of Europe who survived it (from ",
"http://www.livescience.com/2497-black-death-changed-world.html",
")",
"Social effects of the plague were felt immediately after the worst outbreaks petered out. Those who survive... | [
"Early 20th century physician Julius Wagner-Jauregg used malaria to 'cure' syphilis. It was known as ",
"malariotheraphy",
". He won a ",
"Nobel Prize",
" for it."
] |
[
"Why does soda/soft drink go flat only when opened?"
] | [
false
] | [deleted] | [
"The partial pressure of the carbon dioxide in the liquid in greater than that of the atmosphere. The pressure will equalise and therefore the carbon dioxide will leave the liquid, making it go flat.",
"This is why the bottles are pressurised when you buy them. The increased pressure balanced the partial pressure... | [
"You could use tonic concentrate / quinine syrup / other bitters and mix it with soda water at time of use— I actually enjoy operating a soda siphon, the soda in them doesn't go flat quickly (since it stays pressurized), they're cheap to operate, and the siphons look nice in that early-mid-20th-liquor-sideboard way... | [
"You could use tonic concentrate / quinine syrup / other bitters and mix it with soda water at time of use— I actually enjoy operating a soda siphon, the soda in them doesn't go flat quickly (since it stays pressurized), they're cheap to operate, and the siphons look nice in that early-mid-20th-liquor-sideboard way... |
[
"Is it feasible to make a nuclear powered steam train?"
] | [
false
] | By using the heat of radioactive decay to boil the water. Or would it be more effective to use that energy to power a turbine that then powers an electric engine? How would one look? Obviously no tender needed for coal, but would it be heavier because of the shielding? What if it runs out of water? I'm picturing this massive black beast at the station, that leaks steam and hums gently due to the reactor. :P EDIT: Just to clarify. I just want to know if I can get a steam engine running by using radioactive decay as a heat source instead of burning coal. | [
"It's not impossible, but it's probably unfeasible. ",
"There's patents and designs for all sorts of these things- nuclear powered ",
"space ships",
", ",
"submarines",
", ",
"planes",
", ",
"trains",
", (plantains?) etc etc. ",
"That last link about nuclear trains is something I found in the ne... | [
"There were a number of issues. The plane could certainly fly with the added weight and shielding, but this limited payload capacity, maneuverability and performance (and thus survivability). Additionally, even if you could carry enough energy content to fly indefinitely, flight crews could only loiter for so long ... | [
"You can make a fairly small nuclear reactor. I believe I have seen estimates as low as 500 watt as the smallest feasible fission reactor. Certainly this might be more expensive than a gas turbine or diesel engine, but practically speaking the design of reactors allows them to be much smaller than most people think... |
[
"How long would an astronaut have to be on the ISS to experience one second of time dilation from those of us on earth, due to relativity?"
] | [
false
] | I was just listening to where he mentions how many times the ISS went around the earth while he was onboard, and this thought popped into my mind as I contemplated traveling at that incredible velocity for an extended period of time. | [
"About 90 years."
] | [
"Calculate the Lorentz factor, substitute 8 kilometers per second for the velocity, subtract 1, divide a second by the result."
] | [
"This graph",
" on the Wikipedia page for time dilation is helpful. The x-axis is orbital altitude (in Earth radii) and intersects the y-axis at 1 (Earth's surface). The y-axis is how many microseconds they lose per day.",
"I don't like how the altitudes (ISS/GPS/GeoStat) are horizontal lines. They should just ... |
[
"Is there a way to estimate thermal properties of theoretical alloys?"
] | [
false
] | I am currently working on a project that involves many metals melting and reforming into a solid. It made me wonder if there would be a way to estimate the new thermal properties such as conductivity of the new material. I originally tried a simple weighted average of the conductivities, but when comparing that known alloys it is an extremely poor estimation. I have found a lot of papers that propose methods for finding conductivities of alloys made up of two metals, but I am working with potentially much more. I was wondering if there was a way to estimate the conductivity of the new alloy or at least put bounds on it. Sorry if this is a simple question i have almost no experience with material science. | [
"Yes, you can use numerical techniques like Density Functional Theory or Molecular Dynamics"
] | [
"In principle yes, but even if you're an expert in the field you may occasionally estimate them wrong.",
"What you would first have to do is find out what the atomic structure is. Is it crystalline or amorphous? What's the crystal structure? From this you can get a good estimate of the conductivity and the phonon... | [
"As other commenters have made clear, this is a very difficult problem. You can use numerical methods like molecular dynamics but it's very computationally expensive and is hard to extrapolate bulk quantities from. You also have to make sure that you're accurately modeling your alloy on the atomic level. How well d... |
[
"Can I train myself like a dog?"
] | [
false
] | When you train a dog, every time he's successful, you can give him food, and he associates it with the success, so he gets better. Can I do the same with myself? Like, for instance, when I manage to play that guitar riff, I eat a M&M's. Will I get better that way? | [
"It's also not the same scale of task - learning (or wanting to learn) a guitar riff is not the same as telling a dog to sit. If he were to get someone else to reward him with something small like a treat for doing very small tasks, it would be similar. Rewarding yourself is related to motivation; rewarding in clas... | [
"It's also not the same scale of task - learning (or wanting to learn) a guitar riff is not the same as telling a dog to sit. If he were to get someone else to reward him with something small like a treat for doing very small tasks, it would be similar. Rewarding yourself is related to motivation; rewarding in clas... | [
"There's more going on internally with humans than with dogs (generally speaking) but lots of child rearing techniques use similar techniques of small 'token' rewards for specific behaviors, which over time breeds more of the desired behavior. You can certainly use rewards as a way to motivate yourself, but it's no... |
[
"Research has been done on the effect of gut microbiome on behaviour. Has any research been done on the effects of sharing elements of one's microbiome with a partner, through things like kissing and oral sex, might have on behaviour within the relationship? [medicine] [human body]"
] | [
false
] | See title | [
"We know that the microbiome does spread from person to person. In fact, a simple kiss can transfer thousands of bacteria. I can think of two effects this would exhibit on your health and behavior.\nFirst, as two peoples' gut biomes align, they would start craving similar foods. As far as we know, the strongest be... | [
"Lol, I have a bunch on this for a post I was saving. To answer your question, not specifically for behavior that I’m aware of, but a previous commenter got it right that our dogs GI microbiome mimics their owners. ",
"The punchline of my eventual post is that cunnilingus may be a source of probiotics."
] | [
"I know that there are studies that show that people who live in close quarters do have more similar microbiomes, not only from kissing etc, but also from sneezing, fecal particles being spread, etc. \nI also remember hearing something about a study comparing microbiomes of pets and their humans, but I can’t rememb... |
[
"Is sad music sad because we grew up associating it to sad movies? Or is it because the melody is objectively sad?"
] | [
false
] | null | [
"It's the dissonance. The pitches of minor chords are not in very symmetrical frequencies. This dissymmetry is somewhat unappealing to the ear, and is therefore associated negatively."
] | [
"I'm thinking because maybe they use minor keys? Or they have a lot of different minor chords?"
] | [
"This leads to the next question: How is it that minor keys seem sad to many?"
] |
[
"Can characteristics of same plant species vary from one place of growing to another?"
] | [
false
] | I'm just reading about some plant healing effects, how it's less effective if it was grown in Europe instead of Egypt, and I find this absurd. | [
"Yes, plenty of plant attributes change depending on light availability, soil composition, local competition, weather, nutrient availability, water availability, etc. While every plant species is different, most are highly adaptable and can change in significant ways depending on environmental context. As a general... | [
"I got my bachelor's in ecology, but I know very little about herbal remedies. So I can't really give an informed testimony on the 'synthetic vs herbal' argument. But at face value, that statement seems like it could hold some water"
] | [
"So is it also the argument in favour of synthetic medicine that uses same active ingredients for its effect as herbal remedies over said herbal remedies? Since that implies that herbal medicine could have doses that vary wildly, which can be dangerous in some cases. "
] |
[
"Would a laser that produces light outside of the visible spectrum damage your eyes in the same way a typical colored laser would?"
] | [
false
] | null | [
"Yes, it can actually be more damaging because with a visible laser your blinking reflex will protect your eye after the first fraction of a second."
] | [
"It depends on the wavelength.",
"Near IR has very similar effects to visible light, but, like ",
"/u/iorgfeflkd",
" says, can be more dangerous because it won't cause a blink reflex.",
"Other wavelengths cause other effects, due to being absorbed by different parts of the eye. I stole this table from ",
... | [
"Yes. In fact, any laser >5mW (ie pretty much anything other than your standard cheap red pen-style laser pointer) can potentially be pumping out enough scattered UV to damage your retinas",
"I think you're confusing UV (ultraviolet < 400 nm) with IR (infrared > 700 nm). UV cannot damage retina, as it is absorbed... |
[
"The old 'travelling at the speed of light and turning the headlights on' chestnut"
] | [
false
] | So someone posted an explanation to this problem here: . My question regarding it is here: | [
"You can't travel at the speed of light, period. If you're travelling very close and you turn on the lights, the light appears to be going at the same speed for you, and someone at rest. This is one of the principles of relativity, that the speed of light is the same in all inertial frames. If you're travelling at ... | [
"Another way of addressing it (which I personally prefer, but it's really a matter of taste) is that going from one inertial reference frame to a differently moving inertial reference frame is equivalent to a hyperbolic rotation.",
"In a circular rotation, the angles of rotation add; rotating something by thirty ... | [
"It would be better if you could state the question directly so people don't have to do a bunch of homework to find out what the question is."
] |
[
"What does AskScience think of stem cell treatments for organ transplant recipients?"
] | [
false
] | I'm interested to know what AskScience thinks of this study. My questions: | [
"Is there really hope for stem cell treatments to aid in transplant patients?",
"Most definitely there is. This is an active area of study and one that does show promise. There's a lot of unknown, and years of study ahead before this becomes common-place, but it's definitely something that is being examined. T... | [
"Thank you for this reply. The story's been in the news quite a bit lately (locally here in Chicago) and it's hard to tell what to make of it. When I first heard of the trial I thought it had been proven out in multiple cases but I can only find information on the one patient cited in the article. ",
"Just for cu... | [
"What are the challenges to self-grafts and cloning organs?",
"We don't have a reliable way to grow most tissue on a large enough scale to be able to provide what is necessary to replace tissue style transplants. Though a couple weeks ago there was a post about a trachea that was done this way, it was again a fi... |
[
"Why do people feel stiff when it rains?"
] | [
false
] | My muscles always feel tight when it rains and I've heard several other people complain that their bones ache. What causes this? | [
"When it begins to rain and as it rains, air pressure rises. This rise in barometric pressure causes more strain to be put on the muscles and joints in order to support the body as it will weigh slightly more. People who have arthritis, sprained muscles, or another ailment of the sort will be able to feel these cha... | [
"Changes in Barometric pressure."
] | [
"I would love to see the papers on this."
] |
[
"If I had a super precise weighing scale, would my weight change as I breathed in and out?"
] | [
false
] | [deleted] | [
"Yes, water leaves our lungs as we breathe out, also we breathe in O2 and breathe out CO2. You would lose weight for both reasons.",
"It wouldn't however be an up and down cycle, for reasons others have posted. It would be a slight drop with each exhale."
] | [
"To add to this, an average human being exhales ",
"250mL of CO2 per minute",
". Converting this to grams (and taking into account the oxygen you breathe in) you lose about 0.134g per minute. ",
"0.25 L * 0.001m",
" /L * ",
"1977g/m",
" * ",
"12g",
" / ",
"44g",
" "
] | [
"It doesn't so much 'ignore' it, as 'not include' it. He was talking about the CO2 only.",
"You can come up with a good approximation of the water losses (of respiration, you also constantly lose water by perspiration) by:",
"finding the tidal volume of your lungs (varies for each person, [units m",
" /breath... |
[
"If you could somehow evenly apply an increase in the rate of neuronal action potentials across the entire brain, what effect would that have?"
] | [
false
] | What effect would that have if you had a mild increase? moderate increase? severe increase? Would it be dangerous? Healthy? Would you 'use up' your brain faster (haha probably the least scientific way to describe this)? Would it 'fill up' your brain? | [
"There is actually already a well studied way to apply an increase in the rate of neuronal action potentials across the entire brain. ",
"Electroconvulsive Therapy",
".",
"But really at almost any level of intensity this would just be like giving someone a seizure. "
] | [
"What about TDCS or TRNS?"
] | [
"I heard the military was experimenting with tDCS for training drone pilots.\nHeres a related article.\n",
"http://www.newscientist.com/article/mg21328501.600-zap-your-brain-into-the-zone-fast-track-to-pure-focus.html"
] |
[
"How early do you think a child should learn about SR, GR, and QM? How about calculus, topology, complex analysis? What do you think is the most important thing to teach to a middle-schooler?"
] | [
false
] | null | [
"They should learn about them when they're interested in them. The most important part in my development as a physicist was that my parents made sure to encourage my curiosity. ",
"When I was kid I liked to take apart electronics, and they let me. I wanted to learn to program, they let me. When I wanted to to lea... | [
"Which geographic area, I mean. Your assessment strikes me as unlikely pessimistic."
] | [
"In my opinion, the scientific and math ",
" are much less important than a scientific mindset - critical thinking, critical analysis, problem solving, logic, and curiosity. ",
"If these cornerstones are developed, then all else will follow. ",
"Laying that foundation is a process that starts in infancy (yes... |
[
"What is the Physical Consistency of the Surface of the Sun?"
] | [
false
] | Yes, it's a big ball of plasma, but what is its surface like? If you had sufficient protection from the heat, radiation, and the like, would you be able to "stand" on it, like you could a solid? Or would it be more like a liquid that you could swim in? Or would you just fall through? | [
"If you have a magical space suit that can resist the pressure, you'd eventually reach a point at which you're neutrally buoyant and float, but otherwise you'd be compressed too and just keep sinking. The density at the Sun's core is 150 times the density of water but it's still a plasma with no solidity to it sin... | [
"You'd fall through; the ",
"visible surface of the Sun",
" is a gas (technically a plasma, but it would feel just like gas) with a density of 1/1000th of Earth's atmosphere at sea level, and there's no solid surface, it's just gas that gets denser and hotter the deeper you go, all the way to the core."
] | [
"The part of the Sun that people usually call the “surface” is the photosphere, which is the point where light coming from the core can finally move freely in a strait line. Really the Sun has no surface, it’s plasma all the way through.",
"If you were to become invincible and start falling onto the Sun, at firs... |
[
"Why is Athlete's Heart considered a benign condition whereas Hypertrophic Cardiomyopathy is potentially dangerous?"
] | [
false
] | More specifically, does anyone know what the underlying difference(s) are that would make the former 'benign', while the latter is considered the leading cause of sudden cardiac death, especially in athletes? | [
"These are pretty good answers, but there's a central idea buried in there that I just wanted to state outright:",
"Athletic conditioning gives you a heart that is slightly bigger, but much more efficient at pumping. Hypertrophic cardiomyopathy gives you a very big, floppy heart that is extremely inefficient at p... | [
"Athlete's heart is from conditioning, causing a strong and efficient heart. Cardiac output is high. ",
"Hypertrophic cardiomyopathy is genetic. The key is that \"the normal alignment of muscle cells is disrupted, a phenomenon known as myocardial disarray. HCM also causes disruptions of the electrical functions o... | [
"The response was already in the links you provided :",
"This is because athlete's heart is a normal, physiological adaptation of the body to the stresses of physical conditioning and aerobic exercise.",
"Hypertrophic cardiomyopathy (HCM) is a primary disease of the myocardium (the muscle of the heart) in which... |
[
"How can we really know the size of extra-solar planets?"
] | [
false
] | So we've found 3 'Earth sized' planets recently. If we find these planets by the wobble of the star, or by the dimming of the star as they pass in front, how can we tell the difference between a larger than earth sized planet, and an earth sized planet with a moon? like for example could these be pairs of smaller binary planets? How do they account for this? Massive Edit: Thanks for the responses! It seems like the general attitude is that it wouldn't make a big difference to the measurements anyway. The reason I asked this is because I've heard that having a moon could be, or is, either essential or greatly beneficial, to it's capacity for harbouring life. When people announce 'earth sized' planets, where they could actually be ever-so slightly smaller but with a moon, the implications to the probability of life outside our own solar system are huge. I am making a game about travelling to other systems to find planets, it's all based on a procedural system generator. So the probability of moons and life is super important for that, and just interesting to me, I wouldn't be making it otherwise. My tutor was like 'that's going to be super tedious and boring if it's based on science'. But the more we find out about them, the more it seems extra solar planets in general, and even ones that could harbour life, aren't as rare as people assumed. | [
"how can we tell the difference between a larger than earth sized planet, and an earth sized planet with a moon?",
"Bear in mind that the amount of light blocked by a transiting planet in front of its parent star is a function of the radius ",
", so it's not greatly affected by the additional presence of a moon... | [
"Earth has an exceptionally large moon for its size, too (if our own solar system is any indication)."
] | [
"A simplified version of the technical definition of a binary is that the system barycenter is outside the primary.",
"The Earth-Moon barycenter is close but not quite outside the Earth. It's ",
"73% of a radius",
" away from the center. Close, if you squint. So the Earth kind of 'wobbles' over the course of ... |
[
"Would an exploding/imploding star create a shockwave?"
] | [
false
] | I am aware that space is mostly empty and shockwaves would require matter to build up, but as a star expands during it's death would the matter being expelled create a shockwave, and could this shockwave push planetary bodies away from the star, creating a rogue planet? Or would they just be inevitably swallowed by the star? | [
"Well as I understand it space is not a void, and there will be massive amounts of matter released during the explosion at rapid speeds. could this be enough to cause a shockwave?"
] | [
"There is an entire area of astronomy geared toward studying what are called \"bow shocks,\" where the shock wave from a stellar event moves through the gas in the surrounding region of space. Bow shocks sometimes refer to the flow of surrounding gas around a star, and the resulting high and low pressure (and dens... | [
"While it wasn't a full blown supernova, these images of ",
"V838 Monocerotis",
" can provide a pretty decent idea of what one may look like. "
] |
[
"When measuring the mass of an electron (9.11*10^-31kg) is this the mass when the electron is at rest or when moving with relativistic velocity?"
] | [
false
] | null | [
"The modern definition of mass is a quantity which doesn't change with the speed of the particle. So the mass of the electron is the rest mass, which is the same no matter how fast it's moving.",
"We can't determine particle masses from first principles."
] | [
"I'm somewhat confused. From General Relativity we know that mass does change when approaching relativistic velocities. As an electron will always (I think) be moving with relativistic velocity, if it's mass at that speed is 10",
" kg, then at non-relativistic velocities the electron should have less mass, right?... | [
"From General Relativity we know that mass does change when approaching relativistic velocities.",
"This is only true using a different definition of mass; one which isn't really used anymore.",
"Electrons are not always moving at relativistic speeds, they can be moving quite slowly under everyday circumstances... |
[
"What happens if you throw an object during uniform circular motion?"
] | [
false
] | If you were holding an object (say a ball) and were travelling in a uniform circle (say on a roundabout) what would happen if you threw the ball? I know that if you just let go of the ball, its force would be its centripetal force in the horizontal direction perpendicular to the circle (F=mrw ) and gravitational force in the vertical (F=mg due to such a small distance). If you physically propelled it instead of letting go, would this just add a horizontal force parallel to the circle, so that you just resolve the two with pythagoras? Or would you have to use some other calculation to resolve the net horizontal force? I think I'm right in thinking the vertical force would remain constant though. | [
"The moment you let go of it, there is no centripetal force on the ball anymore. That was from you holding it the circular path. So from a top-down view (and neglecting drag), there are no longer any forces on the ball. It continues moving in a straight line at a tangent to where you released it.",
"If you throw ... | [
"Would I be right to think the two horizontal velocity vectors are perpendicular to one another? Assuming the ball was thrown straight forward in the direction I was facing. So the resultant velocity would be a",
" + b",
" =c",
" where a is the tangential velocity and b is the extra velocity from throwing. "
... | [
"That depends in which direction you are throwing the ball, I'm not sure you've specified this anywhere. You say straight forward in the direction you are facing, but which direction are you facing?"
] |
[
"Would it be possible/of any benefit to paint the inside of a swimming pool in a super hydrophobic coating?"
] | [
false
] | I realise it's possible, but perhaps wildly impractical? Would the water behave differently to the point where you wouldn't want it for your backyard pool? If not, could there perhaps be benefits in such a treatment towards limiting the growth of algae or something similar? Thanks in advance, Science! | [
"Superhydrophobic coatings are indeed useful for preventing biofilm formation in situations where you can't use chlorine, such as food processing, bioreactor fermentation, and high purity chemical synthesis."
] | [
"Would coating the hull of a boat with hydrophobic material have any kind of impact on the boat?"
] | [
"It could certainly be done, the cost would be large but not unreasonably so. The observed effects would be minor curiosities, consisting mostly of bubbles sticking very tenaciously to the walls (the walls would wet eventually as they were touched, or just due to the large pressures in deeper parts of the pool). Ab... |
[
"Would we ever be able to interact with alternate dimensions/universes according to the theory of Multiverse?"
] | [
false
] | According to the Theory of Multiverse, there exists an infinite amounts of alternate scenarios in an infinite amount of different universes. Some people like to think of this as "Well, at least I got in some other universe", but I think it's scary because if we interact with these other universes, how do we know we're remaining in one universe and some super-civilization isn't doing multi-universal experiments on humans with wormholes, etc. beaming us to universes extremely similar to ours (but of course unnoticed to the subject). Basically the question is not whether we can, but if it is to interact with these other universes/dimensions? | [
"According to the Theory of Multiverse, there exists an infinite amounts of alternate scenarios in an infinite amount of different universes.",
"There is no \"Theory of Multiverse\". There are several things that are occasionally ",
" that, but nothing to which the term can properly apply. For details on the mo... | [
"I don't think it's by definition. ",
"http://arxiv.org/abs/quant-ph/9510007"
] | [
"Actually, thinking about it a bit, I suppose it has to be that way. There's no way the branches could ",
" decohere."
] |
[
"Is there an evolutionary trait that causes there to be a low percentage of natural leaders compared to those that follow?"
] | [
false
] | I'm just curious as I can't imagine a world where everyone was a leader or a follower. It always seems like there is a natural flow to society with those who lead and those who fall in behind. Is there any reasoning for why this is? Evolutionary reasons or situational reasons? | [
"Because an extraordinary trait is defined by the fact that it is not average.",
"I do not agree with you, that some people are born leaders or something like that, but the above statement is true nonetheless. "
] | [
"It is impossible to prove or disprove conjectures like this.",
"However, statistically, by definition the majority of people cannot be leaders."
] | [
"I think it's more that the worse leaders fail to become leaders, and thus accept follower status (or enter a parallel society)"
] |
[
"Do organelles in animal cells, as well as their number and function, differ from species to species?"
] | [
false
] | null | [
"Hi lc412 thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the following... | [
"I'm on mobile, how do I add a flair on Alien Blue?"
] | [
"Read the message you just responded to"
] |
[
"Can you have concussive force in space?"
] | [
false
] | For example, if an explosion takes place say 20 meters from me on Earth that would cause massive internal trauma due to concussive force, will the effect be the same in the vaccuum of space? Not counting heat/shrapnel of course. | [
"Not likely. What you're talking about is damage from the shockwave that propagates through the atmosphere after the explosion. Without an atmosphere, there's nothing to propagate the shock. You may be hit directly with the expanding gas from the explosion, but this will be very weak in most situations - the damage... | [
"So where does that energy go instead?"
] | [
"The mechanisms can be somewhat different, but explosions can be very damaging in space.",
"Rather than a blast, what you get is more an intense pulse of electromagnetic radiation - heat and light. When it hits an target, the radiation pulse vaporises the surface of the target. This then can produce a destructive... |
[
"If the ratio of the modulus of elasticity to density of aluminum and steel are so similar, what goes in to the decision to use one over the other?"
] | [
false
] | First, I will need to back up the title. I'm going to use numbers based on 4130 and 7075, because they are both relatively common high-strength alloys. Modulus of elasticity = 205 GPa, Density=7830kg/m ratio: 2.68*10 m / s (I don't know what this unit is. Keeping it to show calculations are consistent with each other) Modulus of elasticity = 71 GPa, Density = 2823kg/m ratio: 2.52*10 m / s Wouldn't this mean that a structural member made out of 4130 would actually be lighter than one from 7075 for the same stiffness? Obviously I'm missing something here, because the folks building airplanes didn't just pick aluminum because they felt like it. One thing that occurred to me when thinking about bike tubes is that the aluminum tube will be thicker than the steel, possibly making it more difficult to dent. Is that it? Edit: if this is bogus just let me know. I'm really trying to figure this out. | [
"For airplanes Aluminium is easier to work with, because sheets of the right strength are thick enough. Steel sheets of sufficient thickness to have sufficient strength would be so thin that they are difficult to work with (plus there would probably be quit a lot of bending involved).",
"For tubes, the stiffness ... | [
"There are a couple of factors at work here. Other properties, such as tensile strength and various thermal properties are a major consideration when selecting materials for structures in airplanes & similar things. ",
"As you point out, though, for similar stiffness or strength, an aluminum member will be thicke... | [
"So. Coming from a background in Materials Science, this is a great question. ",
"Many factors go into selecting a material, and they change based on the application. They can include: ",
"Mechanically:\nDensity, Modulus (tensile, bulk, etc), specific modulus (modulus per density), shear strength, tensile/com... |
[
"Question on Relativity"
] | [
false
] | I've got a bit stuck on this relativity question: How fast would you have to travel to get from the Earth to the Sun in one minute, assumiong the Earth is 8 light minutes from the Sun. I've been thinking about this for the last couple of days and just can't seem to get my head around it. | [
"How fast would you have to travel to get from the Earth to the Sun in one minute, assumiong the Earth is 8 light minutes from the Sun.",
"You would need to travel at 0.9923 times the speed of light. Of course, you will only reach the sun in 1 minute according to your watch. The people on Earth will see you movin... | [
"Thanks, would you be able to show me how you worked this out?"
] | [
"It seems to me you just have to solve the equation",
"(d/v)(1/gamma)=60 s",
"Where gamma is the Lorentz factor.",
"I get 99.2% the speed of light."
] |
[
"Do educational facilities ever BUY cadavers for educational purposes, or do they rely 100% on people to donate their bodies to science?"
] | [
false
] | If they do, in what kinds of circumstances does that happen, and what on earth does the facility pay the family? | [
"At universities near me the cadavers are essentially borrowed/rented, and are always donated, never bought. Universities can have them for four years before all remains are returned and cremated. Only in very special circumstances can body parts be kept as a permanent specimen."
] | [
"So, things like rare growths in the brain or the like. Changes in physiology due to different diseases. Specimens that haven't been seen before.\nOther universities might have more freedom, but ours are quite respectful by ensuring the body is complete when cremated."
] | [
"So I have a pretty neat little fact regarding my universities bone collection. Our medical school is fairly old (going back to the 50s) and at the time that they were looking to expand their bone collection for anatomy education, the go-to route was to buy them from india. However, I dont know what the legal reaso... |
[
"List of 26 things that did \"not make sense\" 4-8 years ago according to NewScientist. Current status?"
] | [
false
] | null | [
"I'm not sure about any of the others off the top of my head, but I know that the 'Bloop' has been considered solved. The answer: ",
"ice quakes",
"."
] | [
"The bit about hybrid origin of species.....it's well known that new species can form from hybrids between fairly closely related groups (think two species in the same genera, and you'll get the right idea). There's a much more controversial idea that in some cases the weird shifts between larval and adult forms ... | [
"Actually Morgellon's disease was investigated by the CDC and the ",
"results were published last year",
". The disease is a poorly characterized constellation of symptoms including formications (feelings of insects crawling under the skin), skin symptoms including fibers growing from the skin, and some systemi... |
[
"Why does wasabi have a really strong and spicy taste that lasts for a small amount of time compared to chillies which last for a long amount of time?"
] | [
false
] | I recently felt this when I put too much wasabi on my sushi, it was spicy for about 30 seconds but then the sensation went away. | [
"Wasabi, as with mustard and horseradish, has enzymes that break down compounds called glucosinolates that are present in these plants. The reaction produces isothiocynates, which are the 'hot' compounds you notice when eating those. The glucosinolates and the enzymes producing them are water-soluble, so drinking w... | [
"Chilies belong to the genus Capsicum, and get their hotness from a molecule called capsaicin and it's derivatives.",
"Wasabi on the other hand gets its hotness from thiocyanates.",
"The thiocyanates found in wasabi are rather small molecules and therefore quite volatile, which is why you quite often feel the b... | [
"It is the case that capsaicins have a higher binding affinity to the TRPV1 receptor than the isothiocynates. Oil and water solubility are really neither here nor there."
] |
[
"Were we taught to smile when we're happy or is do we smile for natural reasons? As in, what makes us smile?"
] | [
false
] | null | [
"While it's a combination of genetic and societal influences, smiling is largely thought of as a natural, innate response. We can observe smiling in blind infants (Freedman, 1964). If blind infants, who are unable to witness anyone smiling at all, smile when exposed to happy environments, we might be able to infe... | [
"From everything that I know, smiling is an innate external response to internal feelings of joy. I believe this is determined by babies smiling very early in life, and the fact that blind people smile naturally, even without a frame of reference.",
"http://www.livescience.com/5254-smiles-innate-learned.html"
] | [
"Smiling is also universal across all cultures, which is unlikely in a learned behavior."
] |
[
"Is there a human speed limit?"
] | [
false
] | I always hear about people breaking records for non-powered travel (like running, swimming, etc.). Is there a limit to how fast a human can run? If so, what is it? | [
"The limiting factor is the amount of force that muscles can apply over a given time. Going only off of this factor, the theoretical absolute maximum speed is around 19.3 ms",
" or 43 miles per hour. This is obviously for short distances; for longer distances, cardiovascular and respiratory factors become the lim... | [
"Already been an issue. A guy with no feet but leg extentions was not allowed to race in a normal race because it was actually an advantage and not a disadvantage. "
] | [
"It's generally pretty easy to tell what is and isn't human because you don't run into boundary cases often. But the fastest possible human is a boundary case by definition. They are such that any change makes them either slower or nonhuman. If I started with a human, and then slowly changed them until I got a spac... |
[
"According to metric expansion, is there \"new\" space being created between galaxies?"
] | [
false
] | If space is expanding between galaxies, what are the properties of that space? When the distances increase, is space being "stretched" or is there "new" space being created in between them? As I understand it, the galaxies themselves aren't moving in the traditional sense of the word. Perhaps my question isn't quite clear, but I guess what I'm asking is, if there were a certain number of planck lengths between 2 galaxies, would that number be increasing as space expands, or do the lengths themselves get longer? If "new" space is being created, what is the process for that/where does it come from? | [
"Space isn't really a \"thing\" that is being stretched. All that is happening is the distance between points is getting bigger.",
"Space is also not divided into a number of planck-length \"pixels\". The planck length is important, and you do get some interesting physics happening below that length scale, but it... | [
"But if it isn't a \"thing\", then what is the mechanism for the expansion? Space itself is what's expanding correct? As I've understood this concept, the galaxies aren't \"moving\" through space, but the space between them is expanding in all directions.",
"\"Space itself\" isn't really anything. When we say thi... | [
"Sorry for the long post, but your questions are deep and have complex answers.",
"Based on your explanation, the\"points\" in space or Planck lengths are not the same as \"space itself\". Would that be correct?",
"Okay, I gotta dispel one misconception you seem to have, before I can explain: Planck lengths ar... |
[
"Is it true that a shooter absorbs an equal amount of force into his body as is being projected in the bullet?"
] | [
false
] | null | [
"There is a lot of confusion in the answers here about pressure, force, energy, and momentum. Working backwards through that list:",
"Momentum is conserved, so both the shooter and the object hit by the bullet absorb the same amount of momentum. That means if you were floating in space and fired a bullet into som... | [
"Not exactly. Some of it does go into the shooters body, but some is also expended in muzzle climb. In the case of automatic and semi-automatic firearms, some is redirected to operate the reloading mechanism. There are also stock modifications that absorb recoil as well.",
"I'm going to guess that you're getti... | [
"Worth pointing out that your first claim is only true if the bullet stays within the body of the person shot. A more powerful shot might penetrate all the way through and transfer only some fraction of its energy and momentum to the victim, before exiting on the other side. This can of course still be quite lethal... |
[
"What is the largest object that Humans can create/fashion that will have the exact same molecular makeup?"
] | [
false
] | null | [
"It's an entropy thing. An exactly perfect crystal has only one arrangement. It would be like flipping Avogadro's number worth of coins and getting all heads. Even if the coins are really unfair (analogous to a very low energy crystal state) some of them will come up tails."
] | [
"All crystals (graphene included) above 0 K have some defects in the atomic arrangement and because any of reasonable size (including those in the image you linked) are made of so many atoms, it is very unlikely that any two similar ones would have exactly the same number. So for anything large enough to be conside... | [
"What do you mean molecular layout? Do you mean ",
"single crystal",
"?"
] |
[
"What is stopping light from being projected onto the moon from earth?"
] | [
false
] | Specifically, is the ability to do this beyond us right now? Do we not have bright enough or focused enough lights? Is it possible to just colour the moon with light, even if there is no discernible image there? I'd think if it was possible to do it well, we'd be seeing a battle for corporate logos on the moon, so I guess it isn't. | [
"Dammit I was about to post the same xkcd. ",
"Of course, we do shine lights on the moon, its just we don't get much light back. ",
"The only remaining continually operated part of the Apollo programme is a long running experiment that fires laser light at a reflector dish put their by astronauts and times the ... | [
"Dammit I was about to post the same xkcd. ",
"Of course, we do shine lights on the moon, its just we don't get much light back. ",
"The only remaining continually operated part of the Apollo programme is a long running experiment that fires laser light at a reflector dish put their by astronauts and times the ... | [
"Link to the Apache Point Observatory Lunar Laser-ranging Operations (APOLLO) website",
"They shoot laser pulses at the retroreflectors and get maybe 1 in a quadrillion photons back (and that's with the collecting area of a 3.5 meter primary mirror, as opposed to a human pupil of less than a centimeter). It would... |
[
"Do plants have immune systems?"
] | [
false
] | [deleted] | [
"Yes. Typically called \"defenses\" more than an immune system though but they react to pathogens and external threats;",
"http://en.wikipedia.org/wiki/Innate_immune_system#Host_defense_in_plants"
] | [
"Plants have a two-tiered immune system in which the first tier recognizes pathogen associated molecular patterns (PAMPs) in a way analogous to the mammalian innate immune response, and the second tier recognizes pathogen-specific effectors once they have entered the plant cell. The first line of defense will elic... | [
"An immune system as we humans are used to requires white blood cells, so this is correct."
] |
[
"Since MERS has a high fatality rate (36%) and only about 2500 confirmed cases over a span of eight years, why hasn't it been contained (and basically eliminated) like SARS-CoV-1 was?"
] | [
false
] | null | [
"Unlike SARS (and SARS-CoV-2), MERS transmits very poorly in humans, usually only a few steps along a transmission chain, and it has not become established in human populations. All MERS transmission chains start with infection of a human by a camel. So the only way to eliminate MERS would be to eliminate it from ... | [
"Nothing identical to (or nearly identical to) to SARS-CoV-1 has been found in bats, but there’s a family of quite similar ones that includes SARS-CoV-2 relatives too. For example ",
"Close relative of SARS virus found in Chinese bats",
"Divergence of nCoV-2019 to closest non-human relative",
"If that makes y... | [
"But why would anyone listen to a virologist anyway.",
"Well they might have This Week in Virology on their podcast feed..."
] |
[
"Protein synthesis in chemistry?"
] | [
false
] | If a certain protein is composed of a sequence of amino acids, can you simply combine said amino acids to create that protein? Is mixing amino acids a plausible way of creating a protein? | [
"You can, up to a point! though it’s a bit more complex than just mixing amino acids together. The standard method of synthesising short peptide sequences - ",
"SPPS",
" - works by fixing an amino acid to a resin surface, then successively adding the amino acids you want until the desired sequence is made. This... | [
"I worked in a lab that does this! It is kind of possible. ",
"Heres the general process:",
"First of all, you use amino acids that have been modified to have protected side chains and differently protected amino groups. The C terminal amino acid is bound to a resin as a solid so you can do wash steps between e... | [
"That's wrong. ",
"Solid phase peptide synthesis",
" is doable, albeit inefficient."
] |
[
"What gasses are inside a cavitation bubble? How does gasses from a liquid end up being gathered into a bubble format?"
] | [
false
] | What gasses are inside a cavitation bubble? How does gasses from a liquid end up being gathered into a bubble format? I'm curious if it is possible to purposefully create cavitation bubbles and then harvest them into tanks so that you could extract air out of water. | [
"Cavitation bubbles are made of the same substance as the surrounding fluid. That is, if you're generating them in the ocean, they'll be made out of water vapor.",
"You know how water boils at a lower temperature at higher altitudes, so there are often different directions for stuff at sea level vs 10,000 ft? W... | [
"So no air gasses inside the cavitation bubble?"
] | [
"\"Air gasses\" (dissolved oxygen, nitrogen, etc.) are at the same concentration inside the bubble as outside the bubble."
] |
[
"If you sum these number patterns (picture in the description) with their palindrome number, the result will always be 1110. Why is that?"
] | [
false
] | I was bored in math class, so I started typing some random numbers in my calculator. Then I realized that these numbers in this summed with the palindrome of that same number always results in 1110. Is there any reason for it to happen, or is it just coincidence? These are the possible results: 258+852=1110 456+654=1110 159+951=1110 357+753=1110 | [
"Two numbers across from each other on a calculator or phone grid will always sum to 10 because of the way they're laid out (and 5 is \"across\" from itself). By choosing only numbers that go through the center of the grid, you're making sure you only choose numbers that are across from each other. When you take th... | [
"The across-5-ness is important because the numbers on either side are the same distance from five but in opposite directions",
"4 = 5-1, 6 = 5+1, etc.",
"so the distances cancel and its 5's all the way down. That'll be true for any odd-sized grid, and any line you pick. For example, consider a 5 by 5 grid:",
... | [
"Your number is A x 100 + 5 x 10 + (10-A) x 1.",
"Its palindrome is (10-A) x 100 + 5 x 10 + A x 1.",
"When you add these, you get (10-A + A) x 100 + (5 + 5) x 10 + (10-A + A) x 1, which is 10 x 100 + 10 x 10 + 10 x 1, or 1110, as you observed."
] |
[
"What happens if I use my 30-day disposable contacts beyond one month?"
] | [
false
] | null | [
"This is a medical question or sorts...",
"But the FDA rates contacts at their \"safe to wear\" period. Beyond that, there is a increased risk of damaging your eyes due to any number of factors. ",
"The truth is that there's an organization that extensively tests these things for a reason: wear them for their p... | [
"I asked my optometrist about this. She said the contacts deform over time and you'll lose your acuity slowly for the lense. "
] | [
"You have an increased risk of eye infection if you wear them for longer. Additionally, as they age, the lenses can crack or rip slightly, which isn't always obvious to the naked eye, but causes quite a bit of discomfort. Or, as they dry out (particularly if you sleep in them), they can actually cut your eye."
] |
[
"Why can cracking a joint release muscle tension?"
] | [
false
] | Regularly, I'll have muscle tension and/or pain in my back, shoulder, wrist, etc that seem to be resolved after cracking an affected joint. Just stretching the affected area isn't enough in these cases. Knowing that, fundamentally, cracking a joint is just creating a cavity between the bones (and hence stretching the muscles and ligaments), it's not clear to me why this should be. | [
"To be straight, there is no answer backed with scientific evidence to answer this question of yours but there are many theories.",
"I am a D.O. (osteopathic) medical student. One technique we do is called HVLA and involves \"popping\" or as we say gapping a restricted joint. The current running theory is that re... | [
"Most of the studies I've read mention very little about enorphins. It's plausible though."
] | [
"Im no doctor, but doesnt cracking a joint make your brain think there was severe trauma at that point and thus release endorphins? Wouldn't that be the part that makes it feel like it \"releases muscle tension\"?"
] |
[
"Is the usable mathematics a limiting factor for study of Physics?"
] | [
false
] | This is a very long post with a lot of questions: I recall a quote by Einstein saying that he could not proceed further after a point in GR with the general mathematical tools until he was able to use tensors in it. Is it that the more simpler concepts were too inadequate, or was it that it was almost unworkable with those simpler mathematical techniques? Looking at QM, Heisenberg initially worked with Matrices and Schrodinger waves, with the latter method simpler and more intuitive, but both later proved to be equivalent in their approach. Fermat claimed a very elegant proof of his last theorem, but didn't it take mathematics which were developed only recently(20th century) to prove it? And the proof is not elegant(100+ pages). Did the mathematics limit our idea or was it that only Fermat could prove it elegantly? My question being, would future theories rely more on using the most sophisticated mathematical ideas to create a complete model or is that the model be explained with more simpler tools , pointing towards an "equivalence"? And since mathematics is voluminous, would learning very complex models to be applied in physics be justified? Any additional info would be helpful too. | [
"From the level of quantum mechanics that I have studied, almost every single form of Schrodinger's equation can be solved using perturbation theory. ",
"That's because in courses they only present you with problems that have known solutions, and are amenable to approximation methods like perturbation theory. By... | [
"I'll leave most of your questions to people more knowledgeable in physics, but I'd like to address the part about Fermat's last theorem. It is generally believed that Fermat didn't have a correct proof; the only known proof requires methods far beyond what was known in Fermat's time, and in fact involves the study... | [
"Possibly.",
"While I haven't studied General Relativity in depth and can't speak to that particular example, in general I can confirm that physics periodically relies on advancements in mathematics to advance itself.",
"The thing is that advancements in physics are largely unpredictable. We don't know what we'... |
[
"Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...". Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists. Please only answer a posted question if you are an expert in the field. . In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for . If you would like to become a member of the AskScience panel, . Past AskAnythingWednesday posts . Ask away! | [
"Taiwan and Costa Rica have an audit branch of government in addition to the three classic branches. What does it do and why do they have it?"
] | [
"Are there any political systems in the world where the judiciary has oversight over or is otherwise involved in the budgeting process? If so, are those systems successful?"
] | [
"Ashkenazi Jews have traditionally held finance jobs in parts of Europe and America for the last 800 years or so. They have acquired a money-conscious stereotype as a result. I remember reading somewhere that other cultures have their own versions of the stereotypical money-conscious demographic. Does anyone know w... |
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