title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Hypothetical time! Assuming an indestructible balloon with no leakage, would it stop rising eventually?"
] | [
false
] | Let us assume we have a balloon, not dissimilar from a weather balloon. This balloon is unbreakable, and does not leak any gases contained within. Let us also assume we have filled this balloon with enough hydrogen (instead of helium, for simplicity's sake) to rise at sea level. Would this balloon escape gravity comple... | [
"The balloon/capsule material is heavier than the atmosphere at sea level, notwithstanding its \"lighter-than-air\" contents.. As the atmosphere thins with altitude, it reaches a point of equilibrium where the balloon can rise no higher."
] | [
"Pretty much.",
"The air in the football is much lighter/less dense than the water, and the weight/density of the football itself is greater than the water. The gas in the football rises/floats, but once at the surface, the gas is the same weight/density as the atmosphere and the football is heavier than the atmo... | [
"Would this be comparable to letting go of a ball filled with air (such as a football) underwater? It goes up until it reaches a point of equilibrium (in other words, it floats, but the atmosphere presumably doesn't have quite such a defined surface as water does)."
] |
[
"Do multiple evolutions of traits imply an 'ideal biological form'?"
] | [
false
] | Perhaps this is a silly question, but it's something I've always been curious about. Does the fact that certain traits have independently evolved (such as the supposed ) across the spectrum of creatures imply that evolution may be 'seeking' an ideal form, so to speak? That certain biological mechanisms are ideally suit... | [
"The problem with your question is that evolution is blind. There is no perfect organism that is being selected for. In fact, often times deleterious traits can be selected for or become fixed in populations due to stochastic processes. ",
"In cases where traits have evolved several times independently, such as i... | [
"No. There is no 'ideal biological form'.",
"Check out \"convergent evolution\"."
] | [
"Perhaps in a completely sterile, unchanging environment with only a single organism you could get to a condition that was essentially static, but evolution would still occur due to aforementioned stochastic forces. As long as there is DNA as we know it there is evolution.",
"There's always going to be Red Queen,... |
[
"Long after humanity disappears from the planet, what will be the last remaining sign we were ever on Earth?"
] | [
false
] | null | [
"I'd say our imprint of mineral resource use.",
"My argument will be based on the age distributiuon of metals stocked in ore deposits. When one plots known ore deposits according to age of formation, they can be treated statistically just like any other age-sensitive population.",
"However, after our passing, ... | [
"I would imagine the voyager probe. ",
"It directly identifies us as living on the third planet from the sun. So that covers that part of the question. ",
"And as for being the longest lasting, it's in interstellar space, which is markedly vast and empty (unlikely to see a destruction event), going at a speed w... | [
"I would think the unusually high concentrations of radioactive materials in small geographic areas (former power plants or waste locations)."
] |
[
"Why are people suddenly having an issue with gluten?"
] | [
false
] | I don't understand how "gluten free" has suddenly become a need when it comes to the diets of human beings. There is evidence that human beings have been eating wheat for well over 10,000 years. How is it that something which has been a major part of the human diet is suddenly becoming a problem for human ingestion? Wo... | [
"As far as we know, there are three different disorders of which a gluten-free diet can avoid symptoms.",
"Celiac disease (CD)",
"Wheat allergy",
"Gluten sensitivity (GS)",
" has been recognized for a long time. It's rare (",
"between 1 in 105 and 1 in 1,750",
" people in US) and can cause serious healt... | [
"Link to top-level post answering the question.",
"Reported symptoms include muscular disturbances, neurological disorders, attention deficit, hyperactivity disorder, migraine, headache, sleep disturbance, lethargy, tiredness, and cerebellar ataxia, bone or joint pain, and also psychiatric disorders such as autis... | [
"Link to top-level post answering the question.",
"Reported symptoms include muscular disturbances, neurological disorders, attention deficit, hyperactivity disorder, migraine, headache, sleep disturbance, lethargy, tiredness, and cerebellar ataxia, bone or joint pain, and also psychiatric disorders such as autis... |
[
"Does laughter have different accents?"
] | [
false
] | null | [
"\"Although our laughter may be as distinctive as our speech, laughter is not infinitely variable,\" Robert Provine, research professor and professor emeritus of psychology and neuroscience University of Maryland, Baltimore County, tells Mashable in an email. \"If we all laughed differently, we could not identify a... | [
"The result doesn't sound very much like a laugh — at least not a convincing one.",
"I just tested this, extending the 'blasts' to about a full second each.",
"\"haaaa... haaaa... haaaa...\". ",
"Totally convincing."
] | [
"have more in common with the barking of a dog than speech",
"But dogs barking has an accent",
", so if that can have an accent, then surely laughter can have an accent as well. So while what you posted is interresting, I don't feel like it answered OPs question fully."
] |
[
"A question of tastebuds."
] | [
false
] | Two questions actually: Can someone explain why children have such a strong desire to eat candy and anything sugary and sweet while adults very rarely have these same cravings? I know that it's something to do with development and as you age you develop tastes for different things (Ie. I taught myself to love olives wh... | [
"OK, there are 5 tastes: sweet, sour, salty, bitter and umami. In your mother's breast milk you get sweet and umami so you are naturally conditioned from birth to like these two tastes. Bitter and sour we developed over time (anthropologically speaking) to warn us away from poisonous (bitter) and rotten (sour) food... | [
"Didn't like olives and don't like peppers? You might be a ",
"supertaster",
" - someone with higher tastebud density and correspondingly higher taste sensitivity, particularly to bitter flavors.",
"I can't think of any sort of evolutionary reason for this when other people like peppers and I may love foods ... | [
"This was great. Thanks so much. And you're right, my grandpa douses his food in so much salt I sometimes think he should just eat it by the spoonful and forget about the food altogether. "
] |
[
"What makes an organism male or female? (Besides humans)"
] | [
false
] | I get that we can differentiate between different sexes of animals, but how do we classify one as male, and one as female? I assume not by which one bears the offspring because male seahorses get pregnant, not females. | [
"Here's one way:",
"In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete—called an ovum (or egg)—and a male produces the smaller tadpole-like type—called a sperm.",
"http://e... | [
"Male seahorses actually don't get pregnant, the female seahorse just deposits the fertilized eggs in a specialized pouch on the male. ",
"http://en.wikipedia.org/wiki/Seahorse#Reproduction"
] | [
"Do we have examples of species where both gametes have the same size? Where any two gametes can merge into a viable offspring (in which case there wouldn't be sexes per se but still sexual reproduction, I guess)?"
] |
[
"What limits radiation in the center of a star?"
] | [
false
] | [deleted] | [
"Wikipedia says up to 150 times as dense as water, which would make it about 7 times as dense as the densest materials you'll find on earth. Note that despite this high density, the core of a star is a gas, due to the high temperature."
] | [
"At the center of a star, matter is very dense, and the photons produced have to travel through this very dense ball of matter to escape. Along the way, it interacts with the matter very often. As the photon finally escapes the dense core and reaches the outer layers, the time between interactions decreases."
] | [
"Not all stars are created equal. In red dwarfs, the entire star is convective. In a star such as our sun, the core is radiative, and the outer layer is convective. (if your book said the core of a star similar to our sun is convective, your book is wrong) In a much more massive star, the core is convective, and th... |
[
"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! ... | [
"They are becoming more common as we go through the Sun's 11 year cycle in which sunspot numbers go up and down, along with where they appear on the Sun. The Sun reverses its magnetic north and south poles every 11 years. As we approach \"solar maximum\" the number of sunspots and active regions and flares appears ... | [
"Hi,",
"I've been seeing a lot of videos of the sun and loads of \"solar flair-y\" things swooshing above the surface. ",
"Can these be dangerous for us ? Are they becoming more common ?"
] | [
"There is a coherent theory, part of the standard model of physics, that explains the weak nuclear force and electromagnetism as emerging from a unified force through symmetry breaking. Before symmetry breaking the Higgs had a lower but unstable energy, and has settled to the value we measure now. Before symmetry b... |
[
"What kind of acid does carbon dioxide turn into when absorbed by oceans?"
] | [
false
] | Edit: I just realized that the title is wrong, since carbon dioxide doesn't "turn into" an acid... Well, you get the idea. | [
"It turns into carbonic acid, H2CO3. "
] | [
"Not putting excess CO2 in the atmosphere in the first place?"
] | [
"If you happen to have a large source of energy handy, such as a nuclear reactor, you can actually ",
"pull the CO",
" out of seawater, along with H",
", and react them with each other to produce hydrocarbon fuel",
". The Navy wants the technology so that its nuclear aircraft carriers can produce their own... |
[
"If i want to know how much energy would be released by an antimatter/matter reaction, do I just plug the mass of the matter and antimatter into E =mc^2?"
] | [
false
] | null | [
"Yes, plus the initial kinetic energy of the particles if they are colliding quickly (in their center-of-mass frame). 86% of the speed of light doubles the total of energy."
] | [
"Does the temperature of the particles affect the reaction, and is it included in kinetic energy?"
] | [
"Doesn't really make sense to talk about temperature with only two things"
] |
[
"Is there any reason why all the gas giants in our solar system formed in the outer solar system? Why didn't any gas giants form in the inner solar system?"
] | [
false
] | null | [
"What's important here is a concept known as the \"snow line\".",
"Water can only exist in two states out in space - as a gas, or as ice. Since the pressure is essentially zero in space, water's phase will only depends on temperature. In our solar system, this threshold is located somewhere around 5 AU (where 1 A... | [
"which should also mean that Saturn through Neptune have rocky cores?",
"Right, all the giant planets - Jupiter through Neptune - are expected to have rocky, ",
" cores. It sounds weird to talk about ice at 20,000 degrees, but the core of Jupiter is under such incredible pressure that you can get exotic forms o... | [
"No one really expected it but gas giants close to their neighbour star seem to be fairly common.",
"I don't think there is a definite answer or clear consensus as to why this should be the case",
"There is a clear consensus on this: Giant planets are still formed farther out in any solar system, but are then s... |
[
"Could a small island sink if an object heavy enough was placed on it?"
] | [
false
] | null | [
"He (and you) are downvoted because you are wrong. For almost every definition of \"sink\", an island which is pushed below the surface of the water due to a heavy load would be \"sunk\". Floating is totally unnecessary, save for the small fact that ",
" things which sink are things that were floating.",
"If yo... | [
"Sure, it happens all the time with ice sheets or some oceanic volcanoes. But we are talking ",
" heavy objects here, and once that weight is removed they will slowly rise back up (over the course of ~100,000 years). They also take a very long time to \"sink\" in the first place."
] | [
"Potentially useful reference ",
"http://en.wikipedia.org/wiki/Isostasy",
"\nI am reluctant to answer your question fully as it is not my area of expertise however the above link may be of interest."
] |
[
"Why can some animals, like turtles, develop in to different sexes after conception based on environmental conditions, while in humans it's fixed in genetics?"
] | [
false
] | What is different in a turtle's DNA, and why don't humans have the same ability? Or do they? | [
"Still waiting for a more detailed answer but:\nIn general we have genes that relate to a certain sex. But that genes still need to be expressed to actually define a sex. For turtles the environment and especially the temperature determine how strong which sex genes are expressed. ",
"In humans that's not possibl... | [
"They do not, the gene ",
"KDM6B",
" turns on/off at a specific temperature during development which then guides the turtle to be either male or female. Genetically the two sexes are the same, and identical twins could be different sexes. In humans only genetic males have the SRY gene located on the Y chromosom... | [
"To preemt an argument, you are right ",
"...",
"In humans only genetic males have the SRY gene located on the Y chromosome.",
"There is a rare condition where the SRY gene got moved to the X chromosome and can cause a viable XX male. I think there are a couple of other weird edge cases too, like other male e... |
[
"If the inside of a black hole doesn't exist where is the energy?"
] | [
false
] | ...or what is the energy? Is it simply accepted as existing because we can see the effects of it? Sorry if this is covered in the thread which caused me to make this ( ) but I couldn't find a direct answer to this. Edit: the question obviously assumes that the inside of it doesn't exist though I understand there was so... | [
"You don't observe it. Not directly. You can ",
" it in a wide variety of ways.",
"As for how it's defined, that's context-dependent. We can say it's the Hamiltonian. We can say that kinetic energy is a quantity that depends on velocity and potential energy is a quantity that depends on position, and the differ... | [
"You can think of it as being painted on the event horizon. It behaves as if that's not entirely untrue."
] | [
"No, no they don't. No one takes those theories seriously and they go against what we know about black holes."
] |
[
"What are the implications of the NASA EM drive paper published with peer review?"
] | [
false
] | null | [
"It doesn't really have any implications. The status of EM drive \"research\" are the same as they ever were. This paper managed to get through peer review in some engineering journal, but that doesn't mean that their methods are valid and it certainly doesn't mean that the drive works.",
"The error analysis in t... | [
"Ahh. I think a lot of people are going to hear 'NASA' and think this has a lot more weight that it actually may. "
] | [
"I think a lot of people are going to hear 'NASA' and think this has a lot more weight that it actually may.",
"Yes, exactly. They hear \"NASA\" and \"peer review\" and see the sensationalist headlines, and get carried away with it. ",
"For example, the headline of the big thread on ",
"/r/space",
" boldly ... |
[
"When I shake a container of liquid, such as a jug of milk, it seems to get more thoroughly shaken if there is some amount of air in the container. Does the presence of air actually contribute to more effective mixing?"
] | [
false
] | null | [
"It's actually not the air but empty space in the container that allows the liquid to gain more momentum that is translated into more turbulent flow when it crashes to the end of the container. Basically you can achieve as efficient mixing with just a little bit of air or other empty space, but it requires some spe... | [
"What do you mean by empty space? Wouldn't any empty space be filled up by whatever gases are in the container (e.g. air)?"
] | [
"It doesn't matter, unless the liquid reacts with the gas. He's talking about a high mass liquid passing though a low mass gas. It's the moving around that's important.",
"Anyway with a full container you'd probably want to spin instead of shake. The turbulence at the corners of the vessel will contribute to the ... |
[
"The reason we can't wear contacts for too long is because the cornea needs access to atmospheric oxygen. But where does the cornea get oxygen from at night when our eyes are closed?"
] | [
false
] | null | [
"Your skin is permeable. "
] | [
"Ah, I see. Thank you."
] | [
"So are some types of contacts, like 30-day contacts that can be worn literally 24 hours a day with no eye damage."
] |
[
"Does getting infected by a virus/bacteria depend on the amount of pathogens?"
] | [
false
] | For example: long exposure to short amounts of pathogens (like airborne ones) or short exposure to huge amounts of pathogens (like HIV) what determines a pathogen's spreadability? | [
"To add to Tremor_Sense's answer, it depends on the ability of the host's immune system to defend against the invaders. If the host is exposed to just a few invading cells it can fight them off successfully. If the invader is numerically stronger it will overwhelm the host's immune system. "
] | [
"Yes. ",
"The medical term is 'infectious dose.' It's counted by how many cells or individuals in a pathogen leads to a full blown infection. ",
"So, exposure to just a few e. Coli won't likely lead to an infection, but exposure to thousands likely will. ",
"The infectious dose is different from strain to str... | [
"Ahhh thank you so much! "
] |
[
"How many dimensions are there and can they be described or what do they look like and how do they work?"
] | [
false
] | [deleted] | [
"As far as we know, there are three spatial dimensions plus time. You can ",
"look for experimental signatures of extra dimensions",
" but thus far all searches have come up null."
] | [
"Very interesting, thanks!"
] | [
"Image a 3rd dimensional cube passing through a 2nd dimensional plane. To something on the 2nd dimensional plane, it would look like something just appears then disappears. If a 4th dimensional object passed through our 3rd dimensional space, then it would look the same. Something appears out of thin air and then j... |
[
"How does an aquifer effect the rock and material it sits in over geologic time? Could you look a cross section and pick out where water used to be in ancient times?"
] | [
false
] | Edit: Yes. not effect. | [
"Like most questions, the easiest answer is \"It depends.\" I'm not an expert in hydrogeology, but I think it is safe to say that thinking of an aquifer as a static body of water that is not moving would be incorrect. Even a lake is constantly experiencing inflows and outflows/evaporation. The same is true for aqui... | [
"but I think it is safe to say that thinking of an aquifer as a static body of water that is not moving would be incorrect. ",
"Neat, I did not know that. ",
"Thanks for the elaboration. The connection between mineral veins and water transport is really interesting, would you know and good resources to learn ... | [
"That's about half of the field of economic geology. There are many kinds of ore deposits formed by water interactions. Aside from an introductory textbook or Wikipedia, not sure where to start. You're asking about an absolutely enormous topic."
] |
[
"Can I make any solid into a liquid by adding sufficient heat?"
] | [
false
] | I want to know if I can take ANY sort of substance that is in a solid form and turn it into a liquid with enough heat. I do not want to burn the substance. Some examples of the substances I am interested in are Collagen, PMMA (Poly(methyl methacrylate)), PA66 (Poly Amide 66). For anyone curious, these are some polymers... | [
"Not necessarily.",
"\nSome substances at normal atmospheric pressure will skip the liquid phase and go straight to gas.",
"\nAnd example of this would be Carbon Dioxide. Solid Carbon Dioxide is dry ice and it doesn't become a liquid when you heat it up to room temperature."
] | [
"Sublimation is the term for that.",
" It also shows that water can skip it's liquid phase given different environmental conditions (primarily pressure)."
] | [
"I suppose it is, but once you reach that level, the intermolecular bonds would no longer satisfy the requirements for \"wood\", so no, technically you could not have liquid wood. Instead, it would some sort of liquid hydrocarbon."
] |
[
"It is true that snakes, such as pythons, will grow bigger to prepare to eat their owners?"
] | [
false
] | null | [
"This has urban legend written all over it."
] | [
"This has urban legend written all over it."
] | [
"In all honesty that sounds extremely made up. There's no way a snake would ever be able to do that in the wild, so there's no way it would become a natural behavior. Sounds way too urban-legendy to me."
] |
[
"What does it actually mean for our understanding of physics and the universe that the Higgs Boson appears to have a mass of 125 GeV? Is supersymmetry ruled out? Is the multiverse theory ruled out? Is the standard model still valid?"
] | [
false
] | Just finished watching the "Particle Fever" documentary and found myself wondering what this discovery has led science to. How are things different now? What did we learn? Go easy on me, I'm not in the field of science! Thanks. | [
"Is supersymmetry ruled out?",
"No.",
"Is the multiverse theory ruled out?",
"No.",
"Is the standard model still valid?",
"Finding the Higgs boson at ",
" mass is a piece of evidence in favor of the Standard Model, so yes, the Standard Model is now more than ever \"a really good model.\" That said, we a... | [
"Thanks for the detailed reply. As I understand it, if the multiverse theory was correct, we could be at the end of physics because some particles just don't exist in our universe. Is this correct?"
] | [
"You are assuming that in a non-multiverse theory everything will have an answer. This is most likely impossible. Take the Standard Model, for example. It's a very successful model, but it doesn't provide an answer to a large number of questions, first and foremost \"why the Standard Model?\" And further, why the s... |
[
"Why does a water stream bend when an electrically charged object is brought near?"
] | [
false
] | There are some explanations that I've found, but they seem to conflict - most common being that water is a polar molecule so the molecules orientate themselves so that they are attracted to the charged object, but this video suggests that it's not so much the polarity of water but the dissolved ions flowing. So is it r... | [
"the attribution to dissolved ions is incorrect.",
"The effect results from a charge separation in the water droplet as it forms, induced by the charge on the nearby deflection device.",
"What charges are they referring to if not dissolved ions?"
] | [
"the attribution to dissolved ions is incorrect.",
"The effect results from a charge separation in the water droplet as it forms, induced by the charge on the nearby deflection device.",
"What charges are they referring to if not dissolved ions?"
] | [
"It's all three; the contribution between each of them varies.",
"The polar nature of water would be the weakest (since it's an electric dipole), whereas the ions are literally charge carriers (i.e. Na",
" and Cl",
"Derek's point is more that the reason why the water deflects isn't because it's polar (which h... |
[
"Why using binary numbers is so important for computers? How would a computer with other number bases function differently?"
] | [
false
] | [deleted] | [
"Computers use binary primarily because it's so easy to build the fundamental components (i.e. the transistor) that have either definite on or definite off states. Computers know whether something is on or off in a circuit based on the voltage and there is no ambiguity as to whether something is a 1 or a 0. ",
"T... | [
"They don't have to use binary. It's just easier to build them in this way.",
"Where it makes sense acually they do use other bases. For example a modem uses a set of sounds to represent a pattern of bits, so it is in fact using a different base because it is faster to do so."
] | [
"Computers are the simplest machines that we know how to build that do the things that computers do. If they were any more complicated than they had to be, they'd cost more.",
"Binary is the simplest numerical base for doing the things a computer needs to do. It's very easy to make a circuit that can differenti... |
[
"What is the condition/defect that causes nails/fingers like these in the bottom right picture?"
] | [
false
] | This cancer came up on my Facebook feed, but I am genuinely curious as to what causes the last one. I tried googling small fingernails/big fingers etc etc in every which way and I really couldn't find anything that resembled that picture. Genuinely curious as I do like to read up about rare genetic defects, conditions ... | [
"That is actually something else called Hippocratic nails (watch-glass nails, drumsticks) and yes, it can be caused by certain lung and heart problems, but in that picture the nails look hypoplastic - hyponychia - perhaps an expression of skeletal, limb or ectodermal developmental abnormalities or a mutation in the... | [
"That is actually something else called Hippocratic nails (watch-glass nails, drumsticks) and yes, it can be caused by certain lung and heart problems, but in that picture the nails look hypoplastic - hyponychia - perhaps an expression of skeletal, limb or ectodermal developmental abnormalities or a mutation in the... | [
"Looks like Anonychia/Micronychia.",
"It is associated with a number of ",
"ectodermal dysplasias",
".",
"Here's a ",
"review",
" if you can get access to it."
] |
[
"How do electrons distribute themselves in a cross section of a wire, when they move through it?"
] | [
false
] | In addition, would it be possible to measure differences in electron density (or probabilities of electron distribution) through a cross section of a wire with sufficiently sensitive equipment? | [
"This is a good answer. I can shed a bit more light on DC- electrons inside a metal are modeled as a ",
"fermi gas",
" and are essentially free to move. In fact that's one of the defining properties of metals, that electrons inside them can move virtually freely aside from resistance. That means that a DC cu... | [
"Depends a little bit on whether it is AC or DC. In AC signals it is predominantly on the edge of the wire. I feel a bit embarrassed but I'm not even sure about the answer to the question in regard of DC. I think it is quite uniform. Measuring the distribution will be quite hard. The best way I could imagine is to ... | [
"It might be worthwhile to note that electrons don't actually move that far or that fast in an electrical distribution system. It is the electrical potential that moves at the speed of light. Think of a long tube filled with balls. If you push another ball into one end, a ball falls out the far end \"instantly\", b... |
[
"Is there any reason to not grow plants in 24hr light?"
] | [
false
] | null | [
"Certain plants use the day/night schedule kind of like a clock, which would affect their flowering. Also, most plants can over produce under intense sunlight and use the night to process and remove the sugars from the leaves. A C4 plant like corn may be able to handle it with their more efficient vascular system."... | [
"There are a few-",
"Flowering/fruiting is triggered when the light cycle is 12 hours or less.",
"24 hour cycles can stress plants excessively when switching to the flowering stage vs a more natural 18 hour veg cycle.",
"If you are growing indoors, a 24 hour light cycle also puts excessive strain on the light... | [
"Interesting, so would lettuce be sweeter if harvested in the evening? "
] |
[
"What does p=np problem mean, and why is it so hard to solve?"
] | [
false
] | Wikipedia assumes I have prior knowledge in "computer resource management". | [
" and ",
" are classes of decision problems. That is, problems for which the answer is yes or no.",
"A problem is in ",
" if it is easy to solve.",
"A problem is in ",
" if it is easy to verify whether a proposed solution is correct.",
"Of course, ",
" must be a subclass of ",
". If it is easy to so... | [
"He's being imprecise with the words \"difficult to solve.\" He did explain what he means, though:",
"The particular notions of easy and hard is that the runtime of an algorithm solving the problem should not scale too poorly with the size of the input.",
"The problem of P=NP is not a problem that can be solved... | [
"The problem of deciding whether a mathematical statement is true or not isn't decidable — there's no algorithm that can determine the truth value of arbitrary mathematical statements. This is closely related to the ",
"halting problem",
", ",
"Tarski's undefinability theorem",
", and ",
"Gödel's incomple... |
[
"What is the limitation that causes radios such as those found in cell phones to be limited to specific frequencies?"
] | [
false
] | For example, the specs of phones will list them as being compatible with, say, 850, 900, 1900 MHz. I would have thought that this limitation is mainly a function of the antenna, but you can easily make antennas of variable length (for example, old telescoping antennas, which don't seem impossible to reproduce on a smal... | [
"The FCC has a whole lot to say about what frequencies are kosher for cell phones or other electronics to use. The choices are largely, but not entirely, arbitrary for what those frequencies are. "
] | [
"That may be part of it, but it seems like there must be a technological or scientific limitation that plays a part in this.",
"Otherwise, I don't see why in the case of cell phones unlocked global GSM phones are universally compatible only with the AT&T 3G frequencies, and leave out the T-Mobile 3G frequencies."... | [
"That limitation isn't technology, but cost. It is cheaper to produce one that only uses x frequency."
] |
[
"What is happening chemically when a chip or bread gets stale?"
] | [
false
] | null | [
"The starch is crystallising, which is what relates the hardness, and when you say chip I'm assuming you're American, in which case would be absorbing moisture from the air, the air inside chip packets is actually nitrogen which keeps them crisp. Also putting bread in the refrigerator will make it go drake quicker... | [
"Assuming drake is a technical term, does this temperature dependence extend into the sub zero region? I usually put bread into the freezer and have not yet noticed any staleness after defrosting."
] | [
"Sorry, the \"drake\" was meant to be stale, my screen ia damaged and makes typing a nightmare at the moment, I don't know the full reasoning behind it, just the basics, I think it's that refrigeration dries it out whereas freezing it the moisture is trapped inside as ice, something along those lines. Although depe... |
[
"How do you give testing animals human diseases to test drugs?"
] | [
false
] | I just saw an article on about the discovery of a drug that decreases the size of brain tumors. So my specific question is...how exactly do you give mice brain tumors? Or any other type diseases to test drugs? | [
"There are lines of mice bred to have diseases. A search of the ",
"Cancer Models Database",
" for \"mouse brain\" cancer brought back 424 results, for example ",
"these mice",
" develop ",
"medulloblastomas",
" at very high rates.",
"If you look on the ",
"Jackson Laboratory website",
", you can ... | [
"From my summer undergraduate research experience (keep in mind this is in South Korea), they would inject allergens that would induce a certain disease. For instance, we would compile a solution to induce rheumatoid arthritis to mice and inject it nasally while the mice are in an anesthetic state. I'd assume that'... | [
"There are different ways to do different diseases. The first thing to keep in mind with these is that you are ",
" giving a mouse a brain tumor; you are ",
" a brain tumor in a mouse. ",
"A few examples from my past work experience are:",
"1) Allergic airway disease to model asthma - you give a mouse as se... |
[
"Is the hydrostatic force on a dam proportional to its height?"
] | [
false
] | [deleted] | [
"Pressure in a fluid is give by ",
", where ",
" is fluid density, ",
" is acceleration due to gravity (9.8 m/s",
" ), and ",
" is the depth from the surface. For a rectangular dam, the total force would be 1/2",
" where ",
" is the width and ",
" is the height. So depending on what you mean by forc... | [
"True, but total force doesn't matter that much here. I should have phrased the answer in terms of total force per unit length of the dam but didn't want to get that involved. Assuming the dam is anchored in its foundation (which it would pretty much have to be to hold back water) the that retaining force will also... | [
"Yes, it is proportional to height. Or rather, the force on part of the dam is proportional to that part's depth below the water's surface. The very top of a tall dam doesn't need to be extremely strong, just as the dam for a shallow reservoir doesn't need to be extremely strong."
] |
[
"is it possible to substitute the hydrogen (or sidechain) on the alpha carbon of an amino acid in a polypeptide chain with another polypeptide chain?"
] | [
false
] | what i mean is like having a primary amino acid structure like this: those specific residues are just examples, i realize there might be some steric issues. on that note: also, why aren't there any naturally occurring amino acids with two sidechains? edit: i know about disulfide bonds and my biochem knowledge is prett... | [
"Covalent linkages between peptides can occur via ",
"disulfide bonds",
"As for your other questions, there actually ARE amino acids with two sidechains, they just aren't biological. What we think of as amino acids are actually ",
" amino acids because the amine group is on the alpha carbon. Technically anyth... | [
"thanks for the reply, but i am fully aware of everything you said :). i have actually been working with a lot of funky amino acid derivatives (well, actually glycine derivatives but same thing, really), and these questions popped into my mind.",
"i should have said \"why aren't there naturally occurring 2-sidech... | [
"This is pretty much how ",
"ubiquitin",
" works. The C-terminus of the ubiquitin molecule is attached to the -NH2 of the lysine side chain of the target. You get what is effectively a polypeptide chain 'branching off' the side of another. ",
"Of course, this sort of system isn't DNA->RNA->ribosome-codable s... |
[
"Ive met raw Pyrite, How does it even..?"
] | [
false
] | Hello all, Ive been a lurker in reddit for some time, really enjoying it, anyways: I was visiting Natural history Museum in London the other day, in crystals and minerals section ive stumbled upon Dont get me wrong, Im a photographer, who always like to hear more about forms...before seeing this, I always thought that ... | [
"Sure, it's part of the ",
"cubic crystal system",
". Many things have a habit like this including the pyrite you saw, galena, and my personal favorite fluorite, which looks like a ",
"Borg cube when broken",
"."
] | [
"i too thought the cube was the hardest to believe was naturally formed.",
"Which is funny, since we use a naturally cubic material every day at the dinner table:",
"http://www.flickr.com/photos/nmnh/2604572402/lightbox/"
] | [
"all representations of fractals are approximate."
] |
[
"Can you give me awesome evidence of evolution?"
] | [
false
] | So I've been given an assignment for my intro to biology class. I haven't taken science since high school, and im a senior in college and an art history major-so most of this is review/new knowledge. This class is focused on evolution and plant life. While I know of evolution and its theory, I was wondering if you in /... | [
"Richard Lenski watched some populations of E. coli for like 30000 generations, and eventually they developed ",
" that allowed them to metabolize citrate.",
"Apes have 48 chromosomes while humans have 46. If a common ancestor had 48, then it's expected that two of them would have merged to allow us to have two... | [
"The asymmetry in the eyes/skulls of ",
"flatfishes",
" is a great example. ",
"Here",
" is Dawkins talking about it and contrasting it against rays. Another good example, also courtesy of Richard Dawkins, is the ",
"laryngeal nerve",
" of a giraffe."
] | [
"The coolest example I know is the case of human ",
"endogenous retroviruses",
" (HERV). A brief summary:",
"As you might know, retroviruses are viruses that are capable of incorporating their own genetic material into the DNA of a host cell. (The most well-known of these are the viruses that cause AIDS and h... |
[
"How did HIV/AIDS come into existence?"
] | [
false
] | I'm probably just uninformed but as far as I'm aware HIV/AIDS is spread through transfer of bodily fluids (through sex or sharing of intravenous drugs etc.). If this is the case then how did someone first come to be infected by it? | [
"It developed in primates in Africa as SIV, or Simian Immunodeficiency Virus. It was most likely transferred to humans by the consumption of bush meat (a catch-all term for most meat from wild animals in Africa), specifically from primates infected with the virus."
] | [
"Check out the RadioLab podcast \"Patient Zero\" for an interesting history of the disease. "
] | [
"And interestingly siv has jumped into humans at least twice. HIV-1 and HIV-2 arose from two separate jumps into humans. "
] |
[
"How do we know the age of the earth and not just the age of the materials that made up the earth?"
] | [
false
] | After reading a book and watching that episode of cosmos involving Clair Patterson, I began wondering this. I don't doubt the results, but I am curious. | [
"This is wrong - being molten won't stop radioactive decay.",
"What solidification does do is trap the products. Zircon crystals occasionally incorporate uranium when they crystallize, but never lead. Uranium decays to lead. Measure the ratio of uranium to lead in a zircon crystal and you know when it stopped bei... | [
"This is wrong - being molten won't stop radioactive decay.",
"What solidification does do is trap the products. Zircon crystals occasionally incorporate uranium when they crystallize, but never lead. Uranium decays to lead. Measure the ratio of uranium to lead in a zircon crystal and you know when it stopped bei... | [
"Nuclear decay is not related to temperature like that. Spontaneous nuclear decay is at most weakly related to ambient temperature.",
"Radioactive decay will continue to occur in either solid or molten rock. The energy scale of chemical process like melting is orders of magnitude smaller than nuclear processes.... |
[
"Is there a significant impact of owning a pet on depression? Have there been studies conducted on this topic?"
] | [
false
] | I've seen anecdotes online about pet cats and dogs helping lift individuals out of a depressive rut, but have there been any studies on this effect on a larger scale? | [
"On my phone so this answer won’t be super thorough, but at a glance it seems psychological wellbeing benefits from relationships with pets mimic those benefits we get from ",
"human relationships",
". ",
"Benefits of pet ownership on the mental health of the elderly, physically ill, and hospitalized has been... | [
"Thank you for the analysis! I wonder what groups (e.g. elderly, mentally/physically ill, etc.) are shown to benefit the most from pets in general."
] | [
"This study",
" suggests that among healthy adults women and single people seem to benefit the most from dog ownership specifically.",
"Something I should also say is that many of these studies, since they can't really GIVE people pets for the sake of research, compare people who already have pets and those who... |
[
"How do gamma rays make bad whiskey smoother?"
] | [
false
] | I asked the same question on another subreddit, but I believe you can answer it in more depth, also I love physics (am currently studying biochemistry), so if you have any related facts, I'd love to hear them. I have read some articles on the internet that states if you irradiate bad whiskey with gamma rays, it will be... | [
"I doubt either you or ",
"/u/RobusEtCeleritas",
" is old enough to remember, but back in the 1960's, GE issued a recall on 90,000 TV's with a manufacturing defect (primarily a misaligned shield around a power supply vacuum tube) that allowed an excessive amount of soft X-Rays out of the box. ",
"According t... | [
"The purpose of food irradiation is usually to sterilize it. But it seems like they're saying that exposing certain kinds of whiskey and wine to ionizing radiation causes chemical changes in them that makes them taste better. I can't confirm or refute that, and in principle taste is subjective.",
"You'd need abou... | [
"Can you link to the articles?"
] |
[
"Does surface tension exist on the underside of the surface of a liquid?"
] | [
false
] | [deleted] | [
"No; surface tension exists because of attractive intermolecular forces among the water/liquid molecules. Once you're inside the liquid, there is no flat layer of molecules for the forces to make a wall of sorts. ",
"This image should help explain",
"."
] | [
"The underside of the liquid-gas interface does have the same surface tension as the upside though."
] | [
"Not in a way that it requires force to exit the liquid like it requires force to enter the liquid."
] |
[
"What happens between the surface of my ski or snowboard and the snow that makes me glide down the hill?"
] | [
false
] | null | [
"The coefficient of friction between the board and the snow is very low meaning that very little energy is lost to heat and sound as it glides over the snow. As far as the mechanisms of achieving that low coefficient my guess you be a partially hydrophobic coating that has a mildly repellent quality "
] | [
"Are you asking why ice is slippery? ",
"Wikipedia discusses it.",
" We don't know. It might be that ice doesn't hold together well when in contact with air, so the surface of the ice behaves like a liquid."
] | [
"Wikipedia discusses that. The effect is too small to explain how slippery ice is."
] |
[
"So yesterday, my friends and I discovered a pretty large turtle in our neighbors' front yard. We took it down to a creek and released it. This morning, the same turtle was back! But this time...she's up to something. Does anyone know what is going on here? (Album inside)"
] | [
false
] | Like I said, we found it again this morning after taking it 200+ feet down into a creek. It couldn't have been too easy for her to get back up. We're assuming that she's getting a nest ready to lay eggs. If that's the case, can someone identify the species and give us some species-specific advice on watching the nest f... | [
"She looks like a Common yellow bellied Slider turtle. Very closely related to the popular aquarium species \"red eared slider\"",
"She is nesting.. leave her alone, i know in Colorado at least it is against the law to muck around with nesting turtles.. ",
"in 2-3 months the eggs will hatch",
"http://en.wikip... | [
"couldn't hurt to put some wide mesh chicken fencing over the site, to keep animals from digging it up, but allow the hatchlings to get out. ",
"Also, give a lady some privacy, jeez."
] | [
"That's a great idea. I'll talk to the roommates about it. She's laying about 15 feet from the road, I don't think she's too worried about privacy. Haha",
"At first she was looking at me like \"... really? Take a picture, why don't you?\"",
"I thought she had a fantastic idea!"
] |
[
"Feynman explained that he viewed the first atomic bomb test by standing behind a glass window saying that the UV rays are polarised by the window and it would not hurt his eyes. Is this true?"
] | [
false
] | Why can't we just stare at the sun through a car window in that case? | [
"Polarization has nothing to do with it. What he claimed was that he did the math and realized that a sheet of glass would block enough UV that he could safely see the bomb without eye protection.",
"The brightness can still be damaging (as anyone who deals with high power lasers will warn you), but apparently at... | [
"Brightness definitely causes damage. You can easily blind yourself with a powerful visible light or even infrared laser."
] | [
"I don't know if the story is true but glass is a very good protector from UV light - it's virtually impossible to get a suntan through glass.",
"\nYou can't stare at the sun through a window because it's just too bright and damages your eyes. It's not the UV component of sunlight that does it, it's just the shee... |
[
"Does metabolism directly correlate with average lifespan in animals?"
] | [
false
] | It seems to me that animals with much slower metabolism seem to live much longer, but is that actually the case? | [
"Your observation is correct! ",
"That's one of the oldest known variables affecting the average lifespan of a species. Something like a shrew which spends its time frantically searching for food to fuel its rapid metabolism lives a much shorter life than something like an elephant which lives a slow easy lif... | [
"That's interesting!",
"\nI haven't seen that work. I'll have to look into it.",
"\nThanks!"
] | [
"That's interesting!",
"\nI haven't seen that work. I'll have to look into it.",
"\nThanks!"
] |
[
"Why don't we have cars with turbine engines? Will the turbine engine ever be more efficient? How so?"
] | [
false
] | In the 60s Chrysler made a car. | [
"1) Production costs. 2) Maintenance costs. 3) Turbines operate best at a single speeds. Cars would require a sophisticated transmission. Turbines take time to spool up, that's why they are best if operated for long periods at a single speed. 3) Turbines are not efficient at idle. 4) You don't enjoy the power-to-w... | [
"I'm an engineer with a strong interest in aviation. My father is a retired Navy pilot and I'm a private pilot that has built experimental aircraft. I have worked for UPS, DHL, and Saudi Arabian Airlines. "
] | [
"Many of these problems would be overcome by using the turbine to power a generator that would feed batteries that would power electric motors. Single speed, spool up, idle efficiency, startup time. Not sure if you could make it more efficient though."
] |
[
"A question about photosynthesis improvement."
] | [
false
] | Now, what I know is that leaves of a plant are green because they only reflect the green light spectrum. Thus we see it as green. Because of this, photosynthesis can only occur most efficiently at the red and blue spectrum of visible light. So a bit of the white light form a bulb or the sun is wasted and being reflecte... | [
"Plants could absorb more energy if they were black, but it's not as simple as adding black dye. Photosynthesis is a complex reaction with many phases that squeezes out some really pretty incredible efficiency. If you had a different dye for which you could design a similar set of reactions but for a different sp... | [
"Photosynthesis is an extremely complex biological process that centers around chlorophyll pigments. These pigments aren't just color. They're specifically able to absorb light than transfer that energy into an electron transport chain that uses it to make ATP and NADPH. ",
"In order to have a black plant you wo... | [
"Photosynthesis is not very efficient. See this ",
"paper",
". \nC3 plants are 4.6% efficient and C4 plants are ~6% efficient.",
"Laboratory solar panels are in the 40ish percent range. "
] |
[
"How does active noise cancellation work?"
] | [
false
] | null | [
"Noise is just sound.\nSound is waves.\nWaves stack on top of each other, ie interference.\nIf the negative of a wave is added to that wave, they cancel.",
"Soo... assuming the following is a wave.\n5 8-1-3 4 0",
"Then the canceling wave would be\n-5-8 1 3-4 0.",
"Added together\n0 0 0 0 0 0",
"You just out... | [
"On my headphones, loud noises still prevail. would canceling louder noises need louder canceling waves? would louder canceling waves be damaging to the ears?"
] | [
"Isolated noises cannot be canceled because the system needs to create the noise wave in order to create the anti wave"
] |
[
"Is boiling hot water more effective at killing bacteria than a dish soap?"
] | [
false
] | null | [
"There are a lot of factors that go into this and it's impossible to answer the question without defining things more strictly.",
"Dish soap will absolutely disrupt cell membranes for bacteria, but its effectiveness will vary depending on the soap's concentration. Boiling water is a very effective disinfectant, b... | [
"I think it's important to note here that the purpose of most dish soaps isn't to kill bacteria, but to act as a surfactant. This allows the user to more effectively wash away dirt and contaminants as opposed to using water alone, thus greatly reducing the number of bacteria present on the object being washed."
] | [
"To add to this, there are bacteria who can survive boiling for several minutes in a spore state. ",
"Anthrax is apparently one",
", and the more well-known example is ",
"Bacillus cereus",
", notorious for infecting fried rice which is stored for long periods at room temperature after cooking. A brief sear... |
[
"When we have widespread Covid-19 vaccination, how will scientists track the prevalence if everyone has antibodies?"
] | [
false
] | Is it possible? Is it even necessary? Presumably infections can still be identified but only if it's active. | [
"Often we can develop serological tests to distinguish antibodies from infection vs antibodies created through vaccination. Look at hepatitis for a good example of a series of tests that let's us look at active infection vs chronic infection vs vaccinated vs recovered infection. ",
"Antibodies are also only one w... | [
"Thank you!"
] | [
"Will these serological tests be developed and available for Covid?"
] |
[
"The backwards nature of human thought."
] | [
false
] | null | [
"It's the same question as to why people use drugs, eat unhealthy food, smoke cigarettes, drink caffeine. The brain releases certain neurochemicals (e.g. dopamine, serotonin) in response to the drug interacting with the brain. In a lot of people, this makes them feel good/happy/energized/relaxed and for a fleeting ... | [
"That's a very interesting way of looking at it, I never really thought about it like that, the food example works particularly well from my point of view (I do really enjoy lots of food!). But to go out to get insanely wasted seems a bit extreme, considering the severe psychological, health and in many cases reput... | [
"That's a very interesting way of looking at it, I never really thought about it like that, the food example works particularly well from my point of view (I do really enjoy lots of food!). But to go out to get insanely wasted seems a bit extreme, considering the severe psychological, health and in many cases reput... |
[
"Is it theoretically possible to broadcast on an EM spectrum without 'bleeding' over into other spectrums regardless of power. If not, why?"
] | [
false
] | If it's theoretically possible what's so difficult about pulling it off? | [
"In principle, you could transmit a single constant frequency sinusoidal signal which wouldn't interfere with any other band*. Lasers do this. However, transmitting a single continuous tone would not allow you to transmit any information. This would require the signal to be varied in some way, say switching it o... | [
"Generating very narrow bandwidth radio waves is completely possible, however the density of a spectral band isn't completely determined by this. By \"broadcast\" I assume you're talking about some form of communication, by some sort of modulation. Frequency modulation is the most commonly used because it has supe... | [
"Sure. Look at the uncertainty principle. You can either be certain about position or momentum, but not both. For a photon, momentum relates to energy, which relates to frequency. All EM signals are just photons. If you want to know exactly which frequency you are broadcasting, you'll have to send it everywhere. A ... |
[
"Seeing our own galaxy and pinpointing earth?"
] | [
false
] | [deleted] | [
"It's not. The pictures you refer to are artists' impressions, or possibly composite photographs of distant galaxies thought to vaguely resemble our own.",
"Imagine being an ant crawling on a painting in the portrait wing of a museum. You would have a much easier time seeing other paintings hanging elsewhere in t... | [
"The galaxy is not the milky way but some other galaxy (Andromeda?) with an arrow randomly pointing at some star that has roughly the same distance to the galactic center as we do. We don't have a proper picture of our galaxy except ",
"this one viewed from the side",
" and ",
"simulations/artist's impression... | [
"That's the M31 galaxy, in Andromeda. It's about two and a half million light-years from here, it's thought to be about 40 percent larger than our galaxy and it's believed to contain more than twice the number of stars.",
"That image was, doubtless, made by someone who was trying to be cute.",
"Edit: Million, n... |
[
"How do high voltage power lines simultaneously have high voltage and low current?"
] | [
false
] | It is pretty straight forward that decreasing the current flowing through a transmission line also decreases the loss of power from transmitting through that line due to: P = I^2*R P: Power Lost I: Current R: Resistance Every source that I have found states that current is decreased in long distance power transmission ... | [
"You are thinking about this the wrong way. An electrical system needs to deliver a specified amount of power, so we need to find out what combinations of voltage and current give the required power. For this, we use the expression P = I·V. Rearranging it to I = P/V shows that for fixed P, higher V produces lower I... | [
"That's not his confusion. He's right to apply V = RI, and he's correct to determine that lowering the current also drops the voltage. The voltage does in fact drop, this is true. ",
"But ",
" voltage is his issue that's he's thinking about the wrong way. The voltage in question he is looking at is the voltage ... | [
"If the voltage is increased shouldn't the current also increase, not decrease?",
"There's transformers everywhere in AC power distribution.",
"Even if the final load ",
" a resistor, the apparent resistance on the other side of the transformer is multiplied by N² where N is winding ratio.",
"For example, i... |
[
"Are electromagnetic waves from television sets and computers still harmful?"
] | [
false
] | I remember when I was younger, my mom always told me never to sit too close to the television screen (Stay at least 9 feet away?) because of the electromagnetic waves emitting from the screen and it can cause radiation and you loose your vision. I was told the same about computers but I remember when I had my windows 9... | [
"It was never true in the first place. TVs can cause eye strain but no actual eye damage no matter how long you watch or how close you sit. This was an old wives tale that has been around since the invention of television as far as I know. Electromagnetic waves in the part of the spectrum we are talking about he... | [
"Very old CRT TV's used to emit Xray radiaton. Modern Cathode Ray Tubes have special glass and overvoltage protection to prevent Xray, but still some coils can emit very strong low frequency radiation.",
"http://en.wikipedia.org/wiki/Cathode_ray_tube",
"LCD screens are safe and don't emit harmful radiation, but... | [
"Your mom was full of shit. Sorry bro. "
] |
[
"If two black holes were so close that their event horizons overlapped, and an object was placed in a location where it is in BOTH event horizons, what would happen to the object?"
] | [
false
] | Inspired by questions in this thread- Anything inside the event horizon of a black hole is assumed to be lost forever, constantly moving towards the singularity with no hope of escape. But could an equal or greater force coming from outside of the event horizon possibly have a chance of extracting the object? Edit- Sho... | [
"Nope.",
"I get the feeling you used newtonian intuition to come up with that answer.",
"\nI have little to add to this thread, except that I doubt any of the answers yet posted are anything more than speculation...",
"Having taken a basic introductory course on introductory GR for dummies, I can at least say... | [
"Nope.",
"I get the feeling you used newtonian intuition to come up with that answer.",
"\nI have little to add to this thread, except that I doubt any of the answers yet posted are anything more than speculation...",
"Having taken a basic introductory course on introductory GR for dummies, I can at least say... | [
"Nope.",
"I get the feeling you used newtonian intuition to come up with that answer.",
"\nI have little to add to this thread, except that I doubt any of the answers yet posted are anything more than speculation...",
"Having taken a basic introductory course on introductory GR for dummies, I can at least say... |
[
"Would it be possible for a virus to produce infertility in humans?"
] | [
false
] | I've read a few science fiction books that have talked of viruses that produced infertility and I was wondering if it were possible for a virus to actually produce infertility or if it's a purely mythical concept. Edit: I placed this in biology figuring that the question would belong there, but please let me know if it... | [
"There are plenty of pathogens that can adversely affect the reproductive systems. For example, the mumps virus (now rare due to vaccination) is typically associated with a parotitis (inflammation of the parotid glands in the face), but can also cause orchitis (inflammation of the testes). ",
"This can lead to ... | [
"Lymphocytic choriomeningitis - Ranges from mild flu-like illness to biphasic with meningitis in second phase; arthritis, parotitis, and orchitis may occur; can be teratogenic (CNS) or cause abortion; rarely fatal in immunocompetent. ",
"(take from ",
"http://www.merckmanuals.com/vet/zoonoses/zoonoses/zoonotic_... | [
"Just to be clear to the OP- gonorrhea and chlamydia are caused by bacteria and not viruses. Bacteria are much more common causes of PID, but it ",
" be viral. People are also at a ",
"much greater risk",
" of getting PID from a bacteria when they are already immunocompromised from HIV, so in that sense the i... |
[
"Has anything ever fallen into a black hole (from Earth reference frame)?"
] | [
false
] | My understanding is it would take an infinite amount of time to observe any matter falling into a black hole, so nothing will *ever* be observed falling into a black hole. Yet, black holes can grow? How? | [
"It would appear as if, from the outside observer's view (say, from Earth) the point of actually falling into the singularity never happens.",
"https://www.quora.com/How-has-anything-ever-fallen-into-a-black-hole"
] | [
"For things falling in you'll quickly receive the last photon ever. Microseconds for stellar mass black holes, up to hours for the most massive black holes we know, but either way it is a relatively quick process. Has the object fallen in afterwards? That is more a philosophical question because general relativity ... | [
"We only, for the first time in history, have actually imaged a black hole in the last few months. And it's a super massive so ridiculously far that it's not exactly a detailed picture. ",
"If we could get close enough /have better tech what we'd find is ,likely, things dissappear before they 'enter'. The light s... |
[
"AskScience AMA Series: We're marine scientists exploring the deep sea off Cabo Verde sailing on board the iMirabilis2 cruise. Ask us Anything!"
] | [
false
] | We are a team of scientists and technicians sailing on board the Spanish research vessel on a four-week cruise to explore Cabo Verde's deep sea ecosystems. On board we have the remotely operated vehicle (ROV), Luso, the autonomous underwater vehicle (AUV) Autosub6000, three benthic landers (a respirometer, baited camer... | [
"Hi! ",
"As most of the deep-sea is vastly unexplored, the chances of finding new species on board of a deep-sea scientific expedition are actually quite high! ",
"During a ROV dive, we sampled a scleractinian coral that we think it could be a new species to science. However, as we don’t have any coral taxonomi... | [
"Hi – Murray Roberts here",
"I’ve been lucky enough to dive in two submersibles – the Johnson SeaLink off the southeast USA and the JAGO submersible off Norway. It’s tremendously exciting to visit the habitats you’ve spent years studying and finally see them with your own eyes. You get a real sense of how the hab... | [
"Are there any new lifeforms you have discovered yet?"
] |
[
"Why are tides different heights?"
] | [
false
] | null | [
"The size of the tides depends on a number of factors. Of course, the most dominant factor is the gravitation pull of the moon. You will get two high tides: one roughly* when the moon is overhead, and another when the moon is on the opposite side of the Earth. The low tides happen in between the tidal bulges. The h... | [
"The tides are not only vertical, there is also horizontal movement which causes a timing difference.",
"\nIf you look at the ",
"Bristol Channel",
" then the flow going into 'the funnel' will create a higher tide at the narrow end, compare ",
"Pembroke",
" (Irish Sea side) with ",
"Swansea",
" in the... | [
"Yes, and it could be even more interesting with the Atlantic having direct access from the North, the Irish Sea being a small-ish restriction from the South, and the Earth's rotation having a mind of its own regarding the direction of the ",
"flow",
"."
] |
[
"How different are types of cancer?"
] | [
false
] | To my knowledge cancer is unrestricted cell growth. Is there some difference between pancreatic, breast, or brain cancer? Bonus question: if cancers are similar wouldn't it be more beneficial to direct donations through one channel of giving rather than having organizations giving to multiple, more specific researchers... | [
"Yes, you're right. Cancer is essentially when a cell gains a mutation that allows it to grow too much and/or escape normal death mechanisms. There are dozens if not hundreds of different genes and protein products involved with cell growth and cell death. For example, a couple of the major oncogenes (genes that... | [
"There are both similarities and differences - that is not a question that can be answered in any definitive way.\nYou can look at similarity in mutations, for example almost all cancers will mutate or delete the p53 protein while turning up the Ras protein. Cancers that metastasize to the same location, such as th... | [
"There are often very significant differences between cancers due to location. These differences affect treatment, diagnosis and outcome hugely. Location is also not the only difference, the specific mutation(s) will contribute to how the cancer responds to a particular type of treatment (and plays into targetted t... |
[
"How i can calculate the chi-squared distribution table values?"
] | [
false
] | null | [
"You can use the ",
"CDF for the Chi-squared distribution",
"."
] | [
"So you're trying to find the χ",
" for a given p-value and n? The equation you need to solve is",
"p = 1 - f(χ",
";n),",
"where f(χ",
";n) is the Chi-squared CDF for n degrees of freedom. You know p and n, and f is a known function. You want to solve for χ",
"."
] | [
"It doesn't matter if it's the critical χ",
" or just any value of the χ",
". This will give you what you want."
] |
[
"Why does the diaphragm reverse its motion after phrenic nerve damage?"
] | [
false
] | What exactly makes the affected side of the diaphragm move upwards during inspiration, and downwards during expiration. | [
"Breathing occurs due to generation of negative intrathoracic pressure.",
"Contraction of the diaphragm, internal intercostals and various accessory muscles such as scalenes and SCM will expand the volume thoracic cavity, thus generating negative intrathoracic pressure.",
"A hemidiaphragm that has lost its inne... | [
"Expiration is passive and it's due to your intrathoracic pressure returning to 0, thus your diaphragm returns to its resting position (ie, opposite of going into your thorax). ",
"Try covering your mouth with some saran wrap. Now suck inwards. You'll notice that the saran wrap will slightly curve into your mouth... | [
"Think about what causes expiration. The non-paralyzed side relaxes and the intra-abdominal pressures increase. The paralyzed side is paralyzed so it's only responding to the intra-abdominal pressure. The increased pressure forces it back down."
] |
[
"What is the exact value of Avogadro Constant?"
] | [
false
] | Considering that it is a 24 digit integer (6.022 X 10 it is not like the value of Pi. Everywhere I looked, I was just able to find the value to some approximation. Is the exact value even determinable/known? | [
"The value is determined by our definition, and since we defined it with respect to carbon-12 in their ground state, the precision we can measure it to is limited by our instruments. ",
"Currently, we don't have an exact value because our equipment isn't precise enough. "
] | [
"It will always be the same, because the definition relies on a specific mass of the atoms. If our measurement is slightly different from the definition, then the measurement is wrong. The measured number will only be considered correct if it exactly matches our definition. ",
"Avogadro's number isn't a specific ... | [
"Does that mean that if and when we determine the number precisely, we might find that 1 mole of any element contains slightly less or more number of atoms than C-12? Or is it going to be exactly the same to the last unit?"
] |
[
"Reflex question"
] | [
false
] | Our biology teacher was telling us about the reflex arc (I am not sure about the name of this, because I translated it literally from my native language) in the nervous system, and I asked her a question that she couldn't answer, so I decided to come to reddit to seek my answers. :) So here's the question: | [
"You do react reflexively to a needle stick, but it occurs in the smooth muscle of the dermis. Major reflex arcs (like the patellar reflex) are hard-wired to be much larger in scope. ",
"You wouldn't get very far in life if you flinched massively every time you got poked somewhere. "
] | [
"This makes a great deal of sense. When I think about it, I do sometimes notice a slight spasm in my arm during a shot. Does consciously trying to relax cause muscles to behave differently?"
] | [
"In certain circumstances, yes you can 'override' a reflex. Try holding your hand on a hot stove burner. ",
"NOTE: DO NOT DO THAT."
] |
[
"What research is currently being done to help cure the HSV-1/2 virus?"
] | [
false
] | Not sure if this is the best place to post this, would be happy to delete and post somewhere more appropriate What research is currently being done to help combat the HSV1 and HSV32 virus in humans? Why is it hard to find a cure for this illness? What are the limitations in what can be done, chemically speaking when it... | [
"Im sure that someone with more time will answer this more in depth, but due to the fact that these diseases are not life-threatening and only mild inconveniences to most, there has not been a lot of research compared to other disease States. However there is several clinical trials I believe, that are testing vacc... | [
"There are 2-3 vaccines currently in various stages of development. One by Vical is a bivalent vaccine that is still in the early phases of moving to clinical testing, two others have shown to remove the virus is monkeys and are promising but that word usually means at least another 5-10 yrs before results. Both ar... | [
"While I agree with a lot of what you said, I would mention that herpes can be life-threatening in the cases of herpes encephalitis and in vertical transmission from mother to newborn. "
] |
[
"Dear AskScience, will you please explain quantum numbers to me, please?"
] | [
false
] | [deleted] | [
"n is the principal quantum number. It denotes the shell of the electron. So you have n = 1, 2, 3, etc.",
"l is the orbital angular momentum quantum number. It tells you what ",
" of orbital (subshell) we're dealing with - so l = 0, 1, 2 corresponds to the s, p, and d orbitals.",
"m is the magnetic quantum nu... | [
"A math major, eh. In that case, you know how differential equations have eigenvalue solutions? The quantum numbers are just eigenvalues to the solution of the schroedinger equation. n and l are indices of a spherical harmonic (a Legendre polynomial), and m is just which value of l is selected."
] | [
"Very helpful, thanks!"
] |
[
"I'll be interviewing a senior scientist from CERN next week. What should I ask?"
] | [
false
] | I'm an newspaper reporter. He's coming to my city to do a guest lecture at the university. I try to follow the developments at the LHC, and I understand the basic explanations about the Higgs Boson and the Standard Model. (I mean, I don't it, but I get the very general explanations.) Anyway, can you suggest any particu... | [
"\"What do you expect to find beyond the Higgs?\"",
"And then whatever he answers:",
"\"Really?\""
] | [
"What is his name, btw?"
] | [
"Letting us know his name, and the project he is working would help with what questions to ask."
] |
[
"When your arm falls asleep while sleeping... Is there any biological mechanism that prevents complete loss of vascular/neurological function?"
] | [
false
] | After sleeping on a plane the other day, the position I was in caused my arm to completely fall asleep, I mean completely numb. It took about 5 minutes to regain feeling. Now, I know this sensation is due to obstructed blood flow and/or pinched nerves, but is there any sort of 'built in' mechanism that would wake someo... | [
"Doesn't really seem to happen - no. And this is usually caused by a pinched nerve. The pressure in the arteries should be high enough that there would be a HUGE difference in arm pressure between that necessary to pinch a nerve, and that necessary to cut off blood flow. ",
"When the nerve begins to get pinched, ... | [
"The lateral spinothalamic tract which carries pain has fibers that branch off to the reticular system on its way to the thalamus. Theoretically if the pain is enough the reticular activating system can be stimulated to start waking up the cortex. I mean this is in theory, not sure whether the pain/parasthesiea fro... | [
"I love the explanation, but I just wanted to add something to what you said because people might find it interesting:",
"Normally the sensory axon activity inhibits pain axon activity to prevent heavy tactile stimuli from being perceived as painful.",
"This is the Gate Control theory of pain. The nociceptor af... |
[
"Since the universe is expanding, are dark matter particles expanding or are they growing in number?"
] | [
false
] | null | [
"The amount of ",
"dark matter",
" has AFAIK been constant, but ",
"dark energy",
" seems to be an intrinsic energy of space itself and thus increases as the universe expands. An alternative explanation to dark energy as an intrinsic energy of space is ",
"quintessence",
".",
"I don't know if you can ... | [
"Right, so if dark matter exists -- the dark matter that is gravitationally bound to galaxies just goes along for the ride with the galaxies as they get farther apart.",
"I'll also note that as long as we are talking about alternative theories -- I find MOND at least compelling enough to be kept on the table beca... | [
"if dark matter exists",
"There is ",
"not really a question about that."
] |
[
"Why does an automobile need an engine?"
] | [
false
] | null | [
"Thanks fam.",
"But this begs a rephrasing of the question, then: Why not use a simpler motor with much less component parts to make the car go forward?"
] | [
"Thanks fam.",
"But this begs a rephrasing of the question, then: Why not use a simpler motor with much less component parts to make the car go forward?"
] | [
"Well I don't think so but I don't own an automobile manufacturing plant"
] |
[
"Why did nuclear rocket engines like Project NERVA and Project Timberwind use liquid hydrogen as fuel?"
] | [
false
] | There have been several experimental projects using nuclear reactors provide thrust by superheating liquid fuel (and another was recently funded). All of these projects used liquid hydrogen as propellant. Why not something more dense and less volatile like liquid helium or liquid argon? Is it because of thermal expansi... | [
"Hydrogen produces the best specific impulse because it has the lowest mass of any neutral molecule. Lower mass means that at a given temperature, the average velocity of the particles is higher, and exhaust velocity is what governs the efficiency of a rocket engine.",
"Helium has a much lower boiling point meani... | [
"Energy is cheap in a nuclear rocket, so running hot enough to dissociate the hydrogen is a good thing if you can do it. Better exhaust velocity. The difficulty is making a nuclear reactor that can run super-hot. NERVA actually ran cooler than many chemical rocket engines, but still had much greater exhaust velocit... | [
"The top comment is referring to this equation: ",
"https://en.wikipedia.org/wiki/De_Laval_nozzle#Exhaust_gas_velocity",
"Exhaust velocity is directly proportional to the square root of temperature and inversely proportional to the square root of molecular mass. Therefore, even if pressure were kept equal, lowe... |
[
"If the colors we see are just the wave length of light that is not absorbed by the object, int he absence of light is everything the same color?"
] | [
false
] | a blue shirt is blue because it does not absorber blue light and instead reflects it. If we put this blue shirt in a completely sealed environment and shot all colors of light at it other than blue ( if it were possible) what color would it be? Does this vary from color to color? | [
"It'd look black under that light. The lack of color/light is black. It means your eyes/detector isn't getting any signal.",
"Also, real shirts aren't perfect absorbers/diffuse reflectors, you'd still \"see\" the shirt, it wouldn't be a void in your perception, but it wouldn't look blue simply because they're no ... | [
"You could do something like this in real world fairly easily. All you need is a good laser pointer and a shirt of some color other than that of the laser. Just go into a central room in your house, turn the lights off and shine the laser at it. It probably will not be perfectly black but it should be enough to see... | [
" is a sensory quantity, not a physical quantity. It is an approximate representation of some of the spectral characteristics of an object. You can indeed make a blue shirt appear to be any color, by illuminating it differently. Perception of color has a bunch of feedback in it that has evolved to separate illum... |
[
"How are pictures like the Hubble Deep Field taken with such fine focus with the telescope moving at tens of thousands of miles per hour?"
] | [
false
] | [deleted] | [
"The things it's taking pictures of are so far away that they move very little within the telescopes field of view. It's the same way that when you're driving on a highway, trees on the side of the road flash by in an instant while mountains in the distance move much more slowly. It would be impossible to take a pi... | [
"The biggest concern is rotation of the telescope, not position. As long as the telescope isn't rotating, it'll nab a clear picture."
] | [
"The biggest concern is rotation of the telescope, not position. As long as the telescope isn't rotating, it'll nab a clear picture."
] |
[
"Mathematics/Numerical Analysis: Estimating/Approximating an unknown function from a set of known integration results?"
] | [
false
] | So here is the problem I've been thinking about. I apologize in advance, I don't know how to make mathematical markup on reddit. Please feel free to ask for clarifications if needed. 1) Let f(x) be some function with the following properties: * f(x) has finite support over some known interval, S. * f(x) is everywhere n... | [
"This is a (discretized) integral equation of the first kind. The solution method you describe is known as a quadrature method. The problem with this method is that, if P(x,y) is continuous, then the matrix P_{ij} will be very poorly conditioned as you take a finer discretization. This is easy to see by noting t... | [
"This sounds like a classical approximation problem to me. Especially if you are allowed to cloose your ",
".",
"So you have ",
" different functions ",
"(",
") (I have emphasised here that your ",
" is just a parameter and only the pointwise behaviour of ",
" matters to the problem—essentially these ... | [
"only the pointwise behaviour of y matters to the problem - essentially these are N different functions",
"This is a dangerous assumption if P is continuous. If P is continuous, then each of the functions P_j that you used in your solution will be very similar to eachother and your matrix, A, will be very ill-co... |
[
"I know this smacks of Lamarckism but is it at all possible to change your genes or alter your DNA after you're born?"
] | [
false
] | null | [
"Depends on what you are really asking.",
"\n If you are asking if DNA undergoes significant changes from the time point your first cell is formed to the pont when you shuffle off this mortal coil. Yes, and in in several ways. Epigenetic modifications (extra layer of information in methylation of DNA), VDJ rearra... | [
"Yes and no.",
"No, you can't simply change your DNA sequence yourself.",
"Gene therapy can currently change the DNA sequence of SOME of your cells (although we're working on making it all of your cells). Unless this affects your gonads in the right way, these changes will not be passed on to your children. Thi... | [
"Thanks. I just transferred to studying genetics and I'm really fascinated by this sort of thing."
] |
[
"In case of a fierce Solar Wind Storm, What protection strategies can be adopted?"
] | [
false
] | I watched the video about STEREO, we're now able to see the whole sun for the first time in Human History. As it is a step toward implementing a weather forecast system for Solar Wind Storms. Hence, NASA must have a strategy to protect earth from Solar Wind Storms. I was thus curious, what can be done at times when we ... | [
"Sun's solar flare activity reaches it's peak at period of 10 years which fixes the next peak in 2012.",
"It's actually a dipole cycle of approximately 25 years, with significant variation. The last minimum happened in late 2008, and the next maximum is projected to happen in mid-2013, but these predictions are e... | [
"Rescue people from what? Unless you are outside the Earth's magnetic field solar flares pose very little risk to humans. In the case of a giant solar flare everyone should go north to watch the Aurora Borealis."
] | [
"Well, the ",
"last big solar flare",
" toasted all electronics of that time (telegraphs). Today world would end if all electronics were burned down, so that's quite a big risk. Of course, I'm not an expert here, so I was hoping that maybe you could enlighten us..."
] |
[
"How do you perform an eye test on a baby or toddler when they can't communicate verbally?"
] | [
false
] | null | [
"There are numerous ways to perform an eye exam on anyone who is non-verbal or does not speak the same language as the doctor, not just babies and toddlers.",
"There are autorefractors that use infrared lasers to measure how much light is refracted as it moves through the eye and takes this information to provide... | [
"I've been to like 10 different optometrist so far... including for myself and accompanying friends and family members who had to. They usually all use that method at first. But it gives only a rather vague estimate about the needed correction. Usually you start from there with fine tuning. Usually they show you a ... | [
"Why not do this for everyone's exams? Cost? "
] |
[
"How does the rotation of the earth affect air travel?"
] | [
false
] | When you take a flight, one can imagine how you can either fly along with the rotation of the earth or against it. Yet a quick google search shows, a flight from New York to Tokyo is about the same time as a flight from Tokyo to New York. Why is this, and how exactly does the rotation of the earth affect our air travel... | [
"it has an effect due to the winds, and those winds blow the way they do largely due to the rotation of the earth (and how the sun heats up a portion of the earth as it (the earth) rotates under it).",
"It is quite a significant effect at mid latitudes. For instance, a flight going east is probably 25% or so qu... | [
"The simple answer as to why the rotation of the earth doesn't directly impact travel times by air is that airplanes start out moving at the same speed as the ground. So they have no problem traveling with or against the rotation of the Earth because they're already in a rotating Earth-centric reference frame. ",
... | [
"Imagine you're in a helicopter on the ground. You fly straight up, and hover for 4 hours. Where do you land? Answer is more or less the same spot you took off from, not 4 rotational hours distance away - the whole planet, including the air, is moving at roughly the same speed. Winds will effect air travel times, ... |
[
"Are superposition and wave-particle duality related? If so, how?"
] | [
false
] | Intuitively it seems like they should be somehow related because they are both fundamental to quantum mechanics (right?) and they both deal with objects that are simultaneously both one thing and another, but I have never read anything that directly connects the two or refutes a connection. | [
"It's complicated by the fact that there are multiple senses in which the \"particle\" nature of particles is manifest. For example, even in a pure-wave theory it can still be that there is a wave of smallest possible amplitude for a given frequency (ie waves come in quanta). For example in the quantum theory of el... | [
"I have a few further questions if I may.",
"In images of particle collisions in particle accelerators you see particle trajectories (both straight and curved). How is it possible to measure an entire trajectory? Doesn't this contradict the Heisenberg uncertainty principle?",
"In classical mechanics the state o... | [
"In images of particle collisions in particle accelerators you see particle trajectories (both straight and curved). How is it possible to measure an entire trajectory? Doesn't this contradict the Heisenberg uncertainty principle?",
"We cannot measure the trajectory perfectly. But we can measure the trajectory pr... |
[
"Are 98% of the atoms in the human body replaced every year?"
] | [
false
] | In my World Religions class, the teacher presented an article that stated that 98% of atoms in the human body are replaced every year. This was to spark a discussion about whether "we are this body" or whether we have some kind of spirit soul. The direct quote from the article is: Studies at the Oak Ridge Atomic Resear... | [
"It seems to have some good basis in experiments conducted by some dude called Paul Aebersold back in the fifties:",
"http://www.time.com/time/magazine/article/0,9171,936455,00.html",
" (Note the date on the article: 1954!)",
"I'm not surprised that it's a high percentage (the watery bits of your body should ... | [
"You may find ",
"this interview from NPR",
" relevant:",
"KESTENBAUM: McCarthy did some research and he found this article from a Smithsonian Institution publication from 1953. So this is the beginning of the Atomic Age. And the article described these experiments where researchers fed to people radioactive ... | [
"I looked around for an answer to this, but I couldn't find the original article cited, which was in Annual Report for Smithsonian Institution in 1953.",
"This article, I think, sums up the discussion of it though: ",
"http://stevegrand.wordpress.com/2009/01/12/where-do-those-damn-atoms-go/"
] |
[
"Why is there vapor that comes off really cold things?"
] | [
false
] | null | [
"It's the result of atmospheric water vapour condensing into droplets."
] | [
"I imagine you are talking about what you may see if you pull out a tub of ice cream from the freezer on a warm day you see little wisps coming off of the fridge and the object. Well it's not necessarily coming off of the object itself. The object has a certain temperature which will tend to cool the air surroundin... | [
"Sure, let's give it a go. The molecules within the ice cream (let's say you have a bowl of it and are observing OP's description) are moving rather slowly compared to the air molecules (solid vs gas but also lower vs higher temperatures). We have vibrations in the ice cream and vibrations ",
" rotations in the a... |
[
"Why is the maternal death rate due to childbirth on the rise in the US?"
] | [
false
] | My wife has jumped on the home birth bandwagon, and during one of the shows there was the statistic that the amount of mothers who die from giving birth in the US has doubled in the past 25 years. I've looked up at the stats and they appear to be correct, but what I can't find is the reason behind it. The TV shows sugg... | [
"Not a peer-reviewed journal, but here is an article that had something to say:",
"Doctors say pregnancy has become increasingly risky for several reasons: the prevalence of obesity, Type 2 diabetes, hypertension and cardiovascular disease; more older women having children; advancements in fertility treatments re... | [
"C-sections can be indicated for a number of reasons (it is a long list) but know that it is either because the baby's life is in danger, the mother's life is in danger, or both.",
"All medical decisions come with risk/benefit considerations. All we can do is let the patient know what those are and let them choos... | [
"Correct. Older mothers who are more likely to be obese. They require more interventions and have higher complication rates"
] |
[
"Does the gravitational pull of the moon affect anything other than the tides?"
] | [
false
] | Obviously the moon has a huge effect on the oceans, but does it have a large effect on anything else? | [
"not to mention as it \"deforms\" the Earth it produces a lot of stress and strain, which in turn causes the earth to heat up and is one of th major factors that makes our planet have a molten core which in turn keeps our magnetic field and protects us from the solar flares from our sun. Its safe to say the moon ha... | [
"It ",
"deforms the earth",
". It makes the ",
"earth rotate slower and the moon move away",
". It ",
"stabilizes earth's axis",
" and makes it ",
"precess",
"."
] | [
"is one of th major factors that makes our planet have a molten core",
"I wonder how big that factor is. Wikipedia says it's ",
"2.5 terawatts",
", which would be more than 5% of the alleged ",
"44.2 terawatts",
" heat loss of the earth, although this Wikipedia article says it's \"residual heat from plane... |
[
"Do different types of alcohols effect the body differently?"
] | [
false
] | I ask this because from personal experience and with others I've talked to, we all agree there's a difference. For example, when I drink dry gin I get a whole body drunk, vodka will give me a sloppy "head" drunk, tequila destroys me in the morning every time and whiskey makes me wake up. I was wondering if there's any ... | [
"A similar question has been asked before. I believe the ",
"top response",
" has the information you are looking for."
] | [
"I thought we'd be comparing isopropyl, methanol, ethanol....",
"In which case the answer is definitely yes. Methanol can cause blindness in excess, which is why freeze distillation is dangerous. Methanol will evaporate quicker than ethanol during hot distillation methods."
] | [
"I thought we'd be comparing isopropyl, methanol, ethanol....",
"In which case the answer is definitely yes. Methanol can cause blindness in excess, which is why freeze distillation is dangerous. Methanol will evaporate quicker than ethanol during hot distillation methods."
] |
[
"When you get sick, where are the germs physically located in your body?"
] | [
false
] | To clarify, I am wondering if the germs are cycling through your bloodstream, concentrate in one area, or some other option I'm not aware of. | [
"I would imagine this is dependent upon what sort of illness you have. For example — I once had a massive infection in my knee. The infection created this massive amount of junk (dead white blood cells, infection, that sort of thing) that needed to be surgically removed. It was located in my knee, just where I woul... | [
"Entirely dependent on what the pathogen is. Bacteria, for example, are very diverse in where they like to travel/stay when infecting us, and many different evolutionary traits have accompanied this microbiological divergent evolution. ",
"A lot of bacteria have no mobility and instead prefer (or maybe are forced... | [
". The common cold is caused by viruses, which multiply in the bloodstream and travel evenly throughout the body. ",
"Nah, that's not right.",
"Common cold is caused by rhinoviruses, which mostly infect epithelial cells in the upper respirtatory tract.",
"You can occasionally get these viruses in the blood, a... |
[
"What is the smallest change in color humans can detect and what is the limiting factor to it being smaller?"
] | [
false
] | [deleted] | [
"It is called a ",
"Just Noticeable Difference",
" and it is a statistical difference established under controlled testing. A ",
"MacAdam Ellipse",
" is a region on a chromaticity diagram which consists of colors which are indistinguishable from each other. Humans can detect changes more readily in ",
"da... | [
"Look up tetrachromacy and learn how some people (women only) with a genetic difference can discern a much greater number of colours (they have 4 kinds of cones in their eyes, responding to 4 different wavelengths of light instead of the 3 that everyone else has, so this is one of the limiting factors you ask about... | [
"The only way to understand what color is actually meant is by studying the language and culture.",
"What I meant with the Himba tribe is that they were given 12 squares. 11 squares were green, and one square was blue. They were incapable of discerning which square was blue. ",
"When the blue square was replace... |
[
"What happens to excess electricity/energy created by solar panes/turbines/hyrdo, etc.?"
] | [
false
] | Sorry, repost since my question got removed for requesting a simple explanation in the vein of a similar subreddit, but: My question has two parts to it: -How is electricity stored on a very large scale, such as the grid? -What does it mean when there's 'excess' energy produced by certain electricity-producing energy ... | [
"1.",
"\nIt really isn't stored. The power company generates as much power as is instantaneously needed, and no more. They have very good forecasts on how much power is needed on a minute-by-minute basis. ",
"See this page",
" for California forecast demand. They have certain types of power plants that ar... | [
"So....",
"You are Poseidon (the power company), and you control how much water (power) flows down a particular river (the grid). People who live on the river power their homes with a waterwheel in your river. Every waterwheel slows down the flow of the river, because it's essentially taking energy from the river... | [
"So....",
"You are Poseidon (the power company), and you control how much water (power) flows down a particular river (the grid). People who live on the river power their homes with a waterwheel in your river. Every waterwheel slows down the flow of the river, because it's essentially taking energy from the river... |
[
"What career choice makes the highest percentage of people happiest?"
] | [
false
] | EDIT: Just want to clarify that I am looking for jobs that correlate with people being happy in day-to-day life. I'm not necessarily looking for jobs that result in stress-free life (not the same thing) or job satisfaction. And before anyone says it, I know correlation doesn't necessarily imply causation. Still, I'm in... | [
"Happiness is difficult to measure, though one component of it could be lack of stress.",
"A ",
"survey",
" was done for least stressful jobs and the top 10 were composed of computers, math, and healthcare."
] | [
"That is completely personal and subjective then. Happiness will only come from what YOU want, no one will ever be able to tell you what job will fit that, at least without and depth analysis of your traits and passions. Check out sites like career cruising,and they help you identify what jobs you will be satisfied... | [
"IO Psychology MSc. (I study the psychology of people at work). Interesting question here but hoping to get some more info before I dig into the research. When you say \"Happy\" what are you looking at? Like, day to day happiness (positive affect), happiness with the job itself (job satisfaction), some form of fulf... |
[
"How do we get earthquakes In Australia if we're not really close to a tectonic plate?"
] | [
false
] | [deleted] | [
"To be specific, you are, everywhere on earth at least, close to a tectonic plate because you are on one. In Australia you are not close to a plate boundary. The type of earthquakes you are describing are typically referred to as \"intracontinental earthquakes\" or \"intraplate earthquakes\" more generally. Intrapl... | [
"There are fault lines all over the planet's surface, not just along major tectonic plates. ",
"Here's a fault line map of the US",
". I couldn't find one for Australia, but this map shows that there are a lot of fault lines all over. And these are only the major ones. ",
"There are thousands of minor fault l... | [
"Nevada and Utah are swarmed with the Basin and Range province normal faults, but what's happening on that Sandia fault down in New Mexico? Is that also normal faulting from the Miocene extension?"
] |
[
"What is the maximum distance that a metal object can reliably be held in place by a magnet?"
] | [
false
] | Hey everyone, this question was formulated after taking a mechanical engineering control systems class this semester. Though the course is now behind me, the seed of an idea for a side project (inspired by one of our graded projects) has taken root in my head. I've been doing some googling around and tried to crunch so... | [
"Well it depends on how large and strong your magnets are, with rare earths they can get very strong. If you want even stronger you can get superconducting coils ha ha. But essentially, from my limited understanding, magnetic fields decay with the cube of distance, which means their strength is quite limited, and t... | [
"Wait, it's not inverse or inverse square? Not doubting, but I'd like to read more about that if you have a source"
] | [
"https://www.physicsforums.com/threads/magnetic-field-strength-diminishes-proportional-to-inverse-cube-or-inverse-square.450414/",
"https://www.quora.com/Why-does-the-magnetic-field-obey-an-inverse-cube-law"
] |
[
"How long would it take for the effects of global warming to reverse if all human activity stopped?"
] | [
false
] | If all humans disappeared from earth how long would it take? | [
"Our best \"experiment\" with changing the earth's climate the way we're doing now is the ",
"Paleocene-Eocene Thermal Maximum",
". This was a natural release of carbon into the atmosphere, likely involving methane hydrates, which caused ~6C of warming. We're not at that level yet, though if we accidentally kic... | [
"There is consensus that we are causing global warming. "
] | [
"There ",
" consensus that we're causing global warming. The ",
"anthropogenic contribution to the warming",
" over the last 50 years is estimated to be 100%, for the last 100 it's about 50%."
] |
[
"Do acidic and alkaline foods effect the ph of the blood? If so, what physiologically is happening during that and what is happening to balance ph?"
] | [
false
] | I am a very fit person and was at my dentist today. The hygienist says something like "must have a good dietician and get good exercise." While she is doing my dental work, she starts talking about using lemons to make your blood more alkaline. She said other things too that I feel like are nutritional psuedo-science, ... | [
"There's some current fad in diet circles about 'alkaline diets'. It's complete nonsense and it's been debunked here a number of times. I recognize the whole 'lemons are alkaline' claim from it. ",
"Short answer is that your food does not significantly change your blood/body pH at all. Quite obviously there's som... | [
"To say that you can't alter it by eating is false. You can alter it by eating, but not in the simplistic way of eating acidic and alkaline foods. Diabetic ketoacidosis occurs when one's diet or circumstances lead the body to break down alternative sources other than sugar for energy, leading to an excess of keto... | [
"The skeletal structures can play a role in pH buffering, but that's in the phosphate buffering system. Other buffer systems in the body include proteins and hemoglobin.",
"Carbonic acid and bicarbonate can be regulated by the respiratory system and/or by the renal system. Carbonic acid is formed from CO2 in th... |
[
"Why is the graph of the price elasticity of demand parallel when it's perfectly elastic?"
] | [
false
] | Given a graph where in the x axis we have Quantity and in the y axis we have Price supposedly when the price rises the quantity demanded goes to zero and when it falls it goes to infinite. That being said how the hell is the graph parallel? The way I see it the price is the same regardless of the quantity demanded So i... | [
"By parallel, you mean horizontal, right? Because I think I have the answer to that.",
"Elasticity is a measure of consumers' willingness to substitute a particular good at a particular price. For example, appendectomy is an inelastic good, because there really aren't very many substitutes (there are only two I c... | [
"This is the correct answer. ",
"I did a masters in economics. Keep it up - it's really interesting the more in depth you get (as with any subject). I'd recommend doing some courses that are more practical in nature though, otherwise you may end up finding the actual application of the subject rather hard. "
] | [
"What do you mean by parallel? Parallel to what?",
"One thing that might cause some confusion is the way economists decided to label their axis. Regular scientists plot functions f(x), with x on the x-axis and f(x) on the y-axis. In human terms, the quantity you have control over is on the x, the quantity it affe... |
[
"Hypothetically, how is AI going to help in curing cancer?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"If you disagree with this decision, please send a ",
"message to the moderators."
] | [
"Sure it is, but I want to see if this post will gain some traction and insights from knowledgeable people. It is quite an interesting topic, isn't it?"
] | [
"Our rules are in place to maintain the quality of the subreddit. You can try ",
"/r/AskScienceDiscussion",
", our sister subreddit which is dedicated to more open ended and speculative questions."
] |
[
"I recently learned that scientiists use zircon crystals to date rocks and, with them, the Earth. How do we know that the zircons weren't created elsewhere in material that then combined to form the Earth?"
] | [
false
] | Here's a link to one example: | [
"Well - sometimes they are, and in some instances that fact is the main story the rock can tell. All Zircon-based geochronology studies must begin with a morphological assessment of the material: how many populations are there, do they look fresh, are they corroded, fractured, is their geometry coherent with the se... | [
"Perhaps he is - it still wouldn't change the answer: if that was the case, those would show up as recycled/corroded xenocrysts with ages greater than 4.5 Ga, either processed through a magmatic or a sedimentary pathway. Of course for that to happen, they'd have to survive the Hadean, not likely, but perhaps not im... | [
"I believe the OP was asking if zircons could have formed prior to the formation of the earth and then incorporated into the earth during accretion."
] |
[
"Can a baby contract a venereal disease as it is leaving its being born?"
] | [
false
] | [deleted] | [
"Emergency physician here:\nYes, absolutely. It's a Big Deal too; the baby can become very sick. Here's a short note from the CDC: \n",
"http://www.cdc.gov/std/pregnancy/STDFact-Pregnancy.htm"
] | [
"Yes.. Not only Virus, but bacteria like Strep B are a huge problem as well."
] | [
"Chlamydia trachomatis and syphilis also come immediately to mind. As part of routine care, women are checked for Strep B before giving birth and are treated prior to parturition. "
] |
[
"If telomere length is a primary factor in aging and cell division stops when telomeres run out, wouldn't we see a shorter average lifespan among monozygotic twins than among the general population (or among non-monozygotic twins) due to the \"extra\" division before each zygote begins to develop?"
] | [
false
] | Clearly the effect would be minimal compared to a lifetime of cell divisions, but with so many people out there surely the difference would approach statistical significance. | [
"All vertebrates posses the genes for an enzyme known as telomerase, which has the ability to add nucleotides to the ends of chromosomes to prevent chromosomal shortening. Embryonic stem cells actively express telomerase, so that one extra division would likely have been compensated for by addition of extra nucleo... | [
"Just gonna add my sticker of approval here. Well answered, sir."
] | [
"an interesting side note is that the lack of telomerase acts as a defense against cancer in that it causes senescence to occur. Without senescence our somatic cells would accumulate error through unending division and this would cause cancers of various types. In short, when it comes to telomeres, you're damned ... |
[
"If an object has x joules of energy, does that mean that it can only do x joules of work on other objects?"
] | [
false
] | [deleted] | [
"In theory, yes. But this answer is hardly practical in the real world. The laws of thermodynamics tells us that we can't create or destroy energy/matter but not all of the energy coming out of object x is converted to one form of energy. For example, a ball that bounces off of the floor will not return to a height... | [
"If and only if the transfer of energy is perfect, which rarely exists, there are too many other factors to avoid; gravity, friction, etc. So, with joules (converted to force) and displacement of said item the work is being done upon, it would be fully transferred. See law of conservation of energy/matter. "
] | [
"What do you mean by \"has energy\"? "
] |
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