title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why does our skin feel warm/hot while sunburnt?"
] | [
false
] | null | [
"A sunburn is usually a first degree burn, and the body's natural reaction is to increase bloodflow to the place that hurts. There's also one (or two) less layers of epidermis on a burn area, so you're feeling more of your own body heat directly."
] | [
"correct, the blood vessels dilate, increasing blood flow near the surface. This is why the skin looks red. "
] | [
"So it's actually physically warmer, not just a psychological thing?"
] |
[
"If we are travelling in a train along the equator at half speed of light, what would a live broadcast of events inside the train look like outside?"
] | [
false
] | Consider a railway track around earth's equator and a train at say ½ speed of light or 2/3 speed of light. Now suppose we are broadcasting events on the train live to the people on ground, so what will the broadcast look like to stationary people on ground. | [
"You would get a crappy signal. As the distance between the station and the train increases, it would take more time for the signals from the train to reach the station (or broadcast tower) which would a varying signal.",
"If the TV crew inside the train were taping a clock, it would run at a slower rate than a c... | [
"Well the most basic principle about General Relativity is that, where ever you are. Regardless of your speed, ",
"\nIf you use a mirror in that Train, the Light would have to bounce from the mirror and reach to your eyes in the speed of light. But from the outsiders perspective if someone would measure the spee... | [
"But from the outsiders perspective if someone would measure the speed of the bounced light.\nThey would think that the speed of light is 1.5 times, why",
"No, they would measure it as light speed exactly. It's the same in all frames of reference, regardless of origin."
] |
[
"How does language develop differently in deaf children who are taught sign language?"
] | [
false
] | Young children often have difficulty speaking concise and coherent sentences, adding in filler words and making frequent tangents. How does this differ in children who are deaf from birth and taught sign language from a young age? Are they able to communicate their thoughts more clearly? | [
"https://pubmed.ncbi.nlm.nih.gov/9712135/",
"In the present longitudinal study, 20 deaf and 20 hearing children were observed during free play with their hearing mothers when the children were 22 months and 3 years of age. Compared to hearing children, deaf children were severely language delayed, with deaf 3-yea... | [
"Pretty big limitation there in studying only deaf children of hearing parents. Language development of deaf children in homes where sign language is the primary language could be rather different."
] | [
"I am giving an example from the NIH. There are many different ways to study children."
] |
[
"Could humans become nocturnal?"
] | [
false
] | I understand that under natural conditions attempting to be nocturnal can cause health problems, but would it be possible to use modern technology to do so with little risk? | [
"Well, a certain proportion of people are nocturnal. Read , nightshift workers. I have spent a not unreasonable amount of time in nocturnal mode. If you can work during the night there is a certain feeling of peace, not hearing the daily hustle and bustle , cars etc that comes from being awake during early hours... | [
"What do you mean by nocturnal? That is, would someone who merely stays awake all night qualify as nocturnal or do they require a built in mechanism that encourages them to stay awake at night?",
"It is quite possible for someone to sleep during the day and stay awake all night. Plenty of people do just that for ... | [
"This actually arose from a conversation with a night shift worker. He mentioned that although he is able to stay awake at night it doesn't quite feel right for him and that there is some evidence that it may be detrimental to his long term health. My question then, is if it is possible to adjust the bodies rhythms... |
[
"Is it possible for Big Bang theory to be false .Like Universe to expand only in our neighbourhood and staying constant or contracting elsewhere?"
] | [
false
] | [deleted] | [
"That wouldn't explain the cosmic background radiation (the discovery of which pretty much ruled out most other cosmological models at the time) and the abundance of elements in the universe (which can be explained with big bang nucleosynthesis). ",
"One could probably create additions to your hypothesis which ex... | [
"Why were you downvoted at all?"
] | [
"Nope, the universe is definitely expanding. We can determine the distances of faraway galaxies by using the brightness of a particular kind of supernova, and their velocities by using the redshift of their emission spectra, and the distance correlates pretty well with the velocity for every distant galaxy we've ob... |
[
"Atomic Orbital Theory, Molecular Orbital Theory, Valence Bond Theory."
] | [
false
] | What are the differences between these three theories? | [
"\"A scientific theory should be as simple as possible, but no simpler.\"",
"The standard model is our current understanding of particle physics and all interactions besides gravity. Everything is a field. Fields interact to produce the artifacts that we see. Everything is relativistically sound.",
"Quantum ... | [
"All three are models of the wave-particle duality of electrons in an atom, and are essentially related to one another. Atomic orbital theory is used to describe the energetic nature of electrons in a single atom; molecular orbital theory (related to VB theory) qualifies these wave interactions between multiple ato... | [
"I just finished up a group theory class that really tackled MO and VB theories. The major difference between MO and VB theories is that the electrons are delocalized through the molecule in MO theory, and confined to directly bonds in VB theory.",
"MOs can be found using group theory easily by ",
"1) determini... |
[
"What happens in my brain and/or body to make me feel drowsy?"
] | [
false
] | Are there any specific chemical or physical changes that occur in me that cause me to feel drowsy? This is especially interesting to me because it seems like the drowsiness kicks in all at once, like a bag of bricks hitting me in the face. | [
"While you are awake, adenosine levels increase in your brain, and past a certain level, adenosine receptor stimulation will make you feel drowsy. When you sleep, adenosine is broken down, reducing the drowsy feeling. Caffeine makes you feel less awake because it \"tricks\" your brain into thinking that there are l... | [
"So will drinking more coffee over a long period of time make me less sleepy in the evening? Funny enough I just wondered about that before seeing this thread. Would you mind having a look at ",
"this",
" please ?"
] | [
"See the post you linked for an explanation!"
] |
[
"What is happening to the reception of a Wi-Fi signal on my laptop when near an operating microwave?"
] | [
false
] | Hello askscience! This community has been very knowledgeable and easy to understand in the past (even to someone with only a layman's knowledge of many branches of science like myself), so I hope this answer to this question is painfully obvious. I noticed that my laptop's internet connection (to a wireless network) cuts out every I'm waiting for my lunch to heat up in a standard microwave. I assume that the microwave is radiating something to interfere with the wifi, but I can't imagine what. If it were actually "micro waves", wouldn't that kind of electromagnetic radiation be dangerous to people and thus be strictly contained inside the microwave? I'm hoping that some people can shed some light on this without super complicated jargon (I only have two 1st year physics courses under my belt). Thanks! | [
"Microwaves are only dangerous in sufficiently high amplitudes that they'll cause significant skin heating and thus burns. There's no physical difference between the microwaves emitted by your wifi and those emitted inside your microwave oven, it's just the energy level is orders of magnitude different. As KaneHau ... | [
"Microwaves generated by microwave ovens are generally around 2.45 gigahertz which is smack dab in the middle of the WiFi spectrum. To reduce this from happening, try changing to other channels to find one that is least bothered by the interference."
] | [
"Yes, they interfere with each other.",
"It isn't microwaves escaping the oven per say - rather, the electronics driving the microwave horn is oscillating at that frequency and generating radio interference.",
"Similar to how we used to debug computers in the old days (when computers were much slower). Back th... |
[
"Does at least one person in the world have to have Ebola (or any other virus) at any given time to make it continue on?"
] | [
false
] | null | [
"If a virus has a ",
"natural reservoir",
" (some plant or animal it can exist in), then it is not necessary to have a human infected at any given time in order for that disease to persist. This is especially pertinent to the ",
"Ebola virus",
" since natural reservoirs are being actively sought after to ex... | [
"Yes they are immune. And what you suggested has been tried and is the basis for the mouse antibody serum you've read about in the news. Unfortunately this serum while theoretically (and possibly really) is helpful in ramping up an infected individual's imm be system, it's not curative. "
] | [
"No, even if, and as is usually the case, no humans were presently infected with Ebola, the virus would continue to live on in its host animal(s). The Ebola family of viruses exist naturally without human involvement in the wildlife of Africa, originating with a species of fruit bat, I think. It's only when the v... |
[
"What is the difference between the magnetic pole and the geomagnetic pole?"
] | [
false
] | Wikipedia has too many fancy words that make no sense to me. | [
"The magnetic poles, or the magnetic dip poles, are the two points where the magnetic field lines are vertical, i.e., if you had a compass that allowed its needle to move in 3 dimensions, the compass needle would point straight down (or up, depending on which magnetic pole we're considering) when you were standing ... | [
"Really neither and there is a lot of nuance. The ",
"first chapter",
" from this book on paleomagnetism provides a (somewhat) approachable perspective. Specifically, in terms of the observed magnetic field (and thus the resultant location of the magnetic poles), a decent mathematical representation (but not ne... | [
"Does that mean there are two monopoles that make up the magnetic field or is it just like a bent dipole?"
] |
[
"What are the implications of the existence of the graviton - the force-carrying particle of gravity?"
] | [
false
] | The graviton is a hypothetical particle, probably massless, which carries the force of gravity and is responsible for its effects. in another thread is very illuminating. But what are the implications of this particle? In GR, sitting in a gravity field is equivalent to acceleration, relative to the reference frame of the massive object, correct? So the particle also plays an integral part of all the crazy time-dilation, space-warping craziness, right? And what about black holes? Clearly gravity can escape it, but not light? So gravitons are not subject to the effect of other gravitons, I take it? Then they wouldn't necessarily follow the same topology of the rest of the universe at the largest of scales, it seems to me - if the Universe is closed due to the effects of gravity, the gravitons would escape if they are unaffected by gravity... I just don't understand it at all! Finally, the most important question of all: if gravity is just another fundamental force, like light, for instance, do you think the possibility exists to someday construct a gravity laser? One which shoots gravitons in a collimated beam of synchronized gravity-insanity? What would it ? p.s. I suggest a name for this device: gravity-laser => gazer. Hah! | [
"Gravitons are just the quantized versions of gravitational waves, which we're pretty sure exist (based on the Hulse-Taylor binary). Gravitons are to gravitational waves as photons are to electromagnetic waves. The problem is that there isn't a working quantum theory of gravity, so gravitons don't work mathematical... | [
"I started writing one, but I realized I'm not fully qualified to answer so I stopped. So take this with a grain of salt.",
"Lasers are based on a transition between two electromagnetic states. Usually this involves an electron jumping from one orbital to another, which releases a photon. The gravitational equiva... | [
"Is it possible to make any comments on gazers without a mathematical model for gravitons?"
] |
[
"Can you trick a plant into growing faster by changing the duration of the day - night cycle?"
] | [
false
] | In the simplest terms: if I have a plant who has 6 hours of light and darkness rather than 12, so experiences two shorter days for every 24 hour period, would its growth be any faster? | [
"Maybe. It depends on what you mean by “growth”",
"If you mean “net uptake of carbon dioxide fixed into carbohydrates”, then probably not. Net uptake is a product of temperature, water, light, and CO2 limitation, and that won’t change by changing day length.",
"But day length is a critical component of hormone ... | [
"You can ",
" when day and night are, so your plant gets light when the environment is night.",
"Environmental CO2 levels peak at night, and noticeably so."
] | [
"If I have a plant who has 6 hours of light and darkness rather than 12, so experiences two shorter days for every 24 hour period, would its growth be any faster?",
"The plant wouldn't enjoy this at all. Most plants and animals are specifically adapted to Earth's 24-hour daylight cycle through a biological circad... |
[
"Are there any countable continuous sets?"
] | [
false
] | null | [
"Depends what you mean by a 'continuous set'. The notion of continuity is usually tied to topology and is used to describe mappings, not sets.",
"In topology, we make a classification of some subsets as 'open', and from this classification we can derive concepts like continuity (of mappings, not sets), closed set... | [
"Same story there though, it's absolutely possible, in carefully chosen topologies, to have finite dense sets. Just not in the topology of R."
] | [
"What's wrong with Q? That is dense."
] |
[
"Why is my paintball bruise a ring with an undamaged center?"
] | [
false
] | image: | [
"Just as an off-the-cuff direction to go with your thinking:",
"You know how when you squeeze a paintball between your thumb and index finger it bends (Unless you are using marbleizers...things may have changed since I've last played, but seriously, fuck those things)?",
"Well, you can imagine with the force of... | [
"Ultra slow motion Video demonstrating how the edges of projectiles impact radially outward (cool vid to watch just on it's own) ",
"http://www.youtube.com/watch?v=QfDoQwIAaXg",
"Edit: After watching the vid again it's almost like seeing fluid dynamics demonstrations when dealing with such extreme speeds and fo... | [
"Makes sense. I would also guess that it has to do with the fact that the center only experiences a compressive force, while the ring around the center gets more stretching/shear forces, which may be better at tearing capillaries. "
] |
[
"Is a sonic boom most intense at Mach 1?"
] | [
false
] | [deleted] | [
"A boat on a lake at constant speed leaves a V wake. A faster boat leaves a narrower wake. The speed of the ripple is like the speed of sound. That is your cone! Sound at Mach 1 spreading out as the plane rips past."
] | [
"Let me know if I'm wrong, but by how you proposed this \"addition of sound waves\" I'm guessing that you are thinking as the sound waves as the way the actual (audible) sound is propagated through space. That is totally correct but it's not actually sound what fluid dynamicist are referring to when talking about t... | [
"Ignoring for a second that your hypothetical wave would only have constructive interference directly in front of the aircraft and not for any observers of the craft, no because that’s not really how supersonic works. ",
"Supersonic aerodynamics is much more complex than most physics teachers have lead people to ... |
[
"How does the DNA replication machinery know when it has already replicated a chromosome?"
] | [
false
] | Before mitosis, cells undergo DNA replication to generate two copies of each chromosome. How is the DNA replication machinery controlled such that it knows when a chromosome has been replicated. In other words, what stops it from over-replicating a chromosome? | [
"Cyclins are a type of protein closely related to telling our cell when to start the DNA synthesis phase of the cell cycle and regulating it. More specifically Cyclin E promotes/initiates the assembly of protein complexes that actually do the replicating. Then another type of Cyclin called Cyclin A comes in, and se... | [
"The crux of preventing re-replication in eukaryotes works through the helicase, the enzyme which separates the two strands of DNA for the replication machinery. In a nutshell, the way this works is that the helicase is only capable of being loaded onto DNA during G1 phase. Once you've entered S-phase the necessary... | [
"Got it. Thanks!"
] |
[
"Why are smaller atoms generally more electronegative?"
] | [
false
] | [deleted] | [
"Less electrons on the outside shielding the protons, thus attracts more electrons more effectively."
] | [
"Electronegativity is the tendency for an atom to attract a disproportionate number of electrons in a covalent bond. As such, it is obviously affected by charges. The nuclear charge of the nucleus in small atoms is obviously smaller than in larger atoms, but they tend to have higher electronegativities on the whole... | [
"Right. As Jeebs says. ",
"Imagine yourself as an electron in an atom in two situations:",
"1) with a nice attractive nucleus close to you; \n2) a nice attractive nucleus further away with a cloud of unattractive electrons in the way. ",
"In which situation are you more attracted to the nucleus? The first one... |
[
"Can dogs (or other animals) go crazy if left alone in a small room for an extended period of time with no social interaction?"
] | [
false
] | null | [
"That's not 100% true. Most of the time dogs destroy things when left alone at home it's due to anxiety and stress caused by under stimulation. It has nothing to do with \"social interaction\"; an appropriate set of toys would serve the same purpose as having a person or another dog in the house.",
"tl;dr - Dogs ... | [
"This is actually a major reason why dogs destroy things at home while their owners are at work. It's not full on insanity, but it's an extremely negative behavior brought on by being left alone."
] | [
"Social interaction is a type of stimulation though, yes? Sure if you leave your dog at home with stuff to do he will likely be entertained. my dog usually sleeps when I'm not home and he's never been destructive from boredom, so it certainly is not a hard and fast rule.."
] |
[
"Why can't we simulate gravity?"
] | [
false
] | So, I'm aware that NASA uses it's so-called "weightless wonders" aircraft (among other things) to train astronauts in near-zero gravity for the purposes of space travel, but can someone give me a (hopefully) layman-understandable explanation of why the artificial gravity found in almost all sci-fi is or is not possible, or information on research into it? | [
"In addition to using centrifugal force to simulate gravity you can also use linear acceleration. If your spacecraft can sustain accelerating at 9.8 m/s",
" for a long period of time the occupants inside the spacecraft would experience a force equivalent to gravity in the opposite direction to the acceleration. "... | [
"Observed from the spaceship, accelerating at 1g would reach 0.77c after 1 year.\nObserved from Earth, it would take 1.19 years, and would have travelled 0.56 light years.",
"After two years on the ship at 1g, you would reach 0.97c, however 3.75 years would have elapsed on Earth and you would have covered 2.90 li... | [
"Just to be clear, the aircraft NASA use to simulate weightlessness are not in any way \"generating\" zero-g or removing the force of gravity. They are simply free-falling toward the Earth. Gravity is pulling them down, but there is nothing stopping them from accelerating so they experience the sensation of weightl... |
[
"How does brain control heart rhythm in people that are from neck down paralyzed?"
] | [
false
] | If a person is paralyzed due to serious injury to their spinal cord around neck, how does the brain still control the heart or even simple breathing is possible? | [
"It doesn't, at least not directly. The heart has its own internal pacing system that takes over. This is actually a real problem around the time of the injury, as the patient may be in shock from their trauma but the body can't manage to mount a high heart rate because the nerves have been severed. The brain can i... | [
"C4 is only a couple inches from the bottom of the skull.",
"The brain doesn't just receive information in nerve form, it also has chemical, hormone, and pressure receptors."
] | [
"The Vertebra are named based on the region of the spinal column they're located in and their place from top to bottom within that region. For example, there are seven cervical vertebrae designated C1 through C7. The eight cervical spinal nerves are similarly named. ",
"Here's a schematic showing all of them, an... |
[
"Why isn't fiberglass as dangerous as asbestos seeing as they are both fairly similar fibers?"
] | [
false
] | null | [
"fiberglass is man made, we melt and make glass into thin strands (1-10 micron usually).",
"Asbestos naturally forms extremely tiny crystals which are a lot smaller than fiberglass.",
"Fiberglass is still really dangerous and you shouldn't abrade it without proper ventilation and PPE. We have a carbon fiber sh... | [
"As I recall, the real issue with some forms of Asbestos is that it can cleave down to atomic scale fibers. This is what allows it to do the DNA damage, and cause cancer. Fiberglass (and other silicate materials will cause issues (silicosis), but afaik, won't have the cancer issues that Asbestos can have."
] | [
"In addition, I read somewhere that one of the problems with asbestos fibers is that when macrophages try to engulf and digest them, they are unsuccessful and they end up just impaling themselves on the fibers and then dying. The punctured macrophages then spill their cell contents which include reactive oxygen spe... |
[
"How did humans figure out that the ocean tides had anything to do with the moon?"
] | [
false
] | Early humans certainly realized that tides occurs with predictable regularity. And they knew that the moon had a predictable, regular cycle. But it's not nearly as obvious to the naked eye that there is a causal relationship between the tides and the celestial body hanging out in the sky. When did we figure out that the moon causes the tides, and what proved it? | [
"The tides tend to get stronger and weaker in about a two-week cycle, exactly half the cycle length of the Moon. You can follow that pattern over years or even decades, and it's always linked to the Moon. Full/new Moon: Large tides. Half moon: Small tides. Pretty obvious that they are connected somehow."
] | [
"There will always be a high tide within a few hours of the moon reaching its highest point. Depending on the lead or lag caused by the local geography.",
"Coupling this with the observable king tides when the moon is new or full, coastal communities rightly assumed there was a connection.",
"So as others have ... | [
"A little tidal history!",
" ",
"The earliest evidence for at least a practical understanding of the tides dates back to 2500-1500 BC in the form of a tidal dock at ",
"Kathiawar",
".",
" ",
"There is evidence, of a controversial nature, for humanity's understanding of the relationship between the tides... |
[
"Microscope to look at pond life?"
] | [
false
] | null | [
"Biology"
] | [
"Biology"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"If you disagree with this decision, please send a ",
"message to the moderators."
] |
[
"Do you think consciousness could be quantum mechanical?"
] | [
false
] | null | [
"Hi Fxck_its_demii thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the ... | [
"I've been asked to add flair to this post, I tried to leave my question an minimal as possible so as to not look like a moron. I was just wondering as I had watched a video recently on YouTube about this person asserting that consciousness is quantum mechanical, I wrote it off as they provided no evidence. But jus... | [
"Such questions are better suited for our sister-sub ",
"/r/asksciencediscussion",
". Please post there instead."
] |
[
"What is the current limit of CRISPR/Cas9 technology in human gene-modification?"
] | [
false
] | How far can we go with the current tech and the current understanding of human genome in terms of human modification? Without concerning ourselves with legal and moral issues, how much can we change a human embryo? What is the strongest positive change we can make with the current tech? | [
"The main challenge with using CRISPR to make the sorts of changes that people are imagining is that you need to deliver it to relevant cells, which is far from easy. The CRISPR cassette is fairly large, too large to fit comfortably in most AAV or lentiviral vectors. Adenoviral vectors are immunogenic issues, and e... | [
"What if you are doing an alteration to a zygote? As I understand there are just few cells there, which should make altering all of them easy. At this stage is it possible to make alterations to a zygote with CRISPR?",
"Yeah, zygotes would work, if you didn't mind accidentally killing some of them during the proc... | [
"So the only thing that's stopping us are legal boundaries.",
"And time and money. Sperm might be a dime a dozen, but human ova are time-consuming and expensive to acquire. ",
"Although, as far as I know some countries permit human gene editing in embryos (correct me if I'm wrong)",
"IIRC, the only people who... |
[
"I'm wondering what the brief history of cleaning and sanitation products is. Is there any sort advances coming soon?"
] | [
false
] | I assume surfactants have been known about for a long time (how long, I'm not sure). But other cleaning and sanitation products, I'm not sure about. And is there any discoveries or anything like that which will be coming to us soon? I don't really know chemistry or compounds, so a layman explanation might be best :) | [
"Mr. Clean Magic Eraser",
" is a pretty recent and awesome cleaning development."
] | [
"In terms of history a recent invention has been the application of enzymes in laundry detergent. The enzymes digest protein, organics and other stains. Now it may seem trivial to add these but they were a significant development. They required isolation, purification and a lot of modification to work in the washin... | [
"There's this research project with 3 sea shells that looks promising...",
"=)\nThe new nanomaterials are the next big advance. Nanoparticle siliver is already being used as a way of preventing microorganism growth. Hopefully the next big thing will be \"lotus effect\" surfaces, super hydrophobic surfaces that th... |
[
"Why do whales plunge out of the water?"
] | [
false
] | Most of us have seen the iconic hop of whales out and back into the water, causing the ships of many fictional characters to become surfboards. Why do they need to do this--is it simply to breathe, or is it tied to a hunting strategy or a mating call? | [
"Interesting theory, but dolphins also jump in and out of water, and for them it would not produce enough sound to travel long distances. An often neglected hypothesis for animal behaviours is just that the animals are having fun, but its nearly impossible to prove that is the reason for any animal behaviour. I won... | [
"Interesting theory, but dolphins also jump in and out of water, and for them it would not produce enough sound to travel long distances. An often neglected hypothesis for animal behaviours is just that the animals are having fun, but its nearly impossible to prove that is the reason for any animal behaviour. I won... | [
"Dolphins also use this for hunting. If you look into large baitballs, you can see dolphins on the ends of their hunting lines jumping out to signal where the end of the baitball is so that the rest of the hunters can work together easier."
] |
[
"With the current world birth rate at about 1 every 8 seconds, when was the last time we could say there was \"one born every minute\"?"
] | [
false
] | Try as I might, I have not been able to find a historical record of this. Source: EDIT: One every 8 seconds for the US, the world is about one every 2.5. | [
"Are you refering to the idiom of \"A sucker born every minute\"?",
"If so we need to define the percentage of newborns that would be considered suckers.",
"Borrowing snusmumrikan's data of current birth rates and required births per year and making the (hugh) assumption that birth rates have been relatively co... | [
"At birth, it is difficult to distinguish, so everyone must be considered a potential sucker."
] | [
"Where are you getting the one every 8 seconds data? ",
"The data from the UN I've just looked up seems to suggest 2.5 births per second.",
"I tried to do some quick rough maths to answer your question but it means finding a year with half a million births, which will be so long ago there won't be any reliable ... |
[
"Why cant we just cure dental caries/tooth decay?"
] | [
false
] | Given that tooth decay is due to bacteria ( and ), why can't we just get rid of those using something like antibacterial tooth paste? We're almost rid of several bacterial diseases in the west, for instance leprosy, cholera or typhoid infections, so why isn't anything done about tooth decay? Sure, it's bad for dentists, but there has to be someone out there willing to do something about it. | [
"I notice this source doesn't link to any peer-reviewed journal articles on the matter. Is this a result published in a reputable journal of medicine, or just a blogger making an unsubstantiated claim?"
] | [
"You mean like a ",
"vaccine",
"?"
] | [
"The oral microflora contains many of the disease causing bacteria normally. Example: what we call in dentistry as the red complex: p. ging, t. Forsynth, and p. Dent are found together in most cases of gingivitis, periodontitis etc. but a normal person might have one, two or all three of the bacteria and be fine. ... |
[
"Is voter apathy a relatively new phenomenon and does it exist and/or have repercussions in countries with compulsory voting?"
] | [
false
] | null | [
"Voter apathy is as old as democracy. In Athens, they used to send out slaves carrying a ",
" rope dipped in red ochre to round up voters from the agora. Anyone who tried to avoid attending the assembly (ekklesia) would have their clothes marked with the red paint, and could later be fined for failing to do their... | [
"OK, so I'm preparing for my comprehensive exams in political science, so I'll take this opportunity to address the question in terms of the literature that has been done on it (mostly relating to rational choice theory). ",
"In regards to 'apathetic voters' Downs (1957) would argue that it is quite irrational to... | [
"Part II:",
"In terms of the probability of influencing the election and its effect on one’s propensity to vote, researchers have reached diverging explanations on the matter. For instance, back to Riker and Ordershook, they found that primary elections in the previously Democratic-dominated South experienced hig... |
[
"What are the physiological mechanisms involved in the expression of complex mammalian coat patterns?"
] | [
false
] | As far as I understand, some patterns are influenced by temperature (siamese cat), while others (female, calico cat) result from the random inactivation of one or the other X chromosome which each contain one of two different alleles of a gene that determines color. Unless this is entirely incorrect, I think I have a good understanding of these mechanisms as they are frequently used examples, so I'm not looking for more information on these patterns. What I am interested in knowing, however, is how more complex patterns occur consistently throughout a species. One example would be in which seem to have circular clusters of spots around slightly larger, lighter spots, especially on their backs. I'd also be interested in learning how expression of complex patterns of spots might be similar or different to expression of stripes, such as those found on a . Thanks! | [
"I'm having trouble figuring out exactly what you're asking. Are you just wondering about the how the gene expression and physiology work to create the patterns? Here's some of my knowledge on the subject:",
"As far as pigment goes, there are genetic pathways that convert one pigment into another. But the pattern... | [
"I guess I'm asking what signals are involved in turning on genes coding for one color or another, and how they are precisely localized to form patterns. I understand how gene regulation works in general and how these patterns might evolve over time, but I'm curious as to how these genes are turned on and off in s... | [
"If you're familiar with developmental gene regulation I think you have all the answers you need. You might be thinking it's more complex than it really is, which it does seem like it could be something interesting. Think about the gradient mechanisms that ensure that hox genes (and others, of course) are activatin... |
[
"What is a Tachyon?"
] | [
false
] | What exactly is this particle? | [
"\"Tachyon\" is a catch-all term for any particle which travels faster than c. Nobody has ever observed one, and most physicists probably don't believe they exist."
] | [
"It's worse than that. In quantum field theory the presence of a tachyon corresponds to an unstable equilibrium. The mass squared of a particle corresponds to the coefficient in front of the harmonic potential in the field theory description, positive mass squared means you're at the bottom of a valley but negative... | [
"Although a group in Italy thought they did for a few months in 2011!",
"(turned out to be the result of a loose cable)"
] |
[
"Would it be feasible to have an electric car that was charged via solar panels built into it's frame?"
] | [
false
] | null | [
"The maximum solar energy available in any given area is limited to a maximum of around 1kW/m",
" In space it can get up to 1.4kW/m",
" but the atmosphere attenuates it a lot. The average energy available due to cloud cover and day/night cycles is 140W/m",
" The average car engine can produce around 100hp (76... | [
"And, sadly such a big solar panel system would be heavier and larger than your average car so it would need more power to move, and even more area for solar panels. So put on some more, but then your car is larger and heavier...damn."
] | [
"In addition to the other replies, concentrators save you the cost of the solar cells themselves but you still need a large collection area. If you're collecting energy from the same area and concentrating it onto a small cell, then you still need some sort of lens covering your car. This would again cause issues... |
[
"Has a non-native species of animal or plant ever been introduce into a habitat and it actually have a positive effect?"
] | [
false
] | Recently read about non-native ants in hawaii and how they’re threatening native Hawaiian butterfly species. It got me wondering if a non-native species of animal or plant has had a positive effect on a certain habitat. | [
"It’s almost unilaterally an awful outcome. ",
"Australia had a rich history of f*#king their ecosystems up with this! ",
"Cane toads are the prime example, rabbits, cats and foxes have done absolutely incalculable damage. Possums we’re taken to NZ from Australian, they have no native mammals so the possums hav... | [
"Relaunching the everglade (florida) panther was interesting. They brought in 8 panthers from texas to restart the population. ",
"NPR Florida Panther",
"Another one is the moose of newfoundland. They originated from 4 released over 100 years ago. Moose is now a staple of newfoundland population and culture. ",... | [
"Moose have had negative impacts on Newfoundland forests, as well as putting pressure on native caribou populations, both by competing for resources and by providing more food for coyote populations.",
"Degradation of Boreal Forests by Nonnative Herbivores in Newfoundland's National Parks: Recommendations for Eco... |
[
"Is the leaf-like structure of the Leaf Katydids actually leaves or the material that leaves are made out of?"
] | [
false
] | Upon observation of Leaf Katydids, it appears that the leaves on their bodies resemble actual leaves of a tree, to the point where they look brown, have holes in them, and other things that commonly happen to leaves. Is the cellular structure of the leaves on their bodies the same as the leaves from the trees they hide in? If it is, does that mean they can use chlorophyll to synthesize sunlight and water into a sustainable food source? | [
"The katydid's wings are made out of the same material as the rest of the insect's exoskeleton, which is chitin. That's an animal protein that makes up the exoskeletons of all of the insects and other arthropods. That protein is also found in mollusks, in the radulae of the gastropods and the beaks of the cephalopo... | [
"Very interesting. Thank you for your response! "
] | [
"I was of the impression that there are very strong differences between animal and plant cells.",
"Like this: ",
"http://img.sparknotes.com/figures/9/93c5cab1f150fcaaa9f2533d0a0b45c2/plantanimal.gif",
"Is it possible for any organism to have both?"
] |
[
"What changes when you break the sound barrier?"
] | [
false
] | Do things feel different, act different, sound different, etc? Or is everything similar to traveling at subsonic speeds? | [
"Nope nothing changes. There are many pilots who have talked about this online, but from the cockpit nothing feels different (other than a small shudder when initially break it). Some have described it as quite disappointing actually."
] | [
"Nothing really changes from the views of a pilot however there are some really cool changes that occur within the machinery. If you look at any jet engine you notice the cone shape of the engine output. The jet engine pushes gases into an hourglass shaped funnel. As the funnel contracts the velocity increases. The... | [
"Not the answer i was expecting but still good to know. Thanks!"
] |
[
"Does the water in clouds cause drag on aircraft?"
] | [
false
] | Obviously there’s quite a bit of water in clouds in any size from vapor to rain drops, as aircraft go through this does it have any effect on power requirements due to increased drag? | [
"In short, not really. The liquid water content in a cloud is rarely more than a few grams per cubic metre. Compared to the density of air (~1.2 kg/m",
" ), the water has little influence. And since clouds consist of tiny droplets, most of the water will just flow with the air, and only a small fraction ends up a... | [
"Clouds have the same average density as the surrounding air at the same altitude. They have to, otherwise they would go up or down."
] | [
"The presence of water can cause icing on the aircraft, which can indeed increase drag and in addition cause premature stalling as the ice can cause flow separation to occur sooner (the texture of the ice is rougher than that of the aircraft skin)."
] |
[
"Wish I'd gotten a pic of the bottom which is bony and has horn like protuberances. What the heck is this?"
] | [
false
] | It was found in a coastal region so I'm guessing it's some sort of marine animal... It's been identified as Black Drum Pharyngeal Teeth. Thanks, 30000. | [
"I have a buddy who found something similar in the water on the Gulf Coast. So I asked reddit about it here:",
"http://www.reddit.com/r/animalid/comments/jqyhh/can_anyone_identify_this_thing_that_came_out_of/",
"The best answer that I got (and still not sure if it's correct, btw) is that they are pharyngeal tee... | [
"I agree. Do we have one handy? Is there an ichthyologist in the house?"
] | [
"I've seen these before while in a marine biology class on the shore (not an icthyologist) - it functions as a grinding plate for fish. betta fish have them - you can see and hear it working when they grab a 'kibble', and their head moves up and down"
] |
[
"Does the moon have tectonic plates like the earth does?"
] | [
false
] | null | [
"No. The Earth is largely unique in the Solar System with the presence of plate tectonics, although Mars may have briefly had it in its past.",
"Plate tectonics requires that the body remain hot long enough for the interior to convect and keep the crust moving. The moon, being relatively small, was not endowed wi... | [
"Mars may have briefly had it in the past.",
"What happened? Did they fuse together? Could that happen to Earth's?"
] | [
"As the planet's core cools, the molten rock gradually solidifies so in essence, yes, if Mars has plates then when the core cooled they stopped moving and became a solid mass.",
"That will eventually happen to Earth as well, but we have a looooooong way to go before the core cools sufficiently. Estimates vary bec... |
[
"Besides C-14 and other forms of radiometric dating, which other techniques are used to determine the age of fossils and bones?"
] | [
false
] | C-14 dating can be used to date animal and plants remains that are less than 62000 years old and other forms of radiometric dating require the presence of igneous (volcanic) rocks. Which methods are used for dating when these techniques are out of the question? EDIT: is the reason for my question. "To everyone's surprise, the bone was part of a remarkably complete skull and upper body of a child that died 108,000 years ago, " | [
"Most are dated using ",
"relative dating",
" and then tied to an absolute age using methods of radiometric dating (dating igneous rocks within a sedimentary sequence, for example).",
"Using fossil succession is a very powerful method commonly used. This is done by observing the entire fossil assemblage, i.e... | [
"Now that I see your particular interest, I suspect they used U-Th disequilibrium isotope dating, paleomagnetism, or thermoluminescence. I can find no references other than the fluff piece you link, so it is impossible to say. In future, I'd appreciate knowing the specific question up front."
] | [
"One somewhat obscure technique is thermoluminescent dosimetry. It is rather complex to describe, but a university library might have a decent book (McKeever wrote a decent one a while back).",
"Edit: Quick description... radiation causes certain materials over time to have electrons move to relatively stable hig... |
[
"Is there a link between unemployment and death?"
] | [
false
] | null | [
"There have been multiple studies over the years that have found some significant relationship between unemployment and suicide rates, but there are also a lot of variables that can impact those results, since life is a rather complex and multilayered thing in modern society. ",
"Here are a few studies I've foun... | [
"There are a lot more factors than just suicide. Unemployment can be an indicator of an economies overall health and declines in the economy can impact many aspects of life. On an individual level, less $ means reduced access to healthcare, unhealthy food, increases in mental health disorders etc. On a societal lev... | [
"This is a very important question right now as the world balances the decision of when to return back to work. If we wait too long or return to early the consequences could be enormous. With almost 17,000,000 applying for unemployment in the last three weeks, or about 10% of the workforce, the answer to this quest... |
[
"Can someone explain the concept of quantum computing?"
] | [
false
] | From what I know, classical computing uses two states, 1 and 0, true and false. Quantum computing is not limited by two states and thus can process values much faster. My question is, how would this even work (not practically, but I want an explanation behind the theory)? | [
"There are lots of really bad explanations of quantum computing floating around. (For instance, it's often claimed that a quantum computer can let you \"try all possible solutions at once\" which is almost entirely wrong.) ",
"Here's a layman's explanation by complexity theorist Scott Aaronson."
] | [
"Check out the ",
"Bloch Sphere",
".\nIt is essentially a single qubit which has an absolute, whole, existing value. But the constituent parts of it are in probabilistic terms. That is, what defines the digital quantum information in a single qubit is from observations and measurements of changes at a quantum s... | [
"Correct me if I'm wrong.",
"Rather than classical computing's use of square waves in order to have a set of 2 states, quantum computers use a full sinusoidal probability wave which, through some means (the computing itself), constructively interferes with the correct answer. Likewise, incorrect values are destr... |
[
"If I submerge a jar under water, will the water flow constantly in and out of the jar?"
] | [
false
] | Or would the water that's in the jar be stagnant? I'm hoping the answer is that yes water would be slowly moving in and out of the jar. What about water that's closer to the bottom of the jar? There is current in the main pool of water flowing slowly over the jar and the jar is about 2-3 inches below the surface. Its a tall coffee jar. | [
"The jar will shield most of the movement from its contents, but you will get some slight exchange in and out. If you want to see it happen, pull some water with food coloring into a straw (to the top of the straw), put your finger on the top of the straw, insert the straw to the bottom of jar while submerged and ... | [
"If there's a current flowing over the open part of the jar itself, then there certainly will be some exchange - the open mouth of the jar will create some turbulence. How much and on what time scale, though, is not easy to predict, because turbulent flow of liquids is one of the hardest things to model. It could w... | [
"make sure there's no air in the jar....like none....as the air will cause turbulent mixing"
] |
[
"What exactly happens to an atom as we increase the strength of a hypothetical magnetic field?"
] | [
false
] | Do the quarks all experience forces in different directions due to their velocity and the atoms are either crushed together or ripped apart? | [
"The most exciting thing that happens to an atom in the presence of a (static) magnetic field is the Zeeman effect, where some of the energy levels for a given electron shell are split. ",
"This turns out to be an extremely useful effect for a lot of applications, but unfortunately it's not nearly exciting enough... | [
"The effect applies to nuclear energy levels too!"
] | [
"No. Will edit with answer when I get to a computer at work.\nEDIT:\n\"In particle physics, the strong interaction (also called the strong force, strong nuclear force, or color force) is one of the four fundamental interactions of nature, the others being electromagnetism, the weak interaction and gravitation. At a... |
[
"What are some good TV shows on science?"
] | [
false
] | I'm not sure this is the right subreddit. Sorry, if this subreddit was not intended for these types of questions. I was watching the following, but they're either canceled or on break: I didn't add Nova ScienceNOW, because I just simply can't find the episodes for download. :( Anyone know any similar TV shows? EDIT: To keep the list going, here's what you've recommended so far: | [
"Not really a tv show but if you haven't watched it yet I suggest you watch\n",
"Richard Feynman's Fun to Imagine",
". Really interesting stuff about physics. "
] | [
"Cosmos by Carl Segan was good"
] | [
"\"Segan\" ",
"ಠ_ಠ"
] |
[
"What is the brightest light on Earth?"
] | [
false
] | Hello reddit, I just saw another space post by someone on the ISS. Some areas on earth at night are obviously brighter than others due to being clusters of lights in cities. I now wonder, what light on Earth is the most noticeable from space. It's almost like looking for the North star, except on Earth. | [
"Well, the north star is not particularly bright in the scheme of visible stars in the night sky. It ranks somewhere near 50th for brightness. ",
"But for the question if the brightest \"light\" on Earth, it depends on your scale. The brightest city is most likely LA. The brightest city section is reported to be... | [
"Follow the citation: ",
"http://www.lasvegasnow.com/news/the-story-behind-the-luxor-light/79163434",
"The first thing you learn at the top is that there is no giant light bulb. Instead, 39 individual lamps, housed in dark, sturdy reflectors sprout from the floor like a forest. They combine to create the light.... | [
"When at full power, the system costs $51 an hour to operate, with $20 per hour of that just for its 315,000 watts of electricity.",
"...Where does the other $31/hr go? Human salary?"
] |
[
"Is there any significance at all to Earth's position in the universe? Anything at all unusual? Or are we situated in a completely unremarkable neighborhood?"
] | [
false
] | null | [
"There is one significant feature of our position in the galaxy: we're in the Local Bubble. ",
"http://en.wikipedia.org/wiki/Local_Bubble",
"\nThis is an area of interstellar space that is relatively free of gas and dust, and allows us to see farther into the Universe than would otherwise be possible. It was ca... | [
"The only thing remarkable about the earth (aside from its life) is how unremarkable it is.",
"It is a medium sized planet. Orbiting a medium, unremarkable star. In a medium, unremarkable system. Orbiting in an unremarkable part of an unremarkable galaxy which is in an unremarkable cluster of galaxies...",
"But... | [
"I remember a couple neat things about our solar system that are fairly unusual... If I remember correctly, the fact that our solar system is a single star, and not a binary star system, is actually relatively uncommon.",
"Also, the fact that the moon happens to be the correct distance away from us to make a tota... |
[
"Why is U–Pb dating so effective in measuring the age of the Earth? Wouldn't there be decaying uranium floating around the early Solar System, or even *before* the formation of the Sun during the nebula stage?"
] | [
false
] | null | [
"Yes, there would. Then it all gets melted into a homogenous mess during planetary accretion. With the uranium locked in place, and the Pb unable to escape, we can measure their ratios to tell how long they've been locked in place.",
"Radiogenic dating tells you when the substance was last melted, not anything el... | [
"A small addition to say that we mainly date zircons in the rock when using uranium-lead dating. Not only is zircon particularly long lived and resistant (even for a mineral), but it incorporates U into its crystal lattice ",
". So any Pb must have come from the decay of certain U isotopes. ",
"There is also th... | [
"Radiogenic dating tells you when the substance was last melted, not anything else.",
"This isn't really accurate. Radiogenic dating tells you the time at which the system (here meaning both the mineral you're targeting and the parent and daughter isotopes you're measuring in that mineral) became closed, i.e. whe... |
[
"How do magnets lose their strength and can they be strengthened or remagnetized remotely?"
] | [
false
] | This is my first time asking on because I feel my questions will not be adequate enough. I apologize ahead of time for the potato question. When I say remotely, imagine a cylindrical magnet suspended magnetically in a tube lined with opposing magnets. | [
"I don' t understand exactly what you are getting at. Regardless of its environment, it is always possible to heat something up with enough power. Spinning a magnet in atmosphere would generate friction on the surface and heat the magnet up. Spinning a magnet in a vacuum will generate a small amount of heat due to ... | [
"A permanent magnet looses field when it is heated above the Curie temperature, or is impacted. A sufficient field can also force a change in the direction of the field in the magnet.",
"Permanent magnets are produced by heating the magnet above the Curie temperature and applying an external magnetic field using ... | [
"In a vacuum which would be a frictionless environment, could the magnet reach that temperature while spinning?"
] |
[
"Why do some allergies only affect certain parts of the body?"
] | [
false
] | Many allergies seem to only affect the respiratory system or the digestive tract. Why can the same allergen be rubbed on skin in some cases and no reaction occurs, or post stomach not cause reactions throughout the rest of the digestive systems? I am assuming there is no reaction after leaving the stomach due to the acid denaturing the protein responsible, but why is this the case for other parts of the skin/body? | [
"The antigens have to be bound to IgE and then end up activating immune cells (mast cells especially). That's just much easier to accomplish in the respiratory and digestive tract. Unbroken skin is an excellent barrier for entry, and the respiratory and gastrointestinal tract make up most of the rest of the barrier... | [
"Humans are donuts. The inside is also outside. (Same with most animals.)"
] | [
"True allergies are related to mast cell activation where histamine is release as a response to the allergen. The sequence of bodily reaction to the allergen is related to the release of histamine. Example: peanut allergies and swelling of your tongue etc",
"In sensitivities, other immune factors are released so... |
[
"If the bodies of rodents spasm when shot in the head, wouldn't that mean that a human's body would also spasm if shot in the head?"
] | [
false
] | null | [
"depends on what part of the brain is hit. ",
"and yes people can twitch when shot.. sometimes for quite some time as random firings of a broken brain make their way to muscles. "
] | [
"You seem to be awfully familiar with the death-twitch of rodents... That's pretty creepy.",
"But it depends on which part of the brain is hit."
] | [
"Yeah, I wouldn't take too much of reality from what you see in video games.",
"I've killed lots of things, and shot quite a few deer in the head. They kick and spasm and do all kinds of things. Its unsettling: death is not pretty.",
"Even when you shoot through the heart and/or lungs a deer might run a hundred... |
[
"Why do celestial bodies spin? What keeps them spinning? Have we discovered any that don't spin?"
] | [
false
] | Celestial bodies meaning planets and stars. | [
"Because of conservation of angular momentum. Objects form from smaller stuff colliding and sticking together. ",
"If you have two or more objects, unless they collide head on, the final object has angular momentum and will be spinning. It's incredibly unlikely that anything in space was formed from objects colli... | [
"It does spin. It's rotation roughly matches it's orbital period around the earth"
] | [
"Just remembered what tidally locked actually means, thanks "
] |
[
"Is there a name for sine-like waves that are generated from shapes other than a circle?"
] | [
false
] | null | [
"I don't know of any special name for these functions, but the creator (",
"/u/lucasvb",
") of the .gif you have linked tends to call them \"polygonal trigonometric functions\". It's a bit of a misnomer since trigonometric already means \"having to do with a right triangle\", but in the absence of a better term... | [
"I particularly like that the region corresponding with the top-middle of the heart is smooth, but the one corresponding with the bottom-middle is sharp. Thanks for sharing."
] | [
"Polygonometic functions?"
] |
[
"What happens to one siamese twin when the other die?"
] | [
false
] | I read the case of Chang and Eng Bunker ( ) that when one died, the other one passed away few hours later. What caused the death of the second one? What happens in other cases of siamese twins? | [
"Hmm, I'm going to speculate...I'm willing to wager that not much is known about this phenomenon, since conjoined twins are extremely rare to begin with.",
"First off, I'm going to begin with the assumption that the twin's vascular system (blood supply) is joined. Now, if their hearts were separate, I would imagi... | [
"Eng survived some hours [... i]t is more likely that he bled to death into his brother through communicating vessels; during the embalming of their bodies it was found that Chang was suffused with blood while Eng was greathy depleted (Tempelton, 1993).",
"GoogleBooks wouldn't show me the references page, but I t... | [
"Do you think possibly when the first brother died, cell necrosis released toxins that killed the second? Thats the only thing I can think of; kind of like when you have severe frost bite, you have to remove the dying or dead flesh before it kills you..."
] |
[
"Why are Moths nocturnal if they are drawn to sources of light?"
] | [
false
] | I know that Moths wouldn't necessarily be drawn to a light source such as the Sun, and that during the day lamps and the likes aren't likely to be switched on, So I guess what i'm asking here really is, a) Why do Moths come out during the night? b) What is the difference between Nocturnal moths and those who appear during daylight hours? and c) what is it that attracts them to light sources? Is it for Heat?, or is that a misconception that I have? Thanks. | [
"Moths use light waves to navigate in the dark. Obviously before humans, the only source of light at night were the moon (within reason)\nNow,throw in artificial light and those motherfuckers get confused. Im sure some lovely redditor has the science behind it."
] | [
"That's pretty much it."
] | [
"Thanks man."
] |
[
"Why do lupus and fibromyalgia mainly affect women?"
] | [
false
] | I was reading up on both this morning (mother has fibro) and found out that in both about 90% of patients with either condition are women mainly in the childbearing age range. Is there any reason for this? Thanks. | [
"hormones have significant immune effects. Lupus and fibro (to an extent) are seen as autoimmune diseases. Estrogens are seen as immune-stimulating. Women in childbearing age have higher levels of estrogens. This is a really active area of research but there are far more unknowns than knowns since the immune system... | [
"If there are sex-linked genes involved then perhaps on the X chromosome are dominant genes that contributes to the disease. Females would have a much higher chance of expressing a dominant gene on the X chromosome since they have 2. If something happens during childbearing it’s likely a gene that is expressed in o... | [
"Isn't it known that in general women suffer more from auto-immune diseases while men suffer more from immune deficiencies?"
] |
[
"Were massive slabs of similar materials that make up the Earth, rock quarries for example, formed recently or at the beginning?"
] | [
false
] | null | [
"Entropy only increases in a system that doesn't have external energy. Luckily, we have the sun, which provides energy for the erosion and subsequent deposition of sediments, and we have radioactive energy coming from the mantle/core that provide upwelling currents in the Mantle.",
"Lets take your example of lime... | [
"To add to what GoeManCam has already posted, rocks have been formed continuously through Earth history. Right now in rivers, lakes, deserts, deep water, and all sorts of other environments you have sediments being deposited which can - over time - be buried, and eventually lithified (turned from loose sediment t... | [
"There are some rocks that are about 3.6 billion years old, and these are granites. One example is from Finland and western Russia. ",
"What about Isua? 3.7-3.8 Ga sediments and volcanics."
] |
[
"Does a herniated disc still show up on an MRI weeks or a month after the rupture?"
] | [
false
] | I would think a herniated disc, after a week or so when it's healing, would start failing to show up on an MRI because the nucleus would be mostly gone. EDIT: Didn't mean to start a religious medical imaging war :) but it is interesting for a layman like me to learn about the nuances. I think the answer to my question is "yes" based on the what was said. Thanks to all that replied. | [
"A herniated disc is simply one which has “pooched out” from the margins of the vertebrae into the surrounding tissue. In doing so it often impinges on nerves emerging from the vertebrae, causing pain. Main point though, a herniated disc is not necessarily ruptured. Yes herniated discs show up on mri. However they ... | [
"MRI is the correct modality for imaging herniation, effacement, stenosis and more. CT is better for imaging bone related issues, conventional radiography will show disc foreshortening, subluxation, scoliosis and more, that's one reason why they usually do standing obliques before they get to the scans. Most (thi... | [
"Not all herniated discs will show up on a CT. The MRI is best suited for water containing soft tissues such as discs and will be more effective for diagnosing hernias. CT scans are better at more calcified structures such as viewing bones and fractures. The CT is not as popular as it used to be, but still used fre... |
[
"If we attempt to land a space craft on say Europa, aside from hauling large amounts of fuel with the craft, is there another practical way to slow down, such as Aerobraking in Jupiter?"
] | [
false
] | Considering the speed the craft would need to get there in a reasonable time and in the case of Europa, carrying a large heat drill and submersible, the probe would have a very large amount of inertia, are there any other ways to slow down? Edit: I should have clarified, I mean any distant body without an atmosphere. | [
"We can use ",
"gravity assist",
" to both speed up and slow down a craft:",
"Due to the reversibility of orbits, gravitational slingshots can also be used to decelerate a spacecraft. Both Mariner 10 and MESSENGER performed this maneuver to reach Mercury."
] | [
"Cool, so something like passing (relatively) close the planet in a very elongated orbit and breaking orbit at the apoapsis?"
] | [
"Yep, pretty much. I'm sure that the orbital mechanics are slightly more complicated than that, but the main idea is that the craft must appear as having the same momentum both coming and going from the reference frame of the planet (conservation of momentum and all that jazz). This means that, from a different r... |
[
"How does a Whammy Pedal work?"
] | [
false
] | From what I understand, to change the frequency of an input signal requires multiplying it with a different signal. So on a Whammy pedal, if you’re pressing the pedal and the pitch slowly raises up to an octave above the input, are more and more signals being multiplied together the more you press down? Where are these generated from? Is there a digital shortcut to recreate this effect that I’m unaware of? | [
"You're talking about frequency shifting, or Single Sideband Modulation (SSB). It shifts the entire spectrum up or down by a fixed interval, in Hz. This is not what pitch shifters do, it's more similar to a ring shifter. ",
"The reason is that frequency shifting doesn't preserve harmonics, because it shifts every... | [
"I understand that a wah pedal is a BPF, but for a Whammy? I know signals are a combination of frequencies and harmonics but are guitar input signals always complex enough that you can isolate a component up to two octaves above the prominent pitch?"
] | [
"Now that you mention it, I was talking about wahs and not whammies! Doh!",
"Whammy pedals are pitch shifters renamed by marketing people. They're all digital now, so they work by math. The exact algorithms are trade secrets. But basically, they must do a Fast Fourier Transform (see wikipedia), copy the signal 1 ... |
[
"The asteroid belt...is it a sphere?"
] | [
false
] | I was thinking this morning that the solar system isnt flat, and if the asteroid belt which is commonly quoted (no reference) as one of the reasons earth hasnt been hit by any planet killing meteors, wouldnt it have to be a sphere, or is it on the same vector as Earth? (and even then, meteors can come out of anywhere (i think). | [
"The asteroid belt is pretty flat, you can imagine it like one of the rings of Saturn in shape. The reason for this is that all the planets/asteroids etc in the solar system formed inside a spinning ring of matter (an accretion disc) around the very young Sun, so are all orbiting roughly the same way (interactions ... | [
"The belt isn't as flat as Saturn's rings , but the bulk of orbits are within 15 degrees of the ecliptic plane. More of a flattened bagel starting just outside the orbit of Mars and extending about halfway out to the orbit of Jupiter."
] | [
"No, actually the solar system ",
" pretty much flat and the belt is in a plane with the planets. It protects us from asteroids which are pieces of left over failed planets (in very simple terms, they're more complex than that). However, the Oort cloud (at the edge of the Solar system) is pretty spherical and obj... |
[
"My Crabapple tree is blooming in the fall and we live in Alberta, Canada. This has never happened before and we've lived here for 10 years. What is happening? [pic]"
] | [
false
] | null | [
"That is odd. Apple trees flower in the spring. Has there been some odd weather there? Apple trees may flower after 50-90 days of growing days without a frost in the spring, but that would be weird in the fall. It appears that your tree has apples too.",
"Has your tree been grafted with some other cultivar? That'... | [
"The weather has been pretty dry, but we have been watering very consistently. The Crabapple tree is located on our front lawn, which has been green all season.",
"No grafting has been done.",
"The article you linked in the comment below was very interesting. Although, there was no mention of Crabapple trees bl... | [
"Alberta can get some weird climate activity, with unseasonal weather for weeks on end. What's the summer been like, there? It's possible that a period of cooler than average weather followed by warmer than average could have tricked the tree into behaving as if it were spring."
] |
[
"Are there any problems in Computer Science that *can't* be solved with classical computers but *can* be solved with quantum computers?"
] | [
false
] | It's already pretty well-known that certain classes of problems may have more efficient solutions (e.x. factoring primes) when using a quantum computer vs. a traditional one, but I was wondering whether there are any "unsolvable" problems that become "solvable" when using quantum computers? | [
"Actually, we've proven that there are no problems that a quantum computer can solve that a classical computer cannot. A classical computer can simulate a quantum computer so a classical computer can solve any problem that a quantum computer can, just slowly. ",
"Its still an open question if there are models of ... | [
"Not that we know of. Computational Complexity problems are all solvable with different kinds of resources. For example, problems in EXP take exponential space and time to solve, but are still 'solvable' in the sense that you are describing.",
"The class of problems that are 'unsolvable' are known as 'undecid... | [
"Just out of curiosity how is it possible that another model of computation more powerful than a Turing Machine would exist? Wouldn't that be self-evident?"
] |
[
"Since light is an Electro-Magnetic radiation, are photons as a light particles deflected when passing through strong Electric or Magnetic field?"
] | [
false
] | null | [
"Nope. Photons ",
" the electromagnetic field. The thing that measures ",
" with the electromagnetic field is a particle's charge, and photons don't have any. Photons don't directly interact with themselves (i.e. the electromagnetic field)."
] | [
"To be pedantic, at low energies they don't interact with one another, but at gamma ray energies and higher I believe, two photons colliding can produce a electron-positron pair. This is the time reverse of the electron-positron annihilation that produces energy."
] | [
"I just wanted to add that in a sense photons can interact with each other, through virtual electrons. While the existence of electrons (or other charged particles) is needed for this to happen, no actual (i.e. real, on-shell) electrons are necessarily involved in the process."
] |
[
"What helps Californium-252 become such a good neutron emitter?"
] | [
false
] | I read that Californium - 252 decays by alpha decay and spontaneous fission. But which of these contributes to Californium producing neutrons? | [
"Alpha decay is the emission of one helium nuclei ( 2 protons and 2 neutrons bound together) from the original nuclei.Ppontaneous fission usually produces 2 (or more in very rare cases) lighter nuclei than the original one plus 2-3 free neutrons. ",
"Cf-252 decays to 96.908% over alpha decay and to 3.092% over sp... | [
"Spontaneous fission. Every fission emits on average 3.7 neutrons. It has a reasonably high SF rate of around 3%. "
] | [
"This was very helpful. Thank you "
] |
[
"How can a speaker produce multiple noises at once?"
] | [
false
] | null | [
"Speakers work by the ",
"principle of superposition",
". If you want to hear two tones at once, just add their vibrations together.",
"When you compare the voice box the a reverse eardrum, you've got it exactly right. The voice box, in a given configuration, can only resonate at one frequency (and higher h... | [
"Vibrations 'add' together. What we normally think of as sound waves, are really pressure/displacement waves in air. The information in the wave is completely encoded in how much each air molecule has been displaced from where it was an instant ago. When you listen to, say, a Queen tribute band live in concert, you... | [
"I made a pretty successful answer to this same question about a month ago:",
"http://www.reddit.com/r/askscience/comments/m2v0f/how_can_a_speaker_produce_more_than_one_sound_at/c2xmyx4"
] |
[
"Does the binocular effect apply to dimensional projection?"
] | [
false
] | I've read a small amount on dimensional projection, as far as I can tell it takes rules that apply to the dimensions we understand and telescopes them out to explain each successive dimension. For instance, according to dimensional projection, a 3-dimensional object casts a 2-dimensional shadow. Therefore, a 4-dimensional object would cast a 3-dimensional shadow. So, kind of along this line, we can simulate a 3-dimensional object by layering 2 2-dimensional objects over one another. Could two 3-dimensional objects be layered over each other to create a 4-dimensional image? | [
"I see; so mathematically speaking, layering 2 (or maybe more) slightly varied 3d images over one another could \"fool\" the optic sensors of a 4-dimensional being, but as 3-dimensional beings these images would just be confusing. Thanks for your input"
] | [
"Kinda; It's possible to reconstruct 4-d information based on the 3-d projections of an object, mathematically speaking. But we don't have sensory input capable of handing 3-d objects. So we just end up with pictures like ",
"this",
"; The reason the binocular effect works with your brain is that your brain is ... | [
"Apropos, there are computer graphics that are meant to represent a ",
"projection in 3D of a 4D tesseract",
"."
] |
[
"If allergies are caused by an over active immune system, does that mean someone with bad allergies is more likely to get sick as their immune system is constantly \"preoccupied\"?"
] | [
false
] | null | [
"Saying that allergies are an \"overactive\" immune system is the result of an oversimplified explanation. It's not really overactive, it's dysregulated.",
"Imagine you are traveling in a car driven by a trusted friend at 50mph down a road in California. Everything is good and you are on your way to an intended d... | [
"So expanding on MolecularBio's question, in the dysregulated situation, does this inappropriate reaction mean that the body's immune system, specifically the functions which are part of the allergy response, leave the body less able to respond to other pathogens? For example (and even this might be confusion on my... | [
"Does having an allergic reaction during pollen season leave the body less able to \"fight off\" a cold virus?",
"I don't know of any studies that have looked at this directly, but my initial (and somewhat speculative) response would be to say that it may increase your ability to fend off a cold virus, or at leas... |
[
"Would a child naturally learn bipedal ambulation?"
] | [
false
] | If a typical child were somehow raised by robots (assume they have wheels or levitate), would that child naturally learn to walk on two feet with an upright stature without having an example? | [
"This has been asked before. Last time I tried to argue that children would continue crawling, and I used some reports from feral children to make my case.",
"Long story short, there's no evidence that children would continue to crawl."
] | [
"There are central pattern generators in the spinal cord which are 'pre-programmed' with the alternating gait of bipedal locomotion. I have not seen evidence that the same thing exists for our arms (though a lack of evidence is not evidence for a lack of something), which would be indicative of an inborn propensit... | [
"Much of this is hypothetical... but that may be the best you get for this answer, as to my knowledge there is no definite answer to this question.",
"One component towards reaching a plausible hypothesis to your question is the fact that (to a certain extent) walking is a spinal cord reflex. ",
"As in, at a ",... |
[
"Obviously, I'm not a golfer..."
] | [
false
] | A couple years ago I was having an online discussion with someone about man's responsibility in Global Warming and I came across a bit of a pickle. Now, I'm a complete layman, so I tried my best to explain the greenhouse effect and whatnot, but eventually this guy pulled out something I wasn't expecting. He told me it was all a cycle - something I had already heard before -- but one that could be explained by water currents. was something I wasn't sure how to respond to. Here's what I have saved from back then: Here's why we shouldn't fear Global Warming: The ice caps melt. The ice caps release freshwater into the ocean. The freshwater slows down the ocean currents due to its density. Less warm water reaches the poles from the tropics. Over time, and with enough fresh water released, the poles freeze over due to the lack of warm water from the tropics. This is how an ice age naturally happens! (This is what happened during the Little Ice Age.) The tropics heat up and eventually melt all the ice. Water currents aren't really my forte. So, did this guy go wrong in his logic? If so, please enlighten me. Made an error. He wasn't saying that's how Global Warming happened, he was trying to convince me that we shouldn't fear it. | [
"Does it being a cycle make it any less deleterious?",
"And if humans are really rapidly increasing the rate of the ice caps melting, how is that an excuse to say it's okay?",
"Tell your friend that you heard he was going to fall asleep tonight and then tell him not to be mad at you when you drug him and he pas... | [
"The problem with things like that are you aren't quantifying any of the results, you don't know how much the currents are being affected, or how this affects refreezing, or any of the other stages.",
"It's kind of like saying that I walk around all day and get hot. If I attach a turbine that is moved by my walki... | [
"No, water currents do not control global climate. They do redistribute a huge amount of heat, though, and have big effects on local weather and climates around the world. They also have various feedback effects on the climate system, which I don't know enough to tell you about off the top of my head (and which ar... |
[
"Do non-human primates have dominant handedness like humans do?"
] | [
false
] | null | [
"Findings on the subject are inconsistent. Some studies have found no evidence of handedness while others have found clear hand preferences. Often individuals favor one hand strongly but the choice seems random. Most likely there is no strong species level lateralization like with humans but rather individual learn... | [
"I know your question was about primates, but I thought this might be of interest. Rats and mice also tend to have a dominant \"hand\" and it tends to be the right one more than chance",
"https://www.sciencedirect.com/science/article/pii/S0166432801003308",
"https://www.sciencedirect.com/science/article/abs/pi... | [
"We haven't noticed any with monkeys, and we've worked with many species. ",
"I have no experience with nonhuman Apes in research."
] |
[
"Is it true that as we get older, our brains will lose it's capacity to learn new skills?"
] | [
false
] | ....Or could it be just due to the lifestle changes as we grow? Job/responsibilities/having no spare time/ etc ... ? Particularly i don't feel i like my capacity is affected on a neurological level, rather it feels like more as if my attention was focused on other things that being the reason for learning impairment on a later age. Anyways, curious about it. Thanks | [
"Age does affect our overall brain plasticity, so basicly how well our brain forms new synapses. You dont lose the capacity to learn new skills as you age, rather it can be more challanging for you to make those special connections which are associated with learning new things.",
"To my understanding, being cogni... | [
"One of the best practical things you can do to encourage lifelong neurogenesis is to learn to play a musical instrument. Larry Sherman (a neuroscientist at OHSU) has a fabulous talk he delivers on the topic, though I'm coming up short on an online reference to it aside from one of the event links where he delivere... | [
"How else does one maintain/improve brain plasticity?"
] |
[
"If humans have evolved to have hair on their head, then why do we get bald? And why does this occur mostly to men, and don't we lose the rest of our hair over time, such as our eyebrows?"
] | [
false
] | null | [
"Edit: My answer below covers the mechanistic reasons for baldness (because I'm biochemist and that's the portion I know about) and why it occurs mostly to men. I'm not aware of definitive research on the evolutionary reasons for baldness so I've stayed away from speculating on that and tried to stick to what bioch... | [
"Mma fighters who a use testosterone replacement therapy such as Dan Henderson, randy couture, or the commentator Joe Rogan all go bald and get big fat heads. They look weirdly similar after they do that. ",
"Why is it? "
] | [
"The patterned baldness I guess might be a result of the ",
" added testosterone. It would be hard to say with a sample of just 3 people.",
"wrt their body and facial structure I don't really know enough about testosterone's other systemic effects to comment."
] |
[
"Do VHS tapes expire or just lose data over time?"
] | [
false
] | My question is a bit more complex, i'm wondering if i store a VHS in a cool dry enviroment over time (decades) would the quality of the movie ever decrease? If I video tape over that old VHS would it be at a good quality again? | [
"The magnetic layer of the tape will eventually come off. When you play an old tape you will find brown dirt on the head which comes from the dissolving tape. The lifetime of a tape is around 10 years.",
"Another effect is that the magnetic information will be copied to the next layer on the reel. Therefore casse... | [
"Try it. Make sure to read the tape only once to minimize mechanical wear."
] | [
"Couldn't agree more. \nDigitise them and store them in at least two locations.",
"I'd recommend at least one be an online service like Glacier or Carbonite. ",
"Also my last manager told me his family lost some home movies on VHS tapes because a mould or fungus grew on the tape itself. I don't know how common ... |
[
"How can nuclear fusion happen in a star when hydrogen doesn't have neutron?"
] | [
false
] | [deleted] | [
"Protons and neutrons can turn into each other by emitting/absorbing electrons/positrons and neutrinos/antineutrinos.",
"In the case of fusion, two hydrogen atoms combine to make a deuteron (which is Hydrogen-2, which is a nucleus with one proton and one neutron), and conserve charge and lepton number by emitting... | [
"For those on mobile, this image might appear as just a bunch of circles with the 2 keys at the bottom. Just open it in a non-night mode browser, it'll actually show everything that way."
] | [
"It might need to be noted that this reaction isn't actually the dominant source of energy in stars slightly larger than our sun, the CNO cycle is",
"http://en.wikipedia.org/wiki/CNO_cycle"
] |
[
"I left a bag of skim milk out by accident. When I found it, the bag was full of air and about to burst. The milk was gunk floating in clear fluid. What happened?"
] | [
false
] | null | [
"When the milk warmed up, some acid and gas producing bacteria had a feast. Some bacteria produced the gas that filled up the bag with 'air' and other bacteria produced some acids that caused the fats and stuff (gunk) in the milk to separate from the whey (clear fluid). The same thing happens when you make ricotta ... | [
"The likeliest culprit here is fermentation carried out by bacteria present in the milk. These bacteria, when breakup(ferment) the milk give off gases. e.g fermentation of a sugar, a glucose, releases carbon dioxide (a gas)."
] | [
"It depends on exactly what bacteria took up residence. How does it smell?"
] |
[
"Everyone says to get a colonoscopy at 50 but what other tests should be mandatory throughout your life?"
] | [
false
] | Something I'm generally curious about. I mean, how many lives could be saved from certain cardiovascular diseases if a Magnetic Resonance Angiogram (MRA) was talked about as often as a colonoscopy? | [
"There's even doubt about some of the obvious screening tests listed about; mainly because of a fifth criteria: 5) early intervention as a result of screening should improve outcomes over intervention that does not come as a result of screening (i.e., if you hadn't been screened, but just waited until symptoms appe... | [
"There are a few screening modalities that have some proven evidence of benefit - i.e. mammographies for breast cancer, colonoscopies/fecal occult blood tests for colorectal cancer, pap smears for cervical cancer, +/- PSAs for prostate cancer and low dose CTs for lung cancer in high risk individuals (depending on w... | [
"This is a good point that I just sort of conflated into my #4 above. A common criticism of studies on these screening modalities is the issue of ",
"lead time bias",
", where screening may lead to earlier diagnosis of disease and thus 'longer' survival post-diagnosis, without actually affecting overall outcom... |
[
"If gravity is the bending of space-time, then how can there be a graviton - a single particle of gravity?"
] | [
false
] | I just don't get that part. The presence of matter causes space-time to warp, and it is this warped space-time which we experience as gravity - at least that's how I've heard it explained many times. If this is the case, then how can there be an exchange particle for gravity? (The graviton, as I understand it). The two things don't add up for me - is it a wave/particle duality thing? Does anyone have a vaguely decent which can help me wrap my head around this? | [
"Consider the electric field around a charged object. When the object accelerates, the electric field changes and information that this changes has occurred propagates outward at the speed of light. This is electromagnetic radiation. If the change in the source of the field is discrete (like an electron changing en... | [
"Particles are an antiquated notion. A flock of particles don't determine the underlying shape of the gravitational field. The gravitational field is a flowing four dimensional surface of waves. ",
"The existence of matter at one point causes ripples to propagate on the surface of the gravitational field and comm... | [
"You are talking about two different ways to understand gravity.",
"According to general relativity, it's spacetime being warped.",
"According to quantum theory, it's an exchange of carrier \"particles\" (although \"particle\" is not entirely appropriate).",
"However, we do not have yet a full understanding o... |
[
"Do creatures with short life span perceive time differently?"
] | [
false
] | [deleted] | [
"I believe there are many studies that seem to insinuate that our perception of time is largely based on memory processing. When asked to try and guess after 60 seconds has passed, younger individuals typically guessed too soon (they felt that time was passing faster than it actually did) and older individuals typ... | [
"We don't know how animals perceive the world. We don't even know which animals feel pain, or how much.",
"EDIT: We are confident that some animals, such as mammals feel pain. But we don't know the answer to this question regarding many other species. "
] | [
"Older people guessed too late. They thought only 60 seconds passed, but it was really 80 seconds. Therefore, 80 seconds must pass for them to feel a minute.",
"Thus, time flies by as one ages."
] |
[
"What comprises speech?"
] | [
false
] | What Comprises Speech? Is it a series of overlapping frequencies? What makes an A sound different from an O? What about glottal stops? | [
"This is a pretty involved question. At the most basic level, speech is just a bunch of sounds. Sounds are of course vibrations, and these are produced in a variety of ways in the vocal tract.",
"First of, we need to understand that spelling isn't the same thing as sounds. It's easy to confuse these, but it can l... | [
"Not really sure what you're asking. Words are comprised of phonemes, a language's basic unit of sound, used to form clusters (words) that export meaning. In short, it's the arrangement of sounds to impart a message to a listener. This subreddit is notorious for poor linguistics answers (*cough* ",
"What's the ol... | [
"I think he means \"what are sounds made of\""
] |
[
"Why do some very expensive CPUs use lots of slow cores vs. fewer very fast cores?"
] | [
false
] | Basically my question as an amateur computer builder and IT curious person with not a ton of in depth knowledge of computer engineering is this: Server grade processors, which have MSRPs that at the highest price point are $20,000+US, seem to utilize tons of cores running in the mid 2.5 GHz range per core. High end enthusiast processors run significantly less in the $500 - $1000 range and have core speeds that are now pushing past the 5 GHz range per core. What are the limitations or engineering reasons why you don't see at this moment, Intel or AMD releasing CPUs with massive core counts and also massive clock speeds? Wouldn't it theoretically be an advantage to have a ton of super fast cores? Are the reasons economic or due to engineering or technological limitation? A more minor follow up would be is this something that the future of CPU design has in store or is it less practical as high core counts and programs meant to utilize multi-core systems become more common and standard? | [
"Speaking for the supercomputers my lab uses, we are actually not terribly interested in the cpu's processing power for many of our calculations - a 5 year old Xeon doesn't matter when you have a Titan V. We get much better performance from gpus so that's where the money ends up going (think the ",
"Nvidia DGX-2... | [
"It's simply different optimization for different tasks. Faster cores require more power, and power is a major limiting factor in CPUs, due to the motherboard supply limits or the cooling fan dissipation limits.",
"",
"Home users with enthusiast processors tend to do things like gaming or light media editing t... | [
"The gpu is so strong because it takes that same scaling to a higher level, right? Only 800mhz or 1000 but something like 200 cores, or logical threads or something like that?"
] |
[
"What would the pressure be like in a body of water in free fall?"
] | [
false
] | I was thinking about the giant free "ponds" in Larry Niven's Integral Trees. On a planet, pressure as a function of depth is fairly straightforward. But if the water is held together only by cohesive forces, how does it change with "depth"? In the book they were free floating and various sized Water is less dense as a solid so pressure causes it to melt, so I'm not thinking there could be a solid core by pressure. I'm wondering, if there was a drop of water 14 miles across (so the center is as far from the surface s the Challenger Deep), what would the pressure be at the center? Could we scuba all the way through? Maybe it would help to imagine a spherical "drop" of water of radius (depth) x, in free fall, with enough of a "balloon" around it to prevent heat loss and evaporation but not add and "squeeze pressure." How would pressure change through the pond? How big would it have to be to noticeably influence itself by gravitational effects? | [
"Free fall is equivalent to being in a region of space without gravity. Let's also assume a vacuum around it such that we can neglect external air pressure etc.",
"There is one force left, namely cohesion. It will attempt to minimize the droplet surface, morphing the it into a spherical shape. The pressure at th... | [
"That's a combined curve I'd like to see graphed. I hear excel calling me now!"
] | [
"The blob of water is just floating in space (probably surrounded by some shell to avoid evaporation)? You would only get some pressure from gravity of the water. With a surface gravity of 4 mm/s",
" we get a pressure difference of 28 kPa or 0.28 Earth's atmospheric pressure between surface and center (equivalent... |
[
"How can two black holes merge instead of orbiting each other endlessly?"
] | [
false
] | I was recently reading about the LIGO experiment and its famous 2016 detection of a gravitational wave signal consistent with the merging of two stellar mass black holes. A truly remarkable observation, but it left me stuck wondering how the orbit of something like two black holes could ever decay. I imagine bodies orbiting in space somewhat like a pendulum oscillating in a perfectly frictionless environment; unless something significant intervenes they would seem inclined to orbit each other nearly perpetually. It seems especially unlikely when you consider there can’t be tidal forces on what are essentially points (or can there?), and when it is difficult to imagine anything with more inertia than a black hole. What is the “friction” that could provide damping of the orbits of two black holes? Does this occur with other orbiting bodies, like planets around a star or are there mechanisms unique to such extreme objects? | [
"What is the “friction” that could provide damping of the orbits of two black holes?",
"Gravitational radiation. They emit gravitational waves, and lose energy. They spiral towards each other and eventually coalesce.",
"It's not unique to black holes; orbiting objects emit gravitational radiation, but the rate ... | [
"E.g. the earth radiates away ~",
"200 Watts",
" through gravitational waves due to its orbit around the sun."
] | [
"Time depends on the location, but that's not relevant here."
] |
[
"So recently I’ve been told that Earth is the only planet in our solar system, where water can be liquid, gas and solid. This is interesting as it is but I was wondering why it isn’t like this on the other planets?"
] | [
false
] | null | [
"The statement isn't quite accurate- it's probably the case that Earth is not the only place where water can be in all three states at once. The rarest state of water in the solar system is definitely liquid water, while gaseous and solid water are probably present everywhere in at least trace quantities. Thus, the... | [
"Thank you for the thorough explanation!!"
] | [
"If we're really limiting the inquiry to planets here, and water in the familiar forms on earth (ice, flowing water, vapor) I think it might be a somewhat overly specific question; our sample size is just to small. ",
"You have eight planets; of them, four don't have solid surfaces at all, which would rule out su... |
[
"Does a Fermionic condensate violate the Pauli exclusion principle?"
] | [
false
] | Does a Fermionic condensate violate the Pauli exclusion principle? | [
"This is from Wikipedia:",
"\"It is far more difficult to produce a fermionic superfluid than a bosonic one, because the Pauli exclusion principle prohibits fermions from occupying the same quantum state. However, there is a well-known mechanism by which a superfluid may be formed from fermions. This is the BCS t... | [
"I'm not sure you're asking so I'll cover the bases:",
"A cooper pair might consist of one electron with momentum +p and another electron with momentum -p, so these electrons do not occupy the same state. However, the coupled pair has a total momentum quantum number of zero (p-p=0). If you have many such pairs,... | [
"But aren't these coupled pairs occupying the same quantum states?"
] |
[
"Lake Baikal growth: how is it measured?"
] | [
false
] | Hi guys, I was watching a video of SciShow about lake Baikal ( ). At the very beginning of the video (min 1:07) they mention that the lake gets wider about 2cm annually. I have no doubt about the tectonic fact, however, I was wondering how can it be measure with such precision. Of course, my first thought was "well... using satellite you can compare one image to the other, yadah yadah", but talking about such large distances, and satellite images, measuring a difference of cm sound like a long shot. Maybe I'm wrong and is possible. Anyway, this is just a curiosity, I would appreciate your answers. Cheers!! | [
"First off, I don't know where they got 2 cm/year, at least if they're actually talking about the lake widening from rifting, because the rate of extension is significantly lower than that at ~4 mm/yr. This measured rate of extension does involve satellites, but not images. It's measured using permanent/continuous ... | [
"Wooooow. Thank you! This is a great explanation. You have not only enlighten me but now I’m super curious about these measurements. Gonna have some interesting reading to do. \nIf only I had coins to award you. But be sure you have my forever appreciation."
] | [
"These are some good options -- thank you!"
] |
[
"What is happening in the brain when someone is unconscious?"
] | [
false
] | null | [
"Unconsciousness is defined as a mental state that involves complete or near-complete lack of responsiveness to people and other environmental stimuli. When you are asleep you are still fairly responsive to your environment. You would respond to noise, movement, your eyelids being opened, and painful stimuli. So, n... | [
"We don't know exactly what is happening but here is the best guess. Anytime someone is unconscious (that is not medically induced) they have either sustained a traumatic head injury or are seizing. We know that the brain stem is usually spared because they are breathing and the heart continues to contract. The e... | [
"Anytime someone is unconscious (that is not medically induced) they have either sustained a traumatic head injury or are seizing",
"Does sleep not count?"
] |
[
"If you melt a magnet, what happens to the magnetism? Does the liquid metal retain the magnetism or does it go away?"
] | [
false
] | null | [
"Sometime before it melts, the ",
"Curie temperature",
" will be exceeded and it'll lose its ability to retain a magnetization in the absence of an external field."
] | [
"I'm an amateur blacksmith, and I've seen people use magnets to check the temperature of steel they're working on. If the magnet doesn't stick, you know it's past the Curie temperature"
] | [
"And ready to be quenched! This is because the crystalline structure inside has realigned. This causes loss of magnetism and is good for strength. That's why we freeze it it by quenching"
] |
[
"Can x, y, and i be graphed on the same graph?"
] | [
false
] | This question came up in my high school Algebra II class today. We were learning about graphing complex numbers using the complex plane, and someone asked if you could just add the imaginary axis to a graph that already has x and y axes. My teacher said he had never really thought about it, and therefore could not provide a good answer. If you can graph all three (x, y, and i) on the same graph, what would it look like? If you can't, why not? | [
"While I prefer teachers to admit when they don't know something rather than dissemble or deflect, I hope this is no indication of the general state of your teacher's education in mathematics.",
"I'm not quite sure what the question is about, but in general, the answer is yes. There are three possibilities:",
"... | [
"Lots of good answers here, but let me try my own shot at explaining things in a way that's very very simple and directed straight at what's useful for the OP.",
"• Right at the outset, it's important to distinguish between x & y, which are variables in this context, and i, which isn't. The simplest way to think ... | [
"I believe that you misunderstood the question. The question is about the graphical representation of a complex number such as Argand diagrams and if there exists a representation in which there are 3 axes. Unless I also misunderstood the question, but if I'm right I don't understand why his teacher did not know th... |
[
"Help resolve a roommate argument. Would plastic blinds that are closed over a large window have any insulative properties?"
] | [
false
] | Two roommates have a two day long argument over whether or not the plastic blinds they have hanging in front of a large window in the living room would help, even if only a little, to keep cold air out. Not saying that the window is open. Any science to end this civil war? | [
"This is exactly what I was looking for, thank you. I can't wait to show this to them and walk around the house with a well-deserved smug look on my face. "
] | [
"This is exactly what I was looking for, thank you. I can't wait to show this to them and walk around the house with a well-deserved smug look on my face. "
] | [
"The blinds help, ",
"I think you're doing some disservice by not including what I assume was roommate's argument -- That the sun through the windows is helping heat things up.",
"During the winter, any windows you have facing the south (Or north if you're in southern-hemisphere winter) should have the blinds ... |
[
"Why is there less oxygen in the atmosphere than is believed to be present in prehistoric times?"
] | [
false
] | As I understand it, in prehistoric times there was a lot more oxygen in the atmosphere, and now we have less. Where did it go? Thanks! | [
"It binds with other elements, limestone CaCO3 traps quite a bit "
] | [
"Photo-autotrophic organisms such as plants and phytoplankton 'sink' carbon dioxide in order to utilize the sun's energy, and have a net release of oxygen.",
"It is thought that these photo-autotrophs were so good at sinking the CO2, that they flourished excessively. They eventually poisoned themselves by releasi... | [
"Originally oxygen was just a waste product, created by cyanobacteria via photosynthesis about 300 million years ago. Oxygen was toxic to most forms of life at the time. As forms of life adapted to use oxygen, we saw a gradual reduction in oxygen levels. The oxygen didn't actually \"go\" anywhere, its just not in t... |
[
"Why don't stretch marks bleed when formed?"
] | [
false
] | So i've got a bunch from both weight lifting and letting myself go for a while there and as they appear, it always surprises me because there is no real signs that it's happening, they just seem to show up all of a sudden. Why is it that if your skin is basically ripping, why do those areas not bleed when it happens and why is there no pain involved? | [
"Not really. You can try cocoa butter to get them to fade, but there is no real cure for stretch marks...if there was a cure, believe me, Oprah would not have them."
] | [
"your skin has three layers. The dermis, the epidermis and the subcutaneous layer. Your blood vessels are in the dermis layer. You can damage part of your skin without damaging the blood vessels (which would cause you to bleed).",
"Your skin can stretch and feel strain. It will compensate by laying down new mater... | [
"Think of your skin as a rubber band that can stretch and stretch and stretch without breaking, however your skin will as a rubber band does when you stretch it get a stretch mark, same thing happens to your skin."
] |
[
"When metal wears down, like a coin wearing smooth over time, where do the atoms/matter go?"
] | [
false
] | [deleted] | [
"All over the place. On your hands, the table, your pocket and other coins, etc."
] | [
"Could be absorbed into your skin (in the coin example) or just becomes part of the dust in the environment. Whether that's outside, in your pocket, or on your floor."
] | [
"So I could have a single molecule of steel just hanging out on my skin?"
] |
[
"What does a spider’s field of view look like?"
] | [
false
] | I’ve seen pictures of spiders having eyes on parts of their heads where it looks as if a fluid and connected image would not be possible. Do they see similar to say, a security set up where there are different points of view? Or does the image present itself like one very wide angled picture? Thanks! | [
"The answer will depend somewhat on which type of spider you're considering. While almost all spiders do have eight eyes, their specific structures and arrangements are ",
"impressively variable",
". Tarantulas, for example, have pretty poor visual acuity overall (and only one type of light-sensitive pigment;... | [
"Spiders on average have roughly a 300 degree field of view.",
"We humans on the other hand have 120 degrees of field of view.",
"So basically a spider can see its front , sides and ,in its peripheral view, some of its rear"
] | [
"If imagine it’s probably stitched together just like our vision is, but we can’t really tell. It’s not like we can just ask spiders what they see. We would need to completely reverse engineer their nervous system to find out."
] |
[
"Why do guns kill people so quickly (or are movies lying to me?)"
] | [
false
] | [deleted] | [
"Movies are lying to you. As you suspected, gunshot wounds are very rarely instantly fatal. A shot to the abdomen or chest is often not even incapacitating for some time. ",
"Anecdotal, but relevant: my grandfather was shot through the throat by a high powered military rifle round, and wasn't at all sure what... | [
"First question: does getting shot kill you as quickly as it does in the movies?",
"I don't think that most of the time movies are lying to you. They are just simplifying things for you to help the flow of the movie. In reality a lot of the people shot would probably be writhing in agony and slowly dying and so o... | [
"99% of military rounds are FMJ they are designed to pass through. hunting rounds are soft and designed to deliver their energy into the target. that is why when cleaning a game animal you find the heart/lungs have been obliterated, and a massive exit wound.",
"watch this ",
"video",
" he starts shooting at a... |
[
"If I'm 21 with a receding hairline, what are the chances that I'm not going to go entirely bald?"
] | [
false
] | I realise this is a desperate and ultimately futile question, but one can dream..... | [
"you have no idea how reassuring that is"
] | [
"my hairline started receding about that time, the progress stopped a couple years later and now i'm 39 years old with the same head of hair, quite full, albeit a couple inches higher up."
] | [
"I think it goes by your maternal grandfather, at least mine does."
] |
[
"I know 0 Kelvin is the lowest temperature achievable in the universe. Is there a maximum on the other side of the scale? If so, is it possible for scientists to reach it?"
] | [
false
] | We are learning about low temperatures in science class and I was wondering how things were at the other side of the spectrum. Is there a Bose-Einstein condensate type effect that happens at high temperatures? Also, I'm in 8th grade so simple terminology would be appreciated. | [
"Scientists actually aren't sure if there is a maximum temperature or not. A good theoretical bound is Plank's Temperature but that is only because current models break down above that temperature. Within other theories there are other maximum temperatures by different mechanisms."
] | [
"Just for kicks, I will point out that technically, there is such a thing as a negative temperature on the Kelvin scale. Although these are generally odd states that can be created under very strict circumstances."
] | [
"No, its not that if has negative energy. Its that it gains entropy by losing energy. (Typically object lose entropy as they lise energy). So if this negative temp object transfers energy to a normal object, both gain entropy. The net entropy increasing means the process happe.s "
] |
[
"Why must chocolate be tempered?"
] | [
false
] | I've seen it done on cooking shows and how-they-do-it type things before but I'm not entirely sure why it's done. | [
"Cocoa butter can form at least 6 different crystal structures. Only one - the so called beta form - is what you want. The different crystal forms have different temperatures at which they melt, in addition to the other properties (shine, snap...)",
"The trick in tempering is to get a liquid substance with enou... | [
"There are three ways to do it, and one of them is melting and remelting. In that way you heat the chocolate up to 120 deg or so. This melts all of the crystals of every form. Then you cool it quickly down to 82-85 deg while working the chocolate in a bowl or on a slab. This forms a whole lot of very small beta... | [
"I can personally attest to this man's chocolate tempering skills. I had no idea how involved it was."
] |
[
"This may be a dumb question, but would it be possible to change what “type” of cell a cell is?"
] | [
false
] | So I’m currently taking highschool biology, and we’re covering cells. The notes mentioned that cells such as blood cells, muscle cells, and nerve cells have the same DNA, they just have different genes activated by chemical signals. Assuming that this is correct, could purposefully giving the cells a certain chemical signal to make them into a different cell work? As an example of what I mean, perhaps sending chemical signals to a stem cell to create new nerve cells to repair nervous system damage. And if it is possible, why aren’t we currently doing it? | [
"Yes, there are many examples already:",
"https://scitechdaily.com/neurons-can-be-changed-from-one-type-into-another-from-within-the-brain/",
"http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/moaction/change.html",
"https://www.sciencealert.com/scientists-discover-an-enzyme-that-can-change-a-person-s-b... | [
"One of the strategies for stem cell research involves taking differentiated cells (eg skin cells) and turning them into stem cells with chemical signals. These stem cells can then be differentiated into other target cells. ",
"In such a system one would collect your cells, produce stem cells, then populate a str... | [
"Like everyone else said, it is possible, but there are limits.",
"Red blood cells, for instance, can't be changed because their DNA is destroyed as a part of the process of becoming blood cells.",
"If a cell is highly specialized, it may have already implemented changes which would be hard to reverse. A nerve... |
[
"Layman proof of an old earth"
] | [
false
] | null | [
"There's not really any such thing, no. That's a big part of why young-earth creationism is so popular; if you're willing to believe that every scientist in the field is lying, you won't run across any reason to change your mind. If you try to deny relativity or something, you still have to explain why all the scie... | [
"If there were, we wouldn't have had to wait until after several thousand years of human history to figure it out; the old Earth would have been in Plato and Aristotle and that would be that.",
"Also, there's no such thing as \"proof\" in science - all we can do is gather more and more evidence for or against som... | [
"How about the fact that it is very unlikely for such a complexity to develop from an evolutionary system in a lot less time? Oh, wait..."
] |
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