title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Could Enigma code be broken today WITHOUT having access to any enigma machines?"
] | [
false
] | Obviously computing has come a long way since WWII. Having a captured enigma machine greatly narrows the possible combinations you are searching for and the possible combinations of encoding, even though there are still a lot of possible configurations. A modern computer could probably crack the code in a second, but what if they had no enigma machines at all? Could an intercepted encoded message be cracked today with random replacement of each character with no information about the mechanism of substitution for each character? | [
"As with most cryptographic systems, the flaw was never the cipher algorithm, but the humans using them."
] | [
"As with most cryptographic systems, the flaw was never the cipher algorithm, but the humans using them."
] | [
"It's worth mentioning that, as famous as the Enigma machines were, Germany used other encryption machines such as the ",
"Lorenz rotor stream cipher machines,",
" which were cracked by British cryptanalysts despite their never having gotten their hands on a physical example. As with the Enigma, though, this wa... |
[
"Why Can't the brain interpret the image it sees to make things clear to people who need glasses?"
] | [
false
] | null | [
"Yes the brain makes us ignore blind spots, this is not the same as filling in the missing visual information. With blind spots we just don't notice that nothing is there and if we do it is usually just a white or black spot or a kind of smear of the images around it.",
"Maybe you multiple images idea would work ... | [
"No, this is akin to CSI type shows using computers to zoom in on or clean up images, in reality the image resolution prevents this. The brain cannot fill in the visual info it is not getting. "
] | [
"The brain cannot fill in the visual info it is not getting.",
"The brain does this all the time, with our blindspots and bloodvessels infront of our eyes.",
"Also it's possible to build up a higher resolution image from several lower resolution images taken from different angels, which is how the police make o... |
[
"How do we have images of the Milky Way Galaxy?"
] | [
false
] | null | [
"We don't. We have pictures of other galaxies. We know that the milky way is a spiral galaxy. So pictures of spiral galaxies stand in for the milky way."
] | [
"Pictures of the Milky Way from an outside perspective are just artists impressions."
] | [
"Ah. Thanks for the answer. I'm not really all that familiar with images of the cosmos so they looked extremely convincing to me."
] |
[
"Why is colorblindness specific combinations of colors or a certain amount of colors?"
] | [
false
] | [deleted] | [
"There are 7 types of color blindness. You have three types of cones that help you to see different colors. If any one of them are not there or does not work correctly you get different types of color blindness. Different combinations lead to different color blindnesses.",
"Because you only have three types of co... | [
"That was a journalistic exaggeration. Actual research shows that people who use different names for colors differentiate them a bit faster, if they are not given parallel linguistic task."
] | [
"Yes.",
"Look up the Himba tribe color perception experiments, they might blow your mind."
] |
[
"How many unique selves are implied by the major histocompatibility genes?"
] | [
false
] | From my understanding, there are about 6 major genes that are considered during transplant matching, and at least two of these - HLA-A and HLA-B both have thousands of variants leading to millions of permutations. So if we considered all of the major histocompatibility genes and the # of known variants, how many unique immune signatures would we get? If the immune system sort of defines "self", does this then give us an upper bound of the number of unique "selves"? Here's a quote from The Song of the Cell talking about the variants: Humans have multiple “classical” major histocompatibility genes, and potentially many others, of which at least three, and possibly more, are strongly related to graft compatibility versus rejection. One gene, called HLA-A, has more than a thousand variants, some common and some very rare. You inherit one such variant from your mother and one from your father. A second such gene, HLA-B, also has thousands of variants. You might have guessed already that the number of permutations between just two such highly variable genes is mind-boggling. The chances that you’d share such a barcode with a random stranger you met in a bar are vanishingly small (and all the more reason not to fuse with him or her).” | [
"There may be thousands of individual genes per locus (ie 7712 for A locus currently), but only about 100 of them are common. Many are caused by synonymous mutations or are found in the non-coding regions (introns). Also there is strong linkage disequilibrium between B-C as well as DRB1-DQB1 as those genes are ver ... | [
"There are three genes for MHC I, namely HLA-A, HLA-B, and HLA-C. You'll have one allele of each of them on each of your copies of chromosome 6. Last I checked there were 2041 alleles of HLA-A, 2668 alleles of HLA-B, and 1677 alleles of HLA-C. The number's probably higher now.",
"But that's just MHC I. There's al... | [
"That's really cool, thanks. So i suppose the actual numbers both of total possibilities and commonly encountered possibilities would be hard to estimate? Are there estimates anywhere? How do you define matching like is it based on how similar the output proteins are even if the genes might be very different?"
] |
[
"Are fish and other aquatic animals able to see regularly underwater or do they have the same blurring in their vision that humans have?"
] | [
false
] | If they can’t see regularly underwater do they have other senses to make up for it? | [
"When the prehistoric creatures moved out of the water, their eyes adjusted over time to the air. The way that fish and other aquatic animals see underwater is equivalent to what we see on land. Over time our eyes have adapted to our surroundings. "
] | [
"Well, most animals that regularly go between land and ocean such as reptiles or birds have a transparent eyelid that slides over their eye and protects it from irritation and salt while allowing them to see. I think I've heard/read that humans might have also had one but it stopped being useful and all that remain... | [
"Does that mean that if a fish was out of water it would have blurry vision like us underwater?"
] |
[
"Why do we swing our arms when we walk?"
] | [
false
] | null | [
"You swing your arms for balance. Try running with your arms straight down to your sides. (Don't actually do this)"
] | [
"I assume its angular momentum? The same reason why a bike doesn't fall over when in motion?\nBut then why do we do it when we walk."
] | [
"It's a counter-balance measure for during the swing phase of walking. Walking can be divided up into two phases, swing and stance, in which stance is when both feet are firmly on the ground and swing is when one foot is in the air. The swing phase generates some rotation on the body, which is counteracted by swing... |
[
"Why doesn't the Earth build up a positive charge from cosmic rays?"
] | [
false
] | We are continually bombarded with lots of cosmic rays, which are mostly bare protons. Shouldn't this mean that the Earth accumulates an excess positive charge over time? | [
"Cosmic rays are not the majority of particles striking Earth. In quantity they are greatly outnumbered by the particles of the solar wind, which are both positively and negatively charged. ",
"If the Earth does happen to acquire a slight positive charge, it will tend to repel positively charged particles and mor... | [
"will tend toward neutral.",
"Well, more precisely it would tend towards equilibrium. Even under your model, that equilibrium may have a net charge."
] | [
"That's correct. Thanks for catching it."
] |
[
"Can you have two colds at once?"
] | [
false
] | null | [
"You definitely can be infected with two viruses which cause the common cold at once, although it's probable that one will dominate over the other before long, with only one surviving and continuing the symptoms.",
"The epidemiology of the wintertime respiratory viruses (the viruses which cause the common cold) i... | [
"Yes, of course. Not just colds, you can be infected by multiple pathogens at once, which is one of the reasons why doctors might sometimes prescribe antibiotics to someone who is afflicted with a cold - to eliminate any bacterial infections potentially active even if it won't affect the virus. That's also the poin... | [
"That's not typically why a broad-spectrum antibiotic is prescribed. It's often done to start treatment before the bacteria can be cultured and classified. Or for prophylaxis where they are trying to prevent an infection (e.g. due to surgery) but they don't know in advance what you might be exposed to."
] |
[
"In Journey to the Center of the Earth one of Jules Vernes characters argues that the earth can't have a molten core. How can it?"
] | [
false
] | null | [
"Hi t7been thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the followin... | [
"Planetary Sci."
] | [
"'Planetary Sci.'"
] |
[
"Do any of the transition metals have negative charges? If so, why?"
] | [
false
] | null | [
"What do you mean by negative charges?"
] | [
"It sounds like you're asking if they have a lower oxidation states.",
"Being a simple organic chemist who really only cares about transition metals as they have relevance to coupling chemistry, the short answer is \"No.\" Metals like to donate their D-shell electrons lending to higher oxidation states, adding ex... | [
"Overall the short answer is no. When you have a bulk amount of a transition metal they have delocalized electron interactions which lead to \"positive nuclei.\" As for transition metal complexes, one in which you have a central inorganic atom that has formed a compound with some ligand structure, The total charge ... |
[
"A2 Physics coursework unexpected result? (LASER + Diffraction Grating)"
] | [
false
] | Whilst trying to get data for my A2 physics coursework (measuring the wavelength of light by the bending through a diffraction grating- not the best, but the alternative was literally paint-drying), I've been having some troubles with the diffraction grating; I should expect to see the brightest spot being straight ahead of the laser hitting the diffraction grating, a lá Phasor theory- however instead I'm getting the brightest dot offset to one side (dependant on the rotation of the grating, but not which side it's going though). Even more strangely, the offset between the brightest and the straight ahead is slightly more than between either and the next dot out. That is, between '0' (middle/straight on) and l1 (brightest dot) there's 1.6cm, whilst between l1-l2 and 0-r1 the gap is 1.5. (l2-l3 and r1-r2's 1.7 cm). I could take pictures if my wording isn't sufficient, but it'll have to be later as I'm about to go out. Please help me to explain this counterintuitive result! My teachers couldn't explain it either, putting it down to diffraction within the grating until I realised that it would always bend the same way, independant of the normal. They then were puzzled again. (The diffraction gratting is 300lines/mm, the laser is 532nm, but also happened with a 650nm. The behaviour was witnessed with several gratings of the same type, but a 15000line/inch (different make) and an unknown spacing grating I got for free from a uni visit don't have the behaviour). | [
"I'm doing my Ph.D in laser spectroscopy, so I think I can help you. Sadly I'm not sure I fully understand your premise. Maybe a cartoon would help ?"
] | [
"Here ya go; ",
"http://imgur.com/a/tAhbk",
"\nIf MS paint scrawlings aren't good enough, I'll get out the camera and take pics."
] | [
"Hello from a month in the future, just coming back to say that no-one could figure it out, although we now have a tentative explanation (although I don't like the explanation, I need to conclude the cwk somehow)."
] |
[
"I remember reading somewhere that major cities that experienced catastrophic fires (ones that burned down the majority of the city) converted to gridded road systems, whereas those that had no major fires didn't. Is there any truth to this statement?"
] | [
false
] | null | [
"Not really any truth to this statement. London is the perfect example to demonstrate this. London burned completely to the ground in 1666, but yet the road layout in the center of the city is over a thousand years old. In the days after the fire there were lots of plans to completely redo the road system, and the ... | [
"Actually I was talking about the City of London, which lies within the city Greater London. They have their own mayor, governing bodies, and police force separate from Greater London. They control the Port of London's health authority which includes London Heathrow airport.",
"I wouldn't call that completely mea... | [
"I'm guessing you mean the City of Westminister? While this is legally an independent city, in reality those laws have no meaning. It is just part of the quaint idiosyncrasies that is English Law. England has no written constitution, but rather a thousand years of legal case law, acts of parliament, traditions and ... |
[
"How does oxygen go from lungs into blood? Could you explain in details and simply?"
] | [
false
] | Thank you in advance | [
"Think of it as a wall with 1-way valves in the shape of oxygen (into the bloodstream) and CO2 (out of the bloodstream)",
"There's no directed \"valve\". Diffusion there is just a matter of the different concentrations on both sides."
] | [
"It's not an overly complicated system really",
"You breathe in, air enters your lungs, eventually reaching a part of the lungs called the alveoli. The alveoli are 'fluffy', so as to have a high surface area, and surrounded by capillaries (small blood vessels). ",
"The barrier between the alveoli and surroundin... | [
"Can you oxygenate a person (or mammal that uses lungs) in any other way besides the lungs?",
"What I’m getting at is, how do babies in the womb breath or get their oxygen from via the umbilical cord?"
] |
[
"Is there adequate evidence, beyond the anecdotal, to suggest that the internet has lowered attention spans, memory and/or patience?"
] | [
false
] | null | [
"You may be thinking of ",
"this Science article",
", which reports:",
"This is preliminary evidence that when people expect information to remain continuously available (such as we expect with Internet access), they are more likely to remember where to find it than to remember the details of the item. One co... | [
"One could certainly be smart with a short attention span, however."
] | [
"One could certainly be smart with a short attention span, however."
] |
[
"In terrestrial contexts, cooler flames are red while hotter flames are white/blue. How can it be that stars also exhibit this characteristic?"
] | [
false
] | I've heard many times that cool flames are red/orange while hotter flames are white/blue. I've also heard that the difference in colour between red dwarf stars and white dwarf stars is caused by difference in temperature. How can it be that a star - which is presumably much hotter than, say, burning alcohol vapours in a flambé - is cool enough to still be red for the same reason? Do the color "thresholds" change depending on the condition (vacuum of space vs. sea level on Earth)? Or maybe red dwarf stars really are that cool? | [
"Red dwarf stars--- or at least their surfaces--- really are that cool. "
] | [
"The sun looks orange yellow ... because it is made up of mostly superheated hydrogen ... releasing a single wave length of light, which is orange-yellow. ",
"Are you sure about this? ",
"Here",
" is the solar spectrum. It is nearly a black body spectrum (T ~ 5500 K). The biggest deviation is at ",
"500 ... | [
"The sun looks orange yellow ... because it is made up of mostly superheated hydrogen ... releasing a single wave length of light, which is orange-yellow. ",
"Are you sure about this? ",
"Here",
" is the solar spectrum. It is nearly a black body spectrum (T ~ 5500 K). The biggest deviation is at ",
"500 ... |
[
"What happens when a particle loses all energy? Can you drop below the ground state? [physics]"
] | [
false
] | null | [
"The ground state is, by definition, the lowest energy state a particle can be in. If it was possible to drop lower then that lower state would ",
" the ground state. ",
"Depending on the situation, the ground state may be zero energy, or some small finite nonzero energy."
] | [
"I read somewhere that even in ground state, particles still maintain some kinetic energy, is it possible to lose ALL energy?"
] | [
"That was what my last statement was. There are some cases where the lowest possible energy (the ground state) is not zero. But by definition those situations it can not lose it, it is the lowest possible, it can not lose it.",
"Other situations, it can lose all energy. The ground state of a particle is defined b... |
[
"What can we use bronze for today and why?"
] | [
false
] | I was wondering what we use bronze for today and the reason for it. I cant seem to find a reason for using bronze in industrial and non-industrial purposes. | [
"Bronze type alloys are often used in places where you want low friction with steel parts. The most common example are oil infused bronze bushings for rotating parts. They are cheaper and take less space than roller bearings. "
] | [
"The propellers on ships are commonly made from a bronze alloy. Mainly because it is very resistant to corrosion and has good machinability."
] | [
"The most common example are oil infused bronze bushings for rotating parts.",
"To elaborate, this type of bushing is a porous cylinder sintered from powder, then filled with a wax/oil/mix. Capillary action and heat draw the lubricant to the surface, but surface tension keeps it from actually going anywhere. Wa... |
[
"Does Earth tilt/seasons affect the amount of moonlight we get like it does with the sun?"
] | [
false
] | Like… do we get more hours of moonlight per day in the summer vs the winter? Or maybe it's the other way around? Or does it not matter and we always get the same amount? | [
"No.",
"Seasons exist because the axis of rotation of the earth isn't \"vertical\" to the earth's orbit around the sun, and the axis doesn't really change. So for large parts of the orbit, the northern hemisphere points slightly away from the sun, and gets less sunlight. Half a year later, the sun has moved \"aro... | [
"So you're saying the moon is in the sky for the same amount of time each day/night no matter where you are on the planet?"
] | [
"I think there is a big misunderstanding between you two. Although viscence is correct, i think the OP was asking for each phase. In that case, the moon would be indeed at different places over the year. ",
"For example, the full moon on the northern hemisphere will be very low over the horizon in june/july, beca... |
[
"Is absolute motionlessness impossible in the universe?"
] | [
false
] | Let's say I get in a spacecraft and travel to the area between our galaxy and Andromeda, then just stop. As I understand it the galaxies would still be moving away from me due to the expansion of space, and relatively speaking I'm also moving away from the galaxies due to the expansion of space. Does mean that it's impossible to be perfectly motionless since everything is moving relative to each other? | [
"You are motionless in your rest frame. You are moving in another equally valid frame of reference. There is no absolute frame of rest.",
"Consider two objects that are not at rest relative to another. You can either be in a reference frame in which one is moving, the other is moving, or both are moving."
] | [
"This question is actually bugging me a bit, let me try and explain my issue.",
"Consider two objects that are not at rest relative to another. You can either be in a reference frame in which one is moving, the other is moving, or both are moving.",
"I suppose you know about the ",
"twin paradox",
" , so if... | [
"If you have two twins moving relative to each other, they do not necessarily have to agree on the sequence of events. Simultaneity is not guaranteed between reference frames, and this is one of the more confusing aspects of special relativity (look up the ladder paradox, for example). So in this case, one could se... |
[
"How do accents form?"
] | [
false
] | I was talking to my dad about this today. How does an accent come about, and why do they exist? I was thinking specifically about somewhere like Australia or America, where it was colonised by British settlers. Thanks in advance! | [
"I would like to add a follow up question:",
"Are accents just precursors to new languages? If Donald Trump built a wall around the former Confederate States, would the southern accent eventually become another language in a few centuries?"
] | [
"While groups of people who share an accent speak alike, no two individuals speak exactly alike. There's natural variation. When a language community is isolated from other speakers of that language, it is free from reinforcement from outside and those variations are allowed to evolve independently and gain their o... | [
"If there was no interaction ",
" (no migration, no media, no internet) between the two regions, then ultimately, the languages spoken by those inside the wall and those outside would diverge, but not because the ",
" are different, not the ",
". If something new were invented that was visible from both insid... |
[
"Why do particles with no mass have to travel so fast?"
] | [
false
] | null | [
"Physics"
] | [
"Physics"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"guidelines",
"Please see our ",
"list of related subreddits",
" for other options for your question.",
"If you disagree with this decision, please send a ",
"message to the moderators."
] |
[
"Psychologists and/or psychiatrists, what is the difference between dissociative identity disorder and alter ego?"
] | [
false
] | null | [
"An alter ego has no psychological definition, and as a result refers to many things. Many of those things are engaged in willingly by the person, such as:",
"A second family",
"A pseudonym",
"Superhero civilian personas",
"Dissociative identity disorder involves an individual possessing an alter ego, but i... | [
"So basically it's Sasha Baron Cohen/Ali G. vs. DR. Jekyll and Mr. Hyde?"
] | [
"Yeah, kinda. As said an alter-ego is more of a chosen identity, Dissociative personality disorder is what used to be called multiple personality disorder - it's more of a fragmentation of personality that the suffer switches between without conscious choice. Someone playing the role of their alter ego know that it... |
[
"Why does a spine have protrusions on it? What causes this and how are they evolutionarily useful?"
] | [
false
] | null | [
"The ",
" that protrude from each vertebra in the spine have two main purposes. The longer ones are attachment points for ligaments and muscles, giving muscles more area to attach, and also acting like long levers to help the muscles bend, straighten, and rotate the spine. There are also smaller protrusions, call... | [
"Or spikes weren't sexy, so non-spikers got more and out reproduced the spikes."
] | [
"Or spikes weren't sexy, so non-spikers got more and out reproduced the spikes."
] |
[
"Why can I hear a snapping/popping sound when scuba diving or snorkeling near coral reefs? What makes that noise?"
] | [
false
] | My best guess is that it is small organisms popping in and out of coral. I am curious what the real answer is. Can anyone help me? | [
"Underwater organisms are loud! There are lots of crustaceans and fish making various noises down there cracking shells with their claws, crunching hard shelled organisms with their teeth and communicating to each other via all manner of sound producing organs..."
] | [
"Also, the sounds carry differently in water."
] | [
"There is a type of Crustation called a Mantis Shrimp. It kills its prey by smashing their Shells in and eating them. (Unless they are the the Spearing kind). ",
"And the Pistol Shrimp can also be an explanation. \nMantis is more likely though. "
] |
[
"Question on Time Dilation"
] | [
false
] | So I finally read up on special relativity and I'm a bit confused right now. Using the analogy of two spaceships, if one space ship moves at 0.9c relative to the other, the moving one would have its time slowed down from the reference of the second. However, because velocity is relative, the second spaceship would also be observed to have a slower time relative to the first. Here's where my confusion comes in. So when both spaceships suddenly travelled at equal velocity such that both are of zero relative velocity to one another and thus of equal reference, which one would have the slowed time? | [
"You've discovered ",
"the twin paradox",
".",
"The answer is that you can't have the spaceships \"suddenly\" be at rest with each other. Either one or both must undergo acceleration. In the case of one spaceship accelerating and becoming at rest with the other, the accelerating spaceship has its time dilated... | [
"I see the light now. Thanks!"
] | [
"He understands all that, you completely missed the point of his question."
] |
[
"How do Feynman Diagrams work?"
] | [
false
] | [deleted] | [
"Not a very detailed question. To give a simplified answer, then:",
"When you do the math of quantum mechanics (in this case the part known as quantum field theory/quantum electrodynamics), you end up with equations you can't solve exactly, mathematically. ",
"But there's an approximation method, known as ",
... | [
"They are also used in polymer physics to get a better picture of how polymers orient themselves in space. ",
"See for example figure 7"
] | [
"If you say so :) ",
"On a cursory reading I recognize the general formalism, but can't say I have the foggiest idea about what they're doing with it, there."
] |
[
"Theoretically, how small can a nuclear warhead be made?"
] | [
false
] | null | [
"It's called the ",
"Special Atomic Demolition Munition",
". But the W54 warhead is possibly the smallest nuclear device capable of being fired from a weapon with a yield dial-able between 10 tons and 1 kiloton."
] | [
"Small enough to fit in a backpack and be carried by one man. Since the minimum size for a non-pressurized chain reaction that just melts seems to be about the size of a baseball implosion with neutron reflective material seems to make it possible to do with even smaller quantities than that, with a powerful enough... | [
"Thanks. I am amazed at the information the internet is making readily available."
] |
[
"If terrestrial plants get the majority of their mass from the carbon dioxide in the air, where do aquatic plants get their mass from?"
] | [
false
] | null | [
"Carbon dioxide in the water. Water can have gasses dissolved in it, so pretty much the same processes happen in water as in air. Plants suck dissolved CO2 out of the water, break it apart and react it with water, then spit out excess O2. Fish and plankton absorb this oxygen, then expel CO2."
] | [
"Are you thinking of algal blooms?",
"These usually occur when nutrients (often fertilizer runoff from farming) get into a water supply and give algae the nutrients they need to rapidly proliferate (called ",
"eutrophication",
"). This results in reduced dissolved oxygen for a number of reasons, but essential... | [
"Aren't there water plants that absorb O2? I thought I read something that they could be dangerous if they grow too much in numbers for the animals living there."
] |
[
"Will two engines with the same HP but with different engine displacement consume an equal amount of fuel?"
] | [
false
] | [deleted] | [
"If one engine is a 2.0 and the other is a 4.0, they are by definition not the same type (unless by type you mean \"gasoline-powered.\")",
"Broadly speaking, the 4 liter engine will have higher torque output at a lower RPM range, while the 2 liter engine will have a horsepower advantage at high RPM (a rev speed t... | [
"I'm not an engineer, so someone feel free to jump in, but this is my take on it...",
"The efficiency of the engine goes well beyond the displacement, and what you're asking is purely about efficiency. ",
"Gasoline releases 19,000 BTU's of energy per pound, or about 112,480 per gallon, and one horsepower is 254... | [
"Upvote for a complete and clear answer, but as a physicist I am compelled to point out that \"ft/lb\" is not a torque, it is an inverse spring constant (a measure of spring softness). You want \"ft-lb\", or (even better) \"Nm\"."
] |
[
"Do 'normal' cats have the same wrinkles that sphinx cats have under their fur?"
] | [
false
] | Does this apply to other mammals with fur? Also, is there an evolutionary advantage to the large amount of wrinkles sphinx cats have? | [
"Yes, sphinx cats are just hairless cats and I don't think there's a real advantage to it.\nThey get cold very quickly so owning one they must always have clothing, they also have no hair to groom so they get stinky pretty easy and needs baths every 2-3 days.\nSource: I'm a vet nurse trainee, just had one come in t... | [
"Note: Sphynx cats were developed through selective breeding in the 1960s. This artificial selection means the question of \"evolutionary advantage\" doesn't really come into play, unless you consider it an advantage in being selected by humans to breed.",
"As for other mammals, here are pictures of some examples... | [
"The advantage to having the extra skin(that ends up in wrinkles) is partially in stretching-gives them rooms to expend when running, and in fighting it lets them twist around under their skin and escape.\nBut these apply to all cats not just hairless ones. "
] |
[
"How did Houston communicate with the astronauts on the moon?"
] | [
false
] | null | [
"USB",
". But not the adapter type. Radio waves - the general method of communication in space for basically everything (laser links are a very recent development).",
"By changing the amplitude or (better) the frequency of the radio waves you emit many times per second you can transmit information."
] | [
"The carriers were neither amplitude nor (except TV) frequency modulated by the Apollo Unified S-Band transceivers. The vast majority of their communication utilized Phase Modulation."
] | [
"Like those times Ensign Kim got caught in the transporter?"
] |
[
"In a theorized multiverse, how are \"universes\" separated from one other and can they influence each other?"
] | [
false
] | null | [
"Which 'multiverse' are you talking about?",
"One view of the multiverse is that the big bang was a point origin of our universe, but there may be other point origins far removed from ours. This is the ",
" multiverse. These universes are separated from each other by immense distances. They can never influen... | [
"I can answer from a physics/mathematics perspective.",
"Our perspective is limited to 3 dimensional space. In a multiverse philosophy, there is basically a 4th spatial dimension. So imagine that all 3 of our dimensions were squashed flat into 2 dimensions. There would other universes above and below us that are... | [
"Like kburger said, there is no way to know since we would have no contact or perception of the extra dimension. If large forces were capable of acting in the extra dimension we could possibly notice physics abnormalities in our own universe. However, there is still so much that we don't understand about physics,... |
[
"Using two video cameras, getting two different angles of a flying object what could you prove?"
] | [
false
] | Given a flying object, of unknown size, speed and distance, being filmed by two stationary cameras, with a known distance between the cameras and hopefully known angles that the camera are set at what could you prove regarding the flying object? I dont really want to talk specifically about the case below, but more in a general fashion. Lets say I was out in Nevada at Area 51 (its just convenient for the description). Me and my buddy TinFoil have the exact same cameras (Red One) and we have set up on two different points of the same height etc and we have measured the angles of where our cameras are pointed. Out of nowhere something appears, we film, and it goes away. THen we sit down with our footage, we sync it up 100% good, and we start doing the math. What could we for sure prove about the object? Since the distance to the object, the objects size, and the objects speed are all unknown variables, and since the object is in the sky, during day time, making it more difficult to find an anchor point to fix it too. How much more could we prove with more cameras at different focal points. This question was fully inspired by this reddit post I read today [ ] | [
"With the angle and knowledge of the camera lenses and FoV we can determine the precise location of the object with triangulation. We can also determine the cross-section from both angles, and given some maneuvering of the craft, an accurate measure of its shape. Since we can determine its location we can also dete... | [
"Careful, though. Don't convince yourself your calculations are more precise than they are. From a theoretical standpoint, any two cameras at any two places (well, almost...) shooting the same object will give you this information. Thus, stereoscopic cameras placed inches apart would suffice. In the real world, the... | [
"I would love to try and read up on the math behind it. \nAny links to suitable material?"
] |
[
"Does tire pressure change when they are in motion (rotational)?"
] | [
false
] | I know that there is only one point of the tire that touches the ground at once and it applies a static force to the ground forcing the vehicle forward, but does this force cause a compression (significant or insignificant) to the tire itself. If it does, how much? Thank you! | [
"The ",
"weight of the car will cause a miniscule pressure change in the tire",
" (as compared with an unmounted tire), but typical acceleration and velocity will not cause any further changes.",
"The force that moves the car forward is a result of torque at the axles. This torque is transmitted through the ... | [
"Unless of course you're talking about a ",
"Top Fuel Dragster",
", but that's probably not what the op is asking."
] | [
"Friction generating heat. Yes."
] |
[
"What would happen to the stiffness of a spring if you would cut it in to two equal pieces?"
] | [
false
] | null | [
"The spring constant of a spring is inversely proportional to the length. ",
"Look up “Hooke’s law” and you'll find a bunch of info."
] | [
"For a bit more detail, the stiffness k can be calculated like so:",
"k = G d^4 / 8 D^3 N\n",
"where",
"k = spring stiffness",
"G = shear modulus of the material",
"d = diameter of wire",
"D = diameter of spring",
"N = number of turns",
"Source",
"Chopping the spring in half is basically like cutt... | [
"If I am thinking about this right, this means the total force a spring exerts at a specific percentage length change doesn't depend on the number of turns, right? Since the absolute length change per relative length change is proportional to the number of turns, and the spring constant is inverse with the number o... |
[
"Is there any evidence linking the period of heavy nuclear testing (1940s to 1970s?) to increased rates of cancer, either locally, nationally, or globally?"
] | [
false
] | null | [
"Yup, Castle Bravo. Was supposed to be about 6 megatons, instead it was 15. The problem was that Lithium-7 (which makes up most natural Lithium) is basically inert at low to medium neutron energy levels, the sorts of neutron energies which come out of fission reactors, for example, and were used for studying the pr... | [
"There arę, at least locally. After one of tests went wrong (castle bravo? Might be wrong but iirc that one. Had to do with additional fuel breeding during detonation, pushing the yield from expected few megatons to over 15mt) local population was subjected to fallout. That has caused very high cancer rates later."... | [
"It's been looked at in ",
"a couple of dozen studies",
", most focusing on high-risk areas like the Marshall Islands and the Semipalatinsk Nuclear Testing Site in Kazakstan but with a few looking more generally.",
"A number of studies found a slight increase in leukemias in the US:",
"The entire United Sta... |
[
"How come Nuclear Pasta is the strongest material on the universe?"
] | [
false
] | null | [
"Yeah, they'd explode. They only exist because of the enormous pressure inside the star. Take them out and they decompress and produce regular nuclei like you find on earth."
] | [
"Basically, it's because nuclear pasta is so dense. Nuclear pasta is nearly as dense as atomic nuclei- in a neutron star matter reaches densities a hundred trillion times anything on earth.",
"This results in really extreme properties. Denser things will general be stiffer (which is what's meant by \"strongest\" ... | [
"To be clear, if you somehow could bring these materials to the earth, they probably wouldn't maintain their properties right? They would fall into lower energy states where they were less dense?"
] |
[
"What is the largest known non-aquatic arthropod?"
] | [
false
] | [deleted] | [
"The largest organisms",
": \"The coconut crab (Birgus latro), also a crustacean, is the largest land arthropod and the largest land invertebrate, up to 40 cm (1.3 ft) long and weighing up to 4 kg (8.8 lb) on average. Its legs may span 1 m (3 ft).\"",
" \"Was either the eurypterid (sea scorpion) Jaekelopterus o... | [
"According to the internet, among currently living arthropods, it's the ",
"coconut crab",
". If we allow for extinct species, the largest known would be from the genus ",
", related to centipedes and milipedes.",
"Edit: and now I feel silly, posting 2 minutes after someone gave the same answers. We need to... | [
"haha I feel the same way!"
] |
[
"Why aren't gravitational batteries viable on large scale?"
] | [
false
] | [deleted] | [
"This is an excellent idea and is therefore already used in practice at many places. It is called pumped-storage hydroelectricity. Thereby, water is pumped up into a reservoir at higher elevation with electric pumps. If needed, the water is used to generate electric power using turbines. \nAs you can pump hundreds ... | [
"https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity"
] | [
"Just as a scale thing: the total installed \"battery\" capacity in TWh, of which the vast majority is PSH, along with the maximum power generation from PSH, is about 0.8% of world annual energy consumption/average power generation. ",
"We don't have a good way to store energy on a large scale. PSH is the best ... |
[
"Why do microwaves damage circuitry?"
] | [
false
] | null | [
"Microwaves, or any light for that matter, are oscillating EM fields. In the case of MW its on the same size order of most of these objects so the fields couple very well.",
"These fields then induce a current which then proceeds to short or melt various parts of circuits."
] | [
"The metal inside your electronics acts as an antenna for the microwaves - the induced current (which is probably on the order of hundreds of watts) shorts and melts various parts of the circuitry."
] | [
"Came here to say this... But then I started to explain how dielectric heating works, got confused, and had to lay down for a few hours. You left it where you should have."
] |
[
"Do females and males have different amounts of rods and cones in their eyes?"
] | [
false
] | Do females and males have different amounts of rods and cones in their eyes? I have heard it as a back up to a theory that women and men see colour differently, but I don't remember there being any differences in anatomy from biology class. | [
"There is an important gender effect on cones - the L/M wavelength cones use a photopigment that relies on genes located on the X chromosome. when that gene is defective, you generally have red-green colorblindness. since women have two X chromosome, they are far less likely to be r-g colorblind, since they'd need ... | [
"The genes for color blindness are on the X chromosome, not the Y. People with XX chromosomes (females) almost always have another gene to correct this. People with XY chromosomes (males) do not have an extra X chromosome to correct the color blind genes on the Y, so they end up color blind. The genes for hemophi... | [
"Not sure about the cones thing, but men have a higher chance of being color blind because certain types of color blindness are sex-linked recessive on the Y chromosome. Most bio females (there are some rare exceptions such as Swyer Syndrome) dont have a Y chromosome so they cannot possibly express the gene for col... |
[
"Since space isn't a complete vacuum does light ever actually travel at the speed of light?"
] | [
false
] | null | [
"No, but it travels close. Due to free electrons in the interstellar medium, light waves undergo ",
"dispersion",
". Dispersion is the same optical effect that you see when white light goes through a prism and splits into different colors of the rainbow. In practice, dispersion only affects radio waves measurab... | [
"Good question. Yep, it'll speed back up, just like if you have optical light going through a bunch of prisms with different refractive indices and it goes from one to another with the right properties. You can also think about this in terms of the DM being the integral of the electron density along the path. So, y... | [
"Would photons 'speed up' when moving from an area with a certain DM to an area with a lower DM? Or would they retain the same speed, but it would be comparatively lower to the c number for the current, lower, DM?"
] |
[
"Do the lattice constants of NaCl and KCl change when water is added, if so do these changes remain when the water is removed or do the lattice constants return to their original lengths?"
] | [
false
] | [deleted] | [
"Do you mean when you dissolve them in water? ",
"When a salt dissoves in water, the Na is attracted to the negative oxygen while Cl is attracted to the hydrogen in turn splitting the salt into Na+ and Cl-. Because of this the salt no longer has a crystalline structure so it doesn't have lattice constant.",
"ed... | [
"The water would pull apart as many NaCl molecules as it can. The lattice would remain unchanged. It will either exist in crystalline form or as a solution."
] | [
"The water would pull apart as many NaCl molecules as it can. The lattice would remain unchanged. It will either exist in crystalline form or as a solution."
] |
[
"Would a biological radio be possible?"
] | [
false
] | I thought about the amazing senses we have and wondered if it would be possible for a sufficiently advanced race to communicate telepathically via radio waves, also i'm going to split this into two parts for ease of understanding. Is it possible to have a biological radio transmitter/reciever I.E a radio organ at all? If possible would a average size mammal be able to produce enough power to transmit over meaningful distances, say 10-100 meters. In essence, if both of these are true, telepathic communication would be possible right? | [
"Well, it surely wouldn't be impossible. There are animals featuring ",
"electric organs",
". Also, it seems that some of them can already communicate modulating weak electric fields (",
"see here",
" for example), which is probably the closes thing we have to radiocommunicating animals. To do that long-dis... | [
"Considering how simple a ",
"crystal radio",
" receiver is, it doesn't seem too implausible that somehow there could be a \"receiving\" organ, even if it were very inefficient (but maybe still effective for short distances). Just need an organic diode, mainly, and maybe something in the brain to interpret the ... | [
"This seems implausible, magnetic field drop-off rates would mean unless one organisms sensing organ was directly adjacent to the other organisms transmitting organ, it would be phenomenally difficult to get a useful signal. Additionally, this totally glosses over the difficulty of organically building such a power... |
[
"Are there any residential scale carbon capture technologies available?"
] | [
false
] | I’m considering adding an non-grid tie solar system to my home. As solar is somewhat variable in energy production the system would need to be sized for poor production times of year/days. Are there any electrically based carbon capture technologies that could be run with excess electricity production? I’ve seen some diy solutions but by the time I’ve purchased and had shipped the needed chemicals then disposed of them I’ll have spent all the carbon I would have captured. | [
"If you want to personally remove some carbon from the air, grow corn, sorghum, or some other C4 crop, make charcoal from the inedible parts, and bury the charcoal in your garden. Charcoal degrades very slowly in the soil, so the carbon it contains will stay out of the air for a long time, and the internal surface ... | [
"To literally sequester carbon, the suggestions you've gotten about trees and biochar are good options. As far as beneficial uses for excess electricity towards reducing climate change, assuming the grid in your region still uses fossil fuels, one of the best things you can do is connect to the grid and send your ... | [
"Biochar",
" might be one practical DIY method of carbon capture and storage. ",
"But take a step back and consider the objective - to reduce climate change. Perhaps you would achieve a larger reduction by helping other people install solar systems if you are becoming skilled at this activity. ",
"You can st... |
[
"What is the speed of time?"
] | [
false
] | null | [
"1 second per second."
] | [
"Speed is a measurement relative to time. ",
"You can't measure something with relativity to itself. "
] | [
"Can you clarify/expand on the question?"
] |
[
"Could a brown dwarf sustain a life-bearing planet/moon and if so what would be the goldilocks zone?"
] | [
false
] | I'm curious about Arthur C. Clarke's idea of Jupiter becoming a brown dwarf and it's Galilean moons becoming habitable (I think this was from the novel 2010?). I wondered how realistic that was, or if they would be too close. Also for bonus points: what do we call a body that orbits a brown dwarf - is it a planet or a moon? | [
"The problem with brown dwarfs is that, unlike stars, they don't provide a constant source of light, but rather one that diminishes greatly over time.",
"When first formed, a brown dwarf is pretty hot and easily rivals the brightness of a small star. However, it quickly burns through its deuterium reserves (and p... | [
"Most likely a dwarf planet",
"The planet / dwarf planet distinction is based on whether the object has cleared its orbit, not what kind of star it orbits."
] | [
"I don't know, I haven't read the book OP mentioned. Presumably a hyper-advanced spacefairing civilization dragged a bunch of hydrogen in from nearby stars or something like that. "
] |
[
"Can we pull a reflected image off a \"nonreflective\" surface?"
] | [
false
] | Can we pull a reflected image off a "nonreflective" surface? Reflectiveness is relative. A dirty mirror could be called reflective. A cracked or distorted mirror too. But how about white sheet of paper? Or a rock? It may not be an image that our eye or mind can appreciate, but maybe we could run the reflected light through a noise filtering algorithm. So I guess the real question is, how good are our reflected light image extraction algorithms? What's the limit on extractability? | [
"Yes, if you're willing to use a specialized time of flight camera and pulsed light source.",
"Here's a ",
"cute short video that explains and demonstrates",
". You can see the latest work from those researchers on ",
"their webpage",
"."
] | [
"there was no technical explanation of this, so i'm going to think out loud here -- i'd be interested to hear your ideas about this!",
"this is surprisingly similar to the process of creating a hologram, except in this case the recording medium might instead be a scanning photodiode of some kind.",
"from what i... | [
"If you can run a calibration of a known point source of light on the surface you want to image from, you can do optical signal processing on the new reflection. For instance, as far back as the 1960's they could recover a clear image from a camera that was set out of focus. This was primarily developed by the mili... |
[
"How small can a radio receiver get?"
] | [
false
] | In addition, does the size of the receiver have any bearing on the number of frequencies it can distinguish? | [
"In terms of the antenna that must be within 1/4-1/2 of the wavelength of light in order to efficiently receive/emit.",
"That being said there are fractal antennas that fold upon themselves to create a long length in a short space, as well as short lengths for multi frequency reception."
] | [
"Must it be 1/4 or 1/2?",
"Can it be multiples of these ratios, i.e., 1/8, 1/16 of wavelength?"
] | [
"usually its a value between 1/4 and 1/2 of the wavelength. Those are just the values that allow the electric field to couple efficiently to the antenna. Smaller and the light wont couple at all, larger and the light will couple in multiple places and create interference. "
] |
[
"How long after the Big Bang did the first supernovas happen?"
] | [
false
] | [deleted] | [
"Don't forget, in astronomical terms, millions of years later ",
" \"shortly\" :) The first stars are thought to have formed roughly 100 millon years after the Big Bang. These would most likely have been incredibly massive, a few hundred times or even a thousand times more massive than the Sun. Stars this massive... | [
"Right. Keep in mind this only applies on dim red stars, not read stars in general. Any red dwarf that has ever formed is still in existance, except the ones, which were involved in few star collisions. No red dwarf has died by age so far. "
] | [
"The more massive a star is, the shorter its lifespan - a dim red star, less massive than the Sun, will have a lifetime longer than the present age of the Universe",
"Does this mean there are no dim red stars that have \"died\" yet?"
] |
[
"Question about the future of human evolution"
] | [
false
] | [deleted] | [
"For speciation to occur, two populations of a single species must be physically separated for a very long time. This is not likely to occur in humans."
] | [
"I'm not really sure I understand the question. Are you asking me why I don't think humans will fragment into separate, non-interbreeding populations?"
] | [
"I'm not really sure I understand the question. Are you asking me why I don't think humans will fragment into separate, non-interbreeding populations?"
] |
[
"What actually is the dial up internet noise?"
] | [
false
] | What actually is the dial up internet noise that’s instantly recognisable? There’s a couple of noises that sound like key presses but there are a number of others that have no comparatives. What is it? Edit: thanks so much for the gold. | [
"Everything you need to know about the acoustic modem handshake can be found here on this map: ",
"https://oona.windytan.com/posters/dialup-final.png",
"Then you can listen to the actual handshake and follow along:\n",
"https://www.youtube.com/watch?v=abapFJN6glo",
"Yes, this is what network engineers still... | [
"Sometimes I miss that sound. For years it meant I was about to talk to or play games with good friends."
] | [
"That first image you linked is amazing. Thank you."
] |
[
"Do larger animals have a bigger chance to get cancer?"
] | [
false
] | Larger animals have more cells, and since cancer is a defect cell, more cells should mean a higher chance at cancer, right? | [
"In general, larger animals are not more prone to getting cancer, and this is known as ",
"Peto's Paradox",
", after Richard Peto:",
"These may be nicely illustrated by a comparison of mice and men: A man has 1000 times as many cells as a mouse (although the ratio of our epithelial stem-cell numbers is not kn... | [
"No. Elephants for example are massive but have more oncogenes and cancer suppressor genes do they are less prone but a large margin. Similarly many sharks don’t get cancer as well bc of suppression genes as well"
] | [
"Sharks ",
"do get cancer",
" and that myth has to do die."
] |
[
"Knowing that we are all stardust is there a way to find out from how many is, approximately, each person made?"
] | [
false
] | null | [
"I think on average, each human is made from roughly 75 kg of stardust. Depends on the weight of the person.",
"No, honestly, how do you define stardust? We do probably consist entirely out of stardust (depending on your definition).",
"You could say that stardust is everything that once was in a star. That mea... | [
"But how many stars? How many stars exploded resulting in the cloud of dust that our solar system aggregated from? Can that be measured?"
] | [
"Sorry, I had misread your question. For this I can not really give an answer. Most of your atoms will probably come from a single star, but of course you will have some that are from completely different ones. How the ratio between those two is would depend on how far out a supernova distributes the atoms of its s... |
[
"Why at airports can they complete the detection for drugs quickly and accurately, and yet medical results and such can take weeks for results?"
] | [
false
] | null | [
"For scanners that you walk through, they search for an isotope of nitrogen (for example) because many explosives contain a lot of it, and if the particular isotope is out of balance with what should be present, it's a good bet a follow up is warranted. Certain nuclides can be detected easily because even tiny amo... | [
"At airports, they often use Biosensors and other sender's that detect drugs and explosives based off of their residue. ",
"They usually use ion mobility chromatography coupled with MS to detect different substances. ",
"it's described here",
" and the machines where they put in the fabric they used to wipe o... | [
"At airports, they often use Biosensors and other sender's that detect drugs and explosives based off of their residue. ",
"They usually use ion mobility chromatography coupled with MS to detect different substances. ",
"it's described here",
" and the machines where they put in the fabric they used to wipe o... |
[
"What is the trade-off that requires astronauts to be able to withstand several Gs during launch?"
] | [
false
] | I know about escape velocity, but in my mind it doesn't help much in knowing about the acceleration during launch, especially why the acceleration couldn't be made less. As a side question, how much as far as Gs during launch does it matter if we are headed to LEO or headed to the moon or beyond? | [
"It's a matter of efficiency. Consider the following thought experiment: What if you have a rocket that can just barely accelerate under gravity (it provides enough thrust to fight gravity, and just a little more)? After 10 seconds, it has only picked up a few m/s of velocity, but it has spent 10 seconds worth of ... | [
"If you want a great intuitive understanding of the tradeoffs, download ",
"Kerbal Space Program",
" and try to reach orbit with the least fuel possible.",
"The basic answer to your question about tradeoffs though is: if acceleration is too low, you'll spend most of your fuel essentially hovering in place; if... | [
"Rockets launch straight up and slowly turn over until they are parallel to the ground. Most of the fuel is used while the rocket is parallel to the ground so it can build up enough speed to reach orbital velocity.",
"A low thrust rocket would need to hover the entire way into space so it doesn't fall back to ear... |
[
"Does the brain have or require a human equivalent of RAM?"
] | [
false
] | [deleted] | [
"Computing analogies are often dangerous when applied to the brain. The RAM/Hard drive one is particularly bad.",
"You see, one of the better ways to actually make a computational analogy is to remove the hard drive from the computer altogether. If we take a very simple computer, where RAM directly interacts with... | [
"RAM is a particularly good analogy because if the brain loses power it tends to lose all its data :)"
] | [
"Holy shit that was a great answer!"
] |
[
"What happens when an object enters Earth's atmosphere traveling faster than its terminal velocity?"
] | [
false
] | As a side question, what would happen if something enters another planets atmosphere, say, Jupiter, faster than it's relative terminal velocity? | [
"What happens when an object enters Earth's atmosphere traveling faster than its terminal velocity?",
"Drag slows it down toward its terminal velocity.",
"As a side question, what would happen if something enters another planets atmosphere, say, Jupiter, faster than it's relative terminal velocity?",
"Same th... | [
"Terminal velocity is the speed at which gravity and atmospheric friction cancel each other out. So if an object enters the atmosphere faster then terminal velocity, earths gravity will not be able to speed up the object enough to prevent the atmosphere from slowing it down. As a result, the object would lose speed... | [
"To add to the other answer, terminal velocity itself depends on altitude and projectile orientation. As altitude increases, air density decreases and terminal velocity increases, towards an extremely high value in outer space much faster than any natural object. Therefore any object that has come from outer space ... |
[
"Does putting on sound-canceling headphones decrease the amount of noise my ears, or add it it?"
] | [
false
] | If I put in sound-canceling headphones, is it adding noise to my ears, like if I had 110 units of sound (forgive my lack of knowledge on the subject) and I put on sound cancelled, and I still taking in 110 units, just quieter? Interpreted quieter? Or is the music I then put on making it 170 or so? (again, it's just for understanding) | [
"The noise cancelling headphones detect the ambient sound and then emit the exact opposite of that waveform causing ",
"destructive interference",
"#Mechanism). This reduces the movement of the air in your ear and so decreases the noise, I hope that's the right question I've answered, it was a little confusing.... | [
"It reduces the intensity level (the noise would be 0 if it were perfectly opposite). You can't just add the intensity of the two waves, because they are out of phase."
] | [
"Oh I understand that, I was wondering if that counter-noise adds to the total noise, hurting my ears, or cancel the noise and all potential damage it could do. Like if I stood next to a jet engine at, let's say 200 decibels, would the counter noise at 200 make the total 400 and potentially damage my ears, or do th... |
[
"How do we know that dark matter interacts weakly with other matter. Isn't it possible that it doesn't interact at all?"
] | [
false
] | Isn't it possible that it only interacts gravitationally? | [
"Yes, it's absolutely possible. That's a terrifying prospect that people obviously avoid talking about, but it's there.",
"In most reasonable scenarios for dark matter and grand unification though, there's hardly any way of avoiding some very weak interaction with SM particles. A completely non-interacting DM is ... | [
"If dark matter interacts only via gravity, it will be extremely difficult to learn more about it. For example we would have no hope of detecting or producing individual dark matter particles in the foreseeable future, because gravity is an extremely weak force."
] | [
"Why is it terrifying?"
] |
[
"There are several \"health products\" becoming increasingly popular such as the ionic foot detoxer, water ionizer, nanosilver water, and ozone generators. Could these \"health products\" actually be harmful?"
] | [
false
] | The pamphlets that I have read for these products describe how they can make you healthy. For example, read the very scientific-sounding explanation of how the ionic foot detoxer works, I am obviously skeptical of the validity of their claims but I do not know enough (Chemistry, Biology, ect.) to understand why these products wouldn’t have the stated health benefits. Can anyone ELI5? Even more important, can these products be harmful to a person’s health? | [
"Yep for sure they have the potential to be harmful! There is tons of research that is going into this currently! Though right now I think they're working on the physiological effects of fish gills (and therefore certain ion pumps that are critical to our respiratory and circulatory functions similar in humans). ",... | [
"this was a quick search and i didn't look into the sources too closely (it's late, i wanted to at least give you a starting point), so i cannot speak to their veracity, however the claims of most of these products are wholly unsubstantiated through research and as you suspect they may actually prove harmful rather... | [
"I presume that \"nano-silver\" is a new, buzzwordy name for colloidal silver. Silver is a legitimate external antiseptic (for disinfecting wounds, for example), but internal use is dangerous quackery.",
"There are no proven benefits to ingesting colloidal silver, and in addition to having several risks, large do... |
[
"Can therapy really cure mental illnesses or is it an outdated method?"
] | [
false
] | As I've understood, a lot of mental illnesses can be connected to an unbalanced production of neurotransmitters, e.g too much dopamine and too little serotonin leading to OCD. Can all mental illnesses be cured simply through drugs, either existing or potential? Are mental illnesses simply due to a chemical imbalance? Or is therapy a modern, effective and recognized approach to these disorders? | [
"Many mental illnesses are indeed caused by physical differences in the brains of the sufferers from the baseline population. However, at the moment, our knowledge of the mechanics of the brain is not so great that we can simply fix that; the many interlocking systems mean that adjusting one part will quite often l... | [
"It is also not particularly productive to think of therapy as a \"cure\" in a medical sense, and at the same time, it is very helpful to consider that mental illness, while certainly a disease rooted in physiological causes, manifests in symptoms that alter the way that you see and understand yourself and the worl... | [
"It should also be emphasized that therapy doesn't 'cure' mental illnesses. As Syreniac correctly pointed out, modern day therapy is about controlling or correcting bad behaviors. CBT came out of cognitive and behavioral therapies which used to be separate, they came together because they both were founded upon e... |
[
"Do planets in pictures of gaseous looking galaxies actually have gas in the space around them?"
] | [
false
] | null | [
"\"Gaseous-looking\" is kind of both right and wrong. They might look gaseous because galaxies have a LOT of stars. Interstellar space is quite empty, but most of the stars might blend together in the picture and make a bright fog. More clarity means you can see more stars in said fog.",
"On the other hand, inter... | [
"Even the crowded parts of space are empty. The densest nebulae contain about ",
"10,000 molecules per cubic centimeter",
", which is a quadrillion times less dense than air at sea level. ",
"If you link to a picture then other Redditors and I can tell you what you're looking at in a bit more detail. In some ... | [
"The planets don't, as per your question, but the spaces in between stars has a ",
" sizeable quantity. The planets mostly just have their own atmospheres and there is whatever intrastellar dust is around their parent stars...which isn't much, just like her, but it's enough to ",
" like a lot on a picture, esp... |
[
"How can I identify a bird simply by its call?"
] | [
false
] | Every morning between one and two a.m I hear an amazing bird call, and I would love to find out what it is. I live in the southeastern United States, but I'm sure that doesn't help but so much if at all. I once heard on NPR that an app was being worked on similar to Soundhound to identify bird calls, however who knows when that will come out . I searched for an ornithological based /r/, but couldn't find one especially using my phone, so I figured this may be a good place to start. | [
"A quick google search gave me these:",
"-",
"eNature",
"-",
"Birding by ear",
"-",
"Guide to NAm birds and songs",
"-",
"iBird"
] | [
"Record it and post the sound"
] | [
"There is an iPhone app called \"Chirp!\" that has calls based on region. My daughter has been using it to learn the birds in our area, she's gotten pretty good."
] |
[
"Did Antarctica's land wildlife go extinct? Or did it evolve into the marine wildlife that lives there presently?"
] | [
false
] | Given that was temperate and presumably inhabited by land animals, and , where did all the animals go as Antarctica became colder/drier? Did they go entirely extinct, or are some of the pinnipeds/cetaceans/birds that live there now descended from antarctic animals? ) | [
"Seals originated in or near the ",
"arctic",
" and cetacians originated in ",
"Pakistan",
", so they aren't from Antarctica at all. Penguins did ancestrally live in the southern hemisphere, however they were flightless and aquatic long before Antarctica got it's glaciers. See this early penguin from New ... | [
"I think it wasn't so much that the speed exceeded their ability to adapt-rather, the endpoint was just too harsh for anything to survive. Not only is Antarctica incredibly cold year round, it's nearly devoid of plant life (2 flowering plant species, I think, and they only live in a few places around the edges) an... | [
"Thank you! ",
"It's interesting to think that, at some point in Antarctica's history, the rate of climate change exceeded the animals' abilities to adapt. And not just for some of them, but ",
" of them. Especially considering how slow continental drift is.",
"It's too bad we can't easily search for fossils ... |
[
"Why do some countries (Japan, Norway, etc.) which have reasonably good economies have such low exchange rates with USD?"
] | [
false
] | Question is fairly self-explanatory. I guess I've always sort of interpreted a currency having a low exchange rate with the US as a sign of the country in question being economically weak, but I'm noticing that countries which seem reasonably prosperous, like Japan and Norway, also have this going on. For example: 1 Norwegian Krone: $0.04 1 Japanese Yen: $0.0098 I know the prices of things in these countries is often similar to the items' price in the US, once you convert (e.g. Japanese vending machine prices vary from 50 to 3000 yen according to Wikipedia, which is between about $0.49 and $29.40). Do some countries prefer to just have a single unit, rather then doing the dollars/cents thing? Is there some historical reason? Am I just horribly misinformed about these countries' economic state? Please enlighten me, this has been bugging me for awhile. | [
"You numbers are wrong. 1 krone is 0.16 US$. ",
"Until 1933 i US1$ equaled 1.5 grams gold. Norway had 1 krone equaled 0.4 gram gold until 1931. So at that time the rate was 1 krone was 0,26 US$. Since that time, deflation, inflation, differences in real trade and financial trade and differences in interest rate l... | [
"It doesn't matter what their exchange rate is with the dollar, ultimately. If I have a \"dollar\" coin, or a 100-yen coin, or a 10",
" space bucks coin, but they all buy me the same thing, the difference doesn't much matter. I mean, the difference is kind of obvious with the Yen and dollar. Replace \"Yen\" with ... | [
"You numbers are wrong. 1 krone is 0.16 US$. ",
"Actually, my numbers were correct as of last night. It appears that there was some kind of weird spike sometime last night.",
"Thank you for the explanation, though."
] |
[
"Can someone explain Quarks in a simple manner?"
] | [
false
] | I've been curious about the subject, but any time I try to look up the page on Wikipedia, I always get too confused by the terminology. So since I'm such a slow person, I'd like a simpler explanation as to what Quarks are, and what they actually do. | [
"Quarks are (as far as we can tell) fundamental constituents of matter, so they are not themselves made of something else. They possess mass, electric charge",
" (±1/3 or ±2/3) and what we call \"color\" charge of green, red, blue. Or if they are antiquarks they can have, antigreen, antired, and antiblue.",
"Wh... | [
"Doesn't this mean that there is actually an extremely small amount of actual matter in us? Is matter even the right word I'm looking for?",
"I don't think there is a word for what you're looking for.",
"In a strictly illustrative sense, yes, if you added up the individual masses of all the fundamental particle... | [
"Okay so protons and neutrons are composed of 3 quarks. Are electrons composed of anything or are they still considered to be fundamental constituents of matter?",
"Electrons are leptons, which are considered fundamental. The fundamental fermions are the six leptons (electron, mu, tau, and the electron/mu/tau neu... |
[
"Do photons experience any form of time?"
] | [
false
] | After reading , I began wondering if this is a legitimate understanding of the implications of relativity theory. So is it true that because photons only travel at the speed of light, they experience infinite levels of "time dilation" and "length contraction"? I understand the claim about time slowing down as one approaches the speed of light, but are the claims about photons experiencing zero time merely conjectures? Or are they legitimate implications of relativity theory? | [
"We know of absolutely no tachyonic particles. And we have good reason to suspect that such things cannot exist. (they'd cause logical paradoxes)"
] | [
"First off, tachyons are only hypothetical and probably do not exist.",
"Secondly, you cannot \"pass\" the threshold... there are 3 cases:",
"Even if they exist, is makes no sense to talk about what tachyons \"experience\" because they are a particle that we cannot communicate or \"use\" in any fashion. ",
"w... | [
"you can't speak of any observer moving at the speed of light. But in the limit that an observer ",
" the speed of light, the length along the line of motion contracts away to zero. How long does it take to cross zero length? Zero time."
] |
[
"What would happen if a bee/wasp stung me on the eyeball?"
] | [
false
] | Let's assume the person in question has no allergy to bees/wasps/whatever does the stinging. In what ways would the effect differ from being stung on skin? Would blindness result? Would the effect of stings (edit: the effect of the stinger's penetration has been pretty well handled; how about the effects of the toxins?) on the white, iris, or pupil be different from each other in any appreciable way? | [
"Not necessarily. I had a stick go through the pupil of my eye and I don't have a 'scar' on my eye. (It only went through the front of the eye. If it had hit the back then I'd likely be blind. But I don't think a stinger is big enough to hit the back.)",
"I would think the poison would be the real problem."
] | [
"happened to me when i was 10.",
"fuckin hurt. a lot. little fucker dive-bombed me. ",
"i managed to snap my eye closed a fraction of a second before he got me, so the stinger went through my eyelid and into my eyeball (sclera). had my mom pull the stinger out (while crying/screaming in pain).",
"no lastin... | [
"I remember this happened to a friend of mine in like kindergarten, he didn't go blind but did stay out of school for about a week iirc. Of course, I don't know/remember where exactly this happened, probably on the sclera (white part). I would imagine if it happened on the pupil/cornea it would cause some scarring ... |
[
"How possible is it for a habitable planet to have a larger land surface area than Earth, but have about the same gravity on the surface (i.e. have a lower density)?"
] | [
false
] | [deleted] | [
"Tldr: just under double before it starts becoming a gas giant and a whole new problem."
] | [
"The surface gravity g is equal to GM/R",
" , where G is the gravitational constant, M is the mass of the planet, and R is the radius of the planet. So, if the surface area goes up, R increases, and as long as the mass goes up as the square, then it's okay, e.g. if R increases by 3, M increases by 9, or if R chan... | [
"Additionally, you can still have continents that don't touch one another on an Earth-sized planet. Assuming that it was geologically identical to Earth, it would depend on what stage of the supercontinent cycle it was in and on the age of the planet."
] |
[
"What happens to mosquitoes when they suck your blood while you are intoxicated?"
] | [
false
] | I apologize if this has been asked before, my attempts at google and reddit search have not shown any actual studies or questions asked on this. So does the alcohol in your blood have any affect on a smaller mosquito? I'm assuming that either the alcohol is not concentrated enough to affect the mosquito, or the sac that the mosquito stores the blood in does not absorb the alcohol? Maybe a better understanding of how mosquito store blood would render this whole question moot. This could also go for any type of substance in your blood. Like if I drank some sort of human safe DEET. Could I be mosquito's destroyer of worlds? | [
"Scientists routinely puff ethanol vapors at insects and measure their sensitivity with devices called inebriometers. Bugs are no lightweights, often withstanding vapor concentrations of 60 percent alcohol, far more than what’s in our blood after a couple beers. “Someone who’s had 10 drinks might have a blood alcoh... | [
"The article is very vague and for all it says it may very well be fruit flies (which feed off of sometimes rotting fruits) that can handle such a high amount of alcohol, unless I am missing something"
] | [
"It's not great but gives a good ball park. The other problem I have is that vapor pressure does not translate to BAC."
] |
[
"How big can a crystal get?"
] | [
false
] | I'm sure many of us have heard about some planets being discovered that could basically be giant diamonds. (And that's a whole other complicated can of worms, but let's not open it here.) I think a lot of people probably hear "diamond" and think that this is the type of thing where you'd be able to see some sort of crystaline structure from space - facets, planes, etc. I assume that that's not possible, because that would require the crystals to form at a massive scale. However, I don't actually know if my assumption is correct, nor why. What prompted this line of thinking was a discussion in another sub where an of the Omega/Swan/Horseshoe nebula was being (needlessly) debunked by Phil Plait. It's clearly fake, but it got me wondering how large a crystal formation can actually get. There are those amazing ones in the , though obviously there's a huge difference between a crystal that's 39ft tall and one that's 15 light-years tall. Is there an upper-boundary for how big a crystal can get? Gravity and mass are probably the biggest factors, of course. And even if you had the material and conditions to form a 15 light-year tall crystal formation, the mass would probably collapse into a black hole. But let's speculate a little. Could a mile-long crystal exist, for example? If we ignored mass and/or gravity (except for what is needed for crystal formation in the first place), and assumed a limitless supply of source material, could a crystal theoretically grow forever? I really don't know anything about crystallography, or even anything beyond the most basic mineralogy. (I'm a web designer.) I apologize if I'm using terms incorrectly. Thanks! | [
"Without knowing the exact answer, at the high end you'll be limited by gravity and general relativity. Crystals by definition are materials with repeating units (the \"unit cell\"). That can only repeat indefinitely in \"flat\" space. For example, a crystal is only a crystal if the axes of the unit cells in the cr... | [
"No crystals are perfect. All crystals have equilibrium point defects due to entropy and most have some concentration of line defects, which are non-equilibrium, but low enough energy that they are easy to produce and difficult to completely remove (more so in metals than in ionic and covalent crystals). Most sol... | [
"This is a single crystal",
". A planetary diamond would be spherical due to the gravity that allows the crystal to form. Also it will have to have something over the top of it providing the pressure to form the crystals, so it will never look like one big crystal.",
"I don't have enough knowledge to say if i... |
[
"I recently quit using tobacco after 10 years of use. My family is telling me that I need to do a cleanse. Is there any scientific evidence to say that these detoxifying cleanses work or are they BS?"
] | [
false
] | I've heard a lot about body cleanses and detox but I'm wondering if there is any legitimate scientific research done on the subject? For example, members of my family do a cleanse where they drink lemonade/maple sugar/cayanne pepper for a week straight with no food, claiming it detoxes them. When I search for information on the matter all I can find are new age/holistic websites that I do not trust to be unbiased. Thank you for any relative information. EDIT: BTW I was a chewing tobacco user. | [
"The first question I ask about anything like that is whether they can name the specific \"toxins\" that are supposedly being removed. They generally do not get specific because they're not actually doing anything helpful."
] | [
"It's complete bullshit. And unhealthy."
] | [
"Obviously I'm just here to lend my grey tag to the answers. (/sarcasm) Cleanses are bullshit. If we needed cleanses we'd have died out as a species long ago. "
] |
[
"When we view distant cosmic bodies, do relativistic effects cause us to see their changes at a slower rate since they are moving so fast relative to us?"
] | [
false
] | I was under the impression that galaxies are flying apart from each other at a pretty rapid pace. I was also under the impression that time slows down for fast moving objects. If we can see the light from one of these galaxies as it is soaring away, wouldn't that mean that from our vantage point that they would move/change very slowly? For example- Say we observed a distant galaxy rotating while is is soaring away from us at speeds close to the speed of light. Would the rotation speed we see correspond to the rotation speed measured by an inhabitant of that same galaxy? If this is already a thing, how does it affect our assumptions and observations about distant objects, and how to we compensate for it? | [
"You're using a speed almost 3 orders of magnitude too large. Objects receding at about the speed of light are at a redshift of about 1.5."
] | [
"Realistically this isn't an observational effect, because to look far enough away/back in time for the object to be receding at relativistic speeds you will be looking at redshifts where galaxies haven't formed yet. We can't see even primordial structures here because they are 1) too faint, and 2) obscured by neut... | [
"Can you elaborate please? How do you get this? Are you talking about taking into account the redshift dependence of H?",
" Oh god you're right - what a retarded mistake to make! I'm so used to working with 3x10",
" km/s - I got my wires crossed with 3x10",
" ",
"/s :)",
"Repeating with v = 2.5x10",
" k... |
[
"What is the most accurate measurement?"
] | [
false
] | Hello askscience, I am a chemistry undergrad in an analytical/instrumental chem course, and just learned about one of my professor's research topics that is a method with detection limits theoretically in the parts per quadrillion, which got me thinking. I was wondering: what is the most accurate measurement technique out there? In terms of detection limit, or measurement uncertainty, or whatever. I realize that I'm asking a question that could be taken several ways, as you can have accuracy in looking for a concentration, a distance, or a whole host of other things, but I feel like it would be really cool to hear about things from a variety of fields. Thanks all! | [
"The quantity that is often cited as being the best measured is the magnetic moment of an electron (related to how an electron responds to magnetic fields). It is very close to two, and half the deviation from 2 has been measured as 0.00115965218073(28), where the brackets indicate uncertainty on the final digits. ... | [
"This is the current winner in the verified predictions category, but in terms of percent measurement error, ",
"LIGO",
" should be capable of detecting a change of length on the order of one part in 10",
" Using interferometry to measure a 1064 nm laser over a distance of 600 km is basically cheating, but I ... | [
"A very ",
"recent experiment",
" managed to make a measurement with an accuracy approaching the Heisenberg uncertainty limit. This means that the uncertainty associated with this measurement is roughly as small as is physically possible, because quantum mechanical considerations preclude precise knowledge of t... |
[
"Are there any studies or can anyone explain to me in the most objective way possible why some people can smoke all their lives and never get any kind of cancer?"
] | [
false
] | My girlfriend's grandmother has been smoking UNFILTERED pall malls since she was in her early 20's/late teens, and she is 80 now and is still healthy. WTF? | [
"There is hardly anything that has a 100% guaranteed chance to cause cancer. Cancer development is an extremely complicated process which requires successive mutations in cell populations over your lifetime.",
"Smoking increases your RISK of cancer. ",
"According to the CDC",
" lifetime smoking increases yo... | [
"Smoking increases the probability that you will get cancer, but there is always a chance that you will not."
] | [
"Just because something is likely to happen doesn't mean it will. "
] |
[
"Is it possible for us to catch 2 or more variant of covid-19? If so, can those variants inside our body fuse/combine to mutate into another variant? or mutate individually?"
] | [
false
] | null | [
"This is a about segmented viruses. Influenza is segmented, Covid is unsegmented. So this doesn't apply."
] | [
"Yup. ",
"A little known fact is that viruses can “have sex”, all out “orgies” to be a bit more precise. ",
"When two or more viruses enter a cell, it’s possible for their genes to combine/interact/exchange/affect or otherwise mix with each other resulting in hybrid viruses, some of which can remain viable. ",
... | [
"More than one coronavirus can infect the same cell, and when that happens the coronaviruses can recombine. That is, as their genomes replicate, the replication factors can jump from one genome to another, so that you end up with part of the progeny genome coming from one parent, and another part coming from anothe... |
[
"What keeps an object in orbit at the same distance instead of being pulled toward the source of the gravity?"
] | [
false
] | Eg what keeps an satellite at the same distance from earth? and why is it not pulled in? What keeps earth from being pulled into the sun? | [
"We ",
" being pulled towards the major source of gravity in our Solar System (the Sun), but the reason why we don't fall into the star is because our planet is moving at a pretty high rate of speed relative to it, with the vector of our travel being roughly 90 degrees tangent to the Sun's center of mass - our pl... | [
"this diagram may help clarify your point"
] | [
"It's falling with a lateral speed that makes it constantly \"miss\" hitting the planet. "
] |
[
"This may be a dumb question, but if losing weight requires simply eating less calories than your body burns, what are the biggest differences from eating healthy or poorly?"
] | [
false
] | If I understand correctly, if your body burned, say, 2500 calories a day, and you ate 2000 calories of fast food, you'd lose weight. If you ate 3000 calories of extremely healthy food, you'd gain weight. Obviously eating healthier food is better, but why exactly? | [
"This is complicated because your question isn't entirely clear. If by \"health\", you mean weight gain/loss, it is very hard to overeat truly healthy food. have you ever tried eating 3000 calories of meat and vegetation? your stomach and satiety hormones simply won't let you. healthier food also tends to impact in... | [
"It's definitely not a dumb question. ",
"Some things to consider/bear in mind:",
"Eating \"healthily\" is a poorly defined concept, and the many items can be both healthy in one regard and unhealthy in another (for example, the association of certain types of fats, omega-3's, with both improved metabolic healt... | [
"being healthy is not maximized by minimizing weight, thats the first point it guess, also every kind of \"unhealthy\" is only a matter of dosage. For example protein is considered healthy. But too much protein is unhealthy. Sugar is considered unhealthy but without it(or it being split out of more complex carbs) y... |
[
"When our epidermis grows with our size, does the number of nerve endings increase to maintain a constant density, or are they simply spaced further apart?"
] | [
false
] | And is the phenomenon the same or different between adolescent body growth/adult weight gain? EDIT: Thank you for the responses! Looks like my question has been answered quite thoroughly. This is why I love , I'd been wondering about this for ages, and may have gone one wondering if you guys hadn't explained it. Great work! | [
"the number of sensory nerves innervating your skin is determined by the number of neuronal cell bodies in the dorsal root ganglia. During gestation this number increases through division (some die off) and reaches a stable number. Neurons are 'post-mitotic' and do not divid further. The neuronal cell bodies by the... | [
"Seems unlikely. The sensation you get from stimulating your skin sensory nerve terminals is the result of 2nd and higher order processing in the brain. So it seems likely to me (although I'm a peripheral nerve man not a CNS guy) that the brain will have already calibrated to your particular state of arborization/s... | [
"Seems unlikely. The sensation you get from stimulating your skin sensory nerve terminals is the result of 2nd and higher order processing in the brain. So it seems likely to me (although I'm a peripheral nerve man not a CNS guy) that the brain will have already calibrated to your particular state of arborization/s... |
[
"Will light be refracted by any glass like object? Can it be treated to decrease the amount of refraction?"
] | [
false
] | I'd like to think I remember this topic from my classes but I have been asked this question in such a way that it made me question my knowledge. As far as I know any glass like object will refract light that passes through it to a certain degree. Can this effect be controlled by the manufacturing process of said object? Here is the actual situation I'm dealing with. I am a customer service rep handling warranty claims on motorcycle helmets. I have a customer who is complaining to me that the visor on his helmet refracts light and distracts him and could pose a safety risk. I had thought that any glass like material will do this. Can this effect be lessened by the way it is manufactured? Thanks for your time guys. | [
"Light is refracted whenever the light encounters a medium with a different refractive index at any angle other than normal incidence (anything other than perpendicular to the surface). Typically this means the surface is curved like a lens or tilted, etc. but it can also happen when the light is coming into, or go... | [
"I may be using the wrong terminology. It looks as if the visor is acting as a prism. The white light is being separated into a spectrum."
] | [
"Flat sheets will not bend light (or rather they will refract the light back by an equal amount into the original direction and the total effect is very small). This probably wouldn't help in making a helmet visor, sadly. There's not really any way to prevent refraction in general through a material, especially har... |
[
"Why doesn't an alpha decay release a huge amount of energy like nuclear fission?"
] | [
false
] | I've heard the word "tunneling" used in this context, but don't really understand what's going on... | [
"The idea of interest for this is ",
"Nuclear binding energy",
". The total energy of the nucleus is the mass of all of the nuclei ",
" the binding energy of all the nuclei. ",
"As you increase the number of protons and neutrons (A) in the nucleus, the amount of binding energy per nucleon (proton or neutron... | [
"That's just where the equilibrium point happens to be.",
"Let's say you are selling hot dogs. At $1, you sell a whole lot, but for not much profit per unit. At $2, you sell fewer at a large profit per unit.",
"So you have two competing forces, volume and profit margin. Some where in the middle, say, $1.38, ... | [
"There are 3 effects that are important for understanding this.",
"First, the strong force by itself tends to favor bigger nuclei. So you gain binding energy by adding nucleons. But as you go up to bigger nuclei, the effect of adding one more gets smaller.",
"Second, since protons and neutrons are fermions, the... |
[
"Any chemists in the house? Can fluoride really cause hypothyroidism?"
] | [
false
] | Is this legit? If so, what does this have to do with the autoimmune disease Hashimoto's thyroiditis (which causes low thyroid levels because of an attack by antibodies on TSH and TPO receptors on the thyroid gland). It would seem that this is an entirely different path to hypothyroidism. I looked for epidemiological evidence of thyroid disease on the rise, but because of changes in testing procedures and disagreement on proper lab ranges, it's hard to say how many people have thyroid disease now, much less how many had it 60 years ago before the time of ubiquitous fluoride... | [
"There is a LOT of pseudo-science around fluoride use in drinking water, and I'm sure you've found it by conducting Google searches. Many of them ignore basic concepts (dose-dependence is a big one i.e. taking the results of a high dose study and implying a low dose has the same effect) or cherry-pick research wit... | [
"There is a LOT of pseudo-science around fluoride use in drinking water, and I'm sure you've found it by conducting Google searches.",
"I just want to second this. Flouride ",
" in water is a very long running psuedo-science. Going back at least far enough to have been mocked in the movie Dr. Strangelove. ",
... | [
"Take it from a chemist, their opinion is not equal to the findings of the CDC, not even close. The CDC doesn't have an \"agenda\" beyond public health, implying that they do is ignorant and some what offensive to serious scientists. "
] |
[
"Does wiping off your sweat prevent the body from cooling down?"
] | [
false
] | Does the cooling effect come from the sweat absorbing the heat on its way out or should you leave it and not wipe it to lower your temperature more efficiently? | [
"Yes, sweating is based on evaporative cooling, where the phase change from liquid to gas absorbs heat energy from its surroundings (including your skin and the warm blood carried by the ",
"superficial veins",
" from deeper tissues. So yes, wiping off sweat actively hinders your body's natural cooling mechanis... | [
"All correct, however you can actually hinder your ability to cool by sweating too much. If you're absolutely dripping sweat, like totally soaked, there will not be much evaporation taking place (the phase change that's most important). Instead, you're just warming up your sweat a bit before it drips off you, gets ... | [
"I'd add that when dripping sweat, the sweat droplets are mostly spherical, ans as such have a small surface area where phase change happens. By wiping off the sweat, you'r effectively smearing it, greatly increasing the surface area and accelerating evaporation and cooling."
] |
[
"How do we know the structure of molecules?"
] | [
false
] | null | [
"This has been asked a few times, so you may want to do a search.",
"In short, chemists use a variety of tools to determine the structure of molecules. These techniques include:",
"A chemist looking to determine the structure of an unknown molecule would use a combination of these tools to come to a conclusion.... | [
"In addition to the methods outlined by ",
"/u/Joe_Q",
", there are some new techniques coming out in the microscopy world. The most notable is cryo electron microscopy (cryoEM) which actually ",
"won the 2017 chemistry Nobel Prize",
"With cryoEM, you can use a transmission electron microscope to essentiall... | [
"I agree that it is powerful, but in organic chemistry at least (which is where I go when I hear \"the structure of molecules\") it is not at all a common structure-determination tool."
] |
[
"How long do you have to be exposed to the sun to get the same dose of vitamin D as your daily supplements?"
] | [
false
] | null | [
"It will depend on the strength of sunlight, but ",
"this study",
" found >1hr per day was sufficient in their study population in India. However, it seems that time of day and latitude would have a significant impact on duration needed to achieve healthy levels of vitamin D production."
] | [
"Depends on your genes and how dark your skin is/how much melanin. And there is many different amounts of vitamin d supplements. I take 5000iu a day. Usually 20-30 mins a day of full exposure is adequate. Making sure you get enough K2 is important."
] | [
"Strange that an important factor is not mentioned which is how much skin is exposed, as in how much clothing they're wearing. This study is in India so there's going to be more sun than in North Europe. ",
"Considering its hot in India, usually, they probably weren't wearing much, but if it's colder, not only is... |
[
"Would science in general (I mean in academia in practical terms) benefit from discarding all prior assumptions in every field and trying to formulate fresh sets of hypotheses based solely on observations to date?"
] | [
false
] | null | [
"This isalready practiced in science, to the benefit of scientifical progress. My favourite example of this is Newton's law of universal gravitation, which is known to be imprecise in some regards, but still accurate enough to describe most cases."
] | [
"Some Examples for discarding and refining of prior \"knowledge\" in science:",
"The latter point is explained at length ",
"on Wikipedia",
"."
] | [
"Some Examples for discarding and refining of prior \"knowledge\" in science:",
"The latter point is explained at length ",
"on Wikipedia",
"."
] |
[
"Can individuals evolve with respect to Epigenetics?"
] | [
false
] | [deleted] | [
"Totally agree with your first part, great explanation. +1.",
"In regards to transgenerational epigenetic inheritance, in humans/mammals the evidence definitely isn't great, but some epigenetic marks survive meiotic reset in animals, plants, and other eukaryotes, particularly those where the germ line isn't seque... | [
"Totally agree with your first part, great explanation. +1.",
"In regards to transgenerational epigenetic inheritance, in humans/mammals the evidence definitely isn't great, but some epigenetic marks survive meiotic reset in animals, plants, and other eukaryotes, particularly those where the germ line isn't seque... | [
"Epigenetics is a method of gene regulation. It's a way of turning genes on and off. That's all. Your own genes are turning on and off in response to outside stimuli ALL THE TIME. Gene regulation isn't a new thing; it's been known about for a long, long time.",
"Epigenetics is getting lots of attention only b... |
[
"Electronics on Airplanes"
] | [
false
] | null | [
"Bit of your own medicine, Doctor. From the first link in your search:",
"It is not, contrary to popular opinion, to force you to pay attention to the safety briefings. If that was the case, you wouldn't be allowed to have books out, and you couldn't sleep - neither of which is prohibited.",
"http://en.m.wikipe... | [
"http://money.cnn.com/2012/12/09/technology/in-flight-cell-phones/"
] | [
"That's not the issue, it's passenger safety and cost for testing to prove the regulations are overly conservative.",
"\"the cost of an accident, should one occur, could be extremely high in terms of human life and the risk is completely avoidable in that no one absolutely needs to use their mobile phone in fligh... |
[
"How can computers calculate sines so accurately?"
] | [
false
] | I've been learning about rewriting a function as a series in my Calculus class, and my professor mentioned that computers need to use series to approximate the values for functions such as sine. To calculate a sine accurately, you need a good number of terms, and even with that, the error from using a series with a finite number of terms increases by quite a lot as the sines argument (for lack of a better word) distances from zero. I wrote a rather simple calculator program to compare the time of executing the Taylor series with <0.01% error to the built in program, and found that the built in program is much faster, especially as the input numbers got larger. How does a computer calculate these functions so quickly and accurately? Is it even using a Taylor series, or some other approach? | [
"First of all, you can (and really should) always arrange the argument of your sine or cosine to be between 0 and π/4 by using periodicity and identities. In this small interval the error in the series expansion is much smaller, and controlled.",
"However, computer implementations (like C built-in functions) do n... | [
"It looks like GNU libm (standard sin() on linux) uses a combination of techniques, depending on the input (at least for x64 - there are different implimentations for different architectures). The code is mostly black magic to me, but it does seem to involve a Taylor series.",
"https://sourceware.org/git/?p=glibc... | [
"There's also CORDIC in there in one of the cases, though it's barely legible. If the angle is pretty small, you can gst away with only two or even one Taylor term and that might be faster than CORDIC in that case"
] |
[
"does the vitamin c from my lemon tea breaks down when i'm boiling it?"
] | [
false
] | i heard that vitamins are destroyed when cooked so i googled it but haven't found any thing that satisfied my curiosity. i found the melting and boiling points for vitamin c but i have no idea what to make of them so im asking for your counsel. p.s. sorry for any grammar mistakes and punctuation errors | [
"Vitamin C doesn't decompose until around 370°F/190°C so boiling water alone won't destroy it. It does, however, react with oxygen in the air. The oxygen in the water combined with the high temperature will probably lead to some of the ascorbic acid being oxidized but unless you're leaving it out boiling for a very... | [
"It depends on the kind of tea pot you have. Copper catalyzes vitamin-C ",
"http://en.wikipedia.org/wiki/Vitamin_C#Food_preparation",
" and ",
"http://www.ncbi.nlm.nih.gov/pubmed/3595980",
". ",
"Apparently ",
"copper teapots are a thing",
" so this is quite possible.",
"Traditionally someone boil... | [
"well thanks, i do boil my water but the tea i drink is pretty tasteless anyway "
] |
[
"Why do your arms float up after pressing outwards on a door frame with locked elbows?"
] | [
false
] | I make educational science videos and I wanted to make one about this phenomenon a while ago, but I was unable to find any satisfactory explanations. My understanding is that it's a generalized muscle effect - you can induce something similar by making a fist and squeezing really hard for a while, then gently trying to open your hand. It will feel 'locked up'. I saw various sources claim different effects were responsible: that excess calcium buildup was stimulating the muscle fibers, that muscle spindles were somehow getting confused and setting a false equilibrium point for muscle lengths, or that the opposing set of muscles were getting tired trying to oppose the anticipated movements leading to mismatched muscle tone. Can anyone shed some light on the accuracy of any of these claims? I'd love to make a video about it if I can get a well-supported explanation. Thanks for your help! | [
"EDITS: Here is how I Think it happens, and here is a picture for reference : ",
"http://imgur.com/PaYsC",
"When you contract the triceps (extrafusal muscle), an intrafusal muscle also contracts, wich slows down signaling along the 1a sensory neuron. A gamma motor neuron then activates to stretch out the intra... | [
"I created this account to comment on this. From what I can tell you're on the right track, but if I recall correctly it works more like this: The first thing to remember is that nerve signals are sent in pulses, and your brain reads changes in pulses (speeding up or slowing down) as corresponding sensory signals (... | [
"I appreciate the responses I've gotten here so far, but ironically I now have two people supporting two different options out of my original three. As in all of science, the truth is probably some combination of my conveniently separate options. Still, it would be really great to have someone provide definitive su... |
[
"Would everything on an extrasolar planet be dark to human eyes?"
] | [
false
] | null | [
"Other suns might have their peaks at completely different frequencies",
"Yup, it depends on the temperature of the star (and a couple of other things because they aren't perfect ",
"black bodies",
", but that's not really important here)",
"and not much light of the kind that we are used to seeing.",
"No... | [
"Other suns might have their peaks at completely different frequencies and not much light of the kind that we are used to seeing.",
"Not really. The Sun is a ",
" average star, and there are tons similar to it. Most stars have peak frequencies in the visible range anyways, so it wouldn't be as extreme as you're... | [
"Every bona fide star emits visible light in a more or less thermal spectrum, like the sun."
] |
[
"What is happening physiologically when we feel so happy our heart feels like it will burst?"
] | [
false
] | null | [
"Sometimes when I am extremely happy, my breath catches and my chest feels so full. Alternatively, when I feel very emotional or sad, my chest actually aches. What is going on in my body? "
] | [
"I'm not a cardiologist (However I am working on my ACLS certification), but I'll take a shot based on what I've learned from what I've taught about the heart and related tissues, and what I've learned in my ACLS studies.",
"That \"ache\" is a result of a combination of many things, and is called a Palpitation. A... | [
"You are experiencing premature ventricular contraction (PVC), also known as your heart \"skipping a beat\""
] |
[
"When flying away from earth at the speed of light, why does \"my\" time stop passing and not the earths?"
] | [
false
] | Since there is no magical static grid covering the universe that tells us how fast we travel, speed can only be measured between two observable objects i.e. inertial systems. So if I fly away from earth at the speed of light, there is a relative speed c between me and earth. Couldn't one say that earth is flying away from me at the speed of light instead of vice versa? What is the difference between me and the earth that makes "my" time stop? | [
"Because when you come back to earth, you change your frame of reference while the earth remains in the same frame of reference. You change your direction of travel. This causes the symmetry to stop working as before."
] | [
"Let's make it so that you're travelling close to c and not at c so the good folks here at ",
"/r/askscience",
" don't get all mad.",
"When you're travelling away from earth, the people on earth view your time as passing slower than on earth. However, you view earth's time passing slower than yours. This is v... | [
"That isn't a solution of the twin paradox that IS the twin paradox (or rather one of them). It arises because the special relativity arguments used to make the statement do not include acceleration, which is necessary to get the twins back into the same frame."
] |
[
"working on hourly basis on grant money instead of Physics RA?"
] | [
false
] | So I plan to start grad school in Physics this upcoming fall, but for the summer, I have nothing to do, so I'm willing to work for a prof as a volunteer research assistant. I missed the deadline to work under an RAship for the summer. I've already agreed to work as a volunteer, but is it possible to get hired on an hourly basis with the prof's grant money, so I could work for him even if it isn't officially an RA? Could I work out an hourly wage that would be comparable to an RA stipend? I mentioned this in one of my previous emails to this prof, along with talking about renegotiating the deadline for an RAship, but he just told me the dept is strict about deadlines. So I don't know if he actually read my question about trying to work out a salary but not work officially as an RA. | [
"r/askacademia",
" is probably a more appropriate place for questions like this."
] | [
"I think only your professor can really answer this question..."
] | [
"There is also a difference in the answer depending upon what country you are in. There are tax differences between most RAships and hourly pay. There is also the difference between different titles on your resume, provided the work is of the same nature."
] |
[
"What is the temperature of a particle moving near the speed of light?"
] | [
false
] | Such as particles in the LHC. | [
"Temperature is a statistical property of an ensemble. A single particle doesn't have a temperature in any meaningful sense."
] | [
"temperature if a transfer of energy between things.",
"You're mistaken. Heat is a transfer of energy. Temperature is (basically) a system's tendency to give off heat. More generally, it's defined in terms of a partial derivative of entropy, which means that every system has a temperature, not just ones for wh... | [
"Particles in the LHC do not technically have a temperature until they collide, to be specific. ",
"Soronume pointed out a flaw in that analysis, that heat is the transfer of energy, which is different from temperature. Thanks.",
"Additionally, the particles are not \"heating up\" in the traditional sense when ... |
[
"Would we be better at mathematics if we weren't bought up using a base-10 number system?"
] | [
false
] | Decimal may be an easy-to-grasp concept because of the whole ten fingers thing, but would we be at mathematics if, for example, we were taught from a young age to use hexadecimal (base-16) instead? | [
"Very little mathematics has anything to do with the base for decimal representations of numbers. (For that matter, a lot of mathematics isn't really about numbers at all!)"
] | [
"Not really. How we represent numbers does not really have anything to do with the math behind it. ",
"Ten digits are easy to remember. We have ten fingers and can use them to learn the ten digits. The word digit stems from the latin word for finger. It might be more work to remember 16 digits and have a unique ... | [
"By \"we\" do you mean a particular country or humanity in general? Because we, as in the human race, have advanced mathematics quite a bit. If you mean we as in the US, Canada, or wherever you might be from, there are plenty of other countries that use the same base-10 number system and have higher proficiency num... |
[
"How do fish and other marine animals survive the crushing pressure of the abyss?"
] | [
false
] | I was reading on the recent discovery of the Airbus that had crashed off of Brazil a few years ago, I think it's about 2 1/2 miles down -I thought wow, that's a lot of pressure. Then I began to wonder how ocean life can survive such crushing depths...any ideas? relevant link: | [
"Well the pressure inside them matches the pressure outside.. They're kinda equillibriated with their surroundings, and hence they should be fine. The structural properties maybe very slightly different but I don't see any reason why any biological process should happen in a different manner under very high pressur... | [
"Liquids are notoriously hard to compress. As organisms are mainly made up of liquids their intracellular pressure simply matches the pressure of the surrounding liquid. The size of the organism is less important than the gasses in it's system. Most marine organisms don't have large pockets of gasses that would cha... | [
"Liquids are notoriously hard to compress. As organisms are mainly made up of liquids their intracellular pressure simply matches the pressure of the surrounding liquid. The size of the organism is less important than the gasses in it's system. Most marine organisms don't have large pockets of gasses that would cha... |
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