[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: what's gdp & what does it say about a country?

gross domestic product are words that i understand individually, but not necessarily together.
i kind of assume it has to do with a richness of a country but i could be miles off. i wonder how many of us are on the same boat.
either way, please enlighten me!

[Assistant] It is the total amount of everything that everyone working in a particular country produces.    Countries with higher GDP's tend to have stronger economies because they are producing more goods and services.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [marvel] how does Caps shield cut through tanks but also bounce off bricks?

[Assistant]
It's the amount of force he puts behind it and how he uses the shield .

When he's throwing the shield, he isn't using his full strength because he *wants* it to bounce. When smashing the metal on a tank, he's using his full strength.

Think of it this way, if thrown softly enough you could bounce a baseball off a window. If thrown with full force it'll go ~~strait~~ straight through it.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Resident Evil] Where do the giant monsters get their mass from?

I'd say it was from eating people, but through-out the series, we see them transform into hulkish monsters out of nothing but the virus.

Mass has to come from somewhere.

Or are all the creatures actually very light and their size is not indicative of their actual weight?

[Assistant]
You know how Nemesis is a giant hulking monster who can toss cars with ease, right?

And you know how Jill, for all her skills, strength and accomplishments is probably like 180 lbs tops, right?

In Resident Evil 3, Jill can straight up shove Nemesis off balance and off a bridge with one tackle push.

So yeah, probably a bit on the light side.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Starcraft] How do I defend my Outer Rim planet against a Zerg invasion without the help of that menace Jim Raynor and that useless Emperor?

[Assistant]
*   10  Supply Depot
*    14  Command Center
*   15  Barracks
*    16  Refinery
*    18  Pause SCV production
*   18  @100% Barracks, start Orbital Command and Marines (up to 2)
        Resume SCV production when Orbital Commands finish
*    19  @100% 2nd Command Center, start 2nd Orbital Command
*    20  @100% 1st Marine, start Bunker
*    22  @150 Gas, start Factory and Reactor on Barracks
    Benchmark: When you start your Reactor, you should have 19 SCVs and 2 Marines.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[MCU] Did Thor have a time limit to proving himself worthy, before Odin would have (possibly) banished him forever?

Asgardians live for a long time. In the first film, it didn't take too long for Thor to prove himself as worthy.

But what if it took decades? Centuries? Would Odin have eventually given up on his son, seeing him as irredeemable, like Hela?

[Assistant]
Odin would have left Thor on Earth for as long as it took for him to prove himself worthy. Turns out that only took a week or so, but if it took a thousand years, so be it. Asgard needed a king who wasn't so hotheaded and wouldn't go looking for fights.

The whole thing about permanent banishment was a lie that Loki cooked up to try and keep Thor out of the way while he took over Asgard.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Star Trek] Why are cloaking devices illegal under Bajoran law?

Presumably Bajor wasn't party to the treaty between the Feds and the Romulans...

[Assistant]
Bajor just came out of an occupation, economy is wrecked, blighted land everywhere, law enforcement is stretched thin, and radical factions trying to perform coup d'etat, with Cardassian supplies no less.

So what would people do with cloaking device? they would smuggle stuff, bring in contraband, aid in kidnappings/piracy, and possibly try to use it to perform coups. Hence why it is banned, it is not like Bajor has a military to speak of that can make use of cloaking device.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Which program is best for me to start learning, based on strong experience with MATLAB and R Suite?

My background involves mathematical, biological and physics-based research, usually between these two platforms (R and Matlab). I'm great at working with them, but have no experience working with any non-biased programs like C+ or Python. Matlab and R are typically mathematical and statistical research software, but aren't necessarily limited to those topics.

I understand that this community is typically used to answer specific questions related to coding issues, so I'm unsure if this is a question that's allowed (if so I apologize and will find somewhere else to ask). I want to branch out into a new programming language that might allow a smoother transition from mathematical coding. I'm looking to begin programming to develop systems that automate tasks for myself and possibly create apps or types of research software, but am unsure which language to start with.

I know it's a general question, but I'm curious if my background and education would be an indicator that I'd have better luck starting with X program vs. starting with Y program. Hope this isn't a stupid question, it's my first post here and I'm just looking for a place to learn and gain experience as well as meet other people with similar interests. Thanks in advance :)

[Assistant]
Python.

Coming from Matlab you'll find numpy (the Python numerical data library) very familiar and as you switch over you'll find all the cool modules which make doing many things in Python supremely easy. Especially for automating and research software (Python is very widely used.)

Things to have a look at: numpy, scipy, matplotlib, pandas, biopython, scikit-learn, scikit-image ...


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Why don't we ever seem to get sick from two things at once?

I guess what Im trying to say is, lets say I have the Flu....or a Cold or w/e bug/virus is going around.

How come in my weakened state that im not infected by a ton of other viruses. It "seems" like it'd make you MORE prone, but I dont think I or anyone i've known has ever gotten sick by more than one thing at a time. Is there any reason for this? Or is it just because our immune system is in overdrive mode?

[Assistant]
Alot of bacterial infections, especially upper respiratory infections, are often preceded by a virus infection.

The virus can disturb the local immunity in the mucosal membranes and make it easier for bacteria to colonize and start an infection. In these cases youre maybe not always "sick" from two things at once, but you would be infected by two different pathogens at once. You could for example get a simple cold first (the virus) and about week later develop sinuitis (the bacteria).


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Batman] At what point was Bruce Wayne at the peak of his abilities crusading as Batman?

Essentially at what time in Wayne's life is arguably the time the Batman was at his best? How did he get to that point and the how did he begin to wear down following on from it?

[Assistant]
About almost a year ago.

Batman was submerged in Dionesium, taking away all scars and wounds on his body while keeping the muscle and all of the callus.

He said it was the strongest and fastest he'd ever been in his entire lifetime.

And subsequently dodged lightning.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
CMV: There should not be separate categories in the Academy Awards for Best Actor and Best Actress.

Well Reddit, my favorite Sunday is almost here! Yes, Oscars Sunday. I've thought for a while now that it's perpetuating gender stereotypes and inequality for there to be separate categories for "Best Actor/Actress" and "Best Supporting Actor/Actress."

I hold the opinion that separate categories based on gender indicate that one's gender predicts one's ability. There are not, for example, separate categories for "Best Male Director" and "Best Female Director." It's just "Best Director." There's no "Best Male Composer" and "Best Female Composer," it's just "Best Composer." There's not "Best Costume Design by a Dude" and "Best Costume Design by a Vagina," there's just "Best Costume Design." There's not a reason for actors to be separated based on gender, particularly when no other nominees are defined by theirs.

I also hold the opinion that separate categories for gender support the (incorrect) notion that one should be thought of as one's gender before anything else. As in, it doesn't matter that you're an actor, it matters that you're a *male* actor, or *female* actor. If this notion is allowed to continue in such a visible industry, I believe that encourages other industries to follow suit. (It doesn't matter that you're an engineer, it matters that you're a *male* engineer, etc.).

CMV, Reddit.

[Assistant] Some roles are only for women and some roles are only for men. Very few if any women can ever play Hamlet because Hamlet is a male role and so unlike in many other categories, an actor's capacity  perform a certain job can be tied to their gender.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: What is holding back science from enabling us to have eternal life?

[Assistant]
As cells in our body die, they're replaced by the body reading our DNA to recreate the cells. However, every time a strand of DNA is 'read', a little piece of it gets used up (like a tail with the end getting clipped). Once it's clipped off, there's no getting it back, and once the tail is clipped completely, the DNA is unreadable.

This process (which I've GROSSLY oversimplified and am probably not even explaining properly) is what makes us age, grow and look old. It's why organs can start to fail and we just end up dying when we can't produce our cells properly.

So far, science hasn't figured out a way to stop this process.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] Why are there so many alphabets (+350), but so few numeral systems?

[Assistant]
I think the best analogy is that of Survival of the Fittest.

All of the modern alphabets or writing systems are essentially equally good at transcribing the spoken word. That's all a writing system needs to do: transcribe spoken words well enough, and not be too onerous to write or read. Some writing systems may have more characters, while others may rely on digraphs for certain sounds, some may work well carved in stone while others look more beautiful written with a brush, but they all basically get the job done.

A numeral system has more constrains: it not only needs to be able to represent small numbers that we can count on our fingers, but, at least in the past couple thousand years, it needs to be able to represent very large numbers, and be able to be used in mathematics.

While all sorts of numeral systems can do the very first (representing small numbers), fewer could do the second (representing large numbers) but absolutely none could beat the HinduArabic numeral system in terms of its power at doing all three.

The invention of both zero and a positional notation (the same ten symbols, meaning different things depending on where they are placed) was so simple and powerful that it blew away all the earlier systems (including nearly-similar ones used by both the Babylonians and the Greeks, which were not as simple or powerful).

The HinduArabic numeral system was simply objectively better than any other co-existing system, and so the other systems were just gradually replaced around the world.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Star Wars] Why are Jedi that return to the light forgiven but regular criminals that repent don't have this luxury?

Seems like a double standard. See examples of Vader, Revan, Quinlan Vos.

[Assistant]
Force users are very rare and therefore very valuable.  The movies and books tend to focus on such characters so they seem more common than they really are.  Therefore it is worth the resources to turn someone who has fallen to the dark side back to the light - to an extent.  Even among those Jedi who have fallen to the dark side the ones you have named are exceptional.  Vader is the most powerful force user there is (pre-Mustafar) and Revan is damn strong as well.  Think more of a high-level military commander or politician defecting during a war.  Killing them weakens the enemy while turning them can hurt them more AND strengthen your side.

Low level defections wouldn't be worth a mention in the grand scheme of things.  However, at least in the EU, high-level military defections are referenced.  So it isn't really just Jedi that are allowed to turn but you better have something to offer.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] If you drill a hole in a metal plate and then freeze the plate, does the hole get smaller, bigger or stays the same?

[Assistant]
Reduce the plate to just the material around the hole. That material will contract, shortening the length (circumference). Therefore the hole will get smaller.

If the whole object didn't behave the same way, there would be tremendous forces generated as the bulk material pulled away from the material right around the hole, and we'd see weaker materials actually separating under these conditions. We don't. (There are other ways to prove the whole - heh - acts like the hole lining does.)


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: AlphaGo and why it seems to take so many hours to complete a game.

[Assistant]
DeepMind is a company Google owns that specializes in neural networks and machine learning algorithms (AIs that learn themselves to solve a problem). You may remember their DeepDream project a few months back that produced very trippy images by outputting what it thought was on an image several times over a single image.

AlphaGo is an AI DeepMind developed to play the board game GO, which is a strategy game of perfect information invented by the Chinese c.a 2500 years ago.

.

Go is a very complicated game for computers to play because there are very very many moves you can make at any given time meaning brute forcing it like chess AI's can is impossible in a reasonable timeframe. thus it has been somewhat of an unsolved problem in Computer Science for a long long time.

.

AlphaGo is currently playing a grand champion in Go, and is currently winning, having won 3 games out of 5. this is an incredibly achievement for a computer that taught itself to play go and has developed some form of human-like intuition for go to be able to spot good moves without computing millions of millions of states.

.

Go takes a long time to play on a professional level. each game can take several hours and has little to do with the AI, normal championship games also take hours to complete. this is because there are a lot of moves that can be made at each time and grandmasters take a long time to select the best move out of the bunch. it takes a long time to fill up a 19x19 board to the point neither player wishes to fight longer.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: How do cells retain their information when they replace themselves?

I read that all the atoms in our bodies replace themselves every 7 years. How do we look and function the same, when the cells get replaced? How do they keep their information?

[Assistant]
When people say DNA is the blueprint of the cell, it can almost be taken literally: it contains *all* the information the cell needs to construct a perfect replica of itself and to maintain all of its functions. Cells don't get replaced in the literal sense of the word, rather they divide. With access to sufficient amounts of nutrients that serve as building blocks, they copy everything inside them (except the mitochondria, but that is a long story not directly relevant to this question). The DNA instructs the cell to copy everything and in what order to do so, how much to make of each organelle and protein etc. In the end you are left with a body built of new atoms, but that functions and looks the same as before.

Think of it like this: If you change the bricks in a building as they break or need replacement, you will after a while have replaced the whole building. The building however looks and functions the same, because you replaced all the bricks with ones that are identical. It's the same way with your body: cells divide and "replace" themselves, but it wouldn't make sense to call them completely new as they are identical to their mother cells. If one carbon atom in your body is replaced with another carbon atom, you still have a carbon atom. Atoms don't have an identity; one atom is no different than another atom of the same kind.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why is mass surveillance by the government on Americans not considered a violation of unreasonable search and seizure?

[Assistant]
The legal reason is because you do not have an expected level of privacy while using internet services. Now *you* might think you do, but in a legal since you do not.

Because you are using the services of multiple privately own companies to access the internet, you are no longer acting in private, you are acting in "public".


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Why are we taught Math that I'll never use out of high school instead of things like balancing a check book and paying taxes?

I don't get why I'm learning how to do Algebra when I have no clue how to do any "real life" skills? To be honest I don't even know where to use this math in real life.

[Assistant]
Believe it or not, math teaches you how to problem solve. Every math problem that we analyze forces us to use many, if not all, of the detailed methods of problem solving.

Successful problem solvers pay attention to detail, they examine all elements & variables at hand, and they stick to a plan or formula -- all characteristics that are heavily reinforced by learning and studying math. It takes discipline to learn math and it takes discipline to focus on solving real-world problems even they aren't math related.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Why are some people are smarter than others?

Why do we all have different levels of intelligence? Are we born like it? Or is it how we are brought up?

[Assistant] Some of it is genetic; certain people are just born with the capacity to pick things up more quickly than others. But a lot of it is also because of how that person is raised. The line between the two isn't exactly well established. Also, keep in mind that there are lots of different ways of being intelligent. Some people are very creative; some people excel in a few certain subjects. Some people generally just tend to learn quickly.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Harry Potter] Is it possible to build a magic detecting machine?

In the books, it's often said that electronical devices don't work in Hoghwarts cause there is too much magic in the air. But this do imply that magic somehow interact with electromagnetic waves, so it should be possible to build a device that picks up this interference, basically creating a magic detector.

Also, if magic do indeed act as an electromagnetic interference, would it be possible to build "magic proof" machinery capable of operating in highly magical areas?

[Assistant]
We don't know *why* certain technology doesn't seem to work around magic, but it is *probably* predictable on some level.

If nothing else, you could probably build a machine whose job is to perform calculations, and if they're accurate it turns on a green "no magic detected!" light. If the machine can't function due to magic, the calculations don't work, the light goes off.

The problem is that you probably couldn't make it activate a *siren* or something, since that could malfunction, too. Maybe you could build a transmitter, and a far-away device would activate if the signal ever stopped, sort of a dead-man's switch.

Kind of makes you wonder what all those cold war number stations were *really* for, huh.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: How come our bodies don't already have a resistance to the common cold? We get it a lot, so shouldn't we be resistant to it?

[Assistant]
I'll expand on the other comments.

Yes, there are several viruses that will result in the common cold, the most common being rhinovirus. The fact that there are multiple viruses that can give you the disease is NOT the major reason that you can get the cold more than once, since you can be infected by the same virus, like rhinovirus, many times in your life. This is because the virus mutates very quickly.

When human cells in your human body replicate, they have to create an exact copy of your DNA. Your cells do this very, very efficiently and effectively because there are *many* methods of fixing mistakes in your DNA. When viruses replicate their DNA/RNA, which is the part that they inject into you so you get sick, they (usually) *do not* have any way to fix mistakes in that DNA/RNA.

These mistakes in DNA/RNA lead to proteins (little parts in cells that actually do work) that have slightly different shapes. After infection with rhinovirus for the first time, our immune system will be trained to recognize the very specific shapes of the proteins that come from this virus. However, since the virus can mutate so quickly, the second time that you're infected by rhinovirus, the proteins from the virus will probably be a different shape than last time so your immune system can no longer fight it off effectively.

Edit: If anyone has specific questions, I'll literally be sitting here all day.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: If electric vehicles are the way to go to reduce emissions, wouldn't charging them use up a lot of power, therefore still being costly and polluting? How does it work?

I know very little about today's climate actions despite routing for them, so I just want to take an opportunity to better understand them. How some things may just be temporary solutions or revolutionary ones.

I do not want climate change debates, I just want to know if powering electric cars has its trade offs or are really going to help.

EDIT: Woah, this my most upvoted and answered post since joining the site. And by a huge margin too. I really only expected like two comments.

Thank you all so much for all the answers, they've been very informative!

[Assistant]
There are really 3 answers to this question.

1 - You might not be using a source that pollutes.  Maybe you get your electricity from solar, or hydroelectric.  This is not a very satisfying answer because it doesn't apply to everyone.

2 - Large power plants are much more efficient than a car engine.  If you burn 1000 gallons of gasoline at a powerplant and send it to 1,000 cars, you'll get more miles than if each car burned just one gallon of gasoline.

3 - Electric cars have regenerative brakes.  Regenerative brakes are great.  Imagine you're riding a bike down a hill and then up a hill... it's much easier if you can build up speed and then coast up the hill, only pedaling a little.  Well, regenerative brakes are something like that - recapturing energy and then letting you use it later.  Regular brakes on cars just turn the energy to heat - like riding a bike down a hill, stopping at the bottom, and having to pedal back up.  You don't get to reuse any of your old energy.  And theoretically you could just put regenerative brakes into gas powered cars... but then you would need to load up the car with batteries, and then you'd have a hybrid vehicle.

So, #2 and #3 definitely have a real impact for everyone, even if #1 only impacts some people.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
What did Heidegger mean when he stated that cybernetics marked the end of philosophy?

This is probably a poorly formed question, because my knowledge on the topic is very sparse, but what did Heidegger mean when he stated that cybernetics marked the end of philosophy?

[Assistant] In a word, he means that cybernetics is exemplary of the way in which thinking has today become predominantly calculative ("means-ends" oriented), and the converse, that "being" in our atomic age means "being-replaceable" or "disposable for consumption in the planning of the whole."


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: If light doesn't have mass, why can't it escape the gravitational pull of a black hole?

[Assistant]
According to general relativity, gravity is not a force, but the curvature of spacetime itself.

Photons follow straight lines through space, but in a curved spacetime those straight lines might look as though a force is acting on the photon to an outside observer.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Indiana Jones] How the hell does this guy still have a job as a professor? Hes at his office for all of two seconds before going on another adventure.

[Assistant]
Indie is an archaeologist that operated in the early 20th century when air travel and telephones were still novel things.

It wasn't uncommon for people in his profession to disappear on an expedition for months or even years at a time.

Also, consider this guy from the perspective of the people in charge of his university:

Indie is some guy who flies around the world packing a whip and a gun and is known to jump out/off/into dangerous situations.

When Indiana Jones is on an adventure he always sending back priceless artifacts and research journals full of information that no other archaeologist would ever dream of finding and he may or may not have saved the world a few times- that last one is still up for debate but considering it's *him* there is probably some truth to that.

When Professor Jones is teaching, half the student body wants to have sex with him and he has a nasty habit of attracting Nazi's like a bad case of bedbugs.

Which would you prefer?


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5:Why aren't digital movies way cheaper than dvd's?

For example: Say a movie cost $12.99 on Itunes or Google Play. Why? They no longer have to have a dvd manufactured which requires a factory and workers or have it shipped (trucks, drivers) or pay for overhead such as a store with employees to sell it. I realize there is still going to be some overhead cost but it seems like they should be way cheaper. So should songs too but I am more wondering about the cost of movies.

[Assistant] The cost to manufacture a DVD is mere pennies, so it was never a major factor in determining the price in the first place.  It's all about finding a price point that maximizes their profit.  Too expensive and not many people will buy it.  To cheap and they don't make very much money even when lots of people buy it.  Somewhere in the middle must exist at least one optimal price that maximizes their profits.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Why are train tracks laid on crushed stones/pebbles?

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

[Assistant]
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.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
How come vaccines dont pass from mother to child?

If they share the same blood before birth, which Im 90% sure they do, wouldnt their immune system keep information from when the mother got vaccinated?

[Assistant] The mother and the fetus do not share the same blood. The function of the placenta is to facilitate the exchange of nutrients, gases, and wastes while keeping the blood supplies separate. There are a type of antibodies called IgG that can cross the placenta. They give some protection to the developing fetus in utero. After birth, IgG and IgA antibodies are transferred to the baby through breast milk. While the baby is breastfeeding, it has the same immunities as the mother does (including those the mother acquired through vaccination). Babies start to make their own antibodies by three months, but their immune systems will be supplemented by maternal antibodies until they are weaned. After weaning, maternal antibodies in the baby's blood eventually degrade, so they will have to be vaccinated to develop their own antibodies.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Why do french fries taste awful if reheated, but something like pizza is comparable whether fresh or reheated?

Other foods don't reheat well, too. Rice, macaroni and cheese, etc. Why?

[Assistant] I assume you're asking about microwave reheating? Microwaving essentially boils your food. Oils will make your food more soggy, water will evaporate, drying it out. Something crispy like a fry becomes soggy. Something moist like rice becomes dry.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Star Wars] Why do Jedi bother learning how to duel with lightsabers when the only enemy that uses them has been dead for a thousand years?

[Assistant]
You try attacking a lightsaber wielding Jedi with a blaster and see what happens.

Other than still being quite effective on the battlefield (I'd say they're even more effective when they don't have other wielders to stop them) lightsaber rituals are a hallowed part of Jedi doctrine. They are a symbol of a Jedi's authority and a personal expression of themselves. They also serve to teach young apprentices focus and discipline and the importance of the physical aspects of being a Jedi and the Force in general.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: What is it that footballers (soccer players) wrap around their wrists all the time? Why do they do this?

So many players have wrists wrapped or taped in something, why do they do this? Can they not take jewellery off? Is it somehow supportive?

[Assistant]
Just wrist support, isn't it? It's quite easy for a footballer to land awkwardly on their hand/wrist, especially if they're a fast but comparatively small attacking player. Or if they're diving.

Jewellery is banned at pro level.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: if ships with sails are heading the opposite direction as the wind is blowing, how do they move forward?

Title.
Edit: Wow front page. First post to do that. Thanks for all the answers. Definitely makes it easier to understand.

[Assistant] Ships can't sail directly into the wind, but will take more of a zigzag path in the general direction.  The sail generates "lift" as if it was a wing, and combined with a few other factors, can generate enough force to move the boat forward.  The zigzag pattern allows it to sail towards its destination without going too far to one side.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: What does Verizon ending phone subsidies mean for their customers?

[Assistant] Not particularly much. You now have the option of buying the phone up front (~ $650 for a high end phone) and paying $20 less per month or getting a payment plan, which is basically the same price you were paying before except you're not "paying an early termination fee for breaking a contract", you're "paying off the phone".


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Avengers Infinity War] Bruce Banner turns into the Hulk at the last last minute in the battle of Wakanda. What happens?

The standard answer here might just be "nothing" Thaos will probably still try to embed him in the rock just like the Hulk Buster but there is one big difference between The Hulk Buster and The Hulk; Anger. There is no max power for the Hulk, as he gets angrier, he gets stronger. Sure Thanos beat him already without using a Stone, but Hulk is now pissed, can anything really stop him?

[Assistant]
There is nothing in MCU currently that supports the Hulk getting stronger as he gets angrier. Even though that is a major factor in the comics.

Especially considering that Hulk was on Sakaar for 2 years, if his power kept ramping up because he is always angry, then he should have been able to beat Thor with zero issue.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Is it wasteful to leave a power adapter plugged in to the wall when it's not connected to a device?

I'm guessing that there is a certain amount of power that gets "lost" when 1) the adapter is plugged in to the wall socket, and 2) my phone / laptop / whatever isn't plugged in to the other end. I'd also guess that this loss is a drop in the bucket compared to energy losses happening while power's in transit from the plant to my house...

So, what's really going on here? Is this really wasteful? Could I save a few bucks a month just by unplugging an adapter I'm not really using anyway?

[Assistant] it depends on the adaptor. some will use a very small amount when no draw is placed on the unit. others will use the same with or without load, older power packs are bad for this and can get very hot if not connected.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Butter is a dairy product. Why, then, can butter be unrefrigerated but milk or cream goes rancid so quickly?

My friend ate 2-day-old risotto on the stove. Why isn't he dying?

[Assistant]
Water content has a lot to do with it. The ability of bacteria to degrade the butter is controlled by the amount of water present. It has to do with the activity (in the chemistry sense) of the water. The available water is bound to other molecules and not available to bacteria that need it the water to survive.

Water can also hydrolyze fats and proteins creating rancid flavors.

Also, a lot of the compounds that taste good are easily oxidized and the oxidized forms can taste bad. Like that old ass jar of olive oil in your cupboard...it tastes like crap because it has gone rancid. It smells bad, but not because of bacteria. Often food will smell bad, but the bad smells are not the result of pathogenic bacteria and will not necessarily make you sick.

I am a geologist, so this may be a little simple.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Star Wars] What if Palpatine died from an aneurism shortly after the Geonosis Campaign ended?

A thought I was having was what if Palpatine just died of natural causes maybe a day or two after the Geonosis Campaign ends? Say he goes to take a nap, happy that the war is beginning as he planned, but during this nap he has an aneurism and died. How would the war progress? How would the republic change? What would Count Dukoo do? How would the timeline be changed?

[Assistant] Palpatine's goal was never for either side to win the war, just to drag it out to give himself more powers. Dooku wouldn't know that, so he'd be fighting the war to win. The Republic wouldn't have Palpatine's inside knowledge of the other side to help them out, so they'd be in real trouble. The separatists may have won the war.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[NOWAYHOME] so were the arms controlling doc ock or what?

Just thought about this and its been a couple months now since i saw the movie so i might be missing something so i apologise in advance if this is a really simple answer lol

During the bridge fight with Doc Ock. Hes getting the upper hand until he snatches a bit of nanotech from peters suit and it pairs with the iron spider suit. The arms then start doing what peter tells them to do and saves the woman in the car.

In this movie and spider-man 2 it insinuates that the arms were telling Otto what to do so wouldnt he have been freed once Peter took control?

[Assistant]
There are multiple things happening at once.

Otto arrives in the MCU universe with the arms' AI inhibitor chip blown, meaning the arms are controlling Otto's intentions and controlling the movements of the arms themselves.

Next, Spider-Man's nanotech binds to the arms. At this point the nanotech is able to control the movement of the arms. This would be akin to handcuffing someone or grabbing your wrist and preventing you moving it. Doc Ock is now essentially restrained by the nanotech, but the AI is still influencing Otto's thinking.

Lastly, Peter makes a new inhibitor chip using the Stark fabricator. The inhibitor chip is installed, restoring agency to Otto Octavius and essentially turning him good. The nanotech is no longer required to restrain the arms, so it is restored to Peter.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why can't we convert greenhouse gases into another gas that doesn't trap heat?

[Assistant]
CO2 is a very low-energy molecule. In order to break it apart, you need to add energy to it.

Plants do this using sunlight as an energy source for photosynthesis, turning CO2 and water into sugar. Whenever we eat the products of those plants, we eventually reverse that process, turning the sugar into CO2, water, and energy.

The real problem with our greenhouse gases is that normally that cycle of plants taking in CO2, plants being eaten, and then animals exhaling CO2 is a closed cycle. The amount of Carbon between the atmosphere, plants, and mammals remains pretty constant. However, millions of years ago, there were some trees that didn't get eaten by bacteria when they died (there just wasn't a bacteria that could eat them yet back then).

This resulted in a lot of dead trees capturing carbon outside of the natural cycle. Those trees eventually got buried underground as the Earth shifted around, and over millions of years have broken down, and are now what we call fossil fuels.

Whenever we burn fossil fuels, we reintroduce that carbon into the cycle. Without more plants or animals for the carbon to live in, all that extra carbon in the cycle ends up in the atmosphere.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Why are pelts worn with the fur outside?

Recently saw the Revenant and got curious.

I never understood why pelts are basically worn with the soft plushy fur thats nice to feel on the skin  outside, and the rough stiff durable leatherskin that holds the fur inside, while it would do way more sense the other way around.

The only argument I can see would be insulation due to trapped air in the fur, but that doesnt make the deal for me as fur inside for wearingcomfort has *still* air trapped inside.

[Assistant] Its the same reason that fur on the animal is on the outside.  The fur can catch moisture and snow and hold it away from us, so that it doesn't melt and then freeze like it would on cotton or wool clothing.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] Is it possible for the Great Attractor to be a Hypergiant(?) Black hole?

[Assistant]
It's always important to keep in mind, a black hole is *not* a great cosmic vacuum cleaner. It doesn't have a preternatural ability to suck up everything in its path.

What determines the strength of an object's gravitational pull is, more or less, its mass and its distance from us. A black hole is special because it's compact. This means you can get closer to it while still feeling all of its mass. But from a distance, it gravitates just the same as anything else with the same mass.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
If two particles are entangled, and I measure the momentum on one while simultaneously measuring the position of the second particle, wont I now know both the position and momentum of the second particle at the same time, violating the principle of complementarity?

I was just reading on quantum entanglement and this came to my mind, and I couldn't think of any solution.

[Assistant]
You cannot perform two measurements on a system at the same time. Quantum physics doesn't really care if you say your system is made of one particle or two - in any case you can't measure two properties at the same time. You can perform measurements that ask how different subsystems of your system are correlated to each other, but you cannot get two measurement results separately at the same time. At least not as long as you perform both at the same place. If you however perform the two measurements at different places, then relativity tells us that there is no clear notion of which one came first and from that alone you can see that in this case the simultaneity-aspect can't play any role.

Example: If you entangle two particles in spin and send them apart and then measure that one has spin up in z basis and one has spin down in x basis, then the measurement result of the second particle will give you no information about what you will measure now when you measure the first particle in x basis. Since the first particle is now in the spin up eigenstate of the z basis, the measurement for the x basis will have a perfectly random result.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: How does an automobile's gearing affect its torque versus its top speed?

What do they change/how do they use gearing to affect either, and can there be aspects of both with the same gearing?

[Assistant]
The best way to explain this is to compare it to a mountain bike with multiple gears. The first gear has a large sprocket and it's good for getting off from a stop or going uphill and through mud, sand and snow. You won't be able to go very fast but you have all the torque you need to power through the terrain. At the other end you have the final gear, it's extremely difficult to use this from a stop but once you're up to speed you can really get moving.
The gear reduction in a cars transmission works on the same basic principal.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Pacific Rim] Why do the pilots need to talk at all if they're already in each other's heads? Wouldn't they already know what the other wants to do before even saying anything?

[Assistant] It's a logging feature for command to be able to get general notions from their pilots. While the two are indeed closely integrated, they are trained to verbalise many of their intents for the benefit of higher ups that need that information for broader tactical awareness.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: How does electronic data storage work?

When I speak of data storage, I'm referring to anything that is used for storage purposes. For example, what differentiates the methods of storage between credit cards, CDs, cassette tape, USB drives, etc?

I have always been curious about this kind of technology that we take for granted, as I was never taught how it works in school.

[Assistant]
The history of computer data storage is long and super interesting. Lots of people have had lots of interesting ideas about how to convert some observed physical phenomenon (like magnetism) into something that a computer can use. Some of the early computer were even designed with one type of memory, and then some totally different but better kind came along, and the computer would be retrofitted with the new memory.

Credit card use a magnetic stripe. You might have made a little magnet as a kid: you take an ordinary needle, stroke it against a magnet, and it turns the needle magnetic. Well, it turns out that you can place a magnetic film on a long roll of "substrate" (usually plastic these days). The magnetic film is really a whole series of little "islands"; each island can be magnetized separately. If you "zap" one portion of the tape a jolt of electricity (technically: make a strong, directional electric field) it will magnetize just the islands close to the field. The little fields can be "read" separately.

You can also put the magnetic "stuff" on a disk, and you get a disk drive, or onto a drum, and get a drum. Drums are long obsolete.

CDs work totally differently. With a CD, you zap it with a laser, and burns a little pit in the plastic substrate. Or, the CD is made with a sort of dye solution, and zapping it with a laser simply turns the dye a different color.

USB drives use what's called "flash" memory; it's fully electrical and uses little capacitors to hold or not hold a small electrical charge.

And, over the decades, people have come up with dozens of other mechanisms. IBM once made a giant micro-fiche machine: you give it a bunch of data at once, and it would flash lights in a pattern at unexposed film stock. The machine would then automatically process the film and place it into a little niche where it could be read from afterwards.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Shadow of War] Can Talion enslave humans?

Or is his mind control strictly limited to Orcs, beasts, and such? Can sufficiently brutish, weak willed, or savage humans be controlled by him and his ring?

[Assistant] He cant affect all orcs, the strong willed ones are impervious unless he shamed them to break down their will. Therefore the mind control is based on willpower and not a racial trait. So if there are sufficiently weak willed humans out there, then he probably could control them. Same with hobbits, elves, and dwarves. Although elves and dwarves seem naturally strong willed.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [general fantasy] If you turn into a vampire as an obese person, are you stuck with that body forever?

[Assistant]
The answer can be varied depending on the background (Story wise) of that particular strain of Vampire.

There are stories of truly ancient vampires transforming over time into something more sinister looking. Their human aspects give way to the bestial predator that lies within making them true monsters.

But in general, more times than not, once you are given the gift/curse you are frozen physically. This is why some lines forbid the transformation of children or the elderly.

Some Vampire lines have strict rules about who should receive their gift and will only bestow it on those who meet their standards (Beauty, sophistication, talent, aptitude for good or evil, whatever they might be)

An obese mortal who finds themselves suddenly immortal may benefit from the ability to shapeshift or cast themselves within an illusion that changes their appearance.

All this being said -there are as many variations of Vampire as there are stars in the night sky. Any sentient being who depends on the blood of mortals may lay claim to the title of Vampire but that doesn't mean they have the same origins.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
CMV: Star Wars fans didn't get the sequel trilogy they wanted, but they got the one they deserved

I haven't seen The Rise of Skywalker yet, and most of you haven't, so no story spoilers here, thank you.

But from what I've read from reviews, is that it's a mess that tries too hard to course-correct after the last movie, while over-relying on your nostalgia for the series.

I'm a very casual fan of SW, but throughout the course of the new movies, I've been perplexed with how strongly other fans have reacted to each film. And now, if the reviews are true, with the mess we have in our hands, I gotta say, maybe you earned it. I'm not talking to every single fan out there, I'm mostly talking to the vocal minority. Those that made five hour rant videos about how much The Last Jedi sucked, and all those people watched and cheered them on.

Let's look at the big picture. After the disappointing prequel-trilogy, that fans loved to hate (before we got prequel-memes), we get the most fan-servicy movie yet, with The Force Awakens, that is basically a remake of the New Hope, with a touch of modernisation. The implied message being, forget the prequels, this is what you loved, right? Brought back the old characters/actors too. Most fans liked what they got, but there were also a vocal minority that deemed the movie too safe. Personally, I tend to agree, but I didn't mind it too much.

Studio listened to the fans, and we get most bold SW-movie yet with Last Jedi. And fans hated it. Like, I have never seen a movie that got so much hate than the Last Jedi. Like, holy shit, seriously? There are hundreds of videos and blogs online analysing every single frame of that movie, picking it apart and destroying it. It wasn't what the fans expected of a Star Wars movie, it didn't take the legacy of the film series too seriously, etc. It wasn't a perfect movie, it had its flaws, but it didn't deserve the beating it got.

Side note: I know that it might not be the same fans that complained about Force Awakens being too safe and Last Jedi being too bold, but I'm honestly betting lot of them were the same.

Lo and behold, the studio hears your cries, the first fan-boy director gets rehired for the next one, and apparently we have a movie in our hands, that actively tries to undo the last movie, while doubling down on the nostalgia. And it's apparently worst of the bunch.

And now we get back to the headline of this CMV. That this sequel trilogy might not be what the fans wanted, but it sure is what they deserved. Bitching and moaning with every movie, every plot point, every actor and character choice. From Mary Sues to Holdo and bullying the actor of Rose out of social media. You were loud enough and they listened, and this is the result. I hope you're happy, but I think it would have been better for all, fans included, if they had just shut up, not take it so seriously, and tried to enjoy the movies as they were along with everyone else.

[Assistant]
The idea that people who love something passionately "deserve" the object of their love ruined completely *just because they've reacted negatively to previous attempts at ruining it* is quite insane to be honest. It seems a lot of people are unable to comprehend that this is a free world where it's people's prerogative to give their hard earned cash to whoever they choose, and the job of the entertainment industry is not to try to shame them into giving up their money for soulless unentertaining bullshit but to compete with each other **in serving the customers the best**. Some large corporations and the journalists in their pockets seem to operate on the illusion that customers owe them praise and money regardless of how shitty their products are, but for some strange unfathomable reason this doesn't seem to work out too well for them. It's not the customers who are 'entitled' for expecting quality products, it's the industry for expecting praise for absolute turds they shit out.

Oh, and the idea that Disney 'listened to the fans' and 'this is the result' is absolute bullshit, if Disney cared about the fans at all the sequel trilogy would look totally different. Disney's plan was to inject a large dose of progressive political messaging into the SW franchise from the get-go, regardless of if the fans liked it or not, and this is the price they are paying for that.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why do DVD's come in DVD cases and not CD cases?

[Assistant] Before DVDs, movies were sold on VHS cassette tapes. The DVD boxes were designed to resemble the VHS movie boxes as closely as possible. Since they are much taller it was also easier to distinguish them from CDs on a shelf from a distance.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: How do doctors tell if someone, dead or alive, has been sexually abused?

[Assistant]
Consensual sex usually involves lubrication - in a woman that lubrication comes from preparation, foreplay, and sometimes external lube.

A consenting woman is more relaxed about the act of penetration, so there's a lot less chance of tearing and bruising of the vaginal tissue.

A woman who does not consent to sex will struggle, and is likely to incur bruises from being held down.  Wrists, thighs, buttocks, waist, throat.

Obviously, an alive victim can tell their story. A dead victim's assault is also likely to be revealed from body positioning, any missing clothing (underwear), the state of the clothing (rips), and if the victim was dressed / re-dressed properly (clothing inside out, buttons lined up improperly,) in addition to physical clues on the body.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: why do sheep, snakes and some other animals have slit pupils? How does this change the image created on the retina?

[Assistant]
Sheep, goats, and a few other mammals have rectangular pupils. It gives them a relatively poor depth perception, but allows them a roughly 300 degree field of vision.

Slit style eyes (seen in cats and reptiles) construct to allow for a much greater range of lighting conditions.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[DC] why does deathstroke wear orange?

He's supposed to be the world's greatest assassin and with that title one would assume that he'd be very proficient in the area of stealth, but I don't understand how wearing orange body armor would help with that. The color would only serve to make him stand out more and make him easier to spot in situations he'd need to hide in (dark buildings, crowds, ect.) so it's clearly not a tactical design choice; so why does slade wilson wear orange?

[Assistant] Branding. He commands respect and a beefy paycheck because when he hits a guy, people know it was him. And people know it was him because he's recognizable in the field. *Tactically* the orange doesn't do much, but *financially and psychologically* it's very useful.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] Can a moon have a moon? What limits the "levels" of satellite that can exist in a stable solar system?

[Assistant]
Its thought that Iapetus, Titan (moons of Saturn) and Callisto (one of Jupiter's moons) as well as our own moon, are the four within this solar system, which are capable of having a submoon of their very own, of around the ten kilometer across scale, and holding them in stable orbits.

 Whether they do or not is going to be tricky to discover, because ten kilometers can look like an awful lot of nothing in space. To put it in perspective, our own moon could have such a submoon, and we might never know of it, depending on exactly how it orbits.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Are the vaccine efficacies for COVID vaccines able to be directly compared?

First,  sorry I missed the AMA (UK based so time zone issues) hopefully someone can comment. My question: We have all heard the quoted 95% for e.g Pfizer and 70% effective for Oxford vaccines.  But it looked to me like the underlying study outputs and processes make those numbers completely incomparable. For example,  Pfizer only tested to confirm  (by PCR)  symptomatic patients,  whilst Oxford tested (at least in the UK cohort) weekly regardless of symptoms,  and as a result picked up a huge number of asymptomatic infections (almost half of the UK infections seen in the study) and included those in calculating its 70% figure.  Surely this means that on a comparable basis the Pfizer efficacy would be much lower? How can we compare them?

EDIT: a number of commenters have pointed out that my question was in fact based on a misunderstanding (I think based on the UK study report alone and not the pooled data article),  and that the Oxford efficacy calculation  appears to have only looked at the symptomatic cases so they are actually more comparable than I had realised.

Thanks to those commenters.

The quote from the Lancet article in the results section is that:
"The primary objective was to evaluate the efficacy of ChAdOx1 nCoV-19 vaccine against NAAT-confirmed COVID-19. The primary outcome was virologically confirmed, symptomatic COVID-19, defined as a NAAT-positive swab combined with at least one qualifying symptom (fever 378C, cough, shortness of breath, or anosmia or ageusia)."

[Assistant]
*In theory*, efficacy is efficacy (in this context; the expected ~~reduction in virus spread~~*reduction effect on some criteria associated with the virus*), so, being one and the same, it should be perfectly comparable.

**But**, as you correctly pointed out, if people use different methods to determine that efficacy, by applying different criteria and essentially define efficacy itself differently (i.e. 'determining all cases' vs 'only determining cases where patients **suffer** from negative consequences of an infection'), then it's not accurate to compare them as they're two different metrics.

It would be interesting to have Oxford rerun their data with the same application of Pfizer's criteria (the reverse might not be possible, since Pfizer inherently excluded data from being gathered), to produce a comparable result (though it's fair to debate which of the methods is more accurate / appropriate).


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[FNAF] Why are we using these incredibly advanced robots to serve pizza?

Sure, the first few generations were haunted but otherwise normal animatronics, and you can't really mass produce "possessed by murdered children" without raising some eyebrows at the investor meeting. But in the later games, these robots are just robots.

And they are more advanced then *anything else on earth*.

As of the most recent game, they're unambiguously true AGI, the holy grail of computing for generations, and even before then they were bounds ahead of anything we have today. Like, no joke, Freddy Fazbear Entertainment might legitimately have the most advanced robotics in the world. They're putting out things that leave the US Military in the dust.

And they use them to serve pizza.

I know that the higher ups are not exactly known for their...perfect business sense, but *someone's* got to have stood up and considered that there must be better ways to make money with the most advanced AI in human history then giving it instructions to tell table 5 their order's ready?

[Assistant]
well, all the games in the FNAF franchise take PLACE in pizzerias.

how do we know that the robots arent used for military purposes off-screen?

infact, for all we know, the "pizza-bots" could be LESSER models and military robots are even MORE advanced than the ones we see in security breach.

does the FNAF lore really expand on the world at large?


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: How do commercial fishers know what they are going to catch?

They will seek out huge loads of one species and throw out the rest... but how do they hunt and track specific species?

[Assistant]
Location, depth, bait, tools.

Certain fish are only in certain locations, so to fish a specific fish you must be in a specific location, this isn't necessarily the difference of Alaska vs Florida, but can be location where a certain environment or phenomenon is observed IE: where currents come together, or where certain food can be found said fish like.

Certain fish swim at certain depths, you fish as deep where the fish will be.

Certain fish are attracted by certain kinds of bait.

To catch specific fish you might use different methods or tools, something that is most effective for that kind of fish, it's not always just massive nets.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Traffic jams are often caused by incompetent drivers. CMV.

I am convinced that many, if not most, traffic jams are caused not by traffic volume but by incompetent drivers reacting inappropriately to traffic situations.  I just refuse to believe that traffic jams are inevitable in high traffic flows.  I think that the three main causes would probably be people driving too slowly in the passing lane(s) and thus not letting traffic through, or by opening up a huge following gap in traffic because they're feeling nervous, or overreacting to someone putting their brakes on in front of them and thus causing a chain reaction.   CMV.

EDIT:  To clarify my thoughts further: Fluctuations in speed are really what cause traffic jams.  My contention is that human incompetence is to blame for the vast majority of fluctuations in speed.

EDIT #2:  I understand what happens when cars start slowing down, I understand the impact that has all the way back.  That's not up for debate.  My point is the root cause of the slow down to begin with.  Why do the cars have to slow down?  Discount things like accidents (most of the time you will see evidence of this when it's the cause) or other forms of obstacles in the road.  Someone here posted a really good video of what happens when it's just a bunch of cars going around in a circle.  There was no obstacle but they ended up clumping up anyway.  I think that experiment was set up to fail because they're forced to follow each other too closely and they're not race car drivers.  I still believe that a huge portion of traffic congestion is caused by people doing things they shouldn't be doing and that they could easily avoid doing if they were just paying more attention (and sometimes it's just ignorance).  One area that I'm willing to concede a change in view is  that bottlenecks do play a much bigger role when it can appear there is no cause to the slowdown.  It's undeniable that squeezing more traffic onto the highway in already dense conditions is going to cause a slowdown even if everyone is driving well.

[Assistant]
Technically, you're right. Traffic jams are caused by a lack of competence.

But the level of **competence** required to prevent them in dense traffic is beyond human levels.

Even a split second error can cause a ripple. If the traffic volume is low, this ripple will dissipate; no harm done. But with a high density it just keeps growing until something disrupts it.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Why hasn't AIDS spread through the country, through mosquito bites?

I would assume they are basically needles, and they spread other blood based diseases. Why not the HIV virus?

[Assistant] That is actually a really good question. When a mosquito bites someone, it does not inject its own blood or the blood of an animal or person it has bitten into the next person it bites. The mosquito does inject saliva, which acts as a lubricant so that it can feed more effectively. Yellow fever and malaria can be transmitted through the saliva, but HIV does not reproduce in insects, so the virus doesn't survive in the mosquito long enough to be transmitted in the saliva.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why do people with amnesia forget who they are/who the people around them are, but dont forget what basic things are in the world, such as cars, planes, appliances etc.

[Assistant]
This has to do with how our memories are called upon, and in the case of your question what exactly constitutes a "memory."

Amnesia occurs when there is damage to the pathway in the brain that we use to either store or retrieve memories. This means amnesia can be retrograde (forgetting the past) or anterograde (not remembering new information).

With object recognition, this pathway isn't used at all. There's a separate set of conditions associated with brain damage that affect this, and they don't affect memory.

For example damage to the temporal lobes can prevent someone from naming an object that they see, yet they can still know what it is. This means someone can't look at an airplane and say "that's an airplane," but if you asked them to "point at which picture is an airplane," (giving them the word) they could do it. The opposite is also possible. Meanwhile, a person with amnesia will recognize the airplane, but might not be able to describe to you how an airplane works.

**In short because recognizing these things has more to do with language and is processed in that part of the brain, separate from the part the handles your name and birthday.**


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: hostile witness/client benefits

What are the benefits or advantages of treating your witnesses/client as hostiles during trial? What does it actually mean?

[Assistant]
Normally, on what's called "direct examination" (where the defense's lawyer is questioning defense witnesses or vice-versa), counsel is not allowed to ask what are called "leading questions," which suggest the answer counsel wants to hear.

Here's an example:

> **Neutral** question: "How fast would you estimate Mr. Smith's car was traveling before the collision?"

> **Leading** question: "Mr. Smith's car was traveling 20 miles over the speed limit when he lost control of his vehicle and slammed into the victim's car, right?" (Leads the witness to the conclusion that Mr. Smith was speeding, and as a result lost control of his vehicle, leading to the accident, which was clearly his fault.)

However, if counsel finds that the witness is being antagonistic, contrary, or otherwise not playing ball, they can ask the judge for permission to treat the witness as hostile; this not only lets them ask leading questions, but also to directly challenge their testimony and apply various psychological tools to reframe how the witness views the situation.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Star wars/star trek] Do either of them travel to another galaxy and how far have they traveled?

[Assistant] For Star Wars, their main galaxy has seven companion galaxies that are much smaller. Beyond these, however, like Star Trek, there's a spatial disturbance that prevents travel beyond, though Legends say that the invaders known as the Yuuzhan Vong managed to find at least one safe passage through the disturbance.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Harry Potter] Could a student at Hogwarts ask to switch houses if they were really unhappy?

The sorting hat can't tell the future, and people can change.

What if say a student arrives back year 2 or 3 and has changed as a person? Or maybe they have more friends in another house and don't get along with their own housemates.

Can they ask to just change? Would they be allowed? Have another go with the sorting hat?

Or maybe it would just depend on the current Headmaster, I can't see Dumbledore having a problem, someone like Phineas Nigellus not so much.

[Assistant] It's likely at the headmaster's discretion, probably with the agreement of both heads of houses.  The Sorting Hat takes a bunch of confused 11 year olds, some of which are completely new to the concept of magic in general and definitely Hogwarts in particular, and try and figure out their core personality.  It's not like there's one house that's the perfect fit for each student, the Sorting Hat says that Harry would be good in Slytherin too.  If a student is wavering or can be good in either house, I'd hope there's some sort of petition to switch houses.  Or even if it's not a personality thing, what if you just don't get along with somebody in your house, are you just supposed to live in the same room with your bully or your ex for the next 5 years?  It's not like there's much teacher control about what happens in the common rooms.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[X-Men Days of Future Past] - What happened to the mind of the alternate Wolverine who lived through the new timeline?

So in DOFP film, Wolverine goes back in time and changes the past, effectively erasing and altering the timeline to a new one.

Now he wakes up in 2023 with no idea what happened since 1973.

But surely in this new timeline, Wolverine did eventually meet the X-Men and have new adventures with them. He was after all, teaching history at the school. So did this version of Wolverine just cease to exist once the original timeline one woke up?

My guess was that Charles restores his memories. And by the events of Logan 6 years later, it is implied he does remember such adventures (hence his commentary on the comic books, saying that they're only partly true). Am I correct in assuming that Charles restores his memory and he vas memory of both timelines? Cos that makes Logan an even more tragic film, he has to watch his friends die twice.

[Assistant]
It doubt it would be possible to restore such time-tossed memories, which to his current consciousness, he never temporally experienced.  To do so Prof X would need to be able to transcend linear time in his telepathic abilities; reading a mind in the past and copying from it.

Professor X *can* implant the memories of everything he has seen Wolverine due (complete with the mind-reading of his surface thoughts and emotions.)  As well as the more physical memories of others.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
CMV: Hermione wasn't actually a very good wizard/witch

There is an art trope that "your technique is perfect" is the ultimate dis.  Hermione was extremely smart and had done tons of reading/research.  She had perfect technique.  Yet she never actually made anything magical. Tons of characters in Harry Potter make all kinds of magical stuff. Many even make their own spells and potion recipes. She get's frustrated at Harry when he uses Snape's old book to make perfect recipes because they aren't exactly what the regular book says.  Perfect technique is not what makes great art. Magic is much the same.

Fred and George created tons of brand new magic and they were considered lackadaisical.  Heck almost all of the Weasleys did more original magic than Hermione. To use IT terminology, Hermione was maybe a power user, but certainly not a programmer or computer engineer

Edit: Voldemort didnt invent horocruxes, I never said that. He did invent the insanely devious traps protecting his horocruxes.

Also: yeah we have no idea what happened outside of cannon. That doesnt prove or disprove anything. Just cause it could have happened doesnt mean it did. With zero information, its just as likely it didnt happen.

[Assistant] Hermione made many useful magical things. For example, she made the Dumbledore's Army Galleons and Parchment, both of which were subtle enough that they were able to hide their magical nature even from wizards who were directly handling them.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: If every part of the universe has aged differently owing to time running differently for each part, why do we say the universe is 13.8 billion years old?

For some parts relative to us, only a billion years would have passed, for others maybe 20?

[Assistant] We're simply judging by earth years not relativistic years. Sure technically, certain parts have advanced further in "time" due to the effect of gravity. But according to us here on earth, looking out. There has been approximately 13.8 billion years since the big bang. (A year being the time it takes for the earth to complete 1 full cycle around the sun)


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
CMV: My prejudice towards black people is useful

Lets start with some facts, I support BLM, think theres systematic racism against non-whites in our society, and support progressive reforms.

Ok, with that our of the way lets get to my view.

Im a New Yorker, living in the city for almost twenty years. Recent events have made me re-examine race and my views on them. However, after doing some soul searching, I find my prejudices rather useful.

For example, when I go to a theater, and I see a bunch of black people sitting together, I move to another section. Thats because 9 out of ten times, the group is incredibly loud and would talk during the movie.

When I see a bunch of black and brown teens, especially boys, I tend to avoid them, as my experience tells me that theyre usually obnoxious and many times would try to start fights. (Ive actually seen it happen before)

When Im on a darker street, or in a sketchier neighborhood, and I see a black man walk toward me, Im instantly more cautious. Thats because the only experience Ive had being robbed, and jumped in NY have been by black men. I dont react this way to all black men, but I think Ive developed this instinct almost subconsciously. To describe the type that gets me nervous, thats be the younger black man who dress in a way that appears like theyre not at least middle class.

Now, I dont think this applies to all of black people or even most. I have plenty of black friends, and know its ridiculous to apply one thing to an entire race. I also dont think a race is superior than another race. But being from NY, I think having my instincts and prejudices have helped me avoid danger, conflicts and general hassle. I believe my views are derived from social factors rather than race.

Im wondering if anyone can CMV that my prejudices are useful to have. To me, theyre harmless to people but helpful to me. Thanks.

[Assistant] The way you describe it, it might be less about race and more about attire and attitude. People dress and behave in a way that is deliberately chosen to reflect their subculture and mindset. Thats part of why you can tell some people are gay just by looking at them, because they deliberately try to indicate it. It might be helpful not to think about it as a race thing though, because its not their race that youre judging.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Can any language really be "faster"?

When comparing the "speed" of languages like C++ vs Swift aren't you really comparing the efficiency of the Compilers? I ask because I'm interested in programming for Audio, and it seems like most Audio stuff is done in C++... presumably because it is a low level language.

But comparing Swift and C++, both are Compiled "Ahead of Time" to machine code... Yet I read that Swift is not yet as fast as C++ in many contexts. I don't see audio frameworks suitable for things like virtual instruments in Swift, and my guess is because of performance limitations.

So is there anything inherently faster about a lower level language like C++ vs Swift?  Since they both get compiled ahead of time to native machine code I imagine more efficient Swift Compilers of the future will bridge the gap? Is it because for performance critical programs it can be useful for a knowledgeable C++ developer to take more control over memory management and other things that would be done auto-magically by the compiler of a higher level language like Swift?

[Assistant]
A large part of it is the compiler, yes. However, there are aspects of a language that can make it inherently more difficult for a compiler to make it fast.

A low level language is by definition closer in semantics to the hardware. To put it overly simply, each line of C code might correspond to a handful of instructions of assembly, and that's it.

A higher level language on the other hand may include abstractions that do not map neatly to hardware instructions. So the compiler has to introduce a bunch of overhead to "simulate" that feature of the language in the hardware.

Another important factor is: how many guarantees can you give about the behavior of the program at runtime? For example, in a dynamically typed language like JavaScript a value could be of any type at a particular point in time at runtime. So the compiler would have to introduce conditionals in the output to handle different cases. A smart compiler will cleverly infer the kinds of types that a value could take on at a any given point, but in general you won't have any hard guarantees.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
will someone please ELI5 "dues ex machina"

I don't understand that saying. Is it a reference?

[Assistant]
In ancient Greek plays, tragedies often ended with a God descending from heaven (lowered by a machine, of course) and bringing closure to the plot.

Hence the saying Deus ex Machina (*or* *God from the machine*). It is usually used when someone or something out of the blue brings a storyline to an end which would not have been possible otherwise.

Example: In the final matrix movie, Neo makes a pact with one of the machines to kill Agent Smith. Without the help from that machine, this would not have happened and nothing in the film up to that point indicates that such an event was even a possibility.

Note that the thing interfering in the plot line does not have to be divine or a machine to be called a Deus ex Machina, it simply needs to bring about an improbable change in the story.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Superman] Questions about Superman's diet.

In TAS he says that he doesn't need to eat but he does it out of habit (TAS also says he can't breathe in space though so I'm not sure how accurate this line is). What does he eat? How Does food effect him? Like, does sugar give him energy? Does eating too much make him fat? Does he eat meat? I mean on one hand he has an "all life matters" kind of attitude but on the other hand he grew up on a farm so he's probably used to eating animals.

[Assistant]
In Post Crisis we see that he does eat food regularly but it seems to be more out of habit and tradition than anything else, we see him visit his Mother regularly and has dinners with her, and since this includes pies than he probably doesn't care too strongly about the vegetarianism. We know that he doesn't need food because there are stories where he goes for extended periods without food (e.g Camelot, Final Crisis ect) and he doesn't care. At this point he simply needs the Sun to survive.

As for the "needs to breath in space" thing it tends to vary from writer to writer but it doesn't tend to matter. Most of the time he doesn't need to breath, and the times that he does he can hold his breath for such an indefinite time that he might as well be able to breath in space.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: When meat/eggs go bad, why does cooking them not make them edible?

[Assistant] Sometimes, these little bugs on foods can make us sick. These are called "germs," or "bacteria," and they live on everything - even your skin. But the ones on food can be bad for us, not like the ones on our skin, so we cook the food, and that gets rid of all the bugs. But, like all things that live, they poop (don't laugh! it's true!). So when you eat something that's gone bad, it's had all these bugs living on it for a long time, and they're too tiny to see, so their poops are too tiny to see. But that's what makes you sick, even when you cook the meat to get rid of all the bugs - the poop is still left behind.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why is the societal norm for women to wear makeup?

[Assistant]
It's an evolutionary throw back first and foremost.

Looking young and healthy means that you look like you would make a good partner to rear children with. Women have been grooming themselves so long over the ages that it has just become part of human nature.

Over time make up companies and media have drilled in the idea that being attractive (Young looking, slim, smiling) is the desired goal - creating a cycle.

Edit: "vicious" removed, as really after some thought don't see much positive or negative.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Why do we cringe?

If we see someone hurt themselves, or embarrass themselves, we end up cringing . What's the point in our faces automatically contorting into something so retarded looking?

[Assistant]
What you are describing is empathy. It is a psychological reaction which pretty much relates someone else's body to our own. It exists so that humans could work together better and to have us avoid killing each other in most cases.
Edit: Well, the face reaction is really just us putting ourselves into that persons shoes, and reacting how they would.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Stupid] How would various ethical theories respond, seriously, to the idea that one is morally obligated to put the toilet seat down?

[Assistant] I guess Kant would say that adult men should leave the toilet seat up, out of consideration for the dignity of their fellow rational beings (adult men), but he would have no definite rule as to how women should behave, because he didn't count women as rational beings.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [WH40k] What is the state of male-female relationships in this dystopic future?

[Assistant]
As with every other 40k culture question, "*It Varies*".

For the most part though, humans are still human. They form relationships encouraged and discouraged by the area they grew up in. Some of these are loving (in ways we might not agree with or recognize), some are out of necessity, and some are by random happenstance.

Fraternization is looked down upon in the Guard and the Navy. Still happens, just like on ancient Terra. Significantly more likely to end with an execution than it used to be though.

In the upper echelons of suprahumans things get a little simpler. Space Marines are widely said to give up that particular drive. Sisters of Battle are either chaste or want someone infinitely more pure than you.

Those endless waves of guardsmen have to come from somewhere, right?


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5 Is Lithium the medicine the same as Lithium the battery?

Like, the very same? Does it at least goes through different processings? How the fuck can a metal be a medicine?

[Assistant]
Lithium is the same element in both cases, but it is involved in different chemical compounds.

In a lithium battery the lithium is part of lithium cobalt oxide, one lithium atom, one cobalt, and two oxygen. In the medication it is lithium carbonate, which is two lithium atoms, one carbon, and three oxygen. Atoms behave very differently when in different chemical compounds so while the atom is the same they are very different things.

As for why precisely lithium works to treat some kinds of mental disorders... we don't really know why it works, but it does seem to be effective.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Star Trek] Why were weapons of mass destruction not used during the Dominion War?

I remember 1 instance where a Changeling stole a Roundabout with a tri-colbalt device, and almost blew up the Bajoran sun along with the entire Federation, Romulan, and Klingon fleets. Why were tri-cobalt sun crusher torpedoes not commonly used in the Dominion War. I mean you could sneak 1 or 2 ships under cloak into an strategic enemy systems, and then just blow up the star, killing everyone. Tri-cobalt warheads are not too difficult to manufacture, and the Federation Alliance certainly had cloaking technology, so why didn't they do it. Of course you could argue that the Federation has morals, but what about the Klingons and the Romulans. They could have potentially lighted up the entire Dominion.

[Assistant]
By the 24 th century the explosive yields of weapons are described in terms of isotons as compared with today's convention of using kilotons. However,given that we know the quantity of antimatter and matter used, we should be able to make some assumptions about the comparative yields of the weapons of the Federation.

The current convention is to measure yields in multiples of the explosive yield of 2,4,6-trinitrotoluene CH 3 C 6 H 2 (NO 2 ) 3 . We know that TNT has an explosive yield of 700 calories per gram,(Encyclopaedia Britannica) so we can begin by converting into SI units; specifically the joule. To do this we will multiply the given figure by 4.1868.

1 gram of TNT = 700 calories = 700*4.1868 joules. 1 gram of TNT = 2930.76 joules

Now we need to know how this works in tons. Given that 1 ton is equal to 2240 pounds or 1016.046909 kg we should be able to scale up the explosive yield simply.

Note It is convention to use ton compared to short ton,net ton American or tonne (1000 kilogrammes.)

1 kg of TNT = 2930.76j*1000g = 2930760 joules. 1 ton = 2930760j*1016.046909kg = 2,977,789,639.02084 joules. 1 megatonne = 2,977,789,639,020,840 joules.

According to Einsteinss theory of special relativity the enrgy E,and momentum,p,of a particle are related by the equation :

E 2 =p 2 c 2 +m 2 c 4

However,given that the antimatter is injected into the matter and held by fields around each packet of antimatter until the detonation signal it would seem that the matter is not in movement and therefore p tends towards zero.

E 2 =0c 2 +m 2 c 4

E=mc 2

Where c is the velocity of light and m is the mass of the particle when at rest.

What we will do is calculate for a detonation of 100% efficiency for simplicity. The amount of matter is therefore 3kg (1.5 antimatter mass combined with 1.5 mass of matter,energy must be conserved in any reaction) and the constant c is the speed of light which we will approximate to 299,792,500 ms -1

Using the mks unit system for SI measurements:

E (joules) = 3 (kg) * 299 792 500 2 (ms -1 )

E (joules) = 3 (kg) * 89,875,543,056,250,000

E (joules) = 269,626,629,168,750,000 joules.

E (joules) = 2.6962662916875*10 17 joules.

Now if 1 megaton = 2,977,789,639,020,840 joules; then 1 photon torpedo yields 90.5458953968987946834375526278729 megatons. (90.55 to 2 D.P.)

This has been upgraded recently to increase yield by 5%. (Zimmerman et al. 1998)

This gives 95.73 (to 2 D.P.) megaton yield which rates at 18.5 isotons. This would mean that 1 isoton is approximately 5.14 megatons to 2D.P.

A typical quantum torpedo has increased the typical yield to 21.8 isotons approximately 112.03 (to 2 D.P.) megatons but by using the zero point motion the yield increases to an equivalent of at least fifty isotons. This would give a megaton yield of 257 megatons. In 1987 the Soviet and American stockpile of nuclear arsenals measured 15 gigatons. This is only 58 times the yield of a single quantum torpedo. In fact the detonation of a single torpedo would release more energy than 13 times the explosives ever used in war from the discovery of gunpowder to the 1990s.

TLDR: a photon torpedo is a weapon of mass drestruction by todays standards.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Half Life] What exactly are the combine?

I'm not too brushed up on my half life lore but I did love to play back in the day. What's the lore of the combine? Why are they enslaving earth? What do they have to do with Xen?

[Assistant]
The Combine is an inter-dimensional empire that invades planets to harvest them for resources for an as-yet unknown purpose. It's suspected that they just use said resources to perpetuate their own cycle of invasion and conquest, but it's still somewhat unclear. What we do know is that they have access to sufficient technologies and assets totally conquer Earth within lest than a day, the focal point of which was the 7 Hour War.

Xen was a haven from the Combine for the refugees of multiple conquered worlds, existing in the space between dimensions. When the calamity that befell Black Mesa breached into this inter-dimensional space, it alerted the Combine to the presence of Earth, directly resulting in their invasion.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] Have we ever converted energy to mass?

[Assistant]
Yep, we do it all the time in particle accelerators. Particle accelerators add a lot of kinetic energy to the particles that they accelerate and when these collide, this energy is converted into new and heavier particles.

Take the LHC for example. It accelerates protons that have a rest mass of about 0.9 GeV. When two protons collide, they can form a Higgs boson that has a mass of about 125 GeV, clearly much larger than the mass of the two protons combined (and that ignores the fact that the interaction takes place between components of each of the two protons rather than the entire proton, so the total "input mass" is even less than 2 * 0.9 GeV).

The Higgs boson is not the only particle created in a reaction where the output has more mass than the input. This happens with many particles created in particle accelerator experiments. In fact, the main reason we accelerate particles to such high energies is precisely to create new particles that are heaver than the rest mass of the input particles.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Exactly what is a home owners association and how do they have the authority to issue fines and say what you can and can't do to your own property?

Exactly where do they gain this power of authority over your own land and how do they enforce it?

[Assistant] They don't "gain this power of authority" over your land. Instead, when a person buys property in a "deed-restricted" neighborhood that person is agreeing (in writing) to abide by the deed restrictions (that are typically enforced by the HOA). When these types of communities are formed, the "deed restrictions" are typically put in place BEFORE the lots are sold, not after. Nobody forces a person to live in a deed-restricted community. However, many people *choose* to do so for lots of reasons. Common reasons cited are that it prevents neighbors from doing things that some consider unsightly (parking cars on the front lawn, having junk cars in the driveway, painting the house odd colors like bright orange and purple, letting the grass grow too tall, etc). Lots of people don't like HOAs and deed restrictions. Fortunately (in the US at least) there are lots and lots of places where people can live that are not part of an HOA. Conversely, lots of people *prefer* to live in an HOA-neighborhood because they feel it helps maintain property values and also helps protect against neighbors doing strange or obnoxious stuff to their homes.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[ELI5]What is an MP3 compared to MP2/1 and MP4, for that matter.

MP4 is just video? What are the other two!? I'm so confused.

[Assistant]
MP3 is actually short for MPEG 1, Layer 3

MPEG is a standard for audio-video compression, it defines how audio and video information is mixed together and put into a file that can be easily read by your dvd player, your iPod, anything capable of playing a video.  It ensures compatibility.

When audio and video are stored in this file format, they are stored encoded and compressed following a set of rules.

For example, an Audio CD can store 74 minutes of music - these discs are raw, uncompressed music. If you'd copy the disc on your computer and keep it exactly the same, you would need 650 MB of disk space.

When the audio is stored in the MPEG file, the software that saves the file analyzes the music, tries to determine what your ears can't easily notice and removes these parts to make the file use less disk space, then compresses everything as if you would compress a normal file with WinZip or Winrar.
This way, those 74 minutes of audio would be stored in about 100-150 MB of disk space, instead of 650 MB.

When the standard was originally invented, they had to come up with a method to remove parts your ear won't notice missing easily and make the audio take less disk space. They did and titled it "Layer 1". This method was somewhat lousy, the audio quality was poor, but this was the best they could do. They had to make a compromise between audio quality and the cost of the products playing the music and video.  Making it very good quality would mean the video and audio players had to use very expensive chips that would also consume a lot of power, so the audio and video players would not be very portable.
It might sound silly now, but when this first standard was defined, people had 486 computers and probably the first Pentium computers appeared.

A few years later, the technology evolved enough that they could take some of the ideas they had for the first version (but had to abandon due to that compromise) and also thought of better methods to encode the audio and make it use even less space while retaining more quality... in the end the sound was better while it took less disk space than before. This needed much more processing power, better computer chips, but by this time, the chips were cheap and powerful enough to be easy to go ahead with the plan. So they called it Layer 2 ...

More years went by and the chips got even better, more powerful, which made the group behind MPEG to come up with a new set of methods and tricks to compress audio in smaller disk space and keep more audio detail.... and they called it Layer 3.

This MPEG1 Layer 3 method of audio compression became very popular in very short time, because it was made a standard around the time of Napster, so people started to make audio only files and renamed them to have the extension .mp3 instead of the standard .mpg or .mpeg

MPEG-2 is an evolution of this MPEG 1 file format. It was created for DVD, because by now better methods to compress video were possible without using very expensive chips.  The methods used in MPEG-1 to compress video were designed for small resolutions, generally half the video information a DVD had, and had less quality.

They also worked MPEG-3, which was supposed to be a file format optimized for high definition content (HD) but they decided to give up on it, because they realized the same methods to compress video used for DVD gave good enough results with HD content.

Now MP4 is actually short for MPEG-4, which is a new standard for storing audio and video mixed together in a file, from the same group that made MPEG, but a much more modern one. In this file, video and audio can be stored using several of those methods, just like with MPEG.

In MP4, the most preferred methods for compressing audio are AAC (a bit better than mp3)  and mp3, while for the video part the preferred method is called h264. This h264 method of compressing video is much better than the method used in MPEG-2.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] What's the smallest program that can be called "Linux" and what does it do?

[Assistant]
The core kernel with no modules.

Practically, it would do nothing. You might get some diagnostics to the serial console or framebuffer while it boots, but then to even accept input, you need an init process - something outside the kernel.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Is it possible to have a charged particle in a solution or suspension(other than dissolved ions)?

I know many atoms form ions when dissolved in water for example. But what I am wondering is whether a larger particle can hold a static charge when in a liquid, in the way a dust particle can be statically charged in air? Could particles in water be charged and attracted by an electric field, other than those that are naturally ionised when in solution? I suspect that the charge would quickly be dispersed into the fluid but I am not sure. Are there non conducting fluids perhaps?

[Assistant] Well, you can take proteins for example, which are composed of the 20 amino acids, which include some that are charged. This gives the protein a property termed isoelectric point, which is the pH at which the protein will be neutral. At pH above or below this isolectric point the protein will be charged in solution and be influenced by electric fields.