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[Mass Effect] If the Reapers have been exterminating the Milky Way's sentient life every 50K years, what is the sentient life situation in other galaxies?
I'm assuming the situation in the Milky Way is quite abnormal. If the reapers are millions and millions of years old, what level of advancement are sentient life forms in other galaxies at?
59
The Reapers do not travel outside the Milky Way (except for their hiding spot), because it would probably take them more than one cycle to arrive. There will be a few stable civilisations in the other galaxies, which will be old enough to wipe the void with the Reapers. However, nearby galaxies like the Magellanic clouds probably get harvested too.
46
All philosophy is situation?
After reading Victor Frankl's "Man's Search For Meaning" it struck me that the philosophy that came out of the book seemed very much as response to his situation, and that is it no surprise that he didn't adopt a philosophy of something like Utilitarianism instead. This got me to thinking that most if not all philosophy in general comes in response to the world at large or a particular topic of concern at the time of the philosophy's creation and to the author's situation. So my question, is there any branch of philosophy that basically says there is no real philosophical rules, but rather any number of valid approaches exist depending on your environment or circumstances. I would call something like this "situational philosophy", and i theory your philosophy of life could change as often as your circumstances change. Apologies if this questions is unclear.
59
You might be interested in *moral particularism* \-- the view that there are no authoritative ethical principles, and that moral judgment consists of nothing more than deliberation about particular cases.
44
Why does humidity kill static electricity?
When I take off a fleece coat in dry winter you can hear it crackle with electricity but in the humid summer it doesn't. What is it about humidity that kills the static?
137
Static electricity on clothes comes from electrons separated (by friction of putting it on for example) from their original molecules. The separated electron acts as a negative charge, while the left behind molecule now has net positive charge. This local charge surplusses and deficits are what makes up "static electrity". As fleece sweaters are typically made of synthetic materials that are bad conductors of electricity, these separated electrons can not move on the surface of the sweater to reunite with their molecules and thus are kept separated. This makes the static electricity stay on the sweater. If you now introduce very humid air around the sweater, some of the water will condense into the sweater, improving the conductivity of its surface (if even by the smallest amount). Now the separated electrons can move around the surface and reunite with a molecule that is missing and electron, evening out the electric field at that point. This makes the static electricity disappear from your sweater.
70
ELI5: Why are there only 12 notes in music?
So I understand the formula for the major scale, and I understand the need for accidentals in order to preserve the formula for the major scale regardless of the tonic. I understand how this gives rise to the chromatic scale. What I want to understand is, from a physical/acoustical perspective, why there are only 12 tones in the canon of Western music. Since pitch is really wave frequency, aren't there an infinite number of possible pitches, and moreover, an infinite number of major scales that could be constructed from any of these? For example, between E and F, though they're only a half-step apart, aren't there, acoustically speaking, E and 1/2, E and 1/4, E and 3/4, etc.? Couldn't you construct major scales around any of these? How did we settle, for example, on a specific number of sonic hertz being a "C"? TL:DR: Why are there twelve keys in an octave on the piano, and how are the pitches assigned to these keys not completely arbitrary? http://en.wikipedia.org/wiki/Major_scale http://en.wikipedia.org/wiki/Chromatic_scale
18
It is all about the chords. Two notes played together sound pleasing when their waveforms line up nicely. Frequency ratios of 2:1 and 3:2 sound better than 13:9 or 23:17. 12, being divisible by 2, 3, 4, and 6, gives a lot of ways to hit these good ratios, in a way that 10 or 13 would not. Also, there are some musical traditions that divide the octave differently, with 18 and 24 being a common alternatives.
15
[The X Files] How much did Mulder and Scully make? What kind of performance reviews did they receive? Are they collecting a pension now?
20
In today’s money, FBI agents make 50k or so starting. This is about 25k 30 years ago. It’s a government job, so good benefits including a pension are part of the package. Mulder was top of his class at quantico iirc. Scully was recruited as an MD. So I’m guessing they got something like too starting pay, so maybe more like 30k in 1991, or 60k today. As seasoned/senior agents, they could make more, like twice as much. I’d guess Mulder probably didn’t get too many raises, but Scully might have. Realistically, they have comfortable middle class retirements, but aren’t wealthy. Mulder lived in a tiny apartment, so maybe he saved up, but he also just as likely spent his money trying to find the truth.
25
ELI5: why do things like metal and lava turn red when they are are hot?
125
It is thermal radiation. The thermal radiation that everything emits depending on temperature. Glowing orange red is the lowest temperature that emit visible light. The hotter it gets the whiter it gets and even hotter it will look blue. The light from a incandescent light bulb and the sun is black-body radiation but it is whiter at the temperature is hotter. Thermal radiation it emitted at all temperatures but it has to be over approximate 798 K (525˚ C, 977˚ F) to be visible. At lower temperature it is only infrared light and not visible. The heat you feel radiate from hot object at lower temperature is thermal radiation but in infrared. But with special camera often called Forward looking infrared (FLIR) in militery application you can see the thermal radiation from a human.
87
If we existed on the planet found orbiting Alpha Centauri, would we be able to detect the Sun's planets with our same technology?
Obviously it would be too hot to exist on, I'm just trying to grasp what sorts of planets we are able to discover at this time.
26
There are two primary methods for detecting planets, the transit technique and the radial velocity technique. The transit technique looks for dimming of the parent star as the planet crosses in front of it. This technique works very well for large planets (e.g. Jupiter) but is sensitive enough to detect even Earth-size planets. However, it requires continuous monitoring of the star (otherwise you'll miss the short-lived transit event), it requires detecting at least 3 transits to be certain that you're seeing the same planet in orbit, and it requires that the alignment between the orbit and the line of sight to the star be within a narrow range. This last requirement is a big problem as it means that only a fraction of a percent of planets in Earth-like orbits would be detectable, all of the others would have orbits which don't pass in front of their parent star relative to our view. On the other hand, the technique works just fine if all you want to do is get a better handle on the statistical probability of planets of various types. So if we were looking at a clone of our own Solar System out in the galaxy we might be able to detect Venus and Earth but the chances of that would be about 1 in 300 or so. The radial velocity technique is a bit different, it looks at the "forward" and "backward" motion of the parent star relative to us over time. If a planet is orbiting the star it will tug on the star a slight amount and force it to move back and forth as the planet orbits around the star. The bigger and closer the planet the larger the amount of movement in the star. Right now we could detect Jupiter around a star, but we'd have to observe the star (not continuously fortunately, just intermittently) for at least an entire orbit: 12 years. Also, if the relative angle of the orbit is nearly perpendicular to our line of sight then the motions of the star will be up/down and left/right instead of back/forward so we won't be able to see them with the radial velocity technique, and with the current level of sensitivity of such instruments that translates into roughly 10-20% of the potential orbital inclinations. **tl;dr** There's about a 90% chance we'd be able to detect Jupiter, though it would take at least a decade of observations, and there's about a 0.3% chance we'd be able to detect Venus or Earth. Although the technology is improving fairly rapidly so what we'll be able to detect in another decade will likely be different.
10
[Zombies] In modern stories where zombies/walkers are treated like purely scientific carnivorous animals, why aren't the zombies all starving to death within a year because their prey is being driven extinct?
48
This happens in 28 Days/Weeks Later. Humanity still ends up ruined, but the zombies do starve given enough time. Humans take weeks to starve, records are pretty sketchy here as most of the "longest without eating" claims are religious figures claiming supernatural assistance. Lets say 45 days is the limit with no food. Zombies don't sleep, so lets assume the disperse radially from the center of the outbreak. 5 kph is the average walking speed, 24 hr per day times 5 kph times 45 days gives us 5400 km. Lets round down to 5000km for meandering. That's how far a zombie could travel with no food. For reference, NYC to LA is ~4400km, well within that range. So draw a 5000 km circle around a city you want to say is infected and the draw 5000 km circles around every circle population center in that circle. You'll quickly see that the barrier to zombies isn't starvation, it's just oceans and us killing them. You could hide. Find a bunker, wait 6-8 months. Keep in mind though, that every new infection basically resets your timer for when all zombies will have starved by 45 days. You could be in that bunker a very long time.
55
[Dc] Why is constantine tolerated in the justice league?
His main character point is he is untrustworthy and backstabs and tricks everyone, so why is he allowed to be in the justice league or the justice league dark?
87
Because he is a master magician and expert on demonic magic that is an invaluable ally. Keep in mind, that doesn't mean he's completely tolerated - his ex Zatarra can barely tolerate his presence >!due to his involvement in her father's death!< and he's been kicked off Justice League Dark at least once because of his obsession towards her; >!one case was himself doing so since it put the others in danger.!< Edit: Also, he's treated as untrustworthy who betrays people to their doom, but often it's because they're already damned beyond saving which he kicks himself over.
78
[Harry Potter] What's the point of the sorting hat if it puts you in the house you want anyway?
Like can't they just let the kids pick which house they want in a secret vote or something so they don't get peer pressured? Also, how did the hat start talking? Like is it an actual wizard that was trapped in the hat, did Dumbledore create it himself or did he just find it already talking?
357
The hat doesn't put you in the house you personally want to be in, after all, Hermione had more of a preference for Ravenclaw before she was sorted. What it does do is look into your heart to see what kind of a person you are. Harry's desire to not be in Slytherin showed the hat that despite Harry's great potential to use the traits associated with Slytherin, he didn't want to be that kind of person. It was that selflessness of preferring to be a good person than a successful one that told the hat that he deserved to be part of Gryffindor. As for how the hat started talking, the legend goes that when the founding wizards of Hogwarts decided to split the school into the houses, Godric Gryffindor enchanted his hat to do the sorting based on the criteria the founders set, and it sorted new students ever since.
360
[The Expanse] How is Mars able to stand any sort of chance against Earth?
Earth has several billions of people, and the economy that comes with that. I don’t know what the population of Mars is, but if they have to live in habitats, it can’t come close to Earth’s. There just isn’t enough collective physical and mental manpower on Mars to keep up with Earth both logistically and technologically.
40
Earth has a population of 30 billion, however most of the population lives on "basic" assistance, essentially struggling below the poverty line. Mars has a population of 9 billion and their entire culture is near militarized towards their goal of terraforming the planet - they look upon the people of Earth as weak, suckling off of basic and living weak and papered lives compared to the struggle they endure. Earth actually lags behind Mars technologically, in the early days all the best scientists, industrialists and entrepreneurs went to Mars. Earth has more ships, but they're older and far less advanced, case in point, a state of the art Martian Corvette was able to cripple an Earth Battleship. But dem dusters and dirters down da well got noting on Beltalowda.
75
Are there any philosophers who speak about the preference of death over an afterlife?
Has there been any philosophers who have objected to the heaven/hell dichotomy preferring eternal destruction of the self over a continued existence in another realm?
59
In Plato's *Apology*, Socrates argues that we have nothing to fear from death because both an afterlife and oblivion are desirable states. Schopenhauer, taking a cue from Indian philosophy and religion, believes both in a cycle of endless reincarnation and that this process of reincarnation is a bad thing; he sometimes explicitly describes the end result of the process of escaping this cycle, which he holds as the highest ethical and philosophical goal, as if it were the literal cessation of all existence. But he's very ambiguous about this, and eventually goes on to say that we can only really be sure that this cessation would be "nothingness" relative to the perspective we have while we are here trapped in the cycle.
29
ELI5:Is there a specific reason why our forearms and calves have two bones instead of one?
16
It allows them to rotate axially, for example turning your hands from palm down to palm up. Imagine you had one big bone in your forearm - how the heck would that work? You would have to twist the bone itself, and spiral fractures are no fun. Instead, the two bones just shift around each other.
22
[Star Wars] How can one rogue apprentice destroy all the new Jedi with Luke Skywalker being around?
36
By being the apprentice Luke loved best. Ben Solo was Luke's nephew. Luke would have known him from the day he was born. With no family of his own, Luke would have loved him like his own son. When Ben turned on Luke, it would have been shattering. Heart-breaking. Luke would have hesitated. He would have tried to talk. He would have tried to beg. He would have done anything he could think of to stave off the moment when he would have to kill his own nephew. And then, by the time he realised he was out of options, it was too late.
61
[WH40K] There is enough evidence to convince the Imperium beyond reasonable doubt that the EoM would come back within a millenia if the Golden Throne were destroyed. Would they be able to afford to do this?
If they go through with it, what's the holding pattern while Big E regenerates/reincarnates and makes himself known again?
50
No, the Imperium can't afford even minute interruption in the work of Astronomicon beacon, let alone millenia, and God-Emperor and his Golden Throne are integral parts of the beacon. Without it, Astronomicon would go out and ships won't be able to safely navigate the Warp, basically starting another dark age and needing to reconquer everything all over again. There's nothing short of Plot Induced Stupidity that can convince High Lords of Terra to take God Emperor off life support, and Lord Guilliman would probably slap your head off if you suggest it in his presence.
64
CMV: mocking or distorting academic meaning of important terms is heavily contributing to post truth world we live in
I see all the time people completely disregarding what important concepts actually mean and putting popular understanding (many times shaped as propaganda) as a more valid definition. Good example is happening in CMV right now in discussing USSR where word communism is used a lot. Popular mocking phrase in USA/internet/reddit is - "not real communism" (usually with weird caps) when people try to say that USSR doesn't represent it. The thing is... Even the county itself was called Socialist. By definition of Government type/Economic system it was Totalitarian/ central planning socialism or even central planning state capitalism. By no definition of communism was Soviet Union even close to it or try to claim to be. Communist Russia was literally invented as a propaganda name and yet people still seem to mock anyone who points out the flaw of directly linking the two. There are many more examples like this, like US definitely not being a free market economy or whataboutism being frequently confused with precedent (one is an unrelated point to deflect blame, other is a related/equivalent action brought as an example). Or my favorite "just a theory" said by people who clearly try to mean hypothesis from context. Using incorrect or pop understanding of words instead of academic meaning on important subjects is detrimental to discussions.
20
On the issue of the USSR "not being communism" because they called themselves socialist... you have to be very careful about taking a country at its own word about what it says it is, versus how it actually functions in practise. For example; North Korea calls itself "The People's Republic of Korea". So, taken at face value we must assume that N.Korea is a wonderfully democratic republic system, yes? Well, obviously not, it's an authoritarian hereditary dictatorship. Another example; Germany in the 1940's was run by the "National Socialist Party", but was far from truly socialist and in fact persecuted and hated socialists particularly Marxists and Leninists, they hated and rejected the idea of social welfare instead believing in social darwinism (e.g. life unworthy of life), banned trade unions...; so in reality Nazi Germany was just another form of Fascist Dictatorship. Examining the USSR under Stalin in particular, it was certainly a corrupt communist dictatorship. Wealth and property was owned and dictated by the State not the People, wealth was seized and redistributed (often in a corrupt manner), and the the economy (particularly manufacturing sectors) were nationalised in pushes for industrial revolution to compete with the West during the Cold War. *Also, if we are going to take them at face value- the ruling political party of Russia from the early 1900's through to the dissolution of the USSR in the 90's was the CPSU (Communist Party of the Soviet Union).*
12
ELI5: when you buy bananas that are green and not ripe, how do they become ripe and yellow when they are not getting any nutrients from the tree but just sitting in your house
84
Bananas do not ripe due to nutrients they get from the tree ....instead bananas release a gas called ethylene from their stems which make them ripen .... not only bananas ...ethylene can ripen other fruits too if you keep them close to the bananas .
97
CMV: Cancelling student debt seems like a terrible idea
Obviously, student debt is a huge issue for many Americans who are stuck managing it for years if not decades but I feel like the core of the issue can solved in so many other ways other than cancelling the debt as a whole and that taking this route would not only be unnecessary but also unfair. Why are we so hyper focused on student debt cancellation when the core of the issue comes from uncontrolled tuition and rent increases. If anything, cancelling student debt just signals that these institutions can do whatever they want on that front with no fear. On top of that coming from a poor family growing up in an upper middle class region. The majority of people I saw taking up student debt absolutely took on more than they needed to. I graduated from a class of around 1,000 people. Of those 1,000 people around 80% of them went for higher education, yet only 50 of them went to state university. I knew people that were in hundreds of thousands of dollars of debt for shit like an English major. My family worked hard to get to where we are, my parents never had any luxuries, the amount of times we ate out can be counted on one hand. Despite that I still commuted and worked every year from HS to college. My parents don’t have much but they’re proud that they were able to provide that for us. The idea that someone else can just be handed that when 1, they could’ve avoided more than half of the debt they took on and 2, didn’t nearly sacrifice as much is bullshit.
23
I imagine that most people who want student debt cancellation also want the increased price of education to go away, either via free college or something else. Also, "I suffered so other people should suffer too' is the worst reason to write laws.
37
[MCU] How does Captain America age?
He goes into the ice and comes out without aging a single bit. Then he gets sent back in time and seemingly aged normally, him being an old man at the end of Endgame. Does he age slowly because of the super serum?
16
He was 39 when he went back in time, if we assume he went back to that point at the end of WWII (1945) and lived till Endgame in (assuming 2019), he'd be 113. It's not an impossible age for a normal human, he was just very healthy for his age due to the super soldier serum, probably a couple decades younger physically compared to his real age.
30
Why is escape velocity so high?
Why is the escape velocity for earth 11.2 km/s? Can someone explain why it needs to be such a high speed? Why can't a vehicle just travel at a steady 1 km/h until is out of reach of the planet's gravity?
39
It can, it would just need to be thrusting the whole time. Escape velocity is the speed you need to escape without adding any more energy - just coasting. That is why escape velocity depends on altitude - the higher up you are, the less speed you need to go the rest of the way.
86
[Jessica Jones] How does Jessica Jones' abilities rank in the Marvel Cinematic Universe?
It appears to me that she probably wouldn't survive against a well-trained SHIELD agent or any super-powered humans in the MCU except for some of the Inhumans. Like she is clearly not bulletproof and can't dodge bullets any more than the average person. What sort of level of strength does she have? They do show her half lifting a car and picking up a huge porcelain sink with one hand as well as breaking locks. Has she been holding back on her strength? Also is it clear that she can properly fly? There was only one scene where it seemed like she did fly but it was kind of off screen. Otherwise they just show her making huge jumps. Like it seems that there are normal humans that have far better natural abilities. Examples of which are Natasha Romanov, Clint Barton, or Grant Ward (who seems so overpowered). I love her character so much but it seems like they didn't really portray her abilities as being particularly impressive.
200
Jessica is strong but she's entirely untrained. That's why she struggles sometimes fighting multiple people, she punches badly and throws people. She has no idea how to really fight properly. Someone like Cap would utterly destroy her in a brawl (Cap with his shield could more than likely beat Luke Cage even though). She's probably a 1-2 tonner at her max. She only lifts up the back of the car which some very strong people can do. She's still very durable and can likely fly if she learns how. If she was trained how to fight and use her powers more effectively she'd be a force to be reckoned with for sure. But right now she's low street tier.
214
[Arrival] Why doesn't Ian learn the heptapod language as well so he can see his daughter?
We're told the reason Ian eventually leaves Louise is because she gives birth to their daughter despite knowing she is going to die. This is made worse by the fact that while Louise has the ability to go back and "visit" her daughter in a sense, Ian can't as he doesn't seem to know the language in the future. My question is why not? He worked on the language right alongside Louise, and his wife even wrote a book teaching people about the language. Shouldn't he be able to see time non-linearly too and know the truth about Hannah?
25
It's not just that she learned the language, but that she became so deeply involved in it that it changed the way her brain processed the world around her. The short story goes into this phenomenon more, setting it up with examples like a culture that doesn't use relative directions (left, right, etc), only absolute (North, South, East, West), and as a result, seem to have an innate awareness of those cardinal directions. But it's not from simply learning the words of the language, but from the way the language requires you to think.
40
Does the Wharton salary question have greater implications?
Academics spend their lives working in higher education and are often times quite comfortable and surrounded by other like minded academics their whole lives. The recent [Warton salary ](https://www.phillyvoice.com/penn-wharton-professor-nina-strohminger-viral-tweet-average-american-salary/)question may show how out of touch students in business school are about income. Maybe this principle applies to those in other fields of study. I study computer security, for example. I do not feel my peers appreciate how completely unconcerned most users *will always be* with regard to the inner workings of computers and computer security principles. Specifically, there is an expectation that an individual user monitor their credit account activity for suspicious activity when, in fact, compromised accounts are typically the result of an institutional security failure. We do not ask bank customers to take turns guarding the door or monitoring security cameras and we should not. As an academic in your field of study, what fundamental things do your peers seem out of touch with?
64
The answer by those Wharton kids has more to do with the fact that UPenn has more people from the top 1% than the bottom 20% and rich kids don't understand the privilege. Plus the median income of the family of someone who goes to UPenn happens to be above 100k, so the answer reflects the students' immediate bubble. It is out of touch with reality, but for reasons of rich privilege rather than academic ivory tower.
99
[Star Wars]Why does C3P0 refer to R2D2 as his "counterpart"?
Is it standard for droids to have a partner droid?
233
Droids that work together on a regular basis can, over time, become so accustomed to each other that they are considered counterparts. They essentially both develop code that forms a kind of "shortcut" when they're interacting, letting them function together much faster than normal droids can. They can also use that code to develop complex encryption codes that are virtually impossible to break for anyone but their counterpart.
196
[LoTR] What if Morgoth and not Sauron had been the one to have the idea to create the One Ring and vest the majority of his power into it as Sauron had done?
32
Morgoth *did* in a sense create a Ring of Power. Tolkien says that because Morgoth invested so much of himself into corrupting the material world, *the world itself was his ring*. Hence the name of Morgoth's Ring, one of the books of the History of Middle Earth. Because of this investiture, his power over the physical world was greatest than all beings, though eventually he squandered so much of his influence he was severely diminished. Still, it was this Morgoth-element that polluted everything which allowed foulness like necromancy to work. In more prosaic terms though, the Rings of Power were a plot by Sauron to make the Elves enslave themselves to him. He would teach them to make these amazing rings with the power to slow down decay (the thing the Elves were most interested in, as they wanted to preserve the fading primeval beauty of the world), but secretly there would be a backdoor that would allow him to control all Ringbearers through the One Ring. It wouldn't really make sense for Morgoth to attempt something like this. He was at open war with the Elves from the start and couldn't take a fair form like Sauron did, so he could scarcely trick them the same way. He also didn't care to dominate, he wanted to destroy: when he took over an elven kingdom he had it sacked and burned, its prisoners taken for slaves to toil in Angband; he didn't want to govern anything, just ruin it.
48
[Star Trek] Why are the Borg so dangerous?
I have a question about the Borg, why are the Borg so terrifying and dangerous? Is it possible to defeat the Borg?
38
They're dangerous because they have an overriding directive to assimilate other species' technology and biology into the collective. If you resist being assimilated, you're an enemy. Also, they are hard to fight because they can alter their technology on the fly to counter nearly any kind of weapons, armor, or shields they encounter.
42
ELI5: What is meant by right-wing & left-wing in politics?
2,885
So the actual origin of the term goes back to the French Revolution where people who supported the revolution literally hung out on the left side of the room while supporters of the king hung out on the right side of the room. So the left wing was the more liberal side of the group as a whole so now any group that really does want to do something "new" is probably going to be called "left wing". Meanwhile a more conservative group that either doesn't want to change or maybe wants to change back to the old way of doing things is going to be called right wing.
4,481
ELI5: Why can a company fire an employee for a Facebook comment, but not sue a non-employee for defamation because of a Facebook comment?
69
The standards are different. In the overwhelming majority of cases, an employee is "at will." This means that the employer can fire them for any reason or for no reason at all. In the present day there are some restrictions on this---you can't fire someone because of their religion, for instance---but very few. Thus, posting something on facebook can get you fired, but so can not posting something, or posting the wrong thing, or any other thing that the employer doesn't like. A lawsuit for defamation is very different. Here, you're not dealing with the employer's decision to keep someone on the business's payroll, but with the employer's desire to use the courts to get something. In the U.S. at least, the standards for defamation are very, very hard to meet. As such, very few of these cases are filed. As a note, though, this is not any different than suing an employee. You can fire the employee for their facebook post, but unless you met that same high burden, it would not be any easier to sue the employee for defamation than it would be to sue the third party.
25
Do straight lines exist?
Seeing so many extreme microscope photos makes me wonder. At huge zoom factors I am always amazed at the surface area of things which we feel are smooth. The texture is so crumbly and imperfect. eg this hypodermic needle http://www.rsdaniel.com/HTMs%20for%20Categories/Publications/EMs/EMsTN2/Hypodermic.htm With that in mind a) do straight lines exist or are they just an illusion? b) how can you prove them? Edit: many thanks for all the replies very interesting.
359
Not in the sense you have in mind. Even atomically smooth surfaces are bumpy at the atomic scale. Straight lines (and smooth surfaces) are mathematical constructs that provide useful approximations to reality in many situations.
315
Are you at greater risk of sunburn up on a mountain?
I remember being told that sunburns are more likely when you're up in the mountains because the air is thinner. And that's why Andean peoples wear wide brim hats most of the time. And I think my own experience matches that. I've burnt pretty quickly when up in mountainous terrain. But I also know (believe) that UV is mostly blocked by the ozone layer. And the ozone layer goes from 33,000 feet to 165,000 feet. So even on top of Everest you're fully under it. So it shouldn't matter how high you walk. You should still be protected. So what's going on? Which part of what I think I know is wrong?
59
The ultraviolet spectrum is pretty broad (400 nm – 10 nm) and is divided into three sub-bands. Ozone is really good at absorbing the short UV-C wavelengths and moderately good at absorbing the medium UV-B wavelengths. UV-A and UV-B (which are responsible for sunburns and skin cancer) are mostly absorbed by water vapor and other atmospheric gases, which is why being at sealevel offers more protection than on a mountain.
50
ELI5:What makes a tree live on, while plants such as corn die off quickly?If a tree grows on and on without disturbance,is there a limit to its lifetime?
379
#Slow and steady vs. Fast and furious The main difference is how each handles reproductive events. Reproduction is the most energy and resource consuming event any organism can live. Herbs (what you would call "plants") have chosen the strategy of tanking stressful environment as a seed or tubercule, gather resources during the favourable weather and use all their resources in a single reproductive event, this killing then because they don't have any more resources to keep themselves alive. On the other hand, trees have chosen the strategy to slowly gather resources, even during stressful conditions (like bad weather) and use only a fraction of their resources in each reproductive event, meaning they keep some resources to themselves, letting them stay alive. Neither strategy is inherently better than the other, they're just different ways of solving the same problem. --- --- #How to live forever You might have seen that after cutting the main trunk of a tree, little branches grow back, ultimately making a new tree again. This is due a "stem cell like" property of trees, where they always retain their merismatic cells (the equivalent to stem cells in plants) after each growing event which grants trees with the ability to regrow or repair any organ. If met with theoretical ideal conditions (always good season, no predation, no competetition), you can argue that a tree can live forever. The next challenge comes from within the cells of the tree. Just like humans, trees have chromosomes (which are may bundles is compacted DNA), at their end they have a strand of DNA known as telomer. Each replication event of the cell shortens the telomer. When there's no more telomer left, the cell dies. So, unless you have a way to repair that telomer loss, your days as a tree are counted. Some trees, like some types of pines, have the ability to repair that loss with an enzyme that "rebuilds" the telomer after some replication events, thus, granting the tree with eternal life. --- --- #Could this actually happen? The dynamic nature of Earth and its ecosystems represents a huge challenge to any organism that aims for eternal life. You have catastrophic events that are cyclic, some unpredictable bad seasons, constant competition with other organisms like you, constant predation and parasitation, internal mistakes (trees can get cancer too!) and such. The oldest trees we know are around 5000 years old, although a whole lot of time, it's just a moment in the history of Earth.
331
ELI5 why is it that you can break a piece of a tooth and it doesn’t need fixing, but if you have the tiniest cavity it has to get filled ASAP?
1,878
A cavity is decay-it is dead and dying areas with bacteria, and can spread if not taken care of. A cracked broken piece of tooth, depending on how deep the break is, won't cause increasing problems over time.
1,076
[Warhammer 40K] Can you boost the collective intelligence of the Orks by telling them books make you more killy?
32
I mean, "collectively" orks are already as smart as any other space faring race. They've collectively got the knowledge to build spaceships and other technology on par with anyone else. Besides, most orks can't read, so not like books are gonna do much besides get thrown around or lit on fire.
36
ELI5: What is quantitative easing?
29
Quantitative easing is a tactic used by a country’s central bank (eg. The federal reserve) to add money to the country’s economy, primarily in times when the economy is slow or have collapsed. Because the central bank cannot give away money for free, it makes large purchases of government bonds or financial assets(Billions of dollars worth of assets). Once the bonds are purchased, the money is then used to fulfill the purpose of the bond (build roads, develop systems etc). This now means that people will be hired to build the roads, materials will be bought and so forth, so that money will now be circulated in the economy thanks to quantitative easing.
10
ELI5 how does freeing up storage space make your computer faster?
24
In general, it doesn't. If your hard drive is almost completely full then it can have an impact. Your operating system may temporarily dump some of the values it's tracking in RAM to your hard drive to make use of RAM for something else to speed things up. If there's not enough space on the drive to do that, it could affect performance. If you have 1 tb drive and go from using 700 gb to 500 gb it won't make a difference with respect to performance, though.
60
If a woman doesn't get her period and is not pregnant, what happens to the eggs?
For example, taking contraceptives that may stop a woman from getting a regular period.
54
Nothing happens to them. When a baby girl is born, she already has all the eggs she will have for her whole life in her ovaries. If she doesn't menstruate on any given month, it just means no egg(s) exited her ovaries.
17
ELI5: How the Credit Card Competition Act works and why it could mean no more credit card rewards programs
39
The general idea is that right now, merchants pay money on every credit card transaction in their store. With this new act, the government wants to try to drive the cost of that fee down. But if they do that, then credit card companies might reduce or even cut out some reward benefits because they themselves would be earning less money. So the act does not say or do anything about rewards programs specifically. But if the credit card company ends up making less money, then they are less likely to keep giving money back to customers in the form of rewards.
84
ELI5:What are the strings in String Theory made of?
17
They're made of strings. In string theory, the strings are the most fundamental object in the universe, so they can't consist of anything else. It's like asking what an electron is made of, it's nonsense because (as far as we know) electrons are just electrons.
11
[General] If the multiverse has every possible outcome in all existences, and it is possible to travel between universes in it, shouldn't every universe be filled with multiverse travelers everywhere?
61
There would be infinite travelers, so there would be universes full of them. There would also be infinite universes that had none. And infinite universes that never spawned them. By definition, one possible outcome is a universe with just one traveler. And another with just two. And another with just two but they're slightly to the left. And one where you are the first to go there, or others leave exactly as you arrive. Or one where an infinite number of travelers arrive at exactly the same time, instantly filling all space and collapsing that entire universe into a black hole.
75
[Disney's the Little Mermaid] King Triton is extremely powerful. Why can't he destroy the contract Ariel signed? How is it protected?
Ursula says something about the contract being legally binding, but what does that actually mean in the context of an absolute monarchy in a magical environment?
141
The magic of the sea is old and strong, and of all magics the binding power of a contract is one of the oldest and strongest, especially a contact agreed to by royalty. King Triton is strong, but even he cannot breach the foundations of the magic of the sea
107
CMV: Human Resources is the laziest and biggest drag to a company's bottom line
Background: I'm a Director level professional with 30 years in my field. I have two certifications, one of them being the top in my field. I've worked at both corporate and non-corporate levels, both franchisor and franchisee sides of my business. I've had roles where I supervised employees and roles that I did not. I've also had positions where I was responsible for a budget and others where I was not. Anyone in the know realizes that HR is for the company and its benefit, not for the employees. I get that. I feel that in *most (not all)* cases, though, employee law is pretty cut and dried. You can't mistreat employees, You treat everyone equally. You can't discriminate on the various protected classes. If you need to fire someone, you build a case in writing, document conversations, set expectations, etc. Aside from this, you have benefits management. Someone needs to be an expert at insurance, etc. and knows how to manage what comes with that. Other than that, HR is just a drag on the bottom line. They don't produce anything. All they really do is keep supervisors from making emotional and dumb personnel decisions. Often, their advice can hurt future business if they don't allow someone that is hurting the company in terms of bad customer service to be let go, in order to save a few UI dollars. They even usually allow bad managers with bad leadership skills to make calls that while certainly legal, actually hurt the business and it's bottom line, over the long term. We also know what happens to good employees that see bad employees not held accountable. Then there's the lazy part. They use questionable systems that sort through resumes that have the potential to eliminate excellent employees, based on arbitrary criteria. Even worse, these systems can't really offer an accurate assessment of the resume. I just got the results back from a service that reviews resumes. He ran it through one of these Applicant Tracking Systems, ripped it apart and told me what every article of this subject matter tells you. The usual "too many bullet points, not enough accomplishments, etc." Okay, well you want 4 bullet points for a job that will require at least 60 hours a week and the job description has 15 bullet points. How the hell am I supposed to get this down to 4 bullet points when it's obvious the job calls for SO much more? And I have to guess which ones are most important to you! When did applying for a job become such an exercise in playing mind games and jumping through hoops *just to get an interview*? You only want a two page resume, and you don't want to take the time to even look at that. As for accomplishments, how many do you need? I gave a few, but if all you want are accomplishments to brag about, again, do you want an accurate depiction of what I did or not? Not every job is saving the company a billion dollars allowing more people to be laid off because of my awesome efficiency skills. Sometimes, the job is just doing the job and making your customers happy! THEN it says it thinks that I'm best suited for sales and marketing by 52%. WTF??? It's ALL Operations! I hate sales and marketing! How do you get this out of what's on my resume??? No fucking wonder I can't get an interview! But wait, there's more! Then it says I have 12 years of experience (out of 30) and gives me a Management Score of 55/100, based solely on job title. Well 10 of those (12!!!) years was a general manager!! Three out of the four job titles have "Manager" in the title!! How does a system so important get this so wrong???? [https://www.theverge.com/2021/9/6/22659225/automated-hiring-software-rejecting-viable-candidates-harvard-business-school](https://www.theverge.com/2021/9/6/22659225/automated-hiring-software-rejecting-viable-candidates-harvard-business-school) They say this is to save time, because they get hundreds of resumes for a job posting. I have no doubt that it saves time. But I call bullshit that this is why these systems are used. They are used because HR doesn't want to put in the effort to find the best candidate for the job. It takes time and effort, and people, by nature, want to put in the least amount of effort. As I already stated, I'm a 30 year professional at mid-level (Director). My experience and background is more varied and more solid than the vast majority of bosses I've had of the past 15 years. During this time period, it has been a bitch, and I mean a bitch, to even get a fucking interview, much less an actual offer. This isn't due to dumb shit like grammatical and punctuation errors or applying for jobs that I'm not qualified for. I've applied for jobs that were almost exactly like the job I have/had. Still, nothing. All HR is used for in this process is as a filter, to get the good candidates in front of the people that do the real interviewing and make the real decisions. But yet, HR can't get even look at what could be excellent resumes at least worth talking to. They somehow don't have the time to fill job positions. Seems like a pretty basic function of HR to me. Now maybe someone looking at this post is thinking "Well he has a terrible attitude, I wouldn't hire him either." That's not the problem! The problem is getting interviews, not getting job offers. There is nothing in negative tone in my resume or cover letter. It's actually quite the opposite. If you had told me 20 years ago that I would have the level of experience I do and have to beg, plead, and lie to get an interview, I'd have said no way, there's something else going on here. What's going on is it's impossible to get a good resume in front of people, because those gatekeepers can't be bothered to find the best candidate for the job. They're much more interested in filling the job with as little effort as possible even if it isn't the best applicant. CMV!
25
The flip side is that lawsuits can be very expensive & potentially a PR nightmare, so HR is the price companies pay to try and make sure they can prove in court they crossed all the t’s and dotted all the i’s.
16
ELI5: Why do animal brains tend to operate far more efficiently than even the best computers?
Brains occupy a low volume and use very little energy compared to computers. How is this possible? What's preventing computers from becoming more efficient than the brain?
15
What makes you think they are less efficient? Computers are vastly more efficient than brains, at some tasks. Running a modern game requires billions of floating point calculations per second. Even if you drafted the entire population of the planet you couldn't get that kind of throughput. We win at other tasks like path finding, but not by much any more.
15
CMV: On social media, more people should attack bad ideas/posts from people from their own tribe
Couple of semantics to get out of the way. 1. By social media, I am talking about forums/websites such as facebook, twitter, reddit where people exchange ideas and debate about different topics. I am hoping that this CMV does not devolve down to arguing over what is and what isn't social media. 2. By "attack bad ideas/posts", I am referring to the act of vehemently arguing against the person/post in question while being level-headed and abiding by the proper decorum of public discourse. 3. By "tribe", I am referring to common groupings that people use for certain conversations. For example, when it comes to US political debates, this might be Democrats vs Republicans. When it comes to certain religion debates, this might be atheists vs Christians. As such, an example of attacking people from their own tribe online would be a liberal attacking a fellow liberal who makes a bad post (or conservative attacking a fellow conservative). \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ So with the semantics out of the way, let's get to the point. When it comes to important debates and topics (e.g. police violence in the US), there are usually two groups of people who come in contact virtually (e.g. in this case, liberals and conservatives), and heated argument pursues. Inevitably, there are various different types of people jumping in on the debate from both sides. What is commonly observed in these online debates is that bad arguments and intellectually dishonest posts made by someone from some group A are usually only attacked by people from some other group B. It is rarely the case that people from group A attack their own when it comes to bad arguments/posts (now, for the CMV, we can discuss whether my observation is true, and I would be ready to reconsider on frequently this occurs). In many of the cases, the smart people just ignore these bad posts from their own side and attack the other side. Now, I am not saying that this is necessarily wrong and I think there is a good argument to be had on why one should be tribal (e.g. need to focus on winning the war of ideas). But I am thinking that it might be healthy if people who are pretty level-headed and intelligent about certain topics actually attack these bad posts from people on their own sides. The main reason being as follows. (1) Truth and intellectual honesty matters. Many times, these fringe people from our own sides resort to dirty tactics, distortion of facts, strawman tactics to attack the other side. And I believe that there needs to be some sort of base level agreement amongst the majority that this should not be tolerated regardless of the said person is on our own side or some other side. And it doesn't take too much of an effort to point this out if you are a power user (e.g. "I am actually in group A but here, your data is wrong, and you should consider editing your post."). It only takes 2-3 seconds to type that up. (2) Attacking bad ideas would demotivate these fringe people. In social media, I would not be surprised if there is a certain level of confidence instilled in these posters knowing that roughly 50% of the people will "back them up" due to the tribalism. As such, there is not much of a social penalty of being shunned by 80-90% of the people in a given forum for creating bad posts. However, if it were the case that people attacked bad ideas from their own group, then I suspect that people would be more careful about making good/bad arguments. This would clean up the conversations quite a bit as a good filter will be in place to penalize/criticize bad ideas. (3) Negative feedback loop that leads to more tribalism would be reduced. Sometimes, I think people overrestimate the degree in which there are extreme voices amongst different groups. When I talk to people in real life, most are normal people who can have a healthy conversation. However, when we view social media, the bad actors from both groups get amplified and even the average person (due to the amplification) might think that there is much more dissent amongst the groups. This leads to a nasty feedback loop that leads to more dissent as people think that the disagreement is much more heated than what is actual. By nipping the bad actors initially, it would cool down the conversation and reduce the unnecessary temperature rise in conversation. Conclusion: rarely is the case that smart/level-headed people attack posts/people from their "own side" when it comes to online discourses. This should be encouraged as there are benefits to it (my points (1), (2), and (3)).
134
Let's view this from a game theory perspective. If your group does this, and the other group does not, you could run the risk of the other group abusing this by driving a wedge between the sub-group, making your group splinters, and weaker. A temporary example would be Russia, China, and Iran, using online trolls to exacerbate the current situation. Or in a 2 party system, if one party is more united than the other, the more united party could take a more moderate stance, to absorb more moderate voters from the opposing party, without risking losing their fringe voters. This is most successful in divide and conquer, divide the opposing group into sub-groups and make the sub-groups fight one another, just like in in colonialism.
18
ELI5: In a few billion years when the sun expands and grows into a red giant, how fast will it expand and "swallow" the inner planets?
187
The sun is expected to last another 5.4 billion years before the hydrogen in the core runs out. When that happens, the core will start to collapse in on itself due to its own gravity, and will increase in temperature. This allows for hydrogen fusion outside the core to happen (the strong temperature gradient doesn’t allow the layers outside the core to mix with the core and supply more hydrogen to maintain it; the core needs to grow in size for the next step) This is when the sun enters the subgiant phase. In the subgiant phase, the core is having a battle with itself. On one hand, it’s so dense and heavy that it wants to collapse in on itself. But at the same time, it’s way too hot to make that possible (heat makes atoms move faster, so it’s harder to get them to collect at a single point). At this point, the core gets so hot, that even outside the core it gets hot enough for hydrogen to fuse. Hydrogen that fuses turns into heavier helium which then grows the core a little again (the boundary of the core isn’t very exact). The energy that’s produced in this process pushes the outer shells of the sun farther out. The sun grows to roughly three times it size, becomes a little dimmer as the same amount of energy is spread out over a larger outer surface to radiate off. This is called the subgiant state and this state lasts for about 2 billion years for our sun. After the sun has been a subgiant for a good long while, suddenly an event happens: the core does no longer contract. This is called core degeneracy. At this point, the repulsive force of the electrons around the helium nuclei give enough backpressure that gravity can no longer collapse the core any further. So now all the energy being fused around the edge of the core can’t go anywhere, what now? The sun starts to grow in size tremendously, growing to 100x it’s current size. Lots of hydrogen is fused into helium at the edge of the core and a lot of energy is convected to the outer layers of the sun. The sun becomes a lot more luminous, too. This is the first red giant phase, and lasts about 100 million years. As the core continues to gain more mass, slowly but surely it eventually reaches a point where the core reaches 100 million Kelvin, at which the core finally can start back up again, fusing helium into carbon. This happens in an impressive explosive called the helium flash. In a matter of minutes, most helium in the core is converted into carbon, releasing a tremendous amount of energy. Because of this energy, gravity is overcome and the core expands again. The star decreases in size to around 10 times the size it is today in a very short period and it stays this way for about 50 million more years, while it fuses helium into carbon in the core. When the helium is all used up and the entire core is made of carbon, the core once again goes into hibernation and something like the earlier red giant phase happens again. The core starts to collapse again and becomes hotter. Now there are two layers around the core, the inner layer is so hot that helium is fused into carbon, and the outer layer is fusing hydrogen into helium again. As this happens, a lot of energy is produced that’s not going in the core, but is used to expand the sun again. The sun now finally enters the real red giant phase, in which it grows to about 250x it’s size today. This is the point where the Earth may very well be taken up by our sun. This phase lasts about 20 million more years, in which the instability of the sun will make the sun pulsate, throwing off enormous amounts of its outer shell material until finally, the hot carbon core becomes visible, at which point we consider the sun to no longer be a red giant, but a white dwarf. The white dwarf is still tremendously hot and it radiates a lot of high energy UV light. This UV light pushes and illuminates the old outer shell that’s veered off into space, and that creates a planetary nebula. So, when and how fast will the planets be consumed? Mercury should be seriously concerned in the first growth. That’s in about 7.4 billion years. We have another 150 million years roughly until we’re finally taken into the outer edges of our sun. Which is really no time at all in astronomic terms. Better enjoy the sun the way it is today while it lasts.
162
ELI5: What causes blood to randomly rush to the penis, causing a random erection?
25
It’s not a random rush at all. Many times during the day your autonomous nervous system reacts without you consciously having to think about it - you breathe autonomously, you get hiccups autonomously, your intestines are told to move autonomously etc. Similarly, a stimulus you’re not even aware of might trigger the reaction. Or a “system check” happens - nerves that lead to you pelvic area are active and relax muscles that among other things control blood flow in your penis
19
My manipulative professor
I have been manipulated by my professor for about 2 years now. He always threatens me with my scholarship. He knows I can’t afford living without it. He denies me basic PhD merit like having my own study, using our lab’s databank or even attending conferences. He always like to put his name first on all papers and he likes to suck up to the dean and put his name last. So basically, despite how much I put into my research, he will always be first author. I only get salami sliced data or remnants from other studies to work on. So basically, I cant publish in high impact factor journals. I went to the harassment center in my university but they told me that they can report this incident, however no one can protect me, even the university itself. I really am stuck and don't know what to do. I don't know if I should continue sucking it up or quit or what. I have nowhere to go. My colleagues warned me about him when I came to this lab but I didn't understand what they meant at the time. All of them are leaving him as soon as they finish working with him, but I can’t wait that long. I still have 2 more years. I need to find a way to cope with this. Please advise! If anyone has experienced dealing with a professor that is dark and manipulative, please let me know about your experience. *Edit: All I am asking for is an advice on coping or to hear from someone else's experience to learn from. I might be right or wrong, but what I know for sure is that in a PhD you shouldn't be suffering that much and that your professor should be your mentor not your nemesis!
24
Get out. Find somewhere else. Not necessarily in that order. You're not going to learn anything from this professor that will make you a better researcher, and they are not giving you the opportunities you should be getting.
42
ELI5: Why are everyone in '50s & '60s photos so thin?
33
In all seriousness, because people are fatter now. Children moved more in school, and we're much less likely to be driven to school, more likely to walk or ride a bicycle to school. Play was much more likely to be outside - no video games, no computers, no mobile devices. Oh, yeah, talking with friends? You gotta walk or bike over to their house. Children don't use the phone much in the 50's and 60's. Adults got much more exercise, too. Many more professions were physical, like manufacturing and such. But even daily life was much more physically demanding. No dishwashers, most food preparation was done by actual cooking, less by take-out, or pre-made stuff like Hot Pockets, or frozen pizza. Even activities like typing were more calorie-burning - modern keyboards require much less human energy than manual typewriters, especially if you had to punch each keystroke through three or four layers of carbon paper. No remote control for the TV set. And perhaps a little more somberly, we don't really realize how much easier it is to be in poverty today, in 2015, compared to the 1950's and 1960's. The biggest nutritional problem for the bottom 20% in the USA was finding enough food. Period. People were medically underweight because of malnutrition. They literally were so poor, that the couldn't buy enough *rice and beans* to get to a healthy weight. Today's main nutritional problem for the poor is obesity. That's how great our society has been the last 60 years.
72
CMV: Public exams in schools are relics of an outdated system and should be removed; they serve no useful purpose in preparing children for real life.
As children we are taught that we are essentially the same under the eye of authority, and that what determines one's worth is a number on a written assessment. Children are shown that it's the one that memorises information and retains it the best that achieves the most, or the one that can work under timed conditions. This type of erosion of the individual is not uncommon by the school system, but that is a whole different fish to fry. Exams create a very stressful experience and a negative view of education in children. The former is caused by timed conditions, an emphasis on memorisation \(which is a flawed mechanism, as no matter how much you study you will still forget something\) and a huge well of information taken from various sources, many of which children will have little to no care for \(the average student in England will take around 7\-11 GCSE subjects, many of which they drop immediately after they finish them\). This informational cramming is very stressful during a period which the child is developing into an adult, a time when they should be focusing on how to form relationships, meeting new people, finding new hobbies to enjoy. This starvation of free time and added stress has many knock\-on effects, namely addiction to smoking, video\-games and alcohol. Furthermore, education begins to be seen as a series of hurdles one has to jump over, where your worth is not determined by the sum of all your various qualities, talents and interests. Due to exams' incredibly narrow\-dimensional nature, only one or two qualities can be tested at one time. This would be fine \(given the 20\+ exams taken by students each year\), except some of these skills need to be developed over a long period of time, such as critical thinking and deriving conclusions from observation. Take physics, for example. Pupils are expected to know the bare minimum about electricity \(literally about three formulae\) in order to pass the electricity section of the exam. The most problem\-solving that is done is rearrangement of a formula. True understanding is not really needed, as the student who remembers the formulae and the students who remembers the formulae and understands the material will have scores that both put them on the same level of "problem solving and understanding", despite only one of the two truly understanding as a result. Students are thus dissuaded from "trying too hard", because the exam only demands so much from an individual and further knowledge is neither a necessity nor rewarded. Thus, being "good enough" is good enough, as far as the child sees. Essentially, there needs to be some reformation of the exam system, or it must be dissolved altogether. It squanders a child's development into an independent adult and sets up mental barriers and unrealistic expectations for the future, where the skills gained from exams are either not needed or fall short in light of much more important skills they could have gained, such as social skills and pursuit of individual interests. EDIT: Having read all your replies (which I must thank everyone for) and gotten a good night's sleep, my perspective has shifted. It's evident that exams have stuck around for so long for a reason, not just because we don't have anything better. It's also important that there is some sort of standardised testing, given the large variety in students across the country. However, I still believe that the structure of exams is flawed and definitely could use improvement, gravitating towards open-book exams where appropriate, and perhaps downscaling the volume of knowledge required per exam. Following a coursework structure could also be a step in the right direction. Nevertheless, consider my view changed.
31
Allow me to challenge you: How can you know if a student is proficient or they need additional practice in an area, if not for an exam? How can you compare students' performance for merit-based scholarships, if not for exams? How can you compare students from different classes, different schools, or different states in college applications if not for a standardized exam?
12
[Generic Fantasy] What makes iron so poisonous to Fae? I figure they're creatures of the "natural" world, and iron can be naturally found all over in ore veins and such.
19
Naturally occurring iron ores are generally bonded with other stuff in the form of magnetite, hematite, etc. This is different than refined irons and steels which are not naturally occurring and instead a product of civilization. So, the way I've generally understood it is it's only the processed/pure stuff which is harmful to them.
29
ELI5: Why is bread more nutritious than flour?
27
Really really simple explanation. The energy in bread and flour is contained in little batteries (sugar molecules). But, the batteries in flour have a coating over the plus and minus terminals that slows the electricity that can flow out of the battery. If you cook the flour (bread), the heat removes the coating on the terminals and the batteries in bread can deliver a lot more energy.
32
ELI5:When and how can you make a citizen's arrest?
38
In the US you can make a citizens arrest if someone has committed a crime in front of you, or you have reasonable suspicion that they've committed a felony. It's important to remember that this only extends to the point where you can hold onto the person but you must notify the police immediately, and you can't do any sort of investigative action. You are only serving as an anchor so the person can't get away until the police can take over the situation. You still hold liability though, so don't be too rough with them, and you better be able to back up your suspicion of why you believe they committed a crime.
34
ELI5: Why aren't Nagasaki and Hiroshima nuclear wastelands? Surely they would still be inhabitable due to the radiation?
67
Movies have lied to you about the effects and duration of radiation. Most of what movies show about how radiation works are distorted and exaggerated. This will also blow your mind: over 500 nuclear bombs have been set off in the US back when we still tested nuclear bombs, some as close as 65 miles away from las vegas or other cities.
76
[Marvel & DC] How strong is the Hulk compared to Superman?
18
The very strongest Hulk has ever been (World Breaker Hulk) is much much weaker than normal Superman. Superman is approximately 6.5x10^19 times stronger than base Hulk (Hulk is a 100 tonner while Supes benches the weight of the Earth).
21
ELI5: Capitalism vs. Communism during the Cold War, why does America care so much how other countries are run?
It's been a few years since high school. I understand the Cold War and Vietnam Conflict existed because of the spread of Communism, but I still don't understand why America was so threatened by a different ideological view.
89
It was less about ideology and more about rivalry. The US and the USSR were struggling for global dominance. Since communism and capitalism were largely incompatible, they were useful tools to force countries to pick one side or the other, and to stay on that side once it was picked. If instead of Russia, communism had taken hold in say, Greece or Argentina, the US probably wouldn't have cared nearly as much.
48
Why is teaching in academia looked at so badly?
I'm a PhD student hoping to graduate next Spring. I've got quite a bit of teaching experience over the course of PhD, and my goal after I graduate is to land a teaching-focused position at a university. I talked to my department chair today about becoming a lecturer in our department after I graduate next year (I will have to hang around this city for a year or two after I graduate due to some family things). He laughed and said "If that is what you want to pursue, then ..." and went on to talk about it. It was pretty obvious that his response was implying that me *wanting* a teaching position was a bit absurd. I have experienced similar scenarios over the course of PhD. Just recently, a professor in my lab asked if I was happy to be done with teaching now that the semester was over. I responded saying that it was nice to be able to get a lot of research done, but I enjoyed teaching so I wasn't really that happy. He laughed and said something like "Oh you like that? Well okay". My advisor routinely puts down my teaching ambitions with talks of why research is so important. I know this is nothing new, and everyone knows there is a stigma against teaching. But...is there anything I can do to be taken more seriously as someone that wants to have a teaching-focused career in academia? Or will I be laughed at for the next 30 years by research-oriented professors?
49
Academic snobbery and elitism. I've encountered a lot of PIs, usually the stodgy older ones, who look down on alternate career pathways, industry positions, pre-medical undergrads, etc. simply because they're not interested in an academic research career. I've known many people who have hidden their true career goals from their PIs and secretly sought out mentoring elsewhere in the department for biotech/industry related career trajectories for these reasons. I'd suggest not talking too much about it too much with those who clearly aren't interested in supporting your career goals, seeking out the best training resources available to you, and looking for mentors within teaching and faculty development programs who you can follow up with for support and input on your career trajectory.
72
[W40K] Why are ground troops still relevant?
Today, outside of territory occupation, most of the war is fought by drones, airplanes, etc; with ground forces being used only for small guerrilla style operations (special forces). Sure, a lot of troops are deployed to actually control land in hostile countries (eg occupation of Iraq by the US, or the current Centrafrican Republic deployment of the French). But where does it happen in W40K? If Chaos attack, wouldn't it be easier to bomb them from airplanes/spaceships than deploy thousands of guards and space marines? Same with Tyrranids, or Necrons, or pretty much everything else. If a large number of troops are deployed at any point, they would be bombed and destroyed easily. edit: I was not clear. I am not talking about specifically carpet bombings or exterminatus, but if say a bunch of Chaos space marines deploy in a given place, wouldn't it be easier to send W40K F16s to deal with them rather than a large number of guards?
52
Firstly these drones sound an awful lot like AI which is a big no no. Your enemies also have spaceships so you cant really just perch and fire unabated. You might not want to destroy everything in that area. Retrieving a relic or securing a position doesnt always necessitate orbital bombardment. Its also about resources. The Imperiums greatest resource is the sheer number of people they can throw at a problem. They also do use orbital bombardment and Exterminatus... frequently. Shockingly frequently. Its just we dont hear about the heroic battle of Feral World C3498-Alpha because a ship pulled into orbit evaluated the situation, dropped a bomb that destroyed all life and called for a new settlement to be sent because the last colony started growing dicks on their heads from worshiping chaos.
87
ELI5: Why do right wing Americans support Israel so much?
I tried searching with less that great results on ELI5. Basically, what is the cause of the right wing republicans in the US to have such a strong support for Israel; even expecting military action in some cases while being opposed to increased military presence in the american embassy in Afghanistan. I don't understand what is special about Israel. I could see if it has significance from a religious perspective but even then wouldn't an all powerful god be more than enough support? I feel like I'm missing something here.
27
It's not just right wingers. It's liberals as well. Republicans typically support because of the necessity for a strategic ally in the Middle East. Democrats typically support because the Jewish traditionally have a high voter turnout and not backing Israel will probably lose them enough votes and enough campaign contributions from wealthy and connected groups to lose an election.
30
ELI5: China vs Porcelain vs Ceramic vs Earthenware
Some of these may be overlapping categories but I have no idea.
84
All of these are examples of Ceramics, which covers the entire set of the other items you are asking about. Ceramics are typically any sort of hard shaped material formed at least partly out of Kaolinite Clay. The main differences between the types of ceramics are: * Earthenware, fired at lower temperatures than other types. It is not shiny, and is permeable to water. * Stoneware, shiny types of pottery like toilet bowls, not permeable to water. * Porcelain, which contains a high content of kaolinite. It's heated to the highest temperature resulting in a very hard shiny non-permeable surface. * China, which is a type of soft-paste porcelain that is composed of bone ash, feldspathic material, and kaolinite. These extra ingredients give it a high strength relative to other types of ceramics, allowing for thinner products (dishes etc...) Other than that it is prepared the same way as Porcelain, and in fact many items referred to as "China" are actually "Porcelain" instead.
39
CMV: All drugs should be legal
Yes, I mean crack and LSD etc. I wouldn't touch substances such as these for health reasons but I don't think I or anyone else has the right to forcibly prevent another adult from voluntarily using a substance. I think the effect this prohibition has on law enforcement is huge, meaning it puts a ton of cases on the department which takes away man power that could be used to lock up actual criminals (murderers, rapists, thieves, child molesters). As we've seen with the prohibition of alcohol, making substances illegal drives legitimate businesses out of the industry, i.e. only gangs, mafias and thugs will take part in the sale of such substances. This provides jobs to degenerates and gang members, and a source of revenue for organized crime. If all drugs were legal, Walmart and Amazon would put MS13 out of business.
23
Drug use have a lot of externalities that go beyond a single individual "voluntarily using a substance". Addiction is a chronic health problem that society pays for in many ways. They are less productive and often can't hold a job. They require a lot of public health services that society has to pay for. Addicts are more likely to harm themselves and others while under the influence. Finally, addicts will commit crimes to fund their habit if need be.
12
[Star Wars] Why can’t Jedi or Sith use the force to crash/crush enemy vehicles or starships during battles?
44
It takes practice and concentration. Something like a starship or large vehicle is usually beyond the capabilities of your average force users. In the middle of a battle there's too much going on to try and create a force crush unless you're a powerful force user and not busy trying to not get hit.
50
I believe that authoritarianism is preferable to democracy, CMV
There are a few key points that my opinion is based on: * I don't trust other people enough to vote for the future; as far as I'm concerned the vast majority are somewhat-educated Luddites who really don't care what happens as long as their head is on their neck and their pockets have some loose change (I know I'm the same). An authoritarian ruler is not concerned with such troubles, only in the running of their country/life's pleasures. * A King/Queen is far more efficient than voting once in a while. You don't need to wait four years to get another shitty party in power, but just hold a few demonstrations/public campaigns to raise awareness of issues for your monarch to act on as they see fit, at any time, from the next day to perhaps years later. * The illusion of actually having any power will be gone, for really, it *is* an illusion. Your government doesn't actually care about individuals, their opinions, or their troubles. All they care about is votes. Once they have them, they will do whatever they wish, namely, keeping themselves in power. If you have an authoritarian ruler who has no competition, the will seek only to improve their own legacy and country. I'm talking about a monarch here, not dictator; someone who has been raised by leaders, to lead. Edit: Sorry guys but I think that's it for the night. I've got tonnes to do and sleep to catch up on. I've dished the deltas and argued with the aggressors, and all in all it was a good first post to this sub, personally. Thank you for the time and effort.
27
All of your points work on the assumption that the leader of your country is going to be (for want of a better phrase) a 'good person' responsive to the views and interests of their citizens. Sometimes that'll be the case, sometimes it won't be; in an absolute monarchy, there's no guarantee that a good king will follow a good king. At least in a democracy, you're not stuck with some guy ineptly ruling over you for fifty years and no means to challenge his authority. Your points seem to touch on a deeper issue: that democracy is inherently flawed. In that sense you're probably correct but that means we have to work on improving democracy rather than switching to a system that completes removes the already fragile political agency of citizens. In this light, we can offer a non-authoritarian answer to each of your points. For point 1, we should make sure citizens are better educated about politics and government. For point 2, we should make sure our leaders are truly accountable to the general wishes of the people. For point 3, we should again make sure that governments do not possess absolute power in between elections.
41
[Giant monster films in general] Whenever a giant monster attacks a city, why do military pilots almost always fly right next to the monster?
Why would a military pilot fly right next to a giant monster destroying a city? For example in Pacific Rim, at the start of the movie, some F-22 Raptors flew so close to Trespasser that one of them literally flew under Trespasser’s armpit and got destroyed. Why would military pilots do such a thing when they can engage such a large target from hundreds of meters away? Edit: Or hell, in Godzilla: Planet of the Monsters, the human/alien alliance military were literally fighting Godzilla Filius with what I assume to be pretty advance fighter scooters/bikes. Why did *they* engage at such a close distance? Wouldn’t those bikes have missiles or something?
407
It's to keep down civilian casualties. If you manage to distract the monster by flying close to it (like that mosquito that annoyed you while you were trying to work), you give the civilians in the city time to evacuate. Of course you're taking a huge risk on your own life - but so do firemen when they go into burning buildings to save people trapped in them.
185
ELI5: Why does vibrato "sound good?"
40
Here are a few things i can think of - vibrato hides some pitch problems. With a straight pitch, intonation is more obvious - it gives the music more "texture", so theres more to listen for - vibrato is variable (in speed, pitch distance, etc), which allows more expression without changing the notes of a piece. - this is more theoretical, but i believe that music ultimately derives from the human voice/language, so adding vibrato may sound more natural/emotional than the "perfection" of straight tones. Source: about to graduate with a music degree.
58
[Star Trek] It's been said that Q aren't really "gods", just really advanced aliens who have technology that makes them damn near omnipotent/scient. The Borg stumble across a fatally injured and weakened Q and manage to assimilate it. Could they succeed at this? What would the Borg become?
18
Honestly, this feels like a scenario that could be best metaphoricalized by asking "A slightly brain-damaged pygmy lemur happens upon a smart-phone with no charger. How long until it becomes the CEO of Facebook?" Q and the Borg are so unutterably distant in terms of development that an assimilation attempt, even on a fantastically weak and injured Q, would seem a lot like a moth attempting to have sex with a blue whale.
27
[Avengers] Could Antman actually explode Thanos from the inside by crawling up his ventilation shaft?
I'm dead serious, would Antman even have the time to get to max size before being snapped away? Or would he even be able to get close? How would this all even play out?
26
Reality, power and space stone could easily deal with the issue - time stone could rewind on the off chance that Scott managed to get large enough to actually start doing damage. Of course that's not taking into account the fact that vanilla Thanos is so fucking durable that he can tank punches from Hulk - so no, regardless of the situation, best case scenario Thanos would use the gauntlet, worst case scenario Scott would be **crushed between those mighty purple buttocks**
50
ELI5: Why do US cities expand outward and not upward?
8,026
They expand upward when land is scarce or expensive, and they expand outward when the opposite is true. In most cases, it is the later. The US is _huge_ and available land is not a problem that we have to deal with. Most major cities have more than enough surrounding land to expand on to at a fraction of the cost of a skyscraper. There are a few exceptions, like New York where the value of being on Manhattan Island warrants the cost of upward expansion, but it just doesn't make financial sense for most cities.
8,971
How does MOND make dark matter unnecessary for explaining the movement of galaxies?
123
The idea behind MOND is that at very long ranges, the strength of gravity falls off at a lower rate than the one predicted by newtonian gravity (and general relativity). This would mean that the higher velocities of stars around the edges of galaxies could potentially be explained without the need for (a lot) of invisible mass, which is the first observation tl hint at dark matter. However, this is not the only reason we have for believing in the existence of dark matter, and MOND has a much harder time explaining the other ones; chiefly that dark matter seems to be necessary for the early clustering of mass we observe. Also, it's hard to introduce a new theory that does not mess with all the other predictions of general relativity.
100
I have read group theory is used to study a molecules symmetry but why would you want to know its symmetry in the first place?
25
The symmetries of a molecule affect its chemical and physical properties. For example water, H2O, is slightly asymmetric (looks like ^H O ^H ), which leads to it freezing in a crystal lattice instead of staying a fluid, and it happens in way higher temperatures than it otherwise would. Contrast CO2, which is symmetric (Looks like O C O ), leading to the fact that it's a gas in room temperature and is very hard to turn into a solid or liquid.
28
CMV If a business is failing, the taxpayer shouldn’t have to prop it up
So this is the article that got me thinking about this, for reference: https://www.google.co.uk/amp/s/www.bbc.com/news/amp/business-49598977 For anyone who isn’t going to read it, it basically says that a thinktank has come up with the idea of taxing supermarket alcohol higher than alcohol sold in pubs because more people buy their alcohol from supermarkets, which is hurting the business of pubs. They believe this will then help revitalise failing businesses. Now, I think this is an abhorrent idea for several reasons. If company A is failing because company B can offer the same product at a lower price, then company A deserves to fail. If somebody else has a better business model than you, and is able to take away your customer-base as a result then you are running a failing business. The answer they propose is for people to pay higher rates of tax when going to company B, to encourage people to visit company A instead. All this actually achieves is making the product more expensive for the customer. I think if people are able to buy alcohol cheaper and choose to do so instead of going to s pub, this just shows that the market is changing and pubs might not be an effective business anymore. Supermarkets have directly led to the death of independent butchers and greengrocers and while this is sad, I see no problem with it. The customer is the one benefitting from cheaper prices and if the market wants to buy all their items in one place, why is that a bad thing? Going back to my original point, the other side of the coin is that the government often provides loans or even grants to small businesses. I’ve got no problem with this for a new business starting out because someone might have an amazing idea, but not the capital to get it going. Sometimes that starting point is all a good business needs to succeed. But if the business is already running and not successful, I don’t see why the government (using taxpayer money) should then try and support that failing business. If it fails, it fails, it clearly wasn’t that good of a business to begin with. Essentially, once a business is up and running I don’t think the government should use public money to try and stop them from failing, or put an additional cost on the public if they choose not to support the failing business.
260
I would agree with this is a world where anti-trust laws were enforced. The problem with companies like Walmart or Amazon is that their size begets size. Walmart is so large, that if it chooses to it can put pretty much any style of local business out of business if they choose to. Even if the Walmart product is shittier, which is almost always is, they will still win because they can use the entire weight of their business to subsidize the products from the industry they are trying to stamp out. You see this with Amazon. Amazon is thought of an online retailer, but they are so much more. They're a software manufacturer, a phone and tablet producer, a cloud infrastructure company, etc. If they want to sell products cheaper than Walmart, all they need to do (and what they actually do) is subsidize their products from another part of their business. This can mean that a company like Walmart, if they choose to, can come into a town and drive out all local business because they are using the weight of all of their 7000 stores. This is what happens in a large portion of a small town in America. It's 100% bad for the consumer.
72
How do strawberries get infected with hep A?
Title. Is it something to do with the fertilizer like ecoli? Or is Hep A something that survives in the soil?
2,898
Hep A is transmitted through fecal particulates from an infected individual either directly or through contaminated sewage. You can contract Hep A by eating food that has been prepared by an individual with Hep A or had direct contact. Unfortunately studies have shown washing produce does not fully disinfect from Hep A contamination. The current strawberry outbreak was most likely due to direct contact from a positive individual and unfortunately many farm settings do not provide employees access to proper restrooms and hand washing stations.
2,482
eli5: How did philologists (people who study ancient languages) learn to decipher ancient texts, if there was no understandable translation available upon discovery?
To me it seems like this would be similar to trying to learn to read Chinese with absolutely no access to any educational materials/teachers.
790
Two ways: 1 finding cases where it's translated into another language, that's why the rosetta stone was such a big deal, it had several languages all saying the same thing on it, one of which was ancient greek, which we already knew so they could use that translation to work backwards. The other way, is what another commenter said, you look at where words pop up, if you keep seeing a word show up on things at greengrocers and farms, it's probably a plant of some kind. And once you know a few words it starts to become possible to work out the others through context.
856
[Marvel Cinematic Universe] When Cap's shield is thrown, why does its edge sometimes (elastically) bounce off things, while other times it (inelastically) gets lodged inside things? I've watched numerous movies carefully but I can't find any pattern or governing principle. Thanks!
158
Its all about edge alignment. If the edge is oriented such the it strikes on the surface of the shield's 'dome' then it bounces elastically. If it strikes on the edge in a scooping motion it cuts. Cap is just so proficient with it that he can control which alignment will strike the desired target.
142
ELI5: Why when I use a pen and it stops writing, I can go to another place on the paper and continue to write, but when I come back to the spot it stopped working at, it doesn't work?
103
Sometimes there's a tiny bit of grease on your paper, in an invisible layer. This grease (finger oil; french fry grease; maybe some dripped from a roller at the paper factory) stops your ball-point pen's ball from rolling, which stops the flow of ink.
60
ELI5:How do guitar pedals work?
I'm teaching myself how to play guitar on an acoustic, but I'm saving up for an electric. I want to know everything about pedals, and how they work with a guitar because I feel like it's necessary. If it helps narrowing it down I'm saving up for either a Fender Strat or Tele. Thank you!
38
An electric guitar, as you probably know, uses a magnetic pickup to transform the vibrations of the strings into an electrical signal. This signal is then carried to an amplifier and in turn a speaker (of course there can be PA systems and such but let's keep it simple.) An effects pedal will take this electric signal and manipulate it in some way. Exactly what the manipulation is will depend on the effect itself. So the pedal could modulate the signal, duplicate it, repeat it, alter the phase, distort it, boost it... basically whatever you want really.
15
[Star Wars] Would Luke had turned to the dark side if Han and Liea had died if they were killed instead of being captured twice at the battle of Endor?
32
At that point, yes. Absolutely. He was *inches* away from falling by the mere threat to Leia. If his friends die, there's no way he doesn't succumb. At that point, he wasn't even near to becoming the wise Grand Jedi Master he would be destined to become (talking Legends here, of course. In canon... well, you know). It's interesting to note that in the Legends continuity **[SPOILERS]**, he became so resilient that his wife was murdered by his nephew and he *still* didn't fall.
37
Why does an RH+ mother's cells not attack their RH- baby?
412
Hi, Rh positive mothers will not have antibodies to the RH protein. If they produced antibodies, they would attack their own cells. The issue with Rh occurs when Rh negative mothers produce antibodies against the Rh antigen in their baby’s blood. The Rh antigen in this case will be recognised as foreign by the Rh negative mother. Does that make sense?
394
Can executive functions be improved?
Hello. Apparently fluid intelligence can not be improved, yet. Can we do something about executive functions? Wikipedia article about executive functions says it can be improved at any age. I am 22. Perhaps, I can specifically do certain things since the prefrontal cortex gets myelinated between ages 20-30? Can adults above 30 do something to improve their executive function?
26
Studies show that meditation builds executive function. The most useful part of executive function is that it controls impulsivity, and that is something that meditation helps with. The less executive function you have, the more you are on autopilot when it comes to your emotional control and decision making. Meditation helps you recognize the physical signs of emotion, which allows you to head them off, or put a gap between feeling and action in order to make a conscious choice. "Thinking, Fast and Slow" by Kahneman covers a lot of this, definitely worth a read. Essentially, your brain is lazy and wants expediency and efficiency, so it tries to spend as much time on autopilot as possible. That time on autopilot does nothing to build executive function, so being conscious of, and questioning your automatic reactions to things and automatic thoughts and beliefs are also ways to build executive function (in addition to meditation). Gallant, S. N. (2016). Mindfulness meditation practice and executive functioning: Breaking down the benefit. Consciousness and cognition, 40, 116-130. Kahneman, D. (2011). Thinking, fast and slow. Macmillan. Luu, K., & Hall, P. A. (2017). Examining the acute effects of hatha yoga and mindfulness meditation on executive function and mood. Mindfulness, 8(4), 873-880. Short, M. M., Mazmanian, D., Ozen, L. J., & Bédard, M. (2015). Four days of mindfulness meditation training for graduate students: A pilot study examining effects on mindfulness, self-regulation, and executive function. The Journal of Contemplative Inquiry, 2(1). Tang, Y. Y., Yang, L., Leve, L. D., & Harold, G. T. (2012). Improving executive function and its neurobiological mechanisms through a mindfulness‐based intervention: Advances within the field of developmental neuroscience. Child development perspectives, 6(4), 361-366. Taren, A. A., Gianaros, P. J., Greco, C. M., Lindsay, E. K., Fairgrieve, A., Brown, K. W., ... & Creswell, J. D. (2017). Mindfulness meditation training and executive control network resting state functional connectivity: a randomized controlled trial. Psychosomatic medicine, 79(6), 674.
16
Are there any aspects of the mind/consciousness that have never been changed following brain damage?
Are there aspects of personality that remain constant no matter what?
63
It's been the model of structure creates function in brain medicine and neurosciences for a good long time. This was the "Astonishing Hypothesis" by Sir Francis Crick. There is not any function of neuronal brain without structure to create it.
15
[ the matrix] would the people in the program see neo as some kind of terrorist after he takes the red pill?
when i think about it, everyone sees morpheus as a god in the real world or a terrorist in the program. since all the stuff he's probably done to the agents. but when neo takes the red pill and he did all the stuff in the matrix and in the matrix 2. would there be news coverage of it? would the police investigate all his hacker friends and his family? he would be nowhere to be found until he pops back in again for probably only a few hours at a time. so like what does everyone in the program think of these leather clad group of domestic terrorists?
68
Firstly, in the real world Morpheus is seen as a bit of a crackpot, he just has a bit of a following. Yes, in the Matrix there are "news" reports that label them as terrorists. Sure the police might investigate stuff (we see them break in on Trinity) but once it's clear to the Agents that there's RedPills involved they take over, similar to how the FBI takes over.
58
What causes a burning sensation when you get salt in an open wound?
183
It is just basic electrophysiology. When you have an open wound, the solution around nerve fibers is directly accessible. Nerve fibers work via gradients of sodium and potassium inside vs outside the cell. If you really boost the sodium concentration outside the cell, it becomes hyperexcitable. Now, it is a wound, so C fibers (nociceptors) are going to be active anyway. The salt is going to act like an amplifier. It is different from the case of lemon juice, which alters the local pH. The C fibers are directly sensing the pH and sending a signal that your brain interprets as pain.
64
If a room was perfectly sealed from all external forces, would the air inside naturally settle with the heavier compounds to the bottom and the lighter to the top, or is air always continuously mixing?
20
Yes, mostly. Gas will naturally settle, like liquids, with the most dense at the bottom. Look up "gas stratification" to read details. This can be very dangerous in certain situations. For instance, a closed off industrial space such as a bridge compartment can have rusting metal. This uses up the oxygen. Or a closed off space that has bacteria at work using up the oxygen. The heavier air molecules left (other gases) such as carbon dioxide will fall to the lower portion of the room. This can asphyxiate someone who walks into that room. However, this does NOT mean that something like carbon dioxide (C02) will break up into carbon falling lower and oxygen settling higher. You have to take the density of the molecules into account, not the separate elements. Stratification can also happen with different temperatures. Look up thermal stratification.
14
Why does having diarrhea cause pain in the intestines?
I understand why constipation is painful, but why is diarrhea painful?
38
Diarrhea usually is caused by irritation to the intestinal lining. Your intestinal lining has pain receptors but your brain has difficulty localizing it specifically. The casing around the intestines (peritoneum) has pain receptors that your brain can localize. Irritation causes inflammation, which involves the release of chemical messengers that tend to have a spill-over effect. Inflammed intestines lead to irritated peritoneum. Intestinal lumen pain is a deep dull pain that is difficult to specifically point to as coming from "here." Instead, the answer will be more like "all up in this general area." Interesting corollary: Pain from appendicitis develops as the appendix becomes more and more inflammed. The appendix itself does not have awesome pain receptors, but its inflammation irritates the peritoneum. This causes a dull diffuse pain, mainly around the umbilicus. As the appendix gets worse, the pain will actually localize to a place called McBurney's point, the point where the appendix physically comes in contact with the peritoneum. This is usually in the right lower abdominal quadrant for most people, 1/3 of the distance from the anterior superior illiac spine to the navel.
27
CMV: Being uncomfortable with certain actions does not make you a bigot.
In a college class today I was labeled a bigot for saying that I am uncomfortable seeing two gay men making out. I even qualified it by saying that I am by no means saying it is wrong or that they shouldn't be allowed to do it, just that it makes me sort of cringe. I also said that I cringe seeing two straight people making out, mostly because super outrageous PDA is gross. Apparently, being uncomfortable with certain things is bigoted in the PC culture we all live in. I am uncomfortable when an 75 year old man marries a 20 year old. I am uncomfortable, as a tall male, dating any woman who is shorter than about 5 feet tall. I am uncomfortable around people who drink to much or smoke too much weed. The point of this CMV is to discuss the bigotry that is "inherent in your privilege of being a white cis-gender man" (real quote). I just don't think that being uncomfortable is equal to bigotry. Bigotry means intolerance, and I am in no way intolerant of gay people. Was I wrong? If I was, change my view. _____ > *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!*
24
In your defense, you said that its "outrageous PDA" that makes you uncomfortable, not the gay or straight angle. But your statement wasn't that public displays of affection makes you uncomfortable, it was that gay people engaging in such behavior do. Why did you specifically single out gay people in your statement, if it was irrelevant to your opinion? If you had said, "It makes me uncomfortable when mixed race couples make out". Or, "It makes me uncomfortable to see old people making out", can you see how people would interpret those statements. The implication of your statement is that it is something about the specific group that makes you more uncomfortable than usual.
21
ELI5: Why do cinder blocks have holes in them?
( http://www.dimensionsinfo.com/wp-content/uploads/2010/02/Hollow-Block.jpg ) Someone told me it's because it dries faster when being made as opposed to making one whole block. What I want to know though, is the effect (if any) it has on infrastructure. Would using whole cinder blocks with no holes be any different than using the ones with holes? Wow! That was fast, thank you all for your responses!
644
Cost. Making them solid doesn't make them very much stronger but adds significant cost. Also n some construction, rebar is embedded into concrete poured into the stacked blocks to add strength, which would not be possible if they were solid. Being able to add strength only where necessary minimizes cost.
582
Why are there no Chihuahua or Great Dane sized cats?
Why is there less variability in cat breeds as compared to dog breeds? If there is selective pressure in a village or area to have a huge or tiny dog, why wouldn't the same pressure apply to cats?
84
Because nobody's tried to breed them for that. Dogs were purpose-bred for specific tasks. None of them were specifically bred to be large or small, it's just that the slightly larger or smaller ones were better at some job, so those were the ones that were used for breeding. Repeat for a couple dozen generations, and you've got a larger or smaller dog. Cats were not bred for a job. They were already doing the job (catching pests in barns and granaries) pretty well. Early farmers noticed this and let them stay. The only selection going on was for cats that were not afraid of people.
47
CMV: Candidates should be able to bring notes, tablets, phones, ect. to political debate stages. Debates should also not be shown live, but delayed and showed with fact checking done my multiple organizations.
For some reason, it has always been a rule that candidates are not allowed to bring outside help to debates. The Democratic debates tonight will follow this rule, as well as the Republican debates that already took place. If candidates were allowed to bring sources, facts, tablets with internet access, ect it would be far easier for politicians to be called out on thier BS *during* the debate. To roughly paraphrase George Bush senior, "If i tell a lie on stage, 10 million people will hear it. When it is corrected the next day on the news, 10 thousand will hear it." We desperately need debates where candidates can be called out *on stage* for telling lies. Carly Fiorina was on the debate stage telling lies about the planned parenthood video. This was certainly called out on the news afterward, but not many people have seen the rebuttals. Lies can easily be put out there with no way to effectively counter. They also gain instant legitimacy because they have been said in a presidential debate. Debates should also either not be shown live, or have people on the scene whose sole job is to read facts about what candidates are saying. Too often candidates are allowed to stretch, bend and outright proclaim falsehoods because no one is able to counter them with hard evidence. (either independent fact checkers can be chosen, or both sides are allowed to choose their own fact checkers) The way we do debates is antiquated and needs to change. CMV _____ > *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!*
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I think debates, for most viewers, are less about policy and more about how candidates present that policy, along with themselves. Many voters who have a specific issue that they really care about will just look up information on different candidate's ideas, but the debates serve a different purpose. A future president needs to be able to think on their feet, take questions under pressure, and come out sounding like they know what they're talking about in a crunch. If the future president is negotiating a deal with Putin, President X will have done preparation before hand, but they won't be sitting in the conference googling the validity of everything Putin says. A debate is the same format: the candidates rigorously prepare beforehand, but the goal is to make them apply that knowledge on the run.
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[MCU]: Aside from intentionally being stripped of its power, are the effects of the heart-shaped herb permanent?
Does T'Challa have to worry about eventually losing his powers if Erik really did destroy *all* of the herb, and was T'Chaka still more powerful than a normal human when he died?
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Probably. [Black Panther film spoilers](#s "The gardener told Erik Stevens that the herb was needed for the *next* Panther, and clearly didn't want to burn it. Telling him that he'd need it himself in a few years would have been a good way to save the crop, but she didn't try that.")
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ELI5: Why is saltwater marine life usually so much more colorful and vibrant?
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If you’re talking about aquarium fish, it isn’t because they’re saltwater. Plenty of saltwater fish are boring. It’s because they’re tropical. Animals throughout the tropics are more colorful and if you were going through the trouble of having a saltwater tank (which is very difficult to take care of), then you might as well select the most colorful and interesting looking ones. And in the ocean, there are way more to choose from. People think the reason tropical animals are more colorful is that given the biodiversity and density it’s more important for species to find each other for mating than to avoid predators.
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Why is it that we as humans generally dont eat carnivorous animals
Apart from a few cases we tend to eat vegetarians and as far as I know carnivores don't tend to eat other carnivores. Why is this?
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It's easier and cheaper to domesticate and farm herbivores. The higher you move up the food chain, the more energy you need to sustain life because of the energy loss between levels. In order to feed a pack of wolves, you have to first raise some sort of food source for wolves. You also don't have to worry about cows eating farmers.
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ELI5:How are the courts able to try a minor as an adult?
I always thought law was pretty rigid, so if someone is a minor and they're being charged with a crime, they would be tried as a minor. However, there are many cases where a minor gets tried as an adult. How do they do this? What's the law that allows them to do it, and is it only with specific crimes?
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IANAL so pinches of salt. It's basically a matter of severity, intent, and the individual circumstances. Consider 2 hypothetical incidents involving a minor (Lets say about 7-9 years old). In the first, a kid somehow gets hold of a gun, and shoots someone they don't like - killing them in the process, but makes no effort to hide or destroy any evidence. When interviewed and asked why they did it, they either don't really know why they did it or didn't think it'd kill them (they'd go to hospital and get better). In the second, the kid keeps a diary where they detail and plan killing someone they don't like. How to get the weapon, where the target goes, how to cover up their tracks - the entire thing is pre-meditated and planned to deliver the result. They know they're doing something wrong and plan to evade getting in trouble for it. The reason we separate trials for minors and trials for adults is because it's generally accepted that children have less understanding of the consequences and severity of their actions, and as such need to be handled differently. In the second example, they've demonstrated through their actions that they understood the consequences of their actions - and as such it may no longer be appropriate to try them as if they didn't. There are also a few caveats that would apply more to children. If in the second example the person killed was an abusive family member, then despite the pre-meditation and understanding of consequences they'd be more likely not to be tried as an adult since it's difficult for a child to escape abuse from a family member. However an adult doing the same may be more likely to charged with manslaughter rather than self-defense (assuming they were not in immediate danger, and were reacting to a history of abuse by someone) as they are assumed to be better equipped to deal with the problem through legal means. So that's for the why. The 'how' is basically a case of 'if it's necessary, then do so' - but a judge can't just turn around and decide to try a minor as an adult. There are a lot of checks in place that have to be satisfied before it can happen.
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ELI5: Why do old jazz recordings sound better than other records that have been released later on?
It seems to me as if most jazz records of the 50's and 60's sound way better in recording quality than most of the other music at that time (e.g. blues, country, rock, etc.) or even later on. Why is that?
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**Why do they sound better than most of the other music at that time?** Jazz music, including its crooner singers and big bands, was some of the most popular mainstream music at the time. As a result, they had more budget and resources for good recordings. **Why do old jazz recordings still sound better than newer music?** From a music perspective, many of the musicians who were playing on the jazz records of the 50s and 60s were seasoned live performers and session musicians. The way records were recorded back then involved the whole band to be in the same space performing the music. As a result, a lot of these musicians had lots of experience and good chemistry with each other, which meant they could groove better and bounce off each other musically. In later times, as studio technology evolved there was less of an emphasis of capturing the perfect recording of the performance in the room, as session musicians could be swapped in and out and record on completely different days, multiple performances could be cut together and edited to fix mistakes, etc. Some people would regard say that as a result, some of the soul and imperfection was removed in favour of higher fidelity and perfect performances. Speaking of music technology, the actual equipment was very different in the 50s and 60s. Because they couldn't record lots of microphones at once, often bands would have to perform around one or two microphones and members would have to physically move back and forth in the room to adjust their volume. This made the sound of the room a very important basis of the sound. Modern recording methods favour multiple microphones allowing for the complete isolation of each member of the band, meaning that only the pure instrument is captured, allowing for greater fidelity, but without the character of the shared sonic space being in the record.
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ELI5: During conception, are there hundreds of thousands of different, unique potential people who don't get the chance to be born?
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Here's the thing that gets me: it's not even enough to have a particular sperm and egg combination to determine a self. Identical twins come from the exact same sperm and egg, but are different selves. Even after the enormous improbability of your particular sperm and egg meeting up, your parents could still have ended up with someone who wasn't you. We really don't understand what makes a self.
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[Animal Crossing] How do you end up in a world of anthropomorphic animals?
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If you're asking how the player character got there, in their world anthropomorphic animals are simply normal. It's pretty consistently implied that they moved there. If you're asking how to get into such a world, you need some kind of interdimensional portal or something.
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CMV: I'm a woman but don't think women have structural barriers to success.
First of all, I realize this is not *that* unpopular of an opinion, except that I'm a 1) college student in a very liberal area and 2) a Democrat and have been for life, so this view doesn't align with many of my peers. I also want to note that I have been privileged enough to grow up fairly well-off (upper middle class) and am aware that I do not see many of the structural or societal barriers that may exist for people without my same privileges. But I took one of those political typology tests today with a friend of mine - the one from [Pew Research Center](https://www.people-press.org/quiz/political-typology/) - and got what's called an "Opportunity Democrat." The description is as follows: >Democratic-leaning and financially comfortable, Opportunity Democrats have liberal attitudes on most issues including the environment, immigration and homosexuality. They stand out from other Democratic groups in their strong belief that hard work is enough for most people to get ahead and for being somewhat less likely to see structural barriers facing blacks and women. They are supportive of U.S. engagement abroad and involvement in global markets. I want to say here that I do not believe that of racial minorities, e.g. I believe there are absolutely structural barriers to success, especially for African-Americans, but also Latinos and Native Americans. I am of color, although I'm mixed-race and also an overrepresented minority (Asian, but probably not the kind you're thinking). All that said, I don't believe that women have structural barriers to success. I think that I have worked hard, and have worked for every academic success I've had (bolstered by privilege, but also reliant to an extent on my own work), and I do not feel like I have had to work harder than my male peers. I have frequently outperformed them, even in subjects often considered "men's subjects" (science and math). I am a STEM major. Yes, some boys have been sexist, but apart from that I do not feel like I have been dissuaded by anyone. I have faith in my own capabilities and have been lucky enough to achieve good things so far. I just do not feel like my gender has been a barrier to my success. Admittedly, I am in college, and this may change in the workforce. But in the places I have worked (like for summer internships), I have not noticed much institutional sexism, either. There are definitely less women at high levels, but I feel like that can be chalked up to women being unfortunately biologically predisposed to needing to take time off to have children. My mother is also a great example of a very high powered woman who had children and went back to work and is very high ranking still. I know I live a very specific life, but I'm struggling to see what structural barriers exist that make it harder for women than men. I think with racial minorities, I can easily point to things - e.g. redlining creating poorer school districts so that even today majority-minority schools are underfunded - that are structural and make it much harder to get ahead, but I cannot with women. Especially in the West, I just don't see what I'm missing. Please CMV. I've been yelled at all day about this.
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I think you're not seeing the gender barrier because you're focused on the class barrier, that is much more apparent from your vantage point. Once you have a certain status or class, all barriers are weaker compared to those experienced by those in lower classes.
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[Star Wars] How many separatists were there? If you would take away the droids, how many actual people were opposing the republic?
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The Separatist Movement was thousands of worlds which aligned with Dooku, but the majority of the "senate" were leaders of guilds and corporations, not government. And their main motivation was money - the Banking Clan loaned to both sides of the conflict, and the Trade Federation sold droids to their side. But there were standing armies that weren't droid based, and these were the most difficult battles for the Republic to fight (Geonosis, Umbara). And there were independant groups who were allied with the Separatists, most notably the terrorist group Deathwatch from Mandalore.
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[star trek]suppose I replicate some ...fish and ships. If I looked at the fish meat under a microscope would I find actual codfish DNA, or is there no need to make the recreation that elaborate?
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It wouldn't be that accurate. The replicator is a combination of a bunch of technologies. One of those is the protein synthesizers that used to be the only option in the past. In short it doesn't just blindly reproduce a single pattern like a transporter, going full matter replication is the last resort. There's no need to capture DNA.
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ELI5: how the heck can a ladybug (or other bug) hang onto the outside of a car window at highway speeds like it’s nothing?
Glass is slippery! Wind blows hard! It’s a bunch of bologna
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The friction of the glass means there is a tiny layer of air that is almost stationary called the boundary layer. The insect is small enough to be within that layer. Imagine a three lane road where you have loads of cars using the road sensibly and pulling into the slow lane when there's no other traffic. Now imagine there's a series of slow moving trucks in the slow lane. These are what cause the friction. Other cars in the slow lane get slowed down to the speed of the trucks until they can get room to overtake. Now imagine the insect is a learner driver who is scared to go in the fast lane, so they sit behind a big truck and go at the same speed as them, without fear of the fast cars.
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CMV - I believe that Biking will never be a viable, large scale mode of transport in the United State's and investing in infrastructure for bikes is a waste of resources that could be better spent on other things.
CMV - Biking sound's good at first glance, but when all of the factors are considered, it has some serious flaws when used as a large scale transportation system. The biggest flaws that I can think of are listed as follows. 1. A large segment of the population are not physically able enough to ride bicycle for long periods of time because of legitimate reasons other than being "Fat Americans" such as being disabled or being a member of our increasing elderly population. 2. Winter weather make's biking almost impossible in the northern parts of the country that are also some of the most densely populated regions that would otherwise be the most viable places for biking. 3. The distances that many people need to travel are just too long for people that don't live in the most urban city's. 4. People that have kids would have it very hard using a bike as transport in a safe and practical way. Also transporting the food for a family on a bike is not very practical. 5. Most of the target poor people that are supposed to benefit from this infrastructure are already excluded for reasons posted above. Making the biking infrastructure largely a playground for young white "Yuppie Types" that are using it for fun, not as transportation. 8. One of the biggest reasons not to invest in bicycle infrastructure is that it is inevitable that the majority of passenger vehicles will be Electric powered in the near future, with City's having fleets of self driving Electric buses.
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What biking infrastructure? Bike lanes? It's just some extra paint and a law not to drive in it. Raised bike paths? Can be walked too. Any biking path can be walked except the painted ones on the road. Bike racks? Every single one I've ever seen got a lot of use out of it.
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ELI5: The reason why a Television show has an opening on every single episode after the first initial episode of a new season... when it could be replaced with a short title introduction.
I've always wondered this since I was a kid, sorry if this has been asked before.
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A lot of people are not progressing through the season, like on Netflix, but are glancing it during programmed television. It's important to brand identity and recognition by outsiders of glance-watchers. Quick, attach a category filter, before mod-bot arrives!
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[Marvel] Could healing mutants like Wolverine provide an endless supply of donated organs and blood?
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No. Your immune system will reject organs it doesn't recognize. Healing factor includes a hyperactive immune system, so Wolverine's blood will fail to recognize you and fight you off. His blood is poisonous. Wade Wilson was given his healing factor, but that was a much more complex process than a blood transfusion.
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