title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Does the colour of light affect a plant's rate of photosynthesis?"
] | [
false
] | null | [
"Absolutely. In a way it is semantics, but a different color is really just different wavelengths.",
"The worst rates of photosynthesis occur in, unsurprisingly, the green wavelengths.",
"Here's a pic",
" from the University of Miami that gives a ",
" relationship of wavelength and rate of photosynthesis."
... | [
"Out of curiousity, is green light inherently bad for photosynthesis (less efficient, etc), or is the primary reason that green light bad for photosynthesis particularly because plants are green - and, as such, reflect green light?",
"In essence, if I managed to make a blue plant and still used white light to sus... | [
"It helps me understand why it absorbs two narrow bands. My question is moreover \"why are those two bands not green\".",
"The obvious answer is, of course, \"because chlorophyll green, so they reflect green light, so it wouldn't make sense for them to be highly efficient at absorbing green.\"",
"I simply am wo... |
[
"Why do we use Relative Humidity in all the weather reports? Surely how dry it feels is related to the Absolute Humidity? Or if how dry we feel is because of Relative Humidity, why?"
] | [
false
] | null | [
"Relative Humidity is a handy because it measures the ability of air to hold more water. Humidity (the moisture content of air) effects us because of its influence on the rate of evaporation. Absolute humidity measures the same thing but it is in practice a less useful scale because the saturation value changes so ... | [
"Sling Psychrometer",
": a cleverly simple 19th century instrument to calculate relative humidity."
] | [
"Thanks! That makes a lot of sense."
] |
[
"A question about black holes"
] | [
false
] | [deleted] | [
"Black holes are not \"drains\". They do not \"suck\" matter in. They interact (gravitationally) as any massive object (such as a star) might. For example, if our Sun was replaced by a black hole of equal mass, nothing about the Earth's orbit would change. ",
"As for the \"shape\", the ",
" of a black hole is a... | [
"The event horizon of a black hole is spherical. They seem planar because clouds of gas will naturally form disks due to conversation of angular momentum."
] | [
"There is a preferred axis about a black hole. Black holes can be completely characterized by three properties -- their mass, charge, and spin. This last one is related to your question. Since angular momentum is conserved, anything that rotates as it falls into a black hole imparts that bit of rotational energy to... |
[
"Does the universe have an event horizon?"
] | [
false
] | Before the Big Bang, the universe was described as a gravitational singularity, but to my knowledge it is believed that naked singularities cannot exist. Does that mean that at some point the universe had its own event horizon, or that it still does? | [
"It's more that the question itself is malformed, like asking what happens if you stand at the north pole and go north.",
"Under a Classical GR model, there is no \"before\" t=0. It's not that we just can't determine what preceded the Big Bang. It's that the notion of events preceding the first moment of time is ... | [
" Hmm... didn't expect this to blow up. Anyway, ",
"this is the thread I intended to link earlier",
"; it goes over all the gory details that I either skipped or summarized (possibly sloppily).",
"The big bang is the only naked singularity allowed to exist in the cosmic censorship hypothesis, which otherwise ... | [
"My biggest question is why is it pointless to figure out what happened before the Big Bang?"
] |
[
"Do strategic skills transfer between different games?"
] | [
false
] | If I play a lot of chess will I be better at go, or if I play a lot of strategy video games will it help (to whatever extent) with board games like Risk etc. or since these games have different rules, would the skills for them be mostly independent from each other? | [
"Speaking from experience, fighting games teach a lot about positioning, getting value from resources (like supers), setups for combos, and recognizing how an opponent \"prefers\" to play. i.e. Do they favor throws, blocks, recovery rolls, jumping or crouching?\nCertain card games (like Magic) also reward players f... | [
"Yes. Not always the individual skills themselves, but the methods you used to acquire those skills. You learn how to learn more efficiently and accurately. Abilities like pattern recognition and deductive reasoning are universal to figuring out systems you find in games. There are also some strategic principals th... | [
"Honestly your strategy doesn't really work in Starcraft either, so I'm not sure this really works as a counter-example (I don't know enough about the other games to speak to them). It sounds like you've probably never played competitively on the ladder much. Against AI or other new players you can do pretty much w... |
[
"In a crazy amount of movies, the hero is knocked unconscious and awakes hours later in captivity. How long does being knocked unconscious last?"
] | [
false
] | In an unbelievably large amount of fiction, someone is knocked out often for hours by a blow to the head. However, I've heard somewhere that being knocked unconscious only really lasts a few seconds; any longer than a few minutes probably means brain damage. Given how often I see someone knocked unconscious in movies,... | [
"Depends on why you're unconscious. ",
"If one was hit around the head and just had a concussion ( Traumatic brain injury ) then you would expect to regain consciousness initially rather fast, in the order of minutes, although it wouldn't be unusual to be impaired somewhat for hours, days or longer afterwards.... | [
"http://en.wikipedia.org/wiki/Glasgow_Coma_Scale",
"\nThis is the GCS, and it is the standing scale for measuring unconsciousness, (although, I should mention, it has come under pressure lately, though I don't know of any other scale widely that is used at the moment.) I didn't see anything specific on the time t... | [
"Thank you, you just saved my suspension of disbelief. "
] |
[
"Why can't the Gardasil vaccine rid you of the HPV strains you have, but can give protection from the ones that you don't have?"
] | [
false
] | null | [
"Gardasil contains the major capsid protein (L1) from different HPV types. Thus, vaccination results in immunity against the viral capsid (the shell of the virus), preventing new infection with HPV. ",
"However, previous HPV infection that results in viral integration (like what would cause cervical cancer, etc) ... | [
"Is there a reason why doctors refuse to give the vaccine to people at a certain age? I'm in my 30s, and I never knew this vaccine existed. When I asked for it, my doc refused because of my age, which perplexes me."
] | [
"That's weird they refused. We give the vaccine for people up to 45 years old. The reason we don't go past 45 is that the original clinical trials were on people up to 45 years old, so we just don't have data on risks/efficacy on how the vaccine works for people older than that"
] |
[
"are fuel cells dangerous to the environment"
] | [
false
] | are fuel cells dangerous to the environment? | [
"Generally speaking, no. There are many different types of fuel cell, but the most common ones' waste products are water and heat, both of which are obviously useful and can be harnessed easily. There are hydrocarbon fuel cells which give off carbon dioxide, but these aren't very common (mainly because they're less... | [
"By themselves, no because one of the fuel cells that people like to talk about the most use hydrogen and give off water as a byproduct. The big problem is where the hydrogen comes from. You could split water into hydrogen and oxygen, but on a large scale the amount of energy needed is pretty great and that energ... | [
"thx guys "
] |
[
"Did Native Americans who lived in climates similar to Europe develop lighter skin?"
] | [
false
] | I was watching Pocahontas and this question popped into my head. | [
"No, although changes in diet may indeed have affected skin colour, it is more dependent on local environmental factors (i.e. latitude and amount of sunlight exposure) than genetic ancestry. Take a look at a ",
"map of global skin tones",
". "
] | [
"No, although changes in diet may indeed have affected skin colour, it is more dependent on local environmental factors (i.e. latitude and amount of sunlight exposure) than genetic ancestry. Take a look at a ",
"map of global skin tones",
". "
] | [
"This map seems to project skin tone onto a single dimension of light -> dark. How does it account for other variations, like \"red\" in Americas and \"yellow\" in Asia? Are these myths? (They don't seem to be from my experience.)"
] |
[
"could we take rhino reproductive dna and inject that into a horse to genetically create a unicorn?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"It is hypothetical or speculative in nature. We do not allow hypothetical questions because questions that cannot be confidently answered with any available data often invite non-scientific speculation.... | [
"understandable, but who picked that name?"
] | [
"/r/asksciencediscussion",
"? I don't know, but probably one of the askscience mods who created it."
] |
[
"Do astronauts shave in space or do they wait till they get back? Mostly they look clean shaven - so I guess yes. However, with everything in space about 16 times more complicated than back on the planet...I just wondered"
] | [
false
] | null | [
"Here is a ",
"description from the Canadian Space Agency",
"."
] | [
"I don't know if you have Netflix, but if you do, watch Part 3 of the Discovery series \"When We Left Earth.\" Go to 28 minutes in and you will see Neil Armstrong (I think, hard to tell) shaving. There's your answer. "
] | [
"That looks like a terrible shave, and besides from that, how do they stop loose bristles that doesn't get caught in the foam from floating freely about and messing up equipment or personel in the spacecraft? According to the above link",
"Astronauts shave with foam or an electric razor, but most prefer the latte... |
[
"Density and water slides"
] | [
false
] | I've got a quick question about water slides. Say there are two objects of equal dimensions. One is twice as dense as the other. Both are put on similar water slides with uniform flow. Which will reach the bottom more quickly, if either? Why? | [
"Depends on if they're thin enough to be completely submerged, on if they're dense enough to displace the depth of water on the slide, on wind, and on the coefficient of friction between the two materials and the slide material in the presence of water. ",
"Assuming the coefficient of friction is low(it's a ",
... | [
"If the water is moving faster than the boxes it could cause the less dense one to win. "
] | [
"Would the force of the moving water be factored in there at all?"
] |
[
"If a lady got pregnant by 1 identical twin, would they be able to do a paternity test to tell which twin was the father?"
] | [
false
] | [deleted] | [
"Identical twins have identical DNA. Therefore, if said paternity testing consisted of DNA testing or blood type testing, they would not be able to tell the difference"
] | [
"Try searching. In askscience this was asked ",
"3 weeks ago",
" and ",
"3 months ago",
"."
] | [
"Well, they'd have a few mutations. If you could find them you could distinguish them, but it's worse than a needle in a haystack. And then you'd need to be able to isolate the specific location, etc., etc."
] |
[
"Can we have twin planets like we have twin stars?"
] | [
false
] | How would they circle eachother and their respective star(s)? | [
"Yes. The Earth-Moon system is very close to a twin planet.",
"Luna in comparison to Earth is the second largest mass ratio in the solar system, I believe second only to Pluto/Charon. It is so large, in fact, that not only does the moon orbit the Earth, Earth orbits the moon. Their common barycenter is not the c... | [
"Another cool fact, the barycenter of the Pluto/Charon system is outside of the radius of Pluto."
] | [
"TECHNICALLY neither are planets, so not quite. But probably the closest to what the OP was asking about. "
] |
[
"How do scientists use radiocarbon dating to determine the age of Stonehenge?"
] | [
false
] | Scientists used radiocarbon dating and determined that the first stones in Stonehenge were raised around 2400 B.C. How can they use radiocarbon dating to determine this? Wouldn't it only tell you how old the stone is and not when it was put there? | [
"Very good question, as geochronological method should not date the stones themselves in this case (which by the way are, it seems, Ordovician: ",
"http://www.sciencedirect.com/science/article/pii/S0305440310003699",
" - not through C14 but through U-Pb on zircons which is the gold standard for dating igneous r... | [
"I'm just going to tack on to this comment rather than repeat most of what you just said. Another factor helping archaeologists is that people often make religious dedications when throwing up new buildings. This often involves burying some offering beneath the structure. Specifically, they've been able to date Sto... | [
"You could date the organic material which the rock was put ",
" and then date the first bits of organic material which well on the rock."
] |
[
"Do primates sense of humor?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"To check for previous similar posts, please use the subreddit search on the right, or Google site:reddit.com",
"/r/askscience",
" ",
"Also consider looking at ",
"our FAQ",
... | [
"Are you honestly telling me to use Wikipedia? Wow!"
] | [
"No, I am saying to search ",
"/r/askscience",
" in the searchbar for \"animal humor\". You will find several posts on the topic."
] |
[
"Why doesn't frozen bread get soggy when it's defrosted?"
] | [
false
] | It seems like there's moisture in the bag, but it doesn't make the bread soggy. Why? | [
"TIL what YMMV literally means, and that in the USA it's use is also idiomatic!"
] | [
"Unless it is dehydrated, all food contains some amount of water in it. When you put packaged and sealed food items in the freezer, they won't absorb any more moisture than what they already have. If it wasn't soggy when you put it in the freezer, it won't be soggy when it thaws outside the freezer."
] | [
"yeah if there isit any water added while freezing and the structure of the bread doesn't change enough to hold any less water then the feel of it should stay the same. if you had something which lost its structure for holding water when you froze it, and you defrosted that then it would feel soggy "
] |
[
"How closely could you suspend a particle anti-particle pair without having them annihilate each other?"
] | [
false
] | Obviously you couldn't get closer than the Pauli Exclusion limit, or even right up to that point, but how close could they come to each other without reacting? | [
"A ",
"positronium",
" is a system made of an electron and an anti-electron. It's not very stable and decays in less than a nanosecond, but at least it exists."
] | [
"As well as all of the mesons and specifically the states of \"quarkonium\" (up/anti-up, down/anti-down, charm/anti-charm....)"
] | [
"You actually could get as close as the Pauli Exclusion limit -- the Pauli Exclusion Principle asserts that not all the quantum numbers of two fermions can be the same. But a particle and antiparticle differ in at least one quantum number (charge or lepton number or what-have-you), so their other quantum numbers c... |
[
"I heard somewhere that if one could see the Andromeda galaxy in its entirety, it would look 2-3 times the size of the moon, is this true?"
] | [
false
] | I can't remember where I heard it, but supposedly all we are seeing when we look at it through consumer grade optics is just the bright center. Is this true? | [
"I've heard 6x as the number, but why don't we do a bit of calculation and figure it out?",
"The moon's angular size is about 32 arcminutes, which translates to roughly a half of a degree.",
"Andromeda is 2.5 million lightyears away and about 200,000 lightyears across. So its angular size if it was all visible ... | [
"Yes",
"!"
] | [
"The Moon's angular diameter is listed at ~32'",
". ",
"Andromeda is listed at 190' by 60'",
"So andromeda is about 6 times wider than the Moon, and about 2 times \"taller\"."
] |
[
"I just read that Venus has about 90 atmospheres pressure at the surface. Knowing that Venus is about the same size as Earth, how can it have such a deep, or heavy, atmosphere?"
] | [
false
] | null | [
"Lots and lots of dense gas in the atmosphere.",
"The more gas you have, the more pressure gets developed at the bottom of the \"stack\". The denser the gas (CO2 is quite a dense gas) the heavier it will be, which contributes to the pressure even more.",
"If all the gas were replaced with H2 or He, the pressure... | [
"It asks why it has such a dense or heavy atmosphere not why the dense gases came to be, but that's just semantics. I'll try to answer that.",
"Scientists theorize that there used to be liquid water on Venus a few billion years ago, and it may have even been an Earth-like planet. However, a runaway greenhouse eff... | [
"A denser core would make the planet's radius smaller for a given mass, which means that the pressure developed would be higher."
] |
[
"Is it true that the laws of thermodynamics place an upper limit on the longevity of life. If so how?"
] | [
false
] | I have heard that because the total amount of usable energy in the universe in decreasing there is no way life could last forever. Is this true and could you explain it a little more? | [
"It's all about entropy, check out ",
"Heat death of the universe",
"There is currently a lot of free energy. On earth, there are stored forms like hydrocarbons (oil), radioactive materials etc. Life is hypothesized to have been formed from pools of certain elements being struck by lightning (the energy from wh... | [
"The beautiful order and structure you see among the plants and animals on earth is what a physicist might call a relatively ",
" system (Baierlein's undergraduate thermal book has a great description of entropy, evolution, and life IYI). Low entropy systems tend to be highly structured, and high entropy systems ... | [
"What you've heard about is probably ",
"the heat death of the universe",
". The basic idea is that, according to the second law of thermodynamics, the total entropy of the universe is increasing, which means the energy in the universe is becoming more and more evenly distributed. The first law of thermodynam... |
[
"If nothing can escape a black hole how does the universe grow from a singularity of all the mass in the universe?"
] | [
false
] | Already read what wikipedia says on this. | [
"So there's a really big difference in the \"singularity\" that we say when we say a big bang and the \"singularity\" we say when we say a black hole.",
"The equation that governs General Relativity takes a distribution of mass and energy and tells you how space and time are curved around it. If you take a spheri... | [
"It's not known that there was a primordial singularity. There are models that include one and models that don't, and they're all apparently consistent. We don't yet know enough about the universe as it presently exists to unequivocally discriminate between the various models.",
"That said, if there was a primord... | [
"Believe it. Though the details are still coming into focus, it's obvious that during the inflationary period at the beginning of the Big Bang, metric expansion occurred at such a monstrous rate that the geometry of space was stretched to near-perfect flatness."
] |
[
"If the Universe is expanding, does that mean that there is a greater energy cost to move \"against the flow\"?"
] | [
false
] | Once again, reading comments in gave me a moment of slight understanding. RobotRollCall gave a good analogy here: But this made me consider that as the universe expands, it essentially changes the rules of what is allowable to occur in physics over time. i.e During the Big Bang matter could begin to form because essen... | [
"But this made me consider that as the universe expands, it essentially changes the rules of what is allowable to occur in physics over time.",
"You're sort of right, in a sense, but it's better here to say that you're actually wrong.",
"The laws of physics do not change over time. However, the laws of physics ... | [
"That's part of it. But even if we were to imagine metric expansion freezing, there would still be an eventual heat death of the universe. All the stars will burn out someday, and so on and so forth."
] | [
"If I understand you correctly, your question can be broken down into the following:",
"If you flew to the nearest galaxy twice, once now and once in a million years, would it take more energy the second time because the distance is increasing?",
"(This is ignoring the fact that some galaxies are getting closer... |
[
"Is it possible for massive amounts of water to be sucked into the Earth after an earthquake?"
] | [
false
] | What I'm really worried about is that if an Earthquake created a huge crack in the ocean, is it possible for us to lose all or most of the water? If so, how far down would the water go? Would we be able to get it back? | [
"where would it go? in short no. an earthquake wont cause the oceans to drain at all. ",
"Quite of bit of ocean water is pulled under the crust every day in subduction zones. It eventually comes back to the surface as steam from a volcano or other similar venting. "
] | [
"yea, you have to keep in mind that the Earth is really solid (minus some open spaces such as caves, or even the porosity in rocks), so there wouldn't be anywhere to store that much water. "
] | [
"In my head, I see the cracks going pretty deep into the earth. Perhaps I should've done more research. Thank you though! "
] |
[
"Is it possible to create a formula out of a series of computer generated random numbers?"
] | [
false
] | null | [
"As far as I know the randomness created by a computer is never truly random, because it is created through some kind of algorithm, isn't it?",
"Yes, that's correct.",
"Is it possible to find out by those numbers, how the algorithm that created those numbers works.",
"I don't know the answer to this question,... | [
"What do you mean?"
] | [
"If I have a series of numbers like \"1 5 35 23 9 3 6\" that was generated \"randomly\" by a computer. Is it possible to find out by those numbers, how the algorithm that created those numbers works. \nAs far as I know the randomness created by a computer is never truly random, because it is created through some ki... |
[
"What geological/mechanical forces are represented in this perfect road split?"
] | [
false
] | I'm curious why it does this. A civil engineer weighed in at the original thread and we still didn't really reach a conclusion. Is it just coincidence that the split is so perfect so far down? Is the image a really good fake? (Doesn't seem likely, as I have seen a lot of shops in my time). | [
"It appears to me that this is the result of shearing perhaps. I would like you to take note of where in the foreground, the very bottom of the picture, where the left side appears to buckle up higher than the right side.",
"I would also like to say that it is most likely not so perfect a split as this particular... | [
"My guess is that perhaps the two lanes were laid separately creating a weak point where the two roads met in the middle which sheared under the pressure of the earth quake. "
] | [
"I second this, if you see the way roads are originally paved the machines pave a lane at a time for convenience's sake. An earthquake could've caused some of the bedrock to sheer away and lift one lane section of the road up, appearing to make a very straight cut. "
] |
[
"How does rayleigh scattering polarize light?"
] | [
false
] | As far as I understand, the light from the sun is scattered with a bias towards certain polarization angles. But, the sunlight is randomly polarized and the molecules in the air are randomly oriented, so how does this bias come about? | [
"The polarization of sunlight (the blue sky) relies on three things:",
"So, given all that, if you look just a bit to the side of the Sun, say a few finger widths away, you're looking at molecules that are shaking roughly equally in all directions perpendicular to your line of sight, and light you see is basicall... | [
"The light that reaches you is partially polarized by this effect; how polarized depends on the angle you're looking at, ie what angle the light had to scatter through to reach you. ",
"Looking at the light coming into the atmosphere, yes, there is equal amounts of scattering for the different linear polarizat... | [
"Would it be correct to say that the light that reaches me has a polarization bias. But in general, the light scattered in the atmosphere is polarized in uniformly random directions?"
] |
[
"Was always warned to stay away from windows and off/away from electronic devices (television, computer) during a thunderstorm. How valid is this claim, and how dangerous is it really?"
] | [
false
] | null | [
"Mythbusters tested this. If you have Netflix then you can watch it. It's the episode \"Son of a Gun\" (s01e11).",
"The phone did allow the current to go through (if the fuse wasn't grounded) and it would have killed someone.",
"They also tested if someone was in the shower \"as if they were standing on a drain... | [
"So, if there's no surge protection on between the power lines feeding your home, and the consumer electronics are plugged into the wall, a major surge can damage your electronics by briefly exposing them to currents and voltages well outside their operating ranges. If the surge is say a lightning bolt hitting a po... | [
"A ",
" phone would carry a current, you've essentially got a circuit directly connected to the physical phone lines. A ",
" home phone or a mobile phone shouldn't shock you, unless something else is horribly wrong with it.",
"And, ok, don't take showers, don't wash the dishes, etc... But I feel like the grou... |
[
"Why is New Horizons going to flyby around Pluto and not orbit it?"
] | [
false
] | I read on Bad Astronomer's (Phil Plait) blog that New Horizons won't be passing by the side with 4 parallel dark spots. With all these exciting stuff coming in daily, I am more curious than ever to know more about it. | [
"Basically, in order to orbit Pluto it would have to massively slow down, and to do that it would have to burn a lot of rocket fuel, and it is simply not feasible for it to carry that much fuel."
] | [
"That's true, but there's a limit to that, and that limit is the ground.",
"To be less flippant, let's do the math:",
"Pluto has a mass of 1.31e22 kg and a radius of 1.18e6 m.",
"Escape velocity v = sqrt(2GM/r) so v = sqrt(2*6.67e-11*1.31e22/1.18e6) = 1.21 km/s",
"As long as the probe is travelling faster t... | [
"Exactly. Apparently the probe would need the equivalent of its lift rocket (the Atlas V) to put it in orbit "
] |
[
"Why is freshly fallen snow more \"packable\" than older snow that's been on the ground for a while?"
] | [
false
] | when snow has been on the ground for a while, it becomes more powdery and less able to be packed into snowballs. I just don't understand why. I know that when the snow is slightly melting, it's easier to pack snow because of the surface tension with the melt-water, but it doesn't feel the same when you're packing it as... | [
"You're already onto the basics of packing snow - how wet it is matters a lot.",
"If snow just sits on the ground for a while, several things can happen to it. The water can freeze, and melt again, and freeze again, and so forth. This plays havoc with \"wetness\" and \"snowness\", and it's next to impossible to g... | [
"It depends on the snow, some fresh snow is extremely low in moisture (little cottonwood canyon, I'm looking in your direction) and some is very \"wet\" ( AKA Sierra Cement) the humidity and air temperature, wind, and so on will affect how much moisture is pulled out of the snow after it has fallen, or how much is ... | [
"Wait, what? I can make killer snow balls the day after a snowfall because the snow packs so tightly. During a fresh fall, the snow is like trying to pack Splenda into a snow ball (perfect example if you've ever used it). ",
"Maybe Ohio is just weird, but I swear this is backwards. As teenagers, all of us would w... |
[
"Why is mars so cold,-63 C, when its atmosphere is 95.3% CO2, which is considered a green house gas?"
] | [
false
] | Facts found at Edit: "Thanks Reddit" | [
"Mars' atmosphere might be mostly CO2, but it's still an extremely thin atmosphere compared to Earth's, not to mention Venus'. If you check the surface atmospheric pressure, you'll see that it's about 6 millibar, which is 0.6% of Earth standard atmospheric pressure. This is very tenuous, and not nearly enough to ke... | [
"Artificial structures would be necessary to live on Mars for reasons of temperature and pressure, and sometimes radiation threat from the Sun.",
"The arguments for going to Mars are varied, but mostly can be summarized as belonging to one of two camps: First, we shouldn't keep all of our eggs in one cosmic baske... | [
"While the points you make are by far the most salient, I think it's worth noting that water vapor is the most powerful of all greenhouse gases. ",
"The Earth's troposphere contains between 0.1% and 4.24% water vapor (depending on location and weather) while Mars' atmosphere contains (according to my quick calcu... |
[
"How can someone pull a plane/train with only his teeth? And even with his only strength?"
] | [
false
] | null | [
"Wheels make things very easy to move, the object may weigh several tons but because of the wheels he doesn't actually need to ",
" it, just get it rolling. "
] | [
"Any relatively strong person can, try setting your car into neutral somewhere flat and give it a push. You'll find it's pretty easy to move it around even though it weighs 1000-2000lb. "
] | [
"Train wheels are at an angle so that they can go around turns"
] |
[
"How fast are we really moving through the universe"
] | [
false
] | Relative to other galaxies or all galaxies together how fast are we moving? For example, the earth is rotating at the equator at 1670 km/h. We are orbiting the sun at a certain speed. The sun and our solar system is orbiting the center of the galaxy. And our galaxy is moving relative to other galaxies. So do we know ho... | [
"There is no objective answer to this. Motion can only be defined in relative terms -- you can ask how quickly the Earth is moving relative to another star or galaxy or supercluster, but the question of how fast Earth is moving through \"space\" is not one that is coherent in our current understanding of the univer... | [
"This is why I've said for years that all time-machines must also be space ships.",
"Even if you travel one second into the past or the future - the Earth isn't going to be where you left it."
] | [
"Yes. Mastery over time requires a mastery over space as well."
] |
[
"Do mirrors have \"focal lengths\"?"
] | [
false
] | I don't know how to put it better than asking if mirrors also can have different "focal lengths" like lenses – in some mirrors my face looks a bit wider, as if the mirror was a bit more wide angled, and sometimes it looks a bit narrower, as if my face was seen through a tele lens. | [
"You can also say that a flat mirror has an infinite focal length to generalize the definition; this is how it is treated in optics."
] | [
"TL:DR Sometimes.",
"A focal length is the distance between the lens, or in this case the mirror, and where the reflected or refracted light converges. In other words, after interacting with the object, where does all of the light join up. In a plane (flat) mirror, the light never converges but if the mirror is c... | [
"Mirrors do have focal lengths. You can think of a mirror as a lens that revert the direction in which light travels. The mirror inside your car that allows you to look behind the car (I don't know the term sorry) is curved inward to magnify a bit the image. It then looks like something is slightly closer/bigger th... |
[
"Question about the big bang and dark matter/energy."
] | [
false
] | I read on wikipedia that the Big Bang started with an extremely hot and dense state. Given the new understandings of dark matter and dark energy that seems to give the universe a total energy of zero, does this require that the initial state was still extremely hot and dense or could the initial state be an unstable, c... | [
"Dark matter and dark energy are not 'negative matter' or 'negative energy'. The energy content of the universe is not necessarily zero."
] | [
"Could you quote a source for that statement? ",
"I'm operating under the assumption that our best model for the large scale structure of the universe is the Friedmann-Lemaître-Robertson-Walker model. In order to have a flat universe, the ",
"density parameter",
" of this model needs to be 1, which correspond... | [
"ICWYDT",
"If one assumes that the total energy in the universe is zero, then there would have to be a way of having negative energy to balance all of the positive energy we observe (normal matter, dark energy, dark matter). The best theory I have seen is that you can write the expansion of space-time as being du... |
[
"For exoplanets to be discovered using transit photometry, do they have to be in line with earth(does the planet have to pass between earth and its star)? If so, does this mean that planets that orbit in a plane where they don't pass between the earth and its star are undetectable?"
] | [
false
] | null | [
"Yes, the transiting planet should more or less pass between the our telescopes and the star, which of course is a limitation. ",
"There are some alternatives that do not require the planet's plane to intersect our line of sight, such as Astrometry. It involves measuring the wobble of the star as the planet orbit... | [
"You're right that this technique works far better when the orbiting planet is fairly massive, which is obviously a limitation, but it should still be possible to detect an earth sized planet.",
"The amplitude of the stars wobble is proportional to the ratio of the planet's mass to the star's mass, so an earth si... | [
"Is it possible to detect Earth sized planets with this method? It seems like a planet would need to be huge in order to cause a noticeable effect on the parent star. "
] |
[
"How are false positive lateral flow tests possible?"
] | [
false
] | null | [
"Lateral flow tests typically use an antibody with an affinity for some target molecule (the virus fragments in this case), but there is always a non-zero probability that some other molecule will bind to and activate the antibody. Many drugs work by fooling a protein in the body to activate as if it was in contac... | [
"It's very possible. I'm a lateral flow assay developer - we are currently developing a number of LFAs for COID-19. As fossiliz3d said, false-positives and false negatives are a an inherent risk. There is always going to be a tradeoff balance sensitivity and specificity. While the antibodies themselves might good, ... | [
"It's very possible. I'm a lateral flow assay developer - we are currently developing a number of LFAs for COID-19. As fossiliz3d said, false-positives and false negatives are a an inherent risk. There is always going to be a tradeoff balance sensitivity and specificity. While the antibodies themselves might good, ... |
[
"Are there any two foods/edible materials that are harmless when consumed separately and dangerous when consumed together?"
] | [
false
] | This was somewhat inspired by a friend's belief that she would explode if she ate Mentos and Diet Coke in quick succession. Having empirically showed that this is untrue, are there any foods/drinks/other materials which are safe to consume on their own, but would have side effects if consumed together? | [
"God damn it, My apologies."
] | [
"Downvoted, but only because you mixed up nitrates and nitrites. It's nitrites that form nitrosamines in the presence of protein and acid, and any acid will do, including stomach acid.",
"http://en.wikipedia.org/wiki/Nitrosamine"
] | [
"Downvoted, but only because you mixed up nitrates and nitrites. It's nitrites that form nitrosamines in the presence of protein and acid, and any acid will do, including stomach acid.",
"http://en.wikipedia.org/wiki/Nitrosamine"
] |
[
"What happens if water vapor is compressed while kept at a temperature greater than 100 degrees Celsius? Can it turn into liquid form?"
] | [
false
] | Sorry if this is a dumb question. | [
"Yes, it can. The boiling point of water is only 100 deg. C at a pressure of 1 atmosphere. At lower pressures the boiling temperature is lower and at higher pressures the boiling point is higher. You may have experienced this if you've ever gone camping at high elevations. You often have to put salt in the wate... | [
"Yes, you can up to a certain temperature. To see that, take a look at the phase diagram of water ",
"here",
". So for instance at 400K (about 130C), if you draw a vertical line going upwards (if you raise the pressure at a fixed temperature), at a certain point you cross into a region where the liquid phase i... | [
"I forgot about the fact that boiling and freezing points are not fixed in relationship with pressure, it makes much more sense now! "
] |
[
"I have a PCL tear which never healed properly. It hurts more during the winter (New England). Is there a physiological explanation for this, or is it just my subjective interpretation?"
] | [
false
] | [deleted] | [
"I have a suspicion for this phenomenon, but it's only a hypothesis. I do not study this and this is just conjecture. Someone who knows better feel free to correct me.",
"Anyways, when you get an injury or tear to tissue, there are two healing process, both very separate from each other. The first is regeneration... | [
"Based on my \"gut feelings\", I really like your source material (scar vs. healthy), but would like to not rule out what AnatomyGuy mentioned as a potential catalyst to the phenomenon. Barometric pressure. My gut tells me that might have more to do with it (maybe the cells expand and contract at different pre... | [
"Hmm...this...could be possible. The problem is we have to consider what would change when pressure changes. Typically, fluid and solids (i.e. water and collagen) are considered incompressible. That would suggest that the neither the cells, or the tissue as a whole would change size in a changing pressure.",
"How... |
[
"How much CO2 do volcano's really expel on average per year, and how does that amount compare to man-made emissions?"
] | [
false
] | I get 300 million tonnes here : and less than half that here: What is a reliable source? It's popular myth in the Australian right wing media that volcano's emit much more carbon dioxide than humans, which is in turn used to discredit the scientific consensus on climate change. I'm looking for sources with the most s... | [
"It's kind of irrelevant, because as you can see here (",
"http://cdiac.ornl.gov/ftp/ndp030/CSV-FILES/",
") the total estimated number of metric tonnes of CO2 caused by fuel burning is around a stately 8000 million each year. "
] | [
"The truth is, it's hard to know exactly how much CO2 is coming out of volcanoes. You can measure the rate coming out of fumaroles and then integrate the amount coming out of soil diffusion, but then there's all the undersea volcanoes that we can't measure! That's why the number varies so much. As for an actual val... | [
"The argument presented doesn't really make any sense, because even if man-made contributions were dwarfed by volcanic CO2 emissions, the additional carbon from human activity would still be adding to the total, and could therefore still be sufficient to push the system over a \"tipping point\" into a new equilibri... |
[
"Why does an electron and a proton have the same magnitude of charge even though the electron is a lot smaller than the proton?"
] | [
false
] | [deleted] | [
"A proton is a composite particle made up of 3 valence quarks and many many more \"sea quarks\" and gluons. The charges of sea quarks cancel because there are as many sea antiquarks as there are sea quarks for any given flavor. The gluons carry no charge. So all of the charge of the proton comes from the three vale... | [
"Are the \"sea quarks\" virtual particles or real?"
] | [
"Virtual. Constantly being pair-produced from gluons and annihilating back into gluons. \nGreat question."
] |
[
"What is the connection between nosebleeding and time traveling as seen on movies ?"
] | [
false
] | null | [
"It's made up because there is no such thing as time travel"
] | [
"Maybe there is but all nosebleeding stories are made up ?"
] | [
"There isn't and those are just movies. It's like saying most aliens in movies are depicted as green and tall and skinny so maybe they really are."
] |
[
"Is there a reason we sent the Voyager craft ahead of the solar system/into the bow shock of the heliosphere?"
] | [
false
] | Pretty much what it says in the title. Why that way instead of "behind" us, isn't there much there or was having instruments in the bow shock more worthwhile? | [
"When the voyager space craft were launched the planets in the outer solar system were in positions that allowed a single mission to do flybys of several different planets. The 2 voyager spacecraft were launched to take advantage of this, but the route they took meant that after the planetary flybys they would con... | [
"blobhopper's post is correct. Voyager I was launched on a trajectory that would let it observe Jupiter and Saturn, and that restricted the direction of its eventual, permanent flight path.",
"If we ",
" been able to pick a direction to investigate the heliopause, we would have chosen the direction of the theor... | [
"Ahhhhhh ok then, thank you"
] |
[
"Is it possible to use a set of units for measurement (length, time etc.) that would negate the need for universal constants?"
] | [
false
] | We currently define a meter as a set certain length, and a second as a set certain amount of time. This means in formula like the law of gravity, we must use the Gravitational constant to make the math work. If we had different definitions for mass, length and time etc. then this constant would also be different. So co... | [
"The Planck units do this.",
"There is still some room for interpretation over which equations you shrink and which constants you eliminate. For example, in the Planck units, Coulomb's law has no constant, but the unit for charge is not an integer multiple of the fundamental charge.",
"The Planck units are also... | [
"No. We can eliminate many of them using the Planck units, but there's nothing we can do about ",
"dimensionless physical constants",
". For example, the fine structure constant is about 1/137. It's not 1/137th of a meter or something. Just 1/137. It doesn't matter what system of units you use, because there's ... | [
"Cheers for the answer"
] |
[
"Is it possible to generate propulsion of a wavelength using a laser?"
] | [
false
] | [deleted] | [
"I don't understand the question. A \"wavelength\" is not an object, it is a property of something. You can create light at a certain wavelength. You can use a laser to create light at a certain wavelength.",
"Also, I don't know what you mean by \"a laser doesn't technically disturb the wavelengths around it\"... | [
"A wavelength isn't an object, it's a size. How do you push a size?"
] | [
"In general, photons don't interact. Unless they're high energy ones in which case they can interact to pair produce particles and anti-particles."
] |
[
"FTL Communication"
] | [
false
] | Hypothetical time! Say I built a gigantic, gigantic building - I'm talking reaching into space tall. In that building I have a long rod that goes from the top to the bottom. If I tapped the rod at the bottom level, would the top of the rod instantly move up (presuming the strength to move such a rod)? Could I use a lot... | [
"Mechanical signals travel at the speed of sound. For wood, this is a few kilometers per second."
] | [
"This question is asked pretty often around here. Check out ",
"this entry",
" in ",
"/r/sciencefaqs",
" and see if that answers your question. "
] | [
"Thank you."
] |
[
"Illustrations of dinosaurs often depict volcanoes in the background. Were erupting volcanoes once so common that this a probable scene if one were to look at a typical dinosaur during its era, or is this a cliche that's an artifact of compressing our perception of extremely long time-scales?"
] | [
false
] | null | [
"It is just dramatic effect.",
"Science often describes the effects of increased volcanism, in the Jurassic for example, and this is certainly part of what you describe. There are theories about geology, and the breakup of supercontinents, ",
"Associated middle to late Jurassic volcanism and extension in south... | [
"There's also the hypothesis that a supervolcano (like the one beneath yellowstone national park) was the cause or a significant contributor to the extinction of dinosaurs. "
] | [
"I think you're talking about the eruption of the Deccan Traps, which happened around the end of the Cretaceous. Here's the ",
"wikipedia",
" page for it, but if you want a pretty good description of its effects on the climate (and life on earth at that time), I think ",
" by David Beerling actually did a re... |
[
"How are the effects of molecules' spatial orientation on reaction kinetics studied?"
] | [
false
] | In general chemistry I recall learning that certain spatial orientations of molecules are more favorable for producing a reaction than others. Presumably when two molecules, A and B, are approaching, it is more favorable if the reacting group of A is oriented towards B and vice-versa, rather than the reacting groups b... | [
"You are asking about the Frequency Factor, specifically one component of that which is the Orientation Factor. OK, let's back up:",
"We're talking about Collision Theory for chemical kinetics, where the rate constant (k) is described via the ",
"Arrhenius Equation",
":",
"In this equation A is the Frequenc... | [
"Lyotropic Nematic and Lamellar liquid crystals may be used to study orientation effects on certain reactions, see- V. Ramesh and M.M. Labes Journal of the American Chemical Soc. vol 109,3228 (1987) ,ibid Vol.108, 4643 (1986).",
"Reactions at monolayer surfaces are discussed by H. Kuhn in Modern Trends of Collo... | [
"Are molecular beams of any value here? Is there any way to control the orientation of a beam of molecules using such technology? I am totally speculating here, but would an electric field applied to the beam orient the molecules in a particular way, making that parameter a known experimental quantity? Would thi... |
[
"Followup to: What is the distribution of numbers picked at random by people?"
] | [
false
] | Original thread by iamayam . Gist of the question: I want each person in a large group of, let's say, 50 people to choose a number from 1 to 4. Each person picks his/her number silently, so that no one else knows who has what number. What is the likely distribution of those picking 1, 2, 3, or 4? I then made a quick . ... | [
"There's something in game theory call a beauty contest, where you tell people to pick a number between 1 and 100 and that a prize will be awarded to whomever picks closest to two thirds of the average of all the numbers. If you assume everyone is an idiot and guesses randomly then the average should be about 50 an... | [
"EDIT:\nAs nicksauce incorrect analysis is still getting upvoted, I guess I didn't explain myself properly, so I've expanded my explanation significantly.",
"Nicksauce doesn't factor in the number of bins (4 bins as 4 numbers you can guess). If there were 16 bins and 64 total votes, he'd still say there is a 12.... | [
"First, method was flawed by letting people see poll results prior to the poll being concluded. (E.g., one could vote multiple times to twist the dataset).",
"Second, with 64 #s you may ask what percentage of the time do you get a # less than or equal to 9 from a uniform distribution? A quick Monte Carlo shows ... |
[
"What factors affect the rate in which marijuana metabolites are excreted from the human body?"
] | [
false
] | [deleted] | [
"Unsurprisingly, it's metabolism and excretion (peeing/sweating/etc). You need to increase your metabolism to burn the fat cells which contain the metabolites, and then you need plenty of water to flush the released metabolites from your system. ",
"If you're looking to get rid of the most metabolites as fast as ... | [
"Sorry didn't realise."
] | [
"Nope. The relevant information would be some crazy cellular analysis, not mention require some metabolic tests, assuming you want the information to be accurate to your unique situation. No \"guide\" or anything will tell you exactly how to calculate it for yourself. It's so highly depending on so many unique fact... |
[
"Which has more complexity as far as the number of physical operations happening in one time, a 200 foot commercial fishing vessel (minus crew) or a single celled organism?"
] | [
false
] | I'm sitting on my boat in the Bering Sea, thinking about what defines life (we do a lot of philosophical thinking out here) and if you could say that the boat is alive. I mean power is created by burning energy, there are a huge number of computers, transformers, fans, pumps, winches, even the two sets of washers/dryer... | [
"I don't know much at all about boats, but I feel pretty confident saying its a single celled organism, and I'll try to explain why. Proteins are created from a DNA template in two steps. First, the DNA is ",
"transcribed",
" into mRNA. Then, the mRNA is ",
"translated",
" into a protein by a package of pro... | [
"Snarky: The boat is clearly more complex, since it contains at least one cell of cyanobacteria, as well as other stuff.",
"Not-snarky: Presumably there is some implicit feature size - where the questioner would say \"that's not my boat, that's the natural microcrystalline structure of steel\" or \"that's not my ... | [
"I don't think it's fair to count the sub-processes of one body and not the other. You could count the the combustion of all the fuel molecules and every stroke of a mop and get quite far with the ship's count as well. Then again, what level organization and indeed what organization at all would offer a fair compar... |
[
"What causes people to procrastinate and what do you have to change to stop it?"
] | [
false
] | A lot of people procrastinate. I'm an expert at it. I'm trying to figure out the underlying causes of it, both biologically and psychologically. What can one do to actively stop it from happening permanently? | [
"Check out ",
"temporal motivation theory",
", which outlines four factors in determining motivation at any given time: expectancy, value, impulsiveness, and delay. The rationale for those factors make intuitive sense:",
"Expectancy: if you expect to succeed in a task you'll be more motivated to do it - e.g.,... | [
"Check out temporal motivation theory[1] , which outlines four factors in determining motivation at any given time: expectancy, value, impulsiveness, and delay",
"Sounds really interesting. I'll check it out tomorrow or whenever I get around to it..."
] | [
"There are many explanations for why people procrastinate, from the relative value of things now vs. in the future, to the meaning success (or failure) might hold for a person. ",
"Some possible avenues for reducing procrastination are ",
"temptation bundling",
", cognitive-behavioral therapy, or time manage... |
[
"What is actually going on when you have a \"crick\" in your neck?"
] | [
false
] | What is happening physiologically that causes that feeling of stiffness/soreness in one's neck? | [
"Some of the muscles around the neck or shoulder area have become tight and shortened so that there is no longer enough space in the neck for the vertebrae to turn freely. There are endless different factors that can cause the muscles to shorten."
] | [
"Yeah, that makes sense aye! I don't have one at the moment, I was just curious about it in general.",
"Thanks!"
] | [
"Yeah, that makes sense aye! I don't have one at the moment, I was just curious about it in general.",
"Thanks!"
] |
[
"Would a rainbow on a planet that orbits a different colored star have a different hue?"
] | [
false
] | Edit: it should be range of colors instead of hue | [
"A rainbow doesn't have a single hue, so it doesn't make much sense to say that it would have a different or similar hue. However, let's assume you can still see the same visible range of light but were on a planet orbiting a red star. Since a star is basically a giant blackbody, the star would still emit some non-... | [
"If wavelengths of light are absent from the spectrum of the star, then they will be absent from the rainbow. The rainbow's colors come from refraction, due to bending of light at the surfaces of water droplets. Our sun's peak intensity is roughly in the middle of the visible spectrum, so we get very nice complet... | [
"Light from a source, most sources at least, comes in many different wavelengths, different colors. The light from each star would be different depending on the temperature of that start. OK? ",
"So from the Sun we get different amounts of energy at different wavelengths, from infrared to ultraviolet. We see a se... |
[
"Question about Apoptosis in Heart. Your response is highly appreciated!"
] | [
false
] | [deleted] | [
"Apoptosis is a series of events not an instantaneous change in a cell. It takes a surprisingly long amount of time to occur. See ",
"Suzuki et al (2001)",
" for an example in rat cardiomyocytes. DNA fragmentation peaked at 14 hours in that study."
] | [
"Thanks for your reply. However I dont know what exactly does bolded statement mean in relation to study."
] | [
"Arrhythmia can persist for a long period of time. Like days, weeks, etc. "
] |
[
"Why does magnetism not appear on electromagnetic spectrum?"
] | [
false
] | [deleted] | [
"The electromagnetic spectrum simply isn't measuring on a scale that magnetism should appear on, any more than magnetism should appear on the top 100 schools by grades list.",
"All electromagnetic waves are ultimately composed of little energy bundles called photons, which exhibit both wave-like and particle-like... | [
"The electromagnetic spectrum describes the frequency of ",
"electromagnetic radiation",
". Electricity and magnetism are interacting phenomena which produce electromagnetic radiation. What you're asking is a similar question to 'what colour is a photon'."
] | [
"To expand on what OrbitalPete said, we know this because the speed of light is calculated to be 1 over the square root of the permeability of free space (magnetism) multiplied by the permittivity of free space (electrostatics): ",
"c = 1 / (√µ(naught)ε(naught))\n",
"This shows how magnetism and electrostatic... |
[
"Most of the world's gold is found in sea-water, is it possible to extract this?"
] | [
false
] | Could you use Electrolysis to extract gold atoms? * Tuning the Electrolysis-apparatus to the frequency, to which Gold clings to Cathodes or Anodes. * Placing these gold-extractors on oil-rigs or ships. * Taking the power for the Electrolysis-apparatus from solar, wind and wave energy-sources. Is this possible or is it... | [
"There are ",
"several ways",
" to extract gold from seawater; I'm not sure about electroysis, though. The problem is that none of those methods are currently economically feasible - they all require vast expenditures of energy to obtain a minute amount of gold."
] | [
"It is possible to extract gold from seawater. People are unlikely to do it as the cost and the energy needed far exceeds the amount of gold they receive."
] | [
" especially since these might be gold atoms. Gold by itself is a remarkably unreactive metal, the only solution known to dissolve gold is a concentrated solution of HCl and HNO3, also known as Aqua Regia (royal water). In order to get the atoms, I think Haber's idea might be effective but you would have to centrif... |
[
"How is the shingles vaccine any different from the chicken pox/VZV vaccine? Is it any different?"
] | [
false
] | null | [
"They’re very different currently. ",
"The chicken-pox vaccine is a live attenuated virus vaccine, described ",
"here",
":",
"VARIVAX [Varicella Virus Vaccine Live] is a preparation of the Oka/Merck strain of live, attenuated varicella virus. The virus was initially obtained from a child with wild-type vari... | [
"I'm 37 and had Shingles, was not fun. Doctor said no Shingrex till I'm 50 unless I get single a few more times. Why is 50 the magic age?"
] | [
"The one thing I'm aware of is the older you are, approximately 60+, there is a greater possibility following shingles of neuralgia. The nerves infected by the virus remain extra sensitive to stimulation and are exceptionally painful. My FIL at 73 had shingles, and it affected the nerve on his nose and forehead. Af... |
[
"Why does time dilation occur when traveling at near light-speed?"
] | [
false
] | null | [
"Time dilation follows directly from the constancy of the speed of light from all reference frames. I.e. if light appeared to travel faster or slower depending on how fast you were travelling, then there would be no time dilation. It really boils down to the tact that we observe A, therefore B must occur."
] | [
"It is a logical consequence of the constancy of the speed of light. ",
"If you stand near some train tracks and see Michael Jordan riding a train toward you, when he tosses a basketball at you, the two of you will disagree on the speed of the basketball. ",
"Yet if he shines a laser pointer at you, the two of ... | [
"Let's give a view from from the view of conserving \"some quantity\". Let's discuss \"Euclidean three space\" (just \"ordinary space\" you are used to). You would say, it makes no sense that an object's length, width, or depth has, in this space a (line) length is conserved, and is written as \"(length)",
" = x"... |
[
"How does heat dissipate in solid materials? Does it move away from gravity like hot air, or uniformly outwards?"
] | [
false
] | Bonus question: What decides the speed of dissipation in a material? | [
"The key word to learning more about this subject is \"heat transfer\". ",
"The laws of thermodynamics (and physics) determine how it behaves. ",
"Hot air moves around due to convection currents. The different buoyancy of hot air to cold air causes this circulation. This cannot occur in solids, since the cold/h... | [
"Thanks for that ",
" answer. But one thing seems strange to me: If heat is vibrations, why does it travel slower than macro-level vibrations (ie. sound) through that material? Is heat really vibrations in the same sense?"
] | [
"Sound works like a wave. It ripples quickly through mediums because it doesn't leave much behind, One molecule whacks another and all the energy is transferred (most). Heat (molecular vibrations), leaves energy behind when it travels. The vibrations are not like a sound wave, they're much 'finer', so when you pres... |
[
"How do handheld police radar guns work while the operator is driving?"
] | [
false
] | I'm assuming they need to be synced with sensors on the patrol car and add the relative velocity between the patrol car and the target car to compute the actual speed of the target car? Also, some guy on Youtube was saying that you could aim a standalone radar gun at the interior of your own car and somehow measure you... | [
"EDIT: and I just noticed you said \"handheld.\" I don't think most handheld radar guns have a \"moving radar\" mode, the technique I describe is used by dash-mounted speed radars, which seem to be getting more common in police use anyway. I don't think there's any reason it *couldn't* be built into a handheld rada... | [
"For lidar it seems like a mems accelerometer + GPS through a kalman filter really isn't that hard."
] | [
"I don't know exactly how radar guns work but I imagine using it in the car would be as simple as the officer driving the speed limit and measuring the relative velocity of the target car to determine how much above or below the speed limit the target car is.",
"It's technologically possible for a radar gun to me... |
[
"Why is the speed of light so important?"
] | [
false
] | I understand E=MC and why you can't go faster than C. But why is it C in that equation, and not some other number/speed? | [
"The easiest answer for that kind of question is to read the ",
"derivation",
" of the expression in question."
] | [
"It's not that the speed of light is important, but more that the 'natural' unit for velocity is ",
"."
] | [
"It's a human conceptual problem. ",
"If you had grown up with C being randomly assigned to a different number, perhaps you would ask the same question. "
] |
[
"how \"hazardous\" are the chemicals used in zara clothing that the current green peace campaign is aimed at removing?"
] | [
false
] | null | [
"The answer is that they aren't.",
"The chemicals they found on the clothing are not hazardous, they're widely used plasticizers found in many synthetic fabrics. Probably wouldn't want to chug a bottle, but they aren't harmful in clothing. Greenpeace is concerned that these chemicals, after being dumped ",
" wi... | [
"thanks, this is what I thought. It is LOW concentrations. But i am not a chemist/bio-chemist/medic, and a buddy of mine is convinced that it could be harmful to people wearing the fabrics. "
] | [
"Ignore Greenpeace, they are more about violent political action than a source of consumer aid."
] |
[
"South-west Astrakhan, Russia, has some interesting geographical features I've never seen before. Is there a name for this phenomenon, and how is it formed?"
] | [
false
] | Was just looking around on Google Maps when I came upon Tried to look up information about it but couldn't really find anything. It can be found at . | [
"These are referred to as \"Baers Mounds\" or \"Baers Knolls\" after the scientist who first described them in detail in the mid 1800's. There have been a large number of hypotheses put forward to explain their formation, with aeolian (wind blown sediment) being one of the more popular as they do have a similar for... | [
"Thank you for answering! It's pretty fascinating that it's still sort of a mystery. The longitudinal (?) striations are quite striking and I thought my browser had glitched when I saw it at first."
] | [
"This has a similar feel to it as the Carcross Desert and the Athabasca Sand Dunes (among others in Northern Canada)",
"https://en.wikipedia.org/wiki/Carcross_Desert"
] |
[
"What about quantum chromodynamics? Is this theory still around today?"
] | [
false
] | [deleted] | [
"That's literally all I study. ",
"Edit: But they're all just different names for the same thing. The strong force is one aspect of QCD, and color charge is another aspect of it. In general, though the whole theory is QCD. When we do some numerical simulations (since it's bloody difficult to actually solve), it s... | [
"Yeah I realized that after I made my initial post of one sentence. Yes, color force is still used within the field. But usually (from my experience at least) if someone says something like \"color force\" they mean something akin to the electric force, and then there's a \"color magnetic force\" the force from col... | [
"OP is asking about the terminology more than the theory. Of the terms in the OP's post I see \"strong force\", \"quantum chromodynamics\", \"strong interaction\", and \"color charge\" (my addition) used frequently. I see the term \"color force\" used infrequently. Does that accurately reflect the current trends?"... |
[
"What would we see with the naked eye if Betelgeuse were to Supernova?"
] | [
false
] | With the recent dimming of Betelgeuse and speculation that it might go supernova, I'm curious what one would see looking up at the sky with the naked eye? Would we just see brightness or could we make out the bubble from the expanding gas? How quickly would such a nebula form, and on what sort of time scale? | [
"You would see a very bright star.",
"The nebula would form pretty quickly, but it would be long, long time before you would be able to perceive it even theoretically with the naked eye, as it would have to be at least a few lightyears across to appear large enough in the sky to be resolved by your eye.",
"How ... | [
"You would just see Betelgeuse gradually get brighter for a few weeks until it is as bright as the full Moon, and then gradually get dimmer over a span of months until it disappears from the sky. It would never look like more than a very bright star to the naked eye."
] | [
"A week ago someone estimated that Betelgeuse's nebula will become too dim for the naked eye after just a year or so. 5% the diameter of the Moon would be 0.25 light years or so, at 2% the speed of light that needs 10-15 years. Bad luck."
] |
[
"Can a geneticist or a bio-chemist walk us through the differences between genomes, proteomes, transcriptomes etc?"
] | [
false
] | Additional explanations on how these different classes of chemicals interact would be welcome too! (fyi i have taken a bio-101 course in uni so I don't know much more than that) | [
"Simple answer:",
"The relationship between these three things is fairly straightforward, though as with everything in biology there are exceptions to ",
" I’m about to make. I won’t go into those exceptions here, as it’ll make the explanation into a textbook :D.",
"Every cell in an organism contains the sam... | [
"Good point - I should have said \"",
" genes are protein-coding genes...\""
] | [
"That's fine, but if every time a layperson asks this type of question and gets a severely watered-down answer like \"genes code for proteins,\" public understanding of modern research will never improve. ",
"It's like saying every body that orbits the sun is a planet. Why can't we be more specific? We can give a... |
[
"Why isn't the Winter Solstice the coldest day of the year?"
] | [
false
] | If the Winter Solstice has the least amount of direct sunlight, then why is it typically warmer than say, January or February? | [
"A lot of variables control temperature. Different air masses, cloud cover, and wind mixing are just as important to regulating temperature as radiative heating is. ",
"Assuming a constant air mass, a noticeable time lag in the global radiative heating balance appears. As summer progresses, more heat is enteri... | [
"Why isn't my drink instantly cold when I put it in the fridge?"
] | [
"Wow, that was fast. Thank you, this question popped in my head at the bar last night and sadly we did not have a Atmospheric Science/Forecast Meteorology expert to help. "
] |
[
"Suppose instead of a giant pool, the Olympic swimmers had their individual lanes of water seperated from each other. Would this affect their swimming, and if so by how much?"
] | [
false
] | null | [
"One of the issues in a giant pool is that backwash off of the side creates more turbulent water for the swimmers on the sides of the pool as opposed to the swimmers in the middle (this is why swimmers with the fastest heat times are placed in the middle; kind of a \"seeding\" of sorts). This does slow the outside ... | [
"Can anyone explain the 'riding the wave' lore that exists within swimming? That seems to have some advantage.",
"Look at ",
"this video of Jason Lezak",
" where he is actively swimming as close to his opponent's wake as possible."
] | [
"I can't speak quantitatively, however there are a few effects at play:",
"Lane lines (the floating dividers) significantly absorb the wakes from the swimmers, reducing the amount of turbulence each swimmer sees.",
"Hard walls reflect the wake, increasing the turbulence seen. ",
"Heats are populated with th... |
[
"How effective are programs like Fold at Home?"
] | [
false
] | This is a protein folding program that supposedly helps find cures to cancer, Alzheimers, etc. I was wondering how effective these distributed computing systems are. Thanks! | [
"Define effective. ",
"The site lists over 120 papers that have resulted from access to these donated computing resources. Without doubt this has been invaluable to the groups who use the service. This kind of project is of critical importance to groups who work at smaller institutes and don't have local access t... | [
"Quantum computing allows you to run quantum algorithms. In the main these are a class of algorithms that will run in polynomial time (quickly) on a quantum circuit where they would run in super-polynomial time (exceedingly slowly) on a classical circuit.",
"https://en.wikipedia.org/wiki/Quantum_algorithm",
"If... | [
"Foldd@home has not contributed much in relation to what we need, or it has not contributed much in relation to other methods?"
] |
[
"Is mercury in canned fish a real issue?"
] | [
false
] | I was reading about eating canned tuna in and it reminded me about the fact that there is mercury in canned fish. How much can you safely consume? Somebody mentioned that the more expensive cans are from younger fish who haven't had time to accumulate larger levels of mercury like the older fish of the cheaper cans. | [
"The real danger with mercury is Biomagnification. ",
"Wiki has a nice picture of it listing human monthly intake levels: ",
"http://en.wikipedia.org/wiki/Mercury_in_fish"
] | [
"The FDA provides an excellent ",
"table",
" concerning a broad range of fish and their mercury levels.",
"Worth noting: salmon have much lower levels than those of many other fish."
] | [
"As a panelist/expert I strongly endorse this table, and endorse minding it for seafood choices. As fish is extremely healthy (omega 3s and all that), as a personal choice my family eats seafood twice/week that's low on the list but limits anything high on the table to very occasional (and completely avoided when ... |
[
"How are filters of specific pore sizes manufactured, especially those on the micron scale?"
] | [
false
] | I was thinking specifically of filters that have specific molecular weight ranges, such as 15 kDa or 30 kDa. | [
"The general area is Sol-Gel processing. \"Sol\" stands for solution and \"Gel\" stands for gelation. Essentially, you mix two chemical solutions together and reactions occur such that long chains start to form and the liquid solution turns into a soft solid, like gelatin. You can then dry these gels using differen... | [
"Sol-gel is not based on long chains it is all about particles, it has been proven beyond a doubt even though some text books still try to teach it like you are describing."
] | [
"This might be a good question for ",
"/r/askengineers",
" ",
"A lot of times finding the public information online about things like this is knowing the terms to google like ",
" filter manufacturing.",
"High level page: ",
"http://www.millipore.com/membrane/flx4/filter_manufacture_hm&tab1=3#tab1=3"
] |
[
"What is the role of norepinephrine in comorbid ADHD and anxiety?"
] | [
false
] | I'm going to try my best to provide sources, but a lot of them disagree with each other which is pretty much why I'm asking this question. So apparently ADHD is linked to a deficiency of norepinephrine ( ). Norepinephrine is also linked to the fight or flight response, and increases heart rate, blood pressure and anxie... | [
"In neuro chemistry the goal is to get the brain in a certain balance, too much or too little of a neurotransmitter can cause problems.",
"If you are deficient in norepinephrine your attention will suffer because you aren't stimulated enough, if you have too much you are stimulated to a point that you will be pus... | [
"Yeah, but how can someone have anxiety and also ADHD then? How do you simultaneously have too little and too much of the neurotransmitter?"
] | [
"The ",
", lack of or excess of is what causes the symptoms.\n",
" of norepinephrine will cause concentration and impulsivity issues.",
"Also some neurotransmitters work together, if one is too low or too high then it can effect other neurotransmitters. This is a hard thing to get exactly right.",
"For exam... |
[
"How does a planet get its axis?"
] | [
false
] | [deleted] | [
"If you have a ball, any ball, you can make it rotate around different axes. The axis isn't anything concrete until you make the ball rotate. And once you do, there is a single axis around which it rotates. So the axis of planets is just determined by how they rotate.",
"All planets in the Solar System do orbit t... | [
"Can there be a planet that revolves around a sun and has an axis so that half of it would always be dark constantly?",
"Yes, a planet can be ",
"tidally locked",
" to the star it orbits - although no planets in the solar system are tidally locked, it's thought that some of the extrasolar planets that are in ... | [
"no planets in the solar system are tidally locked",
"Although, many moons are tidally locked wrt their planet."
] |
[
"Why does the search for extraterrestrial always have to be on earth like planets?"
] | [
false
] | I've always wondered why nasa searches for earth like planets when looking for signs of life? Why does life have to be exactly like it is here on earth? | [
"They search for earth-like planets for other reasons, including the ability of humans to live there. It's interesting if we find life on Venus, but we aren't moving there.",
"Also, they are using a standard scientific approach. We know for a fact that life can and has evolved under conditions like those found ... | [
"Why does life have to be exactly like it is here on earth?",
"It doesn't have to. But we have no means of directly detecting the presence of life from afar, so the best we can do is to detect conditions/environments which we know can support some form of life. Since we have only the template for life on Earth ... | [
"I've always had a beef with this, too, because I personally would be more interested in anything that evolves, whether or not it uses carbon (or even chemistry for that matter). For example, there might be self-reproducing, mutating, and surviving patterns in electromagnetic radiation that we are not aware of bec... |
[
"Why hitting the bottom of my coffee cup (and yours probably...) does this ?"
] | [
false
] | Hello ! been wondering since a while now and didn't take time to ask you physics pro. I think video is self-explanatory but here is the thing: As I keep hitting the bottom of the cup the sound is getting higher and higher. It looks like it's linked to the coffee movement. What is the physic phenomenon here please ? I'm... | [
"This is essentially the Hot Chocolate Effect. ",
"When you first start stirring the coffee air bubbles get trapped inside the coffee reducing the speed of sound in the it lowering the frequency. As the bubbles begin to get released from the coffee sound travels faster in the liquid and the frequency increases ag... | [
"This is absolutely correct! I am really happy to see that the correct answer floated up to the top this time. Usually people have some silly conversation about temperature and the speed of sound in water or some nonsense, but ",
" are the right answer.",
"To elaborate on this, sound speed is given by c = √(B/ρ... | [
"Check out ",
"this big thread",
" about a year ago, on this exact topic."
] |
[
"Why can we compare numbers to infinity although we do not consider infinity a number in itself?"
] | [
false
] | null | [
"Do you have a particular context in mind?"
] | [
"It is mostly just convenient notation: \"n < ∞\" just means that ",
" is finite.",
"However, we can extend the real numbers ",
" by adding two elements, -∞ and +∞, to form R-bar, the ",
"extended real numbers",
". The elements +∞ and -∞ are not real numbers, but are defined so that +∞ is greater than all... | [
"any positive number compared to +INF is \"<\" than it ( ex : n < inf ) but why can we compare a number to something which is not a number technically"
] |
[
"Do different people see different ranges of the visible light spectrum?"
] | [
false
] | Different people, of course, can hear different ranges of frequencies of sound waves, as we learn in middle/high school science. I was wondering if the same happens with light? Are there some very low frequencies of red light, or high frequencies of violet light, that some people can see and some others can't? Does thi... | [
"Although (aside from the color blind) all humans have nominally the same three color receptors, there does exist natural variance in the genes encoding these. These variants do not have exactly the same activity profiles. Now, this wouldn't have a significant effect on the visual spectrum, but it could cause sligh... | [
"Do you know how insects deal with UV then, since they are able to see and use it? Or do they just don't live long enough for the UV to have impact?"
] | [
"So, i actually don't know, and I don't know if the answer is known at all. I would hazard a ",
" it's simply that they are evolved for it since they use it, and we are not because we don't.",
"Insect eyes do not have anywhere near the focusing power of vertebrate eyes, so the total intensity falling on any one... |
[
"Baby Talk and Language Acquisition"
] | [
false
] | We are babysitting my brother's niece. He and his wife are adamant about not using baby-talk around her; they insist it will damage her in some way. My parents baby-talked (baby-spoke?) the two of us, and I like to think that we turned out just fine. What is the askscience take on how a baby begins to apprehend langua... | [
"It has also been speculated that baby talk helps emphasize basic phonemes involved in the language spoken. ",
"http://www.ncbi.nlm.nih.gov/pubmed/9235890",
"In the early months of life, infants acquire information about the phonetic properties of their native language simply by listening to adults speak. The a... | [
"My impression from when I studied linguistics is that kids who are exposed to language use will learn to speak despite anyone's best efforts to the contrary. If you want better terms to search on, you could try \"motherese\" or \"child-directed speech\". From what I've seen, it is generally thought to improve la... | [
"Although my field is computational linguistics, I have heard some about this from generic linguistics classes.",
"As far as I've been taught, child-directed speech is actually better for the child. There may be studies on either side but as far as I know it's scientific consensus that it aids the acquisition of ... |
[
"Can someone please explain how the NERF Firevision products work?"
] | [
false
] | I am very intrigued by the product description, but I am also very curious how it works and how well it works. Key phrases that make it interesting/mystifying: What I can surmise is that the light emitted by the frames is caught and brilliantly reflected by the ball. What I can't figure out is the apparent 'special eff... | [
"As far as I can tell, the ball simply has retro-reflectors ('microprism technology') and the glasses have red LEDs. The retro-reflectors on the ball reflect the light back to the source, with a bit of scattering. Similar to road signs, roadwork vests, and the like. ",
"Each tiny retroreflector is shaped like cor... | [
"The light from the glasses is directly reflected towards the wearer of the glasses. This is because the reflectors use a corrugated mirror to reflect the light, using the same principal as ",
"bicycle reflectors",
". The special glasses have lights and in the details it states: ",
"\"Requires 4x 'A76' batter... | [
"looks like a cool toy, but what I don't get is why companies make up totally stupid technobabble for stuff like this . . . Microprism Technology lol",
"I wonder if there's a way to adapt the retroreflection and head mounted light source to work with infrared or polarized light . . . It might be cool to have a gl... |
[
"There are over 200 types of Cancer that negatively affect humans, is it possible for the disease to manifest in a way that would be positive?"
] | [
false
] | At it's core Cancer as I understand it is a mutation affecting cell growth. There are over 200 different types of Cancer that all negatively affect humans. Would it be possible for the disease to mutate or change in a way that would make it helpful rather than harmful? And if that happened, would it be a step forward ... | [
"Another note to add: we are finding that different locations within the SAME tumor can possess different markings and genetics. Essentially, there is no such thing as a single \"type\" of cancer, each is kind of its ecosystem of genetic mutations."
] | [
"No, probably not. Cancer isn't exactly a conventional \"disease\". What happens is, mutations occur over time in individual cells. Most of them are fixed either directly, or via apoptosis of the cell (the cell \"commits suicide\" and materials are recycled). If a single cell escapes termination or repair and enoug... | [
"Cancer is uncontrolled cell growth. Not all the time does the cancer become malignant and spread everywhere. I remember an autopsy studying stating that a majority of men over the age of seventy die ",
" but not from prostate cancer. They never knew they even had it. So you can have a tumor that sits there and e... |
[
"What happens when lightning strikes in the ocean?"
] | [
false
] | Typically, when electric current goes through a small body of water, like a bathtub, the water carries current and results in someone sitting in the tub being shocked. However, obviously when lightning strikes the ocean, the whole world doesn't get electrocuted. So... How far does the ocean (or any large body of water)... | [
"Wait, hang on - does that make any sense at all? You can't say \"a lightning bolt consists of 100 kV\"... Voltage is the potential difference ",
" points. I would figure that wikipedia is saying that the voltage ",
" by 100 kV between the lightning source and the ground.",
"That wikipedia article even tells ... | [
"According to Wikipedia, an average lightning bolt consists of 30KA and 100KV, thus when it strikes the water it will need to go through 3.33 Ohms of resistance before dissipating. A meter of salt water at 20 Degrees C has 0.20 ohms, so assuming a straight path down, worst case scenario (think a string of resistors... | [
"I remember doing ",
"these calculations in class",
". I'm not sure if I can properly explain it here, but I'll try. I'm going to throw some concepts at you, keep them in mind, then I'll put them together at the end. ",
"When you want to know if you're going to get shocked or not it depends on voltage potenti... |
[
"Why aren’t/can’t non-recyclable plastics be processed and used as aggregate in construction applications?"
] | [
false
] | null | [
"That depends on the types of plastics in question.",
"For some plastics I'm sure this would work fine. There are others however, that aren't going to meet compaction standards for fill, and further others that may leach chemicals into the ground as they slowly decompose."
] | [
"research on alternative aggregates is ongoing, at least one grad student in my program is working on a parallel idea. a few things that come to mind would be thermal expansion factors as well as interactions with the concrete mix and additives. strength and uniformity/dependability of the aggregate is important, c... | [
"Couldn’t this be a viable solution to at least part of the problem of non recyclable plastics? I understand not all of them would be suitable, but..."
] |
[
"Are planets and stars limited to how big they can get?"
] | [
false
] | [deleted] | [
"Well, if a \"planet\" gets too big it starts undergoing fusion and is a star."
] | [
"Yes, there are limits on the mass that a star can naturally attain. There is a number called the \"Eddington limit\" that discribes the maximum size that a star can obtain (150 solar masses for MOST stars, with rare exceptions for suspected Population III metal-free stars like R136a1).",
"The Eddington limit ba... | [
"Sure. The size of stars is limited by the Eddington luminosity (with luminosity being related to size). If they get too big and bright, radiation pressure starts blowing them apart more and more.",
"If planets becoming too big, they start undergoing fusion and stop being a planet."
] |
[
"Whats the difference between Osmosis and Capillary Action?"
] | [
false
] | I thought water moves from higher concentration of water to low concentration of water ( I maybe wrong about this) and that is why water will pass through a permeable membrane of different concentration. Isn't capillary action similar to this in the sense that the water is moving to an area where there is lower concent... | [
"Capillary action is to do with surface tension, where for instance water is attracted more so to a glass tube and will have a curved surface and rise up a tube, ",
"look here for diagrams",
"\nCapillary action is not a change in concentration.",
"You are pretty much on the right track with osmosis from what... | [
"No, water moves to the area of higher solute concentration. OP was right but phrased it in an odd way."
] | [
"Osmosis is where water moves from an area of lower solute concentration to one of higher concentration. So OP just phrased it differently.",
"EDIT: Thanks to chemistree for finding my herpderp error."
] |
[
"How does Shazam work?"
] | [
false
] | null | [
"I actually worked with Shazam for a while when my employer at the time was partnering with them. They generate a \"fingerprint\" of the audio and then I assume they segment that in a way that you can then search on parts of songs.",
"It's probably similar to this project ",
"https://github.com/worldveil/dejavu... | [
"Sorry for the mobile link.",
"Shazam and others like it use a variation on Fourier Transforms to generate a fingerprint that is extremely compact and easy for a computer to analyze. ",
"This is also part of the secret that allowed mp3 files to be so compressed and yet play back at high quality.",
"https://e... | [
"I have read a bit about the general procedure of fingerprinting songs, and a few friends of mine worked on developing their own version of the software. DejaVu, the software linked in another comment, has an excellent description of the process, complete with visuals. For those who don’t want to look it up, I can ... |
[
"Are there chemicals that, once ingested, will never leave the body?"
] | [
false
] | I've heard that ingesting certain chemicals (either by breathing them, absorbing through the skin, or consuming with food) have a cumulative effect on the body because they don't leave with the rest of the bodily waste (This is evidently what people who claim "detoxing" works are supposed to be curing.) How true is thi... | [
"\"Never\" might be a bit of a strong word for something that's ultimately statistical. But yes, some things can stay in your body effectively forever, the technical term for this is ",
"bioaccumulation",
". These tend to be compounds (such as heavy metals) which end up in your fat tissue, (and will remain ther... | [
"So by losing weight, and thereby reducing my body fat, I'm washing the heavy metals previously stored in my fat tissue... where? Back into my blood?"
] | [
"Back into the blood. I'm not sure of the extent to which that happens with heavy metals (as they can end up in other places as well), but ",
"that does happen",
" for fat-stored, bioaccumulated toxins like PCBs and DDT."
] |
[
"In hunting, poison-tipped arrows are used. Is the animal's flesh treated in some way to render the poison harmless?"
] | [
false
] | null | [
"Curare is what South Americans use. It's ",
"not effective if taken orally",
", so it's safe to eat your kill.",
"Curares are used medically when muscles need to be relaxed or paralyzed for certain procedures. In ophthalmology, it's used to paralyze the eye muscles while replacing a cataractic lens, for exam... | [
"Some are effective only when introduced to the blood stream (e.g. ",
"Curare",
" and ",
"chrysomelid beetles",
"."
] | [
"I once met an indigenous tribe in Borneo, they still used poison blow darts to hunt with, they told me a small amount about what they used. Apparently as long as it didn't get into your blood stream it wouldn't kill you. \nHowever before eating a kill they would cook it and cut out and discard its heart.\nNow how ... |
[
"I see a lot of people arguing over the validity of \"The China Study.\" Can someone provide me with an unbiased critique?"
] | [
false
] | The China Study was a study conducted throughout the 1970's and 1980's in which researchers monitored the health and lifestyles of the rural population in China. Many people tout it as evidence for a vegetarian lifestyle, others say the study is garbage. The issue is, I can't find any comments on it from unbiased sou... | [
"Disclaimer: this is not my field, but I have followed the literature on this topic in some depth. The China Study is an observational epidemiological study. You can't infer causation from those studies, but you can rule out and rule in some hypotheses. It is consistent with quite a bit of other data suggesting tha... | [
"Here is a blog post by Robb Wolf, ",
"\"The China Study: Junk Science and Lies\"",
" that links to some articles \"refuting\" the work of the China Study, in particular this link to a ",
"rebuttal by Loren Cordain",
", which is extra interesting as it contains comments by Campbell, which are not very convi... | [
"http://rawfoodsos.com/2010/07/07/the-china-study-fact-or-fallac/"
] |
[
"What kind of information can I get on my own with my \"uninterpreted raw genetic data\"?"
] | [
false
] | For example, like the data I can get from 23andMe. I'm interested in using open source software to help interpret the data. | [
"Google prometheus. They can interpret the raw data for $5 and their website should give you a description of what they offer. "
] | [
"You get the complete raw data, so you can get the same info you could prior, just with a different service. A friend of mine just did it a week ago."
] | [
"The site is ",
"https://promethease.com/",
".",
"My understanding is that 23andme used to provide quite a bit of health risk information, but were shut down by the US FDA who deemed the service an unapproved medical device. It looks like this site can import their data and match it up with the SNPedia -- an... |
[
"Have the measurements of time always been standard?"
] | [
false
] | [deleted] | [
"This might be worth cross-posting to ",
"/r/AskHistorians",
". From my (very limited) understanding, there were many, many ways of dividing time before the invention of clocks, each with different units.",
"Since mechanical clocks were invented in a particular time and cultural context (16th century Western ... | [
"I vaguely remember from a documentary that a Chinese astronomer divided the day up into something like 100 units (14.4 minutes) in order to track star movements. It could have been Yi Xing or Su Song. See 3rd pargraph ",
"http://en.wikipedia.org/wiki/Unit_of_time"
] | [
"Much like how the concept of unit measuring in metric is more efficient than the imperial measurements",
"I'm not sure that's strictly true... I think a prime example of why metric isn't always the best choice for units is, in fact, ",
"decimal time",
". While a good idea in theory, in practice, it's untenab... |
[
"In domestic violence, why do victims stay with their abusers?"
] | [
false
] | [deleted] | [
"In short, it is because the circumstances under which abuse take place make it very difficult for the victim to leave. ",
"The abuser almost always makes certain that the victim is ",
" before actually engaging in abusive behavior. This can take several forms:",
"Financial dependence: The abuser is the only ... | [
"Alright, let me see if I can answer those adequately.",
"The concept of protecting minors and the elderly from abuse is a legal one, and stems from the fact that children and elderly adults do not have the same capacity to protect themselves as healthy adults. In minors, this is because of a lack of experience/n... | [
"Alright, let me see if I can answer those adequately.",
"The concept of protecting minors and the elderly from abuse is a legal one, and stems from the fact that children and elderly adults do not have the same capacity to protect themselves as healthy adults. In minors, this is because of a lack of experience/n... |
[
"If both parents weren't overweight and obesity doesn't run in your family.. What are the chances an offspring will be obese ?"
] | [
false
] | [deleted] | [
"It depends on the child's diet. Although he will have no predisposition to obesity, he can still become obese."
] | [
"Why higher than average if both parents are not overweight if the child is influenced by them? "
] | [
"Sorry, read that wrong. I thought it read \"were overweight, but it didn't run in the family\""
] |
[
"I hope this isn't a dumb question but, how do calculators work?"
] | [
false
] | It seems pretty intuitive that when adding 1 and 1, the calculator would maybe put one dot next to another dot and then count the sum. Or something like that. But once you get to higher level operations, such as larger scale multiplication, powers, or trigonometric operations of decimals, my idea is obviously wrong. Th... | [
"Imagine an incredibly simple electronic calculator: one that can only add together 2 2-bit binary numbers and produce a 3-bit binary output.",
"The first number is represented by nothing more than 2 toggle switches, which can be either up or down (on or off, 1 or 0). Thus you can represent 0: 00, 1: 01, 2: 10, a... | [
"http://www.lifeslittlemysteries.com/1408-how-calculators-calculate.html",
"You can always google straightforward questions. Feel free to ask questions about specifics and understanding. If you've never seen anything about circuits or binary before this might get a little confusing."
] | [
"that's about right. electronics only have the capacity to perform elementary operations (addition, subtraction, multiplication, division, and division with dividends). fortunately, all the other functions out there, like sine or natural log, can be approximated using such methods as taylor series. when a calculato... |
[
"If you have two peas in a vacuum and one is moving 100 mph away from the other pea (assume they start touching eachother), given an infinite amount of time will they come back together?"
] | [
false
] | null | [
"They will never come together. Their relative velocity is much greater than their mutual escape velocity, even if they start out touching each other. Even though gravity has infinite range, and will always be accelerating each one towards the other, they have more than enough kinetic energy to escape."
] | [
"So would it be similar to subtracting 1 from 10, then .1, then .01... ect going on forever. You are getting a smaller number each subtraction but you will never hit zero."
] | [
"Yes, it's like that."
] |
[
"Why do quantum physicists operate their testing equipment on earth?"
] | [
false
] | [deleted] | [
"You're acting like it's no big deal just to pop into space and get'er done."
] | [
"They are planning to do it in space",
", it's just that everything is much more expensive and complicated in space. It takes much more planning, research, and time invested to send an instrument into space, which is why the usual pattern is that we perform the experiment here on Earth first as best we can befor... | [
"Ah, thanks! It was something I thought up earlier today, and was kind of plaguing my mind. I'm glad there is a project in works to try it."
] |
[
"What exactly is \"Information\"?"
] | [
false
] | In many other posts they say that information can not travel faster than the speed of light, but what exactly is information and what can be considered not information. | [
"At its most fundamental, information is any propagation of cause and effect within a system. The degree to which the the past state of one part of the system can be known through observation at another part of the system. Effect can only propagate at the speed of light (since nothing can go faster).",
"Informati... | [
"I thought of calling it 'information', but the word was overly used, so I decided to call it 'uncertainty'. [...] Von Neumann told me, 'You should call it entropy, for two reasons. In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the ... | [
"Information theory was basically created by turing, Shannon and Von Neumann (most prominently) in the 40s-50s. Since then it's been pretty widely accepted. So depends on your definition of new."
] |
[
"Does smoking (vaporizing) alcohol affect the liver and body the same as drinking it?"
] | [
false
] | null | [
"Yes, alcohol arrives at your liver via the blood. Whether it gets to the blood through the intestines or through the lungs wouldn't make any difference, except to your stomach and intestines. Most metabolism of ethanol doesn't begin until it reaches the liver."
] | [
"Not entirely accurate. When drugs are delivered directly to the blood stream they may or may not reach the liver. If they are ingested to the intestines they reach the liver through the \"portal\" circulation and make it to the liver where they are metabolized. This is called the \"first pass\" metabolism. Drugs t... | [
"People would get drunker faster",
"True, I was thinking more about the effect on the liver. Eventually wouldn't the alcohol would reach there and be metabolized just the same as if it had gone through the intestines?"
] |
[
"I am allergic to some dogs. Can a dog be allergic to me?"
] | [
false
] | Can animals be allergic to humans? | [
"So here's the setup:",
"All an allergy is is an \"inappropriate\" immune response of a given kind. (\"Appropriate\" is relative. That's whatever we want to happen. Killing bacteria and stuff, mostly.) Most seasonal/animal/dust allergies are the result of Th2 T cells triggering your B cells to produce IgE, a cert... | [
"Yes. Veterinary Technician here. We routinely send allergy panels on dogs and cats to the lab, and one of the allergens on the list is human dander. I have seen one case of a cat that was allergic to her human! This is treated with twice daily injections produced at the lab."
] | [
"Oh, okay - well, absolutely. Most immune responses are/can be mounted against single molecules. An antibody/B cell receptor recognizes a bacterial cell by binding to one region of one molecule (called an \"epitope\") - you could definitely get them to do the same thing in the absence of all the other crap attached... |
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