title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Vacuum pull to Space"
] | [
false
] | Imagine a tube, located on land, from sea level to low earth orbit or just short of it. Would it be possible for the vacuum of space to suction up the contents of the tube? Would it be possible to construct a tube capable of sustaining that type of suction down to the base of the tube without collapsing, giving us the ability to use the vacuum of space as a force to exit the planet? I don't know how to begin estimating calculations to think this could be structurally possible. This could be a very efficient way to launch people into space towards space stations and even used as a phase one launch to other celestial bodies. I just thought it sounded cool and was looking for other input about it. | [
"The point thetripp was trying to make was that the atmosphere is also 'open' to space.",
"Vacuum does not actually suck. The pressure in the pressurized part presses. And in the direction of space, it does press. But gravity pulls in the other direction.",
"This would be just as true in your straw. The gravity... | [
"This question gets asked a lot, and the answer is no - the vacuum of space cannot be used in the way you are thinking. To help you understand why, I would ask that you consider what, if anything, is different between the scenario you describe (a straw from the surface of earth to space) and the actual scenario of... | [
"Why doesn't all the air on Earth escape into space? What's holding it in, and would that also affect your tube?*",
"*Gravity, and yes."
] |
[
"How do biologists divide asexually reproducing organisms into species?"
] | [
false
] | I remember one working definition of "species" that went somethin like: Individuals who can produce fertile offspring belong to the same species. Of course this does not apply to organisms that reproduce asexually. How do biologists determine the borders among species for, say, bacteria? | [
"Poorly.",
"Taxonomy of procaryotes is messy and convoluted and is currently undergoing radical overhaul (and there are all sorts of competing ideas --all over the place in biology, but it's the most extreme in procaryotes-- and debates about how to better organize taxons). Over the past couple decades there hav... | [
"Excellent question.",
"Under the biological species concept (BSC), you really can't. This is because the BSC is biased towards sexually reproducing organisms.",
"A better definition of a species (to me) is the unified species concept (USC). Recall that populations evolve; to the USC, a species is defined as a ... | [
"You're quoting one species definition, the biological species concept. There are many different species concepts: John Wilkins described ",
"A list of 26 Species “Concepts”",
" and those aren't all-encompassing. ",
"More important, all of these are just definitions. That means they have ",
" to do with b... |
[
"Why is the Inflation Theory so important in understanding the Big Bang?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"/r/askscience",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"This is a common question covered in the ",
"AskScience FAQ",
"If ... | [
"Thank you for the message, ",
"I've actually been doing that for the last couple of days. I'll research more then.",
"Have a great day, ",
"-MAD623"
] | [
"AskScience has a bunch of past threads on it, but the Wiki article",
"\n",
"https://en.wikipedia.org/wiki/Inflation_%28cosmology%29#Motivations",
"\nsums it nicely, without inflation you have, ",
"The horizon problem - why our universe in thermal equilibrium",
"The flatness problem - why our universe's ... |
[
"What would happen to me if I stood in the path of the Large Hadron Collider?"
] | [
false
] | null | [
"A similar thing ",
"happened to a Russian scientist in 1978.",
" The short of it is this guy survived even though he received a \"lethal dose\" of radiation because he got lucky where the beam struck. ",
"The LHC has far higher beam energies (~13 TeV max)* than this old synchrotron (~76 GeV max) and thus it ... | [
"Just thought I would add ",
"some pictures",
"."
] | [
"No, but it did pass through him, causing damage along the way. "
] |
[
"If R=V/I, how come power lines have such low resistance?"
] | [
false
] | [deleted] | [
"The quantity you care about is the ",
" dissipated as heat in the wire. It turns out that the resistive power loss is equal to ",
"P_l = I",
" * R",
"Now the power transmitted over the wire is equal simply to ",
"P = I * V",
"So by increasing the voltage and decreasing the current, the transmitted pow... | [
"Well, remember, resistance is more a property of the material than what you do to the material (except heating it). It's a measure of how much current will flow across the material given some potential difference, I=V/R.",
"Anyway, in a power line, it's not that it changes the ",
" of the line, it's that it ch... | [
"You aren't understanding the circuit well if this is your question.",
"V is the power drop ",
". In this case, the single wire is the resistive element. The resistance in the wire is very small. However, the voltage drop between the ",
" (the +ve and the -ve, to use the DC terminology) of the electrical grid... |
[
"Why are musical notes in an octave?"
] | [
false
] | Is there any reason behind them being their specific frequencies or is it just a system that we invented long ago that still pretty much works? | [
"Let's say you have two notes, f1 and f2 (f is for frequency).",
"When f1 = 2*f2, they are one octave apart. If you have an instrument like a violin, playing an open string then stopping it at the midway point (half the string length = double the frequency) will result in the second note being an octave up.",
"... | [
"Octaves themselves exist since doubled/halved frequencies are perceived as the same note, just higher or lower, respectively. The divisions of an octave into other notes that comprise it is mostly arbitrary - there are in fact alternative systems, e.g. dividing an octave into 15 semitones rather than 12."
] | [
"Got a good source about mathematics of music? I'm a physicist who would like to learn all about this stuff during my free time."
] |
[
"Why doesn’t light bounce against cladding in single mode optical fibre?"
] | [
false
] | I can’t seem to find anything explaining how light waves can possibly travel straight through the middle without bouncing inside an optical fibre and I really wan’t to know how it works. | [
"Basically the core in single mode fiber (SMF) is so narrow that you can no longer accurately model it with ray optics. You need to consider the full electromagnetic wave equation to understand how SMF works. ",
"You can see a similar effect when a water wave moves in a narrow canal, ",
"for example, here",
"... | [
"If you look at the electric field pattern, it does touch the sides, and even extends into the cladding a bit. It just touches it equally all around, rather than sometimes one side and other times the other side like a ray optics model might make you expect."
] | [
"Have you ever seen a mirage on a hot road? That is a reflection due to a difference in refractive index between warmer(lower index) and cooler(higher index) air. The reflection only happens when the light hits the boundary at a shallow angle. There is a difference in refractive index between the core(higher index)... |
[
"How does one photon have more / less energy than another photon ?"
] | [
false
] | null | [
"Their energy is proportional to their frequency. It is kinetic energy, of course the Newtonian expression for kinetic energy won’t work because something travelling at the speed of light is as far from the Newtonian regime as possible"
] | [
"Why can any given thing have energy and have it in different amounts, and why do you think photons don’t meet this criteria? I might be able to better answer if you can talk a bit around the question"
] | [
"That’s ok. That’s helpful in formulating a hopefully useful answer, so thank you.",
"So the problem is that the wave-particle duality thing is a little misleading. Photons (or any “particle”) aren’t either waves or particles nor are they both. Photons in particular are specific configurations of the electromagne... |
[
"Has the string theory been validated by any experimental evidence like from the LHC?"
] | [
false
] | Are there better contenders for the theory of everything? I know just the basics of what the string theory is, that is using vibrating strings and extra dimensions to explain all the different forces and particles. I come from a medical background, so please excuse any gross misunderstandings of the concept. | [
"Some required aspects of string theory have been constrained by the LHC. ",
"String theory requires more than the 4 dimensions of space time. The size of the proposed dimensions has been constrained as if they were larger we would have seen things that disagreed with the standard model.",
"Super String Theor... | [
"No, I may have worded it badly. Models that are within Super String Theory made incorrect predictions about low energy super symmetry. Those models have failed, not string theory itself. Super String Theory in general does not make any generic predictions about \"low energy\" physics, so there is no current pre... | [
"The biggest factor is that we don't see more than 4 spacetime dimensions. This means they have to be hidden someway. There are so many of these you can get almost any low-energy physics you want."
] |
[
"Why can't our eyes move smoothly as we scan across our field of view, but can move smoothly when focusing and tracking a moving object across our field of view?"
] | [
false
] | Try this experiment: film your face with your phone as you look to the side and try to move your eyes smoothly across the screen. You can't. All you'll see is eye movement (rapid little darts in eye position). Next, hold your finger behind your phone and focus on it while you move your finger from one side to the other. You'll see that your eyes move perfectly smooth while they track your finger. Why is this the case? I can already imagine evolutionary motivations for it: when we look out into our environment, we are performing so rapid, darting eye movements are good for snapping from one area of interest to another. But, when tracking a moving object of interest (such as prey) it is important to be able to smoothly fixate on it. But my question is, do we know the involve in this? Is there some sort of reflex involved? | [
"When you fixate on a target you do what’s called a pursuit eye movement as you track it. These are smooth almost involuntarily extra ocular muscle movements to maintain binocular fixation of the retinal image on the fovea (area with the most dense photo receptors)\nWhen you try to voluntarily do the same thing you... | [
"This makes a lot of sense, thank you!"
] | [
"This comes from the input from a combination of cranial nerves and is called the vestibulo ocular reflex.",
"My favourite fact about that is that it's controlled by just three neurons."
] |
[
"How do we decide where a mountain begins?"
] | [
false
] | At what point are you “on the mountain” as opposed to being on the countryside around a mountain, or on a neighbouring mountain? I’m curious if there’s a specific point where someone would be considered standing on the mountain as opposed to under/beside the mountain or on the next mountain. Edit: my question was spurned by this post about the “base” of Olympus Mons on Mars: | [
"Speaking as a geologist. ",
"As with everything in science one needs to define terms. 'A mountain is...According to this particular definition it's starts...' ",
"An aside, nobody gets that caught up what a mountain is. It has a bit of relevance in volcanology but otherwise not too much. More relevant is the... | [
"Thanks for that, mate. Always appreciate hearing info from someone in specific fields. :)"
] | [
"Not a geographer but my guess would be you would take the average elevation difference of the surrounding terrain and draw the line where the elevation shift is not lining up with the differential average(ex: when the terrain starts to really become mountain instead of just a hilly patch of land)"
] |
[
"Does pollination between different plant species occur? If so, does it cause issues in the gene pool?"
] | [
false
] | null | [
"While this is the norm, its not at all the full story.",
"Very often, the hybrid plant is more fit than either parent species. This is known as hybrid vigor and, while it can happen in animals its far more common in plants.",
"Hybrid sterility can still be a problem but , plants have a trick for this called wh... | [
"While this is the norm, its not at all the full story.",
"Very often, the hybrid plant is more fit than either parent species. This is known as hybrid vigor and, while it can happen in animals its far more common in plants.",
"Hybrid sterility can still be a problem but , plants have a trick for this called wh... | [
"While I imagine you're actually referring to fertilization, it's worth pointing out that pollination only means that some pollen is deposited on the surface of the stigma. Pollen from another species can end up on a flower's stigma really easily, especially in plants that are pollinated by generalist pollinators o... |
[
"Vaccine study (including thimerosol) with rhesus macaque infants showed significant neurological changes. Does it have ANY relevance to humans in 2012?"
] | [
false
] | In , researchers tested the effects of 90s-style vaccines (includes thimerosal) on rhesus macaque infants. Neuroimaging detected significant differences in the vaccinated group versus the control group. From the Discussion: "Volumetric analyses identified significantly greater total brain volume in exposed compared with unexposed animals at both measured time points." And then... "Interestingly, a rapid increase in total brain volume between 6 and 14 months is generally considered to be a consistent finding for many children with an Autism Spectrum Disorder" Of course, since thimerosal is no longer in use, the information in this study already seems pretty irrelevant to whether you would have a kid vaccinated in 2012. HOWEVER, when you have crazy relatives that say things like, "well if they'd put this drug in a vaccine without knowing how harmful it is, who knows what kinds of other harmful things could be in it now?" Then you need a little more ammo to fire back with. So, in the opinion of askscience, is this study legit, and does it have any relevance to humans in 2012? By the way, if I am posting this in the wrong place, please tell me so that I can correct my mistake. Thank you! | [
"It's part of the monkey studies led by several researchers who have performed some rather shoddy studies in the past. ",
"It's an interesting story"
] | [
"I'm not a neurologist, but reading through the study I find it very difficult to believe the results imply much about the effects of thimerosol on humans.",
"They did a very small study of only 16 macaque monkeys split into two groups. Any statistical difference among such a tiny group had to be a very large ch... | [
"Holy cow, that definitely puts the study into perspective. I had no idea. Thanks for the history lesson."
] |
[
"Why is brain-to-body size often used as an indicator of intelligence (looking at you, koalas) instead of raw brain size?"
] | [
false
] | Wouldn't animals with similar brain sizes be similarly intelligent irrespective of body size? In other words, does a bigger body require a bigger brain for the same functionality? | [
"Because a large portion of the brain is used to control the body, homeostasis and similar thing, so you can't expect a large animal with an extremelly small brain to be able to both conduct all of it's bodilly functions and have a high intelligence. All functions in the brain need some space, because neurons have ... | [
"It does contribute by transmitting the signal to the muscles (the neurons that connect to the muscle are different), and controlling involuntary actions - partially visceral actions in specific nuclei, but a lot of information for them is also sent from above, and controlling reflexes. And mammals do have a well d... | [
"It s probably more of a rough correlation of observations with one variable beeing very empiric: what is intelligence ?\nA good part of the brain in human mammals is used to process vision, in dogs would be smell etc..."
] |
[
"For as long as I can remember I have had frequent episodes of lucid dreaming, sleep paralysis, and what an online search called \"hypnopompic hallucinations.\" Is this combination or frequency special enough that I should be volunteering for sleep studies?"
] | [
false
] | null | [
"This falls under our rule against giving ",
"medical advice",
". If you have medical questions please go ask them to a medical professional."
] | [
"I am not asking for medical advice. From my perspective this is not a problem, medical or otherwise. I adjusted to this before I was even a teenager and very much enjoy lucid dreaming. ",
"I am asking strictly for research purposes. I thought maybe there was a neuroscientist out there that was interested in s... | [
"This still falls under the medical advice rules within ",
"/r/askscience",
". You are asking about a particular medical condition concerning yourself.",
"If you don't agree with that you can try reaching for higher level mods through the modmail (link in the sidebar). ",
"I advise you to try other subreddi... |
[
"Can you lose part of your brain with no noticeable difference to your personality or brain functionality?"
] | [
false
] | [deleted] | [
"well, your concious may not notcie it because i lost the ability to notice it",
"it is possible of course, there have been cases were peoples brains received a bullet",
"but it turned them into monsters for the rest of their lifes",
"i had a tbi as a kid was knocked out at least 5 to 10 minutes",
"amtough ... | [
"the brain is incredibly resilient and adaptable, altough complex and fragile",
"litterally anything could happen"
] | [
"the brain is incredibly resilient and adaptable, altough complex and fragile",
"litterally anything could happen"
] |
[
"Do any viruses other than Chickenpox reemerge after the primary infection and cause a second disease like the varicella-zoster virus causes Shingles?"
] | [
false
] | I know that Shingles is a reactivation of the virus that causes Chickenpox, and if you haven't had Chickenpox, you can't get Shingles (although you can get Chickenpox from someone who has Shingles). Are there any other viruses that lay dormant and cause a future infection? Is SARS-CoV-2 a type that could reactivate later? | [
"HIV causes an acute disease of flu-like symptoms when you first get infected. Then it goes dormant, sometimes for years. And then, slowly slowly, it erodes away your immune system, until you start getting chronically sick with opportunistic infections."
] | [
"In addition to herpesviruses which ",
"/u/vbwrg",
" mentioned, some polyomaviruses can reactivate if the immune system is weakened. These include things like ",
"BK virus",
" and ",
"JC virus",
" which can cause severe disease (brain damage, kidney damage, etc.) in transplant recipients taking immunosu... | [
"The only viruses that can go dormant and reactivate later are those capable of causing chronic infections. Herpesviruses like the varicella-zoster virus that causes chickenpox and shingles are the masters of this. All herpesviruses are capable of latency and later reactivation, including the herpes simplex virus... |
[
"Why does it take so long for common CFL bulbs to achieve full brightness?"
] | [
false
] | I've noticed for years that compact fluorescent light bulbs will turn on quickly, but their brightness will continue to increase a little over the course of the next few minutes. I am curious about the electrical/chemical/other mechanisms behind that lagging intensity. | [
"AFAIK, Flourescent bulbs function sub-optimally at colder temperatures. Once the bulb reaches an optimal temperature, they achieve full brightness.",
"Source: I work for an electrical distributor as an events manager and attended the same Lighting seminar 6 times."
] | [
"Cool. Helpful! "
] | [
"To add to this, why do they have paler light?"
] |
[
"Perhaps a silly question; why is space so cold?"
] | [
false
] | null | [
"Temperature is a measure of the average kinetic energy of the particles in your medium. In a vacuum, there are ",
" few particles (atoms, molecules, etc) present, and although those that are present may have a great deal of energy, there simply aren't enough for the word \"temperature\" to have much meaning.",
... | [
"Loss of heat by radiation is hilariously slow and inefficient."
] | [
"I was bored, so here's a solution to the differential equation that would describe the temperature of a iron ball with a radius of 1m, cooling only through black-body radiation starting at 533 Kelvin. This is a plot of the first seven days.",
"http://www.wolframalpha.com/input/?i=Plot[%28%28533%29+^%28-3%29+%2B... |
[
"Looking at WWI/II fighter aircrafts, isn't it dangerous having the aircraft's propellers within the machine gun's line of fire?"
] | [
false
] | null | [
"Yes, it would be, and manufacturers came up with different solutions to this. Some mounted the guns completely above the propeller, others ",
"synchronized the firing rate to the propeller's rotation."
] | [
"Thank you, I came to the thread to say this.",
"The synchronized machine gun was at the time a great feat of technology. These days synchronizing a mechanism even lower than .1 second is easy peasy. A couple 3 volt relays and a $.25 controller chip. ",
"But in 1916 tensioning a chain without slippage to tho... | [
"And in the first world war, there was at least one aircraft where the gun barrel went through the center of the rotary engine (not to be confused with a radial engine)."
] |
[
"What does it mean for worker bees to be \"female\"?"
] | [
false
] | Worker bees are "designed" in a way it is absolutely not possible for them to bear children. In fact they lack necessary organs, for example their egg laying apparatus was modified in a way that it now functions as a stinger. They don't produce eggs and are not able to do so. This seems to me to be in odds with the very definition of being a female. For example according to Wikipedia "female (♀) is the sex of an organism, or a part of an organism, which produces non-mobile ova (egg cells)", and Webster defines is as "of or relating to the sex that can produce young or lay eggs". Obviously this may not be true on an level - there exist individuals belonging to the sex, who (for one reason or another) are born sterile or are rendered sterile later in life. We obviously still consider them female. However, the case of worker bees seems to be quantitatively different. They seem to be a separate of an individual, and their sterility is certainly not a fluke on an individual level. Most sexually reproducing species have two basic of individuals - those that produce eggs (females) and those that fertilize them (males). Worker bees doesn't seem to belong to either one of them. So my question is: I suspect the answer may be: they share chromosomal layout with fertile females of their species, but not fertile males. Also, they had potential to become fertile females during initial development, depending on environmental variables. This answer would be only partially satisfying. There are many species with no difference between sexes on a genetic level. There are many species where sex is determined based on an environment, and even species whose members can change sex later in their lives. We still consider those individuals male or female purely based on a they fulfill. So I suspect there is a better answer when it comes to worker bees than the one I was able to come up with. | [
"I had never heard about \"laying worker bees\" but ",
"here's a wiki:",
"Even in a normal hive, about 1% of workers have ovaries developed enough to lay eggs. However the usual number of the laid eggs is very small. Only eight eggs (seven moderately and one fully developed) were found after examining of 10,634... | [
"They are female, because even the workers can lay eggs, but just male eggs, because the sperm is missing.\nEvery female bee is the same (So every worker is a queen), the workers are just \"castrated\" throught the queens pheromones and the diet in the larva-stadium."
] | [
"But they can built them up and lay eggs -male eggs, if the Queen dies, then they will... not all -because if likely 5 start, the others think there would be a queen, but ..they will .)",
"Just for the ressource, I'm a beekeeper for 4 years now.",
"So it just needs time, but normally every female bee could lay ... |
[
"Why does human brain tissue start to die after only 4-6 minutes without oxygen when other body tissues can survive for hours without oxygen?"
] | [
false
] | Are there any other mammals with brains that can survive longer without oxygen? If so, why? | [
"Briefly, one of the reasons is that the glycolytic capacity of the brain is low. Consequentially, ATP depletion and lactate production is dramatic in the brain.",
"This paper",
" should answer your question quite comprehensively. If you can't access it, send me a PM and we'll get you the pdf."
] | [
"If you don't really want to wade through the paper that was posted, the tl;dr of it is that neurons, in particular, rely heavily on maintaining ionic homeostasis across the cell membrane, and this is mostly upheld by the Na+/K+ exchange pump, an ATPase (meaning it cleaves ATP to provide the energy to undergo what ... | [
"I think that it does. When you are not moving, your muscles use very little oxygen. There isn't really an analogous state for the brain. Additionally, if you kill some muscle cells, they will grow back. Your brain will not. ergo, you notice it more.",
"I suppose the other part of the question is \"can other ma... |
[
"I tried boiling water in the microwave and it didn't work, until I took it out and it spontaneously erupted for 5 seconds and stopped as suddenly as it started. Why?"
] | [
false
] | It wasn't even when I set it on the counter. I was making jello and getting frustrated that the water wouldn't boil. I decided it was hot enough and took it out. After sitting on the counter for a few seconds it exploded bubbling boiling water all over the counter. Then it stopped boiling completely. This at least makes sense since it shot all its energy out. But how did it store that heat without boiling??? Was my Pyrex measuring cup too smooth and boiling requires a point for the bubble to form? Setting it on the counter disturbed it and suddenly the water realized it was well past its boiling point? There was no lid involved and it was regular tap water. | [
"Your guess was right. Pyrex is very smooth. If there are no irregularities, it's possible that no bubbles form. The water just basically becomes superheated. Once it's disturbed, causing irregularity, it'll boil in a flash. When I microwave water in Pyrex, I always put a wooden skewer in there to give the bubbles ... | [
"At least there is a scientific answer. I can see someone thinking this was straight up magic. "
] | [
"Yeah, put a wooden toothpick in water you are heating in the microwave to create nucleation sites. Superheating can burn the crap out of your hand."
] |
[
"If you to stand at the base of a space elevator, and look up on a clear and cloudless day (or night), would you be able to see the counterweight on its end?"
] | [
false
] | The counterweight would have to be above an altitude of 35,800 km (22245.1 miles... which, to help visualize that length, is 89.33% of the circumference of the earth). Obviously, this would depend on how big the counterweight is. As such, perhaps a more precise (and therefore perhaps more answerable) question would be this: what size would the counterweight have to be, so as to be visible from the base of a space elevator? And what about for someone like me, with 20/10 vision, what size would it then have to be? EDIT: Not sure of the right flair for this. I went with Biology, because it's about a person's eyes. However, I think perhaps physics would be applicable, too. | [
"If that's the case, then how are stars visible? or the ISS? Or the Moon?"
] | [
"Humans can resolve things at an angular resolution of .07 degrees",
" That means to see something 35800 km away, it'd need to have a diameter of about 44km. "
] | [
"For what size object? We can see the moon quite clearly (granted, that object is huge), and it's far further than 100 miles. ",
"Therefore, there must be some size at which an object is visible at the distance of the counterweight. What size would the counterweight need to be, to be seen from that distance?"
] |
[
"Are there flying insects out in the middle of the Pacific Ocean?"
] | [
false
] | Say you're on a boat in the middle of the Pacific, miles from any island. Would there be anything like flying above water, like gnats or smaller? | [
"Insects aren't noted for being marine (relatively few species live in or near saltwater), but they've been dispersed to many Pacific islands (the Hawaiian islands being some of the most remote landmasses). Air and water currents are frequently invoked as colonization mechanisms. So while you might find some flie... | [
"i go fishing off the coast of mexico all the time and ive seen butterflies as far as 5 miles out flying around pretty regularly. i think they just get lost and fly as far as they can until exhaustion. strong winds probably play a big role as well."
] | [
"Some, at least:",
"Every year, millions of dragonflies fly thousands of kilometres across the sea from southern India to Africa.",
"http://news.bbc.co.uk/earth/hi/earth_news/newsid_8149000/8149714.stm",
"That article also discusses butterflies."
] |
[
"Are there any negative environmental impacts from collecting and using solar and wind energy?"
] | [
false
] | null | [
"Lots of drawbacks to both solar and wind. As a couple of people have mentioned wind power can be pretty disastrous for birds and bats. ",
"Altamont Pass",
" is well known for slaughtering birds of prey. Though keep in mind that Altamont Pass is pretty old in both design and placement. The problem is basical... | [
"This ",
"article",
" might be of some interest."
] | [
"That is an interesting article, I didn't know bats were such an important aspect when it comes to pest control. "
] |
[
"How are scientists able to determine which chemicals in the brain correspond to certain emotions and actions?"
] | [
false
] | [deleted] | [
"First of all, the human brain is extremely, insanely, absurdly, complex. Almost anything you read in the popular press about the links between neurotransmitters and behaviours is undoubtedly simplified, ",
" if it's about \"higher-order\" cognitive processes like emotions, beliefs, etc.",
"That being said, th... | [
"Excellent reply! Another (very common) way to study the role of different brain chemicals in behavior is to inject those chemicals into an animal's brain. Scientists inject neurotransmitter analogs, or the neurotransmitter itself, into the brain. We can also inject drugs that block the activity of certain neurotra... | [
"Also, the studying a person who has a sustained a certain injury to a select part of the brain offers a slightly more ethical way of understanding what areas of the brain are involved in what behaviours or function."
] |
[
"How does the velocity of planets affect the time dilation for objects on it?"
] | [
false
] | [deleted] | [
"Technically the speed of the planet ",
" have an effect on the time dilation but it would be relatively tiny; planets and stars move too slowly to notice the effects of Special Relativity (i.e. time dilation due to speed) or such effects are vastly outshined by those of General Relativity (i.e. time dilation due... | [
"Yes, slightly. Time dilation actually effects the precision of GPS satellites and must be corrected for."
] | [
"Satellites are affected in two ways.",
"There is a special relativistic time dilation due to their speed relative to an observer on the ground. That is, to an observer on the ground, the clock of the satellite appears to run slow.",
"There is also a general relativistic time dilation due to the satellite being... |
[
"A quick question about relativity"
] | [
false
] | I was reading about how when you reach the speed of light, time essentially stops. Wouldn't this mean that light is actually moving than the assumed speed limit? IIRC it takes light from the sun 8 minutes to reach earth, if at this speed time stopped, then the trip would be instant from our perspective. It would make sense if light was actually moving slightly slower than this "speed limit" but not at the absolute maximum. Since i'm pretty sure i'm just not properly understanding something, can anyone explain it to me a little better? | [
"The whole basis of relativity is that there is no measurement in an inertial frame that will measure light in a vacuum at any other speed."
] | [
"Also remember that when talking about this nonsensical photon reference frame, not only is it experiencing no time, but it's traveling no distance as well."
] | [
"Ok, first, the whole idea about time stopping at speed of light is bollocks. You cannot reach the speed of light. While time does slow down relative to others as you speed up towards the speed of light, it never stops.",
"Only energy / massless particles move at the speed of light, and they cannot \"experience\"... |
[
"can any solids melt in a vacuum?"
] | [
false
] | (Specifically an ultra hard vacuum like in interstellar space.) I've seen answers to the related question, "Can any liquids *exist* in a vacuum?", to which the answer seems to be "From a practical standpoint, yes, from a technical standpoint no." All liquids have some finite vapor pressure, so in a perfect vacuum they won't technically be stable and will continue evaporating, but if their vapor pressure is low enough then this will happen very slowly, and they can remain liquid for timescales of years or more. Apparently some 'ionic liquids' are quite good for this, with vapor pressures so small they often can't be measured. My question, however, is about the phase change itself. Could you start with a frozen solid sample of a low vapor pressure liquid, and then heat it up in a vacuum until it melts into a liquid? Or in that case would it go directly from solid to liquid? | [
"There are definitely at least ",
" solids that will happily melt in a vacuum. Let's agree that we only count it as \"melting\" if the amount of liquid is macroscopic and lasts for at least a few minutes.",
"Even so, probably most ionic liquids, and other low-vapor-pressure liquids like glycerol, will work, but... | [
"I think this question has already been answered on another reddit post from aways back:",
"",
"https://www.reddit.com/r/askscience/comments/1km5qg/can_a_strong_enough_vacuum_convert_a_solid_to_a/"
] | [
"The sticking point here is fundamentally just about vapor pressure. A true vacuum provides almost no stabilising vapor pressure, so traditional liquids are a no-go.",
"However;",
"Could you start with a frozen solid sample of a low vapor pressure liquid, and then heat it up in a vacuum until it melts into a li... |
[
"If chimps were to be breeded selectively based on their intelligence, how many generations would it take before we could describe them as \"human-like\" in terms of intelligence?"
] | [
false
] | null | [
"It wouldn't work that way. Even if there were selectively bred for intelligence there are simply too many differences between the human and chimpanzee brain for them to reach the potential of being \"human-like.\" Additionally, if you look at the ratio of brain mass to body size, chimpanzees have a much smaller ... | [
"Evolution has a couple genetic tools at its disposal...genetic potential, and mutation.",
"Genetic potential works with genes already in the gene pool...you breed big dogs together until all the \"big\" genes are all in one place, and you wind up with a Great Dane. This can happen within a few dozen generations... | [
"Slowly but certain pegasus_527 gazed upon his username"
] |
[
"Why are food allergies on the rise?"
] | [
false
] | null | [
"There are several theories on this out there right now, but none of these have been proven. It is important to realize that what your body is doing with an allergic reaction is similar to an immune response run amok.",
"The first one is that the types of foods we are exposed to right now is much broader than it ... | [
"Thanks for this detailed response. Interesting to think that our bodies are always looking for something to fight and that might be it. "
] | [
"So could you develop an allergy if you stop eating something for awhile? I started to eliminate grains from my diet. Once in a while I'll have grains, bread or wheat - and I'd feel lethargic. "
] |
[
"If speed can only be measured relatively, then is it correct to say the moon on the horizon orbits my head faster than the speed of light whenever I spin in a circle?"
] | [
false
] | [deleted] | [
"An inertial reference frame is one in which you don't accelerate, a non inertial reference frame is one where you do. Speed is relative when you're travelling at a constant velocity (speed and direction). If you and I pass each other at a constant speed neither of us can say that I'm moving and you're standing sti... | [
"An inertial reference frame is one in which you don't accelerate, a non inertial reference frame is one where you do. Speed is relative when you're travelling at a constant velocity (speed and direction). If you and I pass each other at a constant speed neither of us can say that I'm moving and you're standing sti... | [
"inertial reference frame so the same special relativity rules don't apply, we then apply general relativity.",
"Special relativity does handle acceleration, it just requires a more thoughtful and careful application.",
"\n",
"http://math.ucr.edu/home/baez/physics/Relativity/SR/acceleration.html"
] |
[
"How is the phenomenon of natural instinct passed on at a genetic level"
] | [
false
] | null | [
"Wish I could answer the OP's question, but I know that reflexes are a product of nerve stimulation that produces muscle contractions without the need for your brain to consciously react. In this case, it's passed on at a genetic level simply by the nature of how your nerves are connected to each other.",
"Sorry... | [
"Pretty much spot on. Reflexes are the result of (relatively) simple neuronal circuits that bypass higher cortical processing - which is why they are so quick. The most basic form like the Patellar reflex (",
"http://en.wikipedia.org/wiki/Patellar_reflex",
") can be pretty well explained by 'two neurons connect... | [
"I do hope you were referring to the edit. The idea of a meme refers to the spread of ",
" in populations, and that it undergoes \"selection\" like genes. While I'd be the first to argue that our development of culture is \"natural,\" this has ",
" NOTHING to do with how an instinct would be genetically provide... |
[
"Dental practices with Fluoride?"
] | [
false
] | So from what I've learned in school is that fluorine chemically "eats" calcium, and teeth are exactly that. So why is it that dentists would use fluoride gel or foam or what-have-you, on teeth? | [
"Here's a paper from the conspiracy nuts at the Harvard School of Public Health: ",
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491930/",
"\nThey try to evaluate the threshold at which negative effects from water fluoridation might be seen, and more or less end up suggesting that public water supplies should ... | [
"There are two key minerals in tooth enamel; hydroxlapatite and fluoroapetite. Fluoride treatment helps \"remineralize\" fluoroapatite which slows down cavity formation. "
] | [
"What do you mean 'fluorine eats calcium'? Calcium is an element, and fluorine certainly doesn't change that. Also, ",
" and ",
" refer to very different compounds."
] |
[
"How do scientists determine the origin of a pandemic so specifically?"
] | [
false
] | [deleted] | [
"Phylogenetic analysis you sequence the virus and measure how much they have evolved. So they had bat Coronavirus sequences since we found SARS in bats. Once you sequence an unknown virus you use similarity to other sequences to find similar things, generally using BLAST. Then you use phylogenetics to do a more spe... | [
"Basically identifying the RNA sequence of this virus and matching it against other known viruses that lve within these animal species.",
"All RNA has a code made of 4 building blocks, so whatever is the closest match is the most likely candidate."
] | [
"Usually diseases that are common enough to manage to mutate are common enough there is a ton of it around. Like it wouldn't be all bats, but the disease that mutates is really likely to be the super common version in the animal it came from. You need an awful lot of copies of a virus for one to happen to change s... |
[
"How can I visualize the propagation of an electromagnetic wave through 3D space?"
] | [
false
] | I've seen tons of diagrams of waves in textbooks, but they seem to always be from a "sideways" or "top" perspective - either propagating in circles from a central source or as a sin wave horizontally from their source. But what would a wave look like if, say, we could see 3D models of them? I ask because I was standing in my kitchen with a friend and, when she moved, she disturbed the radio reception. This got me thinking about these waves' physical manifestation and what they might look like if we could see them. I imagined her standing at either the peak or trough of one of the waves I've seen in textbooks. I understand that we can see light and that this might be a good analog for "seeing" micro, gamma or radio waves, but I'm more interested in understanding how accurate (or inaccurate) the diagrams we see in highschool and college intro courses textbooks are. | [
"An EM wave can take on many wave-front shapes, waveforms, and polarizations, so it takes a lot of practice to visualize EM waves in general. The simplest form to visualize is a vertically-polarized monochromatic plane wave. To a good a approximation, the waves created by a linear radio antenna pointing up are vert... | [
"would it be safe to visualize them as a sphere expanding from their origin?",
"Yes, if the radiation source is small compared to the distance to the observer, the source acts like a point source and therefore emits wavefronts that are expanding spheres (somewhat like the expanding ripples on a pond caused by thr... | [
"A wave in water isn't technically a physical thing; it's a perturbation of the water's surface that carries with it certain information like frequency and amplitude. Sounds waves are perturbations of the density of air. Electromagnetic waves (photons) are similarly perturbations of the EM field. It's been a long t... |
[
"Why are wind turbines the height they are?"
] | [
false
] | [deleted] | [
"Also as you have a longer blade, you are going to have more weight and stress on the joints. You are ultimately limited by the strength of the material. Nobody wants their blades snapping off. Same goes for the height. Too high and the torque from winds could blow it over. In this case, you could use tougher ... | [
"As the wind blows across the surface of the earth, something called a boundary layer is formed, and wind speed within the boundary layer is lower than outside of it. Depending on the terrain, that layer can be 100 meters or more thick, but it is usually less thick. Wind turbines need to get out of the boundary lay... | [
"Increasing the size of the blades also increases the weight and could make it take stronger winds to push the blades. They probably did a lot of studies on the aerodynamics of the blades to find the ideal blade size to try to maximize the efficiency. The height is also likely determined by a similar process to d... |
[
"What exactly causes the skin to itch?"
] | [
false
] | null | [
"unmyelinated tactile C fibers under your epidermis that are sensitive to mechanical stimuli and histamine."
] | [
"sorry. There are different types sensory nerve fibers in and under your skin that are in charge of letting you brain feel touch, heat, pain, itch...etc. The type that conveys itch are the slowest (type C) type of fibers, so you feel an itch a lot slower than say, when something touches you. ",
"The reason that ... | [
"I should maybe take this question to ",
"/r/explainlikeimfive"
] |
[
"Why are Saturn's rings nearly planar? Are all planetary rings planar for the same reason?"
] | [
false
] | null | [
"An interesting question, say you start with a moon (which is what saturn's rings started as) and you break it up into lots of pieces, either by a big collision or by tidal forces. These pieces will all be orbiting Saturn in a big thick ring made up of particles with some bulk motion (the same as the old moon had)... | [
"So the fact that it is planar suggests all of the inner rings were formed by one body? Are there any bodies with two intersecting ring formations?"
] | [
"We have 8 planets, 4 of them have rings, none of them have 2 intersecting sets of rings. As for a general rule, there is something stopping this. Remember that the two rings constantly orbit so the intersection point would have collisions between the two rings that would scatter the ring debris in pretty much any ... |
[
"What was the Amazon like when the Sahara was still green?"
] | [
false
] | The sandstorms from the Sahara are cited as a contributing factor to how big the Amazon is because of all the mineral nutrients that are carried in the sand to Amazon soil (and North American soil as well). Well what was the region like a few thousand years ago when those sandstorms weren't happening? Was it it's own dessert? Or did the Amazon river support a river plain like the Mississippi River basin in the US and Canada? | [
"I think you are misunderstanding what people mean when they say that nutrients are in short supply in Amazonian soils (or other rainforest soils, for that matter).",
"It is not that the rainforest happens to emerge in a nutrient poor region and needs an external inflow of nutrients in order to survive.",
"Rath... | [
"The \"Green Sahara\" has to be taken with a grain of salt. It was never a climax forest but has varied between extreme desert that it is today and open savannah grassland in different climate periods. The Amazon forest has also grown and shrunk. ",
"This diagram",
" shows some of the variations between both of... | [
"I am pretty sure if you took the 27 million tonnes of nutrients that come directly from the Sahara away, the rainforest would not survive. In fact, nutrients are in short supply in amazonian soils, thus the forest depends on the nutrients brought in by the wind to survive. NASA released an entire study on it: ",
... |
[
"Why does it take some people longer to achieve an orgasm?"
] | [
false
] | To elaborate, what are the differentiating factors (physical vs. mental) that determine how long it takes for a male or female to achieve an orgasms? Like, if there was a scientific formula, what would it look like? | [
"Premature ejaculation in men is thought to be related to increased number/increased firing of sensory/excitation cells on penis. One of experimental approaches for plastic surgeons to deal with that problem was to surgically scrape the shaft for some of them. I cant really quote you the success rate though.",
"O... | [
"Yeah, let's get down to the obvious practical things. There are so many little things:\nHow turned on are you?\nHow much lubricant?\nRhythm, pressure, position",
"Many medicines affect orgasm: Anticholinergics, antidepressants are very common. \nMedical conditions themselves also cause issues, whether it's decre... | [
"Yeah, let's get down to the obvious practical things. There are so many little things:\nHow turned on are you?\nHow much lubricant?\nRhythm, pressure, position",
"Many medicines affect orgasm: Anticholinergics, antidepressants are very common. \nMedical conditions themselves also cause issues, whether it's decre... |
[
"Does anyone have info about this infrared image, as seen on Google Sky?"
] | [
false
] | To the left, the large purple and black image that only appears in the infared view? | [
"I think the black is just indicating that that region of pixels is brighter than the dynamic range of the sensor."
] | [
"This is correct. The sensor is over saturated just as a digital camera would be in the visual spectrum if the sun was in the photo. The IR colorings are false so black in that photo equates to a heat that is at the peak or higher than the sensor can handle."
] | [
"I think what you are seeing is an effect known as blooming. The area of over saturated sensors is larger than the actual area emitting the offending heat. So sensors near the offending ones are also over saturated and thus you are missing what is in that transition area. This can happen both in the electronics as... |
[
"How do we get vitamin D from sunlight?"
] | [
false
] | There are no particles or molecules coming from the Sun, unless you take the photons into account. | [
"It's really pretty straightforward conceptually. Vitamin D is a breakdown product of cholesterol (basically, it's a modified cholesterol molecule with a couple of its carbon ring structures broken open). These changes happen to cholesterol molecules in the skin when they get exposed to sunlight, or, more specifica... | [
"I wanted to ask this question for a long time. ",
"Glass blocks UVB right? So If I'm driving my car with the windows up and the sun on me, there is no Vitamin D produced out of the UVA?"
] | [
"I wanted to ask this question for a long time. ",
"Glass blocks UVB right? So If I'm driving my car with the windows up and the sun on me, there is no Vitamin D produced out of the UVA?"
] |
[
"Why does neutron capture by nitrogen-14 in the atmosphere lead to carbon-14 instead of nitrogen-15?"
] | [
false
] | says "Carbon-14 is produced in the upper layers of the troposphere and the stratosphere by thermal neutrons absorbed by nitrogen atoms", the reaction being: n + N14 -> C14 + p. Why doesn't this produce N15? | [
"That’s not a capture reaction, it’s an (n,p) reaction (transfer or charge exchange). Neutron capture would be (n,γ). ",
"N(n,γ) would produce ",
"N.",
"Carbon-14 could be produced by the capture reaction ",
"C(n,γ)."
] | [
"In that notation, the thing after the comma is what comes ",
". \"14N(n,γ)15N\" means \"14N plus neutron in, 15N + gamma out. ",
"The actual reaction has a neutron coming in, proton going out. That means the mass stays the same, but the atomic number goes down by one due to the lost charge."
] | [
"(n,γ) means a neutron is captured and a gamma ray is emitted. You asked why ",
"N(n,p) “capture” doesn’t result in ",
"N. The answer is that (n,p) is not capture, and ",
"N(n,p) produces ",
"C, not ",
"N. In other words, “Why is a blue car not red?”. Because it’s blue."
] |
[
"Does a black hole grow as it absorbs more mass?"
] | [
false
] | null | [
"There is a direct correlation between the radius of a black hole's event horizon, and the amount of mass that is contained in the black hole. This is known as the ",
"Schwarzschild Radius",
". As it obtains more and more mass, the radius of the event horizon will continue to grow."
] | [
"yes, it means the black hole will not consume the universe anymoe than the star from which it originated. It will \"consume\" everything that collides with it though."
] | [
"No, because the universe is a very sparse place, tons of room between most objects, and is expanding. But they can get VERY big, like 10million times more massive than our Sun, usually in the centers of galaxies. [source: am a PhD Astronomer]"
] |
[
"If CO is called carbon monoxide to differentiate it from CO2, why isn't NO most commonly called nitrogen monoxide, rather than nitric oxide, to differentiate it from NO2?"
] | [
false
] | On that note, why is NO most commonly called oxide, rather than oxide? Why isn't NO2 called nitric dioxide instead? Are these all just the result of naming conventions, or do they serve a specific purpose? | [
"They are basically naming conventions. Endings like ",
" and ",
" give a clue to the oxidation state of the element in question -- the ",
" ending implies that the central atom is in the higher of two common oxidation states, while the ",
" ending implies that it is in the lower. ",
" and ",
" nomencla... | [
"The answer is slightly incorrect.",
"Nitrogen monoxide can ",
" refer to NO, as N2O would be referred to as dinitrogen monoxide. The mono- prefix is not explicitly stated for the leading element in these types of compounds. ",
"The explanation on the -ic and -ous endings is correct. This is also used in meta... | [
"I see. Thanks for your answer!"
] |
[
"Why does reception change with my TV antenna when I stand close to it?"
] | [
false
] | I thought maybe I was just imagining the difference in reception when I move around a room, or touch the antenna with my hand, but I think there really is some sore of effect there. Is my body conducting a signal or something? | [
"I don't think the body is a great antenna. It is conductive but has a lot of resistance compared to metals. The wavelength of the radio signal matches the physical length of an antenna rod, (or some multiple of the length). The radio wave resonates only with the matching element length, creating an electrical sign... | [
"Your body acts as an antenna. It's actually one of the best antennas available. "
] | [
"The antennas are designed to catch radiowaves at some wavelengths. In order to work correctly, they have different elements (conductor rods) that amplify, concentrate or bounce radiowaves, and a conductor that catches the radiowave and sends it to the TV through the cable. But you are made (mostly) of salty water,... |
[
"If humans could build an incredibly powerful telescope from earth and view galaxies, stars, and planets up close would you be seeing millions of years in the past?"
] | [
false
] | null | [
"Yes; light from 200 light years away left the source 200 years ago."
] | [
"Only inference. For example, we can now see the ",
"pillars of creation",
", but they may no longer be there because of a possible supernova that was closer to us that we can already detect."
] | [
"Thanks. So would there be no way of telling what it would be like in the present of the celestial mass?"
] |
[
"If you spun a helicopter rotor that was one-tenth the size, but spun ten times as fast, could you still achieve lift?"
] | [
false
] | null | [
"And that is how you clearly answer a question. Thank you."
] | [
"And that is how you clearly answer a question. Thank you."
] | [
"Wow that's amazing! Thank you! Really cleared a lot of things up. :)"
] |
[
"What is the loudest sound in the known universe?"
] | [
false
] | null | [
"Soundwaves require a medium to propagate, so we can't really \"hear\" interstellar objects.",
"The loudest sound recorded on Earth was \"The Bloop\"."
] | [
"I would actually argue that the August 27th 1883 eruption of Krackatoa was the loudest recorded (on paper) sound. ",
"It was so loud that even 3000(!) miles away, on the island of Rodrigues, people thought that there was nearby cannon fire. Loud to the point that even 5 days after the explosion air pressure mete... | [
"Saw ",
"this",
" on Reddit very recently and although there is no mention as to the auditory volume of the black hole's sound waves, the energy that created them is mind boggling and they are the lowest sound ever heard in nature. ",
"In musical terms, the pitch of the sound generated by the black hole trans... |
[
"If you could travel adjacent to a plane generating sonic booms at mach >= 1, would you hear a deafening roar that is a continuous sonic boom?"
] | [
false
] | null | [
"The shock wave that causes the sonic boom is very nearly a physical discontinuity in the air - it's only a few hundred nanometers in length. What we perceive as a sonic boom is the result of this extremely rapid change in pressure across the shock wave. If you are stationary relative to the shock wave, you will ... | [
"It would be like riding a jet ski right on top of a boat wave. That's what a sonic boom is. It's a \"splash\" in the air like a boat making in waves. The single boom you hear as a stationary view is just the wave hitting you and moving on "
] | [
"You wouldn't hear anything if your were next to the plane because you'd be traveling faster than or as fast as the the sound wave that trails the other plane. If you were a bit back say in the pressure wave wake of the plane, I suspect it would be very turbulent, deafening and more than a little dangerous."
] |
[
"Why aren't there uuu and ddd nucleons?"
] | [
false
] | [deleted] | [
"I will never achieve a level of education high enough to convince me that what you just said isn't gibberish"
] | [
"I will never achieve a level of education high enough to convince me that what you just said isn't gibberish"
] | [
"Ground state spin-1/2 uuu and ddd baryons are forbidden by the Pauli exclusion principle"
] |
[
"How does medicine cure depression?"
] | [
false
] | null | [
"Disclaimer, I'm on mobile so I won't include any sources. ",
"Depression is a really crazy disease that can have a lot of different symptoms. You can have deficits in cognition, motivation, motor activity, eating, sleeping, but then also the guilt, feelings of worthlessness, and on and on. This points to depress... | [
"The truth is, we don't really know. Some compounds are known to help through \"interactions\" with certain brain receptors, and that's about it. I say that in quote marks because the pharmacokinetics are not well understood. Some drugs seem to work for one person, but not for another. And for the people in which t... | [
"Please read this : ",
"https://www.theguardian.com/society/2019/jun/03/mental-illness-is-there-really-a-global-epidemic",
" ",
"and this : ",
"https://www.theguardian.com/science/2018/apr/26/gene-map-for-depression-sparks-hopes-of-new-generation-of-treatments"
] |
[
"Will occur refraction if there's a change in the overall luminosity?"
] | [
false
] | [deleted] | [
"Can you provide the link to the site? Is it a physical demonstration or just a description of something?"
] | [
"Here",
" is the link, completely in portuguese. ",
"It's a site focused on science fairs projects, some have a complete description, this one is brief and say",
"\"Observe agora a caixa preta e verá que o orifício é mais negro que a própria caixa, destacadamente. Leituras a respeito do ",
" resolvem o por... | [
"Where does it describe the behaviour of the laser like you mentioned in your post? Or did you conduct the experiment yourself and make those observations?",
"The experiment in the link you provided is just an experiment showing how a blackbody can be modeled as a cavity in a box. "
] |
[
"Why are there no computer simulated drug trials?"
] | [
false
] | We have computer simulations for car crash tests, atomic explosions, black holes, even the whole universe. Why can't we just create a model of the human body and use it to research the effects of new drugs? | [
"Modeling an entire organism, even a bacterium, is orders of magnitude more complicated than our most advanced computer simulations of biological systems. Today, we can model in explicit detail the dynamics of a large protein for a few microseconds, and even a simulation of that scale requires an enormous amount of... | [
"We do, sort of. Complex proteins interactions are simulated with computers, but it's not really worth it to simulate the rest of the human body because...",
"-It takes a massive amount of computing power",
"\n-It's unlikely any simulation would be accurate enough to verify the actual effects of the drug on the... | [
"It's unlikely any simulation would be accurate enough to verify the actual effects of the drug on the human body",
"There's the crux. GIGO. Garbage in, garbage out. We just can't accurately construct a model of what's going on inside the body. We have simplistic models that help predict, but the real thing is so... |
[
"In E=MC2 - how does it work that you can multiply meters per second by kilograms and come out with joules?"
] | [
false
] | I was just watching a BBC show about "Beautiful Equations" and this is one of the famous equations that it discussed. However, this question still lingers in my mind. In most everyday mathematics that one does over the course of a normal life, the units are the same throughout the equation. What makes the kilogram, the meter, the clock second, and the joule special - so that you can convert from one to the other in this manner? | [
"Joules are defined as a kilogram * meter",
" /second",
"A meter is defined as the distance that light covers in 1/299,792,458 of a second. A second is defined as the amount of time it takes for a cesium atom to oscillate 9,192,631,770 times. A kilogram is defined as the amount of mass in a silicon cylinder ... | [
"This. Even from the start, the units of energy are Work = Force * distance\nSo, J = N * m. But F = m",
" m/s",
" Put it all together and J = N * m = kg * m",
" /s"
] | [
"In fact, the equation can be elegant and simple, because the newton itself was invented in the process of drawing up equations such as this one, right?",
"The relationship between the masses of objects and their gravitation wasn't created by Newton; the inverse-square relation exists whether we knew it or not.",... |
[
"What increases fluid intelligence?"
] | [
false
] | null | [
"This is actually a question the field struggles with. TL;DR: Practicing helps, but only for what you practice.",
"There are plenty of studies out there showing enhancement but the consensus seems to be that one cannot increase overall general fluid intelligence (what's sometimes referred to as \"Gf\") but one ca... | [
"Not entirely true, There are multiple studies showing positive results using Dual-n-Back 20 sessions, 4 or 5 times per week."
] | [
"Interesting - I'd love to read them. Do you know if it's improvement on n-back tasks, or does it generalize to other things as well (and if so what?)"
] |
[
"How can we imagine two (or more) temporal dimensions?"
] | [
false
] | I know that we live in three spacial dimensions and one temporal, but we are able to imagine how a four dimensional cube looks like, so can we also imagine how two temporal dimensions would work? | [
"I'm not an expert here, but ",
"physicists have considered cases with this possibility.",
"Also, if anyone posts the \"imagining the 10 dimensions\" video, that is simply not based on science. It's a fiction. A popular internet fiction."
] | [
"Typically, when we talk about physics and equations of motion, we mean equations that allow us to predict a particles location at a later time if we know it's location, velocity, etc. at some earlier time.",
"But if we have two temporal coordinates, say t and u, on top of spatial coordinates x,y,z, well then it ... | [
"God, I hate that video so much. People become genuinely interested, go search to learn about higher dimensions, and instead they get that nonsense. ",
"For laymen, I generally post ",
"this video",
" from Cosmos in response to that video."
] |
[
"Has long term vegetarianism led to any discernible genetic differences in South Asian populations?"
] | [
false
] | null | [
"(layman here)",
"I would imagine there's not really enough data.",
"First of all, \"long term\" vegetarianism isn't that long of a term in a biological sense. I mean, King Ashoka was 270BCE?",
"Second, even in societies where the main religion has vegetarianism as a tenet, not everyone is vegetarian. I wou... | [
"Without the current system of global infrastructure and technology it would be night impossible to locally obtain everything that you need for a vegetarian diet.",
"In addition, any civilization without agriculture would likely be unable to grow or thrive because of the immense amount of time they would need to ... | [
"I absolutely agree. I'll add to that by saying that vegetarianism would have negative health consequences for some people if it weren't for things like iron supplementation, etc. That said, in the modern world enmass meat eating has its problems in terms of the environment and logistics because of things like th... |
[
"Why does water have no taste or lack thereof?"
] | [
false
] | I asked my Geosystems teacher this question and he didn't have answer so I thought could help me :) | [
"Because you don't have taste receptors for it. There wouldn't be much point in having them, since your mouth is nearly always full of water. ",
"However, there are animals who can smell water, and they use that sense as a method to find sources of water in dry climates. Though I can't find a good source for i... | [
"Spitballing here, but probably by wind direction? How else would anything locate the source of an odor?"
] | [
"Spitballing here, but probably by wind direction? How else would anything locate the source of an odor?"
] |
[
"Why can't we handle division by zero the same way we handle the square root of -1?"
] | [
false
] | Define 1/0=m Three dimensional space with axes Real, Imaginary, m Using m whenever division by zero occurs may allow carrying through proofs until m cancels. Identities: If m = 1/0, 0*m=1 1/m = 0 | [
"Because allowing division by zero results in ",
"completely broken mathematics",
". Let's just do some simple algebra with what you've proposed:",
"m = 1/0\n1/m = 0/1 Take the inverse of both sides\n2 * 1/m = 0/1 * 2 Multiply both sides by 2\n2 * 1/m = 0 * 2/1 Rearrange the right side\n2 * 1... | [
"Yes, you can make it say 0 = 0, but you can move terms around to make it say ",
". That's the heart of the problem: by using completely valid algebraic operations, I came to a contradiction when I allowed division by zero. Allowing division by zero makes all of algebra break down."
] | [
"Let's go from your 1/m = 0 identity. Adding 1/m to both sides, we have 1/m + 1/m = 1/m. Now, multiplying both sides by m, we have 1 + 1 = 1. So you can see how such a system yields inconsistent results pretty quickly.",
"To dig a bit further more into where the problem lies, recall the definition of division: k ... |
[
"Flair:'Maths' If the limit of ratio A(N+1)/A(N) in the Fibonacci sequence approaches the golden ratio, how is it an irrational number?"
] | [
false
] | If the ratio of two aleph-null sized numbers is still irrational then my question is trivial. However it still seems that there exists a concept of a number whose rational can be expressed as an irrational number but that might be common knowledge. Edit: sorry for the screwed up title I thought the flair: 'maths' would be the mathematics flair. | [
"The limit of a sequence of rational numbers isn't necessarily (or even most times) a rational number, since the set of rational numbers isn't ",
"complete",
". Another example of a sequence with that property is the one indicated in that page, that converges to sqrt(2)."
] | [
"The sequence {A(n+1)/A(n)}, as n goes from 1 to infinity, may approach an irrational number. ",
"Just because a sequence of values is composed entirely of rationals, that does not mean that the limit is rational.",
"In fact, one of the ways to define the real numbers (ie, the rationals and irrationals together... | [
"A rational number is a number that can be represented as a ratio of integers. Each element in the sequence A(N+1)/A(N) is a rational number, but the golden ratio is not any element of the series, it is only the limit of the series.",
"You seem to be trying to say \"well, A(Infinty) is an integer, and A(Infinity+... |
[
"How do cruise ships prevent almost all the rocking from the sea?"
] | [
false
] | The only time I felt it was during a storm, and it was much less than I expected. | [
"Size",
"Design - specifically metacentric height",
"Roll stabilizers - special fins that help counter-act roll forces as the ship is underway",
"Active ballast control - computer control ballast system that moves mass around to reduce the effect of roll"
] | [
"The ship has in some ways a resonance frequency about how quick it can rock back and forth. If the waves are small enough, their frequency is not right and the ship will simply ignore it. Its too slow to respond to those quick variations in forces. They require slower stronger forces created by bigger waves."
] | [
"Used to work on a cruise ship. The boats are very large, so they take a decent amount of time to rock and back forth. The other part of the equation is that the further you get from the center of the ship, the more pronounced the motion is. You'll notice the promenade deck is on deck 7 and most of the things ar... |
[
"How do our eyes see the stars much better than a camera?"
] | [
false
] | null | [
"They dont, if you could remove an eye and plug it into a printer, open the shutter for a tiny fraction of a second the picture you would get would be more or less jack. ",
"Now take a camera, have the shutter open and close about once a second for minutes, have a powerful computer that stabilises the image, adj... | [
"take a camera, have the shutter open and close about once a second for minutes, have a powerful computer that stabilises the image ",
"Your description of camera + software explains how a camera can capture very dim light sources (potentially better than the human eye), but it does not explain how the eye with... | [
"The sensor in a camera might be bigger than the sensor in your retina, but it’s trying to capture a whole scene. Hold your thumb up at arm’s length - that’s about the size of the image your macula captures in any given instant. The macula is the part of your retina that is densely packed with cone cells, which are... |
[
"Is it possible to set something on fire by pouring boiling water on it?"
] | [
false
] | null | [
"yes, if it is a water reactive substance like calcium carbide water will react exothermically and ignite the gases produced"
] | [
"To expand on this, there are a myriad of materials we call Pyrophoric which spontaneously combust when treated with air. Typically the reason they do combust is moisture in the air. The most common example is sodium metal."
] | [
"Besides a chemical reaction with water itself, anything that has an ",
"autoignition temperature",
" below 100 C could theoretically be ignited by heating it with boiling water. However, if the material did not react with water and you poured the water on top of it you might simply smother any flames that wou... |
[
"Do mitochondria undergo secondary endosymbiosis?"
] | [
false
] | I've frequently read about chloroplasts undergoing secondary endosymbiosis, but not mitochondria. I've tried looking it up but I couldn't really find anything explaining why this would be the case. Is it just because mitochondria were incorporated so early into the eukaryotic lineage, that pretty much every eukaryote has one? And so there isn't a need to grab one from another eukaryotic species? | [
"Are you asking if there are two or more lines of mitochondria, or if mitochondria were taken from one eukaryote by another, making their phylogeny not match their host?",
"If the former: as far as I know, ",
" mitochondria derive from the same primary endosymbiosis event. The phylogeny of all eukaryotes and al... | [
"Yeah, since extant eukaryotes had mitochondria ancestrally, there wouldn't be a strong selective benefit to picking up a secondary one. Whereas picking up a secondary plastid allows you to do photosynthesis. ",
"Some eukaryotes, particularly parasites and anaerobes, have greatly reduced or in one known case enti... | [
"I assume “secondary mitochondria” refers to cases where a eukaryote established an endosymbiotic relationship with another eukaryote and integrated the symbiotic eukaryotes mitochondrion (i.e., a case similar to secondary plastids)",
"I can’t think of any potential examples. It would be hard to establish using p... |
[
"Why is radioactivity measured in half-lives?"
] | [
false
] | null | [
"Because it is a fundamentally random process. A uranium 235 atom created a micro second ago, and one created 50 million years ago have identical chances to survive the next 10 seconds."
] | [
"The half-life of a radioactive isotope is how long it takes for half a large sample of that isotope to undergo radioactive decay, or conversely how long it would take for a 50% chance that any single atom of that particular isotope to undergo decay. The half-life is constant over time, so describing the decay of a... | [
"I think that's the best explanation I've seen yet"
] |
[
"Why can't we film a TV or computer screen clearly?"
] | [
false
] | Whenever someone takes a photo or takes a video of a screen it usually comes out distorted in one way or another depending on whether it is video or a photo. Why is this? | [
"This is the result of aliasing - a difference between a frequency inherent to the observed phenomenon and the sampling frequency used to record it. This is why you sometimes see wheels appearing to rotate backwards on vehicles in film. The frame rate is such that each successive frame happens to catch a spoke in ... | [
"This phenomenon is caused by How TV displays an image on the screen. The TV will change the image by changing each individual pixel from the top left moving right, and work it's way down. The rate at which it does this is so high that we don't notice the change and appears to be a smooth moving image. When we see... | [
"Thanks a lot guys. I knew you could help me out."
] |
[
"Why does rate of reaction not change when you add product?"
] | [
false
] | According to Le Chatelier, wouldn't the rate of the forward reaction slow down if product was added? | [
"The rate of a reaction is only dependent on the educts. That makes intuitive sense, because why would the educts care if there is product around? The reaction in the forward direction only depends on the interactions of the educts, after all. If you add product, the rate of the reverse reaction increases, again, b... | [
"I would like to add a side note, a minor exception. If the reaction is surface mediated then the products may reside on the surface to some degree and therefore poison the surface. With less surface area available for the reactants the reaction will start to slow. A good chemist wouldn't select such a surface/ c... | [
"That's not exactly correct. Take a unimolecular reaction A -> P as the simplest example. The reaction rate depends on the concentration of A and the rate constant k, d[A]/dt=k[A]. That's a consequence of the fact that only those molecules of A that have a certain energy follow the reaction path and the amount of t... |
[
"Could humans ever evolve to a point where certain races of people could'nt reproduce with each other?"
] | [
false
] | [deleted] | [
"I don't know, maybe the boat will return in the form of interplanetary colonisation. I mean suppose that space travel remains a difficult challenge, for all the reasons we have to suspect it may. Maybe we build a few colonies, but they remain largely independent, biologically isolated groups. Now you have new sele... | [
"That boat has pretty much sailed. Due to the transport options and freedom of travel we have now, there is more mixing of racial genes right now than at any other point in our history."
] | [
"That doesn't seem to be a good argument because adaptation by natural selection does not occur at a constant rate.",
"Your example does not mean at all that speciation could not happen within 40000 years."
] |
[
"Do veins have the same pattern for all humans?"
] | [
false
] | I suspect major arteries might have the same layout in all of us, but what about smaller ones? | [
"Even some major arteries vary a lot from one person to another, so veins, especially smaller ones, vary a lot too. There are of course veins, that are in the same place in the majority of people, but a majority is still not much. Smaller veins (arteries too) vary so much, that nobody even puts them in anatomy text... | [
"I feel like with that statistic, anatomically correct is not a firm definition"
] | [
"Yes I kinda wanted to put quotes on that, but was afraid to end up in ",
"r/suspiciousquotes",
" :D what I meant was, that only that amount of people have the most common, I guess textbook common, variation of everything - no more or less of anything and the most common blood vessel pattern."
] |
[
"Why do people make definitive statements about the R0 of a virus? Is it not a relative term?"
] | [
false
] | I see people say that covid's R0 is 'x', or the flu has an R0 of 'y', but is the R0 not a variable that can change depending on how people, governments, etc treat the spread of a virus? | [
"Strictly speaking when you hear reports of the R of the current Coronavirus being this figure or that figure in different locations or at different times the number being reported is the ",
" reproduction number, Re, i.e. the average number of people an infected person will infect ",
"The R0 is something diffe... | [
"",
"Yes, it can vary depending on circumstances, as noted in a recent NY Times article. A quote and the URL below. See the sentence in bold for a direct answer to your question.",
"\"When the virus first emerged in China, epidemiologists scrambled to understand how it spread from person to person. One of th... | [
"It looks like R0 still depends on typical behavior in a place though, and therefore cannot be constant. For example, a town populated mainly by meatpacking workers (who are constantly in close quarters with each other) will have higher R0 than a town populated mainly by loggers because their ordinary day-to-day be... |
[
"Harmful effects of Cola drinks: What are they? And provide links to actual studies"
] | [
false
] | I've always heard of the harmful effects of Cola drinks in many a conversation and newspaper/magazine article. Besides the obvious obesity issue, I've heard about liver and even stomach damage, among other crazy theories. I'd like to know how much of it is real science. Any doctors care to chime in here? Linking to actual studies supporting your claims is not absolutely necessary but it's a huge plus! I really want to see some literature on this matter. | [
"http://www.youtube.com/watch?v=dBnniua6-oM",
"This video talks about the metabolic processing of fructose being the same as that for alcohol and having the same effect on the liver. "
] | [
"Great reply. This is exactly the kind of stuff I'm looking for.",
"Can anyone poke some holes into the video? It's important to know where he's reaching too."
] | [
"Consider this as a scaffolding for the real answers from scientists: drinking what is essentially pure sugar plus a number of non-nourishing chemicals is quite unhealthy. "
] |
[
"What can we deduce from 3D renderings of protein?"
] | [
false
] | [deleted] | [
"To determine things like how the protein changes as it works people do things like crystallize the same protein with no ATP, with ATP (nonhydrolyzable analog), and with ADP (or ADP analog). Then you can compare the structure before/after/during an ATP hydrolysis structure.",
"If you know which domains of a prote... | [
"That's awesome! Thanks!"
] | [
"Just once concept I've been doing lately in frontier molecular biology, that one of the best understanding for how you get post-translational modifications such as glycosylation or phosphorylation of the serine and threonine amino acids on proteins is purely through the 3D shape of the protein around those amino a... |
[
"How far could a modern telescope see if it was the diameter of the earth?"
] | [
false
] | First of all i understand that modern telescopes actually absorb energy wavelengths and the way we interpret the data through computers isn't really the same thing as how a human eyeball "sees". -If, hypothetically, a satellite was built that was around the diameter of the earth; how far could it see? I guess i realize that by "far", I mean , "how far back in time" as the light was emitted long ago. With the size of our universe is it feasible we would actually be able to see anything in any detail; is our technology limited by the size of the receiver or by the number of pixels/ method the data is recorded? | [
"I have no answer to your question.",
"With the size of our universe is it feasible we would actually be able to see anything in any detail",
"Even though Space might be infinite, the radius of the visible universe is calculated to be about 46 billion light years (",
"source",
"). That's where we then see t... | [
"This is not an answer to your question, but we already do have telescopes the diameter of the Earth. This is achieved by pointing a telescope in the same direction into space 12 hours apart, that is, when the telescope is on opposite sides of the planet."
] | [
"The ability to see back in time is referred to as sensitivity in instrumentation terms, that is things further away (in space/time) are dimmer. So less energy reaches us.",
"The bigger the aperture of your instrument the more energy you gather from the source, with a few assumptions. To go much furhter though ... |
[
"I would post this to /r/neuroscience, but it has a rather low readership so my question is:"
] | [
false
] | Can anyone tell what permanent medium-to-severe suppression of CNS Acetylcholine can have in effects? The medication in question is Biperiden (Akineton(R) as brand name where I live). I feel constantly depressed ever since taking it, at points even to the point of suicidal ideation, and I'm worrying it's because of the mentioned meds. Thank you all and sorry in case this is inappropriate in AskScience. (I tried googling up something conclusive but wasn't able to.) | [
"Not my specialty (ignore the badge), but you should talk to a (specialist) doctor about this not necessarily a scientist/researcher. ",
"I'm not saying this is inappropriate thing to ask, but scientific researchers aren't the most knowledgeable about side-effects of drugs (or consequences of abruptly stopping d... | [
"I'm a neuropsychologist, not a medical doctor, so please take everyone else's advice and go see your medical doctor. ",
"But yes, Akineton side effects can include depression - and it would be considered a \"rare but serious\" side effect (more common emotional side effects would include anxiety/agitation/confus... | [
"To OP:",
"While there are some doctors on askscience, the majority of us are scientists who don't know anything about clinical drugs and don't know enough are your specific question (due to our extremely high degree of specialization) to give exact answers. You may be better off posting in somewhere like ",
"/... |
[
"I saw a post about bill sharks that were stranded in a golf course lake and thriving. If left alone with a sufficient food supply, how long would it take to see evolutionary changes?"
] | [
false
] | Here is the original link. | [
"Are bill sharks similar to loan sharks? Anyway they would probably die off pretty quickly, not enough DNA for a healthy new population to form "
] | [
"Just as a note, evolution is a constant process. Changes occur in every generation; you contain several mutations in addition to your parent's DNA. So we could see evolutionary changes in the first offspring, and the only question is how dramatic a change we want for us to decide to draw a line."
] | [
"are you taking about micro evolution or macro evolution"
] |
[
"What would be the best way for me to learn Matlab outside of class?"
] | [
false
] | I was wondering if any of you knew any good resources or books that would help me quickly pick up Matlab. I have experience using basic Python, so I'm sure that would help. I'd rather not take a class since I'm trying to learn this as quickly as I can, although I know the guidance and practice from a class would greatly help. | [
"Project Euler."
] | [
"Working through Project Euler problems is my favourite way to introduce myself to the syntax of any new language. Nice suggestion.",
"Edit: I should say that when doing these problems you should investigate solutions that use matrix operations instead of for loops and things like that. The real power of MATLA... | [
"when doing these problems you should investigate solutions that use matrix operations instead of for loops and things like that. The real power of MATLAB comes from the what you can do with matricies. ",
"This is the best advice here. You should very very rarely ever use FOR loops in matlab. If you can learn t... |
[
"why don't gas giants solidify?"
] | [
false
] | So, I can only come up with two potential energy sources that can keep them gassy: - centrifugal force - internal heating (similar to a sun) both of those don't really make sense to me, since 1. as far as I know they are (at least some of them) very cold, and while they rotate quicker than earth relative to their size, they don't even nearly rotate quick enough to keep all their matter in the form of a gas. So how come they don't collapse ? | [
"At the temperature they're at, they're gasses.",
"There's not a lot of ways to loose heat, besides radiating in space. If you're orbiting a sun there's an influx of heat. These usually balance each other. So temperature should remain constant."
] | [
"Pretty much everything will solidify under a state curve with a low enough temp and a high enough pressure. What amstan is saying is that the equilibrium of energy in & out on these planets is such that the temperature doesn't get low enough to condense the gas. The gas itself is an insulator in some cases, refl... | [
"So they are nearly entirely composed of gases that solidify under very high pressures with very low temperatures? I mean other planets with less mass have frozen gases on them (methance, co2)"
] |
[
"If some elements have such a short half-life, why are they still here?"
] | [
false
] | [deleted] | [
"An ",
" doesn't have a half-life, each individual ",
" of every element has its own half-life.",
"There are some radionuclides on Earth whose half-lives are much smaller than the age of the Earth, for example carbon-14.",
"It just means that these nuclides are being produced by some processes that happened... | [
"That's precisely why carbon-14 is such a good tool for dating organic artifacts. As organisms absorb carbon from the environment to build their bodies while alive, the ratio of radioactive carbon will remain more or less constant. But when they die, they're no longer \"repaired\" with new materials, which allows u... | [
"They eat food with carbon in it, thereby renewing the supply of carbon-14.",
"edit: a word."
] |
[
"What physically stops two like poles of a magnet from touching?"
] | [
false
] | I get that the magnets each form a magnetic field, but what fundamentally causes this repulsion between like charges? | [
"but what fundamentally causes this repulsion between like charges?",
"The electromagnetic field is fundamental. The four fundamental interactions are gravity, electromagnetism, the weak nuclear force and the strong nuclear force. Static magnetic fields, such as created by permanent magnets, are just particular f... | [
"I think you should first watch ",
"this",
" and then ask follow up questions :)"
] | [
"Some people say that a magnetic field is just what an electric field looks like from a certain reference frame. While this is partially true, it is misleading. ",
"Would like to second that. I see people using the example of calculating the force on a ",
"charge near a wire in different reference frames",
" ... |
[
"Mathematically speaking, if a given game of Sudoku, in its initial state, has only one possible outcome, will it always solvable without having to resort to guessing a cell's value?"
] | [
false
] | I have long felt this must be the case, but my limited mathematical skills prevent me from proving this | [
"The issue is that 'trying out' a particular solution and then following the logical consequences of that solution is one of the fundamental techniques for solving a sudoku puzzle. Often, following the logical consequences of a solution can be done without writing anything down, but that depends on the limitations... | [
"Unless the person who made the puzzle made a mistake a sudoku puzzle has only one correct solution and enough information from the start to solve it without guessing."
] | [
"A puzzle with only three or four numbers can have multiple answers and would require making guesses but this is not a proper sudoku puzzle."
] |
[
"Would someone please explain how operators like multiply/divide and XOR work in computing and simulations?"
] | [
false
] | I'm trying to freshen up my knowledge of particle and fluid simulations for visual effects and I still don't fully understand what's going on when I use these operators. For instance what is happening when I use a divide operation to divide the age of a simulation using a gradient ramp texture that has grey scale values 0-1, or values greater than 1 that is connected to a color/diffuse channel. Same Question but using procedural fractal map instead? And what is happening when you use the XOR operation. | [
"Exclusive OR: One or the other are true, but not both (or neither for that matter).",
"A XOR B | Result\n----------------\n0 | 0 | 0\n1 | 0 | 1\n0 | 1 | 1\n1 | 1 | 0\n"
] | [
"The quickest way to remember XOR:",
"Are A and B different? yes=true, no=false"
] | [
"Wikipedia has articles that describe digital division and multiplication.",
"Division",
"multiplication"
] |
[
"The first reports of Mad Cow Disease (BSE) were filed nearly 30 years ago in Britain. Have we seen the worst of its effects by now?"
] | [
false
] | Growing up in Europe, the late 80s all through the 90s, we were constantly bombarded about BSE and its potential effects on the population. Those born in the 90s or after may not remember or know too much about that whole saga. As I recall, in France, we heard about how a huge chunk of the population would be developing Creutzfeldt-Jakob Disease in the next 20 to 30 years. Here is a brief of the spread of BSE. I am sure it is incomplete but at least gives an overview of how things happened. January 1993 - The BSE epidemic in Britain reaches its peak with almost 1,000 new cases being reported per week. 1996 - The first case of variant Creutzfeldt-Jakob Disease is reported. I can't seem to find any data that suggests a sudden upswing as one might expect if the predictions of the experts at the time were correct. Are we in for a sudden burst of Creutzfeldt-Jakob Disease for Europeans? Should we be worried? | [
"Probably we don't need to be worried that a huge chunk of the population will develop the disease, but there are still things we don't know about how the disease develops. You can see a chart ",
"here",
" of diagnosed cases in the UK. Although the total deaths from CJD are increasing, the green line is the one... | [
"A virus self-replicates, using the contents of a cell as building blocks.",
"A prion is a more stable form of a protein; if you've ever seen ",
"supercooled water",
" freezing, that's similar in a way: the molecule itself doesn't change chemically. Proteins are structurally much more complicated than water, ... | [
"This report",
" suggests it might just be increased diagnosis because the disease has been in the news. Apparently the trend is the same in many countries."
] |
[
"How can I find the amount of Energy contained in a system by measuring the temperature?"
] | [
false
] | null | [
"It’s not necessarily possible to calculate the total energy of a system given only its temperature. For a classical ideal gas, the relationship is E = 3NkT/2. So you are required to know both the temperature and the number of gas molecules. For more complicated systems, there are more complicated relationships bet... | [
"So of I knew the number of particles withing the system I would know the energy from the definition of temperature being \"the average kinetic energy of the particles of a system\"?"
] | [
"For a classical ideal gas, all of that is true."
] |
[
"What exactly is happening when you mix sugar into Sulfuric acid?"
] | [
false
] | It turns black, and I think the acid somehow strips the Oxygens and Hydrogens off of the C6H12O6 molecule, but how does that happen and what products are left? Also I noticed that if you add Nitric acid into the solution of carbon black sugar residue, the carbon black residue seems to disappear, what exactly is happening there on the molecular scale? | [
"Sulfuric acid is a strong dehydrating agent. The sugar undergoes a dehydration reaction, leaving water and elemental carbon behind.",
"Nitric acid is an oxidizing agent, and will oxidize your elemental carbon into carbon dioxide."
] | [
"When you say elemental carbon, surely it can't just be C sitting there unconnected to any other carbons. Do you know what structure the carbon would form?"
] | [
"It'll be ",
"amorphous carbon",
", similar to soot. It'll be connected to other carbons, as well as having dangling bonds and bonded to other atmospheric elements."
] |
[
"If a spider builds its web in a bad spot, will it be smart enough to give up after a day or two and move elsewhere, or will it just starve to death because it can't realize it made a bad decision?"
] | [
false
] | [deleted] | [
"Orb Weaver spiders, the most common group of spiders that build spiral wheel-shaped webs, generally build a new web each day. They'll eat the old web in the evening, rest for an hour or so, and then spin a new web."
] | [
"Spiders are known to relocate if they have a low prey capture rate",
".",
"The research citations are from ",
"here",
" but are behind a paywall."
] | [
"That doesn't speak to whether or not they relocate at any point though.",
"The ones I've observed (also orb weavers) often retain the same location over extended periods."
] |
[
"If you made a range of paints that were x-ray, microwave, or radiowave 'coloured', would they appear black to us?"
] | [
false
] | Also, it seems that many of our paints/colours were originally created from naturally occurring pigments in plants etc. Do substance occur in nature that would only reflect far outside the visible spectrum of light? | [
"The way in which they interact with x rays or infrared etc would be irrelevant to how they appear to us, the only thing we can see is which parts of the visible spectrum they reflect. So if you had 2 red paints, one reflects x ray and one absorbs it, they would both just look like red paint to us."
] | [
"Honestly not really sure, x-rays and radio waves have vastly different wavelengths to visible light, so they start to interact with matter differently to how we are used to with normal light. The wavelength of x-rays is similar to the spacing between atoms, so the specific atomic geometry and orientation of whatev... | [
"I understand what you're saying. But what I'm getting at is if it would be conceivable to have a paint which only reflected x rays or radio waves?"
] |
[
"Why does solar wind speeds up when moving away from the Sun?"
] | [
false
] | The initial velocity of the solar wind is subsonic. As it moves away from the Sun in a radial direction, it is expanding in area and thus should be slowing down instead of speeding up. My compressible fluid professor mentionned that the Suns gravity has the effect to speed up the flow but didn't elaborate. Is someone here able to explain me more in detail what is happening? | [
"Thanks for your answer. My other question is now: If the gravity gradient is indeed acting like a converging nozzle, how does the flow pass the sound barrier to reach velocities over Mach 1? In the case of a strictly converging nozzle, the flow would simply choke at the throat of the nozzle and it wont be able to ... | [
"Thanks for your answer. My other question is now: If the gravity gradient is indeed acting like a converging nozzle, how does the flow pass the sound barrier to reach velocities over Mach 1? In the case of a strictly converging nozzle, the flow would simply choke at the throat of the nozzle and it wont be able to ... | [
"I don't know what was in the deleted comment, but your reply is making me rather nervous. My understanding is that firstly the mechanism behaind the solar wind aren't well understood. The acceleration is likely due to interaction between the charged particles that make up the wind, and the sun's magnetic field. Ph... |
[
"Why does a faster moving boat create smaller waves?"
] | [
false
] | With two boats of the same size and hull shape, why does it seem as though if one were moving faster it would create smaller waves compared to a slower moving one? | [
"Hydroplaning. Generally, the faster a boat goes, the less of it’s hull actually touches the water. Different hull shapes and designs will produce different results based on the use of the boat. Less contact with the surface of the water will produce less wave action.",
"Also, keep in mind that this only really a... | [
"You probably could hydroplane a cruise ship but it would be lightly impractical."
] | [
"Now I’m imagining hydrofoils on a cruise ship to help and have to believe there’s a downward pressure wave causing chaos undersea to generate enough lift to get a 200k ton cruise ship aloft"
] |
[
"This is getting tossed around as debunking climate change."
] | [
false
] | Found claiming that this study debunks climate change. I'm slowly working my way through it now, but, well, I'm not a climatologist. Can someone help break down for me? | [
"No, it certainly doesn't. This ",
"realclimate article",
" has a good explanation of what's going on in the new study, and what its implications are.",
"Some excerpts:",
"The most exciting–and in our view important–development is that they seem to have greatly ameliorated the “divergence problem” that has ... | [
"Yes. It's hard to see how a cooling of 0.3º per millenium could be seen as negating the recent warming of 0.3º ",
" (one hundred times bigger!) or the patently obvious ",
"observed effects",
" of recent climate change.",
"I guess some people just aren't very bright."
] | [
"From a quick skim through, it seems that they are claiming that global temperatures are on a general decline. This may well be true, but global warming as we generally consider it is caused by man-made greenhouse gasses, which have only been produced in significant quantities in the past hundred or so years.",
... |
[
"Can children eat rare or med rare steak?"
] | [
false
] | null | [
"None that I can think of. The inside of a piece of uncut meat(beef) is sterile. Make sure that the meat isn't mechanically tenderized or injected with a brine solution. ",
"The problem arises when meat is ground because then the potentially contaminated outside becomes the same as the previously sterile inside."... | [
"Chickens are able to have salmonella within their tissue. This occurs in around 1/100000 chickens. This is a low number, but we eat a lot of chicken. Also, the majority of supermarket chicken has been injected with a brine solution to help maintain moisture and tenderness since they are so low in fat. If you grow ... | [
"other than taste, is there a reason why having slightly under-cooked chicken breast is a bad idea? i know that salmonella is considered a potential worry, but wouldn't that require the meat to have been infected with salmonella in the first place (ie. an uncommon occurrence)?"
] |
[
"Why can methane that is built up in landfills not be used as energy in some way?"
] | [
false
] | I recently learned that landfills have columns in various spots to relieve methane that builds up from decomposing waste. If this wasn't done, there is a possibility of a fire burning the throughout the landfill for a long time and posing a serious hazard to people. So as opposed to letting the methane just rise into the atmosphere, why isn't anyone trying to collect it for energy purposes? Or is this not even practical? | [
"We do. The EPA has a program to add incentives to this - ",
"link",
". As always, the issue with a potential energy source isn't \"can we do this?\" It is \"can we do this ",
"?\""
] | [
"No. The limit is how much it costs to collect and use the gas.",
"The amount of money the government puts in to start the project, however, determines how well the options to extract it are examined and developed. "
] | [
"One of the larger problems for doing this cost-effectively is that the landfills do not simply emmit methane. The gas mixture varies depending on the microbacterial flora (which is usually not controlled) and the ingredients (which vary and are likewise usually not controlled). Even within one landfill the mixture... |
[
"Question about drafting.."
] | [
false
] | Say if Vehicle B was driving behind Vehicle A close enough to be inside of Vehicle A's slipstream.. It would obviously improve Vehicle B's fuel efficiency. But my question is: would it decrease Vehicle A's fuel efficiency as if Vehicle A was having to "pull" Vehicle B? Also, would this be similar in water? I am a swimmer and there has been some debate about whether drafting on someone hinders the performance of the person who is doing the "pulling" (the person who would represent Vehicle A in the above scenario) | [
"It is justified and commonly used in Nascar."
] | [
"I don't have an answer for you, but I wanted to add another possibility (and piggyback the question I guess): I've heard that in some cases it's possible for the presence of the drafting person to actually ",
" the person in front by improving the slipstream (like putting a better tail on an aerodynamic geometr... | [
"If vehicle B is close enough, it will actually help vehicle A by reducing induced drag, in this case the suction behind the vehicle. There is no penalty to vehicle A because it is not actually pulling vehicle B. Vehicle B is just enjoying less friction in the air that Vehicle A pushed (and pulled).",
"The densit... |
[
"Why doesn't the west coast get any hurricanes or tropical storms?"
] | [
false
] | I've been living on the west coast for 18 years and had never had a problem with hurricane, but every fall the east coast always gets a storm. | [
"We do get hurricanes, but they are farther south. If you are in Southern California, a lot of the tropical weather we get here in the late summer/early fall is the \"left overs\" of the hurricanes that peter out over land in Baja or the colder northern waters off the Californian coast. ",
"Hurricanes get their e... | [
"Yes, there are anti-clockwise currents in the Southern Hemisphere. And yes, there are associated hurricanes (in this context just called tropical cyclones) that can hit the east coast of Africa below the equator as well as northern and western Australia and across Indonesia. But yes, it is a messy picture with man... | [
"I found this a decent visualization of the hurricane path patterns. ",
"https://en.wikipedia.org/wiki/Humboldt_Current#/media/File:Tropical_cyclones_1945_2006.png",
""
] |
[
"Did the impact that created the moon have a substantial effect on Earth's orbit?"
] | [
false
] | I've read that the existence of the moon itself stabilizes Earth's orbit and makes the planet more hospitable to life, but I was wondering more about the impact itself. Do we know if there was a meaningful change to Earth's orbit after the collision? | [
"Yes it would have definitely changed the rotation rate of the Earth. That is the best we can say though as we do not know if the collision was more direct or more of a glancing blow. What makes this problem even harder is that the outward migration of the Moon and hence the spin down of the Earth is not constant i... | [
"What dukesdj is saying (I think) with the last sentence is that scientists are not entirely sure about what exactly happened; theories range from two objects coming from the same source material, never having colided, to total vaporization of both celestial bodies in a frontal crash - some fitting better into mode... | [
"What makes this problem even harder is that the outward migration of the Moon and hence the spin down of the Earth is not constant in time. There are a number of reasons",
"Just because I'm super-biased to start talking about atmospheres, here's another really interesting reason: Earth's rotation period can lock... |
[
"What are the anatomical differences between a left handed person and a right handed person? Especially internal differences?"
] | [
false
] | I didn't see anything asked here before | [
"Nurse here. None that I know of. "
] | [
"Tom, the male nurse, is correct. :P",
"Apart from the differences one might expect to find between two normal and right handed people. ",
"There are some expected differences in brain function, but as far as I know this is simply because the other hand is dominant same goes for the brain. There are some stu... | [
"Yep, murse here!",
"You make good points as far as brain hemispheric functions go between lefties and righties. ",
"I would add to your point that people with transpositions of organs generally have a lot of other issues do well. Many of them fair poorly. "
] |
[
"So two part question, is absolute zero the lowest temp possible? And is there an upper limit of temperature?"
] | [
false
] | null | [
"I just realized I don't think I'm smart enough to be asking questions here. ELI5?"
] | [
"Absolute zero is not the lowest possible temperature, because temperatures can be negative. However when a system is as cold as it can possibly be, its temperature is absolute zero. There is no maximum temperature, but if your system has a maximum possible energy, then in that state, its temperature is zero."
] | [
"When a thermodynamic system has its lowest or highest possible energy (if there is a highest possible), it has a temperature of absolute zero. Absolute temperatures ",
"can be negative",
", but that doesn't mean that the system is colder than absolute zero; in fact it's hotter than it would be at infinite temp... |
[
"Why are your ears, nose and throat all connected?"
] | [
false
] | null | [
"Because once upon a time your ancestors were fishes.",
"I'll do this one organ at a time.",
"Your throat is derived from a structure called the ",
". The pharynx in fishes is essentially the tube between the mouth and the entrance to the esophagus. This tube, in fishes, has holes in the side. These holes ... | [
"Thanks. That really helps. "
] | [
"No problem!"
] |
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