title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"As a saying in my country goes, when a flesh wound with scab starts itching, it means it has started healing (or is in final stages of it). How scientifically true is this claim?"
] | [
false
] | null | [
"One of the main proteins associtated with wound healing and the contraction/restructuring of a wound are MMPs or Matrix MetalloProteases. These nifty enzymes actually digest the scab from the bottom up, relayering the collagen underneath. They aren't actually involved in the contraction of the wound (that's the co... | [
"Well... kind of. You could say that after the scab becomes itchy it's almost finished the healing that is visible. So I should imagine, if the saying is an old one then to a laymans eyes then yes! It's pretty much true.",
"I mentioned in a different post though that it's not so much finished as it's just beginni... | [
"Yes it does help, thanks for answering back!",
"And since,",
"It (MMP) could be this increase in histamine that is causing the increase in 'itchiness'.",
"and",
"Contractile proteins from wither side then penetrate the scab and join up, forcing the scab up and out. These then contract to pull the walls tog... |
[
"Would a space craft travel faster through a galaxy if it was moving against the motion of the galaxy vs with it?"
] | [
false
] | Perhaps it would be the same as a person walking with the rotation of the earth and make no difference at all. I am just curious. | [
"Sorta.",
"You have to define a relationship. Is your spacecraft traveling relative to Earth? The Sun? The center of the Milky Way Galaxy?",
"Let's say your spacecraft enters Earth's orbit. ",
"Relative to the Earth you could say your speed is 0. Technically it's whatever speed is required to maintain orbit a... | [
"The relative speeds of most objects within our galaxy are too small for relativistic effects to matter. You can simply apply classic physics."
] | [
"Follow-up question. (From another asker. :) )",
"We measure the distance of stars in light years. But wouldn't light from stars we spin away from take longer to reach us that light from stars we spin towards, even if they're equally far away?",
"\nOr is even the speed of light affected by the momentum of the g... |
[
"Can sheets of black phosphorus be isolated in a similar fashion to graphene?"
] | [
false
] | Would isolated sheets of black phosphorus have similar electrical properties to graphene or would the corrugated 'chair' form of the sheets cause the sheets to become unstable and fold due to van dee waals forces? | [
"That's a great question. Based on what I read it might be possible and the best way would to just try it. Calculating/telling you whether you can get one sheet is impossible. You got some scotch tape and a microscope handy?"
] | [
"I don't have a microscope handy not do I have easy access to black phosphorus, however previous studies have shown that the van der waa"
] | [
"?"
] |
[
"Is there a way to visually interpret smells, similar to spectral lines for elements?"
] | [
false
] | null | [
"You can definitely use GC-MS, or just a GC to measure the smells (volatility) of a substance. The technique you'd use would be SPME (solid phase micro extraction) and the intensity of the peaks and what peaks you get depend on things like temperature of the lab, sample, instrument, how long you expose the fiber (e... | [
"The best you could probably do would be to generate a gas chromatogram or something similar, perhaps the retention time spectra from a GC-MS.",
"Smells are generated from millions of different small molecules and so you would have to show some kind of picture that identifies each molecule and its relative amount... | [
"Unfortunately not. The reason is that with light, you have ",
" property that changes (the frequency), and that is easy to map on one axis, obviously. ",
"Smells don't work that way. The average human has about 400 different smell receptors [",
"1",
"][",
"2",
"], which means you have 400 different mol... |
[
"The universe is expanding, but is it measurable within the scope of a single galaxy?"
] | [
false
] | So from my understanding, the universe is expanding, and the rate of expansion is increasing. Are we able to observe this expansion on the scale of a single galaxy? Like, is the space in between the stars in the milky way observably expanding? Or is it only visible at a much larger scale? Thanks. | [
"Single galaxies do not expand ",
". In general, things that are gravitationally bound do not expand. Only space between them expands."
] | [
"The space is expanding inside the galaxy just like everywhere else.",
"Eh, this actually isn't true -- the average energy density inside of a galaxy is enough that even empty space inside of a galaxy is not expanding (this is even true for the space between galaxies that are inside galaxy groups and clusters).",... | [
"The space is expanding inside the galaxy just like everywhere else.",
"Eh, this actually isn't true -- the average energy density inside of a galaxy is enough that even empty space inside of a galaxy is not expanding (this is even true for the space between galaxies that are inside galaxy groups and clusters).",... |
[
"Why is only 10% of the population left handed?"
] | [
false
] | null | [
"There is no definitive answer, nothing but theories currently. ",
"This",
" is a pretty good study that goes over the current theories.",
"One theory has to do with brain dominance. Because of the many decussating (crossing over) pathways there are in the brain, generally speaking the left side of your brain... | [
"most left handed people are also left side dominant",
"For what? I suspect you mean motor speech. There's also hemispheric dominance for written language. Different functions can lateralize independently and some functions lateralize strongly in certain individuals and hardly at all in others. "
] | [
"That sounds like pure speculation.",
"One thing I've always found interesting is that when lost in the woods, people tend to go the opposite of their dominant hand at any given fork, and veer in that direction when they they think they're going straight.",
"If 1/7 people were constantly getting pulled in unnat... |
[
"What is the purpose of sinus cavities?"
] | [
false
] | Was checking out this and it got me wondering what the purpose of these cavities are, especially the maxillary and frontal sinuses. Thanks for the education ! | [
"The sinuses exist to produce mucus. This protects the lower airways by trapping inhaled pathogens and particles, the actions of cilia within the sinuses helps move mucus to the stomach where pathogens can be destroyed.",
"There is some conjecture that they help to lighten and cool the skull as well, but this is... | [
"I forgot about speech, you're right there.",
"I think it's obvious they lighten the skull, but there was debate about why it occured etc and that's what I haven't kept up with.",
"Thanks for including all that though, it's helpful and relevant!"
] | [
"I forgot about speech, you're right there.",
"I think it's obvious they lighten the skull, but there was debate about why it occured etc and that's what I haven't kept up with.",
"Thanks for including all that though, it's helpful and relevant!"
] |
[
"Can turbulence destroy a passenger aircraft?"
] | [
false
] | [deleted] | [
"It's possible but, excepting wind shear, it's extremely unlikely. Planes are made to withstand the conditions they are used in and are much stronger and more durable than the squishy humans inside. You're more likely to die from being bounced around or having an overhead bin pop open and drop its contents on your ... | [
"Please excuse my substandard accuracy and citation. Will fix this when I get to a computer, typing up on phone. My qualification is licensed commercial pilot. ",
"Your comment on wind shear is incorrect. The only way in with wind shear may damage an air raft structurally (independent of the ground) is if it clim... | [
"Well in this case we're talking about very close to the ground, like during or just after takeoff and approaching touchdown.\n",
"http://www.askcaptainlim.com/windshears-weather-66/289-what-is-wind-shear.html"
] |
[
"Boiling water"
] | [
false
] | We are students of The Orchids Public School. We want to try to boil water in an Eco-friendly method. Is it possible to boil a bucket water (app. 15 liters) with a small convex lens? If not, which is the smallest convex lens that can be used? How long will it take to boil and produce steam? What is the shortest and mo... | [
"It depends on what the container is made of. The water itself can't absorb the light energy because it is transparent.",
"The best way to go about doing this is to make a ",
"parabolic reflector",
" and place a black bucket of water in the focus. "
] | [
"Lets do a quick a probably not very acurate calculation for you:",
"Lets consider the water you are using boils a 100ºC=372ºK.",
"Lets also consider 15 liters = 15Kg of water.",
"Lets also consider c remains constant and that your water is at a starting temperature of 10ºC.",
"Also i will consider you woul... | [
"Don't forget latent heat of vaporization! That's gonna take a lot more heat than just getting the temperature of the water to 100 C."
] |
[
"How did our classification of the colours originate?"
] | [
false
] | A friend told me this morning about how some peoples don't distinguish between blue/green in their languages.( ) although of course they can still perceive the difference between the two because this is a biological function of the construction of the eye. Which got me wondering, how exactly have our western colour gro... | [
"Err... what do you mean by \"our classification of the colours\"? There's been a lot of work after Berlin and Kay that, while it may not ",
" their main hypothesis, dilutes it practically to the point of being unrecognizable. You may want to check out Cohen and Lefevre's ",
", chapter 9, which discusses the ... | [
"Thankyou very much for your reply!\nI didn't mean that there was a universal grouping of colours... merely that peoples everywhere have the biological capacity to discern between wavelengths to the same number of nanometres surely? In that I am capable of discerning between different shades of \"red\". I assume th... | [
"There are three levels of analysis in terms of what color might mean. The first is in the eye itself--the cone cells. Essentially, there are three types of cone cells in the human eye: long (sensitivity peaks around 570 nm; \"red\"), medium (peaks around 540 nm; \"green\"), and short (peaks around 430 nm; \"blue\"... |
[
"I've heard the internet weighs the same as a strawberry. How can data, like text saved on a hard drive, weigh anything at all?"
] | [
false
] | (Apologies if this has already been asked, i tried using reddit search but nothing came up.) Is it to do with how we store data with our current technology? | [
"Basically, ",
"information has energy",
". Note that information in the scientific sense isn't technically the same as information in the normal layman sense, but it's kind of similar (for the purposes of the calculation, we're assuming they're equivalent). So once you figure out approximately ",
"how much d... | [
"That's disappointingly less tangible than I'd hoped",
"Oh well, thank you for the explanation "
] | [
"Well, tangibly, the total energy of the internets information is equal to what you'd have to expend to take the constituent particles that make a strawberry, from infinity, then compress them next to you into a strawberry.",
"It's hard enough to get 2 north pole magnets to stay 1mm from each other, let alone get... |
[
"We restrict the supply of antibiotics to those who really need it to prevent (slow) antibiotic resistant strains from evolving. Is there anything else like this in nature?"
] | [
false
] | null | [
"Do we restrict the supply of antibiotics to those who really need it to slow evolution? It was my understanding that antibiotics were over, not under proscribed."
] | [
"Canadians need a doctor's prescription the buy antibiotics and I'm sure this is similar elsewhere. There is at least some semblance of a plan in place to control the distribution of the drug for fear of an increase in resistant bacteria strains. ",
"Anyway it doesn't answer OPs question which is more interesting... | [
"From what I know of the law, prescription drugs are normally prescription because of health concerns or because they are controlled drugs, not fear of antibiotic resistance. Do you have a cite for the reason for antibiotics (which can have serious side effects) being prescribed is due to antibiotic resistance?"
] |
[
"How much of the electricity that a computer uses is converted into heat? And how efficiently does a computer transfer that heat into the surrounding air?"
] | [
false
] | This is something I have wondered for a while. I have heard some tech reviewers and outlets claim that all the energy consumed by a computer is converted into heat. Is that true? Shouldn't some amount of energy go towards computing the information? A second question is, how efficient is a computer at transferring that ... | [
"I have heard some tech reviewers and outlets claim that all the energy consumed by a computer is converted into heat. Is that true?",
"That's correct. Although a tiny fraction of it is converted into light and sound. In a closed room, those will end up absorbed by surfaces and again turning into heat. So effecti... | [
"No, it would be just as efficient.",
"The heating efficiency of a computer is the same as for electrical ",
" heating, but that efficiency is trounced by electric heat pumps which IIRC can be around 300% efficient for air-source and 500% for ground-source.",
"If you're displacing electrical resistance heatin... | [
"Nitpicking here (and I’m sure you already know this, but just to not confuse new players) it’s not really “efficiency” as you can never have more than 100% efficiency (that would be a perpetual motion machine). ",
"For heat pumps it’s called COP (coefficient of performance), and it can be above 100% because we a... |
[
"What is the process for decontaminating sites where nuclear waste is present?"
] | [
false
] | Just wondering the main stages after a nuclear event both long term and after and if there is regulations for it Also any links to interesting videos on the subject | [
"Measure, measure, measure:. Which isotopes in what chemical form. Whats the environmental matrix (sandy soil, clay, etc.). What horizontal and vertical distribution? What's the water table and surface water conditions, etc.",
"Stabilize:. Stop it from moving due to wind, rain, ground water flow, etc. Maybe a... | [
"There's a lot of technical detail, but in the end it mostly boils down to \"collect all the contaminated soil and water, pack it into drums, and take it ... uh ... somewhere else.\"",
"For water, it's possible to use filtration techniques to reduce the amount of water you need to cart away, but there's really no... | [
"but there's really not much you can do to make nuclear waste safe except put it in a drum and wait.",
"Irradiate it with neutrons to convert it to something else is possible. But putting it into a drum is far easier and works well for most materials. Unlike chemical waste, nuclear waste goes away on its own (it ... |
[
"Has the world always had the same amount of water only in different forms? Will it always be the same or can water be destroyed?"
] | [
false
] | null | [
"Water can be broken down into hydrogen and oxygen, such as by electrolysis. It can also be removed by being incorporated into other compounds, as during photosynthesis. Water can be created by the direct reaction of hydrogen and oxygen and, more importantly, by combustion. Thus, to a minor extent, the amount of wa... | [
"For the most part the amount of water on earth has not changed significantly in a very long time. Water is created when you burn hydrocarbons, for instance, or through animal respiration; but compared to the amount of water on the planet the amount that is created this way is miniscule. Similarly, plants break dow... | [
"It does slowly go away in a number of ways. For example when I was 12 I did a school project in which I destroyed water using electrolysis. It is possible that the gasses would eventually reform into water if they were burned or some other random process. Or some of the the gasses which are very light weight could... |
[
"What is better for the environment, a bidet or toilet paper?"
] | [
false
] | Not necessarily just in terms of carbon footprint, but also water usage. Or other effects I haven't thought of. | [
"I don't claim to have a huge degree of knowledge, but I would say a bidet is better for the environment by several orders of magnitude. Toilet paper, and all paper, requires a large amount of water to prepare, not to mention the lose of trees (also require water), the machines used to cut and transport the trees, ... | [
"I found something for you!",
"http://www.scientificamerican.com/article/earth-talks-bidets/",
"I haven't read the article in depth, but this quote should make a TL; DR:",
"To those who say that bidets waste water, advocates counter that the amount is trivial compared to how much water we use to produce toile... | [
"Great answer. People often overlook the amount of water use in the paper industry. ",
"If anyone wants some numbers, here's a halfway decent source in the form of a ",
"Scientific American",
" article."
] |
[
"Are most or all the Yucutan cenotes related to the Chicxulub impactor?"
] | [
false
] | At least some of the cenotes are related to the impactor as clearly shows. But beyond the obvious arc, are the rest of the cenotes related to that impact as well? | [
"Taken from the Wikipedia page:",
"\"Cenotes are common geological forms in low latitude regions, particularly on islands, coastlines, and platforms with young post-Paleozoic limestones that have little soil development.\"",
"The Mexican peninsular is one such place with this Paleozoic limestone. So whilst the ... | [
"I remember being told by a dive guide that the impact fractured the limestone through the entire region, and those fractures ultimately led to the formation of the cenotes. Not sure if it's true or not, though. If it were it would imply the region is more densely populated because of the impact than it would other... | [
"The keyword is 'karst' as cenotes are related to dissolution of limestone through rainwaters. Over geologic time, these caves form. It is likely that fracture systems form some sort of origin for these cenotes as the fractures represent some form of point of attack for the water. "
] |
[
"During a nuclear disaster, is it possible to increase your survival odds by applying sunscreen?"
] | [
false
] | This is about exposure to radiation of course. (Not an atomic explosion) Since some types of sunscreen are capable of blocking uvrays, made me wonder if it would help against other radiation as well. | [
" Oh no. Oh God no. You're so dead. It's not even really the UV rays that do the damage.",
" The important thing to know up front about 'radiation' is that it's a bit of a catch all term, and many of the uses have almost nothing to do with each other. To 'radiate' just means to give off energy. Sometimes that ene... | [
"Hahahah thank you so much for your very educational and entertaining comment! Answered my question perfectly, and made my day a bit better :)"
] | [
"I think I would just add: sunscreen isn't going to improve your odds, but there are things one can do improve your odds. The catch-all solution for \"best way to improve you odds with least amount of effort or investment\" is to go inside. Sunscreen is just a tiny layer of nothing. But a building — especially if y... |
[
"Would we still have the urge to breathe if air was exchanged through some sort of IV?"
] | [
false
] | If we were able to pump blood through a theoretical gas exchange machine that performed the function of our lungs for us (like a dialysis machine but for lungs), would we still have that conscious/subconscious need to inhale and exhale? Or could we just sit motionless without breathing? | [
"Respiratory drive is regulated via a complex system of feedback loops that tend to revolve around measurements of blood CO2 concentration and to a lesser extent blood O2 concentration (we'll ignore the effects of mechanical receptors triggering cough reflexes etc for now). These sensors exist peripherally in the ... | [
"I take care of many patients on ECMO in the intensive care unit. If the sweep is set so that the pCO2 is low enough, you can indeed suppress the native urge to breathe. I have had several patients who have gone apneic or at least very hypopneic. It's not necessarily harmful, except that the atelectasis that devel... | [
"If we use sedation, we will use dexmedetomidine which does not decrease respiration, so the apnea can be contributed to ECMO. Some patients are wide awake on ECMO and don't get any sedation yet still hypoventilate because of low pCO2. It's quite interesting to see."
] |
[
"Why are the Emergency Broadcast tones the specific frequencies that they are? What about emergency vehicles? Are certain sound frequencies able to be heard further away?"
] | [
false
] | null | [
"Don't forget ease of localization for emergency sirens. It's very important that people know where the emergency sound is coming from, if you want them to get out of the way. There are a few things they do to help that. First, use a variety of frequencies, which allows for the shading effects of the head to come i... | [
"The emergency broadcast tones actually trigger automatic systems in the radio/tv networks to break into broadcasts and repeat the message without human intervention. \n",
"http://en.wikipedia.org/wiki/Emergency_Alert_System#section_1",
"As for sirens, the sounds are designed to be heard, over most ambient soun... | [
"It's electrically driven, but the sound is produced by a spinning turbine in air, as opposed to an electronic speaker."
] |
[
"What is the evolutionary benefit from the stripes on a Zebra?"
] | [
false
] | null | [
"If a herd is being chased by a lion the stripe patterns break up and disrupt the lion's vision making it harder to single out an individual zebra to attack"
] | [
"Causes confusion. When they are all in a group its hard to see any one zebra."
] | [
":-)",
"This fly theory will be hotly debated among scientists, I am sure. It goes against conventional theories."
] |
[
"Why, when i stare at this picture, does it eventually disappear?"
] | [
false
] | Here's the photo in question. Stare at it without blinking and it will eventually disappear. But why!? | [
"It's becouse your brain tries to filter out insignificant informtion , this picture is simply abusing this process",
"At least this is what I think this is what is going on"
] | [
"The light-sensitive cells in our eyes fatigue. Normally we compensate for this problem by ",
"moving our eyes imperceptibly",
". If you print an image on a contact lens and wear it, the image will fade away every time, but microsaccades keep this from happening to images in the world.",
"The story is a tad b... | [
"When challenged by a lack of information, the brain tries not to filter out information but to fill in the gaps in the way that it sees as best (sorry for the personification). For example if you have a piece of paper with half pale yellow and half white, then draw a zig zag black line down the middle, as you move... |
[
"Do 2 photons interact with each other when they \"cross\" paths at the same time?"
] | [
false
] | [deleted] | [
"Yes, but it's very very unlikely. It's called photon-photon scattering.",
"http://www.extreme-light-infrastructure.eu/High-field_5_2.php",
"TLDR: You need lasers with ginormous energy densities to produce a meager few events once in a while."
] | [
"The electromagnetic waves would interfere with each other and there'd be an interference pattern. However, on a quantum level the individual photons wouldn't interact with each other. Photons only interact with other photons by producing particle/antiparticle pairs which then interact with each other, and lasers d... | [
"Oo this is my lecturers slide. Got an exam on this tomorrow, woop"
] |
[
"Could the fact that El Nino is so strong this year contribute to how Hurricane Patricia fired up so quickly?"
] | [
false
] | null | [
"Yes, the El Nino this year has increased sea surface temperatures, which ",
"correlates well to hurricane intensity",
". In addition, while Patricia was the strongest Pacific cyclone on record, the ",
"second strongest Pacific cyclone",
" was hurricane Linda. Linda occurred in 1997, the most recent ",
"v... | [
"Thanks for the response!! I'm from Oklahoma so learning more about weather is always something I strive to do."
] | [
"The California Floods of January 1997.",
"https://en.wikipedia.org/wiki/Floods_in_California#New_Year.27s_Day_1997:_Northern_California_flood"
] |
[
"How are quantum computers actually implemented?"
] | [
false
] | I have basic understanding of quantum information theory, however I have no idea how is actual quantum processor hardware made. Tangential question - what is best place to start looking for such information? For theoretical physics I usually start with Wikipedia and then slowly go through references and related article... | [
"In superconducting quantum computing one typically uses Josephson junctions (superconducting tunnel junctions) to make anharmonic resonators that act as qubits. Junctions are made by litography like classical CPUs. Such qubits are prepared by microwave pulses that correspond to rotations on the Bloch sphere. Entan... | [
"Thank you, that is exactly what I was looking for!"
] | [
"There are several different ways people are trying to create large orders of Entangled qubits. One of the most promising methods (which IBM have focussed on) is the use of superconductors called a Josephson Junctions.\nThe Wikipedia entry is a good starting point, especially if you pull up and read through the sou... |
[
"If correlation does not imply causation, what does imply causation?"
] | [
false
] | Presumably since correlation is ruled out, there are other techniques to prove causation. How is causation determined? | [
"I've never been a fan of that particular quip. It is true, but misleading when misapplied. Better to say correlation does not ",
" causation.",
"Correlation ",
" evidence for causation...but not conclusive evidence. It is a necessary but insufficient condition.",
"So what does conclusively imply causati... | [
"David Hume always argued",
" that causation ",
" determined, only correlation can. At some point, we have to assume that things will happen the same way in the future as they have in the past, but that's only based on experience, and unprovable."
] | [
"A randomized controlled trial"
] |
[
"Is there a quantum theory of protein folding? Is it possible that most proteins do not adopt a conformation until measured or directed by some sort of interaction?"
] | [
false
] | Was reading up on the Levinthal Paradox and thought of this. | [
"No, there is not. The question of proteins folding into a certain gemoetry, and the idea of chemical structure in general - that atoms hold more or less fixed locations relative each other - is itself proof that nuclei of atoms do ",
" behave very quantum mechanically and do ",
" have significant (in chemical ... | [
"Natural conformations are not spontaneous. Chaperone proteins help the folding, and sometimes even without them, proteins will fold into a local energy minimum with insufficient energy to get to the global minimum. So, many enzymes are not in there lowest possible energy conformation."
] | [
"Has this belief changed over the last few years?",
"Yes, and it's in the process of changing. By-and-large most undergrads are probably still being taught this (perhaps with a small reservation like I made) but opinion is changing. To me (but I'm coming from the more physical side of things) I've been mostly sur... |
[
"qPCR Error bars?"
] | [
false
] | Hi all -this may be a little lmgtfy but I can't find anything. I'm trying to analyze some qPCR data and I'm not entirely sure how to calculate the error bars. I have figured out rough confidence intervals, but I'm not sure if that's the right thing to do. Advice, further reading is greatly appreciated! Thanks! I real... | [
"You usually use standard deviation or standard error of the mean. SEM is a bit more common.",
"Get the average & SEM for each group and plot as a point with the SEM as the error bars going off that point."
] | [
"I don't really have a reference for it, that's just how I present the data when I publish. As far as I know there's no standard for this kind of thing, you just put it in there how you like it and if a referee has a problem with it you roll your eyes and change it. ",
"I do it that way because that's how my grad... | [
"I think that's what I did. Do you have a reference?",
"Thanks, you exo(-) polymerase, you!"
] |
[
"Why does the equator always get 12 hours of daylight?"
] | [
false
] | Pick the point where the equator is as close to the sun as possible. As the equator moves up or down (in relation to the sun) as the seasons progress, why doesn't the amount of daylight change? | [
"Well the simple answer is, it doesn't. The length of the day does indeed change, although not very much. A matter of minutes."
] | [
"Moreover, it is a point where the angle to the ecliptic plane will be smaller on average. So, if the earth is tilted at ~25°, then the angle to the ecliptic plane at noon will vary between +-25° throughout the year, whereas, say, at 40°N/S, you'll vary between 15° during summer and 65° during winter. "
] | [
"How is the time change so small though? With the earth's tilt being at 23.5 degrees, shouldn't any one point move drastically in relation to the sun throughout the year?"
] |
[
"Do animals know when a storm or hurricane is coming?"
] | [
false
] | After going on vacation I was driving back to south Florida, about where the category 4 hurricane is supposed to hit and I realized that a whole lot of birds, a lot more than usual, we’re moving north and since It’s becoming colder everywhere I thought it should be the other way around where birds migrate south. Now wi... | [
"Other species can sense changes commonly associated with storms approaching. Such as changes in air pressure, temperature, low/high-frequency sounds from the storms. ",
"Here",
" is an example study looking into if birds use barometric changes to predict storms."
] | [
"This is a gigantic leap to make from limited information.",
"First, we can't generalize from \"hurricanes\" to \"natural disasters\". Hurricanes have exceptionally strong winds and low pressures and take days to approach. It's easy to imagine an animal with the right senses being able to detect that something is... | [
"Thank you, very helpful!"
] |
[
"If nothing can travel faster than light, would the curvature of space time be affected immediately or over time if the sun were to disappear?"
] | [
false
] | null | [
"Please see the FAQ"
] | [
"I read it, did I do something wrong? Should I just Google this? I don’t understand!"
] | [
"https://www.reddit.com/r/askscience/comments/7fvmqp/what_is_the_difference_between_gravity_and/dqflbbf/"
] |
[
"Regarding the planets \"trailing\" our Sun around the galaxy..."
] | [
false
] | I was reading , posted in , about the recent . I agree that the video is filled with inaccuracies, in particular calling the heliocentric model wrong. But I had a question about the planetary "trailing". For this question, assume that the solar system disk is perpendicular to the galaxy's disk. This is for simplicity s... | [
"There is no trailing, because the energy of the Sun is included in its gravity wave.",
"Meaning that, you take into account the momentum of the sun when calculating its center, such that even though the Earth gets the information 8 minutes later, that information includes where the sun is \"going\" to be right w... | [
"There is no trailing. Think about things in the frame of reference of the Solar System: the Sun is at the center and the planets orbit around it in a plane. In the reference frame of the Solar System, therefore, there is no vertical lag-- it would be impossible. Thus it is the same for other observers in other ref... | [
"I'm trying to find the thread, but some of the GR experts here have explained how gravity \"leads\" a moving body such that this all works out in the other reference frames."
] |
[
"How was the speed of light measured? And how is a meter based on the speed of light and not the other way around?"
] | [
false
] | Title says pretty much everything. For the second part of my question, I was confused by the wikipedia page, which said: "Its value is 299,792,458 metres per second, a figure that is exact because the length of the metre is defined from this constant and the international standard for time." So how can you define the ... | [
"Ole Rømer first demonstrated in 1676 that ",
"light travelled at a finite speed",
" (as opposed to instantaneously) by studying the apparent motion of Jupiter's moon Io. His estimate was 220,000 Km/s. There have been more recent experiments to make the measurement more accurate.",
"The meter",
" has had ... | [
"I just wanted to add that the meter was probably re-defined in such a way that the speed of light was exactly 299,792,458 metres per second and not 299,792,458.some_decimals."
] | [
"This gives it a little context.",
"As of 2011 the kilogram was the only SI unit still defined by an artifact.",
"Apparently using water to define it just isn't precise enough especially considering how vastly different mass water can have.",
"And from the Wikipedia article on the gram:",
"Originally define... |
[
"do large Cities affect weather in any significant way?"
] | [
false
] | null | [
"Yes. ",
"Monthly rainfall is greater downwind of cities, partially due to the UHI. Increases in heat within urban centers increases the length of growing seasons and decreases the occurrence of weak tornadoes. The UHI decreases air quality by increasing the production of pollutants such as ozone, and decreases w... | [
"This is true. It should also be tempered by the fact that most of these big summer thunderstorms brew up over the plains in areas with little/no urbanization, or they are the result of major weather systems colliding -- they are not local phenomena.",
"To put it another way -- temps in the city are typically a f... | [
"So a fun story I've always liked is from before Boeing had an HVAC system in their Everett, Wa facility. The people and such created so much moisture and the doors opening and closing caused actual clouds to form at the top of the building. So it would actually rain indoors because of it. So a city, even a small o... |
[
"What are some easy, inexpensive experiments to do at home?"
] | [
false
] | null | [
"A good home for this question would be ",
"/r/AskScienceDiscussion",
"."
] | [
"Thank you, kind stranger. I'll take it there, but I will leave this here in case anyone has a good idea."
] | [
"Hey some of these aren't too bad! Thank you!"
] |
[
"Is there a such number system where irrational numbers are the norm?"
] | [
false
] | I don't precisely mean the norm, but I wasn't sure how else to say it. Could e be a terminating decimal in a different theoretical number system? How about tan(x)? I guess this would require different graphing system as well. | [
"Yes, as tliff said, if you use an irrational number as the base of your number system, then lots of our irrational numbers have finite representations in that base. And all of our rational numbers only have infinite representations.",
"However, there does not exist a number system in which ",
" irrational num... | [
"Sure, you could use base e. The math stays exactly the same."
] | [
"Base phi",
" (the golden ratio) is quite interesting because even though the base is irrational, integers are still easy to write without repeating decimals.",
"Changing the base system only affects how the numbers are written, nothing else changes. "
] |
[
"Why does a warm sensation appear in areas where you've recently been hurt (e.g. pulled muscle or sprained ankle)?"
] | [
false
] | null | [
"Redness and heat are caused by increased blood flow. Swelling is the result of the increased movement of fluid and white blood cells into the injured area. The release of chemicals and the compression of nerves in the area of injury cause pain.",
"https://www.nationwidechildrens.org/specialties/sports-medicine/s... | [
"When you get hurt pathogens starts entering your body through the open area. Your mast cells produce histamine and your blood stream gets faster. As it gets faster many immune cells called “Macrophages” starts entering the hurt tissue to fight with the invaders. As they fight, they produce ATP so they do cellular ... | [
"Pathogens don't need to enter for this to happen. If you get hurt the damaged cells will release DAMPs (damage associated molecular patterns) which will stimulate inflammation to essentially isolate the damaged area and bring in monocytes to activate into macrophages to \"clean up\" by phagocyting the necrotic cel... |
[
"Why do CO2 bubbles in soda stick to the bottom and the sides of the container?"
] | [
false
] | Does this have something to do with the adhesion properties of water, such that the outside of the bubble is trying to stick to the container? | [
"There are two parts to the answer. First, the reason you notice more bubbles around the walls of the container is because the rate of bubble formation (or more technically nucleation) is faster in those regions than in the body of the liquid. Such an effect happens not only at the glass-liquid interface, but in th... | [
"CO2 is not stored as CO2 gas in soda, its actually carbonate H2CO3 that is kept this form due to pressure. When pressure drops, the solution becomes supersaturated, which means that the CO2 wants to escape as a gas, but it has reached a stable equlibrium. It needs some motivation. This is provided by small imperfe... | [
"Actually, only a small fraction of dissolved CO2 exists as carbonic acid. Like, less than 1%. CO2 escapes because the soda was bottled under high pressure of carbon dioxide, and atmospheric partial pressures are very low. The nucleation sites on the glass provide a place for CO2 bubbles to form, but they can an... |
[
"Two questions. When an animal (eg. a bird) \"sings\" can it be quantified into musical notes and if so does it fit into a conventional musical key like human songs? Do animals recognize/ appreciate human music? - i.e. can they differentiate when notes are 'out of key'/ 'off key' etc.?"
] | [
false
] | I have two guinea pigs and I play the guitar (acoustic) and sing a lot. Sometimes I'm loud but I see that they tend to fall asleep when I play. So it got me thinking, is it possible that music is soothing to them? When I thought about it some more, I came up with the above questions that I posted. | [
"First off you must understand the concepts of relative and absolute tonalities. Most musicians have relative pitch, meaning they may know that Help by the Beatles is in the key of A and be able to sing the song properly, but without being given a correct starting pitch, they might sing it in the key of G. All th... | [
"IIRC \"talking\" parrots have been the only animals, so far, to demonstrate a sense of rhythm. Not even our closest primate relatives can keep rhythm. The thinking is that the parrots can because it is how the imitate sounds and language. ",
"This leads me to wondering if the Mocking Bird also has a sense of rh... | [
"Hey! Just FYI, but several more animals have displayed rhythmic abilities, including a super cute sea lion!",
"Link: ",
"http://www.ibtimes.com/ronan-sea-lion-keeps-beat-proves-rhythmic-ability-not-just-humans-video-1555835"
] |
[
"If you were propelled into space in a space suit (like the movie Gravity), What would you eventually die from?"
] | [
false
] | null | [
"Lets start with a couple of assumptions. First we're talking about space beyond the earth's orbit. Second, you don't bump into anything, and finally you aren't hurling at speed into a hot or radioactive object like a star. ",
"In that case you will need to contend with a number of factors: lack of food, lack of ... | [
"Well she would most definitely still be in Earth orbit considering the huge difference between orbital velocity and escape velocity. So I'd say that running out of oxygen would be the killer here. Radiation in the time it takes to run out of air probably would be less of a factor.",
"Just checked NASA site, appa... | [
"Would cold really be a factor?",
"On the sunny side of earth, you are going to be at a livable temperature, and on the dark side, you are only going to be losing heat through thermal radiation which is extremely slow.",
"In a LEO, you orbit every 90 min, so 45 light / 45 dark."
] |
[
"How much volume per unit time is the Universe increasing by?"
] | [
false
] | null | [
"According to a ",
"recent article in Science Daily",
", the universe is expanding at 74.3 ± 2.1 (km/s)/Mpc. Now, this is a linear measurement of the expansion of space because it is useful for accounting for the doppler shift of distant objects. You are asking for the volumetric expansion rate. Cubing 74 km yi... | [
"Can you guys dumb that down for me...like a lot."
] | [
"Can you guys dumb that down for me...like a lot."
] |
[
"The origin location of the Big Bang?"
] | [
false
] | null | [
"There was no original point. ",
"The Big Bang didn't happen one place, it happened everywhere. Space itself is expanding from the original point of the Big Bang, so everywhere is its point of origin. "
] | [
"Space itself is expanding, it's not expanding into anything. ",
"If you have 10000km between two objection, eventually you'll have 10001km between them. They haven't moved, nothing has been displaced, more space has been added between them. ",
"The km measurement is way to small, I don't even know how long it ... | [
"Thanks for this! I will give it a few reads later on today when I have time to sit down and properly read it."
] |
[
"Are the size of cells proportionate to the size of the animal?"
] | [
false
] | ie: Do whales have larger brain cells than humans? etc | [
"Cells are limited in size by their volume to surface area ratio because they have to be able to sustain themselves by diffusing oxygen and food into the cell and to their respective organelles, while also releasing waste and synthesized material out. Of course, if you're talking about nerve cells, then that might ... | [
"For the most part, the answer is no. Cell size an animal size are not usually correlated. A larger animal simply has more cells. There are some exceptions to this rule. Fat cells are one such example. Fat cells tend to be larger in larger animals. The reason for this has to do with the ratio of metabolic rate to b... | [
"Only for their size relative to ",
"normal human adipocytes",
", not in relation to other species."
] |
[
"Is there any research or statistics on the long term effects of data skew due to always rounding up decimals ending in 5?"
] | [
false
] | It occurred to me it's pretty minor, but there could be a consistent trend of minutely high readings throughout the entirety of scientific research. Has there been any consideration of this or is it considered too insignificant to concern over? | [
"Significant figures is just a less accurate but more convenient way of showing uncertainty. "
] | [
"Not sure if this is the answer you're looking for, but in most analog to digital converters we run into this issue a lot. Because we can only record integer values with a certain number of bits, the decimals are rounded off to the next integer. But if you consistently round .5 up or down, you can end up with artef... | [
"Generally if you're producing a measurement of some quantity, then you would quote that quantity with an associated error (or uncertainty); say, for example, I measured the average height of 100 men to be 180 +/- 3 cm. The error (uncertainty) on my measurement of the average is 3 cm. In assessing your error, you... |
[
"Will we run out of ingredients for nuclear energy?"
] | [
false
] | If the US built new nuclear plants and use energy solely from those plants, would we eventually run out of the elements to produce nuclear energy? Is there a way to produce more while still producing a surplus of energy? | [
"Eventually yes, but it would take a while. At current usage rates we have identified about 200 years worth of Uranium reserves but there are many ways to extend this. For example we currently waste much of the energy available by not properly recycling spent fuel using breeder design reactors, this would lengthen ... | [
"Fission fuel could provide all our power at current demand for a few centuries up to millenia depending on which fuels we use, which reserves we are able to extract them from, and how efficiently we burn it.",
"Fusion fuels, on the other hand... The first reactors will probably be D-T, deuterium-tritium, and tri... | [
"Eventually possible. However one has to consider that the amount of reserves of a given material is always changing depending on e.g. price. For example near where I live, there was a tunnel drilled through a mountain for the highway. The workers had to wear Geiger-Müller counters when drilling because there were ... |
[
"Artificial Scents"
] | [
false
] | Do artificial scents fool animals? or just humans? If we covered a tissue in artificial bacon smell, will a dog think its bacon? or are those scents only fool the less developed human nose? | [
"Artificial scents are used for animals as well as humans. Cadaver, bomb, and drug dogs are actually trained using vials of \"decomp human 5d\" and \"cocaine scent\", etc. Certain types of insects are attracted to human perfumes and hair products as well. ",
"In terms of \"bacon smell\", dog and cat treats hav... | [
"is it a 100% correlation? If it works on humans it works on animals? I assume there are some differences. Thank you for the answer"
] | [
"There isn't even a way to test this, but we can safely say no, just on the basis that even within humans, response to artificial scents is different. For example, some people think artificial lilac scent smells ",
" like lilac, but I think it smells like offensive laboratory chemicals. True lilac, OTOH, is one... |
[
"Why are a bodybuilder's muscles \"useless\" compared to a powerlifter's?"
] | [
false
] | Why does max load - low repetition cause Myofibrillar hypertrophy? Why does it give different results than high rep - low weight? How are these mechanisms activated? What's actually going on in there? P.S: If I wanted to study this kind of things, what career should I study? Kinesiology? | [
"It really comes down to \"training specificity\": essentially your body responds to specifically what you train for. So training with max load / low repetition improves your performance at exactly that.",
"Myofibrillar hypertrophy comes into play because myofibrals are the structures that actually contract in a ... | [
"I want to clarify the \"useless\" part a bit: Bodybuilders are very strong. However, as mentioned above, the efficiency-to-muscle-volume ratio is quite low compared to other strength athletes such as weightlifters and powerlifters. ",
"In addition to the physiological reasons mentioned above, bodybuilders are ex... | [
"Great responses here, but I wanted to add a note about diet, since that hasn't been mentioned yet and is a huge distinguishing factor between the different types of training.",
"It's basically impossibe to not gain fat while putting on muscle mass (there is some truth to Fat Mac's boasting on always sunny) and t... |
[
"Why does Volatile memory lose all data after shutdown?"
] | [
false
] | Why does RAM lose all of its data after power off? How have we not developed a type of RAM that keeps its data? | [
"We have a non-volatile analogue to RAM: flash memory, like what's in an SSD or SD card. Structurally, the data storage circuitry is laid out roughly the same way as RAM.",
"The reason RAM is volatile is that it stores bits using a transistor/capacitor pair. A transistor does nothing when it's unpowered: it's ess... | [
"Never thought about it that way. Damn now I have to go on a totally different Google tangent as to how flash memory came to be"
] | [
"I don't see how that contradicts anything I said. I emphasized that ",
", RAM volatility is a non-issue. The fact that backup measures exist doesn't contradict that in any way: it just means that there are failsafes which make RAM volatility even less of an issue."
] |
[
"Are vitamin/mineral supplements ever effective?"
] | [
false
] | [deleted] | [
"There is some conflicting research out there on supplements, but to simplify it down - only under specific circumstances.",
"Generally, supplementation can be used effectively to counteract nutrient deficiencies, with success depending on, along with other factors, the cause. Deficiency caused by insufficient di... | [
"Only if you are getting so little of a nutrient that it is harmful.",
"",
"People sort of get things backwards with regards to vitamins/minerals. If you have too little vitamin C, you get scurvy. Having extra doesn't do anything for your immune system.",
"",
"Too little vitamin A leads to blindness, bu... | [
"What makes Omega-3 (for example, Flax Oil) supplements potentially “more usable” by the body than vitamin supplements? "
] |
[
"Is there any theoretical reason why a substance cannot have superconductivity only above a certain temperature, rather than below?"
] | [
false
] | Specifically, is it possible that some hypothetical, undiscovered substance can be superconductive but only above some temperature, rather than only below one, like all the ones I know of do so far? | [
"All superconductors must have some critical temperature above which they no longer superconduct. No matter what force causes the electrons to form Cooper pairs, it always has a finite strength, and thus can be overcome by thermal energy.",
"It is however possible for a material to superconduct only in a certain ... | [
"We have never seen a superconductor with a minimal temperature, all our models how superconductivity works only come with a maximal temperature, and it would be really odd to find something where superconductivity needs a minimal temperature. But who knows."
] | [
"Yes, there are indeed some superconductors (called ferromagnetic superconductors, e.g. CsEuFe2As2) that are superconducting in a domain of temperature under a magnetic field."
] |
[
"What caused the dramatic slow-down of the expanding universe after the big bang (illustration inside)?"
] | [
false
] | In particular, I'm referring to . Looks like things were expanding very rapidly and then everything just immediately slowed waaay down... and now dark energy is impelling an increasing rate of expansion...? Thanks in advance. | [
"Well, like I said, there's a lot of different reasons for inflation. It's not my field, but I talked to a researcher during a poster presentation at a conference, and the impression I get is that there's some sort of field or particle which abruptly falls into a lower energy state, releasing loads of energy and pu... | [
"Your question is phrased as though you're imagining the expansion of space to be like an object with mass and momentum, which has a resulting velocity and then needs some force to be applied to reduce that velocity. When it comes to expanding space, that model doesn't apply.",
"In most theories of inflation, th... | [
"So, \"expansion\" and \"inflation\" actually refers to spacetime itself increasing in size (which I guess could otherwise be said \"size increasing in size\"), and ",
" a bunch of stuff racing outward in a roughly spherical shape *into the empty spacetime medium\"..?",
"If it's the former, I can kind of unders... |
[
"Is there credible research linking antiperspirant usage to breast cancer?"
] | [
false
] | null | [
"As far as I remember, suspicions are/were centered on aluminium (which as far as I understand is the \"useful\" chemical in antiperspirant products).",
"The SCCS (Scientific Committee on Consumer Safety) of the EFSA (European Food and Safety Agency) is in charge of answering this kind of question for the Europ... | [
"Thank you for explaining the process and for linking me to the publication! :)"
] | [
"Great response, thanks!"
] |
[
"Can you harvest the spin energy of an object? Can objects be spun up in 0 gravity to serve as batteries?"
] | [
false
] | An object that is in motion stays in motion right, so if you were to spin a huge object really fast, and then use a machine to harvest that rotational momentum when energy is needed, could you not spin up an object in space and leave it spinning for as long as you want until you're ready to use its energy? Could spinni... | [
"What you're proposing is called a ",
"flywheel",
" and currently exists."
] | [
"Without big external masses as anchor (like Earth) spinning up/down a single flywheel will make your station spin, too. You can spin up/down two counter-rotating flywheels to avoid that.",
"Flywheels have a poor energy storage to mass ratio, they are not a practical energy storage methods in spaceflight where ev... | [
"Yes, and indeed spacecraft routinely adjust their orientation by spinning internal flywheels up or down. This is useful as no propellant is expended, only electricity which is typically the less limited resource. In the case of space telescopes like Hubble or Kepler it also avoids the problem of accidentally conta... |
[
"What does the math look like when calculating how much force it takes to crush a full soup can with a force coaxial with the can?"
] | [
false
] | null | [
"If the pressure isn't extraordinarily high, you can probably idealize the liquid as being incompressible. I'd expect the liquid to stabilize the can with respect to buckling; the ultimate failure mode may be ",
"hoop failure",
" as the uniaxial compressive load is translated to a hydrostatic load on the can, w... | [
"Am engineer. ",
"/u/chemomechanics",
" is most likely correct, though it will also depend on how thin the walls are. ",
"If you assume the can is perfectly symmetrical and the liquid is perfectly incompressible, you can probably assume the failure mode will ultimately be hoop failure since an incompressible ... | [
"since an incompressible fluid assumes the internal volume of the can won't change, which rules out buckling",
"I don't see why this is true. I can think of a buckling mode where the top half of the can curves inward while the bottom half curves outward, for example. The circumferential circle at the halfway poin... |
[
"What is the energy density at the core of the sun?"
] | [
false
] | I've heard various times that the power density of the sun's core is (perhaps) surprisingly low, along the lines of 300 W/m and that the mass density is pretty high, but I've never heard about the energy density. If say a liter of the sun's core were teleported to Earth and let loose, how much damage would it do as it ... | [
"The thermal energy density is given by nkT. The temperature is ~1.5 x 10",
" K, and the mass density is ~150 g / cm",
" . Since the mass of a proton is ~1.6 x 10",
" g, the number density is ~10",
" / cm",
" . So the thermal energy density is ~2 x 10",
" J / m",
" ",
"As an aside, the power den... | [
"So what is the highest quantifiable amount of thermal energy that can be contained within our universe?"
] | [
"Thanks for the response, but could you clarify about other forms of energy in the sample besides just the thermal? Since stars are largely structurally supported by electron degeneracy pressure, isn't there also a large elastic component of stored energy independent of the temperature? Is there anything else as we... |
[
"Where do courtship rituals among birds come from and more specifically how are they passed along from generation to generation?"
] | [
false
] | For example, I recently read that before copulation a male Kingfisher presents a fish head-first to the female, so that she can swallow it without choking on the fins and scales. Also, courtship feeding among Hawfinches is at times totally ritualised, so that although their bills meet, no food passes between them. Oth... | [
"Well, it basicly comes down to ",
"sexual selection",
". Since this a rather complex topic, I will just give you a quick overview:",
"Female Choice",
": In many species, the female is selecting who to mate with or who's sperm will survive. This has devellopped because it is more costly for the female to pr... | [
"It certain cases yes this is true. When a species of baby birds were cross fostered (babies were separated from the biological parents in two different areas and placed in the location they were not born in with foster parents) It was found the the birds still exhibited behavior of their biological parents even t... | [
"It certain cases yes this is true. When a species of baby birds were cross fostered (babies were separated from the biological parents in two different areas and placed in the location they were not born in with foster parents) It was found the the birds still exhibited behavior of their biological parents even t... |
[
"Under what circumstances could a sea or ocean become carbonated, like a tonic water?"
] | [
false
] | null | [
"A carbonated liquid is a liquid that has carbon dioxide (CO2) dissolved in it. The dissolved carbon dioxide takes the form of carbonic acid. At the surface between water and air, there's a continuous process of carbon dioxide from the air dissolving into the water and carbonic acid in the water breaking up and esc... | [
"So would that make bubbly seas fully possible on other planets?"
] | [
"Depends. Would you consider the soda inside an unopened bottle bubbly? I wouldn’t - it just looks like a normal liquid. The bubbles only appear after the bottle is opened. This would correspond to a sudden, huge drop in atmospheric pressure on the planet. I’m not sure how that would happen. Maybe after a large met... |
[
"Does a flashlight produce thrust?"
] | [
false
] | If light has momentum, does it push against what it is emanating from? | [
"Yes. Since momentum is always conserved, the momentum contained in light has to result in an equal recoil in the flashlight. However, the momentum carried by the light is exceedingly small, especially compared to its energy.",
"Therefore, you can't feel it, and light makes an incredibly poor propellant."
] | [
"Just to add some numbers:",
"The relationship between energy and momentum for light is p = E/c where p is momentum, E is energy and c is the speed of light ( ~ 3.0 x 10",
" m/s).",
"Take a big D-Cell 3-LED ",
"Mag-Lite",
" for example, it puts out 3 Watts of power in the form of light, and roughly 1 kg. ... | [
"Thanks! If you shined light against a perfect reflector in space, would it be pushed backwards? What about a black body?"
] |
[
"Would a lung transplant cure asthma?"
] | [
false
] | If a person with asthma got new lungs, would their asthma be cured? If not, would there be a benefit to having the new lungs? | [
"First, I would like to clarify a misconception I see all through this thread: asthma is not allergy. ",
"They are two different, though related, things. Asthma is a hyperresponsiveness of the airway to stimuli, and on eof the potential stimuli is allergy. Most asthmatics have high IgE, but not everyone with high... | [
"CLARIFYING EDIT: Yes, a lung transplant and the management thereof is not worth it for asthmatics. The following answer should be taken as a strictly academic discussion of the question posed in the OP.",
"There isn't a clear answer, as there isn't much published on the topic, and the root cause of the hypersens... | [
"The average life expectancy following a lung transplant is about 5 years. Only about a quarter of patients make it to 10 years. There is also a great risk for transplant rejection, so lung transplant patients have to take immunosuppressants to \"tame\" the body's immune response. These immunosuppressants weaken yo... |
[
"My laptop generates so much heat that it becomes painful to the touch. Could this massive amount of thermal energy be harnessed and converted to other useful energy, such as to charge the laptop battery itself?"
] | [
false
] | In particular my MacBook Pro becomes extremely hot. I have a gazillion things running on it all the time and never shut it down. It emits so much heat spread across the bottom panel that it feels like it is burning your skin when you touch it and you have to pull away really quickly. | [
"In short no, because the waste heat from a laptop is pretty low quality. ",
"If you were really so inclined, yes, you could use the laptop as the power source for a heat engine (a Stirling engine would probably be a good starting point). For the sake of argument, let's say that the laptop is reaching an averag... | [
"sort of off topic, but most people don't seem to know this; regularly taking the back cover off of your laptop and removing the massive amount of dust that builds up stops most overheating problems. The first time I did it with my laptop, i pulled out a solid clump of dust the size of an iphone from a single fan. ... | [
"Nope, he meant low quality.",
"High quality heat provides a large temperature difference such that the Carnot efficiency is higher."
] |
[
"How does moving faster than light violate causality?"
] | [
false
] | [deleted] | [
"Special relativity tells us, given how events appear to one observer, how they will appear to another observer, when those observers are moving relative to each other.",
"So you can ask in special relativity what would happen if an object traveled faster than the speed of light (but still going forward in time).... | [
"If A causes B, and the effect of A travels to B faster than the speed of light, there will be frames of reference in which the effect B happens before the cause A.",
"So if I can mail a letter to you so it travels faster than the speed of light, for example, then there are frames of reference in which you can re... | [
"So what seemingly hasn't been explained in this thread is that the laws of physics (that we know) are Lorentz invariant. This means that all inertial reference frames have to be physically equivalent. This is a well verified result.",
"In particular this means that only events separated by null or timelike dista... |
[
"Why is it that as a human I cannot just look at another animal and determine its gender?"
] | [
false
] | I have met dogs that do not like to be around males. I have read an article about a female chimp who was masturbating to a copy of Play Girl magazine. Why can't I look at an animal and just know if it is a male or female without any other knowledge that may determine its sex (genitalia, color patterns, size, etc.)? | [
"Sexual dimorphism is sort of a spectrum, some animals exhibit it greatly, while others don't. It's most prominent when the animal is sexually mature, including with humans. Also, your experience with humans far outpaces your experience with other animals.",
"For some animals, it may be difficult to determine gen... | [
"It's most prominent when the animal is sexually mature, including with humans.",
"Yeah, people don't realize how much boys and girls look alike before they hit puberty. Get rid of gender-specific clothing and \"other\" (like earrings for example), and don't cut their hair, and unless they're nude it's very hard... | [
"They have a much better sense of smell than you. "
] |
[
"How do the lipid nanoparticles in mRNA vaccines trigger membrane fusion?"
] | [
false
] | As far as I know, enveloped viruses have proteins that cause the viral envelope to fuse with cell membranes. It doesn't look like the vaccine lipid nanoparticles (LNPs) have any such proteins, so why are they able to fuse with cell membranes without them when viruses don't seem to be able to do that? Also, is there any... | [
"LNPs do not trigger membrane fusion. The mechanism of entry is macropinocytosis or endocytosis. This creates an endosome and the charge ratio of the mRNA to the cationic lipids facilitates endosome escape of the mRNA.",
"https://www.nature.com/articles/nbt.2634",
"https://www.nature.com/articles/s41467-019-122... | [
"The necessary mechanisms are part of the target cells themselves - the vector only needs to have the correct lipid composition in order to fuse with the appropriate target cells (what is actually being regulated is the net charge of the LNP).",
"Organ selectivity can also be achieved by adjusting the proportions... | [
"Membranes consist of lipids. Lpids are hydrofobic and fuse together. Lipid nanoparticles physicaly fuse in the cell walls.\nAlso lipid nanoparticles are not proteins and our immune system is searching almost only for proteins. mRNA istelf is altered to avoid attacks from immune system."
] |
[
"What is unresponsive wakefulness? What does it mean to be awake but unaware/unresponsive?"
] | [
false
] | I have been trying to read about the difference between a coma and a vegetative state/unresponsive wakefulness. The main difference I keep reading about is that patients in the latter have wakefulness but not awareness. I am having some trouble understanding this. What does it mean to be awake if you are not aware? Wha... | [
"Basically the brain can be objective observed to be conscious or unconscious. Being unresponsive but awake will essentially be that all the signals say the person is awake, but there will be no other activity occurring.",
"In terms of a coma you could look at this as the brain being switched off, everything may ... | [
"I see, thanks! That's very interesting; if it's not too much trouble, I'd love to hear more about these objective signs of consciousness!",
"Also, would it be accurate to say that a vegetative state is \"worse\" than a coma in that case? Because something must have gone very wrong for someone to be awake but una... | [
"In short, Wakefulness is the ability to experience Awareness. Awareness requires Wakefulness, but the opposite is not true.",
"In basic terms Wakefulness is mediated low in the brain via the brainstem. Awareness is a higher cognitive function that requires the higher brain to be functioning.",
"A wakeful perso... |
[
"Feeling the difference in size of Earth and Jupiter..."
] | [
false
] | null | [
"The surface gravity of Jupiter is about 2.5 times that of Earth. What that means is that every thing would be about 2.5 times heavier. ",
"Would there be a different \"feeling\"? Yes. One's body would feel heavy. For example, it would be difficult to old one's arm out straight. This is because you arm has a mass... | [
"I understand that it has no surface and I knew the gravity was more substantial, I guess it was a poorly worded question. ",
"Disregarding the gravity and lack of surface, what about looking off into the distance? Would it be obvious that the surface area is 80 times that of earth?"
] | [
"Not really. On the ocean, for example, the earth looks completely flat to the naked eye. On Jupiter, looking out over the horizon would look flat as well. "
] |
[
"Why, when two people whistle very loudly, do i here a strange 'wobbling' noise in my head? Details inside."
] | [
false
] | My brother and i can both whistle very very loudly. A few moments ago when we were standing close together, he started whistling as loud as he could and i joined in, in a kind of 'who can whistle the loudest competition'. We both simultaneously heard a 'wobbling' noise in our head, which sounded similar to the scratchi... | [
"You are hearing a ",
"\"beat\" frequency",
".",
"What is happening in your case is that there are two (approximately clean) sine waves whose main frequencies are close. An observer (including machine) hearing both sums them and gets a signal with an envelope (modulation of the apparent strength) that varies ... | [
"This is very likely the thing you're experiencing. Naturally you two are probably trying to match the pitch of your whistle but are missing it just slightly. This slight mismatch in pitch causes the beat frequency."
] | [
"Thanks for answering! Strange phenomenon to experience!"
] |
[
"At what time in the evolution of man did we lose our penis bone?"
] | [
false
] | According to Wikipedia most primates including the other great apes have a , but humans don't. Are there any knowledge indicating at what stage in the evolution of man, that this bone disappeared (if indeed it is completely absent)? | [
"There are many views on the various little changes that were made when the division began and ancestors to homo sapiens began to form - questions like that are somewhere within the fossil record! The bone in question is called the baculum and is found in all primates sans a few other species. ",
"Some papers sug... | [
"Thank you for the Great explanation and the informative links.",
"It is interesting that other primates much further away from humans have also lost this bone in what I assume is parallel evolution.",
"Since humans have essentially had to develop a substitute mechanism for keeping an erection, it would be inte... | [
"why do you think it's a good thing? Just curious"
] |
[
"What did the mile-high ice sheet covering North America look like?"
] | [
false
] | I’ve read lots of references to the Laurentide ice sheet being a mile thick layer of ice covering Canada and part of the US but I’m struggling to visualize what this would look like. Did it eventually slope down to ground/sea level at its edges? Or could you walk on dry ground next to it with open air on one side and a... | [
"Did it eventually slope down to ground/sea level at its edges? Or could you walk on dry ground next to it with open air on one side and a mile high wall of ice on the other? ",
"More the former than the latter. There was a recent question and answer that went into much more detail on this particular aspect, so I... | [
"Thank you for citing references during your response. Thank you also for taking the time to answer these questions so well."
] | [
"Thank you. I feel like I just had a free class on glaciology. Awesome response."
] |
[
"If I run say 10km right after I wake up without eating anything first, what will my body be burning for fuel: fat or muscle? Or both?"
] | [
false
] | [deleted] | [
"Not if you are running 10 km. Glycogen stores do not last all that long under active excercise. This is especially the case because the OP has already been in a fasting state for 8-9 hours while sleeping. That entire time his body has been burning glycogen to keep his blood sugar constant.",
"Since you are in a ... | [
"You wouldn't run on glycogen stores that long. Within minutes of starting a 10k you would begin burning fat. Aerobic respiration kicks in and you produce a fuckload more glucose 6-posphate through gluconeogenesis than would be produced through glycogenolysis. This produces more than enough energy and sugar ro tegu... | [
"The body really doesn't want to burn muscle, and usually muscle is the last of your body's energy stores that is broken down for fuel. Muscle is made up of a great number of proteins, which can definitely be used for energy in your body by breaking them down, but as you can imagine, muscle is needed to do a lot of... |
[
"Can you explain the concept of tidal locked objects?"
] | [
false
] | I'm sure the concept is so utterly basic for astrophysics that it is glossed over but I can't seem to wrap my mind around it. The earth and the moon are locked which is why the same side of the moon is always facing earth, but why? If the moon is rotating, a lunar day, how is it possible that at some point we cannot ob... | [
"A tidally locked object is when its rotation rate, or how long its \"day\" is, is the same length as its orbital period, or how long its \"year\" is. The moon for example, is tidally locked with earth. It takes 28 days for the moon to complete 1 orbit around earth, and 28 days for it to complete one rotation. Beca... | [
"The moon is also slowly doing this to the earth! ",
"For some slightly off-topic but interesting consequences see ",
"Leap second",
". "
] | [
"Is it possible to calculate what part of earth the moon will \"stop\" over?"
] |
[
"Minimum size for a star?"
] | [
false
] | What is the minimum size for a main sequence star that under goes fusion? | [
"About 80 times the mass of Jupiter. Below that (above about 12 times the mass of Jupiter) they can still fuse deuterium but are generally considered brown dwarves and not stars."
] | [
"The Jeans mass gives a minimum formation mass for a star from a gas cloud under a particular set of conditions. Depending on those conditions, there's no limit to how big or how small the Jeans mass can be. It isn't related to fusion."
] | [
"It's been a while since my days of astronomy, but is that figure related to the Jean's mass?"
] |
[
"Can somebody here explain tides?"
] | [
false
] | null | [
"Probably, but everyone seems to frown upon jokes here, even when they are on topic. Or when they are old and no longer funny and we can see them coming a mile away."
] | [
"A tidal force is a ",
" force -- it's what happens when the gravitational attraction to a distant body varies along an object.",
"Thought experiment:",
"Take three pool balls, and put them in a line, in space. Put a large mass nearby, so that the line of balls is 'pointing' at the mass. OK? ",
"Now, think... | [
"The thing that always confused me in earlier years was why high-tide occurred on two sides of the Earth, rather than just the side facing the moon (let's ignore the Sun). I'll present ",
"this diagram",
" first (the one to the right with the red arrows), then explain what it means.",
"The gravitational force... |
[
"Do scientists have an idea of what caused the Big Bang to happen?"
] | [
false
] | [deleted] | [
"Not really. Most evidence points towards some sort of Big Bang happening, but not really anything about what caused it. Technically, we don't even know what happened at the Big Bang - we have a good idea of what happened after ~ 10",
" seconds after the big bang, but not before that.",
"That being said, some... | [
"Depending on exactly how you choose to define \"Big Bang,\" that may actually be a meaningless question.",
"If you define \"Big Bang\" as \"that era of time that lasted from the instant of the first event to the time of recombination,\" which is not an uncommon operating definition of the term, then it had no ca... | [
"Caused? They barely even know what it ",
"."
] |
[
"Application of Snell's Law"
] | [
false
] | Hey guys, I've been working on this homework problem for a while now, and I've run into quite a bump. I need to find the angle of refraction of light travelling through a medium with normal incidence. It seems to me that Snell's Law fails with normal incidence, and I'm yet to be able to find anything useful in my book ... | [
"You can apply Snell's Law to this situation. It doesn't break down, it just gives a trivial result."
] | [
"This is what I think, but I haven't taken optics/physics for many years, so...:",
"If it's normal incidence, than the light won't refract at an angle- both sides of the equation would be 0, and the light would go straight through. So the angle of refraction is 0."
] | [
"I figured it out; if I solve it symbolically first, I can eliminate any sin(0) terms and get the answer required. Thank you all for input. "
] |
[
"When you \"feel\" the sun beating down on you, is that some part of your body reacting to radiation rather than the normal sense of warmth carried via conduction or convection?"
] | [
false
] | null | [
"There are many ways to interpret your question, and it’s an interesting one, so I’ll try to explore a few aspects. ",
"Ultimately it comes down to the power of your mind to synthesize multiple streams of information and create a conscious experience. ",
"When you feel the sun, that’s radiative heat warming the... | [
"What you feel, temperature-wise, is always conductive ",
"Humans do not feel absolute temperature. We feel “hot and cold” in relation to how quickly materials transfer thermal energy away from us. Something that feels warmer than another thing simply directs thermal energy away from our body ",
" less quickly ... | [
"I learned a lot from your explanation - thank you so much!"
] |
[
"How much of an effect do people listening to a radio station have on the reach of the station?"
] | [
false
] | [deleted] | [
"Please refrain from layman speculation..."
] | [
"This isn't layman speculation. It is an apt analogy of the propagation and attenuation of radio waves with respect to EMR. The only way someone listening to a station affects you is if it is perfectly inline between you and the source and because radiowaves have such a low frequency they are easily able to form ... | [
"About the same as someone looking at the Sun has on the brightness of the Sun to you, but actually much less even if they are between the two of you as radio waves have a much lower frequency."
] |
[
"If object X is on fire, what determines the height of the flame?"
] | [
false
] | [deleted] | [
"A flame isn't really a distinct \"thing\". Superheated gases escape the combustion reaction due to buoyancy and other forces affecting the movement of gases, and shoot upwards. While the gas is hot enough, it glows. The glowing part of the gas is the \"flame\" and the non-glowing part is smoke.",
"It's a little ... | [
"An obvious misspelling."
] | [
"Like any fire there are three necessary components: ignition, fuel, and oxygen. Assuming the ignition is sometheing like a match or spark, the height or intensity of the flame will largely depend on the amount of oxygen and the type/quantity of fuel available."
] |
[
"How did mammals evolve a vertically undulated spine?"
] | [
false
] | Hi all My rudimentary understanding of evolution is: Fish evolved into amphibians, which evolved into reptiles, which evolved into land mammals, which evolved into dolphins and whales. The first three groups have spines that undulate horizontally (fish swim side-to-side, amphibians and reptiles walk from side-to-side).... | [
"Evolution of spinal motion roughly went like this:",
"elasmobranchii"
] | [
"There are many things that had to happen for that transition to occur. You don't just flip your spinal motion without having to remodel the limbs that are attached to it.",
"For example, limbs had to shift from sprawling locomotion (as in an alligator) to erect locomotion (as in a cheetah). This included change... | [
"There's a bit of a misconception there. Mammals do not come from reptiles, nor do they come from amphibians. All of these groups are descended independently from the ancestral tetrapod (though reptiles and mammals are closer to each other than to amphibians).",
"That being said, it seems intuitive to relate the ... |
[
"If two particles are entangled and one is shot into a black hole while the other is on Earth, what will happen?"
] | [
false
] | null | [
"Great question!",
"Nothing will happen to your particle on its own, meaning that any measurement you can make to the particle will not display anything unusual. (If it did, you would be communicating from inside a black hole, which is essentially FTL).",
"However, it'd be interesting if you kept your particle,... | [
"well for a wormhole (which is probably not possible, but let's just play along) it's not true that all the energy behind the horizon is related the outside metric. That's because behind there's a whole other Universe with an asymptotically flat infinity. So at the very least, you should apply the full version of t... | [
"Thanks for the thorough answer, and in particular for the article link. The list of assumptions in section 1.1 is just what I was looking for. The top of page 3 answers my second thought experiment (the one about inverting which region is considered the inside of the surface)."
] |
[
"How did later Apollo astronauts deal with the Van Allen belt?"
] | [
false
] | How did they shield themselves from the radiation while going and coming back from the moon? | [
"The Apollo capsules did have ",
"radiation shielding",
".",
"Even if the craft did not have radiation shielding, the astronauts would have survived. The radiation exposure an un-shielded person would receive passing through the Van Allen belts is 27x lower than a lethal dose. ",
"Source"
] | [
"According to ",
"this",
" article they do. Having cosmic rays impact your eyes in a visible way does not necessarily indicate a lethal level of radiation. ",
"In my own experiments with cosmic ray detectors, I was able to measure at least 25,000 cosmic ray strikes per second in an area the size of your head.... | [
"Common consensus is that the astronauts are seeing ",
"Cherenkov radiation",
". High energy particles (cosmic rays) produce light in the astronauts eyes."
] |
[
"Would food ever spoil in outer space?"
] | [
false
] | Space is very cold and there's also no oxygen. Would it be the ultimate food preservation? | [
"The answer depends on what you mean by \"spoil\". There's not oxygen, so things won't oxidize. There's no atmospheric pressure at all, so the boiling point of water is going to be in the ballpark of -100 C; assuming the food's warmer than that the water's going to boil off pretty quick, \"freeze drying\" the food.... | [
"NASA has done experiments that suggest most food continually degrades in space due to bombardment by radiation and canned goods are pretty much inedible after 4 years, unless something extraordinary has been done to preserve them."
] | [
"Kind of. Exposed to the hard vacuum of space you better hope your lungs weren’t filled with air because that’s going to expand and rupture your lungs (and maybe even your chest, if you held your breath instead of tried to scream). You’d loose most of the gasses dissolved in your blood through your lungs in few sec... |
[
"How can matter remain stable when photons travel at light speed?"
] | [
false
] | Why aren't the atoms torn apart? On a related note why don't photons have infinite energy that also smashes matter and/or accelerates it massively? | [
"Why would atoms be torn apart? Atoms are made of protons (not photons), neutrons, and electrons, all of which travel much more slowly than the speed of light (and can be seen as being at rest).",
"Photons have finite energy. It's not related to their speed, of course, but rather to their ",
" - higher frequenc... | [
"On a related note why don't photons have infinite energy that also smashes matter and/or accelerates it massively?",
"E = mc",
"/√(1-v",
"/c",
"). If you set v to c, then E = mc",
"/0, so if the rest mass is anything but zero, the energy would be infinite. So why don't photons have infinite energy? Becau... | [
"The relativistic kinetic energy expression is not applicable to photons, so this argument doesn't make sense. It's actually E=hf, where h is Planck's constant and f is the frequency of the photon."
] |
[
"What is known about the general impact of climate (specifically average temperatures) on human health? Is it physically healthier to live in a hot place?"
] | [
false
] | Think about two comparable people but one lives in Russia (doing outside work year-round) and one lives in Vietnam with no air conditioning. Does long-term exposure to heat/cold noticeably change how our bodies work? Is there any research with conclusions like "people in hot countries metabolize fat quicker" or "people... | [
"Unsure about longterm, but we know there are fewer health problems ",
"in warmer climates.",
" This is because many winter illnesses are a product of the cold wet weather. Winter is also harsher on children and the elderly, they die much more during cold months than any other season. "
] | [
"As you note, there are so many confounding factors.",
"Before modern heating, living in a cold environment meant much of your life involved breathing in air contaminated with smoke or exhaust gas from stoves and fireplaces etc. greatly increasing the risk of lung disease.",
"OTOH, as anthropogenic global warmi... | [
"On the other hand diseases with very high mortality rate are more common in warm climates. Such as malaria and Ebola."
] |
[
"Why aren't gyms used as powerplants ?"
] | [
false
] | Why don't gym owners harness the work done by gym goers into producing electricity? I'm guessing it'd already be implemented if humans produced sufficient energy. | [
"The energy collected is minimal; the energy collection systems are expensive."
] | [
"No. Gears don't magically produce more energy, they just allow for greater torque."
] | [
"the energy collection systems are expensive.",
"They aren't just expensive in terms of money. It takes a lot of energy to turn copper and iron ore into a generator. How long do you think you would have to spend on an excercise bike to generate enough power to smelt ore? Even with recycled materials, the energ... |
[
"How did humans get to Australia?"
] | [
false
] | [deleted] | [
"There was never a land bridge completely between Australia and Southeast Asia, they would have had to boat across the wallace line and the weber line. The distance wouldn't have been particularly far though. New Guinea was connected by land to Australia though, so the population would have dispersed across both.... | [
"Same way. As I understand it, humans probably crossed via land bridges between South-East Asia (Indonsia/Papau New Guinea) and Northern Australia when the sea level was much lower, due to there being a colder climate and more ice at the poles.",
"If I recall correctly, genetic evidence shows a wave of migration ... | [
"You might be right but it made crossings a lot easier. Especially if you could actually see the land you were aiming for."
] |
[
"Why don't we use superconductors in power lines?"
] | [
false
] | [deleted] | [
"The main problem is that there is no known superconductor that remains superconducting at room temperature. They only work far below room temperature as well, something like -100 degrees Celsius. This of course would be hugely expensive to have widespread in the power grid, so it just isn't cost effective.",
"In... | [
"The other problem is that these high temp superconductors that ",
"/u/LuklearFusion",
" is talking about are not ductile. They are brittle ceramics that can't be made into wires."
] | [
"The other problem is that these high temp superconductors that ",
"/u/LuklearFusion",
" is talking about are not ductile. They are brittle ceramics that can't be made into wires."
] |
[
"When another spacecraft docks with the ISS, does it change the station's orientation or movement with any noticeable effect?"
] | [
false
] | I know next to nothing about physics, and realize that the station is bigger than, like the SpaceX dragon--but I was curious whether the force imparted by a docking vessel was enough to affect the station in a way that was measurable. | [
"No. The ISS is passive during Rendez-Vous and docking manoeuvres. (At most it would assume a different control mode in which it keeps a more constant attitude so that the docking operation is easier). It's the docking spacecraft that approaches gently to match the orbit and velocity of the station, and the actual ... | [
"Short answer: no, definitely NOT relevant.",
"Non-short answer: when something docks the ISS, it's that object that tries to dock the ISS, not the ISS that tries to dock the object. This is, of course, made so that there's less waste of energy to slow down the ISS and put it up to speed when necessary, and also ... | [
"I'll add this to Leodip's comment: The ISS (or any other long-lifetime satellite) gets small disturbances all the time. The Earth, Sun and Moon exert tiny radiation pressures on it. The orbit is not ",
" outside the atmosphere; the ISS rams a molecule once in a while and gets a tiny momentum change. The Earth's ... |
[
"What principles of physics are at work in shaking a ketchup bottle?"
] | [
false
] | I've noticed when I flip a ketchup bottle upside down and shake it with decisive force in one motion when the bottle is closed, all the ketchup rushes towards the cap. When I open the bottle, it comes out with a little bit more force than normal. Is this due to maybe a sort of semi-pressurized vacuum or something? Woul... | [
"Ketchup is a shear thinning fluid, which is a type of non-Newtonian fluid that decreases in viscosity when increased shear stress is applied. This is the opposite of another commonly known non-Newtonian fluid, cornstarch in water.",
"Ketchup is also thixotropic, which means it takes some time to respond to chang... | [
"Ketchup is also thixotropic, which means it takes some time to respond to changes in shear stress. This would mean after you stop shaking it, it takes a small amount of time before it returns to its completely viscous state.",
"How does this work in detail?"
] | [
"thixotropic",
"The viscous behavior of the fluid will depend on its history, depending on the previous states of your flow, your fluid can become less viscous under the action of some stress, and it returns to a more viscous state after a certain time. Basically the fluid is destructurated under the applied shea... |
[
"Several questions about photons as the carrier particles for the electromagnetic spectrum"
] | [
false
] | I know that photons are the carrier particles of the electromagnetic spectrum, but some of the details of that concept I find hard to grasp. 1) Are the photons that carry information from particle to particle any different from those that carry light? And if so, then how? 2) How does a passing particle, say an electron... | [
"The thing about virtual particles, that mediate forces, is that they don't actually exist. That's why they're called virtual. What's happening is that there is an electromagnetic field that is perturbed by the presence of a charged object, and that perturbation can be described mathematically like a particle. But ... | [
"oh. does visible light also qualify as virtual? "
] | [
"No."
] |
[
"Why does a hydrogen bomb need deuterium (aka heavy hydrogen) yet the sun does just fine with regular hydrogen?"
] | [
false
] | If the neutron in the deuterium atom is needed to sustain the chain reaction in a hydrogen bomb explosion, why isn't it needed in the sun? | [
"Fusion in the Sun is a multi-stage process. The initial step involves the fusion of 2 protons into a fusion product called helium-2 or a diproton. However, the diproton is very unstable and often decays back into 2 separate protons. In a small fraction of the cases, the diproton can undergo a process called beta-p... | [
"a ",
"picture",
" to complement your fine words"
] | [
"Lithium is commonly used instead of tritium. Neutrons can split it, producing helium and tritium (plus a neutron for Li-7) - more fuel for further reactions which release more neutrons to split more lithium and so on. Unlike tritium, lithium is not radioactive, doesn't \"decay away\" and relatively easy to handle.... |
[
"What is the meaning of this 31 word short story by Arthur C Clarke?"
] | [
false
] | null | [
"My interpretation is that god first deletes all lines of the code he used to create the universe (Aleph in this case referring to the infinite number of lines used), and then erases it; the difference between delete and erase being that deleted things can be restored, whereas erased things have to be recreated."
] | [
"No, I can't really see that as the meaning of it.",
"But you've just prompted me to re-read it, and now I see the final line as the key point of the story: \"It never ",
" existed.\"",
"The implication of that for me is that once the Universe ceases to exist, that all traces of it ever having done so disappe... | [
"I just found another reddit thread via google and someone says the meaning is that the universe is in the process of being deleted. That doesn't jump out as being the meaning but can you see that as, being compatible with your interpretation or a valid alternative?"
] |
[
"What is \"e\" and why is it used so much/why is it so important?"
] | [
false
] | We use "e" and ln so much in math, but why? Why do we need "e" to determine rates of change and derivatives? What is "e," for that matter, how did someone discover it and how did they know it was important? | [
"/u/TheMightyChodeMonger",
" has provided a great ",
"explanation",
" of the interpretation of ",
" in terms of limits of interest rates or compounded growth.",
"There is, however, another, more calculus-y approach. Many functions can be described compactly by relating them to their derivatives through wh... | [
"e is a representation of continually compounded interest. Interest here doesn't necessarily have to refer to finance but rather how something grows at a certain rate over a certain time interval.",
"Continually compounded interest is where you are calculating the interest constantly as the name implies. Think of... | [
"Well, we don't get a choice what the derivative of 10",
" is. It is what it is no matter what conventions we use. If you didn't know about e, you could numerically approximate the derivative of 10",
" and you'd still find that funny number in front. You might scratch your head and wonder where it came from. Ma... |
[
"Why is it that our immune systems can tolerate someone else's blood of the same blood type as our own but not their organs?"
] | [
false
] | null | [
"This is a little bit out of my field of expertise, but I would figure it's along the lines of blood being 'simpler' than organs. There are only a few major factors (ABO type, rhesus factor, Bombay phenotype, etc.) that affect the compatibility of blood, whereas with an organ there is a whole network of antigens an... | [
"Blood transfusion can be very complicated if the recipient has been alloimmunized and has multiple antibodies. Some recipients need a donor phenotype match that is extremely rare."
] | [
"Yes, but on average blood transfusions are a much simpler affair than organ transplants, no?"
] |
[
"How long after the flyby will it take to get high quality images of Pluto from New Horizons?"
] | [
false
] | The wikipedia article for New Horizons says that "Initial, highly-compressed images will be transmitted within days. The science team will select the best images for public release. Uncompressed images will take about nine months to transmit", but there is no citation for this statement and I can't find a source to ver... | [
"I don't know the specific bandwidth of the New Horizons spacecraft, but it has about 3GiB of onboard data storage. Most interplanetary probes only have a few kbps of down link to Earth and I'm sure the New Horizons team will want every last bit of data collected from the probe. Literally. Add in re- transmission a... | [
"Over 2 years to transmit the full contents in an ideal case at that speed."
] | [
"On a related note, how long will it be before New Horizons can deliver higher quality images of Pluto than Hubble? Will this not happen until a month or two before closest approach? Or maybe a year ahead?",
"Are follow-up questions allowed in top level comments?"
] |
[
"Why are all the planets' orbits on the same plane?"
] | [
false
] | Its almost as if they were just rolling around on the floor, is it possible for a planit to orbit the sun vertically? | [
"The solar system formed from a disc of gas, so when this disc fragmented into planets and asteroids etc, these all had orbits that were still in the disc. Scattering from nearby passes of asteroids can kick stuff up a bit, but generally only for small objects, and not very many of them. There's nothing stopping a ... | [
"Other posters have commented on some general mechanisms that are true but not strict. ",
" ",
"We have an unsolved problem of the ",
"Kepler dichotomy",
" which is essentially that we observe an overabundance of single transiting systems. This suggests that a number of these systems have mutually inclined ... | [
"A rotating sphere of gas will flatten into a disk whether there are collisions or not. The force of gravity pulls particles above the plane of rotation down towards the center of mass, and it pulls particles below the plane of rotation up towards the center of mass."
] |
[
"“Atheist silenced by Adam gene” is this true?"
] | [
false
] | null | [
"Hi Mortalpuncher 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 f... | [
"Biology"
] | [
"This person is a crackpot and preys upon vulnerable people suffering from disease (e.g., cancer) to sell his woo. Avoid."
] |
[
"Does alcohol's negative impact on the liver depend on the BAC, or just the total amount consumed?"
] | [
false
] | If I consume 150 ml of whiskey over the course of a day versus all at once, does it affect my liver's health differently? | [
"Do you mean 150 centilitres? Assuming you don't vomit it back up, 1.5 litres of whiskey is almost certainly a fatal dose if taken all at once.",
"Normally, alcohol is metabolised as follows: alcohol dehydrogenase converts alcohol to acetaldehyde and acetaldhyde dehydrogenase converts acetaldehyde to acetic acid.... | [
"I think the use of 150 cl of ",
" was a bit of an accident (though to be honest, there are people who can consume that much without dying).",
"But I believe what he was getting at, for example; someone was to drink 12 standard drinks. Would it affect your liver if you drank the 12 standard drinks in a short am... | [
"Yes that's what I was getting at. And I meant to put ml, which would make a lot more sense, doh!"
] |
[
"Do DNA mutation rates support the estimated age of life on earth?"
] | [
false
] | We know mutation rates for many different types of organisms, from animals and plants to unicellular organisms (like early life (?)). Can we use these to predict an origin of life? Does that match the age proposed by earth science/astronomy? I was thinking about mutation rates, and realized that I can't really conceptu... | [
"I would need to go do some digging to find references for your first question (and deep time is not really my area), but I can address a few of the others.",
"Does 10",
" base pair mutation rate mean that every base pair in every new individual has that probability of mutation?",
"Yes. That's exactly correct... | [
"Unfortunately I can't really comment on Kauffman's work or ideas, as I'm not really familiar with them. Evolutionary biology is actually a pretty big place, so there are whole subfields that I know fairly little about. To be honest all of the \"complexity\" stuff never really grabbed my attention, so it may be tha... | [
"I can't comment on the biology but I can comment on the Earth Science aspect and the issue is we do not know when life began on Earth. ",
"The earliest evidence we have goes to just over 3.8 billion years ago which comes from carbon inclusions in apatite from Greenland. Older evidence has not been found yet but ... |
[
"Conservation of energy and fusion/fission"
] | [
false
] | Forgive my ignorance on this subject, but I allowed my mind some idle time and this popped in there and I could not find an answer to satisfy the question. I had a thought about fusion/fission in a closed system and that lead me onto wondering if there is an equally impressive (even if only in theory) process is the "o... | [
": Conservation of energy does not imply some reverse process, it just says that the energy you put in is the same as the energy you get out!",
"I think you're confused about there needing to be a reverse process to maintain equilibrium - that's not true. Conservation of energy states simply states that for a clo... | [
"I think the most direct answer to your question is that you can, indeed, hit nuclei lighter than lead hard enough to knock bits out and smash nuclei heaver than leaded together in such a way that they stick (this is how superheavy elements are synthesized).",
"Both of these are entropically disfavored though. Y... | [
"Ok, now YOU get to explain binding energy."
] |
[
"Why don't people with chronic muscle pain naturally develop strong muscles to counteract it?"
] | [
false
] | Say I get a sore back or neck from slouching at a computer all day, or from reading in an awkward position. The pain is because my muscles are too weak hold up my body/head for long periods (I assume). But isn't this pain just like the pain that bodybuilders get from working out? Doesn't this mean I'll get muscle brea... | [
"Postural muscles are very difficult to exercise train. They are predominantly \"slow twitch\" muscle fibers that are constantly being activated to help maintain posture when sitting, standing, walking, etc. ",
"The pain associated with maintaining a poor posture is generally muscle tightening because the postura... | [
"Yoga in general is an excellent way to improve and maintain good posture. If you want to know which specific muscles you're having issues with you'd be better off seeking the advice of a physical trainer or even a massage therapist as every case is different."
] | [
"Yoga in general is an excellent way to improve and maintain good posture. If you want to know which specific muscles you're having issues with you'd be better off seeking the advice of a physical trainer or even a massage therapist as every case is different."
] |
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