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ELI5: The practices/beliefs of the Jewish religion.

Judaism is a monotheistic religion - i.e., we believe in "One God", indivisible. The foundation of Judaism is found within the Torah (a.k.a. the old testament) wherein you will find every law (halachah) that a Jew must follow. These are referred to as "mitzvot". There are 613 Mitzvot. These concern everything from dietary law, to dress, to marriage and death. A significant portion of mitzvot concern laws related to the Sabbath. The hebrew calender is neither lunar nor solar. Technically, it is a combination of both. There are 13 months but sometimes there is a leap month. Jews are huge on life cycle celebrations (birth, bar mitzvah, marriage, death) and have many, many holidays. There is only one Jewish month without a holiday. The most important holidays are pesach (passover) and yom kippur (the high holy days refer to the 10 day period before yom kippur). Passover commemorates the exodus from egypt (moses and the israelites) and Yom Kippur is the day of atonement - supposedly, when God writes in the book of life your fate for the following year (this is why you atone).

[In Time] How would a time based economy actually work?

"In Time" money is replaced by well.. time. After there 25th birthday people stop aging but they have to earn time to actually continuing living . This is all supposedly to stop overpopulation but the economic actions shown doesn't make any sense, if it where truly to control overpopulation time would be distributed based on overall population density but prices are raised arbitrarily (sean especially after Will and Sylvia flood the system with stolen time) suggesting that the real purpose of time based economy is to work pour people to death and to keep them from uprising against the system because well they don't have the time to stage a rebellion. So how would a fair time-based economy look like?

There would be enormous pressure to conclude schooling before the age of 25. This would damage many professions with extended education/training periods. Doctors would be rushed through their training. In a world without age-related issues, they'd be less in demand - except to treat trauma victims as billions of people spend decades continuing to enjoy extreme sports. Scientific research would be damaged, and any other even slightly esoteric discipline (like engineering). Aside from the technologies and knowledge needed to maintain the anti-aging system, we'd see a plateau in human ingenuity and training. You would think a world where geniuses stay young and vital would eventually balance this out with sustained creativity (as opposed to exhaustion) - but there's a mental element, not just one of raw stamina. Replacing money with time will make inequality much more starkly clear. Today, the average CEO makes 204 times what the average worker makes. That won't last in a time-based economy. In the beginning, you'll see a surge of retirements as people at the top gain what seems to be practical immortality after a few years. "I'll come back to work in a century or two." You'll see riots as people die in the streets while the idle rich become practically godlike. People with vital or disgusting jobs will go on strike until their true worth is known. That first year will be utter chaos. But at the end of it, the soldier on the frontlines will earn more time than the general who commands him. A garbageman will earn more time than an interior designer. Anyone whose job is enjoyable will see their work hours expand - while those whose jobs are not will work less. There will be a flood out of low-paying jobs into those who promise life.

Why is schizophrenia still being used when you apply the epistemology behind the word?

>Schizo = Split Phrenia = Mind The word schizophrenia translates as splitting of the mind, its use was intended to describe the separation of function between personality, thinking, memory, and perception. Japan changed this disorder's name to integration disorder in 2002, and South Korea changed it to attunement disorder in 2012. Does splitting of the mind describe the disorder appropriately enough to be used as the medical term, and how so? How would the aforementioned functions be separated in schizophrenics?

One reason names for illness change is often due to treatment options changing. Another is to make it seem less terrifying so people suffering from them are more likely to get help (which is why they did it Korea).

ELI5: Why do we feel tired after having to process a lot of information input e.g. a long day of learning new things from lectures?

We basically have different levels of relaxation or paying attention. When you pay close attention to things, your body increases its activity because something important is going on and you might have to fight or flee. Humans did not evolve to sit in lectures. So either your brain decides it is unimportant and you get bored and sleepy or it is important and your body prepares for action. In reality you probably cycle through those states throughout a day of lectures. Being in a heightened state of readiness is exhausting. So at the end of the day you are tired.

ELI5: Do human babies 'imprint' on the first person they see like animals? Or do we 'choose' parents based on other things?

Newborn babies recognize their mother / parents by the voices when they are born, having heard them for months in advance. Within days they also recognize the smell of the people taking care of them.

ELI5: World's wealth is growing at 2.5% rate. How is this possible? Where does "new" money come from if "everybody" is wealthier now?

Money is one thing, which /u/K3zzeR covered, but actual, tangible wealth is another thing that can also increase. With every person born, the world's labour force increases, and more work can be done. New resources can be discovered and used, new goods and services can be invented, automation can allow less workers to generate more products, etcetera.

is depression an illness?

One of my friend claimed depression is not an illness according to new classification system and actually a symptom of other things Is he right ?

Depression is a syndrome, that is, a collection of symptoms that tend to group together. The diagnosis doesn't say anything about what "caused" it, just what the symptoms should be. It depends on what definitions you use for "illness". But if you want to be strict about your definition, and say that an illness is some kind of disease process somewhere in the body, then depression is not an illness. This is one of the reasons why "disorder" is a preferable term to "illness" or "disease".

When applying Occam's Razor, how does one know what the "simplest solution" is?

For example, regarding the Theory of Evolution (which I believe, but I just needed an example)... The idea that over eons animals have various mutations that over time slowly change the organism ever so slightly, generation after generation, weeding out those mutations that don't help an organism survive until it finally becomes the animal we see today.... or God created a creature that fits perfectly in its environment. When I word the two options that way, the God option seems the "simplest solution". I never really understood how someone decides what the simplest solution is.

The explanatory economy Occam's Razor aims at is about economy of assumption-making. It's not about which explanation can be articulated in the simplest terms, or most briefly. "God did it" is a very simple explanation, but Occam's Razor still favors the theory of evolution, by comparison, because it's more epistemically modest, if you will. It explains the phenomena it aims to explain (species differentiation, etc) in naturalistic terms. Its assumptions are humble, based merely on the biological evidence around us. Whereas with "God did it", that supernatural assumption is a mighty big one. It's simpler, yes, but it's not more economical in epistemic terms, because one would have colossal difficulty in establishing God's existence in the first place.

ELI5, do we have any system of "direction" in outer space?

With everything moving and no obvious cardinal directions, how do we tell which way is which? Is everything just relative to what it orbits? With the message on voyager giving our "address" would other planets even know which way to go?

Let's just talk about navigating within the solar system. First, you have an easy direction - towards or away from the sun. Second, you pick a couple of fixed points in the sky, really bright stars that you can easily identify. With those 3 points you can determine your position anywhere in 3D space around the sun. This is how spaceships beyond Earth navigate in deep space. Traveling between the earth and the moon, the Apollo astronauts used star sightings and known landmarks on earth (like Cuba, Hawaii, Baja California, Madagascar, etc.) to determine their location. Modern travelers will use the sun + stars system. If you travel beyond the solar system but within the local group of galaxies, the best way to navigate is probably using pulsars. Pulsars are all unique - they rotate at varying speeds, and those speeds can be detected. Finding 3 pulsars in the sky, and having a catalog of known pulsar speeds would allow you to ID the three pulsars and triangulate your position anywhere in the galaxy. Essentially any time you can get 3 fixed points of reference in the sky, you can determine your exact position.

ELI5: What is a quark?

All I know is that it is very small... EDIT: This is what I saw that made me wonder about quarks. [Scale of the Universe](http://www.stumbleupon.com/su/2usPnU/primaxstudio.com/stuff/scale_of_universe/)

**Matter** (in the everyday sense) is made of **molecules**, which are made of **atoms**, which are made of _particles_: **protons**, **neutrons** and **electrons**. That seemed to be the whole story, and that the component particles of atoms were "fundamental" — they weren't made of anything else, they were just kind of themselves. But then we found out that **protons and neutrons are actually made of smaller particles**, which are called "**quarks**". Quarks have some interesting properties. It turns out that quarks have six different "flavors" -- just intrinsically different varieties. There are only a handful of stable combinations of flavors that will last when they clump together. Other combos break down quickly or never form at all. And most importantly and weirdly, they can't be separated — they can only exist in these combos. Particles made of combinations of quarks are called, as a family, "**hadrons**". The protons and neutrons we know so well from our daily lives are the most stable combination of quarks, which are made of just two flavors called "up" and "down" quarks. These are also the most stable flavors of quarks — other flavors quickly decay into up and downs. But there are also more exotic combinations of quarks that show up as relatively short-lived particles in cosmic rays and stuff. These can involve combinations of the other four flavors of quark: "strange", "charm", "bottom", and "top". Quarks and hadrons have a lot of other interesting properties and important roles in particle physics. But to everyday human experience, the combos of up and down quarks that we know as protons and neutrons are the biggest part of the picture.

Would it be better to neutralize an acid spill with a weak base or a strong base?

How you neutralize depends on the acid. If you spilled concentrated sulfuric acid, you're best off avoiding water and using something like solid calcium carbonate. If it's hydrochloric acid, you should dilute before attempting neutralization because HCl produces vapors when it heats up. If you spill something like hydrofluoric or perchloric acid, you run. Either way, you will produce less heat if you neutralize with a weak base instead of a strong base.

ELI5: Why lifespans differ from animal to animal.

There are two kinds of lifespans, more or less. Lifespan in the wild, and lifespan in captivity. Usually, lifespan in captivity is higher. There are no predators, most of the time you have people care for animals that know what they are doing. Lifespan in the wild is, especially the average, is hindered by predators and the availability of food. Let's look at lifespan in captivity: You have massive animals, like elephants, who have comparatively huge organs. They are built to last. On the other hand, you have animals that are smaller, but they are living really slow, like turtles. Generally it means, the faster you live, the shorter your life will be. ELI5: The size of the animal is the candle, the way the animal lives is the flame. Imagine a small candle with a huge flame, it burns down really quickly. Imagine a Large candle with a huge flame, it burns down normally. Imagine a Large candle with a tiny flame, it burns (almost) forever. edit: comparison updated

What is your motivation/ inspiration behind Economics major you are pursuing? What are problem-solver aspects of Economics major? Can it be used to build something? Or will it about mostly abstract things?

Please correct me if I am wrong and I am more than open to your advises. Maybe, you can enlighten nowadays' Economics students. Will try to less arrogant: I chose the major with the mindset that Economics is an interdisciplinary field and in the crossroad of Business and Technology. However, being sophomore undergraduate, I am somehow losing interest as I gradually feel that Economics teaches me the world as it is and kinda does not offer me tools to build something ( sounds egoistic i know but, I like to build, lead things). Building, creativity involving courses such as Microeconomics (Intermediate) fascinates me though. But courses such as Macroeconomics and Money, Banking& Financial Markets are so-so for me ( feel like retired grandpas watching economy news when I read them). once I& my friends thought about implementing startup idea, felt like useless major student and think that even Finance majors would be more useful in this case. When my uncle& dad suggest me to do research on some Economics topics (such as how can we improve our small nation in the Caucasus economically), felt like "what good will it offer me then?". I guess I kinda fond of science entrepreneurship. Fyi, I hear advises like thinking about ML, Data Science and Analytics. What is your perspective?

Economics is a science and, therefore, less directly applicable to generating profits than many other fields it gets grouped with. It is a way of thinking about the world as much as it is a toolkit of statistical tools to make informed arguments on almost any topic. It certainly can be helpful in business situations. Perhaps it's more helpful in policy decision making. It can certainly answer the questions you posed. Most people at the highest level of economics (as in people with Ph.D.'s) consider themselves scientists first and foremost. Most people at the top level of Finance or Accounting are probably C-suite level executives in large corporations. It is not likely to be as beneficial to someone with entrepreneurial aspirations as a more general business degree.

CMV: I believe that political experience is necessary for impactful legislation and high profile political roles and that USA's idea that an outsider will bring change is completely wrong

The 2 arguments behind my view are 1. Intuition - You need to understand how institutions work from the inside to use them to your advantage 2. Historical Precedent - For the last hundred years, the most lasting legislative impact has been cast by politicians who have had tons of experience **Positive Examples Of Experience Being Useful** 1. FDR - had 22 years of political experience and was able to make a lasting impact through Social Security and the New Deal. 2. LBJ - Had 36 years of experience and make a lasting impact through Medicare, Medicaid, and the great society. 3. Richard Nixon - had 2 terms as vice president in the Eisenhower administration ( Eisenhower was a political outsider and was getting old; thus, the vice president had more hands-on experience) and his policy on drugs ( whether we agree or not), China and the EPA has remained almost intact. 4. George H.W.Bush ( Slightly different example here) - Had over 25 years of domestic and foreign policy experience. Stabilized the world in a post Coldwar era i.e. avoiding any political vacuum that might have caused ISIS type instabilities in eastern Europe and successfully restored American Spirit in interventionism by winning the 1st war against Saddam Hussain **Negative Examples Of Inexperience Failing** * Robert Mcnamara ( Businessman, Veitnam) * John F Kennedy ( zero experience, bay of pigs) * Jimmy Carter(no experience, Iranian Hostage Crisis) * Bill Clinton (6 terms Governor and no Washington experience, inaction during Rwanda genocide) *George W Bush (3 term Governor, Iraq war amongst so many other quagmires) *Barack Obama( Junior Senator, political vacuum in Iraq leading to rise of ISIS) * Finally, Trump and Rex Tillerson(it may be too early but so far... Zero political Experience, not filling bureaucratic appointments leading to hollow and inefficient government and state department) Some background on myself to help you CMV * I am not an American but have been following American politics for a couple of years now, so there may be historical blindsights/ on the ground reality related blindsight in my perspective. * I happen to lean center of the left and may have confirmation biases here and there too. **Edit -** I seem to have changed my mind on quite a few issues from the scope of the presidency to the unknown achievements of many presidents. All in all, this was a good learning experience, thanks for keeping it civil.

It seems like your only metric for analyzing success and useful is "I can think of something good for these experienced people" and failure as "I can think of something bad for these inexperienced people". _Surely_ you have to have a basic understanding of confirmation bias such that you aren't actually really satisfied with that? How are you constructing your terms and analysis such that is Vietnam a hit against McNamara but _not_ LBJ?

[The Rock] Why did a civilian chemical weapons expert accompany the doomed Seal team during the raid on Alcatraz?

Surely the military has people who know how to dispose of chemical/biological weapons. Why not send one of them? Why did General Kramer tell FBI Director Womack to find his "best chemical/biological man?"

Chemical/biological weapons are extremely rare and the army concentrates its resources on the the most direct and applicable threats. Their research into chemical warfare extends to how they protect themselves. Any chemical weapons used on soldiers will be speeding towards them in rockets already. As was seen when weapons inspectors were sent into Iraq in the 1990s, the expertise lies in the civilian sector, scientists and people who devote their lives to understanding chemical and biological attacks and how to counter them. The FBI is more likely to be dealing with a chemical bomb, so it is more logical that they would have someone like Doctor Stanley Goodspeed on the payroll, who it should be noted had expertise across a wide field of topics. When the army needs someone that can get in and disarm VX gas–armed M55 rockets, they turn to the FBI as they have someone like Stanley on the payroll, he's likely studied that exact weapon and he's the person with the best chance of getting the job done.

[Independence Day] which cities were wiped out in first assault, and which in the follow up?

Capitals, major population centres and important military facilities were the first targets chosen. Landmarks were typically chosen to be ground zero for the impact their destruction had. After that, it was mop up really - at least until we kicked the shit out of them up and stole all their tech. Now when humanity goes about exterminating a filthy alien species to strip mine their world, we make sure to get all the little fuckers in the first strike.

How would Ancient Stoics deal with people who did not think, even remotely, how they did, and how would they help them if in emotional need?

Epictetus' Enchiridion chapter 16 has the following advice: > When you see any one weeping for grief, either that his son has gone abroad, or that he has suffered in his affairs, take care not to be overcome by the apparent evil; but discriminate, and be ready to say, "What hurts this man is not this occurrence itself,- for another man might not be hurt by it, - but the view he chooses to take of it." As far as conversation goes, however, do not disdain to accommodate yourself to him, and if need be, to groan with him. Take heed, however, not to groan inwardly too. So the basic approach the ancient Stoics used when dealing with non-Stoics was to show outwardly that they were there for a person and to try and comfort them, but to internally remember the Stoic doctrine of the dichotomy of control, and that what was happening to the other person was not a true Evil, but only an apparent evil. It's also important to note that the Stoic doctrine of the four virtues: wisdom, temperance, courage and justice and the doctrine that virtue is the only true Good, would tend to have the Stoic do the virtuous thing in any situation. If that happens to be comforting a non-Stoic friend, then they would comfort that friend.

ELI5: Why is the Asian last name 'Nguyen' spelled that way when it doesn't even remotely sound like that?

If translating it from a Vietnamese character-set to a Latin character-set and pronouncing it the same way, why is it not just spelled 'W-I-N?'

400-500 years ago, Portuguese and French missionaries arrived in Vietnam. At the time, Vietnam was using a form of Chinese characters as the written language. In order to teach in Vietnamese, the missionaries wrote out the Vietnamese language using the Latin alphabet. From there, the Latin alphabet was used for the written Vietnamese language. As for the pronunciation of Nguyen, this is taken directly from the Vietnamese alphabet. Pronounce the following together: ng, as in si*ng* uy, as in q*ui*ck en, as in -en I adapted that from the Wikipedia entry, which isn't as ELI5-friendly.

Why are train tracks laid on crushed stones/pebbles?

Wouldn't the heavy train vibration move them all around and make the tracks unstable?

In general, the gravel is laid in order to give the tracks a solid foundation. It also serves to help disperse water and to keep the train above sitting water, as well. One of the reasons that trains can be used effectively in certain regions is because the tracks are built using a simple but stable construction. Its very difficult to build roads in certain places due to the ground thawing in the spring and the road cracking or breaking apart because of the unstable foundation. This is why its difficult to build roads in parts of Russia and Alaska. The trains have an advantage, because the gravel is very stable, and much less is required to produce a fairly thin track. While roads are very wide and would require several times the gravel to be stable and to avoid cracking unacceptably. But to answer your question directly, train tracks actually a built with a machine that vibrates the ground and compacts the gravel. This helps guarantee that the tracks will not erode. The rubble is also inspected and any weak areas are fixed fairly easily by an automated machine. This isnt really possible with roads, which require a substantially larger amount of effort to fix defects with the foundation. Since the road itself needs to be torn up, but train tracks can be fixed without even lifting the tracks.

ELI5: How do radio stations or local cable channels come up with names like WBZ, WGBH, or KTZ?

I never understood how they got their names

The identifiers are assigned by the FCC when you are granted your license to broadcast. You can request any 3 letter call sign that is available, but if it is taken you get what you get. The K vs W distinction tells whether you are west (K) or east (W) of the Mississippi river (though their are a few exceptions. There is also N, but that is for military broadcasts.

How fast does something have to move from one point to another for a human to no longer see even the slightest blur in-between?

That depends on how bright the object is, how much contrast it has, how large it is, and so on. There will always be light from that object hitting the eye from every place along its full path, but how much and how detectable that is depends on many parameters, not just the speed. Once the physics is fixed biologists can look at the response of the eye.

ELI5: How do people develop bad eyesight over the years?

Edit: I understand old age, but why do some children as small as 5 years get specs while sometimes people in their 40s dont?

If you mean why do people need reading glasses in middle age and the glasses need to get stronger and stronger as they age more then the answer is as follows ; The lens in your eye gets less flexible as people grow older because layers similar to an onion build up. This lack of flexibility makes focusing on nearby objects more difficult. By shining a bright light at the writing your pupil contracts which increases the focus so you can read small writing in daylight but not indoors.

If we existed on the planet found orbiting Alpha Centauri, would we be able to detect the Sun's planets with our same technology?

Obviously it would be too hot to exist on, I'm just trying to grasp what sorts of planets we are able to discover at this time.

There are two primary methods for detecting planets, the transit technique and the radial velocity technique. The transit technique looks for dimming of the parent star as the planet crosses in front of it. This technique works very well for large planets (e.g. Jupiter) but is sensitive enough to detect even Earth-size planets. However, it requires continuous monitoring of the star (otherwise you'll miss the short-lived transit event), it requires detecting at least 3 transits to be certain that you're seeing the same planet in orbit, and it requires that the alignment between the orbit and the line of sight to the star be within a narrow range. This last requirement is a big problem as it means that only a fraction of a percent of planets in Earth-like orbits would be detectable, all of the others would have orbits which don't pass in front of their parent star relative to our view. On the other hand, the technique works just fine if all you want to do is get a better handle on the statistical probability of planets of various types. So if we were looking at a clone of our own Solar System out in the galaxy we might be able to detect Venus and Earth but the chances of that would be about 1 in 300 or so. The radial velocity technique is a bit different, it looks at the "forward" and "backward" motion of the parent star relative to us over time. If a planet is orbiting the star it will tug on the star a slight amount and force it to move back and forth as the planet orbits around the star. The bigger and closer the planet the larger the amount of movement in the star. Right now we could detect Jupiter around a star, but we'd have to observe the star (not continuously fortunately, just intermittently) for at least an entire orbit: 12 years. Also, if the relative angle of the orbit is nearly perpendicular to our line of sight then the motions of the star will be up/down and left/right instead of back/forward so we won't be able to see them with the radial velocity technique, and with the current level of sensitivity of such instruments that translates into roughly 10-20% of the potential orbital inclinations. **tl;dr** There's about a 90% chance we'd be able to detect Jupiter, though it would take at least a decade of observations, and there's about a 0.3% chance we'd be able to detect Venus or Earth. Although the technology is improving fairly rapidly so what we'll be able to detect in another decade will likely be different.

[Star Trek] How do Inertial Dampeners work?

Newton's first law of motion: An object at rest tends to stay at rest. Inertial dampers "trick" this phenomenon into making the area being dampened move almost as a unit. From a relative perspective, no movement occurs, thus no inertial effect. Relative to the observer, all of space moves around them. If you're asking how it accomplishes this feat... uhm. Gravitons or something.

The Green and Libertarian Parties are a waste, and people who want to advance those causes should work within the Republican and Democratic parties instead.

The Green and Libertarian parties have completely failed to elect any significant officials, not presidents, Senators, governors, major city mayors, or even Congresspeople. They don't get their issues on the agenda in any meaningful way. The mainstream media just ignores them. The US' winner-take-all political system basically makes third parties futile. In many countries in Europe, if you get X% of the vote, you get X% of the seats in parliament, and that system enables alternative parties to have a voice and to have representation. In the US, you have to win your state or your district outright or you get nothing. A party with 10% support in every district nationwide wouldn't get anything for that, and the Greens and Libertarians aren't even close to that. The Christian Right, which represents at most 10% of the country, works within the Republican party, and has unfortunately been very effective at getting its agenda enacted...while libertarians and their separate party have been totally ignored by mainstream Republicans. It seems clear to me which strategy is more effective.

The strength third parties have is threefold: 1. They can bring new issues to the political table. 2. They can draw enough votes away from main parties to affect elections. 3. They can make a big enough deal about certain issues that the main parties pick them up. Historically, parties have had effects on both the political system and the laws it made: The Anti-Masonic party popularized nomination conventions and party platforms, which both the Republican Party and Democratic Party now do. The Prohibition Party got the 18th Amendment passed, prohibiting alcohol, which was a HUGE deal at the time. The Progressive Party helped popularize the ideas of recall, referendum, and initiative in regards to politics. They also brought attention to a lot of tax laws, social insurance, workman's comp, and woman's suffrage. Their candidate (Teddy Roosevelt) also got 27% of the vote in the 1912 election, which is pretty impressive for a third party. The Libertarian and Green parties have raised tons of awareness for their ideas, as well.

ELI5: How does drinking more water help people lose weight faster and increase metabolism?

I've seen the whole "drink 8 glasses of water, you'll lose a ton of weight" article in a ton of places. But how does it exactly help the body burn fat?

Drinking more water can help reduce your food intake. A main reason why people gain weight/maintain a high body weight is because they snack a lot without thinking about it. Drinking water will help curb your appetite and reduce your urge to snack. If you can condition yourself to drink a glass of water instead eating a cookie, you save yourself 100-200 calories. If this happens three times a day, that's a total of around 500 calories. 500 calories is equal to doing a 5km run in 30mins. Eating 500 fewer calories per day will lead to one pound of weight loss per week.

ELI5:Cubesort

How does cubesort work? I was reading about other sorting algorithms when I came across Cubesort, and I can't wrap my head around it. I know how other sorting algorithms such as Quicksort, Radix sort and Mergesort work.

A standard balanced binary search tree (let’s say of numbers) has a root node (avalue at the very top of the tree that should be directly in the middle of our sorted data) with two branches. You compare your key to the root and go from there if it’s higher or lower. You keep comparing until you find your exact key or nothing. Each comparison cuts your search space in half. (O(log(n)) average time for non-ELI5) Cubesort is a two-dimensional array of arrays, so like a grid where each square is a hole you can put your numbers in. Say we use a 4x4 grid, or 16 holes. Your key is used on the x-axis to determine which column we can find it in. Then it is used on the y-axis to find the specific square. Within that slot (remember, grid of holes) is where we will find what we are looking for, if the value exists. In here is also approximately 4 sorted values to look at. Overall, 6 lookups for 64 spots (or O(log(n))) Why is this better than our binary search tree? We don’t need to keep pointers to the various branches all over the place. Some operations are also quicker (O(log(cube-root(n))) instead of O(log(n)) for a less ELI5).

How is it that radiation suits protect people?

Maybe this is TV magic and I don't know what a real suit looks like but it seems like people become immune to radiation when they put on these thin plastic suits. How is it that radiation can be so dangerous and yet so easily dealt with.

The radiation suits you typically see don't block a lot of radiation. To understand their purpose, you first need to know what happens in a nuclear incident or any other situation where radiation exposure is a risk. Essentially, radiation is emitted by unstable particles that decay (the radioactive material). Normally, we like to keep these particles contained, but after, for example, an explosion, these particles can be spread all around or even be airborne for some time after the event. When you enter an affected area unprotected, the amount of radiation you'll take in during your presence is only a small part of the problem. The larger issue comes from particles that end up in your clothes, on your skin or even in your lungs after you breathe them in. These particles cause a continuous exposure to radiation even after you leave the affected area. Especially ingested particles are dangerous, as the radiation emitted by those can directly affect your internal bits, whereas radiation originating outside of your body still has to pass through your skin and muscle tissue (though it can already do damage there). So the main purpose of a radiation suit is to avoid taking too much radioactive material with you.

Do doctors and nurses develop stronger immune systems from spending most of their time working in hospitals? Or do they become sick more often than the general population? Are there any other effects on ones health from working in a hospital setting long term?

It's a combination of things. 1) Vaccinations. Health care workers are always up to date on vaccinations (in theory). 2) Immunity. A lot of diseases (especially some common in kids) are one shot diseases-- you get it and then you're immune. HCWs get these once or twice. 3) Repeated exposure. The more you are exposed to a disease, the more of a response you build to it. It's like getting a booster shot. Whereas someone in the normal population may be exposed to disease x twice in their life, with the second being so long after the first that their immunity is quite weak and they show symptoms, a HCW may be exposed on a monthly basis, and thus strongly fights it off after the first exposure. That said, there are definitely a lot of older docs in fields like Infectious Disease with chronic, tropical diseases and so on. That's life. I have not seen any evidence that the immune system itself becomes stronger, in the sense that it can respond to a new threat better. Rather, it's just that the average HCW is seeing the same diseases over and over, and thus has some degree of immunity to them already.

how do you explain what is "language theory" and automata for someone who has little knowledge about computers?

I've got a book "Introduction to Languages and the Theory of Computation". It mathematically defines a few models of computation without directly discussing actual computers. That seems like a reasonable way to do it.

CMV:Mr. Trump's comments in the video released last week disqualify him on the basis of character to hold the office of the President of the United States

I believe Mr. Trump's comments, seen around the country and world this last weekend, disqualify him - or should - from holding the office of the President. I am a father of two daughters, so not without an emotional bias here. However, the reasons I think this are: 1. The President is a leader. How effective or inclusive a leader can he be having made these comments at 59 years old? 2. The President is a role model. How can we hold this office up as a role model to our children when we have to qualify his comments? I'd appreciate keeping the red herring, Argumento ad hominem out of the responses. I am not in this post espousing a vote for his opponent. Nor do responses of 'other Presidents have done...' qualify as a defense of Trump's comments, though I am probably open to that view being challenged. I'm sincerely interested in a non-partisan, rational discussion. Thank you. Edit: had to run to a doctors appointment and have a couple of job related tasks but will be back as soon as possible. Video source: http://money.cnn.com/2016/10/08/media/donald-trump-video-8-questions/ _____ > *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!*

Can you clarify what you mean by "disqualify"? Are you just saying there's no way you'd ever vote for someone who did this, or are you saying there should be some legal force behind that disqualification, or what?

ELI5: How does the foods industry measure the amount of calories in food? Or is it an estimation? For example, how do we know that a cheeseburger is 900 calories?

**Tl;dr:** For many recipes they look it up in a special tables for common ingredients. For other recipes they do some chemical tests to count fat-proteins-carbohydrates and then calculate using other tables. Calorie is a metric unit of energy (symbol: **cal**). This is the amount of energy you need to raise the temperature of one gram of water by one degree Celsius (in normal conditions). Also, there is an American Calorie^tm, which is bigger, of course (symbol: **Cal**) - it is 1000 standart calories. The number of calories tells you what amount of energy you can get from the food. The method to measure this energy is known as direct calorimetry - you just dry food, burn it in a pure oxygen in a special device in a certain amount of water and measure the temperature change. But this method is not used nowadays on food labels, because humans will take less energy from food than there is (they do not digest fiber*, etc) Now they do some standardized chemical tests (or look in existing tables for common products) to count proteins-fat-carbohydrate-etc quantity - the things we actually take from food. The results are converted into an equivalent energy value. For example one gram of fat will give you 9 kcal = 9000 cal = 9 Cal, alcohol - 7 kcal, proteins - 4 kcal, carbohydrates - 4 kcal. Only fat, ethanol, proteins, carbohydrates, organic acids, polyols and fiber are caloric, so anything else is not counted.

How does a vine searching for and object to climb “know” not to wrap around itself?

I’ve seen a time laps video of a climbing vine and as it circles around searching for something to climb it seems to run into a chute from itself. Upon interacting with itself it simply disengages and continues its search for another object. How does it recognize itself?

There are surface proteins which sense when the vine is touching something. When it does it sets off a signal cascade which causes growth/elongation on the opposite side of the vine. There are a number of processes at work, almost all of which are poorly understood and heavily researched. They also vary between organisms that exhibit the process. If you're interested in diving down the rabbit hole Google "circumnutation" or "helical growth in plants".

[MCU] Did Wakanda ever intend to honor the Sokovia Accords

The Sokovia Accords were, if not the invention of Wakanda, at least heavily lobbied for by Wakanda. At the opening meeting, King T'Chaka made a powerful statement about how their "stolen vibranium" was used to create devastation, and how super powered individuals were a threat to the peace of the world. But the Black Panther, who would clearly be covered by the Accords, operates in foreign nations all the time. One of T'Challa's first acts after the signing of the accords was to sneak into a foreign nation, attack a convoy, and retrieve one of his spies. Justified? Sure. Legal? Hell no. When T'Challa learns that Klaue was in ~~China~~ Korea, he immediately invades that country as well, and in a very public fashion. There is video of the Panther violating the Accords up on YouTube. So my question is: did Wakanda intend to honor the accords, but T'Challa had a change of heart after his father was killed, or were the accords designed by Wakanda to hinder the powered individuals of other nations, and thereby further secure Wakanda's secret advantages?

First, we need to clarify the intent of the Sokovia Accords. The purpose of the Accords was not to regulate superhumans/enhanced individuals, as Clint Barton and Sam Wilson would certainly not be on this list, and arguably neither would Tony Stark or James Rhodes. The purpose of the Accords was to create UN oversight of the Avengers as a specific entity given their history of causing damage and ignoring sovereign borders during their heroics. Ant-Man and Spider-Man, had they not responded to the calls to fight in Germany, would not have been covered under the Accords’ statement that the Avengers would be directed by the UN. The situation related to Bucky Barnes demonstrated the hypocrisy of Wakanda’s position. T’Challa, or any Black Panther, could claim diplomatic immunity in the eyes of the international community due to his status as a member of the Wakandan Royal Family - and that is assuming he was ever caught, which Wakanda’s advanced technology would make difficult. Bucky’s incarceration without trial demonstrated that the UN was taking a hard line on any enhanced individual they found, but T’Challa’s freedom after being apprehended in Budapest shows the preferential treatment he received as a diplomatic officer as well as a superhero. So, long story short, no. The Black Panther, as he is not a member of the Avengers, would not be subordinated to the UN under the Accords, nor would he be held without trial like Bucky due to his station as heir apparent and later King of Wakanda.

ELI5: Existentialism

This question has been asked many times already, so search for more explanations. The basic principle is that "existence precedes essence." This means that you're a blank canvas when you're born. No values. No meaning. No sense of what's beautiful and not, or what's right or wrong. There's no inherent meaning to existence. Your actions and experiences in the world will help you paint your canvas and craft your own essence, *i.e.* your identity. You draw upon these experiences in the world around you. That's why everyone is different because everyone has different experiences. Some people are afraid of this process though. Realizing that there's no inherent meaning and that you have to create your own is scary. That's why some anxious people retreat to the morality outlined by religion or by some other figure. They don't actively create meaning; they just copy it. They aren't subjects; they objectify themselves. This self-objectification and inauthenticity is called bad faith.

Jobs with a purpose with an Economics degree?

I have an internship for an investment bank but I realised I want something with purpose and not that fussed about money. But there doesnt really seem to be jobs that you can do with an economics degree that has a purpose.

Probably not the answer you're looking for... But going and earning enough money that you can afford to donate to charities and volunteer in your free time is a legitimate way to contribute to the world.

I think that the gender wage gap is due to the majority of women's decisions and not discrimination. CMV

I know a lot of liberals are saying that women make 77 cents less than their male counterparts. However, I heard the libertarian's counter point and it's not that they are individually making less, it's just that women work less than men do as a whole. That being said, I want to say that **I am not a misogynist**, I believe women should be treated equally to men in what they do. So if a woman puts in as much hours, does as much work, and have as much education and experience she should be paid the same as a man with the same qualities. It's just that as a whole, women tend to be the care-takers. They also (as a whole) tend to chose lesser paying jobs. Ie; There's more men in engineering sciences. And there's more women in social sciences (Ie; psychology, etc). I believe that women are capable at doing whatever they want, however, women (as a whole) tend to have interests in jobs that pay less than some men do. And that is the reason why there is a gender gap. I believe we have evolved as a society to not discriminate against someone based on gender and race (for the most part at least).

You unduly separate "women's decisions" and "discrimination". A woman's career choices can be affected by the judgments she expects from people. Even a simple "I want to help people" thought can automatically and unconsciously lead to teaching or nursing for a woman and being a doctor for a man. This is because of the lack of stereotype-breaking role models in children's lives. Additionally you fail to ask why all those traditionally female roles are less well-paid. Teachers' pay is set centrally so it's not just the market (although if something is caused by the market that doesn't mean it's not caused by the patriarchy too). Why do we value things women want to do less than we value things men want to do?

How Much Information can the Observable Universe Contain?

If we interpret the observable universe as some kind of data-storage operating at the smallest scale possible, how much information could it theoretically be able to store, assuming that we have infinitely much energy at our disposal to express information? Edit: English

*If* the holographic principle applies, the observable Universe must be dual to a local theory defined on the cosmological horizon. This theory will have entropy scaling with *its* volume, which is the horizon's area, and in fact the maximum information you can have will be 1/4 the horizon area in Planck units (just like for a black hole) - and this will also be the maximum information inside. Just as an order of magnitude calculation: the information will be on the order of (Horizon area/Planck area ) ~ (Hubble radius / Planck length)^2 ~ (Universe age / Planck time)^2 ~ 10^(123) nats ~ 10^(123) bits. Note the information does not scale with the 3D volume, like you'd expect if our Universe was described by a local theory; this is because quantum gravity must be automatically non-local. Practically, if you tried to store bits in, say, a cubic grid, when the grid spacing tries to get around the Planck scale black holes pop up. In general gravity conspires against the storage of this information. Holography provides a possible explanation as our 3D Universe is actually dual a 2D local theory that can only store so much information. Without holography, who knows.

[Star Trek] Why is it so easy yet used so rarely for Starfleet to use surgery to disguise personnel as Klingons or Cardassians or Bajorans or any other species? Shouldn't this be far more widespread in its use?

Though, I also wonder if there's ever any complications from the surgery or the transition back to your normal body.

A) It's superficial, a basic medical scan will instantly be able to tell. B) It's only looks, the person has to be able to talk the talk (both language wise ad cultural wise) and that's not easy. C) Espionage can be considered an act of war, and the Federation is not in the habit of starting wars. That said, all of these things can be overcome, which shows why the technique is sometime used, but it's not used often.

Why does rust not occur on stainless steel?

Lots of metals react with oxygen and moisture to form an oxide. Steel is just iron with a bit of carbon and various other elements to control its exact properties. The iron in steel also reacts with moisture and oxygen (its relatively passive to just oxygen, the moisture helps the reaction along.) Unfortunately iron oxide doesn't stick well to iron because metal expands as it turns in to iron oxide so it flakes off. In addition iron oxide is slightly porous and can adsorb additional moisture, so the rusting process progresses through the metal. Some metals react with oxygen and form a compound which doesn't undergo a significant volume change and doesn't flake off. One such metal is chromium. In addition chromium oxide is pretty stable and is relatively resistant to chemical attack. Stainless steel is steel where a significant quantity of chromium has been added - this chromium reacts rapidly with oxygen in the air and forms an incredibly thin but inert layer on the surface preventing oxidation of the iron. Other alloying elements can be added to further improve the resistance of stainless steel under particular conditions. (High temperature, salt water etc)

What did Stoicism evolve into?

I’m not big into philosophy, but recently I’ve started reading some of the ancient stuff. Among that stuff I’ve taken a particular interest in Stoicism, specifically the writings from Marcus Aurelius. What did these ideas evolve into? Can anyone tell me who are the people that took ideas from Aurelius/Seneca etc. and built off of them? Also, is stoicism still something that’s practiced in the field of philosophy? By that I mean, are there a significant number of academics who refer to themselves as stoics?

Tons of things. cognitive behavioral therapy. Parts of christanity. Neostoicism. There are modern people who claim to be stoics, some even in academia, but the connotations of what it means to be one aren't entirely the same anymore. Philosophy schools in the classical sense aren't really how modern philosophy is done. If you want to learn about how to practice it in modern day there is a godo book called stoicism and the art of happiness that both details its classical beliefs as well as how to make it useful today. And it is written by a professional therapist.

[Star Trek] Can the replicators make decaf tea that actually tastes good?

In TNG episode Lessons, the grad of stellar cartography gets on Captain Picard for drinking Earl Grey at 3 am and said that he shouldn't have stimulants so late. She then replicates "Daren herbal tea number 3," since it is caffeine free but Picard doesn't like it. Why can't they just make a caffeine free Earl Grey? I understand the decaffeination process of real tea destroys any flavor, but why not do a synthetic caffeine that imparts the flavor but not the energy, similar to synthahol that gives a slight buzz that goes away with a surge of adrenaline?

Replicated food most likely work by scanning an already existing food item, and depending on the amount of data stored and complexity of the food, some subtle flavors may also be lost in the digitization process. So if Federation, with its 24th century technology cannot decaffeinate real tea without destroying the flavor, replicator can't do it either. Or they can perfectly mimic the flavor, but without the kick of the caffeine, psychologically it just doesn't taste the same.

ELI5: Why does salt make such a big difference in recipes or adding it to food? Adding a little makes such a big difference. Why?

Edit: Thank you everyone for your responses! I’ve learned so much reading through them and I’m happy to have sparked an engaging discussion!

Salt is its own flavor, but it also acts to enhance other flavors by increasing the “polling rate” of the cells in our tongue which detect flavors. By the same token a lack of salt will make most foods taste bland or one-dimensional. Presumably this is an evolved response to encourage animals to seek out and consume salt, given how critical it is for us.

CMV:Rand Paul's Proposed "Flat Tax" Is The Most Effective Way At Creating a Fair and Effective Tax

-By ensuring everyone has the same tax rate, it keeps it equal and fair for everyone. And technically, the wealthy will still be paying more- 14.5% of 1 million is more than 14.5% of $50,000. -By maintaining a flat tax rate, it incentives Americans to work harder or pursue higher paying jobs that are higher in demand, as they no longer would be burdened with massive taxes in the higher earning brackets. -The standardized deductions still help poor families and individuals survive. By allowing a $15,000 deduction per filer and $5,000 per family member, this helps low income families remain tax free, as they need every dollar they make. The $5,000 per family member also helps support larger families. -Setting a flat 14.5% flat tax on corporate income helps reduce the incentive for corporations to relocate outside of the U.S, as we have the highest corporate tax in the world. This will help the U.S collect more taxes overall, by discouraging the usage of tax loopholes to avoid paying taxes to the U.S, which will help pay for expensive social programs the U.S uses. -Taxing imported products encourages the employment of blue collar workers in America, helping the economy by creating more jobs.

Money is not a linear benefit; Earning 20k a year does not mean you are twice as better off than when you earn 10k a year. Without trying to make up numbers for it, you are _a lot_ better off than just twice. Earning a million a year does not mean you are 50 times better off than earning 20k a year, you are almost an infinite times better off. Money is taxed accordingly. When you earn 200k/year you could lose an additional 10% of your earning without any realistic hardship, if you earn 20k/year losing an additional 10% of your money can mean the difference between getting healthcare or not. Regardless of tax rate, higher earners always take home more money, even if they are 'bumped' to a higher tax rate; you are only taxed for the amount of money you make in the higher bracket, not the total amount. "The US has the highest corporate tax rate" is also not as clearly cut as you make it. It has the highest rate in _theory_, but in practice economics agree that nobody is actually taxed at this rate, and different experts put the real taxation rates anywhere from second in the developed world to below average.

ELI5: What made the world population increase so drastically after 1900?

Excuse me, if this is the wrong sub for this but I’m genuinly confused. According to [this graph](https://flic.kr/p/5T5hkE) I found by accident, the world population barely increased at all between 1300 and 1900. And then it suddenly took off like crazy. What caused this sudden fast increment of the world population?

Three factors contributed the most, but by no means are the only 3 factors. First one being a better understanding of medicine and disease, including the introduction of vaccines. People died less often from preventable disease, especially children, meaning more people made it to adulthood to themselves also breed. Fewer babies dying means both more adults,and more breeders. Second, mechanical farming and chemical farming - that is, artificial fertilizer. Between better fertilizer which improved crop yields, and farm equipment which allowed more to be harvested in less time meaning there was more food for even the new larger population. And third was a combination of the internal combustion engine and the plane. With transportation that made land, air, and sea travel much much faster, it was suddenly much easier to transport all of this food to where the people are. Obviously it's a lot more complicated and this is a really simple explanation

ELI5: How do computers use binary code?

I understand the basic layer of computation: computers work in binary signals (basically electricity/no electricity). But, what do they do with these signals? To what are they translated if so? What is the 'next layer'?

The basic structure of a computer is the transistor. It's basically a switch that when it's turned on, it allows current to flow from the input to the output. The real power of transistors comes when you start wiring them together. Now, the output of one transistor can go to the control of another. That means that when you turn on transistor 1, it turns on transistor 2. By combining multiple transistors in specific ways, you can build simple logic circuits. For example, an AND circuit has two or more inputs and will only turn on if all of the inputs are turned on. An OR circuit will turn on if any of the inputs are turned on. From basic logic gates you can build calculation circuits. These will take numbers (in the form of binary) and add, subtract, multiply or divide them. These are the basic building blocks of performing useful operations on a computer. From there it's just building more and more complex circuits that perform more specialized functions. But, since the inputs and outputs are either on or off, 1 or 0, everything works in binary.

ELI5 Salt Sanitation for a swimming pool

How does salt sanitize the water of a swimming pool?

Chlorine generator in the pump lines creates chlorine via electrolysis. A very small concentration of salt is required to make the process more efficient. People choose salt water pools for the “feel” but also to get around the negatives associated with adding liquid chlorine every day or from using powdered or puck chlorine. Chlorine is broken down by UV rays, so manufacturers add conditioners to the powdered or puck chlorine (cyanuric acid) which acts as a “sun screen” for the chlorine. Unfortunately, the acid builds up over time and reduces ability of the chlorine to do its job. Only way to remove this acid is to replace water, which is not ideal. Salt water pool negatives include damage to surrounding metal fixtures and/or certain types of rock, grout or tile used in the pool.

CMV: Kim Jong-Un probably doesn't like the DPRK regime very much

[**EDIT**]: Although I've handed out a delta already, I'd still appreciate direct challenges to my relatively-unchanged point of view. One of the basic unquestioned assumptions most people seem to have about the North Korean government is that it is a personal paradise for Grand Marshal Kim Jong-Un. I believe that assumption is probably flawed. In fact, I believe that Kim Jong-Un probably dislikes the DPRK regime, and lives a very pained, unfortunate life. By all accounts, Jong-Un was a relatively normal child growing up in Switzerland. He attended Swiss schools, had Swiss playmates and friends, and possibly for a while at least was not even told that he was a Kim family member: those around him were all told he was simply the son of a diplomat. In terms of culture and values, he likely absorbed quite a bit of European sensibilities. In terms of his own outlook on his life growing up, he probably looked forward to a wealthy, private existence, as he was not first in line for succession, and probably had no choice in the matter when the time came. Certainly, as an adult, we can say that what he really wanted to do was hang out with Dennis Rodman and pretty girls on a yacht. Which brings me to the purges. Intelliigence sources in South Korea, the US, and elsewhere agree that Jong-Un's hold on power is not nearly as strong or stable as his father's was. In many ways, this is to be expected any time a young leader comes in to take over from the old king, especially in a more ageist society. Resentments unfold as long-important advisors lose out and shifts in preference occur, leading to internal division and strife. In the DPRK, the signs of this are all around. And the brutality with which Jong-Un's loyalists have carried out the purges is notable, even for North Korea. Generals and other high officials are not simply being executed, but for example strapped to the fronts of cannons, with the ensuing chunks ground into the dirt by tanks. To my view, this paints a picture of someone who wouldn't be innately at home in a society in which three generations of some dirt-poor peasant's family could be executed simply for watching a Hollywood movie. Think about how you'd feel in that situation! Peasants being murdered and brutalized and starved on the daily, just to keep them in line. Anyway, I'd like to hear other perspectives and try to change my view that Kim Jong-Un probably, deep down, feels a lot of guilt and disgust towards the DPRK regime, but has very little power to actually affect outcomes. _____ > *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!*

It's a modern, western viewpoint that values individual life above that of the state. This viewpoint is far less common in the East. I personally think that you're underestimating just how pervasive Nationalism is on the psyche and how deeply a value of "loyalty" can be held and the consequences that brings not just for the victims, but for the user as well. He is absolutely convinced that this is what must be done, lest it would not be done.

ELI5: What are the biological/natural reasons Humans have mental disorders like ADD, ADHD, Bi-Polar, Depression, etc - are there any purposes and/or functions outside a civilized society?

Evolutionary explanations for a human trait *T* need not take the form, "*T* is beneficial because..." Indeed, very often their form is, "*T* persists in the population despite..." What's generally going on there is that some combination of genes that do serve some very useful purposes also happen to have a side-effect that is not at all useful, but the benefits of the useful things outweigh the drawbacks of the nonuseful one, at least enough to cause that combination of genes to continue being handed down to successive generations of offspring.

ELI5: How do large and complex projects - e.g. the James Webb Space Telescope (JWST) - keep pace with, and accommodate, technological changes over extended design and build periods?

For example, JWST's control systems originally designed in 1992 would, I'm sure, look very different to control systems designed today. Will they have been updated multiple times along the way?

Systems might be updated during multiple rounds of the design process, but at some point the technology is locked in, which is essentially the same as a freeze in software engineering. At that point, no further changes or updates are made even if new technology becomes available unless it's to fix some problem that comes up in testing. Things that go into space are very expensive and once they're up there, there's no way to swap parts or change or fix things, so you want something that as reliable as possible, which pretty much always means something that's been around longer and has time to have been extensively tested and have had all the bugs worked out. Reliability is what's most important, not what's newest.

CMV: You can be racist to white people

Recently, my elementary school going brothers were learning about racism and anti-racism in their schools. I asked the question - can you be racist towards white people? My youngest brother (age 11), thought about it and said no. My other younger brother (age 15) said yes. Naturally, this led to a good discussion and we all agreed that on principle you can be racist towards white people. We spoke about how marginalization exists beyond skin color - such as class and socioeconomic status. We talked about how imitating “rednecks”, “hillbillies”, “white trash” is similar to imitating Chinese people or Indian people. Or saying - “no whites allowed” in your restaurant is at the same level as saying “no Blacks” allowed. Which is why in my view - you can be racist towards white people. I’m open to all perspectives, and want to see my viewpoint can be changed. I understand from grad school that people in power can always go back to their comfort of power and privilege and that allows any racist attitude to simply rub off their backs - but this is a viewpoint that I believe to be contrary to human experience. For context - I am brown, South Asian.

Here are some tips that may save you a lot of time: ​ 1. This question is incredibly common in CMV. If you want some insightful answers, just search "racist to white people" in the delta search. 2. The long QAs almost inevitably end up being a definition debate. The definition debate takes the following form: Person A: Defines "racism" as prejudice + power as many people do, and then argues that the places where white people hold the power are places you can't be racist to white people. Person B. Defines "racism" as prejudice based on race only, as many people do, and then argues you CAN be racist to white people.

How does space have a temperature if it's just vacuum?

Remember that "temperature" is a pretty handwavey concept. We can't measure temperature directly. We can measure *changes* in temperature, by seeing how something metallic expands or contracts over time for example. Or we can measure the radiation coming off an object and make a guess as to its temperature based on how well or poorly that object approximates a perfect heat emitter. And so on. But to say that something *has a temperature* is always going to be slightly squidgy. In the case of outer space, when we say that it has a temperature and that its temperature is about three degrees absolute, what we mean is that a perfect black body in that environment will settle down to thermal equilibrium at that temperature. That temperature corresponds to the point where the object is emitting the same amount of thermal energy via radiation that it absorbs from its environment.

Our only "real" purpose is to survive, reproduce, and our-compete others for scarce resources. Ideals are fine, but we shouldn't let them obscure this underlying reality. CMV.

We were taught to play nice as kids, with the golden rule and whatnot. As an adult, if your eyes are open at all to what's going on, you're likely to be disturbed by just how shitty people are to each other. Why all the killing, raping, exploiting, destroying the environment? On a less extreme level, in your workplace you see people trying to get ahead by any means necessary, even if it means pushing others under the bus. People are always trying to one up each other to gain social status, and reap the rewards that come with it (including better selection of mates etc). We let ourselves be disturbed by this: why can't everyone just play nice? But we humans are just animals after all, we are a product of evolution. While we have some freedom to try to act more highly evolved, we should acknowledge our roots, as ape like creatures, and before that, rodents, fish, and ultimately microorganisms. We aren't special. Life for all of these organism s is a daily struggle to survive and outdo your competition. Its the same for us, only in a less obvious way, because civilization tames and prevents our most outright aggression. If you acknowledge that life is fundamentally about survival and competition, you might find reality less disturbing. Also, you might take steps to make yourself more competitive, instead of complaining how life is so unfair. The danger of this, of course, is if we forget morality entirely and just all act like selfish brutes.

Purpose? We have an intrinsic purpose? News to me. Who assigned this purpose? >we should acknowledge our roots, as ape like creatures Yeah! Those stupid plants trying to photosynthesize. Don't they know that they come from one celled organisms, incapable of producing sustenance from the sun?

ELI5: How/why do windows and doors not cave in under the pressure/weight of the water from a flood?

[Like here](http://media.gettyimages.com/photos/woman-cleans-the-inside-window-of-her-wine-bar-as-the-floodwaters-picture-id502688966)

Because often by the time the flood waters reach high enough to put sufficient pressure on the door or window, water has leaked into the house from other gaps, like the walls, subfloor, etc that the water pressure on both sides is equal. In that picture, that window might be thicker/stronger, and able to better resist the pressure.

ELI5: How can astronomers tell how 'old' light is? In other words, how can they tell if they are looking at an object 10 light years away or 1009 light years?

for close objects you can use parallax, which is the same way you get depth perception from binocular vision. Only with stars, you take images about six months apart, so the distance between your "eyes" is about 2AU. Basically, how much do the foreground stars move in relation to the background stars. For more distant objects you can either estimate based on how fast the object is moving away from us(redshift), or you can calculate based on how how much light reaches us vs how much light an object of that type is supposed to make(standard candle). Once you know how far away something is, you know how long light took to get from there to here, because the speed of light is known.

Is deductive logic a special case of inductive logic, or is inductive logic a special case of deductive logic? (Or is this entire disjunction false?)

I was reflecting on inductive vs. deductive logic, and I feel like I'm hitting an infinite regress or something and my brain is short-circuiting. **In favor of deductive being a special case of inductive:** * Deductive logic is just inductive logic where the probabilities of the premises = 1. **In favor of inductive being a special case of deductive:** * Probable premises (i.e., premises with probability x, where 0 < x < 1) necessarily/certainly follow probably. That is, the inductive premises are nested in certainty—namely, being *certainly probable.* I think it's similar to having something be necessarily possible. Thanks. Maybe I'm just being silly.

Inductive and deductive arguments are distinct because each is characterized by a distinct relationship between the premises and the conclusion. The premises of a deductive argument *purportedly* entail the conclusion (if the premises are true, then the conclusion must be true). The premises of an inductive argument *purportedly* support the conclusion, but do not entail the conclusion. Whether the premises are certainly true or probably true is irrelevant to the form of the argument, and it is the form of the argument that makes inductive and deductive arguments distinct. A deductive argument in which the premises do in fact entail the conclusion is valid, and if the premises are true, then that argument is sound. An inductive argument in which the premises do in fact support the conclusion is considered strong (depending on how well-supported), and if the premises are considered true then it is also considered cogent.

CMV: Why is someone an asshole if they want to apologize to someone they bullied in the past? I don't see the logic here.

I'm specifically referencing this recent post on /r/AmItheAsshole: https://np.reddit.com/r/AmItheAsshole/comments/d7gwgd/wibta_if_i_reached_out_to_a_girl_i_used_to_bully/ ...however, I've seen this same view shared by numerous people on Reddit. A lot of people seem to be calling OP an asshole for wanting to apologize to someone they bullied in the past, and I just don't see that logic. OP did something wrong, and she wants to apologize. How does that make her an asshole? One common thing I've seen is people saying she just wants to make herself feel better, but I don't see why that matters, especially since that's just how people feel about it. No indication from OP gives off that vibe, in my opinion. It seems like she's genuinely interested in apologizing to the person she wronged. But people still call her the asshole in that situation. Was she an asshole for bullying in the first place? Absolutely. But what's so wrong in wanting to apologize? I've always been raised in a way that if I do something wrong, I apologize and try to correct it. But now suddenly when someone like the OP of that post (and many other OP's of other posts I've seen in the past) wants to apologize, it makes them assholes? I'm just not seeing the logic there, but I really want to. Can someone please try to change my view here?

It depends on the situation. Generally its some person wants to apologize because they feel terrible about what they did and they want to feel better about it by apologizing. That has nothing to do with the person being wronged, they just want to make themselves feel better. The apology gives no closure to the victim, it does nothing for them. You can read the next to last sentence of the persons post to see why they want to apologize, and you can read the sentence before that about the victims life now to see why she should leave her alone.

[DC] Are the New Gods in each universe aware that they’re just a “lesser” piece of their real version?

As I understand it, new gods “refract” through the multiverse like light does through a crystal. Their versions in each singular universe are just different wavelengths of their real, multiversal selves that exist in the sphere of the gods. So, are the versions in these universes aware that they’re not actually the real thing? Do they share a consciousness on any level? Or are they just limited to their histories in their own universes?

So, basically, they're aware they're technically connected, but they're functionally independent. Like how your body is technically trillions of cells rather then one organism. There *are* situations where that distinction is relevant...but they're rare. Typically, outside of a doctor's office, you can treat everyone around you as one being. Same here, just in reverse. Just like you are all intents and purposes one creature, the guy shooting an omega sanction at you is to all intents and purposes the real Darksied. The New Gods are *aware* of the technicalities of that statement. but they can typically ignore them. Each New God is functionally a separate being and continue to think of themselves as one except when the theoretical details of their existence become relevant.

ELI5: How can someone take a picture of a solar system 50 million light years away, but not a coin sized rock on the surface of the moon.

I recently saw a photo somebody posted of a galaxy 50 million light years away. I have always wondered, why doesn’t he point it at the moon or even a planet 10 light years away and see the surface up close? We might see water or certain organisms. I have yet to see a picture like that in my lifetime. Thanks in advance for the answer.

a) the star is actively sending out light, it is shining while the surface of a planet only reflects a tiny bit of light back out b) the star is several million times larger than a rock on a planet, so even if the planet is something "close" like one in Alpha Centauri, the size/distance ratio still favors the star. c) planets have atmospheres. hard to see through clouds from above (which is part of the reason we send those rovers to mars, to land there and take pics from there)

What is the significant of Nietzsche and Proust in the movie "Little Miss Sunshine"?

There is probably more to it but part of the reason Nietzsche is brought up a lot is because it is the kind of stuff covered in high school or intro courses that people really first start thinking about that kind of stuff. It is suppose to show that he is being "emo" or sort of a typical secluded teenager who hates the world kind of character. There might be more to it than that but it is primarily character building, regardless of his interpretation being correct.

I believe that prostitutes, porn stars, and other jobs which directly relate to selling the body SHOULD be treated as equals in society. CMV.

I hold my view that a porn star, a prostitute, someone who designs sex toys, etc, all people of this manner (clarity: Someone who sells their body or spends their career directly in this business (e.g. a prostitute and 'procurer' (pimp) respectively)) should be treated just like any other job where it is legal, because I believe that the selling of their body is just equivalent to someone selling their mind or any other skill. A scientist is paid merely for his mental work. A footballer is primarily and sometimes only paid for their physical skill in their respective field. So why can't a porn star be treated to at least a relative level of societal respect for their sexual skill? Some of them work extremely hard at their jobs, and gain extreme prowess in sexual areas. E.G.: A prostitute is someone who you don't trust, don't go near (unless for the obvious), and someone who is generally looked upon as inferior and menial in society. The same applies for some porn stars: in Boogie Nights, a good example is when a retired porn star attempts to start a business, but is unable to because nobody will give loans with his history as 'a pornographer.' Nothing illegal, no robberies, just pornography. While I doubt today is not as strict as the world back then, some businesses are still this judgmental. Please Reddit, CMV.

Every profession has a certain image, not just sexworkers. Plumbers aren't as respected as brain surgeons. The reasons sexworkers are on the lower end of this spectrum are, for example, that they didn't have to get any degree and that they often have connections to criminality.

Why are absorption lines not lines?

It seems that in every absorption spectrum you come across, you come across many as a physics undergrad, the spectral absorption 'lines' are not lines at all but sharp curves. What I mean by this is that they are finitely wide- (for example the solar spectrum - http://upload.wikimedia.org/wikipedia/commons/4/4c/Solar_Spectrum.png) - whilst the energy required to promote an electron in an atom is supposed to be only one exact value. Which would make you think that the absorption should be at one wavelength and have no uncertainty in it, ie infinitesimal thickness to the absorption line. Can anyone explain why this would be the case? I have been playing around with the idea that some dopler shift may be the involved but I can't resolve it. HELP ME SCIENCE!

There are many different sources of line broadening. The must fundamental limit is lifetime broadening: since an atom does not remain arbitrarily long in an excited state, the uncertainty principle, or if you prefer the Fourier relationship, guarantees that the line will have a finite width. Otherwise, any interaction may cause an increase in line width of the order of the transition frequency associated with the interaction. Examples for this are dipolar broadening, unresolved fine structure (Lamb shift and such), hyperfine structure, etc. You are also correct in that Doppler broadening can be important. Very stable transitions are actually hard to get and a lot of effort is expended into having as sharp as possible transitions for use in atomic clocks or laser systems. The eigenvalues of a composite quantum system are not "supposed to be" a single exact frequency. That is an approximation that is often made, but it's not how you should generally think about things.

Collaboration problems

I have been collaborating with a colleague from another department for a little over a year, and now that we are in the writing/publishing stage of the study, there are some issues popping up that I could really use advice on... The biggest problem is that I am learning that my collaborator is somewhat intellectually lazy. This person is very enthusiastic (to say the least) about churning out as many papers as possible, without giving a lot of thought to the intellectual/academic merit of these papers. This often results in them producing work that (both I and reviewers believe) is sloppy, poorly researched, and often poorly written. I am left doing some much editing on each piece, that I might as well just write these papers on my own. The second (related) issue came up today, when this person sent me a paper they had been working on (on which they are first author and I am second). As I was reading the literature review this person "wrote", I realized that it was basically lifted word-for-word from multiple documents *I* wrote in the past...Basically my collaborator/co-author did not do any additional research or writing on his/her own. This person copied and pasted my paragraphs (from multiple sources) and sort of patched them together. In principle, I have no problem with this, because we are both authors on the paper and the ideas are similar. However, I also feel thrown off, because they sent me the paper saying they had been working on the literature review for weeks. It also raises some questions in my mind about order of authorship for this particular manuscript. I can't help but feel like I'm sort of being taken advantage of in a weird way. I don't know how to approach this person about their lack of academic rigor without ruining this relationship. Not only do we have several ongoing project together, but we also share grant money to collect more data. Also, there are some benefits to this collaboration, as this person has a lot of contacts in the field and has made much of our data collection efforts possible. ANY advice would be greatly appreciated..

best advice, imo, is to take this as an opportunity to improve your soft skills and learn from experience. I've been in a similar situation, and it is never easy to deal with it. The best outcome here is compromise, that almost by definition, probably none of you will particularly enjoy. You'll try to nudge him into doing more serious work, he'll probably resist some and you'll eventually have to pick up the slack, and decide if the end result is acceptable by your own standards. I definitely do not recommend sharing your opinion about the quality of his previous work, unless you are not at all interested in collaborating with him ever. If anything, learn your lesson, and run a background check before you decide to collaborate with anyone.

[Man In The High Castle] Would the Reich have implemented rules straight away after they defeated the US. Or would there have been a grace period of letting the former Americans adjust to the Nazi way of life?.

It all depends on the conditions of the victory. Was it a calculated surrender by the US to save millions of lives before they laid waste to most of the continental united states? Or were there nazi troops in Kansas and Colorado and suddenly we were not at war one day anymore because we just happened to no longer have an army, because they were wiped out to the last man? In the former yea even a war tired populace wouldnt just like a light switch just take it. But with the latter example huge amounts of the nazi army is already on the ground and is there to police their way of life into them and kill any one who gives them problems.

reading guide to Carnap and Quine?

Looking for reading recommendations for Carnap and Quine. What are the best works (primary and secondary) for understanding their disagreements? In what order should I tackle these guys? Looking to understand logical positivism at its strongest and what is supposed to have contributed to its "extinction". I'm generally familiar with the big picture ideas of LP, but I want to get nitty gritty.

The short, classic papers are Carnap's *Empiricism, Semantic, and Ontology* and Quine's *Two Dogmas of Empiricism*. For a more extensive developments of their positions in general, Carnap's *Logical Construction of the World* and Quine's *Word and Object*. Neurath is the key figure mediating between them, and the crucial writings are mostly found in his *Philosophical Papers*. Uebel's *Overcoming Logical Positivism from Within* is an excellent secondary source covering the key developments.

Have any philosophers talked about turning human weakness into strength?

Nietzsche is the obvious one of course, turning suffering into strength. Or more accurately maybe strength is born of suffering in his view But as somebody who has mostly read Schopenhauer, Pascal, and Buddhist thought, I think they make pretty strong cases about how the myriad imperfections in human existence makes it pretty damn miserable. We never stop desiring, we never stop fearing, we're hounded all our lives by the endless changes in ourselves and the world. But I know at least from just popular culture and media that some people interpret this as a positive. Man's restlessness drives us to great things and without desire or fear, we might have done nothing great at all. I would assume much smarter people have written on it though and was curious if anyone here could suggest some? Thank you in advance.

Judith Butler writes a lot about turning vulnerability and precarity into power by using them as a means of identifying with other vulnerable and precarious people to create mass movements. The argument is set out in her book, Precarious Life, and explored in practice in her edited volume, Vulnerability in Resistance.

[Star Wars] How was a 14 year old Amidala elected Queen of Naboo? What did her political campaign look like? What campaign promises did she make, and why did the people of Naboo think that she was capable of accomplishing them?

The people of Naboo have the cultural notion that children are "pure" and unbiased, and therefore can make good decisions if presented all the information. That is why their Kings and Queens (which are just the terms for their head of state and is an elected position with strict term limits) are chosen from their young. Now that does not mean they are not without guidence. The children who are able to run for election have almost all universally have been trained from a young age in diplomatic schooling programs that teach them what is required of a politician, the minutiae of political dealings, diplomatic practices, and other vital information and training for a political life. They also have a council of seasoned and experienced councilors and cabinet members who have spent years in the civil service, some who have may even have served as King or Queen in their youth. They are able to provide the needed experience and advice to the head of state an can guide them in the decision making policies.

I've read ~91% of the books on the /r/Economics reading list, how much do I know compared to the average undergrad?

I've read almost all of the books on the /r/economics reading list (64 of 70). I've also read and studied Mankiw's Principles of Economics. Compared to a reasonably smart and accomplished undergrad at a state school, how much do I know and have yet to learn at the undergrad level? I ask because in the long run, I'm interested in maybe getting a masters or maybe even pursuing a doctorate (if I can get into a top 40 school) in Economics.

Math skills and familiarity with the intermediate micro/macro/metrics coursework are far more important for grad school admissions than the pop economics books on that reading list. \-Former PhD candidate

Can anyone explain how bone healing works after an amputation?

I am doing a dissertation on the survival time post amputation of some sailors from 18th century Plymouth. I would like an explanation to how bone healing works after great scale trauma such as amputations.

Look up bone wax and bone hemostasis by means of tamponade. Note that it does not cause normal clotting. Bone can bleed very profusely and cannot be cauterised or compressed like tissue. Sailors softened a mixture of beeswax and salicylic in hot water (which also steralised it) and smeared it to block the bleeding edge of the bone (Its the marrow that hat bleeds). Ive not heard of it before 1890, but its basically still how its done, except they use new soluble putties.

ELI5: How do drugs like meth and crack change someone's appearance?

Thank you all for your contribution! I will get to upvoting all of you... tomorrow.

Constriction of blood vessels decreases the amount of blood that reaches parts of the body, and parts that rely on the smallest vessels may not receive enough blood to remain healthy. Skin and the face are two examples, and the mouth is a special case because other regulating systems are also compromised, like saliva. Smoking complicates mouth problems, and injection further compromises the already-suffering skin with wounds, which the body struggles to heal. Not sure about hair, eyes, and nails and stuff.

ELI5: What is economies of scale?

When you are producing a product there are fixed costs (something you pay once regardless of how many units you produce) and variable costs (costs per unit). Since fixed costs are fixed then their cost is divided across the total number of units produced, which means the total cost (fixed+variable) for a unit decreases with the number of units. So the more of something you make, the cheaper it is to make it (usually). For example, doing R&D to make a widget is something you have to pay whether you want to make 1 widget or 1 million widgets. If it costs you $100,000 to design a widget, and $5 to produce the widget, if you make 10,000 of them then your cost per widget is $15 ( (10,000 * $5 + $100,000) / 10,000), but if you make 100,000 widgets your cost per unit drops to $6.

ELI5: What exactly was Prussia vs. Germany? What exactly was Bavaria in relation to both? I'm trying to get a handle but it's very convoluted with monarchies that covered different countries, and independent states that aren't really independent, but also had its own monarchy?

Germany is a modern nation state that was created in 1871. It unified several of the German states, two of states included Prussia and Bavaria. In the middle ages, there was realm called the Holy Roman Empire. This empire has origins in the empire that Charlemagne created in France, the Benelux countries, and western Germany. However the HRE shifted more towards the Germany states, as well as other central European powers. Within the Holy Roman Empire was the kingdom of Germany, and many of the early HRE emperors were Germans (such as the Ottonians). In the early modern era, the Hapsburg family became the Holy Roman Emperors. This family comes what from what is now Austria. That is why Austria became the leading nation withing the HRE in its later history. During the Napoleonic Wars, the HRE collapsed and was essentially replaced by the Austrian Empire. Starting in the middle ages, the Hohenzollern family became powerful in North-East part of the HRE, which is Prussia. They basically replaced the rule of the Teutonic Order. First as a duchy then as a kingdom, the Prussian country grew real powerful real fast, and essentially became a competing power to the Hapsburgs rulers of the HRE. In the late 19th century, it was the Prussian that really pushed for German unification and were the driving force in that. The German Emperors were Hohenzollerns. I am not too familiar with the history of Bavaria, but they were a duchy and then kingdom that was a part of the HRE. They were mostly ruled by the Wittelsbach family. They joined the Prussians during the push to unify Germany.

What is the significance of the third law of thermodynamics?

I found on the internet that the third law is defined as: “The entropy of a perfect crystal is zero when the temperature of the crystal is equal to absolute zero”. I know very little about physics, so if somebody could explain, in layman terms, what this means and why it is significant that would be great.

There are multiple ways to state the third law (refer to the Wiki article on the third law to see them). But the important consequence of the third law is that the heat capacity of any system goes to zero as T approaches 0 K. This is what prevents any system from ever being cooled to absolute zero in practice.

ELI5: if honey is antimicrobial how is it also a botulism risk for infants?

Am I just misunderstanding what people mean when they say it has anti microbial properties? Like, it’s hostile to most things but not all? I have no intention of feeding an infant honey, I was just wondering.

Many bacteria can form spores that can't multiply but are also largely immune to the world around them. Honey doesn't have enough water for bacteria to multiply so it doesn't go bad but still has some limited number of bacteria especially in spore form. What makes you sick from spoiled food is generally the toxic bacteria waste not the bacteria In adults this isn't a problem. Botulism spores enter, reach your stomach, bloom, and are promptly killed by the acidic hellscape they tried to call home In young children their digestive tract isn't hostile yet so the spores are eaten, bloom, and then multiply and begin releasing botulinum toxin giving the child botulism

Should Marginal Utility be equal across individuals?

I think the answers definitely No, but would like someone to confirm it for me and also if possible give some reasons to support why not? This is for a Presentation of mine in my Economics Class.

Ask yourself: what is the equilibrium condition in the market relating prices to marginal utility? Review Varian, *Intermediate Microeconomics,* chapter 5. Does that equilibrium condition hold for all individuals? Don't want to give away the whole answer to what is essentially a homework problem.

ELI5: Why does spinning around in a circle make us dizzy?

IIRC, balance is sensed in the inner ear by a pocket of fluid. When you spin in a circle, the fluid starts to spin too (think whirlpool); when you stop spinning, the fluid doesn't. Ergo, although you've stopped, it continues to feel like you're spinning.

ELI5: why are there weight limits on suitcases but not the people on the plane?

It's worth noting there may be weight limits depending on the size of the plane. A large airliner doesn't really matter, but a small passenger plane has to know the weight of the passengers and make sure they're evenly distributed around the plane. You can't have a 500lb person in the right side and a 30lb person in the left, the balance of the plane will be too far off.

[ELI5] The situation in Fukushima, nuclear meltdown and radiation.

Just read an article about Fukushima in Japan and the scientists are saying "all of humanity will be threatened for thousands of years’ if the Fukushima unit 4 pool is not kept cool." What does this mean?

To understand this you have to understand what is going on in a reactor. So let's start there: Everything is made up of atoms. An atom has 3 distinct components called protons, neutrons and electrons. The exact combination of these three things determine how an atom behaves and what element it is known as. Some combinations are unstable and will break down into smaller parts and in doing so release energy and the unused parts. This is nuclear fission. The energy released is of various types and some of it is what we feel as heat. We can use this heat to make steam from water and drive turbines which then generate electricity. This rate of decay is normally fairly slow (for more on this, look up 'half life'), but there is a way in which it speeds up. In some elements (a specific combination of protons, neutrons and electrons remember), the unused parts of a broken down, or decayed, atom trigger other atoms to break down. This is a chain reaction, as one atom sets off another. If uncontrolled, you have a reaction that keeps growing and growing and providing more and more energy, also known as an explosion. If you want to generate power, this is a very bad thing indeed! So what is done is another material is added that will absorb the unwanted parts of the broken down atoms and stop them from triggering another atom to decay, these are the control rods. This gives us a nuclear fission reaction which we can control and use to generate heat, which creates steam, which creates electricity. Now the situation at Fukushima: Fuskushima is a nuclear power station, which means it produces electricity using the method outlined above. In a large earthquake, the reactors of the nuclear power station were shut down by adding more of the control rods to absorb the unwanted parts of the reaction. This stops the chain reaction in part, but not entirely. The system is still very hot and radioactive (the breaking down and releasing of energy is still going on). Radiation being released into the environment is a very bad thing indeed, as it is very destructive and kills lots of things. The first thing to remember is that the reactor doesn't go from hot to cold in a few hours, it takes much longer than that. Also, it has to be cooled to stop the heat building up and destroying the part that shields the reactor and stops the radiation getting out. So long as this heat is managed, there will be no meltdown. This means that, under current conditions, Fukushima cannot have a meltdown and is pretty much not going to. The problem with Fukushima is that they are using water to cool the reactor (it's on the sea for a good reason!), but in the process of cooling the reactor the water becomes radioactive. Putting radioactive water back into the sea then affects the marine life and the food web in general. However, the amount of water required to cool the reactor is so much that storing it is proving impossible, not to mention the water flowing through the ground is also turning radioactive. The end result is that radioactive materials are being released into the world, which is a bad thing. TLDR: Nuclear fission is the breaking down of atoms into smaller atoms, bits of atoms, and energy. This energy is used to heat water to drive steam turbines to make electricity. The bits of atoms collide with other atoms, making them decay and forming a chain reaction. Fukushima is a power station that uses this to generate power, and was damaged in an earthquake. The chain reaction was mainly stopped by using control rods, though the reactor is still very hot. Water is being used to cool the reactor stopping it from melting down, but is being turned radioactive in the process. Other water flowing through the site is also becoming radioactive. This radioactive water is being deliberately and undeliberately released into the sea, where it will cause problems over the years.

Can light waves interfere with sound waves? (or vice versa)

Yes. For example, a sound wave can cause a spatial variation in the refractive index of a material, which will cause light to change its path. This is called the acousto-optic effect. You can use a laser to heat things up so fast that they emit sound, and this is called the photo-acoustic effect. A basic interference pattern of sound waves and light waves won't exist in normal circumstances though.

ELI5: How does IQ test actually work?

it compares how well you do on a specific set of puzzles compared to the average of people the same age as you. these tests are constantly re-calibrated, for example kids these days are pretty good at some of those compared to kids a hundred years ago, so using the old tests kids would now score something like 110 or 120 on average. a score >100 means you're better at these puzzles than the average person from your generation, a score <100 means you're worse than them. but since the puzzles are often pretty similar between tests, you can actually practice this kind of sequence completion and increase your score this way

What does "subject" mean in Continental Philosophy?

The term "subject" or "subjectivity" seems to be fairly common in 20th-century Continental Philosophy, but I find it pretty confusing. What, exactly, is a "subject"? Here are a few examples of specific uses of "subject" or "subjectivity" that I am confused by and was hoping to have cleared up. Example 1: when [Althusser writes](https://www.marxists.org/reference/archive/althusser/1970/ideology.htm) "there is no ideology except by the subject and for the subject," what is the "subject" he is referring to? Example 2: the [SEP article on Marcuse](https://plato.stanford.edu/entries/marcuse/#PhiAntRadSub) contains the following sentence: "radical subjectivity refers to the development of a form of self-consciousness that finds present social and economic conditions intolerable." What does "subjectivity" mean in this context?

In general, a subject is the human subject. An actor with agency and a conscious experience. Subjectivity is the prerequisite quality that you need to possess to be a subject. Some specifics: Example 1: To Althusser, specifically, there is also a distinction when compared to an individual: a subject is a subject in as much as they are also subjects acting in and subjected to the world and society, interpellated from individuals through ideological processes. Ideology is generated by us and for us, subjects. Example 2: Radical subjectivity, here, looks towards developing a mode of being another kind of subject. Through this development, one might better understand to seek freedom from the socioeconomic chains that (per Marcuse) bind them. You could implant something like a Marxist false consciousness inside a subjectivity as an example of that which would prevent one from understanding the basic coordinates of their own unfreedom. Critical theory might look at how to develop a sense of being a person that sees through this.

In a rehabilitative justice system, what should we do about people who cannot be rehabilitated?

I consider myself a strong proponent of rehabilitation – strongly inspired by the success that Finland for example has had with their prisons. [Viral clip here](https://www.youtube.com/watch?v=l554kV12Wuo) [And a similar video on Norway’s prisons](https://www.youtube.com/watch?v=zNpehw-Yjvs) Today people are locked up in what I essentially believe to be degrading, violent, and abusive human storage units, and while I may not be comfortable at the thought of these facilities existing, I can’t think of any reasonable non-violent alternative for people who are psychopaths, sociopaths, or the criminally insane(I'm aware that this last one is very broad). So what do we do about these groups in such – or a similar – system? Thank you.

There are three basic justifications for prisons: rehabilitation (yay!), retribution, and keeping society/the inmate safe. You can combine these three justifications in your theory of just imprisonment. Presumably, keeping society safe is a reasonable justification for keeping an inmate who can't be rehabilitated locked up. Any theory that's *purely* any one of the options is probably going to run into serious problems for the kind of reason you've highlighted here.

In what situations are Tariffs good for an economy?

I've been reading Tim Harford's The Undercover economist and he mentioned that tariffs are almost always bad for an economy. I am assuming there are situations in which they could be beneficial though - say the Govt. is trying to help a sector grow due to possible future gains. Am I wrong? Or have I missed something?

There are two "textbook" situations where tariffs can benefit an economy: 1. If a country has a large domestic market for an imported good and the production technology for that good features increasing returns to scale (per-unit costs decrease as a firm gets larger), an import tariff could make it profitable for domestic start-ups to enter the market and grow to a level where per-unit costs are comparable to existing international firms, and would therefore be able to compete in the global market once the tariffs are lifted. The short run losses caused by the tariffs would be offset by the efficiency gains from the new domestic industry once the tariffs are lifted. Note that there is no aggregate benefit to the country if the tariffs are not eventually eliminated. Some models suggest that this outcome could also be accomplished more efficiently using quotas rather than tariffs. 2. If a country is the dominant importer of a particular good and that good is supplied inelastically (the quantity produced is not sensitive to the price), then a small tariff might increase aggregate welfare. The increase in domestic price that results from the tariff is partially offset by the decrease in the global price of the product driven by the decrease in demand (due to the tariff). This offset, combined with the government revenue from the tariff itself, could be large enough to entirely offset the "deadweight loss" associated with the tariff. Note that the tariff would have to be small and the country would need to have considerable market power for this to work. Neither scenario is likely to occur with any regularity in the real world.

ELI5: Why Do We Get Dark Circles Under Our Eyes

I've been told its because of lack of sleep, but that seems like a falsity. What's the real reason?

First we need to understand the *physics* before getting to the biological reason for it. The reason the area under your eyes are prone to **darkening** (be it dark circles or a punch to the face) is the skin under your eyes being thinner(0.5mm) compared to the rest of your body(average 2mm). Add to that the high density of blood vessels and capillaries in that region. And you have light reflecting off the back of the blood vessels sitting under that patch of incredibly thin skin, giving it a darkish appearance. Now the biological reasons for the darkness increasing are not one but many; with genetics playing the more important role than others. Some of the causes are: 1. *Old age* : As people age their skin loses elasticity and the ability to regenerate and as a result becomes thinner. This is the reason older people predominantly have very prominent dark circles. 2. Preorbital Hyperpigmentation is a genetic condition in which more melanin is produced in the skin below your eyes. 3. Another curable illness causes damaged blood vessels below your eyes to leak small amounts of blood. 4. **Fatigue**: Yes fatigue can indeed cause dark circles but they are by no means the predominant factor. When the body is tired, production of the chemical **cortisol** is dramatically increased to help give you the energy you need to stay awake. Among many other things, cortisol actually increases the volume of the blood in your body, which causes the blood vessels (including the ones below your eyes) to engorge to accommodate it. tl;dr: Yes fatigue can cause dark circles but genetics and ageing are the most likely cause of developing them. edit: improved the answer a little bit.

[Star Wars] Does the Jedi Order have a "Bible" or equivalent religious text?

The Jedi have a holocrons, which contain the wisdom and lessons of past Jedi Masters. There is no specific 'Jedi bible', and instead they follow an mostly oral tradition. There are Jedi texts and scrolls, but no central unified document. Presumably this is due to the changing nature of both the force, and the Jedi order itself.

ELI5: What is the most common cause of big projects over running on their estimated budget? For example, I recently learned that the HS2 train line in the UK will be nearly £75bn over the estimated budget! How was the estimate so wrong?

When a job is bid and an estimate is given, that’s all it is, it is an estimate on material and labor and some wiggle room for profit and mishaps, not much though. The bigger the job the more problems can arise and bigger the problems can be, for example, you can look at a topographical map to plot the train line but maybe the map hasn’t been updated in awhile so you throw a good number at it and turns out someone threw a house right where you want your line, or what is more than likely the case as it happens most often here in the US, they plan on buying the owned property along where they want the line and the owners of said property refuse, so they keep offering more and more until either they sell or the company decides to just go around, both are very expensive as they cost both time and labor. I’ve had a $20,000 job that tanked to $500,000 job, and the company just had to eat that loss, it’s not often a big loss like that happens but it’s rough when it does.

ELI5: What is a 'gut feeling' and why is it usually right?

I'd love to know the science/ psychology behind this

Your brain picks up on subtle clues and signals from the situation that you don't consciously notice. It then gives you the feeling of unease or whatever that you feel by releasing hormones or chemicals or something that it feels could be useful in such a situation. They may help you in the event that you need to flee or fight for example. They aren't always right For example, a girl goes on a date with a guy. The guy smells incredibly faintly like blood, he has slightly dilated pupils ect ect. These things are a sign of trouble for the girl and it makes her subconscious give her that 'gut feeling' that this guy is a creeper. It could be right? But the guy may have just scraped his knee earlier and took a painkiller or something.

ELI5: How do potholes form?

A roadway is placed on top of compacted soils. Those soils are usually only tested for proper compaction once per 100 linear feet. Usually the technician testing the soil chooses a relatively compacted ( dense) area to test so they get a passing number. After the soil’s are compacted they place rebar and concrete on top of the soils. Once cars are driving on the roadway they cause vibrations that carry through the concrete and into the soil beneath. Those vibratios, after a while, cause The soils to subside in some areas once subsidence occurs the weight of the concrete does the rest. Gravity pulls the concrete down to fill the hole left by the soil and voilà a pothole is created! To remedy this problem a contractor will usually remove a workable section around the pothole (usually 3 to 4 ft.² around the pothole) they will remove the soil and replace it. Have a technician tested for proper compaction and then they place the rebar and concrete back on top. Source: I’ve been a project manager for TxDoT Edit: removing apostrophes

ELI5: Why do wounds itch when healing, prompting us to scratch and potentially re-damage the area?

Edit: To sum things up so far, in no particular order: * because evolution may not be 100% perfect * because it may help draw attention to the wound so you may tend to it * because it may help remove unwanted objects and / or remove parts of the scab and help the healing process * because nerves are slowly being rebuilt inside the wound * because histamine Thanks for the answers guys.

Part of the healing process is removing any potential pathogens that may have gotten into the wound, so there is an inflammatory response at the site of injury. More blood flows to the area and more white blood cells are recruited to kill stuff, and in the process release different chemicals that cause you to be itchy, like histamine.

[The Expanse] Why does it take 18 months to get to Ilus?

It's said that it takes 18 months to get from Ceres Station to Ilus, but that doesn't make any sense to me. The Ring at Sol is described to be just outside the orbit of Uranus. For a ship continuously accelerating at 1 g (which is something Epstein Drive ships are perfectly capable of), it should take between 12 and 14 days to get from Ceres to Uranus, depending on orbital positions at the time, and taking into account flipping halfway through to decelerate. With a short layover at Medina Station and another two weeks at the other side, it should take about a month to get there. Maybe month and a half if the passengers are uncomfortable with 1 g, or the Ring is further out in Ilus' system. But I can't come up with any way it could take 18 months.

There is a lot of relevant data to be extrapolated too. At what speed does the Sol gate orbit Sol? Does it match Uranus' speed. Does the 12-14 days include the 1G of deceleration burn? I don't recall them specifying where the distance from the Ilus gate, to Ilus itself. Bonus, Sol system is fully charted but Illus might not me, finding lanes and checking of debris et al, MIGHT be an important thing to do (which would lead to lots of burning and deceleration).

How common is it for postdocs or PhD holders to switch research interests?

So I was just thinking, are all PhDs all set for life when they did their research back in their grad student days/post doc days? How rare is the switching of research interest after getting the degree. For example your research interest is environmental microbiology, then after some time you wanna delve in immunology or any of the likes?

Switching topics for post-docs is fairly common. Switching fields completely is less common but I've known people do it (e.g. astrophysics to climate change). You're not deciding on your entire research career just because that's your PhD topic.

argument against a priori knowledge

I was reading a paper that says the following: *"According to one influential argument against the existence of a priori knowledge, there is no a priori knowledge because (i) no belief is immune to revision, and (ii) if there were a priori knowledge, at least some beliefs would be unrevisable."* Please note I am not a philosopher. I am just interested in topics related to philosophy. I studied law. Now, I am thinking how can you explain the statement "every mother has a child" or 1+1=2 or "single men are not married" . How are those not unrevisable? Those are things that are accurate dead on their face and require no or minimal independant verification or observation. Thoughts would be appreciated I would like to learn more about this subject.

Kant responded to Hume’s argument for the existence of a priori knowledge by arguing that in addition to matters of fact, which Kant calls “analytic a priori” ( all bachelors are unmarried) — there are “synthetic a priori” statements which are derived from the combination of basic concepts; mathematics is synthetic a priori because “12” isn’t a concept that is already contained in “7+5” Quine is a modern philosopher who rejects the analytic-synthetic distinction altogether. Quine says that all “analytic” truths require synonymity with facts in the world. Synonymity requires synthetic propositions, so all analytic truths and be reduced to synthetic truth. This seems to be close the kind of argument against a priori that you presented, that we could could revise our previously held a priori truth because or scientific understanding of the world changes.

How do we know the population of deep sea fish?

People bring up that the bottom of the ocean is less known than the surface of the moon, and yet, when I go to the Wikipedia page for Frilled Sharks, I see that it's classified as 'near threatened'. How do we know the population of such a deep sea species well enough to term it 'near threatened'?

In biology, where a species is either widespread, or for some other reason, counting individuals exhaustively is too difficult, numbers are calculated from exhaustively surveying a set area of habitat then extrapolating based on area of known territory. E.g. A bird species has confirmed sightings in 10 different areas that correspond to its known habitat. The combined area of these 10 sites is 1000km^2. Biologists sample 10km^2 and find 20 individuals and so the population is estimated at 2000 individuals.

[40k] Difference in Imperial Guard fire power

How does the Imperium deal with the massive difference in quality and available firepower of their Guard regiments? Say planet A is a backwater world operating at around Medieval levels of technology, how would the Imperium ensure guard they recieve are pitted against an appropriate enemy? Do they bother? Are you essentially screwed if you are from a low tech world?

Each Imperial Guard unit receives their equipment from the Departmento Munitorum. Imperial Guard units such as the Attilan Rough Riders hail from a Feudal world, are in fact much sought after across the Imperium for their maneuverability as a heavy patrol unit and able to operate behind enemy lines with little support. Imperial Guard training differs across each world. Some Hiveworlds round up their worst recidivists and simply throw them into regiments. Others, such as Feral and Feudal Worlders, would already have more combat experience than the average Imperial citizen and therefore require only minimal training to use more advanced equipment during the long haul in-between battlefields.

If we've created a drug "Gleevec" to stop a couple forms of cancer. Why can't we create more drugs like this? (My understanding is it has to do with this cancer's dependence on a particular kinase. Are there other cancers that have similar dependencies we could inhibit?)

You've basically touched on the problem in your question-every cancer is different, and they vary wildly in their dependence on different molecules. The other thing to consider is that Gleevec is used to treat a fusion protein. In CML, there is a translocation of two genes, and the chimeric protein BCR-Abl is formed that is totally dysregulated. What's convenient about treating it is that noncancerous cells don't express this fusion protein, so it can be targeted without affecting the normal healthy tissue. Many cancers aren't caused by these unique fusion proteins though, making their treatment very difficult.

How does becoming a PhD change your academic life on the day to day basis?

What must you more? What can you do less? Pros? Cons? What new academic freedoms you acquire after a successful defense? What are newfound drawbacks? Advice for future postdocs? I am on my third year our of four and want to make the best of it. I am actually majorly motivated to work on my PhD, but I also want to know what to expect. Thanks!

They have to pay you more (but hope you don't know how much they should actually pay you). They expect you to know what you're doing more. You have to get your own permits. You have to find your own funding. You have to motivate yourself to write because you don't have deadlines to meet for someone. You have to fight your own battles (in the literature and in the department). Other than those (pros and cons as you take them, based on your own situation), not much changes. The science doesn't change, the expertise doesn't change. If you're in a prof position you have to do more busywork (committees, advising, uni service, etc) in addition to the teaching. Edit: And you can make undergrads call you Dr. You can make other postdocs/profs do it, too, but they'll think you're a douche.

ELI5: How does a company like Bethesda Game Studios program AI to be constantly changing?

Thinking about it is blowing my mind a little right now. I understand that certain AI never move or do anything else. I don't really understand the Radiant AI system, I guess. Does the AI run on discrete time units? How can a PC make that many choices that fast for the AI for it to be constantly shifting and changing?

In the case of Skyrim, the chances are that while the NPCs are meant to *appear* to go about their lives in whatever fashion they want, keep in mind that they all behave according to a set of rules. For example, Ysolda runs a shop in Whiterun. Now, we can be pretty sure that she'll be on somewhat of a schedule and stay at the shop most of the day, but she still has to get there. She owns a home, so each morning she'll wake up and have a set of goals for the day. If the first goal is to go to work, Ysolda's AI will query the pathfinder to get a route from where she is to where she needs to be. If you decide to interupt her on the way, she'll stop and talk to you. Obviously this interupts her path to work and switches her goals to talking to you. After your conversation is complete, she'll switch back to the original goal of going to work, query the pathfinder for a route, and get moving. By having a set of goals with weighted priorities, you can sort goals by what is most important and execute them. We stopped Ysolda with a conversation, but if we had attacked a town guard nearby or if a dragon attacked, that would have had a ripple effect onto her and triggered a new priority (fight or flight) until the issue was resolved. NPCs could also trigger changes to priority with one another. If two characters cross paths share some sort of relationship (assigned to them on the back end), the goal may be to stop, speak with one another briefly, then carry on. Ysolda stops and talks to her daughter when she comes by the shop. With other characters, the set of goals might not follow a schedule, but goals may still carry some weight. A drunk would have a higher priority of visiting a tavern and would probably be found there at any point during the day whereas the shopkeepers would be more likely to be found there after work. So, basically, even though they appear to do anything they want and sort of live out their own lives, the do likely have discrete sets of goals to accomplish. Not every goal might need to happen every day, but if the AI picks a goal for them and sets them on the path via some subroutine, people appear to go about their lives.

ELI5: If clouds are water vapor, how are there clouds in the arctic? Wouldn't all clouds just freeze almost immediately?

A cloud is made of droplets which condense out from water that's "dissolved" in the air (water vapour) into a visible form of clouds. Clouds that are higher in the atmosphere or that are found in already-cold climates are made of ice crystals. Even on hot sunny days sometimes, and depending on where you live, if you look up and see "wispy" clouds, those ones are tiny ice crystals. In warmer climates you see them at the very top of massive thunderclouds as well, where water is pushed up into thinner and colder layers by the rising action within the growing cloud (which also explains hail). As to why clouds even form in the arctic when it's below freezing, that's because colder air can hold less invisible water than warmer air. When air that contains some water vapour chills down, such as if a wind moves moist air into a colder place or an updraft pushes warm moist air at the earth's surface upwards, it'll condense out just like other clouds do, forming ice crystals rather than water droplets.

ELI5: What does "political asylum" mean, and how does it work?

Wikipedia puts it in terms that most people should be able to understand: Someone may ask for a political asylum when they are frightened to live in their own country. They will then go to another country. If they are allowed to live in the new country this is called political asylum. People who qualify for asylum are those who can show that they might be badly treated in their own country because of their: Race, Nationality, Religion, Political opinions or Membership of a particular social group or social activities.

CMV: After a Certain Point You did not Earn that Wealth

So as a general rule if you want to find out how wealthy someone is and how much money they make the three things you want to know are how educated someone is, how intelligent they are and how hard they work. In general most western nations which provide free education seem to follow this trend. However there comes a point at which outsized wealth becomes completely unjustified. Taking a relatively simple example of Jeff Bezos, a man whose services I use daily. Yes this man designed a good product and to an extent he should be rewarded. But that he is now a multi billionaire for helping code something in the late 90's which had multiple competitors is patently absurd. It is highly likely that if Jeff didn't make amazon someone else would have and they'd now be the multi billionaire. Especially considering most change in management and oversight has shifted away from Jeff and towards managers. There have also been studies done which show that if you already have a lot of money, chances are you will automatically just gain more. This gain is not merit based and you thus did not "earn" it. [https://sci-hub.se/10.1142/S0219525918500145](https://sci-hub.se/10.1142/S0219525918500145) Anyways, CMV! Edit: this post has garnered a lot of traffic. Please be patient while I get round to it.

If you plant a tree, you can eat the first fruit from it. Then as the tree grows, you get more and more fruit. You don’t have to keep planting trees to earn more fruit. No one else planted that tree, it is yours. Eat from it as long as it provides.