title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"What does general relativity have to do with the fate of the universe?"
] | [
false
] | null | [
"Cosmology is a branch of general relativity.",
"The concept of spacetime doesn't even exist in Newtonian gravity. The universe is once and forever Euclidean in Newtonian gravity."
] | [
"Ok, then why do you need the concept of spacetime to consider the fate of the universe? It seems like old-fashioned 3-d space and gravity would be sufficient."
] | [
"Because it's not correct. "
] |
[
"What will airlines do when fossil fuels run out?"
] | [
false
] | "My grandfather rode a camel. My father drove a car. I fly my jet. My grandson will ride a camel." - Old Saudi saying Baring an unprecedented and totally unforeseen technological advancement, energy in a post-fossil fuel world will be in the form of electricity (generated by nuclear power, solar, wind, etc.) or biofuels, from crops. Electric cars and buses work fine, but I can't imagine a commercial airplane being powered by electricity. For starters, the batteries would be too heavy. So, are aviation-grade biofuels possible? Is it feasible/possible to have a jet engine capable of running on 100% biofuel? Will we return to the days of the 1950's or 60's, when an air trip cost a month or two of salary and rail (coal) or bus (will be expensive too) or ocean liner (coal) may be the transport of choice? | [
"So, are aviation-grade biofuels possible? Is it feasible/possible to have a jet engine capable of running on 100% biofuel?",
"Absolutely. It's a huge focus in engineering R&D by all the major aircraft/engine manufacturers. ",
"You can read about it here.",
" There have been many commercial flights that used ... | [
"... no."
] | [
"... no."
] |
[
"How do we know what kind of eyesight an animal has?"
] | [
false
] | null | [
"If you're asking how we can tell how far an eye can see, that's just a simple lens problem from physics you measure it out and get the answer. ",
"If you're asking how we know that for instance a dog is colorblind, you can open up the eye and see how many rods vs cones are there since a dog has none of the cones... | [
"/u/zardif",
" explained mammals well, so I'll speak about non mammals. They tested how much jellyfish could see by painting a plastic rod different colours and seeing what rods the jellyfish would swim around and which rods it would swim in to (in different light, florecent paint, etc). "
] | [
"I was going to outline this, but couldn't say it any better, so I'll just add on how the horse shoe crab has been used a lot in explaining how vision works in creatures with less complex eyes than mammals.",
"http://www.ncbi.nlm.nih.gov/m/pubmed/19578331/",
" "
] |
[
"How big of a threat are the ancient bacteria in the arctic due to the melting of ice?"
] | [
false
] | null | [
"The question you're asking is exactly why they seem dangerous at all -- because we don't know to what degree they would affect us.",
"A lot of the issues involving virulence are attributed to the host's ability to respond to an alien strain. Therefore, if we are not trained in recognizing symptoms, treating symp... | [
"I’m a bit late — but that may not work either. Penicillin is good against certain types of infectious bacteria (mostly gram-positive types), but not effective against viruses, due to the mechanism of action that penicillin uses. There’s also the issue of antibiotic-resistant bacterial strains popping up too, which... | [
"This is what I figured. It hasn't been long enough to really find out. Thank you!"
] |
[
"How does your body produce antibodies to fight bacteria to which your body was never previously exposed to?"
] | [
false
] | null | [
"A B cell is a specific type of white blood cell, whose most important job is to make antibodies. An antibody is just a protein. All antibodies have a similar overall shape, but they vary at a particular spot on the protein, which is where the antibody binds to whatever it binds to. One cell will make zillions o... | [
"I don't like the term \"proto-antibody\", especially as a synonym for \"B cell\"."
] | [
"There are components of the recombination called recombination-activating genes (RAGs). Multiple RAGs combine to the DNA and depending where they attach will determine the variable region of the antibody. These RAGs basically create hairpin loops to \"splice\" parts of the germline to create the mRNA that will act... |
[
"Is there a reason we prefer instruments to start flat when tuning by ear?"
] | [
false
] | When I've talked to musicians about tuning by ear, they often say that it is easier to hear the pitch differences and tune accordingly if it is going from flat -> in-tune, as opposed to sharp -> in-tune. For instance, when tuning a guitar, often musicians will make the string they want to tune wildly flat and then bring it up to tune as opposed to making it sharp. Is there a known reason our ears would favor this transition more than a sharp-> in-tune transition? | [
"I'd say because it's less likely to slip back out of tune when you're finished. When going from sharp to flat, the string drags on the nut a bit and the small amount of string between the nut and machine head is unnecessarily slack."
] | [
"Musician here. no research done on this but from experience in learning about music/theory is that its just more \"comfortable\" and usual to go from \"down\" to \"up\" yanno?",
"its like counting. you usually count 1-2-3-4-5 intead of 5-4-3-2-1.",
"or if you're studying intervals, more often than not, they be... | [
"Right! I'm a musician too and I've always found it more comfortable, but I was not sure as to why besides just being used to it. Someone I talked to who works in auditory perception says it may have to do with how the ear recognizes the different parts of a sound as the waves come in, but she wasn't too sure."
] |
[
"How does CERN/LHC deal with soil movement?"
] | [
false
] | I was watching a video on the LHC and this question popped into my mind that I couldn't find an answer to online. Which is how the LHC in Geneva accounts for soil movement, expanding soils, and things like that, given that it's such a massive structure? Wouldn't it eventually throw their measurements off? I know they need a remarkable amount of precision to electromagnetically shoot particle beams into one another. | [
"There is also the central LHC monitoring system:",
"https://op-webtools.web.cern.ch/vistar/vistars.php",
"https://op-webtools.web.cern.ch/vistar/vistars.php?usr=LHC3",
"Now offline, too. Will be back early 2021."
] | [
"There is also the central LHC monitoring system:",
"https://op-webtools.web.cern.ch/vistar/vistars.php",
"https://op-webtools.web.cern.ch/vistar/vistars.php?usr=LHC3",
"Now offline, too. Will be back early 2021."
] | [
"Not at the LHC, but I have worked with scientists at Argonne National Lab's ",
"Advanced Photon Source",
" lab, which runs an electron beam at 99.999% the speed of light around a multi-KM diameter circle.",
"They were noticing disturbances in the electron beam - it was not traveling in the center of its desi... |
[
"Why do mutations occur in the first place?"
] | [
false
] | If you plug 2+2 into a calculator 1 million times, it will give you '4' every time. Why is DNA any different? | [
"If you plug 2+2 into a calculator 1 million times, it will give you '4' every time.",
"Is not absolutely true. The logic error rate is determined by the signal to noise ratio. All things above absolute zero have thermal noise and this leads to a calculation of the error rate. ",
"Bit error rate",
"."
] | [
"There are several ways a mutation in DNA can arise. Some types of errors are due to the fact that the proteins and enzymes that replicate DNA and other nuclear material are not infallible. DNA polymerase along with the regulatory processes which follow during replication have a fidelity of about 1 error in 10 bil... | [
"I actually bet if you had someone run that experiment with a person, you'd get something besides 4 before you got to a million."
] |
[
"Why do magnets only attract ferrous objects?"
] | [
false
] | Are there magnets that attract or repel things which are not ferrous? A magnet, say for ceramics or for silver? If not, why not? | [
"It should be mentioned that levitation of a frog is through ",
", whereas the attraction of materials to magnets is through either ",
" or ",
". In the frog case, the water molecules align to make a magnetic field ",
" that of the applied field, so you get a repulsion. For iron attracting a material, the e... | [
"There is no special magnet for non-ferrous materials. There is only one kind of magnetism.",
"In order to be affected by a static magnetic field, an object needs to have a magnetic moment (i.e., N and S poles). When a ferromagnetic material is placed in a magnetic field, it develops these poles. We say that ... | [
"I was talking about the magnetic field itself, not the response of a material to it. I agree that there many possible responses, but there is only one stimulus. I think that is what OP was asking about. He asked whether there might be \"A magnet, say for ceramics or for silver?\""
] |
[
"I randomly generated 30 numbers and added up 5 at random. Is there a non-trial and error way to figure out which 5 numbers I added? Is this an example of a P vs. NP problem?"
] | [
false
] | [deleted] | [
"One general technique which can save you a lot of time in these sorts of problems corresponds to the maze-solving notion \"instead of searching from the start to find the end, try searching from both the start and the end at once until you meet somewhere in the middle\".",
"For your problem, this would mean maki... | [
"If we know it's five numbers, the brute force solution is O (n",
" ). If wet don't know how many numbers, this is subset-sum, which is known to be NP-complete. I think. "
] | [
"Here's one way to do it in Python. (The algorithm here is Θ(n",
" log n) rather than Θ(n",
"), but the sorting operations can be optimised with some care.)",
"from itertools import combinations\n\ndef find_quintuple(input_list,N):\n triples = sorted(combinations(input_list, 3), key=sum)\n doubles = sor... |
[
"What is nowadays real world application of Reed-Muller codes?"
] | [
false
] | null | [
"Oddly specific. ",
"Reed-Muller codes",
", for those wondering, are a type of error correction code. Error correction codes being a code that adds redundancy to data to ensure that... errors can be corrected. For example, consider sending a 0 for 0 and a 1 for 1. If there is an error in this scheme (e.g., a 0 ... | [
"Whoaa thanks man, really helpful. You even give the references... ",
"I'm working on some paper about reed muller, but well all i ever heard is that reed muller codes had been used in voyager 2 or something mission. I ",
" that's a long long time ago... for now BCH has done the job better involving binary corr... | [
"Well good luck. It is surprising that you are taking a class where you are learning about error correction without being given real world applications. In some ways, error correction as the implementation side of information theory.",
"Error correction codes though are actually necessary for all practical forms ... |
[
"Are there any tenable and/or mainstream critiques to the many-worlds interpretation and the \"multiverse\"?"
] | [
false
] | Or are these interpretations of fairly accepted? What are some alternative points of view? These theories seem so odd to me, and it seems there would be other points of view on the topic that perhaps don't get as much attention, or perhaps are still in their infancy. | [
"Okay. First let me say the very first and most important thing. Science tells us what to expect when we measure something. Quantum mechanics and the associated scientific theories work ",
" well in this scientific regard. The moment we ask what happens between measurements, we leave science for the world of phil... | [
"TL, DR: The interpretations of quantum mechanics are philosophical, and are intended to provide a mental model of what's happening. They are not theories, make no predictions, and any discussion on them is a matter of opinion, not science."
] | [
"Everything there is, kittenboobies."
] |
[
"Why does my mucus become green or yellow when I have an infection?"
] | [
false
] | It's common knowledge that when your mucus turns colors, you have some kind of infection. What is it about the infection or our body that makes this happen? | [
"When a part of the body becomes infected it produces signals to alert the immune system to the developing problem. Cells and other immune components follow these signals by a process called chemotaxis to home in on the affected area. In the case of colds, white blood cells called neutrophils are amongst the first ... | [
"Thanks for the detailed explanation!"
] | [
"So, it is appropriate to assume: The more potent the infection, the more green the mucus will be; while if the infection is less potent, the mucus will be more of yellow colour?"
] |
[
"What is the escape velocity of our galaxy, perpendicular to the disk?"
] | [
false
] | [deleted] | [
"The escape velocity for our region of the galaxy was estimated in 2013 by the ",
"Radial Velocity Experiment",
" (a.k.a. RAVE Survey) as being about 537 km/s. To put that in perspective, the speed of Voyager I relative to the Sun is about 17 km/s.",
"If we really wanted to escape the galaxy, attempting to d... | [
"That's really interesting... I suppose there would be more stars available to do a gravity assist as well, though there'd probably be enough to do it in the vertical plane anyway. Though at those speeds I imagine the margin for error gets smaller and smaller...",
"Hard to think of a practical reason to want to... | [
"That calculation applies when you're orbiting outside a spherically symmetrical object. The galaxy isn't spherically symmetrical, and we're orbiting within it, so our escape velocity is affected not only by mass towards the center, but also mass that's further out from the center than we are. The distribution of... |
[
"How do computers accurately perform calculations which involve irrational numbers such as Pi and e, if these numbers have infinite digits?"
] | [
false
] | null | [
"Computers typically only use an approximation for irrational constants like pi and e. And for any other non-integer values.",
"The commonly used \"double precision floating point\" type has an accuracy of 15-17 significant decimal digits. That means that numbers such as pi and e, which have 1 digit before the pe... | [
"This is not true. While floating point arithmetic is often used, plenty of systems use fixed precision or infinite precision math. There are also plenty of systems that use bit lengths for numbers that are neither 32 nor 64 bits."
] | [
"Yes.",
"Because in a calculation that involves multiple variables, the accuracy of the outcome most strongly depends on the accuracy of the least accurate of those. Suppose you want to calculate the length of a circular orbit to the level of accuracy where you're limited by the standard floating point representa... |
[
"If two different species have similar genome sizes, is it likely they contain the same number of genes?"
] | [
false
] | [deleted] | [
"Genome size is the number of base pairs in the entire DNA sequence of the species. Most of that DNA is non-coding, meaning not part of genes. So a larger genome could just mean more non-coding DNA, and the same number of genes."
] | [
"First off it is not so easy to define gene. That aside genes vary in the number of base pair. ",
"This page",
" shows the wide range found in humans. Going across species (families, etc.) make it even worse. The alleles (variations) of a particular gene in humans are reasonably similar in size but that can cha... | [
"Genes and DNA are very interesting and we are still only scratching the surface of their capabilities. I remember about 6 years ago in highschool biology I was taught that a good portion of human DNA was ",
" DNA. I remember blurting out, \"No! That's not possible!\" The teacher explained that someday I may disp... |
[
"How do we get clocks (digital & analog) to 'know' when a second has passed?"
] | [
false
] | [deleted] | [
"Through very different ways. ",
"Analog clocks (is that the name for them? I'm unsure, but I'm talking about clocks with pendulums) know time by their pendulums. How long it takes a pendulum to swing is not dependent on the size of the swing, ",
"only on the length of the bar",
". Thus, even as the pendulum ... | [
"I think analogue refers to the display being hands instead of numbers, the mechanism is probably called mechanical.",
"Just wanted to add that not all mechanical (clockwork?) clocks use pendulums, they can also use balance wheels which are much cooler and I imagine much more common in smaller clocks (including w... | [
"To specify; Analogue refers to something continuous(like a sun watch), and digital to something in pieces or quantitative(hourglass, with individual grains of sand). Cool video btw. "
] |
[
"Where/How Is Physics Codified?"
] | [
false
] | Is there any straightforward and reliable way for a layman to keep up with what the latest findings are in cosmology, particle physics, etc.? Since I started following a few months ago, I've learned that much of what I thought I "knew" about physics is now known to be false, and that discoveries in the last 10-15 years have led to important new conclusions. I would guess that real physicists keep up by reading around in academic journals, going to conferences, corresponding with colleagues, etc. For a nonprofessional like myself, I have neither the time nor the academic grounding to do those things, not to mention the budget to subscribe to the journals. I've also learned on reddit that much of what is written about science in popular journals directed at layman is pseudoscience, shoddy journalism, and in some cases "not even wrong." Alas, what should be the ideal avenue for we laypeople fails the reliability test. I've learned more here in the last several months than I had in the previous few years, so currently my best option seems to be keeping tuned in to the excellent contributions by the scientists here. Yet something a bit more programmatic and structured would be very welcome. As an example, is the latest accepted version of the Standard Model codified in one place anywhere--and is there a version of this that is understandable by a nonprofessional? Any suggestions? TL;DR - What's the best way for a layman to stay current in physics? | [
"Science journalism is a decent place to ",
" Think of it like a wiki article (just worse sometimes). Try to find if the article is referring to a peer-reviewed journal article. See if you can find that article, maybe check arXiv for a pre-print copy of it. Be careful about arXiv in general, because it isn't peer... | [
"But be weary of things in the \"General Physics\" section.",
"Another thing I'd recommend is just reading the abstracts (or even the titles) of Physical Review Letters. They should be free, and written for a wider audience to understand, and you'll get a sense of what's being done even if you don't know the deta... | [
"Thanks. I hadn't heard of arXiv before... after checking it out just now, I'm pretty sure I'll be spending a lot of time there."
] |
[
"Why is it that whenever I use some mouth wash, my tongue burns when I place it on the bottom of my mouth?"
] | [
false
] | null | [
"My tongue tends to burn when I place it on the top of my mouth. Usually if i press a bit harder, it hurts a bit more."
] | [
"Mouth wash is typically fifteen percent alcohol... That's why. "
] | [
"The one I am using is 0% Alcohol, no joke!"
] |
[
"Is there a logical explanation as to why we put open containers of baking soda in refrigerators? If yes, what does it do and how?"
] | [
false
] | null | [
"Baking soda (NaHCO3) or sodium bicarbonate is a basic salt, so if the odours that your food is giving off (known as volatile organic molecules) are acidic, they will then react with the base and form a sodium salt. Salts are much less volatile and will not have as strong of an odour."
] | [
"I missed a point, it will also absorb basic organic molecules because sodium bicarbonate is also acidic (being both a base and an acid is called ",
"amphoterism",
"). It acts as a ",
"buffer",
" and can absorb both basic and acidic ",
"volatile organic compounds",
" emitted by your food and drinks. [E... | [
"you can hit the edit button if you want to fix your first post : )",
"also foul smells tend to be amines aka nitrogen containing compounds. for example putrescine and cadaverine. these types of amine compounds are produced by decay organic matter that is slowly chemically breaking down (usually due to bacteria)... |
[
"When you pull a hair, does the bulb come out with the shaft? If so, how does it grow back?"
] | [
false
] | null | [
"Sometimes when I pull out a hair, it has a thin transparent layer around the bottom bit. What is that?"
] | [
"Why, then, after so many years of plucking my uni-brow does it insist on growing back. I would think I'd have damaged at least a few of those suckers."
] | [
"You will have, but there are a lot of follicles. Plenty of women are still drawing their eyebrows on because they overplucked in the 70s. "
] |
[
"Does heavier propeller mean more thrust?"
] | [
false
] | In both aviation and maritime. If you think about it, only the shape and the RPM of the propeller must affect the airflow/waterflow, so logically you would try to make the propeller as light as possible, but especially ship propellers are made quite heavy sometimes weighing tens of tons, while making it from a lighter material would save fuel. Aircraft propellers seem much lighter than the watercraft propellers, probably due to air having much less resistance. But how do you calculate the ideal propeller weight and density of the material? | [
"The weight of the propeller and its density don't effect the thrust that it is capable of putting out. Its shape and RPM (as you noted) are the direct factors that determine its output thrust.",
"Now the density of the material combined with its shape will give you the weight of the propeller, so you could so th... | [
"In maritime, I don't know how much weight and density of the prop matters. What matters is the pitch of the propeller. Being able to control the pitch allows you to move fwd or back as well as control the amount of water going through the screw. ",
"I'm sure density is related to this, I just don't know how othe... | [
"Strength and stiffness is also important, as you don't want your propeller blades flexing or yielding under load. So they have to be made of a stiff enough material and built thick enough that they can withstand the stresses involved. Such designs would have the side effect of being heavier."
] |
[
"How do we know that any of the laws of physics are constant?"
] | [
false
] | Obviously the laws of physics are more or less constant in our day to day lives, Newtonian laws have held up nicely, but this is a relatively small portion of the universe. I recently chanced upon article which describes about how there may be variation in alpha, which describes electromagnetic forces. This lead me to wonder, since all of our observations are limited to such a small section of space how could we differentiate observations due to our environment from scientific law? What leads us to believe that gravity, or the passage of time or planks constant aren't "distorted" in our local space similarly to how light is refracted when moving between a liquid and a gas? | [
"Our observations aren't limited to a small section of space. We can see things very, very far away.",
"And what we see when we look at very distant things amounts to the best evidence we have of the universality of the laws of physics: the universe is ",
" and ",
" What that means is that wherever we look in... | [
"My point about local observations was that pretty much all of our scientific observations have been conducted within a limited range.",
"If you define \"limited range\" as some thirty-odd billion light-years, then yes. In an infinite universe, a sixty-billion-light-year sphere is ",
" But the underlying point ... | [
"That's a good point. I can definitely appreciate that the dispersal of matter throughout the universe is a good case for constants. My point about local observations was that pretty much all of our scientific observations have been conducted within a limited range. If for whatever reason, redshift or observed radi... |
[
"why do objects bend space/time?"
] | [
false
] | I was recently watching a documentary on gravity and started to wonder how and why matter bends/warps space and why that causes gravity. also EITMLI6 | [
"We don't know, and we probably won't ever know. \"Why\" is a very tricky question, and it can't usually be answered scientifically. We can measure ",
" something happens, and we can come up with predictive models of ",
" will happen, but to say ",
" something happens requires going beyond that. We can say, s... | [
"Here's a simple thought experiment that should give you a little intuition for why mass bends space.",
"Imagine you're in an elevator. You stand still, jump up and down, whatever. Are you on earth? Past experience says \"yes,\" but here's ",
" possibility. What if, instead of an elevator in the Empire State Bu... | [
"thank you! I have been struggling with this concept for a while now, this is so helpful."
] |
[
"What color is the sun?[astronomy]"
] | [
false
] | So basically if we were able to fly to our sun and be a safe enough distance away, think moon from earth scale, what features would we see and what color would it be? | [
"This color",
". Above the atmosphere, the sun is white with a blue-green tint as a result of its peak wavelengths. Through our atmosphere, the sun's peak wavelengths are greener. However, the sun is still considered white in both cases because its emission strikes every single visible wavelength fairly evenly. \... | [
"Thanks so much! I've always been curious as to what we would see. "
] | [
"No. So what's happening here is they are putting a large filter over the star. Now because red light waves travel further then any other light wave they get through the filter. "
] |
[
"Does vitamin C really improve connective tissue health?"
] | [
false
] | Many coaches and "fitness experts" suggest suppplementing vitamin c for joints health/recovery, but i couldnt really find any good research about it, is there any scientifical proof about it? | [
"Collagen is synthesized in your body as an inactive precursor called procollagen, and to make the final product the body needs the compound called vitamin C as a cofactor. Cofactor means it is a molecule necessary for certain chemical reactions to take place, but we can't make this molecule ourselves and need it f... | [
"From what I know of biochemistry (2nd year med student), excess vitamin C would simply be excreted either through the urine or through faeces. Our bodies don't really store vitamin C in any way. Vitamin C helps enzymes, proteins that make chemical reactions happen. Compare this to trucks that transport cargo; if y... | [
"Vitamin C is a vital nutrient, but deficiencies (e.g. scurvy) are extremely rare in modern life. As such, supplementation is generally considered unnecessary. ",
"Later in life, nobel prize winner Linus Pauling came to wrongly believe Vitamin C was a cure for everything- and the myth is still out there.",
"For... |
[
"When an animal becomes extremely endangered, how do they reproduce without inbreeding?"
] | [
false
] | null | [
"They dont. This leads to an extreme lack of biodiversity and an increase in diseases and deformation. We see this with dogs, and breeding them. There are so few pure bred dogs, that many pure bred dogs ha e deformities and diseases. I know a dog with diabetes."
] | [
"They do reproduce with inbreeding and this will cause their genetic diversity to be greatly diminished. A lack of genetic diversity can be very damaging to a population. A good example of this is cheetahs. Their population was decimated a few thousand years ago causing a massive \"genetic bottleneck.\" Their popul... | [
"They inbreed, it's the only option for them. An interesting example of this is with the wolf population on Isle Royale, an island in Lake Superior. The wolf population has dwindled down to 2 or 3 over the years and so the wolves are horribly inbred. The few wolves left are pretty sickly and deformed. "
] |
[
"Why does tilting a mug reduce the foam head when pouring a beer?"
] | [
false
] | null | [
"If you don't tilt the glass and pour the beer directly toward the bottom of the glass, the beer travels a longer distance, splashes at the bottom, and continues to mix with beer that is poured later. This agitates the beer a lot, adding air bubbles, and ultimately more foam. Tilting the glass reduces the distance ... | [
"So most of this is accurate, but not all of it. I don't mean to sound pedantic, but this is ",
"/r/askscience",
"This agitates the beer a lot, adding air bubbles, and ultimately more foam.",
"The key is agitation. \"Adding air bubbles\" imples that it has something to do with mixing with air - this is not th... | [
"Thanks! Great answer!"
] |
[
"Energy and matter are the same stuff. Can two quanta of energy occupy the same point in space?"
] | [
false
] | [deleted] | [
"(not on panel)Firstly there is no particle called 'energy' :) energy is just one of the conserved quantities. (Hmm treated differently in thermal physics, though it seems, should recheck that)",
"Presumably the energy is where the particle is. And wavefunctions(and corresponding probabilities) of particles can r... | [
"I'm just going to upvote you instead of making a long winded post, because you capture most of the answer here.",
"A lot of this question depends on how you define \"in the same space.\" If you mean \"what is the probability that I will find ",
" A and B at this location\" then that's the probability of them ... | [
"Trying to be handwavy enough to not flood with math and yet mathy enough to not be pure handwaving.",
"The statistics of the particles basically comes in QFT from the behavior of the quantum operators which add or subtract particles of a given species and a given momentum from a state they act on. Multiparticle... |
[
"Why haven't we been able to develop a HIV vaccine yet?"
] | [
false
] | Why do we have vaccines for viruses such as smallpox and the common cold, but yet haven't been able to develop a vaccine for HIV yet? | [
"Because the virus is constantly mutating. The envelope protein only has a few conserved regions while the rest - particularly the big loops that come off the surface - are highly variable. Plus, the surface is covered with glycans that shield the surface making it difficult for the immune system to interact with p... | [
"Actually there ",
" a really promising treatment currently in development which blocks the interaction of the virus with the human protein which allows it to export virus particles from the human cell. Since the human protein does not mutate, this part of the virus cannot mutate to avoid the interaction and so r... | [
"If the envelope protein is mutating, how come it keeps the parts that stick to the immune system cells? Couldn't a vaccine or serum be made to interact with those parts? "
] |
[
"How does a dog detect low insulin levels?"
] | [
false
] | Me and my roommate thought it might have something to do with a change in the composition of your smell or breath but we are not entirely sure | [
"I can smell when a diabetic is getting hyperglycemic. It's just a specific scent. ",
"I am sure it's the same for a dog. ",
"I read about an older lady that could smell when a person was getting Parkinson's disease. ",
"Once you recognize a scent you just know when you smell it again. And scent is chemical i... | [
"I don't know precisely what the dogs are picking up on, but diabetic people's breath have a distinct smell that humans can notice, too.",
"It's causes by raised levels of ketones in the blood, which comes from the increased breakdown of fat when sugar is unavailable, either due to starvation or diabetes. Intense... | [
"It's quite unlikely they smell insuline levels, they probably smell sugar. If your blood glucose goes up your metabolism changes, cells start burning more sugar, your kidneys start flushing out sugar, probably your skin too. So there are a bunch of potential chemical clues there."
] |
[
"I’m a chemist so I should know the answer to this question but I don’t. Why is Technicium a synthetic radioactive while the two elements above it on the periodic table (Manganese and Rhenium) are naturally occurring elements?"
] | [
false
] | null | [
"There's no single reason. Out of the ~3000 known nuclides (at least 7000 are predicted to exist), only a lucky few (less than 300) are stable.",
"No element is \"entitled\" to have ",
" stable isotopes (except maybe hydrogen, barring proton decay). Although it turns out that most elements up to and including l... | [
"Now that's a wondrous thought... is there such a thing as a \"Nuclear\" Periodic Table rather than the \"Electronic\" Periodic Table we know and love?",
"After googling a bit, it seems that there is! Or, at least one group has attempted to construct one: ",
"https://link.springer.com/article/10.1007/s10698-020... | [
"Couldn't explain this any better.",
"I'd just like to add that for the purposes of nuclear physics / chemistry, comparing an element to the rest of its group on the periodic table (like OP does in the title, comparing Tc to Mn and Re) is misleading.",
"The overall structure of the periodic table comes from the... |
[
"Shellfish is such a broad term but if you are allergic to it you can't have any at all. So what specifically in shellfish are people allergic to?"
] | [
false
] | Shellfish is such a broad term but if you are allergic to it you can't have any at all. So what specifically in shellfish are people allergic to? | [
"The main thing in shellfish that causes an allergic reaction in humans is a muscle protein called ",
"tropomyosin",
". It's not necessarily true that if you're allergic to one kind of seafood you're allergic to all of it (or even all shellfish). ",
"Here's a brief summary",
" of the results of a few studie... | [
"You're welcome! I'm glad I could help restore your \"faith\" in reddit haha"
] | [
"Awesome, I was afraid I wouldn't get a response. I love reddit for things like this! Thanks so much"
] |
[
"Is storing solar energy under the form of pressure a thing?"
] | [
false
] | I was brainstorming ways to store solar energy or do something useful with it while its available. The most practical things seemed air conditioning and cryptocurrency mining. But why not use a compressor/water pump to fill up some tanks, in combination with a valve and turbine, to use that pressure for energy at a later time? | [
"the energy density of compressed gas is terrible, on either a volume or weight basis.",
"there are much more compact ways to store energy, such at in a chemical reaction (Batteries) or gravitational field (dam)",
"https://en.m.wikipedia.org/wiki/Energy_density",
"from the table there, 300 bar (full had cylin... | [
"Nevertheless it was still tried:",
"Huntorf plant in Germany (290 MW) diabatic. 580 MWh energy, 42% efficiency.[23]",
"McIntosh plant in Alabama, USA (110 MW) diabatic. 2,860 MWh energy, 54% efficiency.[23]"
] | [
"Kind of a similar concept, ",
"pumped-storage hydroelectricity",
" is a good way to store excess energy from intermittent sources like solar or wind. The idea is pretty simple, you use excess energy to pump water up a storage container. When you close it off, energy is stored as gravitational potential energy.... |
[
"In DNA tests, how do geneticists determine what a person is ethnically?"
] | [
false
] | [deleted] | [
"How is it that people vary in size, shapes, colors?",
"There are things known as SNPs (Single nucleotide polymorphisms) which really just are common mutations in the population that cause variation within the population. ",
"tracing origins",
"The distribution of SNPs is used for DNA fingerprinting. SNPs are... | [
"This is a thorny issue. There isn't a genetic test that can determine what your race/ethnicity is, although attempts at identifying ",
"gene clusters",
" that correlate to self-reported race and ethnicity have been made. In general each SNP we identify has only a weak correlation if any to what race people ide... | [
"Yep! They send you a kit, you swab your cheek and send it back",
"Environment will also play a role. For example, access to good nutrition tends to increase height. I will try to pick some links for articles on Central American ancestry. My memory of Mexico and the Dominican Republic is that ancestry markers run... |
[
"technical math question on filtered white noise"
] | [
false
] | Hello. This is a very technical question. I hope this is ok. Consider a random process F(t) defined by: F(t) = (f * W) (t) where: f is some filter which we know W is a white noise process '*' is the convolution product Is it possible to calculate the random process F(t + tau) | F(t) = x ? (F(t + tau) knowing the value the random process actually took when it was at time t) Or some sort of covariance leaving from value x ? Feel free to just give me pointers to the theorems with which you can answer this question without too much developpement. I will be able to finish the work. Thank you | [
"For a sufficiently narrow bandpass filter, sort of. The amplitude and phase will still be random, but you'll have obviously reduced the variance in frequency to the point where it's fairly predictable.",
"What do you mean by covariance leaving from value x?"
] | [
"No, it is not possible to predict the outcome of stochastic processes given current conditions. You can sometimes estimate within an interval where the value should lie. ",
"Source"
] | [
"No, you cannot perfectly calculate the value of a random process at an unobserved time. You should be able to say something about its distribution in this case, which would allow you to predict a value for the process. Kalman filtering may be helpful here."
] |
[
"Can I change a recoring of my voice so it sounds as it does to me when I'm speaking?"
] | [
false
] | [deleted] | [
"Technically this is absolutely possible!\nYou would basically want to \"EQ\" the recording until it matches what you hear in your own head (using EQ, compression, etc.). This would of course be totally subjective, since you're the only one who really knows how you sound in your own head. ",
"This would be compli... | [
"Technically yes. However the microphone will not pick up the vibration in the exact same way that your eardrum will, so you would still end up with tonal differences in the recording. But with the right microphone and the right placement you could probably get close. Would take a lot of trial and error though. "
] | [
"Technically yes. However the microphone will not pick up the vibration in the exact same way that your eardrum will, so you would still end up with tonal differences in the recording. But with the right microphone and the right placement you could probably get close. Would take a lot of trial and error though. "
] |
[
"When Earth was this warm (and warmer) in the distant past, how did it affect plant and animal life?"
] | [
false
] | I continue to hear that it's been X-hundred-thousand years since the last time Earth was this warm. , for example, show that the Earth was about as warm as today ~125k years ago, ~240k years ago, ~325k years ago, and ~410k years ago, and I'm guessing some of you could provide longer-term graphs with older and warmer periods. I also continue to hear that today's temperature variation is causing mass extinctions, which makes me wonder how these past temperature local-maximums affected life. Do we know? What theories and evidence do we have? | [
"There is a recent thread that has been posted about this here: ",
"http://www.reddit.com/r/askscience/comments/1dc95m/greenhouse_gas_levels_highest_in_3_million_years/",
"You asked about warmth levels, and because greenhouse gas levels have been positively associated with warmer temperatures, I would like to r... | [
"Thanks! That's what made me think to ask this, and I didn't want to hijack the thread since that was focused on the causes and I was looking for effects, but looks like a lot of relevant info has been added since I last looked!"
] | [
"50 million years ago, during the Eocene, the earth was so warm that the Arctic had a climate similar to the southeastern US. It is thought that the deciduous habit of larches, bald-cypresses, and dawn redwoods originated as an adaptation to the darkness of the polar winter."
] |
[
"How the heck does smart shade makeup (Almay) work?"
] | [
false
] | Almay makes a foundation called "smart shade" that is supposed to change to match your skin tone. It comes out of the tube looking white with little black specks in it, but as you rub it into your skin, it turns to a fleshy colour. What kind of sorcery is this? Help me ! | [
"This actually turned out to be a very interesting question, and I'm glad you asked it (I think I might even write/draw it up on my blog). For all the rest of the men who doesn't know what RainbootRobot is talking about, she's referring to ",
"this",
", and The Internet seems to suggest it actually [works] (wi... | [
"Wow, thank you! The comic is especially helpful. Oh marketing, the fine art of lying and getting away with it."
] | [
"Good morning - my pleasure. I had a second look at their marketing stuff, and I think they worked quite hard to make sure it's legal ",
". So it says things like, ",
"The lightweight formula starts out white and adjusts to right\" ",
"in which \"right\" technically could be anything. The most adjustable t... |
[
"Do dock leaves have a non-placebo effect on stings?"
] | [
false
] | I've searched around a bit and haven't found a satisfying answer, so thought I'd ask here. The idea that dock leaves grow near stinging nettles because 'nature provides a cure' or 'where there's a need, evolution will provide' always seemed like baloney to me. But I'd prefer to actually know rather than having an equally-invalid gut reaction. So is there any evidence for rubbing a dock leaf on a sting providing any kind of chemical relief or soothing beyond what we would expect from the placebo effect? | [
"A quick google and I came up with ",
"http://skeptics.stackexchange.com/questions/3031/does-rubbing-a-dock-leaf-on-a-sting-from-a-stinging-nettle-help-to-reduce-pain",
" which reports that Dock contains an antihistamine which would easily explain why they work.",
"Another quick google and I can see other rep... | [
"Well, yeah, but those two are pretty much the same thing, wouldn't you say?"
] | [
"I always understood the reasoning to be that nettle stings were acidic and dock leaves were alkaline (or vice versa). Putting the latter on the former therefore neutralizes it. But a little googling suggests that they are both acidic (or at least most species in the same genus of dock leaves are, and I find no rep... |
[
"How does water form bridge? (GIF in decription)"
] | [
false
] | Water bridge formed by electric current but how does this phenomenon occur? | [
"Short answer: \"the scientific community agrees that surface polarization at the water surface when a high tangent electrical field is applied is responsible for the extraordinary stability of the system.\"\n",
"Source",
" (Wikipedia)",
"Long answer",
" (interesting material!)"
] | [
"I imagine that it is energetically more favourable for the system to allow the current to flow through the water bridge than for the water to stay put. ",
"In the paper cited by ",
"/u/hyseptik",
", they used a potential difference of 15 kV with a current of 0.5 A. That's a power of 7.5 kW. Now if 10 mL of w... | [
"Do you think it might be possible to use this property on a large scale for some sort of transportation device? I'm thinking something like the chutes from Bionicle, if you're of that era..."
] |
[
"How does food get carried to every single cell in your body?"
] | [
false
] | I'm mainly thinking about how blood vessels can't possibly connect to every single cell in your body. If so, how do remote cells get their food from? (Also just to confirm, the chemical reaction that turns glucose into energy happens inside a cell right? | [
"Capillaries do a good job of communicating with tissues throughout your body, but don't come into contact with every cell. A couple of things help out with this. One is ",
"interstitial fluid",
" which bathes cells and contains glucose. Also, some cells communicate with each other through various ports includi... | [
"This answer here. Beat me to typing it."
] | [
"This isn't exactly my field, but I'm relatively sure that most cells are located within a few cell thicknesses of a ",
"capillary",
"."
] |
[
"Can human or non-human cultural behaviour be coded into genes?"
] | [
false
] | J.T. Bonner in "The Evolution of Culture in Animals" defines culture as "the transfer of information by behavioral means, most particularly by the process of teaching and learning. It is used in a sense that contrasts with the transmission of genetic information passed by the direct inheritance of genes from one generation to the next." What I am wondering is that if there is any behavioral trait in humans or non-human animals, which falls under this definition as "culture", but has been passed on from generation to generation under such a long time that it has transformed from a mere cultural behavior into one which is genetically coded? For example, could the migrational pattern of birds have at some point started off as a behavioral pattern where one individual/group of individuals randomly migrated and this information was "culturally" (in Bonner's sense) passed on to the next generation until it eventually became genetically coded? | [
"Cultural behavior, strictly speaking is not genetic. However, if it provides an evolutionary advantage, then genes that favor this culture will become more prevalent. I don't see that it couldn't turn those cultural behaviors into instinctual behaviors, but I don't know of an example of that.",
"For instance, C... | [
"Human Universals is a popular book which studies the universality of human behaviours, based on Donald Brown's research. Certain behaviours (e.g. smiling) were found to have a universal meaning (there were 67 'universals' in total).; though you can probably find an exception to the universals if you look hard eno... | [
"Execellent question. I downvoted everyone because I don't think anyone tried to answer your question. OP is not asking about the definition of culture, nor the genetic basis of human behavior. Instead I think she/he is asking a much more awesome question of could the line between the two be blurred over time. Star... |
[
"Can you catch 2 strains of covid at the same time?"
] | [
false
] | null | [
"Yes. There was a RadioLab podcast 2 weeks ago (",
"COVID Crystal Ball",
") about how an immunocompromised patient had multiple variants and how they could actually track which ones were winning the battle to be the most virulent (not sure if that is the best way to describe). Essentially is was a small micro... | [
"Damn. Thats crazy."
] | [
"maths shows that one contaminated with the covid generates more copies than required to statistically create a mutation. \nbut this new variant will eventually not be able to reproduce again (cell host contamination)"
] |
[
"Could Earth have become tidally locked around the Sun, like the Moon is around Earth?"
] | [
false
] | The implications for life on Earth are fascinating if this were to happen. | [
"It's not a past thing, it's a future thing. Over long enough time, this is the preferred configuration. The amount of time this would take for the Earth would be much longer than the expected lifetime of the sun. The time for Earth to get locked to the moon is faster, but still over billions and billions of years.... | [
"The amount of time this would take for the Earth would be much longer than the expected lifetime of the sun. ",
"Because of the moon, the Earth can never be tidally locked to the sun. Since the moon is so much closer than the sun, its tidal effects are greater and the earth will become tidally locked to the moon... | [
"Nope! The only possible way for that to happen is for the moon (or whatever the least massive body in the 3-body system is) to be in the L1 Lagrange point, but at that point you can hardly call it a satellite of the earth. The L1 Lagrange point is itself unstable, anyway, but in principle you could have the moon i... |
[
"What is the origin of Aboriginal Australians?"
] | [
false
] | How did homosapiens come to Australia? Were they the same people from Africa? I'm under the impression that homosapiens came from Africa, then went to Europe; it seems hard to accept that they made it all the way to Australia around the same time. I'm reading the prehistory of Australia on wikipedia right now, but it is creating more questions than answers for me. | [
"Try ",
"History of Indigenous Australians",
" and discuss the questions which the articles bring up for you in addition to your main interest."
] | [
"you accidentally put two brackets and broke your link. As a sidenote the ",
"image that illustrates this article",
" is one of the contributions I made to wikipedia I'm most proud of... "
] | [
"old site with good info"
] |
[
"Why is nuclear decay logarithmic?"
] | [
false
] | null | [
"The probability that a particular radioactive atom will decay in any given amount of time does not itself vary with time (so far as we have observed). This means that as a sample of atoms is decaying away, the number that decay in any time span is simply proportional to the number of atoms that are left.",
"Mat... | [
"You mean exponential?",
"Basically it's because if any nucleus has a probability to decay in a given time, if you have two nuclei the probability of a decay is twice as high (could be either one in that time period that goes), and if you have a million it's a million times as high. So you can say that the rate a... | [
"The mathematical term for this function is technically \"exponential,\" not \"logarithmic.\"",
"Imagine you have a billion people rolling a hundred-sided die, all in sync with each other. When you roll a 42, you're killed. Roughly 1%, or 10 million, will lose on their first roll. Roughly 1% of those remaining (a... |
[
"Why does water in my toilet rise and fall on a really windy day?"
] | [
false
] | Aren't most municipal sewer and water systems completely underground? If that's the case, why would high wind have any affect on the water in my toilet? | [
"From ",
"Wikipedia",
":",
"The venting system, or plumbing vents, consists of pipes leading from waste pipes to the outdoors, usually through the roof. Vents provide a means to release sewer gases outside instead of inside the house. Vents also admit oxygen to the waste system to allow aerobic sewage digesti... | [
"Take a look at this toilet cutaway illustration",
" The water sitting in your toilet acts much like the trap farther downstream from it. When the water in the bowl is lower, the parcel of water is free to move up or down the piping behind the bowl without spilling any additional water down the pipe.",
"On a wi... | [
"Thanks folks. You can likely tell me and basic plumbing have never met."
] |
[
"The Mars rover found that Martian soil is composed of about 2% water. How significant is this number? What about compared to the Sahara? What else should we expect after finding this water on Mars?"
] | [
false
] | [deleted] | [
"It means ",
"much-less-than",
" (seriously)."
] | [
"So most rocks on Earth contain water in them a granite will include a few percent water (3-5 is a good range) and you don't see anyone trying to get water from a stone... So compared to Earth this is not super wet but it is a lot wetter than the moon where it's really dry. ",
"TL/DR: This is a marginally excitin... | [
"Moon rocks are <<1% water"
] |
[
"Does cracking your windows actually help them from being blown out during a hurricane?"
] | [
false
] | If keep a few of my windows cracked during hurricane Sandy will it actually help keep them from shattering? I've thought about this and am really torn between pressure differences acting as force across the area of the closed window vs the wind gust's pressure against the window will make that difference in pressure negligible... | [
"Not scientific at all, but somewhat relevant personal experience.",
"I was in a tornado 4 or 5 years ago where water was seeping in sealed emergency exits. I know the pressure is worse in a tornado, but I'm guessing that if you had windows cracked you would have massive amounts of water in your house. Board up y... | [
"The best protection you should do is simply cover them in plywood. Sudden large pressure changes are more a tornado thing than with hurricanes."
] | [
"TL;DR: It's best to board up your windows if you're expecting a hurricane.",
"Mythbusters actually tested something similar (Season 7 Episode 16) with regards to the pressure differential in a house during a Category 2 hurricane. While it should be noted that they weren't testing the windows in particular, said... |
[
"Why doesn't ice sink in water like most solids, and how rare is that?"
] | [
false
] | [deleted] | [
"When most things freeze, the reduced activity of the particles reduces their ability to escape the forces that are trying to pull them together and this is why most things shrink and become more dense as they are cooled.",
"As I understand it, water is an exception to this because of the structure of the molecul... | [
"No, logic! Go away!",
"I was expecting a pun thread from top to bottom. "
] | [
"Most solids don't sink if they're in the right shape.",
"Just a reminder to phrasing your question carefully. The question is answered by somebody else so I'll just add one thing: it's extremely rare for the solid form of a substance to be less dense than its liquid form."
] |
[
"Male orgasms are much more intense if you masturbate and stop right before ejaculating for a few times before actually doing it. Why does this method work?"
] | [
false
] | [deleted] | [
"Most nerves use something called cascades (proteins use it too but proteins use hormones instead of cations). The cascade is basically when something small causes large changes and an increasing avalanche effect/chain reaction (this is why you can't stop an orgasm once you hit the vinegar strokes). If the levels h... | [
"Also works for women,."
] | [
"Not that I know what I'm talking about:",
"Why is it that if one is interrupted after a few approaches towards the crest of cascade (I suspect Reddit will produce a \"Cascading\" meme now) is the cascade stumbling and rather poor? ",
"If the hormonal load behind the levee has built up so high, what is it that ... |
[
"Where do all the \"breakthrough\" medicines we hear about go?"
] | [
false
] | So often you hear about super intriguing medical breakthroughs that science has discovered. Many things seem like they would completely eliminate a heath problem or an illness, but then years later you still have not seen the results. What happens to all these miracle drugs and surgeries we hear about (like the one or two a week that pop up on reddits front page)? And maybe more specifically the things we see working on lab mice? | [
"It has to do with drug development and treatment testing. As you progress through phases, treatments run into snags. What worked great in an animal model loses steam in a human trial. After the open ended human trial, maybe it doesn't separate from standard treatments in randomised trial. Perhaps a side effect is... | [
"Another part of this is that the follow-ups are most often not covered by the popular media - they simply report the discovery. A follow-up look at scientific/medical journals after the development/testing phase will help identify which of these are actually \"breakthrough\" medicines. ",
"For example, a new ",... | [
"Here is a comment I wrote",
" a while back for ",
"/r/explainlikeimfive",
".",
"The short answer is this: is the stage of research reported? It's likely not, or you don't pay too much attention to that. Many of these are very, very early stages of research, and later trials eliminate the vast majority of c... |
[
"Is bullying evolutionarily related to the idea of humans forming groups (tribes), then ridding themselves of those seen as weak?"
] | [
false
] | null | [
"Is bullying evolutionary related to ... ridding themselves of those seen as weak?",
"Not directly, no.",
"Here's an informative article on ",
"The Origins of Bullying",
", which examines bullying across human cultures and across species.",
"One of the core factors in bullying appears to be establishing d... | [
"Maybe I was too narrow in my line of questions, because the article you posted (excellent, thank you!) seems to agree with my basic idea. ",
"Bullying, it seems is part of our normal behavioral repertoire, it is part of the human condition.",
"...",
"Humans have taken an ancient behavior that used to provide... | [
"I wasn't implying merely infanticide",
"No, but a similar principle applies, i.e. the relatively infrequent cases of bullying that result in killing, and the non-lethal outcome of the majority of bullying cases indicate that the killing of unfit members is not the evolutionary \"purpose\" of bullying.",
"the d... |
[
"Why don't I ever experience destructive interference of sound waves from two speakers?"
] | [
false
] | I would think that, if I had two speakers on my desk, playing the same sound, the speakers would have a small chance to play the sound back just right so that they interfere and the sound is made quieter. I would assume that the speakers are not playing the sound exactly synchronized all the time, so I would expect to hear (if not often, but at least every now and then) the sound canceling out and being quieter. However, I have never experienced this, so why? | [
"Maybe because you don't typically listen pure tones. For complex waves, like songs, or almost any real world audio, there are many frequencies present. And so if some frequencies are occasionally attenuated, you may not really notice.",
"Try it with pure tones. λ = v / f, so for sound typically v = 343 m/s. Fo... | [
"You have two ears. The likelyhood that both would fall in a null point, and that the null point would be stable at those two points (reflections and stuff mess with that), is very low as the wavelength drops. The whole shebang is massively complicated by the rich spectral content of music and the complexity of the... | [
"You can test it thoroughly by setting up a pair of speakers, and then moving around the room a little bit and seeing how the sound gets louder and quieter depending on where you are in the room, provided both speakers are playing the same pure tone."
] |
[
"Does language/culture affect our emotions ? Example : If the English language did not accommodate complex emotional words like \" indignation \" and such , would we still recognize them the way we do now ?"
] | [
false
] | [deleted] | [
"This is an ancient and complex debate in linguistics, really the best thing is to start at the right ",
"wikipedia article",
" and explore for yourself from there. "
] | [
"There is little scientific research which suggests that any idea contained in vocabulary cannot be transfered from one language to the next(though it must be said that grammatical differences do effect understanding, though in a slightly different manner, I will attempt to discuss this later). when europe was expa... | [
"Here's an interesting article from NYTimes last year, quite thorough too."
] |
[
"If a bullet were traveling at 100mph"
] | [
false
] | This is all hypothetical, but, if a bullet were traveling at 100mph ad you were traveling at 99 mph away from the bullet and you have some distance between you, say 50ft. Would the bullet hurt you when it finally came in contact with you? Or would it just poke you and be slowed down by the speed you are going? I know this seems stupid but its just something me and my friends came up with last night. | [
"This is the fundamental concept behind on-orbit spacecraft rendezvous",
"Dissenters PWNED. Awesome."
] | [
"I agree. Questions like this aren't stupid and often spawn really amazing answers and side topics. "
] | [
"I agree. Questions like this aren't stupid and often spawn really amazing answers and side topics. "
] |
[
"Tsunamis and submarines?"
] | [
false
] | [deleted] | [
"same thing as the boat. The wave will pass with little notice. Tsunamis aren't really anything until the energy starts to mash up against land masses. Out in the open ocean there is nothing like that. "
] | [
"I haven't downvoted you, and I am not disagreeing with your physics. The similarity in perception is between a tsunami hitting a beach and a rogue wave hitting a ship: a single event that makes an otherwise normal ocean dangerous and remarkable."
] | [
"can't really agree with you that a rogue wave is similar to a tsunami though. ",
"a tsunami is a deep water, long period wave while a rogue wave is typically a confluence of ocean swells which combine to be more substantial than the other swells. "
] |
[
"How does a modern smartphone antenna work? Why don't we anymore need the long antennas from the 90's?"
] | [
false
] | null | [
"A few things happened. First, signal processing got a LOT cheaper, which means that you can work with an extremely weak signal using inexpensive IC's (something that only NASA used to do for interstellar space probes is done routinely on your phone today.) Second, new signaling formats were adopted that take adv... | [
"Edit: unfortunately, I think it's also true that phone today suck a bit more than they did in the 90s in terms of reception.",
"Interestingly, this is not at all related to the antenna, but rather population density. Network bandwidth is actually channel speed times channel capacity. Channel capacity is limited ... | [
"Modern phones use sheet antennas. There's a sheet of copper in your smartphone for your wifi antenna and a separate sheet for your mobile data antenna.",
"As for why, modern phones are expected to send/receive a lot more data, and as a general rule (with a large number of complications and exceptions) you can ac... |
[
"If electric currents make magnetic fields, and electrons in atoms are constantly moving, why isn't everything magnetic?"
] | [
false
] | null | [
"Every single atom has a magnetic moment. In materials however the direction of this magnetic moment is (generally) randomly distributed, resulting in no net magnetic moment of the material.",
"Magnetic materials can realign their atoms giving a uniform magnetic moment in the same direction."
] | [
"Yes. By raising the temperature of the magnet to the ",
"Curie temperature",
". You could also do it by waiting a very very long time."
] | [
"Ferromagnetic is like your fridge magnets, ",
"https://en.wikipedia.org/wiki/Ferromagnetism",
"The intrinsic magnetism of the metal atoms are \"lined up\" to form a large coherent magnetic field."
] |
[
"Why do electrical transformers give off a blue color when they arc/explode?"
] | [
false
] | The video from ESPN last night showing the transformer explosion and subsequent power outage at Candlestick Park got me thinking. I asked everyone at work, and no one has a good answer... any help? | [
"Blue is the color that our atmosphere glows when ionized; it's mostly nitrogen. Other gasses will glow different colors, which is why neon signs glow red."
] | [
"Ah. Safe to assume ozone is formed during this ionization?",
"Thanks for the answer, I appreciate it. "
] | [
"Sure. Oxygen glows pink."
] |
[
"Why does cancer occur so often now?"
] | [
false
] | It seems like twenty years ago I rarely heard of it, and the further back in history the least likely-hood people died from it. I know technology plays a role, but why does it happen so much these days. Also, what killed so many people before the presence of cancer was so common? | [
"Cancer is a disease of old age. Cancer is formed when a cell in the body undergoes a series of ~4-7 mutations, successively breaking cellular machinery designed to keep the cells from replicating out of control. Since each mutation even has a very small chance of happening, the chance of these mutations accumula... | [
"Lots of times, juvenile cancer can be traced to a congenital mutation in an oncogene. ",
"Retinoblastoma",
" is the classic example. But it sounds like you are well aware of this.",
"You can glean a little more insight if you look at ",
" cancers are more prevalent in young people. Across all ages, the ... | [
"Less common or less detected? Medicine has a come a long way in a very short time."
] |
[
"How does testosterone decrease fat body mass?"
] | [
false
] | I was looking at a and I couldn't really pick apart WHY the fat is lost. | [
"According to ",
"some",
" ",
"reading",
" I've done, testosterone does not significantly decrease the total fat mass of your body. Rather, it increases ",
" in the form of lean muscle tissue. This can, in and of itself, decrease total fat content simply because ",
"muscle cells are metabolically active... | [
"Your statement was",
"I have never heard of that. I have, however, heard that test increases muscle gain, so your body fat percentage goes down as you mentioned. I suspect, this is the info OP has gotten slightly wrong.",
"My statement was",
"According to some reading I've done, testosterone does not signifi... | [
"That clarifies your comments a bit more, thanks. And I apologize if I offended you. The wording of your statement made it appear as though you were offering some sort of correction in the first line \"I have never heard of that.\" although I can see where the disconnect in interpretations may have stemmed from."
] |
[
"What is the physics behind the wave-like motion of this bridge before it collapses? Also, what were the engineering mistakes?"
] | [
false
] | [x-posted to ] | [
"False!",
"It's a widely spread myth, but the collapse was ",
" caused by resonance. In order to create resonance, it would need to receive a periodic force, as you described it. But the wind was approximately constant. The collapse was apparently caused by ",
"aeroelastic flutter",
" which, I have to admit... | [
"False!",
"It's a widely spread myth, but the collapse was ",
" caused by resonance. In order to create resonance, it would need to receive a periodic force, as you described it. But the wind was approximately constant. The collapse was apparently caused by ",
"aeroelastic flutter",
" which, I have to admit... | [
"As ",
"/u/TarMil",
" pointed out, it was due to aeroelastic flutter. Basically, the further the bridge had been pushed by the wind, the easier it was for the wind to push it. This lead to larger and larger vibrations."
] |
[
"How could that 16-year old have possibly survived stowing away in the wheel-well of a that 35,000 ft altitude California to Hawaii flight? 5 hours of no pressurization, no heat, low oxygen; how did he not die?"
] | [
false
] | null | [
"Perhaps the landing gear area is mostly airtight, keeping the air inside pressurized to some degree. Another idea is that the kid simply passed out shortly after takeoff and re-awoke after landing--he stayed in a state of half-hypoxia during the flight and got enough oxygen because he was asleep/low bodily requir... | [
"Perhaps the landing gear area is mostly airtight, keeping the air inside pressurized to some degree. Another idea is that the kid simply passed out shortly after takeoff and re-awoke after landing--he stayed in a state of half-hypoxia during the flight and got enough oxygen because he was asleep/low bodily requir... | [
"The BBC article",
" explains that he was, indeed, unconscious during most of the flight."
] |
[
"Thin strings of smoke near atomic explosion. What is it?"
] | [
false
] | Hey I was watching a video about atomic bombs and I noticed that next to a few of these atomic bomb explosions there were about 10 thin strings of smoke. Like right in the beginning of this video: Are these strings put there to watch how the blast wave moves or is there an other reason? Thanks | [
"The smoke pillars are in roughly equal distance to each other. That means they are probably placed there on purpose and not an incidental by-product. My guess is that they are used to determine a) the pressure wave and/or b) the wind direction to estimate the fallout (area,density)."
] | [
"Henkersjunge is correct: Taken from: ",
"http://www.atomcentral.com/atomic-smoke-trails.aspx",
"In order to study the velocity of the shockwave front, rocket trails were located perpendicular to the line of site and the shockwave was photographed as it passed in front of these trails. The progress of the shock... | [
"They are smoke trails left by rockets that are set off just before (a second or two before) the explosion. The point is as you surmise, to see the blast wave move through the air. ",
"In ",
"this video",
", even though the feed is grainy, you can distinctly see them being launched right as the countdown near... |
[
"Assuming no water or insect damage, at what age will the kiln-dried pine wood making up my roof trusses become brittle and unable to support itself?"
] | [
false
] | I don't really know what happens to wood that is dried and protected from moisture, that is what I am asking I guess. How long before wood is unusable as wood just because of time alone? Imagine this: we build a concrete waterproof room that is temp and humidity controlled for all eternity. We put a pine kiln-dried 2x6 across the middle of the room, half-way up. The room is sealed forever. How long before the board breaks and falls? | [
"This Buddhist temple in Japan has wood from about 1500 years ago, \n",
"http://en.wikipedia.org/wiki/H%C5%8Dry%C5%AB-ji",
"It is thought to be one of the world's oldest wood buildings. So, at least 1500 years.",
"If the wood is kept in a controlled humidity and temperature and pest free, I can't imagine wha... | [
"Wood is mostly cellulose fiber and Lignin, right? They're both stable biopolymers, and I expect they'll last essentially forever in the absence of chemical attack. ",
"Wood will tend to get a lot stiffer over the first couple of years as it loses water, but that slows down asymptotically. There are wooden articl... | [
"Haha oldest post I've ever replied to. No idea what link got me here. This comment was very thought-provoking. I started reading your wood comment thinking you were being a smart ass, but noticed it was in posted to science so I figured I'd give the comments a chance.",
"This comment made me think of somethin... |
[
"Do you think Synthetic Humans should be given human rights?"
] | [
false
] | null | [
"Speculative questions are better suited for ",
"/r/asksciencediscussion",
"."
] | [
"Ok, thanks"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScienceDiscussion",
"Please see our ",
"guidelines.",
"If you disagree with this decision, please send a message to the moderators."
] |
[
"Are we--and all multicellular life--just giant biological synergies between our cells?"
] | [
false
] | I mean, there isn't really anything that makes our cells any more special than bacteria, as far as I'm aware. Is it possible that complex life just originated from a few cells suddenly finding out that it is easier to reproduce when attached to different cells? Edit: not even sure that synergy is the exact phrase I'm looking for, just couldn't be bothered to search for the right one. | [
"I mean, there isn't really anything that makes our cells any more special than bacteria",
"Our cells actually differ a LOT from bacterial cells in important ways.",
"Our cells are able to communicate with each other through a variety of specific and functionally distinct pathways that do not exist in bacteria ... | [
"No problem!",
"The cellular-to-multicellular transition is pretty poorly understood, so it's reasonable to be kind of confused about it. Especially if you're just trying to approach it from a conceptual/evolutionary perspective, and unfortunately the organisms we have at the base of Metazoa are all pretty weird ... | [
"Multicellularity evolved multiple times independently (e.g. animals, plants, and fungi). And there's even some cases where previously multicellular organisms became unicellular again (bakers yeast). There are a lot of advantages to communal living, from there cells start to specialize because that increases effici... |
[
"Why is escape velocity so high?"
] | [
false
] | Why is the escape velocity for earth 11.2 km/s? Can someone explain why it needs to be such a high speed? Why can't a vehicle just travel at a steady 1 km/h until is out of reach of the planet's gravity? | [
"It can, it would just need to be thrusting the whole time. Escape velocity is the speed you need to escape without adding any more energy - just coasting. That is why escape velocity depends on altitude - the higher up you are, the less speed you need to go the rest of the way."
] | [
"Earth's radius is 6,371 km. The benefits of launching from a few extra kilometers higher up are far outweighted by the logistical effort required to transport rocket parts up to the mountains. ",
"What does help though, is launching from near the equator, due to Earth's spin. Launching over the sea also prevent... | [
"It could. But you’d need to continually apply that acceleration. ",
"Once you reach escape velocity you no longer need to apply any force. You can essentially hit neutral and coast the rest of the way and the earth can’t stop you. "
] |
[
"How is the right amino acid brought to ribosomes?"
] | [
false
] | So what I know is that the mRNA is brought to the ribosome with a code for an amino acid. I also know that the tRNA with a matching codon and correct amino acid are brought to the ribosome for assembly. But how is the right amino known? Does the ribosome read the mRNA and call for a tRNA or do the tRNA keep trying to fit the codon in the ribosome till it fits then goes and brings the amino acid. Thanks i have a test on this is a couple of hours. | [
"But how is the right amino known?",
"Put simply, it doesn't 'know'. All the amino acids are attached to tRNAs and they all diffuse around until they meet a ribosome that requires that particular one, as determined by the codon of the mRNA. It can't \"call for it\" it just waits for it. "
] | [
"All the amino acids are attached to tRNAs",
"This is the key part.",
"While I do not know the exact mechanism, hopefully someone can expand on the following I do know: There are specific enzymes, at least one for reach amino acid, that bind the correct amino acid to the correct tRNA. It also has to do with the... | [
"This animation",
" shows the process of translation nice and simply and ",
"this one",
" shows DNA > protein in more detail. ",
"They're not included in those videos, but ",
"Aminoacyl tRNA synthetases",
" are the enzymes that transfer amino acids onto the tRNA. "
] |
[
"How did different species evolve to have different numbers of chromosomes?"
] | [
false
] | Even different species of apes have different numbers of chromosomes. Since they are presumably descended from a common ancestor at some point, doesn't this mean that there have been multiple instances of breeding between two animals with different numbers of chromosomes that was successful? My understanding is that if the chromosomes don't match up, the offspring will be sterile, mentally handicapped, or both. | [
"All great apes apart from man have 24 pairs of chromosomes. There is therefore a hypothesis that the common ancestor of all great apes had 24 pairs of chromosomes and that the fusion of two of the ancestor's chromosomes created chromosome 2 in humans. The evidence for this hypothesis is very strong.",
"The Evide... | [
"\"a creationist that question\"",
"FTFY"
] | [
"Chromosomes can separate or fuse into new chromosomes, such as in the case of our own ",
"chromosome 2",
". "
] |
[
"In view of recent reports of thylacines possibly being caught on tape in Southern Victoria, what kind of follow up would normally be carried out to authenticate such potential sightings."
] | [
false
] | And any relevant comments on the hypothetical possibility that thylacines might perhaps not yet be extinct, what would come next should their actual existance be confirmed, and other related subjects are welcome of course. see: | [
"Nothing, really. ",
"According to ",
"Tasmania Parks & Wildlife",
", there have been hundreds of reported sightings of thylacines since the last known individual died in a zoo in the 30s, but no proof beyond unclear videos and hearsay. This new video isn't even the first thylacine \"sighting\" ",
"this mon... | [
"To be considered conclusive you'd ideally need a dead or live animal, although DNA evidence ",
" be considered conclusive if it was substantial enough (eg. if droppings of thylacines started showing up). I don't really think any amount of video evidence could truly be considered conclusive, especially how easy ... | [
"I'd add a simple anatomy observation. In the longer video the length of the rear feet clearly rules out it being a thylacine. The thylacine has a very short rear foot. ",
"google images",
"In the video at this point",
" (1:30) you can clearly see that this animal has exceptionally long feet, very much like a... |
[
"Is there a way to speed up the process of radioactive decay?"
] | [
false
] | I'm curious if there is any method that we have to speed up the rate of decay in radioactive materials? For example, a radioactive material that normally has a half life of 1000 years and making that half life shorter. | [
"You can make it happen on demand by hitting it with a moderately zippy neutron or other high-energy particle. If you use the high-energy particles from fission to force other fissions then you have invented the concept of a nuclear reactor - or a bomb if you did it all at once.",
"Arguably smashing the nucleus i... | [
"If we knew of such a way, then all of our efforts at Radio Carbon Dating to learn about the past would have to be called into question. The fact is, the most accurate clocks in the world use radioactive decay as a standard by which to measure time itself. I would be very surprised to hear if anybody anywhere had... | [
"Correct, save for the atomic clock bit. A cesium clock uses the vibration of electrons to count time, they are not dependent on radioactivity. Decay through the weak force is statistical in nature, so you can't use that to measure fine time intervals. Over long time scales, that statistical average is pretty darn ... |
[
"Is it possible to take dead wood, and soak it with calcium mixture to make it slowly become bone as wood decays and bone slowly grows into the shape of the wood?"
] | [
false
] | Is this possible? Even if not, i'd like to learn the mechanics of those systems, so any explanation would be great and well-appreciated | [
"...well what do you know.",
"Popular article: \"Turning wood into bones\" ",
"http://news.bbc.co.uk/2/hi/europe/8446637.stm",
"Journal article: \"From wood to bone: multi-step process to convert wood hierarchical structures into biomimetic hydroxyapatite scaffolds for bone tissue engineering\" ",
"http://p... | [
"Something tells me OP didn't tell us everything..."
] | [
"Can someone explain the chemistry behind this?"
] |
[
"Why is it that there can be water vapor in the air when it's cooler than its boiling point?"
] | [
false
] | When the air is below 100 degrees Celsius, how can there still be gaseous water mixed in? | [
"Because ",
"vapor pressure",
"."
] | [
"It's because water has a finite vapour pressure even below the boiling point.",
"Microscopically, some water molecules in the liquid state shuffling around at the interface just randomly gain enough energy to leave the surface and go into the gas phase."
] | [
"Sorry to reply to such an old thread, but I'm trying to figure this out without asking it as a new post.",
"Could you say that the boiling point of ",
" water is less than 100C (based on the pressure or whatever around it?). ",
"I've been searching for an answer to this that I can understand, and I think the... |
[
"Am I wrong? Should I go back in my textbook or not?"
] | [
false
] | null | [
"There's plenty of tests and experiments that have been done that show significant change in the genetic make up of a population, done both ",
"artificially",
" and ",
"naturally",
". ",
"Those links just scratch the surface on a huge field of research showing that the evidence for evolution is extremely ... | [
"The best synonym for theory in this context is \"framework.\" The framework of evolution.",
"If somebody is deriving the behaviour of particles in a two dimensional universe, are they working on a theory or not?"
] | [
"Yes, it's wrong. Every sound experiment has a null hypothesis and is tested to a certain level of statistical significance. Because you can't prove a positive, you define it as a negative and prove that wrong.",
"If you were trying to breed MRSA in a lab, your null hypothesis would be \"the culture does not gain... |
[
"Theoretically, how small can a microchip be fabricated?"
] | [
false
] | I keep hearing of new CPUs going from 65nm to 45nm. Is there a limit on how small we can make them? | [
"When you hear 45nm or 22nm or 14nm (which is the latest Intel technology, planned to be released sometime in the next two years), they are referring to the gate length of the minimum sized transistor in the chip. The ",
"L in this picture",
"\n refers to this length. In reality, the technology node (say, 14nm)... | [
"There is ",
"talk",
" of single atom transistors.",
"However, the current trend in economics seems to make this unlikely. As ",
"/u/lookatmetype",
" said, it is unlikely large scale silicon fabs will progress beyond 10 nm."
] | [
"I worked in molecular computing research briefly (although we were developing materials for data storage); there is definitely funding for the research side.",
"How viable manufacturing is is a different question; in our research all the theoretically viable target molecules we found were near impossible to synt... |
[
"What happens to black holes at the heat death of the universe?"
] | [
false
] | null | [
"After a very very long time they would radiate away in the form of Hawking radiation."
] | [
"According to what we know about quantum gravity, once the CMB's temperature becomes lower than Hawking radiation's because of cosmic expansion, they would slowly start to lose mass by said radiation, until they eventually evaporate completely. The time for a stellar mass black hole to evaporate would be of the ord... | [
"Does the virtual particles needed for hawking radiation still appear when entropy gets lower?"
] |
[
"Can different species ever evolve into the same one?"
] | [
false
] | For example, if large populations of the were transferred to a habitat where there was only one constant source of food (theoretically), would any two of these species evolve into the same species because of the parallel habitat and way of life? | [
"A quick search of the literature turns up ",
"this example",
" of the three-spined stickleback, a Canadian fish. In this case, two species of fish which were closely related to each other but inhabited different depths of a particular lake combined to form a single population with greater genetic variation.",
... | [
"Adaptations would be the same but it is unlikely that they would be able to successfully mate."
] | [
"Convergent evolution is where separate species evolve into very similar forms. They can't interbreed, but the whole organism, or certain parts, will look nearly the same."
] |
[
"Is radioactive decay temperature-dependent?"
] | [
false
] | Does the rate of radioactive decay for an isotope vary with temperature? For example uranium-235 has a half-life of 703.8 million years, but would cooling to absolute zero (or very close to absolute zero) have a significant influence of the rate of decay? | [
"Typically is not, the nucleus is so much smaller than the atom that it doesn't \"care\" what's happening around it (imagine a marble at the center of one of those giant human hamster balls). There are maybe a few small exceptions. ",
"One could argue that the electron-capture mechanism (sometimes called inverse ... | [
"Low temperature doesn't freeze time... Two stationary things (wrt eachother) experience the same time."
] | [
"I'm having a hard time discerning where I feel this explanation is wrong because all of that is sound thermodynamics.",
"I would like to discuss time dilation further however in the sense that cooling to absolute zero would in essence freeze the atom in perpetuity to an outside observer.",
"Given that, the low... |
[
"Has the change from plastic to paper straws had any quantifiable impact on the environment?"
] | [
false
] | null | [
"Plastic straws and stirrers are ",
"estimated to comprise 1.9% of marine litter",
", a small fraction of the ",
"50% of manufactured plastics which are disposed of after single-use, leading to 150 million tons of annual plastic waste worldwide",
". Marine litter is ",
"eaten by creatures such as the Lysa... | [
"2% is a lot. I always thought it was much less. Gonna focus on my straw choices now!"
] | [
"It bothers me thar I still get a single use plastic topper lid with my paper straw. I don't care about the straw either way, and given the choice I'll just drink like a normal cup without a lid/straw. But it seems... off to be just replacing straws and not lids as well. Though it's probably harder to come up with ... |
[
"is the nuclear fallout from japan going to cause health problems in the USA?"
] | [
false
] | [deleted] | [
"In short, no.",
"http://www.reddit.com/r/askscience/comments/sqdjk/would_the_collapse_of_the_fukushima_reactor/c4g4f3g"
] | [
"There is no \"fallout\". This is more indicative of nuclear explosions. Radioactive exposure-wise, no. Not even close."
] | [
"Thanks for the link! =P"
] |
[
"Why is vision grainy at night or in dark areas?"
] | [
false
] | At night time why does human vision appear grainy? | [
"Because your central vision (where you have color perception) is high resolution (higher density of light-sensing cells) but low-sensitivity (requires more light to detect) whereas your peripheral vision is low resolution and high sensitivity (and so works better in low light than color vision).",
"From an evolu... | [
"That's true but you explained it poorly. The center of your vision falls on the part of the retina called the fovea where a lot of the cones are. The rods are more present outside of the fovea. So at night whenever you look at something, anything you are directly looking at you're going to have a harder time seein... | [
"Also natural night time light is biased towards the blue end of the spectrum because of Rayleigh scattering. Because of this night vision is more reliant on blue cones which are ",
"sparsely populated compared to red or green cones",
"."
] |
[
"Could a black hole ever be harvested?"
] | [
false
] | null | [
"The stuff inside the event horizon could never be brought outside of the event horizon."
] | [
"Qv ",
"Penrose process",
"."
] | [
"With that being said; black holes evaporate via hawking radiation so you could harvest that.",
"Large black holes evaporate much slower then smaller black holes.",
"That being said, my reasoning is that since small black holes would be relatively safe, when I say small I mean artificially small black holes, of... |
[
"When does your body start to break down muscle instead of fat?"
] | [
false
] | yep | [
"There is always a muscle turnover rate. Meaning your body is constantly breaking down and rebuilding new muscle. Its breaking down somewhere around 500 grams of protein a day, give or take a couple hundred grams. Its also synthesizing new muscle every day about the same rate as the breakdown. Now the change in siz... | [
"WRONG!"
] | [
"ok Thanks cause all the bodybuilding stuff I read make it seem like you need to constantly workout and get protein supplements otherwise your body will just randomly start breaking down protein cause it requires the most energy to maintain"
] |
[
"Why don't horses lie down very often? How can they sleep while standing?"
] | [
false
] | I have never seen a horse lie down and in a recent Reddit discussion many people said it is not common for horses to lie down. | [
"Being able to go from sleeping to instantly running is probably a pretty good evolutionary advantage."
] | [
"Horses can sleep standing up because they have a specific ",
"\"stay apparatus\"",
" in their limbs. Basically, it allows horses to transfer the load of the body from muscles (which use energy and are relatively unstable relative to tendons or bone) to connective tissue structures or bone. This eliminates the ... | [
"Thanks! That explains the standing up part but are there any other animals that sleep while standing, or lie down less often?",
"Also is there any evolutionary (or any other kind of) advantage of such behavior?"
] |
[
"Do any animals other than humans like spicy food?"
] | [
false
] | null | [
"Spiciness, caused by the chemical Capsaicin, appears to be an adaptation of plants to prevent mammals from eating their fruit/peppers. Birds, which are immune to Capsaicin, appear to be the intended consumer of these fruits, which is understandible considering they fly and can, thusly, disperse the seeds over a w... | [
"Askscience downvotes anecdotes."
] | [
"Capsaicin is actually also an ",
"analgesic",
" for birds, so not only are they unable to taste the spiciness capsaicin actually is a pain reliever."
] |
[
"From a quantum mechanical standpoint what happens to random physical objects when unobserved?"
] | [
false
] | Let's say I have sealed off my bedroom from any outside interference (no radio waves, etc.). I leave my room and turn off the light so there is absolutely no observation/photon involvment. Every object in my bedroom is has become in the scientific sense of the word, "unobserved." If such a controlled environment could exist what exactly would be going on inside my bedroom? Would the physical objects in the room still exist in the same sense as I think of them existing or would they be taking on an additional form as well as existing in the sense I know? Second part: Let's say I enter the room and turn the light off behind me. No photon bombardment of any sort. Would my mere presence be considered an observation? I guess what I'm wondering is this: Could I somehow experience the dual nature of subatomic particles or is that inherently impossible? | [
"Firstly, it would be impossible to seal yourself of like that at a macroscopic level. You still have thermal blackbody radiation being emitted from everything in your room. As well as thermal and acoustic vibrations being transmitted through the objects and the air.",
"Secondly, observation refers to more than j... | [
"The objects in your room will probably stay the same with 99.99999999% probability.",
"Yes, there is always a slight probability that electrons, protons, and neutrons will appear in locations that are energetically unfavorable, but those probabilities are exceedingly rare. Ground-state electrons won't leave atom... | [
"It's how the math works out. Essentially, it boils down to Planck's constant.",
"If Planck's constant were much, much higher, then we would see quantum effect in the real world.",
"If Planck's constant were much much lower, then we wouldn't experience quantum effects at all."
] |
[
"Is there any significant advantage for computer applications to be in 64-bit compared to being in 32-bit?"
] | [
false
] | null | [
"There are some, although the list is fairly short.",
"Firstly, 64-bit processors provide 64-bit addressing, allowing for access to a ",
" of memory -- vastly more memory than is practical to actually have on a physical machine. Using a flat 64-bit memory model",
" a 64-bit computer can a) store an address p... | [
"True, but the size of the floating point registers does not necessarily match the size of the integer registers. Intel's 32-bit processors and even their 16-bit processors with a math coprocessor could do 64-bit and 80-bit floating point math. "
] | [
"Excellent response, thank you."
] |
[
"What are some issues that quantum field theory and general relativity have that make it so they don’t match?"
] | [
false
] | [deleted] | [
"There are a few issues the two theories have.",
"For one, they predict that different things should happen inside a black hole. Relativity suggests that the curvature of spacetime should be so extreme inside a black hole that all matter will end up in an infinitely dense point, called the singularity. Quantum me... | [
"General relativity is a classical theory which ignores quantum mechanics. Yet it describes gravity being sourced from matter and energy which we know is described by quantum mechanics, so we expect that GR needs to be made quantum mechanical. In particular, since matter can be in some superposition, it doesn't see... | [
"What does this mean tho??",
"Simply put: we have 2 theories that, under known circumstances, agree very well with experiment. In very particular regimes these theories fundamentally disagree with each other and produce wildly different results. ",
"does it mean that one of the theories is wrong??",
"Scientis... |
[
"Why Do Certain Chemicals Cause Different Individuals To Experience Similar Complex Thoughts/Hallucinations? Where Is The Information Coming From?"
] | [
false
] | null | [
"There might be confirmation bias going on here, just because \"many report\" is not necessarily indicative of the expereinces of most users. My own experience with DMT was like a kaleidoscope with no other \"entities\".",
"All brains are wired differently but pretty much all of them use the same chemical schemat... | [
"Schizophrenics provide some interesting insight into the topic, ",
"EASE",
" and ",
"EAWE",
" provide a really thorough list of common experiences and for some it's pretty easy to see how the delusions can come about to rationalize simpler more understandable experiences. For example I knew a schizophrenic... | [
"Schizophrenics provide some interesting insight into the topic, ",
"EASE",
" and ",
"EAWE",
" provide a really thorough list of common experiences and for some it's pretty easy to see how the delusions can come about to rationalize simpler more understandable experiences. For example I knew a schizophrenic... |
[
"What is actually happening when I see a 'shooting star'?"
] | [
false
] | null | [
"Just a clarification: The heat's not really from the drag force, it's mostly from compression forces of the rocks being supersonic."
] | [
"Just a clarification: The heat's not really from the drag force, it's mostly from compression forces of the rocks being supersonic."
] | [
"You are seeing a rock burn up in the atmosphere as it falls down towards the ground. Most rocks will disintegrate into dust as they fall and never actually reach the ground. The rocks are moving up to 50 miles per second, so as it stars to hit the air, the air heats up and burns the rock.",
"Many rocks come from... |
[
"Is it possible to give a planet without an active core a magnetic field?"
] | [
false
] | I'm mostly thinking of Mars, inspired by a top post in this sub about compass use on the planet. I know the reason Mars is barren is it's lack of a protective magnetosphere, but could the planets core be jump started or an artificial field be developed? Obviously both require vast amounts energy but let's pretend such energy is available for said purposes. | [
"I don't really know where the research is now but NASA talked about the feasibility of placing a magnetic field-generating satellite at the Mars-L1 Lagrange Point to shield Mars from the solar winds as seen in the diagram: ",
"https://3c1703fe8d.site.internapcdn.net/newman/csz/news/800/2017/1-nasaproposes.jpg",
... | [
"Wouldn't want to upset the belters though"
] | [
"Wouldn't want to upset the belters though"
] |
[
"Please forgive my ignorance."
] | [
false
] | I'm going to use made up numbers and hope I still make sense. This question has been bugging me for weeks now. If I am on a spaceship traveling for 10 years at 99.9% the speed of light - I will have aged 10 years while someone on earth will have aged 500 years <please remember: made up numbers> So, if I were to get in my spaceship, and travel to a solar system 5 light years away (and back) -- (please exclude acceleration) -- I'd age 10 years, but to anybody back on earth I'd take 500 years. The solar system is 5 light years away (round trip 10) I'm traveling essentially the speed of light there and back. If I'm travelling 99.9% the speed of light why does it take me 500 years to reach my destination? Or alternatively If (travelling 99.9% SOL) it takes 10 years round trip from an Earth-relative position to make the trip - - - -- How quick is the trip for me aboard the spaceship? How fast did I travel? Again, please please excise my complete ignorance. Ignore me if I'm asking a dumb question. Kind regards, DAL82 | [
"Or alternatively If (travelling 99.9% SOL) it takes 10 years round trip from an Earth-relative position to make the trip -- How quick is the trip for me aboard the spaceship?",
"This is correct. If you travelled at near light speed 5 light years and back, on Earth 10 years would have passed. The trip for you wou... | [
"Length contraction would make it appear to be much less than 10 light-years to you."
] | [
"Great, I can visualize that.",
"But what I can't visualize is what MY speed would be. ",
"I'd manage to travel 10 light years in far less than 10 years. ",
"EDIT: Thanks for your quick reply. :)"
] |
[
"At what rate is heat lost in a vacuum."
] | [
false
] | How quickly will an object radiate it's heat in a vacuum and how does this compare to loss of heat in a atmosphere? | [
"5.67 * 10",
" joules of energy every second per square meter of exposed surface times the temperature of the object raised to the fourth power. It is less than in the atmosphere because of the loss of conduction to air."
] | [
"That number assuming a blackbody radiator?"
] | [
"Yes."
] |
[
"How far could Baumgartner travel if he wore a winged suit during free fall."
] | [
false
] | null | [
"You can't just multiply like that because gliding requires air resistance, which was notably absent for a good part of the stratojump."
] | [
"Yes, in a first-order approximation you can.",
"You get less lift (i.e. you fall faster) but you also need less force to move horizontally. Both because of the lower air density. All that changes is the absolute glide speed. You will (once you're up to that) follow roughly the same trajectory as in denser air, j... | [
"Wikipedia says:",
"On 31 July 2003 an Austrian, Felix Baumgartner, jumping from 29,360 ft (9 km), successfully crossed the English Channel in 14 minutes using a wingpack, having covered over 35 km (21.8 mi).",
"That would mean he had a glide ratio of 35/9 = 3.9",
"For his Stratojump the distance would be 39k... |
[
"What deadly viruses could we feasibly eradicate in the future - which ones will probably always be around?"
] | [
false
] | null | [
"Polio has once been wide-spread, now it's limited to two countries and could get eradicated in the near future: ",
"https://en.wikipedia.org/wiki/Poliomyelitis_eradication",
"Not a deadly virus, but dracunculiasis might be close to eradication: ",
"https://en.wikipedia.org/wiki/Eradication_of_dracunculiasis"... | [
"Theoretically speaking, any virus that only infect humans have the potential to be eradicated. Viruses that can also live in animal hosts cannot be eradicated by current technology. Even if you vaccinated the whole human race, any subsequent generations born afterward can still get infected through animals."
] | [
"I think HIV is a candidate for future eradication if medication is made available to all who need it. With treatment, Viral load can be brought down to such low levels that a HIV positive individual could (not should) have unprotected sex and not pass the virus on. ",
"It’s also worth noting that HIV is much les... |
[
"How can I weigh more in the evening than in the morning without eating or drinking?"
] | [
false
] | null | [
"That's got to be scale error. Normally people continuously lose mass due to respiration (because for every O2 you breathe in, CO2 leaves, and there's also some loss if water vapor. Perhaps your scale's readings vary slightly with ambient temperature? "
] | [
"I thought it was scale error also. I also know that my bathroom is 70 degrees plus or minus 1 degree. I check the temperature both times. I also accounted for scale error by weighing in ten times each time and averaging them out. "
] | [
"Mysterious! But it's got to be the scale somehow... I teach physiology, and humans who aren't ingesting or excreting anything always lose weight, detectably, every hour. We even do a lab on it. Unless you're photosynthesizing I don't see how it can be real.",
"It may just be that you've had one of those statisti... |
[
"Why don't trees freeze and fracture? Or do they?"
] | [
false
] | How does a tree stay warm? Or does it? | [
"The short answer is that they can: ",
"http://en.wikipedia.org/wiki/Exploding_tree",
"However, they typically don't for several reasons. First of all, under certain conditions, water can remain liquid at temperatures below what would normally be considered its freezing temperature. This is known as ",
"super... | [
"Vascular system works on capillary action, trees don't have hearts.",
"True.",
"So the water in these vessels are only a few molecules across...",
"False. They're unfathomably wider than that.",
"It's due to a lack of ",
"nucleation sites",
"."
] | [
"Trees can freeze and fracture! In fact, I saw one that had done so in the crazy midwest cold that struck last week. Super cold temperatures can overcome the following three mechanisms I've explained below.",
"Trees and other cold-tolerant plants do a couple neat tricks to avoid having all there cells explode in ... |
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