title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"What was the purpose of the large, projecting ischium hip bone in some dinosaurs?"
] | [
false
] | I've been looking at some cool analyses of dinosaur anatomy recently, and I've noticed how out-stretched and fragile-looking the hip bones of both are. It seems like they'd be prone to injury, would make laying down difficult, and I'm not sure what purpose they served. You can see the hip's strange jutting very clearly... | [
"The pubis and ischium are components in, to the best of my knowledge, the pelvic structure of every creature that possesses such an apparatus. In ",
"this",
" image of the human pelvis, the pubic bone (pubis)and ischium are marked by the numbers 4 and 3, respectively. As you can see, the same structures exist,... | [
"Sure did. Thanks!"
] | [
"When laying down, the weight of the animal would mostly transferred to the abdomen, not the pelvis",
"Why is that?"
] |
[
"Do we update latitudes and longitudes to account for plate tectonics?"
] | [
false
] | I just watched a documentary about the Yellowstone hotspot, and it said that the US in that region is moving to the SW at about one inch/year. That would be about 1m in 40 years, which is enough to mess up navigation. How do we account for that? | [
"Yes and no.",
"In the old days, the official description of a property was ",
"metes and bounds",
" text that referenced physical landmarks, e.g. \"the edge of the property starts at the stone marker at the corner of Main St, continues for 421 feet northwest to the stone wall, then north-northwest...\" These... | [
"We account for it by updating our sets of digital data that feed the GIS portion of our map systems.",
"Realistically, we are talking about a change somewhere in the 5th decimal place of the degree coordinates over 100 years, so it wouldn't affect or be noticed by you unless updating that data is your job."
] | [
"Technically no, the written document specifies those exact lat/long points, even if the landmass shifts. Practically, the border just moves with the tectonics, the change is so small that it doesn’t really matter."
] |
[
"Why do i get hungry and then, without eating, it goes away?"
] | [
false
] | Did my body just say "uuugh, you know what, fuck it, you're right: Don't feed yourself! You're not hungry anymore, because i just started eating stored fats" How is it possible to be hungry for an hour and then it just disappear for the next 3-4 hrs? | [
"Gluconeogenesis",
" is your bodies ability to convert ",
"protein into glucose",
". The process is inactive while insulin in the blood stream is present in high enough levels.",
"There is a period of time where you have ",
"low blood sugar",
", as insulin released from eating is ",
"balancing",
" o... | [
"A lot of twitch streamers do this. Drinking soda slowly all day instead of eating. You still crave protein and a real meal towards the end of the day. But sipping soda is great to stave off hunger pangs.",
"Survival mre's are packed with dextrose tablets, essentially flavored sugar cubes. Because they work so we... | [
"That's pretty fascinating. At work I used to get really hungry mid shift but be too busy to eat. I found that drinking some coke was an easy way to fend off hunger in a pinch. Guess it makes sense given its insane sugar content."
] |
[
"Could a planet be bigger than its own star in terms of mass?"
] | [
false
] | null | [
"No, it'd be a star."
] | [
"It's unlikely, when a body has around 30-70 times the mass of Jupiter it begins to undergo fusion and turns into a star. A planet more massive than a star wouldn't be able to support it's own mass against gravity. "
] | [
"rocky planets cant get larger than 14 Earths without becoming brown dwarfs or collapsing. ",
"the largest rocky planet we know of is about 5 Earths (mass) still a few times smaller than any star."
] |
[
"An ancestor of plants and animals?"
] | [
false
] | null | [
"Hi s-o-lACE 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 follow... | [
"Hi s-o-lACE 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 follow... | [
"Hi s-o-lACE 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 follow... |
[
"Why do we have growth spurts? Wouldn’t it make more evolutionary sense to spread the physical changes evenly over the years?"
] | [
false
] | What's the advantage of growth spurts over gradual and even changes. | [
"On the contrary! Babies also have growth spurts but major growth spurts happen around the early teen years of both boys and girls. The reason behind this is that the body is getting ready (during the major ones) for sexual maturation (pubic hair, menstruation, sex organ development). ",
"The most important thing... | [
"In addition to other thoughts, growth and development are expensive processes. You're familiar with the idea of stunted growth (in plants as well as animals). This is often caused by the body not being able to obtain enough of the necessary nutrients to grow properly. So, I would conjecture that some of the time b... | [
"It makes more evolutionary sense for us to grow to maturity as fast as anatomically possible to \"hunt for our food,\" self persevere, and reproduce. Spreading out physical changes over the course of our life increases the chance of us dieing as \"man babies\" before we get a chance to have offspring."
] |
[
"What experiments show that quantum entangled particles must communicate via spooky action at a distance?"
] | [
false
] | So let's say I have two entangled electrons, and I know that one must be up spin, and the other must be down spin. Why do we know the particles stay in a superstates when they're separated? What experiments have we done which says that the particles hadn't already chosen states before they were separated? A friend poin... | [
"Put simply, Bell's theorem says \"Let's assume that there is some 'real' thing determining probabilities, even if we can't measure it. Let's also assume that detectors' configuration can only be communicated classically.\" And we observe that the predictions of those two ",
" assumptions do not match the data we... | [
"It's Bell's theorem, so I'll just explain that.",
"Suppose you're doing your electron experiment, only you rotate one of your detectors so that it's pointing in the opposite direction. Now, if you measure both electrons, the detectors will always say that the electrons point in the same direction. Of course, the... | [
"Thanks!"
] |
[
"Is there any benefit to a grass roof on a house?"
] | [
false
] | i saw a grass roof on a house today and I was curious about wether or not it was beneficial or just for looks. | [
"My university is currently doing a study on green roofs.",
". The site has some of the benefits of green roofs as well as publications which go more in depth."
] | [
"If deployed on a large scale, green roofs could mitigate the urban heat island effect. They also act as good insulation."
] | [
"The considerations about water usage are a great point, and it's worth mentioning that simply having white roofs can also lessen the urban heat island effect, in areas where water security or aesthetic concerns make green roofs unfeasible."
] |
[
"In what context would kJ mol−1 be useful for light?"
] | [
false
] | I was browsing the and was really confused by the table that gave first the energy in eV, which I am familiar with, and then in (kJ mol−1). I assume this is referring to the energy of one mole of photons, given in kJ? Why would this be useful? I'm just not sure of any context where I would even come across this. Thanks... | [
"Sometimes I use the approximation 100 kJ / mol ~ 1 eV / particle as a quick back-of-the-envelope type comparison between bond energies and photon energies."
] | [
"One example - by preparing molecules with well defined translational energy in molecular beams, and in tandem, well defined rotational and vibrational states with lasers, it's possible to explore bond- and mode-selective chemistry at the gas-solid interface. Here's an example of ",
"methane dissociation over Ni(... | [
"The following approximation is one of my favourites in physics:\nE(eV) = 1240 / lambda(nm)",
"If you have the wavelength of light in nanometers, you can relate it to its energy in eV with this simple approximation. It's quite good for back-of-the-envelope calculations."
] |
[
"Does one burn more calories in hot or cold temperatures?"
] | [
false
] | I've heard two explanations - In cold temperatures, you need to burn more calories to maintain your core body temperature. (Also, that old joke about the ice cream and beer diet) In hot temperatures, your metabolism is at a higher baseline rate and you are therefore burning more calories. I never bothered to check eith... | [
"How hot or cold are we talking?",
"In the cold your body is using energy to keep you warm and in the heat your body is using energy to keep you cool so I guess the question is which one is more efficient. ",
"The basal metabolic rate increases slightly in colder climates, and Dr. Askew said there might be a ve... | [
"question along the same lines: can you increase your calorie usage by drinking all your water ice-cold? a quick calculation says 1 gallon of ice-cold water requires ~140 Kcal to be raised to body temperature. ",
"so if you drank a gallon of ice water throughout the day, could you count that as negative calories... | [
"Let's say a low of 0C to a high of 40C",
"It seems like you burn more calories at rest in cold temperatures than warm temperatures. What about during exercise? Does one burn more calories on a treadmill at 0C or at 40C?"
] |
[
"How did dyslexia manifest itself before the invention of written language? Or, alternatively, was dyslexia developed due to written language?"
] | [
false
] | null | [
"Difficulty distinguishing left from right, difficulty with directionality, and delayed speech onset would all manifest with or without written language, but they would not be sufficient for a diagnosis.",
"http://pediatrics.aappublications.org/content/127/3/e818",
"Because of the main symptom of dyslexia being... | [
"As a medical diagnosis, dyslexia denotes particular issues with reading, writing, separating and understanding spoken words, vocalizing words and/or comprehending spoken/written sentences (the first two are the primary criteria, the rest may or may not be present).",
"So it's pretty unlikely that an animal would... | [
"Does this mean animals can be dyslexic too? How can we know whether animals are dyslexic or not? I mean can we design an experiment which can have an outcome: "
] |
[
"Why does the LHC run at center of mass energies of around 14 TeV when most threshold energies for particle production are in the GeV range?"
] | [
false
] | null | [
"The threshold energy is the ",
" amount of energy you need to produce a given particle. But that doesn't mean you'll get a good production rate at that energy (you probably won't)."
] | [
"The center of mass energy is essentially twice the energy of each beam in the lab frame, since they're colliding."
] | [
"A lot of production cross sections in hadron collisions increase with energy, so higher energy means higher statistics. Plus it makes more parameter space of BSM theories able to be excluded."
] |
[
"If I setup a funnel to catch the wind, would it speed up the wind's speed? If so, to what degree and what is the maximum of this?"
] | [
false
] | null | [
"Ignoring some confounding complexities, the conservation of volume alone yields a very simple relation: A x v = constant, where A is the cross-sectional area of a pipe and v is the velocity of the fluid. So if you restrict the cross-sectional area by half you double the speed of air flow, for example."
] | [
"It's fine up to a point. Air is generally considered incompressible up to about .3 mach, or 102 m/s (228mph) at STP. ",
"Assuming a reasonable 5 m/s windspeed, the device could reduce the flow area by about 20x. For an outlet of 1 meter the inlet would be about 4.5 meters. ",
"Edit: You can definitely go beyo... | [
"Im not sure the conservation of volume is useful in a compressible fluid. ",
"Confounders are large, both on the inlet and outlet and depend critically on the size and shape of the inlets and the speed of gas. . As the gas gets compressed on the inlet as it goes in it will tend to push away incoming air, meaning... |
[
"How does the retina differentiate the three primary colors?"
] | [
false
] | I know we have 3 types of cone cells that have different photopigments in them, but, if I remember correctly, they all use the same neurotransmitter to pass the signal further in the retina, so how does the retinal ganglion cells differentiate where a signal is coming from? | [
"Neurotransmitters only work in the very tight space of an individual synapse. If a particular axon expresses a particular neurotransmitter, the signal will only be received by the dendrites of the cell to which they are connected. It is the separation of pathways that allows the different colors to be differentiat... | [
"so, essentially the eye is wired so that only certain signals end up at certain ganglion cells?"
] | [
"Yes. There is very little cross talk between synapses.",
"\nFun fact: The retinal ganglion cells are actually located ",
" of the photoreceptor cells. "
] |
[
"Is there a way to generate an MD5 hash with a pen and paper?"
] | [
false
] | null | [
"Sure, you can follow along and execute the common implementations by hand. You're going to regret your decision very quickly and give up but it can be done.",
"If you're looking for an easy way to compute the hash by hand then you're out of luck. Hashing isn't like CRC or parity where a human has a chance of w... | [
"Consider this: if we don't know how to do something, how can we direct a computer to do it?",
"In general, there is a \"pen and paper\" way to do everything a computer does. Algorithms can be carried out by hand, but doing so can and does turn into an arduous, time consuming task. This is why we use computers... | [
"here is the ",
"pseudocode",
" (from wikipedia)",
"You could do each instruction by hand... but yes, it might take you a while."
] |
[
"How thick does a piece of glass have to be before light cannot travel through it?"
] | [
false
] | I was looking at a window today, and realised that the window must block some light, so I was wondering how thick a piece of glass would have to be before no light would make it from one end to the other. | [
"The best (clearest) glass is the high-quality fused silica inside the optical fibers used for telecommunications. These are amazingly clear -- they attenuate light (at 1.5 micron wavelength -- a wavelength the human eye can't see) at a rate of 0.2 dB/km. At that rate, considering a reasonably bright light (1 mW)... | [
"That would depend on the kind of glass. Light traveling through glass will be absorbed in some percentage per unit of distance, this percentage is called transmittance. Based on the transmittance, it will fall off via ",
" an exponential decay curve, thank you IndustriousMadman.",
"The kind of transmittance we... | [
"Basically yes, optical amplifiers are inserted inline in the massive fiber rolls on the cable laying ships. ",
"http://en.wikipedia.org/wiki/Optical_amplifier"
] |
[
"How did scientists during the 1918-1919 Influenza Pandemic know what a virus was?"
] | [
false
] | Medical science had come a long way throughout the latter half of the 19th century, let alone up to WWI. The germ theory was generally accepted, and scientists were mostly on the same page about how disease outbreaks started with microorganisms. They could even observe and describe the shape of certain bacteria with mi... | [
"In the late 19th century they produced a filter, called the Chamberland filter, able to filter out bacteria. This led to the discovery of both viruses and bacterial toxins in the late 19th century. Scientists had determined that viruses (like tobacco mosaic virus) could remain infectious even when filtered throu... | [
"Because you don't need to know the causative agent of an infectious disease to observe how it spreads.",
"John Snow traced the London cholera epidemic to the Broad Street pump by determining that all of the people suffering from cholera had consumed water that originated at that one pump. He had no idea that ch... | [
"Indeed, and the tobacco mosaic virus was only discovered 30 years before the Spanish Flu. ",
"Oddly the first DNA extracted from a virus was 30 years prior to determining what exactly a virus might have been. ",
"They didn't even discover DNA's actual function for another 80 years, they managed to extract ... |
[
"How do I make gallium crystals?"
] | [
false
] | Hi there. I just bought some gallium for my dad's birthday. He has everything he needs and money to buy most things... but is practical and doesn't buy "fun" things for himself. I thought gallium looked cool so I decided to buy some. Now I am looking for fun things to do beyond the initial novelty of it melting in your... | [
"Not acutely. As in.. you won't suffer any life threatening effects while handling it. However, there have been mixed studies about minor effects, such as skin irritations.",
"Also, don't let gallium touch other metal structures, such as aluminum pans- the gallium will diffuse into the metal and cause the pan t... | [
"Quite the opposite, gallium will diffuse into the metal and cause it to become extremely malleable."
] | [
"If you have sufficiently pure gallium (I believe the video said 99.998% pure), you should be able to grow crystals by cooling the gallium slowly (such as by placing it in a cool spot in the house) and leaving it completely undisturbed for at least an hour, if not longer."
] |
[
"If photons don't have mass, how do solar sails work?"
] | [
false
] | Sorry if this has been explained here before, I just stumbled across this subreddit (and frontpaged it!). I'm currently under the impression that photons are massless. Which leads me believe that they cannot have momentum. How can they push solar sails through space? | [
"The formula ",
" = ",
" is an approximation which works very well for things moving much slower than the speed of light. ",
"Using the relativistic formula",
"\n",
"² – ",
"²",
"² = (",
"²)²",
"\ngives the momentum of a photon: ",
" = ",
", where ",
" = 2",
"/",
"."
] | [
"I'll do my best.",
" is the total energy of whatever we're talking about, ",
" is its momentum, ",
" is the speed of light, and ",
" is its \"rest mass\", which basically means its mass. ",
" = 0 for a photon, as you correctly said.",
" is called \"the reduced Planck constant\" and it's just a number. ... | [
"Photons don't have mass but they DO have momentum which can push a sail through space."
] |
[
"Does a single solar mass black hole exhibit the same gravity effects as the sun?"
] | [
false
] | I imagine they are similar at the distance we are from our sun. But it also seems like if I got closer, at a certain point, things would be different. Where would that point be? For example, if I'm in a ship, when would I stop experiencing the gravitational effects of a regular star and start experiencing the unique gr... | [
"The exterior metric of a star such as the Sun is identical to that of the corresponding black hole with the same mass. So there is no difference in gravitational physics as long as you are outside the surface of the Sun. This fact is a theorem in GR known as Birkhoff's theorem.",
"The metric is different in the ... | [
"The point is if you don't get closer to the black hole than an original solar radius, it's still the same physics."
] | [
"It does! Well, for the most part. There are a couple of ways in which this isn't quite correct:",
"As you said, there's some distance at which you notice the black hole's... well, black hole-ness. That point is the surface of the Sun. Outside a spherically-symmetric object (like the Sun almost is, more on that i... |
[
"Can I calculate the speed of my train from the angle which rain droplets are sliding down the window?"
] | [
false
] | null | [
"You could, but you would be making alot of assumptions in doing so. The coefficient of friction of the glass, the humidity & density of the air outside, the temperature of the drops, the characteristics of the boundary layer flow on the surface of the train's window, the speed and direction of the wind outside, th... | [
"Not easily, no. ",
"The reason is a train is not perfectly aerodynamic and so there will be turbulence affecting the air around the train. As a result, droplets will move more or less at different positions on the window, as well as when you're going around the inside or outside of a bend or curve. And you also ... | [
"Hi leujohn 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 followi... |
[
"Since black holes evaporate, shouldn't infalling observers never reach the event horizon?"
] | [
false
] | If I understand correctly, there literally can't exist any proper time inside of the event horizon of a black hole because it has to succeed an infinitude of time first elapsing outside of the black hole. Infalling observers are time dilated to an indefinite shear as measured in a sidereal frame of reference. Unlike th... | [
"Time only slows down from the reference point of the outside observer. They would see someone falling in go slower and slower but never cross the horizon.",
"This does not take place in the reference frame of the faller. For them, time passes normally even when inside the horizon.",
"Information about events... | [
"Time only slows down from the reference point of the outside observer. They would see someone falling in go slower and slower but never cross the horizon.",
"This aligns with my understanding. The infalling observer's reference frame shears indefinitely relative to sidereal frames: sidereal observers would view ... | [
"The event horizon does not effect the passage of time (that would only happen as you approach the singularity at the center of the block hole), only information flow. ",
"When in IO1's reference frame, when in any sidereal reference frame, would IO2 cross the horizon?",
"IO1 could calculate when that event ha... |
[
"What properties do ferrous materials have that other metals don't, allowing for the formation of magnets?"
] | [
false
] | null | [
"First, the smallest component of a ferromagnetic material, which can be either an atom or a compound, needs to have unpaired electrons so that it has a nonzero magnetic moment. Second, the interactions between these components need to favor alignment: the potential energy of a pair of atoms most be lower if their ... | [
"It still only affects materials that are paramagnetic, which isn't everything but it more than the relatively few elements that can be permanent magnets at room temperature."
] | [
"It still only affects materials that are paramagnetic, which isn't everything but it more than the relatively few elements that can be permanent magnets at room temperature."
] |
[
"Can we capture the fresh water that's melting from the glaciers due to global warming?"
] | [
false
] | [deleted] | [
"Yes, with a sufficient amount of money you could construct lots of dams in Greenland and Antarctica and capture the melting run off of the glaciers. But why would you do it and is it cost effective? What would you do with all the water? It is too far from croplands to be useful for irrigation. If you construct... | [
"Again, yes, but the amount of water that is melting is massive. Water is also decently heavy. Thus, transporting would be very expensive as mentioned before. The best way would be pipes. But then again, we would need a lot of pipe, miles and miles, and miles of pipeline. Then we have to consider the fact that... | [
"Really great answer, thank you. "
] |
[
"Can you get ptsd (or develop other psychological disorders) from a dream?"
] | [
false
] | It seems extremely traumatic events happen in nightmares for many people; things that, were they to occur in real life, would leave their subjects inescapably scarred. During the dream such events can seem indistinguishably real, so why do we so often suffer no ill effects after? Is there a censoring process that occur... | [
"I think the first thing to address with this question is to state that PTSD is currently classified by a set of symptoms, not by any biological or neurobiological markers. This means that the determination of whether a person does or does not suffer from PTSD oftentimes depends on a healthy dose of clinical judge... | [
"I'll take a stab at this. As to your first question, the best I think anyone can say is \"kinda.\"",
"Think of PTSD as a normal reaction to stressful situations gone haywire. From a biological standpoint, the symptoms produced essentially come from an over-reactive autonomic nervous system. Take a soldier in a w... | [
"This exactly, my lab group works closely with another PTSD study and the methods they use are specifically designed to dissociate the traumatic memories from the emotional response to prevent the memories from triggering the emotional response. It's quite fascinating.",
"This paper: ",
"http://blogs.discoverma... |
[
"The Pirate Bay is satirically claiming they're launching \"Low Orbit Server Stations\". Can anyone comment on feasibility?"
] | [
false
] | [deleted] | [
"It's going to be in LEO, it could be powered just fine by solar."
] | [
"Note that nowadays, a server does not necessarily represent a very big or demanding machine, especially if their objective is to mirror magnet links. 1 GB of storage is far enough for their needs."
] | [
"Your main limiting factor will be battery power. We already have the parts to build all the components of their design. (drones, wireless transmission devices etc) But being able to power them becomes a real drag. Most drones available to the public have flight times under an hour, combine that with the added weig... |
[
"How do cells within organisms signal need for nutrients and energy?"
] | [
false
] | If you want to focus on something specific, humans would work, though animals / plants / other taxa details might also be of interest. The general question is this: how are nutrients, both macro (carbs, lipids, aminos), and micro (vitamins, minerals) allocated among cells and tissues within an organism? Do the tissue... | [
"Hi dred,",
"I want to give you a bit of an easier answer to your question. I am the TA of metabolism CHEM114B at UCSD with an extensive background in pharmacological chemistry.",
"So the simple answer is this, concentrations.",
"Concentrations of various molecules in the body may end up affecting metabolic p... | [
"Correct. mTOR primarily conveys positive energy balance signals into pro-anabolic pathways; that is, it integrates pro-growth signals associated with system-wide energy abundance (such as insulin, GH, IGF) and local, cellular signals of \"plenty\" (such as amino acid abundance, levels of ATP, oxygen availability)... | [
"Sorry for the late reply. It has been a hectic day in lab today. ",
"Yes, mTOR is inside the cell. It responds to the signals derived from your endocrine examples (and others such as leptin), as well as the nutrient levels themselves (amino acid sensing is the best understood example). mTOR functions to integrat... |
[
"Evolutionary Adaptations to the Modern Diet"
] | [
false
] | In regards to human evolutionary adaptations to the modern diet, experts always use the example of western cultures gaining an increased ability to process lactose (via lactase production) beyond adolescence. Yet I’ve never heard of any additional examples of modern diet human adaptations. Can anyone give some exampl... | [
"Not just in Western cultures; Africans, Indians, and Asians have high rates of lactose tolerance as well. Mutations that cause continued lactase production into adulthood have arisen independently four different times, under selective pressure in pastoral societies.",
"Here is a very well-done study that examine... | [
"This one doesn't strictly involve human evolution, but a study found that Japanese people are more likely than others to have intestinal bacteria that can break down complex carbohydrates in seaweed. It's thought that this might help out people who eat a lot of seaweed, since they might be able to derive more ene... | [
"It might not be exactly what you're looking for, but ",
"these people",
" argue that our long lifespan, our fancy brains, and long juvenile periods are all evolutionary responses to dietary changes."
] |
[
"How did they originally calculate what temperature absolute zero would be?"
] | [
false
] | [deleted] | [
"The third law of thermodynamics prevents one from actually obtaining absolute zero. That doesn't stop you from plotting a bunch of points and extrapolating a line down."
] | [
"Take a set quantity of air. Measure the air pressure at various temperatures, like 0 deg, 100 deg, 200 deg. Graph those points. Those data points create a line that intersects zero pressure at a particular super cold temperature. "
] | [
"Is it actually possible? I thought I read somewhere that 0 pressure is impossible. Similar to the concept of matter traveling at the speed of light requiring infinite energy, 0 energy would essentially stop time."
] |
[
"What makes a surface antimicrobial?"
] | [
false
] | You see the signs on things like baby changing tables and play places at McDonald's. But it just looks like plastic. What if anything is different about the surface? | [
"Generally, antimicrobial could mean a variety of different things are at play. The most basic characteristic is that these surfaces have either a chemical or physical feature that inhibits and/or kills bacteria and viruses that come into contact with it. ",
"Some metals are naturally antimicrobial, such as coppe... | [
"Thanks for your response."
] | [
"I didn't think antimicrobial ever meant virus killing, just like antibiotics"
] |
[
"What colour are Neutron stars?"
] | [
false
] | Assuming we have a magic shield that blocks out all non-visible light, and a human eye (human optional) within viewing distance, what colour would a neutron star appear to be? Would there be a shift in spectrum emissions because of gravitational effects? | [
" White. Neutron stars are simply white hot. ",
" Surface temperature of a neutron star is in the neighborhood of 1 million K. This has a peak blackbody spectra around a few nanometers, well below the 400 nm or so cutoff of the visible spectra. The visible spectra is just going to be an enormous blindingly bright... | [
"Related to this, the apparent colour of a black body is described by something called the Planckian locus. It turns out that as the temperature tends to infinity the percieved colour tends towards a blueish white, rather than \"running away\" to the shortest-wavelength violet you can see.",
"https://en.wikipedia... | [
"Wow that is fucking fascinating. Thanks. "
] |
[
"Do bones without growth plates grow later in life?"
] | [
false
] | They say growing ends because growth plates (epiphyseal plates) close. What about the bones (small bones, facial bones) that don't have them? Do they grow forever? Is that what's happening in acromegaly? -- "Our Face Bones Change Shape as We Age" | [
"Great response here. A big part of changing height throughout a single day is the periodic compression and decompression of intervertebral discs and other softer tissue. Acromegaly is generally due to the pituitary gland producing an excess of growth hormone long after puberty should have ended. Lack of nutrition... | [
"The article you posted has little to do with bone growth, and more to do with everyday stress on the human body. As we age, our bones resist gravity and the compression pressure exerted upon it throughout our everyday lives due to atmospheric pressures, walking, jumping etc. We are taller in the morning (slightly)... | [
"So there's different categorization of growth disorders!",
"I'm going to go off of memory so correct me if I get anything wrong here. ",
"Uncontrolled growth like you see in acromegaly is due to an excess production of Growth Hormone (GH). You also have excess GH produced in Gigantism. The difference between t... |
[
"Do people really wake up just before their alarm goes off, or do they just think they do?"
] | [
false
] | I was doing some reading on sleep and I came across an They basically measure people's brainwaves with an eeg as they try to sleep, and then wake them with a noise, and ask them to report whether they were asleep at the moment they heard the noise. People often report that they were awake, when the EEG shows they were ... | [
"Caveat: I only read the abstract, will take time to read the entire article later on. ",
"People are notoriously poor at subjective discrimination of sleep onset, sleep quality, and wakefulness, and it's been shown in study after study after study. I think the current research in question shows that a persons'... | [
"I regularly wake up, and look at my clock and it says 6:09, the alarm goes off at 6:10"
] | [
"Haha, I had so many patients ask me about that app when it came out that I finally broke down and got it and tried it for a week. For personal reasons I gave up on it pretty quick (I found it to be somewhat annoying to place the phone in the recommended spot each night). ",
"As for the science behind it, the b... |
[
"Why is it that a silver atom is stable with 60 neutrons, and 62 neutrons, but not 61?"
] | [
false
] | null | [
"I feel like a question like this comes up every so often. Here is the reasoning. Silver has 47 protons. That is an odd amount. For both protons and neutrons, there is a pairing term. Basically, if you have two protons or two neutrons they can occupy the same shell as long as they have different spins. So the... | [
"Indeed, nuclei with an even number of protons and/or neutrons are more stable. See ",
"this picture",
", which shows energies and possible beta transitions along an isobaric chain (series of nuclei with same mass number A=N+Z). If you want to have a panoramic look at what happens in the silver region, see ",
... | [
"Also worthy of note: the isobar chains for even-A (n+z=a) partially explains beta decay (beta+, beta-, and double beta decay) by means of relative stability of neighboring nuclei/explains why some nuclei can undergo two or more forms of beta decay."
] |
[
"\"....in humans with ADHD, amphetamines appear to improve brain development and nerve growth.\" Does that mean drugs like Adderall could have permanently beneficial effects even after usage has stopped?"
] | [
false
] | I apologize that all I have is this . Also, this question covers a few different topics that have flairs, so if there's a better one for this question, just let me know and I'll change it. I was doing my daily "Learn About Stuff" session and came across this line in the , which I thought was really interesting because ... | [
"This seems to be the implication of studies that show functional/anatomical improvements in treated ADHD patients. One problem is that the results are confounded by the fact aging itself seems to result in these same type of improvements, although you should be able to control for this. It is also unclear if the c... | [
"Thanks for the good response!",
"One problem is that the results are confounded by the fact aging itself seems to result in these same type of improvements, although you should be able to control for this. ",
"Could you clarify that \"this\" means neuron, dopaminergic or otherwise, growth? Or just synapse form... | [
"No prob!",
"By \"this\" I just meant that you can control for the impact of aging by comparing untreated and treated individuals over time. Alternatively as long as you are looking at a given age group and comparing treated to untreated you would probably be okay. You could run into trouble though if your treate... |
[
"If an object rapidly accelerated away from you and reached Mach 1 would you still hear the sonic boom?"
] | [
false
] | sorry if worded poorly | [
"You will always hear the object (until it is too far away and local noises and dampening make it too quiet to hear) regardless if it is below or above the speed of sound. The sonic boom is simply the shockwave caused by a supersonic object. That shockwave won't pass over you if you are directly behind an object.... | [
"That shockwave won't pass over you if you are directly behind an object.",
"Could you expound on this? It seems to contradict another response I received.",
"Namely this:",
"I'd say it would be audible, as the boom propagates and expands in a roughly conical shape behind the generating object. ",
"Color me... | [
"For an object that doesn't hit supersonic speeds until it is already in front of you, the cone will probably be entirely in front of you. Hence, no boom."
] |
[
"How do animals know how to move in a pack, fly in a flock, swim in a school, etc?"
] | [
false
] | I've always wondered how birds and fish know to move together... | [
"This article",
" should answer your questions; the \"See also\" links are also good reads.",
"Basically each animal watches other animals around it and makes a decision based on what they do. So they work as a collective organism."
] | [
"Oh wow, this helped a lot. Thanks!!!"
] | [
"This paper",
" is also a favorite of mine. I particularly like:",
"Interestingly, besides the front–back distinction between leaders and followers, we also found evidence of a left–right effect. During homing, the more time a bird spent behind a particular partner, the more likely it was to be flying to that ... |
[
"What's happening during the \"walking ghost\" phase of acute radiation poisoning?"
] | [
false
] | I read that there's a latent period after acute radiation poisoning where there are no symptoms. Like, you take a huge dose of ionizing radiation, feel sick for an hour, and then go for days in seemingly good health, before you collapse and die. How does that happen? Why does your body suddenly break down after the "wa... | [
"Acute radiation poisoning is the result of damage to very specific cell populations in the body. Radiation is much more lethal in cells that are undergoing cellular division. As a result, the stem cell populations that produce blood cells and intestinal tissue are most sensitive.",
"In short, what happens is t... | [
"That is basically what is done, yes. You need to provide red blood cells and protect from infection (due to white blood cell loss) while either the bone marrow repairs or a bone marrow transplant is given.",
"Also note that acute radiation poisoning is an exceedingly rare event and so there isn't too much clini... | [
"Thanks for the response! One question, though: how possible would it be to continually give blood transfusions to a walking ghost, in order to replenish their blood? Or to give an emergency marrow transplant? Assuming the intestinal damage was a nonissue, of course."
] |
[
"Why does mixing paints give rise to a new coloured paint?"
] | [
false
] | [deleted] | [
"Light can be composed of multiple colors. Paint filters the colors that leave its surface.",
"Red paint filters blue and green light.",
"When you mix paints, the new color is the sum of the leftover colors.",
"That's why when you mix a bunch of different colored paint, you get black."
] | [
"\"cheap\" or \"defective\" isn't the right way to think about it, you should be suspicious that I'm somehow wrong.",
"That's a good question, the statement I said about paint filtering is correct but essentially incomplete. In that sense the mixing of all the paints is a really poor example (although a good star... | [
"\"cheap\" or \"defective\" isn't the right way to think about it, you should be suspicious that I'm somehow wrong.",
"That's a good question, the statement I said about paint filtering is correct but essentially incomplete. In that sense the mixing of all the paints is a really poor example (although a good star... |
[
"Physiologically how do cats purr?"
] | [
false
] | null | [
"The muscles of the \"voice box\" (larynx) rapidly expand and contract, opening and closing the glottis (the opening of the throat connected to the vocal cords, which allows for control of vocalizations)",
"There may be a specific region of the brain called a neural oscillator that controls purring (probably amon... | [
"From what I understand, cats do not control the ability to purr, and it's more a central nervous response. When they breathe in, air vibrates over the laryngeal muscles - though the real reason they do this is still debated. ",
"You might enjoy the following library of congress site on more info ",
"why and ho... | [
"On a similar note, I’ve always wondered how much of their tail movement is involuntary. Is this known? I sometimes feel that they almost don’t even know it’s theirs."
] |
[
"In Asimov’s “The Gods Themselves”, he says that people born and raised on the moon would look younger, longer. The claim is that wrinkles and typical aging signs are caused mostly by gravity. How accurate is this?"
] | [
false
] | null | [
"The moon doesn’t have any protective atmosphere or magnetic field to block radiation either, I’m sure you would find skin cancer to be ",
" of a problem. Not to mention astronauts lose muscle mass and bone density in low-g environments. "
] | [
"The moon doesn’t have any protective atmosphere or magnetic field to block radiation either, I’m sure you would find skin cancer to be ",
" of a problem. Not to mention astronauts lose muscle mass and bone density in low-g environments. "
] | [
"Well, it's a good thing Asimov was better at science-fiction than he was at physiology.",
"There are two things that cause wrinkles: breakdown of collagen/decrease of collagen within the tissue and redistribution of fat. ",
"So lets talk about the first one: Collagen. Collagen is a protein present in basic... |
[
"How do deodorant stains on shirts form?"
] | [
false
] | null | [
"Idk if askscience is the place for this but I figure you guys would know..."
] | [
"I think a major component is aluminum oxide from hydrolysis of the aluminum chlorohydrate that is the common antiperspirant in deodorants. That should be removable in strong acids or bases, but the fabric of the shirt is probably even more susceptible to those."
] | [
"Discovery Health",
" has a good writeup on this. Essentially, it has to do with the chemical interaction of the materials in the antiperspirant/deodorant and sweat. Some possible solutions to remove the stains are listed.",
"I personally pick up a six pack of Hanes cotton shirts every six months to a year an... |
[
"Is there any legitimate evidence against the theory of evolution?"
] | [
false
] | null | [
"The theory of evolution by natural selection is a scientific theory, so by definition, ",
".",
"Scientific theories are evidence-based. This means that when new evidence is collected which does not fit or opposes the existing model, that model must necessarily be changed in order to fit all evidence. In fact... | [
"A related thought: it is foolhardy to assume that we know anything with 100% certainty. However, I do think that if \"the theory of evolution\" is ever to be proven wrong it would be analogous to how we consider Newtonian physics to be wrong today. That is, some unforeseeable details would have to arise that could... | [
"they would change their theory to match the evidence.",
"I feel like it's worth mentioning/emphasizing that this process of revision is a ",
" thing, and a normal part of science.",
"I've witnessed people pointing to statements like this and twisting them around to use them as anti-science ammunition along t... |
[
"Chance calculation, what are the odds of this?"
] | [
false
] | In Belgium we have something similar to the Social Security Number. It's an 11 digit number, the last two being a check digit. Example: 72020290081 If you want to calculate if the number is valid, you take the first 9 digits and calculate the modulo 97. Example 720202900 % 97 = 16 You then subtract that number from 97,... | [
"1 in 100.\nThe first 9 digits do not really matter at all, you don't even have to care about what the check sum actually is, just that it is two digits long.",
"The last two digits of your 11 digit number are also chosen at random.\nSo your question becomes. \"When i choose a number from 0-99, what is the chance... | [
"Sounds to me like our SSN's are easily guessed :p",
"The check digits aren't designed to prevent guessing (they do a terrible job at that), they're designed to prevent (or rather help detect) transcription errors."
] | [
"Fellow Belgian here!",
"It's quite simpel, the first 9 numbers determine what the last 2 numbers should be. At first you'd think that you'd guess these last two number would be 1 in 97. ",
"However you have to multiply this with the chance that you pick a valid number, so between zero and 96. So this is 97 i... |
[
"Are there examples of large molecules that make crystalline solids?"
] | [
false
] | I am not too knowledgeable about crystals or crystalline solids or solids. I will try to ask my question in as plain English as possible, and use the jargon only when necessary. I define crystalline solids as having a unit cell which repeats. The order of lowest energy for the molecules of a crystalline solid is the pa... | [
"Is there a clearer definition of a crystal?",
"The definition you have is actually quite good. Basically, a crystal is a solid with long range order. This means that you can infer the position of any atom in a crystal if you know the position of any other one. Therefore the crystal structure can be represented b... | [
"To date, the largest structure ever determined was that of adenovirus. The viral particle is 150 megadaltons and contains roughly 1 million amino acids. It took researchers 10 years of hard work to produce the structure. You can read about it in Science:\nCrystal structure of human adenovirus at 3.5 A resolution. ... | [
"Of course! Polymer chemistry can be a bit strange and is still an active area of research, but almost every piece of plastic that you use is essentially a large crystal of polymer chains. Although most are not 100% crystal due to ideal properties for end use applications, there certainly are examples of very large... |
[
"As the human body goes from being an infant to an adult, are there any organs or body parts that become smaller instead of larger?"
] | [
false
] | null | [
"There is at least one example i can think of off of the top of my head. \nThe thymus gland is very active in young children, and becomes far less so as we near adulthood. As far as the gland itself actually shrinking, i dont think it does, but The active cells which carry out glandular functions are replaced by ad... | [
"To add onto this, there are also the Foramen Ovale and the fontanelles. Not exactly organs, but mabye still interesting.\nThe Foramen is an opening between the Atria in the heart, allowing blood to bypass the lungs in an unborn child, and closes after childbirth The fontanelles are spaces between the bones that ma... | [
"Growth plates start shrinking after the first growth spurt, and then seal off after the teenage growth spurt.",
"I suppose ovary egg numbers decrease after birth (after menarche, really). But idk if the actual size of the organ is affected by puberty/early aging.",
"Not absolute size, but percentage of bone ma... |
[
"When we view pictures of supernovas, nebulae, quasars and suchlike, are they always more colour enhanced than the actual structures or are there some that would be just like that if seen close up?"
] | [
false
] | null | [
"When you take a picture with a camera, for each pixel you will have a red, green, and blue sensor, which when combined, allows you to capture colour images.",
"With the highly sensitive CCD sensors in telescopes, there is only one sensor for each pixel. To create colour images, separate images are taken with col... | [
"The Orion Nebula is pretty typical in color intensity, in fact it's pretty bright for a nebula. You wouldn't be able to see the bright colors we see in photographs with the human eye in other nebulas either."
] | [
"Nebulas have a very low surface brightness, and our eyes aren't very sensitive to color in dim light. A nebula from close up would look similar to what it looks like through the eyepiece of a telescope. Mostly gray, but with some subtle color.",
"For example, this is what the ",
"Orion Nebula",
" looks like ... |
[
"Is most of the energy you get through eating another organism that previously living organism's ATP? / How do you get 'nutrients' from your food? Where do they go? What do they do?"
] | [
false
] | I'm looking for a fairly molecular level view. Are there some keywords I can google? Thanks for any all answers :) | [
"No, you do not get the energy from eating other organisms' ATP. I would like to first clear a common misconception on ATP. ATP is a mediator for ",
"cellular energy transfer and they function primarily within cells; they do not get transferred between cells and certainly do not get transported around the body as... | [
"If you want a fairly molecular level view, I'd pick up a biochem text book and look at the section on metabolism. It'll likely start with glycolysis, the TCA cycle, and oxidative phosphorylation. Then it would go on to the pathways for carbohydrate, fatty acid, and amino acid (broken down protein) metabolism.",
... | [
"No, we actually store very little ATP (relatively speaking), and it's similar for the things we eat. In general, what we eat provides us with energy in the form of lipids (fats), carbohydrates (sugars) and amino acids (protein). These are all metabolized differently to provide energy, depending on the organ and th... |
[
"Is it possible for a spacecraft to enter an atmosphere 'slowly'? What forces would need to be at play to avoid violent atmospheric entry?"
] | [
false
] | This started as an 'ask sci-fi' question in my head when I saw a picture of a Star Destroyer within a planet's atmosphere, but got me wondering if, realistically, it would be possible for a craft to make a 'smooth' entry. Given a theoretical craft, could one use enough thrust against the planet's gravity to enter witho... | [
"Yes, it's technically possible, but it's ludicrously difficult. It's not as simple as overcoming gravity with thrust. ",
"When you're in low earth orbit, you're not stationary above the surface, you're moving at something like 8 kilometres per second (26 times the speed of sound), so if you want to avoid dramati... | [
"Interesting! Thanks."
] | [
"Werner Von Braun speculated in a book he wrote in the 1950s about what kind of rig it would take to parachute from orbit. When space travel becomes common and cheap I expect some of the extreme sports people will do it. Basically, you'd need some kind of enourmous wing area that can be decreased as the atmosphere... |
[
"Are all gas planets destined to become rocky planets at some point?"
] | [
false
] | I'm curious if ALL gaseous planets will (or are surmised to) eventually sort themselves into rocky planets. I Googled "was earth once a gas planet" and found and , but neither answers my question about ALL gas planets. Can Jupiter and Saturn look forward to a more "solid" future in several million (billion?) years? Al... | [
"Honestly, I would take the results of those articles with a grain of salt. \nThat paper has not yet been cited even once, and from my understanding most planet formation specialists do not take that paper very seriously. The details of planet formation are not very well understood; the only model that mathematical... | [
"The main thing to understand here is that there is really not that much rocky material in Jupiter at all.",
"Although you are obviously correct over all, that statement is somewhat debatable. While Jupiter couldn't \"become\" a rocky planet (short of it's gasses being stripped away somehow), it does appear to ha... | [
"Given that gas giants have been found around other stars in sungrazing orbits with very short orbital periods less than ",
", I think it's safe to say that gas giants can tolerate very close proximity to stars--much closer than Jupiter will ever come even to a red-giant sun. "
] |
[
"Is it possible to spin an accelerating spaceship to negate some of the effects the acceleration will have on humans inside?"
] | [
false
] | Say you wanted to travel at the speed of light but didn't feel like spending 50 years accelerating to it. You would need to endure pretty serious forces to accelerate faster which humans will probably not survive. Is it possible to spin the spaceship to counteract some of the acceleration forces? | [
"No, because of the way the vectors add. Have some ",
"high quality MS paint illustration.",
"The centripetal force (red) is at a right angle to the axis of rotation(1). If you spin along the acceleration axis, then the resultant vector (purple) is going to be larger than the force of acceleration(green) (2). "... | [
"Well, I don't beleive so, and I may be misunderstanding the question. However, here is my reasoning.",
"Lets say you are accelerating in the forward direction.",
"Is your axis of rotation parallel to the forward motion? In that case, you are squishing people to the outward shell of the spacecraft, as well as b... | [
"I think your best bet to reduce the stress would be to use something like ",
"liquid breathing",
".",
"Spinning won't work; if anything it'll make things worse."
] |
[
"So can I implement a random number in a quantum computer?"
] | [
false
] | If I had a quantum computer, could I write a program that takes in qubits set to |1> and outputs |0>+|1> then measures it to make a random number generator? Has anyone actually done this in reality to generate random numbers? | [
"You don't need a quantum computer, just a source of quantum noise.",
"http://www.technologyreview.com/blog/arxiv/25355/",
"Using a quantum computer to do this would be a bit like building a supercomputer and using it as a desk."
] | [
"You can buy a quantum random number generator for around 1100 eu ",
"here",
". ID Quantique was started by scientists at U of Geneva who did some of the first experiments on quantum 'teleportation'. Their device apparently uses a single photon at 45 deg. polarization fired at a polarizing beam splitter which g... | [
"Due to the ",
"Purcell effect",
", you should be able to change the probability by simply holding a metal plate near the device. Nothing is random."
] |
[
"Do I have an accurate understanding of how relativistic light-speed works?"
] | [
false
] | I've been racking my brain, trying to understand relativistic light-speed, and I think I had an 'A-ha!' moment in the shower . . Tell me if this is accurate: Our combined speed must ALWAYS equal light-speed. If we are standing perfectly still, all of our speed is moving through the time dimension - thus, we will observ... | [
"Our combined speed must ALWAYS equal light-speed.",
"While that's one way to make the statement, it's important that \"combined speed\" here does ",
" mean \"add up your speed through space and 'speed through time'\". The actual relationship is",
"v",
" + s",
" c",
" = c",
"where v is speed through s... | [
"You've more or less thought up one popular way of explaining things. The idea of having a single constant 'spacetime velocity' such that the time component is reduced by spatial components is a somewhat valid way to describe things.",
"I'm not sure you have the details quite right, though, although perhaps there... | [
"Likewise, to you on the spaceship it Earth is now moving really really fast and their time has slowed down.",
"Be careful here. If the ship is accelerating then it's possible for the person on the ship to see time on Earth moving ",
" than their own. This is how the twin paradox is ultimately resolved."
] |
[
"How long could ISS survive without resupply?"
] | [
false
] | Lets say some horrible diease wipes out most of humanity on Earth, and the ISS is left alone with no new supplies being brought by rockets. How long could the people on the ISS survive? What if there was only one person on the ISS? How long could he/she survive? Also, would they be able to go back to Earth without any ... | [
"Good timing of this question with the other thread about ISS life support. Again, I am an ISS flight controller in guidance and navigation (I have a limited understanding of the life support systems). Here is my take on this question.",
"When flying a spacecraft like the Space Shuttle or ISS the ground controlle... | [
"There are oxygen candles, which when lit, generate oxygen.",
"Wikipedia Link"
] | [
"ISS would need to be much higher for NO reboosts. Any reduction in needed reboosts comes with a higher altitude requirement since we are dropping due to atmospheric drag. Higher means less air.",
"If ISS were much higher, it could not be ISS, since the components are large and were launched on the space shuttle.... |
[
"How much gravity would be required for a light beam shown tangentially on a spherical surface to completely circle around the sphere and end up at the starting point instead of flying outwards?"
] | [
false
] | null | [
"This is only possible in the ",
"photon sphere",
" of a black hole. For a non-rotating black hole, there's a region from the event horizon to 1.5 times the event horizon radius, where light must orbit the black hole. You can escape this region by accelerating, but anything moving at a constant speed (like ligh... | [
"Needs to be circular. And it's an unstable orbit, so in practice light will either fall in or escape very quickly."
] | [
"We don't know the mass/radius relation for neutron stars that well, but they are unlikely to work. ",
"Causality requires r>1.41 r_s",
", and most models see them at larger than 1.5 r_s even close to their maximal mass."
] |
[
"What part of the electromagnetic spectrum would visible light be in if we didn't define it as colours that we can see?"
] | [
false
] | null | [
"What kind of answer are you looking for?"
] | [
"For example, if we saw colour only in the X-Ray part of the spectrum, how would we classify what we now consider visible light? Would it just be a cross between high energy infrared and low energy UV? Basically, other than the fact that we can see it, what makes visible light special?"
] | [
"Well you could describe it in terms of the wavelength, frequency, or energy of the light. Or you could describe it in terms of the temperature of blackbodies that produce it, or the types of atomic or molecular transitions that create it."
] |
[
"How can scientists estimate the lifespan of the universe if gravity causes all planetary masses to experience time differently on a major scale?"
] | [
false
] | null | [
"It's not usually a big effect. To get something like the gravitational time dilation they showed in Interstellar you need to be sitting pretty much right on top of a black hole. At the speeds and gravitational fields we typically deal with in astrophysics, time dilation really doesn't add up to much, except in a f... | [
"No. For time dilation you need local mass concentrations, a uniform matter distribution doesn't lead to any unusual effects.",
"Time dilation for us relative to an observer far away from galaxies is a few parts in a million - compare this to our uncertainty on the age of the universe from other sources, which is... | [
"Thanks! That helps a lot. Couldn't the big bang, at the beginning of the universe, have caused a great deal of space-time curvature upon explosion... considering that it was a singularity of astronomical density? Would this have caused the estimated lifetime of the universe to render differently?"
] |
[
"Why do massages feel good?"
] | [
false
] | I understand a fair bit about the sensory relay of mechanosensors. However, what I can't wrap my head around is why squeezing muscles (especially when someone else does it) feels good. Furthermore, what's the evolutionary benefit of having this positively reinforced behavior? I realize not everyone enjoys massages, but... | [
"(1) Not everything is adaptive. There need not be an evolutionary benefit for enjoying a massage, just like there is probably no evolutionary benefit to a man enjoying being pegged with a large black dildo.",
"(2) Basically, muscles that are overstimulated often respond by losing tone (i.e., they are more resist... | [
"This may not be what you're looking for, but it's worth noting that getting a massage can/does result in a spike in the hormone oxytocin. Oxytocin plays a role in social behavior and could be responsible for some mood change following a massage.",
"Check out this TED talk on the subject: ",
"http://www.ted.com... | [
"I think that this is a deep question because the definition of \"good\" is so broad. Some may like massage because they are in pain and massage relieves pain. Thease are physiological, and others might be because of psychological reasons. \nOne of wich is touch deprivation.\n\"",
"http://www.uab.edu/Communicatio... |
[
"How can light be circularly polarized?"
] | [
false
] | I recently heard that modern 3D movie glasses take advantage of something called circularly polarized light. I can visualize how light can be linearly polarized (electromagnetic field just going back and forth) but how can it be circularly polarized? | [
"The textbook way is using a ",
"quarter waveplate",
". This is an anisotropic material where light moves faster along one direction in the material than the other. One then puts linearly polarized light through with its polarization at a 45 degree angle between the fast and slow directions. Then while it is in... | [
"If you are familiar with linear polarization you will remember that the x and y components of the electric field oscillate in phase with each other. ",
"Elliptically polarized light is simply the case where the electric field components oscillate out of phase with each other. This leads to the resultant electric... | [
"Riiiiight, so in the video is the x component the electric field and the y component the magnetic field(or vise versa)?"
] |
[
"Can Psilocybin (magic mushrooms) increase neural plasticity in the ederly?"
] | [
false
] | From what I understand, a person's ability to learn reduces as they age because their neural plasticity decreases. I'm guessing it's because the connections between neurons harden, making it difficult to make new connections. I recently read about research with the effects of Psilocybin on the brain, and how it tempor... | [
"Well, it's an interesting thought, but even if this ",
" a reasonable idea, we are significantly lacking in the background knowledge necessary to determine whether or not it would have a positive effect. Let me explain.",
"Your assumption that learning reduction is due to neural plasticity may or may not be a... | [
"the modification of the brain due to stimulus is directly correlated to the perceived vividness of any cognitive stimuli!",
"What? What is your operational definition of \"vividness\"? And no, I would not agree with that statement.",
"that the pathway being triggered here directly modulates the intensity of ... | [
"Sweet. Ok. Nowhere in the actual paper or in this NBC article does it say that neuronal connections are ever severed, or destroyed. I think what you meant to say was that certain brain regions are temporarily inhibited or suppressed in activity. ",
"I am very familiar with this paper, since it was pretty awesome... |
[
"How is actual sleep different from \"sleeping\" via anesthesia?"
] | [
false
] | null | [
"(cont)",
"The last big group of anaesthetic drugs are the gasses. The anaesthetic gasses probably work on receptors on the intramembrane-part of transmembrane molecules of ion channels in the neurons. This is also a widespread effect all over the brain, and in inhibits activity a lot less specifically than some ... | [
"(cont)",
"The last big group of anaesthetic drugs are the gasses. The anaesthetic gasses probably work on receptors on the intramembrane-part of transmembrane molecules of ion channels in the neurons. This is also a widespread effect all over the brain, and in inhibits activity a lot less specifically than some ... | [
"Given this, what would you think is the best option for sleep recovery... Say from not being able to sleep due to infants, jet lag, plain old overwork and deadlines etc. It seems these days it easier to find ways to stay awake and alert (caffeine, modfafinil etc) but not as many aids to actually recover on some of... |
[
"What would an inductor made of a perfect conductor like stanene be like?"
] | [
false
] | null | [
"Well we generally assume that inductors have zero resistance in simple calculations, so they'd be \"normal\" in that their behavior would adhere well to the way we treat them. ",
"If you have an inductor which is a poor conductor, you may notice that your real circuit doesn't adhere well to your mathematical tre... | [
"So an inductor that has no resistance will behave the same as a inductor with the resistance of steel? "
] | [
"No. And inductor with no resistance will behave more like an idealized homework problem than an inductor with resistance. Real inductors usually do have some resistance."
] |
[
"Is there a (theoretical) superconductor for heat instead of electricitiy?"
] | [
false
] | null | [
"No, there is not. Firstly, heat can be carried in many ways, through electron and phonons usually but also through more exotic things like magnons, spinons, etc. To have a \"heat superconductor\" all of those degrees of freedom would have to become superconductive simultaneously. Let's just look at phonons.",
... | [
"Superfluids have very high thermal conductivity, some references say \"infinite\", others give figures much higher than copper (it probably depends on temperature, just guessing though). The thermal conductivity is so high that they transmit heat in waves, known as \"second sound\". It doesn't occur by conductio... | [
"Linear momentum isn't, in general, quantized and I'm not sure one way or the other what the photoelectric effect has to say about that regardless. ",
"It has to do with the fact that acoustic phonons are gapless and for \"phonon superconduction\" to occur, they would have to acquire a gap. In electrons in metal... |
[
"Why is the speed of light relative to the energy of an object? Is there an intrinsic relationship between the speed of light and energy of an object beyond this equation? It seems like an arbitrary constant to me."
] | [
false
] | null | [
"Can you explain what you mean by \"the speed of light is relative to the energy of an object\"? Which equation are you referencing?"
] | [
"E=mc"
] | [
"Ah, interestingly, I just answered a different question which I think will answer yours as well. You can read it ",
"here",
"."
] |
[
"Would a large enough explosion disperse a tornado?"
] | [
false
] | [deleted] | [
"A large enough explosion would disperse the solar system etc. ",
"A proper question is how large of an explosion would you need. Somone that would be able to answer this is someone versed in fluid dynamics. A tornado is a heat transfer machine based on the differential of two temperatures. You may be able to ign... | [
"A large enough explosion would disperse the solar system etc.",
"Best answer in this forum, ever"
] | [
"I came here to say this. When you were a kid and smashed the whirling vortex of water in your bathtub as it drained it would stop then just reform again. "
] |
[
"Can we use evolution to inexpensively solve the problem of antibiotic-resistant bacteria?"
] | [
false
] | I will state the problem and pose a potential solution and I would like to know why the solution would/wouldn't work. Problem: Some (and increasingly more) bacteria are resistant to many antibiotics. The widespread use of antibiotics outside of medicine plays a significant role in this (so says Wikipedia). Individual ... | [
"Good job! You've discovered ",
"Antibiotic Rotation",
" on your own. ",
"It's an effective strategy for the exact reasons you stated. It's used in a much shorter time period than 10 years because exposing bacteria to the same drug for 10 years would lead to the opposite effect of what you would want. That... | [
"Medical student (almost doctor!) here.",
"\nGood thought process, you definitely have a good handle on evolution. If this policy were to be able to be enforced 100% worldwide for a significant period of time, it would ",
" work.",
"\nA couple of issues though:\n1) Good luck getting the small pharmacies in s... | [
"There's also an ethical question here... What happens when the banned antibiotic is the only one that will kill a life-threatening infection? Should we let that person die for the good of the population at large, or do we make exceptions for certain people or certain situations?"
] |
[
"Why do the toxins from Jellyfish, Scorpions, Manta Rays etc. always give a stinging feeling?"
] | [
false
] | null | [
"Jellyfish is because they are covered in hundreds of things called nematocystes which is like being stabbed by hundreds of tiny needles. This video shows it. \n",
"http://time.com/3136474/jellyfish-sting-slow-motion-microscope-video/",
"I'm not sure about the other two but for scorpions I imagine it depends on... | [
"Yep, as far as I know, stinging is really just a pure pain signal and there could be lots of reasons. Yep one reason is mechanical disruption (jelly nematocysts, insect stinger etc). I know a lot of insect pain comes from either strong acid or base, and that most reptile toxins are large proteins (often proteases ... | [
"To put it simply it's just to cause pain. Correct me if I'm wrong, but the neurotoxins in jellyfish, for example, cause more serious injuries. To use it's just painful stinging that varies from animal to animal. Like the Stonefish, which is deadly motherfucker you don't want to mess with. In conclusion, most of th... |
[
"I accidentally threw a non-rechargeable battery in a charger with some rechargeable batteries a day or so ago. I only noticed this morning. Did I narrowly avoid something catastrophic?"
] | [
false
] | From what I understand, brands of rechargeable battery and charger are interchangeable (seen on a Ray-o-Vac and Energizer websites, can't link now - my apologies), but the charger was Ray-o-Vac and the non-rechargeable battery was Energizer. Thanks in advance. | [
"You could have potentially caused the battery to overheat, rupture, and leak out some electrolyte. I've never seen or heard of a (non-lithium) battery explode unless fire was involved. Standard alkaline batteries use potassium hydroxide (common name caustic potash) as the electrolyte, which has similar health & ... | [
"It is ozone. The electrical sparks produced in a brush motor cause O2 molecules to split apart, which then collide with other O2 molecules, which then form O3 (ozone)."
] | [
"You not so narrowly avoided a mess that at worse would have ruined your charger and given you a small chemical burn. It is less dangerous than running your blender."
] |
[
"What prevents DNA deterioration in radiotrophic fungi?"
] | [
false
] | If these organisms get energy from gamma radiation why is their DNA not turned into "Swiss Cheess," for lack of a better word? | [
"It looks like they use melanin to absorb the radiation. If the radiation is absorbed by melanin, then there's none left to damage their DNA."
] | [
"I think you are overestimating the amount of DNA damage that radiation causes, and also overestimating the amount of radiation that we study radiotrophic fungi with.",
"Different organisms have different sensitivities to radiation. In general less complex organisms are less sensitive to DNA damage. Humans worry... | [
"Hey something I'm working on. The mechanism is unknown, but the energy of the gamma radiation is being reduced by the melanins to reach a level for photosynthesis. The chemical structure of melanin polymers may allow for the photons to transition into a lower energy state or the melanin may just be absorbing the e... |
[
"Why can I see my LED lightbulbs flicker when I see them in my periphery, but not directly?"
] | [
false
] | null | [
"The critical flicker frequency, as in what ",
" lower threshold frequency something must flicker for the eye to detect it, is not the same over the whole retina. The peripheral retina tends to be able to detect higher frequency flickering than the central parts of the retina because the outer parts of the retina... | [
"Evolutionarily, this makes sense too. If there is movement at the fringe of your visual field it could be a predator and you want to be alerted to it as fast as possible."
] | [
"Rods are also more light sensitive in general, so you have better peripheral vision in low-light situations than central vision."
] |
[
"What would happen if you opened a carbonated beverage in space?"
] | [
false
] | To be more specific, I mean actually in the vacuum of space, not inside the ISS. | [
"Assuming the can was at room temp and not frozen solid, the effect would be pretty much what you would imagine: a large relatively violent spray that would mostly (if not completely) empty the can. Due to the absence of pressure, the 'fizziness' or the carbon dioxide would be much greater than it is at sea level... | [
"And this is assuming the can is able to withstand the pressure(which should be at least higher than atmospheric pressure, but exactly how much higher i'm not sure) Other wise your can explodes as soon as you take it to vacuum."
] | [
"Nope. A soda can or bottle would be just fine in a vacuum."
] |
[
"Why does an RH+ mother's cells not attack their RH- baby?"
] | [
false
] | null | [
"Hi, Rh positive mothers will not have antibodies to the RH protein. If they produced antibodies, they would attack their own cells. \nThe issue with Rh occurs when Rh negative mothers produce antibodies against the Rh antigen in their baby’s blood. The Rh antigen in this case will be recognised as foreign by the R... | [
"Back in the day, yes, at least on second+ pregnancies (as it typically takes time for the antibodies to develop, usually the Rh- body can tolerate one pregnancy with an Rh+ fetus). Nowadays, a blood product called Rhogam is readily available in most industrialized countries, and pregnant Rh- people are given Rhoga... | [
"A nice, succinct explanation. Good on ya.",
"I think some of the confusion some experience with this subject is the difference in expression between Rh factor and A/B antigens. Like if you're A you have anti-B. But if you're Rh+ you don't make Rh- antibodies. It's either the presence or lack of the Rh and that d... |
[
"Do ants really only think in algorithms?"
] | [
false
] | [deleted] | [
"Firstly, 'thinking in algorithms' doesn't really mean anything specific. Thoughts ",
" algorithms in some sense, and everything probably thinks in algorithms.",
"The author says that this ant does not know why it is doing those action.",
"The author doesn't know what the ant knows. He's probably doing some a... | [
"Then evolution would be a slow form of ",
"."
] | [
"There was an interesting discussion of this on one of the NECSS podcasts of The Skeptic's Guide To The Universe. ",
"Researchers looking into",
" how ants can be such great architects found that their behavior is directed by following only three simple rules:",
"The ants picked up grains at a constant rate, ... |
[
"What will happen to hot objects in vacuum?"
] | [
false
] | null | [
"Hi Gryffin317 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 foll... | [
"'Physics'"
] | [
"Physics"
] |
[
"How is it possible that steel and concrete have the same thermal expansion rate?"
] | [
false
] | null | [
"Steel and concrete don't have exact coefficents of linear thermal expansion, but iron and concrete have similar coefficients. From ",
"this data page",
", concrete is 12E-6/C, while iron is 11.8E-6/C, which is why iron rebar is used with concrete. ",
"This is convenient coincidence, which causes any stresses... | [
"Upon further inspection, I think you're right. I believe the thermal compatibility of iron and concrete is just a coincidence, but just in case, I shot a message to my professor who has a doctorate in material science. Will return with results."
] | [
"Does this really answer the OP's question? While what you're saying is correct and well documented (thanks for that!), I think OP is more interested in what causes iron and concrete to have similar coefficients of thermal expansion. ",
"I don't know the answer, so if the mods delete this comment, I totally und... |
[
"How is thermal expansion (Or rather contraction) dealt with in space craft?"
] | [
false
] | Because it's pretty cold in space, so the metals would shrink. Landing pods and other space craft consist of metals so it seems like a big problem. I don't know if I should be asking here or in engineering. Thanks in advance. | [
"A 3mm gap in an air tight surface is a pretty big deal, as is a change in length for an optical system. The stresses that can build up from a CTE mismatch can be pretty significant. That number is for steel, most aerospace systems are aluminum based so double that CTE.",
"You are very much not aware of the preci... | [
"Thermal expansion is a bit of a problem on spacecraft. The term we use is actually \"thermal shock\" where a very cold component goes into sunlight (or the opposite). One way that this is dealt with is called MLI (multi-layer insulation). This is the gold covering that you see on the sides of spacecraft (",
"ref... | [
"There are two big things to worry about when it comes to thermal contraction. ",
"1) Temperature gradients: the same piece of material at two different temperatures will try to be at two different length scales, and there must be a stress to fit them together. ",
"2) Material mismatches: two different material... |
[
"If two points determine a line, two parallel or intersecting lines determine a plane, then does two parallel or intersecting planes determine 3d space?"
] | [
false
] | In 4d geometry. | [
"To add a tiny bit to this:"
] | [
"In general, in ",
" (",
"-dimensional vector space), a (",
"-1)-dimensional affine space is described by an equation of the form",
"a",
"x",
" + a",
"x",
" + ... + a",
"x",
" = C",
"where the a",
"'s are coefficients not all zero and ",
" is a constant. So to determine the coefficients un... | [
"how is that done?",
"You just did it. Your definition is entirely correct. It's impossible to visualize, of course, but that doesn't really matter when describing it mathematically."
] |
[
"How can these two observers moving relative to one another each see the other's clock as moving slower than theirs?"
] | [
false
] | gives the example of a spaceship moving relative to the ground which shoots down a light beam which touches the earth and bounces back up to the ship. In the ship's inertial reference frame, it takes less time for the light to travel that path because from that reference frame the path is just a straight line with heig... | [
"In the ground's reference frame the trip takes longer for the light because it is a V shape where the v has height h.",
"The answer to your question is that this is true for both observers. Imagine Sarah on the ground sets up a perfectly aligned mirror up in the sky. She shoots a laser as Adam flies by in his sp... | [
"The big issue is the definition of the \"trip.\" To the uninitiated, it would indeed seem that if the ship's clock is running more slowly for the duration of the trip, then both the man in the ship and the man on the ground would be able to agree that the ship's clock is running late when the light makes it back t... | [
"Imagine Sarah on the ground sets up a perfectly aligned mirror up in the sky. She shoots a laser as Adam flies by in his spaceship. She watches it go straight up and down, yet Adam watches it travel in a V.\nThe scene from the video is just the opposite, yet it applies equally to both participants if you think abo... |
[
"Are viruses abiotic (non-living) factors of an environment?"
] | [
false
] | This questioned happened upon me when I was in my biology class. I'm just wondering since viruses are technically not living, are they considered a biological factor when interacting with organisms? | [
"As a side point I'd like to point out that describing viruses as living or not depends on your definition of life. A day or two ago I searched through old ask science posts for \"virus alive\" and found a lot of interesting discussion. What it basically boils down to is that it is hard for everyone to agree on e... | [
"I think one could attempt to prove/disprove whether or not a virus is alive by defining a simpler term than \"life\" (e.g. a \"cell\"). According to the cell theory, all living organisms are composed of 1 or more cells. So really, as a plant cell is different than an animal cell, they're both considered cells. But... | [
"Viruses are definitely not cells. ",
"Also, your proposal merely shuffles around the responsibility for answering the question (rather than conventional criteria for life, you're delegating the question to cell theory). This isn't actually resolving the issue. If you're a guy who believes viruses should be co... |
[
"What is the difference between a voltage regulator and a transformer?"
] | [
false
] | null | [
"A transformer takes one voltage as input and outputs another voltage. The output voltage can be higher or lower than the input voltage. Keep in mind that if you transform to a higher voltage you're not just getting free energy, though, because energy is voltage x current x time. ",
"A voltage regulator makes sur... | [
"Thanks for the reply. Do variable voltage regulators exist? With like a dial to change the output voltage?"
] | [
"They certainly do."
] |
[
"What happens to dead neurons?"
] | [
false
] | Wouldn't dead brain tissue build up in our heads once our neurons die? | [
"Our body contains phagocytes, cells that break down dead cells, sometimes into reusable parts. They also play a role in keeping out diseases and foreign particles. The brain carries an array of macrophages that execute phagocyte behavior, and will get rid of the dead cells if need be.",
"Sources:",
"http://www... | [
"I'll also add a little twist: a very recent publication has discovered (at least in fruit flies) that parts of neurons are cleared by skin cells (epidermal) rather than hemocytes (macrophages). I imagine the same process could be happening in humans too. ",
"Here's the article for those interested: \n",
"http:... | [
"Thank you!"
] |
[
"In mediums other than a vacuum, different wavelengths of light travel at different speeds. Does this mean that a certain wavelength of light escapes the sun more often?"
] | [
false
] | This is in reference to the idea that photons bounce around in the sun's mantle for eons before they escape. Does faster speed increase the amount of collisions the photon goes through as well? Are photons of a certain wavelength more likely to exit because they have chances due to the greater number of collisions? | [
"Imagine a bunch of cars on a road. They all travel at the same speed, but all the red cars have a special lane to themselves.",
"The cars come to a tunnel. Inside the tunnel, red cars have to travel at half the usual speed, but the other cars can carry on as normal.",
"Once they get to the exit, the red cars c... | [
"This effect applies more for transparent or near-transparent material. Most of the Sun is pretty opaque, so it's not really best to think of it as the \"same\" photon bouncing around until it escapes. It's better to think of it as photons being absorbed and new photons being emitted. This is important, because the... | [
"To clarify, that is in reference with respect to the elastic scattering of photons by electrons, known as Thompson scattering. Scattering in general may be affected by the wavelength of the light/photon, but as in the case of the sun, this is the accurate representation because its core behaves like a dense plasma... |
[
"Given DNA samples from a parent and child, could you tell which sample belonged to which?"
] | [
false
] | [deleted] | [
"Yes, you could tell which sample was the child, and which was the parent.",
"While by simple rules of relatedness, both samples are 50% related to each other. However, it is the identity of the 50% that would reveal parent and child.",
"In basic terms: 50% of the child's genome can be found in the parent. Exac... | [
"Nearly all gamete chromosomes are the result of recombination (the sex chromosome inherited from the heterogametic sex is the one exception). The two samples will share 50% of their DNA, but in one sample that shared half will consist of one entire chromosome from each pair of chromosomes and in the other sample ... | [
"Nearly all gamete chromosomes are the result of recombination (the sex chromosome inherited from the heterogametic sex is the one exception). The two samples will share 50% of their DNA, but in one sample that shared half will consist of one entire chromosome from each pair of chromosomes and in the other sample ... |
[
"Can denatured alcohol be filtered for re-use as a solvent or is it impractical?"
] | [
false
] | I worked in a woodshop for a period of time and we used a lot of denatured alcohol. Mostly for cleaning paint brushes and the like. I was wondering if the used product could be filtered to be re-used or does the alcohol bond with the solute in a way that would prevent a simple filter from creating clean recycled denatu... | [
"It is perfectly possible to purify it, but depending on the level of purity you want it might be pretty hard maybe not even feasible as it could cost more to purify it than to simply make/buy more. ",
"The general rule of thumb in chemistry is that it is easy to put things together and it is hard to pull them ap... | [
"Distillation is usually more trouble than it's worth outside of a lab or controlled industrial setting. Without ample ventilation and attention, a still can easily turn into a bomb."
] | [
"If you were running a distillation setup as described here then anything lighter than the ethanol (methanol, acetone, etc) would come off first (your \"lights\"). Then your ethanol and water would distill, and after all the ethanol/water was gone you would distill the \"heavies\" such as pyridine and naphtha. If... |
[
"Do humans acclimatize to extreme climates over a period of time?"
] | [
false
] | [deleted] | [
"Section of 'humans' from Wikipedia article on acclimatization",
". Be sure you read the definition of acclimatization at the top as well.",
"So yes we do but it is poorly understood. The example you gave of \"feel cold/warm\" is a little different and could be more psychological than physiological. Like how... | [
"I agree there is a psychological aspect to our perception of the climate. On the other hand, and if I may be allowed to use anecdotal evidence here, I would consider being able to endure extreme weather without suffering physical symptoms to be a definite physiological effect of acclimatization. Somebody who is us... | [
"No it is a question with respect to your views so it should be fine. I'm not well versed enough to determine what is physiological and what is psychological. I agree though that I can \"handle\" the cold up in Canada better than a person of similar race to me who was raised in California. Whether it is me being... |
[
"What causes Heisenberg's Uncertainty Principle to be true?"
] | [
false
] | I've seen three explanations for the reason Heisenberg's Uncertainty Principle occurs. I'm not going to iterate them because I don't want to unduly influence responses, so I'll keep it simple: why is ΔxΔp ≥ h/4π ? Edit: why did I think momentum was rho? | [
"It's built into how quantum mechanics works. Observable quantities are Hermitian operators, and any two operators which don't commute don't share a basis of eigenstates. In other words, if you have a state where one of the two non-commuting observables is well-defined, the other necessarily isn't.",
"There's a "... | [
"As a very basic explanation: measuring a property of a particle forces it to take a single, definite value of that property (we call this being in an eigenstate of the operator that corresponds to that property). ",
"Many measurements have sets of possible results (i.e. eigenstates) that do not coincide. For exa... | [
"As always, ",
"u/RobusEtCeleritas",
" gives a technically detailed and correct answer.",
"However, for those who aren't well versed in the quantum mechanics formalism, I think the analogy from classical ",
"wave-packet",
" uncertainties goes a long way.",
"There is a fundamental trade off for classical... |
[
"How long does sleep, or lack thereof, affect you?"
] | [
false
] | as a sleep enthusiast, i'm curious about how long a good night's sleep, or rather the opposite, will affect your mood, energy, motivation, etc. more specifically (and this has always bothered me), has anyone heard that an individual feels the effects of the amount they sleep not the following day, but instead two days ... | [
"Fatal familial insomnia",
"Insomnia, hallucinations, complete inability to sleep, dementia, then ",
". Average 18 months from onset of symptoms to death.",
"Not a doctor, but this is something interesting to chew on. Basically, this disease is caused by a rare genetic defect (dominant inherited) that typical... | [
"Guidelines to answering...",
"Keep discussion on topic and focused on answering questions scientifically."
] | [
"Guidelines to answering...",
"Keep discussion on topic and focused on answering questions scientifically."
] |
[
"Is it possible for there to be endothermic fire?"
] | [
false
] | Can there be endothermic fire? Or is it such that rapid oxidation of materials (which my school chemistry claimed was what fire basically is) by nature only exothermic? | [
"If you want to first classify fire id start by defining it as a heat exchange involving a flame, then analyze the flame's nature as a plasma (ionized gas) and what you need to sustain a fire. With these constraints it's exclusively exothermic"
] | [
"Isopropyl alcohol has very ",
"\"cool\"",
" flames. You can still totally burn yourself with it. Under bright lighting, ",
"alcohol fires",
" can be sort of bad because you can barely see it so people don't immediately realize that they're on fire and should take steps to correct this.",
"The mechanisms ... | [
"I would more generally classify \"fire\" as combustion i.e. oxidation. In this case you can have endothermic oxidation reactions e.g. N2 + O2 to give NO.",
"Although I am just arguing semantics."
] |
[
"With the talk of a functional bionic eye, would hallucinogens impact the users perception just like a real eye?"
] | [
false
] | null | [
"Oh yes. The physical tools of perception (lens, retina etc) are merely the first step in the process. Perception is highly constructive- you create what you see based on utility and past learning. The idea of direct realism/direct perception is not well supported in the vision research world. The way that huma... | [
"I think there are some incorrect assumptions about how hallucinogens work behind this question. It's a little bit like asking \"would Photoshop still work on pictures taken with a fisheye lens?\"",
"Psychedelic drugs don't usually produce \"hallucinations\", as in, you're not going to see a thing or person that ... | [
"yes, as long as they have a functioning vision center."
] |
[
"If the moon was created from an impact with Earth, could there be “Earth rocks” deep within the Moon?"
] | [
false
] | Could we learn about early Earth geology with rocks we found on the Moon? | [
"Most likely yes. The materials that flew off the Moon and Earth are pretty much indistinguishable because both were liquid for so long. From my understanding the bulk of the moon is made of the lighter elements that were able to be lifted off and not fall back into the gravity well whereas what we would call Earth... | [
"This turned out to be a specious argument! My bad people! I'm off to go do some reading...",
"Have a look at ",
"/u/siliconlife",
" 's ",
"comment",
".",
"If you're really curious have a look at ",
"The Constitution and Structure of the Lunar Interior",
" (its intended audience is geologists/geophy... | [
"During the impact between the impactor \"Theia\" and the proto-earth, material from both objects were mixed together. Collision models suggest that the moon should be mostly material from the impactor, along with some material from the proto-earth. However, the impact had so much energy that it completely melted t... |
[
"Why does 3D animation often look so horrible, but only in hindsight?"
] | [
false
] | null | [
"Yes, it likely will continue for a while until such time as careful examination of a CG scene cannot reveal that it isn't real photography. Advances in technology have improved our standards and lowered our tolerance for suspension of disbelief.",
"Computer games are much more difficult because they must be gene... | [
"A lot of it is hindsight, yes -- when something is better than anything we've seen before, we consider it to look good, and when something is worse than what we're used to seeing, we consider it to look bad.",
"But it's an aesthetic question, really. It's a little more complicated than your description implies, ... | [
"Also, why doesn't the same effect happen with 2D animation/games?"
] |
[
"How did the cicada's mating cycle come to be 17 years long? Wouldn't a cycle of only a few years be necessary to avoid lining up with predatory mating cycles?"
] | [
false
] | null | [
"It's very beneficial to take a prime number as the length of your mating cycle. If you'd take 4 years for example, any predator that has a cycle of 1, 2 or 4 would eat a large part of the population. If you take a prime number like 7, then predators with a cycle of 2, 3, 4, 5, 6 will all miss you. ",
"The bigger... | [
"Whilst this answer is right in terms of predator avoidance timelines I feel the wording is a little off. I'm sure MinecraftChrizz didn't mean it in this fashion but I want to clarify the language. ",
"Cicadas didn't choose a prime number life cycle. In reality, at one stage there were cicadas with varying or dif... | [
"Originally, there were likely X, Y and Z variants. Selection pressures favored X and/or worked against Y and Z. Y and Z either converged into X, evolved into something completely different or went extinct. X was able to breed, and therefore genes passed on. Population becomes mostly/entirely X.",
"This can be ap... |
[
"Are marine apex predators (sharks, dolphins, etc.) affected by all the mercury they intake?"
] | [
false
] | We've all heard about how dangerous it is to eat the meat of large fish due to the mercury they accumulate from the smaller fish they eat because we would get mercury poisoning if we ate too much. But I can't seem to find anything about the effects on the fish themselves--do apex predators in the ocean experience some ... | [
"Yes, apex predators likely experience mild mercury poisoning. It is doubly bad for us because we like to eat the apex predators (tuna, swordfish, shark)",
"Edit: ",
"http://en.wikipedia.org/wiki/Mercury_in_fish",
"\n",
"http://www.chem.unep.ch/mercury/report/Chapter5.htm"
] | [
"Source?"
] | [
"Yes, fish do experience the negative effects of heavy metal bioconcentration---deformities and physiological disadvantages\n",
"http://rd.springer.com/article/10.1007%2Fs00244-012-9816-x",
"On the note of health effects on humans, even avoiding the fattier (and of ten more tasty) cuts of certain fish can help ... |
[
"How do new cases of cholera arise, when there is no transmission from infected subject?"
] | [
false
] | null | [
"There is a reservoir in nature somewhere. Likely the intestines of animals.",
"The contaminated feces of these infected animals (or people) finds its way to a water supply, or other form of fecal-oral transmission, and new cases arise ",
"Viruses tend to be species -specific. Bacteria, like ",
" are not."
... | [
"Probably a breakdown in sanitation (handling of wastes) and water quality/availability.",
"Sewer workers flee war zone. Sewage treatment plants overflow. Raw sewage enters water table or water supply contaminating it.",
"Someone, or some animal with cholera takes a dump, its bacteria finds its way into a wat... | [
"Probably a breakdown in sanitation (handling of wastes) and water quality/availability.",
"Sewer workers flee war zone. Sewage treatment plants overflow. Raw sewage enters water table or water supply contaminating it.",
"Someone, or some animal with cholera takes a dump, its bacteria finds its way into a wat... |
[
"What happens to the atoms that comprise humans, when humans die?"
] | [
false
] | null | [
"A fairly basic explanation is that the molecules that make you up will be broken down or dispersed as your body decays (assuming you are buried or cremated and not mummified or died in a environment that is not decomposition friendly). They will be consumed by other lifeforms and be returned into the cycle of life... | [
"the same way that you grow from eating food, parts of your food are broken down and used to expand growth in your body. Calcium being used to build and maintain bones is the best example I can think of - but for anything more in-depth you would need to ask a biologist as this is getting beyond my confident knowled... | [
"How is it that the atoms will be components in other beings? "
] |
[
"Could we put a probe in orbit or onto Asteroid 2014 UR116 or any asteroid for that matter as it passes Earth?"
] | [
false
] | IF we have enough time that is, meaning if we knew its trajectory far enough in advance to prep a probe/lander for intecept? | [
"That's what was done with Rosetta and 67P. You still have to match orbits with the comet or asteroid you're going after, though, and sometimes that might mean it's easier to hook up with an asteroid that's farther away if the orbital constraints are more favorable that way, like if you're going to need gravity ass... | [
"Short answer is yes, it wouldn't be very different from a probe going to a comet or other minor solar system bodies.",
"But I'd like to clarify that ",
" means nothing. It doesn't make things any easier than a deep space object. In space we normally don't care about distance",
" , what we care about is how m... | [
"There's no reason why not. An approach similar to Rosetta/Philae would likely be met with similar success—or better, now that we can use lessons learned from that mission. As with Philae, the escape velocity off of the target would be so small that you'd need some way to stick to the surface, like the upward-fac... |
[
"What are some of the bleeding edge technology and science mankind is working on now and how would those affect our future?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"If you disagree with this decision, please send a ",
"message to the moderators."
] | [
"I don't disagree. But can you tell me where can i post this question. I'm new to this website."
] | [
"I am not sure, maybe ",
"/r/askreddit",
" or ",
"/r/AskScienceDiscussion",
" ?"
] |
[
"If multiplication is repeated addition, then what repeated operation is addition?"
] | [
false
] | null | [
"I've never answered an AskScience question before, so I hope this response is up to standard. I'll give it a shot!",
"In mathematics, there are statements called axioms which are elemental statements that are assumed to be true. Theorems are then proven to be true by combining these axioms in a meaningful (log... | [
"So basically it is iterated counting? :)"
] | [
"Yes. The reason that Porygon_is_innocent used the words \"iterated application of the successor function\" is that when you get into even more abstract mathematics, the successor function can be something other than counting. ",
"I don't have a great example for you though, perhaps someone more knowledgable tha... |
[
"Glycogen stored in the liver lasts for 12-14 hours, how much in weight is this glycogen?"
] | [
false
] | So I'm a undergrad majoring in biology, and while taking my Macro-molecules and Metabolism class my professor remarks that glycogen stored in the liver can last for 12-14 hours, to which I asked how much glycogen is that? He didn't have an answer, so I'm asking it here. | [
"Typically about 100 grams. This can also last to fuel the body for up to 22 hours before the body switches to breaking down protein and fat for energy. Muscles store about 400 grams of glycogen, but those bastards are selfish and since they lack the enzyme glucose-6-phosphatase, they cannot convert G6P to glucose ... | [
"I just finished a metabolism class as well. So if muscles lack the enzyme to remove the phosphate group they must use it at the site of breakdown. Would this imply that they would use their glycogen before the liver would be releasing most of its store? Would blood sugar levels not drop significantly until this... | [
"Hard to get an exact weight because one glycogen molecule is a glucose polymer with 'n' subunits. It's going to change molecular weight depending on if the cell is in a high energy or low energy state. Enzymes can cleave off/add on glucose molecules to glycogen. "
] |
[
"Are adinkras related to amplituhedrons? Can this relationship be described in a non-technical way?"
] | [
false
] | The , I am referring to are the ones developed by Gates and his colleagues to model equations underlying fundamental particles and forces. It would seem to me the two should be related, if not isomorphic. | [
"This seems like more physics than math to me. I can't find a precise mathematical definition of an amplituhedron anywhere. The closest I get is \"It generalizes the idea of a Grassmannian\". Can you link to the mathematical definition of amplituhedron that you're trying to work with?"
] | [
"No they are not.",
"What is your level of understanding of these topics ? Do you know group theory ? Quantum mechanics ? These are VERY technical topics, not only in the sense that they are complicated, but also in the sense that they are calculational tools. ",
"In non-technical terms:",
"Adinkras are a way... | [
"Thank you for taking the time to respond. That is a very useful explanation. It reaffirms what I thought, but also explains where I am confused.",
"These are naive questions based on intuitive understandings of generic descriptions devoid of math. Sort of like asking about cars without any understanding of w... |
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