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

[User]
Why do multiples of 9, always come back to 9 when their digits are added together?

Sorry I could have probably worded the title better.

I remember my second grade teacher taught me this but never explained why she just said it was a a magic number lol.

Example:

9*2=18,  1+8=9

9*3=27,  2+7=9

9*4=36,  3+6=9

etc, etc, etc.....,

Of course there are many interesting recurrences with small number and wen we learned our multiplication tables as kids,  but this trend seems to stay the same even as the number you multiply by 9 increase.  Even with random numbers in the tens and hundreds similar pattern.

Example

9*53=477,  4+7+7=18,   1+8=9

9*87=783,  7+8+3=18,   1+8=9

9*681=6129, 6+1+2+9=18,   1+8=9

9*217=1953, 1+9+5+3=18,   1+8=9

Now I've only used  positive integers,  haven't even looked into negatives, nor decimals, nor any other parameters so to speak.  Are there any exceptions doing this with positive integers? And why does this work?  This is a smart sub and I'm sure the answer is simple but I've just always been curious about it.  I'll try a few more larger random  numbers with greater number of digits.

9*876,257=7,886,313 :

7+8+8+6+3+1+3=36,    3+6=9

One more even larger number

9*12,345,678=111,111,102   :

1+1+1+1+1+1+1+0+2=9

Are there any other weird happenstances like this?  if so please elaborate...

[Assistant]
To see why this works, we first have to start with how a number, when written down, is constructed.

Take the number 123. This notation means: 1 * 100 + 2 * 10 + 3 * 1. To deconstruct a number in this way, you take a digit and multiply it by the power of 10 appropriate for the position of that digit within the number.

Now we make a brief detour through the realms of divisibility and remainders. Note that we only work with integers, so no decimals or funny stuff behind the period. When we divide something like 52 / 9, we can fit 9 a total of 5 times and are left with a remainder of 7. So we can write:

52 / 9 = 5

but also

52 % 9 = 7

The %-sign is often used for the function that gives you the remainder in a certain division. This function is called the modulo function. If a number fully divides another number, the remainder will be zero:

18 % 9 = 0 (this says: The remainder when dividing 18 by 9 is 0)

Now, the modulo function has some nice properties. One of which is that it is distributive with addition and multiplication. What does this mean? It means that if we have an expression like (a + b) % c (or: the remainder of (a + b) when divided by c), then that's the same as a % c + b % c (or: the remainder of a when divided by c plus the remainder of b when divided by c). The same holds when you replace the addition-operation by multiplicaiton.

Now, lets put the pieces together. First we look at the remainder of a few numbers when divided by 9:

1 % 9 = 1

10 % 9 = 1 (10 divided by 9 is 1 with remainder 1)

100 % 9 = 1 (100 divided by 9 is 11 with remainder 1)

1000 % 9 = 1 (1000 divided by 9 is 111 with remainder 1)

Notice a pattern?

If we have a number of the form abcd, then from the first section we know that this can be written as:

a * 1000 + b * 100 + c * 10 + d * 1

So if we want to see what the remainder of this number is when divided by 9, we can use the properties of the modulo function:

abcd % 9 = (a * 1000 + b * 100 + c * 10 + d * 1) % 9 = (a * 1000) % 9 + (b * 100) % 9 + (c * 10) % 9 + (d * 1) % 9

Each term can be rewritten as:

(a % 9) * (1000 % 9)

Since we know that a power of 10 has remainder 1 when divided by 9, these factors drop out and we're left with:

(a % 9) + (b % 9) + (c % 9) + (d % 9)

Once again applying the distributivity of the modulo function:

(a + b + c + d) % 9

So the final conclusion is that the remainder of a number when divided by 9 is equal to the remainder of the sum of the digits of the number when divided by 9. More specifically, if a number is fully divisible by 9 (so remainder 0), then the sum of its digits is too.

In some cases, the sum of the digits will be a number consisting of multiple digits. In that case, you can reapply the same reasoning to the sum of the digits of the sum of the digits. And repeat this process until you end up with a one digit number that is divisible by 9. And which one digit numbers are divisible by 9? Just one, 9 itself.

So a general conclusion is that if a number is divisble by 9, then the repeated summing of its digits in this way will always end up with a 9. And, to check if a number is divisible by 9, you can add up its digits and check if that value is divisible by 9. If that value is still to big to quickly check, you can repeat the process.

Note: There is a similar property when dividing by 3: A number is divisible by 3 if and only if the sum of its digits are divisible by 3. The proof of this statement follows the same reasoning as for division by 9.

Finally, homework for the interested reader: There's a similar, but slightly more involved trick to determine whether a number is divisible by 11. Find it and prove it :-)


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

[User]
[MCU/Raimiverse] Why the hell does green goblin despise Spider-Man so much?

Him killing his coworkers and the board for wronging him I understand but Tom Holland's Peter did absolutely nothing to him. Hell I can understand him hating raimi Spider-Man because he foils goblins plan, but Tom Holland's literally has done nothing to wrong him.

[Assistant]
Well Peter 1 tried to cure him, which is definitely an affront to him.

But the main thing about the Green Goblin is that he has a ideology about doing whatever he wants with his power. He used it to make Norman's life better and he told Peter 2 that they could rule New York together. He also goes on to talk about how he is a God.

He is basically the anti-Spider-Man in that he believes that his power should be used to get whatever he wants when he wants. The fact that Peter would use his abilities to help others altrustically is in and of itself an affront to him.

When he found himself in a new universe to him nothing has changed. Peter is still wasting his powers from his perspective so he wants to show him the proper way (>!which he attempts by killing May to free him of moral shackles!<) or he kills him for daring to play the hero.

Aside from following a vague ideology he doesn't really have a Super deep reason for doing what he does. He knows Peter would stand in his way be it now or later so he just struck first. At the heart like he tends to. And the also seems content with ideological victory as being killed by Peter seemed like something he was fine with as it just proved his point.


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

[User] ELI5: Why do I get a metallic taste in my mouth and a fuzzy ache in my head and hands after a nap, but not a full night of sleep?

[Assistant]
Those are two different things.

The metallic taste is bacteria growing in your mouth. (Nice huh.) You don't get it during the day because you regularly swallow, and you generally don't get it overnight because brushing your teeth kills off a lot of the bacteria.

If you brush your teeth before a nap (especially use mouthwash) you'll avoid the mouth gunk.


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

[User]
[Star Wars] Why didnt Count Dooku use Force Lightning in his final duel?

In The Clone Wars series, Dooku is consistently shown to use his Force Lightning as a last resort to defeat his enemies. Notable examples are in his duels against Asajj Ventress, Savage Oppress, and even Anakin on Nabooin each case he was seemingly on the verge it defeat before turning the tide with the Lightning. Assuming that the Lightning is as effective, why didnt Dooku use it in his duel with Obi-Wan and Anakin over Corusaunt? Did he simply not get the chance to?

[Assistant]
>Did he simply not get the chance to?

This is probably it, Anakin was pressing him hard and by tapping into his Chosen One potential and inner rage he could finally overpower Dooku with his superior strength. Anakin didn't give him the chance before cutting his hands off and having sabers at his neck.

Doubt it's a matter of Lightning being too draining, he's used it at worse times (being blinded and beaten down by Nightsisters).


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

[User]
ELI5: Difference between functions and procedures in C++?

Is it okay to say that in C++ all procedures are void, and all the rest (whatever returns a value) is a function?

[Assistant]
Procedures and functions are pretty much interchangeable terms. The proper C++ terminology is "function", and the term "procedure" isn't used (a function which has a void return type is still a function).

Other languages (like Pascal) differentiate between procedure and function, just like you asked.


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

[User] ELI5: WTF is the number after classes in the US? Informatics 101, etc.

[Assistant]
100 and 200 level class are general education and introductary classes to a subject.  Usually they can be taken by anyone regardless of major.

300 and 400 level classes are more advanced classes and are generally only for the people who are involved in a major for those classes.

All 100 to 400 level classes are for undergrads

500 and 600 level classes are for graduate students.

700 and above are usually for doctoral candidates and some grad students.

The number after the hundreds, such as 101, or 102. Just designates a specific number for the class, and many schools treat it differently. Usually a 101 class is the first class (or basic class) in any subject.

Sometimes classes are in a sequence as well, such as 351 and 352. As  in it may say MATH 351 Algebra, then MATH 352 Algebra 2.


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

[User] [MARVEL]How did J Jonah Jameson react when Peter revealed himself as Spider-Man?

[Assistant]
The first time, during Civil War, he fainted. When he fully processed it he had a bigger vendetta for Spider-Man than ever before. He felt completely humiliated that all those years Spider-Man was right under his nose.

The second time, in Spectacular Spider-Man, Peter and Jameson had a closer relationship than they did back in Civil War, they are pretty much cousins through Aunt May and Jay Jameson's marriage. When Spider-Man revealed his secret to Jameson, he had pretty much the opposite reaction. He was much more understanding and he decided Spider-Man was in need of his expertise. Jameson is now Spider-Man's "man in the chair," though he isn't very good at it and typically bickers with Peter more than he helps him.


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

[User]
[Spider-Man] So...is there a racist Spider-Man out there in the multiverse somewhere?

Weird question I know, but please hear me out.

I saw a post of a discussion between two Spider-Men from different multiverses, from a multiverse event presumably.

One Spidey questions that their are two Japanese Spidey's, to which the other replies "Why not?" The first Spidey says "Oh no. I hope I'm not *racist* Spider-Man."

That got me thinking. There's pig Spider-Man, 1940's Noir Spider-Man (who, as far as I know, isn't racist), little asian girl Spider-Man, etc.

In the vast multiverse of Spider-Men, *is* there a racist Spider-Man? Like from an alternate history where the Nazis won or something?

I'm talking mostly Peter Parkers and/or variants of Peter, but I accept any (dis)honorable mentions.

Edit: Who the fuck gave this a wholesome award?

[Assistant]
Well, look at it this way. There are an infinite number of even numbers, each one unique. But none of those even numbers will ever end in an odd number.

Spider-Gwen is *definitely* not Spider-*Man*. Neither is Peter Porker, whose Spider-*Ham* conjures an uncomfortable awareness of how a character identifies as meat.

An infinite number of people get bitten by a radioactive spider and develop powers. Not all of them are Spider-Man. Depending on how you define Spider-Man, you can exclude der Spinne (Nazi universe) and Crawly-Boy (Confederate universe).


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

[User] ELI5: Why does slapping it actually makes tv remotes work again?

[Assistant]
The battery has a cheap metal contact head which is different from the remote not-so-cheap copper contact. The two metal will do what is called galvanic corrosion.

microscopically, there is a thin layer of oxide on your contacts and when the battery is almost dead, that little barrier will be comparatively too much. This is more noticeable on low power devices like remotes, mouse, keyboards. A high power device will just eat the whole battery no matter what.

When you hit the remote the battery shakes inside and the movement will slide the contacts and clean off the microscopic oxide.

On at her devices the battery is installed too tight to allow this trick work, not remove and reinstall the battery will do the same effect.

The battery is almost dead so this action is just delaying the inevitable.


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

[User]
ELI5: Why do people have to send a message saying that they are going in war instead of just directly attacking?

Like the title suggest, why would a county declare an attack on a enemy instead of just going directly for an attack without letting the enemy know?

Wouldn't it give them more chance to win the war?

[Assistant] This might not directly answer what you are asking, but countries simply don't declare war anymore. There are definitely still many conflicts, but most involve "unofficial" organizations such as terrorist groups that don't require a formal declaration of war to attack. It is rare now to have one country directly invade another country, and if it does, there are usually loopholes that are exploited to "declare war" without actually declaring war. There's no real easily accessible "list" of declarations of war that I've found, but IIRC no war has been officially declared since the Six-Day War.


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

[User]
ELI5: Is a pregnant mother's blood kept separate from her fetus' blood?

I have searched online multiple times to see whether a pregnant mother's blood and her fetus' blood are kept separate. I've even looked in textbooks, and often it's implied but never said outright and plainly in those terms.

I've looked online, but I've not yet found a reputable source that spells it out clearly.

Are a pregnant mother's blood and her fetus' blood kept separate? Why or why not?

[Assistant]
There is a placental blood barrier, yes.

> One of the placenta's jobs is to make sure blood from the mother and fetus never mixes. The placenta acts as an exchange surface between the mother and the fetus. Nutrients and oxygen are passed over by diffusion only. If the mother's and fetus's blood mixed, it could be deadly for both of them. If the mother and the fetus had different blood types, they might both die if their blood mixed.

Wikipedia.


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

[User] When Giving CPR, How Are You Not Just Blowing CO2 Right Into Some Dying Dude's Lungs?

[Assistant] We inhale 21% oxygen from the air, and exhale 18% oxygen. We use very little of the O2 we actually breathe in, so we still exhale quite a bit of oxygen. We have to breathe more frequently mostly to get rid of excess CO2. Rescue breaths are definitely sub-optimal, because of the CO2 concentrations that can build up, but it is better than not receiving any oxygen at all.


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

[User]
helicopters have rear rotors to control spin, why don't single prop planes need to control roll?

I get that the rotational torque of a helicopter's main rotor needs to be offset to prevent it the body from spinning in place--and that is what the rear rotor is for, makes sense. But in the case of a single propeller plane, why doesn't it need some smaller prop/rotor at the wingtips to help with the rotational force that would make it roll?

[Assistant] Small single engine aircraft DO in fact have torque-based roll and thus turning tendencies.  However the wings and flight control trim counter roll and rudder trim counteracts turn tendencies.  The mass and surface area of the prop compared to the mass and area of the aircraft is a much smaller ratio.


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

[User] When a Pistol Shrimp snaps its claw and forms a cavitation bubble, what forms in the bubble? Does the air have normal gas concentrations or is it something altogether different?

[Assistant] A cavitation bubble is basically a void in the liquid. The key thing that defines the void is that it is free of liquid. Beyond that, the specifics will depend on how exactly you formed the bubble, but in general consist of some concentration of vapor. Because liquid water wants to rush back in, these voids rapidly fill back up in a violent way with local temperatures reaching multiple thousands of degree Celsius.


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

[User] ELI5: How can congress stay in office for so long and be reelected regularly when approval ratings is so low.

[Assistant]
Because everyone has the tendency to say that it's everyone ELSE'S representative who sucks, but tend to believe that theirs is okay.

Also, because when the election comes up, it turns out people's party allegiance is way stronger than their hatred for Congress.  So even if they despise their representative, they'll still vote them in before "the other guy."


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

[User]
Apply for PhD Programs or Stay in Research Lab for 1 Extra Year?

So I'm a post bac student (5 years research experience) who just got hired on a grant to do research on Suicide Prevention & PTSD. My job appointment is 1 year, but can be extended longer if agreed by me and my boss (who relocated from out of state)

My dilemma: Should I go/apply to grad school for Clinical Psychology next fall (1 Year from now) or stay for 2 years and build the lab up?

My current boss said (after she hired me btw) that she's looking to hire more people on grants who want to stay for the experience/to build the lab and not just to get publications to slap something on their resume. She said if someone stays for 2 years they'll "practically have a dissertation".

I want both genuine experience and publications to show my growth and effort. But I'm also ready to go to grad school (I'm 25) now

Would you stay and build the lab, or take 1 year experience then go to grad school?

All thoughts and advice are appreciated!

EDIT: Clinical Psych PhD Programs
EDIT2: I graduated in 2014 and have 5 years research experience.

[Assistant] You staying in the lab to build it is really going to benefit your boss more than you. If your goal is to get a psych PhD you should apply to programs as soon as you can. If you get into a program you like you should go.


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

[User]
ELI5 Why people find beer delicious and refreshing.

Honestly I think it's all a conspiracy. I believe every single one of you actually thinks beer tastes disgusting, but since everyone else has a reason to love it, you do too. How do you come up with all these sophistacted adjectives to describe it. I have tried dozens and dozens of different beers. None of them have ever been refreshing or full bodied or "bursting with summer flavors."

Some people tell me "it's an acquired taste." To me, that just means you have to suffer through it until you don't care anymore and I don't really see it as an explanation. But to find delicious and refreshing and decadent flavors in that liquid just doesn't make sense to me.

EDIT: Not trying to say that having a vagina means you don't like beer. I know plenty of females who love it. According to my beer-brewing roommates, however, there's a good chance that that's my problem. xD

TL;DR - What is it about beer that you find so refreshing and yummy? What does it for you?
Maybe it's because I have a vagina. I don't know. Explain this shit.

[Assistant] It's similar to strong black coffee, protein shakes, liver, and many more bitter or strong tasting foods and liquids, you have to get acclimated to the taste before you can recognize the small subtleties in flavor and texture.


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

[User]
ELI5: why would a landlord rent control an apartment?

If a landlord owns an apartment in say New York, why would they offer rent control when they could just raise the price of rent year over year and make more money?

[Assistant]
Rent control is a state mandated option for people who are qualified under welfare care laws and regulations to ensure that people can afford housing.

Rent control and EHO homes are reserved pricing structures for what the tenant can afford to pay under what the laws deem appropriate.


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

[User]
[Game of Thrones] What if Aemon Targaryen became the king. (Spoilers)

So what if Aemon took up his duty as the king and left the nights watch. Assuming he faced no repercussions for leaving the watch, how would things be different if he was the king and not the Mad King. Would Lyanna Stark still been taken by rhaegar targaryen?

[Assistant]
Even the very wise cannot begin to fathom the twist and turns of fate.  Perhaps Aemon would've failed to have children or they would have died early and the throne would have passed to Egg regardless.

Perhaps the tragedy at Summerhall wouldn't have happened, or maybe it would anyways.

I will tell you this.  We once had an heir.  Prince Baelor Breakspear.  Bloody good man he was.  Set to become King, and a great one.  Then one day he stands up for a Hedge Knight in a tournament against his kin and his brother smashes his skull open with a mace.  He left a son, but his son died in the great spring sickness and his sons were stillborn.  His entire lineage was wiped, despite being so strong and sure, and the throne passed to a lesser branch of House Targaryen.

Perhaps much would've changed, perhaps nothing.  Perhaps Aemon would've become a bad king, as the Throne was offered to him when he was largely in his youth as a Maester, before he took the Black.  He took the Black explicitly to keep them from offering the Throne to him again.

People who know Aemon would say he was a good man, and by some definitions that means he would be a good King, but there's no certainty but death and winter.


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

[User]
[Lovecraftian Mythos] Who is the top creature in the Lovecraftian mythos?

 I recently started learning a little more about the creatures in the Lovecraftian universe and I'm curious as to who the most powerful creature in the universe would be? Cthulhu seems to be the most well known, but is there an all powerful king type creature?

[Assistant]
That would be Azathoth, the "Blind God Idiot", who holds his court at the center of infinity and dreams up the universe despite not actively being aware of the fact that he is doing so.

A popular interpretation is that you re Azathoth, and that in reading Lovecraft's works you are bringing the universe and the other Outer and Elder gods into being.


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

[User]
How does a "blood pressure" manometer measure the preasure of your blood?

The manometer cuff pressure plus atmospheric pressure is measured, and the cuff pressure is a response from squeezing your arm. By that logic, aren't we measuring the pressure of your arm as a whole (including other fluids/water, muscles, etc.)?

[Assistant]
Blood pressure cuffs register three states when they activate.

First, they inflate to full, closing off the artery completely. Then they deflate slowly until it detects that blood flow is resumed, the point where your blood pressure is greater than the pressure of the cuff is your Systolic Pressure. Then it deflates further until the blood vessels have expanded to full, and no longer vibrate the cuff. The remaining air pressure in the cuff is considered your Diastolic Pressure.

In short, it is mostly checking your arm for vibrations caused by the abnormal blood flow caused by squeezing the arteries.


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

[User] ELI5:While on a phone call, how can you hear sounds like an alarm but the other person on the other line is unable to?

[Assistant]
Newer phones use noise cancelling which is very good at rejecting sounds that don't come from directly in front of the phone's mic (where your mouth is).

Alarm sounds (I assume based on your premise) are coming from farther away and aren't pointed directly into the mic. Us sound guys call that "off axis".


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

[User]
[Dune] So, the Spacing Guild needs Spice for humanity to utilize FTL travel. Spice comes from Sand Worms. Sand Worms are only native to Arrakis. So how did we get to Arrakis?

It's been some years since I've read the series and so I apologize if this was covered... but as I lie in bed unable to sleep, for whatever reason *this* is the question my mind is pondering over.

[Assistant]
Before reaching Arrakis there was "conventional" FTL travel. This system has been described as "outracing photons" and these ships used computers to deal with navigational issues. They were much slower than the later ships who had navigators and used spacefolding. Spacefolding ships *were* possible with computers, but were not 100% safe, leading to the loss of ships.

With the discovery of spice, spacefolding ships that used a practical application of the "Holtzman Effect" became possible and reliable.  Plotting a safe course through space folds was done by using a navigator who could presciently see into the future (by ingesting the spice) and plan the course which would keep the ship safe.

Space folding was far faster and so it became the primary form of travel until later on navigation machines were created that were able to be as good as spice fuelled navigators which eventually broke the the guild's monopoly on space travel.


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

[User] Despite the diversity of life, no form has three sexes. Why exactly?

[Assistant]
I took a class on the evolution of reproduction. We actually do see multiple sexes (mating types) in certain species like Physarium (a genus of slime mould) which has >500 sexes (but it still only takes two individuals, who are not the same sex, to make a baby).

The main problem that limits most species to 2 sexes is the issue of mitochondrial inheritance. Basically, when the two gametes fuse, only one of them can donate its mitochondria (if they both did, the cell would die). So, nature's solution was to create two general mating types: Male (DNA only donors) and Female (DNA and mitochondria donors).

In most species with multiple sexes, the mitochondria donor seems to be determined by a "rock-paper-scissors"-type of game.


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

[User]
ELI5: How come game engines like Unreal and Unity can render high fidelity graphics in real time but rendering a scene using actual movie software takes forever?

I'm aware that a lot of companies are now using those very tools to make their movies and shows because of that very reason but why does it work out that way?

[Assistant] Real-time graphics use lots of shortcuts, which are less accurate but look "good enough" at first glance.  For example: most videogame engines cannot render reflections (if you do play a game with a functioning mirror, it's typically accomplished by placing a second copy of the room behind the mirror, with everything in it the same).  They "fake" reflections by just making shiny and dim parts of an object, but they aren't real reflections.  Movies do the diligence and every shiny object is properly reflecting its surroundings.


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

[User]
Would Darwin be a moral naturalist?

His following qoute is often recycled, that goes something like, 'had we been reared under the conditions of hive bees.. we would think it moral to do x'
The point is, it seems to me, that something about our inherited nature constrains or determines what is moral for a being like us. So, would Darwin have taken this to mean that we ought to be anti-realists - because moral goodness is fixed to our nature and since nature could have been anything, so could have our concept of goodness been anything - OR would this be a kind of mind-independent natural fact - it is true by definition that we moral goodness is X for beings like Y, and X is therefore true independently of Y.

[Assistant] Moral realism is the position that moral sentences express propositions that refer to objective features of the world. Darwin's observations about where our moral beliefs come from have no bearing on whether moral realism is true or not. This is because an explanation of why someone believes X is not the same as an explanation of why X is (or is not) true.


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

[User]
If you receive a life-threatening injury, does
maintaining consciousness as people rush to get aid
really help?

You often see in the movies someone saying "stay with me buddy!" or hear about non-movie situations where people say the same: "don't fall asleep," or "keep looking at me" because if they don't, they may die.

Why is it that staying conscious should help you stay alive? What's going on in the body? Can the conscious brain, through some sort of exertion of will, give commands to your body that keep it from shutting down, that it couldn't otherwise give when you are unconscious?

[Assistant] Another reason why they prefer a person stay awake is to get any vital information that may be required. An unconscious person will have a harder time explaining where it hurts than someone who is awake. Sometimes they may also need to identify a poisonous creature that may have injected venom in them.


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

[User]
ELI5: why don't hockey teams hire a 500 lb. goalie to block the whole goal?

Title says it all. Why don't professional hockey teams just hire a massive dude to block the whole goal to win every game?

[Assistant]
There is a sports science episode covering this.

It basically boils down to 1)It does not cover the whole net. And with the assumption that a 500lb guy isn't too athletic, the open part of the net will just be free goals.

Also regulation sized protective equipement does not cover a 500lb man.


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

[User]
ELI5: Where do uploaded files go?

Okay, had a big discussion last night with 3 more friends about the nature of the Internet. Since our perceptions were a bit altered, and there where no engineers in the room, this turned into an all-out debate.

Sorry for the misconceptions, but here goes.

When you have, for example, a 2MB file in your computer (without a web connection), that file has a "physical" element right? Somewhere in the hard drive, something is modified because of that file. But, when you connect that machine to the Internet, and you upload that file, where do those 2MB go? I concluded that the Internet was like an infinite and intangible hard-drive on which infinite information could be put. But HOW CAN THAT BE? I simply have no idea what I'm talking about, I'd love for anyone to explain it for me. Like I was 5, of course.

Thanks a bunch!

**EDIT: Great and clear answers guys, I certainly appreciate it!**

[Assistant] Part of why you are having conceptual difficulty here (which others have addressed) is because the internet isn't just a big sea of information: it's a network of other computers. Any data "on the internet" is hosted from a specific computer somewhere.


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

[User] [Star Wars] Can I, average Courascant citizen go up to / in to The Jedi Temple?

[Assistant] I imagine that theres probably a semi-public area you could walk into, sorta like a main lobby, but getting deeper into the temple would probably be frowned upon unless you were there on official business and/or being escorted by a Jedi. Anyone trying to sneak their way in would curiously find themselves walking right back *out* of the temple in a daze, not quite sure what just happened but suddenly filled with a sense to go home, rethink their life, maybe stop selling death sticks on the side...


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

[User]
Can you build Nuclear Weapons from a light-water reactor?

I was reading a wiki the other day where the United States came to a compromise with North Korea (over a decade ago) regarding nuclear energy. North Korea wanted to pursue it for "energy" purposes, so instead, the United States offered to build a light-water reactor there instead.

I would assume there would be little to no supervision outside of the occasional UN visit.

Could you build nuclear weapons from LWR?

Is there a viable reactor we could build in countries that is a good source of energy, you can't build powerful weapons from, and don't need supervision?

I am creating a (fictional) policy on how to attack climate change from the perspective of the U.S.

[Assistant]
Anytime you have a process that involves neutrons, you have the capability to create plutonium. This includes light water reactors.

That said, you need to be constantly removing fuel and separating the Plutonium, which requires complex reprocessing centers. You also need enrichment centers to bring the enrichment rate up from <1% to >95% that weapons typically use.

The best way to prevent a nation from making weapons, is to prevent them from having reprocessing and/or enrichment technology.


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

[User]
CMV: There IS war in Ba Sing Se

I'm a humble cabbage merchant, been travelling the Earth Kingdom for a while now, and everywhere I go I've seen the effects of a war. Raging for 100 years, tearing apart the world. The Earth Kingdom is partially occupied by the fire nation for Rava's sake! And yet here in Ba Sing Se I've been told there is no war?

It just seems to defy explanation, my cabbages have been destroyed daily for MONTHS because of this bloody war. How can anyone try and say there is no war?

Regardless, I don't want to get on the wrong side of the Dai Li, so I'm really looking for any meaningful way in which to convince me that there is no war in Ba Sing Se.

Change My View.

[Assistant]
Ba Sing Se stood here for hundreds of years. Be assured that any conflicts other, less developed nations call war do not match the power of the technologically advanced people of the Earth nation.

Our military is much more powerful than any other army combined. We have the most capable ground troops, able to destroy any war machine of the fire nation. Any ground soldier able to bend the Earth is a force to reckon with all by themselves.

Speaking of Benders. We are in possesion of the strongest element. Strongest at least in the context of war. Ground is everywhere and it is both absolute defense, and unstoppable offense when going against Fire. We have also the most mobility, and we are not limited by our element not being around. Be assured that any offense against our glorious nation would be broken in half in the first wave.

We have the most territories, our cities are surrounded by walls. We have the most people capable of bending the earth. And we are as technologically advanced, if not more than the fire nation. Even without the bending advantage.

Pche, war. Call the scuffle outside our walls a war if you must. Call the bickering of the baby nation a conflict even. Our city was apparently under siege multiple times now, and barely anybody knows about it. You know why? Because this doesnt even warrant an attention of the regular citizens. So dont worry, there is no war in Ba Sing Se. Not only that, but our economy is booming right now, you might be interested in the option of free housing just to sponsor your cabbage trade.


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

[User] ELI5:Why can i lie still in my bed and not break a sweat, but take a short nap and wake up soaked wet?

[Assistant]
When you sleep your body is very busy. It uses this time to grow, repair tissues, maintaining your bodies internal environment (homeostasis)

However night sweats can also be a symptom of infections, autoimmune conditions and cancer.


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

[User]
ELI5: Why does any food that's really healthy taste like cardboard and anything evil like gravy or bacon taste like heaven?

Isn't your body supposed to tell you "this is bad, so here's a bad taste in your mouth" or "here's some delicious healthy steamed bruxel sprouts, here's a taste bud explosion!"??

[Assistant] Because stuff like bacon and gravy have extremely high caloric value in comparison to fruits and veggies. Back in our hunter/forager days, getting enough calories to not starve to death was far more important than having a balanced diet to promote optimum health, so we evolved to go nuts for those things whenever we got the chance.


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

[User]
ELI5: Why is it so important for museums today to have participatory museums exhibitions? Why have the tenet of visitor co-creation become so pervasive?

Some of it can be attributed to funding of course, the museums get money according to how many visitors they have and as the museums can be viewed as an alternative to amusement parks they try to become more like to other attractions to boost numbers. But as museums can enhance the number of visitors by other means than making the visitors participate (in some form or other) and have the same experiences at other places, why is it that to so any museums participatory design seems as the only viable strategy right now?

[Assistant] Because if a museum is just a place you go to look at things and read descriptions most museums don't offer much over wikipedia. Museums are trying to differentiate themselves by being the place you go to actually *interact with* the concepts they're dedicated to, not just to learn about them as you can just about anywhere on Earth with an internet connection.


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

[User]
ELI5: FAQ Why are rapidly falling or rising exchange rates is a good or bad thing for a countries economy or the global economy?

Lately we've been getting questions about why a countries rapidly declining or rising currency rate is a good or bad thing for both that nation or the global economy.

What does a strong or weak currency imply about the nation's current or future economy?

How can a nation artificially raise or devalue their currency? What is the short-term and long-term impact of that?

ELI5-Mods: Please keep the answers generic as possible, and not specific to any current events.

[Assistant]
Let's say you are USA and you sell Hot Cheetos for 1$ a bag. France sells Chaude Cheetos for 1 a bag. It has a different name but basically it's the same bag. Same quantity and everything. If our currency was the same, you'd exchange 1 for 1 and get a bag. But! It isn't. You go to Europe and give them a dollar and they give you .90 Euros. So the same exact bag would cost an American 1.11$. So what France will do is say, ACHETER TOUS LES HOT CHEETOS! And instead of buying 10,000 Chaude Cheetos for 1 each, they will exchange that same 10,000 for Dollars, and get 11,050 bags of Hot Cheetos. France spends the same amount of money, but in the US, they get more bang for their buck and would rather bring in Hot Cheetos than buy their domestic Chaude Cheetos.

Whoever has the stronger currency will then buy from other countries and that's how imports and exports are encouraged. If everyone's money was worth the same, then there would be no incentive to buy things from other countries. And if this didn't happen, you would not have a globalized economy that wouldn't benefit from bringing in cheap goods from other countries, as well as getting money from other countries who buy your products.


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

[User] Why do we only sneeze when awake?

[Assistant]
During REM (Rapid Eye Movement) Cycles, the release of neurotransmitters such norepinephrine, and serotonin are prevented. This causes the body to completely "shut down" during the REM cycles.

The lack of these neurotransmitters prevents the motor neurons from being activated and body's muscles are unable to move. This state is referred to as REM atonia.


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

[User] [Phineas and Ferb] Why is Linda so cavalier about her daughter's apparent delusions?

[Assistant] I think she believes Candice is exaggerating for attention. Linda likely expects Candice to feel like the kids "never get in trouble" while she is "expected to do everything and have no life" -- stereotypical teenage drama. Plus, Linda was pretty "creative" in her younger days, and likely feels like she'd be the same way. There might be a little bit of Linda thinking that Candice is still dealing with having a step family.


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

[User] What is physically happening in the brain when we forget something?

[Assistant]
Many times it is the result of either inefficient encoding, or an insufficiently salient cue for retrieval. Memory traces do degrade with time, but sometimes a memory can be retrieved by using a different cue.

Also, while long-term potentiation seems to be necessary for memory, there is not consensus yet on whether it is sufficient - there seems to be more to memory than strengthening or forming new synapses. Our lab tends to think about memory as a pattern of activity within a network of neurons which would depend on LTP but is another level of abstraction higher.  So forgetting  may be the result of changes within the network, as organization at the cellular is a bit chaotic and probabilistic in nature, or in changes with the input into the system could render the information in the network inaccessible i.e. the information could degrade, or simply become less accessible, or both.

Source: PhD student in cognitive neuroscience, studying memory.


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

[User]
[SW] The Empire is a good place to live for decent law abiding citizens like me. Its only the aliens who cause problems. Why can't anyone understand that?

The new Death Star project has created tens of millions of new jobs and bolstered the sagging economies of many worlds.

[Assistant]
The first thing you see in a new hope is the empire boarding a diplomatic vessel through a brutal breach assault followed by Vader choking bitches and snapping necks based on a hunch that they might be smuggling blue prints.

The empire is a good place to live provided you don't complain about the brutality, the inequality, the death squads, the summary executions and that's easy because they're not doing it to you.

Until one day they show up for you and everybody else is looking the other way.


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

[User]
Does an eye "absorb" a proton?

So I am looking at the sky, at all the ancient stars.  And the photons from those stars may have travelled for thousands of light years to get to me.  When the photon strikes my retina, and alters (I think) the molecules, is the photon converted to energy and is now more or less a part of "me"?.  Every time I look at the night sky, am I taking on a little more of the heavens, no matter how slight?

*edit: typos*

*edit: I know I typed proton in the title, I derped, I meant photon*

[Assistant]
Yes, this is an accurate description of the absorption of photons by the retina.

They've traveled a very long distance for a very long time (in your frame of reference) to reach you.  Once they hit one of the rods or cones of your eye, they convert to a chemical form of energy which is transmitted to the brain.

Note: Your title has a small typo.  Photons and protons are distinct.


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

[User] ELI5: After invitro eggs are fertilized, are they kept at a certain temperature to grow before implanted? How does the lab part work?

[Assistant] They are incubated under optimal conditions (the correct Temperature, Oxygen levels and nutrients) , usually until a blastula is formed. at this point a cell can be removed for genetic analysis (also called  Preimplantation Genetic Diagnosis  or PGD) and the embryos can be frozen in liquid nitrogen until needed.


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

[User]
[Battlestar Galactica (2003)] Why didn't the humans stay at Ragnar Anchorage?

Not only was the Ragnar Anchorage a munitions depot, but the hydrocarbons used in the Humans' weapons are also harvested from Ragnar's atmosphere. Although we don't see them, the tools used to make the munitions are almost certainly right there. They may not be trained in the exact sciences of how to use those tools, but I think that there are many examples (the relative ease with which they got the water off Kimiko for instance) that prove that the engineers of the Galactica, along with whatever aid they might get from other remaining scientists and engineers, are capable of some pretty awesome feats of engineering. I think it is safe to assume that they would be more than capable of operating whatever machines were at the Anchorage.

In addition, Ragnar is well known to produce a specific type of radiation that is very harmful to Cylons. It's by no means an instant kill but it was enough of a deterrent for the Cylons to choose to station their fleet outside and wait, rather than go in. The fact that the Cylon called Leoben still tried to kill Adama while suffering from the effects of the radiation is not necessarily proof that the radiation's effects are weak either. In fact it is the opposite; the Leoben model (also known as Number Two), is known to be capable of a superhuman strength that surpasses that of the other humanoid Cylons. If he had been at full strength he almost certainly would have killed Adama. This suggests that the effects of the radiation actually may be fairly powerful, especially on weaker models.

I admit the odds of winning the war against the Cylons aren't great, but if you wanted a place to wage a war from I think this would be it.

**TL;DR:** The Ragnar Anchorage produced munitions and had Cylon-sickening radiation, why didn't the humans stay there?

[Assistant] I think Ragnar wouldn't be safe for very long.  The Cylons could decide to send in ships despite the radiation, or just bombard it from long range.  Shortly after the rag tag fleet escaped, Cylons boarded the station anyway, so it couldn't have been that safe.  The real question is why didn't the Cylons go in sooner?


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

[User]
How would the Chernobyl disaster have appeared to observers at a range of galactic and intergalactic distances?

Im assuming it would not have been detectable at intergalactic, or even medial galactic distances. But if we had had a radio telescope pointed at a similar event on a planet orbiting Alpha Centauri, could we conceivably have caught it? What we we have observed?

[Assistant]
Not even close. The amount of energy in the blast wasn't nearly as big as intentionally designed atomic bombs. Those range from kilotons to megatons of TNT equivalent. The Chernobyl blast was probably <20 *tons* of TNT equivalent - so like a fraction of a percent of an atomic bomb. The bigger problem was that it produced a cloud of radioactive steam that spread out across Europe, and that it sprayed the nearby area with radioactive material.

This explosion produced about as much energy as we get from the Sun every few milliseconds. The Earth's reflected light from the Sun would be a much stronger signal than a nuclear explosion. But even that would be difficult to observe from Alpha Centauri, because the Sun is so much brighter than Earth that it totally outshines us.


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

[User]
If the universe is only 13.7 billion years old and 1 light year is how long light travels in a year, how have we seen objects farther then 13.7 billion light years away?

I have heard that the entire observable universe is 90 billion light years across. How do we know this if objects in the universe only had 13.7 billion years to send light to us?

[Assistant]
The key here is that the universe is expanding.  When we say "how far away" we're seeing objects, we mean "how far away are they now", not "how far away were they when they emitted the light we're seeing now".

The light we're receiving that was emitted from something 13.7 billion years ago is just reaching us now... but in the meantime the universe has expanded to put that something much further away.

This is not so different than throwing a ball to a person who is running down a field.  But now imagine the field is expanding... and the ball-catcher says "man, that dude threw the ball 4000 meters!"...when they were only 40 meters away when you released the ball.


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

[User]
[Pacific Rim] What is the world government thinking in disabling the Jaeger army?

Why does the world government opt to just disband the Jaeger army and simply put up a stupid wall? They know that the Kaiju are getting bigger every time they come through and yet they think they can just put up walls to ignore the problems. I know that the price of making Jaegers is extremely high, but how is pretending the problem doesn't exist solve anything. I am basically asking why the world government seems to make really stupid decisions. Also, as soon as the wall broke why didn't they immediately reinstate the Jaeger program? And why did they think the wall would even work in the first place?

[Assistant]
It's thinking that they don't have the capacity to replace Jaegers as the attacks increase, and until one broke through no one realized that the Wall could be broken that fast--the plan for the wall was for it stall Kaiju for days while defense turrets spaced along the length of wall turned the thing into swiss cheese.

It's not that they looked at the books and said "oh, well making a bunch of robots is stupidly expensive. Guess we should just go *build a massive wall of concrete around the Pacific Ocean*." The issue was not cost, it was that even with the massive manufacturing capacity of the Pacific Rim Nations, 'bots simply couldn't be made as fast as they were knocked down.


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

[User] ELI5:Why do women usually live longer then men?

[Assistant]
It mostly comes down to work.

The life expectancy for males is slightly lower than women because dangerous jobs are usually done by men, and men generally work longer than women. Soldiers, lumberjacks, miners,  are pretty much only done by males and so will bring the average life expectancy down. Males are more likely to smoke than women, causing more men to die early due to problems cause by smoking, bringing the average down.

> Men take more risks.
Men are more likely to work in more dangerous jobs.
The way men put on weight, etc is more likely to lead to cardiovascular disease at an earlier age.
Men are more likely to not seek medical attention for injuries and disease.
Men are more likely to be the victims of violent crime (wars ect).

Sidenote: this is also why males on average get paid more than women. It's not because of unequal rights, but the fact that men *work more* than women on average. (More manual labour/more dangerous work environments/longer hours).


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

[User] ELI5:What does it mean when hawks and eagles have better eyesight than us? Does it mean they can literally zoom in on creatures on the ground, or do they just see things in a higher resolution?

[Assistant] They can see more detail- they have the equivalent of 20/2 vision, they can see clearly at 20 feet away what a normal human needs to  be at 2 feet away to see clearly. They also see a broader spectrum of light than humans, so they can see more colors than we can.


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

[User] [MCU/DC] What is considered and Avengers Level threat? Does the Justice League have anything similar to that?

[Assistant] Depends, on the universe. Sometimes the heroes only gather together to defeat a threat that could destroy the earth (Ultron, Thanos, Darkseid, Starro, etc.) Other times they stay together and go on daily missions against threats that would only harm a city, state, or small country sized area. In some worlds they even regularly help during search & rescue, evacuation, and reconstruction efforts for natural disasters like hurricanes and volcanic eruptions.


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

[User]
I feel like the world doesn't take overweight people seriously... CMV?

Sure, there are plenty of successful people who are overweight, but their weight is 90% of the time something that people will bring up. A good example is Melissa McCarthy. Everyone loves her and thinks she's great, but she will forever be cast as the "funny fat girl", same with Rebel Wilson. If they were to lose weight, they could be taken more seriously in Hollywood. Governor Chris Christie, regardless of what decisions he's making for the state of New Jersey, people are constantly reporting about his being overweight. If he was average-sized, people would focus on what he's doing as governor. I don't know, I'm overweight myself and I feel like I'll never be taken seriously in the work force or on the dating scene. Change my view, please.

[Assistant] People see weight as something that all people can change through work, and thus (sometimes wrongly, sometimes not) associate it with laziness and "slackers". Thus, a successful person like Bill Gates could never be overweight no sir that mother fucker has to work hard saving the world. But Chris Christie? Why i bet he just sits in his big soft governors chair all day and aint never had an honest day out on the campaign trail with us plebs.


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

[User] ELI5: What is the Universe expanding into?

[Assistant] As a physics Nobel laureate put it on Dr Karl's show a few months back, what you have to remeber here is that it's not space that is expanding, but rather spacetime.  As he said, you could regard it as expanding into the future...


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

[User]
ELI5: Why does slurping a hot beverage make it feel less hot when drinking it?

I'm drinking tea right now and it's piping hot to drink normally but when I slurp it (yes that noise) I'm talking in the same amount I would be drinking normally but it's a lot easier to drink. What's going on?

[Assistant] You're also using your mouth like a carburetor of sorts. Adjusting the ratio of air rushing past the surface of the liquid also changes the temperature of it while providing cooling to the tongue and inner surface of the mouth.


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

[User]
Why cant electric vehicles use total regen braking?

Here is my example. A Tesla has two regen settings and you can do one pedal driving to a point. My question relates to the need for physical disc brakes and whether theyre really needed. What is it that prevents using the motor as the brake? Is it legalities at this point? Does this generate too much electricity too fast for the battery to ingest? Is it the wiring?

Ive heard that an electric drive motor could easily lock up the tires of a car at high speed so I dont think it is the motor.

[Assistant]
Regen braking force bumps into a few limits. The maximum rate the battery can charge, the maximum power the conversion electronics can handle, and the thermal limits of everything involved.

But the power limit is the most obvious. When the battery is full, theres nowhere to send power from regen, so it just doesnt work.  Drive a few miles and theres room, but you cant charge a very full li-ion battery very fast so you have regen but its very weak. Same issue when the battery is cold.

But even when things are ideal, and the battery is at the perfect temp for maximum charge rate and low state of charge, it can only handle about 250kW, or 335hp. (Used Tesla as an example here) That is much lower than the power of friction brakes. A cars brakes are generally many times more powerful than its engine.

And with a future battery that could handle the needed charge rate for emergency stops, youd still have the problem of not being able to stop when the battery is full.

Edit: this is also why small-battery hybrids have very weak regen braking force, while big-battery EVs can produce regen braking force more like medium braking the larger battery allows more charge power, which means more stopping force before you bump the limit.


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

[User]
[Star Trek] After Kirk's visits, how come we never see or hear anything about the highly-improbable gangster, Roman, or parallel American/Russian culture planets?

You'd think that such planets would have huge sociological interest for the galaxy, and yet they seem to completely disappear from the historical records.

[Assistant] The records you're referring to really only focus on the 5 year mission for the first USS Enterprise.  The Enterprise (and largely the whole Constitution class) was and exploration ship, not a science ship, and thus it lacked the specialized crew and equipment needed for long-term study.  It's likely the Federation dispatched a more specialized ship and crew to study these sorts of planets.


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

[User] ELI5: Why cant the ring finger extend independently of its adjacent digits?

[Assistant]
The ring finger and middle finger each have two tendons that connect near the base of the fingers. One of the tendons from the ring finger goes underneath a tendon for the middle finger, while both middle finger tendons are on top. You can lift just your middle finger because nothing is in the way, but when you try to lift just your ring finger one of the tendons is blocked/held down by one of the middle finger tendons.

It can go up a little but it's already under tension and tendons can't stretch very easily, so the ring finger doesn't go very high.


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

[User]
ELI5 - Why are Muslims OK with naming their children Mohammed, but not with depictions of Mohammed?

Why is one OK but not the other?

[Assistant]
Depictions of Mohammed or any religious figure borders on having a "graven image" or what we would designate as an idol. That is why Islamic art is primarily geometric designs. This is also something that many Protestant branches of Christianity also believe and why they do not have pictures of Jesus, Apostles, Mary, etc and why they have issue with Catholics.

Naming someone after the prophet is not worshiping that child, it is just honoring an important person.


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

[User]
CMV: self defense should be allowed in schools

~~Self defense is one of the most important things that you can know. If you end up in a fight, knowing how to fight back can save your life in some cases.~~

~~So why do we get in trouble when we try to stand up to our bullies? This only benefits the bully himself, because now it takes more balls than it should to get out of the relationship.~~

~~Most schools have a policy that whenever you are bullied, you should report it to a teacher. However, not only is that not a real option in the real world, it often doesn't work. Unhelpful teachers and counselors will do *nothing* to resolve the problem, making the bully even more powerful.~~

~~Lastly, as I mentioned in the beginning of the post, self defense is very important to know. We should take time to teach proper and effective technique when doing it, so everyone is better prepared. Sweeping it under the rug is not going to get rid of fighting; it will only continue the current trend that we all are getting wimpier.~~

CMV!

**Edit:** I admit to a reversal on my own opinion. I cannot defend it anymore.

But I do have a new opinion. Schools should have security cameras in the hallways, and if bullying is watched/reported, the administration **must** deal with it/investigate it.

[Assistant]
So, are you saying they should explicitly *allow* self defense or just not prohibit it? Because either way, that's a GIGANTIC liability for the school. Kids fight and get hurt all the time. Encouraging it is opening themselves up for countless lawsuits.

To start, what level of bullying warrants self defense? Verbal abuse? Shoving someone on the playground? Also, how much self defense are you permitted to use? What happens when Billy punches Timmy in the mouth and knocks out his tooth? Or breaks his arm?

There are several videos on youtube of kids fighting back against bullies who seem to deserve it. The real world is much less clear. Because there's no chance of applying a fair metric to this, there's no way a school could condone or approve of fighting in self defense without making problems way worse. (A better solution would be for the kids' parents to teach him to fight back and say that it doesn't matter if they get detention.)


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

[User]
Why Pitch Up to Go Up while Flying?

I was ruminating over the physics of flying, and I arrived at the question: why would you want to pitch the aircraft up in order to increase vertical speed? I know lift is based on both airspeed and on angle of attack, but doesn't increased speed produce a higher increase in lift than does an increased angle of attack?

Let's say that a plane is accelerating down a runway. The angle of attack is 0, and the speed is increasing. At some point you want to pitch up ("rotate") to lift off, but wouldn't that reduce the vertical component of the lift vector? So then where does the extra vertical acceleration come from? The thrust vector, which is now pointing slightly up?

Thanks!

[Assistant]
In introductory flight training (I only have a few hours, so pilots feel free to correct me) you actually are taught to control altitude/rate of climb largely by using airspeed. Increase throttle to go up, decrease throttle to go down.

>At some point you want to pitch up ("rotate") to lift off, but wouldn't that reduce the vertical component of the lift vector? So then where does the extra vertical acceleration come from? The thrust vector, which is now pointing slightly up?

The lift vector and thrust vector do change a bit, but it's comparatively minor - typically less than 10 degrees on takeoff rotation. The effect of changing the angle of attack on lift production is a much larger factor.

>Let's say that a plane is accelerating down a runway. The angle of attack is 0

Actually that's not exactly true, depending on where you define a 0 angle of attack. Next time you're at an airport look at the orientation of the wing root of an airliner on the ground. With a level fuselage the wing root is mounted around +3 degrees.


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

[User]
Why do most of us stick out our tongues in some fashion when we're concentrated on doing something?

Edit: Yes, I do mean most of us.

It's also interesting to note that we all have different variations of sticking out our tongue. Some of us move them around, while others chew on them or simply stick them out. Additionally, I found that some things I would expect to trigger this for me don't, while others do. I am completely straight faced when I play guitar, but when I start coloring, I look like a little kid again.

[Assistant] Sticking your tongue out or biting your lip while concentrating is not really that weird.  Michael Jordan was famous for his tongue sticking out while going up for a dunk. It is an example of whats called motor overflow or motor disinhibition. It happens sometimes when our brains are working really hard at something.  Normally, the brain keeps the brakes on the parts of the body it doesnt want to move. However, when we concentrate really hard on a tough task, sometimes the brain lifts the brakes on other parts of the body (most often the face, lips, tongue, etc.) making them move without our control. As we get older our brains get better at controlling the brakes (inhibition) and the motor overflow goes away most of the time, but some people still have this happen when they are grown ups. There are studies that show it is more common in people with ADHD.


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

[User]
ELI5: What are the differences between consumer-grade CPUs made by AMD/Intel and Digital Signal Processirs made for industrial/military purposes?

Corollary: What makes the semi conductor material so important?

[Assistant]
You seem to be confusing two things:

- general purpose CPU vs DSP.  DSP are CPU whose instruction sets and internal architecture are particularly well adapted to signal processing.  For such kind of application, they are more powerful (per watt, per dollar) than usual CPU.  You probably have several in your home (your cell phone, your modem, ...)

- ICs (general purpose CPU, DSP, memories, ...) are usually designed to work in a certain temperature range (and with less radiation than a threshold).  You can design them and chose the fabrication process to make them usable in a wider range of temperature and with an higher level of radiation.  This has usually a cost in performance but is needed for some industrial and military applications.


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

[User]
ELI5: why is defragging not really a thing anymore?

I was born in 1973, got my first computer in 1994, defragging was part of regular maintenance. I can't remember the last time I defragged anything, even though I have several devices with hard drives, including a Windows laptop. Has storage technology changed so much that defragging isn't necessary anymore? Is it even possible to defrag a smart phone hard drive?

edit to add: I apologize for posting this same question several times, I was getting an error message every time I hit "post"... but from looking around, it seems I'm not the only one having this problem today.

[Assistant]
* Bigger disks
* Better filesystems
* SSD vs. HDD
* Larger caches

Bigger disks: Most folks don't spend much time with their disk at 90% capacity anymore, so the filesystem doesn't have to split files up as much to find room for them.

Better filesystems: The OS engineers have come up with cleverer ways to organize files on disk, which produce less fragmentation even under storage pressure.

SSD vs. HDD: The geometry of storage devices is different, and SSDs are also just plain faster.

Larger caches: Your machine has lots of RAM, and your OS can use a lot of it to prefetch and cache disk contents, so you don't notice the effects of slightly slower disk access due to fragmentation.


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

[User]
ELI5: How do we know Dinosaurs weren't purple with yellow polka dots?

Is there any science behind the colors of Dinosaurs, or is it simply speculations?

[Assistant]
Pigments have been found in some fossilised dinosaur feathers,  so we know the colour of a couple of birdlike dinosaurs.

The rest is speculation,  based on the reasoning "if lizards are green and brown now, then they probably were then".


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

[User]
[Jurassic World] Why was the original visitor centre abandoned?

In the original movie we see that the visitors centre has the control room, the labs, a commercial kitchen and the gift shop, indicating that the rest of the tourist facilities are there. Its everything you need to run the park and accomodate guests. And as the centre of guest services it stands to reason that its prime real estate.

Yet in Jurassic World and Camp Cretaceous its an abandoned ruin. Overgrown and forgotten. The whole island is mapped and heavily rebuilt, but its somehow hidden. Darius, whos studied Jurassic World and dinosaurs doesnt know its there.

A lot of it would have been hurt by the years of abandonment, but the fact that Zack and Grey are able to get the Jeeps working shows that it hasnt even been looted. Even if nothing inside is worth salvaging (again the jeeps working indicates otherwise) the building itself would be a great shortcut in the expansion of the park.

So why, and how, is it forgotten?

[Assistant]
Because if you use that one, people might find out about the time your company killed a load of people with rogue dinosaurs , and that might make people not want to come to your dinosaur park.

It's not *forgotten*. It's *covered up*. If there is a place where your company committed, at best, homicidal negligence? You make sure as few people as possible ever learn about it and get the chances to put the pieces together. You definitely don't make it into a theme park.


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

[User]
How is dissolved oxygen related to the oxygen in the chemical formula H2O?

Im kinda confused about what dissolved oxygen is a measurement of-- if H2O is ~89% oxygen by mass, is "water" with 0% dissolved oxygen in it just hydrogen? If not, what does it mean for oxygen to be dissolved "in" a substance that is primarily made of oxygen?

[Assistant]
You're mixing up two different things, but that's okay, I'll try to explain it: There is waterthe moleculewhich has two hydrogen *atoms* and one oxygen *atom* bound together and oxygenthe moleculewhich is two oxygen *atoms* bound together. When oxygen is dissolved in water, it means that among all the water molecules there are some oxygen molecules swimming about with them.

Consider O's being water and X's oxygen molecules:

> OOOOOOOOOOO

> OOOOOOOOOOO

> OOOOOOOOOOO

This is pure water, but remember each molecule still has a single oxygen atom and two hydrogen atoms. Now let's add some dissolved oxygen.

> OOOOOOO**X**OOO

> OOOO**X**OOOOOO

> OOOOOOOO**X**OO

Now mixed among our water molecules are some oxygen molecules. Sure, the majority of the mass is still just oxygen, but oxygen molecules and water molecules are very different. You just have to remember that some atoms are usually referred to by their molecular name. Hydrogen has the same naming convention where the hydrogen molecule is two bound hydrogen atoms. The reason this confusing convention exists is that chemists didn't always know that things like hydrogen and oxygen were naturally two atom systems on Earth.


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

[User]
ELI5: Why some drinks, especially vitamin drinks, say "drink it cold" on the packing?

English ain't my mother language, so the title might be a little off, but I'm sure you'll get it.

[Assistant]
Food and drinks taste very different at different temperatures. Most people prefer to drink coffee hot, it's not nearly the same when it's warm or cool or cold. And beers are meant to be served room temperature, cool, or cold depending on their type because their flavour changes at different temperatures.

The drinks you refer to are designed to be served cold because that's the flavour that the manufacturers think is "best" for them.


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

[User] ELI5: Why don't we just dump our garbage into a magma pit?

[Assistant]
For starters, there aren't many magma pits in the world. It's a lot easier to dump your garbage in a place no one cares about that's maybe 50 miles away, as opposed to one 2000 miles away. Most of those pits are also small, and would be overfilled quickly. We throw out a lot of trash.

Secondly, many products create hazardous or toxic chemicals when burned. When we burn trash using an incinerator, the trash needs to be separated so that hazardous products are not burned.


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

[User] [ELI5] How is it that our brains can know a certain word we want to say, but for some reason can't think of it until someone says it outloud?

[Assistant]
Even though we register that we are having an internal monologue for our whole lives, we often actually think in concepts instead of real time sentences (besides forcing yourself to consciously think in sentences).
This is also how our hours long dream sequences can in reality be only 4 minutes long.
When we want to say something but can't remember the word, we are feeling the concept of what the word is without remembering it's title.


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

[User] [Star Wars] What is the purpose of Storm Trooper armor if it can't even stop pistol fire?

[Assistant]
Well one, any protection is better than no protection.

Two, it protects against some environmental hazards and extreme temperatures, and limited exposure to the vacuum of space.

And three, its threatening appearance is meant to inspire fear against enemies of the Empire.


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

[User]
[ELI5] What does "x" mean at the end of a sentence?

I've seen  British people, well, people from the UK, type "xx" or just "x" at the end of sentences, why? Is that like them kissing the receiver of the message?

[Assistant] It's come from the days of hand written letters, when one person would physically kiss the paper, and draw a cross to show where they did this. When the other person got the letter, they could physically kiss the cross, and they would have had a long distance kiss!


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

[User]
Is it better to take a W or abandon all hope of graduating summa cum laude?

(US) I'm in my senior year and I plan to move on to graduate school. During a recent discussion of my grade on an early project, the instructor told me outright that students in her class rarely gets As, so I'm tempted to withdraw if the stakes are high enough.

It's an elective class that I could easily replace in the spring term. Does it look better on my grad school applications if I don't have a withdrawal on my record, or that I graduated with highest honors? I currently have a 4.0 GPA and my discipline requires it for the honors degree.

[Assistant]
IMO, the withdrawal looks worse.

Honors really don't mean a lot in the scheme of graduate admissions, and I'd worry that you withdrew from a course to protect your GPA.

The people I've seen have the most trouble in grad school are the ones who are too protective of their GPA, hence the W would look worse to me than the (very slightly) lower GPA.


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

[User] ELI5: Why is Japan not allowed to have an army?

[Assistant] They're not allowed to have an offensive military force.  They do have defensive military forces.  The reason is because of their history of military aggression, particularly in World War II, and their defeat in that war.


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

[User] ELI5: How do we get perfectly lighted pictures of a planet that's so far away from the sun?

[Assistant]
Anyone who is answering "there's plenty of light" is full of shit. Pluto is very dark and it's not easy at all to take photos of Pluto that look that good.

Have you ever tried taking a picture with a film camera where you can manually set the exposure time?

On a bright day, you can open the shutter for 1/60 of a second (or less) and get a nice clear picture. Indoors, you need to open the shutter for longer, because there's less light.

Pluto is really dark, so the New Horizon spacecraft has to open its camera shutter for a long time in order to get such a bright, clear picture.

In fact, it needs to open it so long that the planet moves in that time, so it has to *rotate* the spacecraft to keep the planet centered!

Not easy.


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

[User]
Can something have negative mass?

Also when light is getting sucked into a black hole does that mean it is going faster than light? Doesn't it have to be going in the opposite direction faster so it goes in?

[Assistant]
This is an open question.  No examples of negative mass are known, but since negative and positive masses are gravitationally repelled, we wouldn't expect to find any near stars and planets.

There are a bunch of interesting theoretical computations of its properties (and a novel by Robert Forward, *Timemaster*), but the consensus is "probably not."

> Also when light is getting sucked into a black hole does that mean it is going faster than light?

No.  Understanding black holes properly requires understanding general relativity, sorry.  Very briefly, the fact that escape velocity is faster than light doesn't mean that a non-escaping particle must be moving faster than light at that point,  More generally, your familiar mental models of Newtonian physics and the way velocities add don't work properly near the speed of light.


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

[User]
ELI5: what's the difference between controlling the volume on the PC and controlling the volume on its speakers?

Is there a difference if I have the volume set at 1 on the audio source (PC) and at 100 on the audio output device (in this case, the speakers), and vice versa?

[Assistant]
The difference is the signal to noise ratio you end up with.  Keeping the PC volume low and then cranking up the speaker is like recording someone speaking softly outside and then amplifying it: all the background noise gets amplified too.  Keeping the PC volume high and turning down the speaker is like recording someone speaking loudly, and playing it back quieter: their voice was loud compared to the background, so it sounds better.

You can't straight up max out the PC output because it's designed to be able to power headphones and small speakers on its own, so it can be turned up "too high" and cause distortion.  You want to turn it up as high as you can without getting distortion on loud sounds, and then adjust your speakers to taste.

This sort of volume control is really important in areas like... oh, electric guitars, where the sound is overdriven, and distortion is often desired.  Loud amp, quiet guitar vs loud guitar, quiet amp makes very different sounds.


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

[User]
Allowed electron orbits seem odd and purely a mathematical construction. Are they just theory but reality gives more laxitude to where an electron might be?

In A Brief History of Time, Hawkins explains the allowed orbits by saying only integer multiples of an electron's wavelength are allowed, otherwise after a certain number of orbits the electron's wave will destructivley interfere and the e- will disappear and you restrict your solution-space to discrete allowed orbits.

Does this mean we limit ourselves further to electron energies that have wavelengths longer than or equal to their orbital circumference so they can intefere? If the wavelength is shorter than the circumference would we not have a band of orbits which will never destructivley interfere and hence not limit ourselves to the simpler situation of discrete energy levels for the e-?

Also, as a mathematician, if space around the e- is compact these allowed orbits (to me) represent the limit points of allowed orbits and that in the real world you would have a band of 'effectively' allowed orbits which would be stable for long periods of time without ever collapsing into the nucleus or flying out into space.

The band might be small, but a band of any size at all would give an uncountabley infinite number of possible orbits in the physical world, hence when you come to describe the e- in the world of quantum mechanics you can't use the simplification of discrete energy levels which will messes up their representation when expressed as vectors.

[Assistant]
If you're a mathematician, I'd recommend reading more rigorous sources than A Brief History of Time.

Electron orbitals are the stationary solutions of the time-independent Schrodinger equation.

The electron having negative total energy (where "zero" energy is defined by a particle at r = infinity, with zero kinetic energy) imposes boundary conditions which lead to a discrete spectrum of bound states.

The modulus-squared of the stationary solutions gives the probability density for where you'd find the electron in space if you measured its position.


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

[User]
[MCU] If someone used the Infinity Gauntlet out of spite to force Thanos to mentally realize all the flaws in his plan and that all the pain hes caused has helped absolutely no one, would he mind be able to handle that truth, or would it collapse on itself?

Lets say this is after he sacrificed Gamora as well.

[Assistant]
I mean if you used the IG to force Thanos to realise, then yes, because you'd be brainwashing him so he'd take on that line of reasoning.

But if you just sorta secured him, didn't brainwash him beyond making him willing to listen, and then used the IG as an overpowered presentation tool while you went through your PowerPoint of "Why Thanos is Wrong" *thoroughly* with evidence, testimonies, debate sections, simulations and scientific evidence from numerous sources, you may be able to convince him. At that point he'd regret his actions and Gamora's death to the extent of having an emotional breakdown. But that's seriously asking a lot to get to that point. You really have to secure Thanos for a long time and bring the best possible presentation (potentially with Reality Stone illusions too) to stand a chance.


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

[User]
What happens to a metal baseball bat when "it dies".

In most non-pro leagues expensive, metal baseball bats are used that typically last for 1-2 years (less if used by a whole team) before they are considered "dead." This means the bat no longer seems to have the pop as the ball comes off the barrel and typically results in the baseball flying slower and shorter and becoming easier to play.

So what changes inside the baseball bat from when it is brand new to when it is considered "dead"?

[Assistant] High-cycle metal fatigue. Collisions between a new bat and the ball are mostly elastic and lose little energy, transferring most of the kinetic energy of the bat into the ball. Over repeated collisions, the metal fatigues and the collisions become increasingly plastic, losing more and more of the kinetic energy into plastic deformation of the bat. Most aluminum alloys lack a fatigue limit and will eventually fracture even under weak repeated stress.


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

[User] ELI5: What exactly happens when we "zone out?"

[Assistant]
There are quite a few factors to the whole zoning out thing. Boredom, stress, intense focus, or just thinking in your own head.
Also that there are 2 types of zoning out: being aware that you're zoning out and being unaware of it.
But the gist of it is, (paying no matter to what triggered the zone out, as it could be any number of things, and is irrelevant.)
SO, the beginning of a self aware zone out: Your mind snags a piece of information, that stood out to you, or you experience a minor revelation off that that one piece of information.
Then, a number of connections piggy backing the original are now being made. Fairly rapidly too. This is now taking up most, if not all, of your attention, and since you're awake and concentrating on something in your head, not looking at anything, it causes that weird out of focus vision.


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

[User] Do caterpillars need to become butterflies? Could one go it's entire life as a caterpillar without changing?

[Assistant]
Insects go through stages culminating in the final imago, the adult insect that is distinguished by its precursor stages in that only it can reproduce.
So caterpillars can totally live a long, full life of caterpillary wholesomeness, but they cant have descendants until they transform into a butterfly or moth.

Realistically speaking, in most species the vast majority of larvae get eaten by something bigger long before they reach adulthood, and those who make it are the rare exception. So in a way, many caterpillars actually do live their whole life in the larva stage, never growing up... but probably not in the way you imagined.


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

[User] ELI5: Do usbc devices "pull" just the wattage they need from the charger, or does the charger "push" all the power it can?

[Assistant]
The device sets the amount of current drawn, and the power supply determines the volt-amps allowed for the circuit. Cell phone chargers are often found in multiples of 5 watts (volt-amps = watts).

5 volts at 1 Amp is 5W (slow charger).

5 volts at 2 amps is 10W (fast charger).


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

[User]
[WH40K] Are the Imperium and the Eldar really enemies?

Seeing the cutscenes for DoW, DoW2, etc, again, it seems that Imperials and Eldar really like allying with each other at the mere hint of a third force. Why don't they just kiss and make up at this point? What are they fighting over?

[Assistant]
Both races are utterly convinced of their own superiority, but a God will ally with a goldfish if it puts more meat between them and an enemy.

++THOUGHT OF THE DAY: The Alien is clever in its own ignorant way. Be Wary.++


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

[User]
[Cinderella] How comes the shoe only fits one woman?

It's a prince in the story, right? So it's presumably a kingdom they're in (or at least a constitutional monarchy. God Save the Queen) so what about the hundreds of other, probably less Disney-friendly women who have the same shoe size?

[Assistant]
The shoes, dress, her carriage, all these things were created by the fairy godmother especially for Cinderella and so it's not a case of size, but that the shoe is a magical construct that is only for her.

The fairly godmother is trying to help her, so everything she does is to get Cinderella and the Prince together - so the shoe only fits her and it doesn't disappear and then Prince has a symbol to search for her with.


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

[User]
[Endgame] Spoilers, obviously

Why did they need all of the Infinity Stones and not just the Time Stone?

It's been established that the Time Stone can repair other Infinity Stones. So why not just grab that one?

[Assistant]
It's not that the Time Stone can repair other Infinity Stones, but that it can reverse time until the point where the Stone was destroyed. Using the Time Stone to do anything other than reversing the immediate past is incredibly difficult, and pretty much the only person who would know how to do so is Doctor Strange, who had a bad case of being dead.

Rewinding time five years was not a viable option.


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

[User]
[Independence Day] How many people survived the war?

The general talks about "Forces are at 15%" or so.  I was wondering how many people lived through the alien onslaught?

[Assistant]
To be honest... we only see the City Destroyers fire once, at the 36 most 'important' cities on the planet. Even if we calculate based on the largest cities (which we know it can't be, because Washington doesn't even make the top 100) then you're still looking at only about 400 million dead. Or about 5% of the global population.

Which would seem to imply that the majority of losses would have, in fact, come from the absolutely disastrous global counter-attack after the initial strike.


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

[User]
How does temperature-dependent sex determination work? Wouldn't the embryos already contain XY/XX chromosomes?

In some species, such as amniotic reptiles such as the alligator species, temperature plays a key role in determining the sex of the offspring. How does this phenomenon work? Surely the developing animals already have the genetic material needed to decide their sexes?

[Assistant] Not all animals use sex chromosomes. In the species you mention, there are no sex chromosomes. Instead, gene regulation that leads to the final sex determination is controlled by temperature. There are zillions of different ways to determine sex.


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

[User]
Is literary anti-cognitivism a seriously held position among professional philosophers?

I've recently been reading about literary cognitivism and what I've found is that most (actually all) the papers I have been able to find online have been in support of the cognitivist position. I think I'm quite strongly in the anti-cognitivist camp, but because of the above, I'm worried that this view may not be taken seriously.

The impression I get is that anti-cognitivism is sort of like radical skepticism in epistomology. That is, anticognitivism acts more like a foil for people to explore the question of what we can actually learn from literature, rather than a serious position people actually hold. I think the reason I get this impression is that in the articles I've read, it's often taken for granted that the reader will agree that literature *seems* to have some cognitive value, and it's only the task of the article to explain what this cognitive value could plausibly be. I don't have this initial impression of literature's cognitive value, so I don't find this kind of argument particularly convincing (just because they don't seem to be written with people like me in mind).

I understand that my position would probably be quite radical to people who study literature, but I'm quite curious about what philosophers tend to think.

[Assistant] A common reason why someone might find a view that philosophers consider to be common sense to be unintuitive is that the philosophers have something different in mind than you do.  For instance in this case, what kind of cognitive value do you think literature doesn't have but you believe aestheticians believe it to have.


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

[User]
What is the Point of Interrupts if the CPU has to Constantly Check for Interrupts?

From what I understand, the point of interrupts is to allow the CPU to not have to constantly check the status of devices and such. But doesn't it defeat the purpose of interrupts as a whole if it has to check once per every FDE cycle?
Is it just so that the CPU can check for interrupts and figure out from which device they are from after rather than having to check each device individually every cycle?
Is it because for the majority of cycles there are no interrupts to handle?

[Assistant] The CPU doesn't check every device or whatever. At the end of every cycle, it checks if there is any interrupt, which is cheap to check, especially for hardware interrupts that are signified by physical pins. If there is an interrupt, instead of handling the next normal instruction, the CPU jumps to the interrupt service routine which does the heavy lifting.


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

[User] [Fallout] Why has no music been created since the mid 50s?

[Assistant]
Because in Falloutverse World stopped rotating in 50's, at least for USoA. This is the Golden Era, we cannot progress any much further, we stay. Art can't progress more than that.
It's like the old times of, let's say, Baroque or Renaissance where art styles holds for centuries, not for decades, and even if there were styles of '60s or '70s, they didn't hold up.
Also, the 50's are the breaking point, this is the moment where Falloutverse splits from our Universe, it's easier (from technical point of view) for Bethesda to bring up the music from the time when both of them were the same, than creating music from age that comes after.

But TL;DR - it's like a game of Civilization, where our Universe goes at steady pace through the tech tree, while Falloutverse rush the atom, neglecting the culture.


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

[User] Eli5: How can large companies be worth (valued at) so much when they do not make any net profit?

[Assistant]
The value of a firm is all of its future cash flows (cash in minus cash out) discounted to the present.

Getting to this value of course requires conjecture, and investors will disagree about what those future cash flows might be. Those who believe they will be higher will buy stock; those who think it will be lower will sell it. The balancing point between the two determines the price of the stock, and the price of stock \* outstanding shares is the market valuation of the company.


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

[User]
[Marvel] Could Domino alter the stock market?

If she likes a stonk, and has diamond hands with it, does it go to the moon?

I know her luck mostly affects things in her vicinity, but if she is on the trading floor wouldnt that count?

Edit: If her localized telekinesis is at play; and she is on the trading floor; when the numbers come out after the bell rings- wouldnt she affect the computers? So her stocks would show well at least for long enough for the rest of the trading floor to believe they see a rise and start buying?

[Assistant] Her power seems to hinge more on making sure she breaks even or slightly pulls ahead, versus constantly giving her ultimate success; she falls off an overpass and hits the one bouncy castle in a 10 block radius, but the castle isn't stuffed with loose cash. Her betting on the stock market would not have predictable results; her stock might be the only one not to take a shit during a sudden crash, but she might also diamond hand her way into the poorhouse and in turn get evicted from her apartment 12 hours before a cruise missile slams through her (former) bedroom window.


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

[User]
ELI5: How does fur know what color to be when it's in a pattern (like spotted)?

Like on a leopard. If fur falls out, how does the new fur know to grow in that pattern? My cat is a tuxedo and I rarely see white hair in her black fur and vice versa but I know she sheds like crazy.

[Assistant] If you shave your cat (*disclaimer: do not shave your cat*) you'll notice that the *skin* under the white and black parts is different colours. It's like that for (most) animals with fur patterns - the pattern goes all the way down to the skin. There is different pigmentation in the skin that the hair follicles grow from.


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

[User] ELI5: How can they make a Blu-Ray version of 70's and 80's or even older movies? Is it the same resolution converted bigger or actually it is better quality?

[Assistant]
Film is better quality than the DVD release, so while it may not be the same as bluray taken from a crisp 4K digital source, it's still going to be better than DVD.

Also, they do certainly do some digital enhancement, but they do it to the digital capture of the film, it's not just upscaling the DVD release.