title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"What causes computer screens to have colours more/less visible at extreme viewing angles?"
] | [
false
] | [deleted] | [
"The way a LCD monitor works is there is a row of lights at the bottom of the screen and a diffuser screen over top to spread the light out. When you view it from an extreme angle you are viewing through more of the diffuser which distorts the color."
] | [
"Here",
" is a video that explains how an LCD monitor works."
] | [
"You should specify LCD or CRT."
] |
[
"Will we ever be able to view what happens in other planets at a surface level with a powerful enough telescope?Especially planets that are earth-like/inhabitable."
] | [
false
] | null | [
"In theory, yes it's possible. But what do you mean by 'at a surface level'?",
"A group of astronomers recently published a ",
"30 year roadmap for NASA missions",
". In it, they talk about all the amazing science we think we can get in the next 30 years as long as Congress keeps funding us. (If you have time... | [
"Dont you sometimes feel like we were born too late and yet too early to experience some huge breakthrough? ",
" yep there is plenty of extraordinary stuff that happened-is happening during our lives. I just meant things like fusion, interstellar travel or some badass things. But living in a computer age is p... | [
"As someone who is nearly 30, the 2060 number is a tad disappointing. But the thought of having pictures that clear of planets several light years away in my lifetime is amazing. "
] |
[
"How strong would the casing of a nuclear bomb be to hold in a nuclear blast? What would be the effects?"
] | [
false
] | How much stronger than steel does the casing have to be to hold in this energy? Could radiation still leak through? | [
"I can't answer your question directly, but from the ",
"wikipedia article on underground testing",
" a nuclear bomb causes \"temperatures of several million degrees and pressures of several million atmospheres\" (no exact figures given) and buried in rock will irreversibly strain/deform rock in a radius of aro... | [
"The simplest response to your answer is steel itself can hold in a nuclear blast, and prevent radiation leaks. The micro material properties (atomic constituents, molecular arrangement, etc.) of a nuclear blast \"shield\" are equally as important as the macro structural properties of the shield (thickness, shape... | [
"Here's my stab at trying to calculate how strong a container would be needed. First off lets make the assumption that due to the fixed nature of our container that the volume in which the explosion would go off would be of a fixed volume additionally due to the fast rate at which the explosion happens and the rid... |
[
"Do insects need to sleep too?"
] | [
false
] | As in, does the mosquito that pesters me when I sleep need to sleep as well or do small lifespans of some insects means they die before they need to sleep (if they do sleep). | [
"it seems that all animals sleep.",
"here's a good review of the topic of generality of sleep in animals:",
"https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.0060216&type=printable",
"For a quick review, just read under 'Corollary 1' on the first page.",
"Also, worth reading this a... | [
"Dunno. The results are based on observed behaviour, since we can't ask them and they are generally too small to do an MRI. Perhaps, like many birds and fish, they only rest 1/2 a brain at a time?"
] | [
"Sleep seems to be a fundamental feature of any creature that uses neurons to live (i.e. \"animals\").",
"I'm nitpicking but not all animals have neurons or even nerves, sponges for example. "
] |
[
"If you were to hang a wrinkled shirt in a wardrobe, would it ever become unwrinkled over time via gravity?"
] | [
false
] | [deleted] | [
"Fashion Student here.",
"I think it would largely depend on the fabric. For example, if I were to get fabric pleated it would be important for it to be polyester, or have a polyester mix otherwise the pleats would fall out.",
"So, I think that if the shirt is cotton or wool then the creases would eventually di... | [
"Polyester is plastic, versus the other two being organic. It becomes significantly more malleable as temperature increases, such as when pleats are being added. It cools and holds the shape given. Polyester also holds its shape more firmly than the other two when at room temperature, which is why the material is ... | [
"I think another way of asking this question is I hang a spring on a planet will it stretch itself eventually. Of course the answer like many questions is it depends...",
"In the case of a spring we should consider how far from equilibrium it is. If you have stretched it just a little bit then internally its not ... |
[
"If animals of the same species talk the same to each other, why did humans have different languages?"
] | [
false
] | null | [
"I'm not sure what you mean by \"talk to each other\". Non-human animals can communicate, but they do not have language as formally defined."
] | [
"Well, I suppose I didn't express myself correctly. For example, you could take a cat from one part of the world and one from the other, they would be able to communicate."
] | [
"In what way would they be able to communicate? Couldn't humans from different post of the world communicate with signs and gestures?"
] |
[
"Supposing that wealth is redistributed, would inflation still occur even though no wealth is added and why?"
] | [
false
] | null | [
"Redistributing wealth could increase the velocity of money (how quickly money changes hands) because poorer people tend to spend their money rather than save it. More and faster spending leads to higher prices.",
"As an aside, poorer people tend to spend a higher proportion of their money on essential goods like... | [
"(Piggybacking for those who are interested, because this is a poorly-understood topic):",
"Taking it a step further, if we ",
" suddenly facing increased inflation, we could keep it under control via monetary policy (raising the federal funds interest rate) to encourage saving. The increase in spending from th... | [
"There are things besides total amount of money that affect inflation if that's what you're asking. For example, if you were to redistribute all the USD, then people might be scared you'll pull a stunt like that again and lose their trust in it. They'll start keeping their money in other forms, causing rapid inflat... |
[
"Why does the plot of x^x have such a \"weird\" shape around the origin?"
] | [
false
] | At a large enough scale it looks rather uniform, like an exponential function, but it has a rather odd shape around the origin that isn't uniform and doesn't seem to make sense. How come it does that? Why, at around 0.4, does it seem to flip the other direction? I mean, I can see by literally multiplying the numbers th... | [
"The minimum is at 1/e",
". You can show this by taking the derivative of x",
" (it might help to rewrite it as exp(x log x) ) and setting it equal to 0 and solving for x.",
"If we take the convention that 0",
" = 1, and we know that 1",
" = 1, then if the function remains smooth it has to change directio... | [
"Well it's not a convention that 0",
" = 1, but it is true that the limit of x",
" is 1 as x decreases to 0. "
] | [
"x",
"=e",
", so its behavior mimics xlog(x). (Compare them ",
"here",
".) Below x=1, there is a push-pull between x and log(x). x is positive and wants to go to zero, but log(x) is negative and wants to go to -infinity. Three things can happen: 1.) x wins and the function goes to zero, 2.) log(x) wins and ... |
[
"How can spectroscopy show the Sun is made of hydrogen when the Sun is a plasma"
] | [
false
] | How can spectroscopy show the Sun is made of hydrogen when the Sun is a plasma (and is therefore at temperatures high enough to prevent any electrons from falling back into orbit and emitting the characteristic photons)? I understand the Sun's light comes from it's photosphere which has a temperature of about 5777 K bu... | [
"Thanks, this was the key. Hydrogen doesn't exist solely in the plasma state until 60,000K (though that comes from the same internets that said it's all ionized at 5000K). "
] | [
"To some extent that depends on what we call the \"surface\" of the sun - being a ball of gas it doesn't have a surface so much as a point at which that gas becomes mostly transparent. So you have light given off at or below this cutoff point which then passes through the transparent gas beyond and produces an abso... | [
"Hydrogen is barely ionized at all at 5000 K. Only around 10000 K does hydrogen become overwhelmingly ionized. The Sun's surface temperature is about 5777 K, and the outer layers of the atmosphere are even cooler, so there is plenty of hydrogen absorption in the solar spectrum."
] |
[
"In psychology, what's the relation between priming and availability heuristic?"
] | [
false
] | I've been reading Thinking, Fast and slow by Daniel Kahneman. It's an amazing book which does a pretty good job of explaining wide ranging psychological concepts/phenomena in an accessible fashion. But I do sometimes get confused when concepts are laid out separately and no mention of their relation is given. It could ... | [
"I assume that there could be a relationship between priming and the availability heuristic. I could for example imagine that people can be primed by the news to believe that airplane accidents happen more often as car crashes since the news usually reports on airplane accident quite a lot while they do this less o... | [
"Thank you for taking time to respond to this old query. Your first paragraph dispelled my doubts. Thank you. "
] | [
"Thank you for taking time to respond to this old query. Your first paragraph dispelled my doubts. Thank you. "
] |
[
"How much salt would I need to be able to float in my bathtub as if it were the Dead sea, would it work?"
] | [
false
] | Can I use kitchen salt? Why would it work? Why wouldn't it work? If the answer to #2 is no, why does it work in the Dead sea? | [
"The general rule of thumb for salt water aquariums is 1/2 a cup of salt per gallon. The Dead Sea is 8 times saltier then that so 4 cups per gallon. The average bath tub holds 50 gallons so 200 cups of salt are need. 1 cup of salt weighs approx .6 pounds so you need about 120 pounds of salt. Mix well until all salt... | [
"Dead sea salinity is 275 g/kg with nominal density of 1.24 kg/l (wikipedia). Average bathtub is about 150 liters.",
"150 liters -> 186 kg of solution -> 51 kg (115 pounds) of salt.",
"Math checks out, yes it would probably work with kitchen salt.",
"EDIT: See answer below, Dead Sea salinity (33.7%) cannot be... | [
"No, it does not work. See my answer below",
"edit: Copy and paste so you don't have to search for it:",
"The saturation point of NaCl in water is around 5.27M, about 307g/L (I work in a lab) which is 30.7% w/v. The Dead Sea is at 33.7% salinity due to the combination of other salts present such as KCl, MgCl2, ... |
[
"What are the mechanics behind some animals having a good sense of smell?"
] | [
false
] | There seem to be several measures of a "good sense of smell". Some animals seem to be able to pick out one scent among many others. Other animals, like sharks supposedly smelling blood in water miles away, seem to be able to sense minuscule portions. Do both these capabilities boil down to the same basic functions? Wha... | [
"It's generally put down to the size of the olfactory epithelium and the number of active olfactory receptors genes.",
"That is, the amount of tissue within the nose that has cells that express receptors for picking up smells can vary a lot. A human has about 10 cm",
" of olfactory epithelium, a dog can have up... | [
"Thank you"
] | [
"What have you heard about quantum mechanics in relation so smell? I once remember a guy (spoke on TED) who proposed that smell has many quantum properties? "
] |
[
"How did they come up with expiration dates? Did they try every situation possible? \"Whole milk room temperature, whole milk refrigerated\" and monitored the food? Or did they just estimate it based on the food's composition?"
] | [
false
] | And then counted the number of days the food was sitting there? And then how did they know if it went bad? edit: Thanks everyone for the nice answers. | [
"Expiration dates are somewhat arbitrary. The dates on packaging is not regulated or tested. Too many variables affect a food's actual quality to just go by the printed date.",
"A good source on how long ",
"a food lasts",
" and, for extremely durable food, look at the ",
"MRE shelf life"
] | [
"I used to work for a food manufacturer. To measure expiration dates we would take about 10 samples, store it in a fridge or freezer depending on the product, and test it regulary, varying from daily to weekly. We would compare the shelf life test results against the same product specifications used for general qua... | [
"Amont the many variables that affect such regulations, there are also political reasons. In Greece there was recently a debate about the expiration dates of milk. If kept at 4 days, it would be practically impossible for central european dairy powerhouses such as Austria to export milk to Greece. They made it 7 da... |
[
"Can the time periods of seasons change?"
] | [
false
] | I don't know if I asked this right. What I mean is, can the seasons change over lots of time that our summer months (June, July, and August) could be "winter-y"? And our winters could be hot? Not including global warming as a factor. Just our planet's course through space. | [
"That is actually the reason most calendars that depend on the day/night cycle have leap days/weeks/months/years. In short, if we didn't have February 29th every 4 years, yes, we would eventually shift the seasons around the calendar's year.",
"I.e. Earth's orbit around the Sun doesn't take an integer number of d... | [
"Cleanest perspective I've seen in awhile. How easily we forget that calendars are arbitrary and not an innate measurement.",
"Makes me wonder what else we measure out of convenience that distorts reality."
] | [
"For one, June, July, and August are winter months in the Southern Hemisphere already. Because of the way we've defined our season, however, our summer will always be relatively warm compared to winter. That said, the lengths and relative intensities of seasons (at least at a specific location) ",
"can change dra... |
[
"How did ancient man get enough salt in their diet?"
] | [
false
] | I recently changed my diet to be more sodium free, and found that very few foods actually have a natural source of salt in them, which made me wonder how hunter-gatherers who don't live near the sea (or even do) got enough salt. How did they even know that they needed it? | [
"The body only needs sodium ions, not salt in particular. Sodium is found naturally in plenty of foods: eggs, meat, fish, nuts, raw fruits and vegetables. Pretty much every organic food source has some trace of sodium in it, though admittedly not as much as we eat today. ",
"Which is why people have to go on low ... | [
"You also need chloride, which you can get from a lot of other sources too, so this isn't entirely true.",
"Basically, you need them both, but they don't have to be together as 'salt'."
] | [
"Ah yes. The original poster seemed to be asking about sodium in particular, but you're definitely right about the chloride too :)"
] |
[
"Would it be possible to power some machine by 'plugging it in' to the body, resulting in no effort calorie loss?"
] | [
false
] | My knowledge of weight loss is basically if you consume less energy than you spend, you lose weight. So if you could spend energy on powering some machine with the energy in your body without actually physically turning a turbine or something, could this make it easier to get to a caloric deficit? | [
"Some engineers at MIT have been developing a ",
"fuel cell",
" that runs on glucose for powering implanted medical devices. I suppose you could use that technology to simply idle and consume glucose, but if it consumes a significant amount of glucose, it's going to make a significant amount of heat."
] | [
"How about it channels it into a usb port so you can charge your iphone on the go?"
] | [
"So can water, you're going to have to qualify that statement. What mechanism does it kill you with?"
] |
[
"Watching the sun from outerspace."
] | [
false
] | Well, in a lot of games you can watch the Sun in outerspace. But I was wondering, can you watch the Sun in outerspace without getting blind/eye damage? Because if you look at the sun from Earth your eyes will hurt a lot. EDIT: Sorry for not setting the right Category, I'm not sure where this belongs to. | [
"No, looking straight at the sun while in space without shielding would be blinding. In games this is possible because there is generally not a mechanic for retinal damage."
] | [
"It depends on your distance from the Sun. If you're in Earth orbit, or closer to the Sun than Earth, yes, it will cause damage. Farther from the Sun, somewhere around Jupiter, the intensity falls below the threshold for retinal damage."
] | [
"Thanks, thats all I needed to know."
] |
[
"Another Special Relativity Question dealing with time."
] | [
false
] | [deleted] | [
"It was a joke. Settle down."
] | [
"I won't try to convince you it was a very ",
" joke…"
] | [
"There have been too many questions on special relativity and time today. This one maxes out our quota. Please hold off on submitting any more questions on special relativity and time until tomorrow when we reopen for business.",
"The answer to your question is no. There are no fixed points in space, all inertial... |
[
"Over what range of frequencies are superconductors impervious to electromagnetic radiation?"
] | [
false
] | I'm assuming that due to the Meissner effect that low-frequency radio energy couldn't reach the interior of a hollow superconductor. I'm also guessing that atomic dimensions are too big to counteract radiation on the scale of gamma rays. Could a sort of super-Faraday cage be made of a superconducting shell, and if so, ... | [
"Looking at some papers about a high temperature superconductor, ",
"they are pretty bad at reflecting UV and higher radiation",
" while ",
"it approaches 50%",
" for wavelengths in the millimeter (infrared) range."
] | [
"It's a complicated subject. The frequency dependent response of superconductors is an important measurement of their microscopic properties. It varies by the pairing mechanism (which determines the symmetry of the order parameter) and by the specifics of the system you're looking at within a particular class. As f... | [
"the best materials can deal with around 30T at near 0K?",
"Quite a bit higher than that. The materials I worked on in grad school had ",
"Hc2(T=0) over 30T",
", and those are by no means record holders: optimally underdoped ",
"YBCO",
" has Hc2 so high that ",
"you can't measure it directly.",
"What ... |
[
"Is it possible to rip a black hole into two pieces? How might that happen, and what would happen?"
] | [
false
] | null | [
"I must apologise for the terse reply of my fellow panelist but he is correct. ",
"The really important part of the black hole is the singularity at its heart. A singularity is not an object with size in any real sense, so the notion of halving one is tricky.",
"Don't make the mistake of conflating a black hole... | [
"No."
] | [
"Getting tired of talking about black holes? X)"
] |
[
"CO2 levels above 945ppm, a normal rate in indoor environments, have been shown to reduce cognitive function by 15%. What is the most efficient way CO2 can be removed from indoor air in situations where ventilation is not feasible?"
] | [
false
] | Study Referenced: Cognitive function scores were 15% lower for the moderate CO2 day (~ 945 ppm) and 50% lower on the day with CO2 concentrations of ~1,400 ppm than on the two Green+ days (Table 5, dividing the average Green+ estimate by the moderate CO2 and high CO2 estimates, respectively). Are algae scrubbing setups... | [
"The International Space Station uses ",
" zeolite to scrub CO₂ by ",
" adsorption, and the ",
" zeolite can then be regenerated by heat. The equipment is called the Carbon Dioxide Removal Assembly (CDRA).",
"*edit: zeolite not LiOH per ",
"/u/RuNaa",
"'s comment below."
] | [
"Houseplants. ",
"https://www.mnn.com/health/healthy-spaces/photos/15-houseplants-for-improving-indoor-air-quality/a-breath-of-fresh-air"
] | [
"After planting a few succulents in my spiders' enclosures, I didn't some research to see if they could produce enough oxygen to keep a spider alive on their own. During that research, I read that the total decrease in CO2 one can expect from a reasonable number of plants is insignificant. Much less than 1%, if I r... |
[
"Does gravity affect itself?"
] | [
false
] | Does gravity have an affect on itself, weaking its external force on other objects? | [
"Gravity does self couple. The gravitational field created by mass itself has mass and this changes the gravitational field. This is why the field equations are non-linear."
] | [
"Einstein's field equations for General relativity, equate the curvature of spacetime (and any gravitational effects) to the energy/momentum density of spacetime. It's a complicated set of equations, but it is fairly easy to see that no, gravity does not self couple."
] | [
"This is actually a research topic on general relativity (GR) and leads to heated discussions between experts. There is no well defined \"energy\" term for gravity, which means it does not formally appear as a source for itself in the field equations (in technical terms, there is no stress tensor associated with it... |
[
"At what point did Earth become... Earth?"
] | [
false
] | What I mean to say is at what point can scientists say that Earth existed? I often hear the number of ~4.5 billion years as the age of our fair planet, but based on the prevailing theory of accretion and protoplanets, at what point did this planet go from being a protoplanet to being Earth? At what point can we say tha... | [
"It is still \"forming\" as you put it because it has a molten iron core and plate tectonics. If you are talking about habitable to life it would be around 4 billion years ago. \"The name Earth originated from the 8th century Anglo-Saxon word erda, which means ground or soil. In Old English the word became eorthe, ... | [
"The formation of Earth refers to getting all the mass that makes up Earth to Earth. It has nothing to do with volcanoes or plate tectonics. It is only a question of the material getting to Earth."
] | [
"The formation of Earth is a well defined question. Once Earth finished accreting Earth was formed. The fact that heat is left over doesn't affect when Earth formed. It affects Earth today but the formation ended long ago."
] |
[
"How does human muscle fiber compare to that of other animals?"
] | [
false
] | Let's say that we are comparing 180 lb. specimens and that all have the same amount of muscle fiber, say roughly 75 lbs. or so. In terms of strength, endurance, explosiveness, etc. how would the muscle in the human compare to other mammals (jungle cat, bear, gorilla, etc.)? Is it pretty much the same stuff or is there ... | [
"I don't know of any specific studies to point you to, but I do remember that one group of scientists had done this study among primates. Turns out a female orangutan (in heat)is pound for pound the strongest primate. They tested using a one-arm pull test. Humans max out at around 200 lbs.-maybe 400 pounds if you... | [
"Thanks!"
] | [
"I don't know much about the differences in muscle fiber between species, but I'd like to point out that bone/tendon/muscle geometric arrangement accounts for much of the differences in strength between humans and other animals.",
"Compared to most other animals, including our closest primate relatives, human lim... |
[
"Why do some animals move in quick bursts (like chickens/small lizards) while others are more deliberate (like humans/bears)?"
] | [
false
] | null | [
"The short answer is: smaller animals are more agile, and usually move in quicker bursts, than larger animals, because they have less momentum. A lizard's head/legs/whole body weighs much less than a bear's. Because of this, very little momentum is required to start and stop the movement of the small animal's bod... | [
"I think we, if we had our same brains, would still move more like a chicken if we were lighter, but that's an interesting question. You are wondering if larger animals are maybe more 'calculating' in their movements, and therefore would use less small, rapid movements because maybe those movements are wasteful?",... | [
"This makes sense, but I’m wondering if there’s a sort of psychological component. As in, if we were much lighter, would we still move like a chicken with out more complex thinking patterns? "
] |
[
"Is it bad to have my laptop resting on my reproductive area while laying in bed?"
] | [
false
] | i am in currently in this position as i ask. | [
"If you are a male, your most pressing issue would be any heat produced by the laptop. Exposing your scrotum to heat will decrease the viability of your sperm. This affect can last several weeks to several months, depending on how often and the duration that you expose yourself to this additional heat. There are... | [
"Yes. ",
"Its always bad to put a laptop on a fabric surface. Fans blow out hot air and suck in cool air. When your laptop is on your pants its sucks up lint and dirt and this can gunk up your computer, possibly burning out fans and causing damage from overheating (I've seen it happen)."
] | [
"Just took Fertility, Sterility, and Mammalian Development. It will slightly decrease your sperm count briefly, but there haven't been outcome-based studies that have effectively addressed the actual effects. When sperm are maturing, it happens in the sertoli cell. Heat variance can effect the binding between the s... |
[
"If a Normal Person with a Healthy Weight Started Consuming Only Water and Vitamins, How Long Could They Survive?"
] | [
false
] | I saw a video recently that mentioned a ~500 pound man who went over a year without any caloric intake, and consumed only water and vitamins. Under the same conditions, how long could a normal weight human do the same thing? I've always been told that people can go 2 to 3 weeks without food, but usually, that was in th... | [
"2-3 weeks on the short end. Here's a very long medically supervised fast, described in great detail, which ",
"lasted 382 days (Post Graduate Medical Journal - 1973)",
"."
] | [
"I would be worried about the health of the intestinal lining and flora. I scanned the study, and didn't see any information about how they reintroduced the subject back to normal food. I would love if a gastroenterologist (or someone who knows) could chime in!"
] | [
"\"No faecal collections were made, but evacuation was in fact infrequent, there being 37 - 48 days between stools...\""
] |
[
"How do unvaccinated individuals put vaccinated individuals at risk for viruses like Measles?"
] | [
false
] | There's an article on the front page about how "anti-vaxxers" have brought back the measles in places like New York City, where outbreaks are now occuring. I understand how these people can catch the virus and spread it amongst other unvaccinated individuals (including toddlers too young to be vaccinated), but the arti... | [
"No medication, or vaccine, is 100% effective.",
"A lot of what we consider the effectiveness of vaccines, is that if you can get x% of the population vaccinated, the target disease fails to infect enough hosts to continue to survive, and essentially dies off in that population (or herd).",
"So, even if my vacc... | [
"I think this argument has been turned around. No doctor really cares if a healthy vaccinated adult contracts the measles. What they are concerned is whether infants including infants in utero, young children, or immunocompromised individuals get infected as they are vulnerable.",
"The concern about healthy adult... | [
"I presume you are talking about ",
"this",
" article.",
"The point behind vaccines and getting \"everyone\" vaccinated is to cultivate herd immunity. This is where you have perhaps 80% of the population that will not become sick and spread disease. Vaccines are not 100% effective; depending on the ",
"va... |
[
"What do we mean when we refer to the age of the universe?"
] | [
false
] | If gravitational time dilation means that the speed of a clock is affected by the mass in the local area of space, then different physical regions of the universe will have different times elapsed since the big bang. The age of the space inhabited by the solar system will be different to that in the intergalactic vacuu... | [
"The age of the universe is computed in a ",
"comoving reference frame",
", a specific reference frame where the cosmic microwave background is isotropic -- also sometimes called the \"CMB rest frame.\" This frame essentially has the minimum possible proper time elapsed since the CMB. Other reference frames, ... | [
"the time dilation due to Earth's peculiar velocity would be only about 10,000 years ",
"The age of the universe is the CMB frame is the ",
" possible age of the universe. Any observer in motion with respect to the CMB frame will measure that the universe is ",
" younger. In principle, we could imagine some p... | [
"Yeah, you're right, it's my bad. I was too focused on looking at the difference in magnitude of the effects, and not on whether it went one way or the other. I guess I glossed over it since the point I wanted to emphasize was why the difference in magnitude compared to the error bars made compensating for the ef... |
[
"Why is it so hard to make a vaccine for the Herpes Simplex Virus?"
] | [
false
] | [deleted] | [
"you can check out ",
"this article",
" which describes the efforts to making a vaccine against Herpes. If you've got a bit more biology under your belt, ",
"this article",
" is about how the herpes virus works, and includes some of the biology of why its hard to make a good vaccine.",
"A couple main poin... | [
"it's pretty high on my list. does that make me selfish?"
] | [
"thank you!"
] |
[
"Does climate science predict we've warmed the earth in the first place?"
] | [
false
] | We hear a lot about temperature reconstruction in the past up to the present. Ostensibly, the temperature has been increasing, and this is often said to be what climate models predicted. But is it? My only evidence for doubting this is this figure: This shows the expected value of total anthropogenic radiative forci... | [
"Those aren't standard deviations, they are 90% confidence intervals. The graph indicates that the available data suggests the total anthropogenic forcing is somewhere between +0.6 and +2.4 W/m",
" with a 10% chance that they lie outside of those values (either above or below)."
] | [
"I am not an expert in climate science, but I will note that those error bars are not showing standard deviations. They are in fact 90% confidence intervals. See here for the original figure caption:",
"http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-5.html"
] | [
"Ah, that would change things. This is a strange metric though. I'm currently calculating the 90% confidence point to be about 1.16 standard deviations, my work: ",
"http://www.wolframalpha.com/input/?i=solve%28+erf%28x%29%3D0.9+%2Cx%29",
"Then, if we use your numbers of 0.6 and 2.4 we can find how many stand... |
[
"Will de-ionized water still heat up in the microwave?"
] | [
false
] | [deleted] | [
"Yes. The ",
"mechanism for microwaves passing energy to water",
" (",
"dielectric heating",
") does not depend on the ionic strength (salt content) of the water. Salt water or low ",
"TDS",
" water will heat up in a similar fashion."
] | [
"Microwaves heat water molecules directly.",
"http://en.wikipedia.org/wiki/Microwave_oven",
"Water, fat, and other substances in the food absorb energy from the microwaves in a process called dielectric heating. Many molecules (such as those of water) are electric dipoles, meaning that they have a partial posit... | [
"It will heat up. However, be very careful about doing this: there may not be sufficient nucleation sites for the water to ",
", especially with quality smooth glassware and a nonrotating microwave. Much like supercooled liquid water freezing when shaken, superheated water can explosively boil upon the introducti... |
[
"Can the distribution of protons to neutrons within the nucleus affect the shape of the orbitals, and through that the location of the electrons?"
] | [
false
] | If somehow the distribution of the protons & neutrons in the nucleus is such that protons are on the 'right' and the neutrons are on the 'left', wouldn't this create a more positive electrostatic charge towards the right of the atom, so it would be more reasonable to stay electrons are found there, correct? Through thi... | [
"Sort of. The overall structure of electrons around a nucleus is largely determined just by the charge. Quantum mechanics allows us to figure out how the electrons are organized based on the electrostatic attraction.",
"Then there is something called fine structure, where the energy levels of different electron s... | [
"That is really cool, thank you. With that in mind, then, are the effects near negligible? "
] | [
"Well, it depends how precisely you measure it. Hyperfine transitions are very important for astronomy and also materials science and atomic physics. The second is defined based on a hyperfine transition in cesium."
] |
[
"With the big bang theory of inflation, what caused matter to slow down?"
] | [
false
] | So I was reading about how after the big bang . So what caused the expansion to stop after that fraction of a second. That seems like a pretty extreme change in speed especially without friction in space. Was it dark matter? Or if we technically never stopped and the universe is still moving at the same speed, why don'... | [
"I'll let actual experts answer your questions, simply wanted to note that this",
"I would assume the stars that made it further away from the big bang were moving at a higher rate of speed than the ones who didn't quite make it as far from the point of origin.",
"is based on an incorrect premise. There is actu... | [
"You're complaining because we don't yet have a complete theory of what happened 10",
" seconds after the big bang?",
"The theory explains some of the phenomenology, but not all. This is the case with nearly every scientific theory ever invented. Scientific progress involves reducing the unexplained stuff, bu... | [
"So what caused the expansion to stop after that fraction of a second.",
"The expansion didn't stop, only the acceleration. The universe continued to expand.",
" the acceleration started and stopped is not a solved problem. It is postulated that it was caused by a field (similar in many ways to the dark energ... |
[
"Would dust storms on Mars really be as bad as portrayed in The Martian?"
] | [
false
] | I understand the winds get up to ludicrous speeds, but with the air pressure at 0.06 atmospheres would it be as damaging as the book/ movie portrays? | [
"No. The most violent windstorm on Mars would feel only as strong as a stiff breeze. That's why, at the climax, it was reasonable for the orbital vehicle to take off with only canvas in place of its armored nose cone. ",
"The author has said in interviews that he knows this was a scientific inaccuracy. He used th... | [
"How is the dust toxic?"
] | [
"Absolutely not. Even the most 'violent' storms on Mars barely have more push than the force exerted by you exhaling normally. The dust kicked up in these storms however is really bad. It's toxic (so you need to clean your suit before taking it off) and it will get in to ever seam or hole of every machine on mars.... |
[
"If Covid-19 mutates to the point that the vaccine will be ineffective, will it be easier to make a new one or it’ll take the same amount of time?"
] | [
false
] | [deleted] | [
"It took 2 days from obtaining the SARS-CoV-2 genome to formulating the vaccine and less than 4 weeks to manufacture the first batch of vaccines (",
"source",
").",
"If a new variant were to emerge that would require a new vaccine, it would probably be created in a similarly short time. It's the trials that t... | [
"Similar to the influenza vaccine it's possible that small modifications of existing vaccines could be approved faster."
] | [
"Also, even if we decided to approve them rapidly, it would still take quite some time to actually manufacture the updated vaccine in sufficient quantities. The current vaccines are able to be rolled out so quickly after approval because they've been manufacturing them for months prior."
] |
[
"Why is the value of e, e?"
] | [
false
] | I am talking about the natural constant. I am wondering why e shows up everywhere. Why is it that very different things resemble e? For example, continuous interest has e in its equation while the amount of electrons in a capacitor has a natural logarithm (log base e). Why is this so? I assume e is just a number just l... | [
"The constant e (",
"Euler's Number",
") has a unique property -- it perfectly represents the rate at which natural systems grow or decay.",
"I might start out periodically increasing a quantity by some ratio, say, 10%, like this:",
"x' = (x+x/n)",
"If n = 10, then x' = x * 1.1. So I have increased the va... | [
"Small gripe, it's actually Euler's number, not constant. ",
"Euler's constant",
" is an entirely different number."
] | [
"That's what he said, that's the limit that defines e",
" ",
"lim n->infinity (1 + x / n)",
" = e",
"\n, not e. ",
"e = lim n -> infinity (1 + 1/n)"
] |
[
"Nuclear Bombs dropped in the same location"
] | [
false
] | If multiple nuclear bombs (let's say 3) where to be consecutively dropped in the same exact location would the blast radius (or total area destruction)increase. Let's say they were 1 megaton each and dropped, (perhaps, 10 seconds apart) would the blast radius expand? Or would it decrease due to the crater deepening? Al... | [
"I don't know about 10 seconds apart, but the Pacer Project at Los Alamos created designs for a generator that would have been powered by small nuclear weapons detonating repeatedly in an underground chamber. One source claims the final design spec'd 45 minutes between explosions, which sounds a bit fast. AFAIK i... | [
"If it were physically possible to detonate bombs in the same location in such quick succession, I would imagine the blast radius would increase because you're increasing the pressure in the area, forcing more and more air from the central point. I doubt it would be all that noticeable though, other than having mul... | [
"Thanks! That clears some things up."
] |
[
"Why are comet trajectories difficult to predict?"
] | [
false
] | I've heard it said that comets do exactly what they want...meaing that it is notoriously difficult to forward model their trajectories. Why is it so difficult to measure and predict the orbit of newly discovered comets, given our knowledge of mechanics and our astrometric capabilities? | [
"The other issue with comets is they melt. This melting can produce geysers of material which act as a rocket booster changing the comets trajectory."
] | [
"indeed, although the effect is extremely small, the chaotic nature of the orbit makes it very important."
] | [
"I would think that the large bodies that affect them would be limited to the Sun, the 8 planets, and a few other largish asteroids and trans-Neptunian objects. Since we know these orbits extremely well, we should be able to do better for short duration events like astroid approaches. I know that > 3 body orbits ar... |
[
"Why do protons not repulse themselves in atom nuclei?"
] | [
false
] | As particles with positive charge, they should NOT be aggregated. Why then are atoms (such as, lets say, uranium) posible? | [
"Protons ",
" repel each other due to the Coulomb force. However the Coulomb force is not the only force present in nuclei. There is also the residual strong force between nucleons (and the weak force, which has relatively minor effects on the structure of nuclei).",
"The residual strong force is usually attrac... | [
"this webpage has a handy graph explaining just that",
"strong force graph",
" "
] | [
"One way to think about this is in terms of two major forces acting on protons in a nucleus.",
"The first as you note is electromagnetic repulsion (Coulomb force). Like charges repel like, so positive protons should repel positive protons. Protons ought not like to be next to each other.",
"But the second is t... |
[
"What would happen if the moon had a geostationary orbit?"
] | [
false
] | Hello! Please let me know if this has already been answered and I'll delete it, but I had a question (Frankly, an idea for a science fiction novel). What would be the effects on the earth if the moon had a geostationary orbit? I'm assuming that it would be at the equator, and closer to earth than it is now, but what... | [
"This is actually the case for Pluto and Charon: they are tidally locked to each other, so Charon is always in the same place in Pluto's sky and vice versa. The moon is tidally locked to the Earth but the Earth isn't tidally locked to the moon or to the sun. ",
"There could potentially be a solar eclipse every da... | [
"Tides would be much stronger",
"Tides happen because the bulge in the oceans rotates with the moon at a different rate than the Earth spins around its axis.",
"With the moon at fixed point there won't be any tides. The sea level will be constant (ignoring the Sun's effects) albeit with a higher sea level at so... | [
"This is the definition of tides from wiki:",
"Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.",
"There won't be any tides (there is no periodic change), but there will be a bulge (as you state it... |
[
"Etiology. Isn’t “where to begin” the ultimate question?"
] | [
false
] | null | [
"Etiology’s short-comings are “at root”* that we as a species are literally detached from our environment—the natural cycles of our earth and the solar system too have become strangers to us. The origins of change in general then are “ beyond us” & yet the “burden of proof” so near.",
"*pun intended"
] | [
"medicine"
] | [
"medicine"
] |
[
"How do far away space probes like New Horizon account for the motion of the Earth and the probe during communications transmission and reception?"
] | [
false
] | At over 4 billion miles away, the signal would take 6 hours to reach Earth which would have moved about 389 thousand miles. Does the probe account for this motion and realign its transmission antennas? Edit: Apparently, there would not be too much precise calculations due to the frontal lobe of the signal spreading out... | [
"New Horizon and the voyager spacecraft are a few light hours away. The Earth doesn't actually move that much in that time frame. The signals they send out are not collimated that much. Over time they will spread out and cover enough area that antennas on Earth can pick up that signal. \nBoth Voyager probes have le... | [
"fyi: the Voyager space craft are about 20 light hours from Earth. New Horizons is about 5.7 light hours from Earth."
] | [
"The transmission antenna ",
" highly directional, but on the other hand at these distances the beam width may be millions of kilometers and still count as highly directional. But calculating where Earth ",
" be isn't very hard in case it has to be accounted for.",
"One thing that does matter is the Doppler s... |
[
"Concerning \"germs\" (bacteria, viruses, etc), what is the difference between an immunity developed by an individual, and an immunity inherited via genetics?"
] | [
false
] | null | [
"The Europeans had immunity to various diseases because they were exposed to them. It was not 'genetic' in the sense you are using."
] | [
"The natives were exposed to them and they died en masse. Something is different."
] | [
"The natives had never been exposed to those diseases or any similar strains of infectious agents. Europeans grew up around those diseases and mutant strains that are less infectious, and were able to develop immunity. "
] |
[
"What's the benefit of slitted pupils?"
] | [
false
] | null | [
"Full article",
"Basic summary: slitted pupils allow us not to block out certain wavelengths of light when using a multi-focal lens, meaning that we get more color focus.",
"This",
" article explains it in plain english that, essentially, you get better color vision in low light, which explains our kitties wh... | [
"Hi! This is a scientific subreddit for scientific questions and ONLY scientific anwsers which come ONLY from science. You're most likely being downvoted because you are posting a top-level comment, (a reply directly to the OP), that is off-topic or speculation. Top-level comments in AskScience should only be factu... | [
"Hi! This is a scientific subreddit for scientific questions and ONLY scientific anwsers which come ONLY from science. You're most likely being downvoted because you are posting a top-level comment, (a reply directly to the OP), that is off-topic or speculation. Top-level comments in AskScience should only be factu... |
[
"Why does the Earth spin, and why doesn't the moon?"
] | [
false
] | null | [
"The moon is ",
"tidally locked",
" to the earth, which doesn't mean it isn't spinning, what it means is that it takes the moon the same amount of time for one rotation as for one orbit. That is why one side always faces the earth.",
"Most of the time, one the smaller object is tidally locked to the body it i... | [
"It is a rather complicated thing called ",
"Angular Momentum",
".",
"It is difficult to explain in simple scenario, but as a big ball of gas and rock starts to become more dense through gravity, it generally forms a rotating object. This is due to all the matter coming in with specific trajectories, and this... | [
"If it helps, you can also read my ",
"comment",
" in the other thread."
] |
[
"How much radiation would you be exposed to holding weapons-grade plutonium in your hand?"
] | [
false
] | In a movie I saw yesterday there were several scenes of the characters holding spheres of weapons-grade plutonium in their bare hands with seemingly no concern for how radioactive it is. My gut says this is a really, really bad idea, but I'm curious just how bad it would be. How much radiation would you be dosed with ... | [
"It depends on how much of it you’re holding, and whether or not criticality is reached. The “common” isotopes of plutonium are radioactive to alpha decay, but Pu always comes cladded in other metals, which the alpha particles can’t penetrate. Some fraction of the time, it will undergo spontaneous fission instead, ... | [
"For the effects of being exposed to radiation from supercritical plutonium, ",
"see the incidents involving the demon core",
".",
"Note that the plutonium itself in this case is a subcritical mass that went supercritical due to its proximity to neutron reflectors, which probably caused some complacency by th... | [
"Yes, the cladding is due to the chemical properties of plutonium, which are very nasty. It also provides some radiation shielding as a secondary benefit."
] |
[
"Has the universe existed long enough for entire galaxies to have been born and died?"
] | [
false
] | Certainly it has happened with stars, but could an entire galaxy have formed and died out in the time since the big bang? I vaguely feel like the universe isn't old enough for that yet, but I'm not an astronomer. (this question inspired by a meme I saw that said "Cthulhu saw galaxies flare into life and fade from view ... | [
"Define died out. Do you mean every star within them gone out? If that's what you mean, then no. All galaxies will invariably contain Red Dwarfs and White Dwarfs. Both stars have live spans that are so massively long, they will not die for what is conceivably, forever.",
" ",
"Red Dwarfs livespans are nearly 1-... | [
"Actually yes, in the beginning of the universe the first stars to form where suppermassive, meaning they burned their fuel much faster and living shorter lifes. And what makes a galaxy “alive” is it having constant star formation, but due to this fast fuel burning the gas that composite galaxies and could pottenti... | [
"The scientists studied an image of the oldest light in the universe to confirm its age of 13.8 billion years. This light, the \"afterglow\" of the Big Bang, is known as the cosmic microwave background and marks a time 380,000 years after the universe's birth when protons and electrons joined to form the first atom... |
[
"What kind of an immune system did past species of the genus Homo have?"
] | [
false
] | To clarify, I'm not specifying the exact species (e.g homo habilis), because I don't know whether we even have such information. But if we do, any kind of it would be nice to hear. About the immune system: if it is known, how did it differ from the one the humans now have? | [
"You can put a boundry on it, at least, by looking at our relatives. ",
"It would be at least as similar as what we see in chimpanzees. There are differences in response, but the overall architecture of the immune system is the same in both chimpanzees and humans. They respond to certain pathogens more, other pat... | [
"This is a complete unknown, as no details of any organism's immune system survive in fossils. The best one could do is to assume our ancestors had the immune system characteristics that are shared among the modern Great Apes, but this would of course be just an assumption and not actual information."
] | [
"Well, that's essentially what I said. My phrase \"complete unknown\" is a bit overstated, but in the realm of human evolution it's alarmingly common for pure speculation to become accepted as unimpeachable fact."
] |
[
"Did CFCs cause the ozone hole over Antarctica? Is the Montreal Protocol making it better?"
] | [
false
] | I heard that maybe we got this one wrong. That CFCs aren't directly responsible for the hole in the ozone layer. With some 25 years hindsight what do we know now that we didn't then. | [
"NASA has a lot of good ozone hole measurement data here:",
"http://ozonewatch.gsfc.nasa.gov",
"That data shows that the growth of the ozone hole has effectively stopped as a trend (with fluctuations yearly based on other atmospheric conditions).",
"The CFCs already released in the atmosphere will take some t... | [
"This is askscience not askreligion I should be able to question everything. :) Plus there's nothing wrong with seeing if we got it right,",
"But the real reason is the anti-AGW guys are saying we got it wrong. It's nice to see we didn't."
] | [
"But the real reason is the anti-AGW guys are saying we got it wrong. It's nice to see we didn't.",
"AGW, or anti-AGW, that doesn't matter. Neither of those terms are representative or relevant to the better name of 'climate change.' Tacking on a political connotation to a global environmental issue is not only c... |
[
"How do satellites in Space send signals back to Earth?"
] | [
false
] | For example the New Horizons spacecraft that sent pictures from Pluto? How do they get all the way back to earth? I'm guessing it's infrared signals or something but I don't understand at all how stuff like that works. | [
"Spacecraft tend to use radiowaves for communication with Earth. New Horizons uses the so-called X-band, which is somewhere between the typical radio frequencies used on Earth and infrared.",
"Because of the distance, at least one side of the communication needs to have a powerful transmitter and a sensitive ante... | [
"Ahh so it's not so much a direct line as a big transmitter picking up data the Spacecraft has released? ",
"That's how every form of radiocommunication works. One side broadcasts a signal that can be picked up by anyone listening. With the right antenna you can focus the direction of the signal, but given a larg... | [
"Excellent, I guess I never really thought about it that much but it makes so much sense. Thanks again! "
] |
[
"Is it possible for genotypes to \"converge\" over time, as phenotypes sometimes do in different species?"
] | [
false
] | I used to be a docent in a museum, and one of my favorite things to point out on tours was a set of ichthyosaur fossils next to a picture of a dolphin skeleton, showing convergent evolution. I understand convergent evolution on the phenotypic level, but I never really thought about what's going on genetically. After so... | [
"While it would, in theory, be possible, it is extremely unlikely. For a certain phenotype there are loads of different combinations of mutations that could give rise to it. For example, say a certain nutrient needs to be digested more. It could be that the enzyme that digests it is mutated so it's more efficient. ... | [
"To expand on this slightly, selection acts on phenotype, not genotype. Similar environmental constraints may drive two organisms to converge on similar phenotypic solutions, but no such pressure acts directly on their genetics."
] | [
"This is an example of phenotype convergence, so not what the question is about. ",
"It is a very interesting phenomenon though :)"
] |
[
"Do we know the long-term health effects of plant-based meat substitutes yet, like Beyond Meat or Impossible Burger? This trend caught on rather quickly and it makes me worry."
] | [
false
] | Not that eating and smoking are the same thing, but we are only just now discovering the long-term effects that vaping can have on the lungs. We know these plant-based meat substitutes are edible and don’t cause immediate issues, but so we know they’re safe if you’re eating them over a period of time. These kinds of de... | [
"The individual ingredients have all been approved for human consumption. As far as I know, only the Impossible Burger actually uses a new ingredient, but they followed all the proper procedures and did the necessary (animal) testing to get it approved before bringing it to market."
] | [
"I believe they use ",
"leghemoglobin",
", which is similar to heme found in animal red blood cells. It gives the meat an \"iron\" taste. I heard a podcast about it here: ",
"http://freakonomics.com/podcast/meat/"
] | [
"The ingredients of these burgers are just plant-based products, that people have been eating for a long time. Of course there is a chance that one of the ingredients will be found to have some side effect in the long term, but they aren't more likely to have hidden side effects than meat. The comparison to vaping ... |
[
"Does taking a vitamin D supplement stop natural vitamin D production?"
] | [
false
] | [deleted] | [
"Probably not. Consider that vitamin D3 comes from 7-dehydrocholesterol. The sun turns 7-dehydrocholesterol into vitamin D3, but 7-dehydrocholesterol is also converted into cholesterol. All cells must produce cholesterol, as it is an integral part of the cell membrane. Any feedback regulation that would inhibit 7-d... | [
"The process that creates vitamin D also creates another important (by-)product. Thus stopping this process just because your body does not need more vitamin D would be detrimental and is thus unlikely."
] | [
"Can you explain again, like I'm 5?"
] |
[
"Coded Aperture Imaging - It can be used to localize Gamma Ray Bursts, but can it be applied to Medical Imaging?"
] | [
false
] | I recently learned about coded aperture (CA) imaging, which is a technique used in some survey sattelites to identify the location of high-energy photon events (such as gamma ray bursts). Directionality is usually established in visible light images through various optics techniques, such as focusing light using a par... | [
"The true difference between x-rays and gamma rays isn't their energy, but their origin. X-rays are defined as photons that originate from electrons, and gamma rays originate from the nucleus. Thus, for medical imaging, the difference becomes a bit meaningless. For instance, you can have a ~30 keV \"gamma ray\" ... | [
"I don't see a use for coded aperture imaging in medicine. The main reason is that there is no reason to use coded aperture for any kind of radiation except for gamma-rays. And gamma-rays will make for an extremely poor medical imaging technology. X-rays are used for medical imaging because human soft tissue is tra... | [
"Well, that is the nuclear physics definition of the difference between a gamma-ray and an x-ray. The astronomy definition is that x-rays can be imaged with glancing incidence telescopes while a gamma-ray is anything above that limit (about 15 keV). In astronomy, x-ray atomic transitions and nuclear are rarely seen... |
[
"Is there a chemical or other fire type which does not require oxygen?"
] | [
false
] | Edit: on earth. | [
"Yes but you generally need a very strong oxidizers such as chlorine trifluoride. Since fire is just rapid oxidation it can theoretically happen with any oxidizer but realistally it is rare. Also some metals will catch fire with CO2 rather than atmospheric oxygen but that technically has oxygen it it."
] | [
"Chlorine is a common oxidizer for fire. There is a classic demonstration of ",
"acetylene burning in chlorine",
". I have done this one myself. It is really fun to watch. (but the gases are quite toxic)",
"http://chemed.chem.purdue.edu/demos/main_pages/24.10.html"
] | [
"What you see as fire is a type of oxidation. While Earth with more oxygen than it should have thanks to plants and algae, most flames you see oxygen is the oxidizer. A simple example you can look up a demonstration of from the Royal Society of Chemistry public lecture \"Fire and Flames\" which is on YouTube, is co... |
[
"Question about the distribution of human vision quality."
] | [
false
] | So I was wondering, are there any studies done on the distributions of prescriptions of people. I'm sure that there has to be, if we study trends in vision quality and stuff, but I just can't seem to find any results. I'm curious what average human eyesight is, and how varied it is. Does it end up being very bi-modal: ... | [
"There's a journal called Opthalmic Epidemiology; you might be able to find something there."
] | [
"Yeah a search for \"Ophthalmic Epidemiology distribution myopia\" seemed to turn up some stuff. I'm not in the field at all, but maybe something like this is relevant: ",
"http://shileyeye.ucsd.edu/eyemobile/RefErrinLowIncCh.pdf"
] | [
"I found ",
"this",
" article (1974, but free to access) that did a survey of Egyptians' visual acuity. Page 250 has a table with distributions by acuity using a Snellen chart (they use the metric form of 20/20, which is 6/6)."
] |
[
"Why does the the cosmic background radiation have a uniform temperature of 2.7 K?"
] | [
false
] | I know that light is red shifted by traveling over cosmological distances, and the CMB was hotter and bluer in the past. What I don't understand is how it stays in thermal equilibrium as the universe expands. Does the light it come to an equilibrium temperature by interacting with matter? Does redshift change the wavel... | [
"The light is redshifted not because it has traveled, but because the universe has expanded.",
"In the early universe, the photons were in thermal equilibrium with matter. When the universe was about 375000 years old, atoms formed, and the light ",
", meaning that, generally speaking, it was no longer regularly... | [
"Generally, in an expanding universe, a thermal distribution of blackbody radiation stays thermal, which was shown by Tolman in the 1930s.",
"So the photons got into equilibrium when they and matter were all interacting. Then the photons decoupled and were locked into a thermal distribution. The expansion of th... | [
"Just to elaborate on ",
"/u/fishify",
"'s great answer, a thermal spectrum of light has the following energy distribution function:",
"f(E) ~ 1 / (e",
" - 1)",
"where T is the temperature, k is Boltzmann's constant, and E is the energy of a photon (light particle). As the universe expands, the energy re... |
[
"Posting this here in the hopes a marine biologist or someone knowledgable can answer this. (x-posted from r/AskReddit originally from r/Pics)"
] | [
false
] | [deleted] | [
"I think in fact, the correct term is 'squid giant axon,' which clarifies its meaning quite a bit."
] | [
"Fish are jawed vertebrates. They have myelinated axons as well!",
"EDIT: ",
"You might find this interesting"
] | [
"Just to clarify (because I once had this misconception), when we say ",
"giant squid axon",
", one should read it as \"giant\" squid axon, not \"giant squid\" axon. It is a large axon from a certain type of normal-sized squid, ",
" a normal axon from a giant squid. Although that would be awesome."
] |
[
"Has modern medicine influenced natural selection at all?"
] | [
false
] | null | [
"Most evolution and human disease doesn't quite work that way. Most genetic diseases are either multigenic or recessive.",
"Let's start with recessive genes. Take an example cystic fibrosis. Among those of European descent, the carrier rate (one copy of the mutation) for the cystic fibrosis mutation is around 1 i... | [
"so, just to clarify, even though the genes are getting passed on because these people are now able to live, it doesnt necessarily increase the amount of genetic defects because the gene pool is so large. kinda like putting a needle in a haystack, yeah, the needle is there, but youre not likely to get stuck? "
] | [
"Yes I think that's mostly true but I got it a bit wrong. But as marblar pointed out, over the long run, modern medicine could affect disease frequency because you are lowering the negative selection coefficient in a formula called the mutation-selection balance. New mutations arise spontaneously. If these are bad,... |
[
"Last year, CERN released 300 terabytes of Large Hadron Collider data. Why does particle physics use so much data?"
] | [
false
] | [deleted] | [
"To give an example of just one small part of ATLAS (which is only one of several detectors): The Pixel Detector consists of 1744 modules arranged in cylindrical layers around one of the collision points. Each of those modules contains 47,000 pixels (so 80 million total). The beams are manipulated so that they coll... | [
"I'm not sure about the Hadron, but I used to work in X-ray crystallography which is kind of similar in terms of data collection. In our systems we would mount a single crystal which held an unknown protein. The sample would be mounted on something that rotated 360 degrees while an x-ray beam was shot at it and a d... | [
"All of the pixels are not collecting or being exposed to data 100% of the time."
] |
[
"How does quantum field theory explain spin?"
] | [
false
] | I have tried to find the answer to this online, but I can't seem to find a satisfying answer. | [
"I'm not saying that your historical overview of the Dirac equation is incorrect, I'm saying that attributing spin to relativity is incorrect. Spin is a consequence of rotational invariance. You can have relativistic particles with or without spin, and non-relativistic particles with or without spin. ",
"Relativi... | [
"I'm not saying that your historical overview of the Dirac equation is incorrect, I'm saying that attributing spin to relativity is incorrect. Spin is a consequence of rotational invariance. You can have relativistic particles with or without spin, and non-relativistic particles with or without spin. ",
"Relativi... | [
"Spin arises in non-relativistic quantum mechanics, so this answer is not correct. "
] |
[
"When someone is critically injured, does keeping him/her awake & alert really help prevent death? If so, why?"
] | [
false
] | Is it just a psychological reaction by others that sleeping is like death, so preventing sleep will prevent death? Or is there a medical basis - perhaps being awake improves vital signs over being asleep? | [
"No. In fact, the critically ill are often medically sedated for a number of reasons, depending on the specific circumstances. "
] | [
"This has been asked before if you want to do a search.",
"The answers from EMTs were along the lines that it's much easier to assess and ask questions of conscious patients."
] | [
"Actually the person is periodically awoken to assess for things that wouldn't be noticed in a sleeping patient - blurred vision, impaired speech, dizziness, nonreactive pupils, headache, confusion etc. ",
"A person may initially present with a brain bleed or swelling that has no symptoms and without a scan you w... |
[
"Do people with better reaction times experience the passage of time slower?"
] | [
false
] | null | [
"That's a great question. Although, this doesn't answer your question directly, there was an experiment performed asking a similar question.",
"When jumping off a building / bungee jumping, time feels to be moving slower. The hypothesis for this experiment was that you would be able to read a number flashed at ... | [
"Bah, beat me too it. ",
"Here",
" is the study.",
"This",
" article is a pretty good description of different ways our perception of time changes. "
] | [
"I'd like to know how you would measure how people experience the passage of time (not aimed at OP)?"
] |
[
"Does the ISS need course corrections due to people moving around inside, and if so how frequently does it happen?"
] | [
false
] | null | [
"There a couple important points to make here. Absent of external factors, there is nothing you can do on the inside of closed vessel in space that will result in any long-term change in the velocity. Essentially, momentum conservation means that you pushing off the wall at some point is exactly cancelled by you ru... | [
"No. The people moving around inside will not change the location of the ",
"center of mass",
" of the system: the weighted-average position of the station and its contents will be unaffected.",
"We can even do the math! There are ",
"6 astronauts",
" on the ISS right now, with a total mass of about 400... | [
"No. Astronauts inside or otherwise attached to the ISS must obey Conservation of Momentum and thus any motion (i.e. linear or angular momentum) imparted on the ISS by an astronaut will be cancelled out a short time later when the astronaut must impart an opposite force on the ISS to stop their original motion."
] |
[
"If a sealed jar of air was brought up to low Earth orbit and opened, would the air eventually fall back into the atmosphere?"
] | [
false
] | [deleted] | [
"The only thing that keeps our atmosphere from blowing away with the solar winds, aside from gravity's contribution, is our magnetic field. It blocks the solar winds.",
"An excellent refutation of this idea is the planet Venus, which has a thicker atmosphere than Earth's with no magnetic field. Mass of the Earth ... | [
"Venus has a strong ionosphere and an induced magnetosphere protecting its atmosphere. "
] | [
"Nope, just in front of the bow shock if we are considering the magnetic field, and the bow shock is 90,000 km from the surface, or about a fifth of the way to the moon. "
] |
[
"Which side tips?"
] | [
false
] | I have found following image on some image board and it got me thinking. For the sake of this question lets asume that the scale would be level with the balls removed e.g. there is same amount of water, the beaks are identical, and the scale is level on it's own. My idea: The buoyancy of ping-pong ball won't affect the... | [
"Since the steel ball is suspended, its mass does not affect the system. ",
" It's suspended, but some of its weight is supported by the water. In fact, it adds a force exactly equal to the weight of the water it displaces. This can be seen by noting that the force it exerts on the string is reduced by exactly ... | [
"Since the steel ball is suspended, its mass does not affect the system. ",
" It's suspended, but some of its weight is supported by the water. In fact, it adds a force exactly equal to the weight of the water it displaces. This can be seen by noting that the force it exerts on the string is reduced by exactly ... | [
"One slight correction: the buoyancy of the ping pong ball does not affect the weight of the left side.",
"As far as gravity is concerned, that string in the left beaker is irrelevant (other than it's weight of course, let's assume the string itself is weightless). The weight of the left side, regardless of what... |
[
"Magnetic Molecules?"
] | [
false
] | Magnetic materials have magnetic properties creating a north and south pole, correct? And, if you break a magnet in half, it makes two magnetics, each with their own north and south poles, right? And this just keeps going for any number of breaks you make? What about down to the molecular level? If I separate a single ... | [
"This isn't actually fully known, and it's quite relevant as hard drive bits become smaller and smaller. At IBM they showed that magnetic domains could form in clusters of just 12 atoms: ",
"http://www.research.ibm.com/articles/madewithatoms.shtml#fbid=81IDhyf7B9w"
] | [
"Probably, yes. If you get down to it, the reasons things are magnetic is because of rotating charges. A single rotating charge (like an electron) will produce a magnetic field with both north and south pole.\nNow there may be some exotic monopole out there, but it certainly isn't well known- and you won't get it b... | [
"That makes sense. I wasn't sure if the magnetic fields were created by subatomic particles or the interactions therein, so that's good to know."
] |
[
"Is there any research to verify the existence of the \"Ben Franklin effect?\""
] | [
false
] | The is a popular trope on the internet but is there any actual research that verifies this as an actual phenomenon or is this more of a popular idea? | [
"There's definitely research to support aspects of this effect. For instance, lots of research has demonstrated the ",
"foot-in-the-door effect",
", wherein you are more likely to do a bigger favor for someone if you have already agreed to do a smaller one. ",
"As mentioned by another comment in this thread, ... | [
"It is mentioned in ",
"59 seconds",
", which is fully sourced, so there must be. I don't have my copy here, I will try and remember to post a source when I get home."
] | [
"What is the connection between these two? ",
"Please avoid posting links without explanation / answering the question."
] |
[
"If I'm stranded on an island, how long can I live off of a diet consisting of only coconuts?"
] | [
false
] | I know coconuts are very healthy, but how long can I live off an indefinite amount of only coconuts. Assume no fresh water is readily available outside of the coconuts so all you have is coconut meat and milk. How long do I have? | [
"Coconuts are a pretty complete protein source and are a good source of fats and carbohydrates as well. However, they are severely lacking in Vitamins A, K, B6, and B12. Deficiencies in these vitamins can cause ",
"pernicious",
" or ",
"microcytic",
" anemia, ",
"loss of ability to fight infections",
",... | [
"Actually the body stores B12 to prepare for long periods of going without it, so some people have ingested no B12 for 5-7 years before symptoms developed. I'm not sure if the same is true for B6...."
] | [
"Pernicious anemia isn't caused by B12 deficiency. It's an autoimmune process against parietal cells and intrinsic factor, which is required for absorption of B12. Pernicious anemia results in B12 deficiency, not the other way around.",
"B12 deficiency causes megaloblastic anemia (macrocytic not microcytic). B12 ... |
[
"Could a zombie virus be created? Also, could a zombie run purely on brain function like it is potrayed in the movies/television?"
] | [
false
] | [deleted] | [
"Not to mention zombies would be extremely easy to kill, probably easier to kill than a healthy human considering the wear and tear it has to suffer. "
] | [
"There are several known diseases/parasites that cause major behavioral changes in hosts.",
"Rabies",
" makes hosts more aggressive, allowing the virus to be transferred through saliva during a bite.",
"The ",
"lancet liver fluke",
" causes host ants to put themselves in great danger of being eaten by gra... | [
"Rabies often don't make humans aggressive though."
] |
[
"Will a black-painted surface cool faster or slower at night compared to a white surface?"
] | [
false
] | I know sunlight is better absorbed by black surfaces, and they warm up faster and hotter in the daytime. But what effect (if any) would color have on nighttime cooling? | [
"Radiation emitted by an object in this case, the so-called blackbody radiation, depends only on the temperature of the object. ",
"It doesn't ",
" depend on the temperature - it also depends on the emissivity, which is very important in the case of discussing an exterior coating of paint.",
"White paint is u... | [
"If you look up Emissivity on Wikipedia, you will see that color is not a good indication of ability to absorb or radiate infrared radiation, but, yes different materials do \"cool\" or emit \"heat\" at different rates. Here's an excerpt...",
"With the exception of bare, polished metals, the appearance of a surfa... | [
"As ",
"u/Astromike23",
" mentions, there is a difference. An object radiates energy proportional to the blackbody spectrum times the absorption spectrum, as described by ",
"Kirchhoff's Law",
". ",
"Black paint and white paint are tricky because at normal temperatures the blackbody curve peaks in the inf... |
[
"Do earthquakes affect the planet's orbit?"
] | [
false
] | Wouldn't Newton's third law suggest that no amount of planetary wriggling could cause it to move in space? | [
"If you mean \"Can an earthquake change Earth's orbit around the sun,\" the answer is a flat-out, resounding \"No.\" It would take either a collision with another planetary-scale body of similar mass, or a massive rocket engine firing from the surface.",
"However...an earthquake ",
" (and even ",
", in the r... | [
"You're right in saying that Newton's third law suggests this. Newton's first law is more useful in this case: an object stays at rest/in motion unless acted on by an ",
" force. They leave external out most of the time. Since earthquakes are internal to Earth, they cannot cause the orbit to shift."
] | [
"Just to clarify a part of this. You do not need a collision to alter Earths orbit around the Sun. This happens naturally and all the time by gravitational interactions (such as resonances and tidal effects)."
] |
[
"How exactly does this screwdriver trick work?"
] | [
false
] | It looks fake, but I hear that many other mechainc have done the same thing. Anybody know how it happens? | [
"This is an example of the ",
"Coandă effect",
". Basically, the air flow tends to be attracted to nearby objects, and vice versa. It's a bit hard to explain, but the change in momentum of the air stream bending around the cylinder (screwdriver) balances the momentum of the object in the air stream, causing it ... | [
"It uses the ",
"Coandâ effect",
". A jet of air is attracted to nearby surfaces, and tends to follow the shape of the surface. ",
"In the screwdriver trick, the air follows the curved top of the screwdriver, being diverted in a downwards direction. Since the air is \"expelled\" downwards, it imparts an upwar... | [
"Never seen this before, but it doesn't look fake to me. It looks like he's shooting compressed air at just the right angle on the molded handle to both keep it spinning and balance it. Basically like spinning a basketball on your fingertip, but with the added element of the angle of the handle and the weight distr... |
[
"Just had an idea for a night readable e-ink reader (without a standard backlight or lighted cover)."
] | [
false
] | So, a while ago I bought my wife a Kindle 3G. She loves it and I think it's pretty cool as well. I bought the lighted leather cover, and it works great, but I was wondering about the ability of having the text be illuminated internally - not with a backlight per se, but somehow lit without using a light shining on th... | [
"I assume there would be mechanical difficulties with combining screen types that way. But in theory, yes, it can be done."
] | [
"I think this is a great idea, though you are probaly not the first one to think about it, it's highly likely very impractical to make. "
] | [
"Yeah, I just had to get it out in case I forgot it. "
] |
[
"Viral spread in marine environment?"
] | [
false
] | How do viruses spread in marine environments? After reading about the morbillivirus causing the increase in dolphin beachings and deaths, I was wondering how a virus like this might spread in a marine environment. | [
"Understanding aquatic disease is in three steps: 1) you have to have an environment suitable for the pathogen, 2)you have to have a susceptible, compromised/stressed individual, 3) you need the right pathogen. When all three are positive, then disease is highly likely. If one is negative, then you have a very l... | [
"Multiplicity of infection is an important concept to this as well. ",
"One virus is not likely to cause an infection due to probability of it infecting, not being killed by innate immune response, and not being cleared too quickly before enough virus are produced. So just because 1 particle is floating around d... | [
"One lesser appreciated role of viruses in the ocean is the Microbial loop. Basically, bacteria are constantly uptaking carbon and being killed by viruses in the open ocean. Quite a lot of material gets cycled through this loop over and over again, occasionally getting diverted up the food chain to copepods and f... |
[
"What do we know about employee self-management and work motivation?"
] | [
false
] | I can find a lot on how self-management or employee participation in decision-making in private firms affect productivity and health, but are there any studies that have attempted to measure how the motivation to work is affected by less hierarchical organization structures? Also, what do we know (from experiments or o... | [
"Take this post with a grain of salt, I don't keep up with the latest research in I/O psychology. With that said;",
"There's been ",
"some research",
" suggesting that employee participation ",
" significantly alter motivation - the \"Moderators\" subheading of the paper I've linked to discusses the studies... | [
"There's also a ",
"neat animation",
" done of the same guy's talk"
] | [
"There's a neat TED talk on why incentives don't work.",
"Link"
] |
[
"Do other elements naturally occur in multiple configurations in their pure form, the way carbon does?"
] | [
false
] | Do other elements naturally occur in multiple configurations, the way carbon does? Not just phases. Pure, solid arbon naturally occurs as and graphite, for example. I realise it bonds more generously than most elements, but do are any others diverse like this? | [
"do you mean like allotropes?",
"Carbon can have several allotropes including buckyballs, graphite, and diamond, and more. ",
"http://en.wikipedia.org/wiki/Allotropes_of_carbon",
"Other elements can exhibit allotropy",
"http://en.wikipedia.org/wiki/Allotropy"
] | [
"Almost all elements can take on a variety of configurations of pure elemental forms. (Perhaps the Noble Gases are an exception, as they're unable to form bonds under common conditions.) Elements like phosphorus and sulfur take on many structures, but you might not encounter them every day. A better example would b... | [
"Exactly what I was looking for, thanks! I appreciate the links."
] |
[
"Before methods of starting a fire were discovered, was the only source of fire from lightning?"
] | [
false
] | thoughts? | [
"You mean the only human-used source, or only source in nature?",
"Lava occasionally starts brushfires."
] | [
"http://en.wikipedia.org/wiki/Andamanese_people#Culture",
"\nPeople in the Andaman Islands kept fire going from lightning for thousands of years."
] | [
"Natural things that can start a fire:",
"Lightning is by far the most common."
] |
[
"What happens to ants and their nest when it rains?"
] | [
false
] | null | [
"Water diffuses into the soil. Nest tunnels are surrounded by soil, so as water moves down through the soil, even if it drips into a chamber/tunnel, it will eventually hit soil again and diffuse. If the water table rises it can flood the deepest tunnels, however, ant nests are usually quite large and have plenty ... | [
"Some various articles about different aspects of my explanation, nothing incredibly specific, really.",
"http://link.springer.com/article/10.1007/BF02223951#page-1",
"\n",
"http://web.archive.org/web/20060524210928/http://wwwrcamnl.wr.usgs.gov/uzf/unsatflow.html",
"\n",
"http://link.springer.com/article/... | [
"Fire ants create a float simply by linking their bodies together. The raft floats on the surface until the waters recede. Here are a couple of pictures.",
"Raft",
" floating in the water. ",
"Bridge",
" across two land areas. ",
"Pressed",
" down to show how buoyant the float actually is.",
"Not all ... |
[
"How complete is our knowledge of any particular single cell? Can we build an atom-for-atom model of a living cell?"
] | [
false
] | I was reading an article about aging that mentioned a class of proteins who's function in cells is still unknown. This surprised me as I had kinda assumed that we had a pretty perfect knowledge of the structure and function of at least some cells. I had believed that we could break out the little plastic atom sets and ... | [
"Yeah we are constantly trying to solve more structures and new things are being added to the ",
"protein data bank",
" all the time. It's hard to make a prediction about when something like this would be available though. A lot depends on how accurate you want the model to be. Take a quick look at how resoluti... | [
"We can get close to replicating large scale function of simple cellular organisms. Stanford had a project a couple of years ago simulating a single cell of ",
" but this is largely a simulation of intracellular activity. It took around 1GB of data for a single cell, and took around 12h to simulate one replicatio... | [
"There are several technical problems. A cell contains an incredible number of atoms, so even if you do (relatively) simple classical Newtonian mechanics you would need a fearsomely powerful array of computers to process all the interactions. Such simulations are called molecular dynamics simulations and even simul... |
[
"If we could theoretically break the speed of light, would we create a 'light boom' just as we have sonic booms with sound?"
] | [
false
] | [deleted] | [
"In media such as water where the speed of visible light is less than its speed in a vacuum, charged particles moving faster than the local speed of light will produce a cone of radiation called Cerenkov radiation, which gives nuclear reactors their characteristic blue glow."
] | [
"What makes the visible light slower",
"The current best-accepted explanation goes something like this: light traveling in a medium couples to vibrational modes (and other types of excitation modes) within the medium, and ceases to be a massless photon but rather becomes a type of particle called a ",
"polarit... | [
"What makes the visible light slower",
"The current best-accepted explanation goes something like this: light traveling in a medium couples to vibrational modes (and other types of excitation modes) within the medium, and ceases to be a massless photon but rather becomes a type of particle called a ",
"polarit... |
[
"how would Proton decay work?"
] | [
false
] | I've read that proton decay is handled by x and y bosons, but I don't get how. They have color charge and weak isospin so I assume they act on a single quark, bu what happens to the other quarks, and why can the x and y decay into two quarks despite only having one color charge? | [
"The X and Y bosons you speak of are part of a Grand Unified Theory (GUT). We have no evidence that they exist, and experimental data shows that the proton is stable on timescales exceeding the age of the Universe, so no one has ever witnessed one decay.",
"That being said, many theoretical physicists consider GU... | [
"From that perspective it is, but i wanted to emphasise the point that it is a highly non-trivial process to get rid of proton decay in susy models. It actually gets worse if you include other problems like the mu-problem. Additionally you can potetially run into problems with cosmological history because of domai... | [
"That's the gist of it. Proton decay is also possible in supersymmetry (if you include baryon-violating interactions), but instead of X/Y bosons it's the squarks that mediate the decay. People impose something known as R-parity in order to get around this.",
"People all the time say that R-parity is enough to pre... |
[
"How does a virion assemble itself so perfectly in an infected cell?"
] | [
false
] | null | [
"The first thing to know is that almost all viruses are actually very bad at assembly. There are two ways to measure the quantity of virus in a sample: you can do qPCR - a way to quantify how much of a specific sequence there is (in this case you’re quantifying viral genome copies) and you can do a plaque assay - a... | [
"Oh thanks for your input! Is it possible for viruses to accidentally pick off certain parts from the host? And in a way mutate because of this?"
] | [
"Non-enveloped viruses vary, some have a tiny capsid that don’t allow for any extra cargo but it’s very very hard to rule out that a host protein or two hitch a ride. Enveloped viruses typically pick up a bunch of host proteins in the tegumen - the space between the lipid membrane and the capsid - and carry those w... |
[
"How does antibody treatment work with COVID-19?"
] | [
false
] | My issue is the following: IV administered IgG mixture does seem to work in animal models and in patients. The question really is: does it work on the lung surface? If it does, how? Any papers I have seen suggested that very little IgG reaches the mucosal surface, as the FcnR transport "outside" is not very effective; ... | [
"IgA is only one layer of defense. It is important in the initial acquisition of an infection because of its action at mucosal surfaces. Although IgG isn't as good at getting to mucosal surfaces, it plays a role in preventing the virus from further replicating and spreading. It is even present in mucosal linings to... | [
"It’s a common misconception that the IVIG is used to fight the virus.",
"IVIG attaches to virus particles throughout the body, which reduces the amount of virus the body’s own immune system sees. This then has a major role in downregulating the strength of the body’s immune response.",
"In conditions of hyperi... | [
"a bunch of things point to fake poster with no history and something being off. a physician would normally say physician rather than doctor and would not say «prescribed it». The descriptions are simplified and inaccurate with weak theories put in as facts. ",
"source: am physician scientist, two immunolog... |
[
"What is this perfect arc of discolored peel from stem to navel on my orange?"
] | [
false
] | I bought a bag of navel oranges, and one of them has a . The discolored area starts as a narrow arc at the stem of the orange, broadens over the meridian, and ends at a wider arc around the navel. I think it's too precise to be dyed. Why did it grow that way? | [
" Citrus fruits are segmented on the inside. Those segments develop from a part of the flower called the carpel. Part of the carpel is the ovary (female reproductive bit). The ovary wall is what actually forms the rind of this fruit. The rind is actually made up of the same number of segments as the inner fruit but... | [
"Thank you!",
"I peeled across the band. ",
"Close-up shot",
". It turns out the discolored skin represents ",
" of a segment. One edge lines up with the segment edge, the other lines up (only roughly) with a fiber wandering roughly down the middle of the segment.",
"But the flesh of the segment itself ... | [
"I've done some poking around the internet and I can't find an explanation for only half of segment having the weird rind. I'm not surprised that the flesh seems normal as it is derived from a different part of the flower. For a better explanation of the 1/2 colored thing, we'll just have to wait for a botanist. (I... |
[
"How does a single vibrating paper cone produce a sound in which one can distinguish multiple tones of distinct timbre?"
] | [
false
] | I know that a quality sound system is comprised of multiple speakers which reproduce tones of different pitch but how is it possible to (imperfectly) reproduces that full range of sounds with a single vibrating membrane, or a single, continuous wavy groove on a vinyl platter? | [
"Picture that you have a sine wave on a graph. Now, add another one at half the frequency:",
"f(x)=sin(x)+sin(x/2)",
"The graph of that function is what the waveform would look like for 2 tones played at the same time, with one being twice the pitch of the other. I just used sine because it's convenient; the wa... | [
"The way speakers handle pitches is by vibrating at certain frequences. The faster it vibrates the higher the pitch.",
"A subwoofer cone can vibrate quite slowly. But the lowest frequency audible to a human is about 20Hz if iirc. The highest freq. we can hear is about 20.000 Hz, but this usually lowers as you get... | [
"As you know, sound is comprised of sound waves, which can be thought of differences the density of air travelling in a direction. Objects can emit sound by vibrating - the vibration causes the air above it to compress, increasing the density, and a sound wave is created. The pitch or frequency of the sound depends... |
[
"whats the difference nutritionally between concentrated and not from concentrate fruit juice?"
] | [
false
] | null | [
"Concentrated fruit juice started as normal juice, was somewhat dehydrated (into a thick liquid), and was later reconstituted with water. This is done because concentrate stores for longer and ships more easily. Not-from-concentrate has been in its juice form the entire time. If you have ever seen the cans/tubes of... | [
"It's also worth noting that fruit juice, concentrated or not, has very little nutritional value, and is basically just sugar water. Most of the good stuff in fruit is in the pulp."
] | [
"To be fair, by far the most necessary nutrient is calories. Micronutrients are an absolutely tiny proportion of your food. It's not at all strange that also in OJ, micronutrients only represent a tiny fraction of the product."
] |
[
"The lights turned off when I touched the light-bulb with a wet finger - why is that?"
] | [
false
] | So I was trying something random/weird. After washing my hands, I touched the light-bulb in the bathroom with my wet index-finger. Then, suddenly and silently, the lights went off. It's this type - . | [
"I have an explanation for you. I think your bulb isn't completely screwed in, so it barely makes contact. When you touched it, you may have moved the bulb enough that it broke the connection, thus turning it off. I think your finger being wet was just coincidental."
] | [
"Is it possible the bulb was barely screwed in? ",
"Many times when people install light bulbs with the switch on, they stop turning when the bulb lights up. But this doesn't get the bulb screwed in tightly, so bumping or touching the bulb can make it appear to go out when it actually just disrupts the connection... | [
"This seems like a coincidence to me. Did the bulb work afterward? Did all the other lights also turn off?"
] |
[
"A question about ice interact with water."
] | [
false
] | If you have one Cubic meter of ice at -10°C and one Cubic meter with water at 10°C. If These two blocks interact with eachother will the ice gain more ice or will the water gain more water? (There is no other considerations) | [
"The math is easier if you use mass instead of volume. but to estimate...",
"according to this site:\n",
"http://www.school-for-champions.com/SCIENCE/heat_ice_steam.htm",
"the specific heat of water is 1.0 cal/g degree C",
"the specific heat of ice is .5 cal/g degree C",
"for 100 grams of ice changing tem... | [
"Not even close. You neglected the heat of fusion (the energy needed to break apart the ice lattice to make water), which is 334 J/g."
] | [
"Not even close. You neglected the heat of fusion (the energy needed to break apart the ice lattice to make water), which is 334 J/g."
] |
[
"When deep in thought, why do you \"space out\" and can't focus on things even right in front of you?"
] | [
false
] | null | [
"Attention is a finite resource. When you are devoting a lot of attention to a thought, you aren't as aware of your sensory perceptions. There are a number of what are called executive functions (",
"http://en.wikipedia.org/wiki/Executive_functions",
") that help to manage your attention and other cognitive r... | [
"is ADHD when people lack a lot of these functions?"
] | [
"I love that psychologists use the term Flow. It's so simple.",
"Flow happens when a person is immersed in something they are skilled in but are still challenged by, such as creating something with your hands, playing music, or solving a problem. Religious activities, create flow as well. ",
"\"In every give... |
[
"Would a poke with the same force as a punch do more damage?"
] | [
false
] | This question is assuming I won't break my finger/hand performing the poke. Mainly, I have no idea what determines how much harm an impact causes to a person. | [
"There are two major components of \"punching damage\", aka blunt force trauma: Acceleration and compression, which also corresponds to two types of transfers of kinetic energy: elastic collision and in-elastic collision respectively.",
"Compression is when you absorb impact energy in an inelastic collision. This... | [
"Easy way to visualize this is to go to extremes. Imagine a 20 lb weight falling on your stomach that is in the shape of a barbell weight. Then imagine the same 20 lb weight with a spike on the bottom of it falling towards your stomach. The less like a spike, the less chance of penetration."
] | [
"What baalak and ronin1066 said, and also what you said - you have to make sure your don't break or jam your fingers. For that reason these types of fists are best reserved for certain types of targets, like around the neck down to just above the sternum, or possibly the temple, sometimes the ribs if you know what ... |
[
"Relationship between most favorable energy states on a chemical and quantum level. What are the implications for origin of life?"
] | [
false
] | Hi, as far as I understand, chemical reactions occur because the atoms "prefer" to be in a lower state, energetically. Why is that so on a quantum level? Also, if all chemical reactions are trying to sustain the lowest energy state, then would that mean that DNA, is doing that as a macromolecule? (And its current incr... | [
"I think you trying to connect a lot of disparate ideas in a way that is entirely unnatural.",
"Systems tend to follow the course of lowest action, and minimize energy state for conservation of energy reasons. On the other hand, if there is enough energy present (for example from thermal fluctuations), you can sa... | [
"What I'm trying to say is that while the quantum mechanics may be negligible on a macro scale, weren't they the basis for all of atomic bonding in the first place? ",
"On the scale of an atom aren't the quantum mechanics fairly important? \n(The orbital theory of the atom and hybridization states.) ",
"The fir... | [
"why are you wanting to bring quantum into this? Why not use a more traditional chemical approach?",
"Sure, you can talk about quantum mechanics in a DNA context, but things get needless complicated almost instantly. One analogy would be trying to swat a fly. Sure, I can talk about getting rid of a fly using a l... |
[
"Are people with higher IQ more suscetible to depression?"
] | [
false
] | null | [
"Just looking at raw correlations, higher intelligence would seem to be associated with a lower overall risk of mental illness. ",
"Lower IQ score was associated with increased risk for schizophrenia, severe depression, and other nonaffective psychoses, but not bipolar disorder.\" ",
"[1]",
"Lower childhood I... | [
"From the opposite direction, low IQ correlates with early lead exposure, fetal alcohol spectrum disorder and a diverse range of congenital defects which all broadly adversely affect cognitive functions, including emotional regulation."
] | [
"In a way. Mostly what I hear of is kids with high IQs end up having so much pressure put on them that they “burn out” and become depressed due to feeling like their letting everyone down. ",
"But otherwise i wouldn’t say their more susceptible just because of their higher IQ. It has a lot more to do with the bra... |
[
"How does the immune system manifest itself at the mouth level?"
] | [
false
] | There are no white blood cells to fight off oral bacteria, so is there any antibacterial secretion in saliva? | [
"There are ",
"IgA",
" antibodies that line the mucosal layer of the mouth. This, along with ",
"lysozyme, lactoferrin, and peroxidase",
" are the primary molecules involved in the mouth's immune system.",
"When this system doesn't work properly, such as those with HIV/AIDs or people who take corticoster... | [
"And don't underestimate the mechanical cleansing provided by tongue, chewing, and swallowing. That helps to eliminate many microbes by sending them to the gastrointestinal tract. It is often forgotten that immunity is very much a numbers game, and diluting the contents of the oral cavity by continuous salivation a... | [
"is there any antibacterial secretion in saliva?",
"Yup.",
"You produce lysozyme, an enzyme that targets the peptidoglycan layer in bacterial cell walls, immunoglobulin A, lactoferrin, and a few other proteins that have antibacterial as well as antiviral and antifungal properties."
] |
[
"Is it possible to have two different dreams in the different hemispheres of the brain?"
] | [
false
] | null | [
"Yes and no. I'll start off with why not. The two hemispheres of the brain are connected at numerous points, notably through the corpus callosum, anterior commissure, and hippocampal commissure. The dense connections between the two hemispheres makes it almost impossible for something (real or imagined) to affect o... | [
"I agree that due to the myriad connections between the two hemispheres, the idea of dreaming different simultaneous dreams in each hemisphere is far-fetched. ",
"As for split-brain patients, remember that the brainstem is not separated in a split-brain patient, so the origin of PGO waves, the pons, is connected ... | [
"As we don't know what dreams are, it would be difficult to say - however I suppose people suffering from \"multiple personality disorder\" logically might indeed suffer from this syndrome. However we don't really know exactly what part of the brain it is that creates dreams, all we can do is watch people who are d... |
[
"How do black holes get larger?"
] | [
false
] | When an object moves towards the event horizon of a black hole, it experiences increasing time dilation from our perspective. If it takes an infinite amount of time for matter to "cross" the event horizon then how can a black hole grow in size in any meaningful time period? Wouldn't all the new matter just run into the... | [
"The cores of black holes are, essentially, raw energy (sort of like the Big-Bang's theoretical singularity) held in place by seemingly impossible gravity wells",
"It's probably best to not talk about the nature of the singularity because we literally dont have models for it without quantum gravity. Suffice it to... | [
"The cores of black holes are, essentially, raw energy (sort of like the Big-Bang's theoretical singularity) held in place by seemingly impossible gravity wells",
"It's probably best to not talk about the nature of the singularity because we literally dont have models for it without quantum gravity. Suffice it to... | [
"Quasars man. One of the many things that could end all life as we know it with absolutely 0 warning. "
] |
[
"How is sea level and elevation determined?"
] | [
false
] | [deleted] | [
"It's pretty far from trivial actually, if you get right down to it. Let's start with ",
"this picture",
". All the features are of course exaggerated but it illustrates several interesting points. ",
"First the dashed green line (labelled 2). It's the reference ellipsoid. A kind of simple mathematical model ... | [
"There's more than one way. The easiest is air pressure. But other more sophisticated methods involve using GPS to tell you how high you are from the reference ellipsoid, or if you want even more accuracy, the height from the geoid. But (consumer) GPS units don't have geoid data built in to them, so you'd have to... | [
"It's a really good question; I do know it's based on atmospheric pressure, although I have no clue on the formula used to get the Worldwide Mean Value."
] |
[
"Does widespread immunity decrease virus mutation rates?"
] | [
false
] | With ongoing news about mutations to the covid-19 virus (and potential impacts to vaccine programs) I'm curious what the relationship between the level of population immunity and mutation rate is. It would stand to reason that lower infection rates -> fewer opportunities for mutation -> greater long term vaccine effica... | [
"Iirc the logic you stated is correct. Because the virus does not transmit as readily it does not have as much opportunity to mutate as it doesn't get exposed to as much in the few hosts it has. This isn't to say that it can't mutate, just that the likelihood of it doing so is lower."
] | [
"It would stand to reason that lower infection rates -> fewer opportunities for mutation -> greater long term vaccine efficacy",
"Generally, yes. To make things worse, if you have many vaccinated people getting exposed to the disease then mutations that avoid the vaccination or make it less effective are heavily ... | [
"Your logic is correct! Fewer bodies infected with the virus leaves fewer opportunities for the virus to go through its replication cycle and thus, fewer opportunities to mutate. However, mutations could still arise in one or two infected people, because viruses are so tiny and create hundreds of thousands of proge... |
[
"Is indefinite and undefined the same thing mathematically?"
] | [
false
] | As in an indefinite amount of times or an undefined amount of times? | [
"Do you mean indefinite integral? That's the only indefinite math term I can think of. In either case, indefinite and undefined are two different things. If you meant indefinite number in the linguistic sense: an indefinite number is one that is simply vague or undefined, such as a bunch of chips. There is a real a... | [
"Yeah that's a good way of looking at it, but if you can't chop it and get nothing how can we chop it and get less than nothing? e.g. 4 / -2 = -2"
] | [
"think about it in terms of physical objects if the intangible concepts are confusing.",
"if you are trying to send gallons of water down a pipe (for some random reason) between people, from me to you is positive, and from you to me is negative (from my perspective). say i need to send you 10 gallons of water di... |
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