title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Could quark color confinement limit the accelerated expansion of the universe?"
] | [
false
] | When quarks are pulled apart there is a point where the gluon field "snaps" to create a new quark/antiquark pair, wouldn't the expansion of the universe some day supply enough energy to cause massive creation of mesons, thus slowing expansion down or at least stabilize it's rate? | [
"Here's a similar question from earlier: ",
"http://www.reddit.com/r/askscience/comments/grcna/big_rip_question/"
] | [
"I remember someone showing that this could only happen if the accelerated expansion was more than accelerated (or w < -1 in physics lingo).",
"But suppose that this could happen and you can go around creating quarks. Essentially you change nothing, since most of the mass of the pair comes from the gluon potentia... | [
"this is way over my head.. explain it to me like i'm 5;) "
] |
[
"What's going on the brain of a psychopath? Scientifically, why can't they feel emotions?"
] | [
false
] | null | [
"Psychopaths feel emotions. They do not feel empathy.\n",
"http://en.wikipedia.org/wiki/Psychopathy",
"Psychopathy (/saɪˈkɒpəθi/[1][2]) is a personality disorder characterized primarily by a lack of empathy and remorse, shallow emotions, egocentricity, and deception.",
"That means, just for an example, you s... | [
"The first paragraph of the shallow emotions section says ",
"Psychopaths do not feel emotions as deeply as an average person. Though they are not completely unemotional, their emotions are so shallow that some clinicians have described them as mere \"proto-emotions: primitive responses to immediate needs.\"",
... | [
"From what I read -from The Psychopath Test - they don't have a functioning amygdala. So they basically don't have fear, guilt or remorse. Bob Hare did crazy tests in the 70s where he would tell his test subjects (prisoners- both psychopaths and non) that they were going to get a painful shock at the end of a count... |
[
"Do elevators use regenerative breaking? (reposting)"
] | [
false
] | I've posted this question a few times now and it just seems to disappear from the timeline. It never shows up in the New tab either. =/ Here's hoping it works. During a single ascent and descent the energy expended to raise the elevator from the first floor to somewhere higher is equal to the difference in potential energy at those two positions. Then that same energy can be gained on the descent and stored in a battery similarly to how hybrids do it. Then the net expenditure in energy can be reduced only to the loss due to friction and the conversion between electricity and motion, both of which can be trimmed considerably if I'm not mistaken. So do elevators do this? If not, why not? Edit: Thanks to everyone who answered! | [
"I repair elevators. The elevator is usually setup so the counter weight equals the mass of the elevator plus forty percent of the rated elevator capacity. An elevator generally only draws a decent amount of power while starting and stopping. The power saved by using a regenerative drive is so minimal that you'd n... | [
"Keep in mind that elevators have gigantic counterweights with masses about equal to that of the elevator, so as long as they don't accelerate quickly, they aren't doing as much work as you may think they are. For fun, compare to the ",
"Atwood machine",
"."
] | [
"I think this is the key point. I was talking with the elevator repairman in my building (mostly to make sure I wasn't going to end up trapped in one of them, because how many times have you actually seen an elevator repairman?) and he said something in passing that lead me to believe that the weight limits on elev... |
[
"What causes the feeling of you 'falling' out of your sleep?"
] | [
false
] | null | [
"fast and short answer: the brain confuses your body relaxing with weightlessness, freaks out and tries to deal with falling. "
] | [
"Radiolab did a segment about the hypnic jerk. ",
"http://www.radiolab.org/2010/sep/20/still-hanging/"
] | [
"Radiolab did a segment about the hypnic jerk. ",
"http://www.radiolab.org/2010/sep/20/still-hanging/"
] |
[
"Why are so many common pain relievers also fever reducers?"
] | [
false
] | Acetaminophen, Ibuprofen, and Aspirin seem to be the most common over-the-counter pain relievers, but they also work as fever reducers. Why does fever reduction seem to go hand-in-hand with pain relief? Is it a trait of the drug itself, or does soothing pain and inflammation in the body reduce fever? | [
"But acetaminophen isn't an NSAID, correct? Does it still affect the COX enzymes? It doesn't typically do much for inflammation, AFAIK.",
"P.S. Thank you for digging up the info on the NSAIDs, that does make a lot of sense!"
] | [
"But acetaminophen isn't an NSAID, correct? Does it still affect the COX enzymes? It doesn't typically do much for inflammation, AFAIK.",
"P.S. Thank you for digging up the info on the NSAIDs, that does make a lot of sense!"
] | [
"What do you mean by \"responsible for\" in tour first sentence? "
] |
[
"How do spacecraft like Cassini avoid being ripped to shreds by space dust?"
] | [
false
] | null | [
"There's simply so little of it. A couple of dust impacts over a whole mission, maybe.",
"I'd be interested in seeing what happens to voyager in a billion years, maybe it would run into some occasional bits in interstellar space and become a cloud of dust heading in one direction. More likely it won't run into mu... | [
"When Cassini first flew between the rings and Saturn (couple months ago), they actually turned the spacecraft to use the radio dish as a shield since they didn't really know what to expect. It actually encountered so little dust, that they opted not to use the \"shield\" in later dives."
] | [
"Get out. Now that's cool. I'm glad I asked! It was the rings specifically that made me think of the hazard"
] |
[
"Can your eyeballs freeze?"
] | [
false
] | null | [
"Eyeballs contain two types of liquid",
"If you had a set of eyeballs, detached from the human or animal body (for example cow eyeballs used for dissection purposes) they would freeze at 32 degrees F or 0 degrees Celsius- or perhaps a few degrees below due to the tissues surrounding the eye.",
"Eyeballs attache... | [
"Thank you as well."
] | [
"Can you elaborate please."
] |
[
"Labeling a Protein with GFP?"
] | [
false
] | [deleted] | [
"Yeah, to echo what rupert1920 said, I'm gonna have to recommend finding a lab that does it and having someone teach you. I was in the unfortunate position once of being the guy in a genetics lab who had to learn some biochemical techniques that no one in my lab was familiar with, and the ",
" way I even got clos... | [
"I know this is unhelpful, but in a pure Material lab this is not gonna happen. Aside from the protocol itself (which isn't terribly complicated but can be temperamental), there's just so much ",
" I don't think you have. I recommend outsourcing to another lab or company.",
"Also, what are you mapping exactly? ... | [
"Thank you. "
] |
[
"Provided you didn't burn, would you float or sink in molten lava?"
] | [
false
] | null | [
"You would float. Lava is about 3 times as dense as water, while people are approximately as dense as water. Thus, just as wood floats in water (wood is less dense than water, so it floats), a person would float in molten lava.",
"You can a whole discussion of this ",
"here",
"."
] | [
"But, the burning is an important thing to consider. Even if a liquid is denser than you, you won't be able to stand in it, you'll end up horizontal and how much you float depends on your buoyancy. You're made mostly of water, and lots of stuff that releases other gases, like co2, when they burn. Now, the part of y... | [
"That video is incredible. Do you know if the turbulence in the lava is from gasses leaving the trash box and rapidly expanding?"
] |
[
"Is it possible that a mountain taller than the everest existed in Pangaea or even before?"
] | [
false
] | And why? | [
"The tallest mountain of all time is probably around the height of Mount Everest because mountains hit something called the ",
"isostatic limit",
" whereby they cause the earth's crust to compress from sheer mass. Olympus Mons is another mountain that reaches the isostatic limit, but is significantly higher bec... | [
"Probably a lost cause given the number of upvotes the top comment has received, but I feel the need to point out that while ",
"it",
" is correct in the sense that Everest probably represents about the highest mountain we'd get on Earth, the explanation provided along with that is a gross (and largely wrong) o... | [
"Thank you for the great and clear answer!"
] |
[
"Has science determined the most effective way to study while in school?"
] | [
false
] | I know there's a lot of dimensions to the act of studying, i.e duration, intensity, specific study strategy ( e.g outlining, making note cards, etc). I've heard people talk about the Pareto method as the best duration and my teachers have always brought up things like outlining, etc. Is there any one combination that is the best across subjects? Conversely, is there any method that works best when studying mathematics? | [
"Not sure if this is what you had in mind, but here are a few thoughts. Also, this isn't my main area of study, so if someone has new thoughts to add, please do.",
"Spacing is better for retention than blocked studying. Adaptive spacing is even better. Most people do this naturally when they have something like f... | [
"In the original paper, I believe they simply made the font of the study material more difficult to read (small or blurry). I think the idea was that this required greater effort / concentration to retrieve the material and that this benefited encoding. I'd look for papers by Bjork or Oppenheimer; both are mentione... | [
"Thank you answering my question. Can you talk a little more about what it means to make something \"effortful?\""
] |
[
"When I lift something is my brain continously sending signals to the muscle to contract or does it send one signal to contract and one to relax?"
] | [
false
] | null | [
"Continuous signal for continuous muscle work. The signal stops when you will your muscle to relax. The signal itself is in action potentials per second. The neurons firing action potentials on muscle cells telling them to contract can fire more rapidly or slowly, leading to different contractions."
] | [
"There are more AP/s overall lifting something heavy but not for each muscle fiber as each muscle fiber works in an all or nothing fashion. As in if you're using only your bicep to lift something then as soon as you begin lifting it your body will tell a certain amount of muscle fibers, a motor unit, in your bicep ... | [
"Interesting, and does the AP/s change depending on how much strain there is? Ie is it more AP/s to lift something heavy than something light?"
] |
[
"Why do planes fly?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"To check for previous similar posts, please use the subreddit search on the right, or Google site:reddit.com",
"/r/askscience",
" ",
"Also consider looking at ",
"our FAQ",
... | [
"https://www.reddit.com/r/askscience/comments/7nlsuf/which_explanation_for_aerodynamic_lift_is_correct/"
] | [
"https://www.reddit.com/r/askscience/comments/7nlsuf/which_explanation_for_aerodynamic_lift_is_correct/"
] |
[
"What's the science of drinking while pregnant? There is a lot of conflicting information out there."
] | [
false
] | I am not a scientist (which is probably apparent by the way I am asking my question). Everything I can seem to find about drinking during pregnancy simply says "We don't really know what's going on, so how about you don't drink, eh?" I am not really satisfied with this answer and have a hard time believing there is not more, uh, science that could be used to explain the matter. I've read that a woman should not drink from the second of conception. But, it seems that most people will end up drinking some time after conception because it's impossible to know that one is pregnant until several weeks into a pregnancy. I've also read that a baby does not begin receiving nutrition from the mother's bloodstream until the fourth or fifth week after conception. So, how would earlier pregnancy drinking even matter? Or, is it just a matter of professionals being worried about the woman's nutrition while carrying the fetus (a concern that if she is consuming alcohol, she may not be consuming enough nutritious food)? Additionally, wouldn't any alcohol that is consumed get filtered out before it reaches the fetus? I have a feeling a lot of the warnings out there about drinking during pregnancy are advising women to be overly cautious and paranoid. This has been asked here before, but there was no satisfying answer given or reply beyond "It's just easier to tell women to not drink at all, rather than to drink in moderation, because you can't trust those who tend to binge drink to know the difference." | [
"There's a good amount of data out there on the topic (though of course it is hard to do a real randomized control trial of any sort). Unfortunately, I have yet to see a definitive study that clearly answers all of the questions we have on the topic (partly due to the ethical difficulties in this field).",
"This... | [
"Alcohol can absolutely cross the placenta and enter the fetal blood stream. This can cause fetal alcohol syndrome, as alcohol acts as a teratogen after crossing the fetal blood/brain barrier, and can produce substantial central nervous system defects and brain abnormalities. The exact mechanisms by which this happ... | [
"r/AskScience",
"As always, please refrain from anecdotes, speculation, jokes, and off topic discussion. ",
"Thanks!"
] |
[
"Why do we use mouse fibroblasts and bovine serume to culture embryonic stem cells?"
] | [
false
] | I was just reading up on some stuff on the NIH website about stem cells, and they had that bit about their culturing. I don't understand why they need the fibroblast cells (for structure or support?) or the bovine serum. Just general curiosity. If anyone has links or answers that would be great Thanks! | [
"The fibroblast cells are usually mouse embryonic friboblasts. These cells release several key factors, including leukemia inhibitory factor, that promote the proliferation of human ESCs. In addition, fetal bovine serum contains many factors that support ESC self-renewal and proliferation. ",
"Over the years ther... | [
"Ah thanks, I got my information from this website, ",
"http://stemcells.nih.gov/info/2006report/2006Chapter1.htm",
", and they never really told me why they used fibroblast cells for culturing. Also, that article stated that LIF, in the presence of serum, was not sufficient to promote self-renewal of human ES ... | [
"There are several cell lines now that grow well without the fibroblast feeder layer or serum.",
"This. We just started doing this with our human ESCs. So far the morphological differences are minor to none, but we have noticed they differentiate slower. But we definitely want to move off of using the MEFs (mouse... |
[
"When is the next time humans will evolve?"
] | [
false
] | null | [
"Evolution is a continuous process."
] | [
"then everyone will be differently evolved, but i dont see it"
] | [
"Everyone looks different and we all have inherited traits from our parents. Perhaps you mean something else by \"evolution\" than how the word is typically used."
] |
[
"Where does body heat come from?"
] | [
false
] | I understand that blood is warm and the cardiovascular system distributes blood/oxygen/heat throughout the body, but how does the blood get hot in the first place? | [
"The catabolism of sugar, fat, and protein with oxygen to make ATP (basically transferring energy from chemical bonds to a different type of bond that is used by the body's cells as fuel) is not 100% efficient. This produces heat and thus warms our blood. The blood circulates to your core and warms your body. ",
... | [
"Have you ever stethoscoped yourself? There's a lot of weird noises that your brain ignores"
] | [
"That is correct, but the amount of acoustic energy is negligible for humans and engines. When screaming you lose far more energy from exhaling warm air than from producing sound waves. "
] |
[
"Is there any genetic or other benefit for tree leaves to get so brightly colored in the fall?"
] | [
false
] | I know part of it is just the conversion of the remaining sugars and chlorophyll loss. But it seams to me the trees must get something out of it? Bright colors in nature are usually for mating or spreading of seeds. Neither one appears to be the case with dead leaves. I'm wondering if perhaps the bright colored leaves on the forest floor, reflect more light than dull brown leaves, and therefore help keep the branches/trunks warmer and chemical processes going in the day time? Edit: Found this, "The evolutionary theorist W.D. Hamilton and Samuel P. Brown of the University of Montpelier speculated in a recent paper that the healthiest trees might put on the flashiest fall displays of (anthocyanin) red leaves. They further speculated that this leaf signal might give fall-feeding insects, such as aphids, a warning to avoid trees that are healthy and have the best defenses. This is an intriguing possibility for yet another role of anthocyanin in tree protection." near the end of this paper, | [
"The reflected light of the dead green leaves on the forest floor cannot be used by the surrounding living trees whose leaves are the same colour. The green colour that we see is the wavelength of light that the chlorophyll(and supplementary light-absorbing molecules) cannot use. The white light they receive has al... | [
"Yes, that part is fairly obvious about the green light, But I was asking if there was any benefit of them changing to the bright colors. I would imagine its a teeny one if at all. "
] | [
"There is no advantage to the colour itself. They are brightly coloured as they are because the tree is producing more chlorophyll than xantophyll, carotene and other pigments that typically reflect other colours. Chlorophylls absorb more energy than other pigments, so the plant produces much more of it than it doe... |
[
"How strong does a drink have to be to dehydrate you?"
] | [
false
] | Alcohol inhibits ADH secretion which leads to the old "one drink in two drinks out." Do drinks below a certain percent alcohol by volume hydrate you while drinks over that point dehydrate you? | [
"This is not an actual answer to the question. Please read the ",
"r/askscience",
" posting guidelines."
] | [
"In the past, people would brew beer/wine at the same strength that we do now, but they would water it down significantly before consumption (3-4 parts water to one part beer). A weakly alcoholic drink is enough to kill most pesky water-bourne pathogens. This is why children in medieval times were able to consume b... | [
"Question: Do you have a source for your 2 in 1 out info? I've never been able to find one. "
] |
[
"Do the languages we speak affect how we perceive (not reproduce) sounds?"
] | [
false
] | EDIT: I appreciate the responses so far, thank you! Are there experiments where the same sound (a linguistic sound) was heard by two people with different native languages? | [
"Yes, absolutely. We build a phonological model in our head that is trained to recognize a subset of all possible phonetic segments. This allows us to error-correct in our native language more easily.",
"For instance, in my dialect of English, I have the vowel /u/. This is a high back rounded vowel, the one in th... | [
"also not sure why this is flaired neuroscience when this is in the clear purview of linguistics.",
"Well he does speak about perception which would go under neuroscience.",
"And also in that sense the answer is absolutely. We actually hear different sounds differently depending on our language proficiency. Two... | [
"There's a higher rate of perfect pitch among native speakers of tonal language like Mandarin, Cantonese, and Korean. In English for example we use pitch to adjust inflection, for instance when asking a question you'll raise the pitch of your voice at the end of the sentence. In tonal languages pitch inflection is ... |
[
"Do dogs actually have no concept of time? do any animals?"
] | [
false
] | null | [
"I don't believe your premise is correct. There is an obvious difference in the way my dogs react after not seeing me for a week versus a few hours. ",
"I recall a documentary I saw that analyzed a dog's ability to seemingly know when it's owner was home before the owner was within eyesight of the front door. ",
... | [
"Thank you. I changed the wording of the question"
] | [
"There's no way of definitively knowing how other animals perceive time, and research on how dogs perceive time is rather limited.",
"There's a good article at discovery here:",
"http://animal.discovery.com/pets/dogs-perceive-time.htm",
"Also note that things like circadian rhythms, knowledge of daily feeding... |
[
"Just like in supersonic motion, the object that creates the sound can move faster than the waves it produces, is it possible for the E-field or B-field that make up light to move faster than the light?"
] | [
false
] | null | [
"The light (i.e., the electromagnetic wave) ",
" the E- and B-fields. So the answer to your question is trivially \"no\"; something cannot travel faster than itself.",
"But perhaps you mean to ask whether a source of light can travel faster than the speed of that light ",
". So, for instance, can an underwate... | [
"Yes. ",
"Sort of.",
" The mechanisms for the production of sound and light waves are different, so obviously the analogy should not be taken too literally. "
] | [
"So is Cherenkov Radiation a sort of 'superluminal flash', analogous to supersonic booms? "
] |
[
"How many calories do you lose when donating blood?"
] | [
false
] | null | [
"most people die if they donate too much\nprobably"
] | [
"Anything over a pint every 56 days. Not to mention it's dangerous to do much exercise for a number of hours after. It'd be an extremely dangerous or inefficient way to lose weight. Just watch your caloric intake and exercise regularly."
] | [
"This guy calculates it at about 450 calories.",
" He took into account blood glucose, sugar, fat, and red blood cells."
] |
[
"What will be the effects to Europe/the rest of the World if the Bardarbunga volcano erupts?"
] | [
false
] | Or should it be a matter of 'when', not 'if'. And if I may add - could this eruption trigger the other Icelandic volcanoes on the same 'chain'? | [
"This depends on a number of things, but chiefly a) what kind of magma is down there and b) what the weather patterns are like at the time.",
"Bárðarbunga is particularly well known for its lava flows, which generally require low gas contents in the magma. That means the eruptions will generally be effusive - so ... | [
"Possibly, but it depends on the plumbing system and where each feeds off from. "
] | [
"Thank you for replying! I appreciate the explanations. "
] |
[
"Is the vacuum of outer space fundamentally the same as the empty space between particles like electrons and proton? Or are they different somehow?"
] | [
false
] | To be clear I'm not suggesting that planets and stars are equivalent to protons and elections. I'm just curious about the empty space. I've heard that the vacuum of space is actually supposed to be an energetic place because of virtual particles, how does this compare to the mostly empty space of an atom? | [
"An atom is not mostly empty space. This is a common misconception. The electrons, protons, and neutrons that make up an atom are not little solid balls separated by vast expanses of empty space. They are quantum objects that act somewhat like waves and somewhat like particles. In an atom, the electrons act mostly ... | [
"Here's the problem: in quantum mechanics, there's a clear division between what you see and what is actually there.",
"The truth is that there is a wavefunction, which governs the probability of what you see at any given time. Imagine the universe as a giant spinner, and every time you take a measurement and mak... | [
"I've heard this wave/particle explanation before and I know it has something to do with observance, but I've always had difficulty trying to visualize what a subatomic particle would actually LOOK like, say, if you magnified it to size of your palm. Is trying to visualize it just an exercise in futility?"
] |
[
"When was there a 'cosmic visible light' background?"
] | [
false
] | Since the expansion of space causes the wavelength of cosmic microwave background to lengthen, presumably it would have covered other parts of the electromagnetic spectrum in which wavelengths are shorter. We also seem to have a pretty good idea of the rate (and rate of acceleration) at which space expands. So at what point in the history of the universe could I look around me and see blue everywhere? Is there an equation for this? I'm not afraid of math. | [
"Shortly after the Recombination era - the era from which cosmic background radiation originates - the cmb was bright orange. ",
"To understand what exactly happened, let's backtrack a bit.\nUntil 380 000 years after the big bang, the universe was too hot to form neutral atoms. Electrons and protons whizzed throu... | [
"By the time planets (solid objects you could stand on) had formed, the background radiation had already expanded and cooled below the visible range of the electromagnetic spectrum. Space was already \"dark\" before the first planets formed. "
] | [
"Just to make sure I'm following. There was no point in time where there was a solid surface to stand on and the night sky did not appear black with spots in it correct? "
] |
[
"Does milk spoil inside of female mammals?"
] | [
false
] | If a female, let's say cow, isn't milked for a while, does her milk spoil in the same way milk spoils if left out in a similarly temperatured container? | [
"It’s possible. Mastitis is an infection of the breast or udder, due to pathogenic bacteria gaining access to the breast milk. However, under normal conditions the environment that the milk is in is highly controlled, sterile condition. "
] | [
"This is just nonsense, and dangerous misinformation. Natural milk absolutely spoils and raw milk is far more hazardous to health, it has a higher bacterial content and spoils quicker. There is more to producing yoghurt than just leaving milk out to spoil, as anyone who has left out milk (yes even 'natural' milk) w... | [
"This is just nonsense, and dangerous misinformation. Natural milk absolutely spoils and raw milk is far more hazardous to health, it has a higher bacterial content and spoils quicker. There is more to producing yoghurt than just leaving milk out to spoil, as anyone who has left out milk (yes even 'natural' milk) w... |
[
"If I was in intergalactic space such that a nearby galaxy filled up my entire field of view, would I be able to see it clearly? Or would it still be as dim as the milky way is in the sky here on earth?"
] | [
false
] | [deleted] | [
" This is why you need about the same darkness of sky to see both the Andromeda Galaxy as well as the Milky Way.",
"As you approach an object, the brightness of an object increases as the distance squared, but the total amount of area in your field of view will ",
" increases as the distance squared. The result... | [
"This is one of those extremely disappointing facts about reality. Even if we get magic spaceships and zip around nebulae and dart from galaxy to galaxy without a care in the world, to our eyes, it would be mostly pitchblack, with faint smudges of gray. ",
"Those romantic images of space stations suspended in pin... | [
"You know whats truly amazing? You don't even need to be a professional astronomer to be able to get to see the beautiful colors out there. ",
"I've just started to get into astrophotography, so I'm not that good... But for somewhere between $500 to $3000 and a bit of patience you can see the beauty of the univ... |
[
"How does WiFi go through walls?"
] | [
false
] | So to my understanding, WiFi is Bluetooth; which is infrared light. Infrared light waves are less intense then electromagnetic light (the visible light). So how can my wireless router a few walls away from my computer send light information to it if I can't see it Line Of Sight? Does it act as a wave ? Does it go through the wall? Do the atoms that make up the wall, hold and then release the light wave? And if infrared red light can travel through or around walls why can't we see around or though walls? TL;DR How does WiFi travel where normal light doesn't? | [
"WiFi isn't bluetooth and neither is infrared light. Your basic WiFi is ",
"radio waves",
" in the 2.4, 3.6 and 5 GHz frequency bands, ",
"from standards definition IEEE 802.11",
". ",
"Bluetooth uses ",
"short wavelength radio transmissions in the ISM band from 2400-2480 MHz",
". ",
"So both use r... | [
"First: Intensity and Frequency are two independent properties of light. Infrared is lower frequency than visible light, but can be both more or less intense (think power).",
"Second: Light of all frequencies penetrate most materials, but the attenuation experienced is generally inversely related to frequency. Th... | [
"Radio waves are also lower in frequency than the visible spectrum... so the same way that radio waves do it :D"
] |
[
"When your body responds to changes in temperature by doing things like sweating or shivering, is it our minds’ perception of the temperature that causes this or does the temperature somehow directly do this?"
] | [
false
] | Since that was probably a confusing title, here’s an example: if you were sitting in the snow and it was below freezing out, yet somehow in your mind you were completely convinced that it was warm out and that you weren’t cold at all, despite your internal temperature dropping, would you still start shivering? | [
"It's all regulated by your brain, but it's not a conscious thing. As an interesting example of this the reason you feel chills when you have a fever is because there are chemicals being released in your body in response to an infection which increases your body's \"thermostat\" to a higher level. In the time betwe... | [
"Unrelated but the dudes who walk on coals aren't actually nearly as impressive as they first appear. By stepping quickly you don't give the coals much of a chance to actually transfer the heat into your feet and there's water on the ground before and after, so their first few steps are just producing steam and the... | [
"Unrelated but the dudes who walk on coals aren't actually nearly as impressive as they first appear. By stepping quickly you don't give the coals much of a chance to actually transfer the heat into your feet and there's water on the ground before and after, so their first few steps are just producing steam and the... |
[
"Is there always a set number of atoms in the universe?"
] | [
false
] | I mean like is/will there be/was there always the same amount? Ofcourse we won't know the amount if so I just really need to know this. Always bothered me since I was young. | [
"No. Nuclear fusion and fission will change that number."
] | [
"Mass doesn't. It changes in nuclear processes.",
"Locally, energy is constant, but not cosmologically."
] | [
"True.",
"It should be said though that the total mass/energy of the universe remains constant (remembering that energy and mass are equivalent with E=MC"
] |
[
"How factually correct is Haldeman's depiction of time dilation in the Forever War?"
] | [
false
] | I was recently finished The Forever War by Joe Haldeman and I was curious as to how accurate his representation of relativity and the flow of time is throughout the novel. | [
"Can you describe it for people who haven't read it?"
] | [
"Yeah, no problem. This if from the first section of the novel. Essentially humanity is engaged in a war that branches out across the galaxy. Humanity has near light speed travel technology and their ships can reach speeds up up to ninety percent the speed of light and uses this technology to travel between Collaps... | [
"I happens to be in the middle of reading it right now. It's not mathematically correct. At 0.9c, it would only slow down by a factor about 2.3, so 2 years would be 4.6 years, not 25.",
"Edit: to have 25 years pass on earth, it needed to be traveling at about 0.9968c."
] |
[
"Can anyone give a comprehensive explanation of sunglass lenses?"
] | [
false
] | Reading up on sunglasses is confusing as heck, especially for anyone hoping to save a bit of money. There's a lot of science here, and I'm having a lot of trouble finding a proper comprehensive rundown of everything that's involved, and what it all winds up meaning for consumers. First you need to decide wether you want CR-39, Polycarbonate, Trivex, or Glass lenses. Does it even matter? Well, it might. If you're buying cheap and the glasses don't come with much (or any) reliable info, at least you'll know they're relatively UV resistant if they're Polycarbonate or Trivex, because that's a natural quality of those two solutions. Even still, they're not naturally UV400 compliant, so additional treatment/layers/coatings are needed to achieve that. Speaking of which, what the heck is UV400 and how does it differ from the other standards? Which is best? How much does it matter if you get a pair of sunglasses that doesn't explicitly comply. Are there various levels of compliance? What about how UV and Polarization are even achieved? There are different methods, but what are they, and which are the most effective/desirable? Again, how much does it really matter? I know if it's a coating that easily wears off, that's bad, but how common is that? I've read that some Polarization is incorporated right into the lens itself, some are layered into the middle of the lense between sheets of glass, and some are just a film that's applied to the outside. What are the differences? There's no Polarization standard as far as I know, so how do you know what you're getting? Which is best? I've heard lens clarity and uniformity can be a big deal, but aren't always easily perceptible. I've heard ones with lower clarity/uniformity can stress eyes and eventually cause notable eye problems. Is that accurate? How does one identify good lenses in this regard? I'm sure I'm missing quite a bit, but I hope someone who knows more about this topic can give a lot more information. Thanks! | [
"Whatever you get, you ",
" want polarized lenses. Sunlight reflecting off of surfaces tends to be strongly polarized in the horizontal plane while polarized lenses are polarized in the vertical plane (fun experiment--try rotating a polarized lens held between you and any horizontal surface with a light reflectin... | [
"Second that, polarized lenses is a very good feature. Good for drivibg and also very good anywhere near water. I use my polarized sunglasses on boat vacation, It helps a lot with eyestrain from reflections and makes it easier to see reefs right beneath the surface."
] | [
"Even more fun - put the first two sunglasses at right angles to each other so they are blocking light, then put a ",
" pair between them at 45°. Light gets through again!"
] |
[
"Why/how does resetting a router fix so many connection issues?"
] | [
false
] | null | [
"Longtime computer tech here. ",
"This is a very wide open question! The rebooting of the router can resolve DNS resolution issues on both the WAN side and the LAN side. Your modem may require authentication between the router and the modem and that has failed, thus rebooting the router allows the modem to res... | [
"On a very simplified level, a router is a ",
"finite state machine",
" - a software construct that is designed to operate in a fixed number of states and can transition between these states based on predefined rules.",
"For example, the states might be:",
"And the rules might be something like:",
"This t... | [
"To add another one, most cheap residential routers have a very limited supply of RAM. Depending on how the router is configured, many open connections could cause the router to refuse new connections, thus leading it to effectively shit the bed. I used to see this with my old router all the time whenever I had a... |
[
"If I write a program that generates every possible version of a 50KB jpeg file, do I then have a picture of everything that exists in the universe?"
] | [
false
] | This kept me awake tonight: So if I generate every possible jpeg image I should have a picture of everything that exists, has existed or will exist in the future. And also pictures of everything that doesn't exist. | [
"The amount of combinations how you can fill 50KB is limited.",
"It's finite, yeah, but it is BIG. I just calculated an approximation and tried to post it, but reddit literally won't let me make a post long enough to contain the number. In fact to post the entire number of 50KB binary files in decimal I would nee... | [
"I remember being 12 years old when I just figured out how to render sprites on my ZX Spectrum. I had the exact same thought as the OP and actually wrote a program to generate all possible sprites of 16x16 pixels. I thought I was going to sit back and watch every porn picture imaginable unfold before my eyes.",
"... | [
"To go further, the absolute shortest length of time which makes sense in physics is called the Planck Time.",
"This doesn't affect the correctness of your answer, but I thought you might like to know that the above statement isn't quite true. The Planck length (and accordingly, the Planck time, which is a measu... |
[
"If the energy:mass ratio changed, would gravity change?"
] | [
false
] | Is the amount of energy-stuff that matter is equal at all relevant to the amount of gravity it pulls off? | [
"Are you asking about the equivalence principle?"
] | [
"Yes, it would change. A good example is the expansion history of the universe, as the expansion rate is governed by gravity. In the early times, the universe was filled with particles that moved nearly at the speed of light, so most of their energy was kinetic. As the universe expands, this particle soup cools dow... | [
"The transition between the two is smooth (but reasonably quick, cosmologically thinking)"
] |
[
"How is a species declared extinct?"
] | [
false
] | Pretty much the title. Who declares it officially and how is it determined with any certainty that's it's gone and not just difficult to find, especially smaller species in large ranges? | [
"It used to be easy. The convention was that if a species hadn't been sighted in 50 years it was considered extinct, but as of the 90's, according to the International Union for Conservation of Nature:",
"\"A taxon is Extinct when there is no reasonable doubt that the last individual has died. A taxon is presumed... | [
"That makes sense, thank you"
] | [
"How does this apply to species which only exist in captivity e.g. axolotls? Are they considered extinct?"
] |
[
"Why did physicians historically administer vaccines into patients buttocks as opposed to the Arms/thighs?"
] | [
false
] | null | [
"Are you sure you mean vaccines and not antibiotics? Many vaccines are delivered to the arm/thigh, including mmr and smallpox.",
"More fat/muscle to hold the shot. Penicillin is administered to the buttocks, and it's a large injection. Add in the fact that it's often fresh from the cooler so it feels like peanut ... | [
"There's a maximum injection volume depending on the intramuscular injection site, i.e. Deltoid 0.5-2 mL vs. Dorsogluteal 4 mL. This ",
"article",
" touches on the rationale/history a bit."
] | [
"Add to that higher vascularization. A muscle as big as the gluteus maximus has way more blood going through it compared to a small muscle such as the deltoids."
] |
[
"Why do we hate waiting so much? What is the factor which separates waiting from resting and relaxing??"
] | [
false
] | null | [
"Waiting combines two unpleasant things: frustrated (blocked) progress and loss of control. The frustration-aggression hypothesis has good support, though I don't know as much about scientific support for negative reactions to loss of control."
] | [
"The frustration-aggression hypothesis has good support",
"This is a theory of aggression, not of frustration. Frustration alone is a negative reaction to waiting (via goal obstruction).",
"Edit: To be clear, by invoking the frustration-aggression hypothesis, sleepbot is suggesting that waiting leads us to aggr... | [
"Dude this is why I want to be a psychologist. It's so interesting learning about what fuels human behavior."
] |
[
"Realistically, not like in movies, how much force does it take to knock someone out?"
] | [
false
] | [deleted] | [
"Knock outs are less about absolute force from the punch and more about the forces acting on different parts of the brain. Specifically, a strike that causes the head to twist either down up or side to side can place sufficient stress on the brain stem leading to loss of consciousness. Not surprisingly, variables a... | [
"It is certainly possible"
] | [
"As an aside, the way people are knocked out in movies where they lose consciousness for several minutes (or however long the plot requires) is very, very unrealistic. If someone is out for more than a few seconds it means they have a very serious, possibly life threatening injury and will show very obvious symptom... |
[
"If the moon had seas, how would the tidal forces compare to Earth seas?"
] | [
false
] | Would there be tides at all? Would they be stronger, weaker, act any differently etc? | [
"The moon is tidally locked to earth (the same side is always facing us) so ignoring the sun and the moon's elliptical orbit and axial wobble, there would be no tides at all.",
"In reality the solar tides are still important, so the moon would still have tides with a period of 14.75 (earth) days, half the ",
"s... | [
"What are you even saying?",
"That was a planet revolving around a black hole.",
"Ok. But that has nothing to do with what I said. I mentioned that there were at least some shallow areas on the planet (in response to the 'deep global ocean' line)",
"We revolve around the sun",
"I won't argue with that, but ... | [
"That tidal wave in Interstellar is artistic license, a planet with a deep global ocean wouldn't have noticeable tides.",
"This doesn't change your point, but the water is actually quite shallow, at least in that area. ",
"Still"
] |
[
"Why is homebrew considered safe to drink, but distillates from said homebrew considered unsafe due to methanol?"
] | [
false
] | Or rather why do people claim this? shouldnt there be a similar quantity of methanol predistillation as post? does methanol interact with the body differently at different saturations? it just seems odd that drinking 4 beers is safe but 2 shots from the same product minus a bit of h2o is methanol poisoning blindness country. is there any truth to this? tossing the heads from the start of the run isnt a bad idea, because it'll make the hangover less intense, but is it really as dangerous as people say? | [
"Be very careful here!",
"A still is a device that is designed to separate ethanol and water. Is takes advantage of the fact that ethanol has a lower boiling temperature than water. ",
"The danger is that methanol has a lower boiling point than ethanol. So the same process that separates the ethanol from the wa... | [
"I'm not sure how much of this is from prohibition-era stills that used industrial methylated spirits, and if it's even really a concern any more. There are a few things to consider:",
"Methanol has an LD50 of 5g/kg I think, but it's really only present in your product at around 3ppm, which is about 0.003g/kg. So... | [
"Unless there is methanol present in the homebrew, there will be none in the distillate. Wine will have more methanol, a sugar wash will have almost none. Besides that, a typical distillation goes through three stages:",
"1) foreshots & heads collection. Since methanol boils at a lower temperature than ethanol, t... |
[
"Is there a Doppler effect for quantum mechanical wave functions?"
] | [
false
] | Essentially they are also linear waves, right? | [
"Yeah. If an object is emitting particles with the same energy in its rest frame then (as energy and frequency of the wave are basically the same thing) as it moves towards you, you will see them blue-shifted, and as it moves away they will be red-shifted. In this case it's basically just velocity addition, except ... | [
"To an outside observer the box will appear shorter, so the wavelengths of the wavefunctions will also appear shorter."
] | [
"What about a particle in a box, where the boundaries move at a certain speed ? "
] |
[
"Does the sun make a noise?"
] | [
false
] | After looking at amazing photos of the sun, I wondered if there was any sound coming from the sun. I understand that when I hear a campfire for instance, I'm hearing the sound of air and wood being consumed by the fire. I know in space no one can hear you scream but can you hear our local giant furnace roar? | [
"Sound the way we hear it on Earth is impossible in space since you need some kind of medium for sound waves to travel through. However, the sun, like everything else in the Universe, emits radio waves. We can intercept those radio waves and turn them into sound, just like when you turn on the radio in your car. ",... | [
"Fun fact: if you could hear through space as you can through air, you could indeed hear the sun, and it would so loud it would be the ",
". To see this, note that sound intensity decreases by the inverse square of the distance, same as apparent size does; so the sound the sun makes would be essentially equivalen... | [
"RAAAAAAAAAAAAAAAAAAAAAAAAWR"
] |
[
"Does blending fruits and vegetables in a high speed blender destroy a lot nutrients?"
] | [
false
] | So I have gotten into the green smoothie craze and purchased a vitamix blender a couple weeks ago. Unless I'm eating out, nearly all my fruit and vegetable consumption comes from the random fruits and vegetables that are thrown in my blender. My consumption of fruits and vegetables have increased a lot due to the speed and convenience of just blending everything together. I'm pretty sure you lose something when your turn whole fruits and vegetables into liquefied mush. Just wonder how much and what you lose in that process. | [
"As long as you're consuming everything that went into the blender, you're getting all of the nutrients. Physical forces can disrupt cells and denature some proteins (it's how meringues are formed, for example) but they really can't destroy nutrients; the molecules are simply too small.",
"All bets are off if you... | [
"Denatured proteins are still perfectly viable sources of nutrition."
] | [
"Browning is the action of polyphenoloxidase enzymes on, as you might expect, polyphenols. Some polyphenolic compounds have health benefits, but they also tend to be in fruits without high levels of polyphenoloxidase and the you can easily prevent the action of polyphenoloxidase by lowering the pH. So if you're mix... |
[
"Why does grafting apple trees result in an edible apple?"
] | [
false
] | My understanding of apples and apple trees is lacking.... If an apple tree is left alone to grow naturally it will produce crabapples, correct? So who figured out that connecting the root stock of one tree to the shaft of another will produce flowers that when pollinated yield an edible apple? I would have never thought to do something like this in a million years if someone else hadnt first figured it out. So, what is happening within a grafted tree (on the chemicaly/biological level) that changes the edibility of an apple? | [
"If an apple tree is left alone to grow naturally it will produce crabapples, correct?",
"No. A macintosh tree will produce macintosh apples without a graft. A Mac might be grafted to a hardy root stuck to improve survival in harsh conditions, or it might be grafted onto a dwarf rootstock to force it to be smalle... | [
"Do you know if they breed true, or if they just have good enough root systems to be made from cuttings?"
] | [
"When a tree is grafted you basically end up with a clone of the original tree growing off of the root stock you put it on. ",
"You take a piece of a type of apple tree that makes good apples and you put it on a type that makes better roots.",
"If you plant the seeds from most apples you will not get something ... |
[
"Can the human body have too much blood?"
] | [
false
] | null | [
"In addition to polycythaemia, which is mentioned above, you can also be given too much blood! If you give too much blood [product] via transfusion to someone they can get Transfusion Associated Circulatory Overload (TACO). "
] | [
"In the case of the genetic mutation (Polycythemia vera), blood letting is a correct course of action, iron supplementation is a grave error though. The whole point of blood letting is to deplete the body's iron stores to stop it from producing red blood cells. ",
"Please don't try to explain things that you do n... | [
"In the case of the genetic mutation (Polycythemia vera), blood letting is a correct course of action, iron supplementation is a grave error though. The whole point of blood letting is to deplete the body's iron stores to stop it from producing red blood cells. ",
"Please don't try to explain things that you do n... |
[
"Is looking at a TV or computer screen in the dark worse for your eyes than in a well lit room?"
] | [
false
] | [deleted] | [
"It only causes short-term issues, nothing permanent.",
"Lightness/darkness changes (when as minimal as turning the lights on) only cause pupil dilation, not retina damage. "
] | [
"I think there is also concern that in a dark room the pupils will dilate. A small bright patch in the dark will still result in a dark environment (on average), so the pupils remain dilated. In this case, the portions of the retina exposed to the TV light will be getting more light than normal. Is this a problem?"... | [
"It just causes short term eye strain which can be pretty severe in some cases, it's a good idea to have the wall behind the screen at a similar brightness as the monitor is when displaying white",
"Most screens come 2-5 times too bright for the average room, so most need to be turned down to around 20-30% bright... |
[
"How do scientists know the size of the universe?"
] | [
false
] | null | [
"For reasons I don't fully understand",
"Here, I'll attempt to clear it up. You are correct, the guy you replied to is wrong.",
"Space can expand faster than light. We can measure how fast space is expanding, and that's called the Hubble constant, which is 70 km/s/Mparsec, but it's always changing",
"On phone... | [
"When scientist talk about the size of the universe, what they mean is the size of the observable universe...\nsince the universe is 13.47 billion years old and light has a maximum speed, the speed of light, the size of the observable universe is c*t (in each direction)",
"Concerning the size of the \"whole\" uni... | [
"the size of the observable universe is c*t",
"For reasons I don't fully understand, this is wrong, it's much bigger.\n",
"More info",
"We can't really ",
" anything about what's beyond the observable universe.\nIt could be infinite, it could be about an inch larger than what we can see.\nUnder fairly reaso... |
[
"Discussion: Kurzgesagt's newest YouTube video on the Information Paradox!"
] | [
false
] | Hi everyone! Today on AskScience we're going to learn about the information paradox and why black holes could delete the Universe, with the help of Kurzgesagt's . Check it out and come ask your questions! | [
"Trillions of years doesn't do it justice. A supermassive black hole with 10",
" solar masses would take ",
"about 10",
" years to evaporate",
". We don't really know how the universe will evolve on such long timescales (we don't even know if protons are stable on these timescales, for example), but it cert... | [
"I saw this video earlier and it was the first time that I've actually had a brief explanation about what information actually is. However, AskScience, it would be great if someone could go into further detail as to what information is. "
] | [
"Black holes lose a small part of their mass over the billions (potentially trillions) of years that they exist.",
"In time, when the last black hole finally dwindles its last bit of mass, would the universe be in a position like it had been at its beginning? I.E. pockets of matter spread out in an uneven array, ... |
[
"If I travel fast enough to red or blue shift radio waves, what would happen to the sound coming from a radio program?"
] | [
false
] | I realize that I would have to adjust my station to the new frequencies, but would the radio beat or tone shift up or down as well? | [
"The Doppler effect works on electromagnetic waves."
] | [
"Well, it would change the station first of all... So if you tuned in at 98.5 MHz you might instead tune in at 98.6 MHz. ",
"After that I think things should be slowed down, regardless of if it is ",
"AM",
" or ",
"FM",
". If we had a 10% elongation of the wave, we should also have a 10% slow down in modu... | [
"You could almost say that traveling at a certain rate is the same thing as single-sideband FM modulation, if you wanted to get esoteric.",
"TIL! That's a nifty way to look at it. So in both AM & FM cases, you'd hear lower pitches but stretched out signals with a red shift and higher pitches and a sped up signa... |
[
"Are Galaxies still being born?"
] | [
false
] | If there was a period of time in the Universe's ancient history when galaxy clusters were being formed, is that period over forever? Is the Universe now uniformly consisting of Galaxy Clusters and Groups? And, in the future, will these galaxy clusters (and groups) be uniformly spread out? Finally, if so, is this the way the universe will remain until it is over, or will galaxies begin interacting and colliding with one another as we near the end of the Universe? Or will each galaxy's stars simply break down into systems of spread-out black holes? | [
"I'm going to disagree with the comment by cofwjz. While stars are still forming, galaxies are no longer being 'born'. To be honest, it's even rather hard to define what being 'born' means for a galaxy. ",
"First you need to understand what a galaxy truly is. Sure, it's a collection of gas, dust and stars. But, f... | [
"Yes, galaxies and stars are still being born, but the rate at which they form has diminished considerably due to the effects of ",
"dark energy",
", which suppresses the growth of structure in the universe. For objects like galaxies to form, their self-gravity has to overcome the expansion of the universe, an... | [
"In response to seladore, I agree that it is nontrivial to define what exactly we mean by a galaxy being \"born\" today. The only sensible way to quantify the rate of galaxy formation is ",
"rate = dn(M)/dt ",
"where n(M) dM is the number density of galaxies in some narrow mass bin dM centered on mass M. And ... |
[
"If men have XY and women have XX what would happen if scientists created a YY human or if it is impossible, why?"
] | [
false
] | I already somewhat understand how reproduction works. with a mother passing on one of her X and the father passing on either an X or a Y, which would decide the sex. so would this mean that XX are very feminine, XY half feminine and half masculine, and YY some sort of super manly being? I assume a YY human wouldnt have nipples... | [
"During Metaphase I of meiosis, the sperm or unfertilized egg can incorrectly separate the duplicated chromosomes and have additional copies of sex chromosomes in one egg or sperm, and then no copies in another egg or sperm. Most of the time it causes a spontaneous abortion (miscarriage), or the sperm/egg will not... | [
"Well, the short answer is that the X chromosome has a lot of important genes on it that males require for living. Our system is sort of a \"default female\" system; meaning that we only develop into males if the proteins from the Y chromosome are present and get expressed. If there is no Y chromosome, we just cont... | [
"There are also conditions where you can have XX males and XY females.",
"De la Chapelle Syndrome and CAIS or Complete Androgen Insensitivity Syndrome, respectively."
] |
[
"Is Peak Oil frowned upon in the scientific community?"
] | [
false
] | null | [
"I understand 'peak oil' to be the time that oil production begins to decline as a result of lack of supply. Given this definition and the fact that there is a limited amount of oil available, I don't see how peak oil could possibly be a myth. Do you consider my definition to be incorrect, or am I missing somethin... | [
"Perhaps a good way to answer your question is to look at what people say who claim peak oil is not a real concern. Robin Mills' ",
" seems to me to be a pretty fair treatment (well, much more fair than the whole \"peak oil is a liberal plot!\" screeching you often see). Here's the main points from his book (in b... | [
"Can you explain what you mean, so that I know what you are exactly talking about?",
"This is important, because if you categorically claim that the Peak OIl is myth, you are actually claiming that oil extraction capacity can increase until oil resources are completely depleted. "
] |
[
"Do cravings for specific kinds of food mean anything about the nutrients my body needs?"
] | [
false
] | null | [
"I think what you're getting at is akin to, does someone with an iron deficiency crave iron-rich foods (for example).",
"As some of the others stated, deficiencies sometimes correlate with cravings, but the foods craved don't necessarily have anything to do with the deficiency. Your satiety hormones don't know t... | [
"I don't know if this is entirely the case. A biological need for a particular nutrient can indeed be tied to a craving for a particular food. Your body, on some level, probably knows something of the nutrients it is ingesting and associates these with what it is eating. In elephants, the correlation between cravi... | [
"I get spinach cravings. Maybe you're not eating well prepared spinach?",
"I feel like I frequently crave vegetables after, say, a long weekend of junk food and beer, but it's probably just confirmation bias."
] |
[
"can EDTA change the oxidation state of an ion or atom?"
] | [
false
] | null | [
"Can you give a more specific circumstance?",
"Assuming you are excluding acid-base reactions (which it certainly could since it has both acid and base groups), then no, it is rather unlikely to directly alter the oxidation state of metal ions. ",
"There could be rare cases in which the coordination of EDTA ac... | [
"Really having fun with this AAS/ICP analysis aren't you? Is this lipstick again? ",
"Well, first off, it probably isn't Pb, the conditions are pretty darn oxidizing, and ICP/AAS doesn't typically tell you oxidation state anyway. (I can't off hand think of a case in which it would.)",
"So what's going on in t... | [
"it's in an acid peroxide sol'n with lots of dissolved organic compounds; a known amount of lead nitrate and nitric acid were added to a sol'n and wasn't detectable by ICP-OES or AAS. When EDTA was added, it increased the amount of lead present by a lot. I first thought it was the matrix effects inhibiting the ... |
[
"Can hydrofluric acid be used to quicken lens grinding?"
] | [
false
] | null | [
"I will say no for two reasons.",
"First, if referring to eyeglass lenses, I don't think glass is used anymore, or perhaps very rarely.",
"Second, if glass, the precision milling needed could not be easily controlled (if at all) chemically. Also, the quantity of material to be removed would probably make the us... | [
"To add, etching glass with HF would most likely make the surface more rough. The etching process produces porous surfaces. ",
"Here is a paper where they studied the surface roughness on glass slides etched with HF. ",
"Paper",
"\nEdit: see pg 9 of the pdf "
] | [
"Could be a number of reasons you need glass instead. Maybe you need something that doesn't scratch as easily. "
] |
[
"Why does steam sometimes rise from cold water?"
] | [
false
] | null | [
"Steam or water vapor is invisible, the \"steam\" we see is really the water vapor condensing into small water droplets which scatter the light giving them their cloud like appearance.",
"This happens when the warm water vapor enters a region of cooler air. A tea kettle going into the room produces these clouds ... | [
"Essentially yes. If you watch the weather reports, you may hear the meteorologist mention the \"dew point.\" This is the temperature at which water vapor starts condensing. So when the air temperature reaches the dew point, the water vapor starts forming little water droplets which is a cloud near the ground.",
... | [
"Is this how fog forms?"
] |
[
"How does freezing sperm not destroy or damage it?"
] | [
false
] | null | [
"Your assumption is correct. When you freeze cells willy-nilly, the cells will burst as ice crystals form. Thus, they will be dead when you try to thaw them. Methods for preventing this have been developed over the last few decades, including: rate of freezing, thawing procedure, and the inclusion of cryoprotect... | [
"Donated sperm has to be stored for six months before it can be used in treatment, in order to screen the donor for infections. Sperm cells have been frozen, thawed and successfully used in treatment for more than 40 years, although not all sperm survive the freezing process.",
"Frozen sperm must be stored in ext... | [
"Yeah, but brains, being more complex and more vulnerable than sperm, are much harder. ",
"With sperm, if you kill half the cells, you're still ok, because you don't need all the cells, just most of them. ",
"With the brain, if you don't kill any cells, but they lose their connective structure, you're done for.... |
[
"How are two photons quantum entangled?"
] | [
false
] | As in, when the Chinese scientists "teleported" a photon by entangling it with another, how did they do that? | [
"You get a pair of entangled photons basically by creating it, rather than taking two photons and somehow \"entangle\" them.",
"There are many ways to do this, but a very common technique is to use birefringent crystals like barium borate. Classically speaking, this crystal acts as a beam-splitter, as it has two ... | [
"The process is super tedious, as the SPDC is a very rare event, but using a very high powered laser beam you can get a decent amount of photon pairs out of it.",
"With the by now very common ",
"periodically poled",
" crystals and periodically poled waveguides you can get decent down-conversion rates even at... | [
"There is no principle limit on how long/far away photons can be entangled. De facto we can only make use of the entanglement for a very short time: The photons leave with the speed of light and our current methods for confining the entanglement of the photons are very inefficient and lossy.",
"Storing the entang... |
[
"How are if then statements translated into their fundamental logic constructs (logic gates)?"
] | [
false
] | In higher level programming languages you have if then statements for conditional control. In the study of logic you have antecedent and the consequences with implications. I don't understand how these implications are implemented into CPU designs. Although it probably is very basic knowledge, I'm missing some kind of detail. I hoping someone here could help. I would like to know how they constructed using only logic gates such as and/or/not. Thanks | [
"The comparative operators are implemented in the CPU with subtraction. For example in all comparisons of A==B, A>B, etc. the subtraction A-B is calculated and the result's value sets CPU Flags such as the Zero Flag which indicates A==B, or the Negative Flag which indicates the result of A-B was less than zero and ... | [
"Then, the if(A==B) { becomes a conditional jump.",
"Unless it's running on an architecture that uses ",
"predicated execution",
", in which case the instructions in the ",
" and ",
" blocks are annotated with a flag saying \"do this only when the condition flag is set/not set\". ",
"(Note: some archite... | [
"First off, computer programs aren't really translated into actual logic gates. Rather, they are translated into lists of machine instructions, describing a sequence of manipulations to carry out.",
"The exact format of the instructions is defined by the electronics in the processor. Some processors like x86 have... |
[
"Questions about the compression of fissile material in a nuclear bomb."
] | [
false
] | [deleted] | [
"If I tell you, will you promise not to build one?"
] | [
"According to ",
"this article",
" you can compress plutonium to three times its normal density, and the more you compress it the higher the yield.",
"I think these devices usually have a uranium tamper that not only provides a good deal of momentum for the compression but also decreases the the amount of plu... | [
"For a typical nuclear weapon these days, it's on the order of inches. While the designs of the weapons are of course closely guarded secrets, the basic parameters aren't. The subcritical core in the first stage of a fission-fusion weapon can't be much bigger than a football."
] |
[
"Is all energy consumed by a computer turned to heat, or is some amount wrapped up in \"information\"?"
] | [
false
] | So, w/r/t conservation of energy: If you have a system with a machine that lifts a weight, and you put X amount of energy into the machine, the heat energy of the system goes up, but not by all of X, because some of that energy is bound up in the gravitational potential energy in the weight. When you drop the weight back down, then all of X energy eventually ends up as heat energy... Right? My question is: If you dump X energy into a computational device to calculate a complicated math problem, does the heat energy of that system go up by all of X? Or is some of that energy bound up in... the information from the result of the calculation(?) or something else? Like, if your computer's memory starts as a random jumble of 1's and 0's and then you spend some energy to calculate and store the first million prime numbers or something, is there energy bound up in that calculated information the way that there is energy stored in the gravitational potential energy of a raised weight, that turns back into heat when you erase the information or drop the weight? (Assume it takes the same amount of energy to store a 1 or a 0 in memory; or that the number of 0s and 1s in memory are roughly the same whether or not there is useful information in there). | [
"Essentially all of the energy you put in a computer will be converted into heat. There are some obvious conversions: heat from electrical resistance (the largest output), heat from the friction of moving parts, and sound and air flow from the system getting dissipated as heat in the surrounding environment.",
"T... | [
"Electrical engineering ",
" here:",
"Depending on the type of memory, the data may be stored in a capacitor (DRAM) or a flip flop (SRAM). Both of these store the energy in the forms of voltage, which is a potential difference in energy between two points.",
"The actual calculations are electrical energy whic... | [
"I'm not sure if it applies in this case, but much of our electrical notation is \"backwards.\" If Benjamin Franklin had labeled the electron as positive, making the positive flow of electricity the same direction as the flow of particles, we'd have some tidier math today. As it stands, positive flow is opposite th... |
[
"How exactly do animals think (if at all)?"
] | [
false
] | I've always wondered how animals process their thoughts. As a fairly average human, I filter my conscious thoughts through language - that is, everything I see, feel, desire, etc. comes across as a thought in my head, and those thoughts occur via language. So how would an animal with no spoken/written language go about processing thoughts? Or a human raised in isolation who was never taught a language? What about apes who are taught sign language, or parrots that have a vocabulary in the hundreds of words? I guess the TL;DR version of my question is when I see my cat's bowl, I think of the word "bowl". What goes through the cat's mind? | [
"After several minutes of rigorous experimentation, one black eye and a colleague who will not stop laughing, I'd like to respectfully inform you that your hypothesis sucks."
] | [
"Depends on the animal. A lot of animals don't really think, they just do. That is, they're driven almost purely by instinct. ",
"Other animals, such as monkeys, dolphins, dogs, rats, and so on, you can watch them 'think' and see the proverbial wheels turning in their head while they figure something out. I c... | [
"I have no expertise on this matter.",
"What I've noticed is that my thinking happens in at least two steps. First I have a thought, which is a quick impulse and triggers the next step. The next step is to put that thought into words. The second step takes much longer. As an experiment, I sometimes attempt to ski... |
[
"Can non-highlighted posters please post any credentials you have related to science when you post?"
] | [
false
] | What about suggesting/requesting this on the right side column? | [
"It shouldn't be necessary. Incorrect answers tend to be accurately downvoted already."
] | [
"It's kind of a pain to type this every time I respond. Plus it always sounds like I'm bragging or something along those lines."
] | [
"Yeah I was 17 too once. Dear lord would I smack that kid around some now. That being said, I think shadydentist is right that a lot of these posts get well moderated by up/down votes. I personally have only gotten active in this forum for the last few weeks, but I've been watching a lot of threads. The unscientifi... |
[
"Is there anything in nature that is sweet and poisonous?"
] | [
false
] | I heard recently that evolutionally, humans have a predisposition to sweets because there is nothing in nature that is sweet and poisonous. Is there any merit to this? Is there anything in nature that is sweet and poisonous? Are we drawn to sweets because of evolutionary traits? | [
"Lead tastes sweet. In fact,it has been used to sweeten wine by the Romans. It wasn't a good idea. "
] | [
"Ethylene glycol (common antifreeze) is sweet and poisonous, but I am unsure whether it occurs in nature. One thing that both occurs in nature and is sweet is one of the lead salts called \"sugar of lead.\" ",
"The broad truth is that all substances are toxic if taken in large enough amounts. Water, when taken... | [
"Right, of course everything in moderation. I mean more like in plants and animals. ",
"But lead is a really good answer, thanks. I kind of want to go lick some now. "
] |
[
"Is the plane of our solar system within the plane of the Milky Way? If so, do they spin in the same direction?"
] | [
false
] | If so, why is. . .those things? Edit: when I say "within the plane" I mean "on the same plane". | [
"No. They are offset by about 60",
" from each other.",
"The sun and planets trace a path through the sky called the ecliptic. This represents the plane that our solar system orbits on. In reality it's not a completely flat plane, but it's close. If you watch the path of the sun during the day you can get a rou... | [
"There is no reason why it should be on the same plane. The 60",
" offset is just the way things happened when our solar system was born in a cloud of interstellar gas. It could have been any angle, and in other stellar systems it happens to be other angles.",
"Try to think of it as being kind of like the atmos... | [
"Our solar system also moves \"up and down\" along a sinusoidal wave relative to the plane of the Milky Way."
] |
[
"Are neonicotinoids 'bee killing' pesticides?"
] | [
false
] | The EU is talking about banning neonicotinoids, and everybody is raving about how this is evidence based policy. I can see there is some evidence that neonicotinoids kill bees, but it's not obviously conclusive (from my very quick scan of the literature). These kinds of questions have been asked a few years ago, but I believe significant new evidence has come out since, so I think it's worth asking again. Edit: thanks for all the answers so far. I just wanted to clarify: I suppose the point in the question is - if they ban neonicotinoids, would that have a significant positive effect on bee populations? Of course, many of the answers have addressed that, and answers to the unclarified question are still appreciated. | [
"\"Neonics\" are insecticidal chemicals that will kill pretty much any insect including bees. The problem is with application. No one is spraying bees with insecticide (maybe some peoole are idk) but their use leaves large residual ammounts in the environment which eventually get back to the bees since they tend to... | [
"Neonics are very persistent in the environment. Some pesticides stick around a long time, some are gone very quickly. That's part of the problem; neonics stick around and become an issue for non-target species. I deal with pesticides daily in my career and these are indeed a problem. I support a ban, because we h... | [
"Neonicotinoids are pesticides similar to nicotine, a natural insecticide in tobacco. Like most pesticides, they are categorized based on their application. In this case, they are a general insecticide that will target any insect that comes in contact with it, affecting their nervous system. Bees are natural pollin... |
[
"How do bacteriophages have the energy to inject their DNA into cells?"
] | [
false
] | I've been curious for a long time about how viruses, specifically bacteriophages, are able to move, seemingly on their own, once they are attached to a cell. I am talking about the plunging that they do in order to inject their DNA into a cell. This seems like much more focused movement than what they do until they come around to the right kind of receptor, right? After some Wikipedia reading, I came across this paragraph: However, I do not understand reversible nor irreversible binding, and I'm hoping someone here might be able to explain this in slightly less technical terms. Here's the question as succinctly as I can pose it: How to bacteriophages summon the energy to plunge into a cell? Thanks for considering this question! | [
"Antiviral biologist here, not a biochemist though. It's a series of chemical reactions similar to the way proteins can change their conformation as a result of a single binding. In the simplest terms, when the phage connects to the membrane, the difference in polarities at the binding site creates a cascade of c... | [
"To put what crackadillicus said a little more simply; There are proteins that can also \"snap outwards\" to the same effect, I imagine that it is probably just a larger mechanism of one of these. Hemagglutinin in Influenza is one of the cooler examples of this :) ",
"http://www.pnas.org/content/94/26/14306/F1.ex... | [
"Then you will love this one about production of hemoglobin. I do not think it is actually a simulation, but it has a strangely realistic touch. Might be the sound effects.",
"http://www.youtube.com/watch?v=GkdRdik73kU"
] |
[
"Energy Production Area Usage Question"
] | [
false
] | Hello people of , I have been reading about different energy production methods and have become more and more interested in nuclear energy, the LFTR especially makes me interested. And I started to think of space usage. Obviously, wind and solar farms need to take up a lot of space. But how much space is that? So what I am asking for is a comparison between how much area is needed to produce the same amount of energy for each energy production type (Wind, solar, nuclear (both today's current reactors and LFTR). Thanks! | [
"I would recommend watching the TED talk by David MacKay, ",
"TEDxWarwick - David MacKay - How the Laws of Physics Constrain Our Sustainable Energy Options",
".",
"He's the author of the book ",
"Sustainable Energy - without the hot air",
", which is an amazing book for examining sustainability with elect... | [
"Awesome! Thank you very much, I shall watch this right away"
] | [
"There's a thread over at the ",
"EnergyFromThorium forums",
" that tries to visualize the energy density of different sources of energy.",
"This post",
" have a very nice graph that shows how many % of earths land mass is required to produce all the worlds energy demand 2010 using different energy sources.... |
[
"Do we know why those with Autism/Aspergers/ASD tend to fixate and obsess intensely over certain perhaps unusual things?"
] | [
false
] | I have ASD and I've always wondered this. I was thinking that in a similar way to the proposed model of Aberrant Salience for psychosis (which says that psychotic symptoms first emerge when excess dopamine leads to the attribution of significance to stimuli that would normally be considered irrelevant), a similar thing happens in ASD. Am I on the right track or am I completely off? | [
"The neurolobiokogy behind autism is way more complicated than that behind schizophrenia. We simply don’t know currently. That’s why there’s no FDA approved drug to treat autism, unlike ADHD, Schizophrenia, or depression. ",
"The FDA does approve some antipsychotics to use in autism but only for autistic agitatio... | [
"Treat and cure have slightly different meanings in English. When we treat a disease, we're just making it better, but when we cure a disease, we make it go away. Some treatments lead to cures, but not all."
] | [
"A lot of a misinformation here so I thought I’d pipe in.",
"So far what we think could be the cause of ASD, or at least connected to ASD, is failed apoptosis in the cerebral cortex. Apoptosis is planned cell suicide, and failures in apoptosis are implicated in various diseases, most notably cancers, tumours, and... |
[
"Quantum Diffraction of a Macroscopic Object"
] | [
false
] | In Chad Orzel's book 'How to Teach Physics to your Dog,' he explains that a 20 kg object (dog, in this case) has a wavelength of 10 meters. To diffract around a ten centimeter barrier, the object's speed would need to be 10 m/s. Am I wrong in thinking these speeds could be achieved by cooling to near absolute zero? Would it be possible to diffract a macroscopic object if cooled enough? | [
"lambda (wavelength) = h/p = h/(mv)",
"To diffract around a 10 cm (.1m) barrier: .1 = h/(20kg * v) -> v = h/2 m/s",
"That's around 10",
" m/s. T = mv",
" /(3 k_B ) where k_B = 1.38e-23",
"that's around 10",
" degrees K... The lowest temperature ever attained with a few atoms is 10",
" K. I don't thi... | [
"No, to my knowledge bucky balls which are predictable, have been shown to have a DB wavelength and show quantum behavior under certain circumstances.",
"The point of this was simple; it's unknown. We can't test those systems, so we can't say anything about them except what they would probably do."
] | [
"Would it be possible to diffract a macroscopic object if cooled enough?",
"I would hazard a guess: probably not. The state of a macroscopic object is coupled to the state of its environment in a thermodynamically irreversible manner. This results in quantum decoherence, which is one of the reasons macroscopic ob... |
[
"How does vaccinating trees work?"
] | [
false
] | I was walking on the street when I saw two guys in high Vis coats injecting a tree with something. When I asked them, they told me they were vaccinating the tree. I never realised that plants could be vaccinated or that they had something like an immune system. Could someone knowledgeable on this explain how the vaccine works, what kind of vaccines are available and for what plants and what they can protect against, and how long they last? | [
"I think he over simplified what he was doing, but it was most likely some sort of fungicide or bactericide. The only case I know where it is commonly use is for ash dieback, a fungus transmitted by the emerald ash borer. It's a good way to make sure it is transmitted through all the tree's system."
] | [
"I am unaware of any adaptive immune responses in plants (ie what a vaccine would work on). There are some attempts to prime the innate immune responses in order to illicit a stronger response, but that is not a vaccine.",
"[",
"source",
"]"
] | [
"Ah that makes sense. It's still interesting that you have to inject a bactericide or fungicide for it to spread well.",
"I found this article and assumed that it was a vaccine, but actually reading it, it seems more like what you described. ",
"https://www.newscientist.com/article/mg16021641-100-a-jab-for-tree... |
[
"Theoretically, what would happen to a mother and child if the umbilical cord was never cut?"
] | [
false
] | Professor did not have an exact answer. Just a question, what would happen if up to say, age 20, the cord just wasn't cut? (all this is in theor, of course.) | [
"Well, considering that the umbilical cord is connected to the placenta, and the placenta is \"delivered\" by the mother within hours after childbirth, not much would happen if you leave it attached. Some people actually do leave the umbilical cord connected -- it will dry up and eventually fall off after a few day... | [
"Well, nothing happens to the mother because the placenta gets comes out very shortly after the baby is delivered - it gets detached from the her...as for the baby, I can't imagine much happens - it'll just just be a gross, stinky mess having to lug a baby and placenta around."
] | [
"Thank you. Didn't know what to expect for answer but thank you for such a straightforward one."
] |
[
"Why would the food industry use embryonic human cells in the production of \"flavor enhancers?\""
] | [
false
] | It's a link to an anti-abortion group American Life League, so don't click if you don't want to give them hits. The gist of the article is Senomyx Biotechnology produces flavor enhancers for food giants—Nestle, PepsiCo, Cadbury Adams LLC* (a Kraft company) and Solae—using aborted fetal cells HEK-293 (human embryonic kidney), which were taken from an elective abortion in the 1970s. What do food companies use human cells for? Is this something worth getting upset about? | [
"Senomyx used that cell line to ",
"test how receptors respond to taste",
". They ",
" \"produce\" flavor enhancers using those cells - that's at best misleading reporting, and at worst complete libel, to further ALL's agenda."
] | [
"HEK 293 cells are a very widely used cell line. Damn near every biology research institution in the US and Europe has a vial or two of them frozen down somewhere. I think I have a few in my storage tank. ",
"Yes, they originally came from an aborted fetus, but they are a stable transformed cell line. This means ... | [
"I was looking for information from knowledgeable sources. I'm not exactly sure what you're implying, but I definitely was skeptical of the article, especially considering the organization that posted it. "
] |
[
"Is there a \"complexity threshold\" at which a sound wave becomes unintelligible to our brains?"
] | [
false
] | One of the special features on a DVD I own has all of the episodes from the disc play at the same time (more like "annoying feature," amiright?). As an experiment, I tried to pick up any of the dialog from one of the 12 or so scenes but really wasn't able to. With so much language being spoken, my brain couldn't follow any of it. Is there a known complexity level, so to speak, at which our brain can't distinguish individual sound sources? And, does it vary for language vs. environmental sounds? For example, is this "confusion" threshold lower for language patterns than it is for picking up non-language sounds against a crowded non-language noise field? | [
"There isn't really such a known level. In fact, there isn't even a reliable way to measure the complexity of speech in noisy environments.",
"There are a lot of factors that contribute to how well we can understand the speech (the \"speech intelligibility) of a given speaker (the \"target\") when other conflict... | [
"This is a really great response. Thank you. My understanding of hearing is that the brain is basically doing a Fourier transform. Do you know if anyone has looked at the signal complexity itself to see if there are anything approaching objective measurements? "
] | [
"It is more complicated than an ordinary Fourier transform. And it isn't the brain doing it, it is the inner ear itself. Different parts of the inner ear respond to different ranges of frequency. This means the sound is broken up into overlapping, asymmetric, roughly logarithmically spaced frequency bands. Furt... |
[
"Electrons and Double Slits"
] | [
false
] | I keep hearing how observing Electrons passing through a "double slit" produces a pattern like a particle, but not observing produces a wave [interference] pattern. Is this as literal as it sounds? For example, when you power on the observing machine it flips to a particle pattern and when you power it off it abruptly changes back to an interference pattern? That sounds crazy, but I understand the whole concept is crazy anyway. Have any of you science Redditors actually observed [or not observed] this? | [
"Is this as literal as it sounds? For example, when you power on the observing machine it flips to a particle pattern and when you power it off it abruptly changes back to an interference pattern?",
"As long as you understand that the \"observing machine\" is not independent of the system. It makes as much of an ... | [
"I hate this video, not only because it's an excerpt from a video promoting a cult, but also because it's implications are totally false. The video implies (and the aforementioned cult hinges on this implication) that the electron is aware it's being watched ",
" any sort of interaction.",
"This is wrong becaus... | [
"I hate this video, not only because it's an excerpt from a video promoting a cult, but also because it's implications are totally false. The video implies (and the aforementioned cult hinges on this implication) that the electron is aware it's being watched ",
" any sort of interaction.",
"This is wrong becaus... |
[
"What about the other 99% of electrons NOT in the outer shell? Do electrons in complete inner electron shells do anything interesting?"
] | [
false
] | null | [
"You are correct in the second sentence: Because electrons are indistinguishable there is no meaning behind saying that they swap orbitals. ",
"To put it another way, if two electrons swap spots it's exactly the same as if nothing happened"
] | [
"I can't answer for what they do chemically, BUT they definitely are still important physically.",
"For example:",
"Most X-ray generating tubes work by bombarding a material with electrons, seeking to knock out inner shell electrons. When these inner shell electrons get knocked out the electrons in higher level... | [
"The inner electrons play a role in certain nuclear decays, like ",
"electron capture and internal conversion",
"."
] |
[
"Classical explanation of radiation pressure?"
] | [
false
] | I understand Maxwell's prediction, that the oscillating electric component of the wave will oscillate a charge perpendicularly to the wavefront, and the magnetic component will then give a net force in the same direction of the wavefront. This only explains the phenomenon for a charged particle though, and from this explanation, a neutral particle would not experience a force, and hence should not experience radiation pressure. But experiment shows that even neutral surfaces will experience radiation pressure. So, from a classical em wave point of view, what is happening? | [
"I don't really know of any acceptable answer other than to say that it is a property of the E (electric) and B (magnetic) fields to carry momentum, because if they did not then conservation of momentum would not be satisfied. A bunch of math can be done to show this is the case. And from that more math can be do... | [
"I understand arguments for why the wave must carry momentum, but how does it transfer this momentum classically?"
] | [
"If you understand that the fields carry momentum then I'm not quite sure what your problem with E+M waves in particular is. If a wave has momentum then clearly when it hits something momentum will be transferred (based on the properties of the object that it is hitting), since the light momentum is no different t... |
[
"Does the use of microwave ovens distort chemical structures in foods resulting in toxic or otherwise unhealthy chemicals?"
] | [
false
] | null | [
"Yes, microwave ovens distort chemical structures in foods. The heat from the microwave energy causes proteins to uncoil and change their shape, causing their texture and flavor to change. This phenomenon is known as \"cooking\", and is the same whether you microwave, boil, bake, or fry food."
] | [
"Piggybacking the top comment, microwaves actually create ",
" harmful chemicals than most other cooking methods. Any cooking method that creates char or browning (grilling, frying, searing, and even baking) creates carcinogens. Microwaving has a hard time creating char because it primarily boils the water in t... | [
"Way too late to the party but I literally did my human nutrition MSc dissertation on how cooking methods alter nutrient content so figured I'd contribute anyway, especially since that info hasn't been of much use anywhere else up to now! Microwaves don't radiate your food, as many believe, they simply excite water... |
[
"How are eyeglass lenses made and cut? How are existing lenses tested for prescription?"
] | [
false
] | null | [
"Episode of ",
"How It's Made",
" may shed some insight."
] | [
"Lenses start as \"semi-finished\" blanks, that look like hockey pucks. They are cut or \"surfaced\" by a diamond or carbide blade in a computer controlled machine called a \"generator.\"",
"Lenses are measured or \"neutralized\" in a machine called a lensometer, or vertometer.",
"Prescriptions are measured mai... | [
"In terms of measuring the prescription, a piece of equipment called a focimeter is used. It looks a lot like a microscope.",
"With the manual type, the lens is gripped on a table, and you view through an eyepiece a lit 'grid' which is projected through the lens. There is a dial on the side of the focimeter, and ... |
[
"Do Most Comets Orbit in the Same Plane as the Planets?"
] | [
false
] | null | [
"There are three(ish) types of comets. Inner solar system short period comets, outer solar system short period comets, and long period comets. A typical inner system short-period comet might be something like ",
"9P/Tempel 1",
", which orbits the Sun every 5.6 years, and has an orbital inclination of 10.5 deg. ... | [
"No, that's still not right - Earth's axial tilt is 23.5°."
] | [
"Not sure where you got that 29.29° figure, but the orbital inclination of Earth is 0° by definition. The other planets are ± a few degrees from that."
] |
[
"What would it take to alter the earth's rotation?"
] | [
false
] | I thought this would be a simple "I'll Google that" but it was not. What I mean is, what would it take to speed up or slow down our rotation? has some pretty interesting stuff, but not what I'm looking for. Anyone out there know where I should go to look for this? | [
"This can be calculated via energy equations. Basically you are going to need something that has a significant mass compared to the mass of the Earth...which you can't really get from on the Earth. Your best bet would be to make use of some extraterrestrial energy source, like an rogue small exoplanet heading som... | [
"To make that kind of change in the moment of inertia you would need to have a huge change in the geometry of the planet, or add a hell of a lot of energy from somewhere. The first is impossible. The second would require a asteroid/planetary impact of such magnitude that changing the length of the day is the least... | [
"I'm not sure what you mean. Even if you just sit down (move your center of mass closer to the Earth's) you'll speed up it's rotation slightly. Everything that interacts with the Earth has an effect on it's rotation. Perhaps a notable one is as the Moon moves farther away the Earth slows down. In about 2-3 bill... |
[
"What is the biochemical origin of caffeine dependence?"
] | [
false
] | There's a joke that if you've been drinking coffee for a long time, when you wake up you'll need a coffee to get you back to the point where you were before you started regularly drinking coffee. But, if you stop for a week or two, your baseline goes back up. What happens to regular coffee drinkers to lower their baseline wakefullness, and is it chiefly neurological or psychological? | [
"Caffeine is a nonselective adenosine receptor antagonist, acting at A1, A2a, A2b, and A3 receptors (it also binds to a few other receptors, but we’ll ignore those for simplicity’s sake). From knockout studies in mice, it appears A2a is critical for the stimulating effect of caffeine. In the brain, Adenosine levels... | [
"Antagonist meaning that caffeine binds to the adenosine receptor and blocks adenosine from binding. Importantly, caffeine binding to the receptor produces no effect. Conversely, adenosine binding to the same receptor would cause an effect (adenosine is an agonist).",
"\nUpregulate simply meaning the cell increas... | [
"Can you define antagonist and upregulate in this context? Thanks!"
] |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...". Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists. Please only answer a posted question if you are an expert in the field. . In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for . If you would like to become a member of the AskScience panel, . Past AskAnythingWednesday posts . Ask away! | [
"Why is it that SSRIs treat so many things? Is it that depression, bipolar disorder, anxiety etc. are all related in some way, or is it that serotonin modulation just happens to alleviate each of them through different mechanisms?"
] | [
"Bisphenol A is still a topic of discussion among health agencies; however, many of the bans in place today are purely to allay growing public concerns. In 2011 the EPA listed BPA as a non health concern. BPA is a naturally occurring hormone that is incorporated into products such as the lining of food cans, water ... | [
"Serotonin is involved in many aspects of mood regulation and anxiety, but it's not entirely clear why serotonin agonists alleviate symptoms. That said, it's generally not advised to treat bipolar disorder with SSRI medications, as research has indicated that they are correlated with hypomanic or manic episodes, th... |
[
"How does melatonin exactly work in regard to sleep? What are the physiological mechanisms that are implicated?"
] | [
false
] | I can't seem to find anything on how it exactly works. | [
"Hey there. This is a biochemistry question, with an answer that will (essentially) be gobbledygook if you aren't a biochemist.",
"A short example of what im talking about here:",
"\"Melatonin is a derivative of tryptophan. It binds to melatonin receptor type 1A, which then acts on adenylate cylcase and the inh... | [
"This helps immensely so thank you very much. Ive read in a few articles that the mechanism is still relatively unknown but i wasn’t sure if that was an isolated fact or not. But yes thank you a lot"
] | [
"serotonin is converted to melatonin",
" in the pineal gland, a small endocrine gland located in the brain near the hypothalamus.",
"When there is light, the eyes receive this light and send signals via the retinohypothalamic tract to the hypothalamus (specifically, the suprachiasmatic nucleus). This in turn si... |
[
"[physics] How does gravity differ across a planet?"
] | [
false
] | There is a post in about a gravity map of the moon. It varies. How does this occur? My limited understanding is that gravity is determined by mass, the more mass the greater the gravity. This is also affected by the density of the mass, with both mass and density playing together to make gravity. So is the variation in gravity across the moon (or another planet) due to pockets of more dense elements? Is it just averaged out? How does the fluctuation in gravity across the earth affect the orbit of say, the It's? | [
"This is the image",
" you're referring to? Which annoyingly doesn't have a legend to tell you the values. They do say that red corresponds to high mass values and blue are low values.",
"It's important to note that when you learn about calculating gravity in your physics 101 class you are treating them as poin... | [
"The ISS has about 90 percent the gravity of the earth. That's ~100 Gal (100,000 mGal). That's a huge difference when doing calculating anomalies compared to the ~100 mGal difference on earth. This difference is included when they do their corrections (free air). Again, without knowing the actual values I can't... | [
"They're on a linear scale. The measurements are just really small. "
] |
[
"If you drop something made of glass and it doesn't break, does it weaken the glass at all in case you drop it again?"
] | [
false
] | [deleted] | [
"I'm sorry, but the unhelpful (but true) answer is: it depends. ",
"If you dropped just plain glass that has not been toughened or coated, yes, it will weaken. This is because you would introduce microcracks in the glass which would then act as stress concentrators that amplify future stresses.",
"If you droppe... | [
"This guy knows what he's talking about. Most glass is very brittle, meaning that when you subject it to loading it only deforms elastically. Elastic deformation is completely reversable and is the result of the bonds between atoms stretching like rubber bands, once the force is removed the bonds return to their ... | [
"Pyrex is a brand name.",
"In the USA it used to be made of ",
"borosilicate glass",
", however now uses ",
"soda-lime glass",
" (with regard to kitchenware, lab equipment under the Pyrex brand is still all borosilicate in the USA). Any US Pyrex pre-1998 is borosilicate."
] |
[
"What would happen to the structure of a radioactive diamond as it decays?"
] | [
false
] | For a diamond made entirely of carbon-14, which I understand undergoes beta minus decay into nitrogen-14, what will happen to its tetrahedrally bonded structure as individual carbon atoms decay, and are replaced by nitrogen atoms? One idea I had was that the nitrogen escaped the structure leaving gaps in the lattice. If this occurs, would the diamond then conduct electricity, (given a significant proportion of the carbon had decayed) since some carbon atoms will be only bonded to 3 others, and will therefore have free electrons, similar to graphite? Also, if the nitrogen were to escape, would it have to form nitrogen molecules as it does so (and therefore two adjacent carbon atoms would have to had decayed?), or would it leave the structure as singular nitrogen atoms? Finally, could the nitrogen remain tetrahedrally bonded in the structure (forming four bonds to adjacent atoms rather than the usual three)? If so, after all of the atoms have decayed, what would you be left with? Bonus question: would a diamond made of carbon-14 look any different to a regular diamond, i.e. refract light any differently? Sorry this question is so long, but I'd be interested to find out what occurs, or if I have misunderstood the idea completely. | [
"I'll take a naive stab at it: diamond is basically silicon in many, many ways. They are both group IV atoms that form diamond lattices that result in semiconductors. The real difference is that the bonding is stronger in diamond which is why silicon, as a semiconductor, has a bandgap of Si is 1.1 eV where diamon... | [
"There is a thing called ",
"Nitrogen Vacancy Center",
" which is a Nitrogen atom replacing a C atom in a diamond next to a vacancy (missing C atom), so energy from the radioactive decay might promote the formation of such a vacancy (I don't know about the energies involved, so I cannot say how often this will ... | [
"It's not an easy question to answer as atomic diffusion rates can vary by something like 10 orders of magnitude. Substitutional diffusion (i.e. jumping from a crystal lattice site to another crystal lattice site) is understandably slower, all other things being equal, than interstitial diffusion (an impurity atom... |
[
"Are memory techniques bunk? Is it actually possible to develop better memory?"
] | [
false
] | I have a bunch of formulas I need to memorize for school: is it really possible to become a person with great memory for abstract numbers/equations if you have never had mind for memorization before? | [
"Well, from the cognitive psych I can remember, the short term memory uses something called ",
"\"chunking\"",
" (~mnemonics when people do it actively) to store information for quick recall, so if you broke your formulas down to simpler chunks, you could potentially remember them more effectively. The problem ... | [
"I definitely think this is true, but it's a skill that needs to be developed and takes an investment of time and effort to get results. Our brains are wired to be good at remembering some types of information (e.g. unusual things, emotional moments, stories, music) but not so good at others (strings of data like a... | [
"Memory techniques aren't really about \"developing\" your memory. An analogy could be that of a man using a lever to lift an object. Has he developed his strength? No. He has learned a trick that exploits the laws of physics.",
"In much the same way, mnemonics exploit how your mind works rather than boost your m... |
[
"More prime numbers: Why can't we make a formula to determine every prime number, or \"predict\" which numbers will be prime?"
] | [
false
] | Why can't we make a formula to determine every prime number, or "predict" which numbers will be prime? I know there are certain numbers that have a non-negligible chance of being prime before you actually evaluate them for primality (such as Mersenne Primes), but why can't we actually develop a rule that lets us easily determine what all the prime numbers are? Thank you! | [
"What do you mean \"determine every prime number\"? We do have all of the following:",
"The problems are: (a) there's infinitely many of them, so if you try to make a list they never run out, (b) the algorithms for determining that a number is prime are very computationally intensive: it takes a lot of time, rel... | [
"Yes, but he is asking for a \"formula\" that can predict the primes. I can't really answer because I don't know anything about number theory. But, the closest we have I think is riemann hypothesis. "
] | [
"There are ",
"explicit formulas",
" for the nth prime, but they're not efficient."
] |
[
"How did extremely large dinosaurs with tails, e.g., amphicoelias fragillimus, mate?"
] | [
false
] | null | [
"Someone has wondered this before",
"This is at a museum in Spain."
] | [
"This is a great demonstration but the OP is asking about much larger creatures. The Amphicoelias is a sauropod, and was an herbivore. The T-Rex or similar was much much smaller by comparison. ",
"Obviously these animals reproduced successfully, but I think the answer of how may come to speculation at this point,... | [
"Although there is no fossilised evidence of any Dinosaur with a penis we can look at animals today to answer this question. ",
"Modern Birds are a living members of the Dinosaur clade, by looking at the earliest bird species, the Ratites, we find reproductive appendages in the males that we can call penises. So ... |
[
"If I were traveling at the same speed as an electron, would I observe it generating a magnetic field?"
] | [
false
] | In other words, I know that a moving electric charge produces a magnetic field. So assuming there was a lone electron flying through empty space and I could match speeds with it and observe it while travelling parallel to it. Since, from my frame of reference, neither of us are moving, is it generating a magnetic field? If not? Intuitively I would think someone traveling slightly slower WOULD observe a magnetic field. I know this is somehow deeply tied to the questions which sparked Special Relativity, I can never find a good answer as to WHY though. It's been bugging me since I first started learning about Maxwell's Equations. Thanks! | [
"Your idea is correct, but in reality you see a magnetic field no matter what.",
"If the electron were a point charge ",
", the magnetic field it produces would be zero in any frame where it's not moving. And in any frame where the electron ",
" moving (no matter how slowly), the magnetic field would be nonze... | [
"Still scratching my head about how the \"non-intrinsic\" field can be zero for one observer and non-zero for another. In possibly a naïve point of view, it seems like that indicates it both exists and doesn't exist at the same time.",
"The same can be said of a lot of things. Kinetic energy, for example. In a fr... | [
"I thought that was a \"different\" phenomenon than the magnetic field generated by the moving charge?",
"Classically, they are exactly the same. If you have a charged object and you rotate it, it has a magnetic dipole moment because there is moving charge.",
"But quantum-mechanically, you can't really associat... |
[
"If PI has an infinite, non-recurring amount of numbers, can I just name any sequence of numbers of any size and will occur in PI?"
] | [
false
] | So for example, I say the numbers 1503909325092358656, will that sequence of numbers be somewhere in PI? If so, does that also mean that PI will eventually repeat itself for a while because I could choose "all previous numbers of PI" as my "random sequence of numbers"?(ie: if I'm at 3.14159265359 my sequence would be 14159265359)(of course, there will be numbers after that repetition). | [
"\"As it turns out, mathematicians do not yet know whether the digits of pi contains every single finite sequence of numbers. That being said, many mathematicians suspect that this is the case\"",
"http://www.askamathematician.com/2009/11/since-pi-is-infinite-can-i-draw-any-random-number-sequence-and-be-certain-t... | [
" In addition to this, is that mathematicians don't know whether pi is a normal number or not, that is, whether every digit occurs equally often. It's suspected that pi is a normal number, though."
] | [
"Yes, that's why it's ",
". Not proven."
] |
[
"Relativity and mass - how is it that matter gets more massive with increasing velocity if mass is imparted to matter by particles?"
] | [
false
] | I'll admit, I'm a bit baffled by all this. After a sci-fi movie binge, I got thinking about space travel. I stumbled upon travel through constant acceleration. I further read that the reason why traveling faster than the speed of light would not be possible under these conditions is because a spaceship would get more and more massive as velocity approaches c. I tried and made sense of it through different sites, but I couldn't find answers. Firstly, is it true that a spaceship approaching the speed of light would get too massive and therefore require too much energy to accelerate further? Secondly, I was under the impression that mass was imparted to matter by particles (perhaps the Higgs?). If that's so, how can objects get more massive with increasing velocity? | [
"Things don't actually get more massive as they approach the speed of light. That's a persistent myth about relativity.",
"However, mass isn't just the sum of individual particle masses: it's the total energy the objects have at rest. That's why nuclear fusion and fission can release energy: because the daughter ... | [
"The amount of matter in the system does not change with speed.",
"The amount of energy the system has does change with speed.",
"The myth is that since an object takes more energy to accelerate to faster speeds, then its mass has increased, because a heavier object would also require more energy to accelerate ... | [
"There is indeed a quantity called the invariant resting mass of the whole system, that gets bigger, if you increase the particles' speed.",
"In special relativity you form the so called four-momentum of a particle by combining its energy and momentum: (E/c, p) where p is a three-dimensional vector. From this obj... |
[
"Can electricity wear down conducting media, like wires?"
] | [
false
] | I know transistors can be worn down by flowing current, but can wires/cables too? | [
"Yes, it can!",
"We typically think of electronics failures as a mystery, just throw it away and replace it if it fails. But electronic failure mechanisms is a growing research field, and the physics behind many electronics failures is quite fascinating. There are many different phenomenon that cause electronic... | [
"It's a growing problem in new designs for computer chips that have 3D integration. 3D integration meaning that, since we're basically at the limit for how many MOSFETs (the transistors that drive modern computer chips) can be crammed per area, there is a push to essentially have multiple layers of these things. I... | [
"If this is real, why don't we have copper flowing out of wires and into the next adjacent circuit element?",
"He's talking about the wire breaking down, not a flow of the metal at a macro scale.",
"Basically, you can see this with the wires becoming brittle, cracking internally or the resistance in the wires b... |
[
"Is it better to inhale bad fumes through the mouth or the nose?"
] | [
false
] | if you absolutely have to breath in bad fumes, is it better for your health to go through the nose hair filters (but through the olfactory receptors which worry me as it's a short path to neurons) or directly to the lungs? If it depends on the type of fumes, what are the general guidelines and why? | [
"Not an expert, but nose has hair and secretes mucous to help with some things. Olfactory receptors slowly regenerate because they are exposed to caustic materials."
] | [
"Wouldn't it be throat and esophagus versus throat, esophagus and nasal passages?",
"Or do the nasal passages absorb a significant part before it goes to the pharynx?"
] | [
"(Neuroscience undergrad here!) ",
"The olfactory bulb is one of two places in the human brain that holds neural stem cells, the other area being in the hippocampus where memories are formed throughout life. Here are a few papers on the subject:",
"Pagano et al., 2000",
"Gritti et al., 2002",
"Gage, 2000",
... |
[
"How is it that it can be so light outside in the middle of the night in winter, in particular when snowing?"
] | [
false
] | It's nearly midnight and the sky has a very orange glow with everything outside easily visible. | [
"I guess if you live in a very light poluted area, and it snows, the snow scatters the light all over the place as it is crystals of frozen water. The have a refraction index and can redirect light so it might appear brighter. The same reason the winters with snow are usually brighter than the ones without. Asphalt... | [
"You must live in a light-polluted area. The color you describe sounds like the sky I had when I lived in northern New Jersey - it's the sum of a zillion streetlights and signs. In a less populated area, you will not have an orange glow, believe me (telescope owners travel just to experience that)."
] | [
"As the others have said, you must be in an area with high light pollution for what you are seeing to be emphasized when it is snowing (ie, when it is cloudy). Light from streetlights and such reflects off clouds and somewhat illuminates everything on the ground even if there are not streetlights immediately nearby... |
[
"Do superconductors conduct heat with no resistance?"
] | [
false
] | Since electrons encounter no resistance, I was wondering if a superconducting material would transfer heat with little to no resistance meaning it could stay in the material indefinitely. So for further context imagine cooling a solid chuck of superconductor and throwing it into the vacuum of space. If nothing acts upon the superconductor to heat it, would it stay cold forever, or would it eventually normalize? If the vacuum of space is throwing the experiment off with radiation, etc. then what about a perfect earthly vacuum. Would it always be cool, much like a superconductor would always retain electric current? | [
"No, superconductors actually have lower (electronic) thermal conductivity than a normal metal. This is sort of expected because superconductivity arises at low temperatures from a large amount of coherence between electrons, while heat is (very loosely) a measure of disorder, and superconductivity is killed at hig... | [
"In addition, superfluids, which could be pictured as electrically neutral superconductors, are very good thermal conductors. The reason is that heat is transported by convection, which is very easy in superfluids, rather than diffusion.",
"For instance, the magnets used at LHC are cooled by not simply liquid hel... | [
"heat is transported by convection, which is very easy in superfluids, rather than diffusion.",
"Do you mean the second sound?"
] |
[
"Does drinking coffee, or consuming other diuretics, result in a net loss of water from your body?"
] | [
false
] | I know diuretics cause increased urination, but since coffee and tea are mostly water, does my body wind up with more or less water than if I had not consumed any liquid? | [
"It's still a net gain. If you drink 100 ml of coffee, you'll pee slightly more than if you had drunk the same amount of water, but you're not going to pee away all 100 ml of that fluid.",
"You can survive just fine if the only liquid you consume is in the form of caffeinated drinks. You might have symptoms of mi... | [
"Caffeine has generally been thought to be a diuretic, ",
"though the extent to which that claim is true",
" ",
"has been called into question as well",
". At any rate, the amount of water you would consume from drinking tea or coffee would more than compensate for any diuretic effect."
] | [
"If this were not the case, I would have shriveled up long ago.\nFrom a New York Times article March 4, 2008",
"Investigations comparing caffeine with water or placebo seldom found a statistical difference in urine volume, the author wrote. “In the 10 studies reviewed, consumption of a caffeinated beverage result... |
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