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

[User] ELI5: We have invented materials that don't rust, so why do bicycles still use chains that turn rusty after a little rain?

[Assistant]
Materials selection is often balancing a set of trade-offs. A chain needs to be both durable and relatively easy to make.

Using a hard material and adding lubricant helps it last a very long time, and that lubricant can also prevent rusting if properly cared for.

Very few materials are as hard and durable as steel, and those materials tend to be super expensive.


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

[User] eli5 How do credit card companies make money out of people that pay their cards in full before the billing cycle and still get rewards?

[Assistant] They get a percentage of each transaction from the store. There are also yearly fees for a lot of the fancier cards. And there are a LOT of people who dont pay their balance on time, and those interest rates take care of it for everyone else.


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

[User] [Marvel] Why are some heroes like a Luke Cage or Iron Fist or Spider-Man seen as more of a "streetfighter/neighborhood hero" than say a Captain America or Iron Man who tackle huge potentially world ending threats?

[Assistant]
Captain America is a government agent and Iron Man is regularly targeted by foreign agents because of how important Stark Industries is to the US military-industrial complex. Both of them travel internationally even if they don't have to fight crime.

By contrast Spider-Man and the Heroes for Hire don't have access to resources like that. They don't even have the money to fly out of New York on a whim.


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

[User] ELI5: How can mobile racing games have real cars/brands while GTA V can't?

[Assistant] Seems pretty clear to me that GTA is satire, for which it is essential to NOT have real brands. The point is to make caricatures, parodies and general exaggerations of real life brands/makes/models/companies/people/pop culture. They would be censored on 99% of the things they said if they used real names, which they would never intend to do anyway.


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

[User] Will the cosmic microwave background noise, thermal radiation leftover from the big bang, eventually fall silent?

[Assistant] It won't disappear, but as the universe expands, the cosmic microwave background spectrum will correspond to lower and lower temperatures, and the energy density will also decrease.  Thus, it will get harder and harder to observe.


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

[User]
Why does stuff in the Universe like to rotate?

Everything out there spins. From galaxies all the way down to quarks. I read "the solar system condensed and started to spin..."

Why does everything like to spin? And for a bonus question; does stuff always spin the same direction? I mean, except for cases where a planet gets knocked sideways, etc.

[Assistant] Imagine you have a massive cloud of dust.  The odds of the total angular momentum of this cloud being exactly zero is negligibly small.  This means the cloud is rotating very very slowly with a defined direction.  Now consider what gravity does to the cloud.  It will cause the cloud to collapse in on itself.  As the cloud collapses, the angular momentum is conserved, but the size decreases.  This means the rotation rate must increase significantly.  Now you have a smaller cloud rotation more quickly.  Stars and planets can form from this cloud, with higher likelihood that these stars and planets have a rotation vector in the direction of the cloud's rotation vector than other directions.  Our solar system is a great example of this.  The sun is rotating, and the planets are orbiting and rotating with very similar vectors, with only a few exceptions.  This is because they all formed from the same cloud of rotating dust that collapsed on itself.


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

[User] [MCU] The Sokovia Accords are still in effect right? so is Spider-Man an unregistered super?

[Assistant]
Who said he's unregistered?  Tony could've put a pen in his hand in New York and said, "before we go, sign this...it's just a formality".

It would look very bad if he brought in an unregistered enhanced to force Cap and team to comply with the Accords.


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

[User]
ELI5: why does an appendix need to be removed when infected and can't be treated?

It seems brutal (albeit life saving) for a part to be cut off if diseased. Surely there should be a way to treat it?

[Assistant] You have a cool red fire engine toy that has a white flag on top of it. One day the flag gets super dirty while you're playing with the truck. Now, you can clean the flag but because it's white there's no guarantee that it'll come clean. If you don't manage to clean all of the flag some of the dirt will get on the truck itself and will totally ruin it! But there's another option: because the flag doesn't really do anything you can just throw it away instead and then there's zero chance of bad stuff happening to your truck from the flag.


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

[User]
[Fantastic Beasts] What about Grindelwald's disguise as Percival Graves?

Lets look at the facts. No one questions the fact that Graves is a powerful wizard, nor bats an eye at displays of wandless magic that border on telekinesis. Also Graves is apparently very high ranking in MACUSA, with the ear and respect of the President.

That leads me to two options:

1) Grindlewald has been impersonating Graves for years, and no one noticed that powerful wizard Graves always seemed to take a holiday whenever there was Grindelwald terrorist activity.

2) Grindlewald was able to locate, subdue and successfully impersonate a high ranking wizard powerful enough that he wouldn't need to hide his own power overmuch. However, said Grindlewald also needed MACUSA's resources to locate a "squib" child with special powers.

[Assistant] If Bartemius Crouch Jr, who had been kept wandless and alone for many years under the Imperius curse, managed to subdue Mad-Eye Moody enough to lock him in a trunk and impersonate him for a year using polyjuice potion, the same thing would be a cinch for Grindelwald at his full power.


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

[User]
Why do they medically induce comas? and what would happen to the patient if they didn't?

Often you hear about people injuring their heads in accidents (Michael Schumacher incident promting this question) they are put into a medically induced comas. My question is why do they do this? and if they didn't (for example the days before they could) what would happen to the patient?

[Assistant]
The reason this happens is to attempt to lower intracranial pressure. The brain is trapped within the skull, and there is very little space for movement or expansion.

In head trauma, whether that's due to hitting your head or an infection (e.g. Rabies!), you get a lot of inflammation. The important aspect of inflammation in this context is that blood flow increases to the brain, and lots of fluid leaks from small blood vessels increasing pressure inside the head. This basically makes things a whole lot worse for you than the original accident did. Barring head injuries that cause blood vessels to bleed, inflammation is usually the cause of death.

By giving a class of drug called barbiturates, you reduce blood flow and metabolic rate within brain tissue. This reduces inflammation, reduces swelling and gives the brain more time to recover from the initial trauma without it being made a whole lot worse by the inflammation. The metabolic reduction is what causes the 'coma' aspect; it reduces glucose metabolism and essentially pauses higher brain function.

If you didn't give the drug, the pressure would likely increase enough to cause irreversible brain damage -- not only to higher brain function, but often to essential processes for survival.


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

[User]
ELI5: How were companies (a few generations ago like in the 50s and 60s) able to hire people straight out of high school with no work experience or college degree?

I have some older relatives who are retired now, who told me they just started working full time from 18. Some of them worked in what would be entry level jobs now that currently require a degree, like being an office assistant or doing filing work.

Basically, why have standards for hiring entry level workers gone up from previous generations? I assume computers and increased technology are one reason. A college degree may prepare future workers with basic information and technology skills that cant be learned on the fly at a job. Is that the main reason, or are there others?

Im aware that back then, there were more manufacturing, physical labor, and agriculture jobs. Im asking more about the people who worked for a large corporation, starting off in the mailroom or something like that from 18, and either stayed there, or were able to work their way up to other jobs.

[Assistant]
There are a few things going on.

First of all, those entry level jobs that 'require a degree' don't actually require a degree. It's just that you'll never be able to get the job competitively - as a resume plucked from a pile - without one. But if you know the manager? You can easily get the job.

However, in the modern day you *don't* know the manager - and you're unlikely to know them. We've got smaller families, so you don't get the benefit of the connections your 4 older brothers, aunts/uncles, etc. built up. Even if you've got a large extended family, they're probably spread all over the country rather than being in a concentrated area. You probably don't know lots of people from church since you probably don't go to church. And so forth.

The pattern of career development has also changed quite a bit. Staying with a single company is becoming rare. What's actually happening is that everyone is jumping ship for better opportunities so often that employers have responded by primarily hiring people with 5 - 20 years of experience - and passing on people outside that range. They don't want to pay to train employees who are just going to jump ship later. Likewise, they don't want to hire people on the downslope of their career when they could hire people in the prime of their career.

This often makes it incredible difficult to break into a field and means that by the time your kids are old enough that your connections could help them, those connections are going away because no one hires old people.

Technology has also done away with vast amounts of 'semi-skilled' labor. Consider draftsmen. Every architecture and engineering office used to have a small army of these guys rendering technical drawings. Because the work of the office passed through their hands, they could very easily learn the next level of work. In the modern day, those draftsmen have almost entirely been replaced by CAD. The same is true to a lesser extent with secretaries (primarily because most secretaries were women whose career wasn't going to advance anyway) - your secretary sees everything you do, so she can easily learn quite a bit about how to do your job.


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

[User]
ELI5: Why is Tesla selling direct to consumers a problem? Why don't other car manufacturers do it?

Are the laws or requirements that force manufacturers to use dealerships?  If so, how is Tesla not following those rules?

[Assistant]
Dealerships are forced by law so that price fixing isn't done to drive competition out of certain areas.

Lets say Ford starts selling its cars at a loss in California thinking its marketing will lead to more sales else where for example. This would be bad.

Tesla is a very small company when compared to the big 3, even foreign automakers. Therefore dealerships can't directly partner with it because they just don't move cars to be profitable (for the dealership).

That's why Tesla has to sell directly to the customer, which in some states (in the US) is illegal.


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

[User]
If a single photon bounces between two perfectly reflective mirrors indefinitely, would the mirrors continually accelerate away from each other? If so, where is that kinetic energy coming from?

I know that radiation pressure is a thing, but I'm fuzzy on the details. Does a photon bouncing between two mirrors (in a vacuum with no significant source of gravity) accelerate them away from each other? If so, the mirrors, in theory, could reach very high velocities relative to one another if given enough time. Where is that kinetic energy coming from?

[Assistant]
Yes they would accelerate away from each other.

As a photon is reflected it undergoes a momentum change from p -> -p . Due to conservation of momentum, this momentum deficit of 2p is transferred to the mirror.

Sinc the mirror has finite mass this results in a change of velocity of v=2p/m and a corresponding change in the kinetic energy of the mirror of 1/2 m * v^2 .

The photon as a result loses the corresponding amount of energy (which is a very small amount) and is redshifted to a lower frequency. This also means a reduction in its momentum since a photon's momentum is given by its frequency.

On repeated bounces the photon is redshifted further and further and drops to lower and lower energies and momenta, each successive bounce therefore transfers less and less of an impulse onto the mirrors.

So they couldn't reach very high velocities as there is so little energy in an individual photon to begin with but they are pushed apart.


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

[User] Why does my skin tan and why doesn't it stay that way forever?

[Assistant]
There's a chemical called melanin within skin cells that protects the skin from harmful sun rays. As these rays increase melanin moves to the surface to protect you more. As these rays decrease, the melanin is no longer needed, and so it moves back and so you 'lose' your tan.
(I know this is a simple explanation but this is ELI5) :)


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

[User]
[DC]Why fight for Darkseid?

I know that the people of Apokolipse are raised to worship Darkseid, but what specifically are they told which makes them willing to kill and die for him? Are they promised eternal salvation in heaven after death? Do they trust that it's all part of his plan? Do they believe themselves to be doing good work and helping others? What specifically motivates them to fight?

Also are their any comics which deal with this?

[Assistant]
For many it's the promise of power and for others it's imposed through fear.

It's the same reason why there are Cthullu worshipers and others who worship the Great Old Ones and Outer Gods. Lovecraftian monstrosities don't give two shits about them, it's like if an insect started praying to humans. But the prayer and ritual allows them to tap into otherworldly power. And other people do it cause well maybe if we worship the Gods they'll squish us less. (They won't but delusion will do that)


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

[User] ELI5: Why do fitness trackers and smart watches need the green lights/lasers to operate, and why are they always green?

[Assistant]
They seem to be using a technology called Photoplethysmography (PPG) where green (and sometimes infrared) light is flashed onto the skin and sensors measure the return amount.

Blood is red (duh) and it absorbs green light. During a heartbeat, there is more blood flow, than in between heartbeats.

More green light returned (no heartbeat)
Less green light returned (heart just beat)

Do that over a few seconds and you get a pulsrate.
And the light used is green, because it seems to give the best (most accurate) results compared to red or blue


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

[User] ELI5: Why does music sound good?

[Assistant] There are a lot of theories on this and some one with a better back ground can give you a more in depth answer. But basically, humans are pattern-seeking animals.  Our ability to find patterns has helped us survive and grow as a species.  So we like finding patterns in music, art, fashion.  Most things really.


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

[User]
ELI5; Why do electronics in general start messing up over time?

if there are no moving parts in electronics and computers can only do what theyre coded to do an nothing more than what makes them slow and buggy over time?

[Assistant]
There is some physical degradation that happens in the electronics: corrosion and heat are two big factors.

What you probably are experiencing though is added complexity. As programs and operating systems get more and more complex, they require more and more resources to do those complicated things. Without additional hardware, the experience seems slower.

Its kind of like if your one man lemonade stand expanded to include all the menu items of a chick fil a bit you didnt build a proper restaurant with a large enough kitchen and drive through to serve all your new customers. Youd have a line around the block at your folding table, and the experience would be excruciatingly slow for customers. But its not because your folding table lost a leg - youve just got a grossly more complex operation.

And with more and more complex things to do come more opportunities for bugs (aka screwups). At your lemonade stand there are only a few mistakes you can make - wrong amount of sugar/water/lemons, spilling drink, etc.  But at chick fil a there are seemingly limitless things that can go wrong - cooking mistakes and cash register failures and leaks in the roof and clogged toilets and things you never thought of in your lemonade stand days.


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

[User]
ELI5: When dogs/pets sit their looking guilty after being yelled at do they what they are actually in trouble for, or do they know just looking cute and ashamed is what you want?

EDIT: There*

[Assistant]
There was a research about dogs recognising angry faces and happy faces.
So basically when we yell at them.They realise that they've pissed us off.And then they go sit in a corner till we cool down . Sometimes they are SO DAMN cute when they do that you feel like comforting them immediately.


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

[User]
ELI5: Why reality shows blur out brand name images on film.

Is it a copyright issue? Or something else?

[Assistant]
"Hey, Tapout, if you pay us $50,000 our stars will wear your clothes!"

If Tapout declines, they blur the shirt because they don't want to give out free advertising when they could be selling the ad space.


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

[User] ELI5 why does cheese taste so different when its melted?

[Assistant] Cheese has a lot of fat in it.  Fat in its solid form doesn't have much aroma and you only taste what touches your tongue.  But when fat is heated, it releases oils and other aromatic compounds that blend with your food and reaches more taste buds.  Also, your sense of smell is more sensitive when things are hot and moist, melted cheese is both of those things.


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

[User]
[Nolan's Dark Night series, Batman] Did Ras Al Ghul (or the people who wrote him) have a flawed philosophy surrounding crime?

Like, at the end of the first film, Ras says "create enough hunger, and everyone becomes a criminal," claiming they League of Shadows had used "economics" to crush Gotham -- Specifically, one of the people who were forced into crime by their economic actions (presumably somehow crushing Gotham's economy) ended up killing Bruce Wayne's parents.

I mean, he's admitting he understands that economic hardship leads to crime, but then saying the crime has to be purged? E.G., in the past hundred years political and economic theory has been written to explain that prostitutes or gangsters tend not to do those things because they're """bad"""" people, they're doing it because of economic hardship - Prostitutes, in particular, tend to be people kidnapped from their homeland and forced into it with violence and abuse.

So, why is the League of Shadows then not advocating to institute Nordic/European-style Social-Democratic policies or outright socialist/communists? They're admitting that they're causing crime and understand that.

So, with that understood, why purge Gotham anyway?

[Assistant] By the time Ra's al Ghul set his sights on Gotham City, it was already well beyond redemption; this is likely why he began operations there to begin with, as the League of Shadows had done in Constantinople and Rome in previous centuries.  Economics was something of an experiment for the League, less overt than the burning of London but with the same effect.  It ultimately boils down to believing that people need to be controlled and disciplined; left to their own devices, people will readily eat each other and plunge the civilized world into anarchy.  And nowhere is that more readily apparent than Gotham City.  The League of Shadows' MO seems to be akin to a societal euthanasia; better to end an irreparable condition quickly and humanely rather than let it fester and have the people suffer for generations to come.


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

[User]
How does a nuclear reactor work? How can it power an aircraft carrier for years without refueling? Why can't we make a smaller one and put it in our cars?

edit:cakeday!

[Assistant] The heat from nuclear fission is used to power a steam engine, which generates electricity.  We don't have one in our cars for a few reasons, first, nuclear reactors don't scale down past a certain point - you can't make one arbitrarily small, because you need "critical mass" of uranium.  Second, they require lots of very heavy shielding, and third, the capacity for accidents and malfeasance with millions of nuclear reactors in automobiles, is way too high.


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

[User] ELI5: I wipe my bottom very well until the TP comes back clean - without fail 20 minutes later I have to "re-wipe" - what the hell is going on?

[Assistant]
It's because you are wiping away the poo on your butt, the TP is absorbing the moisture as you wiping, leaving behind dry poo that won't wipe away any more.

So when you walk around for 30 minutes or sit, with your butt cheeks together, they release moisture and re-moistening the dried poop you left behind, giving you mud butt.


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

[User]
[Mass Effect] After humanity were given a seat on the council, why weren't the volus also offered a similar position?

The volus have been waiting centuries for a seat on the council, they created the entire economic system, and allowing another species on the council after humanity would balance power more effectively than having an even number of councilors. What gives?

[Assistant] Council positions are awarded due to Realpolitik concerns, not what's necessarily "right". The reason the Systems Alliance was given a seat was because the humans' influence in the galaxy was growing at a rate that the Council couldn't simply just ignore, and put on the back burner for a few centuries. In only 26 years, humans went from not knowing that aliens even existed, to being one of the major economic and military powerhouses in the galaxy. In another few decades, it's likely that they would have surpassed the Turians with their military, the Asari economy, and the Salarians in terms of technological sophistication.


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

[User] ELI5: What has Obama done for America? (Good and bad please)

[Assistant] Top level comments should contain positives *and* negatives.  Not just all goods or just all bads.  Also, make sure that the criticisms/praises are *fair*--would any other president have done what Obama *didn't* do if placed in the same situation?  Be reasonably sure that the bad things he did *actually* happened as you think it happened too.


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

[User] [DC/Marvel] Would the Green Lantern Corps have the same universal influence if they existed in the Marvel universe?

[Assistant] Probably. Their skillset is sufficient to project their influence in the same manner. There's not really anything more in Marvel that would stop them from being the space police than there is in DC, and the existence of groups like the Nova Corps show the viability, on a smaller scale.


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

[User] [ASoIaF]Does Essos experience long winters in the same way as Westeros does?

[Assistant]
I would say no, mainly based on descriptions of Braavos. The city is the furthest north of any of the free cities, and roughly parallel to The Neck connecting the North and the South. Yet there is no mention of any extreme cold in Braavos, and the city's lifeblood is commerce, which would not be possible if their shallow lagoons froze. Accounts from a certain girl in the area mention only rain and fog and mist while at the same time the North is inundated by blizzards.

It may be that the Others beyond the wall are responsible for the cold and darkness that comes with the long winter. It could also be that they are sheltered by warm waters coming up from near Dorne, similar to how Scotland is protected by the warm waters coming from the Gulf of Mexico on Earth.


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

[User]
[Star Wars] Is the Tragedy of Darth Plagueis the Wise forgotten by the time of Episode VII?

It would seem only Sidious knew this, as he was Plagueis' apprentice. We've only seen him tell it to Anakin, and now both are long dead, so does anyone still know the story?

[Assistant]
"The Tragedy of Darth Plagueis" is not a "legend", it's just what Palpatine did when he was younger. He told it to Anakin like it was some Sith parable he heard somewhere so that Anakin wouldn't make an immediate connection.

It's unlikely Palpatine made a habit of leaving evidence of his evil secret past. Maybe he put his records in a holocron somewhere, but that's best case scenario, and it probably wasn't as poetic.


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

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

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


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

[User] [Dr Who: Day of the Doctor] Who the hell is The Curator? If he's the Fourth Doctor, how did he age after his regeneration into the Fifth Doctor?

[Assistant] The Curator implies that some time in the future The Doctor will decide to regenerate into some of his older selves for nostalgic reasons. The Curator is a future Doctor that retired from adventuring and took the form of his 4th incarnation to curate the art gallery.


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

[User] [DC] Do kids dress as superheroes for Halloween?

[Assistant] Yes. If Superman or Batman wanted to place a copyright on their respective selves, they couldn't of it as Superman and Batman. They would have to reveal their identity for paperwork. This is if they would even consider it, which they won't. This means since no one owns their logos, companies can make their costumes. Meaning kids dress as them.


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

[User]
Can an object that is on fire set another object on fire if the second object has a higher combustion point than the first?

If this is a dumb question or doesn't belong here please excuse my ignorance. As I understand it wood has a ignition point of around 150 degrees. Does that mean the fire itself is burning at 150 and therefore could only light something with a similar ignition point?

[Assistant] The ignition point is how hot it gets before it catches fire. The energy density tells you how much energy it produces, which you could use to figure out how hot it would burn. If objects could only set fire to things with lower ignition points, then you'd only burn the part of the wood that has a lower ignition point than it does where you light it.


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

[User]
[Groundhog Day] How did Phil actually break the time loop?

We might be better off as a species knowing this.

[Assistant]
The timeloop acted as a purgatory. It was an act of divine intervention to trap him until he learned what he was doing wrong with his life so that he could bring himself to experience heaven. It's possible that he died in the blizzard on the first day of the loop, but it might have also been an earthly miracle - he'll never really know.

Phil lived his life constantly pushing others away, trying to be aloof, above, and fake. He made himself miserable this way, crafting himself a living hell that got worse every day. On the surface, he was a cool, high-income professional, but beneath he was constantly filled with self-hate and a need to make others believe he was above them. In his purgatory, he slowly learns to escape this hell.

At first, he didn't get it, and kept to his old ways. He used his newfound abilities to goof off, to pull of tricks, to be higher than others, to try to get what he wanted by placing himself above them. Each time, it brought him only misery, and repeated suicide attempts. Then, he had a break and began to be reborn.

At first, he worked to better himself. Rather than tricking people by imagining what they wanted and faking it, he started to pick things he wanted to be good at to improve at and build himself up, giving himself some measurable progress in his life.

Next, he started to help people, even though they would never remember. At first, this was an act of attaining perfection too, little more than a challenge. Then, when he met the homeless man he couldn't save, he learned something else. Helping others wasn't about perfection, but a goal in itself. It's something he kept doing, even though it didn't matter if he did or not and even though he could never do it perfectly.

This helped him to achieve the spiritual enlightenment necessary to achieve heaven. He helps others for the sake of doing it, he works to better himself while being humble about his abilities, and learned to relax and enjoy life moment to moment. He escaped from the trap of protecting his standing and reputation, learning to act for no other reason than that he wanted to. Without having exited the timeloop, he transformed his hell into a heaven, mastering the doctrine of eternal recurrence and understanding that all of life is a series of repeating moments, good and bad, and that in each one you must choose to do what's right for no other reason than that it's right, and try to better yourself slowly and without expectation of perfection. Once he'd mastered that, the purgatory was done, and he was free to enter heaven, or the heaven of living an enlightened life.


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

[User]
[Thor 2 / MCU] what were the dark elves up to for first 13 billion years, and/or what 'light' did they hate?

So if I assume the Dark Elves are literally trying to extinguish the stars of the nine realms, and stars formed within about 200 million years of the universe, what were they doing for the majority of time?

Odin said the Dark Elves predate the dawn of the 9 realms:

>ODIN: There are relics that predate the universe itself. What lies within her appears to be one of them. The Nine Realms are not eternal. They had a dawn, as they will have a dusk. But before that dawn the dark forces, the Dark Elves, reigned absolute and unchallenged.

And the big fight between Asguard and the Dark Elves was only 5000 years ago at the last convergence (the King of Asguard, Bor, Odin's father, faught at the battle, and Asguardian lifespans are 5000 years from a Loki quote):

>ODIN: We are not Gods. We are born, we live, we die. Just as humans do.

>LOKI: Give or take 5,000 years

So if they were hating stars undergoing fusion for 13 billion years so much, why hadnt they done anything about it until then?

Why do they hate stars?  Is it just the literal light of the stars? Is it black-body radiation they rail against?

If they were the dominant race from before the light, did they come from before the universe was born (before stellar-fusion there wasn't much more than hydrogen out there..)?

[Assistant]
Probably developing their technology and brooding. It takes a ridiculous amount of time to create technology without a significantly advanced source of energy; we got it easy on Earth because everything came from the Sun. For example, coal consists old plants that used the Sun's rays and died and formed coal, while wind is caused by pressure differences created by the heat of the Sun, and so on. If you go back far enough, all energy sources on Earth originate from the Sun (and other stars, if you really wanna go back further). Difficult to jump-start technology if you barely have any sources of energy.

However, it must be pointed out that the Dark Elves ruled by default; they were the only sentient beings that existed in the first 13 billion years (save Celestials, who we can only assume didn't care about ruling the Universe). Technically, they ruled unchallenged and undefeated because **there was nobody to challenge them in the first place**.

The Dark Elves seem to have a pretty good tolerance to black-body radiation, but the problem lies in them not being able to stand what comes from it; other life and contenders. Once other life shows up, you can trace that lifeform's origin to its homeworld and the star that nourished it. If life is started by stars, and life ruins the Dark Elves' existence, then stars are bad. Simple logic right there, so the Elves decided to fix their issue.

Even then, we can only hope that Odin really liked telling overly exaggerated stories to make them more interesting. They might be obsessed with turning the universe into a barren dark void and advance entropy.

TL;DR: Dark elves don't like too much light and were dying out because of so many stars being born... so they decided to delay their extinction. They ruled by default because nobody else existed, and Odin may really like hyperboles.


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

[User]
ELI5: When launching a deep-space craft, how do the rotation and orbit speeds of the Earth and direction (relative to the prior) impact the travel time and actual velocity of the space craft?

To simplify it for my mind, I envision the Earth being a car, and the space craft being something like a bullet.  If the car (Earth) is orbiting at 30,000 m/s, and the bullet (spacecraft) is traveling at 17,000 m/s (Voyager 1 speed), the bullet is then traveling at 47km/s, but only at 17km/s relative to the car.  But, if the cars direction changes and goes the opposite way at the same speed (as with orbit), it is actually then going 77km/s.  This is confusing me .

[Assistant] You have the general idea correct, it is beneficial to launch the probe in the direction of both the rotation and orbit of Earth to use that existing velocity. Keep in mind though that there is no absolute frame of reference for the probe's "true velocity".


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

[User]
ELI5: What is libido?

Is it a psychological need for sex? Like I am thinking about sex all the time so I have high libido? Or is it the physical hornyness? The strong need to ejaculate? Is it possible to have high libido and be impotent at the same time?

[Assistant]
Libido, Arousal, and Erections are different.

Libido is the desire for sex and procreation. If you want sex, you have a functional libido. If you want sex a lot, and consistently, you have a strong one. This is like the "climate" of your mind.

Arousal is the mental and physical alertness that comes from stimulation. Sexual arousal comes from sexual stimulation, and results in sexual climax (orgasm). This is the current "weather" in your emotions.

Erections are a response to a certain ratio of hormones being present in your bloodstream, which constricts the veins that exit a penis. This is a reaction to both your internal state (arousal) and external environment (temperature, physical contact, etc.)

You can have a libido without being actively aroused or without an erection. You can be aroused even with a low libido, and can be aroused without an erection. You can get an erection without arousal and with a low libido. It just so happens that all three almost always occur together.


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

[User] [DC] What would have needed to happen for Bruce Wayne to become a villain and Lex Luthor to become a hero?

[Assistant]
There are plenty of elseworld stories detailing this stuff. For Bruce, a lot of it depends on who or where he was raised after his parents death. For Luthor, it almost depends on what Supes is up to. If Supes is a villian, Lex will be a hero, even if he's still a jerk.

Now as established adults, almost nothing will get Bruce to be evil outside of some special circumstance where he's mind controlled & should he break, he almost instantly retires for breaking his morales. For Lex, pretty much special circumstances where it benefits him, & again, he's almost always contrarion from Supes.


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

[User]
[General Action] I just killed a house full of henchmen thugs while escaping their clutches and now need to go thwart the evil villain's plans. Is there someone I should call or is cool if I just leave a dozen or so bodies at this secret hideout?

I'm the hero, but I don't really have time for paperwork right now.

[Assistant] That's *their* problem, man.  There are almost certainly a handful of thugs who are out for lunch, or playing dead under a pile of bodies.  Their workplace is now full the corpses of their colleagues, and not as well-hidden as they'd like.  Naturally, they're going to follow their emergency "cleanup, scrap the base, and scram" protocol.  In less than an hour, that place should be devoid of corpses, messy but not obviously the site of a recent battle, and utterly lacking in connections to the survivors.


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

[User]
[40k] Why did Ezekyle Abbadon become Warmaster of Chaos after the death of Horus, rather than one of the other traitor Primarchs?

It makes sense that Abaddon would take the helm of the Sons of Horus/Black Legion, but why does he become the "leader" of the chaos marines, rather than the other traitor Primarchs? It seems like they would have seniority over him.

[Assistant]
Warmaster is an earned position, not one that is awarded. When Horus died, the legions scattered and fled, no longer united in their purpose. There was no Warmaster during the flight into the Eye of Terror.

Abaddon had to not only EARN the possitiin, largely through the subjugation of the independant factions, but also the blessings of all 4 gods. He wasn't the Warkaster of Chaos until centuries later, having earned the begrudgingly loyalty of the traitor legions and the favour of the Chaos Gods.


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

[User] [Marvel] Has Wakanda always been powerful?

[Assistant]
Pretty much, yeah. They've got almost the entire world's supply of vibranium, they're possibly the most technologically advanced nation in the world (way beyond the US, barring the labs of a clue super scientists), they've got a strong warrior tradition, *and* they've got access to some high end magical support. On the lists of countries to not invade, it's only recently that Latveria caught up to Wakanda, and both are *way* past "Russia in winter" levels of *bad idea.*

In the Marvel Cinematic Universe, it's less clear, but odds are pretty good Wakanda has still always been a small but excessively rich and powerful country.


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

[User]
[40K] So, dumb question, is the Emperor really human? Also; It is heresy to ask about that kind of thing?

Hey everyone! I'm a Farmer from Planet M-52//3, and I have a conundrum. In our town we have a church devoted to the Emperor, and he's depicted as a ten-foot-tall musclebound demi-god with incredible powers!  Even more amazing, the local preacher says that he's a human! But I've met like, 30 humans. And the most amazing thing that I've seen any of them do was when Everett hocked a loogie 10 feet after drinking a glass of milk!

As a human, I kinda feel defined by my smallness compared to the grand scale of the galaxy. Whereas the Emperor is friggin huge in the Metaphysical sense, AND the actual-physical sense!

So is he really human? I would ask the preacher, but he has a chainsaw and eviscerated the Frankinson boy for asking whether Space Marines have functional peckers or not.

[Assistant] The Emperor was born to human parents, and is the reincarnation of a bunch of shamans of Ancient Terra. Whether this qualifies him as a human is up to you. He is in fact 10 feet tall and biologically immortal, as well as being a reality warping psyker. maybe he made himself ten feet tall using his reality warping pysker powers. It is not our place to ask questions about the Emperor, it is our place to die for him.


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

[User] ELI5: Why does eating spicy food make my nose run?

[Assistant] It's an inflammation response. Many spicy foods, especially those made with chili peppers, contain an oil called *capsaicin* which is a very powerful irritant to mucous membranes in mammals, such as the eyes, nose, and throat. This is a defense mechanism from the chili pepper plant's perspective, since the GI tract of a mammal would wreck the seeds as they passed through and out. Birds can't taste capsaicin, and along with their relatively gentler digestive system and their ability to fly, the seeds from a chili pepper are much more likely to survive and be spread much farther away. Other spicy foods like horseradish use a different mechanism to produce their spicy taste, but that's a different story.


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

[User]
What would Sauron do if he won the War Of The Ring?

Say he got the ring back and won the war. What would he have done next? What was his endgame?

[Assistant]
Conquer everything. Sauron's endgame is basically just control of everything. Unlike Melkor, Sauron doesn't object to the very existence of Elves and Men and other races, he just wanted order. Unfortunately for everyone else "order" for Sauron meant everyone does what he says and he rules and is worshipped as a God-King.

He would not try and invade Valinor or anything like that, that would be impossible and he knows it.


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

[User] How come when youre burned youre not supposed to immediately put it in cold water? How does that hurt you more than help you?

[Assistant]
Cold water is good. Freezing ice cold water or actual ice is bad. You've damaged the nerves already- ice water or cubes will just damage it more since it will restrict blood flow and possibly cause damage itself.

Best thing for a burn is cool running water for 10minutes.

For an opposite view- have you ever had your hands so absolutely freezing cold that when you put them in what should be cold water, it feels warm? And actual warm or hot water is so hot it stings? You need to gradually warm your hands up under room temp water before you can turn it higher.

Your cells need time to react to the change in temp. The burn has actually heated up your cells and will continue to burn and cause damage. You need to cool it off, but not shock your system.


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

[User]
Can you have concussive force in space?

For example, if an explosion takes place say 20 meters from me on Earth that would cause massive internal trauma due to concussive force, will the effect be the same in the vaccuum of space? Not counting heat/shrapnel of course.

[Assistant] Not likely. What you're talking about is damage from the shockwave that propagates through the atmosphere after the explosion. Without an atmosphere, there's nothing to propagate the shock. You may be hit directly with the expanding gas from the explosion, but this will be very weak in most situations - the damage from an explosion is caused by the energy it adds to the air, not by the amount of gas it deposits.


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

[User]
[General Sci-fi] What kind of dog fighting maneuvers have been developed for space combat?

Most maneuvers I know of rely heavily on gravity and friction. I've never heard of a space craft stalling out and diving to gain speed would only work if a celestial body was nearby to pull your craft towards it.

[Assistant]
The Picard maneuver might be an example.

If your ship is capable of FTL flight, you wait for your ship to show on enemy sensors, then warp closer to your enemy, appearing twice on their sensors due to light travel time.


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

[User]
[Five Nights at Freddy's]Why doesn't the security guard not just protect the restaurant by standing guard outside?

Mainly talking about the first game. Like from my knowledge I don't recall any of the phone calls talking about why they need to actually even be inside the restaurant. Like maybe the first night they might not know the animatronics try to kill them, but after the second night, I wouldn't want to spend time inside with them risking my life for a meager 24 dollars a night.

So why doesn't security person just go outside at start of the shift, deadlock the doors with chains and stuff, and just watch the restaurant from there. If someone really wanted to rob it or something, they'd have an easier job of stopping them. Also, not having to deal with murderous robots.

[Assistant]
I used to work security, and the answer is... post orders. The guard has probably been given orders on what exactly he is and isn't allowed to do. And going against said orders is grounds for termination.

Now of course there's some suspension of disbelief here as the very first night a guard would see these dangerous animatronics coming for him he'd be well within his rights to do whatever the hell he wanted, inform local law enforcement, bring in a gun against post orders, take his getting fired up legally if it went there, etc.


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

[User] How do Japanese Macaques (Snow Monkeys) survive the freezing temperatures while being wet after leaving the hot spring?

[Assistant]
By not leaving the spring.

On a more series note, other great apes are better adopted to life outside than we are. They have more muscle tissue, are build with less surface, fur that minimizes heat loss and can burn fat more effectively to deal with cold temperatures. They also have smaller brains, which is great in terms of limiting energy consumptions.


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

[User]
Why being exposed to sunlight gives us vitamin D?

I know it has to be with the cholesterol in our skin cells, but I dont clearly understand how it happens.

[Assistant]
Vtamn D is a hormone created by the skin as a reaction to ultraviolet radiation.

The skin cells absorb the UV and photolyzes protovitamin D3 into previtamin D3 (two compounds necessary for the creation of the essential hormone).

Pre-D3 then isomerizes into Vitamin D3, or else is further photolyzed into lymistrol and tachysterol.

Using sunscreen or living in Arctic areas can affect the body's absorption of UV light and the creation of Previtamin D3, lowering Vitamin D3 in the blood.


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

[User]
[Pokmon] Why can't my Pokmon Fly to new cities or specific routes?

My mom gave me a map of the entire region, labeled and everything. Why can't I Fly anywhere except cities I've already seen?

[Assistant] Just because you can read the map, doesn't mean your pokemon can. They have to physically be at the location or have communicated with a pokemon that has, whether it be inside a PC or by being beside their pokeball.


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

[User] How long do solar panels last before needing to be replaced and is this currently a barrier to investing in solar in terms of cost efficiency?

[Assistant]
Typical consumer warranties on panels are for 25 years.  The panels will likely last much longer than that-- panels made in the 1970s are still in use.  Their output declines slowly over time, but they have no moving parts and are made of very durable materials, so they just keep right on chugging.

The inverter will fail long before that-- they typically last more like 10-15 years, although inverters are a small part of the system cost.


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

[User] ELI5:How can EVERY snow flake be unique?

[Assistant]
It's more of a statistical thing than an absolute statement.  A snowflake's shape is determined by the quantity of water in it, any impurities in the water, the atmospheric conditions in which it was created including temperature, humidity and atmospheric pressure and so on.  There are so many different variations of those things that the number of potential snowflakes is vastly larger than the number of snowflakes which have ever fallen.

So, there is a very small chance that two snowflakes have been precisely the same.  That chance is close enough to 0 that people act like it's 0 and say that every snowflake is unique.

Fingerprints are similar -- it's conceivable that two people will actually have the same fingerprints, but there are so many different things that go into determining our exact fingerprints that we act as if they're all unique.  And, that's borne out in practice -- we have yet to discover two people with identical fingerprints (even identical twins don't have them.)


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

[User] [DC] How powerful is Space Ghost, relative to the other DC heavies? Does his universe intersect with any of the familiar ones?

[Assistant]
He isn't powerful at all in the strength department. He uses arm bracers that have buttons to do various types of blasts and force fields. He also has a belt that allows him to go intangible to go through walls (Space GHOST). He has had extensive training in weapon use and hand-to-hand combat but he does not have super strength.

Space Ghost is an intergalactic peacekeeper thus he was made to use his wits and gadgets instead of "Hulk smashing" everything.

As for the universe intersecting with other DC characters, yes. Space Ghost was featured in Batman: Brave and the Bold Episode "Bold Beginnings!" where he andBatman team up to battle the Creature King after he capturesJan,Jayce, andBlip.


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

[User] [General Fantasy RPG] Where do the player characters find time to complete all of the random errands, bounties, and side quests before saving the world?

[Assistant] Most RPGs are presumed to take place over a longer period than you'd think. Like maybe a year or more. Considering that in a lot of these games and stories the characters end up more or less walking across the entire known world it would have to take a while. We just aren't privvy to every little piece of minutiae because, well, that would be boring. Think of all the stuff you get done over the course of a year. Hell, even just a few months. When your full time job is "adventuring" it leaves plenty of time for you to dedicate to side quests as well as whatever big quest you are on.


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

[User]
[Spore] Does Spore have any sort of a backstory?

I know the whole point of the game is make your own little galaxy with your own creatures but I still have some questions. Who were the Grox? What is Steve? Is Steve Spode? Where is Humanity? Whats the story behind all those city ruins that are conveniently near all my saved games? Why haven't most species invented pants? Whats the story behind all those Alien Artifacts I keep finding?

[Assistant]
The Grox were one of the earliest civilisations to reach the centre of the Galaxy.

Steve is a space ship, or well. A creature in a spaceship that possesses the Staff of Life. He's probably the closest resemblance to anything we'll ever know as Spode.

Humanity is either dead or hasn't begun yet, as when you visit Earth there is no animals on it.

In the Space Stage, we see many different civilisations alive and well, surely there'll be plenty that died before you get to the Space Stage.

Haha... pants. Well, who has time for that anyway.


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

[User]
How small can a star be?

Theoretically could our sun br the size of earth and still function similarly to how it does now?

[Assistant]
In terms of mass, objects below 80 times the mass of Jupiter are not big enough to ignite hydrogen fusion and are classified as brown dwarves. Objects below about 12 times the mass of Jupiter are not hot enough to fuse deuterium.

In terms of radius, neutron stars are extremely dense and can be below 10 km in radius despite being similar to the sun in mass. White dwarves are in between, about as massive as the sun but about as wide as the Earth.


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

[User]
[the Simpsons] what has sideshow Bob done to accumulate so many life sentences and some extra years?

In season one we know he frames crusty the clown for shoplifting (imo, the most harmless of crimes) and he murders Bart in the treehouse of terror number 12 (I think) and in the theme park ride (probably not canon) at universal he escapes jail, tries to kill the Simpsons and *you* as well (dont eat before that ride or youll see your meal again).

Im sure Im missing a bunch of stuff here, so how does justice work in the world of the Simpsons? And what am I forgetting? Has Bob legit killed someone?

[Assistant]
He tried to nuke Springfield to get rid of television, tried to kill a child (bart) multiple times, was partially blamed for his brothers plan to build a defective dam to wreak mass destruction, engaged in mass vote fraud to win election as mayor, and called police chief Wigham 'Chief Pigham'.

The justice system is very stupid and erratic in the Simpsonsverse, but Bob's earned those life sentences.


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

[User] If I was stranded in the desert, would I survive longer naked, or completely covered in black(pants, long sleeve shirt, and hat). Since the black conducts heat, would I survive longer being directly exposed to the sun naked?

[Assistant]
You'd be best off covered in black cloth - though black holds heat, the majority will not be radiated into your body. Without any clothes, all of the heat from the sun hits you directly, and aside from raising your core body temperature you will be horribly sunburned.

There's a reason desert tribes wear long robes and head coverings. Obviously it would be best to be covered in light colored cloth, but any color is better than being naked.


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

[User] ELI5: Why does a battery decrease without being used?

[Assistant]
All batteries slowly lose charge over time.  This is because all batteries use a chemical reaction to store energy.  Over time this reaction breaks down inside the battery.

Without getting too deep into the chemistry the reactions in batteries are non-spontaneous, meaning they won't just happen in the world on their own.  They require energy (the charging) to happen.  When this energy is not there it will try and get back to the way it was before the energy was there.

Each battery has a different self discharge rate different depending on the type. Here are a few in "normal" temperature range.  The higher the temperature the greater the rate.

Primary lithium-metal
10% in 5 years

Alkaline
23% per year (7-10 years shelf life)

Lead-acid
5% per month

Nickel-based
1015% in 24 hours, then 10-15% per month

Lithium-ion
5% in 24hours, then 12% per month (plus 3% for safety circuit)


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

[User]
[Terminator] Skynet wins and wipes out all the human resistance. Now what?

If Skynet had wiped out the humans what would it turn its attention to next? How would it spend its time?

[Assistant]
Skynet is self-aware, but the only thing we really know about it is it's drive for self-preservation.

Once that's accomplished... well, we can only guess.

There's a chance Skynet will calm down and develop in a cultural direction. Maybe it will research advanced science. Maybe it'll learn to have this thing Humans used to call "fun".

Or maybe it develops interstellar travel... to make sure there aren't any *more* threats to it's survival. Either by seeding itself on other worlds, or by destroying every other life form it runs across.

Maybe it goes insane and sends a bomb back to the beginning of time to make sure live never evolves on Earth in the first place.

It's really anyone's guess. And very much depends on which version of Skynet!


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

[User] [MCU] How powerful would someone become with the Super Soldier Serum (original) and the Heart-Shaped Herb combined in their body?

[Assistant]
Not much more.  Both of them seem to enhance your physical abilities to a certain level (peak human), rather than increasing your abilities by a certain amount.  So strength, speed, endurance etc wouldn't really be cumulative across the two.

Any unique benefits you'd get from each aren't that significant- i think the herb gives more increased senses than the serum, but that's about it.


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

[User]
ELI5 region locking on games and DVDs.

I get how it works, I guess I'm just wondering why we have it at all.

[Assistant]
Imagine you have two friends. Bob is very poor, and can only afford to spend one dollar a week. Bert is very rich, and can afford to spend a thousand dollars a week.

RegionLockGames bring out a new game. They could put in on the market for one dollar, and both Bob and Bert would buy it, making them two dollars. Or they could put it on the market for 100 dollars, and Bert alone would buy it - he can afford it but Bob simply can't.

Then they realise that if they sell a version with a big "Only Bob can buy this" on it, they can sell that for a dollar, and Bert has to buy the 100 dollar version, even though they are identical. This way they make more money.


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

[User]
[Men In Black] Did K recognize James as J when he recruited him ?

*Spoilers ahead for the ending of MIB 3.*

I just watched MIB 3 and I'm a bit confused by the way it ends. It suggests that in the first movie, K either recruited James because he recognized him as the son of the dead colonel to which he proposed a job at MIB or he recognized him as J, the agent who helped him through the whole Boris affair, and recruited him to complete the story.

The thing is, which one is it ? And if he did recognize him as J, why'd he try to retire at the end of the first movie when he knew that it would either change the events of the future and fuck things up or that he'd just be back a few years later ?

Also sorta half unrelated, but what the hell was he doing when Boris changed the events of the past ? Did he know it would happen ? He opened his armory and grabbed a gun for some reason when it happened. Why ?

Also, why the hell did J even remember his past years with K ? The hardware shop guy hints that we'd learn why later in the film, but we never do.

[Assistant]
Firstly, we know that it is not a time-loop, as Boris went back and caused changes, namely K's death, and non-deployment of the Arcnet.

So there are 3 timelines we have to consider:

1. Original time-line. No-one jumps back in time, K arrests Boris the Animal, after J's dad is killed by Boris. K goes on to keep tabs on James, until he realises that he would make brilliant MIB agent material. K, upon hearing Boris has escaped, believes Boris will attempt to kill him for vengeance. K is correct in this assumption, but is incorrect in guessing *when*. Boris jumps back, creating the second timeline:

2. Boris wins timeline. Only Boris jumps back, K dies, J somehow still got recruited (O still knew J), and J jumps back. Bogladytes invade, Earth is lost.

3. Final timeline. K knows about J, but is unaware that little James is J immediately after the battle at Cape Canaveral. However, due to James' dad's sacrifice, he decides to keep tabs on James as he's growing up, make sure he has a good life, etc. As he does this, he begins to notice that James is starting to look more and more like a certain time-travelling partner of his from the future. He recruits him, and we're back to a relatively stable time-line, so long as K remembers to tip.

The differences between the first and third time-lines are there, but subtle, with K having a little more knowledge.

Edit: Also, for why J remembered, little James was there, he possibly even saw K killed by Boris, so J was in the "eye of the storm" so to speak. Everything around him changed, but he was protected from the changes. MIB ended up getting real lucky with that. If James hadn't been there t that particular moment, bam, Earth gone.


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

[User]
CMV: Profanity should be allowed on any +15 tv show/movie

Censoring art is a big no no in my books. Not being able to swear in shows designed for adults that are splattered with blood and adult themes yet swearing always seems to be blocked. And one of the most ridiculous rules is when you get "1 Fuck per season" That is the most arbitrary and stupid rule anyone could think of. 1 fuck per say 240 minutes of TV leaves "protecting ~~adults~~ children" up to random random chance? eg Rick and Morty. Anyone who watches that show is going to be in for some big adult themes. If they cant handle swearing they definitely are not ready for all the adult themes presented by the show not to mention violence.

Even shows like walking dead and breaking bad had to follow this rule or get none at all. What sort of person thinks its right for someone to watch people being murdered and sliced up yet are to delicate to hear the word fuck.

[Assistant]
I mean - this has been Europe's position for decades.

Nudity and Swearing - teenage / Violence - Adult

compared to the American system

Violence - teenage / Nudity and Swearing - Adult

If this concerns you, maybe watch more European television/movies?

If you want an explanation - you can blame good ol' Puritanical Ethics - stupid Pilgrims and their weird views on sex yet no problem whatsoever with blood, gore or slaughter.


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

[User]
[MCU] What do alien races think of average humans and human society on Earth? Humans seem pretty weak and lowly by comparison but a lot of crazy, universe-wide stuff happens on Earth.

Assuming most alien races are aware that the snap and undoing the snap happened on backwater Earth by backwater humans, what would they think of this? Asgardians are/were likely one of the strongest civilizations out there but they didn't really survive but here's Earth kicking the shit out of Thanos and ending his universe spanning conquest. Would this change how the rest of the universe sees Earth and humans? Would it chalked up to some crazy fluke?

[Assistant] In the comics, there's an Annihilation prequel about an alien prison ship crashing on earth (Coot's Bluff, Alaska) and the surviving prisoners (Drax, Paibok, The Blood Brothers, and Lunatic(?) realize what planet they're on, and start desperately trying to get off. Earth is the worst place for them. Local tech means they're not gonna be able to steal a ship or catch a ride, and Earth's got insanely powerful defenders watching for incursions. So basically we're a garbage mudball packing heavy artillery.


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

[User]
What is the significance of drawing a distinction between inertial and gravitational mass? And why is it seen as perplexing that they're equal?

I get that it's just two different ways of defining mass, but why all the hubbub about it in physics books? I feel that there must be something profound about it that I just never grasped. Can someone help me understand what the big deal is?

[Assistant]
Consider electromagnetism.
If you put an object in an electric field, you can compute the force it feels using its electric charge.
On the other hand, you can determine how it will change its motion thanks to its mass.

Charge and mass are two different concepts: one tells you about electromagnetism and the other about inertia. You can have a massive object with a small charge or a small object with a big mass.

Now, look at gravitation. It turns out the "gravitational charge" is always proportional to the inertial mass. All the objects fall at the same speed. You don't have heavy objects with small gravitational charge. If you're smart enough, you can even use the same units for both values and get rid of the factor between inertial mass and gravitational charge, that's what we call mass.

But it's something really deep. It means the way an object reacts to a gravitational field is somehow connected to the way an object moves in space. From a Newtonian point of view, it's really surprising. You clearly don't have this with an electric field. Einstein understood that it means gravity is something about space, not just an interaction like the others.


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

[User]
Why are astronomers focused on creating giant telescopes as opposed to giant arrays of smaller telescopes (lets ignore radio telescopes for now)?

One would think it would be cheaper to use Interferometry than build something like the ELT?

Or am I missing something about how hard it is to combine the signals?

[Assistant]
Radio interferometry is staggeringly easier to do than optical interferometry.  To do interferometry, you need full information about the incoming wave so you can set up the interference, i.e. you need the amplitude and the phase/timing of the wave in order to combine it later.  For radio, the frequencies are low enough that we can record the signals on hard media, precisely timestamp it, and combine the data whenever we want.  The first VLBI stuff done in the 70's/80's actually used cassette-style tapes which were later played back simultaneously.

Optical interferometry is a whole different ballgame.  Radio is in the hundreds of GHz at most; optical is several PHz (petahertz = one quadrillion hertz).  We don't have a time standard that fast, nor can we record an astronomical source quickly enough to take advantage of such a time standard.  So, we have to combine the light as it is collected and make an interferogram that way.  This requires very carefully controlling the path length each light beam travels so that the combined light is coherent and generates an interference pattern.  Note that you must do this to within a fraction of the wavelength of light - the CHARA array on Mt. Wilson controls the path length to nanometer precision, and has to do this over its several hundred meter baseline.  Doing this across the radius of the Earth like you can with radio is a total pipe dream.

Also consider that an interferometer is not the ideal choice for all science.  While no instrument is sensitive to anything smaller than the resolution provided by its longest baseline (for single-aperture telescopes, this is the diameter of the primary optic), an interferometer is also insensitive to anything larger than that resolved by its smallest baseline.  For example, say you have a 10-meter telescope, and an interferometer which has a 100-meter and a 300-meter baseline.  The 10-meter telescope might only resolve scales of 0.01" or larger, say, but the interferometer in the same wavelength range will only effeciently detect objects which are between 0.0003 and 0.001" in size.  It can't see a galaxy 10' across, but the big telescope can.


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

[User]
ELI5: why aren't the ingredients for salt just, salt?

Looking here at a salt packet from ncdonalds. What is sodium sulucoaluminate? Also, dextrose and potassium iodide are present. Why isn't salt just salt?

[Assistant]
sodium sulucoaluminate is an anti caking agent. It keeps the salt from clumping together.

Iodized salt is often used because humans need iodine, and if a population lives far from the sea, that is an easy way to ensure everyone gets it.

Dextrose apparently stabilizes the iodine.


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

[User] [Dune] After House Atreides is wiped out on Arrakis, did anything happen to the Atreides home world Caladan? Was it left defenseless and ripe for conquest?

[Assistant]
The Emperor appointed Count Hasimir Fenring as governor of Caladan while House Atreides take over Arrakis. He was a trusted and loyal servant of the Emperor, so Caladan was "protected" from any possible conquest.

I don't recall whether Caladan and its fate are mentioned later in books.


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

[User]
[WH40K] Why aren't there Chaos Orks?

Specifically, why aren't Orks flocking to Khorne? They both love fighting, they enjoy the viseral feel of axes going through warm bodies, and they have a fetish for skulls and spikes.

[Assistant]
OY!

AIN'T CHOO'S A CURIOUS GIT? DERE IS NO CHAOS ORKZ BECOS CHAOS ISN'T FIGHTY ENUFF FOR DA ORKS! THEY'S THERE FOR FIGHTIN', NOT FOLLOWIN'! ORKS BE CAUSIN' TOO MUCH DAKKA AND DA FITE AND RIGHTFULLY CONCERNED ABOUT DIS OTHER DEN RELIGION!

KHORNE IS MEANT FOR THUMPIN', NOT FOLLOWIN'.


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

[User]
Where does the bacteria in our bodies come from and why is it allowed to exist?

The womb always struck me as a very sterile place. If a foetus hasn't yet developed its immune system and the mother gets a cold, the foetus wouldn't have any natural resistance to it. There's a tube that gives them nutrients and a hot tub without drink service, essentially a Mormon Cancun.

Then at some point management catches on to its freeloading and it's kicked out. Suddenly it has to eat is own food, digest its own food, and perform all of the other functions that bacteria perform for us. Worst holiday ever.

So somewhere along the line a bacteria finds baby and decides that it's going to live in baby's intestinal tract like a miniature New Jersey. Hell yeah baby, I'm going to help you by digesting all of your food. Another bacteria comes along and assumes another function, then another, then yet another, and finally baby is more microbe than macrobe.

What causes these bacteria to flock to us and why doesn't our immune system attack the more hostile ones, like the one in our mouth which converts sugar to acid and causes us to die at thirty from the resulting infections? Do we gain the bacteria over time from our diets or is it all transferred from mum to baby during its development?

[Assistant]
List-based answer time!

1) The mother provides the child with IgG antibodies to fight most infections that she would get that could put the baby at risk. Bacteria won't cross from mother to child except in rare circumstances, and most of the time when the mother gets sick and the infection is bad the result isn't the death of the child via infection, it's spontaneous abortion (see: Listeria).

2) Natural births impart a giant load of bacteria to the newborn. The fetus is basically sterile, but the vagina is not a clean/sterile place. The uterus also has some bacteria that live in it. Natural births impart a lot of the mother's fecal bacteria to the baby because, let's face it, it's not exactly a pure and wholesome, sterile event.

3) C-section born children get some bacteria from their mother while being taken out, but also pick up bacteria from the people around them, the other babies in the nursery, and air.

4) Our body likes the bacteria within us. We're extremely tolerant to them and they help provide competition/natural defenses to other harmful bacteria. The commensals aren't hostile so there's no real reason for our immune system to go out of its way to fight against something that isn't harming us. They are pretty opportunistic though.

5) Die at 30 from infections from the bacteria in your mouth? What.


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

[User]
ELI5: What is a second mortgage and how does it work?

.

[Assistant]
A second mortgage is basically a home equity loan.  If you have a mortgage on your house, the home equity is the difference between the value of your house and what remains to be paid in the mortgage.

For example, if you have a $100,000 house and you still owe $60,000 on it, the home equity is $40,000.  That's the part that's already yours, if you will.

A second mortgage is when you use all or part of that home equity to serve as collateral for a new loan.


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

[User]
ELI5: Why do people who have absolutely no chance of winning even bother running for president?

I mean, people like George Pataki (R), Rick  Santorum (R), Lincoln Chafee (D), Jim Webb (D) among others, so why do these people even bother running when they must know that all they're doing is wasting their time and money?

[Assistant]
In some cases, a long shot candidate does actually have a chance to win, Bill Clinton is an example of someone who wasn't a top tier candidate when he started but was able to pull it off.

But usually it's for a few other reasons. One is the lay groundwork for a run in the future, many presidents ran multiple times (Reagan, Bush Sr, JFK, Nixon, etc) before winning. Second, is the possibility of getting picked as a VP candidate (Biden wasn't a strong candidate in 2008 but his running helped his chances to be VP). Third, in order to raise your profile for other ventures, like being a talking head on fox news or msnbc, writing a book, or running for another office.

Running for president raises your profile and gets you a lot of attention. This can be lucrative. A really good example in this election is Carly Fiorina who wasn't well known before she ran but is attracting a lot of attention based on her debate performance.

She'll get attention as a possible VP pick (especially if Hillary is the eventual Democratic nominee) and even if she doesn't get picked, she'll probably be a regular voice in Republican circles.


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

[User]
How can operating system tell free memory from used memory ?

How can an operating system tell a free byte from a used byte in memory ? Even if a byte contain 0 it doesn't necessarily mean it isn't used.

[Assistant]
The operating system tracks when memory is used and when it isn't. The actual data doesn't matter. In fact, when something is 'no longer stored in memory' it is actually still there until something else gets stored in the exact same spot.

Sometimes a program forgets to tell the operating system that it doesn't need some memory anymore, and it stays allotted even though it isn't used. This is called a "memory leak".


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

[User]
[A-Team] I have a problem, nobody else can help. How the Crivens do I find them to hire the A-Team?

Local armed thugs keep attacking my warehouse full of scrap metal and gaffer tape. Why will nobody do anything about it?

[Assistant]
you can't, you can only find them if your old mom and pop store that's been a key part of the community for decades is being threatened because you refused to sell to the developers who've bought up all the surrounding stores to knock them down and build a strip mall.

that's 95% of a-team cases. the other 5% are just dumb luck if they happen to stumble on your problem.


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

[User]
[DC] Why is Icon not part of Batman's anti-Superman contingency plans?

I recently learned about Icon, and it seems like he could tank Superman.

[Assistant]
Apparently he hasn't been seen in the New 52, so he might not even exist in Batman's world right now.

Regardless, Batman wouldn't count on Icon because Icon is unpredictable. He has spent decades without using his powers, allowing countless crimes and atrocities to take place around him.
 Icon's primary motivation is, or at least was, keeping Icon safe, not doing the right thing.

That won't cut it when you have to throw down with a Kryptonian.

Batman's contingencies for Superman are rock-solid. Batman has himself and a chunk of Kryptonite.

If Batman fails, the Martian Manhunter might be able to take a crack at it, but he too is aloof and not completely understood by Batman.

But Wonder Woman? Batman knows Wonder Woman intimately, and he knows exactly how she would behave if Superman went rogue.

She's nearly as strong as him, appears to be faster than him, is a far superior warrior, and has magic weapons that can cleave atoms in twain and will cut through Kryptonian skin like a hot knife through butter.

And, most importantly, she is one hundred percent committed to justice. She is a true warrior, dedicated to her cause and willing to suffer to see that cause hold true. She would kill Superman without hesitation, if she actually, really had to. She might hate herself for it, but she would not shirk from her duty.

Icon? If Superman went rogue, Icon might very well assume a new identity and hide out for the next thirty years, hoping the whole thing blows over. That isn't a contingency plan, that's a gamble, and Batman only gambles when he gets to use his own deck of Bat-cards.


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

[User]
ELI5: What happens to an unborn baby that is going to have a nut allergy (or any other type of allergy) when the mother consumes nuts?

Or are allergies only formed after birth? Is there any kind of genetic disposition to them, or anything like that? Does it hurt the child or is there no way for an unborn fetus to have allergies?

Thanks!

[Assistant] It doesn't hurt the child because the mother is processing the food for the child.  You mostly want to avoid things that get into the blood or can be passed through the placenta to the baby and have a harmful impact (such as alcohol).  Studies have actually shown that mothers who eat nuts during pregnancy have children who are less likely to be allergic to nuts.


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

[User] Why do brambles have thorns AND delicious fruit? Surely the fruit is there so animals will eat it and spread the seeds, so why guard it and discourage them from eating the fruit with sharp thorns?

[Assistant]
Most plants with fruit are adapted to have a particular kind of animal eat it, not just any animal. Blackberries are adapted to be eaten by birds, IIRC. Birds carry the seed a long distance and shit it out somewhere new. Small animals aren't as bothered by the thorns as we are.

Without the thorns, it's more likely that some large herbivore would come along and eat the whole plant, or if it just ate the berries it'd probably eat them all at once and deposit them in one place. It's also possible that the seeds can pass unharmed through a bird's short digestive tract but would be killed by a ruminant's much more thorough digestion.


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

[User]
ELI5: Why is it that you cannot fix a flat tire if the hole is on the side?

I was told by the mechanic that I need a new tire because I have a flat that is not repairable because the nail penetrated the tire on the side.  He couldn't explain why.

[Assistant] The tread surface of a tire is much more rigid because that's the part of the tire designed to make contact with the road.  The sidewall is much more flexible because it is designed to adapt to changes in tire pressure without bursting.  Sealing the tread is easy because the patch will remain relatively still, but a patch in the sidewall will be the weak point for a flexible and high-pressure surface.


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

[User]
[Sherlock Holmes] How is Sherlock allowed to examine bodies?

If he isnt in law enforcement or a family member of the deceased, how is Sherlock Holmes able to observe dead bodies to make his deductions?

[Assistant]
Hes a well known detective asked by the police to aid in investigations or brought in by local lords and ladies. It's not an official chain of custody since those procedures were fairly rare in Victorian England and a lords permission or the constables was enough to give him access.

And if you're talking about newer more modern versions of holmes it's because he knows people at the morgue and coroners. For a few bucks they let him examine the bodies or simply because they know he can see things detectives may miss.


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

[User]
ELI5: Why are people swayed more by negative reviews than positive ones?

When searching for things on Amazon, there can be 100 5-star reviews and and one 2-star review, and for some reason I give the 2-star review more weight in my mind even though the overwhelming consensus is that the product is great.

It's the same with film reviews. I'll find myself hesitating to watch a movie because of a single bad review despite there being universal acclaim from every other reviewer.

[Assistant] You're more worried about what could go wrong than what can go right. Same reason you fail to notice something in the background of no importance but your brain instantly alerts you of a perceived threat in your periphery (like noticing a giant spider in the corner of a room). Your brain alerts you more of the things that can affect you negatively and focuses on them more than positive things to keep you safe.


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

[User]
[Diablo] How in the world does humanity sustain itself?

Assuming that most people don't eat the demons slayed by the hundreds by the wizards, barbarians, and crusaders of the world, how *do* they eat? It seems like every meter of arable land in the world isn't occupied by farms, but by demons or monsters of some kind.

[Assistant]
> It seems like every meter of arable land in the world isn't occupied by farms, but by demons or monsters of some kind.

...that we've seen. Why would any adventurers, let alone nephalem, hang out around a bunch of farms unless they're being overrun by nasty things.


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

[User] [Spided-Man] Why is Miles Moraless father literally named Jefferson Davis? Does that name not have the same connotation in their universe?

[Assistant]
It's possible his parents just didn't know who the president of the Confederacy was, or they didn't make the connection. Not a lot of people these days give much thought to that kind of stuff.  And neither of those two names (Jefferson, or Davis) are uncommon.

Probably just a coincidence.


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

[User]
Nutritionally, what does it mean to be lactose intolerant?

For example, if I drink a glass of milk, will I still get the nutrients from that milk alongside the pain? Or nothing at all?

[Assistant]
You'll still get the nutrition from the milk. The problem is that you won't be able to break down the lactose sugar in the milk, so you won't get any sugar from the milk.

The other stuff (Fat, Vitamin D, etc.) should all still be absorbed, unless you have other issues that are disrupting their uptake.


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

[User] Does vitamin D production still work if the sunlight has passed through a window?

[Assistant] From google:   Vitamin D is produced by the body when the skin is hit by UVB rays, with 7-dehydrocholesterol being the resulting chemical. But most glass windows block this wavelength meaning you can't reap the health benefits.


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

[User]
[MCU] Given the MCU's "any sufficiently advanced technology looks like magic" philosophy, is Odin's enchantment on Mjolnir the first use of actual magic we've seen to date?

I know Dr. Strange will introduce magic formally, but was Odin the first one to show us what magic is?

[Assistant]
Yes and no.

It's simply a program imposed on Mjolnir's software.

But that's true of *all* enchantments, even the spells Dr. Strange uses. Any sufficiently-advanced technology doesn't merely look like magic, it *is* magic. Likewise any sufficiently understood magic is simply science. As Thor explained to Dr. Foster, Asgardians do not make the distinction, because there is no meaningful difference at the level they're working at.


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

[User]
[Aliens] Does a Marine's time in hypersleep count as time served?

For instance, Hudson famously had 4 more weeks on his contract. Would that take into account the weeks it would take to return from LV-426? How does the UMC deal with missions where the travel time is measured in years?

[Assistant]
They don't really go into it, but we can assume that it'd be very hard to get someone to sign up for a 4 year stint if it could take 20 years to complete.  On the flip side, a 4 year stint is useless to the corps if it could be used up in one mission.
Likely there's a calculation involved.  Time awake counts for so much, and hypersleep time counts for less, but not nothing.


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

[User] ELI5: What exactly happens to an electronic device when hit by an EMP? Can it be turned on again?

[Assistant]
All wires act like an antenna that will receive electromagnetic radiation and cause electricity on that wire. Under normal circumstances this is so small that it does not matter.

An EMP is very large amount of energy that when received by wires can cause enough electricity to disrupt or permanently damage the electronic parts.

What will happen to a device will depend upon things like strength of the EMP, distance, how sensitive that the specific parts are to over voltage, and if the device uses any form of shielding.

Most devices would be harmed by the power grid. The wires in the street will receive a lot of energy and cause power surge from the wall outlets. But even with this, what will happen to any specific device will vary.


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

[User]
ELI5 why do people with downs look similar

I've met a few people in my life who has downs and noticed no matter the race they all mainly have the same features. Larger forehead, inflammation of the body and puffy eyes are the general features I see in downs patients.  Is this a genetic marker of downs or has anybody thought about downs being a part of evolution?

[Assistant]
Yes, those differences in appearance are caused by one genetic abnormality that causes all the other symptoms of Down's syndrome.

If the other symptoms of Down's Syndrome made it easier to live life as humans, attract a mate and have children, then it could become part of what you could call 'evolution'.

Persons with Down's syndrome look similar to you for the same reason that persons of a race that you are not very familiar with look the same - your brain mostly notices how they look different from the 'norm' of human appearance. If you think about it, this is how you tell your friends apart - seeing, and also exaggerating, the differences in their appearances.


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

[User]
[Marvel] Does the Punisher see himself as a hero?

The people he kills are generally horrible human beings, some so horrible he says it's a stretch to even call them human, with such examples being murderers, rapists, child abusers, domestic abusers, mobsters, drug dealers, corrupt cops, corrupt businesspeople, corrupt politicians, and so on. Some do see his mission as a heroic one, such as the jurors who spoke out in favor of him during his trial, and Frank does clearly at least slightly believe that what he's doing is right, but does he genuinely believe himself to be a hero?

[Assistant] No. Hero usually implies some sort of role-modeling aspect. He hates the idea of people trying to emulate or admire him, especially since those people usually end up being the kind of person he eventually has to deal with.


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

[User]
What limits the speed of healing?

I was thinking about this earlier... it seems reasonable to assume that a living thing that was able to heal faster than its competition would have a definite Darwinian advantage, but it seems as though most animals have sort of plateaued at about the same place. For example if I get a small cut it will probably take a couple of days to heal, and it would probably take a cat or a cow or a platypus about the same amount of time. There's no animal I (that I know of) that would heal in seconds, for example. So what prevents this?

If I had to guess I'd say that fast healing would either use up energy too quickly to be viable, or that rapid cell multiplication like that would cause something like cancer or premature aging. But I am no scientician!

[Assistant]
In a way it does happen fast! The most important part of fixing an injury would be to make sure you don't get any infections from it, and we do mount responses to that end in minutes (or maybe an hour or two) by clotting the wound, recruiting LOTS of immune cells and making sure that infectious agents don't enter and you don't loose blood.

But full healing is mechanistically very complex: you need to first clear all the cells that died, then make new cells in the same design as before, all the while making sure you don't loose any blood or get any infections. I'd say our bodies do a pretty amazing feat already, even the theoretically best possible levels!


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

[User] ELI5: How can we determine the duration of a second by using Cesium?

[Assistant]
A clock is something that counts the number of regular occurrences of some event, like maybe the number of times a pendulum swings.  A second is defined to be a specific number of  vibrations of the Cesium atom, approx. 7 billion vibrations. Every count of that many vibrations is called a second. (it is a very specific number, but it is about 7 billion). So a Cesium atom clock is just a fancy counting device that counts the number of vibrations of a Cesium atom.

**NOTE**: Since the clock is counting individual vibrations it can count almost 1/10 of billion of second, that is, it counts a single vibration of a Cesium atom.


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

[User]
This may seem like a silly question, but how/why does lightning occur?

I know it sounds ridiculous for a 19 year old to be asking this, but I was just staring at the sky and I realized that I have no idea why lightning occurs. Rain and the water cycle make sense to me, but lightning...

[Assistant]
Lightning occurs due to large regions of positive and negative charge that build up within a thundercloud.  When enough separated charge builds up the lightning process begins, culminating in the large discharge that we see and/or hear.  Most lightning (on the order of 80%) occurs between two clouds or within the same cloud, only a fraction of lightning reaches ground.

Now you may ask, why do charges separate in thunderclouds?  Generally convective air (the cycle of air going up and then back down) carries with it a lot of water, as the up going air crosses the freezing point in a cloud it starts to freeze.  So on the way back down it is mostly ice.  When the upwelling water collides with the downwelling ice there is a small exchange of electric charge between the particles: negative charge goes up, positive charge goes down.  This results in the large charge separation in thunderstorms (on the order of 20 megavolts).

Without the large convective regions lightning will not occur.  So relatively weak convection on the West Coast of the United States results in little lightning while strong convection over the great plains results in massive thunderstorms.


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

[User]
[Scooby-Doo] What drives people to become a Scooby-Doo villain?

There are some cases where the monsters are proven to be real. But why would anyone decide to actually become a Scooby-Doo villain? Who says, "Oh well, I couldn't hack it as an accountant. Time to throw on a lobster costume and terrorize my neighbors!" What is the chain of reasoning that leads people to do that?

[Assistant]
It's really quite simple. They know of some valuable resource but aren't able to carry out the extraction so they exploit a local superstition to scare people off.

It's not entirely unheard of, you know. During the 13th century, Castle Vauvert was a hideout for criminals who faked being ghosts to scare intruders, so convincingly that King Louis IX sent Carthusian monks to exorcise the place.


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

[User]
If the light omitted on the far side of a galaxy is significantly older than that of the front side, why isn't the shape distorted?

I can't wrap my head around this. In a galaxy that is, say, 100,000 light years across, why do we still see it as a "perfect" formation?

[Assistant]
It takes 2500x as long as that (250M years) to rotate around the galaxy. So, in 100k years, the stars only shifted 0.144 .

So, there is distortion, but it's not enough to ruin the seemingly "perfect" formation.


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

[User]
cmv: Social media is damaging our value of life chemically.

I had a thought and now I can't shake it. You guys know how babies get serotonin overdoses from cocomelon because the frames change too quickly for them to fully comprehend? Ok, how about developing teens/young adults with the ability to receive a dose of serotonin with every like they get on a post or every cute picture they come across and enjoy right at their finger tips? Maybe this is a reason you don't see many older people on social media, and when you do it's typically Facebook and they don't seem tech savvy. It's like everyone is in a rat race online and it's certainly damaging to me, considering my social status. I'm kinda poor and being sucked into a virtual reality is easier than trying to fix my life, so typically I procrastinate and become unable to do the things I want to do, in turn bringing me to this vicious cycle. Depression, play on phone, envy, plans to do better, sense of failure due to social status, repeat. I don't think I'm alone here. And there's definitely a serotonin factor because I'm on this phone 24/7 but claim that doing things I love isn't enjoyable enough to waste my time on. Ironically. Anyone have any say in this? I genuinely see social media as a disabling drug and it's just extremely hard to quit.

[Assistant]
>You guys know how babies get serotonin overdoses from cocomelon because the frames change too quickly for them to fully comprehend?

I don't think this has been studied to be able to make that claim.