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Is a 'randomly' generated real number practically guaranteed to be transcendental? | I learnt in class a while back that if one were to generate a number by picking each digit of its decimal expansion randomly then there is effectively a 0% chance of that number being rational. So my question is 'will that number be transcendental or a serd?' | When we talk about probability distributions on the real numbers, we are really ultimately talking about a *measure*. A measure is a rather technical way of assigning a length to an interval or a volume to a region. We can actually define many measures on the real numbers, but we typically stick to so-called *Lebesgue measure*. This is a measure that allows us to assign "lengths" to subsets of real numbers in such a way so that the length of the interval [a, b] is just what you expect: *b*-*a*.
We can forget about most of the technicalities. What's important for your question is that Lebesgue measure assigns measure 0 to single points. That should make sense: the length of a single point is 0, right? It's also important that any measure satisfy certain properties. One property that makes a lot of sense is that if *A* and *B* are two *disjoint* subsets (that means they don't overlap), then the length of their union is just the sum of their lengths. For example, the measure of [1, 3] together with [5, 6] should be 2+1 = 3, and it is. What's interesting about measures is that we extend this rule of *finite* additivity to *countable* additivity. So if we have *countably* many disjoint sets (and there could be infinitely many of them), then the measure of the union is the sum of the measures.
So what happens when we combine those rules to a countable set of points? For instance, what is the Lebesgue measure of the set N = {0, 1, 2, 3, 4, ....}? Well, each number in the set is a single point and has Lebesgue measure 0. There are countably many numbers in N, so the Lebesgue measure of N is just 0+0+0+... = 0. This applies to *any* countable set. All countable sets of real numbers have Lebesgue measure 0. That should also make sense. Remember that the real numbers are uncountable. So a countable set, even though it may be infinite, is very small when compared to the uncountable set. Our sense of that smallness is reflected in how we construct Lebesgue measure.
Okay, so what does this have to do with transcendental numbers? Consider the set S of algebraic numbers, that is, all real numbers that are a root of some polynomial with rational coefficients. It turns out that S is countable! How can that be? (We need to use the fact that the rational numbers are countable.) We can actually just make a list of them. Forget about degree-0 polynomials since those are constants. What about degree-1 polynomials? Each degree-1 polynomial is determined by 1 rational number (we can always assume the leading coefficient of the polynomial is unity). There are countably many such polynomials, each of which has at most 1 real solution. So we get S*_1_* = set of real solutions to degree-1 polynomials with rational coefficients, and that is a countable set. Then we move on to degree-2 polynomials, and there are countably many of those since they are determined by 2 rational numbers. Each of those degree-2 polynomials has at most 2 solutions, so there are countably many solutions. (Two solutions times countably many polynomials = countably many solutions.) So S*_2_* = set of real solutions to degree-2 polynomials with rational coefficients, and that is a countable set.
We can generalize clearly. Let S*_n_* = set of real solutions to degree-n polynomials. That set is countable, being at most the size of finitely many countable sets. Finally, we see that S (the set of algebraic numbers) is the union of S*_1_*, S*_2_*, ..., S*_n_*,... . Here we have to use the fact that the union of countably many countably sets is itself countable. The proof is not that difficult. If you have a list of the members of each set, you can form a list of the union by listing them like this:
> S*_1_*(1)
> S*_1_*(2)
> S*_2_*(1)
> S*_1_*(3)
> S*_2_*(2)
> S*_3_*(1)
> ...
The pattern is rather simple. List one element from the first set. Then the next unlisted elements from the first two sets. Then the next unlisted elements from the first three sets. Then the next unlisted elements from the first four sets, and so on. Eventually, every single element in the union will appear on the list.
So now once we know that the algebraic numbers are countable, we know that their Lebesgue measure is 0. We say that *almost all* real numbers are transcendental. So, for instance, if you consider the uniform probability distribution on the interval [0,1], there is probability 1 that a randomly selected number is transcendental. | 195 | 444 |
ELI5: Why aren't electrical prongs hot when they're removed from an outlet? | If high amounts of energy are being conducted through these prongs, shouldn't prongs be glowing hot when they're removed? | Heating occurs when there's a significant amount of resistance.
Significant resistance can occur if the material you're using is a poor conductor, or if you're using a conductor that's physically too small.
In the case of the prongs of a plug, they're both made of metal (good conductor) and fairly large in size. Therefore, there's no major resistance, and they don't heat up noticably. | 224 | 147 |
Considering leaving academia so I can spend more time on research... | Recently I have been feeling that the biggest obstacle between me and the research I want to do is the university and academic system that is supposed to facilitate it.
I work on theoretical projects in physics requiring no significant resources other than time and mental effort. Teaching, grant applications, performance reviews, meetings and other requirements are a constant drain on my time and energy.
Looking ahead, it seems that career progression within academia will only lead me deeper into this administrative swamp and further from the research I actually want to do. When I look at the day to day lives of top professors in my field, I realise this is not a life I want. I don't want to teach, manage, or do any paperwork whatsoever. I just want to work on my research. It seems crazy to follow a career path (a very demanding and competitive one at that) where the end goal is a life I don't actually want.
I still want to do my research though, and all I need to do so is money. So I have been thinking more and more seriously about quitting academia and looking for part time work that pays well enough for me to spend half my time focused solely on the research I love. I have good relationships with people in my field and I doubt doing so would harm any of my collaborations.
Is this a crazy idea? Has anyone else followed this path? I would love to hear about your experiences if so. | If you treat the non-research part of your current position as this hypothetical 'part time work' - do you think it currently takes up a greater percentage of your day-to-day than an entirely separate, independent job at some company would?
A part-time job also often comes with lots of additional overhead: scheduling, training, performance reviews, travelling, queries on work-phone, mental distraction by doing work totally unrelated to your research, and so on. For example on that last point, the admin of writing grant applications can certainly be beneficial time spent viewing and planning your research at a higher level.
Maybe you will find you've even less time to allocate to research? | 76 | 49 |
CMV: Hard word limits in essays reduce the quality of work | The premise is simple. Having a hard word limit (e.g. 10000 words), with penalties for being over that count (whether mark reduction, ignoring the last x words or just discounting the entire thing) reduces the overall quality of work.
I am all for soft limits, e.g. aim for 10000 words, since for most essays that will be the 'best' amount.
There are a few reasons behind this:
1 - the 'goal'. If you set a limit of 10000 words, people will aim to hit that, even if there is no need to. I've just finished my dissertation, and a lot of people I've spoken to 'finished' theres at around 7000 words, but felt they had to bump the word count up to 10k. Aside from just being wasted energy for both the person writing it and the person reading it, the overall quality of the work is often reduced because it means adding worthless or low value information.
2 - word reduction. There are plenty of cases where someone will write over the word limit, and have to cut down on the words. I'm one of these people, and there are always 2 steps to word reduction. What information doesnt add anything? And where can I swap words to cut down the number? Removing useless information seems perfectly reasonable to me, but that could be achieved through soft word limits. The issues is picking through the exact words used to reduce the number. Typically it makes the sentences flow worse than they used to, and makes it a less pleasant reading experience overall.
3 - imposed limitations. There is a place for limitations, and for the most part they dont egregiously affect the project. There are however a subsection of people who simply do stellar work. Putting a word limit on can be a limit to the actual substance of the project. There is only so much you can reduce the information you've written, and if someone wants to go outside of the norm, they shouldn't be prevented from doing so.
Now there are 2 answers I'm anticipating. The first is the time taken to mark essays goes up if the average length goes up. It's not wrong, but I feel this is a problem that ought to be met at a staffing level. If it takes 10 percent longer to mark each essay, get 10 percent more staff marking it. I know this isnt necessarily practical, however this is mostly aimed at university level work where (to my understanding) there is actually the money to throw around a little more freely.
The second is that it means people feel they are expected to go beyond. I dont disagree with this entirely, but people already feel they have to go beyond what's expected a lot of the time. Giving the freedom to do so more easily seems beneficial to my understanding.
Edit: looks like my phone is playing up and replies arent going where I mean them to. Trying to sort it | Setting a hard word cap is essentially an exercise in word economy, which is an extremely useful skill to have
And if a future boss asks for a one-page brief, you better fit that sucker on one page. Don't give them 3 and say "but it's stellar and flows better this way." | 84 | 48 |
eli5: At sundown, why does the sky have a gradient of several colors? Is it 2 colors blending and naturally creating the other ones as a result from mixing? | There is a different amount of atmosphere that the light travels through. When the sun is above you, that is the shortest amount of atmosphere that light passes through to get to you, at sunset and sunrise the light is passing through a lot more atmosphere, gradually changing it's appearance | 24 | 33 |
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Is there a consensus among economists on supply-side economics? | Supply is one part of the equation. Demand is another. Their relative elasticities tell you which will respond more strongly to a given exogenous shock, but to ignore either is to be missing a major part of the picture.
So... yes? And also no?
Edit: the honest answer is that used in the way you’re probably using it, it’s a political term pretending to be an economic one and it’s so trivial and poorly theorized that it falls in the not even economics” realm and is therefore not even a question that enjoys the consideration required for a consensus. The “tax cuts pay for themselves always” argument comes from the Laffer curve, which is simply a visualization of a trivial insight (that revenue at 0% and 100% is $0, therefore there is a revenue maximizing point somewhere in between), but definitively determining the shape of that curve and the location of that revenue maximizing point is impossible, at least with modern computing technology. Therefore to make any sweeping claim about the effect of, say, progressive taxes writ large with regard to revenue or even economic growth is inherently useless. | 23 | 15 |
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ELI5: How can we measure the velocities of the redshift of stars? | Are they measured assuming the earth itself isn't moving or is this somehow taken into account?
| You are basing this on a false assumption, movement requires two things, an object and a point of reference, however the most important part is that **these are interchangeable**. It is not a matter of "is the star moving or is Earth moving," because according to physics, both principles are exactly the same. | 17 | 73 |
ELI5: If influenza is always mutating, why does getting a flu shot help? Doesn't the shot only prevent attacks from a certain strain? | Every year the world health organization researches which variation of the flu is going to be most common. After they come to a decision, the flu shot is made specifically for that virus. The flu shot contains a dead part of the virus that your body can identify and recognize when you actually come in contact with the virus later on. | 111 | 137 |
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[SPIDERMAN] what is Green goblin goals and motivations? | I'll admit I don't really read much comics, 90% of what I know of Spiderman are from cartoons I watched as a kid and the movies, but in all of those I don't really remember GG having any goals apart from being a dick to Spiderman just because, and maybe "getting rid" of Nosborn problems by violence, but apart from that why does he do what he do? | Varies depending on the medium. Most of the cartoons and movies center around Norman’s mental instability and desire for power going over the edge when exposed to the Goblin formula, turning him into a supervillain to achieve those goals. And when Spider-Man starts stopping him, Green Goblin grows to hate the wallcrawler and want to crush him under his heel.
In the comics…honestly, he kinda just outgrew that phase by now. Norman flat out admitted to Peter that their conflict was the only thing that ever really made him feel *alive*. Not being a father or husband, not a successful businessman and scientist, not having the respect of everyone, or even being a supervillain ready to take control of the criminal underworld, but having a genuine opponent who hated him as he hated them, but neither could fully defeat or break the other into gaining victory.
Even in Dark Reign, when Osborn objectively won against the superhero community, what’s at the end of his wish list and the only thing he truly has passion for throughout the time? Killing Spider-Man. What does Norman do when he loses all that? Shrug and go back to fucking with Peter. The man doesn’t care about power or anything outside of how it can be put to utterly crushing Spidey into the dust.
TL;DR: Green Goblin’s character development is becoming Spider-Man’s Black Manta. | 35 | 26 |
CMV: Using the words "right" and "left" to lump radical and moderate political groups together is unhelpful | I see little benefit in lumping all left-wing or right-wing groups together and describing them with one term. It leads to people discussing groups such as Antifa or Neo-Nazis using the general terms of "left" or "right" instead of their specific names. This leads to needless division and hostility as moderate groups are called out for the actions of radicals. I don't see why people can't just call them "leftist extremists" or "right-wing radicals" instead of using a term that can describe half the country.
**NOTE** I am not saying that partisan political groups can't be left or right wing. I am saying that blaming their actions on the "left" or the "right" instead of placing the blame on those specific groups is unhelpful.
"Unhelpful" in this CMV is referring to political dialogue and discussion.
CMV.
> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[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)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | It depends on your goal. If your goal is to *create* division--which is definitely the case for certain politicians, activists, academics, and media entities--then lumping together moderates and extremists is very useful. | 104 | 962 |
Why is iron-oxide considered a ceramic and not a metal? | Is it because of its mechanical/physical properties?
Or is there something else that "makes" it a ceramic?
Thanks in advance!
| Metal atoms are connected via metallic bonding
Ceramic atoms are connected via a mix of covalent and ion bondings (usually)
The change in mechanical properties result from this difference making ceramic extremely hard, heat resistant etc. but also very brittle and sensitive to shocks. | 89 | 243 |
How do Palaeontologists build image of an organism from fossils? How accurate is their method? | I was recently saw a rabbit skeleton and could only imagine a monstrous creature but not a cute bunny. It got me thinking if dinosaurs were actually that intimidating. | Not a paleontologist but Comparative anatomy gives a lot of insight into fossils - e.g. Proportionally long legs (specifically lower legs) correspond to animals adapted for speed or sprinting. Robust bones are indicative of heavy set animals with lots of muscle of fat. Unusually dense bones can be indicative of aquatic animals.
The texture of the bones themselves can reveal even more information - deeper scarring on muscle attachment sites means beefier muscles in that area; rugosities and landmarks on the bones can reveal places where keratin sheathes would anchor to or where blood vessels flow. Quill knobs are seen where feathers anchor on some dinosaurs.
Some fossils are preserved well enough to preserve scales, skin and feathers. A handful of fossils even preserve melanosomes which determines colour. Evolution also leaves lots of remnants of a species' ancestry behind - for example: pliosaur, crocodile and spinosaur teeth are extremely similar but theropod (the group of Dinosaurs spinosaurus belongs to) teeth are flat with serrated edges, so even though spinosaurus teeth are evolved convergently to other fish-eating animals, they have subtle remnants of traits only seen on theropod teeth, in this case being slightly less circular and having faint ridges where the serrated edge used to be. Teeth themselves are hugely informative of diet and environment too to the point that microscopic wear marks can tell you how a herbivore moves its mouth! In mammals, the patterns in teeth is even more unique (compare the pattern on an elephant molar to a cow to a human).
All these things offer different pieces of the puzzle. Phylogenetic bracketing takes all these clues, adaptions and identifying features and models the most likely relationships, this can then reveal where along the chain certain traits pop up (for example, feather-like filaments have been found across a range of distantly related dinosaur and even pterosaurs, indicating that all dinosaurs probably evolved from an animal with some level of proto-feathers). All of this can also be compared with chemical isotope analyses of fossils and the formations they are found in, to build up an even better picture. | 96 | 321 |
ELI5: Why are signatures still relevant, if they can easily be forged? | Even in movies, you often see the bad guys trying to get a real signature from the good guys. Why cant they just be forged? | The strength of most signatures is the act of signing with a witness. The scribbles on the paper are just a physical way to note the act.
For example, signing the pad at the store for credit card purchase. The strength of the signature lies in the security camera footage of your face doing the signing.
In many legal documents where the strength needs to be increased, a third party notary is used where another neutralr person attests to your identity (by you providing gov ID card of some sort) and the signature act. | 75 | 49 |
What are some fun real world programming challenges to solve? | I wanna do some programming challenges to improve my programming skills and speed. I don't really like doing coding challenges like code golf etc that much even though I've done some. What are some fun challenges that i can solve that would teach me different kind of real world problem solving?
My interests are web application development and I like devops type stuff (I know its a buzz word).
What are some cool problems I can try solve.
Some stuff I've thought of:
1. Web scraper that indexes to solr or Elasticsearch.
2. Do something with AMPQ. I struggle to understand what this protocol is supposed to really be used for.
3. Do something cool with DNS to enrich data
Any other cool ideas? | Try building a website with microservices backend, sounds like just what you need.
You'll use a Message Broker (AMQP implementation) to wire microservices together, then try deploying it with kubernetes afterwards (and there's your devops).
Granted it's a complex enough setup for a solo project, so keep it small and stupid :).
If you really want to, you could shoehorn elastic somewhere in it. Otherwise I'd keep it simple with a SQL DB. | 15 | 49 |
If dark matter is found and proven, how much would that change physics and math? | I don't have a math background so the in depth answers will be above me, but I just wonder if a discovery like proving dark matter will have a fundamental shift in math and physics theories?
| Most people already work under the assumption that dark matter exists. All of cosmology just assumes it is there. The real question comes down to what is it made of, what sort of things make up dark matter. We believe it is there but currently only have guesses as to what it might be, what other properties it has and therefor how to even begin looking for it.
So the better question would be how would our understanding change if we discovered it and learned what sort of properties it has, but we jsut don't know enouhg to answer that question yet. Until we can learn more about what dark matter is, we just don't know what consequences it could have on our understanding. Maybe it turns out to be something we have already guessed, in which case maybe not much changes. Maybe it will turn out to be something completely different than anyone ever guessed which could change our understanding quite a bit.
Sorry if it isn't a great answer, but we sadly just don't know much about dark matter yet, and thats why people are trying to find it. | 1,837 | 3,072 |
[IT chapters 1 & 2] The first film makes it seem like only children can see this clown, chapter 2, it’s apparent that adults can indeed see pennywise. But then there’s parts where other adults don’t notice him. Why are the losers seemingly the grown ups who can see the clown? | And why does pennywise *only* target the kids? | Generally It arranges things so that adults don't notice (or actively ignore) It's activities. This means It's targets are more isolated and easy to nab. The Losers can still perceive It because they've all been marked by It's activities personally; even then, they have difficulty remembering anything about the encounter, so their perceptions are still disrupted.
Pennywise targets kids because it's easier to manifest a kid's fears. Adult fears are usually lame stuff like mortgage payments, not so much with the rending claws and gnashing teeth. | 62 | 60 |
If temperature is the cumulative speed of molecules in a material, what exactly produces the infra-red light we commonly associate as heat? | In classical thermodynamics, temperature can be associated with the distribution of velocities of particles (not only molecules) - the wider the distribution, the higher the speed of particles on average, and the higher the temperature.
At the microscopic level, particles can lose some energy related to this motion and radiate it away. This can be the energy level of electron orbitals, rotations and vibrations of molecules, lattice vibrations in a material, etc. The spectrum of light produced by thermal radiation depends only on temperature. You can calculate it, and it just so happens that it peaks close to the infrared for everyday temperatures. For temperatures close to those near the surface of the Sun (\~6000K), it peaks at visible light. | 146 | 447 |
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Eli5: how were they able to pinpoint the exact cause of a rocket failure | I'm assuming now engine use real time monitoring systems and sensors. But how were early rocket designers able to determine what caused a rocket to explode like a raptured fuel line or something? Did they just guess? | Even early rockets had some form of telemetry that that transmitted live readings on the status of certain systems. You could use that data along with visuals (film and still photos) coupled with examining the wreckage, and you could usually get a pretty good idea of at least what major system was the problem. For example, if shortly before a rocket broke up, there was a voltage spike in the guidance computer and the rocket veered off course, you could reasonably trace that error to the circuit in the electrical system that provided power to the guidance computer. | 13 | 23 |
ELI5: Why can humans build up a tolerance to some medications but not others? | Edit: Thank you very much for the gold! I hope the comments made to this post were as helpful to others as they were to me. | Medications can work in a lot of different ways. One type that is prone to building tolerance are drugs that work in the brain by changing the strength of different chemicals. If a drug increases the effect of one chemical, then it works well at first, but the brain often adjusts one area to compensate for another. The brain might get rid of some of the receptors that are used by that chemical if it decides there is too much of it, making the drug less effective. Sometimes that just means the person needs a dose increase, because usually this balances out and you can still end up with more of that brain chemical than you had before, even after the brain tries to compensate for it.
This is also how drug addiction and withdrawal can work. If a drug causes your brain to reduce activity in an important area, then stopping the drug can leave not enough of it. This is really bad if that chemical helped your brain slow down when it needs to, and that's how withdrawal seizures can sometimes happen.
Other medications work in different ways that don't cause your body to compensate for them and are less likely to lead to tolerance. | 2,124 | 6,946 |
[Rick and Morty] isn't it a bad idea, as an assassin, to hand out business cards that tell people exactly where you are? | so in s2e2, the assassin "krombopulos michael" gives morty his business card that contains a real time map of where he is. isn't this kind of a real bad idea? i mean i'm no assassin but i wouldn't want my exact location to be public knowledge, especially when i'm out trying to assassinate people, and it does end up getting him killed. | Depends on how good you are. If you're so good your target can know you're coming and you'll still get the job done clean then it's good to get your name out there. If potential clients know about your exploits then you can charge far more for your services.
Furthermore, Krombopulous Michael just *loves* killing. Getting his name out there makes it far more likely somebody will find out about him and pay him to do what he loves. | 98 | 87 |
ELI5: Why do antihistamines make people sleepy? | It’s the time of year when the trees are shedding pollen to reproduce with other trees, my eyes and sinuses clearly do not consent to this airborne plant-bukkake. I’ve taken a little pink pill, and it does alleviate the allergy reaction, but it also puts me to sleep. I have stuff to do, this is annoying. | Histomines do a lot of different things for different parts of the body. In most of your body, it helps control inflammatory response (which causes allergy symptoms).
In parts of your brain, it regulates wakefullness.
Some antihistimes like benadryl are non-discriminatory antihistamines. This means they block the effect of histomines everywhere, including in your brain. The histomines that usually keep you awake are now blocked and that makes you drowsy.
"Less/Non-drowsy" allergy meds have less effect on those histomines while still being effective against the rest that cause allergy symptoms, making them effective but less drowsy. | 10 | 15 |
ELI5:Why hasn't Microsoft word made Times New Roman the universal font? | Fonts with serifs (the little embellishments on the end) are great in printed materials, but are harder to read on a computer screen. It's why most of the Internet uses sans-serif fonts, like Arial or Helvetica, and why Word switched the default font from Times New Roman (a Serif font) to Calibri (a sans-serif font) in 2007- Microsoft noticed that people had stopped printing out most Word documents and instead were reading them on a laptop or tablet. | 15 | 18 |
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ELI5: How do cargo ships have huge stacks of container vans and not topple over when facing rough seas? | I mean similar to this one
[https://images.unsplash.com/photo-1605745341112-85968b19335b?ixid=MnwxMjA3fDB8MHxzZWFyY2h8Mnx8Y29udGFpbmVyJTIwc2hpcHxlbnwwfHwwfHw%3D&ixlib=rb-1.2.1&w=1000&q=80](https://images.unsplash.com/photo-1605745341112-85968b19335b?ixid=MnwxMjA3fDB8MHxzZWFyY2h8Mnx8Y29udGFpbmVyJTIwc2hpcHxlbnwwfHwwfHw%3D&ixlib=rb-1.2.1&w=1000&q=80)
How does it maintain its stability when out in open water and it's facing rough waters? | Navigational officer of a large container vessel company here... Some of these other answers are pure speculation or straight wrong, sorry to say...
There are many thing together that help them not just fall off. The most important are loading pattern, ISO container, twist lock and lashing.
Loading pattern: we load the heaviest containers in the bottom of the hull and the top one is usually empty for various reasons. (Normally empty normal dry going to Asia and empty reefers going to Europe). Also taking ballast can help to bring down the center of gravity. The center of gravity is our target number and is calculated by advanced software with the information of the weight of the containers etc.
The ISO container: Today we mainly sail with 20', 40', and 45' containers. There are some odd sizes out there, mainly 53' US rail and a wider EURO container but don't know much about them. All containers build to ISO standard have there corner cast in specific places and sizes. And a minimum strength.
Twist locks: this is where the magic happens. Looking in hull, only 20' are stacked with a stacking cone (or hanging stacker, that can be put on from the pier) before locked with a 40' on the top. On deck, all are inter connected with both the container on top and below with twist locks. Here there different types, mainly a larger bottom base twist lock that also is stronger. All other uses normally manual, semi automatic or automatic twist lock. In the end all though work the same but you usually only have one type on a vessel. And the equipment belongs to the vessel.
Lashing: Lashing rods are put in place on most ships in two layers of containers. For the modern megamax ships they usually have 3 layers of lashing applied.
For many of the accident that have happened where it have been possible to investigate, either wrong or missing lashing (including any twist lock) or wrongly given weights from the sender making a heavy container on top, it will easier make the stack move and collapse.
Maybe not so ELI5, but feel free to ask any follow up questions
EDIT: To all of you kind strangers that have given me an award: THANK YOU... Especially the gold one | 5,184 | 4,004 |
Just how specific should my research interests be by the time I apply to grad school? | I've been working in labs with the goal of going to grad school since my freshmen year and since then I have also worked on several independent research projects in psychology. I am applying to social psych programs in the fall and I am just a little concerned that my interests are a little too broad. I have narrowed down my interests to a hand full of topic areas within social psychology and I know generally what I want to be researching. However, if someone asked me point blank "What study would you run if you could do it tomorrow?" I wouldn't know what to tell them.
TL;DR Applying to social psych programs in the fall. I've narrowed my interests down to a small set of topic areas but I still don't have a running list of specific project ideas, specific research questions, and study ideas. Is this too broad? | It's good to have a fairly specific idea of what you'd like to do, and even to be able to propose studies you might consider working on, but it's not necessary and in fact it can hurt you in the long run to be too inflexible about that. The reason is that your research will not be solely dictated by your own interests, but by the interests of your advisor, other collaborators, current research questions in the field you work in (which you won't have a good handle on until you read a couple hundred papers, probably), and what you can get funding for.
As others have said, focus on finding a professor who works on things that you find interesting, and apply there. Your interests are going to change anyways, you almost certainly will not end up doing your PhD on what you thought you would when applying (although it will probably be related to that to a decent extent). | 12 | 17 |
ELI5: How do popular social media apps become popular when they start out with 0 users? | Take snapchat for example, you would think people would only use it when a sizable portion of their friends are using it too which explains why it is popular now, but how do people launch such things that are compelling for people to be the first people to "use" them before they spread? | usually an app will be tested by a group of people who the app is targeted at and the developers will see how they use it and then try to cater it towards that market of users. once they know exactly what people want from the app/social media its entirely about marketing. getting the word out there, tell your friends about the app, they tell their friends, the userbase grows. | 101 | 336 |
I'd like to be recommended some authors which are not depressing. | Although it wan't all philosophy, I've read some Sartre, Schopenhauer, Kafka, Cortazar... to name the most influential to me.
I think that such obsession with existentialists and pesimists has really affected me in a bad way. I went from midly depressed for about a year to severey depressed, suicidal and very anxious. While I don't blame these people exclusively, their visions of human existance have been damaging to myself and have restrained me from enjoying life without analyzing how meaningless everything is.
I won't further develop my problems but I thought some context was necesary. I'd like to know about interesting and thought-provoking authors (and books too) which make life seem beautiful and worth experiencing.
Maybe its a wierd question (and stupid, probably), but I'd appreciate that you abstain from hateful and openly disrespectful comments. Thank you all in advance. | Thomas Nagel writes with a clarity that masks serious depth. Get a copy of *Mortal Questions* and enjoy yourself.
I also recommend seeking help from a therapist or psychiatrist if you are still depressed. | 12 | 24 |
An interesting subject for a ONE day class for high schoolers to get them excited about economics? | Hi all,
I'm currently teaching English in Europe for the year, but because I studied economics in college, the social studies teacher here wants me to give an economics class. I'm looking for a subject that will be easy enough for them to grasp while being entertaining and engaging. Any ideas?
Thinking about a game where the students get to see some lessons in competition, or perhaps some easy game theory stuff. What do you think? | Oftentimes game theory is the way to go in these instances. A repeated game prisoners dilemma is a great way to get some interaction going:
Divide the class up into groups, and tell them the rules of the game. Make them play about ten interations allowing for in-group discussion, tell them to write down the sequence of tactics their group used, and either play against the same group ten times or cycle so that they play a different group every round (in which case every group's strategy against another group has to be publicly announced per round) . Then get someone from every group to write down their Total Points on the board and their chosen strategy sesuence. Discuss optimal strategies and let them guess and think about it. Introduce Nash equilibria etc.
You could also discuss auctions by running first price auction experiments:
Let people write down their name and birthday on a piece of paper and set their maximum valuation for the auction as €(MM+DD) ( months and days from their birthday). The money they stand to gain for any auction is then equal to their max valuation minus their bid, if they win. So let them write down a bid for an auction with 1 random classmate, and one for an auction with 2 random classmates. Put the pieces of paper in a bowl and start making the pairs, followed by triplets. Determine who won the most money in the end.
You could then talk about the dangers of overbidding and underbidding. Let them suggest alternative rules to fix these problems. Then you could Bring in the concept of vickrey auctions/second price auctions or English auctions. | 43 | 69 |
ELI5: It is said that time gets slower and slower near a blackhole. Does this mean that inside the blackhole there is a point where there time does not exist at all? If something got sucked into that point, would it stop existing completely? | In GR you have to distinguish between the
1. The time a person at point X observes passing at a point Y remote from them and
2. The actual proper time experienced by a person at point Y.
From the perspective an observer outside the event horizon of a black hole time seems to stop at the event horizon. Nothing is ever seen to actually enter the black hole. [This is because the way a person at X observes things changing and happening at point Y is by receiving messages from point Y. The gravitational pull near the event horizon makes it take longer and longer for light to crawl out of the strong gravitational pull. At the event horizon the pull is so strong that light is making no forward progress. From the perspective of someone riding the photon out of the black hole it is like swimming against a strong current, the universe is falling back into the black hole as fast as they can swim out. Hence from X's perspective nothing enters the event horizon... because he can't see it happen.]
In reality, and from the perspective of a person falling into the black hole they do in fact pass through the event horizon and reach the singularity in finite time. | 250 | 292 |
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[Marvel Comics] How Advanced is Tony Stark's Tech Compared to the Rest of the Universe? | Including, but not limited to the Endo-Sym armor, the shiny new Model 52, and larger constructs like Sol's Hammer.
1) How does it compare to our universe
2) Compared to the rest of Marvel Comics earth
3) Compared to alien species like the Badoon, Shiar, Kree, Skrulls
4) Compared to DC Earth | > How does it compare to our universe
He could revolutionise almost every aspect of our lives, from prosthetics to energy generation, to medicine.
> Compared to the rest of Marvel Comics earth
Near the top, but still gets edged out by Latverian and Wakandan tech
>Compared to alien species like the Badoon, Shiar, Kree, Skrulls
Not even close.
>Compared to DC Earth
Near the top, but some tech probably beats him (probably because he doesnt really care about that scientific field) | 38 | 64 |
[star trek]why are most of the big fish in the galaxy (aside from the Borg) only a few thousand years old, warp capability wise? what happened to the races that were prominent in the milky way millions of years ago? | It is hinted at times that races or ensembles of races that become *too* advanced will become essentially "invisible" for less advanced races.
For instance the Q became incorporeal, all-powerful extradimensional entities, the "prophets" inside DS9 wormhole live outside time itself, the Fluidic Space is possibly is a pocket dimension created by Species 8742 itself, and so on. Even the Federation from the 29th century is so involved in time travel shenanigans that they already look kind of "detached" from normal life in the universe.
So, what the Federation normally sees, and what has any consequence or represents any concern for them, are other races that are about in the same window of technological and evolutive development. It's like how ants will perceive just other species of ants and other insects crawling over dirt, almost all the time completely unaware of - say - a gigantic, incredibly more complex and intelligent human observing them from above. The only times that they "perceive" the human (and in a rather incomplete way) are when he accidentally stomps their anthill or starts to burn ants with a magnifying glass for shits and giggles. | 69 | 52 |
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Are there any notable "essentialist" philosophers? | I've often heard claims that can effectively be translated as "essentialism is dead". Is this true, or does essentialism still have respectable defenders? Specifically, I'm looking for philosophers upholding an essentialist worldview, as opposed to a more existentialist one. | Essentialism has seen a revival in modern philosophy of science with the 'New Essentialism' movement. Brian Ellis has written several books on this topic, eg: *'The Philosophy of Nature: A Guide to the New Essentialism'* and *'Scientific Essentialism'*. David Odenberg's *'Real Essentialism'* may also be of interest to you. | 14 | 45 |
ELI5: How do we know whether an alternate medicine works or not when there are people around us who claim that their disease was diagnosed and cured by it? | I specifically mean Ayurveda and homeopathy here. They say that Ayurveda has cured cancer without any nasty side-effects of chemo. We know that these alternate disciplines don't have proper diagnostic methods for most of the diseases because there were no microscopes or MRI equipment back then. Then they say they didn't need all those stuff and they diagnosed diseases just by checking your pulse or whatever. Doctors and scientists, please help me. Thank you very much for your comments and replies. | To determine if a certain type of treatment works, it must produce better results than placebo.
The confusion begins because placebo works, and people feel better with just taking placebo. Same as some people get better when taking alternative medicine. However if the number of improved patients is the same as the number that get better with a placebo, the treatment remains in alternative category.
That's how you can understand many stories of people getting better. | 6,327 | 8,060 |
[Warhammer 40K] The Inquisition Vs The Adeptus Arbites | It seems to me that the roles of these two organizations overlap somewhat, with perhaps the deciding difference being accountability — Arbites do actually follow laws and codes and consider things like legal precedent and whatnot in their actions.
Despite their reputation, the Arbites also has investigative ranks, such as detectives who investigate possible crimes as well as chasteners who extract information from suspects.
The Inquisition focuses most of its efforts inward, effectively trying to identify and destroy covert incursions that obviously already run afoul of Imperial law.
For instance, the black market trade of xenos artefacts will attract the ire of the Ordo Xenos (or Ordo Hereticus) just as it would the Arbites.
As well, at the highest level, a Judge of the Arbites holds nearly the same powers as an Inquisitor.
So why are there two organizations? | Arbites are law enforcement, their duty is vigilance in ensuring life goes according to Imperial Creed. The job of Inquisitors is to deal with the enemies of the Imperium in a capacity beyond standard warfare. They root out cults, exorcise daemons, manipulate xenos, on a level far more complex and far reaching than the arbites. | 28 | 24 |
Eli5: Why is it easier to darken white paint than it is to lighten dark paint? | I remember in elementary school that I was mixing paints and to make grey, and I found that a small quantity of black darkens white super easily whereas even a 50-50 split of black and white leaves an almost black color. Is black paint more potent? Is there some kind of complicated color theory? | Paint color works by removing light, adding just a small amount of black pigment can darken white pigment a lot because it goes from absorbing \~0 light to more . But to lighten dark pigment you can only dilute the pigment. | 34 | 40 |
If electrons exist as a probability distribution then in what sense do they move around the atom? | Very likely some of my understanding here is wrong, so I'll try to clearly restate what I think I've heard physicists say.
1) Electrons exist as a probability distribution around the nucleus of an atom so that we cannot say where they are located but only give a likelihood of them existing in various places.
2) Electrons move around the nucleus at some speed.
These two conceptions of electrons seem to contradict each other. | I can think of two ways to explain this: the easy way and the hard way.
**The easy way:** imagine a spherical probability distribution. Imagine that you have a huge number of electrons distributed according to that probability distribution. Each of the individual electrons rotates around in some circular orbit, but the overall distribution of the electrons doesn't really change. It stays a sphere. That's kind of how electrons can be moving without their probability distribution moving around in space.
This analogy kind of starts to fall apart once you consider non-spherical probability distributions, though.
**The hard way:** You're probably used to thinking that the only "fundamental" information about a particle is its position, and that velocity comes from the change in the position over time. But in quantum mechanics, that's not true. The "fundamental" properties of a particle include not only the position, but also the momentum.^1 Momentum is not something that you figure out by analyzing how the particle is moving; it's a separate and independent quantity in its own right.
A quantum particle exists as a probability distribution over _both_ position and momentum. So when physicists say that electrons move around the nucleus at some speed, they're not talking about how fast the likely location changes. They're talking about the electrons' "intrinsic" momentum divided by mass, which is completely unrelated to the position.
Actually, when you look at it this way, the fact that a classical (non-quantum) object's velocity equals the rate of change of its position in time, and also at the same time equals its momentum divided by its mass, is kind of a giant coincidence. Not literally a coincidence, of course; the theory was designed so that it would work out that way. But it's a really interesting consequence of the fundamental assumptions of QM - it's something that has to be derived, rather than a definition as in classical mechanics.
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^(1) Technically neither of these is fundamental; they both come from the wavefunction, but that doesn't matter for this explanation. The point is that velocity is not just something you get from looking at how the position changes over time. | 13 | 32 |
ELI5: How does UV light sanitize surfaces? | UV light is a short enough wave length that it can penetrate into cells/viruses. When it does, it causes damage to the pathogen’s DNA. Essentially it gives pathogens supercharged cancer. It damages bacterial/viral DNA so badly that the cell can’t replicate and dies. Which is why most UV sterilization protocols are a minimum of 15 minutes, sometimes up to an hour, to make sure enough damage is done. | 341 | 271 |
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ELI5: How does compression clothing work? | There seems to be a lot of data confirming that compression clothing (tights, socks, sleeves, etc.) improves circulation. But my understanding is that compressing blood vessels would inhibit circulation. How does this work? | It compresses the small capillaries and vessels near the surface, forcing/diverting more blood through muscles and organs where it is needed.
You don't circulate more overall, but you are circulating more where it's needed. | 194 | 373 |
AskScience AMA Series: We're from the Pacific Northwest National Laboratory and we research pumped-storage hydropower: an energy storage technology that moves water to and from an elevated reservoir to store and generate electricity. Ask Us Anything! | We are Dhruv Bhatnagar, Research Engineer, Patrick Balducci, Economist, and Bo Saulsbury, Project Manager for Environmental Assessment and Engineering, and we're here to talk about pumped-storage hydropower.
"Just-in-time" electricity service defines the U.S. power grid. That's thanks to energy storage which provides a buffer between electric loads and electric generators on the grid. This is even more important as variable renewable resources, like wind and solar power, become more dominant. The wind does not always blow and the sun does not always shine, but we're always using electricity.
Pumped storage hydropower is an energy storage solution that offers efficiency, reliability, and resiliency benefits. Currently, over 40 facilities are sited in the U.S., with a capacity of nearly 22 GW. The technology is conceptually simple - pump water up to an elevated reservoir and generate electricity as water moves downhill - and very powerful. The largest pumped storage plant has a capacity of 3 GW, which is equivalent to 1,000 large wind turbines, 12 million solar panels, or the electricity used by 2.5 million homes! This is why the value proposition for pumped storage is greater than ever.
We'll be back here at 1:00 PST (4 ET, 20 UT) to answer your questions. Ask us anything! | Let's say you get 1 GWHr from the grid to pump water uphill. How much energy would you be able to return to the grid when the same volume you pumped uphill comes through the turbines? What's the round trip efficiency? | 197 | 2,701 |
ELI5: How does reverse image search work? | I often see people on r/quityourbullshit calling out people and using a reverse image search as evidence. How does this work? | The other answers so far have been a bit over simplified so I'll try to go a bit deeper while still making it accessible.
It you have an image of a cat you can describe that image in a lot of ways. Let's assume we have a picture of Garfield and we have photoshopped the background to be black for simplicity. Some obvious ways to describe it might be "orange" and "generally curvey" (as opposed to a picture of gravel which might look "generally angular").
You can further describe the image as "has two half circles (ears) above a round region (head)" and "has two long skinny regions (legs) connecting an upper region (body) to a lower region (feet)".
You can get more detailed on each thing like "the non-black regions are about 90% orange and 10% black" or "the half-circles (ears) are 1/10 the size of the full circle (head) below them"
Computers are much less explicit than this since it is all done via an algorithm, but hopefully you can imagine a computer coming up with hundreds or thousands of these generalized image descriptions and associating them with an image.
Then when you upload a new image it looks at your image and describes it in this way, then finds images with similar descriptions. In some cases the descriptions will be practically identical: that is how it finds different sizes of the same image. In other cases it will just be close enough: those will be related images.
Furthermore we use metadata to associate it with specific words. With our Garfield example: the computer won't find anything in that image to associate it with the word "Garfield", but maybe a lot of people upload the image as "Garfield.jpg": the algorithm will notice this and start associating the word "Garfield" with those descriptions it generated. They also use nearby text on webpages (i.e. captions) to get descriptions. | 85 | 105 |
ELI5: What is the science behind Children who's parents are closely related end up being born with birth defects? | I really have no good reason to ask this other than i saw a article on king tuts birth defects and the fact that his parents were most likely brother and sister. | in order for recessive traits to be expressed (to show up), you need to have two of them; otherwise the dominant trait will be expressed. when parents are closely related, they are more likely to have the same recessive traits, increasing the likelihood that their offspring will inherit two of them. since defects are often recessive, they tend to appear more frequently in the offspring of closely related parents.
the moral of the story is that genetic diversity is good! | 115 | 115 |
CMV: If your goal is to limit your carbon footprint you should be buying old used cars and not new "eco-friendly" ones. | Buying hybrids because they're better for the environment really seems like a disingenuous action to me. If your main goal is to reduce your carbon footprint, then why are you supporting the manufacture of new products when used ones are still available?
The civics/geos/sprinters/metros of the 90s and early 2000s rival current hybrids with mpgs in the 40s.
A large portion of emissions generated through a vehicles lifetime come from the initial manufacture and transport too, so why wouldn't you just buy something that already exists and drive it till the wheels fall off? | Purchasing new hybrid and electric cars promotes the development of new eco-friendly technology. The people who bought the Tesla Roadster gave Tesla the capital to build the Model S. The people who bought the Model S gave Tesla the capital to build the Model 3. This support fuels innovation for the future. | 65 | 139 |
ELI5: How do commercial bread makers like Sara Lee and Pepperidge Farm get their loaves to turn out in a uniform size and shape every time? | Science and machines!
These companies most definitely have a research team on hand. They study everything about the product to make it the best they can. Chemistry, flour types, even yeasts and fermentation.This results in more controlled and better understood products.
The other half is factory bakeries. They mass produce their breads in machines. Because human hands have little to do with the bread making process, the product always comes out more consistent. | 293 | 272 |
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ELI5: What does it mean when a smoothie or other food product lists "natural flavors" on the ingredients list? | In the United States, "natural flavor" means that, to provide a flavor, a concentrated extract of the usual ingredient has been added. Let's say you've got strawberry candy--instead of adding strawberry, you can add an extract of some of the chemicals in strawberries that provide the characteristic flavor; that's a "natural flavor." The label "other natural flavor" means that the flavor added is not just from the thing the product is labelled as--in addition to strawberry extract, you'd be adding another natural extract (not from strawberry) that enhances or simulates the strawberry flavor.
These terms are regulated by the Food and Drug Administration. Note that the term "natural" here only indicates the ingredient was derived from a natural source, rather than being synthesized. | 85 | 202 |
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What’s something useful you’ve learned from your field that you think everybody should know? | I’m not a PHD or anything, not even in college yet. Just want to learn some interesting/useful as I’m starting college next semester.
Edit: this is all very interesting! Thanks so much to everyone who has contributed! | Physical and mental health are far, far more connected than people appreciate. The gut microbiome and systemic inflammation are huge contributors to our mental health. For example, gingivitis, a bacteria-caused inflammatory gum disease, has been associated with many mental illnesses as well as neurodegenerative diseases like Alzheimer’s.
Take care of your body– including your teeth. It is so, so important for your mind. | 369 | 265 |
How difficult would it be to create a watch party service like this? | I've been rummaging the internet looking for a service with the following functionality but have come up short, leading me to believe it's either difficult to make or monetize:
1. Must be able to stream synchronized video playback to group members, such as Netflix, Youtube, Vimeo, Prime Video, Hulu, HBO, or other websites with video.
2. Can also stream video originally from video files on a member's computer or cloud storage, and distributed potentially through a relay server if their upload speeds are too slow to keep it high quality for all members.
3. Independent options for volume and subtitles. One viewer may use low volume while another uses high, etc.
4. All members able to play/pause and seek the video and it remains synchronized on other member's screens.
5. 1080p quality. | 2 main areas of immediate concern: legal structure and operating cost.
There have been quite a few services targeting this in the last decade that have closed due to lawsuits regarding their hooking into other platforms.
1080p at a decent bitrate will be gigabytes per user per stream and if the point is to alleviate poor connections that transit will not be public. You would then go to a client to client distributed model and be using some form of udp mesh topography which is where things go from napkin sketch to a month of architecture design. | 16 | 19 |
ELI5: How do people design the save game feature in large/complex games? | The save game feature seems simple but it's mind-blowing how it can return the exact state of a game with all elements/events organised in the correct order. Can anyone explain how it works? | Games have flags (kind of a checklist) of all the possible action you need to do in the game (in the sense of "complete this quest", "find this object", "unlock this part of the map", etc.) And also a bunch of variables to indicate your location in the game, what equipment or item you have in each slot (+inventory).
The save will just be a backup of all those flags and variables and which state they were in at a point in game.
This is a bit of a simple answer and will vary a little depending on the type of game.
Bonus: this is how cheats work too. People will analyse game memory and find where these flags/variables are and offer you to edit the value. Like find the variable "health potion in inventory" so that you can add 99 of them if you like. | 630 | 679 |
ELI5: How do emergency rooms work? I recently went and was told the wait would be around 14 hours. Seems like a lot of people could die within that time range... | Emergency rooms work on a case by case basis. A 14 hour wait was for your level of need. A critical injury where death is imminent would take precedence over for example, someone breaking their arm.
They also try to give worst case scenario based on doctors hours, available staff, and the current list of injuries and estimated time for each type of injury.
Source: have numerous friends that work in emergency | 287 | 320 |
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ELI5: why does adding a proton completely change the properties of one element to another. | It it only because of the extra electrons? Do the protons actually do something? Does adding neutrons add any properties other than then possibility of a decaying isotope? I don't get how for example a proton changes carbon to nitrogen and all the properties than includes (solid to gas, black to colorless) | Two atoms will find their most stable positions relative to each other by how the cloud of electrons around them interact and this makes up most of their interaction under the conditions we find here on Earth. The number of protons affects the behavior of the electron clouds with more protons attracting more electrons.
All of the properties you discuss, such as the properties of their phase changes or coloration, are electrical in nature and largely come from the interaction of these electron clouds. For example, the color of a substance is a result of which wavelengths of light the electrons of a material will absorb, which is in turn a result of the density of the electron cloud around the nucleus, which is in large part a result of the charge of the nucleus which is dependent on the number of protons present. | 33 | 85 |
CMV: We are on our way to completely destroy forests and wildlife | To be honest i'm really making this post in hope that there's some optimism out there, but i don't see any.
In my native country (romania) i always heard since i was little about the illegal and legal logging that is going on, and apparently it's much worse for the amazon rain forest, papua new guinea, north korea and many more places. My view on this is basically that our ecosystem is being destroyed by big corporations for profit and that the only way nature will recover is when humans go extinct. | Wood can be and often is a renewable resource. In the EU considerably more trees are planted than are cut down, and forests are beginning to recover and expand. In the US virtually all paper and softwood comes from sustainable forests or tree farms planted exclusively for harvesting the wood once the trees are grown. Throughout the entire world, restrictions have been placed or are being considered on certain types of wood that are not sustainable and tend to be harvested through deforestation in places like the Amazon.
All this to say, things have already gotten significantly better regarding our treatment of forests, and we are on a trajectory towards completely sustainable lumber and paper. There are certainly still plenty of challenges ahead and there *are* a huge number of ecosystems that are currently being damaged for profit, but there's no reason to assume that's the only way things can go because we are already making significant progress on both ending and reversing that damage. | 16 | 24 |
What are typically the first problems of a new society? | Say a new city was built that was totally self sustainable. Over time what problems would inevitably come in to the picture eventually.
For example big cities obviously struggle with homelessness, crime and the like. But what I'm curious about is are there certain things that unanimously happen first or is it just completely random historically speaking? | property comes up a lot in hobbes, locke, and rousseau; specifically what right individuals have to land, how to earn that right, and how their right compares to that of the state over the land (Rousseau and Locke be loving labour, while Hobbes be all over the place on that sovereign power trip).
Early sovereigns would usually be in place to protect individuals' rights to land...and in this statement many questions arise that are answered differently by the three theorists.
edit: just remebered the city part....new societies don't really just pop up with self-sustaining cities, so it's hard to tell.
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ELI5: Can anyone explain why we have foods that start out on the shelf but than have to be refrigerated so they won't go bad? | Foods like:
Ranch
Mayo
Ketchup
Etc.. | Most foods with "refrigerate after opening" have been vacuum-sealed or canned in order to kill off harmful bacteria, or heated and the package filled with nitrogen (or inert gas) in the case of dry foods.
As soon as the container or package is unsealed, it's exposed to oxygen and all the dirt, spores and bacteria contained in our atmosphere once more, and so the decay, fouling, molding and/or other such degeneration processes start back up immediately. At that point, you put it in the fridge or things like mayonnaise will do what they do best; go completely rancid overnight.
Effectively, the packaging techniques allow us to temporarily pause the food's expiration, until we've opened it. | 13 | 15 |
What keeps the moon in orbit according to general relativity? | As far as I know, gravity is not being treated as a force in GR, but is the curvature of space.
I understand the concept of a black hole bending spacetime so much, that the straight path leads into the singularity, thus capturing photons.
But how does the moon's orbit work?
I know pictures like [this](http://i.space.com/images/i/1346/i02/051116_vortex_02.jpg?1292263821) draw an analogy to bent surfaces. In order for a sphere to stay in orbit, however, there has to be some force drawing said sphere towards the lowest point of the surface, doesn't it? The centrifugal force has to be equivalent to the force "downwards".
But if gravity is not actually a force, how does the moon stay in orbit? | The mass of the Earth causes some curvature in space-time. Any mass causes curvature; for smaller masses the curvature is smaller, but it's still there.
There is no gravitational "force" in general relativity, rather, things just keep moving on the "most straight curves" which are called "geodesics". This is the curved spacetime generalization of Newton's first law of motion; moving on a geodesic is the closest thing possible to moving in a straight line.
Around a spherical mass like the earth, some geodesics are roughly closed cycles, meaning that a body which starts off on one of those cycles will end up at roughly the same place it started with approximately the same velocity but at a later time. These closed cycles correspond exactly to orbits.
For large distances from well-behaved masses, GR is asymptotically the same as Newton's law of gravity in a fixed flat spacetime. | 20 | 38 |
ELI5: How can someone define the age of something? (mummy, dinosaur's bone, etc) I just read an article "Baby bird discovered in 99-million-year-old amber" | There are various dating methods, and they can be checked against each other to make sure the results are consistent. The age of fossils is usually determined by radiometric dating. How it works basically is that there are a bunch of elements that occur on Earth naturally, and a bunch of elements, or different isotopes of certain elements, that only exist on Earth as a result of one element radioactively decaying to the other element. The decay always happens at a constant rate. Based on how much of the source element and the result element are present in the sample, we can evaluate how old it is. | 12 | 23 |
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[Star Trek] Can the teleporter be used to reconfigure the object being teleported? What are the limits? | The food replicator in Star Trek is a sort of teleporter, and it has recipes on how to assemble the source material to fill an order. Therefore Star Trek teleporters can manipulate data used during the teleportation process. So what are the limits?
Can I use the teleporter to perform surgery and remove a tumor? Can I use it to genetically combine two animals into a chimera? Can I use it to perform plastic surgery and give someone a face lift? Can I use it as a weapon during a war and teleport enemy soldiers, but reconfigure them into blocks of carbon?
I'm not very familiar with the Star Trek universe, so examples in-universe are appreciated. | Allegedly, replicators are “molecular resolution,” while the personnel transporters are “quantum resolution.” The former are sufficient for rearranging feedstock into food and equipment or whatever, but the latter is necessary for living beings. Quantum resolution is so detailed that it’s not feasible to store the pattern for a complete person; they’re broken down and transmitted via a “pattern buffer” bit by bit. The idea is that you’re scanned, you’re beamed, and the pattern is never stored.
However. The transporter also supposedly reads the pattern and filters out known contagions and (I think at least sometimes?) weapons. It seems like it would be conceivable to swap a body part or something, but maybe there are limits to inserting a new pattern with precision in the brief time it flits through the buffer. It’s not normally used for surgery.
Transporter accidents have certainly done stuff like accidentally merge two characters or duplicate characters or even cross the boundary between universes. | 46 | 77 |
ELI5: How is information and data stored in pieces of metal and green boards? | A bunch of 1s and 0s (that are specifically arranged to describe the information) are stored in the form of anything that can be in one of two states, like a light switch. It's either up or down, on or off, 1 or 0.
So the easiest example to explain is CDs. The bottom of a CD is etched by a laser with tiny little dots, or, tiny little spaces with no tiny little dot. Then, an electronic device like a CD player is made so that it can see the arrangement of dots or no dots, and turn that information back into the form that humans can understand.
Other forms of data storage work the same way, just with different methods of storing and retrieving the 1s and 0s.
to go a little deeper and explain how something can be 1s and 0s... take the alphabet.
If you were to say 00000001 is A, and 00000010 is B, etc, and you had a wall of light switches and lights that went on and on and on, you could write messages by having the right lights on or off.
Modern flash memory does the same thing, except the wall of lightbulbs is actually an insane amount of tiny transistors that push electrons around to indicate 1 or 0. | 56 | 41 |
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ELI5: Is intelligence entirely determined in the early stages of life or is it something that can change later on? | Whenever I read about influential scientists and mathematicians, I notice how their upbringings had a similarity: their curiosity and intellects were all nurtured as children. Do people farther down the road of life still have the ability and potential to grow their minds to reach the same heights? | Your genetic code mostly determines how your brain will form and develop, but environmental factors (nutrition, injury, etc) during the growing process play a big part in this. But most healthy brains end up similar to each other in most ways, so barring disabilities, that's not that important.
Most people have the capacity to learn whatever they want, they just need to put effort into learning. Therefore, capability for knowledge is common among people, but actual knowledge is a consciously acquired thing. | 23 | 37 |
CMV: We would have a more informed populace if schools prioritized statistics and probability over other areas of math | **Constraints**
First, my primary education in the US public school system in the pre-Common Core days. I took a quick glance at the [Common Core curricular content](https://en.wikipedia.org/wiki/Mathematics_education_in_the_United_States), and it looks very similar to what I had to learn. My understanding is that before CC, curricula were more varied by state, but for the sake of keeping the discussion focused, I will be focusing on CC Standards in the US.
Second, I majored in a STEM field that was fairly math-heavy, and while I don't believe that much of it is useful to me today, I'm not ready to make this claim for all majors. So I will focus on primary education and leave universities out of this.
**My View**
As per CC Standards in the US, basic math education consists of Algebra I, Geometry, and Algebra II. College-bound students are also offered Pre-Calculus, Calculus, and "other optional mathematics courses \[...\] such as statistics or business math".
One of the age-old questions that students ask is, "When are we ever going to use this?" While I'm not here to argue that these skills are useless in adulthood, I think they are vastly overrated. [This article](https://www.forbes.com/sites/jamesmarshallcrotty/2012/12/06/when-am-i-ever-going-to-use-algebra-the-real-world-utility-of-classroom-learning/#36fe2bfd6bfc) has some examples of ways we use certain subjects every day, and some of them, like using algebra when calculating purchases, are very reasonable. However, to reference another one of its examples, I'am not convinced that one needs a solid understanding of calculus to pay off their debt, especially with the prevalence of apps and online calculators today.
What I do believe, is that we benefit from a solid understanding of statistics everyday. Gaps in people's knowledge of statistics have long been exploited by advertisements, political campaigns, and unscrupulous con artists. Given the tumultuous current events right now, a fundamental grasp of statistics is necessary to make sense of two or more conflicting sources, particularly when they present conflicting interpretations of the same data. Without knowing how to determine statistical significance of the numbers we see in the news, or in commercials or opinion pieces, it is very easy to fall prey to someone's agenda, and this may result in wasting money, spreading misinformation, or making life decisions based on faulty, inconclusive, or erroneous data. If these decisions concern one's health, they may even be life or death decisions.
At the very least, I think the emphases on statistics and calculus in the American school system should be swapped, and an leaning towards spreading it out over multiple years, de-emphasizing the importance of Geometry, Algebra II, Pre-calculus, and Calculus in favor of a more rigorous statistics education. I am not ready to say that it is more important than Algebra I.
**What would CMV**
A convincing argument as to why Algebra II, Geometry, Precalc, and/or Calculus are more important for day to day life than statistics, or an argument as to why statistics are not as important as I have claimed.
**What would not CMV**
Anything about standardized tests. I am operating under the assumption that tests should resemble education, and not the other way around (it doesn't always work that way, but that's a discussion for another time).
Anything differentiating probability and statistics. While they are often bundled together, I realize I didn't state that clearly. But from here on out, let's lump them in together as being equally important.
I also think that for the sake of "not getting duped" (to summarize what I wrote earlier), understanding the rules of logic and critical thinking are just as essential as statistics, if not more so. This should be taught alongside probability and statistics, but for now, I want to focus on the importance of prob/stat vs. algebra/geometry/precalc/calc. | The reason why Algebra II, Geometry, Precalc, and Calculus are more important to do first is that _they are prerequisites for Statistics_. You fundamentally can't do Statistics with any sort of continuous random variables without either Calculus or lying extensively to students about what terms mean. For example, the expected value, which is a central concept essential to basic statistics, literally _is an integral_ (in its simplest formulation) and can't be properly explained without integration. | 64 | 159 |
Does logarithm of negative numbers have any meaning? | I know that there is no real solution to logarithm of negative numbers, but I understand one could define log of natural number using the Euler's identity, as exemplified by ln (-1) = (pi)*i. Does this kind of definition have any physical/mathematical meaning at all, or is it useful to solve certain problems? Thanks a lot | Physicist here, we use complex exponentials when representing the amplitude and phase of a wave of light. It is based off Euler's formula and can help make solving problems involving light much easier to calculate.
When finding the phase of the light we have to take the logarithm of a complex number. In the special case it is a real negative number the phase is simply pi +/- 2(pi)n as the phase is cyclic.
In the more general case we use the Euler formula to find the phase given the wave state or vice versa. | 30 | 90 |
Does probability still exist if the results are already determined? | Im sorry this is a slightly confusing title, but i will try to explain with an example:
There are 2 boxes, one of them contains a prize, the other one is empty. You have to guess which one has a prize in it, this means you have a 50% chance of guessing it right every time.
After you say "the box on the left", from an observer's point of view (who can see what's in the box), you either have chose right and have a 100% chance of guessing correctly, or you chose wrong, and have 0% choosing correctly. But from the player's point of view, you dont know if you got it right or not, do you still have a 50% chance to get it correct, even if the answer if already determined? | One way to consider this is that probability is a measure of the uncertainty that a person has in the outcome. From your point of view, you have no information and the chance is 50%, but from the point of view of someone who knows where the price is, there's no uncertainty.
Or rather, the entropy of the results you expect is related to your uncertainty. You have 1 bit of uncertainty and the person who knows the answer has 0 bits. | 56 | 124 |
ELI5 - There are gases that destroy the ozone layer. Shouldn't there be a compound out there that had the opposite effect? | The title's the question. I've thought about it for some time now, but I can't find an answer. | The fundamental issue is energy. There's more energy stored in 2 O₃ (ozone) molecules than in 3 O₂ (oxygen gas) molecules.
So a chemical that can turn ozone into oxygen can do it over and over again, liberating energy as it goes. Kind of like how you can burn down a house using just a single match: a single chlorine atom, for example, can destroy a hundred thousand ozone molecules.
On the other hand, turning oxygen into ozone requires *depositing* energy. Lightning and sunlight can do this, which is why we have an ozone layer to begin with, but any chemical that did it would have to be supplying the energy by destroying itself, and so could only do it once--*not* a hundred thousand times. | 50 | 27 |
ELI5: Why my leg (or arm) can randomly twitch for no reason. | Not just a small twitch but like when your leg randomly flinches upwards like an inch, then return back to relaxed position? Or am I the only person this happens to?... | The basics you probably know is that you are made of cells, tiny building blocks of life that are tiny bags full of chemicals. The cell walls have a bunch of tiny holes (channels), a lot of which only let certain kinds of chemicals pass through. Your body uses a whole lot of different chemicals to do a lot of different things, but many of them have very specific jobs.
For muscles to move, they need to be signaled by your nervous system, which usually happens when signals are sent from the brain. A signal will travel from the brain to what's called a motor neuron - the last piece of nerve tissue before the signal is then passed to the muscle cells.
Within a cell, there's some fancy equipment to make sure the right amount of any given chemical is on the inside of the cell compared to how much is outside. The nerve cells (neurons) work by waiting until they receive input, and then a chain reaction happens that allows a bunch of extra chemicals to flow through the cell wall, upsetting the normal balance. It returns to normal pretty quickly, though. This cycle is called an "action potential" or a "spike." (The chemicals that flow are all electrically charged, so we can read this as a change in local voltage if we stick an electrode right next to it.)
Sometimes by happenstance the chemicals get unbalanced around one neuron or a group of neurons, enough to initiate an action potential. These neurons can activate neurons that they connect to, sending a small group of spikes to their neighbors. If the random impulse isn't close to muscle it just dies out, but if it's pretty close, it will hit the motor neuron (or maybe more than one), which will in turn send spikes to a set of muscle cells. Then those muscle cells go through some stuff and end up twitching!
edit: added a couple words for clarification | 21 | 45 |
ELI5: Why is the Mona Lisa considered to be such a masterpiece? | Just visited the Louvre and was underwhelmed. It doesn't seem much different in quality to the paintings around it, to my untrained eye. | Along with special techniques with composition, The Mona Lisa gets a lot of its attention from its historical background, or more specficially, the lack thereof.
- Most paintings at that time took several months at most to complete. The Mona Lisa took 10 years. Why did Leonardo da Vinci take so long?
- It is said that da Vinci was working on it once, and he saw something in the painting that scared him and made him hide it for 10 years. If the story is true, what did he see?
- At that time, paintings had elaborate reasoning behind them. So why did da Vinci paint Mona Lisa in the first place? And why is she smiling so smugly?
- Continuing on that line of questioning, what is up with her background?
- Why does she have extremely faint, if any, eyebrows?
- And who is the woman painted, anyway? | 23 | 26 |
[Metroid] Why not just totally destroy planet SR388? | So the Chozo created the Metroid species to hunt the X-Parasite. Why not just totally destroy the planet instead? Why create another highly dangerous life form?
Surely they have the weapons technology to glass the planet. I think that would be the surest way to wipe out the parasite. | The Chozo valued cosmic balance and harmony with nature. Destroying an entire ecosystem would be an atrocity. It's so much more elegant to introduce a single engineered species into the ecosystem to correct it. They probably viewed it as a work of art. | 31 | 34 |
Came Across a Quote Today from Reagan | "Inflation; That's the price we pay for those government benefits everybody thought were free."
How much truth is there to this? Did the government know this was going to happen? | Inflation has many contributing factors. Attributing it only to government spending (as implied here through issuing debt) is incomplete and inaccurate. There are many countries with small government benefit programs experiencing inflation today. As well there are many historical examples. Monetary policy, external price shocks (e.g. OPEC formation), supply disruptions (e.g. wars, disease), or other things have been the primary contributor to inflation shocks in the past.
This is a quote with some seed of truth (government spending can contribute to inflation) but is misleading by implying that's the only cause. | 41 | 22 |
How to know if someone produces good research? | Ideally I'd have the skills to identify good research but I'm still in my undergrad so that's a skill I'm still developing.
Is there a fast way of knowing someone produces good research in a certain field? Especially identifying a "rising star".
I tried looking at number of citations on Google scholar but I don't think it's very accurate since older researcher are likely to get more citations. And some PIs produces 40+ publication a year so they're likely to get more citations.
I could ask my mentors but they're likely going to suggest people that they know personally and/or only in their subfield of subfield.
And using their schools seems very snobbish. | This is a question that is hard to answer, because everyone has different metrics for "good" research, and you never know what direction research will take you.
That being said: there are usually conferences in which you will see topics that generate great interest to the community. It is often hard to go for an undergraduate but they are certainly worth your time to get a "feel" for the community.
Also, you can look at agencies that fund early career awards, like NSF CAREER (or even better, PECASE) or the NIH DP2 awards. These awards are considered for "rising stars" at least by their funding agencies.
More important that any particular qualification of good research, perhaps it be best to take a deep look at the fields YOU'RE most interested in. A passion is a passion and you can usually find good problems if you're inquisitive and creative enough. | 14 | 18 |
ELI5: Why does water make some things more slippery(like condensation on glassware) and some things less slippery(like wet jeans)? | It all depends on the material you are working with. Water is actually a very polar substance, it's why it's a terrible lubricant. Meaning it has a high likelihood of being attracted to and sticking to most other materials, including itself. The one big exception is non-polar materials, which includes most glass and plastics. In these cases the water is trying not to Interact with the surface to the point where it will bead up and roll off. | 342 | 715 |
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ELI5: How does the seatbelt know that it's being pulled fast (crash) and stop extending but still extends when pulled slowly? | true eli5: imagine standing in a very small room. Relax your arms and turn slowly. Your arms will stay close to your body. Now turn fast. Your arms will move away from your body and hit the walls slowing you down. | 7,295 | 8,797 |
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Is the human body capable of fighting both viruses and bacteria with the same effectiveness? | So I can recall several times in which my GP has highlighted the fact that for a virus such as the flu or the common cold, you just need to let your defences take the wheel and fight it off. For cases in which the body has to fight a bacterial infection (pharyngitis - strep throat) and in which you typically are prescribed antibiotics...I wonder if you don't go through such treatment whether the immune system is capable to fight off the infection with the same effectiveness as when fighting a virus.
Apologies if it's a silly question, I come from a culture and age in which antibiotics were prescribed too easily IMO.
Thanks! | Depends entirely on the particular virus or bacterium. Some are handled well by the immune system, some are not.
I think the real difference here is the availability/relevance of antibiotics vs. antivirals for treating certain symptoms. There are some situations where you can use antiviral drugs, but in many cases it isn't considered worth it (or there simply isn't an effective drug available). But we're also coming around to the fact that antibiotics probably should not be prescribed as often/freely as they have been historically. | 74 | 132 |
CMV: Waiting for a teenager to turn legal so you can subscribe to their Onlyfans is damn creepy. | [Here's the link if you want to see the whole thing for yourself.](https://twitter.com/BhadBhabie/status/1377717608225460225). (Maybe by now some of them could have deleted their tweets, if that's the case I'll upload screenshots I took yesterday) The girl saying herself she was 'tired' of people asking is already setting off alarms, but then scroll down to replies and people are actually talking about waiting for 5 years for her to make an Onlyfans? When she's just now 18? and I don't know whether those people don't know what they sound like or they straight up don't care, but it's insanely creepy either way. | First of all: is this really a topic you want to change your opinion is?
If the answer is yes: would you agree that maybe there's some specific cases where it's less creepy? because of course a 50yo seeing a 13yo and thinking '5 years to wait" is **awfully creepy** but if a 18yo follow on tiktok a 17yo girl posting dancing videos who said that when she is 18 she will start posting nudes and is pretty excited about the idea, isn't that way less creepy? | 38 | 130 |
ELI5: Why do sugary solutions get sticky as they dry but salty solutions don't | Source: Have dropped a variety of IV solutions. | Sugar will form hydrogen bonds with all sorts of compounds. This means it can be "sticky" and hold lightly to things while still being in solution.
Salt, however, will simply dry as a crystal and just be either in solution or out of solution, and can't interact very strongly with ions already in solution. Thus, it is not terribly sticky and will just make your hands a little salty. | 113 | 270 |
ELI5: What are work unions and how do they help employees? | In the recent Activision/Blizzard controversy I've seen the word union being thrown around a lot. Whilst I understand it is beneficial for employees, I just dont understand how it works. | A union is basically a club workers join that negotiates on their behalf with the company they work for and provides benefits for members like help finding a job, professional advice, arbitrating disputes, running pension plans, or providing monetary support.
Workers who are in a union can use their "collective bargaining" power to get better wages and conditions at work because all the workers negotiating as one unit has a lot more impact than a thousand people all trying to negotiate individually. | 69 | 40 |
[Dune] How would events have played out if Paul was born female? | Lady Jessica was ordered to bear only girls to Duke Leto, with a view to future marriage into House Harkonnen. How would the events of Dune have gone if she had obeyed? Presumably the emperor would still have set his trap for House Atriedes on Arrakkis. | An interesting question. There are many possibilities:
If the Reverend Mother was telling the truth that she wanted a marriage and alliance between Harkonnen and Atreides, then the Bene Gesserit may have "encouraged" the emperor not to go through with his trap.
Alternatively, Lady Atreides may have been taken away from Caladan to a Bene Gesserit school, keeping her safe from the Arrakis trap. From there she could have been married to Feyd-Rautha Harkonnen as an offering to stop the slaughter of House Atreides. Or the Bene Gesserit could have let the slaughter continue and kept her theirs, house-less. She could then seduce Feyd-Rautha some time later. Marriage was not required to conceive the Kwisatz Haderach, only one night of drunken passion with a "nameless girl".
Of course, it's entirely possible that Lady Atreides might have failed the test of the gom jabbar. Part of what allowed Paul Atreides to pass was the Mentat training he'd been given from Thufir Hawat. An Atreides daughter may not have recieved the same training.
If Lady Atreides did go to Arrakis with her family and fall into the trap, her first interactions with the Fremen would have gone differently. She would likely have ended up a wife of Stilgar or even Jamis. From there she could possibly have led (either overtly or from the shadows) the rebellion against Beast Rabban. But without the same abilities of foresight that Paul had, it's unclear how successful that rebellion would have been.
Still, the Baron Harkonnen was setting Beast Rabban up for failure against the rebellion, in order to be replaced by the savior of the people, Feyd-Rautha. So it's *also* possible that the Lady Atreides could have wed him, ending the Fremen rebellion and fulfilling both the Baron's and the Bene Gesserit's original plans. | 20 | 15 |
ELI5: The new theory about the beginnig of the Universe | I read about this new theory about the beginning of the Universe and I can not wrap my head around it. Could someone please explain it in simplier terms.
http://www.universetoday.com/104863/goodbye-big-bang-hello-hyper-black-hole-a-new-theory-on-universes-creation/ | We have recently been taking the idea of there being more than the 3 real and one temporal (time) dimensions seriously. Doing so has provided possible answers to some questions about the universe and matter, expressed in maths that uses multiple dimensions. The only problem is getting a human mind that has lived it's life in 3.1 dimensions to comprehend it. Whether these answers will stand up is one question, but, for the moment, it looks like there are more dimensions than length, breadth, depth and time.
Now, think of a sphere. The surface of a sphere is a 2 dimensional shape. You can live most of your life thinking of directions on the spherical earth in two dimensions. You can go two miles east, two miles north, two west then south, and you'll end up in the same place. It all works.
It happens to be wrapped around in a third dimension. So we have a two dimensional surface wrapped around in a third dimension.
Now what if you had a 'universe' that had 5 dimensions - length, breadth, depth, time, and wibble. Imagine a black hole forming in that 'universe'. What, you can't? Well, to tell you the truth, neither can anyone else. But what we can do is create maths that models it, that acts like it would. The 'surface' of that black hole, the event horizon, would then be a 5 dimensional sphere - a 4-dimensional surface (or space) curved around in a 5th dimension. What does that maths tell you about that 4-D 'surface'?
Turns out, it gives you something that is surprisingly like what we have detected about the start of our universe. This is really interesting. Is this what our universe really is? Possibly - probably not. But it is interesting. | 15 | 15 |
ELI5: What causes us to get bags/dark circles under our eyes when we are tired? | Dark circles are just the blood that is circulating around your eyes showing through the skin. The skin under the eye is very thin, so subtle changes can cause these circles to appear. In essence, there are three main reasons why this can happen:
* your blood vessels dilating (low blood pressure). this can be because of inflammation such as with allergies or rubbing. when you have an inflammatory reaction, your body releases histamine, which causes a reaction to get as much of your immune cells to the area as possible. this will cause more blood flow, resulting in a lower blood pressure and dilated blood vessels. this means more of them show through the skin. it can also be because of heart medication or erectile dysfunction drugs which work by causing veins to expand. being tired will cause dryness and irritation around your eyes, which will lead to an inflammation similar to an allergic reaction, causing more of the darkness to appear, especially if you irritate the area more by also rubbing it.
* your skin getting pale. if you are not getting enough sleep, anemic, or dehydrated, your skin will become paler and that will show more of your blood vessels through your eyes.
* your skin getting thinner. this is mostly the cause of dark circles when you age.
Bags are caused by areas under your eyes filling up with water or fat. This is essentially a secondary effect of inflammation. Expanded blood vessels will cause fluid to accumulate and pool, and leak out of your blood. This is normally beneficial because the fluid will have immune cells in it that will help fight an infection or irritant. This is why injured areas will be red, hot, and swollen, but in this case it will cause these bags. In addition, rubbing your skin (as is common when being irritated) will exacerbate this, essentially mechanically squeezing even more fluids out of the blood vessel. | 4,193 | 9,366 |
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What happens to electricity pushed onto a grid beyond that grid's capacity to use it? | With the ascendancy of renewable or otherwise privately generated electricity, many electric companies allow electricity produced in excess of private use to be 'pushed' back onto the wider grid, even paying for that generated electricity in many cases. It makes sense to me that, most connected users being net-electricity-consumers, whatever electricity I push onto the grid is just used by someone else connected to the grid.
My question is, what happens once private generation exceeds grid usage? Where does 'unused' electricity go? What method or mechanism is used to shed excess energy in an electrical grid? | The grid is composed by several sections that can be opened, closed and rerouted to match supply and demand without putting too much current in the grid. If you put too much current elements of the grid would fail (transformers, breakers, even cables that could melt).
Depends on where the electricity is coming from you can disconnect that section not to overload the rest of the grid. The same can be done with demand (if an area is pulling too much current it could bring the rest of the grid down).
Grid management will make sure that excess current is disconnected from sections that can't support it. With power companies those loads are negotiated every morning and planned carefully during the day.
With home generation that production can also be predicted but contrary to the power plants, that current can't be disconnected easily, at least not without causing at least some local issues.
So there are two methods, either you get power plants to reduce production (which is not that a fast thing to do and after the bidding is done in the morning prices are already set) or you disconnect other big renewable generators (wind, and solar farms). Those can be disconnected from the grid and the energy is just lost to heat. | 22 | 101 |
What are good podcasts for learning more about existentialism? | I am still a beginner and I have loved reading about existentialism. I have read a little by Sartre, Camus, and Kierkegaard. I am looking for some podcasts to listen to for long drives and for when I bike that dig further, provide critique, or just quality analysis. | Philosophize this has very good intros to all philosophers including the existentialists
Partially examined life also looks at some specific works but is more a conversation than an educational lecture | 46 | 84 |
If Mt Everest's peak is the highest point above sea level and Mt Chimborazo's peak is the fartherest from the Earth's centre, which has the thinnest atmosphere? | Mount Chimborazo's peak is [2km farther away](https://oceanservice.noaa.gov/facts/highestpoint.html) from the Earth's core than Mount Everest, but Mount Everest's peak is the highest above sea level.
Which peak has the thinnest atmosphere? | There might be some slight variation due to global air circulation, but in general the air pressure should be determined by height above sea level. The same centrifugal force that pushes sea level somewhat further out from the core near Chimborazo will also affect the atmosphere.
So it should be everest. | 21 | 23 |
ELI5:Why is Stephen hawking so important? | Steven is important because he has challenged the status quo with plausible theories that have encouraged deeper debate and a greater understanding of our universe. He has turned a generation of young people on to science. He is also very important in what he has been able to accomplish while his mind has been trapped inside a non-functioning body. He has defied the odds, living decades longer than his diagnosis suggested and his contributions to science are staggering. He's also changed a lot of people's thinking about the value of handicapped people in society. | 104 | 70 |
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Was Schopenhauer the first philosopher to consider predation as a moral issue? | Jeff McMahan quotes Schopenhauer’s “[On the Sufferings of the World](https://ebooks.adelaide.edu.au/s/schopenhauer/arthur/pessimism/chapter1.html)” in his paper “[The Moral Problem of Predation](http://jeffersonmcmahan.com/wp-content/uploads/2012/11/The-Moral-Problem-of-Predation.pdf)”:
>This normally invisible carnage provided part of the basis for the philosophical pessimism of Schopenhauer, who suggested that “one simple test of the claim that the pleasure in the world outweighs the pain…is to compare the feelings of an animal that is devouring another with those of the animal being devoured.” | I'd wager you can find it as a moral issue going back thousands of years, judging by texts found in Indian philosophy and religion and the Hebrew Bible. You have Augustine and various other Church Fathers and medieval Scholastic philosophers debating the issue as well, though in a Christian context. | 10 | 58 |
What are some great philosophical books (fiction or nonfiction) that can be read in a day or two? (fiction examples: Candide, The Stranger, Siddhartha, etc) | On Liberty - Mill
The Prince - Machiavelli
Language and Myth - Cassirer
On the Social Contract - Rousseau
Oration on the Dignity of Man - Della Mirandola
The Ethics of Authenticity - Taylor
Pragmatism - Putnam
The Roots of Romanticism - Berlin
Rules for the Human Zoo - Sloterdijk
Reason and Rationality - Elster | 22 | 58 |
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How can one realistically get a PhD in a field completely different than their undergrad? | I was reading up on Sam Harris (love him or hate him his education is impressive) and he got his undergraduate degree in philosophy at Stanford then a PhD in Neuroscience at UCLA. How the hell can you do that? Is this out of the ordinary or is it pretty common?
Edit: As a side question, I'm going to graduate with a degree in cognitive science with a focus on neuro, philosophy and artificial intelligence. What jobs, activities, etc. should I be aiming for to get into a good PhD program for Neuroscience? | Ed Witten accomplished the same task, going from an undergraduate degree in Linguistics at Brandeis to a Physics PhD program at Princeton. His journey was quite special, as he bounced from career to career and even PhD program to PhD program before he finally decided on physics.
Obviously, it's much easier to take the courses necessary in college by majoring in it, but if you have the skills, test scores, recommendations, etc., you can find yourself in a different subject for graduate school. It just requires a lot of independent work. However, depending on the situation, it's easier to change disciplines if you're going from, let's say, a mathematics undergrad to an economics PhD. | 11 | 24 |
ELI5: When you search for something on Google, the resulting URL is filled with several pieces of information. What do each of these mean? | For example, when I do a Google image search for fruit, the resulting URL is https://www.google.com/search?q=fruit&safe=off&rlz=1C1TSNO_enUS566US566&source=lnms&tbm=isch&sa=X&ei=K0r4U5TfPNLmsASaq4LQAw&ved=0CAgQ_AUoAQ&biw=1600&bih=775. If we parse this by separating it at the ampersands, we get the following:
* search?q=fruit
* safe=off
* rlz=1C1TSNO_enUS566US566
* source=lnms
* tbm=isch
* sa=X
* ei=K0r4U5TfPNLmsASaq4LQAw
* ved=0CAgQ_AUoAQ
* biw=1600
* bih=775
What do each of these mean? | search?q=fruit: your search query
safe=off: safe search to exclude nsfw content etc.
rlz=1C1TSNO_enUS566US566: language and encoding information
source=lnms: origin of the search website, application, browser extension etc.
tbm=isch: type of search image, video, news, web etc.
sa=X: contains information about your search behavior. X means you clicked one of recommended searches.
ei=K0r4U5TfPNLmsASaq4LQAw: identification information for Google probably containing time stamp and some other things.
ved=0CAgQ_AUoAQ: contains information about which search link you clicked but its encoded.
biw=1600 and bih=775: your screen resolution
| 15 | 15 |
Is vaccination utilitarian? | One of the arguments for vaccination is that it saves more lives than damages. There are rare cases when vaccination can cause health issues. The reason to support vaccination anyway is that it saves significantly more lives. I find it similar to trolley problem. So does it make vaccination same to solution of the trolley problem by utilitarians? My second question is: what are examples of non-utilitarian reasoning that support vaccination? | >what are examples of non-utilitarian reasoning that support vaccination?
The reasoning you just gave appears sufficient. It's not like caring about lives is something uniquely utilitarian and that everyone who's ever cared about lives has been a utilitarian or anything like that.
In any case, this is not very much like the trolley problem. For one reason why, the doing-allowing distinction you're calling attention to is not strong enough to make the sort of ratio here a dilemma. Per the CDC, severe side effects have an incidence rate of one in a million. | 18 | 23 |
ELI5: What is the difference between civil twilight, astronomical twilight, and nautical twilight? | Sunset
**Civil twilight** - sun is setting, artificial light is not needed
Sun falls below horizon
**Nautical twilight** - sun has set, but it is possible to navigate by the shape of the horizon
Horizon is no longer visible
**Astronomical twilight** - Bright stars and planets become visible
Sky is fully dark, all stars can be observed
And then in reverse in the morning. | 66 | 44 |
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What is the difference between Anthropology and Sociology? | I've done a Google search, but in general they seem to say they are in fact quite similar, with the difference that Sociology prefers using statistical data, and Anthropology prefers fieldwork but that hardly seems to do much identify what seems to me very different methods, vocabulary, and key figures in the two fields.
Was wondering if someone could elaborate further on the difference, or at the very least, on a university curriculum basis? | Look in the etymology of the words in order to get a better view of their meanings Anthropology=science of man; sociology=science of society. Anthropology studies cultures, religions, small-scale interactions (in tribes or collectives or small groups), and mainly uses ethnography (field work), narrative studies and qualitative methods. Sociology, on the other hand, studies politics, economics, macro-relationships, social interactions, the influence of concepts such as power, ideology, class, etc., forms of organization, etc. Sociology tends to rely more on "classic" theory (linguistics, philosophy, politic economy, marxism, etc. | 38 | 39 |
ELI5:What are the colors in space? | I see pictures of outer space and I see all these vibrant colors. Can you explain this phenomena? Like I see a cluster of stars and like pink, green, purple, blue etc. Like what is that? How does that occur? I have no experience in astronomy if you couldn't already tell.
Here's what I mean:
https://en.wikipedia.org/wiki/File:LH_95.jpg
| Most of the color you see in pictures of distant galaxies and nebula is added in. The images are typically created using electromagnetic waves outside the visible spectrum of light, but this will vary picture to picture. If you posted an example picture of what you're talking about, you're more likely to get the exact explanation for that specific picture. | 27 | 56 |
ELI5: How does bacteria on food survive stomach acid to the point of making you ill? for example, Chicken can make you ill, not being cooked properly. | It was just a "shower question" that popped into my head. | Bacteria that need to reach your gut to survive have a number of adaptations to survive the stomach. Of particular note are a polysaccharide capsule and active proton pumps to regulate their internal pH. These are known as virulence factors, also they will "hide away" in food, and you can need very few to make you sick, so if you eat 100000000 and 1% survive that's plenty. | 1,640 | 3,331 |
ELI5: If radiation exposure causes cancer, why do they use it to treat cancer patients? Won't it just guarantee they will develop more cancer in the future? | Radiation exposure damages cells, including their DNA. Cells with damaged DNA can become cancerous because the damage can cause them to replicate uncontrollably, which is what a cancer is. But enough radiation exposure will kill a cell outright, including those which are already cancerous. So doctors administer radiotherapy in a carefully targeted way such that it only attacks the cancerous cells of a tumour, killing them but leaving the surrounding cells mostly undamaged. Because of the requirement for careful targeting, not all cancers are able to be treated with radiotherapy. | 42 | 20 |
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eli5: Why is english the world wide language of communication? | The era of the British Empire saw English being spread throughout Asia and Africa due to English colonies. They weren't, for the most part, going to learn the local languages, so they simply had the locals learn English.
Then, the American era began after WWII and they sort of reinforced that. | 12,682 | 10,522 |
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[General] In scifi galactic maps there are often 'unknown' regions and uncharted territories within their own galaxy. What reason(s) would a highly advanced/futuristic galaxy have uncharted spaces within their own galaxy | Bonus question what is ["wild space"](https://i.pinimg.com/originals/3f/57/8d/3f578d9f49542899dfd6f68a0adeeddf.jpg) ? | This is going to depend a lot on the particular setting, their means of FTL, their resource availability, the political divisions of the galaxy in question, and so on...
In settings with restrictive means of travel (Phase Gates, Hyperlanes, Slip-Routes etc) it may simply be a product of how those lines of travel disperse. You may have to go hundreds, or thousands of lightyears out of your way to get a path into a particular area.
Sometimes there are dead-zones created by political treaty, preventing travel to particular regions and limiting exploration of them.
Speed of travel is also an issue. Just because you can travel faster than light doesn't mean everything is instantly within reach. Even in Star Trek, it takes decades to cross the galaxy.
Regions can also be closed off due to stellar phenomenon interfering with travel. Warhamer's Warp Storms are probably the clearest example of this, closing off entire tracts of space for centuries, if not longer.
Then there's simple volume. Space is a really, really, REALLY big place. It takes time to explore, survey and reliably chart it. | 33 | 23 |
ELI5: Why aren't urinals shaped better to prevent splashing? | Somebody here has to be an engineer that can explain the physics of this to me. How has nobody invented a splash-free urinal yet?
It seems to me that if you made the urinal deeper- that is to say, made a tube shape that angled downward into the floor of the urinal- a man could safely urinate downward into the tube-shape (should he so choose and if he is in a state of sobriety with good aim) and not have all sorts of urine splash back on him.
It would be more sanitary for not splashing all over the floor too, wouldn't it?
TL;DR: Why aren't urinals shaped better to prevent splashing? | A couple factors go into the design of a toilet, most importantly for the business purchasing them is cost. If you purchased say, a funnel shaped toilet, you will also have a harder time cleaning it. If you are imagining a funnel that goes down into the ground, say, like an outhouse, there wouldn't be any splash back, but there would be more danger in someone slipping their foot into the hole, would be harder to clean, and would be more expensive if you needed to dig into existing foundation to put in this complicated toilet system.
There is hope, however! You can extremely minimize the amount of splash back by following these simple steps.
1. Get as close as you can!
2. Point downward, so the downward angle with bring urine down, not outward.
3. Do your business!
Where most people go wrong, is they tend to stay further back and just aim straight for the urinal. Urine isn't really a steady stream, and tends to break into many smaller drops. As they spread in random directions, liquid tends to bounce off and move to your shoes, which sucks. | 74 | 245 |
CMV: The lower amounts of attention for New York protests in reaction to the Eric Garner Grand Jury decision in comparison to the Ferguson ones in reaction to the Michael Brown GJ show how riots continue to be an effective protest tool. | So this is SUPER subjective, but I noticed how reddit is not really discussing the NYC protests on the same level as the Ferguson protests last week. Two days after the Darren Wilson No True Bill, it COVERED the front page, but here we are after similar protests from a similar case and there seems to be barely any mention.
Obviously, a lot of the reaction to the Ferguson protests was extremely negative, but if the purpose of protests is to bring attention to an issue, doesn’t this suggest that the violent ones that erupted in St. Louis were more effective than the peaceful ones last night?
I don't mean this post as a moral validation of violence, but merely a question of efficacy. I do not support the destruction of other people's property, whether it leads to awareness or not. | The Michael Brown case had more national attention both in terms of breadth and intensity from the very beginning. It is not unusual its fallout would too, especially considering the time that has since passed in each case (Garner's proceeding being further removed from the incident.) | 13 | 25 |
What facts or propositions are mostly agreed on by philosophers? | "Tenure is a good institution," "professors should be paid more," "students don't study as hard as they could," "the sky is blue," "the Earth is round," "strawberries grow on strawberry plants," "most cars run on gasoline," and billions of other things. | 45 | 17 |
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ELI5 the Google v. Oracle case | Specifically the whole debate over copywrite law regarding programming languages. | Oracle bought a company (Sun Microsystems) that had created the Java programming language. Now think of a programming language like a car. The concept of a vehicle with four wheels and some motor can't (currently) be copyrighted by any one company. A specific car has parts designed by a company (or companies) that are the property of the company (a motor by BMW, tires by Michelin, etc).
Now Oracle creates the 'Java' car, using a motor, wheels, seats, all designed by Oracle (really Sun). Google came along and said, let's make our own 'Android' car, but we want it to still be usable by people who know how to use a 'Java' car. So Google (supposedly) went and created an 'Android' car from the ground up, not trying to figure out how the 'Java' car was created, but taking the concepts of a motor, wheels, steering wheel, etc. The 'Android' car can still be used by a person who knows how to operate a 'Java' car, although the motor is meant to run on a different fuel, the wheels are smaller, and the seats are shaped differently.
Now, even though the 'Android' car is not the same as the 'Java' car under the hood, Oracle is claiming that the concept of a vehicle with four wheels, a steering wheel, and a motor is property of Oracle, and that the 'Android' car is just a "...cheap knockoff..." (actual quote) of the 'Java' car.
The real danger of this case is that Oracle will lock down the concept of a 'car' as property of a company. A company could make a three-wheeled motor cycle, for example, and another company could come along and say, "no, we invented the tricycle 100 years ago, and we demand you pay us money for licensing our 'three-wheeled vehicle design'". | 20 | 35 |
CMV: Modern Art Schools are Ugly and Dehumanizing | A common theme with a great majority of pre-modern artistic classics is that they showcase talent and dedication to the craft, often via the glorification of human beauty, intelligence and exceptionalism, amoung other innately admirable qualities. Greco-Roman statues glorified the perfection of the human physique, renaissance art glorified the realization of enlightenment and a higher state of mind, Victorian orchestra glorified mastery, grace and refinement, etc. All of the great classics to come from these groups were produced by immensely experienced and dedicated masters of the craft, who spent their entire lives honing their skills and expanding their tenure.
But now anything can be art, which means that everything IS art. The bar has been set so low that there's no demand for experience or talent. If anything can and is art, then anyone can produce art, and according to the modern schools of thought, it's of equal value to any other art. So why bother putting any effort into anything if it's just as good as a red strip down a white canvas some schmuck made in five minutes? Naturally, this attracts the kind of people who are averse to actual effort. The kind of people who think that "meaning" and metaphor are viable replacements for talent, aesthetics and other quantifiable metrics.
https://www.youtube.com/watch?v=OzsGmdmhDTI
https://www.youtube.com/watch?v=1un4Mots4pk
This is women screeching and stroking invisible penises. This is art.
I'm not going to link it, but "Interior Semiotics" is the process by which a woman opens canned food, rubs it onto herself, babbles like an insane person, and then freebleeds all over the place. This is art.
The simple fact of the matter is, when you have no standards, people will fail to meet them. Every time. When you don't hold art to the standard that it should glorify the most admirable qualities of humanity, it will default to showcasing humanity at it's most basic and depraved.
What do you think about all of this?
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ELI5: How did currency exchange rates form in the very beginning? | I was wondering how exchange rates formed in the beginning. As in, when the first two countries came together to exchange a monetary deal, how did they know how much of their money equated to the other countries money. | Countries often initially had their currencies locked to a precious metal (typically gold or silver). For example pound sterling (GBP) derives its name from when 20 shillings was literally a pound of sterling silver, under Anglo-saxon rule. These are pretty easily exchangeable because the international value of that coin is its metal content. | 31 | 40 |
Sexual Reproduction and Race? | When a mom or dad of two different races have sex (lets say white and black). Why is the product a "mixed" skin color, and not just black or white? | In order to have something like "black" or "white" only, it would mean that the genes for skin color, hair color, or other features you associate with "white" and "black" are specific to that race. They're not. Genes for skin color are more complicated, and they represent a whole range of possible tones and completions. Lets put it this way: genes aren't like on/off switches. Many are more like a volume knob, with many possible settings. Actually, more than one knob that all combine their settings to make up each person's unique genes. People from a specific part of the world might all have their "skin color gene knobs" turned towards the darker side or the lighter side. You mix the genes from someone with different settings and the kids will end up with something in between. There are also "dominant" genes. That is, genes that overpower other genes almost always. Brown eyes win over blue, usually, for example. | 13 | 23 |
Could two sheets of aluminum foil insulate a house? | Both sheets, not touching, in between the exterior walls: one to reflect heat back into the house and the other to reflect the cold outwardly? | Insulate to what extent?
Insulation generally takes advantage of the fact that air doesn't conduct heat very well. This is why fluffy things are insulating, they trap air within the fluff resulting in a barrier for heat transfer.
The trick here is trapping the air. Eventually heat will conduct through whatever barrier material you have and heat up the air. Hot air want to rise, and if you let it then convection starts. The hot air is replaced with cool, and the transfer proceeds all the quicker. Aluminum is somewhat reflective but it conducts heat well also. After all you don't wrap potatoes in foil to prevent them being cooked.
So if you just had a hollow wall with foil on each sides the foil would conduct heat through and the hollow space would allow a flow of air to start making a terrible insulation. | 14 | 55 |
ELI5: How do companies avoid tax using the Double Irish/Dutch Sandwich arrangement ? | Key things are transfer payments. You could create iamkimi Brands that owns all your product's names and trademarks and charges iamkimi Europe and iamkimi America to use those names and trademarks. Doing this smartly lets you recognize the profits wherever iamkimi Brands is located rather than where your sales are.
This gets your tax rate down to the level charged in a low corporate tax country (Ireland is the common example) at about 12.5%.
However, you can go much further. Doing this uses some unintended consequences of EU and EU member nation laws, with the goal of creating income that no one calls earned in their nation.
By setting up a Bermuda company that has an office in Ireland, Ireland doesn't consider it an Irish company, and Bermuda doesn't tax the income the company earned in Ireland. You can't just do that with the first firm, but by taking a series of steps (the original was to have the iamkimi Brands pay a royalty to a Dutch subsidiary (iamkimi Netherlands) and then pay another royalty to a second Bermuda/Irish company (iamkimi Brands2) you create income that neither country recognizes as corporate income.
And the US allows foreign subsidiaries to earn income indefinitely without tax so long as it's reinvested overseas, and you report to your owners the consolidated financial statements which include the income and assets from all your subsidiaries (the US firm iamkimi Holdings owns all the above firms so reports their income as it's own). | 744 | 1,975 |
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CMV: Legacy admissions to colleges and any other preferential treatment due to being associated with someone famous or someone that works their is unfair | I mean this is not a rant.
I feel that legacy admissions are a bit unfair sometimes. Since oftentimes (if not always) the legacy admissions policy gives preferential treatment to the poor 2.0 student that didn't give a shit in high school over a straight A high school valedictorian all because the 2.0 student is a son of a alumni to the institution and the A student isn't. This is especially unfair when the admissions to the college is very competitive.
It's said that 69% of students agree that legacy admissions is not fair, and 58% of legacy students say that legacy admissions are unfair.
I mean I don't see how being the song or daughter of a alumnus makes your more deserving of admittance to top institutions. Also, some people have a higher chance to get admitted all because they have a relative or friend that works at the university. This is also not fair since it's anti-meritocratic in a situation that's supposed to be meritocratic. | Legacy admissions are a significant fundraising tool for the school. Many alumni donate to the school knowing that there’s an increased chance that their kids will go there. Without legacy admissions, there would be less money for financial aid, ironically making it *harder* to admit the most deserving students.
If a few legacy admits each year fund a significant amount of financial aid, that seems like a good trade-off. | 932 | 3,604 |
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