title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Has the moon changed since the time of Galileo?"
] | [
false
] | [deleted] | [
"It has moved about ",
"14.15 meters farther away",
" on average. I'm not aware of any physical differences we could notice from Earth. It's still tidally locked so we always see the same side.",
"The 3.8cm is from ",
"http://curious.astro.cornell.edu/question.php?number=124"
] | [
"What desimusxvii said. The moon does get hit periodically by meteorites and we do have ",
"footage of the flashes",
". Plus of course we (humans) have left a lot of junk there. Overall though 'Almost completely unchanged' would be a better way of saying it."
] | [
"Definitely a lot of junk. What's cool is that the ",
"Lunar Laser Ranging Experiment",
" is still detectable from Earth."
] |
[
"Hey scientists, the colder it gets, the better my cellphone reception gets. Why?"
] | [
false
] | I live in the sticks, so cell reception can be pretty frustrating sometimes, but the last couple days I've actually had one bar of 4G, where usually I get two or three bars of 3G coverage. Is this a thing? | [
"Radio frequency (RF) energy is absorbed by, among other things, water. There is typically more water in the air when the air is warmer. Cold air cannot support as much atmospheric moisture so there is less absorption, and therefore more energy is able to make it from your transmitter to the cell site receiver.",
... | [
"and snow/ice are much more transparent too."
] | [
"Yep. The same goes for when you are in a crowded room. Lots of big bags of salt water (people) to muck up reception. "
] |
[
"Would drinking through two straws move more volume of liquid than drinking through one?"
] | [
false
] | Hi there, I really hope this question gets answered and taken seriously because it has been bugging me for a couple of days. I had a discussion with a few friends about this and we could not settle on an answer. Basically, assuming that there is an equal amount of suction, would drinking through two (or more) straws ac... | [
"The tricky part of your question lays in this assumption : ",
"Without this assumption, the answer is easy, there is less pressure losses if you use 2 straws instead of one (The cross section is twice as big). ",
"As your assumption doesn't give a estimation of the pressure losses due to the gap. We cannot ans... | [
"I think it depends more on the diameter of the straw and the viscoscity of the liquid. small straws are limited by friction loss of the fluid more than they are by your suction power. Adding another small straw should double your flow rate even with a small loss in suction due to lip gaps. A large straw such as a ... | [
"Years ago I conducted empirical experiments using 1 vs 2 straws (always a fixed diameter) using liquids of a few different viscosities. I did a very poor job of documenting my results, but I can report that in all cases the fluid volume/time transferred was greater in the 2 straw case. "
] |
[
"What would happen to my body if I showered non stop for a year?"
] | [
false
] | Food and water would be brought to me and as for exercise, I would be able to do whatever you can do on about a square meter. | [
"aside from turgidity, you'd suffer from profound infection. "
] | [
"Citation 1",
"Citation 2",
"Citation 3",
"Citation 4",
"Related search on PubMed",
"Image of trench foot",
"Other example of persistant exposure to moisture",
". Albeit anecdotal, it gets the point across I believe."
] | [
"It doesn't take a biologist to answer such a question. While Slypsy is right, a pathogen needs to be present for infection. However, its hard to believe that within a year, after ones flesh falls off, one would be \"just fine\". I'm operating under the assumption that at least the feet will be covered in water the... |
[
"What are the actual dangers of NOT turning off your cell phone before taking off in a plane?"
] | [
false
] | I have always wondered what might happen... | [
"Older models of planes used copper wire, not fiber optics or well insulated copper wires. ",
"Copper wires act like large antennas, and are subject to interference. Older electronics were more prone to emitting the types of electronic interference that ",
" mess with the long, uninsulated copper cables (thi... | [
"Also, when cell phones first came out, they were analog devices that put out far more power at the time. "
] | [
"Time for a kickstarter to fund that study. Pass a hat down the aisle of your next flight. \"Change for Letting me Keep Reading my Dam Kindle\""
] |
[
"How can gravity possibly be accounted for by quantum theory?"
] | [
false
] | If what we perceive as gravity is a 3d representation of a 4d distortion of spacetime and not a force between two particles, then what is quantum theory looking for? Is it trying to explain the interaction between mass and spacetime? Is this what we're trying to represent with gravitons? | [
"What we don't know is how to solve for the curvature of a particle that doesn't have reasonably precise position and momentum (quantum particles). So far no approach we've thought of has really worked out right..."
] | [
"... then what is quantum theory looking for? ",
"A more accurate description for the high-energy, short-wavelength gravitational physics. Relativity falls short and does not have a terribly accurate description of, for example, the border of a black hole. Consequently it cannot naturally explain observed pheno... | [
"Not always. There was a recent article on ",
"r/Science",
" about how the moon affects experiments at the LHC, and how operators there have to fine-tune the proton beams to correct for the disrepancies.",
"The reason the SM does not speak about gravity is because the SM is made up of gauge field theories (s... |
[
"With current technology and unlimited budget, is draining the North sea and connecting Europe and England possible?"
] | [
false
] | Inspired by this thread here: | [
"Fill it with money."
] | [
"dammit, you broke science."
] | [
"Paper mache continent. What could go wrong?"
] |
[
"How are large natural magnets transported?"
] | [
false
] | What the methods used to transport large and powerful permanent magnets to where they're needed without having cyclists sticking to the side of the truck along the way?? So far the best answer I've found involved either using a lead lined box or thick plates to 'absorb' the magnetic field lines but then how do they rem... | [
"Magnetic field strength decreases rapidly with distance. You don't need lead or plates or anything like that, just put the magnet on a wood pallet to keep it from sticking to the truck bed. "
] | [
"This page",
" at KJ Magnetics gives the low-down on how they ship the big, dangerous magnets like ",
"this monster",
". Bottom line, they pack them with a lot of space and measure the field outside the box to make sure it meets regulations regarding external magnetic field strength.",
"Edit: ",
"or this ... | [
"By \"natural magnet\", I'm going to assume you actually mean permanent magnet. Actual natural magnets (lodestones) are extremely weak.",
"When transporting permanent magnets, you can either put enough packaging around the magnet to keep susceptible materials at a safe distance, or you can build a box around the ... |
[
"Are any two given temperatures guaranteed to have every temperature between them?"
] | [
false
] | For example: if my hotpocket is 600 degrees in the middle, and 2 degrees on the outside, am i guaranteed to find every temperature between 2 and 600 in the hotpocket? | [
"Good question. The temperature in the hot pocket as a function of coordinates and time will be a solution to ",
"the heat equation",
".",
"At steady state, this simply becomes the ",
"Laplace equation",
", which shows up in many places in physics.",
"Solutions to the Laplace equation are continuous fun... | [
"Temperature is not defined for each individual particle. Temperature in the context of the heat equation is a scalar field which varies as a function of coordinates and time."
] | [
"A single atom doesn't have a temperature."
] |
[
"When Pangea was the only one continent, were there big islands built by volcano like Hawaii around the world?"
] | [
false
] | null | [
"Yes, though the records of them are a bit more fragmentary than the large continental portions which made up the bulk of Pangea. In detail, there were both intra-oceanic island arcs formed above intra-oceanic subduction zones (e.g. modern day analogues would be things like Java and Sumatra on the extremely large e... | [
"Sure, the ones highlighted in the van der Meer reconstruction (with the references they cite) are the Kolyma–Omolon superterrane in NE Russia (e.g. ",
"Stone et al, 2003",
"), the Anadyr–Koryak terrane in Kamchatka (e.g. ",
"Filatova & Vishnevskaya, 1997",
"), the Oku-Niikappu terrane in Japan (e.g. ",
"... | [
"Can you give examples of where these accreted terranes exist today?"
] |
[
"Are ants or other small insects able to communicate threats and dangers to the rest of their colonies?"
] | [
false
] | For example, if I spray part of a trail of ants with ant killer, will the survivors somehow communicate the danger to other ants so more ants don't continue moving towards it? | [
"Yes and no. It depends on where the threat is. I know two different ant systems pretty well, and I'll use them as two slightly different examples. ",
"Fungus farming ants, specifically leaf cutting ants, have a number of protective measures in place. If you disrupt a trail that is going out or coming back fr... | [
"Ants do most of their chemical sensing with antennae. In general, chemical sensing works by having proteins on the cell membrane which match particular chemicals. Chemical hits them, they change configuration, often releasing a different chemical inside the cell, which triggers...well, whatever. I don't know if... | [
"It's not hugely complicated, but it gets the job done. I think most ants use on the order of a dozen separate chemicals. But I don't remember exactly."
] |
[
"I'm tone deaf and cannot recognize different notes or any aspects of music aside from melody and rhythm, are there identified distinctions between the brains of musically gifted people and people who are not?"
] | [
false
] | null | [
"Are you sure you’re tone deaf? Most people who say things like this are commenting on their quality of musical talent or lack thereof. Neuroscientist Oliver Sacks has written extensively about music and the brain. \nMusical concepts can usually be learned/taught."
] | [
"This doesn't answer your question at all, but Einstein's brain had a distinct omega shape in his right hemisphere that has been attributed as a characteristic of his proficiency at playing the violin. \nThough, the brain isn't born this way - meaning the signature omega shape of violinist's brains develops with ti... | [
"If you play 2 different keys on a piano, do you hear a difference?"
] |
[
"Are humans the only species with beauty perception of faces?"
] | [
false
] | Are there other animals that are atracted by simetric (?) faces? (pardon my english, not a native speaker) | [
"Humans have to rely on the face more than other species for sexual selection as a product of evolution and culture. I.E. we are social and get cues from the face and we wear clothes that conceal our body. It is likely that we are the most extreme version. "
] | [
"Symmetric features typically indicate good genes. Mainly genes for proper growth during pregnancy, as it is when a fetus develops that most features develop and when most genes are expressed. It's important in realize that beauty is not a universal thing. We perceive beauty and are attracted to beautiful people be... | [
"I'm not sure about other animals, but in humans, faces are primarily encoded in a part of the brain called the ",
"Fusiform Face Area (FFA)",
". Googling it might lead to more info."
] |
[
"How does solid salt melt solid ice if no solution is made?"
] | [
false
] | [deleted] | [
"You must consider three equilibiria:",
"Ice == Water delta(G)_1",
"Ice + Salt == Salt(aq) delta(G)_2",
"Water + Salt == Salt (aq) delta(G)_3",
"We know that salt dissolves in water spontaneously, then delta(G)_3 is negative. Further, below 0C, we know ... | [
"It's the balance of all the factors in the reaction. There's also energy involved in breaking the hydrogen bonds in the water, and the ionic bonds in the salt, and the attraction of the ions to the water. In this case, though, most of those other factors are opposing the ice melting, and it's the increase in ent... | [
"It's the balance of all the factors in the reaction. There's also energy involved in breaking the hydrogen bonds in the water, and the ionic bonds in the salt, and the attraction of the ions to the water. In this case, though, most of those other factors are opposing the ice melting, and it's the increase in ent... |
[
"If pepsin and trypsin break down proteins into peptides why are people worried about Estrogen in foods?"
] | [
false
] | For example: Growth Hormone, IGF-1, Estorgen, Phytoestrogen. | [
"Estrogen is not a peptide hormone, it is a cholesterol based hormone. It does not have peptide bonds that pepsin and trypsin target when they break down proteins. Similarly phytoestrogens are not molecules derived from linkages of amino acids so do not have the correct molecular shape to be targets of proteases li... | [
"Soy contains several molecules that fall into the category of phytoestrogens. They are molecules with a shape similar enough to the estrogen made in our bodies that they can often trick out bodies into thinking they are estrogen. They are not themselves becoming estrogen. Many of them are physically attached to su... | [
"You seem to know your stuff. I'd like to ask a follow-up question. I'm subscribed to a few weightlifting subs. Many users are convinced that soy somehow metabolizes into estrogen. Is that even possible?"
] |
[
"What is the big deal with the determinant in linear algebra?"
] | [
false
] | Im taking differential equations and linear algebra for mechanical engineers in university. Im learning this math but Im not quite sure why the determinant is such a big deal? Surely Ill learn but Im curious. | [
"Linear algebra is a funny thing. It can really be quite interesting if it is taught well, but it is usually taught badly. The reason it is taught at all is because linear algebra is so useful in so many different applications, but too often, students aren't shown this, and are instead expected to learn rules and a... | [
"To expand on this answer: The determinant of a matrix / linear transformation is also a measure of size or scaling factor of the transformation.",
"If you consider the set of ",
" column vectors (or row vectors) of a matrix, then you can construct an ",
"-dimensional parallelepiped (which is the generalizati... | [
"I'll tag into these to give a real example to give some tangibility to these ideas.",
"In engineering, we use matrices (well, tensors) to define deformation of solid under loading. We take the load, apply it to the undeformed solid, and it gives us the deformed shape.",
"These tensors have to have certain prop... |
[
"How exactly is the relation between permittivity and permeability of free space derived?"
] | [
false
] | While studying the Biot-Savart law, I came across the relation between permittivity and permeability of free space. Here it says, "1/ε c = µ " Where 'c' is the speed of light. My question is, how has this relation been derived? And who did it? Why is the speed of light a part of the equation? | [
"In the late 19th century, James Clerk Maxwell collected all the various electromagnetic field equations (from Gauss, Ampere, etc) and compiled them into what are now called ",
"Maxwell's equations.",
" The strength of electric fields depends on the dielectric constant, the strength of magnetic fields depends o... | [
"Eh... The science is spot on. The history could be better.",
"\"The four modern Maxwell's equations can be found individually throughout his 1861 paper, derived theoretically using a molecular vortex model of Michael Faraday's \"lines of force\" and in conjunction with the experimental result of Weber and Kohlra... | [
"Thank you very much! I may need some more help on this topic soon..."
] |
[
"How can trees die of old age, yet successive cuttings of that tree can propagate indefinitely?"
] | [
false
] | null | [
"The reason the trees die is not because of old age, but because they outgrow their ability to successfully deliver the nutrients they need to sustain themselves because of sheer bulk."
] | [
"as i understand it, senescence implies a deterioration, internally, of cellular functions which is not the case with trees not being able to supply nutrients because of size... the cells may still function normally but outside factors inhibit them from doing so leading to death... so i'd say it's more death by gra... | [
"Is there any way to combat this? If you own a tree, can you prevent this?"
] |
[
"How would gravity be affected if the Earth was a cuboid instead of spherical?"
] | [
false
] | Specifically, what would happen if you walked to one of the "edges" and jumped or tried to walk to the other side. Would the oceans just be pulled into space from the tide caused by the moon? Assume the axis is still 23 degrees and set up along two opposite vertexes, orbit is still the same, and moon still exists. | [
"The \"edges\" would be perceived like mountain ridges. The oceans would be convex puddles centered on each face of the cube, far enough away from the edges that tidal forces would not threaten to approach them. In fact, each side of the cube would be 10270 km, meaning the edges would be ~7262 km from the center of... | [
"Of course, the gravity of Earth only allows for mountains to be about 10 - 15 km tall; beyond that height the rock at the base of the mountain is crushed by the weight of the rock above it. So this configuration is unstable based on the mass (gravitational strength) of Earth and the strength of it's rocks (estima... | [
"The Straight Dope had a column about this, and made an assumption that I think you are also making, namely that the person and the cube-shaped Earth are point masses. But they are not, which rather greatly affects the resulting \"heavier/lighter\" behavior over the surface of the cube faces.",
"A ridiculous amo... |
[
"Amplitude, wavelength: Why is the speed of light constant if these are both measures of distance?"
] | [
false
] | null | [
"The amplitude of a light wave is not a distance, it’s an electric or magnetic field strength. The wave shape is the field as a function of space and time, not the path of the wave through space."
] | [
"Thanks. So the wavelength of a light wave is what, exactly?"
] | [
"The distance from one peak to the next peak, or one trough to the next trough."
] |
[
"How do boneless animals have blood?"
] | [
false
] | I know that in humans, blood is formed in bone marrow. How do animals that don't have bones such as sharks or invertebrates, create blood? | [
"Spleens can make blood. They do it in human fetuses before the bone marrow comes online, and they do it in sharks."
] | [
"Red blood cells are formed in marrow, not the entirety of the blood. Only vertebrates use red blood cells. Some invertebrates have freely dissolved hemoglobin (the protein contained in red blood cells) while others don't use hemoglobin at all."
] | [
"What about species of boneless fish and sharks?"
] |
[
"Does a Planck length define the limits to the observable size of a particle?"
] | [
false
] | [deleted] | [
"Let's brush up on dimensional analysis. In other words, suppose I want to know what's the kinetic energy of a particle; I think mass and velocity have something to do with it, and by requiring that the dimensions line up, you get mv",
" as a rough ",
" of what the kinetic energy is. In this case, we can see th... | [
"That paper is highly typical of the kind of questionable theory that people throw around. In the abstract they miss out one of the most important and questionable assumptions they have to make: spacetime is asymptotically flat. I repeat: without experiment, stating with certainty what happens in the Planck regime ... | [
"There is absolutely no other evidence that these scales mean anything.",
"This is wrong, the Planck scale does have a special meaning. You can get them just for dimensional analysis, but it doesn't end in there. In QFT this is trivial because c = h = 1, so the Planck mass scale squared is just the inverse of the... |
[
"Is fat harder to burn, the longer you age with ?"
] | [
false
] | I mean the more time the fat spend in your body, is it more hard to burn it with time? | [
"In reality, adipose tissue is a very dynamic and constantly changing organ, and like bone being \"completely restructured\" every 20 years, a similar statement could be made for adipose. It is likely that the triglycerides stored in one's adipocytes is not the same as they were a week ago due to the constant flux ... | [
"I believe he means, is the fat you've had for a long time harder to burn than fat you've gained recently. "
] | [
"I believe he means, is the fat you've had for a long time harder to burn than fat you've gained recently. "
] |
[
"How does blood transfer oxygen to/take waste from organs if it circulates inside closed vessels?"
] | [
false
] | i'm trying to move beyond the simplistic model of "the blood circulates through the body via arteries and veins, carrying oxygen to and taking away waste from the body's organs", as if they're little UPS trucks...how does the blood stay in the vessels but the oxygen goes in and out? | [
"simply put, by diffusion.\noxygenated blood leaves the lungs via artery, disperse into arterioles then into capillaries, then depending on the CO2 level of the surrounding cell/tissue, RBCs will release some oxygen.. Higher CO2 concentration in tissue then the more oxygen will dissociate from the RBC (very rarely ... | [
"oh and the RBCs are too big to fit through the capillary epithelium "
] | [
"And once you've learned about diffusion, reading about ",
"Oxyhemoglobin dissociation curves",
", the ",
"Bohr Effect",
" and its inverse, the ",
"Haldane Effect",
" will explain why O2 binds to blood in the lungs, but then lets go to get into the tissues (because if Hb bound O2 too tightly, it could n... |
[
"A spinning magnet can induce a current in a conductor, this is how a generator work. But what is the average rotational to electrical energy efficiency of these generator?"
] | [
false
] | null | [
">95% unless you operate it way outside its design range, for large generators in power plants typically something like 98%. They are extremely efficient.",
"article",
", ",
"plots"
] | [
"for large generators in power plants typically something like 98% ",
"Even small machines like 3-400kW generators hit 98.5% efficiency. Bigger machines have lower losses typically.",
"ABB recently made a synchronous motor",
" with 99.05% efficiency."
] | [
"The efficiency of steam drive however....."
] |
[
"Given that the speed of light changes based on the medium the light travels through, is it possible for matter or energy to travel faster than its local light due to moving through some highly refractive or dense medium?"
] | [
false
] | null | [
"Yes, 100% possible.",
"An earthly example: Cerenkov radiation is due to particles from nuclear reactors in water pools which emit particles travelling faster than the speed of light in water. ",
"https://www.iaea.org/newscenter/news/what-is-cherenkov-radiation"
] | [
"Yes it's possible. The slowest light has been recorded at is around 27mph. There are situations where matter will move faster through the medium. The speed of light in a vacuum is the only universal speed limit.",
"EDIT: it looks like 27mph may have been a bad source, 38mph seems to be the consensus on the curre... | [
"Not really, no. That's a common way to describe the phenomenon, but it's really more simple (and harder to understand) than that. The charged particles in a material set up an electromagnetic field that interacts with the photons of light changing the speed it can propagate. No bouncing around, just a change in th... |
[
"Are there any evolutionary similarity between the scales of sea creatures and reptiles?"
] | [
false
] | snakes and fish for example | [
"No, they are fundamentally different kinds of structures. Fish scales grow from the mesoderm inside the skin, and are rather toothlike structures, in some fish (like sharks) containing bone, dentine, and enamel (though your standard fish has thin scales of collagen with a thin layer of harder material on top).",
... | [
"This is the correct response. The fish scale forming from the mesoderm is a distinguishing factor between fish and reptile scale production. Also, as is stated, the same genes that are used to produce hair and teeth in mammals are used in the development of scales. This makes sense seeing as we have a common ances... | [
"Are scales on reptiles related to feathers of birds, due to their classification now. "
] |
[
"What happens when you raise -1 to fractional powers other than 1/2?"
] | [
false
] | I know (-1) is i, but what would (-11/)3 be, for example? And how would it work if -1 were raised to an irrational power, like pi? | [
"(-1)",
" is (1+i*sqrt(3))/2.",
"We can write -1=e",
", and so (-1)",
"=e",
". If we keep in mind that e",
"=cos(t)+i*sin(t), then we can evaluate many of these exactly as in the case (-1)",
". ",
"There is some subtlety to this and the choices we make and how you choose roots. For instance, we can,... | [
"The n",
" roots of -1 are a collection of n points spaced evenly around the unit circle in the complex plane. For example, the only number which yields -1 when raised to the 1",
" power is -1. There are two numbers which yield -1 when raised to the 2",
" power: i and -i, diametrically opposite on the unit ci... | [
"You get an irrational number, which has an infinitely long decimal expansion but is not an \"infinite value\".",
"-1",
" for example, is -0.90268... - 0.430301...i. Both the real and imaginary parts are irrational."
] |
[
"Could you polish two large stones so well that they would have low enough friction to slide against each other \"effortlessly\"?"
] | [
false
] | null | [
"And this is why a person can still get squashed by big rocks floating around in a zero G environment: inertia is a property of mass and is independent of weight."
] | [
"You can polish them pretty well and get a very low coefficient of friction, but there is no such thing as \"effortlessly\" as in absolutely zero friction (one exception, I'll come back to that). The reason is that everything is made up of atoms and molecules and when two objects, polished rocks or whatever, are in... | [
"To add: even if you polished them somehow down to zero friction, a stone still has mass so a large stone still has a large mass. So to move the stone, even if it's on a zero friction surface still means accelerating that large mass, which would require some input of force, which would (seemingly) be considered \"e... |
[
"How did eusociality evolve in Hymenoptera (bees, ants, and wasps)? Did it occur multiple times or just once?"
] | [
false
] | I know that both ants and bees are descended from wasps. So was there a social wasp common ancestor that gave rise to bees, ants, and modern social wasps like yellowjackets? Or did all these groups evolve colony behavior independently? Eusociality in hymenoptera is so complex I have a hard time imagining how it could e... | [
"Yes, it's evolved multiple times in the group (IIRC something like 10 times, much more frequently than any other group). There are several factors that make it relatively easy to evolve in hymenoptera specifically. This paper discuses some of them ",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3279739/",
... | [
"Eusociality has definitely evolved multiple times within Hymenoptera. To start with, let's consider how this is actually defined. True eusociality has several requirements, including overlapping generations living together, concentration of reproduction into a subset of a colony (often a single individual), and ... | [
"What about naked mole rats I'm pretty sure they are the only eusocial mammals, but then again I used to think that moose was another name for deer, so I may be wrong"
] |
[
"I have a question about super string theory, or M theory. I thought you guys might be able to help."
] | [
false
] | [deleted] | [
"Ah... this is a really important distinction and miscommunication between us then. I too don't really think that \"theory\" is an appropriate word here. Model perhaps. Idea. Scientific hypothesis, framework, something. ",
"But let's also remember what a theory ",
". It's a way of describing a bunch of separate... | [
"Try this",
".",
"The ten-dimensions thing is rubbish. It's not even sufficiently similar to science to be called pseudoscience. It's merely sciencey."
] | [
"Look, I'm not sold on string theory myself, but this is way over the top. They have a theory that works mathematically, even if it must be massaged a bit. There are tests proposed for it, but we just don't have the technology to build them. Perhaps after they theorize a bit more they might have something that is t... |
[
"Diarrhea - What is happening in the body?"
] | [
false
] | I am very curious to know what the body and specific organs are doing when diarrhea is present. Many results on google give reasons and causes but what is the body doing or not doing, to make this happen? | [
"If you drink coffee (most of us do), and ever added cream or milk but ",
" stirred it, and watched it slowly dissolve into the coffee, you're observing a process known as diffusion. Substances with a higher concentration tend to diffuse to a lower concentration until both substances are balanced, in this case, ... | [
"Diarrhea can be caused by a number of things, from bacteria to viruses to tons of other things, such as illness or medication. Physiologically, after passing through the stomach, water and nutrients are absorbed from your partially digested food via the intestines to help solidify it into stool. Generally, diarrhe... | [
"To summarize there are four different broad mechanisms of diarrhea: (More depending on the level of detail you require but let's make it four for the sake of simplicity)",
": ie stimulant laxatives like caffeine, Senna, and Bisacodyl can cause this. So can opiate withdrawal.",
": ie Cholera (kills through dehy... |
[
"How effective are nasal rinses, really, in reducing sinus problems?"
] | [
false
] | They all claim that by regularly cleaning out your sinuses you will reduce the number of sinus infections, problems from allergies, etc. Is this backed up by actual research? And are these claims regulated? | [
"It's well accepted that they reduce the symptoms of certain conditions when used with buffered hypotonic normal saline. ",
"Here",
"They're used to alleviate symptoms more than treat a condition. ",
"They are sometimes recommended post nasal surgery as well.",
"Long term continual use however ",
"may be... | [
"Amebic encephalitis is a bad disease, but this can be easily prevented by boiling the water for sinus rinses. I recommend sinus rinses based on Teedy's data below; for some people they really seem to help. Especially around here, where it's particularly dry, it is helpful to get stuff hydrated and moved along."
] | [
"RE: Amoebas",
"Doesn't matter if you're in a hot or cold country. It's a function of having amoebas in the water, and simply introducing water with the amoebas to your nasal cavity will allow them to burrow along your olfactory nerve into your brain and go to fucking town. ",
" infections turn up in the US a... |
[
"If light speed isn't changed by the speed of the point of production, in the same amount of time, does one side of a light receive greater amounts of photons than the other side of the light?"
] | [
false
] | Theoretically, If you were to go half the speed of light, with a bulb lit on the top of your craft, then measure the amount of light in front of and behind the craft for the same amount of time, would the backside receive a lower count of photons? Edit: you guys are awesome | [
"Yes. Light going directly backwards or forwards will remain so in any frame, however light going mostly up and little forward in one frame can be going mostly up and a little backward in a different frame."
] | [
"The other respondents have some disagreement. Allow me to clear it up:",
"So you're in a spaceship traveling at half the speed of light relative to some other reference frame. You've got a bulb on top of your craft. If ",
" (isotropic), because in your reference frame you're at rest, so it's no different than ... | [
"No. According to relativity, any constant-speed reference frame is the same as any other from the point of view of any experiments done within that reference frame. Therefore, the result of this experiment at half the speed of light will be the same as the results if done at rest. Assuming a symmetrical bulb, b... |
[
"What's the significance of a eutectic/peritectic/eutectoid point and composition?"
] | [
false
] | It sounds an awful lot like an academic pursuit vs having any practical application. After all, a eutectic point is where liquid turns directly into two solid phases. I can't see any use in that because it's only the lowest melting point which seems like something one would want to avoid. | [
"This is actually a very very important property of a mixed phase system. If I take a rock made of two minerals and start heating it up, at what temperature do I get the first melt, and what is the composition of that melt? The answer is \"at the eutectic.\"",
"Similarly, let's say I want to distill ethanol from ... | [
"Some eutectics are useful ",
" you want a low melting point, e.g. traditional tin-lead solder, or other compositions used as a replacement for such. ",
"Other phase transition points are useful for the effects they can have on the microstructure of a material. The eutectoid transformation of ",
"austenite",
... | [
"Eutetic compositions and Euctectoid temperatures are very important in any process where melting or freezing of a two or component system occurs. This could be a casting process, or heat treatment process. Understanding the eutectic compositions and temperatures will determine the phase compositions and phase crys... |
[
"[Engineering] How efficient are computer processors?"
] | [
false
] | From what I understand, heat generated by electronics is caused by it not being 100% efficient, better efficiency = lower heat. Please correct me if I'm wrong. But knowing that computer and graphics processors can reach up to 100°c before failing (or throttling). How efficient are processors really? I know high quality... | [
"When a power supply is rated as 85% efficient, what they mean is that 85% of the energy that goes into the power supply makes it to the components that it is powering, and ~15% is released as heat.",
"CPUs/GPUs/etc don't work by directing the energy elsewhere, so it's not clear how you would rate their efficienc... | [
"It all depends on what you mean by efficiency, generally we measure it by energy in to energy out but a processor doesn’t output energy, at least not energy we care about. Therefore you could say its efficiency is 0% as there is no output power or 100% as all energy is used to calculate. I guess you might find a m... | [
"Well, not exactly 100% heat dissipated in the CPU itself. Some tiny current does flow over the data and address lines to peripherals to dissipate heat elsewhere. There's also RF emissions."
] |
[
"Can computers keep getting faster?"
] | [
false
] | or is there a limit to which our computational power will reach a constant which will be negligible to the increment of hardware power | [
"It depends what you mean by faster. There are many different measurements. I will focus on CPU speed here, but computer speed is a chain of many things, where the weakest link will cause a slowdown of everything.",
"The CPU: Here over the last 50 years processors have gotten vastly better at processing instru... | [
"No, quantum computing, in itself, has no effect on speed. What it does is make some algorithms available that normal CPUs can't natively execute. These new algorithms require less operations to arrive at the same result, meaning that specific problem gets solved faster. It does not mean that the processor is any f... | [
"I think the other answers have been overly-specific so far. Let me try. In short: yes, for quite some time. (As others have said, there are limits to density, but I don't think that was your question.)",
"Many answers have already talked about standard things like transistors, cores, and clock rates and blah bla... |
[
"Are animals born in litters genetically similar to twins compared to single birth animals?"
] | [
false
] | Say a cat gives birth, are the kittens in the litter twins by genetics like in humans? And would a second litter of kittens be genetically similar to siblings with the first litter? Apologies if I described it poorly. | [
"Usually not, they mostly develop from different eggs so they are fraternal twins not identical.",
"There have been cases found where splitting of an egg gives rise to identical twin animals in a litter. ",
"https://curiosity.com/topics/scientists-have-confirmed-the-first-identical-twin-puppies-and-its-a-big-su... | [
"So many variables. Do the kittens between the litters have the same father? Do the kittens in the same litter have the same father?",
"Cats are capable of superfecundation and superfetation, which means that kittens in the same litter can have different dads:",
"\"A litter of kittens born to a single mother ca... | [
"Thanks for the answer"
] |
[
"What is a topological insulator?"
] | [
false
] | [deleted] | [
"I don't have time for a full response with my own personal input, but see below:",
"The Hasan-Kane review article is a well-known one, and at the end of the intro section it references several of the other reviews: ",
"http://rmp.aps.org/abstract/RMP/v82/i4/p3045_1",
"This article in Physics Today is also ni... | [
"Mathematician's perspective here. When thinking about geometry, you can think globally and locally. An example of thinking locally is thinking about the metric of a space at a point. It's quite intuitive to think about physics in terms of locally defined quantities in some geometric space.",
"However there is a ... | [
"I find that ",
"this brief intro",
" to topological insulators is generally well-received when I've referred it to others in the past."
] |
[
"How does the STAR detector at the Brookhaven Lab detect?"
] | [
false
] | I'm not sure how specific to be, this is a fairly new concept to me. For instance, what exactly are they looking for with the experiment | [
"Essentially, STAR is a detector designed to see what comes out of heavy ion collisions at the RHIC accelerator at Brookhaven National Lab. The accelerator sends large nuclei, such as gold atoms that are stripped of all electrons, around the accelerator's ring at nearly the speed of light. There are two \"beams\" ... | [
"Thank you, very helpful!"
] | [
"Are you interested in which types of particle detectors are used in the STAR experiment, how the detectors are arranged, and what is the operating principle of each detector type?"
] |
[
"If phytoplankton contribute to half of the global oxygen output, has declined by 40% since the 50's, why is atmospheric oxygen not dropping noticeably?"
] | [
false
] | The global phytoplankton population has been found to have and are dropping by 1% per year, an alarming rate for a population of plankton that is contributing to 50% of the global oxygen output! Yet, by 0.7% of atmospheric oxygen in the past 800,000 years and can't figure out why that is so and calling it "atmospheric ... | [
"So there are a couple of factors at play here. Atmospheric O2 is decreasing over time, as can be ",
"seen in this chart from Scripps",
" (compare to the ",
"Keeling Curve, which monitors CO2",
"). This is largely due to burning of hydrocarbons, a general form of which could be given as CH+O2->CO2+H2O. Whil... | [
"Would lowered O2 levels be more detectable at altitude or ground level. I have heard reports of pilots experiencing hypoxia symptoms which could be due to lower O2 levels at altitude.",
"Would weather pressure systems have an impact with O2 levels e.g. a low pressure system implies reduced air density combined ... | [
"I have heard reports of pilots experiencing hypoxia symptoms which could be due to lower O2 levels at altitude.",
"This is an effect of the altitude in general. The air is thinner if you go up. It has nothing to do with changing O2 concentrations, these are negligible over human timescales.",
"And what about C... |
[
"Would it ever be possible for humans to have gold-colored eyes (like cats, owls, wolves, bald eagles, etc.)?"
] | [
false
] | I am wondering if it would ever be possible, through a genetic-engineering perspective, for humans to have the gold-colored eyes that other animals have. Let's say you have a futuristic culture in which designer babies are the norm, and diseases have been all-but-eradicated in this better "breed" of human which has res... | [
"This may not be the best answer, but since you havent gotten any responses yet, I dont think there is much known about the genes underlying eye colour in animals, there may be a little known about cats perhaps, but even in humans we dont know all the genes and mutation involved in eye colour determination. I think... | [
"There are at least two genes that influence eye color in humans, which is the explanation for why people with different forms of albinism might have blue eyes (only one pigmentation gene is coloring the eye) or pink eyes (neither of the genes that supply color to they eyes do so, which allows the underlying blood ... | [
"Thanks a lot! You've really helped me! :)"
] |
[
"Why aren't all known archaeological sites excavated?"
] | [
false
] | I've been reading a book about sites in County Clare (Ireland) that mentions that there are many sites that are not excavated, and that got me wondering about why. Is there a shortage of people capable of it? I'd imagine a new pyramid in Egypt would have people scrambling to unearth it as fast as possible, so why are t... | [
"You bring up a lot of good reasons, but I'd like to add some. Excavation destroys/damages the thing being excavated. Excavation methods get better over time, so that they become less destructive and yield more information. So by not excavating a site now, we are preserving it for more capable future archaeologists... | [
"You bring up a lot of good reasons, but I'd like to add some. Excavation destroys/damages the thing being excavated. Excavation methods get better over time, so that they become less destructive and yield more information. So by not excavating a site now, we are preserving it for more capable future archaeologists... | [
"Thanks!"
] |
[
"Why does acetone cause things to cool down so quickly?"
] | [
false
] | I was cleaning a spray gun at work with acetone yesterday, and noticed the metal was much colder than room temperature when I was done. It also makes my hand much colder when I get it on me. It's been a while since chemistry. How does the acetone manage to suck so much heat out so quickly? | [
"Acetone has a high vapour pressure at room temperature. This means that it tends to vaporize rather easily.",
"Vaporization is an endothermic process - it requires heat to turn something from the liquid to gas phase. Therefore when something vaporizes, it sucks heat from its environment, so the temperature lower... | [
"To add, this is the process by which sweating works. The sweat evaporates, taking your body heat with it."
] | [
"/u/rupert1920",
" is totally correct but fails to explain why vaporization is endothermic. ",
"Let us imagine a collection of acetone on a surface. Temperature is proportional to the average kinetic energy of the particles. The molecules that evaporate first are the ones with the highest kinetic energy (that i... |
[
"Have we learned anything new from mars that we didn't already know before landing there with a rover?"
] | [
false
] | null | [
"Of course we learned things about the planet from deploying rovers. Getting a vehicle with cameras and various sensors on the ground gives a wealth of information that cannot be garnered from Earth or even from an orbiter.",
"Probably the most significant data is that relating to water on Mars. Spirit and Opport... | [
"Two main reasons, is there a way for us to extract the water for use in an eventual human settlement? Both for drinking and power generation with fuel cells. Two, if it used to have lots of water and now doesn't, what happened? Could the same thing happen to earth? "
] | [
"Thanks for including Spirit and Opportunity. I've seen posts discussing \"the rover\" like Curiosity is alone over there. I love them all."
] |
[
"How might a bacterial cell control copy number of its plasmid?"
] | [
false
] | To be a little more specific, if I put a plasmid with a gene (urease) that's normally under some pretty specific Nickel dependent (NikR) regulation instead under a constitutive T7 promoter, and the cells are making too much urease for their metabolic aims, does selection have any diversity to work on with regards to th... | [
"The plasmid number won't be regulated, and your gene will only be regulated by whatever regulators your plasmid carries (e.g. Lac operon promoter). Plasmid number, as far as I know, is largely determined by the affinity for the DNA Synthase complex for its origin of replication and the bacteria's doubling time. ",... | [
"Not true, plasmid copy number is absolutely regulated. While your promotor will control transcription for that gene or operon, plasmids have their own origin of replication (similar to oriC, the chromosomal origin). These origins of replication will also control the frequency of replication for that entire plasm... | [
"I don't think the origin of replication has protein promoters, but I might be wrong. I mentioned that plasmid replication is affected by the bacteria's affinity for the origin of replication, which sounds like the regulation you're talking about. In that case, it affects the copy number, but the bacteria can't reg... |
[
"Why is the Earth's crust split into Tectonic plates?"
] | [
false
] | Whenever I have learned about this topic at various levels of education, we have simply been taught that the Earth is split into numerous tectonic plates, but WHY is this the case? Surely the earth's crust could be one joined together thing that moves as one on top of the mantles convection currents? | [
"You've erroneously assumed that all of the earth's crust is homogeneous, which is not the case. A fundamental driving force for plate tectonics is density contrasts, between the primarily basaltic, denser ",
"oceanic crust",
" and the variable composition, but lighter ",
"continental crust",
" and also bet... | [
"Surely the earth's crust could be one joined together thing that moves as one on top of the mantles convection currents?",
"http://upload.wikimedia.org/wikipedia/commons/2/27/Oceanic_spreading.svg",
"The problem here is that the mantle isn't all moving in the same direction. The upper layer of the mantle moves... | [
"As well as what ",
"/u/Sevrael",
" said, tectonic plates aren't fundamentally different from just rocks on the earth's crust. They are only classified as distinct individual pieces because they are very big, and surrounded by very big faults. And they don't really change in shape as quickly as smaller rocks."
... |
[
"Is it more environmentally friendly to get a real xmas tree from a tree lot every year or use the same artificial tree each year?"
] | [
false
] | null | [
"Hi blankiamyourfather 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 ... | [
"Earth sciences"
] | [
"'Earth Sciences'"
] |
[
"Why don’t vaccines carry over genetically?"
] | [
false
] | Just curious with everything going on why vaccines don’t essentially pass down to our children genetically if we’ve been immunised. Is it purely because we didn’t genetically start with that or purely down to the synthetic (well atleast not made naturally by the body) nature of the vaccinations? | [
"1) Vaccines do not alter your genetic information, i.e. those in the form of RNA (the new ones, because up until today they were protein based) do not integrate into the genome.",
"2) even if RNA vaccines could integrate into the DNA, you still wouldn't pass them on because vaccinations are injected into somatic... | [
"Others have explained that vaccines don't alter the genetics that you can pass down. However, it's not just what vaccines do, but none of the adaptive immunity can be passed down genetically, even though biologically speaking, it would be great if it could. Imagine being immune to smallpox or the plague and all of... | [
"No. Our bodies can only pass down genes that were passed to them. They do not form new dna based on what the immune system learned. However natural selection would form a disease resistant species, if not for modern medicine. It would just be a sad process of everyone dying from disease, besides those with genetic... |
[
"How high of a temperature would you theoretically need to break any combination of molecules apart from each other into their single elements?"
] | [
false
] | null | [
"As Qwerty222 said, there is certainly a question of molecular bond strength. It should be pretty easy to set an upperbound on this, however.",
"For covalent molecules, (excluding network solids) I'd suspect something on the order of 1500K in the absence of oxygen.",
"For network solids, maybe 3000K? This is a ... | [
"Depends on the molecule's bond strength, and whether or not the reaction is exothermic. ",
"Thermal Decomposition",
"."
] | [
"You're technically correct, but if you're implying that some bonds cannot be broken by adding heat just because their formation is endothermic, then that's wrong.",
"Unless the system is at very high density/pressure, free atoms will have a higher entropy than any bonded configuration; a sufficiently high temper... |
[
"How does my phone/laptop/device know how much charge is left on the battery?"
] | [
false
] | How does a device know how much charge is left on the battery? As in what is the mechanism that is used to extract and convey this information? | [
"At the full charge, the battery will have a certain voltage. As it is used, the voltage begins to drop, most likely the computer reads that voltage drop and displays it in a way that is useful to us."
] | [
"Yes it would have the same voltage as a new battery, albeit for a shorter amount of time. "
] | [
"A follow up question: would that mean that fully a charged older battery despite having a reduced charging capacity (or a memory effect) puts out the same voltage as a brand new battery at full charge?"
] |
[
"How would an observer view the universe if it were at the origin of the big bang?"
] | [
false
] | According to my knowledge the universe started expanding near the speed of light. When taking relativity into account wouldn't the observer see the Universe as a relatively small place due to Length-contraction? Wouldn't the observer think a lot less time has passed than what we humans on earth consider to be slightly ... | [
"Metric expansion is ",
" the same as motion. For all intents and purposes you can treat things as being at rest with space expanding between them. So metric expansion doesn't involve length contraction or time dilation. It's the same reason why sufficiently distant galaxies would appear ",
" they're moving awa... | [
"We have found solutions of space-time curvature that would be warped in such a way as to allow faster than light travel (on a global scale) while maintaining slower than light travel locally. The problem is that these solutions are also impossible to build. Not just technologically difficult, they require forms of... | [
"Thanks for this reply! So in theory if this process of metric expansion could be reversed or warped could we achieve \"faster than light\" travel under the laws of current physics?",
"Extra question: What force does the expanding of space? At öeast in conventional physics objects with mass should pull themselves... |
[
"As the light of more stars reaches the earth, will the night sky become brighter and brighter over time?"
] | [
false
] | Looking forward billions of years, if someone was able to look up at the night sky from earth (lets assume its still here), will there be some point in the future where the night sky is saturated with light? | [
"The opposite will happen, actually. ",
"Space is expanding faster than the speed of light. Except for a small bubble around the milky way, galaxies will move outside the observable universe until there are no stars left except ones in the milky way. According to the big rip theory, eventually, even those will go... | [
"The galaxies aren't expanding. The space between them is. Or, if there is a repulsive force within the galaxy, it isn't nearly strong enough to overcome the attractive force of the galaxy that binds itself together. The repulsive force (we call it dark energy because we have no idea wtf it is, only that it exists)... | [
"Because we are in the milky way. The expansion of the universe only has an effect at large scales - larger than our galaxy. "
] |
[
"Why India’s Chandrayaan-2 is taking 6 weeks to reach Moon and land their lunar lander, while Apollo missions typically landed astronauts on the moon in about 6+ hours?"
] | [
false
] | [deleted] | [
"After being placed into a 45,475 × 169 km ",
"parking orbit",
" by the launch vehicle,",
"[47]",
" the Chandrayaan-2 spacecraft stack gradually raised its orbit using on-board propulsion over 22 days. In this phase, one perigee-raising and five apogee-raising burns were performed to reach a highly eccen... | [
"More in depth explanation:",
"The Oberth effect: in layman's terms it is more efficient to do maneuvers when deep in a gravity well. So the closer to the Earth the rocket it when it has it's engine on the more efficient it will be and it will require less fuel. This effect applies to both Chandrayaan and Apollo ... | [
"Good answers here, just wanted to add:",
"It took a ",
" longer than 6 hours to land astronauts on the Moon. Apollo 11 took 52 hours to get into lunar orbit, and a total of 110 hours from mission start until astronauts landed on the Moon.",
"The fastest any spacecraft has reached the Moon was New Horizons, w... |
[
"Do Photons get trapped behind your eyes when you close them?"
] | [
false
] | [deleted] | [
"Since your body, or anything for that matter, is constantly emitting ",
"thermal EM radiation",
" (photons with wavelengths below the wavelength we can see), the answer is kinda weird. When you close your eyes, there are tons of photons of these lower energies propagating around the inside of your eyeball beca... | [
"All electromagnetic radiation, including visible light, x-rays, and all those other waves, are made of photons, differing only in frequency"
] | [
"If you close your eyes, you can tell if the light is on or off."
] |
[
"Why do we have to kill a horse when it broke its leg? What is the difference in biological processes between man and horse in bone mending?"
] | [
false
] | Edit: Thanks for popping my gold cherry kind stranger! | [
"Hi there.",
"The biological processes of bone healing are the same in both horses and humans. The problem is in their weight and behavior. And it depends on the location of the fracture whether or not the horse may need to be euthanized.",
"When humans break bones, they can take weight off by sitting down, usi... | [
"Actually, there's one other detail you forgot to mention, which is that horses also cannot afford to lie down for prolonged periods of time as it messes up their internal organs. ",
"This is problematic as not only will having them support themselves on 3 legs cause damage to their intact legs, but you can't lie... | [
"Also, induction and emergence (going into and coming out of anesthesia) of horses is very scary and they can hurt themselves during the process. ",
"Their bones are huge, and the hardware to fix them has to be specially made, the hardware for humans doesn't fit their bones. ",
"Bones are harder than the surgic... |
[
"What would humanity gain from increasing funding for space exploration?"
] | [
false
] | null | [
"Is \"awesomeness\" an acceptable answer?"
] | [
"Survival."
] | [
"The Sagan influence in me feels compelled to add that there's the fact that sending people to space is also freakin' awesome."
] |
[
"How Does Hawking Radiation Cause a Black Hole to Lose Mass?"
] | [
false
] | I am not a formal student of physics, but I am an engineering graduate and have several courses in fundamental physics and thermodynamics under my belt, and I have a layman's interest in theoretical physics. My understanding of Hawking radiation is that it occurs due to virtual particle pairs spawning near the event ho... | [
"Virtual particles are a calculational tool. They are not something that can ever be observed (they don't even have the correct physical relationship between their energy , momentum, and mass). What you have outlined above is one way (sort of) to describe the first calculation that led Hawking to predict the evap... | [
"Hawking radiation is formed from the annihilation of pairs of particles at the horizon. ",
"This is simply incorrect."
] | [
"Hawking radiation is formed from the annihilation of pairs of particles at the horizon. ",
"This is simply incorrect."
] |
[
"Halogen Heaters and Basil Plants."
] | [
false
] | [deleted] | [
"Unless it's ridiculously cold in your house, the limiting factor here is going to be light usable to the plant - photosynthetically active radiation. A halogen heater puts out a very small amount of PAR. The best thing you could do* is keep it near a sunny window and train several CFL lamps on the leaves (quite ... | [
"not saying it isn't appropriate here, but may I also suggest ",
"r/gardening",
"? They may have good tips."
] | [
"You can make a cold frame (mini greenhouse) and by some plant growing lights. As long as it doesn't go below freezing it ",
" be fine. Alternatively,Basil is very easy to grow, you could take a cutting and place it in a sunny window and it will survive the winter. "
] |
[
"Why do we sometimes have blurry vision when we wake up?"
] | [
false
] | Is this something that only happens to people with glasses, or is this an occurrence for most people? EDIT: Sorry, if this came off as anecdotal. | [
"Eyes have some amounts of oil and mucus on them, and when adequately moisturized by the tear ducts we see fine through it. When tears dry up (which can happen overnight), the oil and mucus can appear somewhat blurry. "
] | [
"Tear ducts are what drains the tears, not what produces them. The lacrimal gland makes tears."
] | [
"I think you're referring to ",
"http://en.m.wikipedia.org/wiki/Rheum",
"It's a mucus that is meant to lubricate your eyes that doesn't get washed away while you sleep."
] |
[
"There is a redditor who attended the CERN OPERA briefing doing an AMA. Can we get a regular contributor to r/askscience to take a look and do a little peer review? (X-post link inside)"
] | [
false
] | [deleted] | [
"His summary seems reasonable. He's likely some sort of physics student (possibly grad). The results are almost definitely an unknown source of systematic bias, and should continue to be assumed so (unless you are a particle theorist who wants something fun to ponder about) until more independent experiments conf... | [
"Well, I kind of disagree with the 'doesn't disprove relativity' angle. I see where you're coming from with it, but I'm not sure it's a good way of expressing it. The point here is that SR is so ",
" ingrained in current theory, and has made so very many correct predictions (from anti-particles to QED in physics,... | [
"Since this result is rather blatantly at odds with SR, it means something must be wrong with some of our basic postulates. And it seems far from obvious which one(s) you could invalidate and still rescue most of what we know to be true. Who can really tell the scale of the theoretical ramifications?",
"I think t... |
[
"Why are there so many research stations on the Antartica and what are we actually researching?"
] | [
false
] | null | [
"You can get a lot of ",
"climate history from ice cores",
", and the dynamics of ice sheets are important for estimating future sea level rise in response to warming.",
"The waters around Antarctica have unique biology.",
"There is ",
"uniquely non-turbulent clear air for astronomical purposes",
".",
... | [
"To add two more:",
"The ",
"dry valleys are used as analogues of early earth",
".",
"There are ",
"extensive efforts",
" to collect meteorites in Antarctica (basically because they are easy to pick out on the ice)."
] | [
"It's the continent least contaminated by human activity and much of it is frozen so there's unique opportunities to discover aspects of planetary,climate, and biological history. Think of how useful Pompeii was for historians since it was like a city frozen in time"
] |
[
"What are the physiological adaptations for hot climates?"
] | [
false
] | null | [
"Probably more than you wanted to know",
"Summary: Your sweat becomes more dilute and you sweat more and start sweating faster, your body water and plasma volume increase and you become thirstier, your metabolic rate and heart rate decrease, your resting core and skin temperatures drop, and you start producing he... | [
"Some way to exchange heat with the environment. For example primates sweat, other animals like hares increase their surface area for heat exchange and others simply tolerate higher body temperatures or stay underground/in shade during the day."
] | [
"IN hot climates, maintaining body heat is not a problem(the surrounding helps in that aspect), but dissipating it is the main concern",
"Increased melanin production, oily skin due to sweat to prevent the body from getting overheated(yes it is very common among people who live in the tropical regions). If you ar... |
[
"Why is coulomb not a fundamental unit?"
] | [
false
] | I know that Ampere is the fundamental unit in Electricity, but doesn't it make more sense to have coulombs to be the fundamental unit? | [
"It's easier to measure an ampere precisely than it is a coulomb."
] | [
"...you take angles counterclockwise from the x axis."
] | [
"This is the correct answer. However, it terms of what ought to be a fundamental unit, the Coulomb certain should be because the ampere is a measure of the amount of electric charge passing a point in an electric circuit per unit time with 6.241 × 1018 electrons, or one Coulomb per second constituting one ampere. S... |
[
"Double Slit Question"
] | [
false
] | In the experiment, they found (correct me if I'm wrong) that the same principle applies to both photons electrons, i.e., an interference pattern is created so long as the path of the projectile is not observed. My understanding is that the interference pattern is created by the interference of the probability wave of t... | [
"The general trend is that, as things get smaller, the quantum stuff (wave functions and whatnot) becomes more applicable. As things get larger, the quantum effects are still present, but classical behavior eventually drowns out the quantum effects. So, yes, after some point, you'd only see two lines at your detect... | [
"The interference pattern for buckyballs",
"."
] | [
"Last I heard, we don't know the cutoff where quantum effects stop. We can actually do the double slit experiment with large things like buckyballs, and even clouds of Bose-Einstein condensate."
] |
[
"Will a organ that was donated from a younger person to an older person help minimize the aging process? Also, will the organ age faster due to the already aged organs around it?"
] | [
false
] | null | [
"Transplantation isn't what you think. It doesn't restore a person. It's a kludge. But your thinking is common because the media's reports on transplants are biased and rarely discuss the negatives.",
"The organ is damaged by the surgeries and by being outside a body. The recipient must take pills for the rest of... | [
"I remember when ",
"Robert Altman was awarded a lifetime achievement Oscar in 2006",
". In his acceptance speech, he revealed that he'd had a heart transplant from a woman in her 30s, 10 years earlier, so he thought he had 40 years or more left. He did not survive the year (he died of cancer). Heart transplant... | [
"So... We make clones and then store them on an island until we need an organ."
] |
[
"Why are there so many volcanic eruptions recently? Are they somehow connected or is it a coincidence? Or is it just new media coverage?"
] | [
false
] | null | [
"The current level of activity is normal. On average, there are usually ~20 volcanoes in some stage of erupting at any given time. The recent news worthy eruptions (e.g. Hawaii and the recent one in Guatemala) are not connected. So the short answer it's just the coverage and/or the fact that these two eruptions are... | [
"I think the ",
"Clustering Illusion",
" may be an answer to this question, at least in part."
] | [
"Yes, ",
"apophenia",
" in general is a good explanation for lots of perceived patterns in natural phenomena, and especially those that get asked about here on AskScience. Not all patterns and apparent clustering in things like earthquakes, volcanoes, etc are devoid of meaning (e.g. aftershock sequences are goo... |
[
"Are there any successful attempts to create a substance that is made up entirely with antimatter particles?"
] | [
false
] | null | [
"Yes, as long as you consider a small amount of antihydrogen-atoms as being a substance. CERN has successfully kept these antiatoms around for about 16 minutes. Here's the press release from 2011: ",
"http://press.cern/press-releases/2011/06/cern-experiment-traps-antimatter-atoms-1000-seconds",
"."
] | [
"No. The (unfounded) concern was that, at the extremely high energy densities probed by CERN, microscopic black holes should be created, as any amount of energy/mass packed into a sufficiently small space will collapse into a black hole. However, Stephen Hawking's greatest contribution to physics was arguably his d... | [
"It was his consideration of what happens when a ",
"virtual particle pair",
", a consequence of quantum mechanics, comes into existence at the event horizon of a black hole. If one member of the pair goes into the black hole and is trapped while the other escapes, then energy conservation if violated because n... |
[
"What's the smallest amount of collected atoms that can be detected by the human eye (not necessarily molecules because molecules can vary in size)? like a grain of sand, or.. A tiny piece of aluminum or gold."
] | [
false
] | null | [
"best possible human ",
"visual acuity",
" is around 20/10 (or 6/3); with this acuity you can discriminate between details or spots that are just one half arcminute of visual angle across (and separated by the same distance, so the limit of resolution is 1 discrimination per arcminute). you're going to need two... | [
"That is a linear measure, assuming your 150k atom diameter, you are really looking at around 10",
" atoms for a minimally detectable sphere."
] | [
"Assuming your length of 15um being the smallest diameter particle visible is correct(personally I can see 45um particles in the lab i work at), and if we work with a common opaque material, in this case common graphite, we can calculate the number of atoms.",
"As a single layer(graphene), its basically transpare... |
[
"Is there some sort of library for DNA of every living creature?"
] | [
false
] | It occurred to me that since cloning technology is becoming more advanced, why don't we keep an archive of DNA samples of every currently living creature so we could resurrect a species if it goes extinct? We might already, but I'm just curious. | [
"There are a few places like this, although I know of none with complete repositories, nor can I find reference to any such institution. It's also unlikely that we'd be able to save DNA samples from every \"creature\" (more on this later, though).",
"The American Museum of Natural History in NYC has put forth a ... | [
"I think he means do they have an archive of the actual physical genomes. Maybe in cryogenic storage of something. As far as I'm aware there is no big multi-species storage location. But for individual model organisms there are certain places with thousands of strains of that organism (e.g. mice, drosophila, zebraf... | [
"More or less, Yes. It's called GeneBank and it's run by the NCBI which itself is part of the NIH. It's a database where they accept whole genome data from labs.",
"\nHowever, most of the database is composed of \"popular\" organism like human and species used as model organisms like rats, microbes, Arabidopsis... |
[
"Why has there been no vaccine produced for SARS even though the first outbreak was in 2003, or MERS which was identified in 2012?"
] | [
false
] | Does the fact that we don’t have a vaccine for either illnesses despite 17 and 8 years having passed reflect on the likelihood of finding a vaccine for the current pandemic? | [
"For SARS, experimental vaccines were made and seemed to be reasonably safe and effective in animal models. For example (this is not the only one) ",
"Immunogenicity, safety, and protective efficacy of an inactivated SARS-associated coronavirus vaccine in rhesus monkeys",
" ",
"MERS hasn’t progressed as far, ... | [
"Because we didn’t need those vaccines to stop the outbreaks. SARS and MERS are not very infective, and patients can’t infect others until they have shown symptoms for a few days already. This means that for SARS governments just put all patients in isolation, and for MERS (which is ongoing, and transmitted via inf... | [
"And two more things: firstly, it’s unlikely that a vaccine for those would be effective against corona, although it is possible; and secondly, it doesn’t reflect the likelihood of a vaccine for corona. It seems extremely likely that corona will become a seasonal illness, and a lot of attention will thus be devoted... |
[
"Why is the FYA gene not present in Africans and why is it important?"
] | [
false
] | [deleted] | [
"The FY genotypes (FYA, FYB, FY3) encode slightly different variations of a protein present in the membrane of our red blood cells. ",
"It's important only so far as because this protein also happens to be the receptor that is recognized by ",
", the parasite that causes malaria. So, if you lack the FY antige... | [
"To answer the first half of your question, the Fy glycoproteins are sticky little membrane proteins that are expressed on the surface of many cell types including immature red blood cells (reticulocytes), mature red blood cells (erythrocytes), epithelium of blood vessels, lung alveoli and parts of the brain. It ac... | [
"Came here hoping to see rational explanations for genetic differences. Did not disappoint.",
"Thanks for being askscience, and not worldnews, where anti-African opinions appear to be rampant. To the OP, you could also use the same conceptual situation to explain the difference between lactose tolerance in Europe... |
[
"If the universe is infinite, how can it expand?"
] | [
false
] | If the universe is infinite, how can something infinite expand? Doesn't the word expand implies that the thing that expands is finite? Also, if the universe is expanding, what would happen if I travel faster than the universe expanding rate for long enough in one direction? | [
"We have rejected the infinite universe theory a long time ago, by accepting the idea of a big bang.",
"Au contraire, the most commonly used model for the Universe implies an infinite Universe. It's called \"flat Lambda CDM\"."
] | [
"Sorry, but the size and cardinality of all countable infinite sets is identical.",
"This means there are not \"more\" even numbers than integers. You can match them 1:1 by the relationship n-->2n",
"edit: not all infinities are the same, but the infinities of your examples are the same."
] | [
"Sorry, but the size and cardinality of all countable infinite sets is identical.",
"This means there are not \"more\" even numbers than integers. You can match them 1:1 by the relationship n-->2n",
"edit: not all infinities are the same, but the infinities of your examples are the same."
] |
[
"Why are diesel engines preferred over petrol in heavy towing/moving applications?"
] | [
false
] | null | [
"Diesel is preferred for the following:",
"I'm sure others will chime in soon; I work on airplanes, haha."
] | [
"Here's",
" a Popular Mechanics article on that, the main points seem to be that, 1) diesel engines are intrinsically costlier because of reasons (higher compression ratio, the need for high-pressure pump and after-treatment system to comply with environmental regulations, etc), 2) both diesel and gas in the US a... | [
"Diesels are more efficient when they're bigger; ship engines have cylinders a metre across. Small diesels (for cars) were hard to do well, but Volkswagen's TDI changed that and now they're the leader in diesel cars."
] |
[
"Can babies get vaccine antibodies from mom through her breast milk?"
] | [
false
] | There’s a great body of research on transfer of immunity through the placenta wall, but I’m having difficulty in finding good information on how well antibodies are adopted when absorbed through the gut, whether it be through colostrum or breast milk. Also, considering the change in gut behavior from a closed gut to an... | [
"Yes but I don't believe there are any studies testing thresholds for protection. Probably unethical.",
"For SARS-CoV-2 vaccines there is evidence of transfer through breast milk:",
"",
"This study found robust secretion of SARS-CoV-2 specific IgA and IgG antibodies in breast milk for 6 weeks after vaccinati... | [
"The “open” vs “closed” gut is a myth (",
"https://www.google.com/amp/s/scienceofmom.com/2016/05/03/whats-up-with-the-virgin-gut-do-babies-really-have-an-open-gut-until-6-months-of-age/amp/",
"). So even if they do get antibodies through the breast milk (which seems to be the case in several early papers), ther... | [
"Also, have there been any investigations on antibodies in babies? Babies get bloodwork done at 9 months. Have they tested that blood for antibodies in any cases?"
] |
[
"Why are the centers of galaxies so bright?"
] | [
false
] | Looking at picture, it seems that there's some space between the center of the galaxy and the clumps of matter/stars/gas that form the inner ring. Yet the center is visibly brighter. Is this an effect of the camera/photo, or is the center actually giving off that much light? I was under the impression that many galacti... | [
"If you're interested in this topic, you might also like to read up on ",
"active galactic nuclei.",
" Also ",
"here",
" and ",
"here",
"."
] | [
"Spiral galaxies like the Milky Way and the Andromeda galaxy (M31, in your photo), are believed to have formed around black holes that were produced by some of the earliest, most massive stars in the Universe. Their gravity \"seeded\" the formation of entire galaxies, even though their masses constitute only a tiny... | [
"Spot on response! Thanks!",
"Some spiral galaxies funnel unthinkably vast quantities of matter into their central black hole, and the incredible amount of energy liberated as it falls into the hole often causes it to shine far brighter than all the stars in the host galaxy combined.",
"Is this process sustaina... |
[
"Would it be correct to think that sexual genetic heredity is patriarchal?"
] | [
false
] | Since fathers must pass their Y chromosome to their sons, but mothers can pass either one of their X to their daughters, that means the male hereditary line will always have an unbroken chain of Y's passed down. If a daughter can receive either one of their mother's X's (i.e. they're not enumerated in any way), then th... | [
"Yeah, the y-chromosome is passed down from father to son for the most part unchanged, and the mitochondrial DNA is passed down by the mother mostly unchanged. That's why you can use Y and mtDNA to track genetic ancestry."
] | [
"There aren't very many genes on the human Y chromosome (see ",
"wikipedia",
", so the Y probably doesn't have a huge impact on male phenotypes.",
"There are also some species (birds, some fish and insects) where sex determination is flipped around: males have two copies of the Z chromosome and females have o... | [
"Y probably doesn't have a huge impact on male phenotypes",
"Cool, that's actually what I wanted to know most of all, actually. So yes, it is patriarchal, but it doesn't have much significance to the resulting phenotype.",
"If sex determination is flipped around, then what is used to determine sex? "
] |
[
"How did the genetic diversity of a species increase in the early evolutionary past?"
] | [
false
] | Apparently, in case of a mayor global disaster, say the zombie apocalypse, humanity would become extinct if the number of survivors goes below a certain threshold due to a lack of genetic diversity (inhibiting the ability of a species to create healthy offspring and in and other words; survive in the long term). If tha... | [
"Random mutation.",
"There are several ways this can happen:",
"1) Radiation & chemical mutagens. Strong ionizing radiation can cause breaks in DNA, which are then repaired. Certain chemicals can also introduce mutations by physically damaging the DNA. Sometimes, the repairs aren't quite right and bases are los... | [
"Mutation is a rare cause for evolution. It's usually isolated groups and genetic variability.",
"Where does the genetic variability come from?",
"I'm sorry, but this is totally wrong. You can't have anything to select on unless you have mutation. ",
"Mutation is rare at the per base pair level to be sure. Cu... | [
"Why does everyone always go for the zombie apocalypse?",
"Anyways:",
"assuming that for every organism the population starts out small",
"This is not true. (Also, I'm assuming you meant \"species\" instead of \"organism\". The word organism refers to an individual. \"Species\" refers to the collective group ... |
[
"How will/are human bodies adapt(ing) to increased body fat if obesity continues through many generations?"
] | [
false
] | Is there any evidence of human bodies adapting to obesity? If it is true that you can be genetically obese then are those humans better adapted for this? Would the human body be more likely to adapt to automatically store less fat, or to strengthen its organs/structure to be able to cope more easily with increased body... | [
"If being overweight has enough impact on a person's average reproductive success (i.e. total number of children who survive long enough to reproduce themselves), it's not impossible that we'll eventually see human evolution select for people who are less susceptible, perhaps because they retain less fat, have less... | [
"Obesity ",
" affect fertility, but with our increasing abilities to raise or lower fertility that may not correlate as strongly with reproductive success as it would with other species any more.",
"Sometimes I wish for immortality just so I can see what happens next."
] | [
"Imho we must make a difference between medieval fat/plump and our modern morbidly obese."
] |
[
"Career choices for Env. Scientist versus Chemist or Biologist?"
] | [
false
] | [deleted] | [
"Biologist here. The way you will decide the field you want is based more on the research experience you have rather than the classes you will take. So, don't sweat the specifics of your decision too much at this point. ",
"Take all the classes that are required plus anything that looks interesting, and when ... | [
"I concur with twinklingyoureye. Your research experience will help you decide to a greater degree than the classes. I was originally in a similar position as yourself. I started undergraduate classes thinking I would go into environmental science. After freshman year I started research in a microbiology-type l... | [
"I found out about the microbiology lab through my advisor, and it was not part of the curriculum. The only way you are going to find these opportunities is to ask. Most professors are willing to talk, if you want to go durring office hours or make an appointment, it doesnt really matter. Its what you talk about ... |
[
"We all know about trilobites, dinosaurs, pterodactyls and other animals that have gone extinct, but have we discovered any extinct plants with unique features not seen in plants today?"
] | [
false
] | null | [
"Paleontologists have found many interesting species of plants that no longer exist. Plants have been on land longer than animals have and they have had hundreds of millions of years to evolve. The unique adaptations in extinct plants were used to solve the same problems plants still have (how to reproduce, how t... | [
"Thank you for your clear answer - a bit sad that it's highly unlikely we'll ever now more. Nice example of convergent evolution with the seed ferns though!"
] | [
"Silphium was a plant used by the romans, for several medicinal purposes and according to wikipedia it was used as a contraceptive. It was so used that it became extinct.",
"\nHere is the article ",
"http://en.wikipedia.org/wiki/Silphium",
"I dont know if that helps, but i hope it does"
] |
[
"New job in biology/similar to a very old guy (30) not in science?"
] | [
false
] | null | [
"No problems, trying also field specific subreddits like ",
"r/biology",
" is probably good."
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"A good home for this question is our sister subreddit ",
"/r/AskScienceDiscussion",
". It might be too open-ended or speculative for ",
"/r/askscience",
". ",
"/r/AskScienceDiscussion",
" is... | [
"I’m sorry, didn’t know about the sub. Thanks"
] |
[
"I've seen three huge tree plauges in my lifetime. Have they always been this common?"
] | [
false
] | null | [
"Questions based on discussion, speculation, or opinion are better suited for ",
"r/asksciencediscussion",
"."
] | [
"I was hoping for an evidence based discussion?"
] | [
"Questions based on discussion, speculation, or opinion are better suited for ",
"r/asksciencediscussion",
"."
] |
[
"Light exposure influences our production of melatonin [right?] so does it affect the blind as well?"
] | [
false
] | does it 'affect' the blind any differently? This leads to my Are sleep cycles in general relatively different to the blind? | [
"http://jcem.endojournals.org/content/82/11/3763.full"
] | [
"So basically:",
"These results indicate that a higher proportion of NPL subjects have abnormal melatonin rhythms compared to those with LP. ",
"LP: Light Perception",
"\nNPL: No Light Perceived."
] | [
"Melatonin and melanin are different things. I'm not an expert so forgive me if I use wrong terminology, but melatonin production increases when you are in the dark, and makes you tired, eventually falling asleep. So OP's question was, do you have to see that it is dark, or does your body just know that it is dark?... |
[
"Did the DDT ban cost humanity millions of lives lost to malaria?"
] | [
false
] | [deleted] | [
"No. The use of DDT for malarial control was not banned."
] | [
"It was used for agricultural pest control as well as mosquito control. Its use as a crop spray was banned."
] | [
"It was used for agricultural pest control as well as mosquito control. Its use as a crop spray was banned."
] |
[
"Is this statement regarding GMO Canola oil true? \"As a rule of thumb, if the bacteria that make things go bad won’t eat it, your liver will not be able to digest it either.\""
] | [
false
] | Source: | [
"Well that's just the silliest thing I've read. There are lots of reasons bacteria don't colonize a food, from it being sterilized to it being toxic to them (but not humans) to it being nutrient-poor for bacteria (but not for humans), etc...",
"Garlic takes forever to decompose, too, but no one is saying don't ea... | [
"The statement is misleading. The shelf life of oils are all relatively similar. ",
"Here is a table comparing shelf lives of different oils",
". Canola oil is no different than oils from other sources, so the point being made is kind of ...pointless. "
] | [
"Two things:",
"1 ) No, it's not a good rule of thumb, since most bacterium cannot grow in oil. In fact, placing a layer of oil over things is used as a preservative, since it prevents stuff from landing on it and reduces gas exchange.",
"2 ) Strangely, the given history of Canola oil on the website seems to ou... |
[
"How do deep space probes communicate with Earth?"
] | [
false
] | This one has been boggling me for a long time now. Let's say that a distant probe like Voyager 1 tries to communicate with earth. As per Voyager 1 is roughly 141 Astronomical Units away from earth which translates to roughly 19 light hours. AFAIK Voyager 1 needs to point it's antenna directly to Earth to communicate, s... | [
"Electrical Engineer here but my specialization was in radar specifically fields and waves so a physicist or someone more familiar will likely have more specifics.",
"Short answer: They point a dish as close to pointing directly at Earth (maybe they lead it a bit if transmitting, or trailing if receiving) and kee... | [
"Arctan of 2 million km divided by 141 AU is approximately 0.005 degrees. Main lobe of Voyager antenna pattern must be much wider than that. Not only because it's difficult to form such a narrow beam with a relatively small antenna, but also because it's difficult to aim it so precisely."
] | [
"Superb answer Malforus. I think I was missing the tight schedules and precise calculations part which in hindsight seem kinda obvious for this type of communications. Thanks for the detailed answer :)"
] |
[
"If every cell contains all our DNA, how does the body know to only translate certain genes in certain areas?"
] | [
false
] | For example, why is the gene coding for earwax only translated into a protein in the ear canal. Are genes suppressed in some way when cells are differentiated in development? Or is there some other mechanism at work? | [
"The posters here rightly talk about transcriptional regulation -- taking the DNA code and making it into mRNA. This is enormously complex and depends on lots of things, including DNA structure and folding and other \"epigenetic\" cues as well as signal transduction pathways, which convey signals from the outside e... | [
"I'll try and give a broad but complete answer. This is assuming you have some cell biology background for terminology. ",
"Essentially, every unique cell type (say heart cell vs. cells in the ear canal) has built up a complex network of transcription factors and co-factors interacting with the genes of the cell.... | [
"This.",
"From an oversimplified base point, imagine that the moment a sperm hits the egg, a protein is produced. Diffusion will spread the protein around, but there'll be more in the front than the back, and more at the bottom from gravity's effect. As the cell divides, these concentrations give you forward/back... |
[
"What is the smallest yield possible of a nuke?"
] | [
false
] | null | [
"At least the smallest weaponized nuclear payload was approximately 6 kilotons. The W54 nuclear warhead was equipped to the portable M-388 Davy Crockett nuclear launcher. The warheads would fit into small casings or backpack nukes.",
"If this is the absolute smallest possible, I don't know. This was the smallest ... | [
"The smallest intentional (non-fizzer) nuclear explosions are a few grams TNT equivalent.",
"The term you want is ",
"Hydronuclear",
".",
"When designing a nuclear weapon, you need to form a critical mass (obviously), and you do that by taking a subcritical mass and squeezing it in a conventional bomb.",
... | [
"and it was discontinued because even after firing it at it's max range of 3 miles, the crew would still be in range of radioactive fallout."
] |
[
"What is the margin of error in across the billiards shot list for anything from an easy to difficult shot?"
] | [
false
] | As the title says I want to know the amount of room for human error there is in various shots you would make in a game of pool/billiards. | [
"Speaking as a pool player:",
"For professional players, the margin for most common shots is < .5%. I'm basing this on their ability to run drills, as well as the high run numbers in straight pool (400-500 shots in a row, including difficult break shots), where a good number of those shots are difficult and requi... | [
"I'm not quite sure I understand your question. The game is played completely VIA human control. So depending on what they choose to do, there will be different amount of human error.",
"A complete newbie could completely miss the ball, while say a theoretical perfect player (CPU perhaps?) can calculate the exact... | [
"Ok so lets take a dead on shot straight to The center pocket. 6 inch spacing between pocket and ball and 6 between ball and cueball. How much area is there on the side of the curball to cleanly pocket the ball"
] |
[
"Is it possible that emotions were developed from a consistent response to similar situations?"
] | [
false
] | I would think that emotions didn't always exist throughout life and had to be developed. Would being exposed to the same or similar scenario eventually lead to developing that emotion? Examples: Seeing a potential mate could lead to Love Having food stolen could lead to Anger | [
"In order to answer this question, we need a working definition of 'emotion'. To this end, we can use the definition proposed by Tooby & Cosmides (1990) of ",
". In layman's terms, emotions help us make sense of our environments and circumstances.",
"From the standpoint of evolutionary psychology, it's likely t... | [
"I think you're considering the effect of repeated exposure to emotional stimulus ",
", rather than as a trait cemented into the species as a whole via natural selection. ",
"Yes, in individuals, as they are exposed to repeated stressors they experience diminished emotional responses. This is why the first time... | [
"While this makes sense on the surface in a Pavlovian way, I would like to ask how this works with desensitization over time to the same emotional stimulus. ",
"Wouldn't repeated encounters with stressors lead to less and less emotional response over time rather than cementing it into the evolutionary psyche?"
] |
[
"If we can let √(-1) equal to \"i\" to do more more complex mathematics, why cant we do the same for (1/0).?"
] | [
false
] | null | [
"There are fields in math where division by zero is okay. But you have to be careful of the context. If you think of division as an algebraic manipulation on numbers, then it doesn't make sense and you easily end up with contradictions like 1=0. However you can view things in a geometric way and get neat results.",... | [
"My favorite explanation of the Riemann sphere :",
"\"Riemann sphere, which is where we take a space shuttle and use it to fly over and drop a cow on top of a biodome, and then have the cow indiscriminately fire laser beams at the grass inside and around the biodome. That's my intuitive understanding of it anyway... | [
"The way that we have defined zero, it doesn't make sense to.",
"Zero is a special number. It's such that zero added to anything has no effect, and multiplied by anything equals zero. This second definition is where we run into problems. Suppose we have x and y, where x=/=y. Then observe that x * 0 = y * 0 = 1 * ... |
[
"What evidence do we have that asymptomatic spread is significant with COVID?"
] | [
false
] | This is an honest question. Most searching I've done seems to indicate that we don't have much evidence. Articles citing evidence tend to just link to articles making claims, and the few studies I've found cite computer models, which I don't take as evidence. Evidence would consist of measuring the frequency with which... | [
"The main issue isn't finding evidence of transmission from people with no symptoms, it's distinguishing presymptomatic from asymptomatic cases, and to some extent, distinguishing ",
" symptoms from ",
" symptoms -- it's a gradient of severity, not an on-off switch. But to an extent, that becomes irrelevant; if... | [
"There are countless viruses out there which cause no noticeable symptoms. I'll be bold enough to say there are probably more viruses out there that cause no symptoms than ones which do - we just don't bother studying them (or are even aware there is something to study - it's difficult enough to find a virus you kn... | [
"Thank you, that makes sense.",
"This virus is showing me how little I knew about viruses."
] |
[
"How would every nuke in existence detonated at the exact same place differ from just one?"
] | [
false
] | null | [
"This is fairly difficult to answer in very specific terms; the experiment has probably never even been simulated (even down in the deep dark heart of DOE classified computing).",
"But, in general, I think that we can draw some insight from the test sites out in the pacific (e.g. Bikini Atoll) where many nuclear ... | [
"While I love your answer, I'm wondering where you got the last calculation from, and also why the analogy is helpful...have we experienced such a thing, or is it common to relate large explosions to iron meteors?"
] | [
"True, I was just trying to avoid the phrase 'nuclear energy,' and I forgot we physicists tend to use terms like 'chemical energy' more loosely than they do in high school chemistry. "
] |
[
"Why does low frequency radar have poor resolution/accuracy when used to detect and track objects?"
] | [
false
] | [deleted] | [
"It is a fundamental property of waves. Waves with longer wavelengths simply can't carry as much information. More formally, the amount of information that a wave can carry is measured by its bandwidth. In simplified terms, a sine wave can carry information by tweaking its shape slightly. Mathematically, tweaking t... | [
"You seem to be confusing pulse width (which is related to bandwidth) with wavelength. A single-wavelength wave containing no other wavelength components carries the same amount of information no matter what the wavelength is. The only information it carries is: intensity, polarization, and wavelength. In contrast,... | [
"Long wavelengths travel farther. Also they can see \"through\" small objects like leaves. "
] |
[
"Why don't I receive a cell phone signal when I'm on a plane?"
] | [
false
] | null | [
"Cell towers generally have a relatively low power signal (a few miles to tens of miles of range), and are meant to cover a specific area. When you get close to the border of a cell you are handed off to the next cell.",
"You would not be likely to receive a cell signal in a plane at 35,000 feet for a couple of r... | [
"The FAA ban lift will presumably allow the installation of cellular infrastructure onboard aircraft providing service to mobile devices onboard. This would rely on satellite backhaul or dedicated air to ground communication, not terrestrial cellular networks.",
"This is different than the recent lifting of the b... | [
"The FAA ban lift will presumably allow the installation of cellular infrastructure onboard aircraft providing service to mobile devices onboard. This would rely on satellite backhaul or dedicated air to ground communication, not terrestrial cellular networks.",
"This is different than the recent lifting of the b... |
[
"How did the first scientists discover that radiation was bad for you?"
] | [
false
] | Trying to understand exactly when we realized that certain elements, and or reactions were reactive, and that the results from those reactions were deadly. Did the early scientists pioneering this field just die as a result of discovering it? Or were they correctly able to theorize what elements would do and protect th... | [
"HJ Muller discovered that X rays cause mutations by giving fruit flies varying doses of radiation. However, Roentgen, discover of X rays, knew that x rays caused burns in high enough doses (although he didn't realize the cause)."
] | [
"Weren't suspicions raised by early scientists who developed diseases as a result of working with radioactive materials?"
] | [
"For a while, radioactivity was considered a cure-all.",
"Then people started getting sick."
] |
[
"Is it possible to detect an exoplanet by measuring the change in polarization of starlight as a iron-core planet transits in front of it?"
] | [
false
] | [deleted] | [
"In order for magnetic fields to affect light, the light must be traveling through (and not be completely absorbed or reflected by) a medium. At most, this implies that if the magnetic field is strong enough, light passing through the ",
" of the planet and then making its way to detectors on Earth could, potenti... | [
"Since most planets rotate roughly on the same plane as their orbit, most polarization signatures would be significant."
] | [
"I'm not understanding the part where polarization can only occur in a medium. Is there a source for that, that you're aware of.",
"Also, I wonder if that would therefor be useful in detecting planets with rings."
] |
[
"Is it possible for cavitation bubbles to be formed in gases?"
] | [
false
] | [deleted] | [
"Cavitation is specifically a phenomenon where the pressure in a liquid drops so low that it reaches the vapor pressure of the liquid and therefore induces the formation of a pocket of gas. There is no analogous phase transition for gases."
] | [
"Not specifically cavitation, but an analogous process would be flow separation in gases. When this happens, the pressure in the separated region drops significantly, ",
"almost to the point of a full vacuum which causes moisture in the air to condense out.",
" ",
"Supersonic flow causes a similar but more ... | [
"Yes. ",
"Form (parasitic) drag",
" increases with speed and creates a ",
" low pressure region behind objects moving through a fluid. "
] |
[
"Question from my 8 year old daughter: Can scientists invent something that isn't made up of atoms?"
] | [
false
] | I had absolutely no idea - can you give me an answer beyond yes or no? Her teacher told her that everything was made of atoms and we were talking about what atoms were made of, but I didn't have a good answer for this. EDIT: Thanks everyone - we googled quark gluon plasma last night and thanks to the term "squishy fi... | [
"Well, a quark gluon plasma is made of quarks and gluons but is too energetic for atoms to exist."
] | [
"You can't make anything out of it. Basically it's a really short lived spark of squishy fire."
] | [
"that, my friend, is up for debate"
] |
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