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

[User]
CMV: Your tip shouldn't change depending on the cost of the meal

I don't really get why tips are typically thought of in terms of percentages rather than absolute dollar value. Like--it's not substantially more work for the server to bring you a sixty dollar bottle of wine than a five dollar shot, so why would the former substantially increase how much they get paid and the latter have a negligible impact?

What i'm proposing is that you should work out an amount of money that you typically tip that more-or-less equals the average dollar amount you'd be tipping on meals, and use that as the baseline rather than 15%. Like if your meals on average cost around 30$, you should have a baseline tip of 5$ whether you're getting a 15$ meal or a 45$ meal. (That's if we accept that 15% is an appropriate baseline tip--i know there's a push in some areas for that to be higher. i don't have a strong opinion either way but am probably vaguely supportive of people tipping more if they can afford it.)

You might still have reasons to adjust that tip up or down. I don't necessarily think you should always pay servers the same--if you're staying for a long time, or having multiple courses, or have a large/disruptive party, or are going to a place with very good service or strict regulations about how the servers can act, i think those factors should increase how much you tip. And some of them are loosely correlated with expense--but I don't think that correlation is strong enough to really justify using expense as a proxy instead of tipping more specifically when those factors apply.

Advantages of this:

\-increased income stability for waiters. it's still contingent on how many tables you get and whether they're generous tippers or not, so hardly ideal, but now at least it's not about whether the table ordered a 100$ bottle of wine or a 20$ round of shots

\-more equal for waiters at cheap places. it doesn't seem right that waiting at a place with high prices is a way better-paying job than waiting at a place with low prices, all else being equal. it's possible that the place with high prices is a more demanding job, but it's also totally possible that it isn't.

\-doesn't require constant recalculation. You'll probably only need to work out how much you should be tipping every few years as your income changes and you start being able to spend more--the rest of the time you can just give a steady dollar amount, with more for good service. Obviously I don't expect you to exactly calculate the average, just give a good enough estimate that you probably aren't paying less than you otherwise would overall. This is a comparatively minor issue but, well, rule of threes y'know?

The only real problem with this that I've been able to see is that it bucks social convention so you'd seem like a dick whenever you get an expensive meal and leave a comparatively small tip, even if you're actually being more fair overall. But it doesn't seem right to continue tipping unfairly just to look good/fit with social norms.

Incidentally, i'm also down for abolishing tipping as a practice, but what I'm proposing here is more of a best-practices when you go to a restaurant--I think it's pretty obvious that the way to get rid of tipping is to put pressure on the restaurant owners, not to screw over the wait staff. (Not very interested in debating this part of the post though)

EDIT: I'm not advocating for a flat-rate tip. I'm fine with tipping more for things like good service, expertise, or having labour-intensive orders. Also, in my system, different people will have different baseline tips, depending on how much they can afford to spend. I'm saying that I don't think the cost of the meal itself should change how large a tip is left, not that nothing should.

[Assistant]
>What i'm proposing is that you should work out an amount of money that you typically tip that more-or-less equals the average dollar amount you'd be tipping on meals, and use that as the baseline rather than 15%.

...

>-more equal for waiters at cheap places. it doesn't seem right that waiting at a place with high prices is a way better-paying job than waiting at a place with low prices, all else being equal. it's possible that the place with high prices is a more demanding job, but it's also totally possible that it isn't.

Do you think a server at Denny's goes through the same training or is held to the same expectations as one at a fancy Italian joint?


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

[User]
[Star Wars] How exactly does the senate ordering 5 million more clone troopers help the republic in clone wars season 3?

In clone wars season 3, there are a few epsiodes about how the senate wants to bankrupt the republic so they can order more clone troopers. All the senators in support of it talk about it like it will immediatly fix all their problems. But it takes at least 10 years to grow and train a clone trooper so how exaclty does this help them? Does Kamino just have 5 million fully trained clones just sitting around and the republic just needs to pay for them? Or would it actually jave done nothing and the whole thing was just part of palpatines plan to destroy the republic?

[Assistant]
> Or would it actually jave done nothing and the whole thing was just part of palpatines plan to destroy the republic?

This right here. Ordering more troops was just a good sound byte, a measure of political grandstanding to make it sound like the government was doing something, even if it was functionally useless. The seemingly endless conflict of the Clone Wars made many senators vote out of fear rather than logical deliberation. It's why they eventually cheered when Palpatine declared himself Emperor, because at the time, it seemed like the best way recover from the war and prevent another such conflict from happening again.

But at the same time, having it go through would mean the Republic's budget, which was already on a heavy war footing, would become even more dedicated to a war economy, which is exactly what Palpatine wanted for his Empire.


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

[User] [Star Wars] How did Darth Sideous fight Yoda so well with a light saber despite not having anyone to train against for years?

[Assistant]
Being good with a lightsaber has more to do with proficiency and strength in the Force than it does with raw physical know-how.

Notice when Ben was showing Luke how to use the lightsaber on the Millennium Falcon: it was all about letting the Force guide you, not about learning fighting forms.


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

[User]
If water is a cycle, why is it such a big deal to conserve water?

Like "save water for the fish" and stuff like that.

[Assistant] You may not be aware of this, but the water table is many areas of the world is depleting faster than it is regenerating, causing farmers to have to dig deeper and more expensive wells, which in turn taxes the power grid. The water depletion is largely due to the farming of non-native crops, and the rather water intensive smaller farms that India, Indonesia, etc tend to have.


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

[User] Which Western philosophers have written (significantly) about intuition?

[Assistant]
Henri Bergson has built his entire philosophy about it.

Less specifically you might be interested in the line of thought stemming from Counter-Enlightenment - Berlin thought that Bergson was the culmination of it.


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

[User]
If the heat death occurs, how can time itself stop?

Since space and time is the same thing, how can time stop if the heat death occurs? The low energy particles evenly distributed in the universe would still be distributed in space, with space between them. Right?

[Assistant]
Love this question!

This is where metaphysics and philosophy blend. Also, a classic question becomes metaphysically/philosophically beautiful!

If a tree falls in the forest, does it make a sound?

Most people answer yes. What you're saying is that it exists independent of our observation.

Relating back to the bigger question, you're saying that our understanding of time is the disorder of energy and the spreading of energy; that our definition of time is the ability and existence of energy transfer.

Well, the only real reason for understanding time like that is because that's the only way we have/ may ever comprehend time. Once all energy stops transferring (we're dead), who's to say that energy transfer is time anyway? Sure that's the only way we comprehend it, but it could be something entirely different and not understandable to us.
So to answer your question, maybe (like almost every other metaphysical question's answer).

Tl;Dr
Just because energy transfer is our way of observing/comprehending time, doesn't mean that that is what time is.


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

[User] ELI5: why does Hulu play the same ads over and over, knowing very well we'll hate them more for it?

[Assistant]
TL;DR: You may be seeing an ad very regularly because it is a very large order that is specifically being served to your age/gender/location. The business featured in the ad will pay different fees to have their commercial run more or less often.

-----

Ad streaming services like Hulu, GoogleAds, or those served in mobile games work much like renting any other advertisement. The merchant who wants to place the ad will design what it looks like, sounds like, says, etc. and then pay the ad streamer to play it a certain number of times.

When you rent a billboard you pay for X-number-of-days on display. When you pay for a TV commercial or radio message you pay for X-number-of-seconds. When you pay for a GoogleAd, you pay for X-number-of-clicks. When you rent from an internet streaming service you pay for X-number-of-streams.

Say that a streamer like Hulu gets two ad orders, one is for Product A and 10 million views and the other is for Product B and 1 million views. The Product A commercial is 10x more likely to appear than Product B because they need to serve it more times to fill the larger order.

There are also a couple of other factors involved depending on the complexity of the advertising network. If the advertiser uses targeted ad placement (like Hulu and Google) then when a merchant buys an ad they can put in an extra criterion -- 10 million views by males, aged between 18 and 30, living in North America. The ad streamer will then use data related to your IP address and their own personal databases (such as your Hulu account) to make good guesses at when to play which ad.

You may be seeing an ad very regularly because it is a very large order that is specifically served to your age/gender/location.


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

[User] ELI5: Why do songs get stuck in our heads? Are certain songs more likely to be stuck in our heads than others?

[Assistant]
I think its because theres a feedback loop in your brain. Your brain cant accurately remember the whole song and therefore sees it as an unfinished task, so it decides to repeat the task until it finishes it.

Thats why the best way to get a. Song out of your head is to listen to it again!


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

[User]
[GREEN LANTERN] Could a ring (any color) cure someone of a disability?

Seems like disabled people would have a lot of emotion, positive or negative.  So let's say someone that was paralyzed got selected by a ring, could the ring restore their ability to walk?

[Assistant]
Not exactly what you were asking, but the latest Earth GL brought someone out of a coma with the ring, a feat thought to be impossible for GL rings. So he could possibly heal people in other ways.

I don't know too much about the White Lanterns, but they/he could probably do so as well.


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

[User] ELI5 How did someone originally assign value to the different variables of time?

[Assistant]
Do you mean units of time?

Like seconds?

Well, days, years and lunar months are pretty easy to observe.

Now, 12 is a great number its better than ten. You can only divide 10 by 10, 5, 2, 1 but you can divide 12 by 12, 6, 4, 3, 2, 1. As multiples of 12, 60 & 24 are also useful numbers.

So a day was divided into 24 hours and then hours into 60 minutes and minutes into 60 seconds.


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

[User]
[X-Men] What is Omega level mutant?

How do you measure it?

Is if a fair fight if one Omega level mutant fight against another Omega level mutant?

[Assistant] An "Omega Level" mutant is one whose power has no definable upper limits - their only real limits are their own physical limitations (eg, their reaction times, their stamina - their ability to keep up the effort to use their gifts), not that of their power. That's the most recent definition of what an "Omega-Level" mutant is, anyway.


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

[User] ELI5:IfIf people can be addicted to things like the adrenaline rush and the feeling of being high, Can people be addicted to Depression?

[Assistant] If they are depressed for too long, it becomes the new normal for them. When they move out of depression, it can be a strange experience for them and want to return to that state. It has to do with what the person believes is the normative behavior.


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

[User]
[MCU/What If] Question about Strange Supreme.

So Strange Supreme tried using the Time Stone to prevent Christine from dying, but every attempt had failed. So I wonder, why doesn't he just try seeking out some necromancy spells or the other 5 Infinity Stones to bring her back from the dead? Sure, it may create a whole new set of issues, but at least it's trying something new when clearly the current method isn't working out.

[Assistant]
Strange is arrogant enough to assume that when he comes up with a solution, it's the ONLY solution. He can sometimes break this pattern, but it's a flaw that all of his variants across the multiverse share to some extent.

He might have also decided that using the time stone would bring Christine back exactly as she was. Necromancy and other magic would bring something else back to him. Whether it be her soul in a rotten body, or a facsimile that was never the real Christine in the first place. He wanted her back completely, and would accept no other solutions.


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

[User]
Do you listen to economics podcasts? If so which ones do you like and would recommend?

I have been listening to NPR Planet Money and Freakonomics for a while now. I like them both because they do a fairly good job of balancing technicality with entertainment. I recently began listening to EconTalk and like that it is more technical than the other two.

What other economics podcasts are out there?

[Assistant]
1. EconTalk (recent interviews with Bob Hall, Angus Deaton and John Cochrane were good)

2. MacroMusings (technical)

3. Slate Money (more like Planet money- lots of business news)

4. Selected CATO Events podcasts (their monetary conference for example)


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

[User]
ELI5: Nihilism and it's concepts

So I'm currently reading "Fathers and sons"  by Ivan Turgenev and I can't get my head around the concept of nihilism explained by Bazarov despite googling it.

What does it mean by nothing exists? Or that nothing has any value?

[Assistant]
There are different forms of nihilism. The most commonly examined is 'existential nihilism' which basically states there is no intrinsic value in life. Simplified, the universe exists. In that universe, you come to exist, not because you are meant to, or supposed to, but just because it happens naturally, like bacteria growing on old food, and you will eventually die, and that this event is essentially insignificant with respect to the universe. Hence, all meaning we draw from life is invented by us. Your life has no real purpose or result of significance in the totality of things.

There are other concepts of nihilism, which posit that knowledge is impossible, or that reality is false, or that morality does not exist. It is a broad topic. The unifying theme however is that some aspect of what we consider 'meaningful' either is not truly meaningful, or does not actually exist.


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

[User]
ELI5: How do self-cleaning ovens work?

I don't have any water hose attached to my oven so how could this work? Little dirt eating nanobots?

[Assistant] The oven door locks closed and the oven heats up much hotter than you would use it for baking - 800 degrees or more. This literally burns off most of the grease and crumbs in the oven, leaving behind a little ash that can be wiped up with a damp cloth.


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

[User] ELI5: How can stuff be "rediscovered" in museum collections? Don't museums keep a detailed list of everything they have?

[Assistant] Not all museum records are as good as you might hope. Detailing everything in a museum collection can be quite hard. And then keeping the records and catalogs up to date is a continuous effort. Things get mislabled or misplaced all the time. If you have a giant collection you might only look at an artifact once every century. So it can take quite some time before an error is discovered. Museums are getting better at cataloging things as digital catalogs can store more information and it is easier to identify artifacts as you have much easier access to information. So museum curators are getting more time to go though their artifacts to make a more detailed catalog and find errors in previous catalogs. So you are getting more and more stories about museum curators finding things in their collections that for some reason did not have a catalog entry.


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

[User] In microeconomics, the goals of the household and firm are presented as equations- but do we have one for an efficient government?

[Assistant]
Yes. It depends on what you're modeling, but usually for questions about what the government "should" do, we use a type of model called a "social planner's problem" (SPP). Here, we have to make assumptions about everyone's utility and the relative weights that we put on their well-being. Sometimes they assume an all-knowing planner, and sometimes they don't. For instance, it's impossible for the government to know everyone's preferences better than themselves for every good.

Usually, the planner is trying to allocate resources to maximize collective utility. This differs from a competitive equilibrium (CE), in that that problem revolves around what people do in their self-interest. Often social planner problems will revolve around when the results of the SPP and CE  are different for some reason, for instance if there's an externality.

On the other hand, sometimes economists model government actors not as benevolent social planners but as self-interested agents with their own agendas. This falls under a theory called "Public Choice".


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

[User]
[Star Wars] Why do the younglings in RotS call Anakin Master Skywalker

You are on this council, but we do not grant you the rank of Master

So why do the younglings say Master Skywalker, there are too many of them. What are we going to do?

If he wasnt a master?

[Assistant] Master seems to be an honorific to anybody of a higher rank than you in the order. Padawans call address Knights as "Master insert name here", for example, in The Clone Wars series Anakin is addressed as Master Skywalker not only by his own Apprentice, but Barris Ofee, Jedi Master Luminata Unduli's padawan.


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

[User] ELI5: Why in 3D software (like games or 3D modeling apps) if you get too far away from the center point (0, 0 ,0) things get really glitchy and broken?

[Assistant]
In a computer you only have a certain number of "bits," to use to store a single number. These bits work just like digits do in normal math, so I'll use those in this example instead of binary since it's the same concept.

Imagine we have 4 digits to work with: `0000`. With those 4 digits, we can store any number from `0000` to `9999`. We can also put a decimal place anywhere within those 4 digits, so technically we can also go from `.0001` to `9999.`. This proves to be a problem though, since as the number we need to represent gets bigger, we need to move the decimal place further to the right, losing precision.

**Practical example:** We have 2 objects in our game which are `0.100` units away from each-other. Object\_1 is at position `0.100` and Object\_2 is at position `0.200`. We then want both of these objects to move 1000 units away, so we take `0.100 + 1000 = 1000.1` and `0.200 + 1000 = 1000.2`, except **uh oh,** we're now using 5 digits when we can only use 4!

This means the digits to the right side have to get cut off, so `1000.1 -> 1000.` and `1000.2 -> 1000.`. **Uh oh** **again!** Now both of our objects are occupying the same position! It's not hard to see how this can lead to problems in games when you start dealing with large scales.


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

[User]
Do masculine and feminine nouns in romance languages shape gender roles in those countries where it's primarily spoken?

I know that all nouns in Spanish are masculine and feminine but some occupations like lawyer is"el abogado" and teacher is " la profesora". Does that affect gender roles in those countries? Are men more likely to become lawyers because of the association of lawyer with men via the noun (same with women and teachers)?

Not sure of the occupational demographics of those countries so these terms could be bad examples.

Marking this a social science since it deals with more in the realm of sociology more than linguistics but I would really love to know the origin of these nouns as well!

[Assistant] Most professions in Spanish and Portuguese have a masculine and feminine version of the word. Abogado/abogada, profesor/profesora, medico/medica etc. A better question might be how do the masculinity or femininity of a noun reflect the views of society about men and women. Why are the words "snow" or "rain" feminine while the words "fire" or "earthquake" are masculine? Or why certain words have double meanings and what they say about gender. For example in Spanish "esposas" means "wives" and "handcuffs". In portuguese "piranha" is a word for both the fish and slut.


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

[User] [Deadpool] Would it be possible to permakill DP by shoving him into a vat of molecular acid and closing the lid? That seems like something he couldn't come back from.

[Assistant]
Even without a Thanos curse, that acid won't last forever. It'd eat through Deadpool's regeneration, absorbing and combining with the regenerating flesh, until it becomes too weak to affect it.

You could keep filtering and refreshing the acid. That will effectively *neutralise* him, but still wouldn't *permanently* kill him. "Permanent" implies that you would *stop* the acid bath and he'd still be dead.


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

[User]
[Marvel/AoU][Spoilers]Thor's hammer

Was Vision able to lift Mjolnir because he is truly and fully good? Or because he is not actually a living thing (or is he??)?

Just as an elevator would still go up if the hammer was in it, would an android have the same ability?

[Assistant]
The Mjlnir magic/tech determines intent. Back when the redneck's trucks were trying to yank it out of the ground, they couldn't. The hammer determined the intent of the guy behind the wheel of the truck, and found him unworthy, therefore the truck couldn't budge Mjlnir.

Vision's intent is good, therefore the hammer determined him worthy.


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

[User]
Building a website with only HTML5 and CSS3 - No Javascript

Im thinking about building a site with only pure HTML and CSS and no JS apart from the content us page.

My question is if it is built without JS are there any downsides to it? I am trying to achieve a perfect score on lightbox and im thinking a static site without JS will allow me to do it.

[Assistant] If you don't need client-side interactivity, yes, absolutely, that's what you should do. In fact, there are way too many websites that use JavaScript when all they need is a static page with HTML and CSS. Even your "contact us" (assuming that's what you meant) probably doesn't need JavaScript. Just use a form.


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

[User]
[Star Wars] The Jedi are always warned that it they succumb to the dark side, it will consume them till they essentially lose their identity. This is clear with Anakin/Vader and in a sense, Maul. Palpatine/Sidious and Dooku/Tyrannus don't seem to be consumed in the same way. What's the reason?

To add a few more points:

Anakin was consumed by the dark side, he almost completely destroyed his identity and became Vader. Maul also loses his mind in the end. Both of them are essentially used by Sidious to do his bidding.

However, this is not the case with Dooku (or Sidious). They both preserve their original identity and do things by choice. They're not consumed in the same way at Vader and Maul.

What is the difference between them? Why is it that some Sith are consumed by the dark side and become slaves to it, while others control and wield it?

[Assistant]
Dooku was Yoda's apprentice and Qui Gonn's Jedi Master. When he left the Jedi Order, it was over the protest against the corruption of the Galactic Senate and indirectly the traditions and inactions of the Order. A scant decade later, the former Jedi turned Count was already willing to enslave entire colonies, commit genocide, and participate in a grand conspiracy to murder all of his former friends and colleagues.

Yeah, the dark side corrupts.


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

[User] ELI5: How did the ancient civilizations used to make ice?

[Assistant] They didn't make ice. Wealthy people would have giant blocks of ice shipped to them from cold areas, keeping it cold by packing it in a lot of wood shavings as insulation. It would get shipped by boat or animal drawn cart. Before that was a feasible thing to have done, only people in cold areas had ice.


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

[User]
who reviews applications for graduate school?

professors? The department head? a different group of people?

[Assistant] Usually the director of graduate studies with a small committee of faculty members. If an applicant mentions that they want to work with a specific professor, the committee will probably run the application by that professor.


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

[User]
ELI5 gas prices and how they get away with charging fractions of a penny

Gas is the only thing I ever see as being listed $3.599. How do they get away with this? I assume this is done to make their prices look cheaper but why are they allowed to do it? And even more so why does my total always wind up coming to a full cent amount? If I buy two gallons at $3.599 then my total should come to $7.198 right?

[Assistant] Petrol is one of the few things that you don't have to buy in units - you just pour until you have enough.  For this reason the amount that you get is rarely a whole number and so you're already dealing with fractions of pennies when it comes to the final price.  If you add into that the fact that many people have tens of gallons then it makes sense for the company to say that 1 gallon is $3.599 rather than the more obvious 10 gallons is $35.99.


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

[User]
[Star Wars] Does the amount of Force users in the galaxy have any affect whatsoever on The Force itself?

Darth Bane seemed to believe that having too many Sith around somehow weakened the dark side of the force and diminishes the power of their Order. Does The Force have it's limits? Is there such a thing as "too many force users"?

[Assistant] He believed collaboration between Sith made them weak.  The weak sith would band together to kill the strong, weakening the sum of their power. Merely existing in greater numbers didn't inherently weaken the force.


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

[User]
[Batman] Are any of the Robins destined to be better fighters than Batman when they mature? Or will Batman's "non-stop martial arts lessons into his 20's" always give him an edge over them?

Bruce Wayne seems like he went from being a kid and pretty much did nothing but train into his 20's.

The Robins started crimefighting as kids and their lives don't appear to be non-stop training as much as Bruce's was.

Does the fact that they started crimefighting earlier give them an edge over Bruce's timeline, or will they never quite reach the fighting ability that peak Batman has?

[Assistant] Not all of them are destined, but it is considered to be highly likely and is going to be inevitable that of the Batfamily, at least Damian and Cass, are going to surpass Bruce in that manner, with everyone acknowledging that Cass is going to be the best martial artist and fighter on Earth when she grows older.


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

[User]
[Harry Potter] Can a ghost become a Secret Keeper?

Pardon me for not giving specifics--this is obviously a delicate matter I am bringing to you.

In the course of my life time I have amassed quite a few Galleons. Rather *a lot* of them, to be perfectly blunt and honest. My grown son and daughter, however, are selfish, irresponsible piles of dragon dung who are waiting my demise like vultures over a sick re'em, waiting for an inheritance they'll squander within the week.

My dear departed grandfather, still on this Earth, has volunteered to be the subject of a Fidelius Charm to hide the location of the money, to be diverged only when he judges that my children, grandchildren, or distant descendants are worthy of their inheritance.

I am eager to perform the charm, but I must ask: is this even possible? Does my dear, semi-departed grandfather possess enough of a present soul for the concealment of the secret? Could this have any adverse side effects?

I am getting on in my years and would rather my Galleons go to a worthy heir, no matter how many centuries have to pass. Please help, and I'll have my elf clean your attic or send a few Sickles your way.

[Assistant]
>How does that work? said Madam Rosmerta, breathless with interest. Professor Flitwick cleared his throat.

> An immensely complex spell, he said squeakily, involving the **magical concealment of a secret inside a single, living soul**. The information is hidden inside the chosen person, or Secret-Keeper, and is henceforth impossible to find  unless, of course, the Secret-Keeper chooses to divulge it. As long as the Secret-Keeper refused to speak, You-Know-Who could search the village where Lily and James were staying for years and never find them, not even if he had his nose pressed against their sitting room window!

*Harry Potter and the Prisoner of Azakaban*, Chapter 10  "The Marauder's Map"

Emphasis on living.


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

[User] ELI5:What does middle finger sign actually mean? how did it originate?

[Assistant]
The gesture dates back from Ancient Greece and Ancient Rome, as a symbol reminiscent of sexual intercourse, and was often used towards a people as a reference to "a male who submits to anal penetration." It's Latin name, *digitus impudicus* translates to the "shameless, indecent or offensive finger."

It is said that it came to the United States via Italian immigrants, and was first documented being used in a baseball team photo when Old Hoss Radbourn flipped off the cameraman.

TL;DR: It is used to symbolize anal sex and originated in Ancient Greece.


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

[User]
[REBOOT] Why did losing games nullify the sprites? Wouldn't winning mean breaking your computer?

/\

[Assistant] This isn't a personal computer; this is a mainframe.  The games are probably some user running unauthorized software on a work terminal and this causes corruption that the sprites can obviate by ensuring that the user doesn't reach a win condition.


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

[User]
ELI5: how do animals that come back from extinction overcome inbreeding problems

This got me interested as I was reading about Diego the tortoise who revived the species from extinction. This may be good and well but what happens to the inbreeding which is said to weaken the genetics of the animals and also magnifying the chances of recessive geenes manifesting.

[Assistant]
They don't. At least not in the short-term. In the short-term they're absolutely will be inbreeding related problems associated with that bottleneck.

In the long-term if the species does survive, it does so because the problematic genes that have been over-represented in the population are slowly culled out by natural selection.

Since that means that the population is going to be less healthy in the short-term, that poses a big problem that can make it even harder to recover from a very low population than it would be otherwise.


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

[User] Considering a supernova can lead to the creation of new stars is it not possible that if it was a big bang which created our universe, this event could have been a common supernova on a scale which we are just too small to understand in a universe that is much bigger than we expect?

[Assistant]
A supernova is an explosion: it is a star (or stellar remnants like neutron stars or white dwarfs) which explodes and sends material traveling outward through space. It has a meaningful center from which the explosion originated. It creates star formation by adding material to the interstellar medium (the gas & dust between stars) and, crucially, by disturbing and stirring up that interstellar medium.

The Big Bang was not an explosion. It did not send already-extant matter traveling outward in a radial direction. It was a simultaneous expansion of space itself. It did not have a center-- the whole of space started enlarging. Imagine an infinite rectangular grid of points, each spaced 1 millimeter apart. Now increase that distance to a centimeter, now to a meter, now to a kilometer. No matter where you are, you will see all other points getting farther away from you, but this does not mean that you are uniquely at the center of the event--it's happening everywhere.

The extremely rapid expansion of space in the early moments of the universe meant that the mass-energy in the universe became less dense very rapidly, so that it could cool down and form things like protons (also known as hydrogen-1 nuclei), which, because the universe was still quite dense and hot by our human standards, could undergo some nuclear fusion and create some helium, the second-lightest element, and trace amounts of lithium. The universe's visible matter (i.e., not dark matter) was composed almost entirely of hydrogen and helium after this fusion ended when the universe was 20 minutes old or so.

Over time, the universe became cool and low-density enough that it was transparent. This is when the photons that hat been bouncing around in the dense hot opaque primordial plasma soup were able to stream freely in all directions. This is known as the "surface of last scattering" and is what we see as the redshifted Cosmic Microwave Background. It's by far the most important observational tool for understanding the early history of the universe, and it demonstrates that the universe was much hotter and denser in the past than it is now.

After the universe cooled further, the gas could start gravitationally clumping up and forming stars.

The universe may be infinite or it may be "finite but unbounded", like old arcade games where you can go off the left side of the screen and come back on the right side. Either way it's extremely large, so large (and expanding so rapidly) that physical material from an explosion can never travel all the way across the universe.


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

[User]
[GTA - Vice City] Why was Sonny so patient with Tommy about the "god damn" money when he knew Tommy got it all back?

So, in GTA Vice City Sonny sended Tommy for a drug deal. Both things got lost, the drugs and the "god damn" money. But when Sonny heard Tommy killed >!Diaz!< shoudn't he count two and two together to know Tommy already got "his" money back and the drugs. He refered to >!Diaz!< as a drug baron after all. So why all the patience? Why didn't he confront Tommy right after he found out?

[Assistant]
Sonny assumed that Tommy was still loyal to him, and that Tommy would repay the money owed as well as give him a cut of his profits in Vice City.  He assumed that Tommy was loyal because Tommy had refused to divulge any information on Sonny's Forelli crime family when he was arrested.

Tommy was initially sent to prison for killing eleven men.  However, Sonny pulled some strings and got Tommy's sentence reduced.  It was expected that this would be enough to permanently ensure Tommy's loyalty to Sonny and to the Forelli family.  And when Tommy killed Diaz and started really expanding his operations in Vice City, Sonny waited patiently for Tommy to do the right thing and cut him in, because *of course* Tommy would do right by the Forelli family, right?

And then when Tommy failed to do so, Sonny decided to send some of his men down to Vice City to *remind* Tommy of his duties to the family and *encourage* him to fulfill them.  Except Tommy killed those men too.  So Sonny was forced to head down to Vice City personally to deal with the upstart Tommy Vercetti... and then Tommy killed him as well.

So why was Sonny so patient with Tommy?  Why didn't he confront Tommy as soon as Tommy had taken over Diaz's operation?  It's because he assumed that Tommy, who had previously shown great loyalty to the Forelli family by not snitching in prison, would continue to be loyal and would hand over a cut of his profits.  It was only after Tommy emphatically did not do so that Sonny decided to take matters into his own hands.


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

[User]
ELI5: Why can't my eyes heal?

 So I can mend broken bones, I can heal cuts. I can fight off diseases, but once my eyesight started deteriorating at age 15 I have had to wear glasses. Why can't my eyes get better, or heal back to the good vision I had before?

[Assistant]
Your eyes aren't 'broken' they are merely 'adapted'. Modern humans stare at close-range things much, much more than their hunter-gatherer ancestors, so the muscles they don't use naturally become weaker over time (subject to some genetic and random variation) resulting in poor eyesight at range, requiring correction.

You *CAN* train your eyesight to become better, over a long period of time, with special exercises and looking at particular patterns and things, but you'll never have perfect vision once you've lost it.


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

[User]
ELI5: Does the Electoral College completely control the U.S. Presidential election?

I've been watching a bunch of videos recently, and reading articles to try understanding just how the Electoral College works and just how much control it has. The entire process confuses me a bit, I was just wondering if anyone could explain it to me very simply, as well as answering the following hypothetical question:

Say, for instance, two people (Person A & Person B) are running for president against one another, and the results end up being:
Person A gets 100% of the popular vote, and 0% of the Electoral Votes.
Person B gets 0% of the popular vote, and 100% of the Electoral Votes.
Would Person A or Person B become president?

I'm not very politically literate, so I don't even know if this is possible--I'm just curious.
Thank you.

[Assistant]
In that very unlikely situation, Person B who got 100% of the electoral votes becomes president. It is unlikely because the electoral college are sworn to vote according to the popular vote results of the state they are chosen to represent, and half of the states back that up with laws. While occasionally an electoral college voter may disobey, it happens very rarely and has never impacted an election.

Yet.


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

[User]
Eli5: How the finger light thing can tell how much oxygen is in your blood?

As the the title suggests, how is it that a little light they put on our finger when at the doctors/hospital/etc.. is able to tell us our blood oxygen levels?

[Assistant]
In blood, the oxygen is carried by some molecules.
It just so happens when the oxygen binds to those molecules they change color.
So they shine a light, read the color and that figures out what proportion of those molecules have changed to that color.


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

[User]
Since CPUs and GPUs are good at two different areas of math, arithmetic and linear algebra respectively, is there research in creating different types of processors good for differential equations and even higher levels of math?

While deep learning took off thanks a lot to better GPUs, it got me thinking if we could make other ML algorithms more viable by inventing processors good at other types of math that lend a hand to the aforementioned alternative ML algorithms.

[Assistant]
The main difference between a CPU and a GPU is the number of operations performed per "decision" (branch instruction). CPUs do better when there are lots of branches, while GPUs are optimized for more operations per branch.

The main focus of research right now is in AI acceleration. These AI processors look very much like GPUs. They use smaller data values, and have a few new instructions to do the operations used for AI (for example, dot product).


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

[User]
How do space probes make it past the astroid belt without crashing into them?

I am a huge fan of space and learning about it and I have always wondered how we don't hear of probes constantly crashing into the astroid belt. I know space is huge and have heard things like space is too big so we don't have to worry about it, but I was wondering if there was a more direct reason. I am sure the technology we have now helps plot the course but I have always been curious.

[Assistant]
Movies and such portray the asteroid belt as this densely packed minefield of rocks all over the place.

The truth is, there are miles and miles (average of 600,000 miles) between each asteroid.

As with most space travel, you have to aim your rockets *very* carefully to ever hit anything.


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

[User] Eli5: Why are railroads full of rocks?

[Assistant]
Ballast is a comparably cheap way of leveling ground that can support a lot of weight very cheaply.

Rocks don't wash or blow away, they allow for thermal cycling, more or less self leveling, easy to repack when they do sag, easy to add new material to.

Compared to say a concrete foundation, they won't crack, and doesn't require formwork during construction, and more importantly don't require extensive ground works before it can be placed.


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

[User]
[Pokemon] who decided what the starters would be and why?

pretty much the title.  just to keep things in context, let's stick to the original 150.  in-game, they are about the rarest of the rare.  who's good idea was it to make bulbasaur, squirtle, and charmander the starters?  to give every newcomer to Oak's lab a choice of the three, there has to be some kind of Pokemon version of a puppy mill cranking out starter 'mons (or a really worn out ditto somewhere).  wouldn't it have been a better idea to give a bunch of snot-nosed greenhorns a rattata or pidgey or caterpie to start with, seeings as how they're ridiculously common?

[Assistant]
>Every newcomer in Oak's lab

What are you talking about dude? I've been to Pallet town before and there were all of 2 houses there and one lab. There aren't really "Newcomers". I'd be surprised if there has been a person moving in that town for decades.

Considering their rarity odds are that these are just pokemon that the Professor had for research. He then completed his research and was kind enough to give some good pokemon to his grandson and a kid he's probably known since he was a newborn.


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

[User]
[Mother 1+2/Earthbound] Why hasn't the military gotten involved?

In both games, there are war veterans, showing that a military does exist. (In 2, one of the NPCs at the Twoson bus station claims to be a war veteran.)

In both games, conventional military-type weapons are shown to be far from useless against even Giygas' more advanced minions.

In both games, while the public may not know everything that's going on, there are some clear signs that the country is facing some kind of paranormal threat. People talk about the abductions and the zombies at least.

So why haven't the authorities responded in any way?

[Assistant]
For starters, Giygas had already influenced the entire Onett police force.  Giygas is also in control of the powerful people in Fourside, and the officers there admit that they work directly for Montolli, who is (in a bit of a roundabout way) under Giygas' influence.

And you do encounter soldiers, most likely having gone rogue, selling weaponry and explosives used in the fight against Giygas.  They don't seem to know what they're fighting, but they are helping the good guys and are seemingly aware that they're supporting the fight against *something.*

For the rest of the various armed forces, remember that almost nobody knows who or what Giygas even is.  Many people aren't aware that there's even a fight brewing, because 199X is still 10 years before the fight against Giygas even happens.  At this point, Giygas' influence is only beginning to spread and create what will become his army.

As is shown, many people fall to Giygas' influence by default until being met and sometimes "freed" by Ness' influence.  If the militaries are involved at all, they are likely influenced to be complacent and unhelpful, the example of the Onett police being the clearest analog to use for comparison.

Additionally, as is seen in Mother 3, the only military shown in the series is >!already under Giygas' influence, in that they're under the influence of somebody who had been directly influenced by Giygas.!<  Though this is long after M1 and M2, there's not much reason to believe that other Eagleland militaries would have fared much better, though they would have probably taken longer to corrupt.


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

[User]
[Monsters Inc] How does such drastic speciation occur in the Monsters universe?

Each species seems to be able to communicate with the others. Do monsters look like their parents? Can monsters of different breeds have children together? Why are so many conjoined siblings? Is it environmental or is it just a natural part of the "Monster" genus?

[Assistant] Basically, the monsters are dogs, whereas humans might be considered cats. Cat breeds may have small differences in facial structure or proportioning, but all breeds of domestic cats are very similar. Then look at dog breeds and see differences as drastic as that between a chihuahua and a pit bull. This comes about because dogs have a 'slippery genome'; they have back up copies of dna, so if a mutation occurs that say, screws up the sequence responsible for hemoglobin, that would normally cause the fetus to die/miscarry, the dog fetus just uses the back up copy and continues to term. Thus dogs can breed much more significant mutations and still function as one species, because they can shrug off what would ordinarily be a fatal mutation. For the monsters, it is the same except even more extreme.


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

[User] ELI5: Why can I go from morning to night, and my mouth tastes fine, but after only a few hours of sleep, it tastes like a bum's nutsack?

[Assistant]
During the day you open your mouth, eat, speak, and do many other things that change the contents of your mouth.  Not in sleep.

What's more important though, is how you know what a bum's nutsack tastes like.


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

[User]
CMV: Big AAA video games get review scores that are too high, making review scores less useful

**TL;DR**

**AAA Games should be rated more like blockbuster movies where it is far rarer to get an average rating of 8.5/10+.**

On sites like Metacritic it is fairly common to see big movies get review scores below 8/10, often below 7/10.  Sometimes a big movie comes along that gets a very high review score but these are not the norm. By comparison, big AAA video games that are not completely broken almost always get 7+ with many games getting 8.5+. This creates a problem.

If the bar for a mediocre AAA video game is 7/10, then you realistically only have 4 numbers on the scale (7,8,9,10) to discern where most AAA video games land in terms of quality.  This makes the review scale less useful since there are fewer numbers available for most games that people are thinking about buying.

I think games would benefit from a lower average review score since review scores would become more useful.

[Assistant]
Well those ratings take a lot into account. What genre is it? Is the story important to this genre? How are the graphics? Any noticeable bugs/glitches? Is there replay value in this game? Hows the dialogue/voice acting? How are the mechanics?

When you throw as much money as AAA studios do at these games, youre most likely going to end up on the higher end of most of these categories. Then you have to take into account that theyre rating the game for what it is. Mechanics are far more important than story in the new CoD because that game isnt about the story. Where as with something like RDR2 or something similar, the story is vastly important. The value placed on each category varies from genre to genre.

If one of the AAA studios puts out a game that gets a 3/10 theres going to be a lot of people fired and the people working on that game understand that. On top of that when you invest that much money, high quality is the only thing youll accept because its the only way you make money at that point.


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

[User]
ELI5: How are animated films directed?

With live-action the director is physically present to... direct the actors, cameraman, crew, and so on. How would it work in animation where all the parts are so separate?

[Assistant]
It's pretty similar, they plan out the film, storyboard, and so on. Animation is done with simple models at first, they work on the shots, camera movements etc.
The big difference is the finalized shots take hours or even days to render out.


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

[User]
[WH40k] What is the Emperor's perception of reality, space time, the little humans who pray to him, everything?

...

[Assistant]
There are two Emperors.

There is the psychotic being on the Golden Throne, driven mad by thousands of years of pure, unadulterated warp containment, the prayer of the zealots of man and the sacrifice of millions of innocent psychers.  This being sees time as we see it, every second of the day, frozen for eternity.... wanting to die but given no succor.

There is the remnant of the original Emperor, the embodiment of order and the shield of the souls of man in the afterlife of the immaterium.  This remnant is everything pure and good that was sacrificed the moment the Emperor truly saw the horror that his son Horus had become and resigned himself to utterly destroying him.  This being is a true deity of the warp, the embodiment of order, a light in the darkness, he sees time flowing irregularly through the galaxy, time means little to the beings in the immaterium.


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

[User]
What would happen if you threw a snowball that was near absolute zero at a person?

Or just dropped it on the ground or something similar.

[Assistant]
Surprisingly little would happen.  It would hurt a lot more than a normal snowball and could cause frostbite, but the heat required to take ice at absolute zero up to 0 C is comparable to the heat needed to melt that same amount of ice.

The only applicable weird effect that happens when ice is extremely cold is that the heat capacity actually goes down, so it's even easier to heat up at lower temperatures.

It would also either be as hard as a rock or very powdery, depending on what it was like when it was cooled down.


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

[User]
[Star Wars] Is there any real reason to engage in surface combat compared to just controlling the orbit around a plant and bombarding surface targets with impunity from orbit?

If you don't want to destroy infrastructure, you can just use modular yield explosive warheads or kinetic impactors. Currently, we can send a Predator drone to launch a missile to kill everyone on one side of a wall but leave the wall and the people on the other side intact.

[Assistant]
Theatre shields exist in *Star Wars*: a defending force can produce a shield bubble over strategic areas even if they can't put a shield around the entire planet. This is why the Empire lands on Hoth and fights a ground campaign in *The Empire Strikes Back*: the shield precludes a precision bombardment and they can only leverage their orbital and air superiority once Veers destroys the shield generator. While they could conceivably bombard the area around the shield so heavily that the ground underneath is liquified, this would deny them the opportunity of capturing surface resources, prisoners, intelligence, etc.

For the attacker, theatre shields also have the happy effect of concentrating combat around a handful of areas. This explains why *Star Wars* armies routinely expect to capture planets with bizarrely-low numbers of troops.


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

[User] What philosophers should I read before Nietzsche?

[Assistant] The healthier view is that you should just read some books *about* Nietzsche before reading Nietzsche.  Tracking his influences is just too damn hard.  No one is ready to read Nietzsche, least of all Nietzsche.


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

[User]
[Doom 2016] Has someone commercialized The Slayer?

I don't know how much the average earth citizen knows about The Slayer but there sure are a lot of these "Doom Guy" action figures all over the place.

[Assistant]
Those are scarecrows to keep the demons away. Notice how when you find them in vents and hidden passages, there are no demons.

A more intelligent person would have put them in more public places and near the doom portal.


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

[User]
(WarHammer40K) Why are Titans so darn important? Furthermore, what are they, exactly?

Whenever I watch a WH40K cutscene or any gameplay from a game, all they ever seem concerned with are these giant, walking mechs.

They always seem to talk about them like they're the greatest things since sliced bread, but never really expound on it. Can anyone explain precisely what they are, how they're made, why they're so relevant to the Imperium, how they're even used(how do they use them on other planets if they're so big?), and why they always need to be protected?

[Assistant]
Titans have a number of valuable attributes.  One, they are avatars of the Emperor in his form of the Machine God, and are thus holy icons.

Two, they are bad ass motherfuckers.

Let us put in easily compared perspectives of Epic 40k: (A relatively accurate simulation of warfare commonly played amongst the lazy nobility of certain upper hives)

**A Leman Russ battle Tank:**
Speed, 25 CM (a cm is about the length of a battle tank, so go with 10 meters per cm).
Combat effective range:  45 cm
Firepwer (in the form of its main gun, as well as twin sponsoon heavy bolters), 3.
Armour of a 6+.
Assault Capability: 1 (this is for directly assaulting enemy positions)

**A warlord titan** (the essential main battle titan and backbone of the titan legions):
Speed: 15 cm
Armour: 6
Void Shields: 6.  These are rechargeable layers of defense which are powered by the fusion reactors.
Damage Capacity: 12
Armament:
32 Firepower (or an assortment of specialized and very nasty other weapons).
Assault Capability: 30 (this is for directly assaulting enemy positions)

So you see, a single warlord titan has the firepower of 11 battle tanks, but also has the damage capacity of 12.  However, it carries rechargeable shields which allow it to shrug off hits that would devastate a tank battalion.  But the real strength is that when assaulting defending positions, a single warlord titan is **30x** more effective than a Leman Russ.

Now, these are just stats from a simulation.  But you can see why its such an asset on the battlefield.  Its only real weakness is that its a larger target and less maneuverable.

Titans are difficult and complex to manufacture.  but they can last for thousands of years if properly maintained, and recovered from the battlefield.  Only the Adpetus Mechanicus can manufacture them, and only on the best of forge worlds.  They're deployed via special dropships which are large enough to carry them.  They come in a variety of sizes and models, but there are four general lines used by the imperium (and even these will vary by forge world or construction date).

**Warhound Titan:**
Warhounds titans are the smallest titan, and are used primarily as scouts for the main Titans.  They're 25% faster than the other titans, but only mount a small amount of shields.  They are, however, still deadly machines and carry the equivalent firepower of four Leman Russ battle tanks.

**Reaver Battle Titans:**
Reavers are the "mediums" of battle titans, and the smallest that are capable of carrying anti-titan close combat weapons (the most effective way to take a titan out, is at close range with another titan).  Their maximum firepower is equivalent to 8 Leman Russes.

**Warlord Battle Titan:**
As previously discussed, this is the most relied upon battle titan.  Their  additional shields give them great staying power.

**Imperator Titan:**
The largest titan in imperial service, this beast is incredibly rare and incredibly dangerous.  They mount, conservatively, the equivalent firepower to 20 Leman Russes, but it is difficult to quantfy giving the sheer insane power of their Plasma Annihilator and Hellstorm Cannons.

In combat a Titan represents the ability to concentrate the firepower of a battalion of tanks.  Their strength in close assault is unmatched, and only the insane will defend a position against an approaching Titan.  But their true greatest strength is their ability to directly engage the Titans of the enemy.  The imperium isn't the only force which can bring these constructs to battle.  And the best way to stop a titan, is always with another titan.

edit:  Added some commentary explaining the source of the information and fixed a few typos.


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

[User]
Why do certain parts of our body reproduce
themselves when destroyed (eg skin) and others
don't?

For example, if i rip or burn the skin on my fingertips, it will grow back. Or scars are somehow covered up.. But why if we cut a person's finger, or a whole hand it will not grow again..? Can this become under certain circumstances..? Any other examples more microscopically ?

[Assistant]
Some parts of our body contain cellular machinery to heal wounds, and some do not.

In the skin, if you have a deep cut, the stem cells (basal keratinocytes) in the stratum basale need to divide and reform into a single layer to start regenerating skin cells in the epidermal layer above them.  If they are too far separated, this regeneration will be incomplete, which is why stitches are sometimes necessary.

If you cut off a finger, there's no basal structures that can regenerate and the architecture is so complex, simple cell growth will not suffice.

Other areas in your body - like your GI tract - work in much the same way.

Your liver can take quite a bit of damage and still regenerate - from as little as 25% of the original structure - largely because other liver cells will proliferate and fill the space, restoring function if not the original architecture.


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

[User]
Can a virus have a really long incubation time, say months, be highly infectious during incubation and have extremely high mortality rate?

As in a virus that gives little to no symptoms for months or even years and suddenly becomes highly lethal?

Would we, with modern medicine, even be able to detect such a virus before it is way to late?

[Assistant] HIV is such a virus. After initial infection People can be asymptomatic for years. - 10-15 years in fact. During this latency period Tests would still reveal HIV+ status, but many who are infected do not get tested and continue to spread the virus. Which is why they encourage people who are risk of HIV to get tested regularly  to prevent asymptomatic spread.


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

[User] How does a spacesuit insulate so well and is it still cold if you're in space while you wear one?

[Assistant] Actually, space suits are designed to cool the user, because in space, there is no medium like the earths atmosphere to carry heat away. Getting rid of heat in space is a huge problem so contrary to the premise of your question, NASA spends a lot of time thinking about not how to warm the things they put in to space, but on how to get rid of heat from the sun, and heat from within. You can't just blow the hot air, and mix it with cold air. There is no air in space to blow over the station and carry away excess heat.


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

[User]
ELI5: What causes the Redshift as seen in last nights lunar Eclipse?

Would it be correct to assume it has something to do with light passing through the Earths atmosphere?

[Assistant]
It's not redshift, that's caused by going really fast.

But yes, it was light passing through the Earth's atmosphere.  Basically you were seeing the same thing as sunrise and sunset on the Moon through the Earth's atmosphere.


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

[User]
ELI5: If you throw a wad of wet, scrunched up toilet paper at a wall, it sticks even after the water has evaporated out of it. How come?

Im sure most people have seen wads of paper towel and toilet paper stuck on public restroom walls and ceilings, from people who wet them and then threw them against the surface. If you were to throw a dry piece of paper at a wall, it wouldnt stick, so, on a more molecular level, how come the TP continues to stay in place even after the water has dried out of it?

[Assistant] Paper is basically wood pulp (often with other additives), held together by glue. In toilet paper specifically, the glue is very soluble in water. This is so when you flush it, the glue melts, and the paper dissolves. If you throw wet toilet paper at the wall, the glue is partially dissolved, and will stick to the wall. When it dries out, it's still stuck to the wall.


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

[User]
[Overlord] How does sacrificing XP work?

I don't think I've ever seen an RPG style game where you need to sacrifice XP, or at least not in the way Overlord does it. Wouldn't bringing yourself down a level or something cause problems like suddenly being unable to use some of your equipment or abilities?

Also, how does Ainz increase his XP in the fantasy world compared to Yggrdasil?

[Assistant] Dungeons and Dragons 3.5 has XP costs for a lot of spells, though Pathfinder got rid of it and it didn't appear in later editions. Just make sure to have equipment that works at a lower level if you're going to be throwing around spells with XP costs.


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

[User] ELI5: What are cookies from websites?

[Assistant]
A cookie is just a bit of data that the website stores on your computer to look at next time you come back.  A common and very useful application of cookies is storing what account you logged into so that you'll be signed right back in when you reopen the site.

What gets more ethically dicey is when the cookies are being used to store information about you for things like advertising (e.g. storing that you looked at X and then showing you ads about it) without your consent, which is why you see warnings about using cookies on websites.


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

[User]
Starting Computer Science Bachelors in a week, pro tips?

 enrolled in computer science because i have always been fascinated with the seemingly endless applications of the computer. I hope to one day start my own company, preferably in game design (generic, I know). Does anyone have any tips concerning my goal or the program in general, I really dont know what to expect and any advice would be appreciated. Thanks.

[Assistant]
It's very easy to learn where you stand by writing programs. Write lots of programs. Don't depend on a grade to tell you how you are doing, depend on the programs you can write.

It's a doing skill more than a knowing one.

It's a complex craft. Start now and don't stop. If you get ahead, it will make classes easier.

It's a very rewarding trade. Best of luck!


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

[User] [Harry Potter] I just got my letter to Hogwarts. Super excited, but my muggle parents don't know much about the school. Are there English, Math and Art classes in addition to the magic classes?

[Assistant]
Don't go: Hogwarts is a non credited religious school that won't teach kids any useful knowledge applicable outside their community, not unlike some Christian "universities" whose entire curriculum is reading the bible.

Good luck finding a job or entering a good university with your 'diploma'. How many Hogwarts alumni are oxford graduates? And they're also a very closed and  conservative  community  and unless your family has been doing business with wizards for a few generations, you'll be hard pressed to find a job in wizardry world. So you are looking forward to a few years of fun with spells and the rest of your life you'll be cleaning griffin shit.

The only reason the ministry of education hasn't closed their doors is because they operate outside the eyes of the law.


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

[User]
Why is fluoride good for your teeth?

Im particularly interested in any knowledge of the biochemical pathways by which fluoride strengthens teeth and fights cavities.  Its been particularly hard to find answers via google because it returns tons of pages discussing the controversy around it, but Im interested in the science.

[Assistant]
The material your teeth are made of is a type of apatite mineral. It naturally has hydroxyl groups attached to its cations, but this is very susceptible to acid attack.

Fluoride displaces the hydroxyls to convert hydroxyapatite into fluoroapatite, this is much more resistant to acid attack.


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

[User]
How do we test for the different variants of Covid? (Alpha, beta, delta, lambda, yada)

Do we look for different DNA sequences with the PCR tests, different symptoms? With all the media hammering on about the variants it would be nice to actually know how we identify these.

[Assistant]
The "Normal" PCR test for COVID-19 targets regions of the DNA that we believe are likely to be "highly conserved" ie not likely to mutate.  This has allowed us to build tests looking at things like ORF and N-Gene to identify whether what we found up your nose was in fact COVID.  Once we have a confirmed positive for a sample the remainder of the Viral Transport Medium from the swab gets split up, some is sent for sequencing and any remainder for Variant of Concern (VoC) testing.

VoC testing is PCR tests that target the actual mutations that exist in the variants.  As an example we could look for Delta by determining whether P681R is mutant (sample is Delta) or wild type (sample is not)

We can either run multiple simple PCR's one for each mutation and asses the results overall or we can run a multiplex that allows us to make our assesment off a single reaction (both methods come with their own benefits).

VoC testing is basically a way of getting a quick answer whilst genotyping gives us a slower but more details response.


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

[User]
Why is the statement "Lincoln was a Republican" technically correct, but not historically relevant/accurate?

I got into a discussion with my mother in law about the validity of the claim and I need a simple way to explain how the name "republican" used to be associated with liberalism and the "democrats" with conservatism. I don't quite understand how the switch happened either.

Edit: from what I gather, because the issues of the day were completely different, the Republican party would be considered the more liberal, or progressive party, whereas the Democrats were considered the more conservative party. As a side note, she drunkenly mentioned several times that the Democrats started the KKK. I didn't bother verifying that because it's probably true. But I couldn't make an argument for why the current members of the KKK likely line up with Tea Party, far right Republican ideals. I guess it's difficult to explain why over a hundred years of history has caused both parties to appeal to exactly the opposite types of people than they did at the time.

[Assistant]
TL;DR: It's a big tangle of racial and regional politics, and you should read the whole thing.

Technically, the Democrats and Republicans are the same parties that they were.  However, they've shifted politically, and most of that has to do with the changing nature of race in American politics.

Lincoln was a Republican, and that meant that white Southerners for several generations never forgave the Republican party for the Civil War and Reconstruction.  The Democrats could basically count on the South to always vote with them, or rather, to always vote against the republicans.  For a long time, there was a bloc in the Democratic party called the Southern Democrats that would vote mostly along party lines, but against any kind of racial integration or equal rights.  The shift of the Democrats to be more liberal/progressive was a gradual one, with the New Deal era being a pretty good milestone there.  The SDs stayed conservative and even spun off other wings like the Dixiecrats which were even more so.  The early tears in the fabric of the Democratic party can be seen at the SD walkout during the 1948 Democratic National Convention.

When the Civil Rights movement swung into gear in the 60s, the writing was on the wall for the Southern Democrats and the Democratic party in general.  After the Civil Rights act of 1964 and later the 68 one, as well as the Voting Rights act, there was no way for the SDs to reconcile anymore their party with their politics.  LBJ famously said after signing one of those (don't remember which) "Well, we just lost the South for at least a generation."  Republicans had been shifting around to become the conservative party at the same time the Dems had been moving towards the liberal end of the spectrum.  Republicans began winning in the South again as the Democrats began "betraying" the south with racial integration and SDs began to shift party affiliation.

So we move into the 70s with the Southern strategy of Nixon, capitalizing on the political shift in the South.  By playing up social issues like abortion, he was able to draw some of the last holdouts into the party; it also didn't hurt that, by this time, the last generation who had even secondhand knowledge (their parents' or grandparents' stories of their lives during the war) of the Civil War, and therefore animosity to the Republican party, were dying off.  By the time Reagan was in office, there were not really anymore Southern Democrats, as we knew them.


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

[User] How is it that batteries can provide constant voltage until theyre dead, but a capacitor slowly drops in voltage output until its dead? Why dont batteries do the same thing?

[Assistant]
Firstly, batteries are certainly not constant voltage sources. You could call them time-dependant constant voltage sources, at best. As a battery discharges, the voltage will start to drop. If you measure the voltage of a dead battery, you'll notice it is much lower than the nominal voltage.

Now, batteries provide a comparable stable voltage within a narrow range for a relatively long time, though. The main difference between batteries and capacitors in this context, is the discharge rate. A capacitor is charged with easily transferred, highly mobile charges. A battery, in contrast, has a generally higher capacity, with slower transport speeds.

You can kind of think of it like flow rate of fluids, a capacitor has a smaller tank with a larger outlet. This, it drains very quickly, and as the tank empties the flow slows. A battery will also have a continuously decreasing flow rate, but it has a longer period of time where the flow rate is still fairly close to its peak.

As far as when they die, a battery generally stops flowing charged at relatively high voltage compared to capacitors, as the affinity of the charges and electrodes of a battery is higher. With the water analogy, the outlet is near the bottom of the barrel for a capacitor, and 1/3 of the way up for the battery. Thus, the change in flow rate for the battery is less noticable before it simply stops flowing.

The analogy isn't that great if you start getting into more details, as the basic properties of capacitors and batteries differ more than two containers of water, but hopefully it gives you a basic starting point.


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

[User] ELI5:Why does my nose run when it's cold outside?

[Assistant] Our noses warm and humidify  add moisture to  the air we breathe as it travels down into the lungs. So when you inhale cold, dry air, the moist tissue inside the nose automatically increases fluid production to do its job of protecting sensitive lung tissue. But when there's too much fluid, the excess tends to drip out, creating a runny nose.


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

[User]
I need to write my PhD Thesis: Why do I feel like I'm facing a massive insurmountable wall

I need to start and finish in 3 months time or less. I have written 3 papers, one published, one in limbo other will be submitted. I find what I've done to be worth something and I've learnt and grown a lot in the last year atleast.
And yet, when I look at the past PhD thesis in my group, I find somehow that my work is lacking. I find that my glaring inadequacies staring at me, it feels like everyone has done way more than me and I'm piggybacking on other people's work and efforts.

I know I've worked so much on what I've done, but still I face this wall. Mental wall of : How the heck I'm gonna collate all the information in my head into a coherent piece of work.

How the heck I can make it look like I actually did something instead  of just dicking around for 4 years.

Can I even add enough information and learn something new to fill in all the glaring gaps in my thesis when compared to what other people have done?

I feel like a mature masters student rather than a successful PhD student.

I haven't taken a proper break in the last 6 months. I feel like taking a break is going to ruin the flow, the pace.

I am very confident in my general experimental capabilities, and yet it feels like things I've done are so unfinished, raw, confusing.

How the heck can I achieve this and smash it, is all this overthinking just some trashy imposter syndrome?

I'm just feeling a bit overwhelmed by this, i just wanna do my experiments in damn peace. How do I get over this mental barrier? Any constructive suggestins are appreciated :)

EDIT: Thank you to everyone who offered their suggestions and kind words, it has fortified my conviction a bit more. I've got this !!

[Assistant]
First off, don't compare yourself to other students. It's rarely, I'd ever, helpful.

Second, there are two things you can do to help you get momentum writing. First is to plan it out: break it down into manageable chunks, and set some goals. Then, get writing. Only focus on one thing at a time. Pace yourself, build in some rewards, maybe find other people who are writing who you can meet up and write with (many universities have thesis writing groups/bootcamps). You'll be done before you know it.


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

[User] Do animals with tracking devices have more difficulties with normal behaviors (hunting, mating, etc.)?

[Assistant] Scientists do their level best to make tracking devices and tags as unobtrusive to the animals daily lives as possible, and for the most part they succeed. You still end up with the occasional case like the ornithologist who banded a couple birds with red leg bands that were apparently so sexy to females of the same species that it threw off the data for the entire study.


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

[User]
If we could travel far enough, could we retrieve the entirety of human radio and television broadcasts?

Are there any other theoretical ways in which we could retrieve them?

[Assistant]
Not really - you can't travel faster than light, so you'll never "catch up" to past broadcasts.

If you had a magic teleportation machine - or, less impossibly, some aliens had set up a series of antennae several light-years away - then yes, you could in principle pick up broadcasts from the past.

However, in practice, TV and radio broadcasts spread out over space and become weaker, and would be lost below the noise threshold well before a light-year of distance. To communicate with probes on Mars requires special targetted equipment, and that's only light-minutes away. For programmes like SETI, people aren't looking for leaked radio signals - they're looking for intentional beacons sent by alien civilizations.


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

[User] [DC] I'm a super villain contractor currently based out of Gotham. What kind of terms and conditions should I work with my villains to make sure my business and I stay alive? Any clients I should avoid?

[Assistant]
Terms and conditions? Lol.

You (or your organization) simply needs to be strong enough that trying to betray you isn't worth the effort. Now that could be because you are super powered yourself, or maybe because your subcontractors also double as mercenaries.

You're working in the criminal underworld with some of the most devious people around, the only term or condition most of them will respect is "don't fuck with me or I'll fuck with you worse."


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

[User] ELI5: after eating, we have to brush our teeth to stop our teeth getting eaten from bacteria, right? So where does the bacteria come from, if we get rid of them every day?

[Assistant]
Bacteria are always present in your mouth, and brushing your teeth doesn't do anything to reduce their population.

What brushing does is scrape off the bacterial colonies that build up on your teeth as plaques, reducing the damage their acidic secretions can do to your enamel.


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

[User]
Why is death irreversible?

Not sure which subreddit this is most appropriate for. What if someone dies at a relatively young age, lets say, due to some kind of heart failure.(if another type of death is easier you can use that) Why can't they just replace the broken part(s) and bring them back to life? (assuming you didnt wait for the rest of the body to deteriorate)

[Assistant]
Once youre heart stops in your example, the blood stops going to the brain and other vital organs. With no oxygen the cells begin to change their metabolism, and within a few minutes cease to create any ATP at all. ( ATP = molecule used as basic energy currency by the body )

Without ATP to power their transmembrane pump, they cant maintain any of their chemical gradients  all the ions start to dissipate, ruining the precious electrochemical balance and alot of reactions  cease - as do the ATP dependent reactions. This damage is pretty irreversible.

Returning blood flow to organs like that usually does either nothing, or flushes all the leaked ions and chemicals away, which then can rush to the kidney and can damage it pretty severely ( this is called reperfusion injury )

Of course, your kidney would be in bits too so thats not a bit deal, and the blood would probably be clotted and the cells lysed also, so thats a factor.

Im sure that theoretically you could reverse one little aspect of cellular damage, but theyre 100's and it all happens very fast, and all at once.


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

[User]
Why are the undersides of our nails rough?

When you clip your nails, the underside is extremely rough, almost like sandpaper. The top however, is smooth. I was under the impression that the nails exist because of the sensitive skin, so wouldn't this rough texture irritate it more?

[Assistant]
Your nails are "built" that way on both sides, but during the months of time it takes for the nail to grow out, the top is constantly exposed, and essentially gets sanded down.

The bottom is not, and is essentially adhered to the skin underneath the whole time.


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

[User]
[Star Wars] How did the Jedi morally justify using living clones as an army? Shouldn't they have been the side to use droids?

These clones were made to fight and die. They essentially were breeding pit bulls for dog fighting, which is really scummy.

When the Death Star blows up Alderaan, Obi-Wan can feel the millions of people dying. Their pain and screams are enough to reach him. It seems like any peace loving group of people would hate the idea of artificially creating life to make them soldiers in a war. Also- didn't the Jedi want to bring balance to the force? Seems like mass-producing humans would mess up that balance in a big way.

Was there any explanation of this? Or was any Jedi publicly against the idea?

[Assistant]
Forcing the Jedi to ethically compromise themselves was all part of the purpose of the war. The cognitive dissonance of which you speak was a contributing factor to the unusual number of Jedi that fell to the Dark Side or left the order during the Clone Wars.

>Also- didn't the Jedi want to bring balance to the force? Seems like mass-producing humans would mess up that balance in a big way.

Yes and no. Balance in the Force doesn't mean quite what you think. The Dark Side, especially as practiced by the Sith, is the source of the imbalance. So yes, the clones were the result of the machinations of a powerful Sith Lord, but like all living creatures they were themselves simply a manifestation of the Force.


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

[User]
Galaxies are hundreds of thousands of lightyears in diameter, and gravity only travels with the speed of light. Does this not distort the shape of them?

Or is this the reason for that galaxies have "arms"?

[Assistant]
The Sun's orbit around the galaxy needs about 250 million years and the overall mass has been there for billions of years.

Tens of thousands of years are simply negligible on the timescale of galaxies.


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

[User]
Does time dilation at the speed of light also mean that distance collapses to zero?

So the nearest star outside our solar system is roughly 4 light years away.

A photon generated by that star, from our reference point, would take 4 years to reach earth.

From the point of reference of the photon which is obviously travelling at the speed of light, time dilation has caused time to completely stop, so the "*4 light year*" trip occurs instantaneously.

Because the photon can not violate relativity and surpass the speed of light, it appears that the only other way the photon could have instantly traveled 4 light years (or **any** distance), is if the distance was **also** zero.

My (very limited) understanding is that length contraction, in this example, only occurs for observers of the photon, but not the photon itself. So from our reference point on earth, the length of the photon in the direction of travel, contracts to zero (or near zero), but this does not occur at all to the photon, from the photon's point of reference, and does not affect the distance traveled by the photon.

What am I missing that explains how the photon can travel 4 light years distance in zero time ?

I've created my Reddit account just to ask this question, so many thanks to anyone taking the time to respond to this.

[Assistant] Photons don't have a reference frame. One of the laws of relativity states that from every perspective, light always travels at c. If you're a photon, then you will observe yourself staying still, rather than travelling at c, which violates this rule of relativity and outlaws photon reference frames.


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

[User]
I just got an email from journal editor asking for full paper of my conference poster for publication. Is this an honor or scam?

I have little experience with publishing. I know it costs to publish so I'm sure there are journals out there that just want people's money. I have not heard of journals contacting researchers like this. Does anyone know any thing about Universal Journal of Psychology? I have never heard of them.

Plus, I only made a poster because my group needed to do additional experiments. I moved and the project fell to the wayside. I could contact the professors I worked with and we may be able to put something together. Do you think the journal would be willing to wait?

Edit: thanks everyone for the info!

[Assistant]
Scam scam scam.

No reputable journal solicits for articles from conference abstracts in the distant past. Furthermore, this is published by Horizon Research who - along with their other journals - all make Beall's list of predatory publishers.


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

[User]
ELI5: How do we think about moving our body without actually moving it?

What's the difference between thinking about, say, moving your arm and actually doing it? What makes the first one just a thought, and the second one a decision + movement? Thanks in advance, sorry if it's a stupid question.

EDIT: Wow, thanks for all the awards and great answers :)

[Assistant]
Basically, whether or not the signal gets sent from your brain to the limb.  Interestingly, a lot of the brain activity in the brain is similar when we think about something as when we do it.  Might seem kinda obvious, but it goes deeper than you think.  If you scan a musician's brain when they actively listen to music, it will light up in a similar way as when they are *playing* the music.  This is different from someone who doesn't play an instrument listening to it.  Or when you listen to someone speaking, part of your understanding comes from imagining yourself making those sounds, and working out what words you'd be saying if you did that.  This is why you see some people mouthing along as they listen to someone speaking.

Edit: thanks, kind strangers.  Hopefully you meant to actually press the award button, rather than just *thinking* about it...


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

[User]
ELI5: How can the US have debts and still be considered as the richest country in the world?

Currently we have over $16 trillion national debts. At the same time, we are also the richest country in the world based on GDP.

[Assistant]
GDP doesn't take account of government debt. It is solely related to output. For instance, a car company buys steel and adds value to that steel by shaping it into a car. That steel is now worth more per kilo than it was before (value has been added) because it's been turned into something more than just the raw material. That *added value* is what constitutes GDP. Not overall sales, but the amount of stuff the country *produces*.

The USA has the biggest economy in the world and the largest GDP.

However, not everyone would call the country with the highest GDP the "richest" country. That is very much more subjective and depends on what you value as an indicator of "rich".

After America, China has the next largest GDP, but few would consider China to be "a rich country" when you look at GDP *per capita*. BY GDP per capita, the USA comes between 9th and 14th depending on who's measure of GDP you use.

That list is topped by countries like Luxembourg and Monaco where a lot of companies are based for tax purposes but which have a relatively small population. As a result these countries tend to have a lot of money to spend per capita and enjoy a good quality of life - despite not having the largest GDP, by some measures you would say *they* were the richest.


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

[User] ELI5: How do birds detect that there's bread scattered around my garden, and that the nut feeder hidden out of view is full?

[Assistant] Birds care about food a great deal. It's their equivalent of profession to find food. If you provide food for birds often they probably take notice of this fact rather than the individual feedings. Therefore they know to check regularly whether there is food and indeed don't know beforehand if there is. Presumably they will check for food even when it is not there, but you won't take special note of this because you are not there to see it.


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

[User] ELI5: Why does it take a few days to get DNA tests complete for the NY escaped convicts but it takes months to get DNA results in sex crime investigations?

[Assistant] It's just a matter of prioritization. For the backed-up case load it wouldn't make sense to do the new one first. But the escaped fugitives are a priority so they push it to the front of the line. The tests don't actually take long.


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

[User]
[Stargate SG-1] Why didn't the US military loot as many Ha'tak Class motherships as possible after the Goa'uld Empire fell?

I really find it hard to believe that the US did not jump at the opportunity to easily expand their military and force-projection capabilities 1 million fold.

* By that time, the Tau'ri only had the Prometheus, and were just beginning to construct BC-304s. The US military lacked a space fleet, and using Ha'taks were a great way to supplement their fledgling fleet early on.

* While BC-304s were slightly superior to Ha'taks, one Ha'tak still had more firepower than pretty much everything else in the US military arsenal.

* Nukes and even less powerful weaponry used by the US military were incredibly expensive to make and fire, while Hat'ak energy blasts (200 megatons) were almost free.

* Ha'taks apparently can be piloted with very minimal training and crew. A single SG-team was enough to capture a Mothership.

* There was a very abundant number of them scattered across the galaxy, and the US military by itself likely outnumbered the rogue elements that filled the power vacuum after the Goa'uld Empire fell.

* Taking as many Motherships as possible would have denied their use to groups like the Lucian Alliance, or Goa'uld remnants. An agreement with the Free Jaffa Nation could be made to fairly split the spoils of war.

[Assistant] They did a bit but it's not like they had 411 on ships and anyone who was in one and not dead most likely flew it home or to the nearest power filling the vaccume. Also the US military is not 100% free to do whatever they want through the ring. Other countries have stake too and the tech that we take aside from small arms is largely mechanics and medical. This isn't a prefect answer but seems reasonable.


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

[User]
ELI5: How do cysts form?

I am aware that there are forms of cysts.

So why is it trauma to an area causes the body to create a "sack" instead of just pus (white blood cells?)  in some cases. And if it is a sack, how does it fill up from the inside and then grow and grow to the point it protrudes?

[Assistant] There are many examples of cysts as you stated, but here are a couple. A bakers cyst forms behind the knee any time there is an injury or condition in the knee causing an inflammatory reaction leading to increased synovial fluid production. The rear of the knee is just the least structurally stout area so that is where the fluid tends to collect. A ganglion cyst usually forms due to a weak spot in a tendon sheath like a weak spot in an inner tube. The fluid in the sheath tends to inflate the weak spot, then stagnate and gelatinize forming the cyst. Bones can have an infarct or other condition that can cause an area of medullary bone death that is typically walled off by the body and then a cyst forms in the void. There are many more but these are a few.


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

[User]
ELI5: What is actually done to a PS3 game like Uncharted when it's "remastered" for PS4?

Does the entire thing have to be "reprogrammed" from scratch?

[Assistant]
Not typically. More often they'll take the original codebase, update the models with nicer ones, maybe touchup bugs or well-knowni issues, maybe work on the lighting or rendering to make it look nicer, etc.

It can certainly be a large undertaking, but it's by no means as big of an effort as a full code re-write.


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

[User] ELI5: Why is it a reaction to "shake off" our hands after we slam or jam our fingers?

[Assistant]
One: Distraction - adding stimuli and movement helps to reduce the feeling of pain.

Two: Protection - the cause of the pain isn't exactly understood by your brain, so it starts an immediate reaction to deal with it. Some painful stimuli (hot liquids, acids, biting insects) can be flung away.

Three: Adrenaline - pain stimulates adrenaline, which gets your body wanting to move.

Four: Blood flow - Injuries can cause blood to pool, shaking your hands will help with blood flow and stop some of the pooling which can cause secondary damage.


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

[User] ELI5: Why does a GIF with the same exact frames as a video file a lot bigger in size (like 4MB mp4 is even a 200MB gif)? Is it something to do with video compression?

[Assistant] Yes, a gif contains every pixel of every frame. A video format generally contains only the difference between most back to back frames, with a fraction of the frames fully stored. The ratios and how its done will vary between formats, but yes it that video formats have better compression.


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

[User]
ELI5: If the odds of winning a $600 million mega jackpot are say 200 million to 1, why wouldn't a billionaire buy 200 million tickets, win the jackpot and profit $400 million?

EDIT: I know about taxes, I know it's not practical, I know the odds, I know billionaires can spend their money better elsewhere, I know others can win, I just wanted to hear a clear cut answer!

[Assistant]
200 million to one is the odds of getting the right ticket. However the right ticket can be purchased several times. As such you could wind up spending 200 million and only getting 50 million (taxes suck). Further, they take more taxes if you choose the lump sum payment vs. the 20 year payouts.

To put it in perspective, the recent 658 million jackpot was won by two people both of whom took the lump sum payout. After taxes they each get 158 million. Still a lot of money, but not if you paid 200 million for the ticket.

There are better things to invest your money in if you are a billionaire.