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[DC] It took several years for Bruce to become as skilled as he is. How did the Robins get so skilled in far less time? | Dick was a gymnast, so he would have had an edge in acrobatics; this is understandable. Tim was already quite intelligent, while Jason knew the basics of combat from the streets.
But--apart from Damian, who was raised to be an assassin--how did the Robins get so skilled in far less time than Bruce? It took several years of intense, specialised training for Bruce to become Batman. However, for the Robins, a few months/years seem enough to turn them into polyglot, master martial-artist, detective badasses? | Batman had to seek out various masters and learn from experience. Not only that, sometimes they had very strict requirements to join them that were tedious and made the learning process take longer.
The Robins have access to the guy who went through all that and who prioritizes training them in practical ways, rather than the ceremonies of some of them. Students always have an edge on their masters, because they're taught everything the matter knows in an efficient way without having to go through the discovery themselves. Once they catch up they can continue with the progress at a much younger, fresher, and with a more open mind.
It took us thousands of years to get to the steam engine, but now that we have all this information to build upon, you can see people making them out of Lego. | 133 | 86 |
ELI5 What is the survival strategy of moss? It seems to be everywhere, especially when there is shortage of resources. | Well it depends are you talking about a moss or a lichens? Mosses tend to grow in moist environments where lichens (which are a combination between a moss and a fungus) tend to grow in dry places. Mosses will grow on the trees and ground and thats where they get their nutrients from, vs lichens that grow on rocks. Lichens breakdown the rocks that they grow on and that is where they get their nutrients. They literally eat rocks if that isn't a neich im not sure what is. | 36 | 42 |
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How do we know the rate at which atomic clocks lose time? | If they are the most accurate means of measuring time, what are they being compared to when we say they drift x seconds in y million years etc. | It's very simple, you compare them to each other. Because the error is random, calibrating a group of atomic clocks to the same time and seeing them drift apart gives you an indication of the individual error rate.
Of course, you don't know which one of them is right, most likely all of them will have lost time at some point, you'll only know how much on average they drift away from the right time. Which reminds me of an old joke: "A man with one watch always knows what time it is, a man with two watches is never quite sure." | 33 | 16 |
CMV: Capital Gains should not be its own separate tax but should instead be as a part of one's income | Pretty self-explanatory. We should not have a separate tax bracketing system for capital gains and that any income made off of capital gains should be considered part of one's income. Having separate rate and bracketing systems (especially today's) seems to only advantage those who are already rich and powerful. Today's capital gains tax rates are much lower than the tax rates for income. While I have heard it argued that we could make those rates and brackets the same, it still doesn't make sense that we have two separate rates of taxation that from a practical perceptive simply allows already rich and powerful to pay a lower effective tax rate than they would if their capital gains were considered as a part of their income and then taxed as income.
If there is something that I am missing about capital gains I would like to be informed on that. Also, if it was not clear, I am referring to the United States. | A couple points that i think have not been mentioned yet. First is that there may be a misunderstanding in your post regarding the brackets. The normal brackets tax income up to a point at one % and then all income above that bracket is taxed at the income of the next bracket. That is not how capital gains brackets work. The capital gains bracket that all of you capital gains are taxed at is tied to your income tax bracket. For example, if your ordinary income is $39,375 or below, there is no tax. Above that and up to $434,550 it's 15% and above that it's 20%. These are all in fact lower than the ordinary, but it's an important distinction to make that it's not it's own bracket.
The second point is how capital gains actually work. Capital gains accumulate over time but are generally reported at a singular event. If a stock appreciates from $1,000 to $2,000 over 10 years, you earned $100 per year on the stock, but report a gain of $1,000 in year 10. That's pretty tame, but if you apply it to something like a business that you started with $100,000, work on it for 9 years and are bought out for $1,000,000 you will suddenly have gains of $900,000 in a single year. Ignoring all other income, that $100,000 of earnings per year which in ordinary terms puts your annual tax bill in the 24% tax bracket. However if we used ordinary income brackets for the $900,000 gain you would be well within the 37% tax bracket on more than half of that income. There's time value of money and standard/itemized deductions and other income to factor in but in simplest terms it's also trying to mitigate the effects of these single year spikes. | 11 | 27 |
CMV: parents shoud always try to explain their decisions to their children. | I feel like parents make their decisions look way to arbitrary to their children even when they have legitimate reasons for their decisions.
Furthermore the fact that parents don't need to explain themselves sometimes allows them to make decisions that *don't* have good reasoning behind which can just hurt the child. This mentality from a young age can also hurt a childs critical thinking skills later on in their life because they are used to accepting decisions that have no good basis.
That's it. CMV.
Edit: Shoud should be should.
Edit: a lot of people are saying the same arguments so I will try to explain myself better: a. I'm only talking about instances that concern the child directly like when they want something the parent doesn't want to give them than it's not healthy for you is better than just No. Also I don't expect a parent to pursuade the child just to show the basic reasoning behind their decision. Like in every conversation the child is welcome to disagree or not accept the reasoning but at least the parent tried to cover the core of their reasoning. | Obviously, as a rule of thumb, parents should explain their decisions to their children. But you have to make room for exceptions.
- Timing, some actions need to happen on a quick timetable, you don't always have time to explain yourself in the moment.
- Maturity, some actions require a high level of maturity to understand - economics, legal issues, political issues - these sorts of things are not appropriate for 5 year olds a lot of the time.
- The decision itself is arbitrary, but it is important that parent and child be on the same page. You cannot explain non-existent reasoning. Sometimes you just have to make a choice and roll with it. "Why are we having fish tonight" "Mental Coin Flip". | 520 | 1,466 |
Psychology wasn't really an established field before the fin de siècle, so what did Nietzsche, Kant et al mean by "psychology" or "psychologist"? | Undergraduate psychology textbooks usually say that psychology started with Wilhelm Wundt in 1879, but if you look into the fine print, it’s because Wundt specifically started the first laboratory dedicated to the scientific study of psychology. And therein lies the rub: what started in 1879 was a separate discipline which saw itself as scientific; *the study of the mind* definitely did not start in 1879. After all, plenty of the concepts used by the scientific psychologists to explain their experiments have origins in, or predecessors in, the Enlightenment psychology of Descartes, Hume, Kant, etc. So someone investigating psychology in 1812 was investigating many of the same topics that a modern psychologist would; they just were using a philosopher’s tools - logic and argument, conscious experience and theorising - rather than putting statistics into SPSS and having different control groups, etc. | 137 | 135 |
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Why do rivers like the Nile and Amazon not form large canyons like the Colorado river did with the Grand Canyon? | Are they just newer than the Colorado river? Or is the ground underneath the rivers not as conducive to erosion? | Deep canyons tend to form where the land is in a state of slow, steady uplift where a river runs through it. So it's not so much that the water drills down into the earth, rather the earth is rising up around an existing river. | 68 | 179 |
ELI5: Why are tips based on how expensive a meal was? | Why are the tips we give in restaurants relative to how expensive/luxurious my meal was? How much harder is it to carry out a $30 steak from the kitchen compared to a $8 sandwich? I don't get it... Can't tips be a set rate? Or a per person rate? | At an expensive restaurant you are not just paying for the cost if the food. Part of why you are paying for is food service, ambiance etc. By tipping proportional to the cost of the meal waiters at expensive restaurants will be the ones with the most experience and will be the cream of the crop.
The other reason is that in fancy restaurants the tip has to be split more ways. The guy going around refilling waters, the people who bus in between courses, the people who bring out new fancy silverware depending on what you ordered, all if those people get some of the tip you leave. | 24 | 42 |
How does sugar contribute to heart disease? Is it the compound itself, or is it the empty calorie idea causing general undernutrition? | According to a 2014 study published in JAMA Internal Medicine, an increase of added sugar in the diet has a correlation with a a higher risk of dying from cardiovascular disease. The exact mechanism is unknown but is thought to have multiple pathways:
1. Sugar can overload the liver - the liver metabolizes sugar and converts carbohydrates to fat. Fatty liver disease is a factor in developing diabetes
2. Sugar raises blood pressure and inflammation
3. Sugar intake contributes to weight gain
All of the above are correlated with heart disease | 140 | 219 |
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ELI5: Why is air colder when it's moving fast? (fan, wind) | Air is an insulator and holds warmth you generate close to your skin.
Wind blows away that insulation layer and replaces it with cooler air that has not been warmed by the heat you emit.
Or something like that. | 18 | 18 |
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ELI5: How does 1 apartment key work for many things ? (Apartment building door, Underground Garage, My Basement lock, My Apartment..) | I might be dumb for asking, but unless its special type of keys, can someone else not take their key and have access to my things ? such as my basement lock or my apartment.
Key looks like a normal key but as again im no expert.
*Edit: Same key unlocks main apartment entrance, Underground Garage (Manually, if forgot FOB), Washroom for the building.. but also same key is my apartment entrance key, my basement lock key.. | Look at your key. See the teeth? Each one a number and each is a different height. The height is the value of that number.
If you've got a key that fits your personal door and a bunch of keys that fit a communal door, the communal door is only looking at the first few teeth (or last few). If you compare keys, the teeth at the front or back are going to be the same.
123456
vs
987656
The communal door is only asking for ....56 | 42 | 16 |
ELI5:What makes batteries chargeable and how are they charged in the first place | There are two types of regular (AA for example) batteries.
Non rechargeable batteries have two chemicals that send energy from one to another through a device. Once all the energy has moved from one end to the other or been used by the device, the battery is dead and must be disposed of.
Rechargeable batteries have two different chemicals. When plugged in to a battery-operated device, they work the same way as a non-rechargeable battery. But when plugged into a device with something else on it providing the energy, like your wall power outlet, the energy can be pushed backward and refill energy in the first chemical.
When you try to recharge a non-rechargeable battery, the energy isn't moved back, and instead turns into heat. This makes the chemicals really hot, until they explode out of the battery and make a really dangerous mess. That's why you shouldn't try to recharge non-rechargeable batteries. | 104 | 129 |
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Do we know how large dinosaur populations were? | When we’re shown concept imagery of dinosaurs, we often see that dino’s were plentiful. Is this accurate to the actual population sizes? | There are 2 easy ways to infer significant population sizes:
1. Fossilization is a very rare event. Therefore the rich fossil record requires a large potential number of dinosaurs to be fossilized
2. Species do not persist and evolve with small numbers. Disease, bad weather, natural disasters can and frequently do wreak havoc on populations. Small population sizes simply aren’t robust enough to survive in the long term | 181 | 339 |
ELI5: Why does paper become transparent when oil is spilled on it? | Due to the fact that the refractive index of the oil spilled is similar to that of the fibers of the paper, when paper absorbs the oil, more light is able to more readily pass through the paper and give the paper a translucent quality. | 20 | 16 |
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CMV: Video Games aren't a sport, and the term "eSport" is dishonest | Now, I'm not saying that video games are bad because they arn't a sport. I'm simply saying that they don't meet the textbook definition of a sport, nor the popular definition used by Sports fans such as myself. Some fans call them eSports, which I guess is accurate because the definiton was created specifically to accomadate video games. HOWEVER, I think the term is a little dishoenst because eSports is derived from the term "electronic sports", which does not apply to video games either, because they are not a sport.
For starters, if you google the definition of a sport, the first result you get is, "an activity involving physical exertion and skill in which an individual or team competes against another or others for entertainment." How does this definition apply to video games? It doesn't.
Additionaly, someone who plays a sport is an athlete, "a person who is proficient in sports and other forms of physical exercise." Is someone who is good at video games an athlete? I don't think so.
Video games are not an electric sport, because video games are not a sport. The electric part is not a disqualifiar. There are already sports that use electricity - for instance, foil fencing, a sport where both players are wearing conductive armor and are attached to an electirc wire, and score a point by pressing their sword into the oponents armor completing a circuit. Without electricity, you cannot play the sport.
Competetive LoL and Competitive CSGO are just that, competitions, and competitive gaming is a more honest name than eSport.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | >For starters, if you google the definition of a sport, the first result you get is, "an activity involving physical exertion and skill in which an individual or team competes against another or others for entertainment." How does this definition apply to video games?
Let's take LOL for an example. eSports LOL involves:
* The physical movement (**physical exertion**) of one arm and both hands, in precise ways that involve at least some required muscle memory.
* The ability to decide (**skill**) what do strategically in the game.
* A competition where you work together with **teammates** in **competition** with other teams.
* The broadcasting of the event live for others' **entertainment**.
So it seems like it literally satisfies the definition you're proposing. | 19 | 31 |
ELI5: How are scientists able to track the birthplace and movements of diseases like AIDs or the Black Death, even after people are long dead? | Through studying the remains of the dead, written records and genetic studies.
When it comes to remains, in case of ancient plagues this is usually restricted to the bones, usually found in mass graves indicating people had no time nor want to properly bury their dead. With more recent diseases, scientists can often study older preserved samples of blood or tissue, this way they found cases of people who had HIV/AIDS as far back as the 50s for example.
Then there are the written records - even if people didn't understand/recognize the disease, description of sympts are telling. We know for example from records of social workers in the 70s about an illness they then dubbed junkie flu/pneumonia which pretty well matches AIDS. With the black death, mentions of symptoms like thee emblematic buboes, among others in historical records is how historians can track where the plague appeared.
Finally, modern genetic studies allow modelling how the germ evolved and spread. Rates of mutation are thought to be constant, and so researchers could determine approximately when and where did HIV evolve from it's predecessor SIV.
All in all, historical research of diseases is a fascinating field that requires a multidisciplinary approach from a variety of experts pooling their knowledge together. | 27 | 43 |
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How do we know a single quark's mass if quarks don't exist as individual particles? | A proton's mass is 900-something MeV
A pion's mass is about 140.
And "Single" up and down quarks have masses of 2 and 4 MeV.
Wikipedia says that the rest of the energy comes from gluon interaction, at least in case of baryons. I can't seem to find the info whether mesons are too bound by gluons, but I assume it is so.
How did we figure how much mass is attributed to the quark itself and how much - to their binding energy? Did we just calculate the binding energy somehow and then substracted it from the total mass, or is it something more complicated?
Again, if a quark can't exist as a single particle, then what exactly is its "mass"?
Apologies if I'm misunderstanding anything. | For the light quarks, one can use chiral perturbation theory to relate the mass of the light hadrons to the mass of the light quarks. These two links give details and caveats of the procedures, as well as the most precise determinations. | 31 | 84 |
I believe that free will exists. CMV. | I could choose to eat a sandwich today or I could choose to eat a protein shake. As the sole agent operating my consciousness, I have ultimate veto power over all of my actions and decisions. My drives, desires, wants, needs may, to some extent, be formed by my environment, genetics, past experiences, all of which are determined by the laws of physics and the realities of the physical world; however, human consciousness, being a force so complex and powerful, is governed by an **agent**, which has the ultimate power to make decisions and is unpredictable.
I'm interested in hearing arguments against this idea. | Can you define what it means to make a choice? How is it different than what a computer does, or what a rock does when it's rolling down a hill?
What do you mean by human consciousness being governed by an agent? What is this agent, and how does it work? | 18 | 39 |
Are religious freedom and toleration good or bad for religious belief and practice? In both the domains of belief and practice, how does liberalism transform religion? | After reading The Social Construction of Reality by Berger and Luckman I'd say religious tolerance and its enforcement does weaken religious faith over time.
I'll provide a simplified argument. Any religion is usually legitimated within its own community and doesn't need to compete with alternative ideologies. It's ideology and way of life are enforced and reasoned with in the community and socialized into individuals. this means that those beliefs will remain relatively stable. The religion can of change over time, but it is in a sense the only choice the ability to change it radically won't exist.
Religious Freedom and Religious Tolerance assume a few different scenarios.
The first is that Religion A now has to compete with Religion B and reconcile the differences between the ideologies and legitimize itself. The first reaction will be to show how the other religion is false, even possibly using violence to regain its hegemonic place in society. The community of Religion A can still remain insular in a sense but it will now have to interact with people of differing beliefs, interactions will have to change and possibly the enforcement of their own beliefs be weakened to allow space for Religion B. (E.G. Religion A bans a certain food and punishes those who eat it. Religion B believes the same food is sacred and uses it for medicine. In the first scenario if anybody ate the food they would be punished. Now with a new group, Religion A can't punish Religion B without possible reprisal, they also now need to justify why the food is bad. Especially if others in Religion A community see the health benefits of the food for people in religion B.)
The enforcement of tolerance upon others weakens a religious communities ability to enact its beleifs that infringe upon others and also shows individuals in their community alternative belief structures that they can take on if their original community. A religion existing in a diverse community will be suspect to change much easier than before.
So ultimately I'd say its bad for the preservation of belief overtime, but good for enforcement of peace and competition between religions. We can use a real world example, if Catholics don't believe contraception is evil, they will use it, even if it is against their dogma. In a religiously tolerant society, the Catholic Church is limited in its avenues of reprisals. They can't enforce a new inquisition as done in the past for example. They can exclude them from the community and punish them in some way, but if those individuals simply leave the faith and go on to another one, then who cares really, the Catholic Church has no real power over their lives anymore unless they give it the power.
Religious Tolerance breaks down an religious community's capabilities to enforce its beliefs. Individual belief is what matters now. | 11 | 22 |
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ELI5: how does salt melt ice? | Salt will be absorbed by the surface of the ice causing it to become salt water. Salt water have a lower freezing point then fresh water. So the ice will melt even if it does not heat up. In fact it will cool down by this but because of the lower freezing point it will still be liquid. The salt in the water will then be absorbed by the new ice surface and the process continues until all the ice have become salt water or until the salt concentration becomes so low that it will not melt the ice any longer. | 19 | 21 |
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[MCU] Im building a criminal syndicate but New York has too many Superheroes protecting it. Where would be the best place in the world for me to build my criminal organization without constantly being harassed by Superheroes but also allowing it to grow and be well sustained? | it depends on what your syndicate needs to grow. The biggest contributing factor is how you make your money.
Do you need access to a port?
Do you need many skilled workers?
Do you need access to natural resources like iron, aluminum, steel, etc.
Do you needs lots or arable land for farming?
Do you need to rely on an outside power grid?
Do you mind competing with other syndicates? Because Honestly any country with high corruption will make it easier for a syndicate to grow, but you’ll have to compete with other syndicates in the area. | 54 | 63 |
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If I injure multiple ants in a given area, would they go back to the colony and warn the rest of the ants not to go there? | Actually, when ants are injured, their body sends a chemical signal that other ants pick up on and come to rescue the first ant. That is why if you kill one ant, one will come along soon, and if you kill that one, another will come looking for it. | 22 | 81 |
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What causes pictures to appear discoloured after being in direct sunlight for years at a time? | Just clearing out some old Xbox games and the logo on the side of them have turned blue after being in sunlight untouched for several years? | The effect is called photodegradation.
The part of a material responsible for it's color is called a chromophore. A chromophore is just a group of atoms in a molecule which are responsible for the molecule's 'color' - they have a specific absorption / reflection spectrum.
Sunlight can cause reactions in the molecule which change the structure of the chromophore so that it no longer has that specific absorption spectrum. Usually what happens is that the molecule no longer absorbs visible light, and now appears white. The more molecules are affected like this, the more bleached or white the paint will appear. | 15 | 19 |
[LOTR] What, if any, were the powers of the lesser rings compared to the One Ring? | The seven and nine ring's main power is to augment the natural abilities of the users- so generals become mightier, orators become better speakers, beautiful ones become more radiant. The the Nazgul became greater leaders and sorcerers and generals, the dwarven kings became immensely wealthy. It had the side effect of immortality and invisibility by turning you slowly into a wraith like shadow creature.
The three rings are different. Gandalf's Ring of Fire was said to "rekindle hearts in a world that grows chill". Elrond and Galadriel's rings granted them the power to magically protect their realms against Sauron and Morgoth's influence, and to do things like summon floods to wash away Nazgul. Vilya in Elrond's hands let him become the mightiest healer in the world, along with his elemental control. | 117 | 107 |
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If humans evolved as omnivores, why are we so susceptable to disease caused by eating raw meat? | We all know that cooking meat makes it safe to eat, but from an evolutionary standpoint, why were we able to kill a mammoth and eat it right then and there, whereas now we'd get sick and die? | In addition to these other good points, eating fresh raw meat usually isn't going to do anything bad to you, when it does do something bad to you, it probably wouldn't if you ate raw meat more frequently, and domesticated animals tend to live on factory farms where the bacteria in question can spread around unchecked. | 20 | 22 |
Concerning the lifespan of hunter-gatherers: | [This](http://www.anth.ucsb.edu/faculty/gurven/papers/pdrdraft04182006.pdf) suggests that they lived almost as long as modern people; conventional wisdom has them dying at 30. Is there something wrong with that study, or is the short-lived hunter gatherer just a myth? | There are two aspects to this:
(1) A lot of people died in infancy, childhood, early adulthood, or middle age. This drives down the *average* age.
(2) If you didn't die young, you might live to be old. There were still old people, it's just that a much higher percentage of people didn't live to be old. | 25 | 23 |
Why are some societies more progressive than others? | I live in an Asian society and looking at Western societies they are comparatively more progressive than Asian societies and I'm curious to know why this happens (or if anyone disagrees I'm happy to listen to that as well). Also I'm not trying to belittle Asians or Asian societies. If you can attach research, evidence or further reading it would be great.
Thanks | Check out Ronald Ingleharts modernisation theory. He talks about the connection between societies evolving beyond providing for safety/security to acquire what he calls postmaterialist values. That's things like civic responsibility, gender egalitarianism following periods of industrialisation and modernisation. He also has an interesting theory about intergenerational value shift through population replacement (younger people who don't have to worry about security care more about postmaterial values, slowly replacing the more material older generation). | 21 | 19 |
CMV: If my opinion as an economics major is not respected as much as my professors', then I should not believe a personal, uneducated opinion of Islam over someone with a PhD in Islamic studies. | Yes, this is a reference to the leader of ISIS, who has a PhD in Islamic studies.
I actually have no strong opinion on the matter. I've not read the Quran myself, and I believe that when it comes to religion, interpretation is key. However I can't shake this feeling that maybe moderate Muslims aren't peaceful because they have a better interpretation, but because they don't care about it as much.
After how I've been brought up to respect those in higher positions of education, I'm not sure why I'm expected to believe my friend (who has never read the Quran) that Islam is a peaceful religion, over someone with an Islamic studies PhD carrying out atrocious acts.
Edit: as a further question, if I'm not to believe this man with a PhD, what does that say for PhDs in fields like this? How could someone go so deep into the knowledge of a subject and get it so wrong?
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | A university professor generally doesn't have too many outside pressures or incentives to give a specific answer on an economic question. The head of ISIS however has every incentive in the world to give an answer that serves him and his organization.
It's a bit like asking Ben Carson about abortion safety. Yes, his credential as a medical doctor would seem to make him more trustworthy, but his massive incentives in relation to running for President counterbalance that, and you'd expect a very political answer from him. That's much moreso than you'd expect if he were semi-retired and teaching a couple classes at a med school, without the public spotlight on him. | 461 | 586 |
ELI5: How do big companies assess whether their TV ads were useful or not? | When we do other market research we will sprinkle in questions about whether they saw advertising, what they saw, what was their impression of it, etc.
Other times we do specifics research explicitly about the advertising. | 2,083 | 5,421 |
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ELI5: Why does GPU drivers update, if the GPU is the same? What will that hcange? | When you write software you use abstract terms. For a simplified example, you might say something like "Show this model on the screen". You do this through a graphics library like DirectX or OpenGL, or through some engine that converts it into a language like that.
In the long past, there was no graphics libraries, and there were no drivers from the manufacturers. The programmers would have to know exactly what commands to send to every card. Back then there were only a few models of popular video cards so this was something that could be done. But as there started to be more models of video cards it started to be too hard to do well. So maybe you need to load the shape of the model into the card in a very different way for one card than another.
Out of this, OpenGL and eventually Direct3d became a thing. The cards were designed to accept more general terms like "load this model". The thing is the cards had to have some way of accepting these commands, and sometimes new cards with new features would come out and need to accept new features. You couldn't rewrite DirectX or OpenGL every time you wanted to use one of these features, and you don't know on the card immediately what's the best way to do something.
So a driver is another translation layer. The graphics library sends an instruction to the driver. The driver decides what the best way to convert that instruction into commands to send to the card is. When you get an updated driver it means that they've either fixed a problem in translation, or made an optimization that translates that better to the card that you have. When new games come out, sometimes the game uses features in a graphics library in ways that are unexpected and can be optimized by changing how they are translated and given to the card, it's in the card manufacturer's best interest to make sure their cards perform well so they often work with developers to make sure they can get the best performance, sometimes necessitating a new driver version. | 11 | 20 |
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ELI5:How can Cities:Skylines with a 13 people development team do so much better than the multi-million dollar EA's Sim City (2013) | Several factors which may or may not be the problem.
1, budget. You don't know the actual budget and type of deals "maxis" has with EA. They are given a budget, and they are tasked to produce a video game.
2, All the talent left. Maxis effectively doesn't exist. Was bought off and basically destroyed. Given worse condition, were tasked to work on projects they dind't wanted to, or with people they didn't like. Using methods and financing that wasn't optimal, etc.... So the people who were the creative directors, writers, artists, AI programmers (the original talent left). And the subsequent filling of the position from another EA owned franchises or even outsorced might not been omptimal.
3, Inconsistency. EA promises something, then it tasks Maxis to do it. Regardless if it's possible. So they try their best. New sim city might have been marketed as big true succesor of sim city. But they might not have been what the actual devs were told prior.
4, Actual evil - EA is a big corporation with the history of doing cruel, hearthless and dumb moves in order to gain short time boost of profit. Such as buying of franchises, and subsequently selling their next game, solely on name. Letting the game being average shovelware with slightly above average budget, and talent. Taking no risks whatsoever letting the franchise go dull.
Dead space 3 is considered not a horror game. Which is how Dead space was marketed. And is almost a platform for microtransactions. Which is weird, considering its a single player game.
Sims 4 is shell of what it was. Most things are missing, the things that work, are dull.
Dungeon keeper is mobile ported pay to win crap.
Only Bioware somehow is still holding above waters. But even then, you see the influence of EA on their games. | 48 | 126 |
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what do you mean by degrees of freedom? | degrees of freedom refer to what “can” vary with respect to a given analysis. The best analogy I’ve ever heard about it - imagine you’re at a restaurant with 3 friends, and it’s time to pay the bill. The waitress comes back and asks “who has the Visa card?” and then hands it out. “Who has the Mastercard?”. Then “who has the discover card?”. But she doesn’t ask “who has the AmEx card?” - why? Because if the other three cards went to your three friends, the last one MUST be yours. That’s exactly like degrees of freedom - if you’re calculating a mean of a sample, every person in the analysis can be any score, but if you know the mean, the last person MUST be a specific score to make it true that the mean is what you observed (i.e., if you give me the first 19/20 scores on a variable and the mean of the variable, i can mathematically know with certainty what the 20th score on the variable was). That’s what’s meant by degrees of freedom | 91 | 39 |
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Why is Kant's Critique of Pure Reason more well known than the other two Critiques? | I'm referring to Critique of Practical Reason and Critique of Judgement. As a layman interested in philosophy, I rarely ever hear about the other two. | Both of those texts are very much talked about and studied by professional academic philosophers. One reason they aren’t spoken about as much is that the *Of Pure Reason* is hugely comprehensive. The issues discussed in *Of Judgement*, for example, are in depth expansions of issues touched on in Pure Reason. Additionally, Pure Reason is the most historically significant and influential.
That is not to say the others are not influential— just to say Pure Reason had a massive and lasting impact that overshadows the impact of the others— which are also seen as important texts for philosophy. | 14 | 18 |
CMV: Thank-you emails/letters after an interview are a waste of time | I've been on my fair share of interviews now and the common theme is that I should be sending a thank-you letter after an interview.
The way I see it is that I am grateful for the opportunity to interview and I'm sure to thank the people interviewing me before and after the interview. I don't see the point of a thank-you letter or why some Hiring Managers use it as a judge of someones character.
There are many people out there who may not be accustomed to the thank you letter standard, who may have been rejected simply for not sending one despite being qualified for the position they interviewed for.
If a candidate makes it to the point of getting to an onsite interview and shows up, they're obviously interested in the position. It shouldn't be a one way street where the candidate has to jump through several hoops while the company sits back and judges you at every turn.
To be fair, the thank you letter standard seems to be about 50/50. Some people say it has no bearing on the decision they make, while I've seen others claim they'll reject candidates for not sending one.
With that being said, I just completed another interview recently. CMV and maybe I'll send a thank you email.
| It might be helpful to think of it as a follow up letter rather than a thank you letter. Such a letter gives you an opportunity to address any issues that came up during the interview, ask questions, and most importantly, sell yourself one last time. Showing interest in and gratitude for the opportunity is an important part of selling yourself to employers. | 16 | 26 |
CMV: the US should have National Referendums |
So one of the biggest issues we have within our government is that the average person does not receive equal representation in government. There’s several examples of this, a lot of which tie into federalism (i.e. the senate, electoral college, etc.) but another giant issue is politicians just not actually being interested in supporting their constituents views.
It would be a step in the right direction to have national referendums to allow voters to directly have a choice and not pray to god their rep or the system itself doesn’t fail them. Direct democracy has some issues with it, not here to say it’s perfect, but so much of our government leads to unequal representation I think it’s one of the better solutions to fix that problem.
**I understand a good amount of people here are federalist but I would rather not make this conversation about that, yet I realize there’s a chance that is inevitable. The part of this I’m looking to be challenged on is more so the issue of said unequal representation and not “federal government good/bad”.** | Vast majority of decisions require a lot of insight and knowledge, and at least theoretically, we delegate this power to representatives to do their due diligence.
UK and Brexit is a pretty good example of uninformed public making a moronic decision based on ignorance. | 43 | 59 |
Eli5 What do flying insects do when it rains? | When thier wings get wet they are immobile so what do they do? | Knowing when it's going to rain is an important survival sense for a creature that's the size of a raindrop, so most smaller flying insects generally head for shelter when conditions become right for heavy rain.
A lot of them seek cover in the underside of leaves or the side of plants that are away from the wind. Some like bumblebees just park themselves and wait it out if they can't get to their hive in time.
And because bigger insects like dragonflies that eat the smaller flying ones don't have any prey to hunt, they seek shelter as well. | 4,666 | 4,928 |
ELI5: Why are eggs so ubiquitously useful in cooking? | It feels like eggs are in practically every recipe, but what makes them so useful and necessary for it? | Egg yolks are incredible emulsifiers; they help fat-based and water-based substances form finer blends. If you took a (pasteurized) raw egg yolk and added to it your salad dressing of oil and vinegar, you'd find that the the whole thing would form a creamy suspension that would stay together for a while.
Meanwhile the egg white are basically water and protein, which as /u/mb34i said can do some pretty impressive tricks. The bonus is that the fat in the yolks, and the water in the whites already have an emulsifier in the yolk; the egg is a complete kit to emulsify itself and anything else. An omelette, or scrambled eggs, is just such an emulsion, cooked. On its own, the white can also be whipped up into a tight froth and used to add air and volume to something that would otherwise not be raised, such as meringue, souffle, or mousse.
When you add all of those things and use them in different combinations, you have the reason for eggs popularity in cuisine. | 548 | 657 |
ELI5: How was the Civil Rights Movement in the 60's so successful at conveying a message and organizing it's members with the technology of that time? Why, with today's wealth of information at our fingertips, is the current movement for equality in the US such a mess? | It only seems all super organized because you are reading it in textbooks as a historical thing where they pick out the key points. It seems so clean and neat when it's just told as a story where rosa parks invented the idea of equality, then everyone had nonviolent sit ins, then martin luther king invented the idea of equality and died for our sins and then racism ended forever. All the rest gets edited out. | 43 | 21 |
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ELI5 why i can read a sentence several times but i do not know what tge sentence is saying. I recognize the words but its like they have no meaning. This happens when ive been studying for a while. | So you have 3 types of memory: sensory, short-term, and long-term. Most people are familiar with short-term (10-15 seconds, 5-9 items) and long-term (indefinite time, indefinite capacity) memory, but what you're experiencing is only sensory memory.
Information comes in through your sensory organs (eyes, ears, etc.) and is held in your sensory register, which is pretty much a temporary storage bin. If you pay attention to the information, it goes into short-term memory and (potentially) long-term memory, but if you don't pay attention to it, it gets dumped. The purpose of sensory memory is to hold little pieces of information long enough for you to receive the rest of it. You use sensory memory to remember the beginning of a word while you read or hear the rest of it. It's more efficient for your brain to store whole words than individual letters, so you don't save it until you have the whole thing.
So if you pay attention to information coming in, it can survive longer, but there's a lot of information that comes in through your senses that you don't pay attention to. Do you remember hearing that bird chirp outside? You heard it, but you didn't pay attention to it, so it made it to sensory memory and got dumped. What about when you look at your watch to see what time it is then have to look again 5 seconds later when someone asks you what time it is? You may have processed it enough to know that it's not time for you to leave, but you don't actually remember what time it is. When you're trying really hard to pay attention in class, but it feels like the words are going in one ear and out the other or when you read the same sentence over and over again but don't actually comprehend any of it? Sensory memory.
The issue is that you have limited attention. If you've been reading for a long time, if you're tired, or if what you're reading is really difficult, you can't process the information as well. Take a break, drink some cold water, or walk around for a bit. It may also help to read a couple sentences out loud. This makes you process what you're reading enough to say it out loud, which could jump-start the movement into short-term memory. | 668 | 952 |
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CMV: They say a relationship won’t solve any of your problems but literally every single person I know had a ‘glow up’ after finding a girlfriend and their lives all seem to be much better now. My view is that finding a significant other DOES, in fact, solve many of life’s problems. | I think I’ve said it all in the title, but yeah. If people shouldn’t “focus on getting a significant other, it won’t fix your life” then how come there are so many so-called ‘losers’ whose lives miraculously seem to get so much better once they have a significant other? I’ve seen people go from practically looking like bums all the time to suddenly dressing well, moving into new apartments, getting better jobs, and just overall becoming happier, more well-rounded, more interesting and positive people AFTER getting into a relationship. I think a lot of people would, in fact, benefit immensely from someone falling in love with them, caring for them and sharing some of life’s burdens with them. When you feel seen and someone is cheering you on and supporting you, your life DOES get better and I don’t know why there are so many people pretending like it won’t. | To modify your view here:
>If people shouldn’t “focus on getting a significant other, it won’t fix your life” then how come there are so many so-called ‘losers’ whose lives miraculously seem to get so much better once they have a significant other? I’ve seen people go from practically looking like bums all the time to suddenly dressing well, moving into new apartments, getting better jobs, and just overall becoming happier, more well-rounded, more interesting and positive people AFTER getting into a relationship
Typically, when people are telling someone to get their life together before getting into a relationship, it's because that person not only doesn't have a handle on things for themselves, they also aren't having success at finding relationships either - which makes sense, as many people don't want to enter into a relationship with an adult who doesn't have their own life together. So, for these folks, using relationships as a tool to get yourself together isn't feasible.
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And indeed, many people have their life well and truly together before they enter a relationship. For those folks, relationships add the happiness of being in a relationship on top of a life that is already well set up. They don't have to spend their time / energy "fixing up" a partner, or be "fixed up" themselves.
For other people, romantic relationships may be one of the few / only ways they get feedback from another person who is close to them, who gives them advice that they will listen to. In those cases, they may be more motivated / willing to make improvements in their life in order to be able to operate in / benefit from a partnership.
But of course, romantic relationships aren't the only reason or way to get your life together. It's something you can absolutely do on your own, and be motivated to do for your own personal benefit as an individual. Because in general, people who have their life together are better off, whether single or not, and are likely to make better partners.
Also, as a counter example to your observation, there seem to be plenty of folks who don't have their lives together, and also don't get their lives together in their relationships either ... | 56 | 161 |
ELI5: The top used Internet Browsers and how they're different. | As you may know, internet pages are written with HTML and various other languages. A nice analogy is to consider a web page as a museum. Let me explain.
The HTML is the architecture of the building itself. It's the building blocks of the page that tell you what things are and what they do. Using HTML, you give the browser data about what the page actually contains.
CSS is the paintings, or galleries, or whatever makes the museum appealing. CSS makes web pages look good. Without CSS, most if not all modern websites would look absolutely horrible. Just like a museum would just be a big empty building without its exhibits.
JavaScript is the museum curators. They let the guests experience the museum, and customize their experience. Similarly, all the interactive elements of websites (show/hide buttons, upvotes, etc) are JavaScript.
PHP is the workers of the museum. They keep everything going behind the scenes. PHP runs on the server and updates things like databases, just as a worker would change the museum (put in new exhibits, build expansions, etc).
Now, how does this relate to browsers? Well, a web page is just a file full of code. It's the browser's job to display this to you, the end user. In the early days of the internet, there wasn't much to display. Especially before CSS, most pages looked the same no matter how they were displayed and fairly bland. However, now, there is new technology; CSS3 has nice gradients, for example, and HTML5 has video and audio elements (you have probably seen Youtube's new HTML5 player at some point). The browsers have to update in order to work with these new forms of old technology, and they don't all do it the same. Most browsers don't even support all of it, and there's a website (I can't remember it now) which will tell you what browsers support what facets of HTML5 and CSS3.
TL;DR: They all display pages differently and support different web technology. | 14 | 16 |
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If I put 3 of the same item in the oven, the time to cook does not change. If I put 3 of the same item in the microwave, it takes considerably longer to cook all 3. Why? | A conventional oven maintains a more-or-less fixed temperature, which means that its energy output increases when there is more to heat.
A microwave oven maintains a more-or-less fixed energy output, which means that it takes longer to heat larger quantities of food.
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ELI5: My 12 year old brother wants to know why the debt between all the countries in the world cannot simply "cancel each other out." | The debts that most governments have are bonds not loans, governments have two ways of raising large amounts of money, taxes or bonds. This won't be very ELI5 as it's quite hard to do since governments operate very differently financially than normal people and it's a damn mess of mutual indebtedness.
A friend Bob wants to borrow $100 (a bond) off you he says he will pay you back in a month with an extra $10 (interest) as thanks. You trust him, Bob has a good reputation (AAA S&P rating) for paying off his personal debts with interest and on time (the bond matures), it's an easy and safe way to make an extra $10, you'd be pretty stupid to not lend Bob the money as it's 100% guaranteed he will pay you off with extra $10 or risks his good reputation next time he asks for money.
Lets say you are so confident that Bob will give you the money on time plus the extra $10 that you borrow $100 from another friend Fred, this way you have the cash in your pocket to spend now, you say you will pay Fred the $100 and an extra $5 when the times comes to pay him off for the trouble of lending the money. This isn't a bad deal you have $100 in your pocket still and even with the extra $5 you offer you to pay Fred you will still be $5 better off when Bob pays you back. Fred does the same thing with a friend of his called John, he borrows say $95 and will pay an extra $5 to John when the time comes to pay off the money.
Now here's the problem you are relying on that $100 + $10 from Bob to pay off Fred, if Bob doesn't pay up or can't pay the whole amount you won't be able to pay off Fred, and Fred won't be able to pay off John who might not be able to pay off someone else, it's a huge chain of mutual indebtedness that relies on Bob's excellent reputation for paying off his debts on time.
In the past Bob had a machine that let him print money if he couldn't pay you off, say Bob only had $90 at the end of the month, he would print off an extra $20 so he could pay you and protect his excellent reputation, you didn't mind this as you and all your friends do it and it guarantees you get all the money you were promised originally and you didn't do it very often, only as a last resort. Bob borrowed money from lots of people and most of the time he paid off the debts fine, sometimes printing money to pay the debts but only as a last resort.
Recently Bob and everyone else lost the ability to print money as a last resort, when the time comes to pay off debts he doesn't have a last resort any more, so he starts borrowing more and more money from friends to pay off other friends as he can't do it himself any more (for whatever reason, pay cut at work or something). He has a good reputation so people keep lending to him (multiple chains of debt), they are all relying on Bob to keep his word so they can can keep their word when it comes to paying debts.
Can you see the problem? It's a house of cards that will collapse if one person can't pay up since no one can print their own money any more, they are all relying on one debt to be paid so they can pay off another debt.
Bob comes clean and tells everyone he was lying all along about his income and that he can't afford to pay off debts any more, he was using the money he borrowed poorly, spending well beyond his income. His friends all say that if he doesn't find a way to pay his debts they won't lend him money again for a long time but because they all really need Bob to pay the debt so they can pay theirs they agree to help Bob get the money to pay off the debts and save his reputation. Now all the friends get together as a group and agree to borrow money from someone else (they will issue bonds to raise money) to pay off Bob so he can pay them off, before they do this they make Bob agree to a contract that limits his spending and he has to cut back his spending (Austerity measures), bob and his family don't really like this but have no real choice other than to lose their reputation.
Now if this all sounds like a real clusterfuck it's because it is, replace Bob with Greece in that and his friends as other European countries, the group they all belong to near the end is the European Central Bank which is the only place allowed to print money any more, individual countries can still issue bonds as can the bank itself. Essentially the Euro Central Bank ends up selling bonds to China and the money for those bonds will go to Greece to pay off its debts, but that money came with a lot of conditions which the Greek people don't like.
As for cancelling the debts, well anyone can buy bonds, governments, businesses, anyone even you and me. You might be able to cancel some mutual parts of the debts between countries but that won't work with multiple non-government parties involved. A country can write off the debts but that destroys their reputation as a trustworthy investment and no one will invest in them again, they'd have to rely solely on taxes for income.
That's pretty long and i don't know if it answered the question, i was more curious if i could write a simpler version of a current debt crisis. | 100 | 120 |
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Please tell me major things that old physics books have misinformed me on. | I recently started reading *Feynman's Lectures on Physics*, and a few years ago I read *Asimov's Guide to Science*. They're both absolutely classic science texts from which I can/have learned a ton, but I also know there are some caveats in learning out-of-date information. Some of them I can catch from my own knowledge (Feynman said that we don't know the intermediate between DNA and protein; Asimov said that we don't have solid evidence smoking causes cancer and that freon is a natural wonder with no detrimental effects), but I know very little physics and incorrect facts in these fields I am likely to miss.
Just curious, what are some big things that have changed, especially in physics (about which I know the least)?
Thanks! | The Feynman lectures took place in the early 1960s, and a lot of little things have been learned since then, but not too many big things.
The structure of protons and neutrons was just being discovered in this decade, which lead to quantum chromodynamics, the theory of quarks (partons according to Feynman) and their interactions. This makes up part of the *Standard Model,* which was formalised in the 1970s. We have since discovered that neutrinos have mass and oscillate between flavours.
The biggest discovery was perhaps in the 1990s, when we realized that the expansion of the universe is accelerating and that the cosmological constant/dark energy exists.
There are also lots of discoveries in condensed matter like high temperature superconductivity and fractional quantum hall states. Nanotechnology was basically the brainchild of Feynman and it's been moving along since then. | 23 | 50 |
Why is Mitochondrial Eve dated to 150-170,000 years go? | We know how fast genetic changes occur. If we look at all mitochondrial dna and count the number of genetic differences between all we have cataloged, we can follow backwards to they would all effectively be the same. Depending on fastest estimates and slowest estimates of genetic drift, it's roughly 150k-170k years ago.
And basically this means that we only know of one female at that point. We can see nobody else beyond her because we have no mitochondria that show genetic differences that come out older than that. Either they all died out, or they were bred out of the population. | 150 | 177 |
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ELI5: Why do we (and other chordates, for that matter) have our respiratory organs on our head instead of torso, which would make a shorter path to lungs? | Also, why have a centralized respiratory system with lungs and a single airway in the first place instead of having many breathing holes all over the body, like insects do? | Interesting question. Openings to the body create other issues, one being the maintenance of a sterile environment inside the body. All of them can be pathways for infection to enter the body. The respiratory "tree" is lined with cilia that move mucus up to the throat, then it is swallowed into the stomach, where stomach acid kill any bacteria.
Also, having a single airway allows us to use the air for speech generation (larynx), which has been vital in the development of human culture, but also important for almost all chordates. Having some dead space in the respiratory tree also allows for the air to be warmed as we inhale and for decreasing respiratory water losses due to evaporation. Consider also that we use the same upper airway system (well, the oropharynx anyway) for eating and drinking, which minimizes the number of openings to the outside. | 355 | 715 |
I beleive that quality of music completely depends on the taste of the listener and holds no real artistic value. CMV | Tu put it shortly I get tired when music snobs talks about how people are stupid for liking today's pop artists and I have never seen anyone provide real proof for what makes Beatles better than One Direction. All the great musicians in history have aspired for nothing more than to make someting "good". Without the lyrics it's just a melody and beat. It may sound great, but it can't put your view of something into another perspective like other art does. I also don't think you can argue that one melody is better than another. I like music and I like Beatles more than One Direction, but I'm uncertain of how much is culture/group pressure, how much is my individual taste and how much is actually real quality of music. To be honest I think that the musicians most worthy of appreciation are the makers of "modern" music (you know the one without real melody or beat). I may hate how it sounds but at least they try to push music forward as an artistic medium instead of just creating a catchy song. I really want my view changed on this because I want to really see what it is in a song that makes it good. | Music, like most art has as least three (probably more, but we'll do three for now) different ways of being "good".
Of course there's the visceral, physical impact, you listen/read/look/taste and enjoy. Let's call that the first way.
Beyond that, we can look at virtuosity. A lot of music, both in the performing and in the composing can be looked at as an exercise in skill, just like watching an Olympic gymnastic performance. When we hear, for instance, a classical singer hit every note perfectly in a complex piece with a huge range, there is a technical mastery there that objectively can be compared to crappy singing that needs autotune. This doesn't by itself determine the ultimate artistic value of a piece, but it contributes, and it's an element beyond taste. Of two musicians playing the same piece, one can be objectively better at it.
And we can extend this to composition as well. Great symphonies are often great technical feats in the same way that detailed sculptures are.
And beyond that, we can value innovation. If a song feels nice to sing along to and is well played but still sounds pretty much like every other pop song, there is a distinct value it is lacking. As individuals we can decide how important that value is to us, but we can't deny its existence. Frank Zappa created music that didn't sound like the music before it, that broke ground.
Even if you happen to prefer One Direction over Zappa on that first, visceral level, you would have to admit that it was a better work on those two other levels. You'd still be free not to enjoy him, or find other reasons to think the work was bad, but it has objective value as innovation and performing and compositional virtuosity. | 38 | 47 |
ELI5: How do we know that the sun was formed around 5 billion years ago? | There are various methods, such as using computer models of stellar life cycles, but the most tangible way is simply that we know that other things that probably formed around the same time as the Sun were formed around 5 billion years ago.
It's likely that the entire solar system (the Sun and the planets) formed at roughly the same time, so to approximate the age of the Sun, we can take a look at the age of objects in our solar system. The oldest meteorites we've found are approximately 4.6 billion years old, according to radiometric dating; round that up to 5 billion and there you have it. | 203 | 521 |
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eli5 Why do diabetics sometimes have to have limbs, particularly their legs, amputated? | Diabetes is a disease in people where the body does not produce insulin (type 1 diabetes) or does not use glucose properly (type 2 diabetes). In both instances, there can be a high level of glucose, or sugar, in the blood.
Uncontrolled high blood sugar damages nerves and interferes with their ability to send signals, leading to diabetic neuropathy (tingling and loss of feeling$. High blood sugar also weakens the walls of the small blood vessels (capillaries) that supply the nerves with oxygen and nutrients.
The combination of poor circulation and lack of feeling in the limbs leaves those areas prone to infection or cell death (from not receiving oxygen or nutrients). Infection can go unnoticed for quite some time, past the point of recovery and would require amputation so the infection does not spread. It is difficult/impossible to get an appropriate amount of antibiotic/antifungal medication to an area with poor circulation. | 41 | 18 |
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ELI5: Why do we age? | I'm wondering, why do all creatures eventually age and die. If our bodies are able to recreate cells, and repair skin, etc. Then what causes us to age, and eventually die? And why do different animals have drastically different lifetimes? | Our bodies are able to recreate cells and repair skin and stuff like that but there are limits. You know how if you have an accident, maybe you accidentally cut yourself with a knife while preparing vegetables, the wound will close up without much issue so long as you protect it and make sure you don't get an infection but you'll always have a scar showing where the cut used to be. Likewise, your body will produce new cells to replace the old ones as you age but the replacements won't be quite as good. The older you get, the slower and less accurate your replacement system gets until one or more of your organs can't do its job any more and you die.
The reason we die is essentially tied to evolution. The strength of evolving creatures is the ability to adapt to environments. When the environment changes, creatures that can't adapt to the new environment die out. Being able to age perfectly doesn't help you in this situation. What you need is a population that can change as the environment changes. Death allows you to make room for new and varied offspring, some of which will be suited to however the environment changes next.
If it helps, you could kind of think of this from the perspective of running a telephone company with a fixed budget. You can only afford to employ so many workers but technology keeps changing. When you go from manual switchboards to automatic, do you keep the old operators or do you hire people who know how to program the computers?
Different animals have different lifetimes for various reasons. Some of them are very short-lived because their environment allows only a small window for reproduction or because it allows them to adapt to new environments very quickly. Some of them are long-lived because they are capable of surviving in a wide range of environments or because their chosen environment doesn't change much. Other aspects such as reproductive capabilities, intelligence or dependence may also play a part.
Humans, for instance, have young which are vulnerable for rather a long time. The advantage of this is that we have time to develop remarkable intelligence in the long run. In the short term though, it means that the parents have to live for long enough to protect their offspring until it can protect itself. In contrast, there are a number of animal species where the adults die shortly after reproducing and the young are either protected by numbers or born at a stage where they can function as adults nearly straight away. | 20 | 21 |
I believe it's naive to think that climate change can be prevented, CMV. | As an Earth Scientist working with and amongst climate researchers, I agree that anthropogenic (man-made) climate change has a significant -- yet unclear and complicated -- impact on the earth's climate, both now and in the future. But I also think climate change is ultimately something we can't prevent and need to learn to accept and live with.
Why? There is a wealth of geological data which says that the climate change has been common throughout earths history (e.g. as demonstrated by sequence stratigraphy, biostratigraphy, lithospheric flexure calculations, etc). There's also compelling evidence showing that climate change can happen rapidly even without human influence (e.g. volcanic eruptions, meteorite impacts, solar events, threshold triggering of dynamic processes, etc). Furthermore, rapid climate change has already been observed or implied in human history (e.g. little ice age, the year without summer, out-of-africa reconstructions including mt toba eruption, etc).
Due to the complex influence of humanity on the climate, and the near certainty of both long term and rapid climate change happening anyway, I believe it's naive and counterproductive to attempt drastic measures to prevent climate change.
Please attempt to change my view, and convince me that "preventing climate change" is more than a mantra repeated by those with vested interests. Perhaps I have missed something, or not yet thought about it in the right way. | Even if we cannot prevent climate change, is it not in our best interests to mitigate the effects? Humans are best suited for environments without extreme weather conditions, and seeing that man made climate change is producing these undesirable conditions, by all reasoning we should cease these actions. Even if we cannot prevent naturally occurring climate spikes, anthropogenic change exaggerates an already bad situation, therefore it is in humanity's best interest to limit C02 emissions so we can weather the naturally occurring change without having to also deal with the man-made effects as well. | 18 | 57 |
ELI5: Why doesn't the 4th Amendment protect people from mass surveillance? | > The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
There are a few key words here that were left open to interpretation. Notably things like "unreasonable" and "probable". If the courts decide that something is not "unreasonable", then it's fair game. Likewise, if they decide a situation gives "probable" cause, then it's fair game. Nothing on the Bill of Rights or the Constitution really elaborates on what those words actually mean, so courts have to decide as best they can what fits the intent of that amendment, and others.
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What the hell happened to the academic job market in the past ten years? | I've heard all of these mythical tales about the bygone era of 2001-2007, when new graduates, PhDs in hand, would get some postdoc fellowship straight out the gate, and go on to some tenure track position thereafter.
Nowadays, I see people graduating with PhDs from top ten universities with mile-long resumes who send out more than a hundred applications and still can't find a job. I've been told that the financial crash in 2008 had something to do with it, but what exactly? What changed in university departments that led to the job market being so awful? Why does it continue to remain awful? Will it continue to remain awful? Or do you reject the premise of my question, and conclude that the academic job market is just fine?
Mainly, I've heard about this in the humanities, since that's roughly where my field is. I'm not sure how it is in the natural or social sciences. | (This is purely anecdotal; someone else can research the data and see whether these guesses are right.)
I would hypothesise two effects in the United States:
* The Great Recession leads to an increase in unemployment in many industries. Fewer jobs available to college graduates means more people go to grad school instead. More people in grad school means, a few years later, more people with PhDs chasing the same number of positions.
* The Great Recession, along with the ascendance of Tea Party or other anti-tax politicians, leads to a drop in state and federal revenues. A drop in state revenues leads to less funding for public universities; a drop in federal revenues leads to less grant funding. Less funding for universities means fewer new positions get created, and some retiring scholars are not replaced. So there are fewer positions available for the PhDs to chase. | 89 | 99 |
I believe children born with severe illnesses that have no cure should be euthanized. CMV. | Hear me out.
If you speak with people that have been clinically dead, or even if you have been under anesthesia or even just a deep sleep, you don't realize you were under until you're out of it. It happens suddenly, it's painless and most people recall to be at peace. Even if you look at dead bodies, they look very peaceful.
In some cultures, death is a gift and is the greatest gift there is. Even here we have a saying "he/she is in a better place now". So why do we let these kids live on and why do we test them and try and try even though we know the end result. I'm not talking about down syndrome or any manageable disorders, I'm talking about those that are painful and greatly reduce the life expectancy of the kids.
**I should rephrase the "should" in the title. What I mean is that euthanasia should be be allowed, sometimes encouraged at the discretion of the parents and health care professionals. I do not mean mandatory euthanasia.**
EDIT: Some clarification on my view. I'm also talking about severe birth defects, if you Google that you'll understand what I mean. Although reconstructive surgery has made some impressive breakthroughs, that only deals with a minor percentage of birth defects. What about the cost? The average parents can't afford to pay to keep these kids alive, especially knowing that it might not end well.
EDIT 2: There are some really good arguments here mainly the fact that a lot of the diseases that can be cured were at some point incurable. Also we can't decide who deserves to live or die and the child or loved ones might actually cherish every moment the child is alive. However research is leaning towards being able to detect the defects early in the pregnancy to avoid this situation entirely. My view still stands but I do understand the other arguments.
Great discussion guys! Just when I slowly start to think about changing my view, someone brings up a great argument that re-enforces it. | The problem with your position is that it requires someone other than the person with the severe illness to assess whether their life is on balance worth living. An individual can assess the entirety of their experience and determine whether the good outweighs the bad or vice versa, and they can make an informed decision on whether life is worth living. The problem arises when you say that *others* should be given the power to decide to euthanize those with birth defects -- are those others in a position to assess the whole of the child's internal life? What if the child, despite being in pain or having some disability, also greatly enjoys living such that despite their pain they very much want to remain alive?
I have known people who had severe chronic pain but still found great joy in life. How would we know that the child does not in fact derive pleasure on balance from living? We can't ask the child unless they are old enough to speak and understand such weighty questions. And if we did ask the child and they wanted to die, that would not be euthanasia, it would be humane assisted suicide.
Surely there are cases where it would be merciful to euthanize children whose lives are constant agony, but how do we tell these children from the ones who enjoy life despite their disabilities? Both types of child may cry, both may *seem* unhappy, but we cannot be anything close to certain regarding their subjective, internal lives.
I think the situation is similar to the reason we require such a high standard of evidence for capital punishment. Surely some guilty people go free because of it, but we find that it is better to let a few guilty people go free than to execute someone who is innocent. In the case you are presenting, isn't it better to err on the side of caution to avoid killing children who would very much want to go on living? | 168 | 279 |
CMV: The one-year expiration of an eye exam for prescription eyewear is a scam | I've worn glasses or contacts for twenty-six years. When I was young, my prescription changed every 2-3 years, but it has not changed at all in the last 12 years. But still, every time I run out of contact lenses, if it's been over a year since the last exam, I have to go get my eyes checked to confirm that I still have the same prescription. I get that you need a professional to determine what your prescription is initially, and I get that you might want to check in periodically to make sure it hasn't changed. What I don't understand is why contact lenses need to be controlled like prescription painkillers. Why can't my eye doctor (who has examined me for years with the same results every time) specify that my prescription expires in 3 years instead of one? Or why can't I just buy contacts over the counter, like you can in lots of other countries, and get eye exams at whatever periodicity makes sense to me? The whole thing just seems like a racket to keep people paying for eye exams they don't need.
> *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!* | The issue with contacts, unlike glasses, is that you are putting them in your eyes regularly. This creates a whole list of potential problems that if left unchecked may lead to permanent blindness. Many times these issues are only caught when someone goes in for an exam since the initial symptoms are minor enough that many people brush them off and don't seek help until they have trouble seeing and now it's too late. Setting limits on how many contacts you can buy without a new prescription helps to get people into check ups where issues can be discovered before they are permanent and expensive for both you and the state. | 10 | 24 |
ELI5: Why we need sleep | Sleep enables the body to release important hormones, repair cells and of course recharge the brian.
Our body is basically like a vehicle that needs to be repaired and tuned up every night. Of course you could drive without doing that but it'll only get worse and worse until it completely stops working. | 18 | 41 |
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ELI5: Why do some people look unattractive in photos, but look attractive when in person? | In converting a 3d image like a person into a 2d image like a photo, some features are lost. Part of modeling is knowing which features to accentuate in order to look right on camera. When taking a photo one might stick their chin toward the camera, it looks weird in person but it prevents the camera from making you look like you have a poorly defined chin due to the flat image. | 4,494 | 4,548 |
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CMV: The US House of Representatives should grow much larger | A key part of the job of any representative is to be able to represent their constituents in front of the legislature. With the current number of representatives capped at 435, congresspeople have - on average - 733k people living in their district. For a few points of comparison, here are other Western democracies and their population per member of parliament:
Country | Count of Seats in Lower House | Population of Country (in millions) | Population per Rep
---|---|---|---
United Kingdom | 650 | 64.1 | 98k
Canada | 338 | 35.16 | 104k
Germany | 630 | 80.62 | 127k
France | 577 | 66.03 | 114k
United States | 435 | 318.9 | 733k
While many other democracies see fit to have approximately 1 representative per 100k people, the US is more than 7 times smaller than that.
A key part of a democratic republic is that the people send someone to the capitol in order to represent their interests. For a congressperson with over 700k constituents, they aren't going to have the time to meet with any but their largest employers, donors, and most politically connected. Much of the day-to-day work is passed off to aides. Redistricting plays a much larger part of the balance of power, and election campaigns are significantly more expensive.
If a congressperson only has < 200k people in his district, then almost every mid-sized town would have at least one or two representatives. Even suburbs of major cities would have their own representatives.
Aside from feasibility concerns (considering Congress would have to vote to dilute their own power), what would be the downsides of a 1500+ person Congress?
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Perhaps the best point to look at is that the US is a federal system where many of the more specific details of constituents are, or should be, dealt with on the state and local level. For comparison, the Maryland legislature has 140 reps in the lower house for 6 million people, which comes out to about 50k people per rep. Very adequately represented. | 15 | 43 |
Biologists: Do you feel a DNA-based taxonomy is better than a morphology-based one? Should the new DNA-based model replace the older morphology-based model (with 250 years of data) or simply augment it? | [This paper](http://xyala.cap.ed.ac.uk/teaching/retired_teaching/ecology4/Tautz_et_al.pdf) proposes a DNA-based model as the primary means of classifying organisms while still retaining morphological data. In "Box 3. Introducing a DNA taxonomy scheme", they describe what they believe will be needed to achieve this. A DNA-based model makes sense to me, but with 250 years of inertia behind the current model, would switching models be impractical or meet with resistance from scientists that may be more comfortable with the current model?
Has anything happened since that opinion paper was published in 2003? | Essentially, molecular classification is the best way to identify and relate species. Molecular data is not succeptable to errors of inference, wheras morphological data is, examples of pseudo-species and convergent evolution highlight this.
If you want to know more about relating species at a molecular level look into phylogenetics and particualrly Carl Woese's paper in which he redifined life as a 3 pronged tree.
You might also want to look into clades such as Afrotheria which contain species that seem strange to be grouped together as it may seem bizzarre that they are closely related, but the molecular evidence of their close relationships do not lie! | 17 | 39 |
ELI5: What is a game engine? | Let's say you're making the game Super Mario Brothers.
You start writing the code for level 1-1. You write code to add some blocks where they go, put a goomba in, put the pipes, etc. Then you write code to keep track of where Mario is, how he jumps, and what to draw on the screen depending on where he is. Awesome, level 1-1 is working perfectly.
Now it's time for level 1-2. Hmm...well this level also has blocks, and goombas, and pipes. So I'll just copy the code from level 1-1 and paste it here. And Mario still moves around and jumps, so I'll copy that code too. Now level 1-2 is working. We're making great progress. Sure, 90% of the code here is the same as from level 1-1, but it works so we won't worry about it.
Now we've done this for a lot of levels. We have worlds 1 through 4 done! But uh oh, we just discovered a bug in the code that makes mario move around. And we've copied this code into all 16 levels we've coded. Ok, so we'll just go through all of them and fix the bug. That's kind of tedious, but it works.
Then someone else comes along with a brilliant idea. What if instead of writing separate code for all our levels, we made up a way to put how a level looks into a text file. Like maybe one line would be "block 23 9" which means that on the 23rd column of our level, there's a block 9 squares above the ground. Now we can save all our levels in files, and then just write code once that will load the file for a level, then draw that level, control how Mario moves around in it and jumps, and all of that. We don't have to copy and paste it for each level anymore, we only have to fix bugs we find in one place.
What we've just created is the game engine for Super Mario Brothers. | 32 | 33 |
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ELI5: How do scientists predict, down to the exact degree, what the temperature will be for the next week? | They will generally use high-resolution, regional weather models. These are essentially computer programs that solve a set of equations that aim to represent the physics of the atmosphere and ocean. These equations are extremely complicated so these models are also very complicated, which is why meterological agencies generally own very powerful supercomputers to solve them.
There are two main reasons why there is so much uncertainty in weather forecasts. Firstly, the equations being solved are chaotic which means they are extremely sensitive to initial conditions. Whilst weather stations allow us to gather data about the weather *now* so we can plug it into the models to find out the weather in a few days, we only have a limited number of weather stations, which means we have to 'guess' some of the initial conditions. These initial guesses introduce more and more error as the model steps forward in time. Part of the way we get around this is by running a set (an 'ensemble') of models with slightly varying initial conditions to represent our uncertainty, and then look at how widely or closely the outputs agree with one another.
Secondly, whilst we understand the fundamental physics of the environment, these equations have no exact solutions which means that any numerical solution we obtain through a computer is going to be an approximation. The complexity of the physics a computer can solve as well as the spatial (how small a grid cell a computer can model, the smaller the grid cell the better the results) and temporal (how small the time-step is, the smaller the better) resolutions are limited by how powerful your computer is. | 11 | 17 |
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Is a doctorate of philosophy (PhD) related to philosophy in any manner? | Is PhD in any field about understanding the philosophy of a given topic? Like having a knowledge of the depth of a philosopher but in their respective field
Or is it just a name which stuck as philosophy means love of wisdom in Latin (according to Wikipedia) | philosophy used to (still does) encompass all disciplines of knowledge, like natural philosophy (study of physics). then we slowly branched out and created all these sub disciplines where philosophy would be the back bone.
so you could really say a PhD stands for a “doctorate of knowledge” you are an expert in a discipline that came from philosophy | 187 | 113 |
ELI5: How do power plants know how much electricity to generate? | Are power plants constantly overproducing electricity to be safe? What happens to the excess energy? What happens if there isn't enough energy to supply the grid? | There are many different kinds of power plants with different performance characteristics, and they're used in combination to ensure that the supply of electricity matches the demand as demand changes throughout the day.
In one group, you have the "base load" power plants. These are typically things like large coal and nuclear plants that produce electricity very cheaply, but need to run at 100% production all the time, and take a long time to turn on or off (on the order of several hours up to several days). These just run at 100% production all the time.
Next you have the "peaking" power plants. These are typically natural gas plants that produce electricity more expensively, but can be turned on and off quite quickly (sometimes within a few minutes). These are used to handle the times of highest demand, and only run for a few hours a day, if that.
Finally, you have "load following" power plants. These are plants that can modulate their output to ensure that the right amount of power is available when it's needed. There are a lot of different kinds of plants that can do this, though sometimes they have to have some modifications from the standard design to allow load following operation. These are used to handle the fluctuations in demand outside of peak hours, when they'll be running at full output and the peaking plants will be used to produce the extra supply necessary.
The grid is constantly monitoring the amount of load currently connected and feeding that information back to the power producers in order to ensure the correct amount of supply is available. Small fluctuations are handled by the grid itself: the miles and miles of power lines and other infrastructure act as a giant capacitor and can either store up excess energy when there's an oversupply or discharge it if there's an undersupply. The grid changes frequency slightly when that happens, and the grid operator tries to ensure that those frequency changes balance out so that the average frequency of the power system is consistent over the long term.
If there's so much load that there isn't enough power generation supply available to satisfy it, the grid will disconnect some customers to bring things under control. The details depend on the specific legal framework and operational systems in place. In some places, large power consumers like factories or office buildings can agree to be the first ones disconnected in exchange for getting a deal on their power bills. In other places, the grid operator will impose rolling blackouts via some specific schedule. There are some other ways to do it as well. | 10 | 15 |
ELI5: Why do we still use concrete and asphalt for our roadways? Why have we not found a better material that is less prone to potholes and always feels smooth to drive on? | You could design and build a surface that is "better" in being more elastic and less prone to cracking.
However, asphalt and concrete are mostly just rocks with some binders in them. Quite literally nothing else you try to use will be as cheap, readily available, easily brought to site, and easily fixed.
There's more considerations in play than just making the best feeling road. | 1,275 | 676 |
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Humans have 'friendly' bacteria that live in their gut. There are four dominant phyla present. How did they get there? If it was based on diet, surely people from different parts of the world would have different bacteria in their gut? | Gut bacteria are introduced through the mother to the baby during birth. Babies usually come out headfirst and mouth open. They are inoculated then. Later other bacteria can be introduced when the baby ingests them as food or by putting things in their mouths. | 43 | 141 |
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ELI5: Is there any difference from your livers perspective to drink slower, but still at capacity (i.e. 1 standard drink per hour) or is it the same as drinking a lot of drinks at the same time and the liver getting 'backed up'? Is one of them better for your liver? Is there a 'waiting room' per se? | Imagine you had 8 clients booked in at work, and each job would take one hour to complete. If each client arrives on the hour, your day will go smoothly.
However, if all 8 clients arrive first thing in the morning, your day will be very stressful as they are all sitting around waiting.
Similar for your liver in this context | 263 | 301 |
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ELI5: Why don't NFL teams train wide receivers to play cornerbacks? | For example the average cornerback is shorter and doesn't have good catching abilities. I would imagine having a receiver defend a receiver would be the best in 1v1 man situations. | There are different skill sets. Running backwards, zone defense, watching the qb, tackling, etc.
A receiver would be better at the catching the ball part (which is why sometimes they go stand in the end zone when someone is trying a hail mary, but not as good at the other parts.
Football positions, especially in the NFL are a lot more specialized than when we were playing in the street and everyone was a receiver and a cornerback. | 19 | 28 |
CMV: All labels to identify activists or certain groups of people in general (ex.Feminist, ANTIFA, Alt-Right, Liberal) are hurting society more than they are helping. | I strongly believe terms used to identify large groups of people who support a certain cause used to show simply where you stood in the discussion, in recent years, however, they have been used to identify a person.
Social Media has perpetuated this judge a book by its cover mindset, allowing these terms to make 2-dimensional caricatures out of regular people that, at times, have opinions that don’t completely align with the group they are supporting, but they are lumped in with the group as a whole anyway. These labels have become stereotypes, something we’re supposed to avoid as a civilized society, so that the country doesn’t divide into tribal mentality. When someone doesn’t like an opinion of another person, instead of discussing it, they label one another, “Well you’re just a filthy liberal/alt-right because of that opinion,” this is incredibly detrimental to society.
For us to unify the US again we need to relinquish these labels all together, or at least give them less power, so that we can go back to discussing issues civilly. These stereotypes/labels give the opposite effect of turning people towards their causes, because the public’s view of them is easily manipulated and they are shown as more radical in the media than some actually are.
We need to go back to when we understood that people are individuals with their own thoughts and opinions, and that grouping people simplifies an individual dramatically, allowing hate and prejudice to fill in the blanks.
Change my view if you believe that the current way society identifies people actually benefits us in any way. | It depends on helping who? Labels help politicians to dehumanize the “enemy” and getting their own faithful to the polls. We are living in time when political discussion is focused on turning out the voters, not changing opinions, and scaring people by pointing out vicious “feminists” or bloodthirsty “gun nuts” gets voters excited. | 14 | 124 |
ELI5: Why do potatoes not taste sweet, while other starchy foods like corn and squash do? | Edit: I know the difference between simple and complex carbs, but corn and potatoes are both composed of starch, so why is the corn sweet? | Potatoes grow underground and are used to store nutrients for plants: they're basically really fat roots. Corn and squash are both the reproductive "fruits" of the plant. Starches and sugar are both made of the same molecules: carbohydrates. The only difference is that starches are several thousand times larger, which allows them to store nutrients denser and more efficiently. | 61 | 86 |
ELI5: If electricity from natural gas power plants cant be stored, how do they know how much electricity to produce per day and where does the wasted electricity go to? | Lots of ways of making electricity have different benefits - nuclear is cheap but not very responsive if you need to increase or reduce supply, hydroelectric is expensive but very responsive, everything else is in between.
Power companies work HARD with big users in industry to manage the supply - for instance historically in the UK there are three 30' slots per year where domestic demand is so high that industry (eg foundries) can save a lot of money by keeping powered off during that slot (they pay variable pricing for power, btw).
What the grid needs is to know demand and be able to level it best possible. To do that, the spare electricity from cheap nuclear overnight is used to pump the hydro plants water back uphill, or if there's a surge in demand (kettles going on at half-time in the football), the hydro plant can be brought online at almost no notice to cover a surge. Gas plants take a littler longer to adjust, maybe a minute or so, so they can be brought up to cover the increased demand after the hydro has covered a gap at a price somewhere between the two. | 26 | 33 |
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What exactly are hash tables? | I’ve recently watched a couple videos of live programming interviews and in almost every one hash tables get brought up. Sorry if this is a really basic question but I can only get convoluted answers from googling hash tables. If someone could ELI5 hash tables it’d be much appreciated! | Imagine you have a mapping of usernames to user information like this:
* johndoe1 → (name: "John", email: "[email protected]")
* alice → (name: "Alice", email: "[email protected]")
* etc.
You want to be able to do a *lookup* of a particular user using their username. The username, being unique for every user, is called a *key*.
If you were to store this information naively, as an array for example, then a lookup would require you to go through the list one-by-one and compare the username to the the requested username for each entry. So in the worst case (if it's the last one) you'll need to go through the entire list until you hit the user you're looking for.
A hash table is a data structure that allow you to do lookups much more quickly. You create an array of a certain predetermined size (let's say 256). And then you "hash" the username to some index between 0-255. So "johndoe1" might hash to 132, "alice" to 42, etc. And you store the user information at the corresponding location in the array. There are many possible hash functions, a good hash function will be as random as possible but will always hash each input to a fixed hash.
Now, if you want to do a lookup of "alice", you just hash that username to get 42, and then you go straight to the corresponding array index: `users[42]` is your user entry.
A problem here is, since there's only 256 possible "slots", what do you do if you get clashes (for example if there are more than 256 users there must be at least one clash). This is called a hash collision, and there are multiple ways to solve it. Most commonly you will just gather all the users with the same hash in a list, and then go through that list the "naive" way. | 38 | 32 |
Why is hydraulic fluid so toxic to humans ? (questions stems from recent pics of a NSFW hand that was operated on to remove high pressure fluid from a leak) | Aircraft hydraulic fluid is phosphate-ester based. Phosphates dissolve oils very well; they were a standard component of electric dishwasher detergent until recently, when they were removed over groundwater pollution concerns. It's chosen because it's incompressible, less dense than oil (lighter), and is very temperature-stable.
Automotive brake fluid, on the other hand, is based on glycol ethers. In this case, the composition is chosen for its very high boiling point and thermal conductivity. In a passenger car the brake fluid might see a temperature of 400F; in a race car 500F+. Glycol ethers are a common solvent used in paint, and they are very hygroscopic (absorb water) which makes them a skin irritant, but their toxicity is considered low. | 171 | 340 |
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ELI5: What keeps time moving forward? | As I understand it, we're in a 4-dimensional universe, where time is one of the dimensions. Although the spatial dimensions are constant, time always keeps moving forward. Why is that? | What is time? Can you fill a cup with it? Can you measure out a piece of time and give it to someone? How do you know time has passed at all?
The easiest to understand description of time I've ever gotten is: change. You perceive time because things change. Simple observable things like the sun moving across the sky.
But also very complex things like the way you age. Atoms decaying. All the chemical reactions that make up existence going about their way. Using up elements, creating new elements from those reactions.
If nothing happened, if nothing changed in any way, if the universe was frozen in a state of sameness... would time still be passing? Not in your perception.
So why does time only move in one direction (or at least why do you perceive time to only move in one direction)? Well have you ever made a cup of coffee? Boil the water while steam escapes. Percolate the hot water through the coffee and the filter, mixed in the milk, dissolved the sugar, drank the coffee. Have the drink go through your digestive system and pee out the waste.
It's easy to do but hard to undo. You can experience that sequence of events in one direction but you can't undo it to arrive at the original state where the coffee is in the jar, the water is in the machine, the sugar is in the pot and the milk is in it's cup.
Time is like that. You experience it because you witness sequential change. But those changes can't be undone. | 26 | 25 |
Why do biofilms form? What is the mechanism bacterium use to communicate with each other in such a situation? | I thought prokaryotes were just a nucleoid and some ribosomes contained in a cell wall. When they form a biofilm, what the heck is going on?
After taking courses in biology, I came across this strange phenomenon. I've got a rudimentary understanding of cell biology, but I'm still confused as to how such simple structures as prokaryotes can perform hive mind actions like forming a biofilm. | Quorum sensing would be the correct term here. A bacterium can detect the presence of other nearby bacteria because they secrete a ligand. This chemical signal is receive by the sorounding bacteria, and depending on the concentration of this signal, different actions are taking.
This type of activity is also exhibited when bacteria form single layer formations. Let me know if you need a more detailed explanation of how bacteria communicate chemically. | 10 | 16 |
ELI5: How does the 'good bacteria' in Yogurt or Sauerkraut survive gastric acids? what percent of it is alive before reaching the gut? | The bacteria in question have adapted to live in acid environments and even make their environments sour in order to kill off other bacteria so they can consume all the nutrients. So they have an easier time getting through the gastric acid then most bacteria. And you are right that the gastric acid is not fully efficient and some bacteria will get through. It is hard to count these and there are a lot of variables involved. But some bacteria might be in a clump of yoghurt that does not dissolve before it goes straight through your stomach. Or the bacteria might be able to hide in the crevices of the musli you eat with it. On the other hand adding sugar or grain to the yoghurt before eating it can get the bacteria to come out of hibernation and take down their protective shell making them less resistant to the acid. But the stomach is not the only thing protecting you from bacterial infections. The existing gut flora will attack any new bacteria. So when the stomach acid have gotten rid of most of the bacteria the rest will be easy for the gut flora to handle. So even though yoghurt might help replace a weak gut flora we would not expect it to have any effect on normal people. | 17 | 24 |
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ELI5: Why is shower discouraged after massage? | Usually, massager says to avoid the cold entering our body. What's the explanation behind this? | * The point of massage is to loosen tight muscles and increase blood flow in the massaged areas.
* When an area of the body feels cold, muscles contract and blood vessels in the area are automatically constricted to prevent energy loss.
So "cold entering your body" when showering would immediately end and reverse the effects of the massage. | 32 | 16 |
ELI5: How can cars like the Honda CR-X get 52 mpg in 1984 but average cars now get the mid 30's? | Explain? | Weight and Emissions requirements.
Cars have progressively gotten heavier for safety reasons such as mandatory air bags, and higher crash test requirements.
Car engines also have much more restrictive emissions laws influencing their design. Things like catalytic converters affect horsepower and efficiency. | 38 | 39 |
Does DNA store meta-data about its history? | i.e. are there any segments of the DNA strand that might give away information about how the DNA has changed over time and, if so, how and where are these situated? | If you mean meta-data as in data-about-the-data way, then yes. This is called epigenetics. Generally, its used to switch off genes where they arent needed e.g. eye creating genes in your spleen. Its also possible to pass on the epigenetics effects that the environment has on your DNA though. So if a woman who is pregnant with a baby girl goes through a period of starvation or is exposed to a pathogen, this will alter the epigenetics of the eggs forming within the female fetus, causing altered gene expression two generations hence from the initial stimulus. you can see that when you test for position of epigenetic markers. There are other ways epigenetics are used but they get very complicated so Ill skip those for now. | 70 | 228 |
ELI5: How did the US tax code become this complicated? | Thinking about April 15 coming up, and the entire multi-billion dollar industry that's sprung up around tax preparation, tax evasion, paying as little as possible, etc. I think back to 100 years ago, and I can't imagine life in 1915 re: taxes being this complicated. Even less so 100 years before that, when we probably just dropped some coins off at the post office or something (who knows). Is there an ELI5 answer to the evolution of the tax code, and how/why it became necessary for the IRS to be so complex?
**edit** April 15 is tax day, April 4 is my parents' anniversary. | What started as a simple system had extra rules grafted onto it over the years to help out various special interest groups, government program and to influence people's behavior without passing overbearing laws. Add 50 new rules a year for 100 years and pretty soon you got yourself a whole mess of rules. | 44 | 100 |
I don't believe that TeX (like LaTeX) is a useful typesetting tool for humanities disciplines and that the time it would take to learn how to effectively use it is not worth the benefits of using it. CMV | I believe that using a TeX editor has a ~~steep~~ prohibitive learning curve and is not very user-friendly or intuitive, and while indispensable for writing equations, it is not nearly as useful in humanities as most of publishing in those disciplines is straight text with referencing which can be easily managed in the usual text editors.
While TeX editors are generally free, so are Office alternatives like OpenOffice etc. so I don't think that is a specific advantage.
Given that TeX is difficult to learn - that it's a light version of programming code, I don't think that there is any overall advantage to learn how to use Tex when the other common text editors work straight out of the box.
Please CMV.
Edited for accuracy.
**My view has been changed!**
Thanks to every one who replied.
Special mentions go to:
/u/zardeh for pointing out that complex texts that use lots of formatting are almost compelled to use TeX because other word processors don't cut it - and that I've probably been making my writing fit into Word's limitations, rather than having a processor that has functionality to achieve what I want for the final product.
/u/nurdinator for showing that LyX is a program that helps bridge the gap between what most people are used to in a word program and TeX, and that Word programs are usually incredibly frustrating - it's just that we are used to how frustrating they are.
/u/NeutralParty for making me realize that it's actually *not* like learning code, it's just using tags for flagging formatting - and the basics are not that hard: if you can use formatting in Reddit, you aren't too far away from TeX.
I'm happy to report that I'm dipping my toes in TeXMaker for Linux (since I'm making the change, I thought I'd dive into the deep-end and see if I can swim.) There is a transcript that I have been working on which has required extensive footnotes and it turns out that it's really simple to make them and the formatting of them is perfect. I think I'm going to finish up the editing of the transcript in TeX and see what comes out of it.
I haven't quite ventured out into setting up a bibliography with BibTex (though it sounds really promising), but I've already started using packages. *Todonotes* has some really cool functionality to make notes on documents - it's the kind of function that the annotation that other word processors don't have. I like that I can have a bright, clearly noticeable annotations that persist on the document until they are resolved. You can even make a page that indexes all of the todo annotations. This is pretty good.
I think I'm already a happy camper. Just a little more practice at this and I think I'm going to be trying to convert other people to the TeX-side.
(I've messaged the mods about the missing deltas too.)
Thanks everyone! | One of the biggest advantages of TeX is global, highly flexible formatting. You can change a few lines in the preamble of a TeX file and completely adjust the format of an arbitrarily long document. This is beneficial regardless of what discipline you're in.
TeX is actually quite a bit *easier* when you're *not* writing equations. You spend the vast majority of the time just typing in plain text, and typically can set the formatting up at the end. Often you can just look up whatever TeX-specific features you need as you need them. This is less true of equation editing, which would be too time-consuming to do this way.
When publishing papers in journals in disciplines where TeX is popular, you don't even set the formatting yourself. Instead you just give them the raw TeX file and they insert their proprietary macros to format it for you.
BibTeX, a system for generating bibliographies, is indispensable for citing sources, partly because many databases can give BibTeX exports of the citations of their articles directly. Like the preamble, you can change citation formats throughout the entire bibliography by modifying a single line. You also can't make a formatting error in your bibliography provided you include all of the information, because BibTeX writes the actual bibliography itself for you: all you do is supply the information, labeled as title, author, page number, etc. | 21 | 19 |
ELI5: Why does drinking water not always help with dry mouth? | It takes time for water to make it through your digestive tract where it can be distributed to cells via blood. Water in your mouth will *rinse* your mouth, but it won't get the water *into* the cells themselves to a significant degree. | 19 | 21 |
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ELI5: When you rub your eyes and see rainbow colors and swirling patterns what’s really happening? | Pressure can stimulate the cells in your eyes that usually respond to light. As a result, even though there *isn't* associated light, they fire off signals to the brain.
The brain doesn't have any way of sorting 'light' signals from any other that come from those cells, so it just says "Ok, I'll paint the picture!" and creates an image based on what it receives. | 56 | 28 |
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How do polarised lenses block the glare from water? | Light wave energy can oscillate up and down, side to side, or any angle in between. The molecules in the lenses or lens coating allow only one angle of polarized light to pass through and block all others. If the angle is chosen to allow all vertical oscillations to pass, then any horizontal ones are blocked. Light glancing off water at a low angle are primarily horizontally polarized. | 28 | 17 |
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Why do nuclear reactions emit electromagnetic waves? | Mass converted to energy through e=mc^2 is in the form of kinetic energy and electromagnetic waves, now my question is why they form electromagnetic waves? | Disturbances in electromagnetic fields manifest as electromagnetic waves. It's usually the movements of electrons that we associate with these disturbances. Protons, being charged particles, can also disturbe electric fields when they move/change in nuclear reactions. | 12 | 47 |
ELI5: How do undocumented immigrants in America survive and hold jobs? | I don't really understand how an undocumented immigrant is able to survive (get a job, get a place to live, bank accounts, etc) here. Most of those things require a social security card or proof of being a citizen I thought. | There are a couple ways to get a job: find under the table work that pays cash, doing things like manual labor (construction, landscaping), domestic work (house cleaning, nanny, caregiver for elderly), migrant farming, or find a place like a restaurant that will overlook your status; become an entrepreneur and work for yourself, as a handyman, scrapper, selling at flea markets, selling tamales, etc. There is also a market for fake/forged social security numbers where workers get paid above board, but will never end up being able to collect the social security they're paying into.
They stick to cash, use currency exchanges instead of banks, typically rent from other immigrants or smaller scale landlords who will not run credit checks and take cash for rent. A lot of these are not all that different from how many other poor Americans live, say those who have very low incomes, criminal pasts, poor credit and so on. | 17 | 15 |
If sound can be cancelled by producing another sound-wave in anti-phase, and light is packets of waves, is it possible that light can be cancelled out using anti phase? | Yes, all waves, including sound and light, experience destructive interference when two coherent waves meet out of phase. This is what leads to optical interference effects such as the swirling colors on soap bubbles, the colors on peacock tails, the color patterns on the bottom of a CD, etc. The reason that you see color patterns when interference happens is because different colors have different wavelengths and experience destructive interference at different points. So at one point on the soap bubble, the green light has the right wavelength so that the reflection of the front surface of the bubble's thin film interferes with the reflection from the back surface of the thing film, destroying the green light, and leaving the red/blue light to reflect back into your eye.
Note that in wave interference (true for both sound and light), energy is never really destroyed. Rather, energy is redirected by the interference effect to the areas of constructive interference (and/or absorbed by materials and turned into heat).
Also note that unlike sound-cancellation headphones, light cancellation goggles (i.e. sunglasses) don't use wave interference as the mechanism to block light since it is so much easier and practical to use simple absorption.
UPDATE: As others have wisely noted, mostly only low-end optical filters use simple absorption, whereas high-end filters indeed use the interference that happens between the multiple reflections of the incident light off of the layers of optical coatings. | 48 | 34 |
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ELI5: What does it mean to die of "natural causes?" | It's mostly a distinction used in the legal profession. Technically being eaten by a lion is a very natural way to die, but we wouldn't call that natural causes.
A cause of death can be accidental, murder, disease, or natural causes.
Accidental is you fall off a bridge.
Murder is somebody pushed you.
Disease would be something like cancer.
Natural causes would be something like heart failure due to advanced age or declining health.
We have a limited life span and as you get older, the chances of you not recovering from an illness go up. A 40 year old may have the strength to fight off a cold, but an 80 year old may not.
From a legal stand point, natural cause is a blameless death where as accidental, disease, or murder would have a cause and somebody or something to blame (even if it's yourself). | 41 | 32 |
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How are underwater cables laid? Plus other related questions in the text. | I understand that This has occurred since the days of the telegraph and now with the internet and so on. But I wondered how the process laying the wires is undertaken. What do the wires look like, is there protections against marine life, pressure, conditions down there.
Do they wear out? Is maintenance done? How are they upgraded/replaced?
What determines the best location for the routes? Is it simply shortest distance? Is there any consideration of the layout of the seabed or anything like that.
How do people know they are in the right place? What are the costs of these operations? Are there companies which specialise in underwater cabling? Does there have to be special political permission between countries where the wires connect and the waters they cross? etc etc.
Infographics would be greatly appreciated as well.
Thanks. | Seabed cables and pipelines are very complex, and to answer all the questions you've asked would take the better part of a 100+ page technical report.
In short, cables are typically manufactured in protective, elastic sheathes, designed for the operations conditions (depth, etc) and deployed by spool from the back of a ship, generally with some subsea monitoring (ROVs, divers etc.) Typically many spools would be required, so each cable is attached to the previous on in situ, before being rolled off into the ocean.
In some circumstances they are buried to protect from seabed scouring, or other potential damaging items (anchors for example).
Maintenance or retrieval would be more expensive (in most cases) than replacement.
Politics are important. Each country owns a set distance of seabed from the coast line, and international agreements/treaties/permits are required.
Routing is done via economics. The cheapest solution is usually the one chosen. However this may be impacted by the need to bury the lines, and operational requirement for deploying the cable(s).
Deployment is done via GPS, and yes, they are crazy expensive. You need specialized ships for often months at a time. Chartering ships gets you into the millions of dollars pretty fast, never mind manufacturing costs and required technical expertise on board. Add in the time/man hours you need to complete the design, approve all the permits and get the ball rolling. Weather can impact operations significantly, so you need to account for scheduling risk etc. etc. etc.
TL;DR: Subsea cables are laid very carefully.
| 18 | 49 |
Why is fluorine more electronegative than nitrogen? Than bromine? Why is hydrogen so weird? | for reference:
http://www.chem.umass.edu/genchem/whelan/class_images/111_Electronegativity_Table.jpg
I feel like no one bothers to learn about electronegativity in terms of basic physics, they just accept electronegativity as a fact and that "puzzle pieces like to fit together in Lewis dot diagrams". Can anyon offer me a more rigorous explanation of electronegativity? | Electronegativity is how strongly a particular atom attracts electrons.
To understand what that means, you need to know what attracts electrons, and what factors can affect that.
Electron orbitals have very specific shapes in 3 dimensions, and can be thought of as a waveform. These waveforms are most stable when filled with an appropriate number of electrons. The first valence shell is *s* and the first level of the *s* orbital prefers 2 electrons, this makes it most stable. Hydrogen is nothing more than a proton and an electron, but it is very stable when it can fill its valence shell with 2 electrons, hence a high electronegativity and why it is so weird. Helium has 2 protons and 2 electrons (and 2 neutrons, but they don't matter for the moment), so its valence shell is full at 2 electrons, and it does not attract electrons to fill and sort of void, and therefore has a low electronegativity.
Now, we talk about ionic forces.
Electrons are negatively charged, and as such they are attracted to positive charges, such as the nucleus of an atom. The force of ionic attraction is proportional to the charges of the two objects, and inverse of the square of the distance between them. The higher the positive charge of an atomic nucleus, the stronger the force of attraction, and the smaller the distance between those charges, the stronger the force of attraction.
As you move from the left to the right of the periodic table, you have more and more protons, which means an increasing positive charge in the nucleus. This increasing positive charge exerts an increasing force of attraction on the electron orbitals. This causes the **size** of the orbital to **decrease** as you move across the periodic table. This is why the **electronegativity increases going from left to right.**
Now to add another concept.
Valence shells exist in orbitals that have different levels of energy. The fact that energy is discrete (dividable down to quanta) means that the orbitals have discrete levels, or layers. Not only do more layers increase the distance between the nucleus and the electron it is attracting, but those layers are all negatively charged and will act to repel another negatively charged electron.
This is why as you **move down** the periodic table (increasing levels of valence shells), the **electronegativity reduces.**
Now remember that we talked about valence shells being most stable with certain numbers of electrons? The next 'magic number' of valence electrons that make the orbitals stable is 8. Now count over from left to right on the table. Florine has....**7** electrons in its valance shell, just one short. It strongly attracts that last electron not only because it is small and has a large charge in its nucleus, but because gaining another electron makes it have a **more stable** valence structure.
OK, so we've talked about what electronegativity means, and what factors have an affect on it, but why do we care?
We stated that a stable valence shell has 8 electrons. This is why Carbon, with 4 electrons in its valence shell, will make 4 covalent bonds. Covalent bonds, as their name suggests, are when 2 atoms **share** an electron so that **both** atoms can have a stable valence shell. in the case of a covalent bond between atoms that are the same, the electron is shared equally, because the **electronegativity** of each atom is the same. However, if one atom in the covalent bond has a higher electronegativity, the electron is attracted more to that side of the bond. What happens when you're attracted to something? You want to spend more time there. Because of this unequal sharing, the bond becomes **polar**, in that one side of the bond has a slightly negative charge, and one side has a slightly positive charge.
This matters in incredibly significant ways. Water, for example, is a polar molecule. Because of this water is liquid at room temperature, held together by hydrogen bonds (a consequence of polar molecules). DNA is also held together to their complementary strands by hydrogen bonds.
edit: the stability of 8 valence shell electrons are also why the noble gases are very unreactive. They do not need to share electrons to be stable. The low reactivity of this group of elements is why they are called 'noble', as nobility kept to themselves.
| 97 | 225 |
ELI5: Why can't fresh water fish survive in salt water, and vice versa? | Many fish can, and do. Salmon, for example, make babies in fresh water. The babies swim out to sea and grow up and get big and strong, and then they come back to fresh water and make more babies. They have this ability because over millions of years, they were able to have more babies in freshwater than saltwater. That is, they evolved to take advantage of reproduction in a freshwater environment. The fish that can't do this made babies just in the ocean or just in freshwater, and so never had pressure to evolve to be able to tolerate both environments.
A fish's body wants to have an amount of salt inside it somewhere in between the ocean and a river. The way both kinds of fish's bodies do this is called *osmoregulation*. So a freshwater fish will get its salt from its food, and it makes its pee super watery, or diluted, so there is more salt inside than in the water. A saltwater fish gets too much salt just from living in the ocean, so it makes its pee super salty, or concentrated, so its body is less salty than the water. Most saltwater fish can't live in freshwater because they only knows how to make their pee concentrated, so they'll lose all its salt. Most freshwater fish can't live in saltwater because they only know how to make their pee more dilute, so they'll get too much salt.
| 30 | 21 |
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In laymen's terms, why does splitting an atom release so much energy? | Most interactions we see in our daily lives are due to electrons - electricity and chemical reactions. Electrons are really small, light particles, and the forces keeping them in the atom is only strong enough to keep them in a (compared to nuclear scale) quite large cloud around the nucleus.
Nuclei are made of protons and neutrons, which are approx. 2000 times heavier. The forces keeping them in place are necessarily much stronger, and therefore have more energy associated with them.
But it doesn't necessarily follow from the above that splitting an atom should release energy. If the forces were simple attraction, it would be hard to split an atom, and there would never be any energy given off. But the forces involved are more complex, and only relevant at very short ranges, more like glue than an attractive force. When you break the glue, the resulting particles repel each other strongly, and move apart with a lot of kinetic energy. Electromagnetic energy may also be released directly as gamma rays.
Of course, splitting one atom doesn't release monstrous amounts of energy - the reason an atom bomb works is because of the domino effect, a cascade of atom-splitting that multiplies and multiplies until the available fuel is used up. Imagine a tree structure where starting one domino at the top sets off 2 lines, then 4, then 8, then ..... then 2,000,000,000 dominos simultaneously. You may think it's a huge jump from 8 to 2,000,000,000, but it's not as big as you think. | 456 | 838 |
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If I swallow a large piece of food, will I still digest all of it? | I've have some idea how food moves around inside the body and some about the timeframes, but I've no idea of the capabilities and mechanics of the system.
Are large pieces of food broken into smaller pieces chemically somehow and then digested? Or does digestion happen layer-by-layer, no matter the size of the object? If so, will it just continue until it's all gone? | Digestion has a few phases. Your mouth begins the first part, where saliva breaks down starches. The stomach is next, which has two primary methods of digesting food: acid mostly kills bacteria, but does help to break down the structure of food. Pepsin is a very active digestive enzyme in the stomach that is activated by the acid. Primarily though, your stomach is a muscle, and churns the food to break it into pieces. Big chunks of food simply won't proceed out of the stomach after this: if you swallow a big piece of meat whole, it will slowly break apart in your stomach and won't move as a chunk into the intestines.
Your intestines are where the "real" digestion occurs. Bits of food (at this point called "chyme") are squirted through the pyloric sphincter into the intestine. Here is where we see real protein and fat digestion occur. Most nutrients are actually absorbed within the first foot of the intestine, fats take longer and are broken down and absorbed over the first few feet. The small intestine are where the primary enzymatic breakdown of food occurs; the stomach is mostly a preparatory step but is not a good environment for most protein activity (because it is so acidic). | 22 | 37 |
[The Orville] Why is pop culture from the 21st century so important in the 25th century? | Every Earth based member of the crew, including and especially the captain, make references to 21st century pop culture, music, and art. Did culture stop producing humour? Why the emphasis? The oldest cultural references I can think of all reflect geniuses like Shakespeare, Leonardo, Mozart, etc. so is it implied that the 21st century was the peak of pop culture? If so, why do their references stop in the earlier 21st century and don't bring up events in the late 21st century? | You would be surprised at what informs our pop cultural references, and use of phrases in everyday language, from the Bible, to Aesop's fables, and various Greek plays.
We also have things like the SCA which actively work to promote older skills and art forms.
Finally, we have way more video references of current popular culture than we do of past works, which means things will likely last longer in public awareness. | 43 | 55 |
ELI5: How can a psychological factor like stress cause so many physical problems like heart diseases, high blood pressure, stomach pain and so on? | Generally curious.. | None of these responses seem at the ELI5 level. Let me try:
"Stress" is your brain thinking there is a threat and telling your body "do what you have to so you can get through *right now* and we'll sort it out later." So your body floods itself with chemicals that it thinks will help you overcome whatever threat the world has thrown at you - this is when people talk about "super human strength" for example.
The goal of this is to fight off a bear or out run another predator. These chemicals that get dumped into our body are highly toxic to us in the long run, but what does that matter if you die to this threat *right now*?
The issue for public health is that your brain is setup for living in the wild and doesn't know that an unexpected meeting with your boss is not a threat to your life. So now we have a situation where we are constantly dumping toxic chemicals into our bodies for prolonged periods which causes all the problems you mentioned. | 9,601 | 15,807 |
CMV: While I admit that I have privilege, I still don’t see why everyone insists on me acknowledging that fact | Sorry for the weird title but I couldn’t think of a better way to phrase it.
I’m white. I’m male. I’m straight. So yes, I have privilege and I’m totally fine admitting that. So now what?
That’s really the question that I wonder whenever people bring this up. Like yeah, I have privilege but since I’m not the god-king-emperor of the planet there’s not much I can do about it. I can’t stop other people from being racist or sexist. So I always wonder why everyone seems so adamant that I admit to having privilege.
It doesn’t change the fact that I still worked hard to get where I am, nor does it change the fact that I will continue to do so. Like, I’m also pretty privileged to have been born with functioning kidneys but that doesn’t mean I have to give a kidney to someone with a disorder.
The thing that really confuses me is that people don’t phrase this like it’s just a fact of life. Like, they don’t just say “you have privilege” the same way they say “oh the sky’s blue”. To many people it seems like there’s a lot more.....fire behind it. Like they would get legitimately angry at me if I denied having privilege which makes no sense because once again, *the knowledge that I have privilege doesn’t change my behavior at all*. Like I said, it’s not like I’m gonna give all my money to black people or something like that.
So CMV. Maybe there really is a reason people are so adamant on this topic? | There are two views on privilege, and you hold the first of them.
1. Everyone has inherent privileges: IQ, good/bad parents, height, explosiveness, country of birth, etc. These exist, and there's not a lot we can do about them.
2. Everyone starts the same, and privilege is a result of oppression.
The second view is very common. If you hold it, then privilege is "unfair" in a preventable way. Not in a "life is unfair" way, but in a "if you weren't oppressive, others would be better off" way. Many of the people who vindictively want you to admit your privilege believe that a hypothetical world exists in which your privilege doesn't, and therefore we should be aiming at that world. In order to aim at that world, everyone needs to acknowledge that we're not in it.
This is the fundamental difference between your viewpoint and the people you're referencing: you believe that privilege is unavoidable, and they don't. That's why it's so important to them that you acknowledge it, because on their worldview, it can be changed on a broad scale, and acknowledgement is the first step to that. | 37 | 37 |
Why is sitting bad for us and how often would a human/primate sit naturally? | Hm, this might be a strangely-worded question.
We've been hearing a lot about how sitting is (or can be) causing so many health problems because how stationary our lifestyles have become.
I guess I'm a bit curious as to why sitting is such a health risk. Is it only because the amount of exercise we get throughout the day is limited? (spending more time watching television, video games, computers, sedentary occupations-less time outside walking, running, exercising)
Or is sitting itself causing issues?
If humans were not exposed to technology or jobs that require regular sitting, how often would we be sitting? Is there a difference to how and how much we sit now compared to our past ancestors and other primates now?
As someone who works in animation, I do a lot of sitting which got me thinking.
Anyway, thanks to any and all answers!
| Sitting, as it turns out, has played an important role in the evolution of our species. In fact, our body structure is well designed for sitting.
Not just us either. Resting is an important part of what all animals do on a day to day basis, and we all have strategies for doing it to our best advantage. Songbird feet, for example, are built in such a way that when weight is placed on the foot, the weight of the bird tightens the tendons of the foot, and the bird can perch without using any muscle strength.
Compared to monkeys, Apes spend less time lying down or hanging and more time sitting. As a result, all apes execpt for humans have what is called an ischial callosity, a large callous on their ass that allows them to sit for long periods of time without getting ass-chap.
Humans take it a step further than the rest of the apes. Because we walk upright, we need large muscles on our ass. We fill these muscles with a lot of fat on purpose because it helps us sit comfortably for long periods without bruising. We are built to sit.
So why is sitting a risk factor for heart disease, stroke, high blood pressure, diabetes, and a whole host of other epidemic conditions? The answer: we spend too much time sitting and not enough time walking. As much as humans are built to sit, we are built to walk, AND RUN! We should naturally spend a good portion of our day walking and running. EVERY DAY! But we don't. Most of us sit too much and eat too much, and that's why the statistics suggest that sitting is a risk factor.
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tl;dr sitting isn't bad, what's bad is not being active enough.
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PS: There are ways sitting can be bad for you. Especially among elderly, it has been noted that long flights can be a risk factor for thromboembolisms (essentially a blood clot that forms somewhere in your distal arteries, makes its way to your heart and beyond). Such long periods of sitting causes the blood in your legs to circulate less. If the blood pools, it can clot, and those clots can disrupt the function of your heart or brain if they find their way to either of those places.
However, if you have been getting good exercise lately, this shouldn't be a problem for you, as your strong heart will continue to move the blood through your legs sufficiently for the duration of the flight.
Edit: Breaking up your sitting episodes to walk around a little can certainly go a long way. | 281 | 395 |
ELI5: How can a fighter jet force a (kidnapped) airliner to land? | Threaten to shoot it down? That wouldn't be very wise. | Wise compared to what?
It's definitely better to kill everyone on the plane than let the plane be used as a missile and kill everyone on the plane and everyone in a 100 story building.
300 deaths is better than 3000 deaths.... | 46 | 33 |
Why is there much more of certain elements compared to the elements next to them on the periodic table? | My basic understanding of how elements are formed is that the heavier the element, the more energy is needed to create the conditions for it to be formed. So I would expect the occurance of elements to be pretty much descending the heavier the element is. But, looking at the webpage sourced below for the universes makeup, that's not so. For example, there's a lot more carbon than boron, much more oxygen than fluorine, and much more iron than maganese or cobalt. Why is this?
http://periodictable.com/Properties/A/UniverseAbundance.v.log.html | There are two things that affect the abundance of a given element in the universe: the stability of the isotopes of that element, and the rates of production/destruction.
If you have some element whose isotopes all decay very quickly, it will generally not be very abundant in nature, unless it’s being produced at a fast rate.
Or if you have an element with many isotopes near stability, but no astrophysical/cosmological process is able to create them in significant amounts, they won’t be very abundant.
Each element has many isotopes, each with its own ground-state half-life (ranging from ~ 10^(-22) seconds to infinite), and each with its own methods of being produced and destroyed in nature.
So you have to calculate threough a complicated network of many different nuclear reactions, at different kinds of astrophysical sites to determine the final abundances of elements that it will produce.
There is no general rule, like “lighter elements are more abundant”. There are peaks and valleys all throughout the distribution due to nuclear shell structure, etc. | 34 | 30 |
ELI5: The difference between Kosher and Halal. | Assuming there is more to it than "One's for Jews, one's for Muslims" | 1. Halal excludes alcohol, Kosher doesn't.
2. Slaughtering practices are different.
3. Mixing meat and dairy is not Kosher, but is okay for Halal. This one can be taken very seriously, banning that the two be consumed in the same meal (if you had steak, no ice cream for desert), even to the point of having separate dishwashers, sinks, plates, etc.
4. Halal allows shellfish (depending on the school), Kosher doesn't.
5. Halal allows a broader range of meat (basically, it has to be totally herbivorous); Kosher requires that it has cloven hooves and chews cud. | 25 | 25 |
ELI5: How do people plant trees in the millions on such short notice e.g. like on environmental events? | Surely they don't manually plant each seed one by one?
| In the forestry industry an experienced planter on fast ground (i.e. flat, soft soil, no logs/branches/brush in the way) can plant 3000+ trees per day. They nearly always get paid piece rate, hence they’re motivated to go quickly.
It’s hard work.
I would think that for those enviro events they get huge numbers of people to plant a couple of hundred each.
| 12 | 16 |
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