title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Do noise canceling headphones protect your hearing?"
] | [
false
] | I was on my flight home today and I had a thought: do noise canceling headphones actually make things quieter, like an in-ear monitors with a custom fit mold do? Do noise canceling headphones have this same effect? Or do they just fake your ears into thinking things are actually quieter? | [
"Noise-cancelling headphones use a microphone to detect outside noise and then create another signal to cause destructive interference. While one might think that two sound waves could only trick the ear into making things quieter, interference is actually a property of all waves. When one sound wave is at its cre... | [
"Ear plugs, as non-vacuum matter, can still conduct sound. Even with a perfect plug without a passage of air to conduct sound around the plug, there is still some sound going through it.",
"Therefore, the effect of an earplug and noise-cancelling headphones are different. I'd say it depends on how well some types... | [
"I was wondering if when they emit the opposite wave if that sound still affected your ear in anyway, or if its like the sound disappears. I'll check out the article. "
] |
[
"Do stars have anything like an Atmosphere?"
] | [
false
] | I've always assumed that stars are a swirly twirly ball of gas more like atmosphere than surface. But it occurred to me that the sun might possibly have significantly different layers of density. Is there anything like an atmosphere in regards to stars? | [
"Here",
" is a nice summary of the structure of the sun.\nTo quickly answer your question, the ",
"corona",
" of a star could be considered something akin to an atmosphere."
] | [
"The Sun (and all stars) definitely have an internal structure. See ",
"this",
" page. ",
"This",
" section in the wiki page does an excellent job in explaining the different layers, including it's 'outer' atmosphere."
] | [
"thank you!"
] |
[
"What's that smell coming out of my nose?"
] | [
false
] | I occasionally catch a whiff of a very sharp scent coming out of my nose (I think it originates in my lungs). I've smelt it on the breath of one other dude too, but it's an unmistakeable sharp smell. Is this the smell of one of the products of respiration, or what is it? edit: I don't have halitosis. I brush and scrape my tongue twice and floss once every day | [
"I'm pretty sure carbon dioxide is an odorless gas."
] | [
"Not Safe For Life.",
"Worse than NSFW. Not safe for sanity."
] | [
"Unless you're really sick, it's not from your lungs. Your mouth is filled with a myriad of different kinds of bacteria so it's impossible to answer this (for me). Maybe some other supastar will come along, but I'm reasonably confident of my answer. "
] |
[
"Rotate a 3D lens on a laptop screen and at certain angles it goes opaque. Why does this happen? [GIF provided]"
] | [
false
] | Rotate the lens from a pair of 3D cinema glasses on a screen, and at a specific angle (and the opposite angle) it completely darkens. Gif: I know it's got something to do with , but with only 1 lens, why would this happen? Thanks! | [
"I want to add to the discussion that most 3D glasses aren't simply linear polarization filters, but ",
"quarter wave plates on linear filters",
", essentially making ",
" polarization filters. This means that if you flip your lens over, it won't block the screen light in the same way."
] | [
"LCD screens consists of two polarizing filters with a layer of liquid crystals inbetween. The first filter creates a linearly polarized light source. The layer of crystals either does nothing (if there is no voltage across the pixel), or turns the polarization direction of the light 90 degrees. The second filter i... | [
"Yes I noticed this, if you flip it the other way it seems to have a blue/yellow tint, depending on the angle.",
"pic: ",
"http://imgur.com/a7z1L0a"
] |
[
"How does the annihilation of antimatter and matter upon impact cause both particles to disappear?"
] | [
false
] | [deleted] | [
"In classical approximations, conservation of mass is definitely a thing, and is probably discussed in most introductory physics courses. However, in relativistic or quantum regimes, mass and energy become interchangeable and exchangeable (think Einstein’s famous E=mc",
" ). Conservation of mass is no longer vali... | [
"There is no such law as the law of conservation of mass. It is approximately true for non-relativistic systems. What has to be satisfied is the conservation of energy and momentum, plus other charges. In physics everything that is not forbidden is compulsory :) So, converting two electrons into one photon (a parti... | [
"Trivial, but I believe there should be a plus sign between the two terms in the first equation."
] |
[
"Why does the browser on my smartphone take so much longer to load than the browser on my laptop."
] | [
false
] | I have a powerful smartphone (GS3) and a rather outdated laptop. When I load a webpage (almost any webpage) on my laptop it loads almost instantly, but if I load the same webpage on my phone it takes 3-4 seconds. The thing is- I run my computers internet over 3G! The websites I load on my computer are actually being routed through my phone. At 2.8ghz, my Computer is a lot faster... but browsers are surely not especially memory intensive. I've tried several: Chrome, Firefox, Opera, and they all run a lot more slowly on the phone. Why is this? | [
"The processor in your phone is not nearly as capable as the one in your computer. A browser is a relatively complicated bit of software - it has to take a html input and translate it into a complicated page format, while simultaneously placing and rendering image files, as well as (often) a lot of back-end securit... | [
"Thankyou. This us exactly what I was looking for. ",
"I'd be interested to know why we don't benchmark in flops when buying a computer. "
] | [
"Even FLOPS are not necessarily particularly meaningful in terms of performance. There's a lot of inter-relating factors, not least of which are the software you're interested in running in the first place."
] |
[
"If you were in a swimming pool on the Moon or Mars - Would you float higher, lower or the same?"
] | [
false
] | null | [
"The same. Buoyancy is dependent solely on the relative densities between the objects in question. Thus, you will float in water when you have displaced the same mass of water as you have. Masses and densities are not dependent upon gravity. "
] | [
"This quote, and my explanation are not in conflict. ",
"An object floats when it displaces an equal amount of mass of water that the object has. Since an object and the water is in the same gravitational field, the object and the displaced water will also weigh the same. The weight of the water you displace is e... | [
"The ",
" of the water varies in exactly the same way as does the ",
" of the object (the product of local gravity and mass), so in effect it is displacement of equal masses."
] |
[
"Would ultrasound imaging find surveillance devices in drywall?"
] | [
false
] | If so, what's the cheapest type of device that would be likely to pick up a device, say, the size of a fish hook? Of course, there are better tools for the job, but I want something that's: 1) super cheap (you can rent medical equipment, but security equipment) 2) able to detect devices that have been remotely shut off 3) able to detect devices made of mostly non-metallic components Hiring a PI is an option, but I'm assuming even the best equipment will fail to find deactived devices in a one-pass sweep (that's why there's a monitor mode on the high-end devices). Would something like the Ultrasound Sonicator 710 work, or is that even an imaging device? Update: Just posted some related questions on a private investigator forum, and received this . Oh yeah, my real name isn't Oliver North. | [
"Ultrasound probably wouldn't work for looking past drywall. I'm guessing you would be looking for a device that is in the air behind the drywall and between the wooden frames of the wall? The air gap would destroy your signal. Ultrasound works by reflection of high-frequency sound off of material boundaries/int... | [
"I have no knowledge on these devices, but I would have assumed that an ultrasound was developed to work within a specific set of frequencies - ones that are specifically picked to work well when travelling through human tissue and liquids - and to then reflect off just the right amount.",
"I would be seriously s... | [
"I would have thought that all the goop they use on the thing is there really to ensure that the sound is transmitted through into the body rather than just to make the scanner slide around the body easier. If they didn't need all that stuff, why not just do it througha T-Shirt or whatever without all the need for ... |
[
"How long did the Challenger Astronauts survive?"
] | [
false
] | I worked for a startup once that had an airforce pilot as one of the investors (he came from a wealthy family). He had done extensive training with NASA and was on the short list to go on a shuttle mission. He once told me that in the astronaut training, at one point they play the audio recording from the Challenger command module as it descended to the ocean. Contrary to popular belief, the astronauts were all still alive, and they can be heard on the recording. Supposedly, the ones with the military background remained remarkably calm, while Christa McAuliffe, on the other hand, was understandably freaking out. One astronaut even expresses that his only regret was that he never actually made it into space. When the recording ended, everyone in the room was in tears. Does anyone know whether a) this would even be possible, given the violence of how the Shuttle came apart, and b) whether there is any truth to this? Has anyone else ever heard this? | [
"Wikipedia",
" has about all the info you're likely to get",
"At least some of the astronauts were likely alive and briefly conscious after the breakup, as three of the four Personal Egress Air Packs (PEAPs) on the flight deck were found to have been activated. Investigators found their remaining unused air sup... | [
" ",
"http://www.snopes.com/horrors/gruesome/challenger.asp"
] | [
"And surely the voice recorder onboard was at least as well-designed as aircraft black boxes, which easily survive much higher G impacts than this one, and which have been recovered from the ocean floor.",
"The snopes article (And the original rumour) contains question of a personal recorder, not a Flight Data Re... |
[
"Is the Planck Length the smallest measurable length, or is it the smallest something can be? In the latter case, how is it not theoretically possible to, say, halve this lengths?"
] | [
false
] | null | [
"See the FAQ. The Planck unit system has nothing to do with \"the smallest possible X\"."
] | [
"All I would want to write about this, I've written ",
"here",
"."
] | [
"Thank you "
] |
[
"What is the difference between an electrochemical gradient and an electrical current?"
] | [
false
] | How do they behave differently? Are they under vastly different physical constraints? This question comes from trying to figure out how the action potential works within neurons when it "hops" over the myelin sheaths during saltatory conduction. I forgot to add that this is a cross-post from | [
"They are two separate things. Electric current is simply the flow of charged particles. An electrochemical gradient is a combination of a gradient due to a chemical concentration difference between two concentrations of charged particles (ions) and the electric potential that is induced what you have two different... | [
"The action potential depolarization will propagate down through the cytoplasm of the axon until the next unmyelinated node of Ranvier, where ion channels there regenerate the action potential."
] | [
"So how does the current go over the top of the myelin sheaths which have no ion channels? This discussion came up when talking to an friend who is in electrical engineering. He says that the distance that the current would have to go when hopping over is too far for electrons to travel, since a current needs \"dir... |
[
"How does our brain filter lots of conversations so that we almost always notice when our name is said?"
] | [
false
] | For example, when you're standing in a crowded room with a bunch of conversations, you won't usually notice what other people are saying, but if they mention your name, you tend to hear it. This seems like it would be useful for a number of reasons, but I'd like to know more about how our brain accomplishes this. | [
"What you're asking about is the ",
"cocktail party effect",
", which was used for quite a while to guide ",
"attention research",
". Have a read through both of those links, they should give you your answer. If you have any more questions, feel free to ask."
] | [
"We have an attentional matrix - dedicated brain pathways to focus and attention -- always scanning all the various sensory inputs to see what is relevant to 1) our survival, and 2) our cognitive interests.\n",
"http://www.ncbi.nlm.nih.gov/pubmed/18025955",
"\n",
"http://brainblogger.com/2013/08/22/what-you-h... | [
"put simply, the brain responds to stimuli based on the priority of said stimuli. when you hear your name in a conversation, outside of the one you are having, your attention shifts due to cognitive interest in possibilities that may occur from this new stimulant."
] |
[
"If an asteroid passed through the 36,000km satellite oribtal plane, would it sweep through destroying satellites or is it likely to just pass through and not touch anything? How densely filled is this satellite region?"
] | [
false
] | article got me thinking. If it was passing a bit closer to Earth, would it be putting lots of satellites at risk? | [
"Let's do some maths!",
"Google says that there are 402 satellites in geostationary orbit at the moment, and if we assume they are evenly spread around the world; that gives us one satellite every 36000km x 2 x pi / 402 = 562 km (350 miles). ",
"Now think about a town which is about that distance away from wher... | [
"A minor detail: The 36,000 km are measured from the surface of Earth, to get the radius you have to add 6,000 km to get 42,000 km."
] | [
"Here's something to keep in mind which I think is a pretty good example of how empty space is:",
"If you flew through the asteroid belt in a spaceship, you'd likely never know it. The asteroids inside are often millions of kilometers apart, and only collide regularly on geologic timescales. Hollywood has lied to... |
[
"Do babies get hungry when they smell food they have never eaten yet?"
] | [
false
] | I have a couple of 9 month old twins who have just recently started eating basic stuff. Last night we went to pick up a pizza for dinner. Driving back, with my wife carrying the pizza box on her lap and the twins in the back seat, the amazing smell just filled the car, and I had all sorts of thoughts about what I'd do to the pizza when we got home. But what about the babies? Would their brains interpret that smell as delicious food if they've never had pizza? I imagine I had the reaction I had because I knew it was a pizza and my brain could do its thing based on that info. How would that work for the babies? | [
"\" I imagine I had the reaction I had because I knew it was a pizza and my brain could do its thing based on that info\"\nwell, actually it doesn't work that way, or not entierly.",
"\"But what about the babies? Would their brains interpret that smell as delicious food if they've never had pizza\"\neven if you h... | [
"This is an excellent question and I'm going to try to answer it in two parts - how the smell affects you and then how it affects an infant. If I don't answer you fully, let me know.",
"First up, what is happening to you (or any other adult) when you smell something strongly? It is well-established that smell is ... | [
"Awesome. Thanks for the reply and the article! "
] |
[
"How low cortisol affects on your mood?"
] | [
false
] | I'm currently on the process of investigating on why I have trouble producing cortisol, but due to me getting infeccted by covid-19, this had been postponed, so I wanted to know why even though I have trouble producing the stress hormone I am so stressed. I have generalized anxiety and recently I have been really angry about some stuff, not like angry enough to break material items but a standing anger, since last Friday, and before that I already was experiencing an easyness to be bothered by silly things like specific noises. Is this normal? Wasn't I supposed to be more chill due to my lack of cortisol? | [
"It would be more accurate to consider cortisol ",
" with stress rather ",
" it. In fact, it would be more accurate to say cortisol level is raised ",
" stress. The hormone does a lot of things, but on the whole, it helps your body to deal with stress better. This include raising blood sugar level, pumping mo... | [
"It’s a pretty general term, basically, it’s anything that throws your body off from its normal state. This can be anything from an injury, an infection, other illnesses, to mental stresses, which could be described as external situation that makes you feel you have to do something in response, something which coul... | [
"What is stress then? How does it harm us if cortisol is not present?"
] |
[
"Are human bodily fluids lethal to any plants/animals/organisms?"
] | [
false
] | A lot of plants and animals that have their own defense mechanisms like venom or other bodily fluids. Do humans have any bodily fluids that are lethal to other plants or animals? | [
"Saliva",
" has a number of antimicrobial factors, including antibodies and enzymes."
] | [
"No, it would not kill every plant you urinated on. It can kill certain species, but not every single one since you can only urinate so much and it would have to be extremely concentrated with certain toxins present to be acidic enough to kill every plant, but then it would end up killing you if it was that concent... | [
"No, it would not kill every plant you urinated on. It can kill certain species, but not every single one since you can only urinate so much and it would have to be extremely concentrated with certain toxins present to be acidic enough to kill every plant, but then it would end up killing you if it was that concent... |
[
"What are the effects of strong magnetic field on a human body?"
] | [
false
] | [deleted] | [
"You can actually see a bit of a demonstration of this on Earth. If you have a tattoo, especially one with red ink, you have to be careful about getting an MRI scan. The rapidly fluctuating magnetic fields (which are usually about 0.5-3 T) can induce current loops within the iron-rich ink, which can cause burns. No... | [
"The rapidly fluctuating magnetic fields (which are usually about 0.5-3 T) can induce current loops within the iron-rich ink, which can cause burns.",
"Most medical MRIs have a static magnetic field in that range (1.5T and 3T being most common; some research scanners go higher), but this main field doesn't oscill... | [
"Thank you for this awesome answer! ",
"Could you elaborate just how a human would die? I imagine we would \"dissipate\" in a way? I always wondered what would happen to the molecular bonds. Lastly, I'd appreciate it if you could recommend a book on the topic of pulsars for someone with a firm grasp of mathemat... |
[
"If a pregnant woman gets sick, does the baby do so as well?"
] | [
false
] | If a pregnant woman gets, say, a cold...does the baby get the same cold? How does any given illness affect a fetus? | [
"Although you say HIV, I IIRC it's only transferred at birth, not during the pregnancy. There are some pretty effective barriers to help protect the baby, not only from pathogens but from the mothers immune system."
] | [
"It depends on the illness I think. Not all your illnesses are because of pathogens in your blood, so they most likely won't affect the baby (I think cold doesn't for that reason, please correct me if I'm wrong).",
"But there are some very bad illnesses which if the mother gets can totally screw up the baby. Obvi... | [
"You're correct. And even still those barriers are deliberately leaky when it comes to some things. Mother's immune cells can't pass the placenta, but mother's antibodies can! (some types, at least.)"
] |
[
"AskScience, I suck at physics. Is it possible to calculate how long it takes for matter to change phases?"
] | [
false
] | null | [
"Great idea! It seems like a reasonable approximation, but it might be off because the heat loss will be quicker for hotter objects. If you focus on the temperature change closer to the boiling point (instead of the whole range from 20C to 100C) you might get a better approximation."
] | [
"Yes. But you need to know a lot of information to do so.",
"Also, in your question you say \"reduce the mass of the liquid to the mass I want.\" I think that you are mixing up science terms."
] | [
"No, latent heat is how much energy it takes the water to change phase.",
"The amount of heat you're putting in needs to be calculated from the flow of heat from the hot plate to the water, which depends on the thermal conductivity of the container.",
"You also need to figure out how much heat you're losing at ... |
[
"Auditory and Visual Hallucinations?"
] | [
false
] | null | [
"Sorry but this falls under medical advice. Since this is against the reddit TOS I have removed it. Please speak to a doctor as it is the best course of action."
] | [
"I just wanted a discussion on this topic. I'm an artist, and this is common. I wanted people to discuss the science and spiritual aspects. I just been getting the same thing though. 'Go see a doctor.'"
] | [
"If you made the question more general and removed you as the subject that would be better. If it was a general question that didn't relate to you on a personal level the question wouldn't be medical advice."
] |
[
"Why do I feel tired throughout the day and then get a \"second wind\" at night?"
] | [
false
] | null | [
"If I'm not mistaken, I believe the cycling of the body temperature is correlated with it. At the time when you feel the most tired (the afternoon -- when people take ciesta), your body temperature is the highest.",
"http://en.wikipedia.org/wiki/Circadian_rhythm"
] | [
"This is right. Transcriptional control of our clock genes (those that control, essentially, the many functions of our circadian clock) occurs in a cyclical fashion that is different for many of us. The interplay between two factors is what usually defines our personal rhythm: sleep-wake cycle and core body tempera... | [
"How long have you sustained this sleep schedule? If you went to bed at 3 AM for a year or more, it's gonna take a good while to fully adjust to this sleep schedule. The ideas of day and night people are not fully supported by sleep studies, and should not effect you to the point that it is. If it's been a while si... |
[
"Can bacteria grow on soap?"
] | [
false
] | Most likely we wont find any bacteria on "anti-bacterial" soap but what about regular bars of soap we use in the shower? | [
"Definitely. Soap's function is not generally to kill or even remove bacteria from your body,though, but rather to make insoluble oils, fats, and greases water soluble.",
"The vast majority of bacteria you come in contact with either have zero effect on your overall well-being or are helpful (sometimes even vita... | [
"It is estimated that 500 to 1000 species of bacteria live in the human gut and a roughly similar number on the skin. Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in the body (approximately 10",
" versus 10",
" The mass of microorganisms are... | [
"its not really necessary to cite such widely known facts. Every piece of shit that comes out of your anus has billions of bacteria. There are Staphilococcus aureus living in your nose and god knows what living in your bellybutton. The bulk of your commensal flora (as it is called) is in the gut of course, where it... |
[
"Is a certain Sleep position considered healthier or beneficial?"
] | [
false
] | Back, side or front? Or does it matter? I was always told that sleeping on your right side helped with stomach aches. Is this true? Any longitudinal studies or research about sleep positions would be appreciated! | [
"This is really dependent on situation. As another poster commented, sleeping on your left can help with acid reflux. Additionally though:",
"Pregnant women are advised to sleep on their left side to prevent supine hypotensive syndrome. ",
"Obstructive sleep apnea can be exacerbated by sleeping on one's back.",... | [
"Sleeping on your left side has been shown to help with conditions like acid reflux. A couple of references ",
"here",
" and ",
"here",
"."
] | [
"An elevated head position is typically of benefit for patients with OSA as well."
] |
[
"Why electrons in atoms are not emitting energy?"
] | [
false
] | They are charged particles, so if they are experiencing acceleration they should, and any way they are moving around the atom they will experience it, even if they're in their lowest energy states. I understand that in quantum physics, due to Schroedinger equation, electrons' locations are static fields of probability around the nucleus and so are their charges, but that seems to only take into account their wave properies, completely neglecting the fact that they are also particles. So shouldn't there be some some explanation in the classical sense also? | [
"electrons should be able to have lower energies than the minimum",
"Then it wouldn't be the actual 'minimum', would it? But semantics aside, it's ",
" impossible for an electron to have a lower energy than its ground state, the Variational Theorem. ",
"the lowest state [..] is just minimal amount of energy t... | [
"..., so if they are experiencing acceleration ...",
"Yes, ",
". They are not. That's the reason they do not radiate.",
"More broadly, classical radiation such as the kind generate by an accelerating charge is proportional to the square of the acceleration. The expectation value of the electron's position ... | [
"I agree that it's unintuitive, because of what we know about classical systems. If a classical particle (say a little ball) had the same probability distribution, we would interpret that to mean that the ball was moving around the center of force, experiencing acceleration, and spending equal time in every little... |
[
"Does every chemical reaction emit a sound?"
] | [
false
] | There are several reactions/experiments known for making certain sounds, but are other (or just specific) reactions actually silent or does every chemical reaction emit a measurable sound? | [
"Sound is basically vibration. Vibrations that result from some source of displacement. In an abstract sense, even molecular movements like an enzyme changing its conformation create 'sound' in that when the energy resulting in the physical change is released and some of it is displaced outwardly to the environment... | [
"Im guessing you're referring to things like the barking dog experiment. ",
"In general reactions, unless they're very exothermic and fast (ie explosions and combustion), tend to be pretty dull. In order to make a sound you need to move a lot of air, and this is generally accomplished by by rapidly heating it. So... | [
"No chemical reactions emit any particular sound in-themselves."
] |
[
"How valid is the framework behind the Drake Equation?"
] | [
false
] | null | [
"It's really not very subtle or arcane; it's just how fractions are multiplied."
] | [
"Right, but then are the variables chosen accurate in providing the probablity of life out there?"
] | [
"Yes, unless life can form independently of planets."
] |
[
"how is Thiomersal degraded? also, what is the mechanism of mercury toxicity?"
] | [
false
] | after some arguing with my father (a psychiatrist) about the possibility of vaccines that can potentially contribute to mental diseases like autism (he thinks they contribute, i don't), he pointed me in the direction of Thiomersal, a preservative in vaccines, which is apparently based on mercury. my question is this: how is this compound metabolized, if at all? my second question is this: how exactly does mercury cause toxicity? i have an extensive biology background, so get technical! | [
"Thiomersal is metabolised into ethylmercury which is excreted about ",
"six times faster",
" than ",
"mercury which is found in fish. If you were to look at say, the 2009 pandemic flu vaccine that contained 25 ug of mercury which would cause less exposure than eating a can of tuna. ",
" ",
" ",
"in the... | [
"Wasn't Thimerosal cut from the ",
"grand majority",
" of vaccines? There are very trace amounts, at best. It's more dangerous to eat a can of tuna because it contains more mercury ",
" you might slice yourself on the lid. "
] | [
"Mercury is toxic because it binds very strongly to the thiol groups in the active sites of enzymes which not surprisingly throws a wrench into the works if there's enough Mercury around. In the human body it is metabolized to the EthylMercury cation. Thiomersal is a Mercury based preservative that is used in som... |
[
"Why do mushrooms grow in a circle?"
] | [
false
] | I have noticed several circles of mushrooms in my field. What causes it? | [
"\"Subsequent generations of fungi grow only outwards, because the parent generations have depleted their local nitrogen levels.\"",
"From ",
"Wikipedia",
"."
] | [
"Potentially something to do with the pattern of spore dispersal? Combined with other factors such as localised nitrogen and other nutrient depletion it might lead to that pattern. "
] | [
"These are called fairy rings. The mushrooms you see are all most likely part of the same fungal thallus (body) that started from a single spore in the middle. Each year the ",
"mycelium",
", composed of threadlike ",
"hyphae",
" expand outwards.. When the fungus sends up ",
"fruiting bodies",
" they... |
[
"If conciousness is not a continued stream, why do I always feel like I am waking up in the same body everyday?"
] | [
false
] | null | [
"I don't understand what the potentially discrete nature of consciousness has to do with other bodies..."
] | [
"Ill expand. In the transhuman subreddit I read people claiming that if an exact copy of your brain was uploaded, your copy would still be \"you\". They claimed that becuase there is no soul, and the concious mind is just a product of the physical brain (things I believe to be true) that your copy would also have y... | [
"Yeah we don't have any empirical evidence for any of the buddhist stuff. As for uploading or copying consciousness, we don't have any way of doing that so we don't know what will happen. Most neuroscientists are physical realists though meaning that they believe that consciousness is the result of physical process... |
[
"\"Back in the 80s, all those scientists told us we were about to enter another ice age. now they say the earth is heating up instead. they don't know what they're talking about, so I don't believe any of this global warming business.\""
] | [
false
] | A family member recently told me he refused to believe in global warming because when he was a kid, he was taught that scientists believed the earth was in the middle of entering another ice age. I was completely thrown off, and had no good response. Reddit, can you help fill me in on what in the world he's talking about? He can be a very reasonable guy, but is stuck in this mindset based off something he heard decades ago. I'd love some help clearing up the facts so he can get on board with modern science. | [
"This tracks back to a myth that there was broad scientific belief in the 1970s that the earth was due to enter another ice age. It stemmed from a few studies about the specific timing of ice age cycles. The findings got picked up by the popular press and published in ",
"Newsweek and National Geographic",
". ... | [
"That's fairly impressive. The idea that humans would be capable of completely up-ending something as big as the planet's ice age cycles/radiation balance (I like the second term better, thanks). ",
"I'm planning on sitting down with him soon and walking through what scientists know today. I plan to start with ",... | [
"This whole site is good: ",
"http://www.skepticalscience.com/ice-age-predictions-in-1970s.htm"
] |
[
"What's the difference between a hydrogen ion and a regular proton?"
] | [
false
] | null | [
"A ",
"H",
" ion is the same thing as a proton."
] | [
"While H+ technically means a proton, in chemistry, a proton generally cannot exist as a 'free' proton due to high charge density. Hence, it tends to bond with solvents which most commonly is water to form H3O+ which chemists just shorthand write as H+."
] | [
"I remember being confused about various things ”exchanging protons” in highschool chemistry. It sounded like nuclear reactions which I knew didn’t happen in chemistry. Took me a while to realize they were talking about H",
" ions!"
] |
[
"If the fastest that neurons can oscillate at is a few hundred Hz, then how can we hear and process sound frequencies up to ~20,000Hz?"
] | [
false
] | null | [
"Frequency is translated not by how fast a neuron fires, but by which neuron fires.",
"Within the ear, the cells that detect sound waves are called hair cells; different hair cells get triggered by different frequencies of sound."
] | [
"To expand a little, the cochlea is sort of snail shell shaped, and if you were to unroll it, you can see that it starts out pretty wide and gets narrower. This makes it so that different parts of it resonate at different acoustic frequencies. There is an animation somewhere that plays a melody, and you can watch t... | [
"That's like asking \"how can we see so many colors if all neurons are gray?\"",
"The properties of neurons are not relevant here, because information is encoded. The cochlea contains hair cells of different lengths. Long hairs detect low frequencies, short hairs detect high frequencies. These cells then transmit... |
[
"Do you think there are any concepts in math (& science) that can not possibly be represented visually?"
] | [
false
] | null | [
"As far as physics goes, basically all of them. The language of physics is maths, not pictures. To the extent we use pictures at all — Feynman diagrams are what I'm talking about here — they are purely a tool used to facilitate the writing of equations."
] | [
"What precisely do you mean by \"represented visually\"? Visual representations understandable without context are inherently Euclidean in less than 3 dimensions; anything which is not this (and the ",
" majority of math and science is not) cannot be fully represented visually. I don't think that's what you're as... | [
"I think he's talking about stuff like hypercubes. Things which are very difficult to illustrate, even in a layman-like way."
] |
[
"Is our moon relatively large, average or small, given the size of our planet, and the sizes of moons we've been able to observe orbiting other planets?"
] | [
false
] | I've always wondered this, and watching a couple of shows recently on the formation and theoretical origins, it just stands out to me that our moon is fairly large in comparison to Earth. Is this the case? | [
"Our moon is rather large on the scale of moons we have knowledge about. ",
"Actually our moon is the 5th biggest moon in the solar system. ",
"http://en.wikipedia.org/wiki/Moon",
"Edit: missed the \"5th\""
] | [
"This is not correct. Our Moon is substantially less large than ",
"other moons in the solar system",
". However, it is the biggest ",
" to the size of the planet about which it orbits."
] | [
"oops, i missed the 5th in my sentence.. that changes things quite a bit. Thanks for the heads up. "
] |
[
"Why do astrophysicists think that black holes have singularities? Wouldn't it be more likely that there's just a volume of ultra-dense matter?"
] | [
false
] | null | [
"GR predicts singularities. That being said, most physicists would agree that GR is a classical theory which is expected to break down at small scales. So many, if not most, physicists probably don't believe that singularities really exist."
] | [
"Neat, is there any difference from an outsider’s perspective whether or not there’s an actual singularity or not? Does it change anything about what we know about black holes?"
] | [
"Physical singularities (as opposed to coordinate singularities) are present in any set of coordinates. So all observers agree that there's a singularity there, according to GR."
] |
[
"What causes the discomfort of not breathing? Lack of oxygen or lack of air?"
] | [
false
] | If our bodies was constantly given fresh blood filled with oxygen, would we still experience the discomfort of holding our breath? Is the uncomfortableness directly linked to oxygen content in the body or is it a defense mechanism created by our bodies to prevent not breathing? | [
"When you hold your breath CO2 will start to accumulate in your blood. The CO2 will react with water creating HCO3- en H+. This will lower the pH of your blood. There are several receptors in your system (Chemoreceptors) who will detect the lower pH, this will make them overwrite the impulses given by you to stop b... | [
"CO",
" + H",
"O ⇌ H",
"CO",
" ⇌ HCO",
" + H",
"The pKa of the carbonic acid (H",
"CO",
") formed from the aqueous CO",
" is such that at physiological pH, it acts as an acid. It donates a H",
" to solution (lower pH) and the bicarbonate is merely the resulting conjugate base."
] | [
"It's important to know that breathing is largely regulated by CO2, not oxygen. For example, you can trick your body into thinking that you don't have to breathe by hyperventilating (breathing in and out very rapidly) and getting rid of a lot of CO2. You can do this if you're snorkeling, but you then run the risk o... |
[
"Is everything always in equilibrium?"
] | [
false
] | [deleted] | [
"This is one of those times where the answer is a simple \"no.\""
] | [
"If everything was in equilibrium nothing would happen. The second law of thermodynamics implies this will eventually occur - ",
"http://en.wikipedia.org/wiki/Heat_death_of_the_universe"
] | [
"This question could mean a number of different things. From a chemical perspective, no. Given enough time, things try to reach equilibrium, but they are not always in equilibrium. Think of putting ice in a cup in the summer. Equilibrium is reached when the ice has melted and is at the same temperature as the envir... |
[
"Can someone explain linkage disequilibrium to me?"
] | [
false
] | I am in grad school for bio-engineering. It's a long story, but out of curiosity I decided to take this obscenely intense genetics class. I'm trying to wrap my head around linkage disequilibrium, but can't really grasp the concept. | [
"It's basically a measurement of the extent to which alleles at different loci associate with each other. If the two alleles do not associate in any way, the frequency of all the possible haplotypes should be based solely on the frequency of each allele (this is the expected distribution). If they do associate, how... | [
"In my opinion linkage disequilibrium is just another in a long line of awfully named biological phenomena.",
"First, linkage is a term that describes the physical connection of two genes on a chromosome. Because chromosomes segregate independently during meiosis, genes located on different chromosomes will be ",... | [
"Thanks for your help! I'm just trying to calculate LOD values for haplotypes, it's just sort of confusing despite hours of googling and reading journals.",
"I'm at univ of utah. Everyone said it was a mistake to take courses outside of engineering for a grade. Im now panicking in this Molecular Biology class whe... |
[
"Where does the energy from sound go?"
] | [
false
] | I know it's a fairly simple question, but what is the final resting place of sound? | [
"The same as all other energy- heat. Heat is basically the final version of all forms of energy. "
] | [
"What is sound? It's a wave travelling through a medium (typucally, through air). As it travels, depending on the period and amlitude of the oscillations, we perceive different sounds. ",
"During the compressions, atoms are hitting each other more frequently than normal, so eventually all the extra translational ... | [
"so if a sound is loud enough will you actually feel a temperature change? If so, how loud of a sound would be needed?"
] |
[
"Could the Kessler Effect be observable from earth?"
] | [
false
] | What might it look like? Would it require a telescope? | [
"It would not be observable to the naked eye.",
"Some satellites are visible to the naked eye as dots though most are very dim. The ISS may appear as a very bright and very fast moving dot, there are websites like ",
"heavens-above.com",
" that can predict when it will be visible in your area.",
"But if you... | [
"Could it lead to something like a never ending slow meteor shower as pieces re-enter?"
] | [
"Worth noting that the worst debris situation right now is at altitudes between 600km and 1000km. It might take decades or probably even a century before the lower fragments' orbits decay low enough to reenter the atmosphere. There will be lots of further collisions in the meantime.",
"It's really hard to predict... |
[
"For any set of points on a graph, is there a polynomial that passes through each point?"
] | [
false
] | I was thinking about Brithey Spears rock solid hit "Hit Me Baby (One More Time)", and if it could be described with a mathematical polynomial. It is 210 seconds long. In 16-bit, 44,1KHz audio that means 9261000 points, one at each step of the x-axis, where y would be a vaule from -2 /2 to 2 /2. Is there hypothetically a polynomial that passes through each of these points? Can we estimate how many parameters it would have? | [
"For every finite set: Yes. In general you need a degree one less than the number of points N - sometimes you can get away with lower degrees of course. A polynomial of degree N-1 has N free parameters, you get a system of N equations for all N points, which leads to a unique solution as long as the x-values of al... | [
"Yes, these are the Lagrange polynomials. You can always fit a polynomial to any finite set of points.",
"https://en.wikipedia.org/wiki/Lagrange_polynomial"
] | [
"One interesting use of this is for ",
"-of-",
" secret sharing schemes. Let's say you want to distribute your secret will, backup password, or something to friends in case you die / are captured by the mob / whatever. Or the nuclear launch codes can only be accessed by a quorum of leaders, etc. You can set up ... |
[
"[OPTIC] Why does every measurement of a system that contains coupling/transmission is approximated through a lorentzian function?"
] | [
false
] | I often read that something in the field of optic gets measured and then gets least-square fitted by a lorentzian functionl. I think it was always with coupling/transmission etc. hence the question, since I didn't find any source and everything that I found just stated that they did it. | [
"The reason Lorentzians pop up quite a bit in optics is that they describe the behavior of what is called a Lorentz oscillator. The basic idea is that to a first approximation you can treat an electron-bound to a nucleus as a simple vibrating spring. When if you stretch (or squeeze) the spring, there is a force tha... | [
"It is generally true for any driven, damped, harmonic oscillator, as these are what is described by the model (equation) above. (E.g. not necessarily optical.) See the Wikipedia page on Harmonic_oscillator.",
"Note that small oscillations can almost always be approximated by a harmonic oscillation; note that alm... | [
"But why can we describe a system containing of two waveguides and a ring resonator like that?",
"Is it generelly true for absorption around a resonance?",
"Is there a simple System that doesn't follow this model?"
] |
[
"Refrigerator with a vacuum or inert gas?"
] | [
false
] | I was reading recently that the reason we need to keep foods covered in the fridge is that the flow of oxygen promotes the growth of harmful bacteria. Was just wondering if it might be feasible to have a fridge that maintained an interior vacuum or else an atmosphere with an inert gas? Anyone have any thoughts on advantages/disadvantages/implementation issues? | [
"In a vacuum, liquid water simultaneously boils and freezes solid. This could potentially cause some foods to explode. ",
"In areas that were exposed to enough radiant heat or light (assuming the wall of the vacuum container were above 0 degrees C.), the remaining frozen water would slowly sublimate, converting d... | [
"On the plus side, it would be a fully functional freeze drier. They use lowered pressure to speed up sublimation, but freeze it first so nothing explodes or boils."
] | [
"Good answer! Thanks for satisfying my random curiosity :)"
] |
[
"What causes dark circles under eyes?"
] | [
false
] | I’ve always been really curious what the actual physiology of dark circles is but every way I’ve ever tried to look it up just tells me that dark circles are caused by lack of sleep. | [
"Cortisol. When you become excessively tired your body releases cortisol to try to amplify sugar in the blood. Two side effects happen, blood volume increases and some vessels dilate (others constrict). The vessels under the eyes engorge which results in the bluish tint increasing (like when you see veins under the... | [
"The skin near you eyes is very thin, therefore the capillaries are prone to mistreatment. Therefore the skin under your eyes is easily susceptible to being bruised and overused creating the dark circles that indicate lack of sleep. Your eyebrows however are very tough which prevents the darkness from traveling upw... | [
"Depends on the conditions and how tired someone is, when they ate last....that kind of stuff. Cortisol and ACTH have weird effects on skin pigment because they can also control melanin production. So patients with Addisons can end up with hyperpigmentation. The eye thing is always more pronounced when tired becaus... |
[
"I want to make a cryostat less sensible to vibrations with attaching it to rubber bands. How do I find the optimal spring constant for damping these vibrations?"
] | [
false
] | null | [
"\"I will also add a damping pad\"",
"You may need to take account of this in your calculations. This is effectively another spring underneath your mass."
] | [
"I thought of that to.\nTo be honest, I've worked in this lab for just one week and I've never had any other experiences. So this is all very new to me. I was said to find rubber bands which optimize the damping. That's all."
] | [
"I may be missing something here but I think elastic bands are the wrong approach (and in my tired half asleep state) it seems like they couldn't really work as they would act as harmonic oscillators and only reduce oscillation a tiny amount.",
"There's ",
"some more info on damping here",
". I suggest you ",... |
[
"Why can or can't I move differentials around an equation?"
] | [
false
] | I am currently working towards a bachelor's in mechanical engineering and I was wondering about calculus differentials. Quite often in class, we move them around freely and a professor will say something along the lines of "If you are a mathematics major, this probably makes you cringe. Technically you can't move differentials around but we can in this field." (physics or engineering) So basically my question is why is it that you cannot technically move them around, yet I do it all the time when solving problems? | [
"You ",
" move them around because the objects you are working with, dx's and df's and such, are vectors not numbers (technically, families of vectors). You can add vectors together and you can multiply them by scalars, but you can't divide them or multiply two of them together. In multiple integration dxdy does ... | [
"You totally can. Well you can't because you haven't justified it, but it can be justified fully. A common way that it is formalized is used by people who study geometry, or differential equations, through something called a 'differential form', which requires concepts from vector calculus. There is a quick and dir... | [
"Thought they would mention them in the article, but the ideas are similar enough for these purposes, I'll edit the post."
] |
[
"How Exactly Does Prion Disease Kill?"
] | [
false
] | My friends and I were talking about cannibalism the other day and Kuru came up. I've looked around and haven't found anything that plainly states how exactly the disease kills. Same with Mad Cow. I know prion disease is the prion converting normal proteins into prions but why exactly is that lethal? What does that do? | [
"For kuru, and Creuztfeldt-Jakob disease, the reshaped prion proteins form aggregates in the nervous system. Disrupting whatever native function it had (that we still are not certain of). And damaging the cells, resulting in the spongiform pathology that is characteristic of it."
] | [
"Prions are misfolded proteins. All cases that I know of in mammals are neurological. Prions are also infectious. \nThe problem arises when they transmit their misfolded shape to other normal functioning proteins (their mechanism isn’t for sure, but I’m sure you can find mechanism theories on Wikipedia). These misf... | [
"Prion disease has somewhat of a domino effect.",
"\nOnce prions are introduced into the system, they can trigger misfolding in similar proteins. This will cause a buildup of plaques and leave the person with proteins that aren’t able to carry out their intended role which is never a good thing. ",
"We still do... |
[
"How does taking creatine improve your cognitive performance?"
] | [
false
] | null | [
"Read here",
", scroll down to the neurology section. With a normal diet and without any pathological condition, your body gets/generates enough creatine for brain use and a dietary surplus is not taken up into the brain. As to how it works, I think the relevant section is:",
"Creatine, through its ability to a... | [
"It is made from amino acids, it's primarily used for energy, particularly for muscle energy, I'm not 100% sure it helps overly much for the brain, but I guess if it did it would be due to the extra energy to keep concentration."
] | [
"it doesnt."
] |
[
"Does Jupiter have a solid core of anything or is it truly just a large ball of gas?"
] | [
false
] | null | [
"So first off...",
"is it truly just a large ball of gas?",
"We know for sure that this is not true. At the pressures and temperature in the interior of Jupiter, hydrogen turns into a liquid metal. In fact, by mass, Jupiter is ",
" liquid metallic hydrogen. It's also the only thing that can explain Jupiter's ... | [
"It probably wouldn't be too useful of an experiment. Our current weapons would have to be dramatically redesigned to even hope to survive the pressure deep into Jupiter's atmosphere. One could always just drop a large, subcritcal sphere of fissionable material into the atmosphere that is designed to compress to a ... | [
"Hi, forgive the ignorance but wouldn't it seem more likely that Jupiter had a solid core? With Jupiters strong gravity it would have caused many asteroids to fall in and slowly sink to the centre causing a build up. "
] |
[
"Will a person who moves to a place located on a higher altitude become taller?"
] | [
false
] | Astronauts living on ISS become taller from the low gravity. Is there a measureable difference in height for people moving from for example sea-level to 4000m above the ocean? | [
"You are confusing low gravity with microgravity. If you were at the same height as the ISS and not noving, you would experience gravity similarly as on earth and fall towards the earth just the same. The change would be negligable. The reason people grow taller in space is because the space station is orbiting fas... | [
"When in orbit, a person in a spacecraft experiences 'zero gravity' because their spacecraft accelerates exactly as much as they do. Therefore, they go from an apparent gravitational acceleration of 9.81 m/s",
" to 0 m/s",
"When moving up 4000m, a person still experiences significant gravity from earth. Assumin... | [
"An astronaut can grow up to 3percent height in space - from a reduction of gravity from 9.81 to 0m/s. Factoring an effect of 0.13% of it, it would give you an effect of 0.0039%. Taking an average height to be - say 170cm, it would give you a result of 0.00663cm growth - a negligible difference. It would probably ... |
[
"What is faster the speed of light or the expansion of the universe, and why?"
] | [
false
] | null | [
"They are not directly comparable - the speed of light is a measurement with units of <distance per time>. The expansion of the universe is a measurement with units of <distance per time per distance>.",
"So comparing one to the other is sort of like comparing a car's speed to a car's acceleration. The value you ... | [
"Speed of light is essentially the speed of massless particle. It just so happens that the most visible massless particles in the universe are photons. This is the reason why \"speed of light\" is a universal limit and you can't exceed it. It's the speed of massless matter moving through space. ",
"The expansion ... | [
"Also to add, when imagining the expansion of the universe, don’t imagine an edge speeding outwards. It’s not expanding into anything. It’s space itself which is expanding. Imagine yourself on the surface of a balloon covered in dots. When the balloon expands, the space between the dots expands. \nThe speed of ligh... |
[
"How are tectonic fault lines locations deduced and to what accuracy are they known?"
] | [
false
] | I was looking at maps of the San Andreas fault line and I don't understand what the line on maps represent. Is it meant to estimate the tectonic plate boundaries and if so what does it mean, is the place where one plate submerges under the other? What's the process from earthquake data to creating this line? | [
"Faults",
", in the upper portions of the crust where rocks behave like brittle materials (i.e. where they break), are discrete planes representing a discontinuity across which displacement has occurred (i.e. rocks have moved past each other along the fault). In many cases, these can be incredibly clear as they h... | [
"I just want to thank you for taking the time to write this detailed answer"
] | [
"This is an amazingly clear answer. Thank you!"
] |
[
"What causes a headache?"
] | [
false
] | [deleted] | [
"The brain is lined by a protective covering kown as the meninges. Since the brain doesn't have any sensory innervation itself, the meninges have all the sensory information associated with pain. Basically, whenever the meninges are irritated, this can cause a headache. There are a wide variety of things that can i... | [
"Thank you for the quick response. I had actually had done a DANCON March for 22km earlier so that may have caused it. Keep up the good work. "
] | [
"Why do I get a headache during caffeine withdrawal? "
] |
[
"Does \"letting the flavors blend\" actually work? And if so, what's going on?"
] | [
false
] | Lots of recipes for salads, coleslaw, or soups say to leave it in the fridge for a few hours so that "the flavors can blend together". But surely, between my mixing and the turbulent blending of the air before reaching my nose, everything I can taste/smell should be blended already, even if I eat it right away. Are people deluding themselves, or is there something else going on here? | [
"think of it more as infusing than blending. If you drank tea a few seconds after adding water, it would be very, very weak and the longer you let it sit it gets stronger. With something like salad dressing, it takes a bit of time for the flavour of herbs and spices to infuse through the oil."
] | [
"I'm 99% sure it was an article in America's Test Kitchen where they answered this exact question. However my Google-Fu is lacking as I cannot find it any where online for free. (A couple of hits for \"food chemical reaction\" came up on Amazon but that's it. ATK is also behind a paywall.)",
"However in their art... | [
"It definitely works. You are allowing time for a few things. Depending on what the ingredients are, there may be chemical reactions occurring. Acids and bases may be reacting for instance.",
"Also, flavors will mix together. Take a sauce for example. For simplicity, take something like olive oil. Now add chunks ... |
[
"How does a tunnel boring machine navigate?"
] | [
false
] | I've been looking at some videos and progress with the new light rail tunnels in and around Seattle, and it got me wondering how the heck they manage to bore through solid rock for miles and pop out exactly where they mean to. Most of the techniques traditionally used for navigation (GPS, cell radio triangulation, magnetic fields, stars, lasers, barometric pressure, etc.) would all seem to be completely useless underground in solid rock. How do you get a machine like that to maintain a straight and level path, when do you tell it to turn, and how do you make it line up with it's exit? | [
"You are saying \"can surveying really be that precise?\" The answer is yes. Even traditional surveying can. With the aid of lasers and/or modern optics, it gets even a bit easier."
] | [
"I understand the basic principles of surveying, I guess the thing that gets me is seeing a machine break through a solid hillside, dead-centered inside of a metal ring that's already installed to complete the tube. I can understand boring straight through a hill, I know that's been done for a long time, but diggin... | [
"People have been making straight lines without the technologies you mentioned for thousands of years. The techniques for doing so fall under the umbrella of ",
"surveying",
".",
"To figure out which direction the straight line needs to go in, they use one of ",
"these",
". It basically measures the effec... |
[
"Would it be possible for the universe to stop expanding and begin shrinking?"
] | [
false
] | I read a post on askreddit or something that said something along the lines of, "There could have been a universe before ours that that stopped expanding and started shrinking into one very smell point that then exploded which was the Big Bang." Is there any real reason the universe would all of a sudden start shrinking? | [
"Absolutely; this is the idea behind the ",
"big crunch",
". Evidence suggests, however, that our universe doesn't have enough matter for its gravity to overpower dark energy which is currently making out universe expand at a growing rate. The fate of this universe seems to be one where it will continue to expa... | [
"That's dark energy, which is easy to get confused with dark matter. Dark matter is a theorised form (or forms) of matter that accounts for the fact that, in various scenarios, certain effects can be seen that appear to be the result of matter, but lack an observable material cause (this is observed with galaxies,... | [
"For the most part, yes; that's correct. ",
"There are a number of observable phenomena which shouldn't, according to our measurements of perceptible matter, be possible. The only thing you've left out of your statement is the possibility for there to be no \"missing matter\" but instead that our understanding of... |
[
"Does dark matter contribute to the mass of a black hole?"
] | [
false
] | null | [
"Yes certainly some dark matter would be gravitationally captured by black holes and some would fall in. Note that it doesn't really matter what fell into a black hole other than its mass and charge and spin, so the properties of a black hole with mass that came from dark matter may be identical to a black hole non... | [
"First Disclaimers:\n1. I am an absolute layman.\n2. Almost nothing is known about dark matter except that it appears to exist. Anything stated about how it acts is necessarily speculative since we do not know how it fits into our theoretical frameworks (if at all).",
"However, I do believe that this question ... | [
"Hello, Im late to this one, but think I can answer it as dark matter is my area.",
"The answer is yes, if we assume dark matter to exist, then it would certainly contribute the mass of a black hole. There is no way to prove this, of course, as we can't detect it yet, but we do know that dark matter is affected g... |
[
"How does external stimuli contribute to evolution?"
] | [
false
] | null | [
"How does the DNA know that it needs to create red and white spots to mimic a ladybug, when the input of information is visual by nature?",
"It doesn't work like that at all. The DNA mutates all over the place, into mostly bad stuff that doesn't stick around long. The good stuff that persists ends up in the case ... | [
"DNA codes for some protein that dertermines the pattern on the back of the ladybug. In each generation of ladybug there will be a variety of patterns, because the copy mechanism for DNA is not perfect or there might have been mutating agents like radiation or toxins. This results in mutations of the DNA sequenze a... | [
"that makes perfect sense...now I'm facepalming, duh, of course, it determines success by which variations live and die. \nHow did I somehow overlook the basic tenent of evolution. Survival of the Fittest (and lucky!) is the vehicle.",
"Thank you! "
] |
[
"Why do higher elevations have lower temperatures?"
] | [
false
] | This is probably a simple question with a simple answer but I want to know if my hypothesis is correct. My hypothesis is that at higher elevations there is more wind travel (for a multitude of reasons) therefore cooling by convection. Is this the reason, or is there something I'm not considering (maybe air density)? This is something I was truly puzzled by as a kid with the train of logic "We're closer to the sun, why isn't it hotter?". | [
"The air at lower altitudes has to hold up all the air above it, which means it has to have a higher pressure. According to the universal gas law if a gas wants to have high pressure it has to get denser or a higher temperature or both. "
] | [
"Earths atmosphere is kinda weird in that at sea level its one temperature, then it will decrease, then increase, decrease again, and finally increase on up. ",
"Seriously, here's a chart.",
" I cannot remember exactly why, but if I recall its due to the light getting absorbed at the layers of atmosphere. ",
... | [
"By this theory high altitude over Kansas or Nebraska would be warmer."
] |
[
"Whatever happened to string theory?"
] | [
false
] | I remember there was a bit of hullabaloo over string theory not all that long ago. It seems as if it's fallen out of favor among the learned majority. I don't claim to understand how it actually works, I only have the obfuscated pop-sci definitions to work with. What the hell was string theory all about, anyway? What happened to it? Has the whole M-Theory/Theory of Everything tomfoolery been dismissed, or is there still some "final theory" hocus-pocus bouncing around among the scientific community? | [
"They're still working on it. Pop sci journalism is the worst metric for discerning what people are actually working on. Or for anything, for that matter."
] | [
"I'm not sure what this \"learned majority\" you're talking about is, but string theory is still very much an active area of research, and by far the most popular and, imho, most promising approach to quantum gravity. It's a very technical subject, having strong interactions with modern mathematics, and so it's di... | [
"Well, new papers are put on ",
"arXiv",
" every day. arXiv is a preprint database (so the papers posted to it have not necessarily been peer reviewed yet, and a lot of researchers with various levels of competence can upload to it) and is the main outlet for particle physics papers today. ",
"hep-th",
" ... |
[
"If you were on the moon and traveling consistently towards the setting sun i.e. between night/day. Could you find a comfortable ambient temperature? Could you survive with just oxygen?"
] | [
false
] | [deleted] | [
"First of all, the moon has effectively no atmosphere. Therefore, aside from gravity, standing on the moon is the same as sitting out in interplanetary space. Both are effectively a vacuum, so there is no \"ambient temperature\". ",
"If you were standing on the moon without a space suit (and somehow managed to ca... | [
"One of the many layers of the spacesuit is a temperature control layer, it runs cool water around the suit to maintain the desired temperature, while an insulating layer keeps the astronaut warm enough. The suit is designed to reflect a lot of the radiant heat to minimize overheating, heat radiates off the suit sl... | [
"Ok so Im confused. What then protects astronauts from the spontaneous freezing/heating up?"
] |
[
"Is ice harder than concrete?"
] | [
false
] | I tried googling it and found that some old solid ice mass is harder, but what about an ice rink? How come a fall that's comparable to what I sustain skateboarding hurts so much more when I'm ice skating? | [
"Two parts here:",
"There are different herdnesses of most objects. Mineral content in water will affect hardness as well as temperature. In general though, ice will rate somewhere around 1.5 Mohs. On he same scale, youd like concrete to be in he 5-7 Mohs range. So, yes, in general concrte is harder than ice.... | [
"In general though, ice will rate somewhere around 1.5 Mohs. On he same scale, youd like concrete to be in he 5-7 Mohs range.",
"As you note though, ice's hardness changes with temperature. At around -80 C (-112 F, far colder than where anyone is going to skate), ice reaches a hardness of 6 on the Mohs scale, rou... | [
"It depends on the ice and the concrete. There are variables that affect each, such as trapped air, impurities in the ice, uniformity of the aggregate, etc.",
"There is a type of aerated concrete that was being developed for use at the end of airport runways that would intentionally crush under the weight of a p... |
[
"Would all intelligent life in the universe evolve using the same visible light spectrum as us to see? Is our slice of the spectrum innately superior for vision?"
] | [
false
] | null | [
"I'd say it's the most effective general range - yes, some creatures go a bit higher or lower than humans, but it's pretty close.",
"Visible light is pretty good at going a good distance through the atmosphere without diffusing too much. It's passive - ambient light is used and we don't have to project anything ... | [
"I would like to clarify that visible light is the part of the spectrum where the sun outputs most of its light. If we tried to develop eyes that saw infrared or the ultraviolet then everything would be dimmer, because there is less of that light coming from the sun. The atmosphere is equally important because it... | [
"Plenty of animals don't see the same spectrum that we do. Lots of birds of prey see UV light (helps them track prey, and many have patterns on their feathers that can only be seen in UV light). Of course dogs see a different spectrum, as do cats (why some people mistakenly think that they are \"colorblind\"). B... |
[
"Is it really bad for your health to eat in front of a computer?"
] | [
false
] | I've heard this more than once in my life, but can't recall hearing a plausible explanation. That is, one with the actual medical facts. | [
"Scientifically, no. There is absolutely no reason to think it would be.",
"But also scientifically speaking, i really doubt anyone has ever done a study on it.",
"It is unhealthy to eat a lot while sitting on your butt a lot in front of a computer a lot all day long. Easy to see why the myth could emerge. B... | [
"I remember being told not to eat at a computer in the early 90's. They just didn't want us getting food in the keyboard."
] | [
"It doesn't have anything do with the computer, but more to do with your emotions towards eating. We sit at computers a lot, and if you connect food with the computer you ",
" find yourself eating more than you should for your diet. If you train yourself to think \"I should not eat in front of my computer,\" yo... |
[
"What causes Amino Acids to \"fold\" into proteins?"
] | [
false
] | null | [
"The amino acid sequence of a protein is going to ultimately determine how it is going to fold, and the folding is stabilized by several factors. The biggest factor driving protein folding is hydrophobic interactions. ",
"If you're unfamiliar with this, its basically the same idea as when you add oil to water, t... | [
"There's nothing that says it has to be in its ",
" stable structure. Just a local minimum that's low enough in energy that the other structures with lower energy are adiabatically inaccessible; you can't reach them without adding more energy first. The particular local minimum that is reached is affected by the ... | [
"There's nothing that says it has to be in its ",
" stable structure. Just a local minimum that's low enough in energy that the other structures with lower energy are adiabatically inaccessible; you can't reach them without adding more energy first. The particular local minimum that is reached is affected by the ... |
[
"How does pixel size on image sensor influence image quality?"
] | [
false
] | Some smartphone manufacturers decided to advertising bigger pixel size as an advantage. Is it really? Let assume two sensors with the same pixel count, but one sensor has bigger pixels (and has thus a higher area). I would expect bigger pixel size to induce poor sensitivity and poor spatial resolution. The image would be too dark in low light condition (but maybe less noisy) thus requiring bigger aperture and/or longer shots. But they are advertised as being able to capture more light thanks to their bigger area, but this doesn't seems to be a valid argument taking the lens into account. i.e.: if pixels are smaller, a focusing lens will concentrate more light on the smaller area, thus increasing sensitivity (thanks to smaller capacity). Am I missing something or is it truly false advertisement? Do scientific imaging tools prefer bigger sensors to smaller sensors (at a given pixel count)? For me the actual good criteria is "active" ratio: maximizing the ratio of the sensor that is actually sensitive to light vs. the area of the sensor receiving light. Maybe bigger pixels means that the inter-pixel space is smaller compared to the size of the pixels. | [
"What you call \"active ratio\" is called the ",
", and it is true that larger pixels will generally allow for larger fill factor.",
"Ignoring any differences in fill factor (and quantum efficiency), the performance of large vs. small pixels depends on how you do the comparison.",
"You can get equivalent spat... | [
"Thanks for the explanation.",
"My reasoning for bigger pixel sizes having poorer sensitivity is because they have a bigger capacity. i.e.: needs a bigger amount of photon to provide the same voltage. For high-speed imaging I guess they use the fact that the fill factor on those sensors with large pixel elements ... | [
"Actually, the ability to convert a photon to an electron (voltage) is what is called the ",
", which is not correlated with pixel size.",
"You may be thinking of ",
", which is the maximum amount of charge (electrons) that a pixel can collect before it saturates (or even cause charge to leak into neighboring... |
[
"In a car, if I'm in 2nd gear at 3000 rpm, do I consume more or less fuel than in 5th gear at 3000 rpm?"
] | [
false
] | null | [
" You are correct. ",
" Think about it this way. When you are driving down a hill, you can remove your foot from the gas pedal, and easily maintain your speed and RPM while using VERY little fuel (if you have one of those fuel efficiency meters, it would say something like 99 MPG or more). Conversely, if you... | [
" You are correct. ",
" Think about it this way. When you are driving down a hill, you can remove your foot from the gas pedal, and easily maintain your speed and RPM while using VERY little fuel (if you have one of those fuel efficiency meters, it would say something like 99 MPG or more). Conversely, if you... | [
" you will use less fuel in 2nd gear but the mileage will be worse. The engine is less efficient at lower loads (load is lower in 2nd because vehicle is going slower). So physically the fuel used is lower. ",
" because you are not traveling very fast the MPG is actually worse, even though the engine is consuming ... |
[
"The structural determination of any molecule via a single instrument?"
] | [
false
] | I have a significant physics and chemistry background, but this isn't my subfield. I assume a mass spec/NMR setup provides enough information to determine the structure of many molecules, but has a setup been developed that allows a scientist to introduce ANY molecule and then pop out a formula, diagram, etc. for this molecule? | [
"Well, x-ray crystallography will do it, in general. ",
"I don't think you could make a setup that could do this for literally ANY molecule/substance, or at least it would be prohibitively complex. ",
"For straightforward, stable organic molecules, it would not be prohibitively difficult in principle to create ... | [
"Mass spectrometrist here.",
"There's some pretty cool stuff happening in the realm of mass analyzers that allow for traditional mass measurements (i.e. compound X weighs Y) in tandem with elucidating structural information. If you're looking for purely structural information, look into a mass spectrometer that i... | [
"One ",
" conceivably use NMR alone to determine structure. There is a plethora of experiments one can do do gain bonding and spatial information, so it certainly goes beyond the simple NMR spectra one might think of.",
"However, like ",
"spinningspinning suggested",
", no instrument can accept ",
" type ... |
[
"How do you mass produce an antiserum?"
] | [
false
] | null | [
"You can't - to do so would be equivalent to farming people like they do in the movie Daybreakers. This is because antiserum is defined as the blood serum of naturally immune individuals.",
"You can, however, do something that would approximate the same effect. It is possible to extract and isolate the B-cells re... | [
"Nope, you are absolutely correct. If you have the sequence of the variable region of the antibody, you can express ",
"scFv",
" (single chain antibody variable fragments) in E.coli and have it secrete into the periplasm for purification. The scFv behaves exactly like each arm of the antibody and is perfectly f... | [
"Nope, you are absolutely correct. If you have the sequence of the variable region of the antibody, you can express ",
"scFv",
" (single chain antibody variable fragments) in E.coli and have it secrete into the periplasm for purification. The scFv behaves exactly like each arm of the antibody and is perfectly f... |
[
"How exactly do physicists predict masses of yet unobserved particles?"
] | [
false
] | What does it mean, when a mass of a newly observed particle fits/doesn't fit the Standard Model? Is it more about algebra? calculus? statistics? | [
"Conservation of mass, energy, spin, etc. Often a simple case of addition.",
"Scientists look at the resultants of a given interaction, and if any property is not conserved, they posit a new particle to allow the given quantities to be conserved. "
] | [
"The \"Standard Model\" is a description of all theoretical fundamental particles.",
"It organizes them so that they follow certain patterns like ",
"this.",
"It predicts how different particles react based on their properties and what properties a particle will have based on its other properties."
] | [
"For the particles listed in the table in that link, there is no way of predicting or calculating the mass (that we know of, though a lot of people are looking). However, you can calculate the mass of composite particles built up from combinations of those. For example, if you know the mass of a neutron, which is m... |
[
"Is pharmagenetic testing proven by the scientific community, or is it hogwash? It’s a genetic test to see which drugs (anti-depressants) work better depending on each individuals genes."
] | [
false
] | null | [
"It’s not a gimmick. It’s part of personalized medicine. In the past a doctor may try different prescriptions to see which one works best. Now there are tools to cut to the chase. It’s common in a variety of therapeutics, but the one I am most familiar with is chemotherapy. If there was a time limit on your life, y... | [
"The lab I worked for used to do it, we focused on 2 branches of testing, one to help those on antipsychotics and ensure they were getting the best medicine, and one to help athletes mostly in combat sports, to ensure that their supplements are all effective. It definitely isn’t fake, it does work, and there’s some... | [
"Could this expand the list of drugs already known that have a laundry list of side effects yet not for X individual?"
] |
[
"Do electromagnets still have north and south poles? How is polarity in an electromagnet determined/changed?"
] | [
false
] | null | [
"Yes, they still have poles. The convention is the same: magnetic field lines point away from North poles and towards South poles.",
"You’ll often find electromagnets (superconducting or normal-conducting) with iron cores, and the iron is often shaped to create the desired shape of the magnetic field. These piece... | [
"The polarity is determined by the direction of current flow in the coil. Reversing the current reverses the poles. The ",
"right hand rule",
" is used to determine what direction of current is needed to make one specific pole north.",
"When wrapping the right hand around the solenoid with the fingers in the ... | [
"Follow up question, does the conventional north pole of an electromagnet have the same expected interaction with the north pole of a conventional magnet? Would they still repel each other or is there other things to consider? "
] |
[
"How is it so that several (all?) mammals grow and lose a set of \"baby teeth\" before growing their final dentition? Why stop at two sets when other vertebrates such as sharks regenerate their teeth constantly?"
] | [
false
] | null | [
"There are a handful of mammal species that constantly replace lost teeth, but most don't. On the flip side, quite a few non-mammals continuously replace lost teeth. ",
"There's two factors that seem to be at play in mammal tooth growth patterns. First, early mammals were probably relatively short-lived little... | [
"Evo devo guy here. This is basically the answer the tooth researchers I know tend to favor. There is some mechanistic trade-off between the development of specialized teeth and the ability to re-initiate tooth development later in life. ",
"I tend to think \"its a waste of energy\" (mentioned by other posters) i... | [
"Evolutionary developmental biology (informally, evo-devo) is a field of biological research that compares the developmental processes of different organisms to infer the ancestral relationships between them and how developmental processes evolved.",
"https://en.wikipedia.org/wiki/Evolutionary_developmental_biolo... |
[
"If a large object (e.g. car) was dropped in the middle of the ocean, what kind of waves would we see when they reach land?"
] | [
false
] | So my understanding about ocean waves is that they are mainly created by wind blowing out in the middle ocean in a certain direction, they keep traveling while building up, and eventually they reach land. Please correct me if I'm wrong. My question is if wind blowing out at sea can create some pretty big waves, what if a heavy object (car?) was dropped from say 30 feet into the ocean a few miles off of shore? Would the waves created keep carrying make some massive breaking waves on shore or will they die out without wind? | [
"I think to answer this question simply, you would have to paint an ideal scenario. The atmosphere is completely still and there are no thermal gradients or ocean currents. You drop a specific car at a specific height. If someone can model this that would be great.",
"In a real scenario there is not quantitative ... | [
"Bear in mind that waves would expand from your hypothetical car splash radially, so however much energy the car's hitting the water imparted would be spread out in ever expanding circles. So in the time the (ideally) circular wavefront had proceeded say 10 times farther out, that energy would also be spread round ... | [
"I'm not an expert in fluid dynamics, but I'm just going to guess that the volume if the ocean is just way too large for a car. \nIf you think about it, tsunamis, which sometimes aren't even that big, are caused by entire plate shifts under the ocean. "
] |
[
"Will secondary light colors (CMY) reflect *all* of the primary colors (RGB) in it completely, or only some?"
] | [
false
] | For example, I know that if I shine red light onto a red backdrop, of the red should be reflected and colors are absorbed in the background. But if I shine a red light onto a magenta or yellow background, will of that red light be reflected and will it appear just as bright red to me as it did on the red backdrop? As in, will it have the same contrast level? In other words, will yellow pigments, for example, reflect reds and greens completely, or only a portion of the green and red light? | [
"In reality, the way pigments work is such that they do not absorb and reflect perfectly. ",
"If you assume that you have ideal surfaces, a yellow surface will absorb all blue light and reflect all red and green light. A magenta surface will absorb all green light, and a cyan surface absorbs all red light. "
] | [
"Thanks. That is what i was thinking, but i couldn't find a straight answer."
] | [
"There are two kinds of colour that our eyes see. A pure spectral line has a single wavelength, which if it isn't red green or blue will stimulate more than one cone in the retina, and our brains interpret the mixed signal and assume it is that colour. So yellow light stimulates both red and green cones, as the con... |
[
"The moon rotates around its own axis at the same speed as its rotation around earth, which is why we don't see the \"dark side\". Is this purely coincidental or not?"
] | [
false
] | I'm sure there's a logical explanation I'm not seeing, or is my interpretationof "dark side wrong? (Thank you all for your many responses!) | [
"Before answering your question, I'd just like to point out that there is no permanently dark side of the moon. There is a far side of the moon, which never faces the earth, ",
"but it experiences a normal cycle of sunlight as the moon goes around.",
" During a full moon (as observed by humans), the far side of... | [
"Thank you for taking the time to reply! Fascinating!"
] | [
"As has been answered, it's not a coincidence. What is a coincidence is the fact that the sun is 400x the size of the moon, but also 400x as far away from the Earth as the moon, making the sun and moon appear to be approximately the same size in the sky."
] |
[
"Why do vaccines use mRNA? Why not just put the viral protein into the lipid nanoparticles instead?"
] | [
false
] | In the case of mRNA COVID vaccines, my understanding is they work by shutting mRNA into cells using lipid nanoparticles. Ribosomes then turn those mRNA instructions into a spike protein. Why don't vaccines just put the spike protein into the lipid nanoparticles instead? Wouldn't that trigger the same immune response? Why go to the extra trouble to get our own cells to synthesize the protein? | [
"In the process of translation within cells, where mRNA is translated into polypeptide chains (proteins), many copies of each protein are made simultaneously from a single copy of an mRNA. So, while a nanoparticle with a hundred copies of a protein would introduce just a hundred copies of that protein proteins, a n... | [
"If you use mRNA, each molecule of mRNA will be translated by the cell to many copies of the protein, so you get an amplification effect. The mRNA also gets recognized by pattern-recognition receptors that activate the innate immune system, which is necessary to start up the adaptive immune system. Protein in itsel... | [
"Vaccines that use protein exist. For COVID-19 that’s Nuvaxovid. It’s a perfectly workable solution. But mRNA offers certain benefits, two of which are:",
"First is manufacturability. To mass produce very pure protein is hard. It is typically done by transfecting some cells with DNA of the protein to produce, the... |
[
"At some point in the past, was the cosmic background radiation red shifted into the visible light spectrum?"
] | [
false
] | If we hypothetically existed during this time, would the entire universe illuminate a certain color? Blue first then very slowly becoming redder and redder until it was no longer in the visible light spectrum? Would the light be blindingly bright? Also I understand that the change from the blue side of the spectrum to red side would not occur during the lifetime of a human. | [
"The CMBR originates from the recombination era - a time around 380,000 years after the Big Bang. At this time, it had a temperature of around 2600 degC, so the light would be roughly similar in colour to that from a tungsten filament light bulb. It looks bright yellow, though well over half of the radiation spectr... | [
"It is thermal radiation, so it would never have been green. It would have changed in colour in exactly the same way as a hot glowing object changes as it cools."
] | [
"\"green\" is a pretty narrow range of wavelengths. A star's emission can peak in green wavelengths (in fact, the Sun does), but blackbody radiation is a broader spectrum than what we see as \"green\", and our definition of colors is defined over so narrow a space that a star that peaks in green wavelengths just lo... |
[
"What's the distance between atoms in a solid?"
] | [
false
] | Just wondering how close together atoms are together in a solid item or molecule. I know that electrons are far from the nucleus but say i have two atoms next to each other, are the nuclei seperated by the electrons or are the electrons just kind of interlocked and the nuclei next to eachother? | [
"Atoms are surrounded by electrons, yes, but only the outermost electrons participate in bonding.",
"Therefore yes, there is a \"wall\" of electrons between the nuclei of two atoms that are close to each other. (Meaning every electron that DOES NOT participate in bonding is still \"AROUND\" the individual atoms.)... | [
"This isn't a question that can be answered directly like \"atoms are 1 Angstrom apart\" because atoms are not balls. You can talk about the density or the average center to center distance for an atom, but in a solid, there is no empty space between the atoms. They are in contact.",
"Rather than trying to re... | [
"They are in contact, but we can give distances between their centers which is physically meaningful."
] |
[
"Is turning old paper into mulch and spreading it around trees better or worse than sending it to be recycled?"
] | [
false
] | In villages the people take old paper, put it in a bucket and leave it outside on rainy days. When it rains the paper turns into mulch. The villagers then take that and spread it around trees, mixing it with the dead leaf mulch. They believe it helps the compost, and judging from the quality of the trees and fruit they bear i can't say it has any visible negative effects. Is such a treatment better or worse than giving them away for recycling? I heard that unlike aluminum, where it's actually very profitable to recycle it, and glass, where it's marginally profitable, paper actually requires more energy to be properly recycled. Is that true? | [
"There is absolutely no bleach in paper after production is finished. Additionally, paper does not use chlorine bleach(which, by the way, is harmless after the reaction completes - saying bleach is bad because it contains Chlorine is like saying salt is bad because it contains Chlorine) they use hydrogen peroxide ... | [
"Not a direct answer to your question, but this mulching not be good practice as ",
"a whole load of chemicals",
" are used in the process of making the paper. Whether these will get into anything that you subsequently grow in the soil and eat and whether they are harmful to health I do not know."
] | [
"Newspapers use very safe inks (soybean oil and carbon black) and can be ",
"safely composted",
". This is potentially even a good idea because compost tends to run nitrogen-heavy and carbon-poor without sawdust or paper or something.",
"The brightly-colored latex-rich glossy advertisements once contained le... |
[
"Do black holes ever die?"
] | [
false
] | And if so, why and how? | [
"Ok. I'm seeing a lot of answers that are just missing the point so I'll say this straight.",
"Yes, Black Holes and Hawking Radiation are both Hypothetical. But per those hypotheses...",
"A black hole while being a region of the universe that no \"thing\" can escape from, Emits radiation on it's own at a temper... | [
"It's not total mass but density that determines if there is a region in which gravity is so great light cannot escape. In theory you can make microscopic black holes, but they would evaporate very quickly. There was [a silly debunked fringe] concern that firing up the LHC would create a black hole that instead of ... | [
"It's not total mass but density that determines if there is a region in which gravity is so great light cannot escape. In theory you can make microscopic black holes, but they would evaporate very quickly. There was [a silly debunked fringe] concern that firing up the LHC would create a black hole that instead of ... |
[
"Can life develop without a nearby star as an energy source?"
] | [
false
] | null | [
"I think this is only one answer, but the habitable zone doesn't necessarily have to be based within that very specific area around a star.",
"For example, there are geological processes that can create heat, or energy that life could develop with. Europa, a moon of Jupiter, has this going on as it is pulled agai... | [
"This is just a creative, theoretical idea I read about.",
"A couple of scientists at ",
"Fermilab",
", Dan Hooper and Jason Steffen, calculated that \"the dark matter that lies at the heart of the galaxy could heat an alien world enough to make it habitable.\"",
"There was an article about it in NewScienti... | [
"Dorian Abbot and Eric Switzer say they've calculated that rocky planets with a mass similar to that of Earth could stay warm enough to keep water liquid under thick, insulating ice sheets for more than a billion years.",
"Link"
] |
[
"How does scientist know the molecular structures of chemical compounds?"
] | [
false
] | null | [
"There are a lot of different analysis methods which give you information about a molecule, the most important ones are:",
"Mass spectronomy",
" gives you information about the mass of a molecule and possible even the exact number of different atoms",
"Elemental analysis",
": gives you information about the... | [
"^ this is the correct answer. Structure determination almost always involves multiple complimentary techniques, and a good chemist will know (or at least appreciate) them all. "
] | [
"I think you mean X-ray Crystalography? Though I might be wrong, but that matches your desciption better than the link.",
"X-ray crystalography works using diffraction - when light goes through a gap of a similar width to its wavelength, it will spread out, like a knew source of light... the end effect is, if you... |
[
"Can you measure mass without acceleration?"
] | [
false
] | A kilogram is a measure of mass. On earth we weigh it with a scale, and in space we might try to accelerate an object and see how much force it takes. If for whatever reason we couldn't accelerate it, is there a way to measure it's mass? Also, now that I think about it, does this mean a person would technically be however many kilograms on earth or Mars, because if the definition? | [
"It's an interesting question, I think you cannot directly measure mass without somehow using acceleration (even indirectly), as mass is a \"measure of inertia\" so to speak, and you can only measure inertia accelerating the object. (EDIT: I was thinking Newtonianly only!!)",
"If you know some properties of the m... | [
"1) take a large amount of antimatter, place it in a box ",
"2) ",
" place the object of unknown mass in the box (safety goggles are a must!)",
"3) examine the damage done to the solar system, use this to extrapolate the amount of energy released",
"4) simply convert that energy to mass using e=mc"
] | [
"force=mass*velocity",
"No. Force=mass x acceleration. Mass x velocity is momentum.",
"This may have been a careless mistake, but in case it wasn't I felt the need to point it out. "
] |
[
"Why do toxicology tests take so long?"
] | [
false
] | I hear it in news stories constantly. People who have killed themselves, violent offenders like the Miami face eater, et cetera. The toxicology report will take two weeks, three weeks, four weeks. Is it a matter of the lab being backed up with tests, or is their an actual test that takes weeks to conduct? I always thought drug tests were just an analysis of the emission spectrums of whatever drug they are looking for. | [
"Imnunoassay development scientist here. One correction, immunoassays do not test for antibodies in the blood against toxins or drugs, they use antibodies in the assay to bind the molecule of interest itself. ",
"Think of it this way, testing for antibodies to a substance suspected of causing death in a person is... | [
"Cool, never thought I'd come across an immunoassay developer. What types (as in RIA/EMIT/CLIA/etc) do you develop? Or do you primarily develop the antibodies? Oh, and I've wondered why it seems like surface plasmon resonance has less adoption in clinical labs than I'd otherwise expect- it seems like it would be si... | [
"In addition, it is not likely that a single lab could test for all of these chemicals because doing such would require an enormous facility with a large number of different machines and specialized technicians. Thus it's easier for there to be numerous specialized labs that may be required for testing.",
"This i... |
[
"What's the estimated amount of time for distant galaxies to start disappearing due to the expansion of the universe?"
] | [
false
] | And would this be definitive proof of an unavoidable "big rip"? | [
"100 billion years"
] | [
"For about the next 2.7 billion years, more and more galaxies will become visible as the light from them reaches us. After that, it will all start to slowly go dark as everything else is too far away for the light to EVER reach us, and the visible universes red shift into obscurity.",
"edit: said universes when I... | [
"more and more universes will become visible ",
"I would love to see a source for this one."
] |
[
"AskScience AMA Series: We are working to build precise atomic clocks that could fit inside your smartphone. Ask Us Anything!"
] | [
false
] | Atomic clocks are among the most precise scientific instruments ever made, and play an important role in advanced navigation, secure communication, and radar technology. Kyriakos Porfyrakis and Edward Laird of the University of Oxford are working on building a hyperprecise atomic clock that could fit on a chip inside a smartphone. They begin with a nitrogen atom, which resonates at a particular frequency and acts as a very precise reference point by which to track time. Since nitrogen is highly reactive, they have to trap the nitrogen atom inside of an endohedral fullerene-a sort of atomic cage made out of 60 carbon atoms-in their lab. To do it, they used a process called ion implantation. This process produces a molecule called N@C_60 that can easily be collected and stored (they even sell it for £200 million per gram). But before they could put the molecule in a clock, they also had to figure out how to cancel out magnetic fields from the surrounding environment that could disrupt the energy level of the nitrogen atom within. Earlier this year, they developed a way to shield the nitrogen atom from external magnetic fields by applying a steady magnetic field that would cancel out any effects. They recently wrote about their work for IEEE Spectrum ( ). They'll be here starting 12 PM ET (17 UT). You can ask them about GPS, atomic clocks, nanomaterials, or anything else! | [
"The main advantage of timekeeping technology for smartphones is that any stable clock is also a precise frequency reference. In smartphones, the advantages are mainly for radio communication and for navigation via the global positioning system (GPS).\nImagine that your smartphone is trying to download a document o... | [
"Why? What benefit would this serve my phone?"
] | [
"isn't it easier to just sync smartphones to a single atomic clock for daily reference?"
] |
[
"What makes Cancer so difficult to find a cure for? How far have we gotten and how far have we yet to go to find one?"
] | [
false
] | [deleted] | [
"Cancer by itself is a misleading term. It is not a single disease, but rather a group of diseases resulting from the consequence of a derangement of the cell cycle. In a normal cell there are phases of growth, each tightly regulated by biochemical feedback mechanisms. When that regulation breaks down and the growt... | [
"To add on to baloo's very thorough answer, this is why whenever you hear someone talk about a conspiracy to hide a \"cure for cancer\" or some such thing, you can know they have no idea what they're talking about. There can be no single treatment that can cure all forms of cancer, since cancer isn't a single thing... | [
"People have explained why it's hard to find a cure for \"cancer\". What seems to be poorly appreciated is how much improvement there has been in the past 30-40 years. ",
"Treatment of childhood cancers in particular has improved enormously. Cancers that were nearly death sentences 40 years ago are often nearly 1... |
[
"If you could get to the centre of a black hole, would you just freeze in time?"
] | [
false
] | Or do you exit out of a white hole or something? | [
"Here",
" is RobotRollCall's comment on that topic which you might enjoy reading.",
"Also, BH questions come up fairly regularly here, so there is a wealth of knowledge on the topic in the ",
"/r/AskScience",
" ",
"search archive",
". "
] | [
"you hit the surface and were pancaked into a roughly \"you\" shaped smear",
"Years of cartoons have allowed me to picture that image perfectly."
] | [
"Very informative post from someone obviously much more informed than I am. And also eloquent. thank you kindly!"
] |
[
"Is the idea that women synchronise their periods a myth?"
] | [
false
] | I was having a conversation with a couple of girl friends yesterday who were saying how when they go back home they often synch their periods to their family members, I have always assumed that this phenomenon is a myth because I cannot think of a single productive reason why it would happen. Is there any science behind it? | [
"There is conflicting evidence. McClintock was a psychologist back in the 60's and 70's. She did a study back then which suggested synchronization but subsequent studies with lesbian couples conflict with her findings. As for the science behind it, I'd assume pheromones. "
] | [
"Just to clarify - the last \"famous\" McClintock study related to this was in 1998 - wherein she exposed participants to swabs from the secretions (underarm if I recall) of other women over several weeks.",
"According to the study, \"It is likely that menstrual synchrony is part of a larger phenomenon of social ... | [
"Do Women Who Live Together Menstruate Together?",
" (Scientific American)",
"McClintock is still actively researching the area. The most important questions, she says, are exploring the underlying mechanisms behind variation in the social effects on ovulation: Why do some women not respond? Why are some phases... |
[
"If light is photons, what happens to a photon after it's spent its energy?"
] | [
false
] | Not sure if I'm understanding this correctly, here goes. When a candle shines in a dark room, we see a halo of light, surrounded by darkness. The photons that leave the candle are traveling outward from it in all directions, as far as I understand. What actually happens to the photon when it travels from its 'lit' state to its 'dark' state? Does it just disappear? Does it become something different? Thanks for any input! | [
"It sounds like the energy changes its label.. ",
"I like the way you put it. ",
"what does it become if no longer a photon? ",
"It stops existing. Just like the flame of the candle stops being a flame when someone blows it out. ",
"In some sense, the photon is a representation of an interaction, rathe... | [
"Yes, it disappears. Its energy continues to exist, but the photon is gone. "
] | [
"Imagine throwing a ball straight upwards. The ball slows down, and at one instance actually stops. Where did the kinetic energy go? It became gravitational potential.",
"Same thing with photons. When it is absorbed by an electron (for example), the electron gains energy."
] |
[
"Why did scientists like Slotin and Daghlian do their criticality experiments manually?"
] | [
false
] | I was reading about the , and I was wondering why the two scientists involved ever attempted to do their experiments manually? Maybe I'm just being a wimp, but I would think of anyone on the planet, Slotin and Daghlian would know best how dangerous that was. I understand that a remote system for doing these experiments was built after the second incident. Is there a reason this wasn't developed and used earlier? | [
"From what I read, during the war, time was the problem. They didn't have time to engineer a remote automated system to do it. By the time of Slotin's accident, May 21, 1946, there was no reason to do it manually. The war was over almost a year and the cold war had not yet begun. They said Slotin was just a daredev... | [
"The surrender of Japan was significantly more drawn out than the surrender of Germany.",
"The Japanese broadcast their surrender on the 15th but intermittent conflict occurred for several days afterwards. The last American serviceman to die in action was killed on the 18th. American troops would not land in Japa... | [
"You might find this serie of articles interesting too:\n",
"http://blogs.sciencemag.org/pipeline/?s=things+I+won%27t+work+with",
"this has many example of chemists taking unnecessary risks, as well as a long long list of terrifying experimental setups. Some people just seem prone to risk taking, even when they... |
[
"If angiosperms (flower bearing plants) are so much more efficient than gymnosperms (non-flower bearing plants) at long distance dispersal and sexual reproduction, how come gymnosperms still exist everywhere?"
] | [
false
] | null | [
"to build on ",
"u/juandh",
"'s comment, you might take the analogy:",
"If priuses are more gas-efficient than other cars, why doesn't everyone drive a prius?",
"A pretty crude way to phrase the question, but it does give you insight into the same phenomenon. Efficiency certainly won't eliminate those that... | [
"An evolutionary disadvantage does not automatically lead to extinction. One species, genus, whatever may not be as evolutionarily fit as another, yet it may still manage to survive and even thrive.",
"There may also be certain trade-offs of a trait, meaning that no one species is dominant in every environment."
... | [
"You also have to think of the angiosperms in the context of the ecosystem. If the fruit tree is on a cliff, who's going to eat the fruit to spread the seed? ",
"If the animals that the angiosperm requires to make the seed dispersal don't traverse the rugged cliff side, how would the seed get there in the first... |
[
"so what if scientist figure out there was or/is life on mars?"
] | [
false
] | null | [
"Some things are interesting in their own right without leading on to anything else. Knowledge for the sake of knowledge.",
"However, at the moment we have only one data point for the existence of life in the universe. Life on Mars would be evidence that Earth isn't a fluke and suggest a greater chance of finding... | [
"Treatid is correct. How the life is structured will mean so much to us. If it uses DNA then there is a good chance that it might be related to life on earth. If it happens to be the left-handed, double-stranded helix formation that our DNA is then we'd have to seriously reconsider the origins of life here on earth... | [
"ahh that is interesting. Now i am excited lol. I hope they do find something...",
"On that note, how big does an asteroid have to be, to make pieces fly from earth to mars!....Assuming for discussion purposes, lets say that did happen. Wouldn't the organism die during the travel through space??"
] |
[
"How do satellites focus on different obejects?"
] | [
false
] | Do they use thrusters to change/keep the view? | [
"If you're talking about the stereotypical spy satellite with cameras, the satellite itself usually doesn't move other than to stabilize or correct its orbit. The camera is gimbaled, allowing it to tilt and swivel. So it can track the focal point on the earth, and at the altitude it's at a simple 1° tilt can move t... | [
"Oh if you're talking about looking out from a planet that's a whole different story, but no they don't often change the orbit of satellites. See, holding a satellite in one stationary point would take an enormous amount of fuel while maintaining an orbit costs little to no fuel at all.",
"It's important to remem... | [
"It's extremely expensive to use thrusters to \"retask\" a satellite because they have a very limited amount of fuel. It's not to say it never happens, but it would have to be something very important.",
"In general, they just try to have enough satellites whizzing around orbiting the Earth that one is likely to... |
[
"Is it possible to make it all the way around the crossbar on a swing set?"
] | [
false
] | null | [
"on ",
"one of these",
", yes!"
] | [
"Ah! Now the distinction here is that the arms are rigid. The rider can use them to keep herself at a constant radius. On a normal swing set, the arms are chains (usually), and will collapse at above horizontal. "
] | [
"If you mean by having a person push or 'pumping' with your legs on a traditional (chain or rope, nonrigid) swing, no. When you get to a point close to horizontal chains, you'll notice the swing skips a bit at the peak. You come out of the seat for a second while you change direction. That skip costs you some of yo... |
[
"Is mRNA stored in our cells? Do we have a reserve if lets say RNA polymerase II stops working?"
] | [
false
] | null | [
"No. The levels of a specific mRNA are tightly regulated, on the side of its synthesis as well as on the side of its degradation. There are no stores of \"excess\" mRNA, it's constantly dynamically regulated to the necessary amount."
] | [
"Well could u help me determine the reason for why alfa-amanitin has a ”slow death”?"
] | [
"It's not a total inhibitor. It just slows down the RNA polymerase II. See for example ",
"Rudd, 1996",
". It thus takes a while until things fully get out of whack."
] |
[
"Do Freud's teachings/ideas have any relevance anymore? If not, why are we still being taught them?"
] | [
false
] | null | [
"TL;DR No, it's better considered as history and not current science, and it's still taught because 1) Intro Psych professors don't like updating their courses 2) there's a legacy of psychoanalysis that's still influencing practice, especially in the APA.",
"Here's the longer story. First, we should separate Freu... | [
"Only one of those studies in that meta-analysis you cited was an RCT, and most of their measures are pre-post measures. Entirely susceptible to regression to the mean, historical effects or any number of other problems. This is the problem with psychoanalysis, the quality of the research is shockingly poor relativ... | [
"I am not a scientist, but I do work in the fields of English/Philosophy/History, and can give you a perspective from the \"liberal arts\" side. I hope that I am forgiven as I do not mean to intrude upon the science sphere, but I think I have some information relevant to the OP's question.",
"Though most scienti... |
[
"What are the units after integrating dx/x?"
] | [
false
] | Hello all, An interesting issue came up: I have the following differential equation: dF/dm == F/(k T) Now F has units J/cm m has units J, and k T has units of J, so the original problem satisfies dimensional analysis. But what about when you integrate? You get ln(F) = m/(k T), but that is dimensionally inconsistent! Where did the units inside the log go? If it's something like ln(F)+C then does any C work or is it arbitrary? and if C is arbitrary, then what's the significance of the equation? I feel like I'm missing something fundamental about the calculus... | [
"Taking a dimensionless number to the power of something with dimension is non-sensical.",
"Taking ",
" quantity to the power of a dimensioned quantity is non-sensical."
] | [
"What you're missing here is that dF has the same dimensions as F. In other words, the differential of a quantity has the same dimensions as the quantity itself.",
"Think of this in terms of length ",
". ",
" is just a difference between two lengths, x(n+delta)-x(n), so it still has dimensions of length.",
... | [
"Right. I agree with everything you've said.",
"But, in wolfram language: Int[F",
" F] evaluates to Log[F]. If F has units of, say, J/cm",
" then the integral is indeed dimensionless, but evaluates to something that is the log of a dimensioned quantity. The problem here isn't that Log[F] needs dimensions. ... |
[
"If earth's mountains are formed by shifting tectonic plates, are mountains on Mars formed by the same process?"
] | [
false
] | null | [
"Here's a great video from a NASA employee",
" that outlines the various processes that form mountains on Mars. In short, no, there is no evidence for plate tectonics on mars. The mountains are caused by impact events, and occasionally by volcanism--which can occur without a plate tectonic system, similar to Hawa... | [
"I find it really troubling An Yin says \"the evidence is quite clear\". Not that his evidence isn't important to consider, but he has no business (IMO) proclaiming it with such a degree of certainty. It just reeks of overzealous self-promotion without any acknowledgement of the complexity of the issue that others... | [
"In short, no, there is no evidence for plate tectonics on Mars.",
"Might I draw your attention to ",
"this",
" image and ",
"this",
" article from 2012 regarding evidence for tectonic activity on ancient Mars. I'm having difficulty locating the original paper to which the article refers, but to quote An ... |
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