title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How can I predict whether a salt will retain its paramagnetism in solution?"
] | [
false
] | I am not a physicist, but am having to brush up on my understanding of magnetism for my biology undergraduate thesis. Thanks in advance for hearing me out: I am trying to establish (manganese II chloride) (at which point, it is assumed that it would dissociate into its constituent ions). In a moment of redneck engineer... | [
"It just depends on whether the metal ion's spin state changes when it is aquated. Aqueous manganese(ii) [Mn(H20)6]2+ does remain paramagnetic in solution. I don't understand how the experiment you ran was supposed to detect this though."
] | [
"You're thinking of electric dipoles, which are different from magnetic dipoles. Electricity and magnetism are, of course, just two manifestations of the same underlying phenomenon, but electric dipole moments and magnetic moments of molecules nonetheless differ in their cause and behavior. The former come from the... | [
"Thank you kindly for the reply!",
"The line of thinking was basically that if we apply a strong enough magnetic source (a field from a bar magnet) that any paramagnetic material would exhibit displacement. My understanding is that only a fraction of the paramagnetic material's electrons (those with the correct s... |
[
"Has anyone ever done a brain scan of someone who is about to die?"
] | [
false
] | What kind of brain activity is there as someone is dying? Does everything just turn off? Or is there like an explosion of activity first? | [
"I've made recordings from inside brain cells (neurons) of animals as they die.",
"But in a more general sense, we have a pretty good idea of what happens.",
"As oxygen levels drop, cells lose there ability to generate energy. In a brain cell, this means they loose the ability to separate electrical charge. Wha... | [
"Everything deepobedience wrote holds true, but if you want to get down to the nitty gritty details, things get quite \"exciting.\" (This is a bad pun. It will make sense if you keep reading.)",
"There are ion pumps on your neurons that help to maintain the negative charge deepobedience mentioned above. These ... | [
"It doesn't necessarily begin with lack of oxygen, but once you stop breathing and/or your heart stops beating (or otherwise delivering sufficient blood or sufficiently oxygenated blood to the brain), death typically involves a lack of oxygen to the brain at some point.",
"There are exceptions, of course: Certai... |
[
"Welding and arc-eye cures..."
] | [
false
] | [deleted] | [
"Yes, most of the information I could find when I wondered about this was concerning ",
"Photokeratitis",
", which appears to be a more serious condition.",
"I do remember reading something years ago, about how the proteins in the cells of the retina, which react to certain colours of light, can get \"locked\... | [
"What I think you're describing as \"arc-eye\" is ",
"phosphenes",
" from overstimulation of the retina. They are generally temporary (in which case looking at bright green can help by masking the phosphene for a while). Extreme cases (like if you actually did stare at a welding arc or a partially eclipsed Su... | [
"No worries -- it is a good understanding. But the time scale for the proteins to be reset is short -- at most a few seconds. Recovery of the retinal nerves takes longer, rather like persistent pain after a slap. ",
"BTW please dont be confused by ayellowbunny -- I have had a few encounters with his trolling o... |
[
"Why is the area around a wound hotter than an area without a wound?"
] | [
false
] | I got scratched by my cat, i was wondering why the area that got scratched is hotter than other parts of my body. | [
"The sensation of heat is caused by inflammation in response to your wound. Specifically, the ",
"heat comes from increased blood flow",
". While this is a local response in that it's around the wound rather than your whole body, it still involves peripheral areas responding and is only felt in the skin - so a... | [
"Increased blood flow to the skin surface will almost always increase the local temperature. Healing is a metabolically active process, as is fighting infection (the barrier has been breached after all). Mild wound flare is a normal part of post-surgical healing and it does not imply clinically significant infectio... | [
"Hey! You just rediscovered something known by the ancient Romans. Celsus listed the symptoms of inflammation: calor (heat), rubor (redness), dolor (pain), and tumor (swelling).",
"All of them are caused by blood rushing to the injury to get things fixed."
] |
[
"Env.Canada forecasts -51 C w/ windchill in Saskatoon, what happens to normal stuff at those temps?"
] | [
false
] | null | [
"I have experienced that windchill temperature firsthand while I was living in Fargo, North Dakota. I was moving at the time so I was doing a lot of packing into the back of my pick-up truck.",
"I can confirm just_commenting's statement firsthand. I remember that my normally flexible clothes hangers shattered und... | [
"http://www.reddit.com/r/askscience/comments/p1uem/if_actual_temp_is_above_freezing_but_windchill_is/",
"Or any of the other times this was asked in here.",
"The windchill is mostly important for how fast things cool down. The windchill temperature tells you that an object would cool down as fast as if it was i... | [
"The air temperature is generally what's important. Living things are affected by cooling in a really significant way - your body can't afford to be anywhere close to cold for very long - so the rate of cooling is very important when you are considering your own personal safety. As for objects like automobiles an... |
[
"Can any two physical objects be the same?"
] | [
false
] | Aside from position or any velocity an object may hold, can any two objects be in the same state? I believe we have to go down as far as we can to reduce an objects complexity. Is it even truly possible for two objects to the same, to have the same states at the exact same time? From what I know, this is not possible, ... | [
"When you get down to it, all fundamental objects are the same. All protons are the same. All neutrons are the same. All electrons are the same. Therefore, it is possible to have completely indistinguishable composite objects. Atoms can be indistinguishable. Molecules can be indistinguishable. Theoretically,... | [
"In principle, all subatomic particles are indistinguishable from all other subatomic particles within their cohort, so to speak. There's no measurement you can do to distinguish between one proton and another proton, because all the properties those particles have are identical among all the particles of that type... | [
"I think you might've missed the point. If two objects are indistinguishable, you can't tell the difference. ",
" can't tell the difference: A set of particles which can be distinguished (if only in principle) do not have the same thermodynamic properties as a set of particles that are indistinguishable. ",
"If... |
[
"how can pi be calculated out to millions of digits?"
] | [
false
] | I understand that pi is simply the circumference of a circle divided by its diameter, but wouldn't the circle and diameter have to have at least as many significant figures as that calculated? | [
"I suggest that you peruse ",
"this wikipedia article",
". It talks about the history of how pi used to be calculated before talking about the current methods used."
] | [
"Here's",
" the website where they discuss exactly how they calculated 5 trillion digits of pi. It includes descriptions of which algorithms they used."
] | [
"I think my favorite for elegance is ",
"Buffon's needle",
"."
] |
[
"Is there a paste or glue of some sort that applies magnetic properties towards which it is laid upon?"
] | [
false
] | If not could this "magnetic paste" be made, and if so how would you go about it? | [
"I did some Googling to see if anybody had thought to combine the properties of a ferrofluid and a bucket of paint, and as it turns out there's such a thing as ",
"magnetic paint",
"."
] | [
"If you're looking for a magnetic liquid, the closest thing that exists are ",
"ferrofluids",
". Ferrofluid is made by suspending tiny solid ferromagnets in a liquid. A challenge is that you don't want your tiny ferromagnets to clump, so if you tried to make a paste out of it, I suspect, though I'm not sure, th... | [
"Neat! Glad to know it exists. It seems limited, but I do kind of want some to play with..."
] |
[
"Do people with bigger heads have bigger brains or is there just more fluid around them?"
] | [
false
] | The Lindros brothers both had trouble with concussions in hockey and they have huge heads. | [
"Brain size can vary between people. However, the amount of surface area and connectivity is what matters. That's why the surface is so folded - to maximize surface area.",
"from ",
"Human Brain",
":",
"The adult human brain weighs on average about 3 lb (1.5 kg) with a size (volume) of around 1130 cubic cen... | [
"Surely intelligence, cognitive performance, etc. would more likely be a factor of the distance between the neurons rather than the number of neurons in a brain. Much like a computer - faster computing power doesn't typically involve making things bigger, but improving the density of the microchip, for example.",
... | [
"To continue on this, they have never been able to show any significant correlation between brain size and cognitive performance, autism or anything actually. And from my seminar-attending knowledge I don't think they know why, either."
] |
[
"Why do geothermal energy stations have pipes that make a loop?"
] | [
false
] | I am not talking about the ground loops.I saw a geothermal energy station on my way and it has long pipes overground that sometimes these loops that look like the letter "n". I wonder what is the point of that shape, is it for lowering the pressure or to cool down the steam or something else? | [
"Those kind of features are there to accommodate for temperature changes along the pipe. When metals get hot they expend. A 100 meter pipe can gain up to 10 cm in length transporting steam.",
"In order to accommodate for that thermal expansion engineers design those loops that can flex and absorb those changes in... | [
"I'd also add that the concept is often referred to as a \"dog leg\" and when transporting superheated steam the only limit to the expansion length of your pipe is the temperature of the steam."
] | [
"Thank you!! Been wondering about this for awhile."
] |
[
"Is a light year determined by the one traveling at the speed of light or the earth based observer?"
] | [
false
] | Basically, I wanted to figure out whose year is being taken into account when describing a light year. Is it how far light travels in one year from the perspective of someone on earth or as someone traveling at that speed? | [
"/u/Das_Mime",
" is correct, but I want to point out and then solve a weird \"paradox\" that arises from the speed of light being the same in any reference frame. ",
"Let's say Planet A and Planet B are separated by 1 light year as measured by someone on Planet A. Planet A and Planet B are not moving with respe... | [
"There is no such thing as someone traveling at the speed of light. You can't construct a reference frame for them. ",
"The speed of light is the same for all observers. Thus any observer watching a beam of light travel for a year will measure the same distance (provided that the observer stays in the same inerti... | [
"Are you asking this as a question, or just raising it as an incidental point?",
"Because the aging difference is a result of accelerations, not different velocities. (Also, neither the Earth nor the spaceship can be moving at light speed in your example.)"
] |
[
"What would happen if you were inside a swimmingpool which is dropped from an airplane?"
] | [
false
] | OK, so I had a really hard time figuring out a decent topic... Hope this will do. Imagine you are in a swimming pool (under the surface, with a oxygen mask). You drop this swimming pool from an airplane. Assume you stay in the water at all time, also assume that you do not hit any of the pool's edges when the pool hits... | [
"The impact as the pool hits the ground would crush you, moreso than if you had simply hit the ground yourself.",
"Shock waves travel through water even more strongly than through air (because water does not compress), and since you said the pool does not break that means there's no outlet for the energy of the s... | [
"This isn't my field of study, but couldn't the shock wave be dissipated more easily by splashing upwards from the top of the pool than by crushing your body?",
"The way I would go about analyzing this problem would be this: once the swimming pool lands, your body transitions from moving at the pool's terminal ve... | [
"Excellent reply. Thank you."
] |
[
"What happens if you receive the wrong blood type?"
] | [
false
] | null | [
"When your body receives an injection of a blood type, it will check the blood cells for certain antigens . When the detects an antigen (A, B, or AB blood type) which is not the same as it’s own blood type, it will treat the blood as an invading organism and attempt to kill it. If too much blood is infused, this ca... | [
"Your antibodies will react with the blood cells causing the RBCs to clump together and occlude your little blood vessels. Also you can have a traditional allergic reaction, like itching and fever ",
"Depending on the severity of the reaction and how much mismatched blood you received, you can suffer no real harm... | [
"So from the organism's standpoint, there's no real difference between, say, bacteria or viruses, and non-compatible blood? I know the mechanism miht be slightly different but, does that mean that blood rejection disease (whatever it's called properly) is more or less the same to an acute infection? In addition to ... |
[
"Why doesn't Chandrasekhar's limit apply to a supermassive star's (<50 solar masses) core when it super/hypernovas?"
] | [
false
] | [deleted] | [
"The outcome of a core collapse supernova largely depends on the mass of the progenitor. ",
"For a star less than 8 solar masses, it will not undergo a supernova.",
"For a star between 8 solar masses and 20 solar masses, it will undergo a core collapse supernova, producing a neutron star as the final remnant. "... | [
"The reason stars don't collapse normally despite their massive size is because the fusion that takes place at the core provides a counteractive force that prevents gravity from pulling all the mass to the center. ",
"The key difference in a supermassive star is that even when nickle and iron start to form at the... | [
"Neutron stars are squishy. The proto-neutron star is imploding, so it expands back out, which is the bounce. It strikes infalling material in a head-on collision at some considerable fraction of the speed of light, and a ",
" of momentum is transferred to the infalling material, driving the explosion. "
] |
[
"Why are the days on the two innermost planets so much longer than on all the other planets?"
] | [
false
] | According to the Mercurial day is equivalent to about 60 Earth days, and the Venusian day is equivalent to 243 Earth days. By comparison, the next longest day of any planet in the solar system is the Martian day, which is equivalent to about 1.025 Earth days. The days of all the other planets in the solar system are no... | [
"Well, the tidal effects of the Sun have Mercury in a 3:2 resonance, where it rotates on its axis 3 times for every 2 orbits. We expect that in general planets as close to stars as Mercury is will either be tidally locked or else have settled into spin-orbit resonances like this.",
"Venus' thick atmosphere likely... | [
"Right. Tidal effects from the Sun are very likely the reason for both Mercury and Venus. I don't think there's even any debate about Mercury. Venus is a little less clear cut, and you'll occasionally see giant impacts invoked to tilt Venus on its side and slow its rotation.",
"Venus' thick atmosphere likely made... | [
"Due to ",
"Tidal braking",
".",
"It's essentially the same reason we only see the same side of the moon. We used to see all sides of the moon as it's rotation was different to Earth's. But over time and due to tidal forces (essentially, the difference in forces on two sides of an object) it changed its rotat... |
[
"Do obese people have stronger bones?"
] | [
false
] | I am curious if obese people have stronger bones than normal weight individuals. I was thinking about bones and I remember reading how they suggest weight exercises in order to maintain strong bones (like lifting weights or doing resistance exercises) My question is do obese people have stronger bones or lower risk of ... | [
"Obesity isn't taken into account as a risk factor when calculating 10-yr risk of fracture using ",
"FRAX",
", while being underweight is. ",
"That being said, there are certainly papers out there linking obesity and osteoporosis. ",
"Fini et al",
" claim that BMI ≥ 40 is associated with increased risk o... | [
"Absolutely. Unfortunately, the joints cannot always handle the excessive forces which is why you hear of knee pain so often. It's recommended that an obese person avoid ",
" exercise until they drop down their weight to protect their joints. Once they lighten up though, they have incredible power for quite a ... | [
"Absolutely. Unfortunately, the joints cannot always handle the excessive forces which is why you hear of knee pain so often. It's recommended that an obese person avoid ",
" exercise until they drop down their weight to protect their joints. Once they lighten up though, they have incredible power for quite a ... |
[
"How much of the galaxy is 'inhabitable' by complex, intelligent life as we know it?"
] | [
false
] | To my knowledge, you can't get too close to the galactic center without dying a horrific death from radiation. Also, is there anything towards the outer edge of the galaxy that is likely to prevent complex life as we know it from existing? I guess the best way to put it is, is there a 'habitable zone' for the galaxy, l... | [
"The existence and boundaries of the 'galactic habitable zone' are still being debated, but yes, it is quite likely that there is one. You're correct about the galactic centre being full of radiation due to high star density, extreme levels of star formation, and a high supernova rate - but there's also the issue ... | [
"I guess the best way to put it is, is there a 'habitable zone' for the galaxy, like there is for a solar system?",
"For life as we know it, yes. But that isn't to say there won't be circumstances in which life could pop up in weird places. For example, Jupiter had moons which are generally considered outside the... | [
"Thanks for the great answer. It's much appreciated. "
] |
[
"What determines a greenhouse gas?"
] | [
false
] | [deleted] | [
"You can see the IR absorption spectrum of methane here ",
"https://webbook.nist.gov/cgi/cbook.cgi?ID=C74828&Type=IR-SPEC&Index=1",
". The peaks are at frequencies of light where the methane will absorb light. ",
"https://scilearn.sydney.edu.au/fychemistry/chem2401/q18_2012.pdf",
" this link explains which ... | [
"My first assumption was that the C-H bond was polar rather than the molecule as a whole but carbon and hydrogen have similar electronegativities so it is nonpolar.",
"Oh, the difference in electronegativity is absolutely big enough for C-H bonds to be polar. The polarity is not on the same level as for instance ... | [
"My first assumption was that the C-H bond was polar rather than the molecule as a whole but carbon and hydrogen have similar electronegativities so it is nonpolar.",
"Oh, the difference in electronegativity is absolutely big enough for C-H bonds to be polar. The polarity is not on the same level as for instance ... |
[
"Can anyone explain why gravity tends to organize things in discs?"
] | [
false
] | I know only very little about astronomy, but I've been wondering about this and thought maybe someone here can provide an explanation. From the (mostly) planar orbits of planets to Saturn's rings, to accretion discs around black holes and the more or less flat shapes of galaxies, it seems gravity has a tendency to orga... | [
"Wordy and handwavy: rotating things have an outward acceleration which then has to match gravity. And if it extends the other way, it is attracted to the average plane. (thusly a disk)",
"Less handwavy; in the coordinates x=r cos(ωt +φ), y=r sin(ωt+φ), z=z, there is an effective potential if you look at the forc... | [
"Agree with elitl, its angular momentum conservation, but here's a more detailed explanation. ",
"Picture a diffuse ball of gas that is much larger than the solar system (or planet or galaxy) with particles moving in mostly random directions, but has some relatively small net angular rotation in some random dire... | [
"So basically, satellite orbits in disk about planet due to planet rotation. Planets orbit about star due to star rotation. Stars orbit about galaxy due to galaxy rotation and so on, and so on? I was a little confused about why you made z constant since that was the question, but think I get it now."
] |
[
"If you flew to the edge of the Milky Way galaxy, what would you see peering out away from it? Darkness? Other galaxies?"
] | [
false
] | null | [
"Hi squarybuttholes thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the... | [
"'Astronomy'"
] | [
"Astronomy "
] |
[
"If body temperature is 98.6 °F, why don't I feel cold at room temperature?"
] | [
false
] | Or why do I sweat at 98.6 °F? | [
"There is a gradient of temperature from conduction with the air around you, and even without wind you are \"subjected\" to the environment temperature. But wind can carry away heat faster through convection, which makes you feel cooler. Don't think of it like there is a blanket or \"insulating layer\" that is keep... | [
"Your body generates heat when you burn calories. The heat is removed through evaporation. Above room temperature, your body has to sweat more to maintain 98.6"
] | [
"There's an insulating layer of air around your skin that keeps you feeling warm. Wind can blow this layer away and subject your skin to the environment temperature. Normally when a fan blows on your skin, you feel cooler; but I've heard in hot environments, you'll feel hotter! I haven't tried it, but it would defi... |
[
"Why does a can of compressed air get ice cold when used?"
] | [
false
] | null | [
"In the can, the compressed air is in the form of liquid at very high pressure. When you squeeze the trigger the pressure drops and the liquid boils into gas. That phase transition requires energy, which it pulls from the surrounding air (via the can). That causes a corresponding temperature drop of the can as heat... | [
"Most \"compressed air\" cans don't actually have air but rather some other fluid such as tetrafluoroethane, which will be liquid at reasonable pressures. ",
"https://en.wikipedia.org/wiki/Gas_duster",
"Keeping actual air liquid at room temperature would require a huge steel tank."
] | [
"Keeping actual air liquid at room temperature isn't really possible. Room temperature is way above air's critical temperature, so it can't exist as a regular liquid at room temperature, regardless of pressure. ",
"https://en.wikipedia.org/wiki/Critical_point_(thermodynamics)",
")",
"You could increase the pr... |
[
"Why is acetaminophen/codeine (e.g. Tylenol 3) the go-to painkiller for dental work?"
] | [
false
] | Background: I've got an abscessed tooth right now, and in addition to antibiotics, my dentist prescribed T3s for pain management. It suddenly occurred to me that across two countries, three cities, five dentists, and ~50 years, I have NEVER been given any other painkiller prescription. For non-dental surgery I've had a... | [
"I am in dental school and we were just talking about this today. Atleast in the USA, 10 or so years ago dentists were among the the highest over prescribers on narcotics aka opium derived pain killers such as hydrocodone. Dentists were an easy target for narcotic seekers, especially young dentists who just gradu... | [
"Tylenol/ acetaminophen is actually best when taken with caffeine. The caffeine enhances the effect of Tylenol on the pain receptors, and slows the neurotransmitter Cascade associated with the pain response.",
"In lay terms... Ibuprofen for inflammatory pain like infection, arthritis, some types of headaches, joi... | [
"Alternating acetaminophen and ibuprofen every three hours is commonly advised for dental pain at the dental school clinic in my area. I'd expect them to be on top of best practices. ",
"https://www.ada.org/resources/research/science-and-research-institute/oral-health-topics/oral-analgesics-for-acute-dental-pain"... |
[
"What does \"vehicle\" mean in the scientific medical literature?"
] | [
false
] | [deleted] | [
"A vehicle is the carrying gel/cream that contains the compound being researched. To make sure the control group gets as similar a treatment as possible, they get the gel/cream without the compound. ",
"The introduction of this article explains it quite well and talks about the confusion you have in medical liter... | [
"Is it like the carrier solution generally",
"Yes. The vehicle is the \"carrier system\" for the active pharmaceutical ingredient.",
"and in this context means people receiving the vehicle were given a \"placebo\"?",
"No. It means the people receiving the vehicle were given everything except the active compon... | [
"vehicle in this sense refers to \"the thing delivering the molecule we think is active\".",
"So for example if you want to see how doxycycline affects acne, you would design an experiment or a trial where one group would receive dox and the other would not. However, you need to formulate your drug in such a way ... |
[
"After smelling the same thing for a while, why are you no longer able to smell it?"
] | [
false
] | Asking because of an essential oil diffuser I have. It's nice smelling for a bit then I can't smell it anymore, no matter how strong the scent is. | [
"Sensory adaptation. Your brain decides that the particular sensory input is just a part of a neutral environment and focuses its attention to other things. Imagine trying to pay attention to a lecture if you're also constantly aware of your clothes on your skin, where your tongue is in your mouth, the sound of ele... | [
"This is why people with sensory processing disorders struggle. They are constantly distracted by many of the things you just mentioned."
] | [
"Sensory adaptation/overload. If an odor is particularly prevalent, the sensory organs are going to become over stimulated really really quickly. The neurons fire so quickly and sustainably that you get a refractory period where they no longer fire. If you watch people smelling durians (the fruit that smells like d... |
[
"How big would a building/dome/indoor park have to be in order to have it's own weather patterns?"
] | [
false
] | If it is at all possible, that is. | [
"It does in fact occur, there was a post recently about a ",
" (e: Nasa) building that has weather patterns from the humidity in the air.",
"e:",
"source"
] | [
"A small terrarium could go through evaporation - condensation cycles as it warms and cools through the day, and there would certainly be air currents associated, so it depends on what you're calling \"weather patterns.\""
] | [
"Boeing also is large enough to have weather patterns. They talked about it during the Future of Flight tour."
] |
[
"Elon Musk says Hydrogen is a pretty much a waste of time to help power automobiles. Is he wrong?"
] | [
false
] | Seeing that Hydrogen is the most abundant element in the universe, what can be done to advance Hydrogen Fuel Cell Technology?? Link to the article I read: Edit: Wow this discussion is great. Thanks so much for the answers so far. | [
"Hydrogen isn't necessarily a \"waste of time,\" but hydrogen-powered vehicles are certainly not viable today. Ironically, this same criticism has been levied against battery-powered electric vehicles that are produced by Musk's Tesla Motors.",
"Hydrogen is an ideal fuel, but there are problems with hydrogen pro... | [
"Hydrogen is the most abundant element in the universe, but it's present on Earth in the form of water. Water is the byproduct of the hydrogen combustion so you essentially have little to no energy that you can extract. ",
"The reason it shows promise is because it's a way of capturing and transporting emission f... | [
"It's important to note that Musk has a vested interest in the success of batteries as a technology.",
"His companies are focused on creating batteries.",
" ",
"http://www.bloomberg.com/profiles/companies/SCTY:US-solarcity-corp",
"http://www.bloomberg.com/profiles/companies/TSLA:US-tesla-motors-inc"
] |
[
"Do people with allergies get sick less often/less severely?"
] | [
false
] | Since an allergic reaction is the result of an immune system response to a harmless substance, I was wondering if this 'extra' activity would make an allergy sufferer less likely to fall ill from other foreign substances. On one hand, the immune system fights illness, so higher immune activity should = less overall sic... | [
"Generally no. Your body has several types of antibodies, or immunoglobulins which all have different structures and thus functions in the body. There are 5 types IgA, IgD, IgE, IgG and IgM. IgE deals with parasites and allergies. Thus having an allergic response will raise levels of IgE but none of the other immun... | [
"That's still really cool to think about, thanks for the response! "
] | [
"For allergies, the body thinks harmless antigens like peanuts are a threat, but otherwise operates normally. "
] |
[
"How do they measure the amount of calories in something?"
] | [
false
] | Is there an instrument you use? Formula? Some type of process? Is it possible to determine the amount of calories in something pretty easily using home items (without looking at the label), or does require a lot of instruments and/or a huge process? | [
"Here is the general definition of a Calorie: amount of energy needed to raise the temperature of 1 liter of water by 1 degree Celsius. Therefore, a Calorie is a basic unit that describes the amount of energy in the something you are interested in. There are a couple different ways to measure the amount of Calories... | [
"one gram is correct when you are talking about calories. However, I was speaking in Calories, which is the unit for nutritional energy. 1 Calorie = 1000 calories. When you do the conversion, 1 Calorie and 1 liter are used."
] | [
"Is there an instrument you use?",
"Calorimeter",
"Formula? ",
"It depends on the type of calorimeter. The most common one literally involves burning a small amount of the substance and seeing how much a known volume of water changes in temperature. From there you can calculate Calories per gram (energy per... |
[
"When I met my girlfriend, colors appeared suddenly highly saturated visually. The day we broke up, my vision was close to black/white. How is this possible?"
] | [
false
] | null | [
"We can't really comment on anecdotes / isolated incidents without resorting to speculation which we try to avoid."
] | [
"The reason I posted is that I found vague articles alluding to connections between depression and color vision. I am just looking for anybody with more complete information, rather than relying on google searches and pop science. ",
"https://www.nicabm.com/depression-the-connection-between-color-perception-and-m... | [
"Then please make a new post with a more general phrasing of your question like \"can mood affect color perception?\""
] |
[
"Why is silver anti-microbial?"
] | [
false
] | null | [
"Medical Student who majored in Microbiology and Molecular Biology here:\nSilver has been known for hundreds of years as an antimicrobial. It is thought that since silver has a propensity to interact with the thiol groups, ( -SH groups), it denatures proteins by disrupting these bonds. Proteins without proper disul... | [
"I'm not super confident in the explaination I'm about to give as I'm a physical chemist, not a biochemist. The way silver interacts with large organic compounds is not my specalty.",
"Most antimicrobial silvers are silver nanoparticals, sometimes called colloidal silver. These are small crystals of metallic Ag",... | [
"Also, the cells with which we touch the silver (our epithelia) are already dead."
] |
[
"Is there a Tuberculosis Pandemic?"
] | [
false
] | Hey everyone! I came across some disturbing figures. In 2019, an estimated 1.42 million people died of TB (TBFacts. Org). And now, approximately 1.8 billion people have TB (most are latent). Would TB be considered a pandemic? | [
"TB probably should be considered a pandemic. The reason it isn't is probably more political. It doesn't greatly affect wealthy nations. And in the low to moderate wealth countries it does affect, it tends to affect the poorest people. It's also not immediately going to overwhelm the hospital systems in a major way... | [
"The other thing about TB is that we have a cure. We know how to treat it, with 6-9 months of specialized antibiotics.",
"Mtb has been showing increasing levels of antibiotic resistance over the past several decades",
", so while we may have approaches for treating, they don't always work (especially in endemic... | [
"TB absolutely should be considered pandemic but some for odd reason WHO and CDC only seem to classify it as epidemic. I can't help but wonder if it would be treated differently if the majority of cases were in Europe and the US instead of in developing countries."
] |
[
"How quickly does our digestive system process fats?"
] | [
false
] | Basically what the title says. I have noticed that I often have to poop half an hour after eating. I know that food isn't processed that fast, and I don't think that I eat that regularly for it to be from a few days ago. It tends to happen mostly after a large meal, such as from a fast food joint. Is it possible that t... | [
"Thanks! Both interesting links. I wonder why the difference in transit time is so affected by gender?"
] | [
"Thanks! Both interesting links. I wonder why the difference in transit time is so affected by gender?"
] | [
"Fat actually slows your digestion! That’s why you feel fuller longer after a meal with fat in it. Many diets now use eating fats as a way to lose weight (but be careful not to eat too much fat, there’s a lot of calories in it and saturated fat and cholesterol might not be the best for you). ",
"The other thing t... |
[
"How do F1 tires offer enough grip to cars when they are completely streamlined?"
] | [
false
] | Perhaps streamlined isn't the right word but how does such a smooth tire keep the car stable on the really acute turns? Does it have anything to do with the surface of the track? | [
"More surface area of the tire that comes in contact with the road exponentially increases traction, except in adverse weather conditions. Treads are only used to give water an \"out\" per se so as to prevent hydro planing. Usually formula one cars do not have to deal with adverse weather conditions, however, when ... | [
"The front wing also produces significant downforce. The balance between front and rear downforce directly affects the car's cornering behaviour. This is referred to as either 'over-steer' or 'under-steer'. Sometimes the front wing angle is adjusted in the pit stops. "
] | [
"The front wing also produces significant downforce. The balance between front and rear downforce directly affects the car's cornering behaviour. This is referred to as either 'over-steer' or 'under-steer'. Sometimes the front wing angle is adjusted in the pit stops. "
] |
[
"Besides encryption and improving the FFT, what applications would an efficient integer factorization algorithm have?"
] | [
false
] | null | [
"According to the ",
"discussion here",
", not a lot seems to happen from a complexity standpoint."
] | [
"A fast Fourier transform (FFT) algorithm computes the discrete Fourier transform (DFT) of a sequence, or its inverse. A FFT rapidly computes such transformations by factorizing the DFT matrix into a product of sparse (mostly zero) factors. As a result, it manages to reduce the complexity of computing the DFT from ... | [
"A fast Fourier transform (FFT) algorithm computes the discrete Fourier transform (DFT) of a sequence, or its inverse. A FFT rapidly computes such transformations by factorizing the DFT matrix into a product of sparse (mostly zero) factors. As a result, it manages to reduce the complexity of computing the DFT from ... |
[
"Do plants have immune systems?"
] | [
false
] | null | [
"Yes, its the soil microbiome. Their \"stomach\" is underground, mixed in the plant roots, with soil nutrients, and a symbiotic relationship with Mycorrhizal fungi. This is why healthy soil makes healthy plants and reduces your need for fertilizers, herbicides, and pesticides. Crop rotations, biodiversity, and orga... | [
"You might be interested in these previous responses to similar questions:",
"https://www.reddit.com/r/askscience/comments/iqfol/do_plants_have_immune_systems/",
"https://www.reddit.com/r/askscience/comments/gc5lm/do_plants_have_an_adaptive_immune_system_similar/",
"https://www.reddit.com/r/askscience/comment... | [
"CRISPR was ",
"originally discovered in ",
", and shortly thereafter in ",
"other bacteria",
" and ",
"archaea",
". And as it's ",
"actually part of the adaptive antiviral immune system available to prokaryotic cells",
", I don't believe it was ever thought to exist in eukaryotes (like plants)."
] |
[
"What is Meant by Changing Particle State Remotely?"
] | [
false
] | Apologies for the very poor title but I don't know how else to describe my question. I read an article on an inflight magazine about the advancement of microprocessor technology where it very superficially made the following statement, which I cannot begin to understand: "Scientists have had a breakthrough where the st... | [
"They are probably referring to the quantum teleportation experiment. You have two entangled particles, one on earth and one on the satellite, and then you do a joint measurement on earth with your entangled particle and the particle you want to \"teleport\". ",
"After measurement, the previously entangled partic... | [
"Basically, they created a pair of entangled particles, separated them by a large distance, and thus were able to modify the state of one by modifying the state of the other.",
"Best one line expansion I can give you."
] | [
"It's a poor choice of words to describe the collapse of state of a pair of entangled particles.",
"In actuality, nothing really \"changes\" at all. Two measurements are made and are found to be correlated, and with further measurements it can be shown that the values cannot have been set beforehand, but - and th... |
[
"Do planes travel quicker travelling west?"
] | [
false
] | So this may seem like a retarded question, but i was wondering whether or not planes travelled faster going west (as opposed to east) because the world is spinning in their favour or is the atmosphere held in the same acceleration frame as the earth? | [
"The atmosphere is, roughly, speaking, rotating with the earth. Planes travelling west do have the advantage of the Coriolis force, which means that they experience a slight upwards force while travelling west. This is not a huge effect, however.",
"In fact, in the Northern hemisphere, travelling East is usuall... | [
"Unrelated, but I love how your tag is just \"Lasers\". Badass. "
] | [
"Right, my point was the time it takes to travel is much more affected by prevailing air currents than by the direct effect of the Coriolis force. ",
"So in general, travelling east to west will be slower than travelling west to east."
] |
[
"Is there anything really special about our sun that is rare among the universe?"
] | [
false
] | There are systems with multiple stars, red and blue giants that would consume our sun for a breakfast, stars that die and reborn every couple of years and so on. Is there anything that set our star apart from the others like the ones mentioned above? Anything that we can use to make aliens jealous? | [
"Well, the stars that you mention are less common than our little yellow dwarf star, which is a pretty common size (in general: the smaller the main sequence star, the more of them there are and the longer they live). It's also high-medium in metal, which makes sense given its robust planetary system, so that make ... | [
"Yes.",
"There is 1 aspect of the sun that is rare and that is solar variability. Our sun is unusually stable in terms of it's output and this has actually had an impact on our search for exoplanets. ",
"Cool Worlds has done a video on it",
", and also ",
"how this affected the Kepler Mission search for exo... | [
"Not really. Our star is part of the \"main sequence\" i.e. pretty typical. Though, technically, binary systems are more common than single star systems, so ours is slightly unusual in that respect. But single star systems are still pretty common."
] |
[
"Within your field, what goal are you trying to achieve with your research?"
] | [
false
] | I know it's a broad question but I would love to hear more about the things you are working on. The panelists are very helpful when answering the questions of us laymen, but we would definitely like to learn more about you. It can be the project you're working on now, or a goal that you have set to complete before the... | [
"I'm building a model that will reconstruct the exact amount of radiation given to a tumor during external beam radiation therapy for cancer. ",
"Currently, we have very precise plans based on CT scanning, but you can never precisely measure how much dose was given to the tumor on any given day (mostly due to un... | [
"This has already been kind of posted: ",
"http://www.reddit.com/r/askscience/comments/h5uhz/what_is_the_holy_grail_of_your_field_what_is/",
"Here is what I said:",
"The central dogma of biology states that information flows from DNA->RNA-> protein. RNA has always been the secondary messenger. However, due to... | [
"Thanks for being curious. The panelists probably have heard me talking about this one time too many already ;) ",
"I'm working on ",
"synthetic ion channels",
" right now, and the long term goal here is being able to do stochastic sensing and ",
"ionic computing",
". ",
" we can get there (and that's... |
[
"Why is it recommended to avoid lying down after taking iron supplements?"
] | [
false
] | null | [
"Some medicines - such as iron supplements - can cause ulceration of the oesophagus if they do not pass cleanly into the stomach. ",
"Lying down after taking an iron supplement can increase the chance of this occurring so it is advised against for a period of time."
] | [
"Certain pills can cause severe esophageal irritation even to the point of an ulcer if they get lodged there instead of moving to the stomach. So things like iron, doxycycline, bisphosphonates (osteoporosis treatment) can all do it, so it is generally good practice to take water to flush it down and let gravity hel... | [
"Why not write that on the label? Also, does that means your may want to push it down with water or food, just in case, to ensure it is fully swallowed?",
"\"Please stay upright.\" does not convey the message. I would assume it's because it may have something to do with equilibrium, headache or blood pressure. No... |
[
"If we could swap orbits of Mars and Venus, which planet would be hotter?"
] | [
false
] | I am trying to understand: | [
"This is actually a really difficult question. Let's talk for a moment about \"Equilibrium Temperature\".",
"The Equilibrium Temperature is how hot you'd expect a planet/moon to be if it's only absorbing sunlight, then re-radiating infrared as a perfect blackbody. This estimate is easy to do, but only works well ... | [
"The answer to your first question can be seen in the temperature difference between Venus and Mercury. Venus (according to wikipedia) has a mean surface temperature of 737K, Mercury has a mean surface temperature of about 340k and maxes out around 700k (same source). Mercury is closer to the sun, but has much le... | [
"For extra fun times, we could then start to think about how the changes will affect rock cycling over geological timescales."
] |
[
"Evolution of bird head spikes?"
] | [
false
] | [deleted] | [
"In some species that don't have crests, if you add a fake crest to some males females prefer those. This is called sensory bias. "
] | [
"Probably based on mating selection, that is, other birds think they're prettier so prefer them as mates."
] | [
"Same goes for tail length in some situations. You can add a fake tail that is absurdly bigger than anything every found in nature, but the male will still get more females than those will normal tails. "
] |
[
"How much faster would the earth have to be spinning for large objects (us) to fly off?"
] | [
false
] | null | [
"The 'centrifugal acceleration' would have to be at least equal to the gravitational acceleration, so:",
"w",
"r = 9.8 ms",
"\nWhere w is the angular velocity (rad*s",
") and r is the radius of the earth (6.4 * 10",
" m)",
"Solving for w gives: w = 0.00124 rad*s",
"\nSo the earth would have to make at... | [
"And what this speed does it put you (and everything at the equator really), in LEO. The atmosphere will rather quickly escape the earth too."
] | [
"Now here's the part that will spin your head: imagine intelligent life evolving on such a planet, where the spin is just fast enough, or maybe just a little faster, so that at the equator and a region around it, the centripetal acceleration matches gravitational acceleration.",
"But that's only around the equato... |
[
"Given enough pressure, could we have water in the form of ice at arbitrary high temperatures?"
] | [
false
] | Knowing that reduced pressure will allow water to boil at lower than 100c temperature, is the inverse true? Can we have a 200c block of ice? | [
"I have a couple of follow up questions:",
"What would ice at 350 degrees Celsius be like? Would act like normal ice (aside from it boiling my drinks instead of making them nice and cold)",
"What is the critical point between vapor and liquid?",
"What occurs at the triple point at 0 degrees Celsius?"
] | [
"I have a couple of follow up questions:",
"What would ice at 350 degrees Celsius be like? Would act like normal ice (aside from it boiling my drinks instead of making them nice and cold)",
"What is the critical point between vapor and liquid?",
"What occurs at the triple point at 0 degrees Celsius?"
] | [
"Thank you :) ",
"Weird that pressure has to ramp up so dramatically in order to \"contain\" an increase of temperature that doesn't seem quite as spectacular ( from 0c at 100000pa to 200c at 2 500 000 000pa). Why is this ? Is this more related to the scales we use to measure things ?"
] |
[
"What is the best evidence of human caused global climate change?"
] | [
false
] | I understand some global change as a possible natural cycle and micro/local change is often caused by humans (cities, changing waterways etc.) but what is the empirical basis for global change caused by humans? | [
"Carbon dioxide can trap heat. You can demonstrate that with a box, a CO2 canister, a light, and a thermometer. We have measured a drastic rise in CO2 concentration in the atmosphere, along with a rise in temperature. We do things that release CO2 into the atmosphere, like burning fossil fuels."
] | [
"What would you accept as evidence?"
] | [
"Honestly, the answer to this question is ",
". I've dealt with similar questions before here on reddit, and in the course of them, I discovered ",
"this",
" site, written by an actual physicist (though not a climatologist) with a history of writing about science for public consumption. It covers the topic mo... |
[
"Is there such a thing as a cholesterol processing disorder? Where cholesterol is created and floats around the body without being properly used?"
] | [
false
] | Let me start with, I apologize for my grammar, I've always been one for run on sentences, and terrible writing skills like that Ok, I've had a randomish idea and I would like someone that knows way more than me about these things tell me I'm right or a complete moron, or any combination of the two I have ADHD, medicate... | [
"Anything is possible. Is it probable, no. ",
"If you have a problem processing cholesterol into estrogen/test/vitD you’ll likely have other issues with things like puberty and secondary sexual characteristics which are the results of testosterone/estrogen. ",
"It doesn’t sound to me like that is the case as yo... | [
"That suggests to me that your cholesterol is high - but not familial cholesterol high. Usually those cases are slap you in the face high. ",
"Diet and weight loss are your first step before pharmacologic management."
] | [
"Thank you, yeah it's not astronomical high, everything that's off is off by a couple points in either direction, at least with the most recent bloodwork"
] |
[
"Can lamps be used at home to compensate for not enough sun reaching a sun loving plant?"
] | [
false
] | I know that the very simple answer to my question is yes, but bear with me as I try to be more specific As you can see from that my Bougainvillea mini tree isn't doing so well and it is probably because it is not getting enough sun-light in my kinda-dim balcony So, my question is this, can I help the plant flourish usi... | [
"You have already answered your science question.",
"For the practical advice you seek try ",
"/r/gardening",
" ."
] | [
"There are full-spectrum bulbs available that mimic sunlight. They're not that expensive. ",
"http://www.amazon.com/b?ie=UTF8&node=328870011"
] | [
"Most full spectrum bulbs do not give off UV.",
"http://www.fullspectrumsolutions.com/definition_of_full_spectrum_light.shtml",
"http://www.gelighting.com/na/business_lighting/faqs/health.htm"
] |
[
"When we hear about small populations of animals making a comeback or growing wildly in a new habitat, isn't there a huge problem with their limited genetics, similar to the problem of mutations in offspring from incest?"
] | [
false
] | For example, a recent post "TIL that 24 rabbits introduced to Australia in 1859 led to a population of 10 BILLION by 1920". Or populations that are severely endangered that make a comeback. | [
"I'm not sure what you expect for an answer here. \"No, the rabbits aren't real, you're right, the theory says it can't happen?\" Obviously, the rabbits did happen, so the answer is that the inbreeding ",
" cause a huge problem.",
"Does that mean that inbreeding is not a problem? Not at all. Inbreeding leads ... | [
"Interesting. Reference? I've seen ",
"rabbit manuals",
" that say rabbits can tolerate \"The rabbit can support a slow and gradual increase in inbreeding, hut research suggests that mating programmes for small populations should minimize its extent and rate of increase among the stock\", which is much like o... | [
"Interesting. Reference? I've seen ",
"rabbit manuals",
" that say rabbits can tolerate \"The rabbit can support a slow and gradual increase in inbreeding, hut research suggests that mating programmes for small populations should minimize its extent and rate of increase among the stock\", which is much like o... |
[
"Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science"
] | [
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! ... | [
"So we all assume life can only exist on planets. Is there any reasonable theoretical possibility that life could exist in a \"floating\" mass of liquid or gas? Say the mass was more or less a consistent distance to a sun."
] | [
"It's rather unlikely. Outside of the atmospheres of planets (or of moons like Titan), the ambient pressure is extremely low, such that water and most other substances cannot exist in liquid form. For reference, the densities of dense molecular clouds (the large objects in which stars form) are generally less than ... | [
"The size of a black hole is usually defined to by it's event horizon (the distance from the center that within which light can't escape), not by the \"size\" of the singularity inside of the event horizon. You've correctly noticed that asking about the size of a dimensionless object isn't very meaningful. ",
"No... |
[
"Why is it necessary that I completely finish my antibiotics when the symptoms abate halfway through the prescription?"
] | [
false
] | null | [
"When symptoms go away, it is not necessarily indicative that all of the bacteria causing the infection have been killed or are once again held in check by your commensal flora. If the prescription is halted immediately after symptoms disappear, it's still possible for the infection to come back. Essentially, finis... | [
"Perctly agree, I would just add that many antibiotics don't kill the bacterias, they just avoid bacterias to divide (they are called bacteriostatic). So you have the impression to get better and when you stop the antibiotic... BOOM they all divide at once starting again for a full rage invasion.",
"Let your body... | [
"It's basically survival of the fittest. ",
"Making up numbers, just to illustrate:",
"You have 1 million bad bacteria in you. They are constantly multiplying. Let's say their number increases by a quarter again every day. Your immune system is killing them at 200 000 per day - at this rate, they will continue ... |
[
"How is it possible that 2 protons give you gas (Helium) but 3 suddenly makes it metal (Lithium)?"
] | [
false
] | Kind of titlegore, but I don't quite understand, what makes for example Lithium metal? If I were able to modify an atom core by adding/removing protons and I would take an atom of Helium, add another proton, would I suddenly get an atom of Lithium? I'm very interested in what gives elements their properties on atomic l... | [
"No, it's not ",
" a metal. It's technically a non-metal. It does not bond to anything, even itself, and therefore cannot participate in electronic conduction. At room temperature it is a non-conductive gas. At extremely cold temperatures you can find it as a non-conductive liquid, and that's about it. There... | [
"No, no one classifies something as a metal if the only conditions in which it could possibly exist are completely hypothetical and never experimentally verified. It's a noble gas, pure and simple. If you're going to classify things only by the most improbable state that might hypothetically exist, then you bette... | [
"For two nuclei to interact, they'd have to come in contact: this simply doesn't happen at ambient temperatures (you need millions of degrees and immense pressure; or to manually shoot nuclei at each other). That's why the only nuclear interactions we see in everyday life are spontaneous emission of radiation caus... |
[
"What effects do muscle relaxants have on the heart, since it's also a muscle?"
] | [
false
] | null | [
"The short answer is: none!\nThe better answer is: \nNeuromuscular blocking drugs like atracurium, rocuronium, mivacurium etc act on the neuromuscular junction. They antagonise nicotinic acetylcholine receptors and this cause an inability to pass inputs from nerve to muscle cells (as opposed to suxamethonium which ... | [
"Hopefully someone with detailed knowledge will chip in, but we have two basic types of muscle. Skeletal muscle, that is under voluntary control, and smooth muscle that is not. The former makes up you biceps and hamstrings and all the big muscles you know and tiny ones that only have names in anatomy text books. Th... | [
"That's pretty much it. Remember the diaphragm is voluntary muscle, and without nerve input stops working. The heart has an intrinsic rate of beating that doesn't require any nerve input to persist. So these muscle relaxants will kill you by stopping your breathing. That's why they're used in surgery to relax muscl... |
[
"How did we find out that COVID-19 was a new disease so quickly?"
] | [
false
] | With the symptoms being so close to the common cold or a flu, wouldn't most doctors have simply assumed that the first patients were suffering from one of those instead? What made us suspect it was a new virus, and not an existing one? | [
"The symptoms were nothing like the cold or flu, thousands were dying in Asia. Virus samples are frequently DNA sequenced worldwide as part of a monitoring program. A new sequence was correlated with high death rates or need for ventilators. ",
"A better question is once we knew for certain we had a new and dead... | [
"Just going to post this again:",
"Timeline of events based loosely off of Wikipedia with additional sources added for a more complete picture",
"first cases of COVID roll in to hospitals in December, possibly as early as late November according to retrospective analysis and sampling old biopsies. (For complete... | [
"From what I remembered, protocols were put in place to limit spread. However, protocols were based upon the SARS outbreak, which could only be spread by symptomatic people (e.g. who were detectable by fever, severe cough, etc). COVID appeared to be able to be spread from relatively asymptomatic individuals (e.g. m... |
[
"How do we create suction (like for a straw)?"
] | [
false
] | I know it would be a decrease in air pressure, but what is causing that? It can't be the lungs or you would be at constant risk of inhaling your drink, right? (Plus you can drink while breathing out.) Is it the mouth? Yet I can make the motions with a straw in my mouth and not suck in any liquid. Is it something I over... | [
"It’s important to know that liquid doesn’t get “pulled” through a straw, but rather the ambient pressure ",
" the liquid into you mouth. This is because when the water is just sitting there with the straw in it, it’s not that there are ",
" forces acting on the liquid, but rather the air pressure acting on the... | [
"Your tongue. Basically you depress your tongue, creating more space inside your mouth. Because you have not allowed more air to enter that space, the liquid automatically gets sucked up to account for the negative pressure."
] | [
"Close your mouth, and get all the air our of your mouth. Your tongue should be rested along both the bottom and roof of your mouth. Now without allowing any air from your lungs or your sinus/nose, try to pull your tongue down, off the roof of your mouth. Don’t just pull your tongue back, but actually try to create... |
[
"How is the EM-Drive different from a reverse solar sail?"
] | [
false
] | null | [
"For sure, if you just shine a laser one way then your spacecraft is propelled the other way.",
"The emdrive is a sealed cavity though. The RF waves just resonate inside the cavity and are not directed out the back end of the spacecraft.",
"I do not believe they have either their theory or experiments correct t... | [
"let me rephrase: Why does emmiting elektromagnetic waves behind your spacecraft not generate thrust?"
] | [
"let me rephrase: Why does emmiting elektromagnetic waves behind your spacecraft not generate thrust?"
] |
[
"Does a lithium battery on it's own (not plugged in to anything) produce electromagnetic waves?"
] | [
false
] | If I had a normal cellphone battery on it's own would it produce any sort of electromagnetic field? | [
"I assume you mean aside from black-body radiation that everything with a non-zero temperature emits. You and a lithium battery, simply by being about 20-30 degrees celsius, are always emitting infrared light."
] | [
"\"If the battery is not connected to anything there will be no meaningful motion of charges, so there will be no electromagnetic waves produced.\" Why again after sometime when the battery hasn't been connected to anything it happens to discharge? And while charges were not at any motion. "
] | [
"\"If the battery is not connected to anything there will be no meaningful motion of charges, so there will be no electromagnetic waves produced.\" Why again after sometime when the battery hasn't been connected to anything it happens to discharge? And while charges were not at any motion. "
] |
[
"Why do bubbles tend to be roughly spherical?"
] | [
false
] | null | [
"For a given volume, a sphere is the shape with minimum surface area.",
"A bubble is made of two things, air inside, and a film outside. The film's surface tension causes it to be as small as possible, while the air resists being pressed into a smaller shape. The best compromise is a sphere.",
"Imagine another ... | [
"Surface tension forces try to minimize the surface area of a bubble of a given volume.",
"The 3D shape that has the most efficient ratio of surface area to volume is the sphere."
] | [
"/r/asshole"
] |
[
"Why does ice sometimes stick to my skin?"
] | [
false
] | null | [
"Because moisture on your skin freezes when you touch the ice or because touching the ice you momentarily melt the ice but then the ice cools your skin sufficiently that the ice just melted can refreeze."
] | [
"No, although technically the ice is stuck to your finger by ice, which itself is stuck together by hydrogen bonds, I think it's just friction. So yes, and no, it depends what you mean. It's like saying glue is stuck to something by covalent bonds, yeah, but no. "
] | [
"Right, and it doesn't happen every time, because you need the perfect balance of a little bit of moisture, skin that's cool, and mostly dry, and super cold ice"
] |
[
"I'm 40 yrs old and just found out that chickens lay eggs regardless of fertilization. Why? From an evolutionary perspective, that seems like a huge waste of energy."
] | [
false
] | As far as the unfertilized egg thing goes, it's just one of those things I never thought about it before. | [
"This question has kind of the same answer as ",
"this one",
" from earlier today. Many domesticated species behave in ways that are radically different from what would be advantageous in the wild. Remember that natural selection is only one mechanism that can drive evolution—there is also artificial selection.... | [
"As someone who raises a backyard flock, I want to add that chickens do and will eat their own eggs, shells and all, if they are inclined or hungry. These are called ",
"Trophic Eggs",
", and the phenomena is common in several other animal species. \nEggs are pure protein, calcium, etc. so they can potentially... | [
"This is common in many mammal species. Mothers eat whatever they can salvage out of the birth process to get nutrition, since the energetic costs of lactation are even higher than the cost of making the babies."
] |
[
"I there any evidence that Essential Oils have any beneficial effects on the human body?"
] | [
false
] | null | [
"We don't offer medical advice on ",
"/r/AskScience",
", including discussing health benefits of products. We also don't debunk unscientific claims, because we're not here to argue about things with no scientific evidence behind them. If you have a specific question about how something like a certain fragrance ... | [
"I'll delete it as soon as I can; I'm on mobile. If you can delete it sooner, that would be great for me. ",
"I apologize. I'm not entirely sure how to check guidelines on mobile, which is how I usually use Reddit. Again, sorry, I didn't mean to break your rules."
] | [
"We had already removed the post, so no worries there. If the wiki is inaccessible to you, do you have the ability to check the sidebar in the app you use? This is by no means a problem unique to you, and we'd really like to make sure our guidelines are available to our readers."
] |
[
"Star size?"
] | [
false
] | [deleted] | [
"Short answer: A star wants to collapse on itself due to gravity. What prevents this is photon pressure from the nuclear reactions in the core of the star. The size is thus determined by balancing the force of gravity pulling inward with the pressure from the photons escaping outward.",
"To get a bit more detail ... | [
"I would be careful with the language you are using to describe this object. While it is true that less massive stars are unable to fuse heavier elements, any star above about 8 solar masses (depending on it's heavy element abundance - read heavy element as anything larger than helium, astronomers are crazy!) is fu... | [
"They will, in fact, have very similar compositions as all stars do. The main differences here are the initial mass and the stage of their lifespan that each star is in.",
"Check ",
"this",
" out. Read 'size' as increasing from bottom left to top right, and the spectral type indicates what the initial mass ... |
[
"How do sailboats convert wind energy to travel faster than the prevailing wind?"
] | [
false
] | For example, in the Americas Cup last night, wind speeds of around 20 kts allowed the boats to travel at 40+ kts? TY in advance. | [
"It is easy to understand how the wind produces a force against the sail. When the boat is sailing with the wind, the faster the boat moves, the less force on the sail. However, if the ship sails at an 90 degree angle to the wind, it is also easy to imagine that the force reduction is negligible while the ship mov... | [
"Ignoring Bernoulli for this discussion we can think of acceleration is a change in velocity. A curved sail changes the direction of the incoming wind and produces a change in the velocity of the wind. To counteract that change the boat must gain an acceleration in the opposite direction. If you work out the for... | [
"More to the point, the boats can only gain that speed when reaching across the wind, not in a direct downwind run, that way the apparent wind velocity from the boats perspective doesn't change with increasing speed. "
] |
[
"Why do organisms larger than insects not go through a metamorphosis? What caused certain insect species to evolve to have a metamorphic process in their life cycle?"
] | [
false
] | null | [
"Many do! For example, within the vertebrates, (almost) all amphibians and a considerable number of fish go through a process of metamorphosis (i.e. tadpoles becoming frogs), all of which is controlled by thyroid hormones. But yeah, sure, they don't go through something called holometabolous metamorphosis, unlike i... | [
"How do insects possibly survive the cacoon/pupa stage that lasts for, I don't know, days/weeks? Aren't they ridiculously vulnerable? "
] | [
"They certainly are vulnerable, and insect species have evolved various strategies to cope with this fact. Lots of insects including many moths, flies, and beetles burrow underground to pupate. In fact, larvae are generally not much better suited to evade or fight off predators than pupae are. For this reason, many... |
[
"Why do black teas have more caffeine that green teas?"
] | [
false
] | null | [
"This website",
" gives a very good explanation, as does the ",
"wikipedia page on caffeine",
" but for the TL;DR version:",
"Studies have shown that it is actually a myth that black teas have more caffeine, as caffeine content varies more between individual teas than across broad categories. Caffeine con... | [
"Ha ha, no not at all! How did you so thoroughly misunderstand that post but still feel so confident that you thought you could write a tl;dr?"
] | [
"Ha ha, no not at all! How did you so thoroughly misunderstand that post but still feel so confident that you thought you could write a tl;dr?"
] |
[
"Why do sycamore trees lose their bark?"
] | [
false
] | I know that sycamores lose their bark when spring and summer roll around, but why does it happen? | [
"Your are American, yes? So what you think of as a \"sycamore\" is ",
" which like all Plane trees sheds its outer layer of bark as the layer below grows.",
"I love, love, love that there is a Plane tree that looks like a maple, ",
" and a maple that looks like a Plane tree (and is what we call \"sycamore\" i... | [
"An American sycamore tree can often be easily distinguished from other trees by its mottled exfoliating bark which flakes off in great irregular masses",
", leaving the surface mottled, and greenish-white, gray and brown. The bark of all trees has to yield to a growing trunk by stretching, splitting, or infillin... | [
"Well thank you very much. That definitely helps. TIL. ",
"Now the question is, why does it grow another layer underneath while other trees will just grow outward and their bark will expand with their layers?",
"Please correct me if I'm wrong on this. I'm just trying to get the information straight for myself."... |
[
"If two identical twin men, both had sex with the same woman, and one had gotten her pregnant, would a test be able to tell which man one the father?"
] | [
false
] | null | [
"Without going into how much this would cost:",
"Say during development gene X in an identical twin acquired a unique point mutation (a SNP). During crossing over, there would be a chance for the child to aquire this same change in the genetic code. Obviously this would be a hard thing to assess because you first... | [
"This has actually happened in 2007",
" and the father couldn't be determined.",
"A quote from the story",
"It's probable that no one-the Millers or the courts-will ever know who the true father really is. \"With identical twins, even if you sequence their whole genome you wouldn't find a difference...they're... | [
"As different as any two siblings with the same father would be"
] |
[
"Liquids can't actually be incompressible, right?"
] | [
false
] | I've heard that you can't compress a liquid, but that can't be correct. At the very least, it's got to have enough "give" so that its molecules can vibrate according to its temperature, right? So, as you compress a liquid, what actually happens? Does it cool down as its molecules become constrained? Eventually, I guess... | [
"As you go down, you'd eventually hit ice instead of rock. If a planet with Earth-like gravity had a sufficiently deep ocean, any parts of the ocean over 60km deep would be frozen solid by pressure rather than cold, with the molecules jammed so tightly together by the pressure that they line up in a solid crystal l... | [
"As you go down, you'd eventually hit ice instead of rock. If a planet with Earth-like gravity had a sufficiently deep ocean, any parts of the ocean over 60km deep would be frozen solid by pressure rather than cold, with the molecules jammed so tightly together by the pressure that they line up in a solid crystal l... | [
"Correct, they are just much harder to compress than gas. At the bottom of the ocean the water is compressed by a few percent compared to the top. Typically compressing a liquid enough turns it into a solid, water is a little weird in that regular ice is less dense, so if you compress water enough it'll form a less... |
[
"Are there any animals that are capable of living without sleep?"
] | [
false
] | null | [
"To answer this question fully, we would first have to know about every single organism on earth, and we probably don't. Second we would have to have a good way of measuring sleep, something we currently do not have. Once we have those things we can figure it out, but at the moment it doesn't seem like there is any... | [
"Coral is an animal. Does coral sleep? "
] | [
"I know at least some jellyfish go into states of inactivity at night, so maybe other cnidarians do too. I don't think sponges sleep, though."
] |
[
"AskScience AMA Series: I'm Alexis Kaushansky, a Principal Investigator at the Center for Infectious Disease Research in Seattle, WA. I research malaria and the interactions between host and pathogens. I’m excited to talk to you about it. AMA!"
] | [
false
] | Hello Reddit! My name is Alexis Kaushansky and I serve as a principal investigator at the Center for Infectious Disease Research. My research studies the interactions between humans and pathogens, with a particular focus on malaria. The malaria parasite and other infectious diseases that burden the world cannot survive... | [
"Does eradication/extinction of Anopheles mosquito (IF we could do that) has potential to cause negative effects on the ecosystem?"
] | [
"I participated in a malaria vaccine research trial last year and made it to the bitter end of the trial before getting malaria the day before we were discharged from the hotel. I was the only one left because everyone else had been sick and treated and discharged days before. Why did my body last so long when ever... | [
"Thanks so much for your question and more importantly for your willingness to participate in the trial -- malaria eradication is depending on wonderful volunteers like yourself. In clinical trials like the one you are describing, \"challenge trials\", individuals are vaccinated and then 'challenged' with infectio... |
[
"Why can't the first law of Thermodynamics be mathematically proven?"
] | [
false
] | How can the first law is constantly observed to be true and we call it a scientific law yet we can't say the equation behind it is true. | [
"I think that this is a great instance of where it becomes important to understand the true distinction between a law and a theory. The First Law of Thermodynamics, the equation(s) describing the conservation of energy, is \"true\" in the sense that it is very dependable. Things that we see in the Universe generall... | [
"So then I guess the question becomes \"why aren't there fundamental physical truths that exist independently of the universe.\""
] | [
"So then I guess the question becomes \"why aren't there fundamental physical truths that exist independently of the universe.\""
] |
[
"Does antimatter still exert gravity on matter?"
] | [
false
] | null | [
"We don't know. The Theory says that antimatter should behave exactly like matter when it comes to Gravity, this has not been experimentally verified. Experiments at the Antiproton Decellerator at CERN are currently underway/under construction to measure the effects. We expect the theory to be correct on this, but ... | [
"How precise is our ability to measure gravitational pull? I imagine you'd have to create a ",
" amount of anti-matter in order to get a measure of its gravity."
] | [
"Out ability to measure gravitational pull is actually very good. Almost any college student that took a physics course has done a lab on how to measure it. Obviously physicists have more precise ways to measure it but the actual process to measure gravity isn't as complicated as you might think. In regards to your... |
[
"Are humans the only animals to suffer from mental illness?"
] | [
false
] | null | [
"No",
"Here's chuckles the mentally ill fox"
] | [
"Oh my god that was adorable and sad :) :("
] | [
"Lab chimps",
" seem to show signs of depression and trauma"
] |
[
"When pumping oil, are we leaving vast underground caverns where the oil used to be?"
] | [
false
] | Will this have any longstanding impacts? | [
"No, the oil is in the pore spaces of rock. For example, a major reservoir rock(rock that contains oil) is sandstone. Sandstone is composed of sand and minerals that act as a cement to hold the rock together. There's small spaces in between the sand grains in the rock that hold the oil. ",
"Let's pretend we're dr... | [
"'huge gaps' is pretty misleading. There aren't large continuous spaces. It's porous rock. See ",
"/u/Nothatkindofdoctor",
" 's post."
] | [
"There is currently a debate in both policy and literature of the potential for using these spaces to store and capture carbon emissions. The premise is to re-fill these empty spaces with gaseous emissions as they are air and water tight, and are usually in geogically stable areas. The only access out of the reserv... |
[
"Would you weigh more on the dark side of the moon because of the vector direction of Earths gravity?"
] | [
false
] | null | [
"I like the idea, but the answer is unexpectedly the opposite. The reason for this is because the moon is orbiting the Earth. If you were sitting at the center of the moon, but the moon were gone, you would be \"weightless\", since you would be in orbit around the Earth. Every point on the moon is moving with the s... | [
"The side of the moon that is facing us, is a bit closer to the Earth, and is therefore moving slight faster (in m/s, not in angular speed)",
"the side facing away from us is moving a bit slower (in m/s, not in angular speed)",
"This is reversed.",
"During the course of approximately one month, the moon compl... | [
"So, that can be interpreted as (a) on the side of the moon that is facing the Earth, you feel a bit less gravity from the moon (you want to fall away from it), and (b) on the side of the moon that is facing away from the Earth, you also feel a bit less gravity from the moon (you also want to fall away from it)!",
... |
[
"How do signals from our equipment on other planets make it through the earths core?"
] | [
false
] | Or do we wait to send signals and pictures back until the receiving side of the earth is facing the direction the signal is coming from? | [
"NASA maintains a group of satellite dishes spread around the Earth called the Deep Space Network. Their big complexes are in California, Spain, and Australia. At least one of these will always be in view of any interplanetary spacecraft."
] | [
"You can see which station is supporting which flight project here: ",
"https://eyes.nasa.gov/dsn/dsn.html"
] | [
"Thank you!"
] |
[
"Are there diseases that we are no longer immunized from? If I were to travel back in time, would I be in danger? How long is it considered \"safe\" in relation to our current biologic status?"
] | [
false
] | It's pretty often talked about native americans being erradicated by diseases brought by european explorers and such, but is this issue entirely region-related? I don't understand very well immunization mechanisms but I'm very curious about how we "store" this kind of information, for how long it lasts and such. | [
"Have you ever been to an underdeveloped country? There is a litany of sicknesses you aren't immune to simply because we clean, regulate, treat, and process ",
". You'd run the risk of tons of parasites, many types of dysentery, anthrax, and a bunch of other diseases caused by lack of sanitation or rampant pollut... | [
"I mentioned this in a similar thread but there was a disease common in England under Henry VII called the sweating sickness which seems to have disappeared in 1551. Because it disappeared so long ago we have no idea what caused the disease although a hantavirus and relapsing fever have been suggested but neither t... | [
"This. You may think you're immune from polio but you're not. Most of the things you were vaccinated as a child have now worn off. You'd need a new polio shot to travel in a region with polio. Scarlet fever, Yellow fever, typhoid, hep A/b, tetanus, etc. You'd need new immunizations for those.",
"On top of it, the... |
[
"How much does the atmosphere compress in the direction the Earth is traveling?"
] | [
false
] | I was sitting outside enjoying a bit of rare sunshine on this winter day when I thought about how the earth is traveling around the sun counter-clockwise, and the earth itself is rotating counter clockwise. So if I sit on my porch on a cold winter day looking up at the noon day sun with my head pointed north and my fee... | [
"Compress against what? The biggest thing of Earth's that is distorted is the magnetic field, and that is done by the sun's spray of radiation. The Earth (and its atmosphere) are already settled into a stable orbit, undergoing a constant acceleration from going around in a circular path. If we were somehow able to ... | [
"The atmosphere moves with the Earth. There is no acceleration, so no continued force is exerted on the air molecules. The atmosphere is as thick on the \"forward\" side as it is on the \"backward\" side. The atmosphere might differ in thickness on the equator and the poles however, since the Earth is not a perfect... | [
"There ",
" acceleration, it is in the direction of the sun (because that is the direction of the gravitational pull). In circular motion the acceleration is always towards the center, as acceleration is defined as a change in velocity and velocity includes a directional component.",
"\nAlso, the force of gravi... |
[
"Could gravitons react to objects in the same manner as photons?"
] | [
false
] | As I understand it, we don't even know if gravitons exist or not. However, if they do, would it be possible to attract them to a certain material (similar to how we're able to charge a mass with electrons), or curve them towards something (like how light bends around gravitational fields)? Or am I even approaching the ... | [
"IF gravitons exist, they are excitations of the gravitational field -- quanta of gravitational radiation. Their effects must match the gravity we all know and love.",
"Their interaction strength must be the same as gravity's interaction strength. So, super weak on everything except planetary scales and larger. A... | [
"would it be possible to attract them to a certain material (similar to how we're able to charge a mass with electrons)",
"No (and sort of yes). The first thing to say is, having a charged object does not \"attract\" photons to it -- it just means that the object both absorbs and emits photons. A photon's path ... | [
"Science fiction for now...\nI'm young and can hope.\nAs an optimist I'm still waiting for science to make hoverboards."
] |
[
"What would the tides be like on the moon, if the Sea of Tranquility was full of liquid water?"
] | [
false
] | Or just had various oceans in general such as Earth does? | [
"Keep in mind that some waves which are normally referred to as 'tidal waves' have nothing to do with tides or with the moon."
] | [
"And it didn't freeze or get blown away by solar wind? There wouldn't be that many tides, because the moon is tidal locked, meaning that one face points toward the earth at all times. However, it does 'wobble' slightly, letting us see about 61% of the moon's surface during its full rotational period. Still disregar... | [
"Oh, I had no idea. Do you mean tidal waves also refer to tsunamis and such?"
] |
[
"Why is it that when I try to hold back tears, I experience the sensation of a lump in my throat and have difficulty swallowing?"
] | [
false
] | Whether I'm at a funeral, sitting through a sad movie, or reading an emotional post on Reddit (e.g., today's letter to a son from a father who passed away from leukemia), I always feel that unwelcome sensation of my throat swelling up right before I'm about to cry. I assume it has something to do with sinus passages, b... | [
"The conflict in trying not to cry is being carried out on a smaller scale in the cricopharyngeal muscles in your throat - these are some of the muscles responsible for swallowing.",
"The technical term is a ",
"globus sensation",
".",
"Essentially, as you're reacting to these sorrowful events and trying no... | [
"I don't generally like these types of questions as they're impossible to test scientifically.",
"However, ",
"Jonah Lehrer makes the case",
" that sadness puts one into a ruminative state to prevent negative consequences from happening over and over. Depression is then a pathological runaway sadness respons... | [
"Okay, now tell me; what's the evolutionary purpose for crying at sad things? Or being sad at all?"
] |
[
"How is \"Quantum Decoherence\" not considered to cause actual wave function collapse, and is only viewed as an explanation for the observation of wave function collapse?"
] | [
false
] | When researchers did the double slit experiment with relatively larger organic molecules "430 atoms and 6 nm across" quantum interference pattern persisted, -as in the case of using photons or electrons-, and only got vanished as the researchers admitted gas into the apparatus which "Decoheres the system".. How is that... | [
"Decoherence occurs because quantum states and their environments become endlessly entangled with all the degrees of freedom that environment offers, such a trillion atom detector. All of this occurs while perfectly obeying the time evolution of the quantum state with no funny business. Specifically, if we have a q... | [
"Decoherence happens when you allow your perfectly thought experiment interact with the environment that you do not know much about - you know its classical state, like temperature and pressure of a gas = classical distribution functions - but not the complete quantum state. It so happens that when you have such a... | [
"There are interpretations - like the Many Worlds Interpretation - where there is no physical wave function collapse, but which allow for exactly the same predictions as the interpretations that feature wave function collapse.",
"https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics"
] |
[
"Is it possible to power through a cold/fever?"
] | [
false
] | Could i go running instead of napping to sort of power through the illness? | [
"Cold possibly, fever no. The severity of the illness will determine what you can and can't do. Having an already elevated body temperature while doing an intense exercise regimen could lead to exhaustion or possibly even brain damage or death."
] | [
"I don't really think you could/would. Unless you have a fever of like 104+ your body would be fine. Exercise increases your temperature but it also MASSIVELY increases your bodies ability to lose heat via vasodilation to muscles and skin. To answer the OP, yes you absolutely can. I have gotten \"colds\" and still ... | [
"Your body is trying to kill the viruses by \"overheating\" itself (-> fever), making it hotter than it already is (39°C) won't benefit you. Fever is one of those illnesses you just gotta get over by lying around in bed and helping your body do the work."
] |
[
"Screens cause near-sightedness to eyes, myth or true?"
] | [
false
] | Are there any safety concerns in regards to monitor screens (or any screens in general) to cause any permanent eye issues such as near-sightedness? Does the distance of the screen and the time spent on the screen as well as how dark the room affect any of this?, I've found mixed results online and I'm completely lost t... | [
"the eyes grow so as to increase the focus of the image on the retina. \"ideally\" you're always presenting distant images to the eyes, so they grow into a shape where distant images are perfectly focused (the \"emmetropic eye\"), and nearer images (which require higher optical power to bring to focus) can be focus... | [
"I don't think that's true, myopia onset I think on average is early teens, though it's hard to draw a sharp line for \"onset\" since it's something that comes on gradually. there may be many people for whom minor myopia doesn't become an ",
" until later, like when you start driving in late teens. and it can con... | [
"Very interesting! Are there easy to digest studies you could share?"
] |
[
"Every day our heart makes enough energy to drive a truck 20 miles?"
] | [
false
] | Today I heard it said that every day a human heart produces enough energy to drive a truck 20 miles. That.... can't be right can it? | [
"That doesn't seem to make any sense on the surface.",
"Firstly, the heart doesn't produce energy, it consumes energy and transports energy-carrying blood.",
"Secondly, The average human burns about 1500 calories, or 6,200kj, for 24 hours at rest.",
"A litre of gasoline has about 35,000 kilo joules(35 mega jo... | [
"You mean an impressively fuel ",
" car?",
"You could always put it in neutral and stick it on a slope. Are there any 20-mile-long slopes that would work?"
] | [
"When something \"consumes energy\" it generally means it takes a higher quality form of energy like sugar or electricity, does something useful, and then the energy ends up as low quality waste heat."
] |
[
"Is food treated with Ammonia safe?"
] | [
false
] | First we heard about "Mechanically Separated Chicken," and now "Pink Slime." Opponents are always quick to point out that these products are treated with Ammonia, but is that something we need to be concerned about? Does Ammonia harm us beyond offending our noses? | [
"Ammonia is harmful (by virtue of being alkaline) in large amounts and harmless in small amounts (it's an endogenous substance, after all). It also happens to have a test and a quite strong smell (noticable in parts-per-million concentrations). ",
"Offhand I'd say that if the pH isn't strongly alkaline and/or it ... | [
"That's what \"",
"endogenous",
"\" means."
] | [
"I'll add that everyone's body has ammonia in it; it's a byproduct of our metabolism. Our body deals with it every day."
] |
[
"What makes an allele dominant or recessive?"
] | [
false
] | Is there a chemical difference between a dominant and recessive allele? Is it an evolutionary difference? Are both alleles expressed yet one dominant phenotype is observed? Why are some "undesirable" traits dominant, and some "desirable" traits recessive? | [
"Although ajcreary is right about a lot of stuff, there is a simple answer to this question: The product of the gene has an effect, and dominant effects simply swamp out the effects of the negative allele.",
"For instance, if you have one allele that does not make mellanin, and one that does make mellanin, the v... | [
"Thanks for simplifying; that's what I was attempting to get at but couldn't organize it so well without overcomplicating things. I'm still an undergrad, but this semester marks the end of my biology requirements, so I guess I got a little overzealous as I am wont to do.",
"Thanks again!"
] | [
"No worries... Explaining science on the net has been a hobby of mine since I was an undergrad, which is almost since the net was public.... Anyhow, it takes a lot of practice to be able to simplify down to something concise, without losing too much of the real answer. For what its worth, I thought your answer ... |
[
"Does every galaxy have a black hole at its centre?"
] | [
false
] | [deleted] | [
" ",
" Black holes drive the evolution of galaxies. ",
"The two are linked.",
" A strong piece of evidence we have for this is the so-called ",
"M-Sigma Relation.",
" ",
"Well there might be some exceptions.",
" read ",
"this book."
] | [
"Unless we've misunderstood physics in a very very important way, they literally could not be anything other than black holes, because you could not have that much matter in a small enough space without it being a black hole.",
"The mass is truly ridiculous, it could not even be a circle of neutron stars orbiting... | [
"you're just arguing for the sake of arguing now",
"Actually, from where I'm looking at the discussion, you're the one arguing for the sake of arguing. You seem to be saying that because we don't have 100.0000000% proof that these supermassive objects are not black holes, we should collectively just shrug our sho... |
[
"When did we start cooking our meals? Why?"
] | [
false
] | Genus homo has been around for something like 1.2 million years in some state, yes? When did we decide that fire could be used in this way? Do you think it was taste that drove this? Could it have been fear of disease? Surely the Homo-Neanderthalensis & Homo-Erectus weren't capable of thinking of disease, but observati... | [
"Definitely not an expert in the field, but it looks like ",
"the answer is not really known",
"."
] | [
"Ah, didn't think to look in the cooking wikipedia article haha, I was scouring the articles about early man. ",
"I suppose the most suited to handle this question would be anthropologists or prehistorians, it may be a bit out of ",
"r/askscience",
"'s purview. ",
"Wonderful response, thank you. "
] | [
"I'm not a prehistorian, but I am an archaeologist who studies cooking sometimes.",
"jjberg2's right, we don't really know the answer for sure. It was a very long time ago, though."
] |
[
"How are deep sea organisms not crushed by the pressure of miles and miles of ocean water?"
] | [
false
] | null | [
"Or conversely, how come land-living animals don't explode due to the low pressure at the surface? Answer: the pressure is also low inside a land-living animal, and it is high inside a deep-sea-dwelling animal. They have each evolved differently to fit their particular habitat."
] | [
"Is that why most of the species brought up from deep seas quickly die ? or is there another reason ?"
] | [
"Air breathing animals (seals, penguins, whales, etc) have adaptations that allow them to dive deep, such as collapsible lungs and enriched hemoglobin. Water breathing animals can more easily handle pressure differentials to begin with, but the particularly deep ocean animals also have adaptations to allow them to ... |
[
"Why is conformal symmetry important in String Theory?"
] | [
false
] | For reference, I'm currently studying Bosonic String Theory (Masters level, so basic QFT/GR etc. but nothing too mathematical/complex), so that's my level. Beginning with the Polyakov action, we have the Weyl symmetry of the action on the worldsheet. We use the Weyl symmetry + diffeo to gauge the dynamical metric to th... | [
"Thanks for the links, especially #2.",
"A conformal transformation is one that preserves angles (but not necessarily distance). ",
"Erm, no? ",
"Is it just that we ought to be able to rescale our parameterisations on the worldsheet and the physics (action) should remain the same?",
"I'm guessing that we al... | [
"Any conformal transformation can be thought of as a circle inversion. ",
"No, circle inversions generate the group of Moebius transformations PSL(2,",
"). This group has complex dimension 3. The group of all 2D conformal transformations has infinite complex dimension; it is generated by operators of the form z... | [
"A conformal transformation is one that preserves angles (but not necessarily distance). I think it should be obvious why you would wish to consider conformally invariant objects. ",
"Conf ⊂ Diff×Weyl known as the local conformal group. This is the key thing to think of.",
"See ",
"this",
" and ",
"this",
... |
[
"What's the best way to cool down a room, point a fan from hot to cold or vice versa?"
] | [
false
] | I usually point it from the inside of a hot room toward a cooler area, either outside at night or toward a room with AC during the day. Figured the increased movement of air molecules in the hot area will somehow allow them to cool the room faster as they are displaced and replaced with cold air, but wondering if some... | [
"If you can set up the fan so that it pushes hot air out, and cool air comes in from another source (like pushing hot air out a south-facing window and with a north-facing window open to replace the air), that is the most efficient way to cool the room.",
"The reason is that the fan increases the temperature of t... | [
"Good call on the flag, thanks."
] | [
"Would it not depend on the temperature difference between the two sources? Cold air is more dense and assuming that the fan operates in a regime of constant volume displacement, pointing from the cold into the hot direction should increase convective heat transfer (higher number of lower temperature air molecules ... |
[
"Is there a pattern in the mersenne primes?"
] | [
false
] | I saw a numberphile video on Mersenne primes, and I found out that sometimes 2 to the N - 1 is sometimes a prime. So I was wondering if there is a relationship between the Exponents, N, in Mersennes. Please explain in simple terms. | [
"N has to be prime. If it were composite, then we could write N=AB for some A and B and 2",
"-1 would be divisible by 2",
"-1 and 2",
"-1.",
"This is because of the formula ",
"I recommend multiplying the right side out yourself to get the left side, it's very satisfying. If we plug in x=2",
", then x",... | [
"One way to visualize this is to consider 2",
" - 1 in binary. It is a series of A ones. eg:",
"binary representation 2",
" - 1 is 111111111 ",
"if A = B * C, then it can be expressed as (2",
" - 1) * ( SUM[n = 0 .. C-1] ( 2",
" ) ). In binary, that looks like:",
"111 * 1001001 = 111111111",
"In ... | [
"We do not even yet know if there are infinitely many Mersenne primes yet. If we could find a pattern that said \"N is the exponent in a Mersenne prime\", or some variant, then we would be able to say that there are infinitely many. There are conjectures though. We ",
" that there are infinitely many Mersenne pri... |
[
"Does the placebo effect work the other way around?"
] | [
false
] | And if so, what is it called? I'll give you a hypothetical example. Let's say that I'm taking a prescription drug. I become depressed shortly after I begin taking said drug. After looking online, I find that depression is one of the side effects. I tell my doctor about this, and he switches my prescription to a differe... | [
"That's called the ",
"Nocebo",
" effect."
] | [
"I'd still consider it to be nocebo, although more than anything it's a logical fallacy on the part of the patient. Post hoc ergo propter hoc. I think the only difference between the two (nocebo vs post-hoc) would be whether you could find a true cause for the presumed side-effect the patient had."
] | [
"I don't know if this describes it. A doctor prescribes a patient a drug. By mere correlation he starts experiencing \"x\". He later finds out, that \"x\" is a known side effect of that medication. He tells the doctor this, and he changes the drug. The patient stops experiencing \"x\". \"x\" was later found ",
" ... |
[
"Why schools are teaching wrong information about how the sun works?"
] | [
false
] | [deleted] | [
"I've described teaching as \"lies to children\" (from Terry Pratchet) on AskScience before and caused some small controversy because people saw it as negative. I actually believe that lies to children are necessary and beneficial.",
"We don't mention quantum tunneling because it is far too advanced for the age w... | [
"This is a very warped way of looking at it. ",
"The Sun is not hot because of quantum tunneling or because of heat and pressure.",
"The Sun is hot because it used to be big and when it shrank it got hotter. The Sun stays hot despite radiating away lots of energy because, once the core reached a certain tempera... | [
"This is a very warped way of looking at it. ",
"The Sun is not hot because of quantum tunneling or because of heat and pressure.",
"The Sun is hot because it used to be big and when it shrank it got hotter. The Sun stays hot despite radiating away lots of energy because, once the core reached a certain tempera... |
[
"Might be more history than science, but how did the ancients know that the liver was capable of regeneration, like in the myth of Prometheus? Seems like that knowledge would require several skills we wouldn't have expected from the time."
] | [
false
] | [deleted] | [
"Why would you think the Prometheus legend is an indication the ancients knew liver regeneration was possible? Myths are full of outright false information, and even the myth itself is complete nonsense. They wanted to conjure up a story of a real bad outcome and they did. They could have said his stomach, or heart... | [
"Yeah, but that's sort of a confirmation bias. They didn't contrive the myth that he was immortal because his liver regenerated, but his liver regenerated because he was immortal. There is no attempt to communicate the message the liver is special, just that being immortal is special. Prometheus is a god, not a mor... | [
"Yeah, but that's sort of a confirmation bias. They didn't contrive the myth that he was immortal because his liver regenerated, but his liver regenerated because he was immortal. There is no attempt to communicate the message the liver is special, just that being immortal is special. Prometheus is a god, not a mor... |
[
"How do languages become highly inflected?"
] | [
false
] | It seems like languages tend to become less inflected over time. Modern European languages are generally less inflected than their older versions, which are less inflected than older languages like Latin/ancient Greek/Sanskrit, which are all less inflected than Proto-Indo-European. So my question is: How did Proto-Indo... | [
"It happens through a process known as ",
"grammaticalization",
" wherein lexical words come to take on more functional roles. ",
"In terms of languages becoming more inflected, you just have to look outside of IE languages. The Uralic languages such as Finnish and Hungarian both have a great many cases, ar... | [
"To expand on Jafiki91's response, even though English has overall become more analytic over time, there are several cases of new inflection. These are a good example of how languages grammaticalize bound morphology in general.",
"For example, in English it is now common for TAM marking (Tense/Aspect/Mood) to be ... | [
"particles following the verb or noun are reanalyzed by speakers as being attached",
"This is exactly what I was wondering about. Those are some interesting examples to show how markers attach. ",
"Thank you and ",
"/u/Jafiki91",
"!"
] |
[
"Why doesn't our immune system attack the beneficial microorganisms in our body?"
] | [
false
] | On NPR this morning, they talked about how the majority of the cells in our body are not our own cells, but are beneficial microorganisms. How does our immune system distinguish between a good bacteria and one that would cause a harmful infection? Especially when you consider that some microorganisms (such as e. coli) ... | [
"There have been two main models of how the immune system works. One is the self-nonself theory, which is what you're talking about, where the immune system detects things which are in the body but not part of the body. The other is the ",
"Danger Model",
", which suggests that the immune system identifies path... | [
"The simple answer I can think of is that the gut or alimentary canal going from mouth down to the anus is not actually \"inside\" our bodies, so the micro flora there has not breached a barrier to be detected and illicit a massive immune response. Gut micro flora is actually more of an opportunistic pathogen, and ... | [
"If that is the case then why are there anal infections or people getting sore throats?"
] |
[
"How does the density of a body in motion (at relativistic speeds) compare to its density at rest?"
] | [
false
] | Title says it all. I'll go through my reasoning real quick to see if ya'll agree. Since the object in motion has kinetic energy associated with it, by virtue it also has a slightly larger mass. In addition to this, length contraction decreases the size of the object in one dimension, therefore, it's volume would decrea... | [
"Density is the (0,0) component of a 2-covariant symmetric tensor known as the stress-energy tensor (or alternatively the energy-momentum tensor, or just stress tensor). If you treat a boost as a local coordinate transformation, you see that the stress tensor T",
"{a' b'} = L",
"{ab} L",
"{a'}",
"\nis the J... | [
"In the reference frame of the object, it's the same.",
"If you could make a measurement of the density of an object moving in an inertial frame relative to you, I guess it would go as 1/(1-v",
" /c",
" )."
] | [
"Awesome, just what I was thinking. Thank you!"
] |
[
"The Nobel Prize in Chemistry this year was awarded for super-resolution fluorescence microscopy. How does it work?"
] | [
false
] | null | [
"Normally, in samples you see a diffuse spread of thousands or millions of fluorescent molecules. You cannot resolve these individually because the light coming from each of these particles is \"fuzzy\" and gets blurred out because of the fundamental nature of photons. This fuzziness arises from a limit called the ... | [
"Here's a great video that explains it pretty well."
] | [
"Here is an overview of how it works along with some background on the development. Interesting year since the Physics Nobel was for inorganic chemistry and the chemistry one was more for physics.",
"http://pipeline.corante.com/archives/2014/10/08/the_2014_chemistry_nobel_beating_the_diffraction_limit.php"
] |
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