title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why does the interaction between two magnetic fields creates force?"
] | [
false
] | like the force between two magnets | [
"Do magnets work this same way? I understand the intrinsic magnetic moments of the atoms that align and create a magnetic field, but how do they interact with other magnetic fields?",
"Edit: I'm sorry if im not being very clear"
] | [
"I think I understand you clearly. The answer is that the electron magnetic moment also feels a force due to an external magnetic field. In a permanent magnet, where the moments all align, the whole magnet has a net magnetic moment, and this moment feels the force. It might help to consider the magnetic moments as ... | [
"The Wiki article on the ",
"force between magnets",
" covers the basics and can lead you to more advanced topics. I mostly think about the problem in terms of ",
"magnetic dipoles",
".",
"If you know some physics/vector calc, I could direct you to lecture notes: ",
"http://farside.ph.utexas.edu/teachin... |
[
"Are there any inherent issues with using tank tracks at high speeds?"
] | [
false
] | Are tracks inherently limited to relatively slow speeds due to mechanical issues or is it more because the vehicles themselves are heavy? Even the fastest tracked vehicles such as the M18 Hellcat, the BT-7 or the FV 107 Scimitar weigh multiple tons due to armor, armament and other equipment. The question is, would it be feasible to create a "tracked sports car" with a lightweight chassis, a powerful engine and not much else to weigh it down or would issues with the tracks themselves (friction? wear?) effectively limit its speed? | [
"Googling a bit, I noticed the ",
"Ripsaw",
" unmanned light tank---apparently the prototype can do 0-65 mph in 3 seconds, and and according to ",
"this article",
"The original speed goal for Ripsaw was approx. 80mph, but the Howe brothers have discovered that driving UGVs remotely can get scary and precari... | [
"I think this question assumes a cause and effect relationship between using tracks and going slow in a massive vehicle. There is a relationship between them, but I think it goes the opposite direction that you seem to think.",
"The reason to use tracks instead of tires is to spread the force from the weight of a... | [
"Last part should be F=ma to accelerate the tank or apply a force to overcome resistance would be a lot more than the road could take. E=MC",
" only come into play if the tank approaches light speed."
] |
[
"Killing germs..."
] | [
false
] | I don't have much info on this topic but I would like to know what happens after a germ is dead? Does it have a body and if not what is it? Lastly if it does then what happens to the body? | [
"To add to what's already been said, the act of killing pathogens in your body can result in more disease. One example is the ",
"Jarisch-Herxheimer",
" reaction, in which the rapid lysis of spirochete bacteria results in toxin release and subsequent fever/chills/myalgias from inflammatory cytokines."
] | [
"Yes, it has a body. If the bacteria are killed inside an organism (like a human, for example), they will be eaten by some specific immune cells and decomposed by some enzymes that they synthesize. This is called phagocytosis. If the germ is killed outside the body, by using alcohol, for example, it will also break... | [
"There's a body, kind of, generally, like a popped balloon. The membrane of the bug will probably hang around a while, as will the cell wall. The internal components will generally leak out into the environment as the membrane and wall break down. Most of the \"stuff\" will either get dispersed, react with other th... |
[
"Are dolphins afraid of death? Or, are other species aware of their own mortality?"
] | [
false
] | null | [
"The short answer is that we're really not sure. Some researchers say that evidence suggests that some species do, while others claim that we are just anthropomorphizing them. The two big problems associated with this question are 1) death is not observed in the wild very often, so it's hard to gain a lot of reliab... | [
"I'd like to extend this with a question as well. If they aren't, why do they feel fear when something attacks them?"
] | [
"We can't really know what another creature thinks, feels, or understands, until we can communicate effectively with that creature. We can guess, and anthropomorphize, but there is no way to know. Luckily, we have finally gotten off our high horse enough to realize other species might be worth communicating with. W... |
[
"I have a question about double-blind experiments"
] | [
false
] | So the way I understand it, the purpose of a double-blind experiment is to prevent the experimenter from hinting at the "right" answer to the subject. How can he hint at information he doesn't know? But then I thought, well, that almost makes the experimenter his own "subject"; he has to get the vials from someone. Would that someone not be able to telegraph information just as easily? If the only one who "knew" which was which was a computer, that would certainly alleviate my concern, but in cases where that's not possible, do my concerns even have merit, or am I missing something? Is there a certain amount of information hiding that's just considered "good enough," even if it's not perfect? | [
"The whole point about double-blind experiments is exactly that - the experimenter cannot \"hint at information he doesn't know\".",
"Now it's possible that when the researcher gives two bar-coded drugs to the experimenter, he'll say \"be careful with the one on the left, it's expensive!\" But normally that's not... | [
"he has to get the vials from someone. ",
"He doesn't have to interact with that person, though. They could just label and package the vials, and leave them on the experimenter's desk."
] | [
"Check out the ",
"wikipedia article",
" for some more info on this."
] |
[
"Is the fabric of space-time fixed or fluid?"
] | [
false
] | As far as I can tell there seem to be three competing theories as to the microscopic structure of the fabric of space-time: lumpy (quantum packets of energy), silky (strings) or foam (quantum foam). Some (e.g. Einstein) argue that there is no such thing as a "fabric" at all, even though this is always the preferred visualisation (e.g. space-time expanding from the Big Bang, ripping in the Big Rip, planets curving the sheet of space-time etc.) Now, do particles with mass (e.g. me) move THROUGH (swimming in a pool), or ON the hypothetical fabric (a projector image on a wall)? E.g. I recall string theory saying that a particle is just a specific vibration of a string. When the particle moves, is the string moving with it, or is the vibration passed to the next string? (I guess this basically comes from the "flatland" visualisation, where I always took Mr. Flat to be moving on the stationary background fabric.) | [
"The fabric is just an analogy. There's no actual fabric."
] | [
"Ok, so that means I take my strings with me wherever I go?"
] | [
"As ",
" notes, it's not really a fabric. The way we actually describe spacetime is by noting the distance between two neighbouring points in a particular region (this is called the metric, and can be considered to be a function of two points in spacetime).",
"You might expect the distance between two equally s... |
[
"Do your nerves send a message to your muscles directly when you experience pain?"
] | [
false
] | I attempted to look this up but wasn't having a very lucky Google day. I remember reading that when your nerves "sense pain", it's almost as if they bypass your brain completely and will send a message like "MOVE YOUR HAND OFF THE HOT PAN" directly to the muscles. It makes sense because when you experience pain it's as if your body reacts automatically. Is there validity to this? | [
"Yeah, it's a reflex arc. Pain is sensed by your peripheral nerves, these sensory nerves then synapse in your spinal cord onto motor neurons, which in turn go back to the muscles and contract them to draw them away."
] | [
"This is exactly it. You have some neurons that go directly to your spinal cord (or in some cases, skips the spinal cord entirely), synapse (connect) on another neuron (called an interneuron) which then a) sends a signal to the brain letting it know something's going on and more importantly b) sends a signal (via ... | [
"Thanks for the input."
] |
[
"They say that to test String Theory, we need to build a particle accelerator as large as out galaxy. Is it a technical limitation or a fundamental one?"
] | [
false
] | [deleted] | [
"It's a little of both. With how we currently probe high energy regimes, there is a fundamental limit to the energies we can obtain from collisions, related to accelerator designs (including size). But it is, pedantically, a technological limitation, because the science doesn't say \"the only way to test string the... | [
"There's wakefield accelerators, which are smaller and way more efficient. They work by using a laser pulse to create very strong electrical fields in plasma. Electrons then ",
"surf this wake",
" to very close to the speed of light.",
"That can't test string theory, but a GeV particle accelerator that fits i... | [
"\"if you want to avoid building a very large accelerator, you need a breakthrough in how you probe very high energy regimes.\"",
"Are there any breakthroughs being made in that regard?"
] |
[
"If a woman's on birth control that stops her menstruating once a month, will she remain fertile for longer?"
] | [
false
] | My girlfriend is on a birth control regime where she only menstruates once every three months. From what little I understand of fertility in women, you've got pretty much a set number of ova and once you run out, you hit menopause and can't conceive. Since she only has 4 periods a year instead of 12, does that mean she'll hit menopause later? | [
"That makes sense biologically (and is why nulliparity is thought to contribute to earlier menopause). However, this is not always supported by epidemiological studies. ",
"This study",
" found that history of oral contraceptive use significantly ",
" the risk for ",
" menopause (defined here as prior to ... | [
"So essentially the answer is \"No, but we're not sure why\"? "
] | [
"This isn't true, contraceptives can prevent menstration as well. They essentially trick the body into hormonally thinking it's already ovulated, and perhaps even implanted, so it won't shed the lining of the uterus until the dosage is stopped or changed. Hence why the most common OC schedules include a week of p... |
[
"Is it known when/where Rh negative people first appeared, or have they always been around?"
] | [
false
] | I stumbled upon a clickbaity article claiming that 'Rh negative people are aliens' and a bunch of other nonsense, so I started looking around and it turns out there isn't much info online about the 'genealogical history' (probably not the right technical term for it) of Rh negative people. A quick look at the Wikipedia page for tells me it's mostly European lineages that are Rh negative, so intuitively I would think that a mutation occurred in Europe at some point, but this is really just a guess. Is there currently any consensus about this? | [
"There are theories out there that Rh negative individuals have overactive immune systems which help to protect them against some viruses. An evolutionary advancement maybe? But on the other hand, that same overactive immune system can lead to autoimmune disorders. You can't win for losing."
] | [
"Do you have any peer reviewed sources for this? "
] | [
"Can you prove it?"
] |
[
"Even though we see different structures at different spatial scales of astronomical observation, why do many of us believe cosmological models which inherently assume homogeneity and isotropy?"
] | [
false
] | Been a while since I read about FLRW cosmology, but this question bothered me then. Am I wrong and people don't believe these models anymore? I know background radiation has the properties mentioned in the question, but aren't cosmological models supposed to be global descriptions? Clarification would be great thanks! | [
"Because we do see homogeneity and isotropy on the largest scales, larger than about 100 Mpc.",
"The simplest example is the cosmic microwave background. It looks like ",
"this",
". It's full of structures, spots that are hotter or colder than the average. But they're only hotter or colder by about a part in ... | [
"Beyond a particular scale (known as the end of greatness, about 300 million lightyears), large scale structures from smaller scales are effectively homogenized and isotropized. ",
"Basically the term \"large scale\" is very relative in this context. The structure is large scale when compared to our own galaxy, b... | [
"This",
" is a helpful graph. Even before the CMB we can see the strength of structures starting to flatten out at large sizes."
] |
[
"If I'm moving in a circle or an ellipse, am I changing direction? If so, am I expending energy?"
] | [
false
] | null | [
"Yes, it’s changing direction, but its energy is not necessarily changing."
] | [
"But how is it possible to change direction without expending energy? Doesn't that involve doing work?"
] | [
"Nope. Changing direction without changing speed doesn't change the energy of the object (assuming there's no direction-dependent potential energy).",
"As for work, the infinitesimal work done in some infinitesimal amount of time is equal to the dot product of the force and the displacement. For an object moving ... |
[
"How has the magnetic reversal of poles affected the evolution of life?"
] | [
false
] | This has been asked by someone else, but the answers were rather unsubstantial and not particularly well-sourced. Anyways, during physics class today we discussed how the the magnetic poles reverse and how it occurs every 700k years. We also discussed how during such a reversal, the radioactivity going through atmosphere would increase. In addition to this, we also discussed how certain animals use magnetism to know where to migrate to. So my question is this: wouldn't this reversal increase the mutation rate of evolution (due to the change in the atmosphere) and wouldn't it disrupt many migrating animals? And, if so, what kind of affect has this or hasn't this had on the evolution of current animal life? | [
"There is certainly speculation about what happens to the biosphere during magnetic reversals, where the Earth's magnetic field can drop to about 10% it's current strength. The increased impact of energetic particles on the biosphere during reversals is considered negligible by most, as the main shield against harm... | [
"There has been speculation that species origination rates would increase during reversals; but the record isn't really good enough to prove disprove it. In theory, more ionizing radiation coming through the atmosphere will increase the rate of mutation.",
"Basically, the increased proposed rate of extinction may... | [
"the magnetosphere handles extra bursts of radiation, like in solar flares and wind. but common constant radiation bombardment is handled by the atmosphere, like you said."
] |
[
"How can solid or gaseous elements by themselves become electron donors? Can shining light on the element or any other feasible process actually work? Can we bypass the electron affinity energy requirement and have the electrons donated?"
] | [
false
] | [deleted] | [
"produce electrons",
"It's not quite accurate, the electrons are excited by light and released from the atoms.",
"But yes, depending on the definition of \"light.\" X-ray photons will certainly release electrons from many things including noble gases. See: ",
"https://en.wikipedia.org/wiki/X-ray_photoelectron... | [
"Absolutely, there ",
" ways to calculate how much (actually, which wavelength) of light is needed to ionize (eject) an electron from a given element/molecule. Experiments exist too, like the above mentioned X-ray photoelectron spectroscopy (XPS).",
"Edit: The wavelength of the incident light decides if you'r... | [
"Thank you! So there could also possibly be a way to calculate how much radiation and light would be needed, in order to eject electrons from let's say, oxygen, correct? So we could still apply this to a non-metal in order to be properly aligned with the photoelectric effect."
] |
[
"Why does biology \"not make sense\" without evolution?"
] | [
false
] | I've often read this in articles about why evolution is true, but no one really explains why this is so. How does biology as a whole fall apart without evolution? | [
"I'm not sure how to properly answer this as I'm not really sure what you do or don't know so I'll go as simply as possible.",
"I think what the statement means, in it's current usage, is a lot of the things we understand about animals, plants, etc make sense when viewed through the framework of evolution. For in... | [
"Because there is a metric ton of whack \"design\" in biology, like the fact the the eye in vertebrates has a blind spot because the vein passes through the retina rather than being attached behind it. This is, we know now, a result of the repurposing of an earlier structure rather than an intentional design featur... | [
"We aren't very certain about gravity, or how or why it it exists. we just know we can measure it and know how it effects some things.",
"You've just described ",
". There's nothing about gravity that's more mysterious than any other phenomenon."
] |
[
"How big would LaGrange Point L4 (or L5) be... Are we talking 100s of metres or miles?"
] | [
false
] | I've read that they are like a gravity bowl, catching dust and trojan asteroids. Just wondered how 'big' would this bowl be? Seems like an ideal place(s) to build a massive space station. | [
"The Lagrange point itself is just that - a point, of zero size, but the L4 and L5 points are special in that there can be stable orbits around them. The points are ‘hilltops’ of maximum gravitational potential, which does not sound stable, but due to the orbital dynamics, when it starts so ‘slide’ off the hilltop ... | [
"How large can the orbit be? "
] | [
"I don’t know any hard numbers, but very large. For example in this ( ",
"https://commons.m.wikimedia.org/wiki/File:InnerSolarSystem-en.png",
" ) image of the asteroids orbiting Jupiter’s L4 and L5 points (they are the green ones) it is apparent that they are very widespread, so it seems that as long as there i... |
[
"I read that when the light of Betelgeuse’s anticipated supernovic explosion reaches earth, it will create two weeks of perpetual daylight. Is this true, and if so, will that have any lasting effect on fauna?"
] | [
false
] | [deleted] | [
"it will create two weeks of perpetual daylight",
"That's definitely a huge overstatement.",
"Betelgeuse currently has an apparent magnitude of about 0.5 (though it's somewhat variable), and an absolute magnitude of about -6 (how bright it would be if it were 32.6 light-years away). Betelgeuse will likely becom... | [
"The Sun passes approximately 16° north of Betelgeuse around the end of every June. If Betelgeuse goes SN in June, we won't get to see much at all. Even at magnitude -10, that's just too close to the Sun. ",
"If it occurs at any other time of our year, it will be visible as a modest white dot in the blue sky ... | [
"Betelgeuses arc in the sky is roughly the same as the sun. So yes, if were it in line with sun at the time of its explosion then you would mainly see, at best, just a dot in daylight. Ideally it will arrange to explode when it's at the complete opposite."
] |
[
"Electromagnetic induction - Alevel stuff."
] | [
false
] | null | [
"Just being more precise: The aluminum ring originally experienced no magnetic field. The magnetic flux was zero. When the AC supply is turned on a magnetic field is created. Now you said yourself that a change in flux causes an induced emf. Lenz's law informs us that this induced emf causes a current whose magneti... | [
"The electromagnet is hooked up to an AC supply: that causes the field it generates to alternate (since the direction of the current alternates). That in turn creates a change in flux through the aluminum ring, which causes the levitation."
] | [
"It's because the B field was initially 0. So, the flux, B*A = 0. When you apply the AC current through the wire loop you generate a B field so the flux is B*A (where A is the area inside the aluminum coil). Hence change in flux. ",
"The reason why the current is AC is because if it were DC then the induced curre... |
[
"When I mow my lawn, am I damaging insect life? How badly am I messing with an ant colony?"
] | [
false
] | null | [
"This is closely related to the topic of my MS thesis actually. The research I did (in hay, not lawns, but still) suggested that mortality due to the mower itself is actually pretty low. On the order of maybe 10%? Most of the changes caused by mowing are due to habitat loss. If there's other unmown vegetation nearb... | [
"You are most definitely killing thousands of bugs. In a square foot of grass there are hundreds, if not thousands of bugs. You probably don't slice very many, but you are sucking them up and crushing them in your bag. If you mulch, you probably kill a lot less, just suck them up and shoot them out. You probably wo... | [
"I'm talking about mostly tiny gnats, spiders, mites, ants, and other tiny bugs that live in the grass. ",
"Aren't these animals small enough to survive a trip through a lawn mower? I've vacuumed up and released spiders before that survived, surely something as small as a mite can make it?"
] |
[
"Could sound waves be used as an insect deterrent?"
] | [
false
] | From my basic understanding of physics, sound waves should effect the flight of small insects. Does this happen to a large extent? Could, for example, mosquitoes be prevented from flying by either a very strong sound signal or one at a specific frequency? | [
"It wouldn't knock them out of the sky, but there are insects that can \"hear\" at ranges above humans, and there are devices that can screw with their heads and confuse/scare certain insects away by playing very high frequencies (sort of like a dog whistle).",
"You have to remember that a flying insect also has ... | [
"there are insects that can \"hear\" at ranges above humans, and there are devices that can screw with their heads and confuse/scare certain insects away by playing very high frequencies (sort of like a dog whistle)",
"There are a lot of devices on the market which claim to work on this principle. However, a 2010... | [
"I am not sure about insects, but mosquito larvae can be killed with sound waves."
] |
[
"Does aluminum-coated roofing insulation work better than matte insulation?"
] | [
false
] | I have recently been exposed to a lot of information about building materials. One debate which came up more than once deals with roofing insulation. Some of the water vapor barriers used under drywall in Poland have a reflective aluminum coating. The marketing materials as well as some people in the construction industry say that this causes it to insulate better. Barring the added thickness of the aluminum, would a reflective coating make the material a better insulator? Please keep in mind that drywall gets attached directly to this, so there is no radiation heat that I can think of which could be reflected. Can someone set this debate straight? | [
"As you imply, a reflective foil coating will only make a difference with regards to radiant heat. As such, foil coated insulation can make a minor difference with regards to insulation placed inside attic spaces -- the type you place on the floor of an attic, or on the floor and walls of attic crawlspaces. ",
... | [
"Note that the \"proper\" place for a vapour barrier depends on the climate.",
"In cold climates, you are correct. In hot, humid climates, you want the vapour barrier between the insulation and the outside world, to prevent warm humid air from outside condensing inside the wall as it encroaches into a cooler, ai... | [
"I did some research with regards to radiant barriers as an undergrad, and one thing that a lot of people might not realize is that while you reduce heat gains from the sun in the summer, you actually increase heating requirements in the winter. In the north, you can actually raise your annual utility bill by insta... |
[
"Will the JWST sun sheild unintentionally act as a solar sail?"
] | [
false
] | I have heard of the concept of solar sails before and am curios (tried searching the subject) if the JWST sun sheild will unintentionally act as a solar sail and need to some how be accounted for and off set. | [
"Yes it will. They even have a small flap on one end of the spacecraft, which is there to help offset the small acceleration from the sun shield.",
"That flap is actually the latest thing JWST deployed earlier today.",
"https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html"
] | [
"The flap probably adds to the the sail effect - but keeps it balanced (no spinning). The force is like a few grams, but that can add up over time. They counteract by keeping the thing on the “downside” (back to earth) gravitational slope of the L2 point, and occasionally boost up a little closer.",
"EDIT - Bette... | [
"Well, most of the force will not add up over time. They're just trying to compensate for the part that would add up.",
"If you just have a flat sunshield orbiting the sun and rotating just enough to always be perpendicular to the sun, then the force would not add up over time and shift the orbit. But it's not pe... |
[
"Is it possible for a deaf person to have tinnitus? If so, how does it work?"
] | [
false
] | null | [
"I am an MD and I have had tinnitus for several years. It is correct, that tinnitus i more a phenomenon of the brain than of the ear (it has been shown, that the \"sounds\" of tinnitus, typically ringing, does not at all behave like sound perceived by the ear). I consider tinnitus an inapropriate cerebral processin... | [
"I am an MD and I have had tinnitus for several years. It is correct, that tinnitus i more a phenomenon of the brain than of the ear (it has been shown, that the \"sounds\" of tinnitus, typically ringing, does not at all behave like sound perceived by the ear). I consider tinnitus an inapropriate cerebral processin... | [
"Some earlier attempts at curing tinnitus involved severing the auditory nerve completely, essentially causing the person to go deaf if they weren't already, and this only cured tinnitus about half the time.",
"So yes, not only is it possible for deaf people to have tinnitus, it is possible for someone with tinni... |
[
"Is there an increasing occurrence of significant earthquakes or just an illusion of such caused by the information age?"
] | [
false
] | null | [
"Major earthquakes have remained constant in number, while (edit for clarity:) ",
" of minor earthquakes have increased in number over the years",
". The increase in minor earthquakes can be explained at least in part by increased monitoring and communication."
] | [
"Right, I should have been more clear: the number of ",
" minor earthquakes has increased.",
"I don't think a proper study has been done on this, which is why the USGS doesn't state that it's definitely an artifact of better monitoring. It could be there are natural cycles of smaller earthquakes, or that they a... | [
"Can you give us some unbiased sources on this?"
] |
[
"What is exactly happening during a panic attack?"
] | [
false
] | I've had panic attacks on-and-off for several years and have yet to fully understand the biological happenings inside my body during an attack other than I feel like I want to run off a bridge with dynamite strapped to my body. I've had people tell me it's a glitch in the fight-or-flight response, that my brain is unable to process the stress being placed on it, my body is dumping it's supply of adrenaline, and a dozen other explanations. Can someone explain biologically what the hell is going on during a panic attack? | [
"NIH to the rescue",
"The \"fight or flight\" response is essentially right. When you experience intense fear stemming from a panic trigger, your sympathetic nervous system goes into overdrive. If you were a human in the wild and a lion started chasing you, the same or similar symptoms would occur: increased hear... | [
"A lot of people think that panic attacks need to have a reason or some type of high stress situation so they make sense. For example, I have a panic attack before a flight because I fear flying. ",
"This is not true for all panic attacks. Sometimes it is a simple change in your bodily sensations that triggers a ... | [
"As an anxiety sufferer, I can confirm the \"very aware\" part. My anxiety increases when I wear a button-up shirt because I can feel the weight of the buttons on my chest. It also increases your awareness of eye floaters, which most people have and don't pay attention to. When I sit motionless, I can feel both ... |
[
"Why does a higher thermal conductivity in the core lead to later inner-core formation?"
] | [
false
] | I am confused--intuitively, it feels like higher conductivity would cool the core faster, and so we'd get an inner core. But in the literature a higher conductivity is always given as a reason for a core (it's never really explained). Can anyone explain what's actually going on? What am I missing here? Thanks! | [
"Higher thermal conductivity --> less vigorous thermal convection --> slower core cooling --> later inner core nucleation",
"Cooling of Earth's molten core prior to inner core nucleation is thought to have been dominated by thermal convection. (In the present era with a growing inner core, compositional convectio... | [
"Thank you for that detailed response. I was suspecting that high conductive efficiency would still be less efficient that convection. Convection cooling the core faster, despite the core having lower thermal conductivity, does make sense."
] | [
"Higher conductivity gets the heat to the core-mantle boundary where it can drive convection in the mantle, and therefore delivery of new materials to the c-m boundary and thence to the core. Keep the heat in the core and all you get is a hot core and cooler mantle with less convection and lower temps resulting in ... |
[
"Do you think there are too many laws restricting scientific research? Or not enough laws pushing research?"
] | [
false
] | [deleted] | [
"Others believe that scientific knowledge is growing too quickly and should be slowed by more laws restricting scientific research.",
"Perhaps one could think that in the 1940s, but now that we've gone 60 years without nuclear war breaking out I think we're in the clear.",
"It's not that the laws are in the way... | [
"It's not so much the laws restricting scientific research for the most part (things like stem cell research being the exception), but rather the lack of sufficient funding. Nowadays, only a small percentage of grant applications will get funded, and basic science research even less so.",
"While there are lots of... | [
"In response to argonaute's and iorgfeflkd's comment on funding limitations on basic science reserach: I completely agree, especially now a days with large corporations no longer pursuing in-house research for the sake of research (e.g., Bell Labs, Kodak, IBM, 3M, Westinghouse, etc.). It's all become, \"when will t... |
[
"What is the cause of the artifactual lines commonly seen on doppler radar images?"
] | [
false
] | What causes this and can we infer anything about weather from them? | [
"Not an expert in doppler radar but I deal with a lot of imaging artifacts.",
"This page",
" lists some interesting Doppler radar artifacts. If the spikes are pointed directly towards the radar receiver, it is almost certainly an artifact. ",
"This paper",
" deals with a \"clutter spike rejection algorith... | [
"Those spikes are actually just post processing artifacts in the display, they don't actually represent any radar phenomenology. "
] | [
"There are a large number of different types of clutter/false returns in radar images. The ones you linked to look like foreign transmitters."
] |
[
"What are the neurological or psychological differences between the auditory hallucinations of voices, e.g., as in schizophrenia, and a persistent negative internal monologue in one's own inner voice?"
] | [
false
] | [deleted] | [
"Schizophrenia by definition means that the person doesn’t differentiate reality. When a person is not schizophrenic, s/he knows that the internal voices are part of their own thoughts; a schizophrenic person doesn’t know what’s real and what isn’t. "
] | [
"Mostly yes in that they are both internally generated. I worked with adults with schizophrenia for 6 years, but they were medicated. Still they couldn’t control the voices and they crowded out their other thoughts. The voices often gave commands or made paranoid statements and made it very difficult for people to... | [
"Do all internal monologues, regardless of their interpretation, classify as hallucinations?",
"Hallucinations",
" are perceived to be external. In that sense, they differ from ",
" monologues which are not perceived to be external.",
"Are the voices their own, or are they foreign?",
"What do you mean by ... |
[
"In the 19th century, the concept of ether was disproven, but the Higgs field sounds a lot like ether to me. How are they different?"
] | [
false
] | null | [
"The main feature of the ether is that it created a universal reference frame as the medium in which light traveled. In order for it to work it had to be possible to tell how fast you were moving with respect to the ether, for example by comparing the speed of light rays traveling in different directions with respe... | [
"The reference frame explanation made it clearer for me. Thank you."
] | [
"Field has a value for each point in space and time. Easier example than Higgs field is the electromagnetic field "
] |
[
"Why are large primes often published in the format of a*2^n +/- 1, such as 3756801695685 · (2^666669) ± 1?"
] | [
false
] | Is this a more clear notation to put these numbers in because it reveals something about the filter applied to the natural numbers to find primes? Why is it that prime numbers tend to be right next to numbers which can be divided by two so many times? | [
"The reason why a lot of the large primes are of the form a*2",
" - 1 is because there is a really fast ",
"test",
" to determine if that sort of number is prime or not. There is also a really fast ",
"test",
" for the primality of primes of the form 2",
" - 1 which are called ",
"Mersenne Primes",
... | [
"This answers why there is at least one factor of two in the questions, but not why, as in the above example, the number which the prime is next to can be divided by two 666669 times. If you break down the number into its factors, and exponents of those factors, then the exponent over 2 is so much greater than the ... | [
"This is the answer I was looking for, thanks!"
] |
[
"What kind of bug is this?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/whatsthisbug",
"If you disagree with this decision, please send a message to the moderators."
] | [
"sorry about that, thanks for the suggestion!"
] | [
"No problem! Good luck."
] |
[
"What exactly causes myocardial hypertrophy?"
] | [
false
] | For instance, hypertension can result in left ventricular wall hyperthropyz but what mediators are exactly in play here? | [
"The largest mediator at play is repeated damage to the heart tissue, leading to scarring and enlargement of the walls. High blood pressure produces increased vascular stress in the heart, causing inflammation and damage. Unlike skeletal muscle, the heart never stops to rest and heal, so the damage is more likely t... | [
"I don't think that there will be a common mechanism as there are different types of hypertrophy. ",
" (thickened wall) occurs due to chronic pressure overload of the ventricle, for instance in the case of chronic hypertension. From Laplace's Law, wall tension is reduced with increasing wall thickness.",
" (big... | [
"Tachycardia is caused by activation of beta adrenergic receptors in the myocardium. Prolonged activation of these receptors leads to predominantly an eccentric hypertrophy, now known as dilated cardiomyopathy. ",
"In clinical settings, chronic cocaine or methamphetamine use will cause this. ",
"So, yes it caus... |
[
"Solar Flares, should I be worried?"
] | [
false
] | null | [
"It's mainly just hyped up, however, a solar flare can indeed knock out a power grid, but only extremely rarely, and usually just by tripping circuit breakers. In March 1989, one of the most powerful storms in modern days occured. It knocked out Quebec's power grid for ",
"9 hours",
".",
"If, for some reaso... | [
"Solid answer, but could you point us to some sources for the amount of damage solar flares could cause and how easily reparable the damage would be?"
] | [
"A solid reply. I'd just like to add that ",
"Coronal Mass Ejections",
" (CMEs) are more often responsible for disruption of electronics on Earth, not solar flares.",
"SDO, one of NASA's solar observatories, caught a beautiful shot of one a month or so back. ",
"Here it is",
" with an image of the Earth s... |
[
"What is the difference between work and play in our heads?"
] | [
false
] | Why is it that doing something like managing spread sheets is boring, and something like playing an MMO is engaging? Or that we hate to do menial factory work of repeating the same action over and over, but we like to play rhythm games like DDR etc.? It seems like the approximately the same action, but working ten or twelve hours a day can lead to stress and poor health while I'm sure many people would have no problem playing games for that long. | [
"\"Play\" activities generally have some sort of payoff that triggers a release of dopamine and endorphins in your brain. \"Work\" activities become a daily grind because you lose that payoff step through repetition. When you play DDR you immediately get the reward when the song ends, when you do factory work you g... | [
"Anecdotally I know people in the service industry have a hard time leaving just because of that. (they usually get tips at the end of a shift) "
] | [
"As a game design student I encountered the great book Man, Play and Games by R. Callois last year and I would highly recommend it as I think it should answer your question or at least give you some insight on this matter.",
"http://en.wikipedia.org/wiki/Man,_Play_and_Games",
"To put it short, if I remember cor... |
[
"Can we learn things while we sleep?"
] | [
false
] | I see videos on YouTube that are a few hours long and are meant to be listened to while sleeping to help learn the language. Does watching these videos help do anything while sleeping? | [
"It is pretty unlikely that you have the capability to learn while sleeping like that. It has been theorized that your brain spends your time sleeping to unpack the information from the day and store it, so it may not be able to learn additional information because it is already at capacity.",
"However, this is a... | [
"There are movies and shows in which a character sleeps with a tape that he is learning, but that is all bogus."
] | [
"Sources? I've actually read a couple studies that suggested there is some level of learning/retention with certain methods. ",
"Pretty sure it's impossible to \"watch a video\" while sleeping, though!"
] |
[
"With no atmosphere to carry a pressure wave, would a nuclear bomb be very effective in outer space combat?"
] | [
false
] | The way I'm thinking of it, the nuke would propel its own matter outwards very quickly (which wouldn't amount to much) as well as a lot of heat and radiation (which spaceships are already good at handling). Also, how well would a nuke work for excavation if buried in a Lunar cave? How well would they really work? | [
"I helped perform the calculations on the EMP Commission Report prepared for Congress. You are correct. A nuke exploded in space (not near the atmosphere) will not create an EMP in the traditional sense. "
] | [
"Your intuition is correct, more or less.",
"Project rho has a good analysis of nukes in space: ",
"http://www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Nukes_In_Space"
] | [
"Nuclear bombs don't explode in the same way chemical explosives do.",
"A conventional explosive undergoes a chemical reaction that produces a lot of hot gas very quickly. A nuclear bomb undergoes a fission chain reaction, producing a lot of high-energy particles, x-rays, gamma rays, etc. which then heat the surr... |
[
"is the Geiger counter not an observer in the Schrödinger's cat experiment?"
] | [
false
] | null | [
"Yes. That is exactly the point of the thought experiment. Schrodinger was trying to point out how silly it was to talk about 'Observers collapsing the wavefunction' in quantum mechanics, when it is much more useful to talk about 'measurements collapsing the wave function'. If a human observer were required in orde... | [
"Schrödinger's cat isn't an experiment. It's a metaphor that was constructed to demonstrate how ",
" quantum mechanics was when the principles were first being discovered. Now it's a metaphor used to demonstrate how ",
" those principles are, despite their being true.",
"Basically, the metaphor is constructed... | [
"this question is okay in my book. "
] |
[
"Advice for Parasitology Paper"
] | [
false
] | Hello , I am currently taking a parasitology course as a part of my biology major in college. We need to write a research paper on a parasite that was not covered in class. Any advice on some interesting ones? We have covered the important parasites in the genera Trypanosoma, Leishmania, Giardia, Entamoeba, Naegleria and Plasmodium. We have also covered Toxoplasma gondii and many flatworms and nematodes. I feel like all the ones of interest have been covered already. Thanks in advance! Note: Cordyceps has been taken already unfortunately. | [
"Look for behavior-altering parasites! Frighteningly fascinating. I wanted to suggest toxoplasma gondii, but a few minutes of googling yields a few possible alternatives. Like ",
"Hymenoepimecis argyraphaga",
"- a wasp that lays its larva on a spider, which then inject chemicals into the spider to alter its ... | [
"How about ",
"Scabies?"
] | [
"Well Dicrocoelium is my personal favorite but looks like you can't do that one. ",
"You can do things like Echinococcus granulosas (Google 'hydatid cysts') or Dracunculus medinensis (this is the one that pokes through your leg in water; also the 'snake' on the medical logos). Or try something that's zoonotic (s... |
[
"If black holes do not emit any light. Why isn't it obvious if there is a super massive black at the centre of a galaxy? Surely there would just be a massive region of space with absolutely nothing present?"
] | [
false
] | [deleted] | [
"You can blot out the sun with your thumb, right? This is because of perspective. Things look smaller at greater distance. Well, the sun is only eight minutes away. The center of the Milky Way is 28000 ",
" away. The reason we don't see a big black spot in the sky is because in those 28000 lightyears, there ... | [
"This. As a DIY example:\nTake a basketball, paint it black, and put it 2 miles away from you (someone who cares can correct for scale). Now fill that 2 miles with flashlights pointed at you. Can you see the basketball?"
] | [
"825,000",
" miles away.",
"Or 3.7 times farther than ",
"The Moon",
"."
] |
[
"Are there any cases where the sudden absence of a species had an effect of the function and economy of that area?"
] | [
false
] | null | [
"The collapse of the northwest Atlantic cod population in the early 1990s had a massive economic impact on the economy of eastern Canada.",
"https://en.wikipedia.org/wiki/Collapse_of_the_Atlantic_northwest_cod_fishery"
] | [
"Since I don't see it mentioned yet, China did a little (/s) experiment back in the mid-1900s... Changed quite a bit. Sparrows, in particular, turned out to be much more important to the ecology than they had anticipated.",
"https://en.wikipedia.org/wiki/Four_Pests_Campaign",
"Edit - Added a /s just in case."... | [
"Look into wolves in Yellowstone.",
"\nHumans took them out. (Think it had something to do with making Yellowstone a more human friendly place.). Decrease or predators lead to increase of prey.",
"\nThe prey eats up more of the environment. And things start to change from there.",
"\nSupposedly, reintroduci... |
[
"What are the smallest measurable unit of time, and smallest theoretical unit of time and at what interval of time are universes “split” in the theory of infinite universes?"
] | [
false
] | null | [
"Astronomy"
] | [
"Astronomy"
] | [
"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",
" because of its open-ended or speculative nature. Please feel free to repost there!",
"Please see our ",
"gui... |
[
"Is the phylogenetic (evolutionary) tree a mathematical tree (acyclic connected graph)?"
] | [
false
] | All the diagrams that I've seen in posters and textbooks seem to say that phylogenetic tree is a acyclic connected graph. However, I couldn't find any literature or articles that claims such relationship. This question can be rephrased as can two separate evolutionary path can result in similar (same) genetic composition? If so, has it been observed anywhere? (I'm guessing assumes affirmative to my question but I could be wrong.) | [
"Even if two lineages converged independently on identical genetic makeup (and this is pretty much impossible) they still wouldn't converge on the graph. This is because phylogenetic graphs don't measure ",
" similarity, they measure actual lines of descent. In practice, genetics is a large part of how we figur... | [
"Phylogenetic trees are indeed directed, connected acyclic graphs. Specifically they are dendrograms as child nodes may only have 1 parent. ",
"With regards the question \"could 2 evolutionary paths converge on the same results\"? In theory yes. In practice never. And even if they did converge on the same solutio... | [
"You need to make a distinction between gene trees and species trees. Gene trees follow the evolution of a single locus (assumed to be non-recombining). That kind of evolution is acyclic or what's called dichotomous branching since as other comments here have mentioned, the chance that mutations could give rise to ... |
[
"What are gravity anomaly maps and how do they work?"
] | [
false
] | I've been reading up on the Chicxulub crater and saw that, besides cenote locations, there aren't any real visible impressions on the earth's surface of the crater/peak rings. The best way to visually observe the crater is looking at a gravity anomaly map. I've tried researching what exactly a gravity anomaly map is and what it's measuring/how it gathers that data. I can tell it has to do with mass, but how would that make it different than topography maps? And how does gravity play into that? I'm just having a difficult time with fully grasping how gravity anomaly maps work. | [
"Things with mass have a gravitational field around them. Higher masses have stronger gravitational fields.",
"Density is a measure of how much mass is in a given volume of thing. Different rocks have different densities. AS s result of this, if you ahve lots of dense rock beneath a location there is a higher gra... | [
"Gravity meters are super accurate pieces of equipment. They can measure tiny variations in gravity from place to place. ",
"To give an example, earth's average gravity on the surface is about 9.81 m/s",
" , or 981 Gal. A decent gravity meter can measure with about 0.000005 Gal precision. These things are usu... | [
"Thank you so much for the detailed response, this really helps!",
"I wonder then if the crater of Chicxulub had more mass and density due the the impact. The story of how those scientists pieced that location together and its significance in the earth's history is super intriguing and I fell down the rabbit hole... |
[
"Who has a greater epigenetic contribution, the mother or the father?"
] | [
false
] | My limited understanding of epigenetics is that it refers to changes in gene expression, not due to changes in the DNA itself but instead via mechanisms such as DNA methylation and histones, and that these changes may be heritable. It is therefore possible for behaviors during an individual's lifetime to alter the gene expression of that individual's offspring. As far as I can tell, both parents contribute to epigenetics. I was wondering, since the sperm and ova are quite different, are the epigenetic changes equally well preserved for both parents? To put it another way, does the prior lifestyle of either parent have a greater bearing on the gene expression of the child? | [
"I think you're asking the question too early - we only know a handfull of imprinted genes, in which the gene from one specific parent is always disabled. ",
"But yes, epigenetic changes are equally well conserved, in that you always get one set of marks from your mother, and one set from your father - however, ... | [
"Sure - first, it's important to know that there are more than one type of epigenetic modification. There are modifications done on the DNA itself (methylation of cytosines, generally), and there are modifications done to the histones around which DNA is wrapped. ",
"While DNA methylation is often used for repre... | [
"Sure - first, it's important to know that there are more than one type of epigenetic modification. There are modifications done on the DNA itself (methylation of cytosines, generally), and there are modifications done to the histones around which DNA is wrapped. ",
"While DNA methylation is often used for repre... |
[
"Where are we right now in the research on longevity? What are the major obstacles to overcome?"
] | [
false
] | I remember reading about how they managed to extend the life of C. Elegans by quite some bit a bunch of years ago. What interesting developments or discoveries on slowing down the aging process have been made since then? | [
"I did Human Genetics at UCL in 2009 and received lectures from one of the leading researchers in Biogerontology - the subject you're currently interested in. He loves the C. elegans and just mentioning the name of it brings me back.",
"I believe at the time (3 years is long research time) they found several prot... | [
"Too much to easily summarize; I'd suggest browsing the last couple of years of archives at Fight Aging!, as that's a running commentary with links to papers and articles as they appear:",
"http://www.fightaging.org",
"Here's a 2011 retrospective:",
"http://www.fightaging.org/archives/2011/12/a-look-back-at-2... | [
"Overcome to achieve longevity. If death is part of natural selection, you could argue that consciousness focused at artificially altering our genes for longevity would be, too. But the discussion is moot as that is a question of morality rather than science.",
"I'm not sure that the link is very much on topic ei... |
[
"How do rocket scientists calculate the trajectories of rockets/satelites?"
] | [
false
] | For example, how do they calculate a launch trajectory so precisely? With things like air resistance, air pressure changes, and even the minute changes in gravity as you pass over different patches of earth. Furthermore, how do they account for all the gravitational influences of the planets while flying through space? There seem to be so many variables that any calculations would be impossible. | [
"I am an Aerospace Engineer by schooling, and you are talking about control theory.",
"Very well understood ",
"orbital mechanics",
" and ",
"aerodynamics",
" give the engineer very well exactly what is expected. The engineer can configure the machine to put the right forces in the right directions at the... | [
"A lot of those forces are not actually that significant (with the exception of air resistance, which can be and is calculated). The forces of other planets are practically negligible unless a spacecraft is doing a flyby, at which point gravitational acceleration is then easily found with g=GM/r",
" Gravitation... | [
"yes. when more detailed measurements are needed (GPS satellite orbits), ground based measurements are used. "
] |
[
"Can computation be done without energy loss?"
] | [
false
] | null | [
"Landauer's principle asserts that there is a minimum possible amount of energy required to erase one bit of information, known as the Landauer limit: kT ln 2",
"Another way of phrasing Landauer's principle is that if an observer loses information about a physical system, the observer loses the ability to extract... | [
"reversible computing",
"Just to be clear, reversible computing is a ",
". There is no reason to think it can't be realised, there is a lot of literature behind the fundamentals, but there is still a substantial amount of engineering problems waiting to be solved. All that is available in the references from th... | [
"With ",
"reversible computing",
" it is possible to beat Landauer's principle, though"
] |
[
"What stops micro chips in humans from being rejected by the body similar to splinters or other foreign bodies?"
] | [
false
] | [deleted] | [
"Thanks for the response :D"
] | [
"I have experience with surgically implanting radio telemetry tags in the abdomen of different species of fish, they're made of metal encased in a cylindrical tube of clear hard plastic. Multiple times I've taken them out of fish (living and dead) that have had them in for a year or two. What I've found is that the... | [
"Thanks for the question prompt OP. Very educational all around! "
] |
[
"Hey Reddit, what fragrance most effectively cuts/counters the smell of formaldehyde/cadavers? [x-post from AskReddit]"
] | [
false
] | Some folks in AskReddit suggested I post here as well to get some lab rat opinions. My girlfriend's in medical school, so she frequently smells like the anatomy lab--sometimes even after a shower. I want to get her a custom fragrance for her birthday, and was wondering if there are particular scents I could layer into the brew to counter this specific challenge of her day-to-day. She normally likes floral scents, though if something spicy or citrus works better, I'd want to include it, no? | [
"Are you trying to counter the smell of the decaying corpse itself, or perhaps the compounds used to preserve it? After being around corpses for a few years, I got disgusted with the smell of formalin.",
"If you can find a place to get a sample, I would offer Boucheron for women: (\"Launched by the design house ... | [
"Here's what I found on a med student's forum (",
"http://forums.studentdoctor.net/showthread.php?t=727250):",
"\"General tips (from the forums and elsewhere):",
"* buy extra, and change out of, your scrubs!\n* For the hands, I recommend double gloving. Some people put soap on in between the gloves, but that'... | [
"She says that the cadavers last pretty much all term, so I guess that means preserving agents, yes. Which is mainly...formalin, you said?"
] |
[
"Seriously, do I have ADD/ADHD?"
] | [
false
] | null | [
"Medicine"
] | [
"Medicine"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"medical or safety advice",
"/r/AskScience",
"guidelines",
"If you disagree with this decision, please send a ",
"message to the moderators."
] |
[
"In this day and age, with all this negative criticism, why aren't we seeing more operating systems created from the core/kernel instead of just alternative distributions? Is it really so hard that we're still relying on 20+ year old core-coding?"
] | [
false
] | null | [
"This is an answer targeted at a layman, so I've simplified a number of complex topics substantially.",
"I'm going to assume that you are talking about 'personal computers' - Desktops, Laptops and the like. Portable computers and embedded computers are another interesting topic, as are very large computers but I'... | [
"reinventing a new kernel from scratch would be a waste of time.",
"Reinventing a new kernel from scratch for commercial reasons is very likely to prove a waste of time (or at least very expensive and risky). On the other hand, implementing a new kernel (or a new operating system paradigm) for academic reasons ca... | [
"because the kernels we have now are not actually all that old. the linux kernel is in constant development and is very good. reinventing a new kernel from scratch would be a waste of time."
] |
[
"Historian with a couple questions on disease evolution in the 1400s."
] | [
false
] | I have some questions on the state of disease at the time or European encounter of the Americas. Smallpox and several other European diseases as I understand it evolved in part due to the proximity of Europeans to domestic livestock. I'm guessing this has to do with animals like pigs that root in their own wastes. Is this pretty much correct? Native Americans had dogs mainly and they are more or less clean animals (plus since they aren't packed together, raised as food). Some might argue the concentrated numbers of Europeans in cities, but there were several cities in what will be Latin America that had similar populations as those in European cities. | [
"For the case of smallpox, it's actually thought to have come from a rodent virus between ",
"16,000 and 68,000 years ago",
" in Africa. Since it's very unlikely that the same virus would evolve twice, the isolation of America meant this virus would not reach it until transmitted by humans (much much later on).... | [
"Thanks, that makes sense on the smallpox idea. If we peg that somewhere around the 16,000 years ago date, the initial groups crossing the Bering Land Bridge would have been crossing into the Americas at the same time smallpox was making its debut. ",
"It also makes sense on the Native American front. There wa... | [
"I'll have to take your word for all that, but it seems I've helped :). Also pretty interesting, even though I'm a scientist now, I've always enjoyed history, so nice to combine the two"
] |
[
"A few years ago it seemed that Ebola was apocalyptic, yet we stopped it. How were we successful is stopping it from becoming a global pandemic?"
] | [
false
] | in* | [
"No one expected it to be a global pandemic, except for the people who profit from panic (i.e. the news media).",
"And we didn't stop it. Another Ebola epidemic is going on right now, with no signs of being controlled, and the news media have decided that they don't care, so you don't know about it.",
"WHO Stat... | [
"The only piece of good news on this Ebola outbreak is that the vaccine seems to work really well. ",
"The data are clear: Ebola vaccine shows ‘very impressive’ performance in outbreak (Apr 12, 2019)",
"The vaccine became available very late during the last big outbreak, and since the cases were already fading... | [
"With pandemics, a key thing is isolating those who’ve been exposed into a closed area, and treating them there as possible. The idea is similar to a forest fire; let the problem burn itself out. ",
"If the contaminated population is allowed to spread and infect new populations, it will keep spreading. Quarantin... |
[
"How accurate is \"Breaking Bad\"?"
] | [
false
] | EDIT: To clarify, I mean the "chemistry" that is discussed/portrayed | [
"As a chemist there have been a couple of other occasions when I've noticed things that aren't quite right, but I forget them now. The last one I remember is how their final product appears - a giant single crystal 'glass' slab in what appears to be a baking tray. Anyone who has ever tried to grow crystals will tel... | [
"Maybe some specifics would help (OP and others, feel free to add/edit):",
"Can you dissolve a body with HF?",
"Would the \"Heisenberg method\" of producing Methamphetamine, really be superior to other methods ie. using Sudafed?",
"Is it that easy to make ricin?",
"Etc.."
] | [
"If you just write down the recipe and follow instructions you're most of the way there, but there are of course some subtleties that come with practice and experience.. hence Heisenberg is the man, but hence mexicans can still cook meth in their kitchen at home. I guess it would be like asking a random person off ... |
[
"Why is evolutionary psychology frowned upon?"
] | [
false
] | [deleted] | [
"You nailed it when you described how untestable yet plausible these ideas are. Popular notions can take hold very quickly because they make sense to people. This doesnt make them right or even science though. ",
"Evolutionary psychology can test some of their claims and assumptions, but there are quite a few fol... | [
"I've heard that many psychologists are dismissive of evolutionary psychology. ",
"Actually, it's many scientists in general. Some EP researchers are fine. However, a lot (I'm not saying the majority) are not. Why?",
"They retrofit ideas and concepts now to something that cannot be studied and usually do not ha... | [
"I think evolutionary psychology's best purpose is in giving lay persons a framework around which to understand medical and psychological phenomenon and scientific research. For a scientist, having an evolutionary psychology perspective doesn't really help much. Before becoming an AskScience panelist I never thou... |
[
"how do even-dimensional waves behave?"
] | [
false
] | I recently read about a theoretical space with more than 3 spatial dimensions. I'm interested in the sound waves propagation part, it's basically saying that in a space with an odd number of dimensions (like ours) sound would behave as it usually does, BUT with a space with an even number of dimensions things would be different. It's giving an example with waves propagating on a 2D surface (the classic pebble in the water), saying waves “double back” on themselves. can anyone explain why does this happen? why in 2D, and how would it be in 4D? How would a 4D wave propagation pattern look like crushed down in a 3D tesseract? | [
"WARNING: I reached the character limit for my original explanation, so I am splitting into two posts. The second is found as a reply to this one. The explanation is long, but your question is not exactly simple to answer. This first post contains the maths and the second post answers your questions and comments us... | [
"So now let's answer your questions and comments. (I reached the character limit for the original post.)",
"I'm interested in the sound waves propagation part",
"The discussion here holds for all waves. In the math above, the speed of the wave is just 1. But we can add a multiplicative constant to the equation ... | [
"First of all, a huge THANKS for your time and for your awesome reply!\nLet's get cracking!",
"I can't tell you how you would perceive a 4D wave, because we just don't live in a 4D world, at least not in world in which we can perceive 4 spatial dimensions. Also, a \"tesseract\", by definition, is just a 4D cube. ... |
[
"If i stare at a specific point in a pattern, why do the surrounding points disappear?"
] | [
false
] | I was staring at a line in my tile floor, and the lines around it disappeared as i kept my focus. | [
"I think this would be better placed in neuroscience, because it has to do with how your brain processes information. ",
"It is due to something called ",
"Troxler's Effect",
". you can read about this on the wiki page, but basically the sensory neurons get \"used\" to the unchanging stimulus and so begin to... | [
"To add onto this: The peripheral vision which encompasses the surrounding disappearing lines uses rods to process the visual information. Many rods can be tethered to one ganglion cell leading to the optic nerve. The convergence of many rods onto one cell helps you see your surrounding a little better when your br... | [
"Neuroscience and cognitive science will provide explanations at different levels of representation here, which are certainly equally \"valid\" or explanatory.\nFrom a cognitive or perceptual point of view, I would point out visual attention that is known to modulate even early-stage visual processing, and that is ... |
[
"Is there an advantage, from an engineering point of view, in having two separate \"on\" and \"off\" switches in a circuit (or a device) rather than a dual-function switch?"
] | [
false
] | null | [
"Separate on and off switches is the same as two switches IMO. ",
"In memory operations (and many other cpu pipeline operations, or in general Boolean logic) you can have a third state: ",
"don’t care",
". ",
"This is used to speed up addressing or make it more general, ",
"for example",
". "
] | [
"Thanks - your example reminds me of how we would approach this problem in software development. Having separate \"off\" switches gives you the ability to give controls to the end-users."
] | [
"I can see the application of a second switch in a logic gate. I was more curious about the electrical/electronic machines world. "
] |
[
"Is anything really possible? Such as anything I can imagine scientifically be created?"
] | [
false
] | null | [
"Examples- superman \nPokémon \nTeleportation\n6 foot walking taco that shits ice cream. "
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"If you disagree with this decision, please send a ",
"message to the moderators."
] | [
"Well how do I go about posting this question?"
] |
[
"Can anyone explain the weak nuclear force to me?"
] | [
false
] | I've read around a bit online, and have a understanding of the weak nuclear force, but a few points are kind of baffling me. For instance, where do the W and Z bosons "come from", and what precisely is happening when a quark's flavour changes? Furthermore, the W and Z bosons are said to be elementary particles, yet in beta decay (for example), the W boson decays into an electron and antineutrino. What's going on here? | [
"Basically, it's like a tennis ball that when it hits something, the thing it hits transforms.",
"That's my understanding, anyway.",
"What's going on here?",
"Basically what's happening is conservation of energy. The energy from the boson is converted into an electron and an antineutrino. Quantum numbers are ... | [
"W and Z bosons comes from particles that have weak charge. This is like asking \"where does light (photons) come from?\" Photons come from particles that have electromagnetic charge. And yeah, as far as we know W and Z bosons are elementary, but just because they can decay into two different particles doesn't mean... | [
"This won't answer your question but I did ask about the W and Z bosons last week. ",
"This may be fun reading",
" until one of our resident particle scientists show up.",
"You also may want to sort this subreddit by new and dig around the posts from the last two weeks (there aren't many). There's tons of rea... |
[
"Why do most depression medication give side effects that include suicidal thoughts?"
] | [
false
] | [deleted] | [
"That is a really, really good question and the short answer is that we just don't know yet. It seems to be due to two different, but related effects: anti-depressants have a \"lag-phase\" of a 3-4 weeks before they really become effective and they can lead to wild mood swings in patients with underlying bipolar ... | [
"The really important thing to remember here is that if even teeny tiny percent of the clinical trial reports suicidal thoughts during the course of the trial for the drug, then the drug company has to report it in their advertising. These suicidal thoughts may or may not have been related to the effects of the dru... | [
"Unfortunately I can't offer your guys proof that what I am saying is true, but my father, who is a psychiatrist, has confirmed this. The medications don't \"cause\" suicidal thoughts, so much as coming out of the depression but still having it a bit is a critical period for this."
] |
[
"How much water is in a cloud?"
] | [
false
] | Since clouds are dense enough that we can see them and dense enough to block sunlight, how much water would I have if I condensed the vapor from a cloud that's, let's say, 3,000 cubic meters into liquid? (Not sure if that's a reasonable cloud size.) | [
"You can see clouds not because they are \"dense\" enough, but because they have tiny particles (dust, ice, water droplets) that scatter light. A sheet of glass is much denser than a cloud, but clear glass is also more transparent.",
"This is a pretty complex subject, but a couple easy things to remember are:",
... | [
"You heard wrong: the orders of magnitude aren't even close. ",
"Only 0.001% of the Earth's total water is in the atmosphere",
", and only some of that is in clouds (the rest is water vapor)."
] | [
"You heard wrong: the orders of magnitude aren't even close. ",
"Only 0.001% of the Earth's total water is in the atmosphere",
", and only some of that is in clouds (the rest is water vapor)."
] |
[
"Why do we observe constellations from Earth?"
] | [
false
] | Astronomers of antiquity observed more or less the same constellations as we do today. How is this so, given Earth orbits the sun, which in turn orbits the galactic centre (and the galaxies move further away from each other!)? Are the stars in the major constellations in our 'arm' of the Milky Way, or at least a neighbouring arm, and so move with us around the galactic centre? I am in London and see a limited amount of stars given smog etc, but lately I noticed Orion, viewed two nights in a row and directly to the South can appear differently e.g. Narrower or taller which suggests the configuration of Earth and the stars does slightly morph. Is it fair to say that we only see a glimpse of the stars' configuration, given our ~70-80 year lifespan as compared with that of stars and the cosmos (hence it appears as a 'snapshot' to us mere humans)? Thanks in advance to my favourite reddit in the cosmos! EDIT: more detail about observing Orion | [
"Astronomers of antiquity observed more or less the same constellations as we do today.",
"Actually, we can see from star charts made by the ancient Greeks that the constellations have changed shape slightly since then. Edmund Halley was the first to notice it. Here's a nice little explanation of constellations: ... | [
"Yeah, and to give a scale, the stars with the ",
"highest \"proper motion\"",
" are moving at a few arcseconds per year. 1 arcsecond per year for 2000 years is only about 0.5 degrees of change.",
"Most stars move much more slowly than that. ",
"Here is an animation of the fastest star over 20 years of ob... | [
"they are moving, and they do change shape . . .over time . . . a LOOOOOONNNNNNNGGGGGGG time. Even with everything moving around as fast as it does, it still takes hundreds of years for us to notice a change. Go to starryNight or any other star software, set the time flow as fast as you can and you will see the s... |
[
"A two part question on lighting dimmer switches..."
] | [
false
] | When you have a light on a dimmer switch that is turned almost all the way down, is it using less electricity or is some of the energy "wasted" by the dimmer? The dimmers in my house give off some form of EM interference which is picked up by audio recording equipment so presumably some of the energy is "wasted" in this manner. When my lights are dimmed, they give off a very high pitched (Some people can't really hear it so it's well above 10kHz) buzzing noise. What causes this? | [
"http://home.howstuffworks.com/dimmer-switch.htm",
"I'm not an engineer, but the 'old way' appears to simply be increasing the resistance (which would produce more heat). The new method takes advantage of alternating current to switch on the circuit for a fraction of the phase. Maybe this switching is causing t... | [
"So the buzz is caused by the filament being ",
" moved? By what mechanism is the filament moved? Some kinda induced magnetism? 16-18kHz sounds about right. Good to know that I can still hear up that high but bad to know I've got ",
" cheap dimmer switches..."
] | [
"This sudden shift in voltage changes the magnetic field abruptly, which can cause the filament to vibrate -- it's rapidly drawn to and repelled by the metal arms holding it in place. In addition to producing a soft buzzing sound, the abruptly shifting magnetic field will generate weak radio signals that can cause ... |
[
"Is there a material with an electrical resistivity of 10^7 to 10^8 Ohm-m?"
] | [
false
] | null | [
"The closest thing I can think of is PVC which has a resistivity of about 10",
" You could maybe coat a sheet of aluminium foil with pvc, which could give you both the right thickness and resistance."
] | [
"Some type of doped glass might work. Glass itself has around 10",
" doping could bring that down a bit. \nAlso consider what temperature you want to run it at. According to this, the resistivity can change dramatically: ",
"http://www.memsnet.org/material/glasssio2bulk/"
] | [
"Thanks, I'll look into it! Where did you get that info on PVC's resistivity?"
] |
[
"Is a coma \"restful\"? If I were hit in the head and knocked out for eight hours, would I wake up feeling like I had slept for eight hours?"
] | [
false
] | [deleted] | [
"No, comas are not restful.",
"Sleep has an actual structure to it. One cycles through non-REM stages I, II, III, IV, and back down, then through REM and the same thing all over again. Whatever the brain is actually doing during this time, it's replenishing you.",
"A coma is an abnormal state of unconsciousness... | [
"Well I'll be honest, it's a science question that wouldn't be hard to hit up google with."
] | [
"Well I'll be honest, it's a science question that wouldn't be hard to hit up google with."
] |
[
"Why can't some build immunity against allergies?"
] | [
false
] | I have basic immune system knowledge but not enough to answer this question. I'm pretty sure that the only thing that should make an allergy different from other antigen responses is that it's physical, but why don't memory cells help during the second response, building eventual immunity? | [
"It's a good question. My answer is hazy, because to be honest, the knowledge is a bit hazy. ",
"B cells are not a homogenous population. There exist three main types of B cells: B1, B2 and marginal zone B cells. B2 are what we think of as \"classical B cells\". All three types can form plasma cells and produce a... | [
"Thank you! "
] | [
"It's not my area of expertise - I had a quick search as I hadn't heard it before and:",
"Compared with participants who regained their allergies, the individuals capable of eating the food without a problem had roughly twice as many peanut-specific regulatory T cells, a type of immune cell that helps to dampen a... |
[
"What, if anything, limits electromagnetic radiation to gamma rays on the high end and radio waves on the low end?"
] | [
false
] | Are there waves that are just so big that nobody has experience them fully in the human experience? I mean long, long waves that haven't passed through entirely Earth yet with one frequency over millions of years? I'd bet there's some fundamental constant that bounds them with an upper and/or lower limit, but like I said I'm just guessing here. I suppose the fact that at some point you're not gonna be able to get any less distance between the waves due to planck lengths and whatnot which will keep them from going higher energy than gamma. | [
"There is no physical constraint on the longest possible radio wave, but we use the same term (ELF, or extremely low frequency) for all radio waves 3hz or below. Gamma rays have an extreme upper bound in frequency where their wavelength is the same as the planck length, and at 1.022 MeV, photons interact with matte... | [
"I thought planck's length would be a limit?"
] | [
"Plank units are too often cited as some kind of limitation. Really they are just a possible point where our current understanding of physics ends, not some place where nothing is allowed."
] |
[
"How efficient are antennas in comparison to florescent or LED light sources?"
] | [
false
] | RF and visible light are different colors of the same phenomena. So how different are antennas to LEDs? If I was able to see visible light as well as 100MHz light, would a 60W radio amplifier connected to a good antenna shine as bright as a 60W LED light bulb? Bonus question: Parabolic metal antennas work as curved mirrors. Do we know of a material that works with RF the same way as glass does with visible light? Can we make RF lenses (see-through rather than reflective)? | [
"Interesting question.",
"So, antennas are very efficient in certain configurations. Again, using your example, a single-bay FM radio antenna rated for up to 1kW would be about 45% efficient. That's really bad, as far as antennas go ... more in a bit.",
"But the circuits that drive the antenna are less efficien... | [
"Well satellite dishes reflect the RF into the receiver. I was thinking of something that refracts the RF akin glasses. "
] | [
"In theory, yes. but I haven't been able to identify any materials that have Fresnel indexes cataloged at VHF frequencies. ",
"This could be because the \"slit experiment\" is more difficult to run outside the visible spectrum, because you can't use a piece of paper, a prism and a protractor to figure out the re... |
[
"What causes head-rush when we stand up too fast? What do we \"see\" when this occurs?"
] | [
false
] | As the title asks. When you stand up too fast from a sitting/laying down position and your vision goes dark and you start to see "images". What causes this? | [
"When you are sitting down you are a bit compressed and when you stand up quickly, your blood suddenly has to fill the parts that didn't have so much blood due to the compression. This causes a drop in blood pressure resulting in the brain not getting enough blood, so it starts shutting down, which you feel as a he... | [
"Orthostatic Hypotension",
" is the technical term. "
] | [
"Yup, orthostatic hypotension. ",
"The lower blood pressure and blood flow in your head causes the visual problems as well, there's temporarily not enough oxygen to process the signals that come from the eyes correctly."
] |
[
"Where is the Andromeda galaxy visible with the naked eye--anywhere on Earth, from the ISS, from the Moon, from the dark side of the Moon, etc?"
] | [
false
] | I know that it it's nigh on impossible to see it--despite it's size. But can the astronauts on the ISS see it, where the Apollo astronauts able to see it, could it be seen on the dark side of the Moon, would you have to get further from the Sun, what would it take? | [
"It is visible from pretty much anywhere in the northern hemisphere that's reasonably dark. It won't be the brightest thing out there, but it'll be a reasonably bright and noticeable fuzzy patch in Andromeda, near Cassiopeia. Because it appears fairly near the north celestial pole, it's not visible from far souther... | [
"From ",
"the Wikipedia page",
":",
"At an apparent magnitude of 3.4, the Andromeda Galaxy is one of the brightest Messier objects,[15] making it visible to the naked eye on moonless nights even when viewed from areas with moderate light pollution. "
] | [
"I'm not sure what you're asking. For it to be as bright as the Milky Way is to us, you'd need to be in the spiral of Andromeda."
] |
[
"Are there any attempts to explain the cause/source of the existence of newton's laws, if so then how successful are they?"
] | [
false
] | null | [
"Yes, Lagrangian and Hamiltonian mechanics explain Newton's laws as arising from optimizing a quantity known as the \"action\" (which in many common systems would the be the difference between the kinetic and potential energies). These theories have been ",
" successful, to begin with they are much more easily ge... | [
"...energy and momentum, which are always conserved.",
" always."
] | [
"Calling it the \"principle of extreme action\" is misleading though since the solutions to the Euler-Lagrange equations do not necessarily give an extreme value of the associated functional. (This is also why \"principle of least action\" is misleading.) Solutions of the EL equations are guaranteed only to give st... |
[
"Growing Hopper Crystals?"
] | [
false
] | I got a batch of pure (99.9% grade, i believe) bismuth, and I want to melt it down to make some . I've read some on how to grow them, but nothing with a scientific explanation how to make them the best. Any help would be appreciated. | [
"I'm not sure you can do much better than listen to the people who've already done it. Even research papers might not amount to much more than \"this is how we did it\". ",
"See, growing crystals is a pretty difficult topic. A whole field in itself (there's even a \"journal of crystal growth\"), because there are... | [
"I attended a lecture called \"none of your bismuth\" at burning man... it was burning man, so I don't remember every detail, but I can say for certain that it was done in the middle of a dust storm, with a camp stove. You shouldn't have any problem pulling it off at home."
] | [
"Thanks for the response. From what I've read, the oxidation creates that shiny outer coating, so when would I expose it to oxygen if I melt it down in a surrounding with inert gas?"
] |
[
"Why are particle accelerators like the Large Hadron Collider in Europe built underground?"
] | [
false
] | I imagine that particle accelerators would be a lot cheaper and easier to build if they were above ground. | [
"There are a few reasons that particle accelerators are generally built underground. The main reason of course being ",
"Synchrotron radiation",
". In addition, building underground makes it easier to achieve stable thermal conditions which matters more than you might expect.",
"You could build an above gro... | [
"Also: cosmic rays, and in the case of the LHC, above-ground would have to contend with major roads and villages. ",
"It's also worth noting that synchrotron radiation isn't a very big deal in proton accelerators (as opposed to electron), though radiation is still a significant issue in the case of a beam stabili... | [
"17 miles in circumference, under the french/swiss countryside, under villages and major roads, etc. "
] |
[
"Some years ago I watched a video showing the effects of the earth slowing its rotation and eventually stopping. (Basically chaos) My question: Would there be similar effects if the sun slowed down or stopped its rotation?"
] | [
false
] | null | [
"If the sun were to suddenly stop spinning there would be no change in the orbit of the planets at all. It wouldn't even largely decrease radiation emotions, although it may decrease light by a negligible amount due to the loss of efficiency for convection within the sun. But as ",
"u/SAR-Paradox",
" pointed ou... | [
"Presumably there would be an increase in rate of fusion as gravity would no longer have to provide a centripetal force to keep the sun bound, so radiation pressure would need to up its game to match this, but I have no idea whether this effect would be significant."
] | [
"What would this \"chaos\" be?"
] |
[
"Do the atoms and/or electrons in a wall *feel* anything when a radio wave passes through them? i.e. do they move at all?"
] | [
false
] | null | [
"Yes. If you drive a piece of material with a sinusoidally-varying electromagnetic wave, the medium will respond with a time-dependent polarization and magnetization. This corresponds to the charged particles inside the material oscillating back and forth, producing tiny instantaneous electric currents and dipole m... | [
"But the loose interaction as a photon passes by is what leads to an index of refraction.",
"http://laser.physics.sunysb.edu/~jennifer/reference/index/indexrefraction.html",
"Waves that are encountered by any kind of matter will have a transmission of energy. This will cause the electrons into a vibrational mot... | [
"But the loose interaction as a photon passes by is what leads to an index of refraction.",
"http://laser.physics.sunysb.edu/~jennifer/reference/index/indexrefraction.html",
"Waves that are encountered by any kind of matter will have a transmission of energy. This will cause the electrons into a vibrational mot... |
[
"How can I access scholarly articles?"
] | [
false
] | [deleted] | [
"You could try asking on ",
"http://www.reddit.com/r/scholar",
" , it's a whole sub-reddit for requesting articles"
] | [
"Case closed!"
] | [
"You might want to try the local community college. You would have to go to their library, but you can email yourself the PDFs."
] |
[
"Do, or rather, can animals choose whether or not they want offspring?"
] | [
false
] | Do some animals reject mates for life and remain celibate out of choice? | [
"I'm not aware of \"celibate,\" but zoopharmacologists (people who study animal use of medicines) have found that elephants will eat the bark of a certain tree to induce labor and/or early-terminate a pregnancy, and I've heard of other species re-absorbing their young when the local dominant male gets supplanted so... | [
"I dn't know about animals in the wild, but when kept as pets, many birds will not reproduce unless provided with an appropriate place for a nest. Not sure if you can really consider it their choice, but at least this shows that they know they should only lay eggs when they find the right conditions."
] | [
"In general, this would be ",
" (especially given that out-crossing is demonstrably more favorable than inbreeding). However, a genetic mutation or injury could potentially inhibit those standard behaviors.",
"As noted in some of the other comments, there are certainly cases where animals receive environmental ... |
[
"Why does the density of the universe have anything to do with its shape?"
] | [
false
] | According to this posted on TIL, the geometry of the universe is decided by its density and that because matter is not dense enough to cause a big crunch (or at least it does not appear to) we are therefore led to conclude that the universe is most likely flat and infinite. Why is that conclusion valid? Why can't the universe just be large enough (but finite) that the density of matter is equivalent to or less than what would be required for it to be infinite and flat? I don't see what does density have to do with the geometry of the universe at all? | [
"In general relativity, geometry and energy-momentum are inextricability linked. The fundamental equation of GR, G",
" = 8pi T",
", expresses this connection. Consequently, a dense, homogeneous, expanding universe must be closed, and a thin one must be open.",
"Note: I'm ignoring the cosmological constant (... | [
"The mechanism for gravity is actually the curvature of spacetime. The more dense a spot is, the more the space there gets depressed, and the more \"attraction\" you get.",
"We realized that there is a number, represented by Omega, that determines if our universe is heavy enough for a big crunch or not. If omega ... | [
"I don't think it could ever be infinite. It just means that the universe will expand and expand and entropy will increase and increase."
] |
[
"If a point is translated a unit either up, down, left, or right, determined randomly, in a two dimensional cartesian plane every second for an infinite amount of seconds, what position would it approach as the amount of seconds approaches infinity?"
] | [
false
] | I envision the origin (assuming it starts at the origin) to be the most likely destination for the point after n iterations. However, I doubt that if I carried out this experiment 1000, 10,000, or 1,000,000 times that the point would fall anywhere close to the origin. Is there even an answer to this question? | [
"The average displacement of a 2D random walk is zero, but the root-mean-square displacement is proportional to the square root of the number of steps. This lets you define a \"radius of gyration\" which tells you the average size of a random walk."
] | [
"It's a question of combinatorics. ",
"Handwavingly, you'd count the number of possible paths of a certain length that will let you return to 0 and contrast that with the total number of paths of that length. As it turns out, in 1d and 2d the asymptotic behaviour of these quantities leads to a probability of 1 th... | [
"Also, for a 2 dimensional random walk, with an increasing number of steps the probability of returning to the origin approaches 1 (despite the RMS distance from origin increasing).",
"However, this isn't true for 3 or more dimensions."
] |
[
"If the chemical trypotran(can be found in milk, and banana's) has an effect on the production of dopamine in the brain, wouldn't that actually have the reverse effect on the body by not producing it's own natural level?"
] | [
false
] | [deleted] | [
"First off, you are talking about tryptophan, the amino acid? What is the exact question you are asking?"
] | [
"I suspect Thrownaway200 is talking about this:",
"http://en.wikipedia.org/wiki/Tryptophan#Use_as_a_dietary_supplement_and_drug",
"Specifically:\n\"... Tryptophan has shown some effectiveness for treatment of a variety of other conditions typically associated with low serotonin levels in the brain.[27] ...\"",
... | [
"Tryptophan (not ",
") is a chemical precursor to 5-HTP, which is a chemical precursor to 5-HT, aka serotonin (not ",
"). Here's a ",
"fancy pic",
" from wikipedia.",
"Ingesting foods that contain tryptophan can increase the available serotonin in you brain, but it will not adversely impact your body's a... |
[
"Is it possible for a tornado to destroy a skyscraper?"
] | [
false
] | Reading a story related to the EF5 tornado that hit Moore, OK. on Monday, someone in comments said that these types of tornadoes could destroy skyscrapers in midtown Manhattan. Could an EF4 or EF5 actually destroy the structure, or would it just cause all windows to be blown out? Thanks. | [
"Depend's on your definition of \"destroy\", it could surely do significant damage but I do no know of any collapses due to tornado. The damage will be greatly dependent on the building geometry, lateral force resisting system, surrounding buildings and terrain and can be difficult to predict. ",
"Let's first t... | [
"I know this is probably a stupid question, but could you give me a little more insight? I'm not an engineering minded guy.",
"On 9/11, hijackers flew jumbo jets into the world trade centers. These were metal objects, filled with jet fuel, and they collided with the buildings at 400+ mph from what I understand. E... | [
"The frame of the Metro Tower in Lubbock was ",
"severely damaged",
" in a 1970 tornado."
] |
[
"Are the relativistic time differences between clocks on the Earth and the clocks in GPS satellites, due to the reduced gravity 12,500 miles up or the speed at which the satellites travel or both?"
] | [
false
] | An object that travels faster relative to another has an internal clock that 'runs' slower, while an object closer to a gravitational source does the same thing, so which of these (the distance from the gravitational center of the Earth or the orbital speed) has the greater effect on the clocks in the GPS satellites? | [
"The velocity causes the clocks to fall behind by 7 microseconds per day. The lower gravity causes them to go faster by 45 microseconds per day. Net result is that they go about 38 microseconds per day faster than clocks on the surface. So the gravity has a bigger effect and also the two effects are in opposite dir... | [
"The clocks on the satellites run slower than those on the ground by about 7 microseconds per day due to the (special) relativistic effect of their high speed. They run ",
" by about 45 microseconds per day due to the (general) relativistic effect of the \"reduced\" gravity."
] | [
"Both, but the gravitational effect is stronger."
] |
[
"Can metallic objects passed through and electromagnetic field cause a measurable differance?"
] | [
false
] | [deleted] | [
"If I'm not mistaken this is how guitar pickups work."
] | [
"Not really sure what you're talking about here. What is the setup you're envisioning here? What is the battery hooked up to? In general, yes, metallic objects brought through/into an electromagnetic field will be detectable - assuming relative motion between the object and the field - due to the induction of curre... | [
"I don't know enough about the properties of batters as far as their behaviour as a voltage source goes, but monitoring the voltage is probably not the best way to do it; you'd be better off measuring the current. You should indeed see a drop in the current when you sweep the electromagnet past a metallic object."
... |
[
"With the knowledge we have at hand, what will the earth be like in 100 years?"
] | [
false
] | I'm thinking along the lines of developments in technology, including nano-tech and the development in neuroscience in conjunction with replacing limbs and some senses, e.g. sight, or even enhancing the human body as it is, and how our push forward will affect us socially, as well as affecting military protocols and acts of war. Will war, for richer nations, be solely based on robotics, drones, and biological agents, instead of the use of ground troops? And what about environmentally? What would happen if one summer, the ice caps DID melt, and year upon year, ice continued to disappear around the spring/summer seasons? How would that affect our coastal regions and what action would it spurn? | [
"And to make up from my earlier snarky comment:",
"What was life like 100 years ago?",
"Locomotives and coal fired ships were the best transportation you could get. Automobiles, electricity, and radio were in their infancy. Television wouldnt be invented for another 2 decades. The Internet as we know it would t... | [
"I do think that we will plateau relatively soon, every great leap ends with a long period of same old same old until the next great innovation.",
"Who knows what that will be."
] | [
"I can't account for all the changes that we will see in 100years, but on the basis on the environmental changes I can come with some theories.",
"first: I'm at the moment doing a Master in Environmental and landscape geography at the University of Bergen under professor Anders Lundberg (the master thesis is abou... |
[
"Do we see any stars from out of the milky way, or maybe whole galaxies, with the bare eye?"
] | [
false
] | null | [
"You can just about make out the ",
"Andromeda galaxy",
" with your naked eye (if you live in the northern hemisphere). You will probably need to travel to a very dark area to do so but it is relatively easy to find, have a google for a guide if you are interested, it is near the constellation Cassiopeia (the b... | [
"And to complete the answer - no individual stars are visible with the naked eye which are not part of our galaxy."
] | [
"also, even the stars we do see are only from a very small fraction of our galaxy."
] |
[
"We hear a lot about new ways to generate electricity, such as fusion. But are there any new developments in the way we harness heat and transform it into electricity?"
] | [
false
] | I hear a lot about fusion and "new-generation" fission reactors being potentially revolutionary in the way we generate electricity. However, it is my understanding that it will be a new way to generate heat, while we will still use old-school steam turbines to convert heat into electricity. My question is, are there any theoretical or "moonshot" ideas of a more efficient way to electricity | [
"It’s a really good question that basically comes down to thermodynamics, how to use energy in the form of heat to do work. There are very few losses in the actual generator, and likewise you simply combust natural gas, that can be done quite efficiently (nat gas furnaces are efficient into the upper 90s of percent... | [
"Very nearly all forms of electrical generation come from a heat transfer. This includes fossil fuels, fission, fusion, many types of solar (but not all), geothermal, and I'm sure I'm missing others. Exceptions:",
"-Windmills: kinetic energy in the air to electricity",
"-Hydroelectric: varies, but in dams it's ... | [
"Fuel cells basically do direct chemical energy to electrical energy conversion, and therefore should theoretically be more efficient than extracting that energy with a combustion step. ",
"I believe that modern hydrogen fuel cells, which are approaching 60% efficiency, capture a greater percentage of the chemica... |
[
"How fast would a metal object have to move through Earth's magnetic field to generate significant electrical current?"
] | [
false
] | Say you have a 10 meter long conductor. How fast would it need to move to generate a few milliamps? Enough to light a low power LED? | [
"Nope, but I just went searching for it. Turns out there's a wikipedia page about them: ",
"Magnetorquer",
"A magnetorquer or magnetic torquer (also known as torque rod) is a satellite system for attitude control, detumbling, and stabilization built from electromagnetic coils. The magnetorquer creates a magnet... | [
"I'm pretty sure some satellites (or at least designs for satellites) actively interact with the Earth's magnetic field (by inducing currents) to torque themselves, in order to save, or even slowly reset their gyros."
] | [
"I'm pretty sure some satellites (or at least designs for satellites) actively interact with the Earth's magnetic field (by inducing currents) to torque themselves, in order to save, or even slowly reset their gyros."
] |
[
"How can dark matter be huge a substantial part of our universe but we can't see or detect it?"
] | [
false
] | null | [
"In much the same way as how bacteria and atoms were a huge, substantial part of our day-to-day lives but we couldn't see or detect them either.",
"We don't currently have the means to meaningfully observe and explore dark matter. That doesn't mean it can't possibly exist. It just means our understanding is limit... | [
"Thanks, helps me understand it a lot better. "
] | [
"We can detect it by its influence on other things as ",
"/u/astri-oh",
" pointed out. We can't see it because it's thought not to interact with light, therefore it does not absorb or emit."
] |
[
"Do imaginary numbers have any practical applications?"
] | [
false
] | null | [
"Of course, why wouldn't they? They're just as real as normal numbers, which is to say not at all. Complex numbers are a nifty way to encode 2D translations, 2D rotations and scaling compactly as addition and multiplication. Very convenient. ",
"Electrical engineering, fluid dynamics, quantum mechanics and much m... | [
"Electrical engineers for its rotational properties to study the periodic behavior of circuits. (See ",
"this",
").",
"Fluid dynamics uses it because you can encode fluid motion as a differentiable function on the complex plane. (See ",
"this",
")",
"Quantum Mechanics uses it because quantum states can ... | [
"If you have an alternating current, and a circuit with such interesting components as capacitors and inductors as well as resistors, then you can model the voltage as V0 e",
" instead of V0 cos(wt). The real voltage is the real part of the complex voltage, of course. But why do this? Because then, inductors and ... |
[
"So we know how dominance and recessiveness work for Mendelian traits because we were taught about Punnett Squares in school. But how do dominance and recessiveness work for more complex/polygenic traits?"
] | [
false
] | null | [
"For any given gene we don't really know how dominant or recessive various alleles will be, as for most genes we don't even know what they do yet, or only have a very rudimentary understanding of what they may be involved in. In general, the extreme dominant/recessive traits we study in school are rare and most fun... | [
"The same way they work for everything else, except that you also include epistasis and other interactions. So let's take height, for instance. Let's say there are 200 genes that dictate it. In a simple model, just imagine that each gene contributes some number of inches or fraction thereof to your total height, an... | [
"Before I start forgive me for any inaccuracies and feel free to add elaborate or correct me if you see anything wrong.\nThis is a very complicated topic we still don't understand fully in humans but we do understand that for at least some characteristics it has to do with Barr bodies and epigenetic inheritance, no... |
[
"What's the deal with Bell's Paulsy - how does it occur and what's actually happening? Why would it happen to a 10 year old?"
] | [
false
] | null | [
"You can find basic info with a simple Google search which will lead you to the NINDS website... Do you have a more specific question? "
] | [
"I mean sure... How does it occur ",
"? All I can find is \"damage or trauma to the facial nerves,\" but where would that damage or trauma come from? And again, why would it occur with a child? I had it when I was 10 and was told it's extremely rare in kids.",
"I might just be dumb, but ELI5 don't allow these s... | [
"There are sections on this on the wiki for Bell's Palsy. Causes unknown. Could be inflammation of a facial nerve caused initially by a viral infection although there are lots of other possible causes and risk factors. As to why you in particular had it as a kid isn't something that can be answered."
] |
[
"How are eggs shaped so perfectly?"
] | [
false
] | If what I have read is correct, forming the egg shell is the last step. How is the shell formed around a soft egg without various deformations, and with nearly perfectly circular cross sections? | [
"I actually have chickens, their eggs are all shapes and sizes.\n",
"Example",
"\nThe ones you see in the store have been picked from all the colorful ones and all the \"misshapen\" ones so that they all look the same color, size, and shape."
] | [
"Exactly, the reason they're all the same shape is they only sell you the ones that are the \"right\" shape."
] | [
"The eggs you will buy in a store will all roughly be same shape, like w3rthlessspe0n said. But if you ever get the chance to raise chickens (or buy farm fresh eggs) you will see more interesting shapes. They range in both shape and size, and once my father found an egg no bigger than a gumball and perfectly round ... |
[
"If salmon return to the same river every year, why are there salmon in more than one river?"
] | [
false
] | Did they just get lost? Did humans move salmon eggs around? Did separate river ecosystems all evolve to have the same species? | [
"I think it would be similar to how insects and birds that are on the mainland can also be found on islands - a small number of fish get lost and manage to find another river to breed in. If separate rivers evolved separately, they would be different species (though they may still be able to interbreed). "
] | [
"I don't know the answer to this. I live and work on the east coast (no salmon) but as a fish ecologist, I have a few good ideas.",
"The most reasonable to me is that not ",
" salmon return to the same river. In any population, there are going to be some strange individuals who are not exactly like their pare... | [
"just looked it up, someone said they could do DNA testing insted of physical tagging, i couldnt find any evidence of someone doing it though"
] |
[
"What kind of success did alchemy have?"
] | [
false
] | You always hear about the outlandish failures of alchemy: it failed to turn lead into gold, failed to make people immortal, failed to create the fabled fifth element (æther). But what success did alchemy have? Since so may people believed and practiced it for so many hundred years I'd assume it made some progress or had some experimental successes it could show off. Am I right? If so, what kind of successes did they have? [Added a "chemistry"-flare since it forced me to add one, when this question is more for the historians of science.] | [
"One of the kings of the German kingdom of Saxony, Augustus the Strong, hired an (al)chemist call Böttger to invent a method of making gold - he failed entirely, but in the process came up with a technique of making high quality porcelain, which started large scale production in Meissen in 1710. Until then, porcela... | [
"The chemistry flair works quite well, actually, since \"alchemy\" and \"chemistry\" are basically the same word. The \"al\" of \"alchemy\" is just the Arabic word for \"the\". I forget offhand what the original Arabic origin of \"chemy\" meant, but you can see the relation to \"chemistry\".",
"From a 21st centur... | [
"This is exactly the kind of thing I was looking for. Thank you very much! If you have more examples please share!"
] |
[
"What's the difference between carbonite and carbon dioxide? They both have the same formula . . ."
] | [
false
] | [deleted] | [
"Carbon dioxide is a neutral species. On the other hand, carbonite is a double charged ion, which can be written as [CO2]",
". In other words, if you find a way to remove the two excess electrons from carbonite you can get carbon dioxide. "
] | [
"That's the carbonate anion. The -ite and -ate denote different chemical formulas."
] | [
"Lithium is able to form a carbonite, but only under extreme cold (15 Kelvin). (wikipedia)"
] |
[
"How nutritious are animal organs (besides skeletal muscle)? Should we be eating some of them?"
] | [
false
] | I understand not eating brains (mad cow disease) and intestines (poop). But what about things like livers, kidneys, bone marrow? | [
"People eat a lot of offal meat. Prior to supermarkets and pre-packaged meat, it was very common to eat pretty much every part of an animal.",
"Liver",
" is not only tasty, but incredibly high in iron and a bunch of other vitamins/minerals. Have you ever heard the expression, \"what am I? Chopped liver?\"? This... | [
"Years ago, PBS aired an installment of the NOVA series called ",
"Becoming Human",
" where the opinion of anthropologists studying human origins was put forth that our early ancestor's ability to use tools allowed us to scavenge the carcasses of animals killed by other top predators and extract bone marrow tha... | [
"I know in some cultures the gallbladder and other organs of certain snakes are eaten or used as medicine. Is there any scientific backing to this? My gut tells me no, and a google search turns up a myriad of results."
] |
[
"Since we now have superconductors that exist well over the boiling point of liquid nitrogen, why haven't we built super excellent power storage facilities with them?"
] | [
false
] | null | [
"Because a superconductor will wind up storing any power that you put into it in the form of a magnetic field. One of the fundamental properties that separates a superconductor from a \"perfect\" classical conductor (just a metal with infinite conductivity) is that a superconductor will expel magnetic field lines f... | [
"Thanks for the informative reply. I found more info about a couple of SMES installations. It sounds like these are used more as backup power during large transients. "
] | [
"Doesn't the Meissner effect only apply for a certain superconducters? There's a distinction between type 1 and type 2 which relates to their expulsion of magnetic fields."
] |
[
"Is it possible for a large celestial body to collide with another at low speed?"
] | [
false
] | For example if something the size of the moon were trailing the earth but at a only slightly faster speed. I'm going to assume the earths gravity would increase the velocity of the object, but I'm wondering if it would need to be a planet obliterating event without the high relative speeds? | [
"If the bodies collide, or even just come close, at slow relative speed, then their gravity certainly cause them to properly collide and the effects will be devastating for both. Even if you magically place the two so that their surfaces just touch at zero relative speed, they will very quickly merge and become a s... | [
"Hmmm that makes a lot of sense. ",
"There goes my science fiction vision of a double planet. "
] | [
"Hmmm that makes a lot of sense. ",
"There goes my science fiction vision of a double planet. "
] |
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