title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Can someone please further clarify the process of muscle protein synthesis for me?"
] | [
false
] | As I understand it (and I appreciate much is missing from this): We workout, create damage to the muscle, and eat a protein dense meal. The protein is broken down into amino acids, to which they are then signalled by satellite cells on the damaged muscle to be synthesised into new proteins. The proteins are then synthe... | [
"The molecular mechanisms underpinning resistance training-induced skeletal muscle hypertrophy are not entirely elucidated. We know a lot, but not enough.",
"There are a number of stimuli pertinent to resistance training that stimulate hypertrophic growth. You have mechanical tension, metabolite accumulation and ... | [
"Even as a molecular biologist, I had trouble following all that verbiage."
] | [
"Oh heck yes! Something in my specialty! ",
"Proteins of the sarcomere are monitored pretty closely for a loss of integrity/proper shape. When a protein in the sarcomere becomes damaged, two teams of factors can respond. 1) Chaperones that recognize and refold the damaged protein (if it’s possible). If successful... |
[
"Is there any interesting chemistry that happens with Lanthanides/Actinides?"
] | [
false
] | I've never seemed to really talked about any chemistry that happens in this block of elements in any of my chemistry courses. What sort of chemistry goes on with this block? | [
"The lanthanides all have at least one stable isotope with which it is relatively easy to do chemistry. The early actinides are also only slightly radioactive (Think half-lives on the order of millions of years), so those can also be looked at with fairly minimal concern for health. ",
"With regard to OPs questi... | [
"This is very late but Lanthanides have luminescent properties and are used in those areas. The research group at my university that looks into them is fairly extensive. They mainly look at synthesizing complexes using metals in this group and then optimizing them to get the exact fluorescence they want. They are t... | [
"Better late than never! That's actually exactly what I wanted to know and I'd love to read more. If you don't mind answering, what research group or university studies this?"
] |
[
"Why is it sometimes when i am falling asleep, i suddenly very violently jerk back awake?"
] | [
false
] | Is this something normal? What exactly is it? What causes it to happen? Its difficult to explain, but i will be falling asleep, concentrating on something. Like what my plans for tomorrow are. I feel myself getting to that very drowsy state just before sleep and then all of a sudden this extremely violent jerk wakes me... | [
"http://en.wikipedia.org/wiki/Hypnic_jerk"
] | [
"That's the kick. When experimenting with sleep aids, you will want to use one that preserves the feeling of balance in your inner ear."
] | [
"These are know as myoclonic jerks or hypnic jerks and are, most of the time, perfectly normal. ",
"http://en.wikipedia.org/wiki/Hypnic_jerk"
] |
[
"Could someone be born with YY chromosomes? What would be the result?"
] | [
false
] | null | [
"No, you couldn't. Aside from the fact it's pretty much impossible naturally (females are XX, so the eggs can't have Y chromosomes), it wouldn't survive because of the large number of crucial genes on the X chromosome."
] | [
"I think the closes thing that can happen is a trisomy of the sex gene leading to this ",
"http://en.wikipedia.org/wiki/XYY_syndrome"
] | [
"Responses like this are inappropriate for this subreddit."
] |
[
"I believe I know what happens when you die. Opinions on this?"
] | [
false
] | null | [
"Heading there now, thank you."
] | [
"This probably belongs on ",
"/r/AskScienceDiscussion",
", since it is quite speculative."
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"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."
] |
[
"Claim about Hydrogen Peroxide and Cockroaches"
] | [
false
] | This is something I heard a long time ago from someone or something that, in my mind, was fairly reputable. But I've since tried to look it up and cannot find any support for this claim. It's a claim I may partly mis-remember; I'm not even sure if this particular combination of chemical and insect were the ones referen... | [
"I heard that Diatomaceous Earth does what you are talking about. It's like a powder that has sharp edges (under microscope). The sharp edges get into joints(soft areas) of insects with exoskeletons, and it basically cuts them up when they move. They say it's not harmful to humans.",
"Here is a link:",
"http://... | [
"It's harmful to humans if you breath it. It billows up into the air a bit when you pour it out."
] | [
"I know that hydrogen peroxide is an oxidizing agent, as it can split into water and an oxygen anion regularly. However, I don't know what substance makes up the joints of cockroaches. Oxidizing agents are often harmful to biological systems, so it is feasible that H2O2 would have an adverse effect."
] |
[
"How did the planets get in orbit around the sun?"
] | [
false
] | I understand the basics of orbital mechanics...that planets are constantly "falling" into the sun, but have enough horizontal velocity to miss it. What I don't understand is how the planets ever got that exact amount of horizontal velocity in the first place. If they were too slow, they'd fall into the sun. If they wer... | [
"The formed from the same rotating cloud of gas that formed the sun."
] | [
"The solar system formed out of a cloud of material. As things started clumping together and rotating around the center mass (the sun) the planets began forming. This is called accretion. The protoplanetary disc cleared out as accretion continued. They all have the right velocity because they formed from a disc sur... | [
"Couldn't the protoplanetary disc out of which the planets were formed have just as easily condensed into planets with wildly different horizontal velocities?",
"No. There would have to be some sort of strong external forces at work to cause the protoplanetary disc to begin having wildly different rotational velo... |
[
"Could a solar storm knock out all our electrics? And what would be the practical consequences?"
] | [
false
] | I've heard that something like this -- -- could stop electric devices working all over the world. If this happened, would the devices be permanently destroyed or only cease to work during the storm? What other consequences could we expect? | [
"Five hours ago",
"."
] | [
"Damn, synchronicity. This is like that time when ",
" and ",
" came out in the same year."
] | [
"Or more likely, both you and the other person who asked watched the same television programme, or such like.",
"This happens here about four times a week, I'd estimate."
] |
[
"Is sugar unhealthier when refined?"
] | [
false
] | My mother keeps telling me that white sugar is "bleached" and contains bad chemicals and whatnot. Is there any scientific basis to support that refined sugar may be worse for your health than unrefined varieties? (Say, because of residual refining agents.) | [
"In fact, almost all brown sugars are made by adding molasses to refined white sugar, so as to more carefully control the resulting product. It will contain the same residual chemicals as white sugar. Unrefined sugar such as ",
"muscovado",
" is considerably harder to come by (YMMV. Try organic food stores).",
... | [
"Sugar its self is a poison. ",
"What? Sugar is glucose or fructose. The second most important purpose of your body is to keep your blood glucose level high enough to keep your brain alive. It's definitely not poison."
] | [
"Sugar its self is a poison. ",
"Could you elaborate?",
"EDIT:",
"Sugar is only a poison in the same sense Water is a poison, consume too much and it can kill you. ",
"In NO OTHER SENSE is Sugar a Poison in the Technical and Scientific Sense."
] |
[
"So how do our bodies actually process sunlight into vitimin D?"
] | [
false
] | Like, photons are waves. How does that energy become usable to us? Denaturing materials already present that turn into vitimin D? Or is it simpler? | [
"It's basically what you said. You have a type of cholesterol hormone, 7-DHC, in your skin that is converted to cholecalciferol by UV radiation from sunlight. The cholecalciferol travels through your bloodstream to your liver where its metabolized to another product (25(OH)D), and this molecule then gets metabolize... | [
"Sunlight (specifically UV light) is used as a source of energy for part of a series of reactions converting cholesterol to vitamin D₃.",
"The full pathway consists of a few more intermediates, but the idea is that the energy is used to convert one molecule to another, which puts it on the path to becoming vitami... | [
"Thanks for your great answer. I'm curious about the next part, what actually is it that vitamin D does in the body? Does it get absorbed into the bones and increase bone density by getting calcium from the bloodstream to bind to it?"
] |
[
"Why do stimulant drugs weaken your heart? If raising your heart rate through exercise strengthens your heart why wouldn't drugs do the same?"
] | [
false
] | null | [
"Because overusing your acetylcholine receptors in your brain causes wear and tear on the rest of your body. Your heart is just a really incredibly strong muscle and like every other muscle it needs the right chemical signals and nutrients to function. Stimulant drugs make your heart beat faster and harder so it al... | [
"Because when you exercise the fast heart rate and harder work its doing is because it needs extra blood flow for you to move around. With drugs it just does that as a secondary effect. I can give you some sources here on what using cocaine foes to your heart! ",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6387... | [
"Could you elaborate more on the difference between stimulants and exercise for your heart muscles? In regard to:",
"stimulant drugs make your heart beat faster and harder so it also puts a lot of PHYSICAL stress on the heart",
"Being physically active also makes your heart beat harder and faster than just bein... |
[
"Ask Anything Wednesday - Engineering, Mathematics, Computer Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"Most calculus students spend several years in classes that progressively build one skill on top of another. This is the key: each new skill is not hard, but each skill builds on previous skills. If the student misses one critical skill in math, the rest of it really is difficult or impossible to fathom. I did st... | [
"Thanks to Euler's formula, pretty much everything involving waves. e",
"= cos(θ)+i*sin(θ). Electromagnetism for example would include pretty difficult if not impossible math without imaginary numbers."
] | [
"Can I add to this? ",
"",
"I was never fond of math, not in the sense that I didn't appreciate it, just that it seemed like a bunch of formulas that I was memorizing but unable to actually apply to anything. EVERYTHING changed when I took Calculus I in college. Instead of learning how to solve for Y in a comp... |
[
"How is the Observable Universe 90 billion light years across when the farthest known Galaxy is 13.2 billion light years away?"
] | [
false
] | The Galaxy EGSY8p7 is the farthest known object in our Universe at 13.2 billion light years away. We say that the Observable Universe is 90 billion light years in diameter. Is this our simulation with data we have like expansion of space etc or is it really 'Observable'. I'm getting confused as to why its termed Obser... | [
"13.2 Gy is the time it took light to travel to us, while the current proper distance from the galaxy is around 45 Gly, because the Universe has expanded significantly in the meanwhile over 13.2 Gy, as the light travelled"
] | [
"Table you linked reports redshift and ",
", not comoving distance.",
"So can I infer that we can use scopes to view Galaxies right now that are 42Bly away? ",
"Move that \"right now\" to the end of the sentence."
] | [
"what do you mean \"appear like it's a certain distance away\"? Nobody claimed it \"appears like\" it's 40 Gly away. It ",
" 40 Gly away in comoving coordinates."
] |
[
"How does the body choose its preferential temperature?"
] | [
false
] | Like say the shower is “too hot” for me but is “warm” at best for somebody else. Is it purely our choice as the individual? Or are there factors that impact this “preference”? | [
"Our perception of temperature is extraordinarily subjective. For a start, whether we're feeling hot or cold is relative to what temperature we were before.",
"There's a simple experiment you can do at home to prove this",
"; get three bowls of water, one ice-cold, one room temperature, and one hot. Put one han... | [
"I used the hypothetical shower because it was a real shower this morning that sparked the thought. I like taking a warm shower. Not hot. Not cold. Just warm shower. Fiancée also likes warm showers. Difference is, when I got in the shower as she was getting out, the shower she was taking was somewhere near the temp... | [
"Reminds me of the boiling frog fable - if you put a frog in boiling water it'll jump out but if you slowly heat the water it'll just die."
] |
[
"I've heard/read some crazy conspiracy theories that cancer and/or aids were made by humans and not nature. Is there any evidence at all that supports this or indicates that it is possible?"
] | [
false
] | null | [
"No"
] | [
"The burden of proof is on the person making the claim. I have never heard of any such scientific evidence."
] | [
"Thanks. So pure hogwash? NO evidence that could even hint that it would even be possible?"
] |
[
"Would changing the oxygen % in the atmosphere change our life expectancy?"
] | [
false
] | I heard aging explained as "rusting", as in, damage caused by oxygen, which wears out the body. On the other hand according to (sorry, couldn't find the paper itself), lack of oxygen appears to be connected to tumor growth. So, could we affect our longevity by fiddling with the oxygen content?(assuming that kind of atm... | [
"Loads of relevant info in these threads."
] | [
"The blood/hemoglobin system does an excellent job of buffering the O2 delivered to the cells. So huge differences in atmospheric O2 levels only slightly effects the amount of O2 delivered to the tissues. O2 saturation is maintained around 95-97% in a normal human.\nPlus as soon as you lower the O2 level the body w... | [
"Sure, or Biosphere-style experiments could be done with different atmospheres."
] |
[
"How would everyday electronics behave in space?"
] | [
false
] | Thought about this today after seeing pictures taken on the moon. Basically, if someone took a smartphone or a DSLR camera into space, would anything happen to it? Would they crack and break, or would they simply float around? Also, are electronics/computers used in space/on the ISS physically designed to work in space... | [
"First, I work as an Industrial Designer and mechanical engineer and have designed various packaged electronic devices for space applications (gas detectors, satellite communications transceivers, ISS manipulator arm parts) as well as for use in earth based vacuum chambers (medical laboratory test devices).",
"In... | [
"Lots of regular electronics, from cameras to iPods, function in space...",
"Some modification to many electronics is required, though. For iPods, this entails removing their lithium ion batteries because they're a potential safety risk. When the batteries (Lithium Ion) fail, they can (although rarely do) fail sp... | [
"Chris Hadfield is his full name"
] |
[
"Is this real, and if so, does anyone know what it is?"
] | [
false
] | I came across this picture... I just wanted to know if anyone knew if it was real, and if so, what is it? | [
"http://en.wikipedia.org/wiki/Glaucus_atlanticus"
] | [
"No, ",
"r/science",
" sucks. You love ",
"r/askscience",
"."
] | [
"Oh wow, ",
"I posted a picture of one of these in r/Pics over a year ago asking what it was",
". The closest answer was that it was some type of nudibranch but I never got a more concise answer.",
"Thanks."
] |
[
"Are film grain and digital noise caused by the same thing?"
] | [
false
] | So I get that film grain is caused by larger silver particles in higher ISO films, but digital noise is also caused by high ISO. Is this just a coincidence? Not sure what to tag this with so I'll just go with physics. | [
"They’re separate phenomena, but the concept is the same.",
"ISO is a measure of light sensitivity. In the analogue times, higher ISO was created by making the grains larger. In that way less light was necessary to have that silver grain express. ",
"In digital photography, it’s not the size of the detection me... | [
"Thermal noise is a component, but photon shot noise dominates a lot of digital photography."
] | [
"The noise in digital cameras has an analog origin. The raw signal is analog and must be amplified, sampled and digitized to make a digital image. The noise is called Johnson-Nyquist or thermal noise, and it is present in all circuits. It is usually only a problem when weak signals need to be amplified by high gain... |
[
"Theoretically, what would the Earth look like today if we didn't have the moon?"
] | [
false
] | It helped balance our planet from a more unstable wobble than our current Chandler wobble, it moves tides, and many more things I can't name off the top of my head (unless I named them all ahah). But what if it never existed? would the Earth be this green planet we see today with life? or would it be this barren rock w... | [
"This video",
" says it better than most could - in short: ",
"This also reminds me of a ",
"recent podcast",
" that explores the opposite, what would happen if we have two?"
] | [
"Early moon was VERY close, resulting in VERY high tides, washing miles inland.",
"Tide brought minerals from land into the depths.",
"Those minerals, plus the heat of subsea vents were the trigger of life.",
"No moon, no life.",
"(Following Giant Impact Theory)"
] | [
"It's not that the tilt is worse, it's variable on a much shorter timescale than earths. That would conceivably be a problem for the adaptation of complex life.",
"Imagine if Australopithecus evolved in the jungle. At that stage were a few million years from present day. but 1 million years later the planet is on... |
[
"Does calorie restriction inhibit healing?"
] | [
false
] | I'm curious if moderate calorie restriction has any inhibitory effect on tissue and bone regrowth. Assume that the restriction is not severe (something like sub 500 of BMR) and the supply of micronutrients is sufficient. It seems pretty clear-cut that nutritional deficiencies would inhibit the body's repair work, th... | [
"Also, does calorie restriction inhibit or change brain functions? Just wondering, as I do believe that my thought patterns change when I suddenly go for a long time without eating."
] | [
"We're very familiar with the fact that malnutrition significantly impairs wound healing, but I don't think there has been any research on the wound healing effect of temporary calorie restriction in humans who aren't otherwise malnourished. ",
"This study",
" in lab rats does show an impairment in wound heali... | [
"A long term \"starvation\" condition causes the brain to run primarily on ketone bodies. These ketone bodies are synthesized by the liver from fatty acids. Nearly all other types of cells can use fatty acids for energy directly, but fatty acids can't pass through the blood-brain barrier. The shift in primary brain... |
[
"Why must we sleep?"
] | [
false
] | Why must we sleep? Why can we not just continuously consume and keep using energy? I have always wondered this. It just seems like we would be able to just keep eating and keep going. | [
"Science has not come to a conclusion as to why we, or any other animals for that matter sleep. There are ",
"multiple theories",
" but no solid conclusions. "
] | [
"Someone already answered with a wiki link, but here's some better sources on the topic:",
"These questions have been pondered endlessly by physiologists and psychiatrists (and philosophers). Parkes has reviewed the main theories—body restitution, facilitation of motor function, consolidation of learning and memo... | [
"arumbar and d0peamine have both given a rather concise summary of the state of things - we don't have a definitive answer as to why we require sleep.",
"However, we do have some ideas, and we know that it's not a matter of simple energy usage in some gross metabolic sense. We have a pretty good idea that its pri... |
[
"What happens to all of the energy in a lightning bolt when it strikes the Earth?"
] | [
false
] | null | [
"First of all the energy isn't \"in\" the bolt, the bolt is a sort of temporary wire between the earth and a cloud. The energy is in the imbalance of charge between the cloud and earth. A lot of the energy goes into ionizing the air. It takes a lot of voltage to separate electrons from the molecules in the air. ... | [
"(Slightly off-topic)Also, the ionised nitrogen in the air bonds with water to create nitrates and ammonia, helping to fertilise the soil."
] | [
"Or it can bond with oxygen and form ozone, giving lightning the smell of, well, lightning."
] |
[
"What about spermatogenesis requires lower temperatures?"
] | [
false
] | Is there some fundamental reason that many species have to place their testicles outside their body for spermatogenesis to occur? Why couldn't life evolve to create them at the two degrees Celsius higher body temp vs. scrotal temperature? Surely there must be a good reason for placing something as incredibly important ... | [
"It is injected into a woman's 37 degree body and can live for up to 3 to 5 days. I don't think that's it. The congealing effect on exposure to heat has nothing to do with the sperm either, that's an effect of the proteins in semen, not the sperm themselves. Those ingredients are added right at the moment of eja... | [
"\"Proteins in ejaculate can denature (change shape and lose function) when exposed to warmer temperatures.\nThis is most obvious in hot showers when ejaculate can congeal into a thick glue like substance.\"",
"This is wrong. While I'm sure there are proteins that denature at such temperatures (none in the human ... | [
"I can't give you a conclusive answer, but I do know that mutation rates are higher when temperatures are higher. Since it's vitally important to keep sperm from mutating or deforming if you want to have normal offspring, then it would make sense to produce them at lower temperature. Evolution seems to have selecte... |
[
"Does the heat of a conventional explosion reaches the same height as the heat of a nuclear explosion of the same yield?"
] | [
false
] | [deleted] | [
"The overpressure from a nuclear explosion is caused by the superheated expansion of the surrounding atmosphere due to the 10",
" °C temperature of the fission/fusion event. ",
"In the case of a conventional chemical explosion, the overpressure is caused by the sudden, rapid expansion of the hot, gaseous produ... | [
"In addition to what's already been said, you can actually estimate the ratio of the maximum temperatures (to within about an order of magnitude or two), just by comparing ratios of the specific energy densities in each type of explosive.",
"There will be some error involved in this calculation, as the explosion ... | [
"There are two temperature producing events in a nuclear explosion. First is the fission reaction itself, heating the core to the 10",
" C. But that core radiates a tremendous amount of soft Xrays, which then heat the surrounding air to incandescence at many thousands of degrees. And is the primary driver of the ... |
[
"What happens when I mentally phase out & is it a bad habit?"
] | [
false
] | null | [
"As what I imagine is a related follow up question: could anyone comment on why stimulants help increase focus even when sleep deprivation is not a factor? "
] | [
"Possibly related: are there studies on vipassana meditation?"
] | [
"That is definitely relevant."
] |
[
"How does a pacemaker work?"
] | [
false
] | null | [
"Hi there.",
"First, it helps to understand how your heart works. Some of the cells that make up your heart are able to create electrical impulses. These impulses are what cause the heart to contract. In a \"normal\" heart, these impulses are triggered by these cells in at very regular tempo, or \"pace\".",
"Th... | [
"Not a physician but yes, those pacemakers do exist and are called rate-responsive pacemakers. They can sense increasing activity because they have built in (depending on the type) vibration sensors using a piezo-electric crystal or through impedance (a measure of electric resistance). The sensors will automaticall... | [
"That's really interesting. So for a person with a pacemaker, is their heart rate always the same? For example when a person gets excited or exercises, their hr speeds up. Does a pacemaker mimic that to get the increased blood flow that is needed in certain situations?"
] |
[
"How feasibly could human beings cause mosquitoes to go extinct?"
] | [
false
] | I remember reading a study a while back that said there would be virtually no damage to the ecosystem if mosquitoes were eradicated. How realistically achievable is the outright eradication of the mosquito species? | [
"As already mentioned, any article claiming that removing a species from an ecosystem will cause virtually no damage to said ecosystem is completely bogus. Ecosystems are highly interconnected systems and you cannot removal a single part of it without changing every other component as a result.",
"Anyways, it is ... | [
"I believe that ",
"only a small minority of mosquito species act as a vector for human malaria",
" Would removing ",
" specifically likely have a major ecological impact if the other 98+% of mosquitos are left alone? Or even just removing the small proportion of ",
" species that act as a vector leaving th... | [
"You bring up some very good points and questions.",
"It's important to remember that malaria is not the only disease spread by mosquitoes. ",
"Other diseases",
" include various types of encephalitis, Dengue fever, and Yellow fever. Some of these diseases are caused by viruses so I'm not sure if you can simp... |
[
"Is all computer processing just math?"
] | [
false
] | So in no way shape or form do I have an extensive knowledge of computers, but one thing I've always been intrigued with is how a puny little microchip can do so dang much. I tried looking up how processors work, and i got into some detail on AND and OR gates and what not, but the websites i found only explain how these... | [
"I don't know everything to the tiniest detail about it, but I do have a fair bit of understanding there.",
"CPUs(processors) use AND, OR and all those gates to manipulate data (all the input) and give feedback (output). Math problems are just one of the examples of what a CPU can do using those gates. Clicking o... | [
"On the most basic level, a computer is a collection of logic gates - these take advantage of semiconductors to cause 2 given inputs to give a specific output. For example an AND gate only gives an output voltage when both the inputs have voltage (inputs A AND B are on).",
"From the logic gates we can build machi... | [
"There are many levels of abstraction between logic gates and graphical user interfaces, so it's not really viable to describe this transition directly. What you can do is try to understand it step by step. ",
"You might have read that a processor works by executing machine code, which consists of simple discrete... |
[
"Golf balls are said to be dimpled to reduce drag. If that’s true, why aren’t aeroplanes dimpled?"
] | [
false
] | null | [
"So the nature of flow around objects is a fairly complicated topic, and the first thing you have to understand is how it changes based on:",
"These three quantities combine to one dimensionless number known as the ",
" which is a good indication of the kind of flow patterns you're likely to see. The Reynolds n... | [
"While aeroplanes might not benefit from dimples, they benefit from scales.\n",
"There have been tests",
" where plane was covered with film with shark like skin pattern and it reduced drag and thus fuel consumption (by 1.1%)."
] | [
"So this is what my PhD is in. The article you linked does not indicate how they actually calculated this 1.1%. The video shows they did some form of full body experiment but still no indication of the measurement process. A simple \"stick it on and measure fuel consumption on one flight with and one without\" is n... |
[
"By my count, there are 32 nearby celestial bodies that have achieved hydrostatic equilibrium. Using both imagination and knowledge, how can we colonize them all?"
] | [
false
] | [deleted] | [
"Io is waaaay too active.",
"Sun is too hot. see how hot it is here on earth? even hotter on the sun, believe it or not.",
"Mercury doesn't seem like a good choice, it has a very elliptical orbit for a planet and 3:2 spin:orbit coupling, which means very long \"days\" and \"nights\". also, no current atmosphere... | [
"Well to rule out a few right off the bat there;",
"The Sun - Can't colonize a nuclear reaction, nothing will last and it doesn't have a hard surface for ground of any sort",
"Jupiter - Has no ground, its just gas all the way through the core. Moons are fair game and should definitely be treated separately as e... | [
"For these bodies, I was envisioning more of a floating colony. Perhaps some kind of paneling or device along the bottom that transfers radiating heat from the planet/star below into some sort of gravitationally-oppositional force.",
"I knew that establishing a settlement anywhere near the sun would seem a bit to... |
[
"How did chaperone proteins evolve?"
] | [
false
] | What function could they have possibly served before they achieved their current function? I'm so confused, yet fascinated by their existence. | [
"I imagine the same way as everything else at that highly complex level. I am afraid I am not knowledgeable to go into massive detail.",
"Two things I am reasonably certain of:",
"Many chaperone proteins are frequently referred to as 'heat shock proteins', allowing protein folding to occur at higher heats. Many... | [
"I know how evolution works which is what made me wonder what purpose these proteins may have had before they took over the function of allowing other proteins to properly fold. I appreciate the reply though =)"
] | [
"Well it is askscience, detail is good and you never know the scientific background of the person asking. ",
"The proteins may or may not of had any function before they started helping proteins to fold. While it is entirely possible they 'swapped' from a similar protein, the genetic mutation would mean you would... |
[
"How far are we from having artificial knees that are equal to/better than real knees?"
] | [
false
] | Are we ever going to have artificial knees that are anywhere near as good as artificial hips are now? I understand that the hip is a fairly simple joint, do we just not have a good enough understanding of the knees mechanics? Full disclosure: I'm a basketball player who's slowly ruining his knees and fantasizes about r... | [
"Currently tissue engineered articular cartilage knee replacements are in pre-clinical trials in animal studies. Menisci are at a similar stage but showing greater success. Much of this current work is largely unpublished due to academia-industry collaborations (industry does not like to publish results until they ... | [
"I don't know a whole lot about orthopedics, however, this is the big question in much of regenerative medicine. My guess, working mostly with regenerating soft tissues, is that repairing/replacing diseased organs is going to be first and best accomplished by stem cells and/or tissue, cellular, or molecular enginee... | [
"I know I'm asking you to speculate wildly, but what do you think will happen first: technology develops that allows polymer-alloy hip/knee replacements to be just as good as the natural bone (i.e. you can run/ play contact sports/ fall etc. etc with them), or technology develops to engineer the cartilage/bone to m... |
[
"The Schwarzschild radius of the observable universe is roughly the size of the observable universe. Is there any significance to this?"
] | [
false
] | The has several estimates for both mass and radius of the observable universe. Depending on what values you use you can get a Schwarzschild radius that is either bigger or smaller than the estimate for the size of the observable universe but in any case it's within a couple of orders of magnitude. Is this just a coinci... | [
"Sean Carroll has a decent blog post about this ",
"here",
". The basic statement is that this is what you expect for a universe that is (at least very nearly) spatially flat."
] | [
"Less than an order of magnitude difference. I'm pretty sure our uncertainty about the mass of the observable universe is greater than that."
] | [
"You have struck upon one of the most elegant conclusions of astrophysics imho. To date the universe appears to be flat within measurement error. If the universe is ",
"flat",
", then it follows that the visible universe will have a radius equal to its Schwarzschild radius.",
"It further follows from the deri... |
[
"How would you measure the mass of a balloon full of helium at one atmospheric pressure?"
] | [
false
] | If you knew the mass of the uninflated balloon and how many moles of helium were going into it, I imagine this would be relatively simple, but for the sake of science, assume that we don't know these things. | [
"It actually would not be too difficult so long as you had a way of measuring it's lift (the force of the balloon pulling upwards) and a way to accurately measure it's volume (I assume some kind of large graduated cylinder could work.) Buoyancy is measured thusly: F(up) = g * (mass of displaced air - mass of object... | [
"Put something in orbit around the balloon, then measure the period and semimajor axis. Note: this will only work for very large balloons."
] | [
"The buoyancy force (how much the balloon can lift) is the difference between the weight of the balloon and the weight of the displaced air. Assuming you know the volume of the balloon and the density of air you can get the mass of the balloon+helium from:\nm_balloon = rho_air*V_balloon - F_buoyant/g"
] |
[
"Could you create a controlled-gravity environment and if you could would it be possible to train in higher levels of gravity and be less affected by Earth's gravity?"
] | [
false
] | So pretty much, can you do what they did in Dragon Ball Z to get stronger? | [
"You have a few options, all of them ridiculously expensive:",
"A centrifuge.",
"A really powerful elevator in a really tall building with good brakes at the top.",
"A quickly accelerating train.",
"A quickly rising airplane or rocket ship."
] | [
"As far as the skeleton is concerned it would be akin to the problems that overweight people have on many important joints, specifically the knee joint and the spinal column. ",
"As far as the heart becoming stronger, yes that is a possibility, but it might simply just task that heart too much. Not all exercis... | [
"buy a fat suit. Wear it everywhere."
] |
[
"Is there anything to claim that adding a drop or two of water to scotch \"opens up the flavor\"?"
] | [
false
] | I find it hard to believe that such a miniscule amount of water could noticeably change the flavor profile of a glass of scotch, yet consumers of fine scotch everywhere tell me to put a drop or two of water in the glass. Reddit, am I unnecessarily watering down my scotch? | [
"Wait if you can't tell the difference why wouldn't you water down your scotch until you can tell the difference? You're essentially increasing your volume of scotch without sacrificing taste."
] | [
"If it works, then you should be able to test with and without the water, and taste the difference. Do a ",
"blind test",
" and see. If you can't tell the difference, then you can stop watering down your scotch."
] | [
"Yes.\nHere's an excellent blog post on the subject. They also link to a scientific paper about the availability of flavor compounds in diluted vs undiluted whiskey.",
"http://blog.khymos.org/2007/06/03/new-perspectives-on-whisky-and-water/"
] |
[
"When listening to music, individual areas of the brain are \"activated\" for melody, rhythm and pitch. Are these areas in the exact same place in my brain and yours?"
] | [
false
] | Just a question which came to mind when watching a documentary on the abilities of the human brain. (only lasts 30 seconds or so) illustrates the idea. Are these, and other distinct areas of the brain used for other activities, always in the same "position" within the brain and are they activated by the same stimuli? C... | [
"Okay, so first, caveat, I'm a bit of an fMRI skeptic. This is not to say I think it's all lies, but it is the number 1 area of neuroscience that science writers tend to run with, and the authors never make any attempt to correct them.",
"Whenever you read anything the that talks about fMRI, you need to remember ... | [
"Ah, the good ole' dead salmon..."
] | [
"I know, such an excellent straw man! ;) Listen, the biggest skeptics of fMRI methods (and claims) are likely to be people within the field. That's how a field evolves, even if those outside the field can't keep up. Anyway, hilarious that the salmon experiment was brought up after saying that fMRI research \"is... |
[
"In layman's language, how does the process of fat loss occur?"
] | [
false
] | null | [
"You lose fat when your body pulls more energy out of your fat stores than it puts into them.",
"That is controlled by the biochemistry of hormones that your body releases. Insulin and glucagon are the big players, but biochemistry is really complex.",
"And the hormone levels are controlled both by what you eat... | [
"The body does not generally turn fat to glucose; it just burns the fat directly."
] | [
"The body does not generally turn fat to glucose; it just burns the fat directly."
] |
[
"Why is pancreatic cancer so deadly? How close are we to a cure?"
] | [
false
] | null | [
"There are a couple of reasons why pancreatic cancer is especially deadly. First - there is no reliable way to screen for it. Prostate cancer can be detected by searching for prostate-specific antigen in the blood, and breast cancer can be detected by imaging. Pancreatic cancer is rarely detected before it has g... | [
"Devising a sensitive protein test is a helpful step, but finding an accurate biomarker is a whole different problem. As an aside, I love how much the media loves to focus on the idea of the \"brilliant teenager\" while ignoring ",
"other researchers",
" who did the same thing, or ",
"ther techniques",
" t... | [
"Devising a sensitive protein test is a helpful step, but finding an accurate biomarker is a whole different problem. As an aside, I love how much the media loves to focus on the idea of the \"brilliant teenager\" while ignoring ",
"other researchers",
" who did the same thing, or ",
"ther techniques",
" t... |
[
"Does taking a shower after sunbathing affect vitamin D absorption?"
] | [
false
] | This is something I've heard but can only find 'alternative' "health" '''sites''' that advocate this idea. | [
"Vitamin D is synthesized by a photochemical reaction occurring within your cells. Your body produces a precursor, the UV light excites that precursor molecule and changes its shape into Vitamin D. It's all internal and you're not actually getting vitamins from light you're just utilizing UV energy to convert molec... | [
"Can you explain? As far as I know, Vitamin D synthesis occurs in the strata basale and spinosum a few layers into the epidermis."
] | [
"Can you explain? As far as I know, Vitamin D synthesis occurs in the strata basale and spinosum a few layers into the epidermis."
] |
[
"How much do vitamins actually help? My family is very pro vitamin and I feel like they're wasting hundreds a year."
] | [
false
] | Someone was asking about it in and it sparked my interest to find some evidence to back all of this up. Thanks | [
"Your knowledge of nutrition/supplementation is ",
" outdated. ",
"Fortified foods are often not fortified with enough nutrients to prevent secondary deficiencies of quite a few things. Many nutritional deficiencies are quiet common in the general population. You've also missed the ball on a number of them, her... | [
"[some stuff ",
" per \"no medical advice\" rule]",
"You'll often hear reports of how \"a study found xyz to be beneficial to your health, because xyz deficiency may increase your risk of Redditosis\", but this rarely translates to \"you, random person on the street, with no signs of xyz deficiency or Redditosi... | [
"The question is, as I interpret it, \"is it worthwhile for my family members to take vitamins?\" (Which I take as the equivalent of the question \"",
"?\") Without more medical history, we must assume that the OP's family members are random members of the general population, and so ",
"I say no",
", because ... |
[
"I have fiery red hair. Occasionally though, I'll find a pitch black hair on my body. How can my body produce black hairs even though it can't produce Melanin?"
] | [
false
] | null | [
"Red hair is caused by a recessive trait, it means you need two copies of the gene to show red hair. The gene is responsible for the conversion of pheomelanin into eumelanin. The first causes red hair, the second black hair. The gene for black hair is dominant, so you only need one.",
"Research that found out the... | [
"Question. Most people with black hair have significant amounts of red in their hair which shows strongly when bleached. Is the red underneath the black or is the black somehow converted to red?"
] | [
"I have jet black hair and whenever I grow a beard I always get occasional red hairs in my beard and I always wonder why. "
] |
[
"Would it be possible to domesticate 'large cats' (tigers, lions, etc.) like we did with wolfs?"
] | [
false
] | [deleted] | [
"Cats self-domesticated, as in, they moved into human settlements because human settlements attracted the small mammals (rates, mice, etc..) that are their prey. Humans kept them around, except for a few cases of foolishness (Black Death Europe, I'm looking in your direction) because the cats didn't compete for res... | [
"Dogs ARE domesticated wolves. I think the OP was referring to dogs."
] | [
"Sure thing. It might take a while, but it would be possible to do so.",
"Check out the ",
"Silver Fox experiments",
" for something similar to what you are talking about, except with foxes."
] |
[
"If someone acquired all the discarded but legal currency currently in landfills in the U.S. , approximately how much money would they have?"
] | [
false
] | null | [
"Economics"
] | [
"Economics"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/estimation",
"/r/theydidthemath",
"guidelines",
"/r/askscience",
"If you disagree with this decision, please send a ",
"message to the moderators."
] |
[
"Are there any lifeforms that don't rely on sunlight (even indirectly)?"
] | [
false
] | Can any lifeforms survive without sunlight? Objectively speaking, chemoautotrophs don't create energy from sunlight, so they don't rely on the sun. But according to several sources, this is misleading. I saw that the chemoautotrophs in Lechuguilla, for example, use atmospheric oxygen (derived from sunlight-driven photo... | [
"The chemoautotrophic bactieria you mention \"use sulfur compounds, particularly hydrogen sulfide, a chemical highly toxic to most known organisms, to produce organic material through the process of chemosynthesis.\" ",
"https://en.wikipedia.org/wiki/Hydrothermal_vent"
] | [
"There are whole ecosystems on hydrothermal vents in the deep sea (aka \"black smoker\") which are completely indepedent from sunlight. At the beginning of their food chain are chemosynthetic bacteria living from sulfur compounds and minerals dissolved in the geothermically heated water of the vents."
] | [
"Desulforudis audaxviator",
" seems to be completely independent of what is going on at the surface. It needs groundwater to exist, but it lives deep enough so its environment should stay warm even without sunlight."
] |
[
"Obese people seem to exert a lot more effort doing everyday activities like walking. Do they burn more calories doing these activities than a fit person?"
] | [
false
] | When they first start exercising, do they burn calories at a faster rate than a fit person? | [
"The rates are the same, but because there's more biomass, they require more energy to do every activity, including just sitting. An obese person must distribute more nutrients to a greater area while using similar heart/lung volumes to their slimmer counterparts. The vascular organs compensate for the additional m... | [
"It takes more energy to move an object with mass 2x than an object with mass x if distance moved and time taken are the same. Calories are a measure of energy, so as long as they perform the same motions, they are burning more. "
] | [
"What is your defintion of fit? Fit as in a olympic athlete, or fit as in not obese. Obese people absolutely burn more calories when doing activities then your average person simply because they have to tote around the extra weight. I seriously doubt they burn more calories then someone in there athletic prime. ... |
[
"Why is the relationship between electricity and magnetism perpendicular?"
] | [
false
] | I understand that the math works on paper and experimentally we see that the relationship between magnetic fields and electric charges/currents behaves as is does, but is it so? Why is the force on a charge in motion perpendicular to its velocity and the magnetic field? | [
"as it's inherently a quantummechanical phenomenon",
"This is simply not true. Electric currents create magnetic fields; this has nothing to do with quantum mechanics. And the form of the forces laws, etc., that OP refers to are perfectly classical (non-quantum) results.",
"What you may have heard is that to ... | [
"There are many ways to approach this, but it is important to separate out physical effects from conventions, and to recognize different ways perpendicularity arises.",
"At root, the connection between electricity and magnetism is dictated by special relativity. Electric fields plus special relativity imply the ... | [
"If I understood it correctly, a magnetic field is really just an electric field experienced from a different frame of reference. Is that not so?",
"Sort of but not really. For example, think of the force between two current-carrying wires. The magnetic field causes a force between the wires.",
"I can't pick a ... |
[
"How populated with life is an ocean?"
] | [
false
] | I'm not sure if this is the right place to ask this, or even if there is an answer to this question, but after thinking about what it would be like to be stranded in the middle of the ocean I was wondering what the chances would actually be that you would run into life? Is the ocean as populated as a jungle or a desert... | [
"I'm just speculating here, but it probably has to do with the availability of water. In the ocean microorganisms can get all the water they need by simple diffusion.",
"Water also helps to move both the organism and any resources/food it needs around. Simpler organisms do well when the advantage of locomotion is... | [
"Follow up question here, why is it that the majority of oceanic autotrophs are microscopic, in contrast to on land where multicellular plants are dominant?"
] | [
"Follow up question here, why is it that the majority of oceanic autotrophs are microscopic, in contrast to on land where multicellular plants are dominant?"
] |
[
"What does it mean for a spatial dimension to be small?"
] | [
false
] | [deleted] | [
"Dimension refers to the number of coordinates you need to specify in order to say where an object is. Suppose you have a particle that exists on the surface of a cylinder of infinite length. How many coordinates do you need to say where this object is on the cylinder? The answer is 2. A very natural choice of coor... | [
"Consider the analogy of a human and an ant on a tightrope. The human experiences only one-dimension, forward and backward. The ant experiences two dimensions, forward, backward and around the rope.",
"In a more empirical sense, experimental physicists will look for other dimensions by measuring forces at small s... | [
"So, to take your analogy further, unfurling dimensions would be like if the rop suddenly unfolded into a bridge, something that now has a forward/backward and a left/right dimension?",
"Or would it be more like an enormous cylinder, large enough for you to walk around the way the ant did?"
] |
[
"Comparison of neural firing in recall vs. actual sensory intake"
] | [
false
] | I hope this is the right place to ask because this is a topic that's been bugging me for quite some time. Is there some sort of neural mimicry when recalling a sensory event and it nearly feels like you can "smell the kitchen aromas of your childhood home" or "hear the lapping waves on your honeymoon," for example? Bey... | [
"What I can tell you is that nobody really knows exactly how memories work. But the patterns in the brain would be similiar when recalling it, yes."
] | [
"fMRI's, etc are a start, no? I'm sure they've been done"
] | [
"Are you interested in fMRI studies? In that case, a google scholar search ought to turn up some results that show the similarities between recall of a memory and sensory input.",
"I'll try and summarize what I know of it simply, ",
"Mostly what you will find is that the activity is ",
" but weaker during rec... |
[
"How can scientists tell that there is very little antimatter in the universe?"
] | [
false
] | Based on the Wikipedia level reading I’ve done it appears that in all respects antimatter should behave exactly as “regular” matter. So then how can we be sure that there aren’t galaxies, stars, etc made of antimatter? What led scientists to the conclusion that all of the universe is made out of regular matter? I’m not... | [
"Antimatter interacting with matter should be so dramatic that it would be easily observable. We don't see this, so it looks like the observable universe is all regular matter.",
"Galaxies collide and merge with each other all the time. Although the individual stars rarely collide, galaxies are full of loose gas,... | [
"That is really interesting, thanks! Is there any further reading you'd suggest? :)"
] | [
"Note that this in its doesn't rule out extremely large scale variations, larger than the scale of the observable universe - i.e. what if we are a \"pocket\" of regular matter and we are surrounded by antimatter that's over the \"horizon\"? ",
"And even that doesn't solve the problem, you'd still have to answer h... |
[
"What are the chances of getting this 39?"
] | [
false
] | [deleted] | [
" ",
" ",
" ",
" I tried creating a program in c++ (",
"sourcecode",
" if you want to run it) to calculate in how many ways you can get a number between 1 and 100, using 5 operations (+, -, *, / and ^) and applying them in all the possible way to all the possible permutation of 13 cards extracted 4 times ... | [
"If you draw four cards, without replacement, out of a standard 52-card deck, the chances of getting three 10s and one 9 is (4/52)x(3/51)x(2/50)x(4/49) x 4, which comes out to around 0.000049",
"(I'm assuming that face cards are worth 11-13, not 10)",
"Basically, since it doesn't matter what order you draw them... | [
"If you were counting face cards as 10 (no jokers) than the odds improve considerably to:",
"(12/52)x(11/51)x(10/50)x(4/49) x 4 = 0.000812 or about 1/308 and 66 times as likely as counting face cards as 11-13."
] |
[
"why are natural modulation transfer functions usually low-pass?"
] | [
false
] | blur, or muffling, etc., seems to be a ubiquitous physical process. high frequency information is lost when an image is focused, when a sound is transmitted through a medium, when a signal is transmitted - background noise usually swamps high frequencies first. is there a general sort of physical theory of why this is ... | [
"The most fundamental reason for this is inertia. Let's take an example from acoustics. The walls of an acoustic chamber will be largely stationary - that is, they will have high amplitude of motion at zero frequency component. Let's consider now, that everything creeps, slowly. The walls slowly settle under g... | [
"okay, i like this answer. bigger things take more energy to move around, so if there's energy washing around all over the place - impulses, broadband - smaller things will get knocked around more than bigger things.",
"and, 'inertia' clearly gets used in more conceptual or metaphorical contexts to explain more c... | [
"Acknowledging that e.g. the undamped harmonic oscillator does exhibit a high frequency roll-off, I disagree that inertia alone leads to the ubiquitous appearance of low-pass filters in physical systems because that description alone doesn't include damping. I would argue that the reason is because in most systems,... |
[
"Are phthalates in men's grooming products a legitimate concern?"
] | [
false
] | This could be another media scare or not but I came across this news article from a family member who is concerned from me. Basically it says all the cleaning products (that I happen to use: pert, old spice deodorate, Gillette shaving cream) have phthalates in them which are linked to cancer. Is this something that is ... | [
"I am not an expert in toxicology, but one of my friends has done research into phthalate risks for humans, so I've picked up a little. Keep in mind that \"phthalate\" typically refers to a family of products, not just one specific chemical. Here are some of the key points from a good 2005 meta-analysis of publishe... | [
"In short, not really.",
"Pthalates are now uncommon in personal care products excluding nail polishes. They are rarely added to anything else as they have mostly been phased out of personal care products. If they are present, they are in the fragrance–so they're in such small quantities as to be nearly harmless.... | [
"In Europe some phthalates are forbidden. Here a link to the actual legislation. ",
"http://europa.eu/legislation_summaries/internal_market/single_market_for_goods/technical_harmonisation/l32033_en.htm"
] |
[
"How do airplanes maintain cabin pressure?"
] | [
false
] | Is it something similar to the way humans equalize? Is it an entirely different mechanic? | [
"Lets first talk about engines.",
"Aircraft turbines work by compressing air, injecting fuel in it, setting it on fire and then using the expanding hot air to drive the compressor and propel the aircraft forward. ",
"A small part of the air that has been compressed but not yet mixed with fuel is used for variou... | [
"they take some of that bleed air",
"This is true for most ",
"(but not all)",
" jetliners. ",
"Pressurized piston engined aircraft usually use turbocharger bleed air. "
] | [
"Compressed air is taken from the engines' compressor stages (low pressure stage during cruise, high pressure stages during descent and other low power operations). And there's a release aperture that prevents the cabin from being overpressurized. "
] |
[
"Can someone explain shale gas (fracking) using scientific evidence as objectively as possible?"
] | [
false
] | [deleted] | [
"This short video",
" explains fracking better than anything else I've seen on the topic. It was posted about a month ago to ",
"/r/videos",
" and you can view the thread ",
"here",
". "
] | [
"Fracking is essentially a technique to recover gas out of impermeable rock (shale). Drillers drill down to the shale layer and then turn the drill bit horizontally into the shale layer. Next, they fracture the shale layer with gun charges or hydraulic pressure to make the shale layer more permeable and release t... | [
"Here's where it gets messy--the water is pumped out so the gas can be captured at the wellhead, but the water, chemicals, dissolved hydrocarbons and other matter leached from the earth have to go somewhere.",
"It's worth noting that this is not a new problem- and that the fluids that come out with natural gas ar... |
[
"How did other human species go extinct? How did modern homo sapiens sapiens 'descend' from other humans?"
] | [
false
] | So there existed a handful (ten?) of varies species within the genus throughout history. All but the modern have died off. How did this happen? Were these other species fairly small in number and not geographically spread out? Were these multiple species ever living together and in proximity to each other? Which othe... | [
"Look at the wikipedia article on the timeline of human evolution. It has most of your questions answered. ",
"en.m.wikipedia.org/wiki/Timeline_of_human_evolution"
] | [
"You can't really say with certainty. The traditional concept of human evolution as species A-> B-> C-> D-> Homo sapien is fundamentally flawed, t-shirts and bumper stickers notwithstanding. Of the pre-human species of Homo we are aware of, some or none may be our direct ancestor, the species we speciated from. We ... | [
"Not really. The genus Homo is bushy, not linear, and it's tough to pick out how everything is related. It's really likely that we haven't even uncovered all the members yet. "
] |
[
"What is an itch and how do you get one?"
] | [
false
] | null | [
"Itches can arise for a variety of reasons. The standard model for explaining itchiness is that your body has nerve fibers that specifically report itchiness, and they can be triggered physically (something physically present on your body) or chemically (something injected into you).",
"However, this explanation ... | [
"Interesting. When I searched, I got this s's my first result. "
] | [
"Itches are a histamine reaction"
] |
[
"I need to recreate fetal heart sounds (the acoustic s1 and s2 signals) in Matlab. Having a really hard time finding literature containing a mathematical model. Can anyone help me?"
] | [
false
] | Maybe I'm not Scholar enough to use Google? | [
"from what do you have to create them? Their mechanics? The underlying electrophysiology? Does it have to vary based on a simiulated input? I don't follow."
] | [
"There's a project I'm working on where the ultimate goal is to gather the acoustical sound of a fetus's heart beat from the surface of a mother's abdomen (and process/filter the acoustic signal etc etc). For testing purposes, I would like to be able to \"recreate\" the acoustic sound of a fetal heart beat through ... | [
"So what else do you need exactly?"
] |
[
"In regards to the cooling of Nuclear Fuel Rods, why not use Liquid Nitrogen?"
] | [
false
] | [deleted] | [
"There are several reasons.",
"1) Liquid Nitrogen has a very low heat capacity compared to water - meaning that although it is very cold, it will heat up much more quickly than an equivalent amount of water for each unit of heat added to it",
"2) Introducing LN2 to the pool of warm water will cause the nitrogen... | [
"The issue isn't the actual temperature. The issue is removing energy from the rods. While liquid nitrogen may be cold, water can hold more thermal energy due to its high specific heat. More info in this thread.",
"http://www.reddit.com/r/askscience/comments/g5wb3/did_the_cold_weather_help_at_all_in_the_japan/... | [
"this. Also, keep in mind that cooling down a reactor is not a matter of doing it quickly, but doing it relentlessly. The fuel rods will keep emitting tremendous amount of heat even after being temporarily cooled down. And because you want to ricirculate the coolant as much as possible to avoid having to expel it i... |
[
"Are there any examples of a animal evolving in a specific way that is directly caused by humans?"
] | [
false
] | Whether the change was a result of human behavior or our species mass spreading across the planet has always interested me | [
"There are really a ton of examples of this. Humans have been a singular force in nature since they came about. Basically everywhere we go things have to adapt or be driven to extinction. And to the extent that extinction drives evolution we've been responsible for a lot of what you see around people. ",
"Just ... | [
"Many; ",
"this is a well-known example",
"."
] | [
"Would any kind of selective breeding count? We have done this with cows/bulls, horses, dogs, etc."
] |
[
"Why doesn't cancer instantly spread to the entire body like other diseases?"
] | [
false
] | I know that cancer can spread to other parts of the body but why does it take so long and why does it sometimes not happen at all? Wouldn't just a few cells moving through the body be enough to "infect" another part of the body? | [
"‘Cancer’ is a term that encompasses many stages of the disease that can come from any number of different kinds of cells and in countless different ways. People who have researched their entire lives still have much to learn about it. But I’ll try to sum it up with the limited knowledge I have. ",
"Most cells ha... | [
"Cancer biologist here. The process of cancer cell \"spreading\" broadly consists of local invasion and metastasis. These are both multi-step processes and there are many barriers the cancer cells encounter along the way. ",
"In the local invasion step, the cells must \"digest\" through a structure called the bas... | [
"Your premise is incorrect. Many pathogens don’t “spread to the entire body” in the normal progression of the disease. For example the influenza virus infects the respiratory system, while cholera infects the digestive system.",
"Infection of the blood is quite serious and often results in sepsis, which kills abo... |
[
"Could someone please tell me the short-term and long-term health affects of alcoholism?"
] | [
false
] | I guess I'm asking for the not-so-obvious effects (as you could read on the internet). What about premature aging? Wrinkles? What about the irreversible, with regards to the physical and mental and psychological? | [
"I can give you part of an answer for the liver failure, which is one of the most dreaded outcomes of long term alcohol abuse. Borrowing from several comments I made quite a while ago:",
"Hepatic steatosis (fatty liver) occurs in roughly 90% of heavy drinkers. This can show up in as little as two weeks following... | [
"I can give you part of an answer for the liver failure, which is one of the most dreaded outcomes of long term alcohol abuse. Borrowing from several comments I made quite a while ago:",
"Hepatic steatosis (fatty liver) occurs in roughly 90% of heavy drinkers. This can show up in as little as two weeks following... | [
"I can give you part of an answer for the liver failure, which is one of the most dreaded outcomes of long term alcohol abuse. Borrowing from several comments I made quite a while ago:",
"Hepatic steatosis (fatty liver) occurs in roughly 90% of heavy drinkers. This can show up in as little as two weeks following... |
[
"Are giggling and smiling hardwired to be related to happiness, or could you teach a baby that laughter is for when you are sad?"
] | [
false
] | null | [
"OK, I've written a lot of replies to those that have said yes, but let me add one broad comment about why the answer to your question is almost certainly 'NO'. As people have pointed out we can't be certain because such an experiment would be unethical and so the obvious experiment to settle the issue can't really... | [
"Laughter",
" is an involuntary response to several types of stimuli, including happiness. It is, however, mediated by cultural and environmental influences. As in your example, a person could be conditioned to laugh involuntarily when some stimulus makes them sad.",
" ",
"SurfKTizzle",
"'s ",
"excellent,... | [
"Laughter is an effective strategy for minimizing the threat of otherwise threatening situations, but methinks that ironic effects of control will play into the answer (I have no idea what the current state-of-the-field opinion on this stuff is, but Daniel Wegner has a ",
"line of research on it",
")."
] |
[
"Is saying \"shh\" an universal human behaviour for commanding silence, or does it vary from culture to culture?"
] | [
false
] | Maybe wrong subreddit but still. | [
" seems to be derived from the Middle English word ",
", meaning silence",
"However there is definitely a correlation of the letter 's' being used for interrupted speech. Wikipedia has a list of \n",
"Cross-linguistic onomatopoeias",
" where you can see the similarities.",
"So it seems like using the ",
... | [
"So it seems like using the sss sound is universal for humans due to its soothing nature - typically silence is synonymous with peace.",
"I've heard that babies are calmed by shushing because they associate it with the sorts of sounds - mother's pulsing blood, etc - they would have heard during their time in the ... | [
"Not sure that makes my sense, as we generally find shushing calming rather than alerting."
] |
[
"What's actually happening when you \"inject current\" into a neuron?"
] | [
false
] | So I'm ashamed to admit this, as a student who is about to graduate with a BS in Neuroscience and attending a PhD program in the fall. I understand the Nernst potential and a fair amount of cable theory and Hodgkin-Huxley stuff, but I haven't the slightest clue how a simple electrode works on a molecular level. When so... | [
"Is the electrode literally inserting protons or electrons into the cell? I highly doubt this...",
"Correct (I mean \"I highly doubt this\" is correct, not the first part). At least in every intracellular recording I've ever done, what is actually sticking in the cell is a glass micropipette filled with some kind... | [
"1) In terms of physics, I suppose the force is just plain old repulsion of like charge - whatever it is that pushes the charge around any electric circuit. In terms of the system, there's some sort of standard electronics gismology involving op amps I'd have to go look up.",
"2) This is not something I have ever... | [
"The substance the current is made out of is ",
" the positive and negative ions in the pipette solution. And you're not really changing the Nernst potential - the current flows out of the pipette tip and into the cell, then out of the cell across the cell membrane, and then continues on to the reference electrod... |
[
"Could the substance known as \"atomic trampoline\" be used as a shield for space craft or even body armour?"
] | [
false
] | I'm talking about the substance made of several different elements in this | [
"If anything i would expect it would be even worse (i.e. more easily punctured) than normal metal now. The reason the ball rebounds so high is that the material is absorbing less of the energy from it. To make something bullet proof you want it to absorb and dissipate as much of the energy as possible. If more ener... | [
"The impact on the armor is focused on the area of the bullet ",
" it bounced it back, which means that the armor stayed intact and did not deform or break.",
"Which means that it applied the force to the rest of the craft over an area equal to the armor-craft contact area. Even if the momentum transferred doub... | [
"Yes, of course. But that doesn't change what I wrote. If the projectile leaves the impact with its speed reversed, then you must have reversed it's momentum instead of simply canceling it."
] |
[
"A question about the observer in the double slit experiment - Can the observer just be a person, without the aid of equipment?"
] | [
false
] | As I understand it, when a piece of equipment is used to observe the particle, it colapses the particle's wave function, causing it to act like a particle rather than a wave. (I might be off on some of the details, but that's the general idea, right?) But everything I've read always talks about a piece of equipment bei... | [
"Short answer: Yes, a human seeing something ",
" be an QM observer. So can a rock.",
"I hate the word \"observation\" as used in quantum mechanics. The meaning of the term as it's used in QM is very different from its layman meaning, and the conflation of the two causes a lot of confusion like your question... | [
"Oh, I didn't really address your last paragraph there. I should have, because it's illuminating. In the situation of looking at a wall, no, you're ",
" observing the wall. You're observing the light that's been reflected off the wall. The ",
" is what's observing the wall."
] | [
"Pretty much. Oddly enough, the three least-used senses -- touch, smell, and taste -- are also the senses where what you're \"observing\" in the QM sense is the same as what you'd say you're observing in the normal sense. The senses we consider more informative are ones that don't directly interact with the objec... |
[
"Where do all the bubbles in water come from during boiling?"
] | [
false
] | This is quite possibly the stupidest question I've ever asked. =/ | [
"Where do all the bubbles in water come from during boiling?",
"When the water has reached a vigorous rolling boil, the bubbles coming up to the surface are made of water vapor. Water is undergoing a phase transition from liquid to gas at the bottom of your hot pot and forming little gaseous bubbles of water vapo... | [
"Also, I remember hearing once that the bubbles that you begin to see on the side of the pot before the water reaches a full blown boil are not primarily water vapor, but are actually dissolved gasses that are separating out of the water.",
"Yes. This is true because for most gases, solubility in water ",
" wi... | [
"This is so wrong. The bubbles is water vapour. They form due to the vapour pressure at that temperature being greater than the pressure above it. Heating is not uniform so some molecules are hotter than the average. (Average kinetic energy of the water is its temperature). ",
"Water doesn't split into hydrogen a... |
[
"What causes the air to smell when a rain storm is moving in?"
] | [
false
] | null | [
"Bacteria living in the soil and on surfaces such as pavement and vegetation react with the water and produce that distinct odor. The scent is more pronounced when there is a longer duration between rain events and is scientifically referred to as 'petrichor'. You may smell it before a rainstorm because winds trans... | [
"More specifically when raindrops impact dry, porous surfaces, tiny bubbles are produced which launch droplets containing bacteria and organic matter into the air. These droplets and the aerosols they form are what's lofted by the wind and carries the smell with it. A paper came out of MIT a few years ago about thi... | [
"Where do I buy a candle with this smell?"
] |
[
"How did birds develop wings?"
] | [
false
] | [deleted] | [
"A good example of this is the flying squirrel. The flying squirrel clearly has an advantage of other squirrels in that it can escape threats. It clearly cant fly, just glide.",
"Over time, the squirrels that could glide further gained a competitive edge and could reproduce. Perhaps one day (or maybe they have al... | [
"The evolution of flight (in dinosaurs), the evolution of feathers, and the evolution of birds are very much decoupled from each other; flight seems to have occurred in non-avian dinosaurs as well. Evolution proceeded as you would expect -- there's no issue of irreducible complexity in dinosaur wings. Basically, al... | [
"That's what ",
" seems to have been, but it's not clear how much gliding or flying it did. It had wings but still had claws on the ends of them."
] |
[
"Is it actually impossible for matter to occupy the same space, or is it just difficult due to repulsive effects of electromagnetism or some other force?"
] | [
false
] | null | [
"The short answer is that this effective repulsion comes from the fact that for a certain type of matter multiple particles cannot occupy the same ",
" This idea, called the ",
"Pauli exclusion principle",
", is ultimately the explanation for why solids are so hard to compress. This concept explains things as... | [
"You've described the behavior of fermions, but is there some ",
" for why they have this behavior? Or is it simply that we observe them with this behavior, and so our models must account for them? I mean I know the latter is true; I guess what I'm asking is this: is there an explanation for this behavior beyond ... | [
"Back in the early days of quantum mechanics this behavior ",
" just a postulate that was introduced in a somewhat ad-hoc fashion to make sense of experimental results. The explanation came with the development of field theory and is called the ",
"spin-statistics theorem",
"."
] |
[
"When picking black mulberries, I get red stains on my hands. By the time I get home, they can’t be rinsed off with water and soap. However, about 10 hours later they just disappear, without any action on my side. Where do they go?"
] | [
false
] | null | [
"But 10 hours seems like a really short period of time for this to occur. This would mean that it doesn't penetrate deeper than the very outermost layer of skin. I'm not saying you are wrong, just that this would be an implication."
] | [
"A possible way to test this would be to rub your hands together once dry. If done rough enough this will lift off the top layer of skin and, if I'm correct, remove any discolouring."
] | [
"This needs more experiments. "
] |
[
"If there are two substances (chemicals) can it react in a way that only one of the substances changes at all?"
] | [
false
] | I'm curious if this is possible, and if so, perhaps an irl example. This being that you have Substance 1 (S1) and substance 2 (S2). When S1 and S2 meet at a neutral temperature, only S2 has a measured and completely same reaction, regardless of the mass of S1. EXAMPLE-ISH: I'm going to replace chemicals with a simple, ... | [
"What you're referring to is ",
"catalysis",
", and it happens quite frequently.",
"For example, in the ",
"Elephant's Toothpaste reaction",
", potassium iodide and hydrogen peroxide interact. The iodide catalyzes the decomposition of the peroxide to water and oxygen gas. The reaction would still happen w... | [
"more enzymatic than catalytic. even catalysts undergo some sort of energy change that allow a reaction to occur. enzymes are acted upon by molecules and do not require a change in energy state but a conformational change based on the change of certain substances around them."
] | [
"I appreciate your in depth example. I love this /r/"
] |
[
"Why are men in western countries half as fertile today as they were in the 1970's? What is the biggest contributor to this recent Male Fertility Crisis?"
] | [
true
] | null | [
"The meta study didn't control for BMI/obesity.",
"Being overweight and especially being obese are linked with lower sperm count.",
"People have gotten far more overweight/obese.",
"It is likely the primary culprit.",
"Unfortunately the importance of BMI/being overweight was not well understood back in the ... | [
"Physical activity is also likely a huge factor. Working life has become increasingly sedentary - now moreso than ever. Testosterone levels correlate with physical activity over both long and short term periods, and Testosterone levels correlate with fertility - so it's not a long stretch to imagine that's a factor... | [
"Obesity is the most obvious culprit.",
"Being overweight lowers sperm count a bit, being obese lowers it a lot.",
"Sitting/sedentary lifestyle seems a very likely culprit as well, and may contribute to the above."
] |
[
"Is there an \"upper limit\" to the size a neuron can get?"
] | [
false
] | I vaguely remember learning that some seminal early neurophysiology was done in squids because they had particularly large axons. but what happens when you take this to an extreme. For example, the cells that innervate the most posterior muscles and skin of a blue whale have to traverse a distance of upwards of 25 mete... | [
"There is a practical limit to the size of cells as we know them as dimensional analysis shows surface area to be a function of length squared and volume to be a function of length cubed. Since there is a limit to the rate that nutrients/waste can pass the cell membrane there will be a certain maximum size to a ce... | [
"thanks! a few follow up questions:"
] | [
"do you know how big the longest/largest observed cell is?",
"The ostrich ovum is considered the largest animal cell in popular culture. While it may be so by weight or volume you are correct that the axon of neurons (especially for large mammals) is a solid contender. The equivalent of the sciatic nerve for th... |
[
"Why does a bike become more stable as it increases in speed?"
] | [
false
] | null | [
"A lot of wrong answers here. ",
"Both the caster effect and gyroscopic effect have been disproven as the ",
"* source of bike stability.",
"http://www.wired.com/gadgetlab/2011/04/riderless-bicycle-cornell/",
"If you watch the attached video, you can see instances where they use wheels so small that the gyr... | [
"You obviously don't understand this experiment.",
"Is in poor taste and could have been left out. Your point would be no less valid."
] | [
"... how is it possible that there is still uncertainty in such an accessible and human-scale object? we built the LHC for gods sake. "
] |
[
"Imagine a planet where organic life has evolved independently from Earth. How likely is it to be edible for humans? If not, would it be toxic or indigestible?"
] | [
false
] | null | [
"I would say very unlikely that it would be edible for humans. On Earth, we adapted to eat what is around us. When we eat something, our body knows how to take it apart and release the energy, minerals and vitamins. The probability that we adapted to consume something on an alien planet is very unlikely. ",
"T... | [
"Are the creatures that live in the Mariana Trench edible?"
] | [
"why isn't it used comercially as a way to make diet products?"
] |
[
"What is the anti-derivative of position?"
] | [
false
] | Since velocity and acceleration are the 1st and 2nd derivative of position respectively and since position is in units of distance, velocity is in units of distance per time, and acceleration is in units of distance per time , then would the anti-derivative of position have any meaningful quality or would it be a purel... | [
"The term ",
" has been coined for this concept, a measure of how much time you spend how far away from a given position.",
"This comment",
" from an earlier ",
"/r/askscience",
" thread should also be helpful."
] | [
"Sure there is! Just like there is velocity, accelleration, jerk, jounce, snap, crackle, and pop (yes, those are real terms)! It's just that such a measurement is unlikely to be useful."
] | [
"It's called absement, and has a few speciality applications. Apparently it's important in a water jet musical instrument: ",
"http://www.eyetap.org/papers/docs/acmmm2006presement_as_published.pdf",
" "
] |
[
"Is it possible to ascertain exactly how fast we're moving through space?"
] | [
false
] | Since the universe is expanding, and we're moving around the center of the galaxy, and around the sun, and spinning on earths axis, and rotating, can we ascertain exactly how fast we're moving? Alternatively, is it possible to know what it means to not be moving in the universe? | [
"Yes, but it will always be with the caveat, \"...Relative to...\" and by the same token, \"Stationary ",
"\"",
"For the rest, all the way back to the last scattering surface: \n",
"https://astrosociety.org/edu/publications/tnl/71/howfast.html"
] | [
"You've pretty much answered your own question. We are moving at one speed around the center of the galaxy, another speed around the sun, another speed around the center of the Earth. All motion is measured relative to a reference point."
] | [
"If universe is finite, then we must be moving at certain speed with reference to that centre. Since currently the topography of universe is not known for certain we cannot really answer your question at this juncture, but I'm sure there must be an absolute speed with centre of universe as reference frame. My 3c."
... |
[
"Can cats get dizzy?"
] | [
false
] | I was spinning in a chair with a kitten and he didn't appear to be phased at all. He didn't even want to leave the chair but was put down and then walked away with no noticeable vertigo. So, can cats get dizzy? If not, what happens when cats go in cars and start to drool when they look out the window? Thanks for being ... | [
"A cats balance is like a humans ",
"source",
" so I would imagine that it would be subject to the same failings. So yes, I would postulate that cats can get dizzy."
] | [
"Cats' inner ear anatomy is very similar to ours, so they certainly can get dizzy. However, they have two advantages over humans: 1. they walk on four legs which gives them better stability. 2. they use their tail for balancing.",
"\nThe combination of these may make them less susceptible to dizziness or, if they... | [
"Dizzyness is caused by the fluid spinning in your ear and how your brain interprets this, right ? I don't see how using four legs and having a tail to balance compensates for this ? "
] |
[
"What Chromosome Disorder would cause me to be sterile?"
] | [
false
] | null | [
"If you are a male (XXY) it's called ",
"Klinefelter syndrome",
".",
"If you are a female (XXX) it's called ",
"Triple X syndrome",
".",
"If it's Klinefelter then you're probably sterile but if it's triple X then you're probably fertile. Both can be diagnosed through a blood test to check your ",
"Kar... | [
"http://en.wikipedia.org/wiki/Klinefelter_syndrome",
"\nAnd here's the source, also suggest retagging as Biology not Chemistry."
] | [
"Kleinfelters?"
] |
[
"Why is electromagnetic radiation emitted at the speed of light?"
] | [
false
] | I don't mean to ask why c=3x10 m/s, nor why things cannot accelerate past the speed light barrier, but rather why the initial velocities of emitted particles = c. Why aren't particles/waves emitted at varying speeds dependant on conditions? Ignoring the fact that waves/particles can be slowed depending on the medium wh... | [
"Because a changing electric field creates a (possibly changing) magnetic field and a changing magnetic field creates a (possibly changing) electric field which keeps going as a light wave.\nIn order for this balance to work it must be moving at the speed of light to all observers (regardless how fast the observer ... | [
"EM radiation is characterized by the behavior of a photon, which is a massless particle. Thus, it takes 0 energy for the photon to propogate at the speed of light. This is not to be mistaken with having 0 energy, instead the photon's energy is directly associated with its frequency. ",
"Contrast this with wit... | [
"Well, as speed of massive object approaches c, energy required to increase speed approaches infinity. IIRC, It's not incorrect, it's just (supposedly) impossible."
] |
[
"I once read about and saw photos of a rare human pigment disorder. All my google attempts at finding this tiger-stripe producing melanin inhibitor fail. I think I'm going about this search wrong. Help?"
] | [
false
] | [deleted] | [
"I believe all humans have these \"stripes\", they are just not visible. I looked this up once when my daughter and son in law (one brown, one white) were joking that their child would come out spotted or striped. ",
"http://en.wikipedia.org/wiki/Blaschko's_lines"
] | [
"Blaschko! I think this is it. I would still love some more information from you guys. Thanks!"
] | [
"I remember seeing a black lady some years ago..She looked as if she had white hands but the white extended up past her wrists like flames..It was beautiful. I've always wondered what this was."
] |
[
"How can someone become algeric to something they were not previously allergic to?"
] | [
false
] | null | [
"One of the biggest points of the immune system is the ability to adapt to new threats. This is the whole reason vaccines work, that we can fight off diseases we haven't seen, and that there are a bunch of childhood diseases you never get again. The immune system is constantly monitoring the body for unfamiliar thi... | [
"No, every mucous membrane in your body has immunocompetent cells, that attack \"pathogens\". In case of allergen getting stuck in sinus, those cells release whole storm of chemical soup (simplifying here, don't want to bore you to death) that: attract other immune system cells, promote inflammation, secretion (th... | [
"What about nasal/sinus allergies? Do the allergens pass into the blood stream?"
] |
[
"Why can't I concentrate indefinitely?"
] | [
false
] | I was hesitant to post this because there have been several questions about cognition and how many calories it burns. But I know it isn't a matter of calories. Hard studying doesn't make me any more hungry than, say, spacing out in front of the TV. So, what is it? What "resource" is being used up that makes me lose foc... | [
"An add-on to this question - what causes \"the zone\"? Maybe not quite the correct scientific term but while sometimes I can't work for 20 mins without losing concentration, fidgeting, checking Reddit, etc. Other times I can work for hours and hours on end with seemingly amazing focus. I'd love to know why, then m... | [
"http://en.wikipedia.org/wiki/Flow_%28psychology%29"
] | [
"I don't remember the precise term for the phenomenon, but I did learn the reason for this.",
"Long term potentiation is the name of the phenomenon by which neurons alter their genetic expression to form physical connections with other neurons. This is presumed to be the basis for memory and learning.",
"This i... |
[
"Will things cool faster in air than in the vacuum of space?"
] | [
false
] | Will things cool faster in air than in the vacuum of space? I ask because things cool faster in water than in air. It seems then that if there is more dense matter around you would cool faster. | [
"It certainly depends on the temperature difference between the air and whatever is cooling. However, with any significant gradient in temperature, the conductive heat loss facilitated by the presence of air will be greater that the radiative heat loss associated with cooling in vacuum. It takes far longer to coo... | [
"To add to this: a thermos, or vacuum flask, is basically a cup surrounded by a small space of vacuum (or a small amount of a poorly-heat-conductive gas). Not only will a vacuum flask keep your coffee hot on the drive to work, large ones are typically used to store liquid nitrogen.",
"So that's a practical appli... | [
"There are 3 basic ways heat transfers. 1) radiation; when an object has a nonzero temperature (no matter what that temperature is), the object radiates energy in the form of electromagnetic radiation; this is how the Sun transfers heat and energy to the Earth 2) convection; through the movement of fluids, such as ... |
[
"Is this one scene from Futurama scientifically feasible?"
] | [
false
] | [deleted] | [
"Just to clarify: you're asking whether an atmosphere that is 80% oxygen ",
" increases the speed at which flames spread?"
] | [
"Even with the entire surface covered by trees, I would expect the ocean to compensate with more oxygen-consuming life. ",
"As the trees grow and spread, there would likely be forest fires, which would consume oxygen and slow the spread -- somewhat like now. It is ",
" likely that it would get to a point that... | [
"Even if it was mostly Oxygen, reactions happen more easily with sufficient oxygen. Oxygen itself isnt combustable"
] |
[
"How do you calculate the probability of a \"lucky run\" on a coin flip?"
] | [
false
] | To elaborate, I'm aware that the odds of every flip is 1:2 for heads or tails, respectively. However, when you do this and record the results, you will often get "lucky runs" of one or the other. Given, it is usually 2-4 at most. But, how do you actually calculate this? How can you calculate the probability of a "l... | [
"Theoretically, each individual coin flip has a 50% chance of heads and a 50% chance of tails, although I think I've read that the side starting face up on a flip has a slightly higher chance and there's the weight of each side to consider. But, let's assume it's a fair flip that's 1/2.",
"In order to calculate t... | [
"If you want the probability starting now of the next set of flips being specifically heads or specifically tails you would do:",
"1/2",
"where x is the number of flips in a row.",
"If you're talking about a lucky run where you don't care if it is heads or tails you would do",
"1/2",
"If you plan on flipp... | [
"Assuming you are only interested in a series without concern for whether it is heads or tails, the probability of getting x-in-a-row would be (.5)",
". Getting 1 head or tail in a row is 1:1, so it would be 1:2 for the next and so on.",
"This assumes you are viewing the probability from a yet to be flipped coi... |
[
"Can nuclear weapons be adapted to have a very small yield?"
] | [
false
] | [deleted] | [
"the Davy Crockett nuclear devices were at the edge of what is possible in terms of yield.",
"The M-388 round used a version of the W54 warhead, a very small sub-kiloton fission device. The Mk-54 weighed about 51 lb (23 kg), with a yield equivalent to somewhere between 10 or 20 tons of TNT (very close to the mini... | [
"I was a tank commander in the US army on Abrams tanks. We go through annual safety training bc we use DU armor and projectiles. The radiation becomes dangerous when it is particulated. Like when a round makes contact or armor is penetrated. Lol, penetrated. We refer to it as DU dust and treat it like the plague. ... | [
"Infantile humor (penetrated, lol) being a more likely reason in this subreddit."
] |
[
"Do two laser beams crossing each other affect each other?"
] | [
false
] | I know the chance of two photons striking each other is minuscule, but can it happen? Is the collision the same as when two pieces of ordinary matter have an elastic/inelastic collision? Also, apart from direct collisions, can the photons in the one beam affect the paths of the photons in the other beam? TL;DR Two lase... | [
"BUT not with each other. Two laser pointers aren't going to do this. Generally you're dealing with a single laser which is sent through a beam splitter a la Michelson Interferometers."
] | [
"You'd get an interference pattern.",
"diagram",
"pic"
] | [
"from relevant discussion in ",
"www.physicsforums.com",
"There are certain interactions termed photon-photon interactions, however they all occur inside media, because they rely on the presence of a nonlinear polarisation. So called 'photon-photon' interactions also require the presence of an atom, so technica... |
[
"What is in store for the future of Cars? How will they be powered etc.?"
] | [
false
] | In 10 years, will we still have gasoline powered automobiles? Or are hydrogen powered cars going to take over? Will they be painfully slow? | [
"To answer your last question first: Future cars will most likely be electrically driven. Electric motors are fantastic machines, with an efficiency over 90% and great power output. As an example, the ",
"tesla roadster",
":",
"The Roadster can [..] accelerate from 0 to 60 mph (0 to 97 km/h) in 3.7 or 3.9 sec... | [
"Try ",
"/r/askengineers",
" "
] | [
"Thanks for a knowledgeable reply! "
] |
[
"How is age of our universe calculated if our solar system was born after the Big Bang? Thanks"
] | [
false
] | [deleted] | [
"The universe is about 4.35*10",
" seconds old.",
"The universe is 3.09 times the half life of uranium 238 old.",
"The universe is 175.4 million times the current human life expectancy in the US old.",
"We usually express long time spans in multiples of a year, which is the ",
" time Earth needs for one o... | [
"Because light travels at a fixed speed, we can observe very distant galaxies and see what the early universe was like. When we use telescopes like Hubble to look for light that has travelled very far, the light has taken longer to reach us than the age of our solar system, and we can see that those distant galaxie... | [
"Other measurements reinforce the observations that have been listed here. By observing ratios of heavy elements (heavy gas and metals) to light gases (hydrogen and helium) and looking at observed fusion rates that produce those heavy elements from the light gases, estimates on age can be developed from initial lig... |
[
"What does \"predisposed to obesity\" actually mean?"
] | [
false
] | Semi-related background to my question: So I saw a really interesting talk last night on epigenetics (shout out to Nerd Nite SF!), and the speaker quoted some very interesting data on caloric restriction and how it possibly slows the aging process (at least it does for sure in mice), and then went on to quote a study ... | [
"First off - the data on caloric restriction -> longevity looks like it might be ",
"a bit overblown",
" Nevertheless, the rest of your questions are still interesting.",
"1) Do the ob mice gain more weight given the same diet? Why?",
"ob/ob mice are obese because they lack leptin, which is partially respon... | [
"Some of my research is into the maternal influence of predisposition towards obesity. There are 3 interacting factors when considering the predisposition to obesity:",
"1) Classical genetic factors - Allele variants, inherited from parents, associated with increased adiposity (such as the famous FTO gene, or MC... | [
"I think you may be trying to untie the phrase \"predisposed to obesity\" from its sociological implications.",
"Though there are certainly sociologic factors at play, there are definitely genetic and environmental factors that play a role as well. ",
"At least some studies that try to control for socioeconomic... |
[
"Latex formulas"
] | [
false
] | Hi! I really enjoy reading this community content but sometimes the equations displaying are too rough to read. As many might know, LaTex is very good at formulas, so I've crafted a bookmarlet that will convert any LaTex like content inside tags in comments to PNG images using service. Just write your formulas as if th... | [
"You're better off adopting the local convention, which involves a ",
"painless JavaScript download",
" similar to your own, but that adheres to the local convention:",
"[",
"; (LateX here) ;",
"]",
"An example of the kind of silliness this allows:",
"[; \\300dpi \\color{red} \\text{ Two guys walked i... | [
"The math reddit is latex compatible if you have the right browser plugin. We could have that here."
] | [
"Thanks, din't knew about it. I would like to see it adopted."
] |
[
"Do I weigh less when the moon is in the sky than when it is not due to its gravitational attraction?"
] | [
false
] | Obviously I realize that my mass would be the same, but if I stepped onto the most precise scale in the universe, shouldn't I weigh less when the moon is up. If not, why? | [
"Since the force of gravity is proportional to the body's mass, and inversely proportional to the SQUARE of the body's distance from the object, the moon's gravity would generate (1/100) / (60",
" times as much force as earth's gravity on you. Thus it is approximately 1/360,000th as strong as earth's gravity. Gi... | [
"you would weigh roughly .33% less",
"Is this due to the Moon?",
"Because 0.33% is ",
" times Earth's gravity and",
"1/360000 is ",
" times Earth's gravity.",
"So, it's ~1000 times less than 0.33%."
] | [
"On Earth's surface, the Earth's gravity attracts you at 9.8 m/s², the Moon attracts you at about ",
"0.00003 m/s²",
". It seems that when the Moon is directly overhead, that number is closer to 0.000031, and when it's directly on the other side of Earth it's 0.000029. ",
"So, you can see that the effect of t... |
[
"Could Sirius and Procyon be orbitally bound?"
] | [
false
] | null | [
"This is the third question you've asked in the last day about Sirius being gravitationally bound to other stars. Is there something you ",
" want to know?"
] | [
"Yes, this here is the logical radix in the inconsistencies I found in astronomy. ",
"Is not the assumption that ",
"d = 1 / P",
" speculative, at best? Does it not assume a euclidian and linear space/time line-of-sight? Sorry about if I use the words wrong. If you understand what I mean, perhaps you could en... | [
"What are d and P?"
] |
[
"Can you get below absolute zero?"
] | [
false
] | null | [
"Yes, but it doesn't mean what you think it means. Negative absolute temperature is actually \"hotter\" than any positive temperature in the sense that energy would flow from the negative temperature system to the positive one.",
"In normal systems at thermal equilibrium, most particles have about the average ene... | [
"It doesn't seem likely getting below zero Kelvin is possible. However the Wired article likely stripped the important fact that they are using a different method of defining temperature from the common one most people are familiar with."
] | [
"Although this is the correct method of defining temperature, and the common one is wrong."
] |
[
"Why do some equations (like universal gravity and Gauss's law) require a proportionality constant, while others (like F=ma and V=IR) do not?"
] | [
false
] | null | [
"It has to do with the units. Gravity, and Gauss's law were both discovered, and describe physical phenomena. They require constants because they are not dimensionaly consistent. F=ma and V=IR are both true by definition. The units of force (and resistance) that we use were specifically designed so that they would ... | [
"This is different. You have to check a derivation of that kinetic energy equation to see why it's there. It's really just a consequence of the definition of work, which should look more intuitive to you"
] | [
"It just has to do with what units you use. You can use units where G=1 or where divergence E = charge density. It happens that the conventional choices don't require a constant of proportionality in Ohm's Law and Newton's 2nd Law, because the conventional units work out without such a constant."
] |
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