title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Energy transferred and effects of a satellite based rail gun"
] | [
false
] | null | [
"The idea was briefly explored in the past, you can read about the details of the project here:",
"\n",
"http://en.wikipedia.org/wiki/Kinetic_bombardment#Project_Thor"
] | [
"Indeed, overall it doesn't give too many substantial benefits over conventional bombs at those speeds. There is another variation on kinetic weapons which involves accelerating them to appreciable fractions of the speed of light. Those are virtually impossible to defend against and devastating on a planetary scale... | [
"I knew some other maniac had to have thought of that already. I was pretty much spot on with my approximation of 3000m/s, mach 10 is about 3500m/s, but they went with 9 tons which is WAY more than my 2 tons. "
] |
[
"I wish to get into DIY Biology as a hobby. More inside."
] | [
false
] | null | [
"What area do you want to work in? You could contribute to ecology with minimal funds but you will always run the risk of not being taken seriously without a university affiliation. You will also find that material and service prices are higher for non-academic research. Outside of ecology it would be really diffic... | [
"Have you seen what ",
"OpenPCR",
" is doing? That could be a decent start. ",
"Next-gen sequencing is producing a lot of data that needs to be analyzed, so you may also want to consider some of the computational problems in the field. Getting experience in bioinformatics could pay off when you start shopping... | [
"Have you seen what ",
"OpenPCR",
" is doing? That could be a decent start. ",
"Next-gen sequencing is producing a lot of data that needs to be analyzed, so you may also want to consider some of the computational problems in the field. Getting experience in bioinformatics could pay off when you start shopping... |
[
"What does it mean for something to behave as a wave?"
] | [
false
] | What does the wave part of something represent physically? Like how could I visualize what the wave function determines? | [
"If something behaves as a wave, it means that the certain something obeys the ",
"wave equation",
".",
"Let the certain something be a quantity we call X. When someone says that X is a wave, it means that if you were to : ",
"set up an array of detectors at different positions, and activate them all at the... | [
"So what does it mean when everything has a wave property but it's small? Like how can humans obey the wave equation?"
] | [
"That's the problem/brilliance of quantum physics, it describes phenomena at a greater precision than we're capable of perceiving, and those phenomena at that precision aren't analogous to the phenomena we are capable of perceiving. We can construct weak analogies to try to give laymen an idea of what's happening, ... |
[
"Which of the four fundamental forces determine concentration gradient movements?"
] | [
false
] | There's osmotic pressure if there is a different concentration of some solute on one side of a compartment than another. Ultimately , what fundamental force is determining the strength of the pressure? | [
"I wouldn't say it's any of the forces that give rise to any chemiosmotic potential, as it arises from statistics (i.e., driven by entropy).",
"Let's examine another case of entropy at work. There are only so many ways that a deck of card can be ordered sequentially. What is the \"force\" that causes a brand new ... | [
"The rate at which water moves from one side to another is dependent upon the concentration of water. It is also dependent upon hydrostatic pressure. At equilibrium those two are balanced. Statistics is what drives the former, gravity the latter."
] | [
"As far as chemistry, biology and every other natural science is concerned, you only need to take electromagnetism into consideration, once you have accepted that",
"most atom cores are stable, some are radioactive",
"the sun produces electromagnetic waves",
"everything is pulled to the earth's core due to gr... |
[
"If photons have no mass, what is actually bouncing off of things (reflecting)?"
] | [
false
] | Why wouldn't light just pass through everything? Am I confusing matter with mass? Do photons contain matter? | [
"\"Bouncing off things\" does not really exist at the fundamental level, even for marbles. The human-scale effect of objects touching, colliding, and recoiling is an inexact description of the underlying physics that seems good enough to our limited human senses. Objects can really only interact via the fundamental... | [
"Thank you."
] | [
"This can happen, but it's different than reflection. In fact there are many ways light can interact with matter. What you're talking about is called fluorescence (",
"http://en.wikipedia.org/wiki/Fluorescence",
").",
"There are also processes called scattering (",
"http://en.wikipedia.org/wiki/Scattering",... |
[
"If a person were to take an opioid antagonist for a long period of time and then stop, would they go through \"anti-withdrawal,\" a withdrawal that felt good?"
] | [
false
] | null | [
"I don't think so. There is a difference between sudden removal of opiods from the system (as in withdrawal) and blocking the binding of an opiod to its receptor. "
] | [
"No, they would not. Opioid antagonists simply block the binding of an opioid to opioid receptors. Removing the antagonist allows opioids to bind again. But if there is no significant amount of opioids circulating in the blood, then no opioids would bind, so these receptors would still not be activated and you w... | [
"There -are- opioids in your brain. That's what gets evicted when you take, for example, Narcan. That's what flows back when the Narcan goes away. I've experienced something similar to this before. If you were to take Narcan longterm, you would feel wonderful once it vacated the opioid receptors. Not like shooting ... |
[
"Does your body build a tolerance to alcohol or does a person simply get used to being inebriated?"
] | [
false
] | Is it a mental or physical factor? I guess what I'm asking is if there are chemical differences in your body from being a regular drinker than some one who doesn't normally drink and gets drunk with three beers? Why can a regular drinker consume more than a non drinker? Or is it just a matter of "I've been in drunk sta... | [
"Both. Here's some evidence. ",
"\"Tolerance that results from a more rapid elimination of alcohol from the body is called metabolic tolerance (2). It is associated with a specific group of liver enzymes that metabolize alcohol and that are activated after chronic drinking (21,22). Enzyme activation increases alc... | [
"lexerlol covered the metabolic changes well, but I can expand on the Central Nervous System's adaptation to alcohol. The receptors currently thought to be most effected by alcohol in the brain are the GABA_A receptors. With chronic use (and even with a high dose single use) neurons that express these receptors beg... | [
"Alcohol consumption interferes with many bodily functions and affects behavior. However, after chronic alcohol consumption, the drinker often develops tolerance to at least some of alcohol's effects. Tolerance means that after continued drinking, consumption of a constant amount of alcohol produces a lesser effect... |
[
"Are there any vocal sounds humans do not use linguistically?"
] | [
false
] | I nguess the implicit first question is do we have a decent catalog of the sounds that humans make. Assuming the answer is yes, are there any at all, or any particularly interesting examples of sounds that go unused? EDIT: Sorry, yes, it's clear that there are a large number of exotic sounds we can make, perhaps unboun... | [
"The answer to your question is: yes, there are vocal sounds that humans do not use linguistically, and no, there isn't a decent catalog of the sounds that humans can make.",
"To explain this answer I think that we need to clarify the question a little. What counts as a \"sound\"? What makes two sounds different ... | [
"In regards to your follow-up question: I think the answer is \"no,\" but I think it would depend on what you consider to be surprising.",
"I can think of three scenarios that can cause to be rare: ",
"1) Language families that have it are underrepresented in the sample. There are a lot of surviving Indo-Europe... | [
"One problem with this visualization is that we ",
", in fact, utilize the space of possible sounds this way. ",
"Different languages have both different ",
" - that is, they make use of differing numbers and types of categories for their speech sounds. They also have different ",
" - that is, there are sou... |
[
"Is it possible for gas giants to have a solid core?"
] | [
false
] | Perhaps they are like Mars except with a massive opaque atmosphere? | [
"The gas planets are thought to have rocky cores with Jupiter's having a mass between 10 to 50 earth masses, though I've heard speculation that Jupiter's core has dissolved into the metallic hydrogen that surrounds it."
] | [
"Weve done experiments in a lab to simulate jupiters pressure and we put l arge amount of pressure on hydrogen so much that the hydrogen formed a metallic structure and thats what we think is at the core of jupiter"
] | [
"They probably do. Or at least, most of them probably do. We now have a large population of gas giants when we look at all the other planets we know about around other stars. By looking at temperature and density, we can try to figure out what their interiors are like, and it looks as though they'd all have some so... |
[
"For every watt of electricity you use inside an air-conditioned building, how many watts of electricity does your air conditioning consume to remove the heat?"
] | [
false
] | Technically "for every joule..." would probably be better, but watt makes more sense. What factors are there to consider? | [
"It varies depending on a lot of things. A little background first:",
"Air conditioners are rated based on 'coefficient of performance,' which is the ratio of energy moved to energy consumed. For example, an air conditioner operating in certain conditions might expel 4 watts of heat and consume 1 watt of electr... | [
"http://en.wikipedia.org/wiki/Coefficient_of_performance",
"The coefficient of performance or COP (sometimes CP) of a heat pump is the ratio of the heating or cooling provided over the electrical energy consumed.",
"The value of the COP may be between 2 to 3.5 for an AC unit, possibly an even larger range. It'... | [
"I think it is the other way around. 1 joule expended removes 2-3.5J from the room."
] |
[
"What causes manual breathing? (Sorry, everyone)"
] | [
false
] | null | [
"Many of our body parts can be controlled by our autonomic (automatic) nervous system, and this can be overridden to some degree by our higher brain. You don't ",
" the automatic control, as you can see if you try to hold your breath forever. ",
"When the conscious brain disengages, the autonomic system gracefu... | [
"Breathing is not simply controlled by the autonomic(sympathetic/parasympathetic) nervous system. The diaphragm is innervated by the phrenic nerve, part of the somatic nervous system. The medulla oblongotta and the pons of the brain control automatic breathing. "
] | [
"That's how people drown. Water fills your lungs."
] |
[
"Why do we not have lightning farms?"
] | [
false
] | I live close to and see storms like this frequently. Seems like the towers could be doing a bigger job. What's missing from my utopian lightning farm plan? | [
"Lightning contains ",
"a large amount of energy",
" (around 5 Gigajoules per bolt), but not as much as you would think. With ",
"20 million lightning strikes over the US per year",
", that's 10",
" Joules per year striking the United States. However, ",
"the US uses about 10",
" Joules of energy per ... | [
"Not only does it not producing significant power",
"It produces enormous power, but little energy. Both of those are a problem. ",
"Because of the high power, you'd need a battery that could charge absurdly fast to do anything with it.",
"Because of the relatively low energy content, there's very little pa... | [
"Yes and no. It's true that the average power is low. However... whatever system you build to collect it must be able to handle the instantaneous power-- which is gigantic, and is going to melt all your wires and batteries if they're sized to handle the average power during charging.",
"Imagine charging your ce... |
[
"What is the difference between animals that are made of colonies of smaller organisms and animals that are not?"
] | [
false
] | Aren't all animals made of smaller living cells? | [
"I believe OP is referencing the man-o-war type creature that reached the front page.\nWhat is crazy about these colonies is that they function as a single organism. As a colony, these creatures aren't overly different from a complex animal that has its own tissues and organs, with each animal acting like a tissue ... | [
"Some \"pieces\" of the colony reproduce sexually, while others reproduce asexually.",
"The phenomenon of polymorphism is essentially one of division of labour in which specific functions are assigned to different individuals. Thus, polyps are modified for feeding, protection and asexual reproduction, while medus... | [
"How do they reproduce? "
] |
[
"Why do we become \"blind\" to certain odors in our homes and cars?"
] | [
false
] | null | [
"I think that the brain operates on deltas. Over time, things normalize the input to your brain, so it doesn't react to it any longer. I think this is true for pretty much everything our brain has to process. Like it detects changes based on history, and after a while the history isn't that different from your curr... | [
"I think that the brain operates on deltas. Over time, things normalize the input to your brain, so it doesn't react to it any longer. I think this is true for pretty much everything our brain has to process. Like it detects changes based on history, and after a while the history isn't that different from your curr... | [
"Yep - you're pretty dang close. Scent eliciting molecules have to bind receptors on your olfactory nerves. Different combinations of receptors =different scent stimuli. Those nerves only have so many receptors - when completely bound (with sulfur dioxide, which elicits a rotten egg smell, for example), the stimu... |
[
"How many generations does it take to start seeing an evolutuonary change?"
] | [
false
] | If humans were to isolate and control the environments an animal would live in, how fast would we see a change? For example, if you take 500 mice and keep them in 10 different cages (50 a piece) with controlled environment's like cold weather only, hot weather only, grassy area, forested area and so on. Would we start ... | [
"The best answer is, it depends.",
"Significant changes have been observed in as few as 30 generations per ",
"http://news.nationalgeographic.com/news/2008/04/080421-lizard-evolution_2.html",
" wherein a primarily insect eating lizard species was introduced to an island with a greater abundance of plant matte... | [
"There isn't a set amount of generations, and I would say it would be difficult to even give you a range because there are so many variables in play. For instance, what do you define as \"evolution\"? Technically, a single mutation can be evolution, which can occur after one generation. Furthermore, not all genes/p... | [
"As others have noted, evolutionary changes can happen fairly quickly. This is something that doesn't seem to have trickled down well to the intro evolution courses, since you still often hear people explaining how evolution takes millions of years. Sometimes it does, but not always. ",
"I think that the bigges... |
[
"How are old films able to be re-released in 4k?"
] | [
false
] | All I know about the production of movies is recording it on a camera in a digital format. Does chemical "film" store images at an undefined resolution, which has its presentation limited only by the current projection or screen technology? Has the actual capture quality of the images themselves not improved at all ove... | [
"Film has a ”resolution” imposed by the size of the individual light-sensitive silver halide grains that function as fundamental picture elements. The grains, being just particles suspended in emulsion, are not uniformly sized or neatly arranged into rows and colums like digital pixels, but they are close enough fo... | [
"To add to this Experts say that 35mm is approx. 4000W pixels with an aspect of 2:40-1, which gives 1666H- where 4k is 3840H x 2160H or 1600H if watch in ultrawide format as is typical so overall similar. The issue is most films are only upscaled to 2K due to limitations of projectors in theaters - Experts say i... | [
"bought in 1999 for Avatar.",
"You mean 2009?"
] |
[
"I've heard that there is gold in our bodies. Is that true, and if so, how do we get it and why do we need it?"
] | [
false
] | null | [
"Important \"trace\" or minor dietary elements, necessary for mammalian life, include iron, cobalt, copper, zinc, molybdenum, iodine, and selenium.",
"http://en.wikipedia.org/wiki/Dietary_element",
"There are no known essential functions of gold in the human or other mammalian bodies as I am aware.",
"The mic... | [
"2.3e-3 would mean 2.3x10",
" it's a shorter way to write scientific notation"
] | [
"Well, considering the average human to weigh 70 kg, and if 140e-9 % of that is gold, then one human has 9.8e-8 kg of gold. ",
"Multiply that by the ",
"population of the world",
", 7.213518728 billion, ",
"7 213 518 728 * 9.8e-8 = ",
" "
] |
[
"Why do endothermic reactions happen?"
] | [
false
] | null | [
"Because they can, assuming you put in enough energy."
] | [
"Because they can. They have enough energy to do so. Since no conservation law prevents it, it ",
" happen some fraction of the time."
] | [
"But why would a pair of reactants choose to settle at a higher energy level?"
] |
[
"Could a human live comfortably on IV nutrients?"
] | [
false
] | null | [
"Pharmacist here. You're talking about parenteral nutrition (",
"http://en.wikipedia.org/wiki/Parenteral_nutrition",
"). Lots of patients at hospitals with serious GI resections etc. require it to get enough nutrition. Some people have to go home on it, though as has already been mentioned, this is not ideal. I... | [
"I'm a first-year med student, and something that was highly emphasized during gastrointestinal (GI) was PO nutrition (eating) was medically preferred over parenteral (IV). One of the biggest problems is that not all amino acids or essential fats are in any one solution, and to top if off, most patients have multip... | [
"No. If it was possible, we wouldn't still have ",
"feeding tubes",
" around."
] |
[
"Why do animals \"play\"?"
] | [
false
] | made me think. Clearly the natural instinct of an animal to an attack is either counter attack or run, what is stopping that dog from being aggressive? How come it does not "misunderstand" the cats sentiments of playing? What are the origins of such a behavior? I think I saw/read somewhere that "playing" is a way by wh... | [
"Playing is the way a child practices important skills it will need in the future. This does vary between species. As you said, for carnivores learning how to hunt is an important part.",
"One of the things with the domestic dog, we have bred them to essentially be puppies their entire life (behavior wise). "
] | [
"In addition, playing also allows them to learn social manners from the elder and establish a pecking order (and establish themselves within that pecking order) among their peers. ",
"Oh and the obvious reason: because it's fun. Even animals get bored. "
] | [
"Oh yah, definitely. What most people call an 'alpha roll' in wolf packs is nothing of the sort. It's the inferior animal willfully rolling itself over to show subversiveness. The alpha animal does nothing until challenged. "
] |
[
"what’s the ‘effect’ when something is moving so fast it appears to be static?"
] | [
false
] | null | [
"Like this: ",
"https://en.m.wikipedia.org/wiki/Wagon-wheel_effect",
"?"
] | [
"yeah you know what, maybe it was the stroboscopic effect but i was just complicating things"
] | [
"Laminar Flow! i know it’s random at this point, but something came up on the feed which perfectly demonstrated what a sought. i found the puzzle piece"
] |
[
"Does the total amount of solar energy reaching earth change with orbital eccentricity?"
] | [
false
] | I'm thinking about Milankovitch cycles and my understanding is that its effects on Earth's climate and glaciation is not due to changes in total solar energy, but due to the distribution of that energy throughout the seasons. My question is theoretical: does the total solar energy reaching earth remain constant at all ... | [
"If you're holding the semi-major axis (a) constant (i.e. constant orbital period), then the time-averaged heating rate is proportional to ",
". The more eccentric orbit, with the same period, will have a larger integrated irradiance.",
"The Kepler problem for an elliptic orbit is messy, but you can write a clo... | [
"Wow, this is great. Thank you for your effort."
] | [
"So it spends a longer time further away, but in the short time that it is close it is getting a lot more [watts/m",
" The amount of irradiance is proportional to the distance, just as the velocity is, so couldn't they in theory cancel out to give you the same net solar energy throughout one year?",
"I can vagu... |
[
"Are Reptiles A Monophyletic Grouping?"
] | [
false
] | I want to know about the current scientific consensus in regards to Reptiles as being an Monophyletic grouping or class. I mean, is the Reptile class considered to be as a Monophyletic grouping or clade by most scientists or paleontologists, or is it still regarded as a Paraphyletic group considering that the Paraphyle... | [
"Reptiles are monophyletic if birds are included, but in my experience people use this word to refer to either the monophyletic or paraphyletic groupings interchangeably depending on context. Sauropsida is a more unambiguously monophyletic term for essentially the same set of organisms (including birds). Or if yo... | [
"The term \"mammal-like reptiles\" has definitely fallen out of technical usage in the past few decades, since it's not really accurate. Sauropsida is the sister group to Synapsida, so under this view mammals have no ancestors that can be considered reptiles at all, just non-mammalian synapsids (and then earlier a... | [
"With respect to currently living things, yes Amphibia and Amniota are sister groups (but there are also some additional extinct things in there too). The rest of your question kind of hinges on some quirks of casual vs. technical language. For example, stem-tetrapods can accurately be described as amphibious (i.... |
[
"Why are Snow Flakes symmetrical (more or less)?"
] | [
false
] | While arms might be incomplete, etc, why do they form in the same pattern in arm to arm? (even though individual flakes have different patterns from flake to flake) (Edit for clarity) | [
"I'm sure what he means is, how can the branches of a single flake all be symmetrical? How do they \"know\" what the branches on the other side of the flake are doing?"
] | [
"From your source:",
"The second question (How can ice crystallizing on one arm 'know' the shape of the other arms on the flake?) has to do with the way in which snowflakes are formed. The growth of snowflakes (or of any substance changing from a liquid to a solid state) is known as crystallization. During this p... | [
"My intuition is that the air in which a snowflake forms is homogeneous on the sub-centimeter scale. ",
"In other words, all the arms of a snowflake has the same sort of air around it. Each arm forms at the same temperature and humidity as the other arms. That's why all arms are the same on a single snowflake.... |
[
"Is lithotripsy still being used in the USA (or any other 1st world countries) as treatment for kidney stones?"
] | [
false
] | [deleted] | [
"Yes it is still used."
] | [
"I can confirm this.",
"It is used very commonly as it is technically non-invasive."
] | [
"That wasn't your question.",
"There may be a risk associated. I am not an expert in extracorporeal shock wave lithotripsy.",
"One thing I do have confidence in is the power of malpractice lawyers in the US. It's unlikely that it is causing a huge amount of diabetes (or other problems) or else the lawyers wou... |
[
"Is there any difference between the weightlessness experienced while in orbit and in the middle of space?"
] | [
false
] | null | [
"Not really, for all practical purposes. Nothing that you could sense, if that's what you mean.",
"There's a tiny difference in the gravity exerted on your feet versus the top of your head when you float in the station with your feet pointed toward the Earth, but it's imperceptible - and that difference would be ... | [
"Just to clarify, this effect is even less perceptible in orbit than on the surface of the earth. And we don't even notice it on the ground."
] | [
"Yes, we have gravimeters that are sensitive enough for that. ",
"Additionally, one mechanism for keeping satellites oriented is ",
"tidal stability",
", which involves a satellite extending a mass along a long axis; that mass combines with tidal forces to exert a small torque to keep the satellite oriented.... |
[
"How does one handle or manipulate a single atom?"
] | [
false
] | I was reading the article about a single photon altering another single photon, and they mention adding a single atom of an element into the experiment. How do they handle, or manipulate single atoms? How are elements broken down to the base atomic level? For that matter, how are they able to create two single photo... | [
"We can use ",
"atomic force microscopes",
" and ",
"scanning tunneling microscopes",
" to manipulate them, as IBM did with ",
"A Boy and His Atom.",
"We can also use ",
"magnetic",
" and ",
"optical",
" tweezers to trap and move atoms around. Other ways that can work with a few atoms and large... | [
"In A boy and his atom, what are the things that look like waves which propagate away from the atoms?"
] | [
"The atoms making up the surface are just further away from the STM probe than the ones sitting on top of it. Scanning tunneling microscopes are ",
" sensitive to distance, so holding the probe at the right height lets you see the carbon monoxide atoms but not the atoms below them (the substrate was apparently c... |
[
"Has there been any carnivores that evolved into herbivores, and vice versa? Plus how would it be possible?"
] | [
false
] | Probably a stupid question | [
"In 1971 scientists moved 5 pairs of insectivorous Italian wall lizards to the tiny island of Pod Mrcaru [sic] off the Croatian coast. War broke out, so the scientists left. They returned in 2008 to find that the native lizards were gone and the 5,000 descendants of the transplanted lizards were now herbivores, hav... | [
"Giant pandas!",
"Early herbivorous amniotes (Caseidae, Captorhinidae, Diadectes) evolved from ancestral carnivorous and insectivorous amphibians.",
"Herbivorous bees evolved from carnivorous wasps (who evolved from herbivorous ancestors, ",
"All herbivorous fish evolved from their respective carnivorous ance... | [
"\"Tail clips taken for DNA analysis confirmed that the Pod Mrcaru lizards were genetically identical to the source population on Pod Kopiste.\" ",
"Source",
"Another source from NatGeo confirmed this as well but it was behind a paywall."
] |
[
"Do THC Breathalyzers exist?"
] | [
false
] | [deleted] | [
"THC does not evaporate from your blood through lungs into your breath like alcohol. It cannot be detected in breath. It is detectable from saliva though and ",
"here",
" is a concept of a handheld gadget for that."
] | [
"As they should. I'm perfectly OK with them testing me if they think there is some reason to do it."
] | [
"I'm hopping on your question to ask this: I read about a new proposed law that would consider 5 nanograms/ml the limit on THC blood concentration for drivers. Is it even possible to accurate detect 5 nanograms in a ml of blood?"
] |
[
"What happens to the other gases such as nitrogen in the air that we breath in?"
] | [
false
] | null | [
"Mostly nothing. A little bit of it might enter into our blood stream as a dissolved gas. This might be consequential if you happen to be a deep sea diver under some circumstances. But nitrogen gas doesn't really participate meaningfully in much biological processes in our body."
] | [
"A little bit of it might enter into our blood stream as a dissolved gas.",
"And a little bit goes from the blood to the air in the lungs. Same for argon."
] | [
"They’re dissolved in the blood but don’t carry out any particular function; just excreted again when you exhale. Exceptions are things like carbon monoxide, which binds to haemoglobin instead of oxygen, which is why it’s so dangerous.",
"Might seem weird that places manufactured to have oxygen in the air, such a... |
[
"How can there be a smallest component of matter?"
] | [
false
] | Wouldn't everything have to keep being made up of smaller and smaller somethings? For example, I know a quark is an elementary particle, but doesn't something have to make it up? And then something would make those somethings up. And each something would be smaller than before. Or something like that. | [
"This is only the case if you try to think of particles as little balls of stuff floating around in space. In reality, elementary particles are actually fields that permeate all of space, and it is localized excitations of these fields that creates the particles we are familiar with. "
] | [
"No, why? You can very well stop at some level, and have some truly fundamental thing, that doesn't itself isn't made of anything smaller. For example, a true point particle, i.e. a particle with no extent in space; this can by definition not get smaller or consist of anything! This is how we think of fundamental p... | [
"I know this is a little late t the party, but what are these fields composed of? What \"are\" they? And what is the excitation that calls these particles into being?"
] |
[
"What tells one cell to do or become one thing while another cell does or becomes something else?"
] | [
false
] | null | [
"You may be confusing the word ",
"morphogen",
" with ",
"mutagen",
". The former are proteins (often master transcription factors) that are non-uniformly distributed in developing embryos; morphogen concentration gradients provide spatial information to differentiating cells to initiate patterning programs... | [
"During early development cells are described as being pluripotent or totipotent. These classifications suggest a cell is a stem cell and can potentially undergo a variety of fates to ultimately become the cell type it is going to be. ",
"The determinants are the stage of the stem cell - a totipotent cell such as... | [
"This is a massive question that you could fill an entire university semester with. So if it's interesting to you, there's a lot to read and learn about. The short answer is that chemicals called cytokines are produced for a variety of reasons, and these drive progenitor cells (like stem cells) to become one thing ... |
[
"A question about cortisol and glucocorticoids."
] | [
false
] | I work with stress management training and do a lot of education of the physical effects of stress. I have a couple of things that I grasp at a basic level but I want to understand more clearly and double check what I am teaching is accurate. First, what are the physical effects of cortisol and glucocorticoids on the b... | [
"I really can't answer all those questions, but here is what I can say:",
"Increased cortisol levels are associated with increased incidence of Alzheimer's disease, owing largely to an imbalanced HPA axis (hypothalamic-pituitary-adrenal axis). ",
"Here",
" is a google scholar search on that topic.",
"Glucoc... | [
"Thanks a lot for your help. I am not very skilled at navigating Google Scholar so I can never seem to find articles that are relevant to my question. Normally I utilize ",
"r/scholar",
" to find great articles on subjects, but since I had such a range of different questions I figured this would be a good place... | [
"Pharmacist here, so I guess I am somewhat qualified to answer this question.",
"1.) Cortisol and glucocortocoids have a lot of effects on the body, probably more than we even know. Many of them are related to metabolism, fluid retention, and inflammatory mediation. Mentally, they tend to make people have incre... |
[
"Do river and lake fish like trout do schooling? Or is this phenomenon exclusive to oceanic species?"
] | [
false
] | null | [
"Fisherman here- sunfish school, bass school, trout school, carp school, perch school, walleye school"
] | [
"I know layman comment are frowned upon but I think it's fair to state I have seen many schools of freshwater fish in lakes and ponds."
] | [
"Muffin Cakes to Sugar Butt. Muffin Cakes to Sugar Butt. Come in Sugar Butt. I would like to pick up my cell phone. Please tell me when I can come pick it up. Over and out. "
] |
[
"Is our universe a closed system?"
] | [
false
] | This is the kind of thing that as I sit on the toilet, pondering how we came to be. If it is, it must have no begining as matter cannot be created nor distroyed. If it is, it must have some overlap with other universes that have an impact on it. | [
"You can't define the thermodynamic type of the universe as you can't define neither its region, boundaries, surroundings nor thermodynamic parameters such as total energy. ",
"There is no external reference frame to determine the region of the universe, there is no thermodynamically defnable boundaries between t... | [
"Finding an answer that follows the laws of thermodynamics is where I have a difficult time grasping how the universe could have began. (I work in sales so I'm the definition of a layperson)",
"Space-time",
" is the coordinate system we usually use when describing the universe. It combines the three spacial dim... | [
"yet we interact with them through Hawking radiation.",
"How do we interact with something when they aren't part of our observable universe? (Actually, what do you mean by 'observable' ?)"
] |
[
"I'm reading about the electrical system of a dual engine aircraft. It says that the maximum load for single generator operation is 400 amps up until 32,500 feet. Then the max is 280 (the max load with dual generators working). Why does altitude matter in the electrical system?"
] | [
false
] | This is in an engine out scenario with only one operating generator. | [
"The engine produces less power at a higher altitude, because of the lower density. The effect is less pronounced on the apparent propulsion performance because the drag on the aircraft also drops with density (or altitude)."
] | [
"In areas of high altitude, air pressure drops reducing the air density. This can create problems with generator start up if not accounted for since air is crucial for ignition in any type of generator. Another factor that gets affected is availability of ambient air to facilitate heat dissipation from the generato... | [
"Also, it's heat dissipation in the generator and even the wiring, in addition to the engine. Most of the work of the engine is going into propulsion anyway."
] |
[
"Made a sun viewer with binoculars. I know my image is flipped and flopped, but after correction, why doesn't it look like SOHO's latest daily sunspot picture?"
] | [
false
] | After I set up the sun viewer I did an experiment with a desk lamp and come colored post-it notes. Looking at the lamp, an orange post-it note was on the top left, and a green one on the top right. Looking at the project image from the binoculars, orange was on the bottom right and green on the top left, meaning the wa... | [
"SOHO is in a completely different orbit than Earth is in, about a million miles closer to the sun. You are exactly correct, the angle you see it from is different than the angle SOHO is looking at it",
"Nice gifs here",
"http://sohowww.nascom.nasa.gov/about/orbit.html",
"http://sohowww.nascom.nasa.gov/explo... | [
"the sun is 93 million miles from Earth.",
"You are standing on Earth where the angle you view the sun from depends on which way is locally \"down\"",
"SOHO out in space is oriented however it is oriented so it will have a different angle corresponding to the \"top' of the sun",
"for us the top of the sun is ... | [
"Ah, I kept thinking that SOHO was on the same equatorial plane as the Earth, but I see clearly that it is not, especially in looking at its view of the recent Venus transit. From SOHO's ",
"view",
" , Venus didn't even pass in front of the Sun but above it! "
] |
[
"Photons cause electron decay/excitation between states, provided its energy is 'exactly' the difference between to the two states in question, but how 'exact' is 'exact'?"
] | [
false
] | null | [
"The energy doesn’t need to be exact. States with finite lifetimes also have nonzero intrinsic energy widths. The energy width is inversely proportional to the lifetime of the state.",
"Then there can be additional line broadening effects, for example due to Doppler shift at nonzero temperature."
] | [
"ah of course that makes a lot of sense ΔEΔt=hbar? So if the photon has an energy value of any inside the width it can cause a decay/excitation?"
] | [
"Technically, a photon of any energy can cause it, but the probability is only appreciable within the window ΔE around the energy."
] |
[
"What was the climate like on ancient Mars?"
] | [
false
] | Could there be places on Mars that had different temperatures like we have here on Earth. Like some places are cold and some are hot and then it changes seasonally day to day? Also, did ancient Mars have different continents like we do on Earth? Or was the land mass more attached like Pangea? Thanks! | [
"Prevailing research into this question: we can estimate how long ago Mars had a churning core and then make some good assumptions off that, combined with what the rovers have found. We know there’s still ice on the surface, but it seems to leak out of the crust and can’t exist long. It was probably covered in wate... | [
"There absolutely is water ice on Mars, even outside the polar caps.",
"https://www.jpl.nasa.gov/news/steep-slopes-on-mars-reveal-structure-of-buried-ice",
"https://www.science.org/content/article/ice-cliffs-spotted-mars"
] | [
"then the core solidified and the magnetic field dissipated",
"The core of Mars is still actually molten. The dynamo mechanism has stopped operating and there are a few possible reasons why exactly this might have occurred. The essence of it is that thermal and compositional convection is no longer strong enough ... |
[
"Are there any studies regarding learning, attentiveness, and the diminishing returns of cramming? I'd like to know more in order to deploy a robotic-like schedule-based learning session to maximize retention potential."
] | [
false
] | null | [
"Take any psych 120 course on memory, there's about 80 years of findings on this topic. The basic conclusion is: use distributed study (small bursts over a long period of time, not cramming) and multiple methods of encoding (read, take notes, write summaries, teach it to a friend, employ mnemonics talk about it in... | [
"Have you heard of ",
"Spaced Repetition Learning?",
" There are links to studies that prove this an effective method in that article.",
"Essentially, spaced repetition requires you to study things you forget more often, and study things less that you can more easily remember. This is most often done throug... | [
"well this is a object of research in social cognition. First off, no there arent any numbers or specific times that you have to follow, our long term memory is way to complex and studing it is a very complicated matter. dont expect any wonders!",
"\n I currently study this subject at university, unfortunately m... |
[
"If we somehow made a sheet of Photosystem II (with all of the necessary enzymes) and submerged it in water, would it produce an electromotive force like a solar panel? Would we be able to harvest the resulting protons for additional uses?"
] | [
false
] | null | [
"It's hard to comment on this - the photosystems require gradients across the membranes in order to create molecules that store energy. Technically, the answer is no, because all a flat sheet membrane with the enzymes embeded would do is to create ATP, which we don't really have a good means of converting into ele... | [
"Could you collect the protons or would you have to use them where they are staked up. "
] | [
"You could... but protons are just H+.... which is an acid. Getting an acid isn't really all that valuable. What's useful in this case is creating the gradient between the acid on one side of the membrane, and a base on the other - because you can use that difference in acidity to generate energy. Just the same ... |
[
"What happens when a DC is introduced to an AC line without a capacitive coupler. (Dead short)"
] | [
false
] | - crude, simplified diagram to help out. Let me start off by saying that I am a technician, not an engineer, so my advanced theory is limited. Basically the control unit is fed AC signal from the generator, then processes whether the generator needs to ramp up or down. The exciter signal is sent to the generator via th... | [
"400Hz AC... 28V DC... is this an airplane?"
] | [
"Haha, you got me! "
] | [
"Without diagrams, major guesswork going on here but usually when you introduce DC to an AC system you are going to saturate the core (usually transformers but in this case a generator).",
"My guess is that the output waveform is rich in harmonics resulting from half cycle saturation (DC will only saturate in one... |
[
"What is the difference between fur and hair?"
] | [
false
] | This question is mostly in reference to pet hair/fur. What makes dogs with hair hypoallergenic? I know that fur has dander that people can be allergic to, but why doesn't hair have that same dander? Do they grow differently? | [
"Fur grows to a set length and sheds in sessional cycles. Hair will continue to grow until the folicle reaches an age point where it will pause, release the hair, then grow again. This is unique to each hair and not seasonal. The fir cycle causes more dander to be released and is more allergenic."
] | [
"So are you saying that because the amount of fur shed is just more than the amount of hair lost. So the dander could still be in the hair but much less just because there is less generated?"
] | [
"I get that. My question is more asking why hair doesn't have the same dander and grow cycle."
] |
[
"Why is a thermite fire + ice an explosive combination?"
] | [
false
] | null | [
"Plus, the thermite reaction is hot enough to split water into hydrogen and oxygen",
"This simply isn't true, and is rather misleading. Thermite does not thermally decompose any meaningful quantity of water, and even if it did, there would never be enough free hydrogen sitting around to cause a secondary explosio... | [
"Water expands over a thousand fold in volume when it flashes to steam. The extreme heat of the thermite reaction causes this to happen very quickly, throwing material in all directions. Plus, the thermite reaction is hot enough to split water into hydrogen and oxygen, the hydrogen can ignite in the air once it coo... | [
"I don't believe aerosolizing it will make a difference as it contains an Oxidizer. "
] |
[
"When I jump on a train or plane, why don't I move backwards?"
] | [
false
] | null | [
"Because the horizontal components of your momentum are conserved."
] | [
"So my momentum keeps me going with the train ? "
] | [
"Yes."
] |
[
"Why, when new experiments show phenomena that are not expected based on the initial hypothesis, is this hypothesis only tweaked and not completely discarded (serious question)"
] | [
false
] | One example would be when the bohr model was proven incorrect, but we only changed the electron to be a probability field instead of a point of orbit. Another is when we added the neutron to our atomic model, along with many changes to the standard model, including the new inquiry into another flavor of quark. It seems... | [
"Because that hypothesis was consistent with [maybe only almost] all previous experiments, presumably, and so it appears to have something going for it. In addition, it makes a good starting point. If you need new theory you have to start somewhere, so you build on what you already have. If you throw everything out... | [
"Changing the electron to a probability field wasn't just a tweak, it was a major revision of the entire model. Quarks were also a major change in nuclear theory. What makes you think they are accommodations?"
] | [
"Scientific models such as those you mention aren't just random guesses. Even at worst, they're educated guesses that make sense based on what we can observe. More generally they make predictions that we can and do test. The Bohr atom, for instance, provided a good explanation for emission lines.",
"This means th... |
[
"The negative side of the square root does not matter?"
] | [
false
] | I don't believe the title, but this is the impression people on the internet have been giving me when solving this math problem. I am not talking about sqrt (-6) I am talking about sqrt (36)=+/-6 Can someone give me an example why it is important, I mean why would we be taught that the sqrt (36) is +6 and -6? The probl... | [
"The square root symbol is just an object that we made up to keep track of certain quantities. The equation x",
"-A=0 has two solutions in the real numbers for A>0. Luckily we know that if x=b is a solution (so b is a number so that b",
" then x=-b is ",
" a solution. This says two things: 1) We just need to ... | [
"what do you mean \"never take the negative\"",
"Have you ever used the quadratic formula to solve for the roots of a quadratic? congratulations...you used both solutions of the square root."
] | [
"I am talking about sqrt (36)=+/-6",
"sqrt(36) = 6 only. sqrt(x) is always positive for x > 0. You are correct the sqrt(x) function can only have one value.",
"Can someone give me an example why it is important, I mean why would we be taught that the sqrt (36) is +6 and -6?",
"I suspect you're misunderstandin... |
[
"How does docking really work?"
] | [
false
] | [deleted] | [
"It all depends - are you using the Clamp-o-tron Jr or Sr? Just kidding..",
"It's basically a system of mechanical seals/latches and locking parts. There are no magnets, it's pretty much all mechanical or electric-motor assisted. Unlike KSP, real astronauts have to hit the docking port perfectly perpendicular ... | [
"Couple things: Magnets do not mess up computers. They can affect data stored on magnetic storage (mechanical hard drives), but do not affects SSD hard drives or the rest of the computer.",
"Which spacecraft are you talking about docking? To the ISS?"
] | [
"Depends on what kind of hardware you're talking about but it's usually a mechanically locked system.",
"Here's a lot of detail about the Common Berthing Module used on the International Space Station.",
"And here's a 60 page paper on the history of spacecraft docking and berthing mechanisms as related to the I... |
[
"How does an appendage completely go away in evolution?"
] | [
false
] | null | [
"There surely have been vertebrates with an unusual amount of limbs. The problem is that these specific animals would almost certainly have died without procreating, thereby eliminating the variation that caused the abnormal limb growth/loss.",
"In other words, it surely has happened, but it's ridiculously improb... | [
"On top of this natural selection of normal variability, or a favourable mutation will play a huge role in the disappearance of traits.",
"If the loss of a trait is favourable under an extinction pressure, the percentage of the population that show a reduction or loss of that trait - due to natural variation, or ... | [
"You'll often see marine mammals with mutations that turn back on the DNA for legs and they grow odd malformed stumps where legs used to be.",
"There are a few species of lizard which have two but not four legs. There are other lizards (not snake but lizards) which have no legs.",
"I suspect that if we had a f... |
[
"When someone gains weight how does the body determine where to distribute fat?"
] | [
false
] | I assume it's mostly genetic (i.e. some people just tend to gain weight in their stomach or thighs etc) but, is there any science behind fat distribution? Do certain foods (i.e. foods with "good" or "bad" fat) promote better fat distribution/a more attractive body with less flab and whatnot? | [
"Thank you. Sample sizes of SIX? Sounds like a very reliable study. And the ONLY aspect of diet monitored and controlled was the type of fat consumed? How does that even qualify as a control? A real control would have them keeping an identical diet for the entire time other than the type of fat consumed.",
"This ... | [
"Thank you. Sample sizes of SIX? Sounds like a very reliable study. And the ONLY aspect of diet monitored and controlled was the type of fat consumed? How does that even qualify as a control? A real control would have them keeping an identical diet for the entire time other than the type of fat consumed.",
"This ... | [
"this NEEDS to go to /askshittyscience"
] |
[
"Can we artificially stop an action potential from propagating?"
] | [
false
] | What I'm referring to is if there is some electrical way to it, analogous to how a pacemaker is able to stimulate cells and generate an action potential, is there some electrical device or such that can stop one? I realize that there are chemically or simply physically (damaging the cells, blocking gap functions etc.) ... | [
"I have never heard of such a thing. An artificial action potential occurs because a certain threshold voltage potential of the cell membrane is overwhelmed. When the voltage difference between the cell environment and the interior of the cell exceeds the threshold, ion channels initiate the action potential. To st... | [
"You can electrically provide an external opposing voltage source and reduce the potential difference below whatever the threshold is."
] | [
"Can you explain this in a little more detail?"
] |
[
"What's the faster spacecraft we could create with current technology? Could we build a tiny spacecraft that reaches 0.6c?"
] | [
false
] | Suppose we find an exoplanet that is very likely to contain life and we want to send a probe to take close-up pictures of it. I've heard that most of the energy required to accelerate a spacecraft comes from having to accelerate the fuel itself, but what if we simply shot it like a canonball? Playing around with the nu... | [
"You've got issues with your units, amongst other things.",
"Ignoring special relativity, kinetic energy is 1/2 m * v",
" So the kinetic energy of a 1kg spacecraft at 200000 m/s is ",
"according to WA",
", 2*10",
" J.",
"However, this equation is incorrect at high speeds. We need to use the special rela... | [
"It's not inconceivable that one could build a very long (but technologically relatively simple) mass driver somewhere in the vacuum of space that could accelerate small objects up to significant fractions of c. It would be essentially a massively scaled-up linear particle accelerator, and we already know how to bu... | [
"My guess is that for that to be feasible, you would have to accelerate very, very slowly or find some new way to generate the absolutely massive amount of energy required to do it quickly."
] |
[
"First case of sexual reproduction?"
] | [
false
] | Is there a time period, or less likely, an actually case of the first sexual reproduction? When did organisms make the switch from asexual and start exchanging genetic material between each other? Did this then, over time, develop into two distinct genders? | [
"What are some examples of polysexual mating systems, that sounds crazy cool and I'd like to read more."
] | [
"What are some examples of polysexual mating systems, that sounds crazy cool and I'd like to read more."
] | [
"True, I didnt consider other diverse organisms with relation to gender.\nSo no clear cut answer as of yet?\nI had assumed that the process would have been a step up from the Horizonal gene transfer methods which are displayed in bacteria, but since sperm and ovum are required it would have to be a multicellular pr... |
[
"A metal plate with a hole in it is heated up and expands. Does the hole become bigger or smaller?"
] | [
false
] | Yeah what the title says | [
"Check out ",
"this thread",
", which is the reverse of what you asked.",
"The hole will expand when heat is applied. A few comments in that thread gives a good thought experiment: what if, instead of cutting a hole in the plate, you simply draw a circle on the plate? You can infer from what happens to a flat... | [
"One other idea: all of the atoms at the circumference of the hole will get further apart. Therefore, the hole will expand."
] | [
"Assuming the material is isotropic (homogenous without any directionality or preference for a particular axis), the angle between the two faces of the V-shaped cut will remain constant.",
"Not all materials are isotropic. Wood, fiberglass, and single-crystal materials like silicon wafers are classic examples of... |
[
"I'm being told, reading without light and watching tv without light is bad for your eyes, is that so?"
] | [
false
] | I feel like there is not much to it, and it's just another case being overprodective but what das think? | [
"In 2007, the idea that reading in dim light ruins eyesight was named one of the seven medical myths that doctors are most likely to believe. The study, published in the British Medical Journal, revealed that reading in low light does not damage eyes, but rather causes eye strain. ",
"Found ",
"here",
". And ... | [
"It's damaging in the sense that it's transient discomfort/pain like when you strain any muscle from over-exertion. You will not be worsening your vision however."
] | [
"Isn't exercise a repetitive strain on your body?"
] |
[
"How does a neck muscle strain cause a headache?"
] | [
false
] | null | [
"Cervicogenic headaches are thought to be caused by connective tissue bridges between the sub-occipital muscles (specifically rectus capitis posterior minor, and now possibly rectus capitis posterior major) and one of the layers of tissue that coats the brain. ",
"Our brain does not have nociceptors, aka. pain re... | [
"often times muscles develop trigger points, which essentially are knots in the muscle, typically due to repetitive use of previous trauma. These trigger points have a typical referral pattern. A lot of muscles in the neck (upper trap, SCM, suboccipitals) refer pain to the head. ",
"When you strain your neck, ... | [
"I think you believe headache originates from the brain. It does not, the brain in itself has no pain-nerves, the pain is from other tissue and often the muscles around the head."
] |
[
"How do you discern alpha helices and beta sheets in a string of amino acids?"
] | [
false
] | null | [
"http://www.molbiol-tools.ca/Protein_secondary_structure.htm",
"You would use some sort of computer algorithm.",
"http://www.sciencemag.org/content/260/5114/1637.abstract",
"Some amino acids are more likely to form alpha helices.",
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1299714/",
"Alanine has the h... | [
"http://www.ncbi.nlm.nih.gov/pubmed/7179570",
"You can look at them with electron microscopes.",
"http://www.ncbi.nlm.nih.gov/pubmed/12966187",
"They were first predicted from crystal structures and molecular theory by Linus Pauling. X ray diffraction was used to analyse them, though they couldn't see them di... | [
"Thanks, but I meant given a text string of amino acids how would you tell which sections form helices and which form beta strands. "
] |
[
"Why can't numbers stations like UVB-76 and The Backward Music Station be triangulated?"
] | [
false
] | I just read a little about the numbers stations and quite often there were clues to the origin and clues that some sources might have been moved. But why with all the hobby-numbers stations-hunters out there can't the sources be found? | [
"OOh, ooh, I can answer this. Sorry I'm not a real scientist, just someone that spends a lot of time with radios and transmissions. ",
"The simple of it is that numbers stations are very hard, by design, to triangulate. To triangulate a broadcast you need time, the broadcast needs to be consistent, and you have t... | [
"The wavelengths involved also make triangulation difficult.",
"Shortwave transmissions (between about 1MHz and 30MHz) are ",
"reflected back to earth",
" by the upper atmosphere, allowing them to travel huge distances if the conditions are right. As the signals bounce between the ionosphere and the ground, t... | [
"It appears that UVB-76 has been triangulated already.",
" Or at least the location is known. I am not an RF engineer though, so perhaps someone can lend some more insight. "
] |
[
"If a binary star system began to swell into red giants at a similar time, what would happen? Would the stars envelop one another, collapse, or remain separate bodies and then begin to shrink into red dwarfs?"
] | [
false
] | I'm curious as to what would happen if a binary star system began to turn into red giants at a relatively close time frame, if not simultaneously. Are binary stars even close enough that, if swollen into red giants, they would touch? If they did touch, would there be some sort of reaction? Would they eventually envelop... | [
"If they're close enough, the outer layers would engulf one another, forming a contact binary system. The two cores would share a common envelope of outer atmosphere. From there, it's possible that it could evolve into an accreting binary system.",
"Also, as a side note, the phase after red giant would be ",
... | [
"They can. When that happens they can merge into one star or be one star, but with two cores, depending on how close they are. If they remain as one star or two separate stars would depend on if they have one or two cores.",
"What's even cooler, imo, is when a binary system is a white dwarf and a red giant. The r... | [
"The masses of the two stars wouldn't increase so the gravitational effect would be zero. If our star became a red giant it wouldn't pull on us any differently than it does now. I may be wrong, but the increase in size vs the distance between binary stars seems negligible, but I am very ready to be schooled on th... |
[
"Human gender distribution sits at around 50%. Are there any species that live with an extremely lopsided distribution?"
] | [
false
] | null | [
"Ants and bees."
] | [
"This question has been asked several times before. Also you mean sex, not gender. Gender is defined as a social construct, sex is biological.",
"An approximately 1:1 sex ratio is an evolutionarily stable strategy as predicted by ",
"Fisher's Principle",
". Specifically, the effort put into producing males vs... | [
"From my experiance a hatching egg still has a 50% chance of getting a male. Male chicks just get picked out and.. disposed of."
] |
[
"My friend said \"It takes 7 years to digest a maraschino cherry\" and this was the stupidest thing I heard all week- but I need SCIENCE! to help me"
] | [
false
] | Nothing would convince my friend that this is not true short of a complete explanation as to why it's impossible or actual research. Explaining stomach pH, gut bacteria, functions of the digestive tract, etc. I am bothered by this, probably more than I should be. I need your help so that I can start sleeping at night ... | [
"Nothing will convince your friend if \"stomach pH, gut bacteria, functions of the digestive tract\" don't. But for you, so you can sleep at night, I went and looked this all up on the Intarwebz. ",
"Basically, you make a maraschino cherry by taking a normal cherry and preserving it in brine, which is salt water,... | [
"There's nothing in the cherries that would make them take any longer to digest than a regular cherry. ",
"While this is childish, and I wouldn't recommend it, you could simply eat a whole lot of cherries and when your body excretes the remains, that would be proof that they digested. I suppose this is the more... | [
"Explain to your friend that you can swallow a coin (far less digestible than a cherry) and it will pass in a day or two. "
] |
[
"How much radiation does a single banana give off? How many bananas would it take to kill someone and how long would that process take?"
] | [
false
] | [deleted] | [
"You basically couldn't kill someone by just piling bananas around them. The amount of radiation you need to get someone to kick the bucket is on the order of 2-5 Gy (joules per kg). Even using natural K metal (with a small % of K40), being surrounded by an infinite sphere wouldn't even come near a harmful dose. Yo... | [
"Ahh yes, Banana Equivalent Dose. My professor gave me a hard time when I joked about this one one day. Now look at it making a practical comeback. ",
"If you consider that 1 BED is typically taken as 0.1 microsieverts, that means eating 10 bananas will get you to 1 microsievert. If the maximum allowed radiation ... | [
"Now this response is what I was really waiting for! Thanks dude with the strange banana knowledge! "
] |
[
"Monsanto decision and the defenders?"
] | [
false
] | null | [
"What exactly are you asking?"
] | [
"I am trying to understand why part of the scientific community is coming out in defence of Monsanto and the 'science' when the courts have accessed documents that put into question any validity of existing science concerning Monsantos product, and asking is there something I've missed that makes the court findings... | [
"Ah. Such questions are better suited for our sistersub ",
"/r/asksciencediscussion",
". Please post there instead."
] |
[
"What are the scientifically-viable, evidence-backed methods for clinical psychology to treat depression?"
] | [
false
] | I've been shopping for a therapist, but I see so many weird techniques and phrases that seem borderline alternative medicine to me. Is there a good place to educate myself on this? I'd like some experts to chime in on evidence backed methods of psychology. Too much quackery to wade through. Thanks! | [
"There are a good deal of evidence-based treatments, but they generally all revolve around the same theme: ",
"Cognitive-behavioral therapy",
". Some versions are more cognitive (",
"Rational Emotive Behavior Therapy",
"), some versions are more behavioral (",
"Acceptance and Commitment Therapy",
"). Th... | [
" Psychoanalysis and psychodynamic are Freudian-based therapies. Psychotherapy is a general term for treatment. Don't get them confused! Also, just about anyone can call themselves a therapist, psychotherapist, or counselor. However, \"psychologist\" is a legally protected term that means they have a doctoral degre... | [
"I shopped across three therapist and have since gone to two, and may drop both and start shopping anew.",
"The three I just met:"
] |
[
"If sound waves travel most efficiently through solid objects, why do I close my door when I want not to be heard?"
] | [
false
] | null | [
"I'm not sure what you mean by \"efficiently\", do you mean faster? If that is the case - it is irrelevant. The speed has nothing to do with the volume, the volume is related to the amplitude of the sound wave - not the rate at which it travels. ",
"The sound has to travel between different mediums: air-door(woo... | [
"They travel better through solid objects, but they lose a lot of energy when transferring media. So, sound in your room travels through the air, then transfers into your solid door, then back into air (since interior doors are hollow), then back into the other side of the door, then back into the air on the other ... | [
"Sound travels better through solid object, the problem occurs when sounds travels between two different mediums. Part of the sound energy is reflected, part is absorbed (depending on the frequency of the sound). The bigger the difference in the speed of sound in the two mediums, the more is reflected. ",
"Whe... |
[
"Screws/Bolts: Apart from length and width, why are there so many different threads?"
] | [
false
] | I can see why the bit sticking out of the shaft might need to be thicker to stop the bolt coming out, but don't know why you get 40 "lines" on one and 20 on another? What is most perplexing is why the angle of the thread is not the same? Does it affect the force used to lock or unlock the nut? Bit rambling, but would l... | [
"Broadly speaking, we can divide screws into wood screws, sheet metal screws, and machine screws. The first two are designed to go into unthreaded holes (in wood or sheet metal, respectively) and form threads in the material as they go. They have coarser threads than machine screws. In the case of wood screws, a... | [
"Most bolts are specified by the thread pitch or spacing, as tpi threads per inch or mm spacing, as 1/4-20 (20 tpi) or m6x1.0 (1.0 mm). I think that the common thread pitches are most simply the finest/smallest that can be efficiently/economically manufactured, for a given bolt diameter. As thread pitch is reduced,... | [
"When it comes to common machine bolts, there are coarse and fine threads. Fine threads have more \"lines\" per inch.",
"That makes them stronger because of greater contact area, but also because fine threads don't go as deep into the shaft, so the shaft core is thicker. They also have less tendency to loosen bec... |
[
"How is it possible to see the first light of the universe?"
] | [
false
] | Moved from AskReddit... OK, watched How The Universe works yesterday and this has been bugging me. They talked about the COBE satellite and how it is able to "see" the first light of the universe. My question, and this relates to normal telescopes too, how is it possible to see (or hear) something that was created 13B ... | [
"The light comes from the time when the universe underwent a transition from opaque to transparent. When this happened, the source of blackbody light was literally everywhere, and the light shot off every which way. So there's light from everywhere, going everywhere."
] | [
"Once upon a time, the universe was filled with a hot, dense mostly-hydrogen plasma similar in many respects to the surface of the sun. As one would expect, this hot plasma emitted light. But at the time, the universe was so crammed full of ",
" that an individual photon couldn't travel very far before it interac... | [
"It helps if you stop taking your meds."
] |
[
"How does the moon Enceladus have water?"
] | [
false
] | So I've read briefly that for a planet to sustain liqiud water, it must be in the CHZ, however Enceladus is way out of this zone. How is this possible? | [
"Not to be that guy but it's not creating subsurface currents but the tides cause the planet to stretch which causes friction in the subsurface which in turn heats it up. The subsurface ocean on Enceladus is situated around the south pole where there are geysers that shoot out salt rich waters. I'm not sure why it'... | [
"That’s a pretty good question!",
"Research currently suggests that the oceans keep warm because of the tidal effects of Saturn. ",
"Naturally, Saturn, a super-massive object, will pull on the oceans of Enceladus, creating currents, but we believe that Saturn ",
" pulls on the core of Enceladus, effectively c... | [
"A planet needs to be in the habitable zone to sustain liquid water on it's surface, but Enceladus doesn't have liquid water on it's surface, it has liquid water below tens of kilometres of insulating ice where geothermal heat from radioactive decay and tidal friction can keep it liquid."
] |
[
"Does a large diameter, cylindrical, standing body of water, perfectly level and still, slowly rotate on its own axis *inside* its container due to the motion of the planet?"
] | [
false
] | An observed phenomenon has not been easily explained and has caused much consternation and argument. | [
"You're right that this is a more complicated question than the pop-science articles would suggest. ",
"To give you a sense of how subtle the effect of Earth's rotation is, when I was learning geophysical fluid dynamics, we did a lab experiment draining a tank about 1.5 meters across and 5 cm deep, perfectly circ... | [
"Theoretically, in a perfect container (frictionless walls), i believe it should rotate. The reason is because the atoms nearer to the equator are moving faster than the atoms on the opposite side, this creating rotational movement. This is essentially the Coriolis effect. ",
"Now, could you make a ",
" setup... | [
"You don’t need a force to maintain a rotation. You just need suitable initial conditions."
] |
[
"There is no \"outside\" the universe; the concept of \"outside\" does not apply to the universe. There is no \"before\" the Big Bang, because the concept of \"before\" does not apply to the Big Bang. This has been stated here a thousand times. Could someone attempt to explain this?"
] | [
false
] | Last time it was said was Robotrollcalls post in the question "If you traveled in a straight line in space, would you eventually end up back where you started?" by zcsu05 | [
"There is no \"outside\" the universe",
"This is true by definition because \"the universe\" ",
" means everything. Everything rolled into one. How can you have something be outside the universe? If it's a thing, it's part of the universe.",
"The question \"what's outside of the universe\" typically comes ... | [
"What real numbers lie ",
" the real number line?",
"None. There is no \"off the real number line.\" The real number line consists of all real numbers. If a real number exists — three exists; seven exists; splorch is not a number and thus does not exist — then it lies somewhere on the real number line. The real... | [
"The difficulty with \"what ",
" before there was time ('which was started' in/by the big bang)?\" questions is that there can by definition be no events/actions without time.",
"This is where science and philosophy overlap. IMO, the philosophical explanation is that we've reached a point where our mathematical... |
[
"According to the theory of relativity, when I fly in a plane time goes a teeny tiny bit slower. When I go back to the ground, do I sync back up like setting a watch or have I \"lost\" time?"
] | [
false
] | I do not know too much about the theory of relativity and the concept of time (although I'd like to think I do) but I find it extremely interesting. Please feel free to tell me I am looking at it the wrong way or have it plain wrong. | [
"Well actually when you fly in a plane time goes a teeny bit ",
" than for people on the surface. If you were travelling in a fast car, then yes time would go by more slowly, or you would have ",
", i.e. your time would be dilated. But the fact that you're on an airplane puts you farther out of the Earth's grav... | [
"It can be either, depending on latitude, speed and direction of flight. See the results of the Hafele–Keating experiment ",
"[1]",
" where the clock on the eastward plane lost time and the clock on the westward plane gained time."
] | [
"There are two different things at play here, so the answer is a bit more complicated than you were hoping. ",
"First let's consider special relativity (which is what I think you mean by \"the theory of relativity\"). Imagine that we are both in space, far away from anything else, and that I'm floating still and ... |
[
"When generating electricity, can a magnet spin too quickly?"
] | [
false
] | Just thought about magnets spinning. Do they have a limit on how much fast they can spin? | [
"There is a practical limit of how fast you may want to spin a magnet...",
"If you plan on generating 60Hz (or 50Hz) electricity, the fastest a generator can rotate is 3600 RPM (or 3000 RPM).",
"f=np/60 where f=frequency of generated electricity (Hz), n=speed of generator (RPM), p = number of pairs of magnetic ... | [
"Electricity generation by magnetic induction is based on the quasi-static approximation of electromagnetism. It assumes that a changing magnetic field induces an electric field, but not vice versa. If a magnet spins too fast, the quasi-static assumption breaks down and electromagnetic radiation is produced. Rad... | [
"you're increasing its kinetic energy. the energy has to come from somewhere. since accelerating a massive object to the speed of light requires infinite energy, you'll never be able to accelerate it such that the fastest part moves at the speed of light. that's the limit. the practical limit is of course quite sl... |
[
"I was told to consume fish oil daily by my psychiatrist for ADD, as apparently this improves brain signal communication and ultimately leads to better concentration & thought process. Is this true?"
] | [
false
] | null | [
"Fish oil is thought to have many great properties. Unfortunately, most of those claims haven't been proven. It can help your joints, your cholesterol, and other things.",
"I haven't heard what your Dr. said, but basically, it's worth a try, since there are usually no bad side effects with taking the medicine. If... | [
"Also, as someone who used omega-3 dietary supplements in several research projects, I would recommend eating fish as source of omega-3. Those supplements are not regulated by FDA to same degree as drugs and their content quality is not guaranteed.",
"Edit: There are prescription level sources of omega-3 such as ... | [
"Omega-3 study results supportive but not definitive",
"Your Brain on Omega-3",
"Scientists Learn How Food Affects The Brain: Omega 3 Especially Important",
"Omega-3 fatty acids -- found in salmon, walnuts and kiwi fruit -- provide many benefits, including improving learning and memory and helping to fight ag... |
[
"Scientists and Engineers of Reddit, explain why the following statement is either true or false."
] | [
false
] | "We have the technology today to provide all of our energy needs via sustainable sources such as wind, solar and geothermal. All that is lacking is the political will." I read this the other day and found it both plausible and lacking. Hence, the request for the opinions of those of greater knowledge. | [
"Apologies if this becomes long winded.",
"I will address the electrical aspect of energy in this post.",
"For an energy source to be dependable it most have several factors.",
"Constant",
"Ease of call up",
"Ability to scale.",
"Now on to electricity grids. An electrical grid operates on a frequency, t... | [
"It's not about politics, it's about economics.",
"Let's do the math on subsidies for fossil fuels and renewable energy in the last decade. (",
"Source",
")",
"Fossil Fuels: $10.3 billion annually",
"Renewable: $4.1 billion annually",
"In 2009, the US consumed 94.578 quadrillion BTU, which is 27.72 tril... | [
"Ok, how the hell does a post that doesn't even mention the trends in energy cost get the top response? Solar is dropping at an astounding rate.",
"Edit: nice ninja edit above with a throwaway line about cost trends.",
"The best politicians can do is give incentives for research and development in the field in... |
[
"Human development without social interaction"
] | [
false
] | I had a strange thought earlier today that I thought I'd share in an attempt to seek answers. It may seem a bit silly or strange but I'm highly curious with this idea, so allow me to fully explain to the best of my abilities. If and when possible, imagine a human that was created or born to be part of a ground-breaking... | [
"You would get one of these:\n",
"http://en.wikipedia.org/wiki/Feral_child"
] | [
"From the interesting annals of history, via wikipedia. ",
"An alleged experiment carried out by Holy Roman Emperor Frederick II in the 13th century saw young infants raised without human interaction in an attempt to determine if there was a natural language that they might demonstrate once their voices matured. ... | [
"That's the most evil thing I read someone do to other human beings. And there are many biographies of bin laden out there today.."
] |
[
"does donated blood have a use-by date? And if so what is happening in the blood to make it no longer useable?"
] | [
false
] | null | [
"Not an expert on blood, but I was at a recent talk by someone who is working on instrumentation to monitor quality of donated blood.",
"Early in the talk, he described how donated blood is separated into several components (e.g. red blood cells, platelets), each of which has a different shelf life. Platelets are... | [
"I looked this up as I donate blood and am interested to know the answer as well. Apparently blood can be stored refrigerated for up to 21 or 35 days depending on what it is treated with. Over time the blood does deteriorate and they will try to use the most recent blood available for transfusions etc.",
"It can ... | [
"Are you sure that's not the expiration date of the donation set? The bag includes preservatives that do have a limited effective shelf life. ",
"AFAIK, frozen plasma has a shelf life of only six months. "
] |
[
"Does anyone know about the origins of agriculture?"
] | [
false
] | null | [
"It's a factual book but written in a very accessible way. It accompanies the BBC series of the same name, so it is designed to be entertaining."
] | [
"The Ascent of Man by by Jacob Bronowski",
" is a classic which deals with agriculture and much more besides. It's a great read, too."
] | [
"Thanks! What kind of read is it? Does he create an image of \"The Ascent of Man\" or is it more of a factual/theoretical observation?"
] |
[
"When interacting with the more intelligent animals, do they realize that we, as humans, are a much more intelligent species? Or do they simply view us as another animal?"
] | [
false
] | When interacting with the more intelligent animals, do they realize that we, as humans, are a much more intelligent species? Or do they simply view us as another animal? i.e. When interacting with a Chimpanzee, would it realize that I am more intelligent than it... what about a Dog... a Cat? (I assume it's less likely ... | [
"I wouldn't necessarily say that other animals view us as the more intelligent species. A large part of the whole idea is that animals aren't going to really make any high-level inferences on what actions you preform. When animals and humans communicate, all the animals are understanding are the actions preformed b... | [
"To that I would add: (first let me say, I'm not an expert, but) based on my observations of other, relatively intelligent animals, specifically traditional pet animals, it's not so much our intelligence that they consider when they \"think\" about us; it's our effectiveness at addressing their needs. ",
"I belie... | [
"My dog looks at me when he can't figure something out (like get a lid off something with food in it. I saw a study about dogs vs wolves in this regard, let me see if i can find it",
"here it is. ",
"http://psyc.queensu.ca/ccbr/Vol2/Kubinyi.pdf"
] |
[
"Can we call any star that has planets orbiting it a 'sun' or is this only the name of the star we orbit?"
] | [
false
] | I got into a bit of a debate in a subreddit a while ago as to whether or not a 'sun' is our star, or a star with orbiting planets. While many of the sources I found offer mixed results, wikipedia seems to claim that it is infact simply the name of . While some dictionaries seem to claim that it is also a star with orbi... | [
"additionally, most stars already have proper names or designations."
] | [
"additionally, most stars already have proper names or designations."
] | [
"Well, that would depend ",
" on your definition of \"most\"!"
] |
[
"Why is the time scale normalised all over the world while most other scales aren't?"
] | [
false
] | I guess a historian can answer this. What is the history about it? | [
"Why don't you think that other scales aren't normalized? Most of the world uses the SI system, in which we all agree on the same standards for all physical units."
] | [
"Also, time is not normalized all over the world. Ethiopia, for instance, has an entirely different calendar and sets 12:00 to be at sunrise."
] | [
"I did some reading up on this out of curiosity some years back, and while I don't recall enough of the details to be authoritative, here's how I remember it.",
"The year is a natural unit of time: a cycle of the seasons. So it's obvious. The month is similarly obvious, being based on the cycle of the moon, thoug... |
[
"Why are there no physical laws dependent on the derivative of acceleration?"
] | [
false
] | I have also heard this described as "there are no physical laws that can induce a change in acceleration". My general relativity professor mentioned this during a lecture last semester but never really went into it, except to say that there is a proof or theorem that this is the case. Can anyone shed any light on this? | [
"Two assumptions:",
"1) The state of a mechanical system is determined by the positions and velocities of all its parts.",
"2) The principle of least action.",
"From these two postulates you can derive the Euler-Lagrange equations that describe the dynamics of the system. This is done in the framework of Lagr... | [
"The equations of motion do not depend on jerk. That's what the professor meant. Jerk does not need to be 0 always. That's irrelevant and this does not answer the question."
] | [
"It is called Jerk.",
"If you push on a wall, it takes a fraction of a second before you apply the full push. Your fingertips will squoosh slightly as you begin to push. How long the squooshing takes determines the jerk. If you push on a wall very slowly, you can actually feel your push increasing. In such a case... |
[
"I haven't had my period in two months, I am sure I am not pregnant. Can anyone help me out?"
] | [
false
] | null | [
"This is not the right subreddit. See guidelines ",
"here",
"."
] | [
"Thank you I am new to reddit and I wasn't sure. "
] | [
"There probably exist several other subreddits that may be more informative. We have a strict no medical advice policy here. If anyone is concerned for their health, please see a doctor. "
] |
[
"What goes on in the brain when reading music?"
] | [
false
] | Just to make clear. I would like to know what happens when someone is sight reading music. 1. Is there a lot of activity? Does this depend on how experienced the reader is? 2. What parts of the brain are activated? Visual? Auditory? 3. How does this compare to someone playing but not reading? I am a curious music stude... | [
"Here's a link to an excellent Radiolab podcast about this"
] | [
"I'm a professional accompanyist/sight reader, so not an expert on the neurophysiology, but I can pipe in on other parts.",
"I would say it's most akin to reading out loud, but a little more complicated. When I sightread, I don't read notes individually. Chord structures are read as chords rather than individua... | [
"I'm not an expert but it's probably very similar to language processing. There are very close parallels in reading or writing computer languages. "
] |
[
"Why is making a fist so difficult sometimes, particularly in the morning?"
] | [
false
] | null | [
"In REM sleep, REM atonia occurs. This is when inhibitory neurons in the brain stem and spinal cord inhibit motor neurons, preventing movement. There could be some residual effect from this, such as from neurotransmitters remaining in the synaptic cleft. This would induce a temporary muscle weakness that, as the ne... | [
"This sounds like it has validity, but it also occurs to me randomly during the day. I thought I remember hearing somewhere that a chemical produced by your brain causes your muscles to not contract fully, but I may be wrong."
] | [
"Sorry, I have no answer to your first question. Regarding your second question, yes. "
] |
[
"How much mass does the sun lose over its lifetime as a main sequence star by emitting light?"
] | [
false
] | How much heavier was the sun at the beginning of being a main sequence star to the end? It should lose mass, since it emits light and conservation of energy etc. | [
"Here's",
" an article by Phil Plait that addresses the question.",
"Apparently it loses about 4 million tons per second from fusion. It also loses about 1.5 million tons per second due to the solar wind. ",
"Over its 4.5 billion year lifetime so far, it has lost 10",
" tons of material (the mass of 100 E... | [
"I consciously recognize that I'm completely incapable of reconciling the sheer size of most celestial bodies, but comments like this really drive that home. As I read through \"4 million tons per second\", I thought \"wew, that's a lot\", and as I got to \"mass of 100 Earths\", I thought \"that's not very much\", ... | [
"In astronomical terms, a \"ton\" is a uselessly tiny unit of mass.",
"It's sort of like notating your body's height in ",
"ångstroms",
"."
] |
[
"What would it take to slow down or stop 2012 DA14 (next years asteroid)?"
] | [
false
] | I'm curious as to if it would be possible given enough time and energy to slow down or stop an asteroid as it neared earth. I want to know if we can stop it and bring it into a stable orbit around earth so we can study it more effectively. | [
"I would rather have it crash into Mars to give it some water and create an atmosphere."
] | [
"This isn't the correct robust way to get the answer, but it will give us a ballpark answer. Looking at the image in on the ",
"wiki",
" page and assuming it is to scale, the velocity of the asteroid relative to Earth is about 30,000 km/hour or 500 km/s. The mass was quoted as 1.3E8 kg. Again, for order of m... | [
"You make a good point with this calculation. However, I think what we really need to think about is the ",
" we stop it. If we just fired a nuke at it, the asteroid would just blow up in to a billion smaller pieces, but still be travelling (mostly) in the same direction (all of the energy would be used up in des... |
[
"Does adding more grounds to drip coffee make the caffeine content stronger?"
] | [
false
] | Hello, I've had an ongoing debate with a colleague who regularly adds excess grounds (approximately two cups) of medium roast Green Mountain coffee to a six cup drip coffee pot. Not only does their coffee taste bitter, but they typically also have grounds seep into the pot while brewing (personal pet peeve). Did some r... | [
"Caffeine is very, very soluble. Roughly 2.2 grams per 100mL of water at 25 deg C.",
"Your average cup of coffee has perhaps 100mg in 250mg. A \"saturated\" cup of coffee would have 5.5 grams of caffeine in it, which is about half as much that is required to kill an adult. It would be... unpleasant to consume.",
... | [
"Place pH test strips near coffee maker. Make a chart near coffee maker featuring test colors from acid to alkaline. Have coffee consumers test coffee and vote for preferred pH level by placing a check/x next to acceptable pH.",
"You should be able to gather enough data to set a point where most consumers find th... | [
"This is the only argument you need - that their personal preferences are out of line with everyone else's, and they are being selfish and inconveniencing others. A communal coffee pot should be brewed to communal tastes.",
"This is what I was going to say. Why does it matter how much caffeine is in the coffee? I... |
[
"How can black holes exist after proton decay has happened. Black holes are also made out of particles so why do they exist longer?"
] | [
false
] | I'm reading Adam Laughlin's Five Ages of the Universe and he writes that after the degenerate era, when all protons are decayed, there will only be black holes left. How can this be, black holes are made of particles as well right? | [
"No, black holes are not made of particles. Black hole are their own thing. Black holes also decay, but with a different signature and in their own long time - through Hawking radiation.",
"In fact, you could argue in a somewhat modern perspective that in our low energy Universe there are only two type of fundame... | [
"I don't want to nitpick, but as I don't know the background of ",
"/u/BlueLightsInYourEyes",
" I feel like there are some things that should be mentioned here:",
"As far as we know protons are ",
". Never has anyone observed a ",
" proton decay and according to the Standard Model of particle physics they... | [
"That protons are stable is very unlikely, since baryon number is an accidental symmetry of the standard model. It's not excluded completely but you'd have the hardest time building a GUT with no proton decay.",
"The current experimental lower bound on proton lifetime is still compatible with most supersymmetric ... |
[
"Why does epigenetics only affect transcription, and not replication?"
] | [
false
] | [deleted] | [
"That's not quite accurate. Epigenetics is concerned with alterations in a cell/organism which are separate from a change in the sequence of DNA.",
"The critical difference here is that epigenetics CAN affect replication if an epigenetic event occurs in a region of the genome responsible for manufacturing the rep... | [
"It does; heterochromatin is locally uncoiled in the region of replication by a protein you just mentioned (helicase). This region expands during replication and results in a widening of the unwound region bounded by replication forks on either end. Prior to this process beginning, histones deassociate from the DNA... | [
"It does; heterochromatin is locally uncoiled in the region of replication by a protein you just mentioned (helicase). This region expands during replication and results in a widening of the unwound region bounded by replication forks on either end. Prior to this process beginning, histones deassociate from the DNA... |
[
"Wouldn't you die instantly after entering the event horizon of a black hole because matter can only travel in one direction? Wouldn't you brain signals and blood flow not work anymore?"
] | [
false
] | Nothing can go back from the event horizon of the black hole right? So imagine you are falling into one. Your blood, neurological signals, and even small movements inside your individual cells pass back and forth, from the front of your body to the rear. When you are past the event horizon matter can only travel in one... | [
"No, it's not that nothing can move backwards, it's that nothing can ",
". That's a subtle but important distinction. If I throw a ball into the air, it moves up away from Earth for a time - but it doesn't escape, it comes back down. Further, a person in freefall across the event horizon has every part of their b... | [
"This is a really excellent answer and it is almost entirely complete.",
"The only thing I would add is that since the event horizon is the point at which information becomes \"irretrievable\" from a black hole, we cannot say ",
" what would happen in a physiologic sense if a person were to pass through the eve... | [
"Lets try it another way: if you were inside a sealed room (inside a spaceship), and the spaceship fell through the event horizon of a very large black hole, there is no measurement you could make that would tell you when you went through the event horizon. Except that hard X-rays from the accretion disk would dest... |
[
"If you develop antibodies for a virus only a few days after infection, why is it that an antibody test cannot detect an active infection?"
] | [
false
] | Assuming that any infection (specifically viral) will remain active for at least some time after you have started to develop antibodies, wouldn't a positive antibody test and ongoing symptoms be enough to determine you have an active infection? I have seen many posts regarding the difference between COVID infection and... | [
"How long it takes for antibodies to development (IgM/IgG) varies by the infection. For tuberculosis, it takes weeks for your body to develop IgM antibodies. For influenza, it can take 2-3 days to develop IgM antibodies. Most textbooks write somewhere around 4-7 days for development of IgM antibodies for most infec... | [
"Not only this, but tests to detect anti-SARS-CoV-2 IgM have not been very successful at all, with one manufacturer even admitting they can't produce control material (needed for labs to prove the test even works). Detection of IgG by ELISA is simply the most reliable method right now, and it's a fairly involved pr... | [
"There are two main reasons:",
"Upon initial exposure to any immunogenic protein/particle (say a virus) your body will begin making antibodies against this protein. Initially the body will make hundreds of molecularly different antibodies to this protein/particle. Through a process akin to super accelerated natu... |
[
"What's the difference between laser and light?"
] | [
false
] | [deleted] | [
"A laser emits monochromatic, coherent and collimated light. \nThat means the light consists only of 1 frequency and not a spectrum of frequencies, like for example the sun produces. \nThe light is collimated, meaning the beam is very narrow. \nThe light is coherent, that means that the light emitted by the laser i... | [
"The main property of laser light is coherence. Coherence means that if we take several points separated in time or space and look at the phase difference between them, it should stay constant (or drift very slowly in practice). In other words, the more coherent the light is, the better we can see ",
"light wave ... | [
"A laser is a device which emits a particular type of light. Light is electromagnetic radiation. I'm going to assume this question was probing what's the difference between light emitted from a laser, and light that we're likely to encounter routinely in our environment.",
"Light as we normally think about it (b... |
[
"How much bleach should I put in 2 500 liters of water to render it safe for drinking?"
] | [
false
] | null | [
"You are asking how to make water safe to drink using a product that can potentially be toxic. This is by definition safety advice. Since we cannot control every single comment we do not want people to get hurt or sick because of what some random Reddit user wrote on ",
"r/askscience",
"."
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"medical or safety advice",
"/r/AskScience",
"guidelines",
"If you disagree with this decision, please send a ",
"message to the moderators."
] | [
"Trying hard here to comprehend how a question about the volume of bleach I need to add to a given volume of water in order achieve the right concentration to disinfect the water is about 'medical' advice. "
] |
[
"Why doesn't the asteroid belt condense into a planet/dwarf planet?"
] | [
false
] | So I read that there is already a defined 'dwarf planet' in the asteroid belt (the name escapes me). Why doesn't this gravity attract the other asteroids and evolve into a planet as the other 8 planets did at the start of the solar system? | [
"Ceres is the dwarf planet your thinking of. It's about a third the mass of the asteroid belt and only about 1% the mass of the moon. At this point the asteroid belt will not condense due to not having sufficient mass as well as being under the influence of Jupiter and Saturn.",
"Here's an older discussion ",
"... | [
"Correct, though it's mainly the work of Jupiter, as Mars is too small to have much effect. The tidal forces of Jupiter disrupt the asteroid belt, favoring high energy collisions and fracturing, rather than letting the debris coalesce into a planet. Add to that the occasional orbital resonance between the gas gia... | [
"As I understood it, the pull between Jupiter and Mars/Sun, disrupts it too much for anything to condense. Floating particles will always go toward the most massive sources, but in the early planet forming times, there were far less big things and a lot more free particles. The largest bodies in the belt cannot com... |
[
"when mammals develop in the womb of the mother they get their oxygen and blood flow from the mother right? so my question is where does the oxygen and blood flow come for birds and other species that develop in an egg?"
] | [
false
] | null | [
"There is no direct blood flow between mother and child in mammals. Their blood vessels come in very close contact, close enough to transfer nutrients, oxygen in one direction and CO2 in the other.",
"In eggs there is a small \"empty\" compartiment. Like an air bubble, that holds temporarily enough oxygen for the... | [
"To add to this, mammals are amniotes, i.e. originally had eggs very much like birds and lizards do, but mammal's eggs don't have shells anymore and aren't laid, they just stay in the mother's body until they hatch (except for platypus, that weird mammal that lays eggs).",
"All these eggs have two vascularized (p... | [
"Oxygen actually diffuses in through pores in the shell. And rather than having to absorbing nutrients etc from the mother, all the nutrients needed for the developing chick/baby reptile/baby monotreme come from the yolk."
] |
[
"Can a memory be spontaneously created, just as a Boltzman Brain could?"
] | [
false
] | This is a long shot, but I am attempting to understand how memories work, and how they could be created for a . My understanding a memory is a construction made by the intricate connections of neurons as used by a stimulus. So for example, I have a memory of smelling a rose, so neurons responsible for the smell of the ... | [
"Ok, this is a question on two levels - one about memory representation in biological systems (brains) and the other about the meaning behind the Boltzmann brain paradox.",
"Let's start with number 1. You are roughly right, but it’s a very simplified view of how memory works. In essence, it is very unlikely that ... | [
"Instead, what we will call the ‘representation’ of the rose is a complex pattern of distributed activity across millions of neurons - in other words, the smell of the rose does not reside in a single cell but in a network of cells that, when active in particular pattern, elicit the representation.",
"Distributed... | [
"Extrapolating that result, it seems reasonable to suppose that there might be a small collection of \"rose neurons\" that light up whenever a rose is encountered.",
"The problem is we don't know how far we can extrapolate the \"Jennifer Aniston cell\" result, though. It's nontrivial to argue that representationa... |
[
"Is there a 'baseline' time dilation throughout the universe, or does the gravity of galaxies & black holes distort it over vast distances? Is there an equivalent of 'absolute zero' in the sense of time dilation?"
] | [
false
] | [deleted] | [
"There are two levels of time \"dilation.\" One is from special relativity: The time perceived by two observers traveling with relative motion to each other will appear to be slowed. In this case either clock is \"equally\" valid",
"The other case is from general relativity ",
" the time dimension. In this case... | [
"The mathematical model to describe the expansion of the universe is based on the assumption that on a very large scale the universe is uniformly distributed with matter. This is a largely valid assumption as there is ",
" of space without anything at all. On average it works out to like a hydrogen atom per cubic... | [
"The mathematical model to describe the expansion of the universe is based on the assumption that on a very large scale the universe is uniformly distributed with matter. This is a largely valid assumption as there is ",
" of space without anything at all. On average it works out to like a hydrogen atom per cubic... |
[
"100-year-old light bulb?"
] | [
false
] | Today, I learned that there is a that has been glowing continuously for over a century. How is this possible? Why don't regular, more advanced light bulbs last as long? | [
"Formalities bro. All we want to know is how that thing has lasted for so long."
] | [
"Formalities bro. All we want to know is how that thing has lasted for so long."
] | [
"Low power (about 4 watts), robust carbon filament and a lack of thermal expansion/contraction cycles since it's left on.",
"4 watts isn't very bright (60 watts is a \"normal\" incandescent bulb), cheaper and easier to make filaments are used in modern bulbs and we turn our lights on and off."
] |
[
"What is worse for your body weed or alcohol? And why one is worst than other"
] | [
false
] | null | [
"Alcohol has ",
"cancer causing properties",
" and it’s use and abuse has a very long history of addiction, mental instability, and ",
"death",
". It can ruin whole families lives. It also has a “trickle down” effect where it can be abused by those that were abused by their alcoholic parents poor parenting.... | [
"Common wisdom will tell you alcohol is worse, which is probably the case but there are somethings to note about this statement. There is more evidence that alcohol causes more damage than marijuana partially because studying marijuana use is far more difficult. Marijuana use is less common, and illegal in most hig... | [
"\"Worse\" would depend on the method of intake, and the amount. ",
"Smoking a joint is worse than having a glass of wine. But downing a bottle of vodka is worse than taking a few drops of a tincture. ",
"In the end, alcohol being a CNS depressant that can kill you fairly easily, I'd have to say that alcohol is... |
[
"Do inland mammals introduced to salt water for the first time instinctively know not to drink it?"
] | [
false
] | Ok, I tried to Google an answer and didn't come up much. The question of what sea mammals drink has been posed here several times before. But after watching a viral video on Facebook of a baby elephant reportedly encountering the sea for the first time, my first question was "does it instinctively know it shouldn't con... | [
"It should be noted that the reason that humans and other mammals can't drink salt water has to do with the amount of salt per liter our kidneys can absorb. Salt water is about ",
"3.5%",
" sodium, whereas we can only concentrate our urine to about ",
"3%",
". In other words, for every drink we take of sea ... | [
"Very interesting! So could one \"safely\" drink 6 parts saltwater for every one part freshwater?"
] | [
"Not necessarily. \"Instinct\" is a really fuzzy notion, as there's a gradient between innate behaviors, innate perceptions, and things that can be learned really quickly and easily, because they are not 100% hardwired in the brain, but kind of \"sketched\" (probably because flexibility is often a good thing). Anyw... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.