title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How come we can create a 2D picture of IR, visible light, UV and X-ray but we can't create a 2D picture out of radio waves for example?"
] | [
false
] | [deleted] | [
"You can, it's called ",
". The spatial resolution is determined by the wavelength of the radio waves so can vary from centimeters to 10s of meters. Also, radio waves penetrate/reflect from objects differently from light waves so you 'see' different types of things. It's possible to use radio tomography to 'see... | [
"The airforce does this with planes that they want to be difficult to detect on radar before they go out on missions to verify that they won't be detected.",
"Here is an image of a car using radar.\n",
"http://www.sysplan.com/images_content/radar/capabilites/gpu/gpu_saab.jpg"
] | [
"It depends on what you mean by \"creating a picture\".",
"The reason why \"taking a picture\" in the traditional sense doesn't work for radiowaves is that their wavelength is around 1m, so you cannot resolve objects smaller than that (very roughly speaking). This does work just fine for radioastronomy, where the... |
[
"If you were landing on an alien planet and your instrumentation died on approach, would it be visually impossible to spot your altitude do to geologists fractal nature?"
] | [
false
] | null | [
"read the instructions in the comment..."
] | [
"Hi CaptainJamesTWoods thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of ... | [
"How do I add flair n mobile?"
] |
[
"Since direct current can be positive, negative or off, why not design logic circuits that use base 3 instead of binary?"
] | [
false
] | My kid has been learning about different number systems and it got me to thinking. | [
"Increased complexity of design and larger component footprints within the ICs. Positive/off systems or negative/off (where 'negative' current is really just positive current with a different assumption made about it) systems are nice and easy because your digital inputs for whatever makes up your logic gates only... | [
"Great question. This is known as ",
"balanced ternary",
". To be honest I can't give you an answer beyond the standard \"ternary is more complex than binary\". The fundamental unit of transistors is the diode, which is designed to work in a single direction of current. Off the top of my head I'm not sure how y... | [
"Edit: See byrel for corrections to what I said.",
"Some circuits do use three values, but one value is a \"Don't care\" value. In content addressable memory (as opposed to your normal random-access memory), you can retrieve values that satisfy a string of 1's,0's, and \"x\"'s, where the x means it can be either ... |
[
"Do humans ears \"pop\" if they are aboard a diving submarine?"
] | [
false
] | [deleted] | [
"No. When flying the cabin isn't airtight, and at 30k feet atmospheric pressure drops inside the cabin to a pressure roughly equivalent to 6-8k feet above sea level. This change in effective pressure in the cabin causes ears to pop. ",
"When diving in a submarine the sub is watertight and there is the same amount... | [
"It's basically the exact same pressure at depth. There's an immense amount of steel structure on the interior of a submarine, typically in bulkheads. If there was any compression of the inner hull it would be unevenly distributed due to the bulkheads, and significantly uneven distribution of water pressure at dept... | [
"Are you sure it's the exact same pressure at max dive depth? I thought the water pressure would squeeze the sub a bit. Not crush but squeeze. Maybe not enough for ear popping though. "
] |
[
"How does UV light kill bacteria?"
] | [
false
] | null | [
"UV photons have enough energy to break chemical bonds. When UV light hits a bacteria it breaks bonds randomly. The resulting broken molecules are unstable and may further damage other molecules. This results in damage to DNA and RNA and broken or malfunctioning proteins. The bacteria can repair itself if there is ... | [
"Other replies to this thread are sort of true, but miss the main answer. UVA/UVB light generally isn't powerful enough to ionize atoms and break bonds (at least for the types of bonds present in biomolecules), but it does excite certain bonds and make them reactive. When pyrimidines in DNA get excited, they form "... | [
"I always thought cyclobutane T-T dimers were caused by ionization",
"It's a photochemical [2 + 2] cycloaddition, if you want to get into the mechanistic details. Interestingly, this reaction is reversible in presence of the repair enzyme photolyase.",
"There are also other forms of DNA photoadducts, which are ... |
[
"What does the evolutionary timeline of the platypus look like?"
] | [
false
] | Every feature about them seems to be taken from other species. 10 sex chromosomes similar to birds, eyes like hagfish, feet/bill like a duck, beaver tail, one of the only mammals to lay eggs, sweats milk instead of having nipples, has venom, electroreceptors like a shark, etc etc.. It seems like nature just clicked the... | [
"Platypi are (probably) more closely related to birds than any other mammal",
"This is really misleading. I'm aware that ",
"this article",
" says that the platypus' possession of a sex chromosome which is homologous to one of those present in birds suggests that, from their abstract,",
"\"This suggests an ... | [
"Platypi are (probably) more closely related to birds than any other mammal",
"This is really misleading. I'm aware that ",
"this article",
" says that the platypus' possession of a sex chromosome which is homologous to one of those present in birds suggests that, from their abstract,",
"\"This suggests an ... | [
"Monotremes (the Platypus and the Echidna are the only examples I know of) shared a common ancestor with other mammals about 160 million years ago. We can call them our extremely distant cousins (actually, the most distant mammal cousin). "
] |
[
"Do dietary studies normally include the calories of what's leaving the body?"
] | [
false
] | There are tons of dietary studies presented to us every day. Quite often there are contradictions, which leads to the question: Are calories in urine, feces etc. measured and subtracted from the intake in dietary studies? | [
"It depends on the kind of study, sometimes they do.",
"http://ajcn.nutrition.org/content/94/1/58.long",
"No significant difference was shown in energy excretion in stools between lean and obese subjects who consumed the 2400-kcal/d diet [134.3 ± 48.9 kcal/d (lean) compared with 133.2 ± 44.8 kcal/d (obese) (P =... | [
"Short answer: No, they are not.",
"The body should not be shedding calories in the urine. There is caloric content in feces, but it wouldn't be easily quantifiable. If you really wanted to be precise, you would have to separate bioavailable calorie sources from biologically unavailable calorie sources. Every ... | [
"This is done by the release of heat from the body",
"Actually it's done by the release of CO2 from the body. Fatty acids are around 80% carbon by weight, so when you lose weight, it's because your body literally burned some fat, i.e., converted hydrocarbon chains to CO2. A 140 lb person exhales about 1 kg of CO2... |
[
"Do gaseous weight figures usually take in account their buoyancy?"
] | [
false
] | Just watching a SciSchow clip that mentions astronauts on ISS consumes only 840 grams of O2 a day, and I imagined how gases can be weighed, then wondered if all those metric tons of CO2 figures take in account their buoyancy when the samples were measured... | [
"840 grams is a mass. It doesn't depend on buoyancy, or gravity, or anything. You can translate 840 grams to a number of O2 molecules. Same for tonnes of CO2. If you would want to put them on a scale you'll have to take buoyancy into account, but no one measures emissions by putting them on a scale - you measure th... | [
"No they don't take buoyancy into account. Buoyancy varies based on fluid and depth. Mass of gasses refers to the molecular mass. O2 is about 32 g/mol. A mol is a specific amount of atoms (6.022 x 10",
" So in your example they're saying the astronauts breathe 26.25 moles of O2 a day."
] | [
"I don’t believe they do. Although I’d like to offer an interesting comment. In scuba diving, a full tank weighs more than an empty tank. If you are diving with a standard aluminum tank as opposed to a steel tank, you have to take buoyancy into account as empty aluminum tanks will actually float."
] |
[
"How is water collected?"
] | [
false
] | How is water extracted from Oceans and Seas on industrial scales? Or maybe what's the term used for that sort of thing so I can look it up? I wanted to learn about the potential impacts of this behaviour on the environment. | [
"If you're talking about potable water used for drinking, nearly all of it comes from freshwater sources (surface waters, underground reservoirs). A typical flow diagram for water collection starting from the source and going through a water treatment plant and then to a home or business looks like this",
"http:/... | [
"It uses the reverse osmosis process. Osmosis is the net movement of water from high water potential to low water potential through a semi-permeable membrane. ",
"Basically, you \"push\" (insert pressure) the salt water through a barrier where it is semi-permeable (only water can pass through, salt can't because ... | [
"Not really. It's cheaper to use reverse osmosis. However, look up waste heat desalination. Basically uses the heat put off from power plants to boil off and condense water (there's been a lot of research put into utilizing this for small scale generators that could help in the event of a natural disaster)"
] |
[
"When whales and other aquatic animals come out of the water, does their eyesight become blurry like ours do going into the water? How do amphibious animals handle seeing in and out of water?"
] | [
false
] | I saw a video the other day of a whale poking it's eye out of the water to get a better look at a boat and it got me to wondering would it make their sight blurry. | [
"Ok, it bothered me so I had to check. Whales have a great eyesight in the water contrary to what was long believed. Even dolphins who use echolocation have good eyesight. \nWhen they come out of the water they get nearsighted but correct it with very strong muscles to bend the cornea. I'm only repeating what I rea... | [
"That is an excellent question... I have divergent answers on the net. Some say that it's probable that crocodiles don't smell under water since they close their nostrils, others say that they have olfactory bulbs specially modified. But I don't know how. ",
"However, it seems that they can taste water since they... | [
"How do non-water-breathing animals detect smells in water?"
] |
[
"By what mechanism is a human being able to estimate the passing of time? What happens when this function is disrupted? Can you lose your sense of time passing?"
] | [
false
] | [deleted] | [
"Just to expand. ",
"Tests have been done showing people in rooms with no time-based environmental cues having significantly inaccurate estimations of time passed. There have been some pretty crazy stories on this subject.",
"Lowered states of consciousness (e.g. Meditation, concussion, sleeping, coma) are also... | [
"I think OP between the lines asks an interesting question not asked a lot: what areas in our brain handles time? ",
"How do the areas change when faced with a clock in a doctor's room, or a clock when late for a buss. What areas activate when the brain handles \"time\" and what does it mean cognitively? "
] | [
"Human beings often sense the passage of time via such things as the rotation of the earth around its axis, and the rotation of the earth around the sun (indicated by the amount of sun or starlight visible in the sky, or by the changing of the seasons); as well as watches, and digital or analog clocks.",
"A human... |
[
"How many people would there need to be for a good (P>.5) chance that an arbitrarily selected person to have a perfect genetic match?"
] | [
false
] | null | [
"Ok. So, basically, every time I try to figure out how to answer this question, I just circle back around to \"yeah, basically not possible\". Two randomly chosen individuals will differ at approximately one out of every thousand sites. There are 6 billion sites in the human genome, so that means we expect a random... | [
"If you look at the Poisson equation, for X=0 it just comes out to e",
" For λ = 6 million, that's about 10",
" .",
"Realistically it's much higher than that, since people who are related have vastly fewer differences, and some people are even identical twins. Even then, I think you're probably not a perfect ... | [
"What exactly do you mean for a person to have a genetic match?"
] |
[
"What are physiological tricks of the human body?"
] | [
false
] | null | [
"Not sure how to add the flair"
] | [
"Not sure how to add the flair"
] | [
"This question is too broad/ vague."
] |
[
"Why do my LED lights change color near my hotplate?"
] | [
false
] | null | [
"LEDs are based on semiconductors which are sensitive to their environment. Semiconductors have something called a bandgap which is the origin of the emitted light. By altering the bandgap the wavelength (color) of the light changes. Not sure about the details of your exact situation but it's possible the heat caus... | [
"This is fascinating--a little research shows that AlGaInP is used in the manufacture of both orange and \"traditional green\" wavelength LEDs. My old lab chief described semiconductor doping and manufacture as some arcane wizardry, as far as sensitivity to conditions goes; I wouldn't be surprised if you melted som... | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"If you disagree with this decision, please send a message to the moderators."
] |
[
"Why doesn't malaria spread from endemic to non-endemic regions of the world?"
] | [
false
] | [deleted] | [
"Malaria parasites can’t complete their life cycle in mosquitoes if the temperature falls below about 20 oC (68 oF). That means that in temperate climates, malaria spread is seasonal and inefficient. ",
"Malaria once was common in the US, not all that long ago. The precursor of the CDC was formed to eliminate mal... | [
"The same strategy keeps Dengue fever, Chikungunya, and yellow fever in check."
] | [
"Malaria was common in the UK or at least believed to the cause of marsh fever. ",
"link",
" ",
"When I have traveled from endemic countries to non endemic by plans they sprayed insecticide in the plane before take off. ",
"There are concerns that with global warming it could spread further around the globe... |
[
"Are human feet any more thermosensitive than human hands?"
] | [
false
] | When you submerge your feet in hot bath water, it can sting a lot more than if you just put your hand in. Probably observer bias but worth an ask. | [
"So there's a lot of stuff to cover with this. First of all, the stinging you mention, is it just the normal sting of hot water touching your skin (that is at a normal temperature)? Or are you inadvertently referring to the stinging that comes from having cold feet (or cold skin in general) touching something warm/... | [
"Fantastic reply. I never factored the differing temperatures of feet and hands into this, but it makes a lot of sense.",
"Thank you."
] | [
"I'm glad I could help."
] |
[
"How do stock markets and equity sales benefit a company after the initial offering?"
] | [
false
] | So after a public company either has its initial offering or if they float more shares, how do the seconday market sales affect the company? The answer could very well be that it doesn't, but I just wanted an overview of the effects of secondary sales. Thanks! | [
"The company only receives money from the IPO or when they create more shares later. However, secondary sales do affect the company in a couple ways. ",
"Since the shareholders are the ones who get to vote in the company, someone completely outside the company could buy up a large chunk of shares and suddenly h... | [
"Many people working within the company, including low & mid-level people, take part of their pay in stock or stock options. It's an incentive for workers to positively contribute to the company. The higher a company's stock price, the more the employees make."
] | [
"A stock market provides shareholders with liquidity as they can convert their shares into cash.\nFor companies, a stock market gives them ability to raise funds from a larger number of investors in the future through methods such as rights issue "
] |
[
"How much electricity is saved during a widespread blackout like this?"
] | [
false
] | [deleted] | [
"The average person in the US uses 12,914kWh of electricity per year or 35.4kWh/day. This includes commercial and industrial use - let's assume that in blackout areas 5% of what is normally used is still going on through places with backup power. The latest news article I read said 8 million people were without pow... | [
"Is there a good way to estimate the extra power that will be used for the rescue/recovery/clean-up efforts? Because in my mind (with no experience or sources, so intuition) these would almost balance out. "
] | [
"Holy crap! Thanks for the info. ",
"Is this electricity just not being consumed, is it being stored, is it being wasted? "
] |
[
"What is the most common colour in the universe?"
] | [
false
] | To Clarify; Mean, Median and Mode. | [
"The most common photon in our universe are the photons from the cosmic microwave background radiation which is the afterglow from the big bang. These photons wave a wavelength of around 1 mm which our eyes cannot see. Check out Fig. 4 of this paper,",
"https://arxiv.org/abs/1004.2049",
"However, if you're inte... | [
"Correct me if I'm wrong, but given that any colour is derived from light, and black is the absence of that, is black a colour or just an absence? It's a pedantic question, but scientifically is it a colour?"
] | [
"black objects are objects that tend to absorb all visible wavelengths of light.",
"red objects are objects that tend to absorb all wavelengths but red, or at least absorb enough of other colors to make it reflect mainly red.",
"but neither refer to photons per se, they refer to how certain objects interact wit... |
[
"Is \"the urge to have children\" (AKA \"the biological clock\") partially inherent in people or completely socially constructed?"
] | [
false
] | null | [
"Please see research by ",
"Kristin Park",
". Childlessness is deviant from social norms; therefore, there is at least clear social pressure to reproduce. I'm not sure if anyone has done a study on your exact question, but the research shows that having children is a socially constructed activity."
] | [
"I have removed most responses for being speculation. If no one has a study to cite, then perhaps we can conclude for the time being that \"we don't know\" and this discussion can be resumed in ",
"/r/asksciencediscussion",
", our new-ish sister-sub, which is more focused on speculative and open-ended questions... | [
"The \"ticking biological clock\" refers to the decline in a healthy and normal pregnancy, which occurs naturally as we age; people who want to have kids, or who ",
" want to have kids are essentially racing against that timeframe before things start going wrong."
] |
[
"Why and when did certain natural human functions become something that requires privacy?"
] | [
false
] | null | [
"In some cultures where children share a common domicile with their parents, it is indeed common for parents to have sex in the vicinity of their children. Historically it was also normal to engage in sex during the period of wakefulness late at night (between the \"first sleep\" and the \"second sleep\").",
"Rep... | [
"The major source for the universality of biphasic sleep appears to be Roger Ekirch, according to whom it was normal in pre-industrial societies for humans to sleep first for four hours following sundown, enjoy an hour or two of wakefulness, then sleep for another few hours until sunrise, with a nap or siesta durin... | [
"Can you give more info on first and second sleep? It sounds fascinating."
] |
[
"Does being immune to a similar disease help the immune response to a novel strain?"
] | [
false
] | For example, even though most of us had the flu at some point, we are still at risk to get it again every year (or we have to get vaccinated again). This is because the virus has mutated enough that the immune system does not immediately recognize it & know how to deal with it. My question is, does a person who is immu... | [
"Milkmaids during the smallpox epidemic were found to be immune, having already contracted the weaker variant, cowpox. The immune system is a surprisingly good adaptive system, it just needs something to go on first. This is why we vaccinate as well."
] | [
"There really are not strains of SARS-CoV-2 yet. (I know there’s a paper that claims there are, but it’s nonsense.). We don’t know, of course, but the guess is that SARS-CoV-2 will change much more slowly than flu, so a vaccine (or immunity to a virus) should last for many years, with luck. ",
"Strains of influen... | [
"Influenza may seem like a similar disease, but the viruses are completely dissimilar. We wouldn’t expect any crossover immunity from influenza to SARS-CoV-2. ",
"What about from one strain of influenza to another, or from one strain of SARS-CoV-2 to another?"
] |
[
"How do electric guitars transmit sound?"
] | [
false
] | [deleted] | [
"Let's overly simplify the situation. The metal wire of the guitar attracts a magnet. This magnet is inside of a pickup coil of wire. As the wire vibrates up and down, the magnet vibrates up and down. As the magnet vibrates up and down it generates a current in the pickup coil. ",
"That current is then passed thr... | [
"I'm not precisely sure here. If I'm not mistaken though, each magnet/pickup configuration has a kind of natural frequency it would prefer to vibrate at, so it responds to those frequencies a bit better. Supposedly this was one of Hendrix's great inventions: that he played left handed, but did it by restringing the... | [
"That's extremely interesting! Thank you for the answer. As a follow-up, how does having humbuckers (dual pickups) differ from having single pickups?"
] |
[
"Is it possible that our solar system is inside of the event horizon of a black hole?"
] | [
false
] | From what I understand an observer out side of a black hole looking in on an object moving towards one will appear stretched to infinity, but that to the observer moving into the black hole the rest of the universe appears normal. Is it possible that the observable universe is really the event horizon of a large black ... | [
"This write up seems to refute the idea - ",
"relevant post by robot roll call"
] | [
"http://discovermagazine.com/2011/jun/03-our-universe-may-be-a-giant-hologram"
] | [
"http://discovermagazine.com/2011/jun/03-our-universe-may-be-a-giant-hologram"
] |
[
"Is it necessary for some people to use their vocal chords while sneezing?"
] | [
false
] | [deleted] | [
"The vocal 'cords' are in the path of a sneeze, and some people have more control over them than others. From a respiratory standpoint, all I can say is that anytime air is able to go through the vocal folds, they can change the sound coming out. This is why anyone with a (unfenestrated) tracheostomy is unable to s... | [
"I'm one of those loud sneezers. I can control the sound, but it requires effort and when I do the sneeze doesn't feel as satisfying as with it. So I don't. It's all about feeling good :)"
] | [
"My father does this loud sneeze. It's more like a shout.\nI have developed this same habit over the years. But I can control it, shouting or not.\nThe louder version clears throat much better and it feels better afters.\nbtw, I have to force the low noise sneeze, but the shouting version comes naturally."
] |
[
"Why is gallium never used by robbers?"
] | [
false
] | null | [
"Chemistry"
] | [
"Chemistry"
] | [
"or perhaps psychology?"
] |
[
"How do chimpanzees develop so much muscle on a diet of mostly fruit?"
] | [
false
] | null | [
"More than that, about ",
"half of chimpanzee diet are one fruit–Figs",
".",
"Actually, the chimp diet is very broad. About 97% of their food are plant sources (about 102 species, probably triple what a human consumes). But they also consume meat (usually other apes) and insects.",
"With such a broad diet, ... | [
"Chimpanzees work as a teams to chase other primates into ambushes, where they then kill and eat them."
] | [
"They don't eat other apes, though they eat other primates. The only other non-chimp apes that chimpanzees are known to coreside with are humans and gorillas. Chimps don't eat chimps, humans or gorillas - instances of cannibalism are very rare indeed.",
"They do eat a lot of red/ black and white colobus monkeys (... |
[
"Is heating/boiling water more efficient in a microwave or kettle?"
] | [
false
] | For a small-ish amount of water - say between one and three cups. The amounts you would use to make a cup of tea or some ramen. Efficiency in terms of lower cost (electricity and gas for a gas stove). | [
"http://www.treehugger.com/clean-technology/ask-pablo-electric-kettle-stove-or-microwave-oven.html",
"http://www.scientificamerican.com/article.cfm?id=stove-versus-microwave-energy-use",
"Depends on who you ask? ;) The answer is highly dependent on the EXACT combination of water volume, container used, microw... | [
"No, not all systems have identical efficiency.",
"Stoves tend to heat the air as well as the water.",
"Microwaves don't convert electricity to microwaves efficiently.",
"The question isn't how much energy goes into the water. That's the same for all systems. The question is how much energy gets used that D... | [
"This, from the scientific american article, is your answer. ",
"... the difference in energy saved by using one method over \nanother is negligible: Choosing the most efficient process might save \na heavy tea drinker a dollar or so a year. “You’d save more energy \nover the year by replacing one light b... |
[
"When does my body begin burning fat for energy?"
] | [
false
] | null | [
"Your body is burning fat all the time. It's also storing fat all the time.",
"There is also energy stored as glycogen in your muscles and your liver, and energy is constantly floating in and out of this system and your adipose tissue, so there isn't any 'time' when you switch from one to the other - just a gradu... | [
"That makes sense. Thank you. "
] | [
"This is a question for your physician, since they will know you better than any of us."
] |
[
"What makes some viruses seasonal?"
] | [
false
] | How do we know when something is "seasonal"? Are there any truly seasonal viruses? Is it really human behavior during the seasons that's key, or are some viruses just naturally only able to spread under certain seasonal weather conditions? Thanks for any help in understanding this. | [
"Probably the most research about seasonal viruses is based on flu viruses but this same trend holds true for many other respiratory viruses.",
"Although Flu is regarded as seasonal, flu cases happen year-round, they just seem to nearly always peak in December to February. ",
"https://www.cdc.gov/flu/about/seas... | [
"The winter of each. That is how, in the US, the CDC determines which flu vaccine to administer, by examining the strains of flu present in the flu season in the Southern Hemisphere."
] | [
"Most of the work has been done on influenza, even though several other viruses are almost equally strongly seasonal. It’s generally assumed that the reasons for seasonality are the same, but it’s not certain. ",
"For influenza, there are lots of explanations, but it's still not completely clear which of them is... |
[
"Can atoms give up electrons that are not in the outer layer?"
] | [
false
] | [deleted] | [
"With enough energy, yes. ",
"For example, X-ray photoelectron spectroscopy (XPS) uses x-rays to eject core electrons and then measures the kinetic energy of the ejected electrons to give an indirect measure of their energy level (binding energy) within the atom.",
"(Since the x-ray energy is known, and the tot... | [
"You can fully ionize anything using heat or high-speed collision with metal foil. You can also use a pulse laser to push the electrons away - the nucleus has a very different charge to mass ratio compared to its electrons so an electric field (ie laser) will move the electrons much more than it moves the comparati... | [
"Yes. For starters you can always apply more energy and get more electrons out. Actually this does happen naturally in superheated plasmas. In the case of sodium the second ionization energy is almost 10x higher than the first, so this is extremely endergonic and the resulting Na(2+) is a potent oxidizing agent.... |
[
"Can water be magnetized?"
] | [
false
] | I thought if you dissolved magnetite "dust" into water, you could magnetize the water. But then I realized if you put a magnet to it, it would just attract the magnetite. Is there any other way this can be done? | [
"Water is ",
"diamagnetic",
", and will generate a magnetic field opposed to an externally applied field."
] | [
"http://www.youtube.com/watch?v=A1vyB-O5i6E",
"If I understand correctly, the frog is levitated in that video due to the water within the animal being magnetized."
] | [
"Does anyone mind if I jump in on this question?",
"I was told that to magnetise something, you let it transition from it's liquid state to it's solid state in a strong magnetic field, and voila, all your electrons are pointing the right way and you have a magnet. ",
"So I immediately wondered wether you could ... |
[
"If coral reefs existed in the past when the earth was hotter why is the hypothesis that today the corals reefs are currently dying because the earth is too hot?"
] | [
false
] | null | [
" did the coral reefs exist in the past? And did they have the same organisms as today?",
"Stable temperatures give places where they can form and survive. Changing temperatures changes these places - and currently this change is faster than the formation of coral reefs."
] | [
"it's a matter of CO2 affecting pH in water, temperature increase is due to atmospheric effects also due to CO2. CO2 is what relates the distinct phenomenon of oceans acidifying and temperatures warming, the latter of which is much less threatening to coral at this point."
] | [
"Thanks for the explanation. When I looked at this page ",
"https://en.wikipedia.org/wiki/Geologic_temperature_record",
" for temperatures I did not account for the scale not being linear so it made the rate of change look much higher that it was."
] |
[
"[Biology] Carrots contain Falcarinol, which can potentially irreversibly block one of the Cannabinoid receptors. So, by eating carrots, is an individual permanently reducing their ability to feel the effects of cannabis?"
] | [
false
] | Falcarinol is found in carrots, celery, and a few other vegetables. And Falcarinol is a covalent inverse agonist to CB1 receptors. From my understanding, this means Falcarinol irreversibly blocks the CB1 receptors. And these receptors are densely packed in the brain on nerve cells, which don’t regenerate/reproduce. So,... | [
"Oh my gosh, no wonder I can't get high! ",
"Seriously, the cells may not regenerate, but those receptors are constantly turning over. Constantly.",
"Any effects would be temporary, as those receptors turn over you'd see less and less. "
] | [
"Plus the amount of falcarinol in these plants are too low to cause problems. We'd be suffering from far worse issues if the dose was high enough to block most of the CB1 receptors."
] | [
"The receptors are internalized and degraded and remade. Receptors are proteins, so we have genes that encode them and those genes will be transcribed regularly.",
"The term irreversible can be misleading sometimes. Some irreversible antagonists can be removed by binding the antagonist off with something else (se... |
[
"What happens if a person take caffeine and nicotine together? Net vasoconstricter or Net vasodilator?"
] | [
false
] | null | [
"As far as I know ( and I could be wrong )The combination is a great vasodilator. In some studies , nicotine actually doubled the rate in which the body gets rid of the caffeine. \nThe combination can trigger anxiety in some individuals."
] | [
"Caffeine is generally vasodilatory through the production of nitric oxide: ",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3003984/"
] | [
"This",
" says it produces cerebral vasoconstriction. This is why it can help treat headaches."
] |
[
"If I'm in a spaceship travelling at near light speeds, does the distance between me and my end goal shrink or expand?"
] | [
false
] | I understand when an outside observer views my spaceship it shrinks in the direction of motion. However, how do things look outside from inside the spaceship? | [
"Lengths can only contract, they can never be made ",
" than the proper length, in special relativity."
] | [
"This is matter physically getting ripped apart. It is not a distance getting longer from changing your reference frame."
] | [
"That's correct. That's why I specified ",
" relativity only. In general relativity, lengths can be shortened or lengthened."
] |
[
"Relativity and speed"
] | [
false
] | Hi, this might be a dumb question, it's about relativity. Let's ignore all the news about that neutrino (I didn't read up on it), then according to relativity theory nothing can move faster than light. My question is, relative to what? See, if nothing can move faster than light relative to e.g. the microwave background... | [
"The resolution to your puzzle lies in the way that ",
"velocities add in relativity",
". Here's the long and short of it:",
"Let's say you are moving west at a speed c/2 relative to me, and Albert is moving west at a speed of c/2 relative to you. In the land of Galilean/Newtonian theory, we expect that I wou... | [
"Nothing can move faster than ",
" relative to ",
". In some situations you can have particles traveling faster than the speed of light in a specific medium, see ",
"Cherenkov Radiationn",
", but the speed of light in a vaccum (c) is the speed limit of the universe.",
"What this means is that it is impos... | [
"Relative to any chosen frame of reference; the speed of light is constant and is the same for any reference frame.",
"The LHC works because the protons are never moving faster than the speed of light; velocity addition does not work the same way for relativistic speeds as it does for small, everyday speeds. For ... |
[
"Why do we get the feeling of \"pins and needles\" when blood-flow is cut to a certain part of the body."
] | [
false
] | simple question | [
"It is not the blood that is cut off, you are cutting off the nerve. Some cells don't send signals back, so your body does not know what is going on. When you remove the pressure the nerves start to communicate again, but it doesn't happen in an instant. When they are coming back 'on line' is when you get the pi... | [
"While this explains when it happens, it doesn't really explain why. Any more info on that?"
] | [
"Well, you cut off the ",
"nerve signals",
" from the brain. Once you remove the pressure they are able to start up again. ",
"The technical term is ",
"paresthesia"
] |
[
"Why is Supercritical Water Non-Polar?"
] | [
false
] | Edit and Answer Based off the Comments: The individual molecules of water in SCW are still polar. However, in bulk, SCW behaves as if it is non-polar. This is likely (not 100% certain) because with the increased kinetic energy of the molecules, the effect of hydrogen bonding is weakened. Furthermore, the molecules may ... | [
"The answer is simple. It's not non-polar.",
"I'm guessing you or somebody who told you got the idea from the fact that you can use the supercritical state of water to dry things without the capillary pressure destroying their fine structure. The water doesn't become non-polar, but it does stop sticking to itself... | [
"Sorry but you have been misinformed. Just because it acts as a non-polar solvent does not make the molecule itself non-polar. Nothing about the bonding of the molecule changes just because of a change in temperature or pressure. As other have stated, it is only because the polarity of the molecule becomes insignif... | [
"A professor mentioned that supercritical water is non polar and as such is used to dissolve organic compounds and matter. And it says pretty much everywhere online that it behaves as if it is non polar. I'm simply curious as to why. Thank you though!",
"Edit: Poor phrasing on my part. The individual molecules of... |
[
"Are compressed gasses more buoyant than when they are not compressed?"
] | [
false
] | • | [
"No. The buoyancy of an object is proportional to its density, so the more compressed a gas is, the more dense it is, and the less buoyant it is."
] | [
"This is why divers can still go underwater without tying a car to their weight belt"
] | [
"Hi roh8880 thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the followi... |
[
"How can the North Star appear fixed from any other view point on Earth other than the North Pole?"
] | [
false
] | I understand how the sky would appear to rotate around a center point when it's viewed from one of the axis of earth, but If I'm looking at the sky from anywhere else I wouldn't expect to find any fixed points. How can it be that long exposure images of the night sky always seem to have this fixed center? | [
"When you are on a merry-go-round and you look at the central pole, it's always in the same position relative to you. The same principle applies here. ",
"Polaris is on the imaginary line around which the Earth spins. And the earth is just a very large merry-go-round, so it behaves exactly as expected."
] | [
"As long as you're north of the equator, the north star (Polaris) will be above the horizon. Polaris is very close to the celestial pole (an imaginary point in the sky where the Earth's axis of rotation, indefinitely extended, intersects the celestial sphere).",
"At the north pole, Polaris appears to be directly ... | [
"This is wrong! Other than precession, if that's what you mean, it would not \"rotate\" out of position no matter where you were. Imagine a beam extending out of the Earth's axis to the north star. If you are looking up, right at the pole, you see the beam rise above you and touch the star, ",
"If you are standin... |
[
"Why are face transplants so rough?"
] | [
false
] | This might seem like kind of a brash question, I don't mean it to be. It seems like with all the advances in plastic surgery, facial transplants should be more convincing than they currently are. What are the reasons it's so difficult to make a convincing facial transplant? | [
"There are so many nerve endings. Not like with most plastic surgery, where it's one area of the face that is fixed. This is an ",
". ",
"I would assume there's a lot of tissue damage/tissue death involved as well. It's just a really difficult task."
] | [
"Also the face has grown to cover a specific bone structure. Putting it on a different bone structure is like wearing someone else's perfectly-tailored suit - it still looks like a suit and it's better than being naked but it doesn't look quite right."
] | [
"Hi, I'm new to ",
"/r/askscience",
".\nCan we continue asking relevant questions? \nFor instance, what if someone responds to the OP saying \"What could make the job easier? Do you know of any current methods used to partially deal with the issues?\" Or \"are partial skin grafts...\"\nAnd so on... \nI figure s... |
[
"Would I be able to breathe better in a forest than I would in a desert?"
] | [
false
] | I feel kind of ridiculous for even asking this but I feel like more trees around = more oxygen. Whether its easier to breathe or not, is there at least a small but significant difference in the oxygen levels? | [
"[citation needed]"
] | [
"askscience is not for educated guesses, it's about facts."
] | [
"I'm having trouble finding a citation, but I think there must be a small difference. The rainforests are responsible for ~40% of the new oxygen in the atmosphere each year (balancing the use in respiration), so these can serve as a \"source\" and thus have slightly higher oxygen concentrations. \"Sinks\" would i... |
[
"Is a rain (snow?) of carbon dioxide possible in Antarctica?"
] | [
false
] | Wikipedia says that temperature in Antarctica can be less than -80 °C. Carbon dioxide boils at -57 °C and melts at -78 °C, but I've never heard anything about such rain (snow). Is it possible or it isn't because of some reasons? | [
"It's cold enough, but there is very little CO2 in the atmosphere. You can't look at the sublimination point at 1 atm because the partial pressure of CO2 is much lower. The low partial pressure of carbon dioxide would cause it to subliminate in this environment--some molecules are freezing out, but at the same ti... | [
"atomfullerene covered your main question, but I'll add that phase transitions are pressure dependent, and carbon dioxide can't exist as a liquid at atmospheric pressure.",
"Phase diagram",
"Note that the liquid area is entirely above 5.11 atmospheres. At 1 atmosphere, it transitions directly from solid to gas.... | [
"The primary method to find past co2 data for the atmosphere is analyzing air pockets in ice cores.",
"Right, air pockets. CO2 is not precipitating out (as either \"rain\" or \"snow\") of the atmosphere in this case. As Davecasa and atomfullerene explained, it is impossible for many reasons primarily the fact tha... |
[
"In what form (or forms) are the thoughts of people who have congenital deafness? Are they purely visual? How is thought constructed?"
] | [
false
] | As a hearing person, I have an inner monologue in my own voice and in the imagined voices of others, but I wonder: what is going on in the heads of those who have never heard language? I am fascinated by the notion of this sensory experience of the world, visual, felt on the skin and in the bones (in gesture and propr... | [
"Im not deaf, but unless im frustrated about something my 'inner monologue' isnt in language. Its just concept links and i would assume thats how a deaf person would think in general.",
"Concepts are efficient after all. You can think of \"a guy drinking water at the side of a river\" in one instant. Its ... | [
"The memory models defining in that fashion arent wrong. They are correct to the point where letters are a prerequisite for words (in english at least, not true for kanji).",
"Communicating your thoughts requires language. And to an overwhelming extent the majority of the concepts we understand were originally ... | [
"The Sapir-Whorf hypothesis is almost certainly wrong in it's strongest forms, and it's unclear the extent to which language is a requirement for thought or whether it simply influences thought. ",
"I also think any study of language is usually confounded by human interaction. In other words, \"natural experime... |
[
"Why can't we point a telescope at the center of another Galaxy and see the warped space that would theoretically surround the black hole at its center?"
] | [
false
] | null | [
"The Hubble telescope can see things about .05 arc seconds small. The Andromeda Galaxy is 2,538,000 light years away which means Hubble can see something .624 light years across or 5.9x10",
" Km. The super-massive black hole in our galaxy is a maximum of 6.25 light hours across and applying the Schwarzschild radi... | [
"While ",
"/u/washyleopard",
" is right that the black hole is far too small to be resolved with our telescopes we can see some effects.",
"Gravity is the warping of spacetime, and we can observe stars moving incredibly quickly very near the black hole.",
"This animation shows the motion of stars near Sag A... | [
"I am not sure, but very likely. from the trajectory it appears to be in front of the plane of the picture."
] |
[
"If a first-world person had to store their own waste (garbage/rubbish, not human waste) instead of sending it to landfill, how much space would it require over a lifetime?"
] | [
false
] | Assuming nothing gets recycled, the person is literally just collecting every piece of garbage that would otherwise go to landfill. Would we be talking about a swimming pool sized volume? Or more? The reason I ask is that I'm a little surprised there aren't more landfill sites all over the place considering how many pe... | [
"A cubic meter of water weights a metric ton. There is no way your trash is approaching the density of water even if bricked by a compressor, so it would be a lot bigger than that storage vessel. I don't know the average density of garbage so I can't give you a better estimate though."
] | [
"I think a lot of these answers are missing the point. I just took an Environmental Engineering course on landfills, and here's the data they gave us:",
"A person generates around 5kg of waste per day, which includes a tolerance for industrial waste generated by the products that you use (this would be around hal... | [
"People generate around 2.5 pounds of trash a day, not including around 54% that is recycled. So let's make it an even 5 pounds a day.",
"Multiply that by 365 days a year and around 80 years and you get 146,000 pounds, or 66 tons. That's equivalent to around 66 meters cubed.",
"That can't be right though - seem... |
[
"Is hemp really a miraculous plant that could replace dozens of products at a cheaper cost?"
] | [
false
] | null | [
"Hemp isn't a 'miraculous' product, per se, but it is useful and could be a cheaper or more effective replacement for a few different materials if grown industrially. The reason people seem to sing its praises and make it sound like a miracle product is because right now in North America you pretty much can't grow... | [
"This is a friendly reminder from the moderators of AskScience to please refrain from posting a top-level comment to this post unless you have a scientific, evidence based point to contribute. Anecdote and speculation are not welcome, but followup questions certainly are!"
] | [
"Just to be a nitpicker, in 1998 Canada changed its laws and now allows hemp to be grown for industrial purposes, so we can't grow it in the United States not technically all of North America. "
] |
[
"where does epinephrine comes from? The one used for people with allergies because Google only says It comes from glands so I don't understand if it's donated or sintethized by other means."
] | [
false
] | null | [
"Extraction and purification of adrenaline from the adrenal glands of cattle and sheep is one way you can produce it at scale. Since the early 1900’s though synthetic production of epinephrine has been ongoing, and generally involves reacting catechol and chloroacetyl chloride.",
"https://www.thelancet.com/journa... | [
"Well the animals are killed, the adrenal glands sit on top if the kidneys, but you have to keep in mind that cattle and sheep aren’t exactly ",
" used for that. So yes, this harms the animal in that they’re killed, but the environmental impact is the same as raising any livestock, and the animals required to sup... | [
"Epinephrine is a small molecule. It doesn‘t matter where you get it from. If it is pure it is identical.",
"Doesn‘t matter what animal, planet or universe you get it from.",
"Insulin for example is different, because that‘s just a class of peptide hormones, not a specific one. Meaning human insulin is slightly... |
[
"Hey guys. I posted this in r/crazyideas but was wondering if it was feasible at all. It involves a remote pair of robotic hands to perform tasks such as mechanic work and surgery."
] | [
false
] | null | [
"i hate to be the bearer of bad new",
"Replace gel with finger clamps with resistance and you're about 5 years behind the next big thing in surgery. "
] | [
"The first remote surgery was performed back in 2001. The robotic \"hands\" however can be made vastly superior in accuracy and range of motion - designed exactly for the task required - than mere human hands can so there's no goo making a model of them."
] | [
"Check out the ",
"wiki article",
" especially the section on delay in data transfer required to attempt to duplicate instantaneous sensory feedback as well as the section entitled 'limitations'."
] |
[
"Why do we think matter warps space and not that warps in space attract matter?"
] | [
false
] | null | [
"It's clear that the presence of mass is always associated with a warping of spacetime. It follows naturally to assume that some invisible matter is causing the extra warping to occur in galaxies. While what you're proposing isn't impossible, it simply isn't the most simple possible explanation for what's occurin... | [
"Mass and energy to be more exact. It's certainly ",
" that something else can do it, but I don't think we have any indication that that's the case. "
] | [
"Because we ran some tests. ",
"Imagine the following experiment: Two spheres attracting each other, negligible friction. Note that iron has way lower density than gold."
] |
[
"Why is it that warming a cold, dead, electronic device will sometimes give it a substantial charge?"
] | [
false
] | I have noticed this in the past but it really struck me today when I got into my car and tried to plug my ipod (which had been sitting in freezing weather for several hours) into the speakers. It was totally drained of battery. So, I turned the heat on full blast and set the ipod in the vent for a few minutes and whe... | [
"It's also because the battery gives power through the chemical reactions in the battery, which run faster when temperatures are higher. "
] | [
"It's also because the battery gives power through the chemical reactions in the battery, which run faster when temperatures are higher. "
] | [
"Yup. It's called electrolytic conduction ;D",
"http://www.google.com/search?hl=en&tbo=d&site=&source=hp&q=what+is+electrolytic+conduction&oq=what+is+electrolytic+condu&gs_l=mobile-gws-hp.1.0.0l2j0i30j0i8i10i30.1988.21937.0.23391.27.19.0.8.8.0.824.4184.10j4j1j5-3j1.19.0.les%3B..0.0...1ac.1.E5l773T3qTo",
" "
] |
[
"How much of our body is made up of other organisms?"
] | [
false
] | or other animals' bodies for that matter. | [
"I can't comment on the mass of you vs. non-you in/on your body, but I recall in college microbiology learning that the organisms in and on your body outnumber your own cells by an order of magnitude. ",
"Bacteria are normal inhabitants of humans (as well as the bodies of upper animals and insects) including the ... | [
"There's some answers here regarding bacteria: ",
"http://answers.google.com/answers/threadview/id/208733.html",
"TLDR answer: typical human has 2-9 pounds of bacteria (which are much smaller than human cells). "
] | [
"From Wikipedia:",
"\nThere are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number[12][13] (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither... |
[
"Hard Drives in Space"
] | [
false
] | If a spinning HDD were to be put in a small probe or satellite, would its spin have a gyroscopic effect on the probe? If we've ever done this, are compensations needed when designing it? Also, would the disk need to always be spinning because wouldn't stopping it cause a huge change in momentum? | [
"If a spinning HDD were to be put in a small probe or satellite, would its spin have a gyroscopic effect on the probe?",
"Yes, it would. In particular, increasing or decreasing the spin rate of the HDD would put some spin on the craft. Generally this would be negligible, but over long time periods you would certa... | [
"If a spinning HDD were to be put in a small probe or satellite, would its spin have a gyroscopic effect on the probe? ",
"Yes, of course.",
"If we've ever done this, are compensations needed when designing it?",
"\nAlso, would the disk need to always be spinning because wouldn't stopping it cause a huge ch... | [
"I figured solid state drives were preferred because of no moving parts (partly for the momentum and also for reliability and failure rate). What about the computers in the ISS? Were large enough SSD's in existence when it began? Or is the mass becoming large enough that the change in momentum is negligible?"
] |
[
"Can someone explain why the integral of 1/x^2 from 1 to infinity = 1, but 1/x = infinity?"
] | [
false
] | [deleted] | [
"Note that the region underneath 1/x has an interesting geometric property: If you take the part between x = 1 and x = 10, say, and you flatten it by a factor of 10, and then stretch it horizontally by a factor of 10, then because 1/10 * 1/(x/10) = 1/x, what you get is the same shape as the part between x = 10 and ... | [
"You can start to see it yourself, just by playing around. ",
"Start adding up a couple terms of the series 1/x",
" vs 1/x, just letting x be the integers. ",
"If you look at 1/x",
" you'll get something like:",
"1 + 1/4 + 1/9 + 1/16 ~= 1.4236",
"And you can play with your calculator and see no matter h... | [
"I don't think the difference between convergence and logarithmic divergence is something one can \"see for oneself\" very easily. If you naively set up a computer to add terms one at a time, it's sure going to look like the series is converging. For any computer, there will be a (fairly small) number such that the... |
[
"Does Porn Consumption Have Negative Consequences?"
] | [
false
] | [deleted] | [
"There was an Italian study done that showed a link between internet porn use from an early age and sexual dysfunction. There's a ",
"Psychology Today Article",
" about it. Basically it can cause desensitization of your brain to ",
" sexual stimuli. Especially if the porn consumption began before sexual inter... | [
"Not as far as anyone can tell. The only major study I know done on it was the 1970 ",
"President's Commission on Obscenity and Pornography",
" which was setup by Congress to give political cover to banning or regulating it. After more than a year of study, they concluded that there was no discernable harm done... | [
"There are some preliminary studies that actually show porn may be beneficial and be a cause of lower sex crimes:",
"http://skeptics.stackexchange.com/questions/6656/is-the-increasing-availability-of-high-speed-internet-pornography-reducing-sex-c"
] |
[
"Why is the heat capacity of salt water lower than freshwater?"
] | [
false
] | [deleted] | [
"Okay, so ice has a lower heat capacity than liquid water. Does that mean ice has fewer hydrogen bonds as well? (It doesn't) Extending the same that rationale to another substance: Covalent bonds store vibrational energy as well, graphite forms fewer bonds per mole than diamond does, thus graphite has a lower heat ... | [
"The hydrogen bonds that form between water molecules can store heat as potential energy of vibration. Salt water forms fewer intermolecular hydrogen bonds (per molar quantity) than regular water because the sodium chloride ions are now interacting with the water molecules. Thus the reduction in heat capacity.",
... | [
"Cool, that makes sense. Follow-up question: salt water has been proven to evaporate more slowly than freshwater. Wouldn't a reduction in heat capacity facilitate more aggressive evaporation?"
] |
[
"How exactly does nutella \"release energy slowly\"?"
] | [
false
] | [deleted] | [
"http://www.wolframalpha.com/input/?i=100g+peanut+butter",
"http://www.wolframalpha.com/input/?i=100g+nutella",
"Based on that nutritional information, I suggest that peanut butter is healthier than nutella. Far less sugar (8g v 54g per 100g), more vitamins, more protein, etc. However, IANADietician."
] | [
"It's perfectly plausible that Nutella is fairly low-GI. It has a lot of vegetable oil. Fats and oils are large molecules that take a long time to break down and digest, and also slow down the absorption of everything else: eating sugar+fat will give you a ",
"lower glycemic response",
" than the sugar alone.",... | [
"Otherwise, Nutella isn't breakfast. Nutella is frosting.",
"Liquid candy bar.",
"http://www.wolframalpha.com/input/?i=100g+nutella",
"http://www.wolframalpha.com/input/?i=100g+snickers+bar"
] |
[
"Why are there massive tornadoes in US, but almost none in South America and Asia or Africa?"
] | [
false
] | null | [
"There have been documented tornadoes on every continent EXCEPT Antarctica (figures). But you are correct in that the majority of the earth's tornadoes happen in Tornado Alley in the United States. This is because of a very unique weather system that only the USA sees. ",
" air moves south from Canada and mixes w... | [
"As a master's student in meteorology, I approve this message."
] | [
"Here I am. Meteorology Ph.D student, and I approve of all of the above messages."
] |
[
"Could there be anything more fundamental than quarks, bosons and leptons?"
] | [
false
] | If we zoomed in on matter even further than the three categories of subatomic particle discovered so far, is it possible that we could see something more fundamental, perhaps something that is a constituent of all three types? Or have these particles been proven to be the most fundamental? | [
"Quarks and leptons being composite, as in being bound states of some constituents, is a very disfavoured hypothesis, for a reason I explained ",
"here",
".",
"Gauge boson compositeness does not make a lot of sense, I think. Higgs compositeness instead is still an open question as far as I know.",
"Now it's... | [
"There could be, but there's no evidence of it, and no real necessity to have that be the case. "
] | [
"is a very disfavoured hypothesis, for a reason I explained here.",
"I don't think a \"one off\" tuning is a particularly strong argument. If the tuning is radiatively unstable then there is an argument (hence higgs and CC problems)."
] |
[
"What does it mean that a photon has an oscillating magnetic field perpendicular to an oscillating electric field?"
] | [
false
] | I’m speaking particularly about the common representation of a photon as two in-phase sine waves at right angles to each other. exactly is oscillating? A couple places said it was the magnitude of each respective field, which I think refers to the strength and length(?) of the field lines “generated” by the field. But ... | [
"I’m speaking particularly about the common representation of a photon as two in-phase sine waves at right angles to each other.",
"That's a classical electromagnetic wave which is not the same as a photon which is the quantum of the electromagnetic field. ",
"( ",
"https://physics.stackexchange.com/questions... | [
"Sorry I don’t really understand EM waves at all and I’m probably dumb for trying to understand with a cursory knowledge of physics.",
"Don't worry, the EM field is ",
" hard to visualise and it's very common to get confused when thinking about it. I think one of the main problems is that people imagine somethi... | [
"Thanks for this reply. Would you mind elaborating on what it means for an amplitude to be discrete?"
] |
[
"Why is the energy and mass in quasar accretion disks not simply pulled into the enveloped black hole?"
] | [
false
] | I can't understand what forces are at play in quasars. I understand there is a matter pile up and subsequent expelling of that matter due to gravitation and friction but I don't understand the . Why is this all piling up near the event horizon instead of being seamlessly sucked in? | [
"Because angular momentum is conserved. Earth doesn't simply fall into the sun because of the very same reason, so those gas particles orbit the black hole in exactly the same fashion, just in a much lower orbit. Only through friction they can slowly lose angular momentum, so they do approach the black hole after a... | [
"That's not really my specialty, but as far as I know, that's not entirely clear. The stuff heats up and becomes a plasma, which induces strong magnetic fields. Hydrodynamics are notorious for their complex equations, but with magnetic fields and relativistic fluids in the mix it becomes a real challenge. It's call... | [
"Oh, cool! Clear as day. Cheers for that"
] |
[
"Does science have theories which are non-falsifiable?"
] | [
false
] | I would like to refute this statement, which I stumbled across on a forum, if it is untrue: "Science pushes this notion but actually has theories than are not falsifiable, namely The beginnings of the universe(Big bang, ect, ect) and Life from non life(abiogenesis)" So basically I would like to defend science (and lear... | [
"All scientific theories must be falsifiable, in principle, using new evidence. ",
".",
"Can't be simpler than that.",
"A corollary is that scientific theories cannot ever be proven true, only false. Philosopher John Stuart Mill summarized this outlook best when he said, “No amount of observations of white sw... | [
"I don't believe that there is a standard accepted theory of abiogenesis. It is an open question.",
"Here is an analogy for the big bang problem:",
"If you come upon the remains of a forest with charred wood and ashes everywhere, you will conclude that there was a forest fire. You can do this because you have l... | [
"The Big Bang is a falsifiable theory-- if it were demonstrated that the Universe was either static or in a ",
"steady state",
", the Big Bang would have been disproved."
] |
[
"Why is three phosphorylations the limit of Adenosine and not two or four?"
] | [
false
] | Totally not procrastinating listening to protein kinase lecture. | [
"Well, adenosine di- and tetra- phosphate both exist in biological systems, so tri- is definitely not the limit. Why tetra- isn't used as the 'energy currency' of the cell is beyond me, though I'd hazard a guess that the bond involved in getting that fourth phosphate on there doesn't have as good a payoff as the th... | [
"In order for A4P (aka AP4) or A5P (aka AP5) — both of which do exist in biological systems — to be used for energy storage, you'd need a few things to happen.",
"First, they'd need to be sufficiently more efficient to justify the metabolic cost of additional enzymes (A4P synthase and A5P synthase). If they aren'... | [
"The amount of energy needed to add the next phosphate exponentially increases, due to the strong repulsion of the negative charge. I would hypothesize, the amount of power provided by the atp synthase is insufficient to add a 4th phosphate. If an adenosine-4-phosphate does exist, it is likely from a substrate l... |
[
"Gravity assist: I'm imagining a planet shaped like a torus, and an object passing through the hole. Does the object acquire orbital velocity if it enters in the direction of the planet's orbit (\"catches up with\" it), and lose velocity if it goes the other way (the planet \"catches up with\" it)?"
] | [
false
] | In case I was unclear, I'm trying to understand whether this "donut" model is the same thing as a traditional gravity assist ( ). | [
"Relative to the planet, yes. However, the important thing here is the change of the velocity vector. This is exactly how planetary assists in orbital mechanics work. While you exit the planet's sphere of influence with exactly the same speed as you entered, you're pointing in a completely different direction. ... | [
"So, in layman's terms, and feel free to correct me if I'm wrong, while the craft would speed up due to gravitational attraction in the way in, it would slow down by the same amount on the way out, regardless of direction of travel. Thus making your net speed change zero."
] | [
"For a gravity assist, you need to enter and leave the planet's influence in different directions, AFAIK."
] |
[
"In the LHC how are protons removed from the nucleus of an atom and kept together?"
] | [
false
] | I read somewhere there are billions of protons flowing round the LHC, how are they isolated and kept that way? What happens to the neutrons and the other parts of the atom? Thanks! | [
"The proton bundles in the LHC start out as hydrogen. To be more specific, they start out as hydrogen from the bottle shown in ",
"this picture",
".",
"Since a hydrogen atom is just 1 proton and 1 electron, we don't have any pesky neutrons to worry about. So that's easy.",
"What's also useful is that proton... | [
"You can also find the picture in this blog post:\n",
"http://backreaction.blogspot.ch/2010/02/lhc-proton-source.html",
"It's a really unimpressive bottle considering the amazing stuff that they do with its contents."
] | [
"Do you have another link to the image of the \"hydrogen bottle\"? I just get \"Problem loading page\". I'd really like to see what it looks like. "
] |
[
"How does the light emission of a solar cell benefit the efficiency?"
] | [
false
] | null | [
"What do you mean by \"light emission of a solar cell\"? Solar cells don't emit light."
] | [
"They do, but I fail to see how it makes sense that it actually increases the efficiency. I edited the post, hoping its more clear now."
] | [
"https://arstechnica.com/science/2012/04/solar-cells-must-emit-light-to-attain-perfection-research-suggests/",
" This is an article suggesting so for example"
] |
[
"How many ants would it take to hold up a horizontal human?"
] | [
false
] | null | [
"Assuming...",
"mass of ant: 3mg",
"strength of ant: 50 times its body weight --> 150mg",
"length of ant: 10mm",
"width of ant's body: 2mm",
"area of ant: 10x2 --> 20mm",
"density of human: 1.4mg/mm",
"depth of lying human: 100mm",
"mass per unit area: 140mg/mm",
"According to my rough calculation... | [
"Wow! Thank you for your reply! Would it be impossible to calculate roughly how many ants it'd take to lift a small child (or at least attempt)?"
] | [
"if ants can stand on one another they can lift almost anything. ",
"How? What do you mean?"
] |
[
"How do electron microscopes produce 3D looking images with depth and shadows?"
] | [
false
] | If only electrons are being used, how are images like produced. . | [
"The 3D images produced by electronic microscopy most likely come from a specialized form called Scanning Electron Microscopy. In SEM, a primary electron beam is used to scan the surfaces of objects, but rather than the beam passing straight through (such as with Transmission Electron Microscopy), particles are emi... | [
"The image you have posted is from a TEM which I know because it is of such a very small scale (100nm for the scale bar means this is very very tiny, those salt crystals we're probably on the order of 10-100um and were 1000X bigger). In order to take a TEM image you have to slice a piece that is nanometers (nm) thi... | [
"Adding to this answer, the 3 dimensionality is inceased because some of the electrons don't bounce back elastically. Some of the electrons penetrate the sample and lose some energy the the atoms in the specimen. They bounce around and can penetrate up to a few microns. If they end up bouncing around and end up lea... |
[
"If you're standing on Jupiter's moon and jump, do you jump noticeably higher on the side closest to Jupiter than on the side furthest from it?"
] | [
false
] | null | [
"The astronaut jumping on Io should be visualized as being similar to the ocean on Earth affected by tides. Your weight is lowest on Io where Jupiter is directly overhead AND on the opposite side of Io, where Jupiter is directly under foot. Your weight will be highest on Io on the circle 90 degrees from those two... | [
"The Jovian gravity cancels out with the centrifugal force.",
"This is true for the center of mass of the moon, but not true for every point (hence tidal forces). The surface gravity of Io is 1.8 m/s",
" The difference in gravitational acceleration from Jupiter between Io's surface and its center is ~0.006 m/s"... | [
"As the moon orbits Jupiter, and you are standing on that moon, you will be in an orbit around Jupiter as well. That means both you and the moon are in freefall around Jupiter, and weightless with respect to the planet. There are some tidal forces, but from your perspective, Jupiter doesn't really matter. The only ... |
[
"Why don't particles spontaneously decay?"
] | [
false
] | From what i understand of the atomic nucleus, there are two forces at play: the weak and the strong nuclear forces. Generally when you get to the heavier elements, the size of the nucleus becomes such that because the strong force works only in very short distances, the atoms become less stable and you get radioactive ... | [
"Are you familiar with the concept of quantum tunneling? Basically it's a phenomenon where a particle is in a potential, but has a finite probability of crossing that potential barrier and appearing on the other side, even though classically this would be forbidden. An example would be if you had an egg rolling aro... | [
"Remember that everything we're talking about right now is ",
" non-deterministic.",
"You can imagine, if you like, that God has a clock, and that things only happen when the clock ticks, and not in between ticks. Each time the clock ticks, there is a ",
" for an alpha particle to tunnel out of a suitable nuc... | [
"Basically the energy height of the potential and the kinetic energy of the particle."
] |
[
"Slightly complicated permutation?"
] | [
false
] | Hi, someones comment on a thread claiming that the number of possible combinations of a deck of cards would be doubled if the back of the cards could be used - which I'm pretty sure is wrong, so I guess that is essentially my question. How does one go about calculating a permutation such as this? I would imagine it to ... | [
"The problem isn't quite fully specified, so I'll answer the two questions that I think it could be.",
"How many ways can you order a deck with some number of cards are face down, considering the ordering of the facedown cards?",
"In this, a six of hearts face down is filling a position in the sequence, so they... | [
"This assumes that a face down Queen of Spades is distinguished from a face down Seven of Diamonds, which may or may not be appropriate.",
"If the backs of cards aren't distinguishable, this becomes a much harder problem, I think. ",
"If n cards are face down, then there's 52! ways to order the deck, 52Cn ways ... | [
"Awesome, glad I could help."
] |
[
"Is the energy produced by the sun constant?"
] | [
false
] | whether it be on a microsecond by microsecond or hour by hour basis, is the power produced by the sun constant? I know that the sun will eventually run out of fuel but I am really wondering if there are fluctuations. | [
"No. In the long-term trend it is gradually getting hotter, in the short-term the solar output fluctuates over an 11-year cycle corresponding to different numbers of active sunspots."
] | [
"in the short-term the solar output fluctuates over an 11-year cycle",
"To expand on this a bit: ",
"this fluctuation is very small",
". On average we receive 1366 W/m",
" of flux from the Sun, and that only really varies by about ± 1 W/m",
", which in percentage terms is only ± 0.1%.",
"Since I've seen... | [
"in the short-term the solar output fluctuates over an 11-year cycle corresponding to different numbers of active sunspots.",
"That is the energy released by the surface of the Sun, not the fusion power (\"produced\") in the core."
] |
[
"Assuming Mars harbors/harbored life, what are the chances that it could contain fossil fuels as we currently know them?"
] | [
false
] | ... And I suppose a more compelling question would be what other usable resources might Mars contain? | [
"Ah, but we DO detect methane in Mars's atmosphere. Interestingly enough the emissions peak during the martian summer and drop off during fall/winter. "
] | [
"I'd be surprised if there were oil deposits. I think we would have detected methane in the atmosphere if there had been such a large amount of biomass on mars in the past. At least if it were biomass like earth's."
] | [
"I think that's unlikely because for fossil fuels to form you need a large and thriving ecosystem with huge amounts of biomass that existed for millions of years, coupled with an appropriate active geological system, which seems unlikely to have existed on Mars.",
"In addition, I think that if such things existed... |
[
"Why did the Russian computer, Setun, a ternary computer, offer advantages such as lower electricity consumption and lower production cost over its binary successor?"
] | [
false
] | I am a computer science major and I have been taught that memory costs money. That being said wouldn't a ternary computer use more memory? Or have more parts? Was the technology of the time more suited for three valued logic over Boolean logic? | [
"Computers can be built using any arbitrary radix. Some early machines were base 10. I can't find much information on Setun, however, nobody would claim the USSR ever had any sort of edge in computing, despite the country's strong reputation for maths. It is possible the limited electronics available in the USSR we... | [
"I found the concept!",
"It's called radix economy and if you allow non-integers as a radix then ",
" is the best in terms of radix economy. ",
"Base 3 has some marginal advantage overall, in terms of the radix economy, but base 2 has other advantages which have been pointed out by you and other people.",
"... | [
"Possibly. If you have a ternary system you may have attributes such as the transition time which works better. For example, if you define 0 volts as 0, 2.5 volts as 1, and 5 volts as 2 in a ternary system, and 1 as 5 volts in a binary system. At the same switching speed (volts/microsecond) you'd be able to transit... |
[
"What is the relationship between momentum and kinetic energy"
] | [
false
] | they seem so much alike, but totally seperate in all of their uses. | [
"To expand a little:",
"Momentum is often designated by \"p\". We'll call kinetic energy KE.",
"From mutatron's first line follows:",
"KE = p",
" / 2m",
"So there's your direct relationship between classical momentum and kinetic energy."
] | [
"That is the definition that is generally used in grownup physics."
] | [
"Momentum is m*v, and kinetic energy is 1/2 m*v",
" .",
"You can get the force for stopping something in time ",
" using:",
"F = m*v/t",
"Or you can get ",
"force for stopping something in distance ",
" using",
":",
"F = (1/2 m*v",
" )/d"
] |
[
"Why are there no green stars?"
] | [
false
] | Most stars are either blue, white, red, or orange, but why are there no green ones? | [
"Because stars radiate roughly a blackbody spectrum. As the temperature increases, the blackbody color changes as red -> orange -> yellow -> practically white -> bluish white. Then it stays bluish white all the way to infinite temperature.",
"It's called the Plankian locus - Wikipedia has a nice diagram:",
"htt... | [
"Oh I see, similar to the colors in normal fire?",
"It's exactly the same thing, because the light from the flame of burning wood or a candle IS black-body radiation. ",
"A yellow flame is caused by glowing soot particles. When the hydrocrabons (like those in wood or wax candles) burn, the combustion reaction (... | [
"Stars emit radiation over a broad range of wavelengths, and the human eye is most sensitive to yellow and green radiation. When a star is green, it is pretty much right in the middle of the visible spectrum. It is radiating strongly at all visible wavelengths, with most of the radiation right in the middle. When w... |
[
"Evolutionarily, why would mosquitos change to the point that they are itchy nuisances to their hosts instead of being unnoticeable?"
] | [
false
] | My only guess is that humans are the ones who adapted, not mosquitos. Maybe we adapted to get itchy mosquito bites because mosquitos carry disease, and it's better if we avoid them. | [
"Mosquito saliva actually contains an anesthetic which prevents you from feeling the bite as it is happening. It only gets itchy later (human immune response) by which time the mosquito is gone."
] | [
"They are usually unnoticeable. You usually only notice a mosquito bite after the mosquito is long gone and you present no danger to it."
] | [
"The itch happens after the mosquito is safely away, so it doesn't matter to the bug."
] |
[
"How much does a covid-19 vaccine lower the chance of you not spreading the virus to someone else, if at all?"
] | [
false
] | null | [
"Before you can pass the virus on to someone else, you must first become infected.Vaccines reduce this massively, with efficacies between 60 and 90%. ",
"https://www.nature.com/articles/d41586-021-02261-8",
"Once a person is infected, the adaptive immune system means the infection is cleared from the body more... | [
"Thanks to this sub-thread, I've booked in for my vaccine tomorrow. ",
"I'm not anti-vax (childhood rubella left me deaf), but I had some questions about this one. Finding some of those answers without the name calling and condescension that seems to be the default for any discussion on the topic these days is he... | [
"When playing the lottery you can either win or not win -- 2 possible outcomes but that does not make the chance 50-50"
] |
[
"Does radioactive decay of an atom cause significant changes in the properties of chemical compounds?"
] | [
false
] | I am not asking about the radiation, what I mean is, for instance if F-18, used in Pet scans, decays to oxygen-18, the resulting oxygen will be unsaturated. Will it immediately react with another molecule in its surroundings? What about metals in organometallic complexes, will they instantly change configuration if the... | [
"Technically speaking you can refer to either Beta + or Beta - decays, which emit either a positron or an electron respectively. (Yes this was pedantic)"
] | [
"Perhaps pedantic, but critically important to the application that OP asked about, Positron Emission Tomography. If berry's decay were only electrons, then PET would not be possible. "
] | [
"Not sure if you're kidding or not, but the detectors for PET don't detect the positrons produced by beta",
" decay themselves, but rather the gamma rays produced by positron-electron annihilations."
] |
[
"Why does solar pressure cause rotations of the JWST instead of just pushing it away uniformly?"
] | [
false
] | I've been curious about this for a long time and I expected that when the Aft Momentum Flap was eventually deployed (as it was today), there would be more layman-accessible explanations of this; however, I've not found any. My naive first guess about how solar pressure would affect JWST would be that the force would be... | [
"If the force doesn't act through the center of mass it will induce a torque. If you push sideways on one end of a rod you won't move the whole rod in that direction, you would rotate the rod. The momentum flap provides a counteracting torque to keep the telescope from rotating."
] | [
"Oh, I see! That makes so much sense, thank you.",
"All we need to do now is build a telescope that is perfectly spherical with uniform density, then we can get rid of that pesky momentum flap. :D"
] | [
"Project Echo",
" perhaps?"
] |
[
"When our sun turns red giant, will it push all the planets away or suck them all in?"
] | [
false
] | the mass of the sun wouldn't change right? so I don't see how it would suck us in. Would it have a slow wake or pressure wave that pushes the orbits of the planets away from itself? all the simulations I've seen on TV just show static planets sitting there waiting for a sun to swallow them, can't see that happening. | [
"The Sun shouldn't create too much of an outward force as it expands (by a pressure wave or anything), and as you noted the mass stays the same and so, due to a nice feature of Newtonian gravity, the Sun's gravitational field won't change either. So it's pretty accurate to think the inner couple of planets will jus... | [
"That's the opposite of weird. What would be weird is if stellar evolution somehow magically caused the sun's gravitation to change in a sufficiently significant way to alter the orbits of the planets."
] | [
"That works better when you remove \"the opposite of\"."
] |
[
"Why are there no nuclei consisting exclusively of neutrons?"
] | [
false
] | null | [
"There are no bound nuclei, but there are resonances like the dineutron. There is also the more controversial tetraneutron.",
"But these systems are unbound, and decay with half-lives on the order of 10",
" seconds.",
"If you take a system of two neutrons at low relative momentum, there is an attractive inter... | [
"Those are held together by gravity, not the strong force."
] | [
"No, because the nuclear binding energy is dependent on the total isospin of the system. Helium-4 has isospin 0 in the ground state, but the tetraneutron must have total isospin 2.",
"Or if you think of nucleons occupying some mean-field orbitals, Pauli exclusion means that the extra two neutrons in the tetraneut... |
[
"When a child receives an organ transplant (heart, kidneys, etc.), does the transplanted organ grow along with them as they get older? How does it know what speed to grow at?"
] | [
false
] | null | [
"The transplanted organs will grow appropriately with the child as they age as they would have in the donor's body as is governed by the normal cell's cycle and physiologic changes. ",
"EDIT: thanks reddit, turns out that children generally above the age of 2 can receive a transplanted kidney from an adult (",
... | [
"It does grow along with them, your bodies growth and all the organs within it are regulated by hormones so they secrete the hormone telling it to grow based upon the need for that organ."
] | [
"Growth Hormone (GH) dictates gross growth, and is secreted by the pituitary gland. This is the place where a lot of endocrine functions are regulated, to make sure your entire body is listening to only one master system.",
"Also, a lot of organs can undergo cell proliferation (hypertrophy) or cell enlargement(hy... |
[
"How do scientists know we've only discovered 14% of all living species?"
] | [
false
] | EDIT: WOW, this got a lot more response than I thought. Thank you all so much! | [
"It's basically extrapolating from data. One way of finding new species is (nowadays, less invasive methods are preferred) to go to the Amazon (or any other biodiverse ecosystem) and find a large tree (which shouldn't prove much of a challenge), spread a large sheet beneath the tree and then gas the whole tree to s... | [
"There have been many different estimates given for the total number of species on planet Earth. Some estimates are mere educated guesses by experts, while others are more grounded in statistics. A famous estimate was provided by Terry Erwin, an entomologist working for the Smithsonian Institute. He sampled beetles... | [
"Same, I pictured a mad scientist nuking entire Atolls so he could count Ants after"
] |
[
"Solar highways were on the table in 2008. Why haven't they taken off? What are the downsides?"
] | [
false
] | explains a really awesome idea for solar paneled highways. Sounds great, and they do a good job selling it, but why haven't we heard anything about it? This video's pretty old. Seeing as they were commissioned by the Department of Transportation to come up with this stuff, why hasn't it taken off? What isn't working? | [
"The gentlemen who was doing the solar highway project from the Department of Engineering has moved onto the next level of development. They are looking to build a mile or so of actual product in the real world and test it. They are probably testing or building it right now as I read a long while ago that he had al... | [
"and lastly...sorry for all these replies - I am on their facebook page (",
"http://www.facebook.com/pages/Solar-Roadways/41869107125",
") right now and am going to post a couple of questions about the status of things. It looks like they stay close to Facebook and we might get an answer sooner than later."
] | [
"http://solarroadways.com/",
" - this is the companies website (which totally sucks)",
"http://solarroadways.com/intro.shtml",
" - this is the info page, I am just starting to read it."
] |
[
"How can all the immense complexity of human organism be coded in only few tens of thousands of genes?"
] | [
false
] | Development, immune system, repair mechanisms, brain, eye, language, consciousness, all the tissues and chemicals ... how is it possible that so much information only uses so little code? Where's the compression coming from, if it exists? | [
"It's actually not that 'little' of code, if you want to look at it that way. The human genome consists of over 3 billion base pairs - and while we can consider only about 15% of those base pairs to directly code for proteins, the other 85% are slowly being determined to control other things (like protein interacti... | [
"To expand on the part about base pairs that do not code for protein, I would add that a big part of complexity comes from when and where genes are expressed in time and space. This can be controlled by regions that control transcription (promoters, enhancers, insulators, etc) by affecting where proteins bind DNA ... | [
"In decoding genes, there is a process called transcription, that creates a copy of our genes (which are in the format of DNA) into a much more 'portable format', if you will, which is mRNA. It is known that eukaryotic mRNAs undergo a post-transcriptional process called alternative splicing. ",
"Alternative splic... |
[
"If you were to release a liquid somehow in a cube shape, what would happen? Would it retain its shape, or spread?"
] | [
false
] | Just wondering? | [
"It'd splash all over the floor if there was gravity present. But I'm guessing you mean in the absence of gravity? If it's a normal liquid, it has surface tension. So if you released it, it'd contract into a sphere, since that minimizes the surface area. "
] | [
"Oh right! I've been trying to work out what would happen over the last few days (Not studying science, so I didn't come to a solid conclusion)",
"Thanks!"
] | [
"Well, 'surface tension' is the macroscopic phenomenon. The way it works at the molecular level is fairly simple though. The molecules in a liquid form intermolecular bonds with each other, they're attracted to each other. So a molecule of a liquid will have the lowest energy when it's surrounded by its fellow liqu... |
[
"Does \"thinking hard\" burn more calories than normal thought?"
] | [
false
] | null | [
"Here's some previous answers:",
"http://www.reddit.com/r/askscience/comments/kjwes/does_thinking_require_calories/",
"http://www.reddit.com/r/askscience/comments/j8lau/is_it_possible_to_burn_calories_as_if_you_were/",
"http://www.reddit.com/r/askscience/comments/fjndk/does_thinking_harder_burn_more_calories_... | [
"I didn't bother searching on that one because I was so certain I was the first to think to ask it. Ohhh the hubris!"
] | [
"Over what time scale?"
] |
[
"What evidence is there that electrons literally orbit the nucleus?"
] | [
false
] | As I understand it, electrons have different energy levels which we call atomic orbitals. How do we know that the electrons are literally moving around the nucleus? | [
"They aren't, at least not in the same way the Earth orbits the Sun. It's taught as such because it's a comforting inaccuracy that still allows students of chemistry or physics to make many physically meaningful calculations without mucking about with the insanity that is quantum mechanics.",
"Electrons are a sm... | [
"The observation came first, then the theory. ",
"Balmer found that hydrogen emission occurred at specific wavelengths and developed an ",
"empirical formula to describe it",
". Bohr then developed a ",
"model",
" that postulated that electrons circle the nucleus in discrete orbits. Using this he derived ... | [
"The reason the Bohr model works is that it correctly predicted that angular momentum and energy are quantized, even if it didn't quite understand that position and momentum of the electron can't be well defined in the atom. "
] |
[
"Theoretically speaking if we tried to colonize Mars would we succeed and how long will it take until it is habitable for humans, animals and plants?"
] | [
false
] | [deleted] | [
"No physical limitation, only an engineering problem.",
"I think that could be a motto for the entirety of humanity's scientific and technological accomplishments."
] | [
"No physical limitation, only an engineering problem."
] | [
"Problem?"
] |
[
"What is the fireball of a nuclear explosion composed of?"
] | [
false
] | I assume it isn't the bomb itself due to the sheer volume of it. | [
"The 'fireball' from the explosion is from the surrounding matter which has been vaporised by the energy released from the fission.",
"The nuclear fission releases ",
" energy in gammas and x-rays (and kinetic fission fragments and neutrinos and neutrons). This energy get absorbed by the surrounding matter (ro... | [
"Materials scientist here. I wanted to correct you on one thing, a candle is most certainly not a plasma. Plasma is a state of matter in which particles are in a highly energized state (ionized), this typically requires a larger amount of energy that a candle cannot provide.",
"Plasma is electrically conductive... | [
"Just another FYI - the reason candle flames glow is not because they create a plasma, but because there is a continuous stream of soot particles that the combustion reaction heats up until they glow due to blackbody radiation. The soot particles continue to react with oxygen and shrink the further away from the w... |
[
"What would happen if you forced two opposing magnets together?"
] | [
false
] | [deleted] | [
"Eventually the magnetic moments of the atoms within the magnets would re-align to make one bigger magnet. You can observe this happen in real time if you hold a really string magnet in the \"opposing\" configuration to a smaller magnet.",
"I don't know exactly what would happen if you had two perfectly symmetric... | [
"Would heat build up? "
] | [
"That was my thought. Eventually a quantum fluctuation rather than a thermal one breaks the symmetry."
] |
[
"Why is it easy to remember melodies from songs, but not the lyrics sung to the same melody?"
] | [
false
] | null | [
"Our brains evolved to recognize and predict patterns in the world around us. The cortex is particularly adept at this and has been the inspiration behind ",
", most often used as pattern recognition systems.",
"Recognizing patterns with a temporal dimension to them is beneficial across most of our senses. If... | [
"\"BTW: I claim no authority in the field of psychology, I'm just share an interest in it and formulated a semi-educated assumption.\"",
".... which is precisely what this sub is not for."
] | [
"\"BTW: I claim no authority in the field of psychology, I'm just share an interest in it and formulated a semi-educated assumption.\"",
".... which is precisely what this sub is not for."
] |
[
"What does the pOH tell you about a solution where there is no hydroxide?"
] | [
false
] | Okay, it was hard to make a title for this one, but I'll try to clarify here! If we have the following reaction: HCl + H2O → H3O + Cl Let's say the pH for this solution is 1.7. Using Kw(10 molars ) = [OH ] * [H3O ] log([H3O ] * [OH ]) = log[10 ] log[H3O ] + log[OH ] = log[10 ] -log[H3O ] - log[OH ] = - log[10 ] pH + pO... | [
"As long as you are working with an aqueous solution, the Kw expression is valid. In another solvent, that wouldn't be true. ",
"However, in the expression above, your determination of the concentration of hydroxide is correct. Even if there is a lot of H",
" around, that doesn't mean there can't also be OH"... | [
"Water naturally dissociates into hydronium and hydroxide ions.",
"2 H2O <--> H3O",
" + OH",
"So even if you start with, say, a liter of pure H2O, some of those water molecules steal hydrogen ions from other water molecules, creating hydronium and hydroxide ions. As the concentration of H3O",
" and OH",
"... | [
"Thanks for the clarification!"
] |
[
"Does the insulin/insulin-like signaling pathway have different roles in different organisms or groups of life?"
] | [
false
] | Or does it seem to universally perform the same ultimate functions for all life? Insulin-like signaling seems to be a very ancient, conserved, and ubiquitous pathway. I'm wondering what, if any, differences in its function may have arisen in response to the varied environmental pressures that different groups of life w... | [
"To my knowledge insulin and the insulin-like growth factor signalling pathways are strongly conservd across all animals. Here is at least one paper on this",
"https://www.ncbi.nlm.nih.gov/pubmed/11943559",
"Because insulin is critically involved in fat deposition you should expect that insulin functioning is s... | [
"Life is so broad that until an expert in the insulin pathway comes along, I'm going to have to supply a limited answer. In Drosophila and C. elegans there is ",
"strong conservation of the pathway, protein structure, and function",
". This already covers a pretty remarkable breadth of animal life. To quote fro... | [
"Like I said to the other guy, thanks for taking the time to respond. Much appreciated."
] |
[
"How are the assembly languages for different processors turned into higher level programming languages like C?"
] | [
false
] | I understand the highest level programming languages are written in lower level ones, (ie. java is written in C), but what handles converting C to assembly? Is C rewritten for different processors? | [
"A compiler is typically viewed as having three stages:",
"Note that what most compilers generate is machine code, and ",
" assembly. Assembly itself is a language; just simply one that has a roughly 1:1 mapping between assembly instructions and machine code, as a way to make it much easier to program than hav... | [
"A ",
"compiler",
" is what is used and is a complicated subject. When a new computer processor is created, a cross compiler is made that runs on an existing processor which creates the machine code for the new computer processor. Using ",
"the LLVM project",
" it is possible to make dozens of languages wo... | [
"A correction: Most compilers do always generate assembly code, or a low level representation that is very close to assembly code, but most modern compilers will silently and seamlessly hand that off to the system assembler (and then linker) so the user only has to invoke one program. ",
"For example, GCC produce... |
[
"Would spreading sugar on an icy path have the same effect as spreading salt on it?"
] | [
false
] | null | [
"Sucrose in anything but nanoparticles dissolves very frustratingly slowly into liquid water at low temperatures, and even slower into ice that it's sitting on the surface of.",
"That said, sucrose-water solutions do lower the freezing point of the solution, and the saturation of the solution controls the amount ... | [
"Do you want ants? Because that’s how you get ants"
] | [
"This has the advantage of making the surface annoyingly sticky as it dries."
] |
[
"How do antibiotics work and how do doctors know which to prescribe to you?"
] | [
false
] | Anyone know? | [
"Bigbuddha is correct - different antibiotics have different mechanisms. The broader point is that because bacteria are quite far removed from us evolutionarily, so any chemical that can disrupt essential processes of bacteria without messing up the analogous process in our own bodies is a potential antibiotic.",
... | [
"Its basically depends on the antibiotic or the bacteria.",
"Some antibiotics break down the bacterias cell wall (which causes it to die when it replicates) others prevent them from making energy so they just die from lack of nourishment."
] | [
"Antibiotics have different mechanism based on the type:",
"The beta-lactams: This includes the penicillins and the cephalosporins as the major groups. These work by preventing the cross-linking of bacterial cell wall components. Since the bacterial cell wall is constantly under construction and deconstruction, p... |
[
"How much weight can a person lose by fasting for a month?"
] | [
false
] | null | [
"Well, if their bmr holds steady at 2,000 calories a day for 30 days, and there's no exercise, that's 60,000 calories in a month / 3500 calories per pound of fat = ~17 lbs.",
"But. the body will not only be degrading fats, there will be loss of muscle as well (which is how the body decreases bmr, after all, by sc... | [
"Please don't tell me you're asking this because you want to try."
] | [
"Nope. Though a lot of people fast for religious reasons and such."
] |
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