title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Does drinking alcohol help \"flush\" THC from the body?"
] | [
false
] | null | [
"Drinking lots of liquid will not help eliminate THC. You're only diluting the urine, but other indicators in the urine will show that it's highly dilute.",
"Also, most of THC metabolites are eliminated in solid waste"
] | [
"THC is fat soluble and stored in body fat. Alcohol never gets to it. "
] | [
"Alcohol inhibits ADH which will make your body flush liquids. Unless you plan on showing up wasted, the next day your urine will be more concentrated and probably show a higher concentration of THC in your system. The opposite, however, is water loading. The first thing a toxicology lab does is check specific grav... |
[
"Can we possibly quantify all of the energy in the universe?"
] | [
false
] | I was watching a National Geographic documentary called "The Known Universe" and it outlines a lot of colossal cosmic entities that spew out/contain massive amounts of energy. Things like pulsars, gamma ray bursts, magnetars, neutron stars, etc. So, with all of those things in existence, would the amount of energy in the universe be even conceivabe in our scales? Would we even have a number to represent something that large? Sorry, I'm not asking a series of questions above, but just trying to clarify my original question (in the title). Thanks in advance. | [
"This might not answer the question in exactly the way you wanted, but . . .",
"The total energy in our universe is equal to zero. This hypothesis is central to the theory of the Big Bang. ",
"Basically, all matter, light, etc., is considered a positive form of energy. But for every bit of positive energy th... | [
"The total energy in our universe is equal to zero. This is central to the theory of the Big Bang. ",
"Sorry, no, it's not central to the theory of big bang. It's just ",
"an hypothesis"
] | [
"You are correct sir. In my attempt to answer quickly while multi-tasking I wrote the word theory when I meant to write hypothesis. I shall correct it momentarily. "
] |
[
"Can fully intact cells survive the digestive process?"
] | [
false
] | I know spores of some bacteria can survive the acidic environment of the belly. But can fully grown prokaryotic cells survive digestion? Eukaryotic? | [
"See giardiasis and amoebiasis. Also see Taenia solium and Taenia saginata."
] | [
"Thank you, I was having a brain block. I couldn't think of parasites for some reason. "
] | [
"http://www.nytimes.com/2011/12/27/science/how-can-plant-seeds-survive-the-digestive-process.html"
] |
[
"If you were standing on the Moon and the night side of the Earth was in view, would you be able to see any urban light?"
] | [
false
] | We've all seen images showing Earth's artificial light at night. These images are obviously mosaics and enhanced to show the night lights. However images taken with normal cameras from the ISS also show very . So the question is could you also see these from the Moon? I think you might be able to see large urban areas such as Western Europe from the Moon. Especially considering that the Earth's diameter is about 4 times larger than that of the Moon, so it looks much bigger from the Moon than the Moon does from the Earth. ... Edits: *After some more searching I'm still not sure, I've found. I've taken from the Moon during Apollo missions. None of them show urban light, but that doesn't say much because you also don't see any stars on them, meaning they were taken with a lower light sensitivity than our eyes. Also there was much less artificial light during the Apollo missions than there is today. There is in the list that does show a crescent Earth with night lights taken during an Earth flyby. I can't find the sensitivity of the instrument, however some urban centers look brighter than the background stars, so they would probably be visible to the naked eye at this distance. However this photo was taken at a distance of 80,000 km, so that only gives a lower bound not even close to 384,400 km Earth-Moon distance. **Found from the Japanese Kaguya lunar orbiter showing Earth during a lunar eclipse. Also taken while the craft was still in the lunar night. You don't see any city lights, but you also don't see any stars, so again it's impossible to draw a conclusion. ***In , also from Kaguya you do see at least one patch of light (or maybe some more if you ). But it could be an artifact, noise, or lightning. You also see stars in the photo so at least the sensitivity is close to our own, but still quite a bit lower because the stars aren't very bright and there is a lot of noise. Still no definite conclusion but now I think it's very close to the edge of either being very faintly visible or not visible at all. I don't think there are any clearer pictures, so unless someone can do a convincing calculation based on a quite difficult estimation of the maximum brightness of urban lights, we won't know until another probe is sent or we go there ourselves. Luckily, the might land a rover capable of this before the end of this year! | [
"Whenever it is night on Earth and the Moon is not full it means you can see Earth at night from a place on the Moon where it is also night. A half Earth could indeed be too bright, however a new Earth would be mostly black.",
"*Found this ",
"fancy Earth viewer",
" which shows the phase of the Earth as would... | [
"Sure, but your eyes would adjust for the landscape, which is basically a light grey in full sunlight, i.e. very bright.",
"You could always control it by bliocking the sun, closing your eyes, whatever, but i suspect you wouldnt see cities at that distance if you were not adjusted for night vision.",
"Let me pu... | [
"How the heck would it be both night on the moon and night on earth on the sides facing each other?"
] |
[
"Dear immunologists of Reddit, regarding the flu vaccine..."
] | [
false
] | Is there any particular reason why the flu vaccine cannot cover all known strains of the disease? I know that in previous years coverage for multiple strains have been all contained in one shot. In the 2000 flu season strain matching was so poor that there was zero measurable effect of the vaccine against the flu. I ask as I am one of those folks who don't like getting a flu vaccine and this is one of the main reasons why not. Please, no insults, just address the question. | [
"The reason that we need a yearly flu vaccine is that the flu virus has an extremely high rate of mutation. You can think of there being many, many different and new strains of the flu out there in the wild. This being the case, it's simply not possible to cover all known strains of the flu because there are so man... | [
"About your first set of questions: Any given vaccine may weakly cover closely related strains of the flu, but you can't target a given mutation group because these mutations are random: There is no \"group\" of mutations that occur. Antibodies are highly specific, and a large part of how your immune system creates... | [
"I'm not an immunologist but from what I understand is the vaccine you're offered each year is what the CDC predicts will be the most likely varieties. There are lots of different strains that come and go, so I'm guessing this is just the most practical. ",
"The influenza shot you receive is about 1 ml of fluid... |
[
"How can we be carsick when we are awake but when we are sleeping we are not carsick when we wake up?"
] | [
false
] | This happens to me all the time and I am wondering out of pure curiosity. | [
"You won’t be car sick when you’re driving, as your brain is actively looking at where you’re going all the time "
] | [
"My understanding of car sickness is your brains struggle for control. When I sit in the back seat I get car sick, when I drive the same road, at the same speed, I’m good. Your brain can predict what it can control (steering). When your brain can’t control the motion= vomit. When you are asleep your brain is on ... | [
"I've gotten motion sickness when I switched from walking to riding a bike. I've always found it more of a visual thing that causes it. I'm fine on boats, it's the change in speed that I'm used to that does it until I adjust."
] |
[
"atmosphere/weather question"
] | [
false
] | [deleted] | [
"When you say \"weather patterns\" what do you mean? The determining factor as to whether or not the rotation of the earth (coriolis force) impacts a given weather event is the scale of that weather event and its mean velocity relative to the surface of the earth. A fast moving small scale storm will be deflec... | [
"Good explanation, but I think you're underplaying it a bit. Jet streams, which are caused largely thanks to the coriolis effect, have a huge influence on storm tracks. And storm tracks would be one of the most important factors for anyone trying to determine the weather patterns for most areas."
] | [
"Hairy ball problem is relevant. ",
"On an ideal sphere (which the Earth is not) with a flat surface (the atmosphere is not) there must be at least one high/low pressure system pair. Hence, weather."
] |
[
"Why handgun bullets are rounded?"
] | [
false
] | I've seen plenty of handgun bullets but I actually have one of them being pointy as a rifle bullet. It seems counterintuitive to me why two things sharing same purposes have to be so different in their shape. Example images: * * | [
"The arguments about velocity have some merit. ",
"However, there are plenty of heavy rifle bullets that have a blunt, rounded profile. If, for example, you are using a rifle to shoot a rhinoceros at 50 yards, you don't care how much the bullet slows down or drops at 300 yards. You want a lot of penetration. Larg... | [
"\"Better\" isn't just about penetration.",
"Let's start at the beginning. The kinetic energy of the bullet is its capacity to damage tissue. For a given cartridge, the light/fast loads and the heavy/slow loads will usually have pretty similar kinetic energy (at least at close range, where velocity is still appro... | [
"My educated guess is that rifle rounds are meant to travel distances over 100 yards. Not that they can't be used in closer situations, they can, but if you do need to make a longer shot you need to have an aerodynamic bullet.",
"Handgun rounds are not meant to be used for distances past 50 yards (this is an appr... |
[
"Do I sweat when I'm in a really hot shower and just not realize it because I'm already drenched?"
] | [
false
] | null | [
"It takes a lot more energy to change the state of water (evaporate liquid or melt ice) than it does to just raise the temperature in one state. I don't know the numbers, but I think sitting in a swimming pool may not cool you as well as evaporating sweat, besides which your body probably doesn't know to shut off y... | [
"It takes a lot more energy to change the state of water (evaporate liquid or melt ice) than it does to just raise the temperature in one state. I don't know the numbers, but I think sitting in a swimming pool may not cool you as well as evaporating sweat, besides which your body probably doesn't know to shut off y... | [
"It takes a lot more energy to change the state of water (evaporate liquid or melt ice) than it does to just raise the temperature in one state. I don't know the numbers, but I think sitting in a swimming pool may not cool you as well as evaporating sweat, besides which your body probably doesn't know to shut off y... |
[
"Standing on a rock at the absolute edge of the Milky Way, facing away from the galaxy. What do I see above me?"
] | [
false
] | Is the sky filled with stars? Do I only see light from the local cluster, or is it mostly pitch black? Also, if you have any material on this I’d love a link. | [
"It would be mostly pitch black.",
"There is no absolute edge of the Milky Way - there's just fewer and fewer stars as you go further out. So once you're far enough out that there's no stars close enough to be visible as individual stars \"in front\" of you, you're in a region that's so lacking in stars that ther... | [
"We're about half way out, depending on how you count it - like 30,000 light years from the centre. You do see the Milky Way as a full 180° band around the sky (you don't see it all at once because the ground is in the way, but you do get to see much of it throughout a year, or even through a night as the Earth rot... | [
"The ",
" you get does increase as you get closer, but the ",
" doesn't change. So yeah, Andromeda won't really get brighter in terms of surface brightness (maybe a little bit because there'll be less dust in the way) but we will be getting more total light from it, because it'll take up more of the sky."
] |
[
"What is the most efficient method of storing massive amounts of electricity as kinetic energy?"
] | [
false
] | By massive I mean the amount a typical US home would use in a day or week. | [
"The average american home used 10837 kilowatt hours in 2012. ",
"source",
" The country generated 4.1 trillion kilowatt hours in 2012. ",
"source",
" An average home doesn't comsume that much power in the scheme of things. I am curious, so let's find out what kind of kinetic storage we can do. ",
"10,837... | [
"What kind of vehicle needs the kind of power that can't be stored in batteries is also small enough not to have an onboard power plant? I'm both curious and afraid. "
] | [
"What about flywheels? Can these replace a simple falling weight?"
] |
[
"Why do we have such bad quality pictures of pluto, but such great quality pictures of objects like the Sombrero Galaxy?"
] | [
false
] | null | [
"Even though it's so far away, due to its size - not to mention all those luminous stars it's got burning, compared to Pluto's dim reflections of the Sun - the Sombrero Galaxy looks much larger and brighter than Pluto does.",
"In terms of brightness, Pluto's apparent magnitude has a mean of 15.1, while the Sombre... | [
"The best example I can think of is their angular size in the sky.",
"Galaxies are very far away, yes, but they're also REALLY FRICKEN MASSIVE. I think andromeda's size is actually eight times that of the moon in the sky, it's just so faded that you can't see it. When you have a space-set camera like Hubble, all ... | [
"Andromeda's angular size is 6x that of the moon, according to Wikipedia. ",
"This is amazing to me. I would not have guessed it."
] |
[
"Why does the sun look larger as it sets?"
] | [
false
] | null | [
"Because you have some refrence with the forground. The moon or sun looks massive when its on the horizon because you can compare its scale to the objects on the horizon, but in the sky their is nothing, so it looks small in the ocean of blue, here is a picture i took for refrence ",
"https://i.redd.it/q2gk7kewry... | [
"the sun would look larger though as it has more atmosphere to refract off of.",
"No, this explanation is a common myth, and is incorrect - check out ",
"the Moon illusion",
".",
"The effect of atmospheric refraction alone actually makes the angular size of the Sun (or Moon) appear ",
" in the vertical di... | [
"Actually it's a lot more complex than one would think, and the reason is not entirely known. ",
"https://en.wikipedia.org/wiki/Moon_illusion"
] |
[
"What determines the power of a radio transmitter? What is it in big commercial transmitters that makes them radiate more power than tiny DIY transmitters? Is it the antenna size? The operating voltage? What would you need to change in a transmitter circuit to make it radiate more power?"
] | [
false
] | null | [
"In most cases it's in amplifier design. The modulation circuit creates the signal at a low power and this is then fed to an amplifier which increases the current and/or voltage to drive the antenna.",
"To make a more powerful amplifier then requires components that can handle the increased power and still give a... | [
"With vacuum tube power amplifiers, they do use high voltage. The 30 kW TV transmitter I used to work on had a 10,000 Volt, 7 Amp DC supply for the tetrode plate voltage. It also had a big 140 Amp filament supply. That is needed to make the cathode emit enough electrons. We replaced it with an all solid state trans... | [
"Radio amateur here but multiple things.",
"Power amplification.",
"Also antenna size dose play apart a more resonant antenna for the frequency will definitely help. (Lower the frequency longer the antenna (most of the time)).",
"Also directionality will help. If you use a directional antenna you can aim all ... |
[
"What can I do to avoid depression when sleep deprivation sets in."
] | [
false
] | null | [
"This is definitely constitute asking for medical advice, which is prohibited by Reddit's general ToS (see the sidebar ---->).",
"This question has been removed."
] | [
"If the condition is bothering you or affecting your daily function, I would suggest you talk to a health care professional, either a doctor or a counsellor."
] | [
"If the condition is bothering you or affecting your daily function, I would suggest you talk to a health care professional, either a doctor or a counsellor."
] |
[
"How come standing up quickly sometimes gives me a headache, and other times I feel nothing?"
] | [
false
] | I can being lying down for a few hours, get up, and feel fine. Then, I'll be lying down for 20 minutes, get up, and nearly black out (exaggeration, obviously, but still). Any explanation? | [
"Sounds like ",
"orthostatic hypotension",
". When you are laying down, your heart doesn't have to work very hard to pump blood to your head. Since they aren't in demand, your heart and your arteries relax a little. When you stand up, it takes more pressure to pump blood up to your head. To compensate, your hea... | [
"For the case in which it does not happen every time, the most likely cause is dehydration. I bet you do not feel woosy when you have had enough water to drink that day.",
"When you have fewer fluids in your body, your heart has to work even harder to get enough blood up to your brain."
] | [
"Or if your blood pressure is up for some other reason: fear, excitement, stress, etc. "
] |
[
"What would the practical applications of a frictionless object be?"
] | [
false
] | null | [
"... excluding the scientific merit of creating such an object, of course.",
"But how would we answer your question ",
", if you're asking us to ignore it?",
"Friction, at the end of the day, is the result of electromagnetic interactions. Are you asking us to consider a world without this interaction?"
] | [
"Sorry, the question was poorly worded. What I meant in that sentence was, apart from the scientific achievement that creating a frictionless object or materiel would be, what could you use the object or materiel for, either in a day to day sense, or in terms of scientific experiments? A further question would be, ... | [
"Ah, sorry, I'm bad at this. This is presuming that the material in question has perfect smoothness due to its atomic structure."
] |
[
"Why does milk taste fine for several weeks but then spoil all at once?"
] | [
false
] | null | [
"It doesn't actually spoil all at once. It's a continuous process as bacteria, like lactobacillus, consume the milk (primarily lactose sugars) and excrete compounds that aren't tasty, like acetic acid, and replicate so there are more. ",
"That said, it will hit a threshold where your sensory inputs (smell, taste)... | [
"Is this why lactose free milk (with the lactaid enzyme) has a much longer expiration date?"
] | [
"I can't say for sure. I don't really know a lot about lactose free milk. ",
"But if they are simply adding lactase to break down the lactose, than the resulting milk would simply have galactose+glucose instead of lactose. So it would taste sweeter, but there would be nothing different from what the bacteria are ... |
[
"How is it possible for a lab to produce 10 Terawatts, if the world consumes only 15 Terawatts? Is there something I'm overlooking?"
] | [
false
] | [deleted] | [
"It's the difference between power and energy. Well, they sustain that power only for a femtosecond =10",
" seconds times 10",
" 10",
" times 365 days times 24 hours times 3600 sec per hours =4.7 *10",
" Joule. That huge amount of energy. ",
"Oh yes, the people of Intellectual Ventures are assholes.",
... | [
"No.",
"Power is the amount of energy, divided by the time it's being used. So, if the energy is not that big, but it's crammed into a really REALLY ",
" short time, then power would be humongous.",
"That's what happened with the experiment you described. They jammed a moderate amount of energy into an extrao... | [
"10 Terawatts over 3 femtoseconds is only ",
"30 milli-Joules",
". If you have energy output over an extremely short period of time, you can claim a large instantaneous power output."
] |
[
"How well do we understand enzyme kinetics? Can we make predictions on quaternary structure and activity based on the primary structure?"
] | [
false
] | I remember there was lots of cool stuff going on with folding at home for a while now, are we at the stage where we can create a unique amino acid sequence to produce an enzyme with desired properties? | [
"I've done some research both in vitro and in silico with protein folding. ",
"Sort of an overview:\nWe can make pretty good predictions of secondary structure; we've gotten quite good at recognizing certain sequences as alpha or beta helixes, turns, beta sheets etc. ",
"We are pretty good at recognizing small ... | [
"We have a \"model\" to do pretty much everything needed in biochemistry, namely Quantum Dynamics. However, if you don't have higher level \"models\" that work as shortcuts, and provide accurate approximations of behavior, this model is useless, since Quantum Dynamics is EXTREMELY limited by computational power (th... | [
"Very loosely. We can, for example, compare sequences with known crystal structures and infer that proteins with said sequences or similar sequences also have that or similar to that crystal structure. But that's about it. AFAIK, we cannot look at a string of amino acids and by that alone adequately estimate the cr... |
[
"There have been suggestions that there might be a resurgence of Covid-19 in the winter, how likely is this?"
] | [
false
] | And if it is likely, then are countries in the Southern hemisphere already experiencing this? | [
"To be a resurgence there would need to be a sustained decrease in the first place. So far it’s just a surge\nSouthern Hemisphere wise not sure about Southern Africa and South America but Australasia is doing ok. New Zealand just locked down and only have cases at the border currently. We are just going about prett... | [
"To be a resurgence there would need to be a sustained decrease in the first place.",
"Plenty of places had/have that. Globally you don't see that trend as the US and Brazil are in a race to be #1 in new cases."
] | [
"To be a resurgence there would need to be a sustained decrease in the first place.",
"Right, there are about 200,000 new confirmed cases every day worldwide, which likely equates to 2 million total new infections each day, as most infections are never confirmed."
] |
[
"Is there a magnet capable of pulling the iron out of your body? If not, how strong would a magnet need to be?"
] | [
false
] | Question brought on by a movie (not X-men). | [
"From ",
"here",
" ",
"[T]he way the iron is bound up in the hemoglobin, magnetic fields have very little effect on it. It is weakly paramagnetic, like oxygen, aluminum and water, for example. It is therefore slightly affected by strong magnetic fields, but not to the extent that ferromagnetic materials, like... | [
"here's from wikipedia entry for \"Magnetar\"",
"Magnetic field\nMagnetars are primarily characterized by their extremely powerful magnetic field, which can often reach the order of ten gigateslas. These magnetic fields are hundreds of millions of times stronger than any man-made magnet,[5] and quadrillions of ti... | [
"The iron in your blood stream is not the same iron you would find a manhole to be made of. There aren't chunks of metal floating around in your skin. Haemoglobin is the iron containing protein comprised of several molecules responsible for the transport of oxygen. ",
"Here",
" is an example of an iron-containi... |
[
"How can an igloo be warmer than freezing inside without melting from the inside out?"
] | [
false
] | null | [
"This is one of the few concepts i remember from chem/physics, but i still needed wikipedia to help with the details. ",
"Basically, it takes a lot more energy to change state than to change the temperature of a substance. this is called the latent heat of fusion, or ",
"Enthaply of Fussion",
"for example (... | [
"This is similar to using a plastic cup filled with water over an open flame to heat the water.",
"The plastic is kept cool enough not to melt by the water.",
"In OP's case, as you pointed out, the large amount of ice behind the boundary layer keeps cooling it much faster than the warm air can heat it up."
] | [
"Yeah, a common survival tactic is to find a discarded plastic water bottle and use it to boil water for sanitation reasons. Granted you are likely getting some nasty chemicals from the bottle, but, it will kill you less quickly than Diarrhea from water borne sickness. "
] |
[
"In the sense that the blood in your brain will naturally favor the pull of gravity, what are the potential effects of falling asleep on your side? Is there anything out there showing a difference in how the left or right hemispheres may respond to this?"
] | [
false
] | Edit: To clarify what I was asking: I am asking what could be the differences when blood is pooling on the left, as opposed to the right; top as opposed to the bottom. Edit 2: There seems to be a resounding notion that "Circle of Willis" will keep the pressure moderately equal within your brain over a negligible amount of time. However, the pressure differences that may accumulate from side-to-side are not near as powerful as those going from laying-to-standing. So let me add another question: Consider you are a vampire sleeping upside down; is some sort of bodily system going to make it so you acclimate to the difference in blood falling through your body down to your head? I know that when I do inversion in yoga, I get light headed quickly, but is this just because not enough time has passed for me to feel 'normal' once the inversion has started? | [
"Circle of Willis prevents this from happening.",
"Edit: it is both the structure (split hemisphere blood flow), pressure, and flow that prevents this. As an aphasiologist, if I could make blood flow one way, I definitely would! Sorry for the brevity."
] | [
"The brain has pretty efficient auto-regulatory mechanisms to control blood flow. Basically the blood vessels will alter their diameter in response to a variety of stimuli in order to get blood and oxygen to where it's needed. So say you lay down on your left, the blood pressure on the left would be slightly higher... | [
"For the lazy.",
" It's basically a system of arteries, with some redundancies, that supplies the brain with blood. Those redundancies make sure that blood circulates throughout the brain even if there's a blockage, or in this case, too much gravity.",
"I'm not at all an expert, but I still feel like laying on ... |
[
"What's the reason I don't remember every moment in my life? Is it because my brain is not recording every moment or my brain cannot retrieve what it has recorded?"
] | [
false
] | [deleted] | [
"Remembering every part of your life is a specific type of memory called ",
". ",
"Some people",
" can recollect just about any event that has transpired (",
"); they are anomalies, and they still can't recollect infancy. They often report their ability being intrusive and difficult.",
"Most people, howev... | [
"Yeah it seems to decay over time. 3 yrs seems to be a time when a lot of people can place an \"earliest\" memory. A lot of people have made the argument that this is also when children start using language a lot more, suggesting the involvement of language in how we organize our memories. No real proof there, thou... | [
"Does episodic memory begin like a kind of moving window where a child forms memories that may be accessible the next day, but will certainly all be gone in years? Is there some approximate age where the average child will begin to form lifelong memories?"
] |
[
"Biologically, what is instinct?"
] | [
false
] | [deleted] | [
"By definition an instinct is NOT taught. Truthfully, we don't know a lot about the exact mechanisms through which they are activated and maintained.",
"Though, we know it is based on specific patterns recognized by the brain that, through years of evolution, have led to its automatic execution of behaviors that ... | [
"Definitely an instinct. Babies are full of clear instinctual behavior, clinging, response to touching the sole of the foot..."
] | [
"I'm not sure if you would classify it as an instinct but babies have a rooting reflex that when touched on the cheek they will start suckling and searching for a breast"
] |
[
"If I threw a rock in a pond of water ,does it make the water evaporate faster (even by little bit) ?"
] | [
false
] | null | [
"yes, but not for the same reason as you're thinking.",
"The rock doesn't \"give the water energy.\" There is a splash because the rock disturbs the surface tension of the water. The rock transfers a certain amount of energy from the deceleration, but that's quickly absorbed by surface tension and gravity from th... | [
"Thank you ! "
] | [
"The rock doesn't \"give the water energy.\"",
"This is not correct. The rest of your comment is correct. The splash has a much larger effect than the energy transfer."
] |
[
"Why is molten iron orange?"
] | [
false
] | Recently there was a discussion between me and my friends and we had a little disagreement about the colour of molten iron. (All beginning with this video here: ) To my understanding: Every object "glows" the same colour at the same temperature. Beginning from red through orange to white depending on how hot they are. Now Iron has a melting point of 1.538 °C. According to wikipedia things should begin to glow white at around 1500°C. Now like the video said molten iron has to be a little bit hotter than the melting point or else it would solidify "instantly" when you try to pour it. So even if the white glowing doesn't happen straight at 1500°C, molten iron, in order to pour it, should be a lot hotter and be white. So here is my question: Why is the colour of molten iron in movies or book descriptions or even when you google "molten iron pictures" always bright orange? Shouldn't it be at least yellow? Thanks a lot guys! :) | [
"Blackbody radiation is caused by temperature, but an object will still absorb and reflect light across the entire spectrum depending on its surface composition.",
"White-hot blackbodies are near 6000ºC not 1500ºC.",
"\n",
"https://en.wikipedia.org/wiki/Black-body_radiation",
"\nKelvin is about 300 more tha... | [
"I thought the whole point to blackbody radiation is that it's only temperature dependent"
] | [
"There is no single \"white\" light. White is the color of something which reflects all colors equally. ",
"1500°C is 1723°K which is a very low color temperature for an illumination source. Common incandescent lamps are around 2500°K. "
] |
[
"Sound has octaves. Does light?"
] | [
false
] | as a tone rises, it reaches a place where it is 'the same' as it was when it started, but higher. Is there any such similar phenomenon with light? edit: Thanks for all the responses. Much appreciated. A lot of info here. | [
"Both light and sound are made of waves, which have a frequency and amplitude. The frequency is the color or pitch, and the amplitude is the loudness or brightness.",
"Our senses of hearing and sight work in quite different ways. This sounds obvious, but the manner in which they differ is critical to this answe... | [
"That is the most accurate answer.",
"I will underscore that both sound and light have analogous frequency properties, but our physiological perception of them works in such a way that for sound, we perceive a certain \"sameness\" for octaves, but we have no such perception for electromagnetic waves. ",
"We sho... | [
"I think that the best way to put it is that in music, an octave is a frequency ratio of 2:1. Similarly, other \"nice-sounding\" note combinations have ratios with small integers in both the numerator and denominator. A fifth (one of the cleanest-sounding note combinations) is a ratio of 3:2, while the fourth (th... |
[
"Is atmospheric pressure increasing due to the increase in Carbon Dioxide in the atmosphere?"
] | [
false
] | null | [
"Not significantly. Carbon dioxide accounts for around 400 parts per million in the atmosphere, up from around 300 ppm at the start of the Industrial Revolution. As a first approximation, that would correspond to about a .01% increase in atmospheric pressure."
] | [
"Burning coal and other fossil fuels just replaces O2 with CO2. Since amount ",
" of gas remains the same ideal gas pressure ",
" doesn't change either."
] | [
"I'm not sure that O2 is simply being replaced by CO2 in the case of burning natural gas. According to this source (",
"http://environ.andrew.cmu.edu/m3/s3/09fossil.shtml",
") the reaction of one mole of methane with two moles of oxygen yields one mole of CO2 and two moles of water vapor. Assuming water vapor c... |
[
"Why do some websites host scripts for their own content on multiple domains?"
] | [
false
] | When using the NoScript addon in Firefox, I often have to allow scripts from multiple domains for a single website, which don't seem like they're for a third-party. They often contain words like "static" and "cdn". For example, Reddit has reddit.com, redditstatic.com, and redditmedia.com. I guess cdn could stand for content delivery network, but if a site needs that kind of redundancy/scalability, why not host everything on a CDN at a single domain? Why bother with more than one? | [
"CDN indeed stands for Content Delivery Network, which typically is a global system of servers (usually managed by a third party provider rather than the website itself) that allows website users to download content from locations that are closer to where they live. A CDN might have datacenters in Europe, America, ... | [
"Hey, thanks for your thorough answer! Unsurprisingly, there's a lot that I failed to consider. If I may ask a follow-up:",
"Is there a reason beyond preference/aesthetics that sub-domains aren't used?"
] | [
"you may (or you may not) using sub-domains for getting well-organized your site.",
"as example: ",
"example.com for your main homepage / portal. ",
"mail.example.com for accessing email on your domain. ",
"forum.example.com for your forum or community page.",
"and so on.... and so on.... ",
"and also, ... |
[
"Is there a chemical that is a 444 on the fire diamond?"
] | [
false
] | null | [
"Meet ",
"tert-Butyl hydroperoxide",
"."
] | [
"The problem with answering this question is that different sources give different ratings. The most reliable probably come from the NIOSH itself, and you can find a list of safety cards from them ",
"here",
". The NFPA 704 code is listed under the \"notes\" section, in the bottom right corner, where available.... | [
"And some metal alkyls like ",
"t-butyl lithium",
"."
] |
[
"How much computer storage would it take to store Graham's number in a notepad file?"
] | [
false
] | [deleted] | [
"To store a number in a notepad file, you need computer memory, which require matter (atoms) to build. For the purpose of this comment, let's say you have a very good memory design and can store a digit per atom. Also you're very rich and can afford 10",
" atoms (that's an entire universe).",
"In that framewor... | [
"This isn't really an answer to your question, but ",
"here",
" is an excellent post about Graham's Number which gives you an idea of the number's insane scale. It's pretty long, but well worth a read.",
"Regarding your actual question, I wonder whether it is possible to write down even the number of bits req... | [
"The math is easy enough to do. Let's assume there are 10",
" atoms in the universe. There have also been approximately 4.33 * 10",
" seconds since the beginning of the universe. (I'll slightly round up here just to be on the safe side -- Graham's number won't sweat it.)",
"Each second, 10",
" atoms beco... |
[
"Can anyone identify these paw prints?"
] | [
false
] | null | [
"They look a little large for a coyote, so I would suspect a larger dog but if you suspect they are red wolf please call US Fish and Wildlife about it. They aren't particularly known to harm livestock, but here is some information regarding them from FWS.",
"https://www.fws.gov/redwolf/",
"http://www.fws.gov/so... | [
"US FWS will have a better idea since rare, threatened, and endangered species information is kept mostly \"secret,\" so if you let them know where, they can look into if it falls into their known locations. Plus if it is an expansion of range, they would really like to know. Either way they'll be happy to be conta... | [
"We contacted the local animal control, but they said they wouldn't do anything unless the animals were nuisance. I doubt it's red wolf, but I just wanted to put it out there. Thanks for the info. "
] |
[
"I've heard a lot of conflicting anecdotes and studies on the connection between violent video games and aggression, what do we KNOW?"
] | [
false
] | Everything I've seen on Reddit thus far has been very dismissive of anything suggesting that there is a connection or correlation between the two. Many even claim that violent video games allow one to release anger, but I'm pretty sure the catharsis theory (taking it out on something/"venting some steam") isn't actually valid in the realm of psychology. What I've learned is that exposure to aggressive material can give a kid a social script. See aggression -> more likely to be aggressive. The psychology textbook I've read is a little outdated and there has likely been new research since then. Is this something we should actually take seriously or is my limited psychology education just plain wrong? | [
"There are two large meta-analysis by Anderson et al done in 2001, and then again in 2010 as a follow-up.",
"\"Violent video game effects on aggression, empathy, and prosocial behavior in eastern and western countries: a meta-analytic review.\"\nAnderson C.A. (2010)",
"The result abstract reads:",
" I also fo... | [
"This is the same Dr. Craig Anderson whose research was the foundation of Brown's (State of California) defense in ",
"Brown et al. v. Entertainment Merchants Association et al.",
". The entire ruling is worth reading, but of particular interest are these two paragraphs:",
"The State’s evidence is not compel... | [
"Please don't take me for a professional source - I am just a student who is currently studying History of Games as part of her major, as well as Game Theory.",
"But may I ask why are you restricting it to ",
" games, rather than 'games' in general, including physical games such as various forms of the 'footbal... |
[
"If Splenda supposedly can't be broken down by the body, does it make your urine taste sweet?"
] | [
false
] | Just making my morning coffee and somehow got to wondering this. | [
"Sucralose isn't very well absorbed by the digestive system, only about 10-15% makes it into the bloodstream and therefore to the urine. The remainder passes unchanged into the feces and out of the body."
] | [
"How do you know it doesn't taste sweet already?"
] | [
"I think you have splenda (sucralose) confused with other artificial sweeteners. It's not a sugar alcohol, it is a substituted disaccharide."
] |
[
"Help with the flat universe theory."
] | [
false
] | The flat universe theory seems to be popular. I've seen the graphs of a "flat universe" but can't comprehend it. What does a "flat universe" mean and what does it have to do with the universe having zero total energy? | [
"\"Flat\" means that the geometry of the Universe is like the Euclidean geometry you might have learned about in high school... the interior angles of triangles add up to 180 degrees, parallel lines never cross, and so on. There are other options - for example, the Universe could be shaped like a three-dimensional ... | [
"Nope, no more than an infinite plane has to have a center."
] | [
"What I really meant by \"almost\" is \"for most reasonable models of how our Universe would work (if it were spherical).\"",
"Remember, the matter content of the Universe is its geometry and its destiny. Different types of matter will result in a cosmology with different properties, for example, which has a diff... |
[
"How abrupt was the average temperature change that occurred in the younger Dryas?"
] | [
false
] | I'm finding lots of different claims on this: some say it was rather gradual and happened at a few tenths of a degree/century, other sources I've found state that the YD actually started and ended very suddenly, to a rate that is very much comparable to that of the current anthropogenic global warming (one whole degree in just a few decades). What does the science say? Would a detailed century-to-century graph of the average temperature in that period show a gradual curve? Or would it show a sudden (almost vertical) drop, then a more or less stable period and eventually a just as sudden rise? | [
"You need to be really careful with data like that because you're only looking at a single ice core from Greenland, which does not reflect global temperature particularly well in this case.",
"There's ",
"reasonable evidence",
" to suggest that the Younger Dryas was predominantly just a northern hemisphere ef... | [
"You're most likely seeing various values for the Younger Dryas Stadial resulting from differing proxies and methods, but also locations around the globe. Noting the cause is important to understanding why the climate was so variable not only from location to location, but across hemispheres. A sudden influx of fre... | [
"Looking at this chart",
", it looks like the temperature rose by 5",
" C in 300 years for the steepest part."
] |
[
"If temperature describes the average energy of particles in a substance, why is it dimensionally different from Joules?"
] | [
false
] | null | [
"Temperature... doesn't really describe that. Temperature is actually pretty difficult to describe analytically; it's so common, though, because it's easy to measure. In this definition, temperature actually describes how much or how fast heat will flow to or from an object. This makes it different from energy."... | [
"Temperature is the average ",
" energy of a single atom/molecule in a substance. The post of FlyingSagittarius shows why, based on interatomic potentials and density, this average kinetic energy does not always translate well to our daily life macroscopic idea of energy.",
"But to answer your question, absolut... | [
"Also, the specific heat (heat capacity) of a material measure how much energy you need to put in the medium to increase it's temperature by 1 degree. For noble gas, the temperature is a direct measure of the translationnal kinetic energy of the atoms. As you add more energy, you get more kinetic energy, and the te... |
[
"Is there an inherent delay in accelerometers?"
] | [
false
] | I was just wondering, because an accelerometer usually contains a strain gauge which is connected to a wheatstone bridge. When an acceleration happens, there is a force on the gauge, but it sure takes some time for the strain gauge to actually get into a force equilibrium? | [
"All the accelerometers I use are piezoelectric. AFAIK, the compression causes an instantaneous current. I imagine there is some small transmission delay.",
"Edit: ",
"Here",
" are the specs of a device from Wilcoxon Research. They quote a 6 deg phase shift at 2.5Hz. I assume they have similar specs for their... | [
"That was absolute. Relative was +/-2. I believe that was worst case, you could contact tech support at Wixcoxon directly to inquire. They are always very helpful and quite well informed. I suggest call, not email, you will get much better results."
] | [
"Ok. My main concern right now are not the exact specs; I am currently reviewing advanced control techniques for PMLM's. One of them was to use acceleration measurements together with the standard encoder data. My thought was, that if the bandwith of the Motor is too fast, the acceleration measurements would introd... |
[
"Is there a term for the smell/feeling you get when your nose has been hit? Also, what causes that?"
] | [
false
] | [deleted] | [
"I think it smells... Metallic"
] | [
"Yeah, I agree, I think it almost smells like blood tastes (like iron)... Maybe that has something to do with it?"
] | [
"No, I meant \"ring your bell\" is the common description of that feeling from getting punched in the nose. But it doesn't sound like a bell, instead it tastes like one. :)"
] |
[
"Why does massage have such pleasing and relaxing effect? What exactly happens to muscles (joints) when they get massaged?"
] | [
false
] | null | [
"Mostly improved lymphatic drainage. But also mechanoreceptor activation that leads to lowered muscle tone/spasm and reduced sensitivity to pain. "
] | [
"Lymphatic flow is driven by muscle activity. Unlike blood which has a centralized pump that powers the whole system, lymphatic ducts use the pressure from the surrounding muscles and a lot of one-way valves to ensure that fluid goes back up toward central circulation. So massage essentially does the same thing, ju... | [
"Is this also why stretching feels really good after you've been sitting down for a long while?"
] |
[
"Do \"antiparticle\" black holes exist? What would happen if a antiparticle entered a \"normal\" particle black hole?"
] | [
false
] | [deleted] | [
"There is no distinction between a black hole formed from coalescing matter and one formed from coalescing antimatter. An incoming object -- whether matter or antimatter -- would increase the mass of the black hole."
] | [
"To expand upon this. Energy has a mass equivalent so even if the matter and antimatter annihilate into energy; it still results in the black hole swallowing some additional mass (and nothing escapes bar Hawking radiation)."
] | [
"Black holes has very few properties, in fact they only have mass, angular momentum and charge. One says that \"black holes have no hair\", and the result is called the no-hair theorem. This means in particular that the type of black hole doesn't depend at all on what it was formed out of: it only keeps track of th... |
[
"Is it possible to liquefy metals using magnets?"
] | [
false
] | Is it possible to use magnets to turn solid metals into a liquid, the likes of mercury? | [
"Yes",
". It's done in industry quite often. ",
"Induction furnaces",
" can get metals very hot very quickly."
] | [
"Just to be clear, the metals become liquid because they get really hot. The magnetic field does not affect the melting temperature of the metal as far as I'm aware."
] | [
"Yes, liquid metals can be magnetized. On a similar note, that's part of a ",
"theory",
" of how Earth's magnetic field arises. I'm not sure where the current research stands on that subject though, it seems like there's still a lot of questions that haven't been answered."
] |
[
"Why do I always get drowsy at 2 pm?"
] | [
false
] | I regularly fall asleep in the middle of class around 1:30 - 2. I sleep fine at night, around 8 hours. What can I do to prevent this? Not even espresso works. | [
"Warning! Simplified Short answer: Human circadian rhythm has a natural increase in sleep drive occuring about 2pm (depending somewhat on the time of year). See ",
"this picture",
"."
] | [
"When I became acquainted with this aspect of the circadian rhythm I tried to figure out a way to integrate this fact about my biology in to my life. I've basically written off 1-2:30 as a time that I cannot be productive at my desk. Here's what works for me. Big moderate GI breakfast, work until 1, gym or physi... | [
"Mammals are napping creatures.",
"Try a 30-minute power nap a little earlier than your class. Anything more or less than about half an hour will leave you feeling groggi(er). ",
"Sleepyti.me",
" is a handy calculator to avoid waking up during REM cycles."
] |
[
"If I clone an animal with spots or stripes, would the cloned animal develop the exact same pattern?"
] | [
false
] | null | [
"This can be a somewhat difficult question, because not all external patterns are controlled in predictable ways. While it is true that between two cloned animals the DNA coding sequence is (or should be) identical, that is not true of epigenetic marks such as DNA methylation, histone modifications, and X chromosom... | [
"It depends on the basis of the expression for the pattern. Some physical characteristics depend on certain proteins present in the mother's egg, so if those proteins aren't in the egg you used to inject the nucleus of the original animal, you might not get the same physical traits. "
] | [
"It greatly depends on the animal being cloned. For some animals, like cats, the expression of colour in their fur depends on how warm they're kept. That's why you get 'pointed' coloured cats, where their paws and ear tips are different colours; those parts of the body tend to be colder, and so do express the pigme... |
[
"Why is it that when I get 9 hours of sleep and wake up at 6AM, I feel so much worse compared to getting the same amount of sleep and waking up at 10AM?"
] | [
false
] | null | [
"Studies have shown that you could go as low as being asleep only 2 hours per day if you'd like. ",
"Could you provide some citations on that?"
] | [
"Studies have shown that you could go as low as being asleep only 2 hours per day if you'd like. ",
"Could you provide some citations on that?"
] | [
"This has to do with your circadian rhythm, which is slightly different for each person. But we do know it goes something like this:",
"The lowpoint of the body is around 3am to 4am. This is when your body temperature is the lowest, all bodyfunctions are down to a minimum. You might know this from going out, that... |
[
"What is the light we are seeing around the black hole picture?"
] | [
false
] | We all know of the black hole. I know quite a bit about space and astronomy but is the light around the black hole the event horizon? | [
"It's the ",
"accretion disk"
] | [
"Not necessarily. That depends on the geometry of the accretion disk. I think the introduction of ",
"this paper",
" should help :)"
] | [
"And the sphere in the middle (black hole) where the dark and light are touching is the event horizon right?"
] |
[
"Does loratadine have an anticholinergic effect?"
] | [
false
] | In , I posted a link to I found, which stated that the antihistamine loratadine ("Claritin") has an anticholinergic effect. Hacker News user jcl posted a link to , which stated that the drug does not have such an effect. We both think this is a weird situation. Which article is correct? (The context is that heavy use of anticholinergic drugs by older people apparently correlates with significantly higher rates of dementia.) | [
"Loratadine does have low levels of anti-cholinergic activity in animal studies: ",
"http://www.ncbi.nlm.nih.gov/pubmed/15627436",
" ",
"This is not likely to lead to a large effect in humans due to low blood-brain barrier permeability but could lead to some side effects from anticholinergic and antihistamin... | [
"The basic trend with antihistamines is the older the antihistamine, the more powerful the anticholinergic effect. Essentially ALL antihistamines have at least some anticholinergic effect, but the newer generations have a much less robust effect in this area. In many cases with the newest antihistamines, the anti... | [
"Please don't advise people to take 4x the recommended dosage of a drug. ",
"Yes, it will cause anticholinergic and unpleasant effects at high dosages. Its irresponsible to take quadruple the amount of any drug. Dosages are worked out using a variety of methods that take into account the clearance, metabolism, ha... |
[
"Are there any examples of an invasive species being introduced to an ecosystem and being beneficial for local flora and fauna?"
] | [
false
] | null | [
"The answer to this depends pretty much entirely on how you want to define \"beneficial\". If you're just looking at the perspective of a single species, then that species could be better off after the introduction of an invasive for a few reasons. For example, if a hypothetical invasive species competes with a p... | [
"everyone else has pretty good comments that highlight how difficult restoration and conservation is when it comes to introduced species. ",
"But, just to clarify a bit:\nInvasive are introduced organisms. This isn't always \"european starlings to united states\" but can even be freshwater fish from the east coas... | [
"Benefit is a human construct. If you introduce a new species into an ecosystem, there are going to be some winners and there are going to be some losers. For example: if you introduce ladybugs into a region plagued by aphids, the aphids, while local, will definitely suffer while plants would benefit. It could be a... |
[
"How much energy is created when a gram of matter is destroyed with an equal amount of antimatter?"
] | [
false
] | Also how much energy is produced when a ton of matter is destroyed with an equal amount of antimatter? | [
"2 grams (one of matter and one of antimatter) are .002kg, and the speed of light is 299,792,458 m/s, so substituting into E=mc",
" you get E=179751035747363.5 J (or roughly 1.8x10",
" J if that is more helpful). That's around 1.5 times the amount of energy released by the atomic bomb dropped on Hiroshima."
] | [
"In matter-antimatter collisions resulting in photon emission, the entire rest mass of the particles is converted to kinetic energy. (",
"http://en.wikipedia.org/wiki/Antimatter",
")",
"Thus, since E=mc",
" we would get 1.8",
"10",
" J/kg)."
] | [
"Wolfram alpha",
" will answer your second question, and any further questions where you just tweak the numbers. It'll also give you the results in understandable results, like the energy of a ton of matter annihilating a ton of antimatter will give energy approximately equal to 1.2 times the energy released in t... |
[
"What percentage of the water you drink turns to urine, and what percentage goes elsewhere?"
] | [
false
] | null | [
"The ",
"Wikipedia Fluid Balance article",
" has a variety of numbers which don't seem entirely consistent, but one set puts urine at 60% (1.5 liters/2.5 intake). ",
"But it varies a lot. Mostly fluid is lost to urine, sweat, and evaporation in your breath. In dry air, including hot dry air but also outdoor... | [
"To add to this answer, the variance carries also into a cellular form, and the gut biome variances. The more adipose (fatty) tissues someone has the more water and other fluids will be retained in those locations. Difference in gut biomes accounts for a decent bit of variance, too. Which is why that wiki article, ... | [
"Yes, I meant more in trying to get an avg % for all people. It's variable how much adipose tissue someone has, and how effective it is to retain fluids."
] |
[
"M.D.'s of Reddit, is it ever too late to go into Medical School in your experience?"
] | [
false
] | I'm 31, working a crap job and have always wanted to go into medicine. The thing that has held me back is that I'm debt free and don't want to owe tons of money. Now I'm wondering if it's just worth the sacrifice to get out of this terrible rut that I'm in. Am I too old? Update: Wow! Thanks so much everyone! With the wealth of information I've gotten (and others in my situation have gotten) I can make a much more informed decision concerning the matter. So, to everyone here, thank you! | [
"Well, if you go into medicine now you'll be an M.D. by 36. If you don't, you'll still be 36."
] | [
"It's not too late, but you'd better be sure that you really, really, really want to become a doctor. You'll be in 200-250K of debt, but you'll be able to pay that off, although that won't be until sometime in your 40s. If you feel that a career in medicine is the only way you'll be happy, then you have to do it... | [
"Why not be a nurse practitioner or a physician's assistant? Far less school, far less debt, far less stress and you're helping people in the same way."
] |
[
"Is it reasonably conceivable that there are large planets in the universe where there are lifeforms that are thousands or even hundreds of thousands of times the size of humans? Or would some physical law prevent this?"
] | [
false
] | [deleted] | [
"There are animals on Earth thousands of times bigger than humans! Blue whales are about 2-3 thousand times the mass of humans. The largest organism on Earth (known) is a fungus, Armillaria solidipes, the largest of which is at least 2.4 miles across. ",
"If you want to restrain yourself to more conventional anim... | [
"Imxbftw is correct about whales. But in general, animals that walk must be smaller on a larger planet because greater gravity would limit size, not enhance it. For instance, animals on our planet that are (or were) bigger than us by any significant ratio must have MUCH larger legs to support their mass. ",
"A SM... | [
"Wasn't the atmosphere high in oxygen - which lead the insects to grow so large ?"
] |
[
"From an evolutionist standpoint, if warmth is necessary for survival, why did humans evolve without fur?"
] | [
false
] | it just seems counterproductive to me. if we started out as monkeys why would we lose that warmth. | [
"We lived in warm places and didn't need fur to live. Losing it made us cool down better when exercising, enabling us to endurance-hunt other animals who cannot exert themselves as much continuously over a long time."
] | [
"Because staying cool can be more necessary for survival than staying warm is if you live in a hot place or need to run to hunt and get your food. Both of these were likely the case for very early humans. So the assumption that warmth is good for survival is the issue here, not some unusual case of how evolution wo... | [
"Humans didn't evolve without fur. Humans evolved ",
" fur, then we learned to steal fur from animals for warmth, and after that point it was actually disadvantageous rather than advantageous to have our own fur."
] |
[
"What is the hardware used for quantum computing and how does it work?"
] | [
false
] | null | [
"Quantum computing is currently done theoretically and experimentally on multiple kinds of hardware. Each kind of quantum computer hardware setup is called a platform for quantum computing. Each have their own strengths and weaknesses, however, the currently most popular seems to be superconducting circuits. These ... | [
"Do you know what IBM is doing? Apparently they have on the order of a few hundred qubits now, or something like that, what does that entail and how did they get up that fast?"
] | [
"I read up on it yesterday after reading your question, and I completely forgot to answer you. It seems IBM is also working with the superconducting electrical circuit type qubits. They say that what makes their quantum processor work with so many qubits is simply many small improvements leading to big steps. Two t... |
[
"If doctors/surgeons can reattach certain body parts, mend bones, etc....why can't they reattach spinal cords?"
] | [
false
] | Say, for a paraplegic or quadriplegic patient. | [
"Imagine your spinal cord as an incredibly dense bundle of wires that carry information between your peripheral body to your central nervous system. If you snip that bundle of wires, simply reattaching the two ends together wouldn't restore communication. ",
"Some communication might be preserved, and maybe a f... | [
"The spinal cord isn't a discrete whole, it contains millions of neurones travelling in multiple pathways. Repairing a severed spinal cord would require reattaching each individual neurone correctly which we simply don't have the technology to do.",
"Even if we were able to do this, the part of the neurone that h... | [
"and maybe a few of the ends of the wires would find each other after a bit...",
"Does that mean all our nerves have a unique signature, so there is some chance for them to reconnect?"
] |
[
"With the announcement of Deep Space's plans to begin mining asteroids within the next decade, is asteroid mining a feasible technology? Furthermore, could it begin our venture into colonizing outer space?"
] | [
false
] | null | [
"The technology exists but it would be very, very expensive. I believe the most significant things we have returned to Earth (besides moon rocks) are flecks of dust from comets. There have been missions that have landed on (and even blown up) asteroids. I believe the goal of Deep Space, in addition to bringing back... | [
"\"Explosion\" does not imply combustion. In this particular case, a 375 kg chunk of copper was slammed into the comet at a speed of 10.3 km/s."
] | [
"What asteroids have been \"blown up\"?"
] |
[
"Why do some people have more 'energy' than others? In other words, is there a genetic difference between the person able to be active 100 hours a week versus the person who is barely able to work part time?"
] | [
false
] | [deleted] | [
"\"Energy\" is a very broad term, but in general there are a number of factors that affect your \"energy\" or \"vigor\". A few things that affect overall vigor are:",
"-Sleep Quality/duration\n-Hormone regulation\n-Diet\n-Activity (excercise)\n-Mood\n-Environmental factors ",
"Now I will not claim that this is... | [
"This is an incredibly complex issue. I can't provide a concise answer which would be meaningful (there are ",
"multiple",
" ",
"lengthy",
" ",
"reviews",
" on the subject of intraspecific variation in voluntary activity), but here are some traits which are correlated to activity levels, or just relate... | [
"You are right to be shy of generalizations, but it appears that there is a strong genetic component. It is unclear whether or not ADHD lies along the spectrum of activity, but if it does, then it would be apperent that there is such a thing as too much of a good thing (in this case, propensity for activity)."
] |
[
"How does a Magnetron work?"
] | [
false
] | So, I was curious about microwaves, and I looked up how they work, and after reaching the point about how magnetrons make microwaves, I didn't really see any simple or conceptual explanation as to how they work.... I realize that they make microwaves, but I don't see how. | [
"Without looking anything up, a magnetron is a circular device used to spin electrons in a circular motion. The magnetron has cavities that create resonance. These cavities are spaced to create a particular frequency and there is an exit port to send the energy down a waveguide. From what I understand, the magne... | [
"So is it basically a coil inside a tuned set of resonance chambers?",
"Thank you for replying, by the way. =)"
] | [
"No problem. I forgot to mention the 2 magnets above and below the cavity that are used to circulate the electrons in the air cavity (not a coil). ",
"Here is an image of a magnetron cut in half on a band saw:"
] |
[
"Does the expansion of our universe have an effect on the size of black holes?"
] | [
false
] | [deleted] | [
"Nope - the expansion of the universe has zero effect on any object that is bound, whether through gravity, electromagnetic force, or so on."
] | [
"Close but not entirely correct. The expansion of the universe ",
" in any portion of the universe for which the mass density is significantly higher than the large scale average mass density."
] | [
"What if you have two spheres located a very large distance away from each other, so that their gravitational pull is equal to the \"ideal\" rate of expansion... could you construct such a scenario where the two spheres remain at a fixed distance over time? It seems this point must (theoretically) exist, since at c... |
[
"Could you \"predict\" all of chemistry using only Quantum Mechanics?"
] | [
false
] | [deleted] | [
"In principle, yes. In practice, it's extremely hard. All but the simplest possible atoms are quantum-many body systems, and solving a quantum many-body problem is very difficult. ",
"There are lots of different approximation methods that one can use, like ab initio methods, configuration interaction methods (\"s... | [
"This is basically all of theoretical quantum chemistry. But they're using the kinds of approximations I listed above."
] | [
"This is basically all of theoretical quantum chemistry. But they're using the kinds of approximations I listed above."
] |
[
"How are we able to work with things on the atomic scale?"
] | [
false
] | How on earth are we able to move individual atoms/manipulate them in any way? Aside from atoms, something that never made sense to me is transistors. Those things that make computers run are to my knowledge, the size of electrons! How are we able to manufacture them and precisely make electronic parts such as CPUs and whatnot with things the size of electrons and not accidentally break them by blowing a little on them? Even more fascinating is how these things don't break just by touching them. As an example, here's a video about some guy who tried to take a picture of an atom. (skip to 0:40). It says "he placed an atom between two rods and took a picture of it". How? If anyone can help make sense of this that would be really cool, I've never understood how this stuff is possible. | [
"Techniques to image and manipulate single atoms are very well established within the surface science community. Scanning tunnelling microscopy (STM, ",
"[1] scientific article",
", ",
"[2] wiki",
") and atomic force microscopy (AFM, ",
"[1] scientific article",
", ",
"[2] wiki",
") are the staple t... | [
"Wow, thanks for the detailed explanation and links, I'll be sure to check them out! This makes a lot of sense"
] | [
"The smallest features in most electronic devices are around ~10 nanometers, that's still thousands to tens of thousands of atoms. These features don't break partially because they're made from strong materials (metal, glass, silicon), but also because of their aspect ratios. A large tissue is very easy to rip, eve... |
[
"Why is the actual ratio of base pairs in DNA (C and G, A and T) not 1:1?"
] | [
false
] | According to Chargaff's rules, shouldn't the ratio of base pairs be the same? On the , the proportion of bases in humans is A:29.3 G:20.7 C:20.0 T:30.0. There is 0.7% of guanosine that seems to be unpaired with cytosine. | [
"Yes, the ratio of base pairs are the same. The Wikipedia page is reporting what Chargaff himself measured in the 40s and 50s using chromotography, which is subject to experimental error (and in fact, many researchers discounted Chargaff's results entirely as being a consequence of error).",
"In release 36.2 of t... | [
"Additionally, part of the reason why the G's and T's are slightly higher in frequency than the A's and C's, is because the telomeres are G-T rich (many repeats of the sequence TTAGGG), and the ends of the telomeres do not always have a complimentary strand."
] | [
"While this doesn't address OP's question, the effect you're referring to is cytosine deamination which converts cytosine->uracil and methyl-cytosine -> thymine."
] |
[
"With current technology plus the information gained from the particle with qualities like a Higgs boson, would a mass fabricator be possible?"
] | [
false
] | With current technology plus the information gained from the particle with qualities like a Higgs boson, would a mass fabricator be possible? Is a machine that creates mass from energy possible to be made in the future? | [
"We can already create mass from energy via particle accelerators as some of the energy transforms into subatomic particles. And, to mention on the other comments: it does take a tremendous amount of energy to create them."
] | [
"Look up wikipedia, this is how particle accelerators work and it is commonly understood. They do produce mass via the energy input, resulting in a net gain of mass."
] | [
"Read the last sentence. Antimatter can be collected in a Penning trap or a magneto-optical trap."
] |
[
"What scientific discovery, made in the last 20 years, do you think is both very important and under-appreciated by the general public?"
] | [
false
] | null | [
"The role of probiotics in overall health and immune system, and not just the regularity you see from yogurt. There are so many strains, and still yet so little research done. ",
"Some people suffering from UC and Crohn's etc have responded wonderfully to the correct type of bacteria or yeast. Fecal transplant... | [
"Maybe optogenetics. In combination with nanotechnology, it's now enabling us to acutely control biochemistry, such as to turn the feeling of thirst on or off, a memory on or off, a muscle to contract or relax, an auditory sensation, or the production of serotonin. ",
"Potentially very beneficial. And potentially... | [
"We can directly see atoms and chemical bonds using ",
"AFM",
". From what I've seen done with AFM, new developments are expected. I haven't seen this widely published in popular press although it's popular within the field."
] |
[
"When you lose weight, where does the weight (/mass) go?"
] | [
false
] | Presumably the toilet, but I'm interested in the specifics. | [
"You breath most of it out as CO2. ",
"This ",
"article in the BMJ",
" (the British Medical Journal) calculates that if you lose 10 kg of fat, 8.4 kg of it is lost as CO2 that you breath out, with 1.6 kg of it becoming water. I can't do subscripts here so calling fat \"C55-H104-O6\" the equation they show i... | [
"Not what you would expect.",
"Carbon dioxide you breathe out, and water through sweat, urine, breath, etc.",
"\"fat\" cells are mostly just big blobs of triglycerides, which are long branched molecules of Carbon Hydrogen and a little Oxygen.",
"The carbon and hydrogen combine with oxygen you breathe to form ... | [
"Thanks so much! I was not expecting that. It reminds me of Feynman's famous lecture about trees being made of air."
] |
[
"What does the brain do while \"clinically dead\" during procedures like Deep Hypothermic Circulatory Arrest?"
] | [
false
] | null | [
"From some knowledge, but be aware I am no expert. Cooling down the body in this form causes it to use much less energy than in its base state. By doing this they basically cause the brain to use a lot less resources during the procedure. This is important because if the brain is using less resources it has longer ... | [
"For a simplified explanation, the brain doesn't just die instantly as soon as it's without oxygen (though you will lose consciousness), and the majority of the damage is caused once oxygen is restored and the cells have already initiated a self-destruct of sorts. It takes a few minutes to get to that point at nor... | [
"This is correct. The energy consumption of a fully functioning brain is quite high and neurons can die off very quickly if their supply is disturbed, so reducing the rate at which they consume it helps keep everything intact.",
"As for what happens to memories, they shouldn't affected because they aren't directl... |
[
"How did the blood clotting cascade evolve?"
] | [
false
] | As a student of both pharmacology and evolution I often wondered about the molecular evolution of our various biological pathways. The one which always sparked debate between my professors was the Blood Clotting Cascade. It is an argument used by intelligent design, saying that some systems are too to simply evolve. With the pathway consisting of over twenty proteins, and if any one were not present then the pathway no longer works (e.g. haemophiliacs). What I've found online are a number of ill-made powerpoints and citationless websites. Does anyone have some concrete scientific papers or journals which can shed some light on the matter? | [
"This ",
"paper",
" directly addresses your question. In short, the clotting cascade is not, as Intelligent Design/Creationism proponents would have you believe, irreducibly complex. Many species have been found with functional clotting cascades that are missing one or several of the clotting factors. Additiona... | [
"To be honest, I don't quite follow your question. The eye is not irreducibly complex. I'll leave it to ",
"baby-faced Dawkins",
" to explain the evolution of the eye."
] | [
"Basically, it's repeated application of gene duplication + specialization.",
"You start out with one protein that does everything: detect the needs to clot and triggers fibrin polymerization.",
"The first thing that evolves is self-catalyzing. The protein also triggers copies of itself, which amplifies its ef... |
[
"Can fungi have cancer?"
] | [
false
] | When I first developed an interest in biology and learned what cancer is, on a physiological basis, I wondered whether plants can suffer from it. I looked it up and read about trees growing tumors. It made sense that plant cells, though significantly different in many ways from animal cells, could still replicate in an out-of-control manner since they are both fundamentally controlled by DNA. A few years back, the question progressed: can fungi have cancer? If the other two multicellular kingdoms could, why not fungi? I tried to Google it and look it up in books, but I found absolutely no information on the subject. I thought an interesting experiment would be to get some species of mold, expose it to strong mutagens, and observe the reaction (if any). I, however, do not have effective enough safety equipment in the chemistry lab in my basement or access to the requisite chemicals (the mold would be easy enough to come by :P ). So my question is: can fungi suffer from some form of cancer? Do they have mechanisms of some variety to suppress irregular growth, does their lack of a vascular system prevent the spread of malignancies, or does their network of hyphae fundamentally not support a disease like cancer due to its structure? I would imagine the latter two are true, but shouldn't something like a single tumor still be able to arise at some point in the fungal network, growing from one improperly replicated cell, even if it cannot metastasize elsewhere? | [
"Thank you, to whoever down voted this post to 0 for no apparent reason..."
] | [
"I'm not an expert on fungal multicellular structures, but since no one else is answering I'll throw some ideas out. ",
"During the single-cell stage of fungi, cancer can't possibly exist, because \"out-of-control\" growth is the default, and it's advantageous to divide as quickly as possible.",
"At some point ... | [
"Thank you very much! That would make a lot of sense. The fact that they aggregate rather than actively dividing is a convincing argument."
] |
[
"Can you explain in simple terms, why can nothing travel faster than light?"
] | [
false
] | null | [
"For me, the simplest way to explain it is that experimentally, we have measured the speed of light to be always the same value - 3 x 10",
" m/s, otherwise known as c. What does that mean?",
"It means that if you shoot a beam of light, it will always be traveling away from you at c. Even if you have a rocket sh... | [
"Long story short, is that you are measuring the speed of light in ",
" per ",
". These are two variables that we have to agree on first. But what happens if we don’t agree on how far a mile is, or how long an hour takes? We can both agree that a mile is 5280 feet, but what if our rulers are different lengths t... | [
"Long story short, is that you are measuring the speed of light in ",
" per ",
". These are two variables that we have to agree on first. But what happens if we don’t agree on how far a mile is, or how long an hour takes? We can both agree that a mile is 5280 feet, but what if our rulers are different lengths t... |
[
"Can we domesticate bears like we did wolves?"
] | [
false
] | The Soviets managed to over 50 years. I was wondering if the same can be done for any animal, or specifically the bear. I want a pet bear and I want science to give it to me! | [
"After googling about it would seem that it might take 10 times as long if you could mimic the same method the soviets did and have them work on bears. ",
"This is because a silver fox reaches maturity at about 1 year old, whereas grizzlies reach maturity at about 5 years old. ",
"So basically, we should have s... | [
"Domestication",
" is easier in animals that are already highly social. This a bonus because you crave being around others. Social animals also have leaders, and humans can take the place of the \"alpha\" individual. Generation time is also important, the faster a species breeds the faster you can select for the ... | [
"http://www.youtube.com/watch?v=CVMBdi4dgME",
"\nThis guy seems to have managed it, not very scientific but a decent example."
] |
[
"Does the space shuttle have the technical capability to escape earth's orbit?"
] | [
false
] | Could the shuttle orbit the moon for a few days? What technical challenges are there to accomplish this? | [
"If the entire bay was used for fuel, it's possible, but you wouldn't get to the moon, or more accurately, you wouldn't return... Alternately, you might be able to stick another solid rocket booster on it, and then you might be able to use less of the propellant in the liquid fuel tank you take up with you, but thi... | [
"Whoa. I didn't realize how big all those other rockets were in comparison to the space shuttle. Thanks for the response"
] | [
"Imagine how loud the Saturn V is. \nThat huge cloud of white you see on Shuttle launches is actually a ground-based steam wall that shields watchers from the 240+ decibel explosion going on in the engines. "
] |
[
"When one is decapitated, what brain functions actually remain momentarily? Do you actually have a few seconds to think about it?"
] | [
false
] | null | [
"Just to address the one point: even if your voicebox were intact, you could not talk. You no longer have any lungs to push air across the larynx."
] | [
"There was an AMA recently about a guy who had his throat slit. According to him, he had only two or three seconds (according to witnesses, but it seemed a lot longer to him) before he fell unconscious. ",
"Both decapitation and having ones throat slit result in a catastrophic plummet in blood volume in the brain... | [
"there were some ",
"\"experiments\" done during french revolution",
", that suggest that the head may still be alive to some extent several seconds after decapitation. but without access to lungs, you most certainly cannot make any sounds.",
"edit: i may want to take that back. the reference on the wiki seam... |
[
"Why do polarised sunglasses make some screens difficult to read?"
] | [
false
] | I'm a crane driver and find it hard to look at my instrument screens when wearing my polarised sunnies. It's difficult having to choose between reading my vitals and avoiding sun strike. | [
"It's because those screens also work through polarization.",
"Polarized sunglasses work by filtering horizontally polarized light, which is common in reflections of the sun (like off the ocean or snow). ",
"TN-style LCDs work by having a backlight, a polarizing filter, a thin film that can twist the light, and... | [
"To add on to this I would suggest purchasing a pair of UV400 shades that aren't polarized and see how you get on. You'll likely notice more light (or less darkness, if you prefer) off of polarized sources such as bodies of water or panes of glass but overall the impact could be fairly slight and afford you the abi... | [
"So, in theory, you could align the glasses just right such that you can perfectly see the screen, while keeping the glasses on?"
] |
[
"Why is it that in so many species the female is the larger/more dominant one, yet human males are built much bigger and stronger than females?"
] | [
false
] | null | [
"What you're asking about is called sexual size dimorphism; that just means that there is a difference in the average size of the sexes. In most species sexual size dimorphism is the result of trade-offs between selection for fecundity or competition and selection for resource limitation and energy expenditure. ... | [
"Humans and chimps show only modest dimorphism (as far as apes go) but relatively large testicles; these features appear to be correlated to serial monogamous or polygamous mating strategies both humans and bonobos display very, very little male on male aggresion with regards mate competition.",
"I'm not sure thi... | [
"I'm not sure this is accurate. In terms of testicle-body mass ratio, humans are much closer to gorillas than to chimps. If you plot these ratios for different primates[1] , you can see that humans are much less different from gorillas than they are from either species of chimpanzee. In fact, most primates are in a... |
[
"Why does staring at a bright light help me sneeze?"
] | [
false
] | For my whole life, any time I've felt the urge to sneeze but couldn't get it out I've looked at the brightest light I could find. This almost ALWAYS helps, but I've never know why. How does photo-receptor stimulation lead to a sinus cavity response? | [
"This is known as the ",
"photic sneeze reflex",
", and it occurs in about a quarter of people. However, the reason for it is not currently well understood - the linked article discusses a few of the current theories."
] | [
"The one theory I've heard that makes sense is that you only really need this reflex once in your life. When you are born, you come into the bright light and you sneeze to clear the amniotic fluid out of your nose. Then you are stuck with the reflex for life."
] | [
"But what about children born at night (not at a hospital)?"
] |
[
"When you have antibodies for COVID, do repeated exposures to sources of the virus \"refresh\" the timer on your immunity?"
] | [
false
] | null | [
"We don’t know what the timer on immunity, from natural infection or from vaccines, actually is yet; it may be quite long (several years), since early testing several months after vaccination only showed a very slow drop off. ",
"Re-exposure to antigen acts as a booster. That’s true whether the antigen comes in t... | [
"Would like to add that there are actually different vaccines targeting the virus in different ways, each with their own \"shelf life\". For example, we may have 1 vaccine right now that has 1 particular kind of antibody, but if that virus mutates* that antibody may no longer stop that particular virus, because yo... | [
"Just a quick note: the reason the tetanus booster is every 10 years is because that's only as long as the vaccine efficiency was tested for. It's quite possible that it lasts much longer and I've heard some suggest it could actually last up to 30 years before needing a booster (that's not to say you shouldn't get ... |
[
"Would a clump of radioactive Uranium decay slower if accelerated to relativistic speeds?"
] | [
false
] | I take it Uranium has a specific decay rate. If a clump of it was accelerated to say 0.9c, then time would be slower from the Uranium's perspective. Therefore, from the observer's point of view, would the decay rate of Uranium decrease? If I am right about this, has this method been used to gain access to particles or elements that decay too quickly when at rest? | [
"Yes. This is the reason why it is possible to observe muons (~ 10",
" s life) that result from cosmic ray interactions in the upper atmosphere.",
"More info ",
"http://en.wikipedia.org/wiki/Muon#Muon_sources"
] | [
"http://en.wikipedia.org/wiki/Large_Hadron_Collider#Design",
"At this energy the protons have a Lorentz factor of about 7,500 and move at about 0.999999991 c, or about 3 metres per second slower than the speed of light (c)."
] | [
"If I am right about this, has this method been used to gain access to particles or elements that decay too quickly when at rest?",
"This is how particle accelerators work. So yes."
] |
[
"Laser scientists: What are you working on?"
] | [
false
] | null | [
"Smaller, but with more power. \nBy shooting them. \nAlmost all wavelengths are now accessible through semiconductor lasers, quantum cascade lasers and quantum dots (to name a few). \nCommercial applications will certainly grow, but probably not in leaps and bounds the way one would expect. The real frontier is at ... | [
"I imagine most people can't talk about their specific projects as it's typically proprietary or classified. Sharing technical info or project status is typically a big no-no. I recently got out of the business but can answer a few of these.",
"No cats.",
"Disc readers are a function of wavelength. The short... | [
"Yes actually, alternate forms (beyond traditional Gaussian) of solutions to the wave equation yield interesting possibilities that allow such interesting possibilities as laser beams that bend in mid air.",
"Please. Please do this."
] |
[
"Why do we dream?"
] | [
false
] | Why do I forget the dream? | [
"'most everything'? Do you have evidence for this, or are we armchair debating?",
"From the armchair, it would seem that not every feature needs to have utility. Evolution is not perfect, it's only been at it for a finite amount of time, there is inherent randomness.",
"Some traits may be side effects of some o... | [
"A class I once took described dreams as being a way for our minds to digest all of the new information taken in during the day. This is why babies sleep so much (and dream for nearly all of it)...they have so much new information to process. "
] | [
"There is an episode of the excellent Radiolab about sleep in general, with a segment on dreams, here: ",
"http://www.radiolab.org/2007/may/24/"
] |
[
"Can diseases caused by viruses with location-specific infection sites worsen with subsequent contact with an infection source?"
] | [
false
] | This is a dual-faceted question. The first question related to auto-inoculation - the second, related to re-infection / superinfection. Some viruses have location-specific infection sites that have some sort of activity persistence based on the infection site long after the initial infection. For example: my understanding is that herpes infects at a specific location, and then migrates to nearby ganglia - reactivation of the virus is therefore related to the original infection site (or, more specifically, originating from the ganglia nearby). In another example, (again, from my understanding,) HPV infections that cause skin warts are centered in one specific area, with the benign tumors / warts associated with the infection located somewhere above the basement membrane of the epithelium above where the initial infection site was located. Firstly: can auto-inoculation occur in these cases, where an infected person spreads an initial infection to new infection sites? I am almost positive this is the case, however, at what point does the auto-immune response limit / prevent this from occuring? What is the difference between a disease that can systemically affect the body and has no subsequent activity that is location specific (such as the flu), but can be completely eliminated by an auto-immune response and a disease such as that described above? Secondly: can subsequent contact (example: regular contact with an infected partner over weeks / months / years) with an infection source infected with the same virus worsen an individual's condition, insofar as creating additional "infection sites" (such as infecting additional areas of the body with the same, already contracted virus)? Otherwise, does the auto-immune response somehow protect from additional sites becoming infected beyond the initial infection sites, even if the auto-immune response can not actually completely remove the virus introduced via the initial infection site? I expect this answer will be similar to the first, but I am not sure. Some reference text (for HSV/herpes): Quick follow-up: does verbiage exist to distinguish between viruses that act primarily systemically (flu / HIV) versus viruses that act on a more localized level (HPV, HSV)? Knowing this would have aided my research, but I did not come across any wording that helped to break the topic down in this manner. THANK YOU. | [
"You're wrong and you should stop posting information about anything. This kind of misinformation contributes to the prevalence. ",
"From the CDC factsheet: \"HSV-1 infection of the genitals is caused by mouth to genital or genital to genital contact with a person who has HSV-1 infection\"",
"http://www.cdc.gov... | [
"You're wrong and you should stop posting information about anything. This kind of misinformation contributes to the prevalence. ",
"From the CDC factsheet: \"HSV-1 infection of the genitals is caused by mouth to genital or genital to genital contact with a person who has HSV-1 infection\"",
"http://www.cdc.gov... | [
"Wow, this is....this is completely false. Please delete this comment so that no one is dumb enough to believe it.",
"Both types of HSV can spread to mouth or genitals. I will say it again: BOTH TYPES OF HSV CAN SPREAD TO MOUTH OR GENITALS"
] |
[
"Why can't we 're-start' dead cells?"
] | [
false
] | I'm specifically curious about cells that have died from a lack of oxygen, I'm aware that this can cause a buildup of toxins that can change pH and de-regulate enzymes, but I don't see how that could structurally compromise the cell - presumably all the necessary parts for, say, a neuron, are still present if it suffocates. It seems to me like the line between life and death for a cell is less clear for a cell than for a person, and in certain circumstances it seems there is so little difference between a dead and living cell that a flush of the cytoplasm or a rebalance of the pH could get it going again, yet as far as I know we don't do this, why? | [
"I'm guessing it's something to do with apoptosis, 'Programmed cell death'. By the time a cell has been compromised somewhat, it will kill itself; I'm guessing that there'd be no point in attempting to resurrect cells in a being where the cells most affected by the cause of death have already destroyed themselves t... | [
"Entropy. Cells are constantly rebuilding bits of themselves that have spontaneously degraded or have been damaged by some force (oxidizing agents, radiation, physical strain). When they die, bits begin to degrade but aren't fixed. The most damaging to continued cell function are the cellular membrane and the DN... | [
"The most immediate effect of lack of oxygen to a cell is lack of ability to efficiently produce energy (ATP). The cell could still produce energy with a low level of efficiency via fermentation of glucose (Im assuming you are referring to human cells) Fermentation leads to the production of lactic acid and when it... |
[
"Does the Da Vinci surgical robot have force feedback? If not, why not?"
] | [
false
] | null | [
"There is no force feedback. ",
"The point of the robot is to give the surgeon precise and predictable control of the instruments. If the resistance of the joysticks varied, or (worse) if they had \"twitch\" or \"rumble\" like some video games do, control would not be as precise. "
] | [
"Haptic feedback is more than just twitches or rumbles, it can act like a ruler allowing the operator to cut a perfectly straight line (or along any predefined 3d curve) or prevent them from moving the robot anywhere it might cause damage. The da vinci robot can certainly benefit from using a haptic joystick, howev... | [
"Motion correction and range limitation are not the same thing as force feedback. You can do either or both of those with having to apply a force back to the control. "
] |
[
"Why can't we create any material (with any properties), substance, or chemical reaction we want?"
] | [
false
] | [deleted] | [
"In short, because chemistry is ",
". Even for chemists.",
"Because your question is so broad it's hard to be specific, but we are limited by the availability of the correct atoms and molecules, and the limits of chemical bonds. For example, we can't make a plastic that can handle 1000 C, because at that temp... | [
"This was actually tried in the late 1990's and is still being done to a certain extent, it's called ",
"Combinatorial Synthesis",
" and the consensus amongst chemists is that it has not lived up to it's promise. (In several incarnations it has been a complete failure, notably the pharmaceutical industry.) ",
... | [
"This was actually tried in the late 1990's and is still being done to a certain extent, it's called ",
"Combinatorial Synthesis",
" and the consensus amongst chemists is that it has not lived up to it's promise. (In several incarnations it has been a complete failure, notably the pharmaceutical industry.) ",
... |
[
"Does learning new information make your brain weigh more?"
] | [
false
] | So I've been told that the brain grows new connections as it learns. As I understand it, the enzyme cypin helps to form new dendrites to conduct electrochemical signals between neurons. So, since these connections are physical, even if only on a micro level, doesn't that mean that your brain literally weighs more after you learn new information? If so, can this weight be measured in any quantifiable way, considering the weight differences caused by moisture evaporating or skin cells shedding off a subject? | [
"Long term potentiation is the term for the molecular mechanism of memory. Once you are an adult the main change that takes place in neurons is actually at the synapse. This has less to do with learning new information and more to do with repeated rehearsal of information, strengthening the connections which alread... | [
"Thanks for replying! So synapses aren't formed when adults learn information, just strengthened? Strengthening is therefore an addition of mass, though admittedly at an even smaller scale than synapse creation.",
"When it comes to strengthening and weakening connections countering each other, I see what you mean... | [
"Admittedly it's possible, depending how small an amount of mass you consider significant, I guess it's inevitable. The supporting cells outnumber neurons 9 to 1 and they are replaced through programmed cell death, so they would have the largest effect in changing mass but it has nothing to do with learning. The br... |
[
"Are slime molds edible? And if so, what would they taste like?"
] | [
false
] | What kind of flavour and mouthfeel do slime molds have? I have read that dog vomit slime mold, Fuligo septica, was used as a food source by some Native Americans. | [
"Finally something on Reddit for which there is no expert. Either that, or nobody wants to come forward with the myriad culinary possibilities that open up upon further exploration of slime mold."
] | [
"Well, ",
"foretopsail",
" is one of the panelists and he is an expert in historic cooking but also in maritime archaeology, perhaps he can provide some insights about the culinary properties of slime molds."
] | [
"I'm pretty sure at least some of them are highly toxic. I doubt you'll be able to find someone who knows for sure.",
"Good luck!"
] |
[
"In the equation: E(photon) = E(binding energy) + E(electron), why some refer to E(electron) as the electron kinetic energy and others as the energy of the electron?"
] | [
false
] | null | [
"That’s the kinetic energy of the emitted electron."
] | [
"Thanks,",
"\ndoes it refer to the translational kinetic energy? because the electron has spin regardless of the photon energy"
] | [
"does it refer to the translational kinetic energy?",
"Yes."
] |
[
"VASIMR type engines, what are the best propellants and why?"
] | [
false
] | I'm doing research for an upcoming novel. I've been researching VASIMR engines but I haven't found a great deal of specifics with regard to fuel. I know hydrogen seemed like a nice idea due to its abundance in the solar system (and everywhere), but the latest prototypes use either argon, iirc. As I understand it, a heavy element that can be excited with lots of energy for the highest possible exhaust velocity would be best for power output and delta-V. Would it stand to reason that a heavier gas would work better? Does the problem with H or He stem from them being too light to store reasonably on board even in liquid form, like a much larger and heavier tank vs a smaller lighter tank to hold the same weight of a heavier gas? Would Kr and Xe work better if they could be gathered in sufficient amounts? Or conversely, would H, He be better by simply inflating the tank size to store an appropriate tonnage of fuel? The question here applies two fold, i.e., if one is better for deep space where another would be better for LEO. Thank you | [
"Helium is a pain in the rear to keep in a tank. The small atom goes right around seals, and even straight through many materials. That's why helium birthday balloons drain faster than ones filled with air. Argon/Xenon are larger, so they leak less, and ionization energies go down as the atom gets bigger. Heavier g... | [
"Thanks, that was very helpful."
] | [
"Update: All research that I've turned up to this point says that heavier gasses are better for LEO, and H or He are better for deep space, but no real reasoning given as to why. I assume the ability to refuel during mission makes it better, but you would think boosting the spacestation to hold its orbit would be... |
[
"Why don't electrons fall into the nucleus?"
] | [
false
] | Is there a force that prevents them from doing that? is it the Pauli Exclusion Principle? Obviously I have no idea what I'm talking about, so fire away. | [
"Have a look at ",
"this page",
", it describes the shapes of the orbitals (i.e. the \"probability clouds\" of where the electron can be found), and it even has a section titled ",
"\"Why doesn't the electron fall into the nucleus?\"",
".",
"Note, however, that the pictures of the orbitals there are alrea... | [
"The Pauli Exclusion Principle only restricts electron configuration when there's more than one electron involved, so it couldn't explain what happens in atoms with a single electron. ",
"The answer is the Heisenberg Uncertainty Principle. An electron has a probability of being anywhere within an atom at a give... | [
"Isn't this what happens in the formation of a neutron star? "
] |
[
"A recent set of papers suggests that our common genetic ancestors \"mitochondrial Eve\" and \"Y-chromosome Adam\" may have existed close together in an evolutionary timeline. Why was this not expected?"
] | [
false
] | [deleted] | [
"So, ancestry gets a little confusing sometimes. There are multiple things going on here, and we should be careful to separate them all. It's also made worse by the media obsession with \"mitochondrial Eve\" and \"Y chromosome Adam\", which are not especially helpful metaphors.",
"There are essentially two ways t... | [
"That's not true for a few reasons. The first is that \"mitochondrial eve\" may very well have lived more recently than \"Y Adam\".",
"But more fundamentally, each of these individuals is only defined with respect to individuals alive today. The way to find mitochondrial eve is to start with every woman alive tod... | [
"Think about it this way: Y-chromosome Adam could have mated with two unrelated women. The women's latest common ancestor is Mitochondrial Eve."
] |
[
"Do identical objects at different temperatures cool at the same rate?"
] | [
false
] | Consider two identical iron blocks. If one is heated to say 900 degrees and the other to 500 degrees, and left in identical rooms at identical temperatures, would they cool at the same rate? After about 15 minutes, if the first block cools to 850 degrees, would the second object be at 450 degrees? | [
"No they do not cool at the same rate. The rate of cooling is proportional to the difference in temperature between the ambient air and the temperature of the block. This means that the greater the difference in block temperature to ambient air temperature results in a faster rate of cooling. This also indicates... | [
"Since temperature is an aggregate and noisy, spatially-varying quantity, the object reaches a level that is practically indistinguishable from ambient room temperature."
] | [
"There are three main methods of heat transfer, ",
"convection",
", ",
"conduction",
" and ",
"radiation",
". If you leave a solid object in a room as you describe the two main methods for heat transfer will be the conduction of heat from the object to the air and radiation.",
"For an object of relati... |
[
"How does heroin work?"
] | [
false
] | [deleted] | [
"Ok so I don't have alot of time to write this reply but I'll try to come back later and elaborate. Heroin is an opiate and works by binding to and \"activating\" opiate receptors found in the nervous system (I think in particular it is the μ receptor subtype). These opiate receptors are G-protein-coupled receptor ... | [
"When you get hurt or run for a long period of time, your body releases endorphines which helps diminish pain and improve mood. When you do heroin, your body release a fuck ton of endorphines."
] | [
"basically when you get hurt your body sends signals to the brain via the spine, sometimes this can release opioids which are released into the spine at the location of the pain and make it harder for the nerve cells detecting the pain to fire, thus 'dulling' the pain. Let me know if you want more details "
] |
[
"When our sun enters the red giant phase in five billion years, terminating all life on earth, is there reason to believe that the human race will still be here?"
] | [
false
] | null | [
"Five billions years is an amount of time incomprehensible to humanity. All of the existence of the hominids that could be called \"human\" has occurred in just ",
" years. That includes every single thing that every single human that has ever lived and died has ever done, and most of that has only been in the ... | [
"Something most people don't know is that our planet is doomed well before our Sun's red giant phase some 5 billion years from now.",
"As the proton-proton fusion reactions continue in the Sun's core, this leaves behind helium \"ash\" in its wake. Helium ash is denser than the surrounding hydrogen and so it tends... | [
"And in 5 billion years that which came from us will have evolved into a completely different and unrecognizable species. We may be their ancestors but they won't even resemble us in the slightest. "
] |
[
"Easy and cheap astronomy/physics experiments?"
] | [
false
] | null | [
"A decent telescope (6-8 inches) can be a lot of fun. You can see neat stuff like Saturn's rings and Jupiter's moons, and also multicoloured double stars, globular clusters, galaxies, etc.",
"You could probably measure the spectrum of a star by focusing it through a pair of binoculars (or a telescope) onto a pris... | [
"A diffraction grating sheet might fit directly between your telescope and your eye, and should work the same. Stars are quite faint, however, I'm not sure how well you'll be able to see the spectral components."
] | [
"I remember Isaac Newton doing this with Venus in The Baroque Cycle; I think you'd just need a big enough telescope.",
"If you spectrized* the light with a prism and lead it into a digital camera the analysis would be pretty easy to do with matlab. Just take a horizontal slize of the image matrix, run rgb2gray on... |
[
"A question about Pavlov's Dog."
] | [
false
] | First, can pavlov's law be used on humans? What if the person is aware of what you're doing? Will it still work? Say I tried to do it to myself, could I? For example, if I listened to the same song every night as I went to sleep, when I heard that song outside of bed, would it make me tired? Just something I was thinking about last night, Thanks. | [
"My psych teacher sat in front of me and said a bunch of random words, and every time he said \"candy\" he sprayed me in the face with a water bottle. I knew exactly what he was doing but when he said \"candy,\" i flinched every time, even when he stopped spraying me."
] | [
"If you get into a routine you will condition yourself, even if you know it's happening. For example getting home and going to the bathroom will make you want to go as soon as you get home, eating at a certain time will make you hungry at around that time, etc.",
"Yes, this works just as well on humans."
] | [
"Your psych teacher is a mad man. And with that said, I'm sad that there aren't more teachers like him."
] |
[
"Food, toothpaste, mouthwash, soda, and everything else tastes weird! What can/is causing this?"
] | [
false
] | null | [
" Good call kanehau. My initial thought was ",
"miracle fruit",
", but the OP didn't menion any dietary changes other than stopping sweets. My mind drifted toward medical problems. Mea culpa. "
] | [
"Oh my!!!! I put a whole jar of pesto in 3 pounds of meatballs! ",
"Someone give this man another tag! "
] | [
"Yeah, pine nuts are one of the main ingredients. Thanks, at least I don't have mouth cancer.."
] |
[
"What would happen if you let a cramp continue cramping?"
] | [
false
] | Assuming you could deal with the pain, what kind of damage could happen to an un-fixed cramp? | [
"I assume you mean a charlie horse type cramp where the muscle spasms largely independent of your control?",
"Assuming that's what you mean, the muscle will gradually relax. I have very tight muscles in my legs and they will regularly become sore just from sitting around. I'm able to stretch my large toe in a par... | [
"He said you would lose circulation and your heart would explode... ಠ_ಠ"
] | [
"What'd that person say?"
] |
[
"Since electrons can only occupy certain quantum states, how are these affected by chemical reactions such as the loss of a proton?"
] | [
false
] | I was just thinking about simple double bond formation in carbon compounds by removing a proton. Does this chemical reaction create an instantaneous quantum shift in the electrons? | [
"Point of clarification - in organic synthesis, it is common to run across \"protonation\" and \"de-protonation\". What's happening is that a hydrogen is being added or removed, for example by changing the pH of a solution containing an organic acid. The question is about the shift in the electron density once a hy... | [
"It depends on where the proton was sitting, but the changes are certainly large enough to be noticed. This is the foundation for pH indicating chromaphores, in fact. Remember that the electronic structure of a molecule is what gives rise to a molecule's absorption spectrum. ",
"If you take a molecule like bro... | [
"I don't understand. Chemical reactions don't remove nucleons like protons, those are nuclear reactions. There are chemical shifts you can see due to the small changes in electron wave functions."
] |
[
"Does genetic testing of embryos impact the child?"
] | [
false
] | So current genetic testing of IVF embryos is to get the egg and sperm together, make a bunch of embryos, wait a few days to see which ones grow and then to pop them open, scrape out a bunch of cells and then send them to the lab. The lab then tests those cells for any abnormalities (aneuploidy, etc) while the embryos get frozen. Once results are back the cleared embryos can be implanted one at a time until one takes. So there has been some research on childhood cancer risk of frozen embryos and that seems to be a bit elevated relative to standard - 1.6-1.7 times. This is still a fairly new process and we don’t know if there are any impacts later in life from freezing, it’s an open question as frozen embryo children hit middle age. Fingers crossed. My question was on the genetic testing side. If you have an embryo and pop it open and remove a bunch of the very first cells, then the remaining cells step up and still deliver a baby. That is established. What impacts might arise from the cell removal process though? Like if you were going to have 100 cells at that point and are now down to 90 or whatever then would that have any impacts later in life? The remaining cells need to divide more I guess. Thoughts? | [
"The cells are not taken from the embryo directly, they are taken from the Trophectoderm which is comprised of extra-embryonic tissue which does not become part of the fetus itself. Cells in the Trophectoderm become part of the support structure for the fetus like the placenta."
] | [
"Depends on the exact procedure. Blastomere biopsies are before that distinction.",
"EDIT: Had to edit my post because both blastomere and blastocyst biopsies happen on day 3 (blastomere in the early part of day 3, blastocyst later in day 3) but my overall point of \"it depends on the exact nature of the test\" i... | [
"Like if you were going to have 100 cells at that point and are now down to 90 or whatever",
"They do it even earlier than that, at like the 8 cell stage when presumably it is so early in embryogenesis that there's no impact. You are right that it is still a relatively new technology but so far there has yet to b... |
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