title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Botulinum toxin has a LD50 of about 1 ng/kg in humans. How can such a minute amount cause the entire human body to shut down?"
] | [
false
] | null | [
"Botulinum toxin is a protein with catalytic activity. This means that one molecule of toxin, if it gets to the right place, can cause a lot of damage. It's not a \"one and done\" kind of toxin where one toxin hits one target and that's it; it can hit multiple targets sequentially. Furthermore, it hits a particul... | [
"The quantity discussed above is the LD50, so with half a kilogram you would kill exactly half the world population."
] | [
"I think he means few grams would kill ",
" people. ",
"Well perhaps more then a few. Using 0.00000007g per person and a world population of 7.114 billion (according to wikipedia), Half a kilogram (497.98g) would be enough to kill every single person on the planet."
] |
[
"Are bird songs learned or built into the birds DNA?"
] | [
false
] | If a bird (the type who has distinct recognizable calls) is hatched/raised in isolation, will it still know how to do it's distinct bird song? Or are these songs always learned and just passed down generation to generation? | [
"I have a coworker who studies bird song, and at least in the species he studies, learning songs is an important component. He uses it as a model for learned human speach. The ability to sing is heritable, but singing ",
" is learned, just as children can babble but they need to hear speach to understand how to ... | [
"There are two groups of birds that sing - oscines (songbirds) and suboscines. Suboscines can also sing beautifully but their syrinx (a bird's equivalent of our larynx) is different. Songbirds (oscines) have the ability to produce two different notes simultaneously but suboscines can't. ",
"Songbirds have to lear... | [
"In my neighborhood there's a bird in the summer that sings the first few notes from \"I'm a Barbie Girl\"."
] |
[
"Water temperature vs. pressure in a home shower"
] | [
false
] | My situation: My fiance and I had separate showers. She always turns the hot water tap up to the maximum setting, then adjusts the cold water until she is comfortable. I always turn the hot water tap up to the minimum setting at which a steady stream comes out of the faucet, then adjust the cold water until I am comfor... | [
"Fluid power specialist here. ( pneumatic mainly ). The temperature fluctuations are not directly influenced by the amount of flow; but rather seems to be that your shower is the path of least resistance for your hot water line. All fluids be it water or air will take the easier path but sometimes behave differe... | [
"Thanks for the reply. The clearest explanation of CV rating I found was ",
"https://en.wikipedia.org/wiki/Flow_coefficient",
", and based on that I get the impression that the CV rating is probably related to orifice size. If that's the case, then I guess I'm right. ",
"It also seems, based on the wikipedia ... | [
"Scientifically you should start at the beginning.",
"You should shower together, under both settings.",
"There is a chance you're describing the same thing in different ways.",
"You say you and your fiancée had seperate showers. Does that mean you are divorced or you have moved to a place where you share sh... |
[
"How could an ultra massive black hole form?"
] | [
false
] | I’ve read that solar or near solar mass black holes would form mostly from novae. And that larger black holes could be primordial, or mergers, or black holes that have eaten a significant amount of matter. These were the theoretical explanations for the first LIGO merger black holes. (Could be wrong on that one). My qu... | [
"Roughly speaking, the mass of a supermassive black hole (for our purposes any massive black hole not formed at the end stage of a large star) scales with the mass and motions of the stars in its host galaxy. The larger the galaxy, especially the larger the center part of the galaxy, the larger its SMBH.",
"We th... | [
"That’s really interesting. Thanks for your insight. ",
"Follow up questions, if you don’t mind:",
"I’ve always seen the “eats the star by ripping it apart” type animations. So it’s kind of terrifying to imagine something swallowing a star like a cheese ball. How does the tidal force scale with size(or mass I s... | [
"The more massive the black hole, the less severe the tidal forces will be on a given object at a given distance. This is because the gravitational field is directed radially (outward uniformly in all directions). So at a given distance from an object with mass, one side of you will experience gravity pulling sligh... |
[
"Is there any combination of distance, mass, and volume of two planetary bodies where one of them can look like this from the surface of the other?"
] | [
false
] | [deleted] | [
"A moon close to a gas giant would get this view of the big planet. Jupiter as seen from Io would be close. However, people often overestimate how big Jupiter would look in the sky - it would be about ~10~ 20 degrees across, or about the size of a basketball held at arm's length. It would be big and look cool, but ... | [
"Have a deep enough zoom and that could easily be the ",
"Earth's Moon",
". It is impossible to gauge the angular diameter of a pictured body without knowing the field of view of the picture itself."
] | [
"I'm guessing to get angular width of Jupiter you're taking asin(Jupiter's radius/Io's semi major axis). ",
"You need to double that. I'm getting 19.5º."
] |
[
"Why have mammals evolved to only birth one child at a time instead of laying eggs and having more?"
] | [
false
] | null | [
"The premise of the question isn't true. Dogs, cats and pigs have litters for example."
] | [
"Right you are. What if I asked then simply what's the trade off between litters and the way humans do it? Why don't twins and triplets become the norm, it would it it were advantageous trait to have, so why isn't it advantageous?"
] | [
"That sounds good! Please make a new post and someone will release it."
] |
[
"How do scientists determine the exact shape of complex proteins in lab?"
] | [
false
] | I assume it would be impossible to cut them into layers and examine cross-sections under an electron microscope. Also I gathered that protein folding problem still needs such immense processing power that makes it impractical to come up with the shape of a complex molecular like Ribosome just by knowing its amino acids... | [
"As a structural biologist, this is right up my alley. ",
"As people have already mentioned x-ray crystallography is a great way to look at atomic level details of proteins. Check out ",
"www.pdb.org",
" if you are interested in actually looking at some real protein models. ",
"Aside from crystallography, N... | [
"Absolutely.",
"Solving structures with NMR is very very difficult. This is because there is a lot of degeneracy with the data, and the signal to noise ratio is very low. Thus, experiments can take on the order of a week and are typically 3D and sometimes 4D in nature (dimensions here mean atoms referenced). In t... | [
"Yeah. Some of the more recent structures are quite impressive. I think direct detection technology allows better time resolved imaging that has led to these near atomic lev resolution structures. "
] |
[
"Why can extreme hot weather cause mass power outages/blackouts?"
] | [
false
] | Just recently in Australia we had an extremely hot day which caused a mass blackout of more then 50,000 houses. Why does this happen? | [
"The main reason is that electricity usage is highest during heat waves, because everyone's air conditioning is running at full blast.",
"There's a second less important reason, which is that fossil fuel and nuclear power plants are less efficient in hot weather. They use outside air and/or water to cool their s... | [
"I did say it's not as large a factor as the change in demand, but it's enough to worry about. US summer generation capacity is lower than winter by about 4%. Which doesn't seem like a lot, but that's a blackout for 12 million people if you don't account for it.",
"The change is also much greater than the avera... | [
"This theorem may relate well to an observed fact, which is that air conditioners can cool from one temperature to another, but at the limits of their ability to cool, it will be found that rather than cooling in an unlimited manner, they can only cool by a certain number of degrees. This specification for an A/C s... |
[
"Will the jets of Enceladus ever run dry?"
] | [
false
] | I was watching Space's Deepest Secrets and they talked about the moon Enceladus and the jets it has blasting water into space. My question is, why hasn't Enceladus run out of water? I don't normally post here so I apologize if this is a stupid question. | [
"A few things to note here:",
"Enceladus has a surface gravity of .11m/s",
" , which is about 1% of the Earth's surface gravity of 9.8m/s",
" With such low gravity, you can imagine that it takes very little force to get material up into space. Enceladus's largest jets are shooting 250kg of water vapor every s... | [
"Yes, that is above escape velocity of Enceladus (wikipedia quotes it as ~800-900km/h), however, unless it is also above escape velocity of Saturn, and the jets are in the correct direction, then Enceladus will eventually collide with the water, as it will still be in an intersecting orbit with it around Saturn. S... | [
"Our sun will not go supernova as it has too little mass. Instead, it will become a red giant that is large enough to engulf some of the inner planets (RIP mercury :'( ) and then become a nebula with a white dwarf at the center."
] |
[
"Can a drink actually be “more hydrating” than just water, or is that just made up to sell sports drinks?"
] | [
false
] | Basically title. How can something hydrate you more by adding electrolytes or salt? Surely the amount of water you’re putting into your body is the only measurement of how hydrated you can be? I’m torn between “I don’t know enough about electrolytes to question it” and generally assuming all marketing/advertisement is ... | [
"Salt, and and other electrolytes like potassium and calcium, are very important factors for hydration because they facilitate the movement of water in and out of cells. They have properties that allow them to bind to water and move it around. This is why, to be properly hydrated, you need electrolytes. The \"super... | [
"This study was done a few years ago. ",
"Which drinks hydrate best with link to actual study",
"In case you don't want to read the whole thing here are the main findings. ",
"The researchers ranked the 13 beverages they tested, from most hydrating to least over a four hour period. Here is how they rank:"
] | [
"I don't know about ",
" hydrating, but when someone sweats a lot like when playing sports the body loses electrolytes. Same thing for when someone is really sick and throwing up(or has diarrhea). Electrolytes are vital for our body to function, so drinks like Gatorade and pedialyte restore those things. If someo... |
[
"When will the Andromeda Galaxy be close enough to be visible to the naked eye? How big would it be in the night sky?"
] | [
false
] | In reference to this post/picture: . At what point in time will the Andromeda Galaxy be close enough to be visible to the naked eye, perhaps not as bright as this picture depicts it. And, how big would it be in the night sky? Thanks. | [
"Andromeda is visible to the naked eye now, in decent light conditions. It has an apparent magnitude of 3.4. It is more than six times the width of the moon in the sky, but the full diameter is not bright enough to be seen."
] | [
"No, it's visible from the northern hemisphere. In Toronto it's at zenith (strait up) at about 6pm. "
] | [
"I've personally seen it unaided from a provincial park just outside of Ottawa, Canada in Gatineau. It appeared as a faint smudge, like a thumbprint on the night sky. \nI'm sure you can find an app to tell you where and when to look from any location if you want to try to spot it."
] |
[
"Why is the Chernobyl New Safe Confinement only rated to last 100 years? What happens after 100 years pass? What determines how long it lasts?"
] | [
false
] | [deleted] | [
"I can partly answer this, the engineering side of things I have no clue.",
"The New Safe Confinement building actually contains a bunch of equipment to dismantle and process what remains of reactor 4. So hopefully in 100 years if the structure breaks down everything will be cleaned up by then. ",
"The ",
"of... | [
"It's a rating. It means that all the parts last 100 years at least and you are forbidden to use like, a screw that typically falls apart after 25 years or something. In reality lots of parts of it will easily last much longer. A big heavy block of concrete is not going to vanish into dust at midnight of the last d... | [
"What's going to be morbidly interesting for me is when they find Khodemchuk's remains under the 'pile' seen in the ",
"bottom of this photo",
".",
"For reference, that pile ",
"is this part of the plant",
". You can see how they built the Sarcophagus over it ",
"here",
" without actually removing any... |
[
"If I could very accurately measure the temperature increase of an object in a wind tunnel could I use that to calculate the drag?"
] | [
false
] | null | [
"It could be done, if the temperature of the air, smoothness of the part, thermal conductivity, and wind speed were kept very very constant. You would have to balance between a lot of variables, and it's simply easier to use more common methods."
] | [
"Technically, as long as everything else was kept constant, you could find/equate almost any variable.",
"But keeping all variables constant is hard, it's why they're called 'variables'."
] | [
"ha, I know that's not ",
", I was just making a badly worded pun on 'varies'."
] |
[
"Why are humans so incredibly resistant to stress and changes when compared to most other complex life forms?"
] | [
false
] | For example, I've heard about fish dying because the PH of their water isn't kept near perfect, or the temperature is a few degrees off. I've seen that it's not uncommon for birds to from being stressed out even for only a few minutes. Humans, on the other hand, seem to be able to weather a wide variety of climates and... | [
"Many organisms have symbiotic relationships with bacteria, it's nothing special."
] | [
"I would disagree with your statement to begin with, , also should we consider our technological advances as part of our ability to adapt or should we just consider our physiological responses?",
"I think it's all about the combination of the following:",
"I'm not going to count all of our technological advance... | [
"I think a lot of it has to do with our technological capacity. Not as in your smartphone, but I mean things like fire, clothing, and shelter building. ",
"I really have to brush up on my anthropology, but the historical picture seems to look like this: Hominids first spread out of Africa and occupied the Middle ... |
[
"What causes the difference between kinetic and static friction?"
] | [
false
] | Hola physicists (and everyone else), I was wondering (out of the blue) why moving objects once they are in motion is easier than the initial movement. Can't recall any physics teacher actually discussing it. | [
"The friction itself is caused by the interaction of elements of the surfaces essentially locking in, like teeth that fit together more or less. Mostly less when they're moving. When neither object is moving relative to each other, the rough bits will be pushing against each other in a set position. This causes the... | [
"Basically. There's an electrical component as well, but the idea's the same. As they sit on each other, they'll squish together until the rough parts fit together nicely. ",
"You can also think of it as setting a table on a carpet. At first you can slide the table around, but you know that pretty quickly your ca... | [
"Static friction almost always greater than the kinetic coefficient. This is due to the fact that no surface is perfectly flat or clean. Irregularities between the sliding surface and that of the target object causes the force needed to generate the initial movement to be (usually) greater than the force needed to ... |
[
"How much does it cost to do a whole genome sequencing of SARS-CoV-2?"
] | [
false
] | In New Zealand we do whole genome sequencing on all the positive cases we get. I was wondering how much does it cost, roughly, to do one of these tests? I found a with the detailed information on how the test is done A total of 733 laboratory-confirmed samples of SARS-CoV-2 were received by ESR for whole genome sequenc... | [
"The size of the SARS-CoV-2 virus genome is only 29,811 bases compared to >3 billion for the human genome, so the cost & time for sequencing a virus genome is way less than for a human. The cost per sequence would also partly depend on how many samples were being sequenced: sequencing one sample would require setup... | [
"To put this in persepective, I can pay ~$5000 for roughly 2.5 billion 150 BP paired-end reads. This means that if I feed in some DNA I can read 150 base pairs on either side. If I break the COVID genome into small bits I will eventually get everything, so I need to decide to what depth I want to sequence each of m... | [
"To add to this, referencing the text OP posted. The Illumina NextSeq technology is a little lowe throughput and yields about 120 Gigabases read for ~$3k which would translate to about $5.4 per genome at 25x coverage. The Nanopore minION can yield 30 Gigabases for ~$400 which would translate to about $3 per genome ... |
[
"What's the reason behind unpronounced letters?"
] | [
false
] | Started to wonder when thinking about the word 'beaucoup' (french for 'much'). There's languages where words are very long for how much is actually being pronounced. Is it just speakers being too "lazy" over a long time? But why hasn't the written word followed along? | [
"Pronunciation is historically much more variable than writing. This is because writing a word down creates an easily consulted \"record\" of how that word is to be spelled (even if not everyone agrees with you), whereas -- before broadcast media and sound recording came along -- there was no way to \"remind\" a gr... | [
"Finnish is nothing like the other three. Different group of language altogether."
] | [
"I agree with you, to a point. Swedish and especially Norwegian and Danish are similar, so much so that I've heard Norwegian and Danish to basically be alternative pronunciations of the same language, with some regional word usage variation. (Finnish is a Finno-Ugric language and totally unrelated.)",
"In various... |
[
"Does a lightning strike create a magnetic field around it for a short amount of time?"
] | [
false
] | Just an interesting thing that popped in my head today, who better to ask than this sub! | [
"Yes!",
"The EM pulses from individual lightning strikes can actually be detected at hundreds of kilometers of distance. Combining a few of such detectors with a very precise timing information (as is broadcasted by GPS satellites for free), you can get very accurate live readings of lightning strikes. ",
"Blit... | [
"Thanks for the link to Blitzortung! It's really cool. I've added it to my now growing list of global meteorological visualization apps on the web which also includes ",
"ventusky",
". Love it for watching wind patterns."
] | [
"Yes. This is the cause of all natural magnets. When lightning strikes the surface with magnetite with a suitable coercive field permanent magnets are formed nearby. Good magnets were rare. Were never found in mines."
] |
[
"How does one differentiate between species of micro-organism?"
] | [
false
] | My understanding of species are common life-forms that can reproduce together. So something like a horse is a type of species seperate to a cow, but a draft-horse and a race-horse are the same. How do you differentiate between species of micro-organism, especially since they reproduce with mitosis? | [
"My prof was all about the Phylogenetic species concept.",
"I'm a big fan of \"It's a species if I gorram well say it is!\" Keepin' it old school."
] | [
"It's tricky, but one common way of assigning species is if two bacteria or archaea have 97% identical 16S rDNA (the DNA sequence that codes for the 16S subunit of RNA). These are sometimes referred to as \"operational taxon units\" as opposed to species. "
] | [
"Yeah, that idea that a species consists of organisms which can interbreed is just one way of defining a species. It works pretty well for birds, bugs, and mammals (where lots of early taxonomic work was done), but not very well for microbes, plants, or even many kinds of fish. ",
"There are other \"species con... |
[
"Just watched a cardinal feed (regurgitate into the mouth of) a sparrow. Is this common bird behavior?"
] | [
false
] | Never seen it before is all. | [
"Are you sure it wasn't a baby cardinal? They ",
"look a lot like sparrows",
". Here's ",
"another image",
". ",
"Alternatively, it could have been a baby ",
"Brown-headed Cowbird",
"; female cowbirds lay their eggs in other birds' nests and let the other species do all the work of raising her babies... | [
"Wasn't a baby cardinal. Maybe a cowbird. ",
"Thing is, I thought I recognized the ",
"big fat sparrow",
". It has a nest in a gutter across from a window in my kitchen. Flew right back to it after getting the nosh from the cardinal. If it's unheard of, then I guess I have to get used to the fact that there ... | [
"It's always possible that you saw a truly odd behavior; stranger things have happened! However, the likeliest scenario is that the male cardinal was feeding a baby cowbird. Cardinals are often hosts to cowbirds, and that's really the only reliable example of cross-species feeding behavior that I know of... ",
"... |
[
"The Moon's orbit is getting larger by approximately 3,8 cm per year. Will this number increase or decrease in the future, or will it stay the same?"
] | [
false
] | Just recently “Terra Nova“ aired for the first time in Germany. Long story short, it takes place in the past (85 million years I think) and one of the characters said the (past) moon's orbit would increase by 0,5 cm per year. So, was that character just terribly wrong or does this number increase over time? | [
"From Wiki: The Moon is gradually receding from the Earth into a higher orbit, and calculations suggest that this would continue for about fifty billion years. By that time, the Earth and Moon would become caught up in what is called a \"spin–orbit resonance\" in which the Moon will circle the Earth in about 47 day... | [
"The Earth is postulated to become not-very habitable in about 250 million years due to increased solar output. "
] | [
"If you're asking if the rate increases over time, the answer is no- it decreases. The moon is moving away from us, yes, but it's slowing down. A quick calculation: 3.5 cm a year for 4.4 billion years (impact event) does not place the moon back at Earth. R2 = R1(d1",
" / d2",
" ), so R1 (4cm/yr), d1(current orb... |
[
"Why are the French words for uncle, aunt, and cousin basically the same as the German words for them instead of from Latin?"
] | [
false
] | null | [
"\"oncle\" (uncle) comes from Old French and ultimately Latin (av)unclus.",
"\"tante\" (aunt) similarly comes from Old French (ante) and Latin amita.",
"\"cousin\" also comes from Latin cōnsōbrīnus.",
"So... What was your question exactly?"
] | [
"I guess OP's question should be the other way around: why are the German words for Uncle and Aunt descended from the Latin terms instead of the Old High German kinship terms?",
"I was curious but a cursory Google search didn't provide an answer. I did find that Old High German had different words for father's br... | [
"In German you can tell that words like family (Familie) are from some romance language as German has very strict pronunciation rules and it is one of the very few words that breaks those rules"
] |
[
"How in the heck do human beings end up eating all the nutrients they need to stay alive, without using complex charts and careful diets?"
] | [
false
] | null | [
"Despite what people advertising certain diets will tell you, humans are actually quite capable of getting by on a ",
" variety of foods. Breeding populations of humans living almost entirely on meats (like Inuit), vegetarians, peasant farmers living on a diet of mostly rice or potatoes, people getting by on mac... | [
"You seriously need to provide some sources here."
] | [
"a) If you're in the US, consider that RDA's overstate requirements. If you need, say, 90mg of vitamin C, consider that what that really means is that 95% of the population (your subpopulation, really) needs 90mg of vitamin C to show no signs of deficiency. If you instead look at individual needs, you see that fo... |
[
"Why is Brazil's northeast semi-arid?"
] | [
false
] | The is a (sub-)region in the northeast of Brazil that is known to have a semi-arid climate. How is this possible, when this region is so close to the equator and not nearly at a latitude where you would expect a desert? | [
"The wiki page is mostly descriptive. Two tentative reasons I could find on the page are:",
"Because of the relatively cool temperatures in the South Atlantic Ocean, the intertropical convergence zone remains north of the region for most of the year, so that most of the year is very dry.",
"Although annual rain... | [
"I would infer that it is from the atmospheric transfer of dust and sand from the Sahara Desert from east to west. I would refer to the second link which is the paper where geophysicists monitored the atmospheric transfer with Lidar.\nThen again this is only one possibility as it is in the southern hemisphere ~6-15... | [
"The main reason for the semi-arid climate of the Sertao is orographic rainfall (rain caused by a change in the terrain altitude) which occurs, for example, in the Planalto da Borborema (or ",
"Borborema Plateau",
"). \nSince it lies between the coast and the inland Sertao, the preciptation that should occur fr... |
[
"Could geneticists create a hybrid of a human and another mammal, such as a big cat?"
] | [
false
] | For example, a human with a cat's ears and tail. Would our DNA technology allow us to create one in the foreseeable future? | [
"not to mention how much more complicated a human is than a tobacco plant...",
"anthropocentric bias is bad science.",
"Homo sapiens (human) genome = 3,000 Mb",
"Nicotiana tabacum (tobacco) genome = 4,434 Mb",
"Tobacco has more genes, more diverse biochemistry, higher chromosome ploidy, more exons, and grea... | [
"Why?"
] | [
"Thank you for your answer. I now feel guilty for smoking and will soon turn to cannibalism."
] |
[
"Does 0∞ = ∞ in the same way that 020 = 20?"
] | [
false
] | null | [
"This question was asked very recently. ",
"Here is my response",
". The expression 0*∞ is indeterminate."
] | [
"That's actually not my question. It's not so much 0 ",
" infinity, it's if you put 0 in front of infinity, like how 34 is the same thing as 034"
] | [
"No. ∞ is a symbol which is shorthand for many limiting processes. It is not a digit."
] |
[
"What are the chances of getting breast cancer if you've had a mastectomy and had a new breast grown from your own stem cells?"
] | [
false
] | Imagine you're female, and have had a mastectomy to remove a cancer in one of your breasts. If they could grow a new breast for you to replace the old one using your own stem cells, what would your risk of developing cancer be? The purpose would be to have a natural, real breast instead of a prosthetic one or an impl... | [
"This technology doesn't exist at all yet so any answer you get is going to be mildly less accurate than picking a number out of a hat."
] | [
"The answer is it depends.",
"When you're born, you have an A percent chance of developing breast cancer, where A is a function of the genome you inherited from your parents.",
"As you age, you have a B percent chance of accumulating enough mutations in your one of the cells of your breast that it becomes cance... | [
"Is this hypothetical or frickin awesome?"
] |
[
"Why do insects without wings not break their legs when they fall from a high place?"
] | [
false
] | null | [
"simple square cube law... the strength of any material (bones, shells etc )is proportional to its cross sectional area (square of length). the weight of the body ( this effects the force of fall) is proportional to its volume ( cube of lenght). in small sized bodies like insects, the force of fall is easily withst... | [
"Because they are so small. An object falling will tend to reach its terminal velocity, when air drag balances out weight. All else being equal, drag depends on cross-sectional area and speed (squared), while weight depends on volume. This means doubling the length of a creature will increase its drag at a given sp... | [
"In general yes.",
"(Excluding creatures capable of flight, which can control their terminal velocity.)"
] |
[
"Is \"Carl Jung and Isabel Briggs Myers typology\" well-supported by actual studies?"
] | [
false
] | Just found out about this, and my girlfriend and I are both coming up very accurately to the personality test we took. However, I'm familiar with studies showing how people tend to agree with general statements about themselves (hence why we're so vulnerable to horoscopes). Just wondering if any psych people can let me... | [
"Absolutely any psychological variable is a result of both nature and nurture.",
"The ",
"reliability",
" (i.e. will you get consistent results at multiple test times?) and ",
"validity",
" (i.e. is the test an actual reflection of what it claims to reflect?) of the Meyers-Briggs test are debated; some st... | [
"What I'd love to see done is perform these tests and then do a ",
"principle component analysis",
" of the data to see if there are any really separable dichotomies. "
] | [
"Do you have any studies showing this that don't come from the Myers & Briggs Foundation? My understanding of this test is that it lacks construct validity, lacks reliability with repeat testing, does not correspond with more established measures of personality like the \"Big Five\" model (beyond differentiation o... |
[
"Why did Saturn’s rings form as rings?"
] | [
false
] | I would assume that ice and dust would have various different orbits over the planet, and would therefore cover the planet in a more splotchy patter (such as clouds do on earth) as opposed to forming on a single orbital to create rings. I would also think they could just form moons. | [
"I'm addition to the other descriptions about why rings last instead of clumping up into moons, the reason rings form in the first place is the same reason galaxies, planets, moons, etc all tend to be in the same plane. They're all basically rings that clumped up into planets or moons long ago.",
"The original d... | [
"Saturns rings are made up of ice and rock particles that orbit the planet. The rings extend out from the planet roughly the distance from earth to the moon and the rings are about 3 football fields tall. Some of the particles in the rings are small and others, the size of a bus.",
"Gravity keeps all of these par... | [
"Some (not much) of the particulate does slowly fall away, but is replaced by eruptions from Saturn's frozen moons.",
"The moons also help keep the rings intact by acting as shephards, slowing down the loss, making it more feasible to maintain for long periods of time."
] |
[
"How do bacterial vaccines (like whooping cough vaccination) work? I was always told growing up only viruses could be vaccinated against."
] | [
false
] | Recently while listening to SciShow on YouTube they discussed the history of the whooping cough vaccine. This of course made me curious, growing up I'd always been told you can only vaccinate against viruses, but whooping cough was a bacterial vaccine. Do the two types work off the same principle? Can it be done for al... | [
"Originally, bacterial vaccines were made from killed bacteria. These vaccines generally have more side effects because of the presence of parts of the bacterial membrane called endotoxins that trigger fever and inflammation even in very small quantities. In addition, many times vaccinating with the whole bacteria ... | [
"So yep, they work based on the same principle. ",
"Proteins specific to the bacteria you are vaccinating against are contained within the vaccine. Your body reacts to these proteins to create protective antibodies against them.",
"If the actual bacteria is later encountered, antibodies directed against the s... | [
"Don't forget the cancer vaccines! It's really all about antigens and provoking/stimulating an immune response. It doesn't have to be prophylactic... "
] |
[
"What causes the octet rule?"
] | [
false
] | It's commonly taught that the octet rule can be used as a general rule of thumb for defining why atoms behave the way they do to fill their valence shells. But what is the actual reason for this behavior and why is an s-orbital and a p-orbital defined as a full valence shell? | [
": In electron orbital theory, we work with the assumption of a single electron atom around the element's nucleus, at a particular energy level. ",
"Given that, and given the (non-relativistic) ",
"Schoedinger Equation",
" aka Wave Function or the (relativistic) ",
"Dirac Equation",
", one can solve the e... | [
"So then with alkali metals, its less of a \"they want to give away their extra electron\" and more of a \"they have an extra electron that is relatively loosely bound to the nucleus and is often pulled away by more electronegative atoms?\""
] | [
"That has to do with other properties, namely effective nuclear charge and electron affinity. ",
"Looking at bromine, its configuration is 4s2 3d10 4p5. As you keep moving right across a period, the nucleus gains a +1 charge, but the electron is added to the same shell that doesn't get any bigger, but rather the ... |
[
"When I blow out a candle, what specifically has caused the flame to \"go out\"?"
] | [
false
] | null | [
"Four ways to put out a fire:",
"Removal of fuel",
"Removal of oxidizer",
"Removal of heat",
"Breaking the chemical chain reaction",
"The last one is probably the most interesting; Halons work by breaking the chain reaction, binding up free radicals.",
"However, for the purposes of blowing out a candle ... | [
"When you blow on a candle you displace the flame away from the wick/wax so no new heat is generated near the wax to melt it form more fuel. At the same time your breath/air cools the wick/wax by ",
" such that whatever heat is left is not enough to ignite the candle again. However, if there's smoke, there's stil... | [
"you are cooling the wick/fuel below it's ignition point. "
] |
[
"How can DNA or any other non-radioactive molecule have a half-life?"
] | [
false
] | null | [
"It's not a radioactive half-life, it's a chemical one. Over time the molecule breaks down into smaller ones."
] | [
"There is a basic definition for half-life which applies to all compounds - the time it takes for a compound to go down to half of its original concentration. Why the concentration may go down varies depending on what you are talking about. In terms of radioactive materials, they naturally go under different types ... | [
"Not necessarily. Some molecules are auto-catalytic. The main reason that DNA is more stable than RNA is the absence of the hydroxyl (-OH) group on the 2' carbon in the ribose backbone. That hydroxyl group can interact with nearby phosphate groups and degrade the ribose-phosphate backbone. The lack of the hydroxyl ... |
[
"In significant figures, why are leading zeroes not included?"
] | [
false
] | For example, 0.012 is two significant figures by what my teachers and textbooks have said, but in my head, 0.012 can't somehow be the same as 7.812, just with less significant figures. Sorry if my description of my point of view is bad. Logically in my head, the leading zeroes still define what the first part of a numb... | [
"Significant figures are not the same as decimal places. Let's say that you're measuring the height of a small bush and you find that it's 0.517 meters. You can't make a unit conversion and then say that you know that it's 20.354 inches, because that's far more precise and implies much more certainty than your orig... | [
"I'm not sure if I fully understand the question, but I'll try my best.",
"1.2 * 10",
" is this number (0.012) written in scientific notation. You wouldn't include the leading zeroes here, would you? Zeroes only count as significant digits if they are sandwiched between other non-zero digits, or if a decimal pl... | [
"The leading zeros are just placeholders for the units. For instance let's say you have:",
"0.012 m\n7.812 m",
"Now if you want to express these in different units, say mm, you get:",
"12 mm\n7,812 mm",
"Notice that the initial zeroes just \"vanish\" if we change the units, they aren't real digits. This is ... |
[
"How do animals recognize their own species if they don't know what they look like themselves?"
] | [
false
] | [deleted] | [
"It depends a lot on the animal you're asking about. Many species don't use visual cues at all to mate, depending instead on chemical cues. Basically, recognizing \"prey\" vs \"friend or mate\" would involve a combination of olfactory,visual, and audio cues recognition if which is both innate and learned."
] | [
"Absolutely! Olfactory is one of the greatest senses in the animal kingdom. Being able to detect prey or predators from their scent is a big part of survival. Being down wind from a predator and being able to smell them first could just mean that you live for another day. "
] | [
"Google \"white blood cells\" and what you read will say pretty much the same thing."
] |
[
"Where does tidal energy come from (yeah, the moon, but...)?"
] | [
false
] | [deleted] | [
"You can find ",
"past threads with a quick search",
".",
"The short answer is that the moon slowly ",
" gains orbital ",
" energy, and the Earth slowly loses rotational energy - so the energy comes from the Earth/moon system."
] | [
"You're correct. I focused on the kinetic term, and since I know the moon is moving to a higher orbit, it will have lower kinetic energy - hence the awkward wording."
] | [
"The short answer is that the moon slowly loses orbital kinetic energy",
"Not sure what you mean by \"orbital kinetic energy\". Normally we say \"orbital energy\" to mean mechanical energy, the sum of kinetic and potential.",
"And actually the Moon is increasing its orbital energy. The pull from Earth's tidal b... |
[
"If you ground up sand to be finer, would it act like silt? What about silt ground down to the size of clay?"
] | [
false
] | From what I've read, the main difference between sand/silt/clay is the particle size, as well as the shape of the particles to some degree. But I haven't found any resources that effectively explain what sand vs. silt vs. clay actually . Sand is ground up stone, which are primarily silica (SO2), right? So is silt rough... | [
"The terms \"sand, silt and clay\" are a reference to the grain size of ground up stone and is inorganic and that's really all it is. ",
"These distinctions become important when calculating porosity and permeability of fluids."
] | [
"To clarify on this:",
"The answers to the questions in the title are ",
" and ",
". But it wouldn't just act like silt/clay, it would be silt/clay."
] | [
"To go a bit farther, clay is complicated because it refers to both a size class and a class of minerals that tend to be in that size class. Sand and silt can be any mineral, but in practice quartz and (to a lesser degree) feldspars are most common. Clay minerals are very different; they're platy like mica, always ... |
[
"How do scientists define life in regards to abortion laws?"
] | [
false
] | null | [
"What do you mean by \"in regards to abortion law?\" Do you mean legally? If so, this question is better suited to some law- or policy-related sub for whatever specific country you are interested in."
] | [
"There's still a bit of mix-up in the way you are describing this: ",
"at what point during the pregnancy does a fetus become a human and no longer eligible to be aborted\"",
"What does \"become a human\" mean? human gametes, zygotes, embryos, fetuses, etc. are human from the outset by definition (in contrast t... | [
"So the unicellular gamete (sperm or ovum) is a human gamete from the outset. It is a single cell that is different from gametes of other species. When a sperm and ovum merge, they form a human zygote (still unicellular). This is also called a human embryo. This single cell divides, eventually forming a human blast... |
[
"Why is it that most of the solid planets in our solar system are arranged closer to the sun than the gas planets?"
] | [
false
] | This is for the astronomers out there, is there a particular gravitational relationship between the density of planets? It's been my understanding that planets after mars, such as Jupiter, Saturn, Neptune, and Uranus, do not have "ground" so to speak, or are just predominately gas planets. However, they have a much gre... | [
"Well, this is not really correct. The reason why the inner planets are rocky is not due to a lack of rocky material in the outer Solar System. In fact, the gas giant planets like Jupiter contain rocky cores that are much larger than any of the rocky planets like Earth, Mars, etc.",
"Instead, the reason why gas... | [
"Don't read too much into this yet.",
"Both of the most common methods we use for detecting exoplanets are very much more sensitive toward detecting closer and larger planets. And that needs to be taken into account when taking the data we have and extrapolating it into some statistical information about ",
" p... | [
"Planets of a certain size and density will be gas planets (because the have enough gravity to retain the gas)",
"There's speculation that large planets act a meteor absorber which would suggest outer gas planets has a useful function to protect life. If they do, it stands to reason that our solar would have oute... |
[
"Is there any relation between when symptoms appear/disappear, and when a person is contagious?"
] | [
false
] | [deleted] | [
"What about cold then? "
] | [
"This depends on the disease you're describing. The cold? The flu? Typhoid fever? HIV?"
] | [
"Peak shedding is usually 48h after infection if delivery is intranasal, with a rapid decline afterwards (see Heikkinen, Lancet, 2003). Some shedding occurs for days afterwards, so the host remains contagious, but nearly as much as earlier. At least, if the 'cold' in question is a rhinovirus (there's other variet... |
[
"How do antiperspirants work chemically?"
] | [
false
] | From doing my own research I have seen only generalized examples of the reactions that make antiperspirants block the eccrine gland, but was looking for a more in-depth answer on the chemical reactions which lead the aluminum salts to reduce, and what reactions occur that cause the aluminum ions to cause the sweat glan... | [
"Your answer was succinct, but maybe improve your read of the question. Antidepressants aren't all that good against underarm sweat."
] | [
"How can I better answer your question?"
] | [
"How can I better answer your question?"
] |
[
"How does Febreze that claims to eliminate odors in the air, not just mask them, actually work?"
] | [
false
] | The commercials show bubbles sucking up noxious gases. That's clearly not a real thing. How can the spray eliminate a bad odor? How does it select "bad" odors and not cancel its own fragrance? | [
"The bubble analogy is an adequate kindergarten explanation. \nFebreez contains cyclodextrin, a donut shaped molecule.",
"\nWhen applied, odorous molecules (helped along by water in the spray) get \"caught\" in the center of the dounut. The added heft of the cyclodextrin stops the molecule from binding to recepto... | [
"I like how you upgraded the bubble analogy for a donut analogy."
] | [
"I'm not familiar with what else is in febreze but they probably add in a fragrance that is not water soluble/polar so that it can't form a complex in the middle of beta cyclodextrin's ring, so you replace the odorous molecules with nice smells instead of burned bacon"
] |
[
"What the total amount of temporary packet storage in the world's routers? How much data can actually be in transit at any given time?"
] | [
false
] | null | [
"Larger routers can have 128MB to 256MB of cache on each linecard (for example, a multi 10Gbps port linecard for a Juniper M320). bdunderscore's answer is also insightful. If you go to the Cisco or Juniper website, find the section for large carrier/enterprise routers and then start checking the datasheets for th... | [
"You should really avoid using the term 'cloud' because it gets confusing since that's already the name of an established technology.",
"If all you care about is the transient information traversing the wire then it's likely quite a bit, but that's like saying you can increase the storage space of a room by throw... | [
"I'm not sure offhand how much storage are in typical core routers, but keep in mind that you also have to consider how much data can be inflight on long-distance cables. Some of the cables from the US to Japan can take as much as 50ms (one-way) to cross. If one of those cables has, say, 300 gbit/s bandwidth, that'... |
[
"How does medication actually help with clinical depression?"
] | [
false
] | [deleted] | [
"A link to a relevant thread from just a little while ago with some good answers:",
"http://www.reddit.com/r/askscience/comments/18ytm5/why_chemically_speaking_do_some_antidepressants/"
] | [
"That's kinda like asking which came first, the chicken or the egg. Are depressive thoughts symptoms or are they triggers or are they the illness themselves? I believe they are symptoms that also trigger worsening depression. Medication helps a few ways. SSRI antidepressants leave more serotonin for your neuron... | [
"Thanks!"
] |
[
"Is there a difference between haemoglobin-deficiency and erythrocytes-deficiency? Are they the same?"
] | [
false
] | I have trouble finding a precise answer for this... this is what I know so far: The cause (for both?) is lack of iron. Which results in lack of red blood cells/haemoglobin = anaemia. So if that's the case, it seems like you can use them interchangeably... but at the same time I'm thinking why use separate words then? ... | [
"Erythrocyte= greek word for red blood cell.",
"Haemoglobin= latin word for the oxygen carrying pigment molecule inside red blood cells",
"An erythrocyte contains hundreds of millions of haemoglobin molecules",
"Haemoglobin deficiency means no/low number of pigment molecules in erythrocytes ",
"Erythrocyte ... | [
"Thank you! :)"
] | [
"Iron deficiency is only one cause of anemia. So yes, there's a difference between a deficiency in red blood cells and deficiency in hemoglobin. As you might expect, if you can't make hemoglobin, you'll probably have fewer RBCs, and vice versa, but since there are many causes of anemia, it's important to distinguis... |
[
"Why do space shuttles rotate when they lift off?"
] | [
false
] | I've never seen a live launch, but from what I can tell, there seems to be a slight rotation a few seconds after liftoff that either goes on for quite some time, or stops after a few seconds. Is this just a matter of weight distribution within the shuttle? More power in one thruster? | [
"Shortly after clearing the tower, the Shuttle began a combined roll, pitch and yaw maneuver that positioned the orbiter head down, with wings level and aligned with the launch pad. The Shuttle flew upside down during the ascent phase. This orientation allowed a trim angle of attack that was favorable for aerodynam... | [
"The Shuttle flies \"upside down\" when launching, the roll is to align it on the desired orbital plane. The launch tower is not aligned for it to be oriented correctly for the orbits the Shuttle commonly uses, thus the roll maneuver is required. Initially the course is almost straight vertical, then as begins to b... | [
"http://en.wikipedia.org/wiki/Space_Shuttle_abort_modes"
] |
[
"How do cold blooded animals survive below freezing temperatures?"
] | [
false
] | I get that cold blooded animals take on the temperature of their environment and can deal with a wide range of body temperatures. From what I know, many of them decrease activity during winter when temperatures are lower. My question is specifically about temperatures below the freezing point of water. How can an organ... | [
"Hello! I have degrees in molecular genetics and human physiology, so I’m not an expert in amphibian/reptile physiology. But I’ll give your question a go!",
"The problem with most animals (mammals, for example) when it comes to freezing is the formation of ice crystals inside of our cells. They physically get ... | [
"Hi there ",
"/u/spacemonkeyzoo",
"!",
"The short answer is that there are two main ways for ectotherms to avoid freezing: 1) behavioral and 2) physiological. Behavioral examples include the animal moving to a place that is not freezing. Think about digging underground. Physiological examples are aspects of t... | [
"Much worse than that. The bottom of the oceans are all at freezing temperatures. If ice were denser, then it would all sink to the bottom, cementing over the ocean floor. There'd be a thin layer of liquid water on top of that for life to inhabit.",
"The oceans would also be much, much saltier, since the formi... |
[
"What living thing has the highest density? Or the lowest"
] | [
false
] | Including animals, plants, etc | [
"It can be difficult to do an 'absolutely most or least' assessment, but I would venture a guess that the coral ",
"Agaricia undata",
" is among the most dense organisms at about ",
"2.45 g/cc",
", that's several times more dense than hardwood. ",
"Least dense is more difficult for me. There are some diat... | [
"I would venture a guess that the coral Agaricia undata is among the most dense organisms at about 2.45 g/cc, that's several times more dense than hardwood.",
"If you read the methods section of the paper you linked for that number, they say that they dried the corals in the sun before measuring. The number, ther... | [
"I meant to imply that ",
" water between the sieve plates is considered part of the organism then it would have a density near that of water.",
"If we consider that water to be part of its environment then the density of the remaining organism would be very low. Water can move freely through the sieve plates i... |
[
"Is there a limit to the amount of energy that can be in one place at one time?"
] | [
false
] | Is there some characteristic of space-time that limits the amount of energy that it contain at any given point? Or is it just limited by the amount of energy available in the universe? | [
"Not really. Sometimes you hear the term \"mass energy\" to refer to the particular type of energy we're talking about here, just as we say \"kinetic energy\" or whatever. But that's just a bit of verbal wankery, really.",
"To be honest, mass is a big pain in the ass. It's been known since antiquity that objects ... | [
"Please write a book targeted at about the same level audience that you write to on reddit! Or if you already have under a different name, please let us know what it is.",
"Your writing makes science interesting in a way that it hasn't been since I was a little kid being told how fireworks work and trying to m... | [
"If you cram too much into one space, you get a black hole."
] |
[
"Why is it assumed that the firing of a neuron represents a binary signal?"
] | [
false
] | Wouldn't it be more efficient for neurons to pass messages encoded using some method e.g. amplitude, frequency or chemical? Is there some evidence that rules out complex signals (i.e. data beyond 1 or 0) from a neuron? Is this cognitive bias due to the strong metaphor of the "brain as a computer"? | [
"They do use amplitude and frequency and chemical signaling. Just at a higher level of complexity than one action potential.",
"Amplitude: two effects here. First, population coding (",
"http://en.wikipedia.org/wiki/Population_coding",
"); a group of neurons can encode the response to a stimulus. The other ef... | [
"Well, let me explain first how neuron works.\nNeurons are cells that transmit information via electric signals. They are composed of (approximately) three parts:",
"one sensor part, which gets information from other neurons (",
")",
"one effector part wich transmits information from the neuron to another neu... | [
"Good points, except for the first half of your first sentence. There's no way \"binary\" is the best way to describe the signals of the brain."
] |
[
"Learning about electricity. Does power increase or decrease in relation to resistance??"
] | [
false
] | So P=VI Or P= (V /R Or P= (I Trying to wrap my mind around why the power would get larger as resistance gets smaller in the first equation, but the opposite in the second . Thanks Edit - not sure how reddits math formulation works haha | [
"If you fix the ",
" V across the resistor, the power dissipated is inversely proportional to R (P = V",
"/R).",
"If you fix the ",
" I flowing through the resistor, the power dissipated is proportional to R (P = I",
"R).",
"These are physically different. If you fix the voltage applied across the resis... | [
"I remember being confused by this exact thing in physics class, so I hope I can clear it up for you. The most important thing is the equation P = V*I really is P = dV*I where dV is the \"change in voltage\". Voltage itself doesn't really mean much, what is important is the difference in voltage from one place to a... | [
"The usual case however, is that you fix the voltage drop.",
"A wall socket has a more or less fixed voltage, if you pull the voltage too low (by connecting too little resistance), it will act as a short-circuit, and safety features will cut it out. If you design something with batteries, you also don't want the ... |
[
"Is the matter that made up the sperm and the egg that formed me likely still in my body?"
] | [
false
] | null | [
"Ok, thanks! I should really stop putting so much faith in received wisdom!"
] | [
"Just a heads up, but this is actually inaccurate. ",
"http://www.abc.net.au/science/articles/2008/11/18/2422506.htm"
] | [
"A human ovum weighs 3.6 micrograms according to wiki. Assuming it's mostly water, which has an rmm of 18g/mol, there are 3.6 micrograms/18g/mol moles, or about 3* 10",
" moles. If you multiply this by avagadro's number then you get 2* 10",
" molecules.",
"The RDA of water in the USA is 3.7 litres,",
"http:... |
[
"How much g-force can the human body withstand? Once beyond that point, what are the effects on the human body?"
] | [
false
] | [deleted] | [
"Here is John Stapp decelerating at -46G, going from 614-0 mph in less than 1 second: ",
"http://www.youtube.com/watch?v=3UEYxf4fl_A"
] | [
"What the ... how is that even survivable? Isn't that almost like hitting a wall?"
] | [
"This might be worth reading",
" (PDF)",
"FAA\nAcceleration in Aviation:\nG-Force"
] |
[
"Does matter last forever?"
] | [
false
] | null | [
"Matter doesn't turn into energy or vice versa. Different forms of energy can be converted from one another, and this includes energy in the form of an object's rest mass being converted to kinetic energy of a less massive or massless object. Energy is a quantity, matter is what we call a collection of stuff.",
"... | [
"There is no evidence of proton decay."
] | [
"matter doesn't have a really firm meaning in physics. The particles that make up matter may well exist forever. Electrons will likely last forever. Protons are presently thought to last forever, but we suspect that new extensions of physics may well allow them to decay on very long time scales. ",
"And energy is... |
[
"When was it first proposed that moonlight was actually sunlight reflecting?"
] | [
false
] | [deleted] | [
"The first person to propose this that I'm aware of was Anaxagoras in about 450 BC. Anaxagoras believed that the sun, moon, and stars were all large rocky bodies that had detached from earth, and that the sun and stars were on fire, while the moon reflected the sun's light."
] | [
"Yet I work with people who think the sun and moon are just providers of light. We're in gods aquarium folks "
] | [
"Welp there goes my weekend... i just stumbled in this place last week and think I've read like 400 posts already. Now... there is more??!!"
] |
[
"Some questions about radioactive dating."
] | [
false
] | I believe in an old earth, but I have several friends who are adamant young earth creationists. Whenever we discuss this difference one thing they always bring up is the fact that diamonds usually have trace amounts of C14 in them. My answer has always been that carbon dating is only used for once-living matter. Why is... | [
"In the air, there is always new C14 being created due to cosmic rays causing the creation of fast moving neutrons which hit N14, destabilizing the atom and causing the, now, N15 to release a proton turning the atom into C14. This happens at a more-or-less constant rate so that any C14 depleted from the atmosphere ... | [
"For questions about the evolution-creation debate, I always refer people to ",
"Talk Origins",
" because it provides a pretty thorough examination for all of the evidence for and against evolution. ",
"Here's",
" the section (or one of them) about carbon-14."
] | [
"C-14 is produced in the upper atmosphere where nitrogen gets hit by cosmic rays. As the C-14 mixes with the rest of the atmosphere, it spreads roughly evenly across the surface of the globe, creating a standard ratio of C-12/C-14. Living creatures and active carbon processes pick up the C-14 that is created. On... |
[
"How was cancer treated in the 1930s or 1940s did the treatments work or did you just die?"
] | [
false
] | null | [
"Firstly, a primary reason why cancer is the second leading cause of death (after heart disease) is that people are living longer, allowing it to overtake other like stroke, pneumonia, tuberculosis, and diarrhea. Fewer people had to worry about dying of cancer in the early 20th century because something else was m... | [
"Before the development of chemotherapy in the 40s cancer was treated the same way it had been for hundreds of years - surgical resection of the tumor. ",
"In many cases, especially early on, it was thought that the harm caused by (relatively primitive) surgery wouldn’t be outweighed by the benefit of removing pa... | [
"Fanny Burney, the writer, had a mastectomy in 1812 and described the procedure, which was performed without anesthesia. It sounds terrible, but was successful—she lived another 29 years. ",
"https://www.theguardian.com/books/2018/jun/22/the-evil-was-profound-fanny-burney-letter-describes-mastectomy-in-1812"
] |
[
"Are more stars currently dying or being born? basically, is the number of stars increasing, decreasing, or staying the same?"
] | [
false
] | [deleted] | [
"So first a bit of background on why this is maybe a more interesting and harder to answer question than a first glance may show. Many of the stars that are born are very low mass and very long lived, while the ones that die off in the time that the universe has existed (roughly those a bit less massive than the Su... | [
"Total layman here, so maybe i misunderstood something you said but,\nsince new stars are being formed, where is this material coming from? Also, in terms of potential to host life, is the milky way become more or less hostile?"
] | [
"The material is gas and dust spread around the plane if the galaxy. Bunches of it can slowly collapse because of their self-gravity, maybe kick started by turbulence bring a crtitical mass together. If you go to a place with a dark sky and look at the Milky Way, you'll be able to see lots of dark streaks in it - t... |
[
"Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"If I understand your question properly, you are wondering how it can fly if there's nothing to push against? ",
"You're not the first person to think this way- the NYTs actually published an editorial mocking Goddard for saying rockets would work in a vacuum",
" only to correct it later. ",
"My favorite way ... | [
"So, I don't think I follow what you're saying. Yes, mass and energy are linked through Einstein's equation- but that has nothing to do with how much thrust we get. ",
"And yes, practically, an ion engine never makes enough power to get a rocket to leave Earth, but there is nothing in principle not allowing it."
... | [
"Planets are just definitions of particular objects. \nAs of the current definition, yes, you wouldn't need much more than a few Jupiter's worth of mass in order for hydrogen fusion to start, and then you have Brwon Dwarfs.",
"Some people don't think Brown Dwarfs are stars, but they are their own thing, so yes, t... |
[
"What Sequences of DNA are Common Through all Life on Earth?"
] | [
false
] | null | [
"ATG ?"
] | [
"Most of the DNA in eukaryotes is non coding junk DNA (99%). Much of this is ",
" between species, and more so if they share common descent.",
"edit: my use of conserved here is misleading. All I meant was that DNA will be similar between similar species."
] | [
"ATT is a popular one..."
] |
[
"Does ice sublimate in freezers?"
] | [
false
] | I was looking at the and I don't understand how ice can sublimate in a freezer. At 1 atmosphere and say, -10 to -15C, it looks like the ice would have to melt before reaching the gas phase. Or the pressure would have to drastically drop. Does ice really sublimate in a freezer and if so, how? | [
"It doesn't sublimate, ",
"Huh? Of course ice sublimates in freezers, for exactly the reasons you describe: a nonzero equilibrium vapor pressure that's higher than the actual surrounding gaseous water pressure."
] | [
"\"It doesn't sublimate\" as in: if one was to increase the temperature of the system then a stable liquid phase is reached which is in equilibrium with the solid phase. This was what the OP was asking about.",
"It seems to me, and their responses confirm, that the question is whether the ice can go directly from... | [
"From the solid and its surroundings. At any temperature, you have a range of molecular energies, so there'll always be some molecules in the condensed state with enough energy to break their bonds and launch into the gas phase above."
] |
[
"What determines how \"hard\" it rains vs. the duration of the downpour?"
] | [
false
] | [deleted] | [
"That's really fascinating.",
"How do the shape and type of clouds form? Is it also tied to the terrain and water source? Does the shape and type of cloud play off of the intensity of the storm?"
] | [
"That's really fascinating.",
"How do the shape and type of clouds form? Is it also tied to the terrain and water source? Does the shape and type of cloud play off of the intensity of the storm?"
] | [
"That makes complete sense. I live in Florida and all we ever really get are huge deluges, but I have spent a lot of time in the Pacific NW and it seems like all they ever get is days of drizzling without end."
] |
[
"What is the best way to increase voltage?"
] | [
false
] | The direct power supply provides 220 Volts, but a machine needs 440 Volts to run. My father says it's not possible to increase voltage in a practical way but I think adding resistors can double the voltage. Is this dangerous? Will it overheat? Is there a better way to do this? Neither of us understand electrical engine... | [
"I think adding resistors can double the voltage...",
"You're probably thinking of Ohm's law, but for this to happen, current must remain constant. If the power supply gives 220 V, add resistors will not increase the voltage. It'll in fact ",
" the available voltage for the load. Think of the water analogy - po... | [
"Thank you! Will the machine work just fine if the current is lowered? If so, I will look for someone who can make a custom transformer."
] | [
"That depends entirely on how much current your appliance draws. You should consult someone who's more knowledgeable (and can examine the systems)."
] |
[
"How did they isolate N-Acetylglucosamine and N-Acetylmuramic Acid from Peptidoglycan?"
] | [
false
] | We're studying the bacterial cell wall, and the professor told us that it's made of the aforementioned monosaccharides. I asked him how they were able to determine that, and he said that he wasn't sure. It's just what the book says, so he takes the books word on it. I would love it if someone gave me the exact scientif... | [
"While the ",
" method may have been lost in the history (or just didn't become common knowledge), a cursory search in the literature reveals ",
"one method",
" of determining the constituents of peptidoglycans - lysozyme treatment.",
"The search was literally as easy as this",
"."
] | [
"Holy smokes! Thanks!"
] | [
"GAG degradation is well studied pathway due to its relevance in mucopolysaccharidosis. Each enzyme along the degradation pathway cleaves off a monosaccharide. "
] |
[
"How far away could SETI detect Earth?"
] | [
false
] | Tried to keep the title short, but basically if you duplicated Earth, how far out could you move it before SETI would not be able to detect our current EM emissions? | [
"Here's some links to similar discussions on reddit: ",
"https://www.reddit.com/r/space/comments/2kjboc/the_extent_of_human_radio_signals_into_the_milky/",
"https://www.reddit.com/r/askscience/comments/nli3f/if_a_copy_of_earth_existed_a_distance_similar_to/",
"https://www.reddit.com/r/askscience/comments/q15l... | [
"Seeing aside travel time what kind of bandwidth could that maintain? "
] | [
"Seeing aside travel time what kind of bandwidth could that maintain? "
] |
[
"Just how dangerous is radiation in space?"
] | [
false
] | Space news websites often post new articles about the danger of space radiation to Mars astronauts, and often describe the radiation levels as completely prohibitive. NASA does that, too, but often in very vague terms, like "we need to know more" or "more research is needed". On the other hand, people like Robert Zubri... | [
"I'll start by distinguishing radiation sources since this is frequently confused here in AskScience:",
"What we normally consider prohibitive is GCR. Their energies are of 300 MeV at the peak of the spectrum, but there are particles with more than a GeV of energy. They will traverse whatever you put in their way... | [
"They do. But not without causing damage.",
"GCRs are ions, mostly protons and alpha particles, with a few occasional heavier nuclei. When they traverse matter they start interacting electromagnetically with electrons in it. The incoming particle slows down as it delivers part of its kinetic energy; as a conseque... | [
"To add on, I think that one additional uncertainty is in the \"linear no threshold\" model of radiation harm. We have decent knowledge of how bad short term radiation exposure is. If you get exposed to 1 Sievert of ionizing radiation on a short timescale (say over the course of a day), then it increases your life... |
[
"Am I more likely to spread or contract an illness if I have a beard?"
] | [
false
] | I'm thinking this might be the case because of all the extra surface area near my nose and mouth that can attract or collect pathogens. | [
"Wow that was rude"
] | [
"Wow that was rude"
] | [
"Abstract",
"An investigation was conducted to evaluate the hypothesis that a bearded man subjects his family and friends to risk of infection if his beard is contaminated by infectious microorganisms while he is working in a microbiological laboratory. Bearded and unbearded men were tested with Serratia marcesce... |
[
"There's a spot on my dog's back where, if I pat it twice, she shivers. What's the deal?"
] | [
false
] | [deleted] | [
"The part of her back that you are patting has a large sheet of connective tissue under the skin called the thoracolumbar fascia, which anchors the latissimus dorsi to the spine in the lower back. The latissimus dorsi does quite a bit of work in our canine friends and puts the thoracolumbar fascia through a good de... | [
"Makes perfect sense. That also explains the scratch reaction, the similar reaction that cats give when being scratched in the same spot, and why scratching my back for an inordinate amount of time when I wake up in the morning feels so damn good."
] | [
"Oh. My. God. I never realized that liking to have my back scratched may be functionally the same as a dog. I've always joked about putting up a piece of tree bark in the house and just scratching away bear-style. I never thought it might be because a bear and I feel the same way about it."
] |
[
"Why does it take multiple years to develop smaller transistors for CPUs and GPUs? Why can't a company just immediately start making 5 nm transistors?"
] | [
false
] | null | [
"Ex Intel process engineer here. Because it wouldn't work. Making chips that don't have killer defects takes an insanely finely-tuned process. When you shrink the transistor size (and everything else on the chip), pretty much everything stops working, and you've got to start finding and fixing problems as fast as y... | [
"Nanotechnologist here!",
"Because when a transistor is very small, it has a number of side effects like quantum effects and short-channel effects. Also, transistors work by doping semiconductors, if the semiconductor is very small there are very few doping atoms. Also, a small imperfection results in a big effec... | [
"You'd verify each particular process step (etching/deposition) with an electron microscope - you'd get to a prototype only ",
" you've build and verified process and machines that can reliably make arbitrary patterns at that resolution. "
] |
[
"How much more Powerful would a Graphene Superconductor Battery be than a same-sized Lithium ion Battery ?"
] | [
false
] | [deleted] | [
"Don't confuse power with storage ability. Perhaps the battery could supply much higher wattage, yet still hold far less energy.",
"100 watts for 1 minute is much higher power than 5 watts for 60 minutes, yet the latter is more total energy."
] | [
"I have no idea how much more capacity they would have, but 20x sounds a lot to me. With the same battery size, you could get a month of smartphone use or 10.000km range on electric car.",
"If the price would also be compatible (it probably won't) this huge amount of storage would also solve the problem with rene... | [
"20 times more energy storage would be huge and would revolutionize many industries, particularly electric vehicles. That's not the same thing as 20 times more power though, which just means it can discharge faster."
] |
[
"Couldn't you circumvent the uncertainty principle and pinpoint the momentum and position of an electron by firing 2 photons at it at the exact same time; one high energy and one low energy?"
] | [
false
] | [deleted] | [
"No.",
"The first thing to understand is that the uncertainty principle isn't an issue with our measurement techniques.",
"Particles are not just particles, they are probability density functions which describe where the particle is likely to be found. If a probability density function narrows in momentum space... | [
"No. I'm not sure how to explain why that won't work, because I'm not sure why you think it ",
" work."
] | [
"Time and energy",
" also share an uncertainty relationship. "
] |
[
"Why can an adult’s GI tract expel C. botulinum spores while an infant can’t?"
] | [
false
] | what is it about infants that make them susceptible to botulism from eating honey that adults are safe from? I’ve asked my professor and she only said it’s cause the adult’s GI can expel the spores while an infant’s doesn’t but I’m still wondering how so. | [
"Your professor is wrong; it is nothing to do with expelling the spores. ",
"The botulinum bacteria is a poor competitor. In an environment where there are already lots of other established bacteria, it struggles to form toxin-producing colonies; babies have less developed gut flora, not just because they haven't... | [
"In addition to this comment, pH also plays a very important factor in botulism sporulating in the stomach. The pH of an infants stomach acid is not low enough to prevent botulism from germinating (come out of spore-form). I believe the magic number is 4.6 if memory serves from classes in college. Under that acidit... | [
"So the exact reason behind why isn’t 100% understood, in fact it took ages to figure out which foods were more likely linked to infant botulism (like honey) and is just a very easy thing to eliminate from infants diets to lower the risk. Infants aren’t born with a developed GI flora of good bacteria which help def... |
[
"A company called Neurosky have released a consumer EEG device with a single electrode. Will it actually measure enough brain activity to be useful?"
] | [
false
] | I'm interested in it as a meditation aid and for concentration training, as well as just for personal interest. Is it actually likely to be useful for this purpose, and what limitations should I be aware of? At the beginning of the video in the background you can see the sort of output it gives. | [
"Hey I have used one of these and I am part of a group engineering and open hardware EEG. I can tell you it shows very generalized data which is fun for trivial tasks and biofeedback, but it isnt as versatile as something like the Emotiv headset. If you have any technical questions I can help. I am more the hardwar... | [
"Lol the way it works connecting it like that with the resistor will drive that instrumentation amp crazy. When it is hooked up to a person it does really well at cancelling noise. I gutted a neurosky and it has decent filter and digital signal processing takes care of the rest. Its filter method is differential th... | [
"We aren't measuring potential difference per se in an electro encephalagraph. So the difference isn't measured from electrode to electrode. Instead we compare the electrode to ground to find the frequency at which the neurons are firing. The second electrode here is only providing a non neurological body signal to... |
[
"What exactly is the theory status of black holes?"
] | [
false
] | I was reading in my august-issue , and I skimed past an article about black holes. I didn't read the whole article, but from the text extractos I did read I picked up that it was about a group trying to photograph the shadow of the black hole (belived to be) at the center of our galaxy. I got the impression that this ... | [
"There's no such thing as \"theory status.\" There are things in the sky that have properties consistent with black holes."
] | [
"So in short, they exist, we've seen them, and I misunderstood. That works. Thank you!"
] | [
"The thing is - you can look at something that has properties consistent with black holes. And we have. But how do you know it's not something else that just happens to have the properties of a black hole? The key property of a black hole is an event horizon. And event horizons, by their very nature, are very diffi... |
[
"Why does a nylon scrubber scratch aluminum?"
] | [
false
] | I have some old aluminum heat syncs I plan to re-purpose as trivets. Cleaning with cheapo green plastic scouring pad leaves fine scratches. I actually like the brushed look but am wondering how a softer material can scratch a harder one. | [
"That looks like a Scotch-brite pad. Scotch-brite pads contain either silicon-carbide or aluminum oxide. That's the main abrasive, the nylon is just there to hold the fine particles of them. I'm pretty sure that green is the course aluminum-oxide pad, making it very abrasive.",
"I believe the white pads are the n... | [
"I guess it depends upon the product, but ",
"this",
" MSDS says the pad is ",
"nepheline syenite",
" in polyester; not quite as abrasive as silicon carbide."
] | [
"Nepheline syenite is 20% Aluminum oxide. Al2O3 has a hardness of ~9.0, aluminum has a hardness of ~2. I'm sure that a number of other compounds in Nepheline syenite also have a hardness >2. (SiO2, which is 50% of Nepheline syenite has a hardness of ~7.)"
] |
[
"What prevents a car/engine from surpassing its top-speed? What's happening when it is reaching that point?"
] | [
false
] | null | [
"That's what limits the engine from spinning too fast.",
"On the off-chance that the OP was referring to the whole car, it's friction. The faster you go, the more you increase friction with air. This will create an opposing force, that increases with speed.",
"At some speed, the opposing force is too great for ... | [
"That's what limits the engine from spinning too fast.",
"On the off-chance that the OP was referring to the whole car, it's friction. The faster you go, the more you increase friction with air. This will create an opposing force, that increases with speed.",
"At some speed, the opposing force is too great for ... | [
"I assume you mean the maximum RPM of an engine? The maximum RPM of a car engine, usually called the redline, is based on a few physical factors.",
"First, the rotating mass in the engine. High speed rotating things have lots of energy, causing high stresses. Spinning all those components too fast may damage s... |
[
"mass-energy equivalence or E=mc2...why the speed of light squared?"
] | [
false
] | null | [
"Because we didn't know space mixed with time when we invented the metre and the second. It's sort of like if you decided to measure left-right in metres and forward-back in feet and then started doing maths you'd get the constant metre/feet (≈ 3) coming up a lot.",
"In particle physics c is usually set to 1 (by ... | [
"To understand, you have to see how the units are derived from each other.",
"According to Newton's laws of motion, force is mass multiplied by acceleration. F = m.a",
"In the SI system of units:",
"Using those units in the above equation results in:",
"F = 1 kg * 1 m/s^2\n = 1 kg·m/s^2\n",
"This is wher... | [
"This is a frequently asked question. ",
"Here's one part of the answer: \"c\" is not really just the speed of light. \"c\" is the fastest speed anything can achieve in the universe. It's the universal speed limit. Light moves really fast. At the speed limit (in a vacuum). It isn't the only thing that moves that ... |
[
"Where does the proton's mass come from?"
] | [
false
] | [deleted] | [
"You are correct that the quark masses are fairly insignifficant The majority of the mass of the nucleons comes from the kinetic energy of the quarks and the field energy of the gluons. We can even make a pretty good approximation of the nucleon masses based on their sizes of approximately 1 femtometers, here's how... | [
"But where does the approximation that the potential from the strong force would scale as X",
" come from?",
"It's just the volume, there is no X",
" dependence. The energy density is approximated as just some constant, thus the total massenergy grows with volume. Specifically, ",
"M(from gluons) = VB ",
... | [
"Neither; it's the binding energy between the quarks and gluons that make it up. Mass isn't really its own \"thing\"; it's just a form of energy: namely, the energy that something has when it's at rest with no external forces acting on it. The vast majority of that energy in the proton is binding energy between its... |
[
"Second Hand Slow on First Second"
] | [
false
] | When glancing at the second hand on an analog clock, why does the first observed second seem to take longer then the following ones? (please tell me this doesn't happen to just me) | [
"this isn't the karma-whore ville of askreddit. you don't need to post \"hurr i dunno lol\""
] | [
"There's also a good video about the illusion ",
"here",
"."
] | [
"There's also a good video about the illusion ",
"here",
"."
] |
[
"Are ants capable of flatulence?"
] | [
false
] | null | [
"Do insects fart? Yes!",
"Do insects have an anus? Yes!",
"Do insects have intestines? Yes!",
"Do insects fart out their butts? Uhh, maybe, maybe not.",
"Insects don't have lungs to pump air around, instead their body is full of tiny holes called ",
". Gases diffuses in and out passively. Some of those... | [
"Great, \"is it a fart if it doesn't come out of your anus\" is not the existential crisis I was expecting to face today. Thank you."
] | [
"An entire ant hill emitting methane? Easy to study. Done, done and done.",
"You even get different emissions from the same species, but in a different location. Different gut bacteria.",
"What we don't know, or have evidence for, is where that gas comes from the ant body. It seems more likely to be burping... |
[
"Can chickens have identical twins?"
] | [
false
] | Would they have to come from one egg? I found some references to a chicken with two heads and that sort of thing, but didn't see much about chickens having otherwise normal healthy twin chicks. | [
"Twins are known from a number of bird species, and viable twins originating from a single yolk are known for both chickens and pigeons. However, the only record (as of 1999) of genetically identical twins stems from ",
"emus",
", and even then the twins had some size differences after birth."
] | [
"Just to clarify. The birds don't originate from the yolk. The yolk provides the unhatched chick with nutrients. "
] | [
"So what's the deal with double yolk eggs?"
] |
[
"Is there any evidence that experience can affect genes?"
] | [
false
] | [deleted] | [
"It's called epigenetics and it's really cool. It doesn't modify the genetic sequence, but it modifies which genes are methylated and controls how genes are expressed.",
"There's evidence, for instance that people who were molested as children have different gene expression in their brains. ",
"link"
] | [
"Check out research by Moshe Szyf; there're a lot of popular articles about his work as well."
] | [
"In a recent article using ",
"mice",
" showed that high fat diets de-methylated a gene involved in metabolism in normally skinny and fat mice. While there was no significant gene expression changes, the work suggests you diet may be more important than you think."
] |
[
"How much of Sigmund Freud is still relevant in the world of neuro/psychology?"
] | [
false
] | Or to a more specific question, is there any good scientific/neurological basis to concept? I am trying to look for information on ego as a concept, and perhaps in the process conquer my own. So any books, texts recommendations are appreciated. | [
"Just an undergrad here. His therapy is horrible, and his ideas were unscientific. That doesn't mean that they're necessarily invalid.",
"is there any good scientific/neurological basis to Id, ego, and super-ego concept?",
"Do you need any? You want a cookie (Id), you plot how to steal one from the cookie ja... | [
"You will still find therapists that use 'modern psychoanalytic' approaches.",
"It is rather difficult to find testable hypotheses formulated on his theories. ",
"However, the concept of the subconscious is still very important in neuroscience. Much of what your brain is computing is not available to you cons... | [
"A lot of people like to bash him, but some of the concepts he wrote about have influenced many others to formulate ideas and theories that are actually useful. Also, I think ego, id, and superego can be useful metaphors sometimes, and that's all he really intended them to be."
] |
[
"Why is there so little natural iridium on Earth?"
] | [
false
] | null | [
"The overall abundance or Iridium (and other Platinum-Group Elements) is comparable to that of gold. However, very few geological environments provide geochemical conditions which allow the preferential mobilisation and concentration of Ir. Pretty much the only place that happens is at the base of Mg-rich ultramafi... | [
"It is and it isn't. The mafic material in the maria is relatively undiffrentiated, so the background in incompatible elements is somewhat elevated - those are referred to as KREEPs (basalts enriched in Potassium, Rare Earth Elements and Phosphorus). But having an elevated background level is a far cry from an expl... | [
"I once read that the moon is full of PGE's especially Iridium ... and that it's used in hydrogen/water based catalytic energy producers e.g astronaut's powerpacks"
] |
[
"Can a virus have a really long incubation time, say months, be highly infectious during incubation and have extremely high mortality rate?"
] | [
false
] | As in a virus that gives little to no symptoms for months or even years and suddenly becomes highly lethal? Would we, with modern medicine, even be able to detect such a virus before it is way to late? | [
"HIV is such a virus. After initial infection People can be asymptomatic for years. - 10-15 years in fact. During this “latency period” Tests would still reveal HIV+ status, but many who are infected do not get tested and continue to spread the virus. Which is why they encourage people who are risk of HIV to get te... | [
"Rabies is highly infectious. ",
"What you mean to say is that it isn't highly contagious (perhaps 'isnt highly transmissible' is more appropriate)."
] | [
"Prion disease I don’t see mentioned. Examples in humans are Jakob-Creutzfeldt disease or Mad Cow disease.",
"It is currently affecting the deer population in North America (Chronic Wasting Disease).",
"It’s a seriously bad way to go, and utterly incurable/untreatable. 100% mortality rate but slowly."
] |
[
"Can L'Hôpital's Rule be applied again if lim x->c f'(c)/g'(c) fits the original criteria? And what's the inuition behind the rule to begin with?"
] | [
false
] | L'Hôpital's rule, to the best of my knowledge states that, if lim x->c (f(x),g(x)) is (0,0), (+inf, +inf), or (-inf,-inf), then lim x->c f(c)/g(c) = lim x->c f'(c)/g'(c) My question is: suppose lim x->c (f'(x),g'(x)) = (0,0), (+inf,+inf), (-inf, -inf). Can one "apply L'Hôpital's Rule" again ... i.e. is it the case that... | [
"Yes you can apply the rule again! The rule only cares about whether or not the function fits the criteria, not where the function came from! And in your problem sets, you'll probably see limits that you can only solve by applying it twice.",
"As for the intuition behind it? Hmmmm.... Basically, if you have an in... | [
"The intuition behind l'hopital rules comes from the ",
" of a function around some point ",
"A theorem due to that Taylor guy states that, around ",
":\nf(x) ~= sum for k = 0 to N: (x-a)",
" f",
"(a) / k!\nwhere f",
" is the k-th derivative of f\nthis approximation is good enough in the sense that all ... | [
"For the first question, yes.",
"For the second question, here's a very simple intuitive justification of the rule: Assume that f(x) and g(x) both approach 0 as x goes towards c. Moreover, assume that f'(c) = a and g'(c) = a. This means that if we zoom in to a sufficiently small neighborhood around c, f(x) ~= a(x... |
[
"Can moons have moons?"
] | [
false
] | null | [
"There's nothing explicitly preventing that if the system is set up properly, but it would be very unlikely to form naturally. The first moon has to be far enough from the planet that the planet's gravity won't destabilize the second moon's orbit, but not so far that the planet no longer influences it substantially... | [
"Isn't this question more vaguely, \"Can a satellite orbit a satellite?\" In which case Sun -> Earth -> Moon "
] | [
"Another interesting thing to note is that it seems some moons can have rings around them. Saturn's moon Rhea may have a tenuous ring system, for example. So it's possible for moons to have some form of debris in their orbit, even if it isn't necessarily an entire moon per se."
] |
[
"Is an acorn considered living?"
] | [
false
] | null | [
"Like other nuts, an acorn is a seed, an embryonic tree-to-be wrapped in a hard shell. But only the lower end of an acorn's innards is occupied by a rudimentary root and stem; the rest is nutritive tissue loaded with protein, carbohydrates and fat. Its purpose is to sustain a sprouting seedling until the infant gro... | [
"And to answer the question as posed, yes an acorn like all nuts are living tissue."
] | [
"Seeds are often in a form of stasis where respiration is either halted or extremely slow. Germination triggers the seed to turn respiration back on to the \"normal\" level and triggers the initial seedling growth.",
"As long as you do nothing to kill the seed (poison it, cook it, freeze it) it will function corr... |
[
"Is there a model that predicts what the continents will look like in several thousand years?"
] | [
false
] | If we can measure their movement, and have hypothetical models for how the earth looked in the past (Pangea), than can we create a model that predicts how the earth will look in a few thousand years? Even 10,000 or 100,000 years? | [
"As mentioned by ",
"/u/Slave_to_Logic",
", your time frames are VERY off. Plate motion is measured in mm/year and extremely fast rates are a few cm/year (",
"here",
" is a map of current plate motion rates and directions as measured by GPS for context). So at rates of between 1-5 cm/year (5 is definitely o... | [
"At such proximal time horizons as 1000 or even 100 000 years, the effects of continental drift are negligeable. The general outline and position of continents remains the same. Most of the effects you'll have will come from sea level change, erosion and migration of climatic zones. ",
"We ",
" have projections... | [
"The real implication of these projections being that we will all have to wait ~50 million years until we can stop suffering through geologists working in Tibet bragging about working in the \"largest active continent-continent collision in the world\". Mediterranean Mountains for the win."
] |
[
"Why do Virologist use Vero(Monkey Kidney) cells to culture respiratory viruses and respiratory tract cells?"
] | [
false
] | Edit: | [
"Think of vero cells as the factory to make virus in vivo. It doesn't need to be the perfect target for infection, it needs to make more virus.",
"Vero cells are an established immortal cell lines. You can grow them (nearly) indefinitely and keep a stock going all the time. They grow dense and have good yields of... | [
"+1 for this - yes, we use vero for everything from Zika to CoV2 (COVID) because they grow well, the lack of type one interferon responses in these cells mean many viruses replicate better, and they also tend to die in response to viral infection which means we can use it plaque assays (“clear” areas on a dish due ... | [
"Many virologists also mention interferon defect as one of the main reason"
] |
[
"Is there an unbiased website that lists the scientific community's majority consensus on common subjects?"
] | [
false
] | Questions like "do vaccines cause autism?", "do cell phones cause cancer", and "are pesticides safe?" that laypeople care about but don't want to dig through journals. | [
"Careful with that statement; it could be interpreted to mean that all information should be taken with the same degree of incredulity, which is not true. Some things are simply wrong while others may only be wrong in the sense that the given information tends to lean towards a certain bias which may not necessari... | [
"For medical topics, you could always try \"",
"The Cochrane Library",
"\". They publish meta-analyses of research on specific topics. It's still fairly technical but they provide \"plain English\" summaries.",
"For example, a search for \"vaccines autism\" yielded ",
"this",
"Researchers from the Cochran... | [
"Wikipedia isn't the best by any measure; it's horribly biased - towards populism and sensationalism. By which I mean that subjects that have lots of fans, and which have lots of public interest (which does ",
" correlate to mainstream ",
" interest) gets lots of attention and correspondingly large articles.",
... |
[
"how come gravity doesn't pull everything together to make one giant ball of stuff?"
] | [
false
] | null | [
"Another reason is that gravity by itself is a ",
". The combined kinetic and potential energy of an object moving in a gravitational field stays the same. But for two objects to merge energy must be dissipated. If the objects are already on a collision course then the collision will dissipate the energy, but spa... | [
"Because the universe is expanding too quickly. To a first approximation, you might say that distant objects are receding away from each other faster than the respective objects' escape velocity, so they don't form gravitationally-bound systems.",
"Things like galaxies and galaxy groups, and smaller, those syste... | [
"so if the universe stopped expanding gravity would be able to?"
] |
[
"Are you able to be allergic to EpiPen? And if so what alternative would there be for someone that has an allergic reaction?"
] | [
false
] | null | [
"The active ingredient in an EpiPen is Epinephrine, I believe that because this is already present in our bodies in small amounts you can’t be allergic to it and there has never been a documents case of an epinephrine allergy."
] | [
"I don't know that all epipens are exactly the same, but the \"non active ingredients\" would be the concern. These ingredients, known as excipients, can cause allergic reactions in people. It is well known that some allergy medications contain excipients that cause histamine reactions in some people, it stands to ... | [
"Thank you very much"
] |
[
"Why do the melting points of linear alkanes form a zig-zag curve?"
] | [
false
] | I'm referring to where alkanes from methane, ethane, n-propane, n-butane, et cetera are plotted against their melting temperature. There is a general trend upward, but also a periodicity of two, where even and odd-numbered alkanes agree with each other, alternating between higher and lower than expected based on the tr... | [
"Yep- the longer the hydrocarbon, the less significant the terminal steric awkwardness as a proportion of the total interaction between molecules."
] | [
"Melting point, boiling point, and a variety of other physical properties are the result of intermolecular forces, often seen as attractive forces, between molecules. For non-polar, simple chain alkanes such as these, the only attractive force we need to worry about are dispersion/London/ van de Waal's forces (diff... | [
"So why does the graph even out at higher carbon #s? Is it just a matter of hydrophobic interaction forces eventually outweighing the steric awkwardness (IANACh) of the molecules' shapes? I can't access the pdf at home :/"
] |
[
"Why is the Earths core made of Iron"
] | [
false
] | As we all know the earths core is made of iron because it is one of the denser elements but, there are more dense elements on earth so why hasn't gravity pulled them to the center to form a new more dense core? | [
"There are probably other elements in Earth's core besides Iron. There is also Nickel in there and other elements. The issue with the denser ones is that there simply aren't enough found on Earth to be a significant player in what Earth is made of. ",
"https://secure.wikimedia.org/wikipedia/en/wiki/Abundance_of_e... | [
"A lot of Hydrogen would have escaped early on when Earth was hot (right after accretion). It is also not gravitationally bound. That being said its also very light and my listing was by mass."
] | [
"Two causes.",
"1). Iron is one of the ",
"most abundant elements",
" and by far the most common metal. This is because its particularly stable; it has the ",
"maximum binding energy per nucleon",
". Lighter elements can always fuse together (fusion) to get more tightly bound together releasing energy,... |
[
"Where does the energy for electron degeneracy pressure come from?"
] | [
false
] | When a star is in the Main Cycle, the internal gas pressure is provided by fusion power. When the star collapses, electron or neutron degeneracy pressure stop the implosion to form a white dwarf or neutron star, respectively. And it does so forever, almost. Gravity is always there. So where does the degeneracy power co... | [
"It's an effective force: there is an energy associated with the star as it is, there is an alternative state it can enter in which an additional atom is added to the core plasma, contracting it slightly (releasing gravitational potential energy), but requiring the electron to be put into a very high energy state, ... | [
"Thanks for the explanation. However, I still don't get where the force behind Pauli's exclusion principle comes from, i.e. which of the four fundamental forces that is."
] | [
"It doesn't come from a force, it comes from a requirement of quantum mechanics. Because of quantum field theory (and that's honestly as well as I know the reason, I've not been exposed to that much yet), particles with integer spin (bosons) have symmetric wave functions, and particles with half-integer spin (fermi... |
[
"Why do small animals (rabbits, mice, etc) have a faster heartbeat compared to larger animals (elephants, whales, etc)?"
] | [
false
] | To my knowledge, I thought smaller animals have a smaller volume therefore less blood needed to be pumped. Does it have to do with the volume-surface area ratio? What is the factor is that is influencing this? edit: spelling | [
"Heart rate varies due to the relative difference in surface area to volume as volume increases. The smaller the animal, the greater surface area it has relative to volume, so it loses heat exponentially faster. This necessitates a more active metabolism, faster heart rate is a part of that. "
] | [
"I study math, not biology, but there are some very interesting ",
" that describe how various attributes of animals scale with their size. ",
"For mammals, homeostasis is a big energy requirement, and the volume-surface area ratio implies that smaller animals lose their heat much more rapidly than larger ones.... | [
"the heart rate vary with size as It turns out that within the major \ngroups of vertebrates, mass-specific metabolic rate increases with \ndecreasing body size. This means that for a given amount of body mass, a small animal has a higher metabolic rate than a large animal. Since heart rate is a major factor of m... |
[
"How many sounds are needed to represent all human languages? Would a single human be able to generate all sounds?"
] | [
false
] | null | [
"There is an alphabet that does exactly this. ",
"http://en.wikipedia.org/wiki/International_Phonetic_Alphabet",
"The IPA provides the academic community world-wide with a notational standard for the phonetic representation of all languages. There are 107 letters, 52 diacritics, and four prosodic marks in the I... | [
"\"Accents\" are just different phonemes (symbols on the chart) being used instead of another. For example, in the word \"father\", Received Pronunciation, or British English would use the sound /ɑ/ for the \"a\", while in the General Australian accent, we use /ɐ/.",
"Once you've been taught how to perceive all o... | [
"\"Accents\" are just different phonemes (symbols on the chart) being used instead of another. For example, in the word \"father\", Received Pronunciation, or British English would use the sound /ɑ/ for the \"a\", while in the General Australian accent, we use /ɐ/.",
"Once you've been taught how to perceive all o... |
[
"How is/are light and/or electrical impulses converted into information like pictures or sound on a computer?"
] | [
false
] | How are we able to take information in the form of light from fiber-optic cables and convert that into data, like an image or sound? I assume it has something to do with binary code but I could be wrong. | [
"Let's forget about light/electricity for the moment, and just focus on a way for me to send a \"picture\" to you using only numbers. ",
"In general, this is a complicated topic, but let's start with something simple, a black and white bitmap. Suppose you and I agree on a way to express a picture as a series of n... | [
"The concept of binary is based of one and zero. True and false. Basically a 1 is a signal, whereas a 0 is the lack of a signal. This is the basis of all computing. Each bit in a computer can either be set to let a signal through, or block it. If it is blocked it is read as a 0, if there is a signal it is read as a... | [
"In practice it is a little more complicated than this. In order to make transmission more reliable, signal encoding is used. Many coding schemes are based around the changing of the signal rather than the value of the signal. ",
"For example, a scheme might be something like this: Every clock cycle, if the signa... |
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