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

[User]
[Harry Potter Films] Where was Crabb during the Battle of Hogwarts?

So I know that the actor was arrested for rioting and growing pot, but what's the Watsonian answer for Crabb's absence during the film? It seems weird that he'd be off doing his own thing and not teaming up with Draco and Goyle. Was he kicked out of school the previous year for growing wizard pot or something?

[Assistant] I would assume that he just failed out. Even with very limited screen time in the other movies it was clear that he wasn't doing well in school and even with a wand and access to magic he still mostly used physical violence to bully people.


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

[User] ELI5: Why on earth can you smeel things by inhaling but not exhaling? Are my lungs odorless?

[Assistant] They aren't, but you've literally smelled them every waking moment of your entire life.  When the brain receives a constant stimulus, after a while it will start to ignore it, since it is no longer relevant information.


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

[User] ELI5: If masturbation releases endorphins, why don't we just masturbate ourselves to happiness?

[Assistant] Not a scientist but like with any action/drug that causes an increase in endorphins, the effect is only temporary so unless you were doing nothing but masturbating, your endorphins would simple go back down and you would no longer feel happy.


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

[User]
Why does thick, goopy mustard + thick, sticky honey = thin, watery honey-mustard?

I make my own honey-mustard frequently, and it is always delicious, but I don't understand the dramatic change in viscosity.

[Assistant]
Honey is a super saturated solution of fructose and glucose with a tiny amount of dextrin. Honey also exists below its melting point so can be considered a super cooled fluid and it is viscous because of the extensive molecular interactions between the sugars this state allows. Below its melting point any change in the fluid content moves honey away from super saturation towards a more regular sugar solution and this has marked impact on the viscosity.

Almost certainly mustard thins honey because it brings with it enough water to reduce the degree of super saturation which impacts honey's viscosity.

The simplest mustards are just mustard flour suspended in water or vinegar often with an amount of starch to thicken them (either corn flour or arrowroot). Adding anything that dilutes the starch too much and prevents it from interacting with itself will reduce the viscosity of a starch thickened solution.


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

[User]
[Star Wars] How long would Luke have to stay on Dagobah in training to defeat Vader and Palpatine in a fight withouthaving to rely on Vader being conflicted? Would Yoda even live that long?

What was the plan in Yoda's mind? Does Yoda have the necessary equipment such as training droids and lightsabers? Who is he going to spar with other than Yoda to get exposed to different fighting styles?

[Assistant]
We have to remember, Luke is an absolute prodigy by all accounts.

Within a few minutes of learning about the Force, Luke was able to deflect shots from a training remote, blindfolded. Padawans who had presumably been training for *years* are shown to be performing the same training as Luke in holorecordings during the final years of the Old Republic.

With no more than a few days training with Obi-Wan, Luke was able to actively use the Force to line up a nearly impossible shot to fire a proton torpedo into the thermal exhaust port of the Death Star. Also, notably, Luke is so connected with the Force that he can hear Obi-Wan speaking to him from the Netherworld of the Force, something that both Yoda and Obi-Wan had to specifically train during their exile in order to do.

Vader himself comments on how strong the Force is with him.

Through a few years of, presumably self directed study, Luke is able to use telekinesis to wrench his lightsaber free from the ice on Hoth, and takes down a AT-AT walker through creativity and his lightsaber. Also indicative of his growing power, Luke is not only able to hear, but see Obi Wan's spirit on Hoth.

He trains with Yoda on Dagobah for an unspecified time (probably no more than a few weeks). Even though he is a neophyte in the ways of the Force, Luke is able to generate enough power to move an entire X-Wing, although he cannot completely lift it from the swamp (look at Yoda's shocked expression as the ship begins to rise from the swamp). More evidence of his growing abilities are present here, as he can not only hear and see Obi-Wan's spirit, but actively converse with him.

After a short time with Yoda on Dagobah, Luke is good enough with a lightsaber to not immediately be overwhelmed by Vader (although Vader is clearly holding back), and acquits himself relatively well for someone who has had maybe a month of formal training under his belt.

We next see Luke on Tattooine, where he has been using Obi-Wan's journals to help complete his training. During this time, he has built a new lightsaber, and has acquired enough knowledge and control over the Force to Force Choke two Gamorrean guards with a simple gesture. He also demonstrates the use of the Jedi Mind Trick, although he is unaware that Hutts cannot be influenced.

On the barge above the Pit of Karkoon, Luke demonstrates the ability to hold off several blaster wielding foes at extreme close range, and succeeds in his efforts to rescue Han and Leia.

Upon returning to Dagobah, Yoda himself states that he does not require any more training, and that he will be a Jedi once he confronts Vader and the Emperor (presumably his final test of will and resisting the Dark Side).

Above Endor, Luke is able to use his limited, self directed training to duel on even footing with Vader (although, admittedly, a conflicted Vader), and eventually overwhelms his father in a fit of rage after Vader threatens his sister. Shocked at what the Dark Side almost made him do, Luke rejects the Dark Side completely (no small feat), and refuses to bend to the Emperor's will (another impressive feat).

This obviously pisses Palpatine off, but Luke is able to resist the Emperor's Force Lightning (the same stuff that killed Jedi Master Mace Windu in about 3-4 seconds) long enough to sway his father away from the Dark Side, and fufill his destiny as the Chosen One by destroying Palpatine.

That all being said, Luke's formal training appeared to be incredibly practical and served an ulterior motive. Yoda and Obi-Wan were training Luke, first and foremost, as a weapon to use against Vader and the Emperor. Yoda and Obi-Wan even admit to as much, stating that Vader was irredeemable, and needed to be stopped in order to bring peace to the galaxy.

Realistically, Luke would have had to train for years before he would be able to stand against an all-out Vader, who was the 2nd most powerful Force Wielder in galactic history. But there are alternatives to fighting, as Luke demonstrates. Luke ultimately transcends his training and realizes that the real fight could not be won by martial prowess, but by trusting in the Force, and showing love and compassion to the one man in the galaxy that needed it the most.

Yoda and Obi-Wan's plan would never have realistically worked, they simply did not have enough time. Love (and the refusal to let go) led Vader down the dark path, and love was the only thing that would ever have led him back to the Light.


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

[User] [Zombieland] Seriously. where they hell are they getting gasoline, how is the electrical grid getting powered, the bullets, the everything?

[Assistant]
Of the three, Id say bullets would be the least problematic. The apocalypse happens pretty rapidly so less time for people to panic buy, hoard or waste too much ammo. There should be an abundance of bullets available in abandoned stores, homes, logistics centres and Army/National Guard/Naval/Air bases.

Gasoline starts going bad pretty quickly. Some say as little as 6 months but probably a little longer if youre not concerned with peak performance or if its going to knacker your engine with prolonged use. However, as Zombieland 2 takes place aroun 5 or 6 years after the first movie running a monster truck on stored gasoline seems a stretch (I guess it could have been converted to some other fuel sourcemaybe).

Electricity from the grid seems far fetched. Even assuming nuclear power stations or hydro-electric, without maintenance theyd either shut themselves down or fail (possibly spectacularly).


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

[User]
[PacMan] If Power Pellets make PM stronger to eat ghosts then why can revived ghosts kill PM whilst the Power Pellet is still in effect?

I'm sorry if this is corny, but I've been playing some pacman games again after 30 years, and it seems odd.

[Assistant] The Power Pellets cause Pac-Man to phase at a different frequency, which allows him to disrupt the ghosts' cohesiveness.  The ghosts however have the ability to adapt to these new frequencies after a short period of time.  However, once they encounter the changed frequency, they can adapt immediately upon respawning.


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

[User]
Why do abusive parents abuse some of their children but not others?

I have my own observations based on anecdotal evidence, but I would like to hear what research has to say.

[Assistant]
Bowen's family systems theory has some of the answer. Basically, you're born into a position that has an implicit script associated with it. Older brothers will always be older brothers, youngest sisters will always be youngest sisters. Abused kids grow up, seek out other people who they feel they can relate to, and clean up the abuse they received but still do a good amount of harm to their kids.

Often, you see families set up a "good child" and "bad child" that follow from how their system is set up. Think of an overly authoritarian parent who has kids that respond by being pretty passive. These kids might discourage their own kids from being authoritarian, not seeing how they could be harming them because they're responding to their own pain instead of what is best for the kids.

Hurt people hurt people, and abuse can be on either side of a pole. Too much of one thing leads to too little of it. On mobile now, but Bowen's stuff is available for free online. Highly recommend.


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

[User]
CMV: People protesting Nike and Kaepernick might actually have a point (even though I disagree with them and support Kaepernick)

So I think the core issue boils down to a fundamental misunderstanding about what both sides view the American flag as. Pro-Kaepernick say the flag and anthem represent America as it is today and how it treats minorities. Anti-Kaepernic say the flag and anthem represent patriotism and that disrespecting the flag disrespects the country, and more specifically, veterans.

I personally think that any sort of flag burning or peacefull protest is 100% ok. Youre not hurting anyone and its better that the alternatives. Namely, just sitting back and taking it or violent protests. However, are we gonna sit back and pretend like they are all just dumb hicks and ignore the fact that the world is filled with powerful symbols that most people use to make sense of the world? In fact, most of the people Ive run across in the real world who are anti-Kaepernick are veterans or are the family of veterans. Most militaries break down their soldiers to their base and build them back up with an unwavering respect for the flag and the country. The US is no exception. Are we going to act like the flag and the anthem arent core parts of their identities?

What if every time the westboro babtist church had a "God Hates Fags" rally I had a couple of gay dudes cum on a bible in protest? What if every time isis did some horrific act I took a Quran, put some slices of bacon in it, then put it in a panini press in order to protest them? Of course the radicals would be upset. But wouldnt some reasonable people who take these symbols very seriously be upset as well?

Im not saying I agree with them. At the end of the day a flag is just dyed cotton. Holy books are dead trees. An anthem is just a dumb song. But these things mean different things to different people. I support Kaep 100% but can we agree the other side at least has a point?

[Assistant]
Each branch of the military have their own flags, the US flag is not a symbol that represents the military it represents the country. It's a common rhetorical tactic for conservatives to deflect any criticism towards the troops.

You hate the war? You hate the troops!

You want socialized healthcare? Fix the VA first and stop complaining!

You want the minimum wage to be higher? Soldiers don't get paid enough and their jobs are harder!

You think homelessness is a problem? Don't help any alcoholic bum when their are patriotic veterans on the streets!

These deflections are whataboutism at best and are not worthy of response until the argument they are a distraction for is addressed first.


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

[User]
[DC] Why exactly would a Suicide Squad need Harley Quinn?

In every lineup I've seen her in she's always the weakest link. She isnt a meta-human, she doesnt have any formal martial arts/marksman training (even when she demonstrates this there are usually two people on the team that are better than her in these regards), and outside of being a former psychiatrist she doesnt seem very insightful. She's just eye candy and extra muscle. It doesnt help that she's a basket case. I know the Suicide Squad is suppose to be expendable, but each member should still be relatively useful. I didnt wake up this morning planning to shit on Harley Quinn but who could be a worse choice?

[Assistant]
>She isnt a meta-human, she doesnt have any formal martial arts/marksman training

Neither is the Joker and he's a citiwide disaster every time he escapes Arkham. In comic book world being crazy is a super power.

Harley is basically joker-lite who's a bit more on the side of reasonable.

Another benefit: on a team full of insane villains she is both a psychologist AND insane herself and close enough to the anti-hero side than the pure villain side. She's the psycho-whisperer and group glue, the one most likely to get killer croc to stop eating the other teammates.


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

[User] ELI5:  What does it mean when China keeps the yuan "artificially cheap"?  Why would they do this, and how does it affect us?

[Assistant]
Mechanically, China limits the amount of foreign investment dollars that can flow into China and the central bank buys foreign assets such as US government bonds.

China does this to fuel export growth.  A cheap yuan allows China to produce things more cheaply.  Conversely, this artificially lowers the standard of living in China because the benefits of growth are being channeled into growing exports rather than on domestic spending.  Think about this simply: because the yuan is cheap, we pay a Chinese worker say $5 a day.  If the yuan were "fairly" valued, this would work out to more like $9 a day.  The Chinese worker would be much better off, but Chinese exports would become more expensive, disadvantaging Chinese export-based firms.  The extra purchasing power of the worker would help Chinese firms focused on domestic consumption.

It affects us in the opposite way that it affects China.  Basically, we get cheap trinkets, iPhones, etc. manufactured in China, but it decimates our manufacturing and export industries.  So this scheme is useful for the individual consumer but bad for a lot of industries.  Obviously, people are employed by businesses, so these things are related.  Economically speaking, these two forces should balance each other out through exchange rates, but China doesn't allow the yuan rate to change properly, so we have too many cheap Chinese imports, which is good for American consumers but bad for American businesses (which in turn is bad for consumers because they have to work somewhere).


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

[User]
[The Time Machine (2002)] Whose bright idea was it to blow up the freaking moon?

I mean, what the fuck man. Why use experimental explosives to build what are essentially luxury homes on the moon when we've got the tech to maintain a regular lunar flight??

[Assistant]
>Why use experimental explosives to build what are essentially luxury homes on the moon when we've got the tech to maintain a regular lunar flight??

Why use a toxic fossil fuel to power the world when we've had the technology to get off it for almost 50 years? Humans do stupid shit for the almighty dollar.


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

[User] ELI5: How can tensions between the USA and Russia be so high, yet the latter still allow the former to use their rockets for ISS missions?

[Assistant] Even going back to the Soviet days there has been a lot of cooperation between us the the Russians/Soviets in non-military scientific ventures. Scientists don't care about nationality, they care about peer-review and accurate data. Unless a shooting war broke out, and the governments directly halted cooperation between the two nations' scientific communities, the scientists of our nations will continue to cooperate on projects and research. They just don't care about the politics.


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

[User] [AMC's The Walking Dead] Why does the walker girl pick up the teddy bear in the Pilot?

[Assistant]
Walkers have trace memories. The man with whom Rick first stayed saw his wife as a walker. Although wandering aimlessly in the street among other walkers, she eventually approached the house and looked in the eyehole.

It appears that transformation destroys much of the brain, but not all.

This also explains why walkers occasionally form herds - trace memories and social animal instincts.


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

[User] [Looney Tunes] Looking to invest. How's ACME Industries' stocks performing?

[Assistant] Through the roof, then through the floor, then through the roof, then through the floor, then through a boulder with a train tunnel painted on it, before leveling out for a comically untenable amount of time, and finally plummeting straight down.


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

[User]
Getting into research with low GPA

Hi all,

I am in my final year of undergrad (Biomedical Sciences). I want to get some opportunity to volunteer or work in a lab to get some lab experience before I graduate. But my low GPA stops me from approaching professors and I know I won't be chosen since I am not one of those exceptional students that professors look for when choosing from applicants.

If I want to describe myself then I would say although I am not so super smart but I am quiet hard working. I would learn but take my own time. During high school my grades were 90+ which I achieved only because I sacrificed my sleep, social life and all other entertainment. I am not one of those people who can balance study and social life and the reason is because I learn slow and I review concepts till I feel satisfied enough to confidently say that I know this stuff now. My initial years of undergrad were amazing in that I was pushing myself consistently. Although not an exceptional GPA (had 3.3/4) but I was still considered as "good student". But after the pandemic hit, my mental health suffered a lot (really a lot) and my GPA fell down considerably (currently around 2.9/4). I struggled to get out of bed and was totally directionless and lost. There was this guilt of not doing what I need to do and at the same time I didn't bother about just anything! I did find support later and now somewhat better in terms of mental health but now I have other health issues which keeps me away from giving my best. To be honest, before pandemic the lowest grade I got was C+ and that too in just one course. During pandemic, when I was not at my best, I had a couple of D's too. At present my GPA isn't at its best that I could go and talk to my professors regarding a research position. I know myself well and I know that those D's that I see on my transcript is not me. But I guess when professor will see my GPA and especially those D's I will be pushed out.

Anyone here can give me suggestion on how can I approach professors, how do I convince them that I can do better and more importantly what will make them choose me over others despite a bad GPA for lab position???

[Assistant]
I think most professors understand that GPA is not a good indicator of research aptitude. Many of them probably had less-than-stellar GPAs when they were undergrads. What they're looking in undergrads is not book-smarts. They want to see passion, hard-work, ability to listen, and an overall good lab citizen.

So start emailing professors to see if you can join their lab. You'll be pleasantly surprised.


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

[User] [Aliens] Why did every single person go down to LV-426 from the Sulaco? Wouldn't it have made sense to at least leave one person on board to report in on how the team we're doing or say, send an extra ship down if needed?

[Assistant]
Unnecessary, and a waste of resources besides. The *Conestoga* class troop carrier was fully capable of operating independently as an observation platform, recording all of the data feeds and reports from the surface team for later perusal. Further, all that the ground team needed to do to call down an additional dropship was simply remote-pilot it down via the communications link in the unit APC.

The ship is much better on its own at doing everything that needed doing while in orbit than a human crewmember would be, *and* it doesn't need to waste power keeping the crew decks heated. Plus-plus, it saves on the hypersleep costs for a human that wouldn't be of material use to the actual mission that needs doing.


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

[User]
Why do quarks have "charges," and how does this work?

I know that protons have a +1 charge because of their constituent quarks (+2/3, +2/3, -1/3), but I was curious as to what forces cause quarks to have these fractional charges and how it works.

[Assistant]
Rather than forces creating charges, charges are what specify how forces interact with particles. Here we're talking about electric charge, which is usually defined in particle physics so that the electron has charge -1 (with no units). Then the fact that up-type quarks have charge 2/3 means that, in an electric field, they experience a force 2/3 as strong and in the opposite direction when compared with electrons. Down-type quarks experience a force in the same direction as electrons but 1/3 as strong.

Electric charges are not forced to be integers or fractions, but we observe that all the particles we know about have integer or fractional charge with a small denominator (relative to the electron charge). Even more surprisingly the fractional ones are never found alone in nature---they always are joined together (confined) into integer-charge particles. HOWEVER the reason they are confined has nothing to do with their electric charge, and everything to do with their *color* charge, which relates to the strong interaction. It's a pretty interesting arrangement that is potentially explained by grand unified theories that join all of the forces, including color and electromagnetic, together.

As a bonus fact, note that electric charge is special among the fundamental forces and charges in the Standard Model, because it's the only one that isn't *forced* to be quantized (come in integer multiples, in this case multiples of 1/3). (It *happens* to be, experimentally.) Mathematically this is because electromagnetism is defined by an abelian gauge theory, which allows any charge, while the weak and strong forces are non-abelian gauge theories which only allow fixed units of charge. Grand unification puts the abelian part of the Standard Model inside a larger non-abelian group, forcing the charge to come in fixed units.


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

[User] ELI5: How did the spinning red, blue, and white barber pole get synonymous with barber shops?

[Assistant] Barbers way back in the day used to practice bloodletting (cutting to release blood) as a treatment for certain illnesses. The red represents the dripping blood. The pole used to represent that has stayed with the image of being a barber.


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

[User]
[General] Would flame throwers work on force fields?

Every different sci-fi universe has a different kind of force field, but take something like a "kinetic barrier" since fire is is mostly thermal energy wouldn't it just pass right through?

Is there any universe that uses flame throwers as an effective way to pass through force fields?

[Assistant]
Well, the tricky thing there is that a flamethrower doesn't really throw fire.  Rather it throws a burning fuel source, which is an object with kinetic force.

So, all else being equal, the heat from the fire would probably pass through a kinetic barrier type, but the fuel itself would splash off the shield, making it somewhat unlikely anything behind the shield would actually ignite.


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

[User] [Lotr The Two towers] Why is the Forbidden Pool forbidden?

[Assistant]
Henneth Annn is a sacred place to the rangers of Ithilien. The location of the refuge is a closely guarded secret, because it provides protection from the dark forces of Mordor. That is why the punishment for entering it is so harsh.

Entering the refuge without permission by the rangers is punishable by death. Even if an outsider accidentally discovers the location he would still be subject to that punishment.


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

[User]
[The Walking Dead] Howcome Zombies lose all aggression with no teeth or arms?

Hey there!

I noticed Michonne chopped off the arms and jaw of some zombies and suddenly they lost the urge to eat her.

Am I to believe that the urge to kill and eat is found within the zombies teeth?

:)

[Assistant] Zombies have a very simple understanding of themselves and the world around them.  They know to bite and claw.  Once they know that they can't bite and claw, they stop trying to bite and claw.  In season 3, episode 3, Milton Mamet addresses this trait, although it is Michonne who first discovers it.


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

[User]
Is there a technical term to this phenomenon?

You're browsing your favorite news site when you come across an article that directly relates to your field of expertise.

"Sweet," you think as you excitedly click on the link, "It's really cool to see a complex field like this being covered on such a popular news site."

When you start reading the article, however, it quickly becomes clear that the issue at hand has been drastically oversimplified and watered down.

Disappointed, you realize that this article doesn't really paint an accurate picture of the true complexity and nuances of the issue. So, you click on to the next article.

This article -- completely unrelated to your field of expertise -- is super interesting, and you feel like you have a significantly better understanding of the issue after reading it.

You're a pretty smart person, but you failed to recognize that if the topic of your expertise has been so grossly misrepresented, what reason do you have to believe that the other topic has not been misrepresented in a similar fashion?

Did you just fall victim to a psychological fallacy? And if so, what is it called?

Thanks for your help -- it's on the tip of my tongue, but I just can't seem to remember!

[Assistant]
I think you are thinking of the Dunning-Kruger effect.

Basically you have to be competent at something before you can realize how incompetent you are at it. Somebody with a little bit of knowledge in something knows just enough to think they know about whatever it is, but not enough to know where they are lacking in understanding.

If you want to get stereotypical... think of like a sophomore psychology major. They know just enough about psychology to think they got it down when really they don't fully realize that there is so much more that they don't know.


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

[User]
ELI5: How common are traumatic 'triggers' in the general population? Are they really dangerous?

I'd love to understand this subject better from a psychiatric perspective, especially with reference to any relevant literature.

PLEASE: don't debate the merits of trigger warnings! Follow the subreddit rules!

[Assistant]
basically a trigger can be anything that reminds you of some traumatic event. we'll ignore the entitled tossers who misapply the term to mean "things that make them a little upset" and stick to the actual psychology.

basically when you experience a really traumatic event it changes your brain, not in a permanent way per se there is therapy and such to change it back but the trauma is part of your memory and when the fear centre of your brain encounters that memory it freaks the fuck out and you are back in that life or death situation beating the shit outta a waitress who just dropped a tray behind you.

reasonably though a trigger can be anything, a color, a song, a smell, a sudden noise and part of therapy is getting past this, usually through immersion therapy (introducing them to the trigger in a controlled environment so the brain stops associating that thing with imminent death or getting raped and starts associating it with nice things, so when it comes up your brain doesn't go straight to red alert.)


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

[User]
Eli5: why are submarines cigar shaped but jets pointy?

Both water and air are fluids but jets and missiles are pointy whereas submarines and torpedoes are cigar shaped. Why is that?

Edit: Grammar

Edit2: why is pointy better for supersonic? Why is round better for subsonic?

[Assistant]
Air is a compressible gas whereas water is usually a non compressible fluid. The air density vs water density is also very different. With those two variables the dynamics at each medium are widely different, and hence you have the hydrodynamics and the aerodynamics.

Making a submarine very pointy creates a weak structure that will not be able to whitstand the compression deep under the sea, and it will also make the submarine hard to steer because of its relatively slow speed (compared to airplanes).

An airplane with a cigar shape is actually possible (as long as it has wings) and those type of designs are used for slower and bigger cargo planes. High speed jets require a geometry that allows them to break the sound barrier more easliy, and thats the main reason for the pointy geometry. Air is usually considered uncompressible at subsonic speeds, once the speed of sound is reached, the air resistance becomes exponentially more "thick" and the calculations for the aerodynamics start considering air as a compressible fluid. A plane can be made to be good at subsonic speed or good at supersonic speed, but not the two at the same time. Pointy geometry is good at supersonic speed.


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

[User] ELI5: What's the deal with Google Inc and Alphabet Inc? Why a holding company?

[Assistant]
It breaks up the financial burdens and responsibilites of the company making it possible for the company to engage in outside endeavours without endangering its core products.

Google is Google. However Google is becoming so big, that they can't manage everything under the Google branding without some level of additional headroom to cover everything, especially logistics for a company with 70 different departments.

So Alphabet controls its lesser products and R&D that has developed over the past few years that doesn't deal with the core product of Google. Things like Google Docs, Google Search Engine, Google Adwords... those are all still under the Google brand name.

However, products like Google Glasses for example, are lesser quality products that didnt take off, yet still provide a revenue base and need support. Thus, financial resources don't get diverted from the main company directly for Google Glasses, and legal concerns also stop with Alphabet Holdings instead of Google having to deal with it personally for every single project.


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

[User]
CMV: a fine of $50-500 for accidentally killing pedestrians, and cyclists isn't enough of a penalty

For some reason, the typical penalty for accidentally killing pedestrians, and cyclists is on the order of $250 to $500 with penalties sometimes being as low as $50, and as high as several years in prison.

It doesn't seem to matter if drugs, or alcohol were involved, or if the driver was known to be texting at the time - the penalty seems to always come down to between $250, and $500 in Toronto, Vancouver, NYC, and other cities in North America.

As long as you stay at the scene of a fatal accident, and are pleasant, there seems to be a good chance that you'll walk away with nothing more than a verbal warning. Of course, being intoxicated will potentially lead to drunk driving charges, but, other than that - who knows?

Earlier this year, in Vancouver, a cyclist was killed after being doored by a driver - the driver received a fine of $81 since the offence that they'd committed was unsafely opening a car door under the Motor Vehicle Act.

In 2017, in Toronto, a 70 year old man was riding his bike when he was suddenly cut off by a driver who turned right directly in front of his path, leading to the cyclist being knocked off of his bike. He died of a traumatic brain injury 2 days later, and the driver was fined $500 - the maximum allowed penalty allowed under the Highway Traffic Act for an unsafe turn.

In 2017, in Toronto, a woman was standing on the sidewalk, and was fatally struck by the driver of a van that mounted the sidewalk - the driver received a fine of $1000, and six months of probation with a few driving restrictions attached. The lawyer who litigated the case noted that of the previous cases he'd litigated, drivers were convicted of careless driving, or a lesser charge, and fined $700, $600, and $85, respectively.

So, Reddit, change my view - is a small fine enough of a penalty?

Of the several hit and runs I've been involved in, nothing's happened to the *presumably drunk* drivers - however, to be fair, my bike has never been severely damaged, and I didn't die in any of those collisions - so, no harm no foul.

[Assistant] Results-oriented based punishment rather than intend-oriented has no benefit in reducing harm; it has no deterrent benefit since punishing higher based on situations outside of the culprit's control can't rationally deter them; as they no control over whether it will happen by definition so from their perspective from a matter of strategy it's random. In terms of rehabilitation it also adds nothing, and one might even argue that from a perspective of retribution it's unfair to punish some more than others though they did the same thing because the consequences were worse due to circumstances outside of their control.


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

[User]
[Halo] Why are some of the human weapons so crap?

The flamethrower fielded by the UNSC (the usefulness of such a weapon a separate issue) has absolutely pathetic range and weighs an absolute tonne, forcing the player down a great deal. A WW2 era flamethrower had a range of up to 50m, and was nowhere near so heavy.

More surprising is the shotgun, which has somehow been made to have almost no range at all, and is still pump-action only. By the third game has only a 6 round magazine, whereas a modern KSG can hold up to 15.

What made humanity drop the ball so hard and forget how to make a decent urban assault weapon?

[Assistant]
The flamethrower that the Master Chief is recorded as having used in the battle of Voi isn't actually a flamethrower made for combat but an industrial strength mobile incinerator. These were made for mobile decontamination and burning through obstacles, they were intended to be used at close range and be mounted on a heavy lifting exoskeleton. It was only thanks to the Master Chief's enhanced strength and protective armor that he was able to use it as a weapon.

As for the rest of the weapons, a big issue that humanity faced when first encountering the Covenant was that weapons designed for killing other humans had great difficulty penetrating covenant armor, and could rarely penetrate energy shields. Weapons had to be adjusted to fight this new enemy by firing fast enough to overwhelm them or by increasing the power of the weapon. The shotgun is a case of the latter, by increasing the power and size of the rounds it uses it is able to effectively penetrate covenant armor and shields at close range in a fairly devastating way, but it can only hold a few rounds and the recoil is such that it is much slower to fire.


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

[User]
ELI5: How can light not escape a black hole

If light is made of photons, and photons have no mass how does a black hole's gravitational pull affect said light?

[Assistant]
Gravity does not come solely from mass. That may be what Newton thought, but as it turns out, it comes mostly from energy, and matter is a type of energy.

Light is not matter. But it *is* energy, so it is affected by gravity.

When body A orbits body B at a particular height, A must circle B at the correct speed to stay in that orbit. Lower orbits are faster orbits, and vice versa. With black holes, there is a particular height(called the Event Horizon) at which the orbital velocity is the speed of light. If anything is closer to the black hole than that height, it cannot orbit, and will inevitably spiral to the center.


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

[User] [Green Lantern] What specific power does each lantern ring give?

[Assistant]
All of them give relatively similar powers, but some have more unique properties than others.

All of them grant the ability to travel safely through space at superluminal speeds, including a personal force field that provides life support, universal translation, and the ability to create beams of energy that can be shaped according to the wearer's desire. The further they are from the "center" of the spectrum with green, the more influence they exert over the wielder-- yellow and blue rings mostly amplify tendencies that are already there, while red, orange, indigo, and violet rings can dominate the wearer's personality entirely.

* The energy produced by red rings is highly corrosive and intermingles with the blood of the wearer, forming an acid-like substance they can spew from their mouths in battle.

* Orange rings steal the identities of those the wearer kills, enabling them to create and maintain constructs of those entities that serve them, and can absorb constructs from other rings to replenish their energy.

* Green and yellow rings don't have many unique abilities, but offer a greater degree of fine control that is extremely difficult with other rings.

* Blue rings are the hardest to create constructs with, but are highly adept at healing and can create a feedback loop with green rings that supercharge both, and can dampen the influence of red, orange, or yellow rings, as well as create images that reflect the hopes of a target, as well as recharge from the hope of those around it.

* Indigo power rings reflect the abilities of other rings they're in close proximity with. They also heal, but can also cause pain to those who have caused pain to others, and can teleport over extreme distances.

* Violet rings have similarly precise control to green and yellow rings, and can also create crystals in which a living being can be held in stasis and slowly shaped into an ideal wielder for another such ring. Their constructs are immune to the absorption ability of the orange ring. They can also teleport and resurrect the recently deceased by drawing power from the heart of someone who loved them.


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

[User]
CMV: The idea of food deserts is overblown and does not deserve to be used as the first or primary argument against why obesity is more prevalent in lower SES from a macro perspective

CMV: The idea of food deserts is overblown

CMV by providing specific examples, that we can go through together on google maps

Inevitably, when the topic of obesity in lower SES comes up, food deserts is one of the first things mentioned, but why?

6.2 % of Americans live in a food desert. With the generous assumption that most individuals living in a food desert are living in poverty, we know that 80 % of Americans living in poverty own a car, and a fair assumption is that most of that 80 % has insurance and gas money. But let's again be generous and say of that 80 %, an additional 20 % do not have access to insurance or gas money, so let's say 60 % of Americans live in poverty and own a car that they can regularly use.

So basically only close to 1/3 of that 6.2 % of Americans that are in a food desert actually do not have access to a car with gas and would have to use terrible public transit that could take them 30 mins to 1.5 hours to reach their grocery store. Something that affects basically 2 % of Americans should not be used as the primary example of why obesity is an issue in lower SES. It makes no sense.

When I've looked at the examples I could find online on google maps, there's usually a Walmart or Walmart equivalent usually just a 5-15 mins car ride away.

So how to change my view?

1. Find an example of a food desert in which it takes > 30 mins to reach a grocery store *even by car*
2. Poke holes in my logic, remember most of the assumptions I've made actually serve to actually work against my core premise

Ninja edit: forget obesity being more prevalent specifically, let's just stick to "why obesity can be an issue in lower SES"

[Assistant] There is one small grocery store on the Spirit Lake Nation, in North Dakota. Its next to the casino. It really doesnt have a lot of fruits and vegetables. If you live in the other side of the reservation its way more than 15 minutes. There is a Wal-Mart about 10 miles from the reservation but its probably 15-20 miles if you are on the opposite side of the reservation from the town of Devils Lake. Also, youre not talking a highway from Warwick to St. Michael or Devils Lake. If its not snowing, if theres no ice on the road, if you have a car and gas, you can get there in 30 minutes . When the weather is bad, double that. There is no public transportation. This is one example and Spirit Lake isnt a very big reservation at all. Take a look at Standing Rock or the Navajo Nation for even more rural areas.


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

[User] ELI5: When you take a particularly harsh bowel movement, why do you get that brief rush of pressure to your head?

[Assistant]
You've got a very long nerve in your body that runs all the way from your brain down to where you poop.  When you bear down (push really hard to get the poop out) you can stimulate that nerve.

That nerve happens to be in charge of some very important stuff in your body, like telling your heart to slow down, telling your blood vessels to dilate (reduce your blood pressure) ect.  So when you stimulate that nerve by pushing really hard on a big poop you sometimes make it cause those things when you don't need them to happen.

So suddenly your blood pressure goes down and you feel it first in your head (cause gravity, and your brain is important).  This sometimes causes people to pass out.

This is the Vagus nerve and the term often used is a "vasovagal response" meaning your vessels responding to your vagus nerve. Or even "vasovagal syncope" which means temporary loss of consciousness that resolves quickly due to vagus nerve stimulation.


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

[User] [Star Trek] Is Q aware of the mirror universe?

[Assistant]
He most likely is aware that it exists (since he's basically omniscient and can travel anywhere in the multiverse with a snap of his fingers) but doesn't visit it because he finds it repellent.

His entire motivation to interact with humanity (and particularly Jean-Luc Picard) in the main timeline is to poke us and prod us along a certain path which will ultimately lead to us becoming morally superior beings that evolve into a species very much like the Q themselves.

He chose Picard as his main "test subject" because Picard has a strong moral code backed by deeply-held beliefs and philosophies. Q wishes to test how firm Picard's morals are, and to put him in situations where he has to learn certain "truths" that Q believes humanity needs to accept in order to continue their journey down the path he wants them to go.

The Mirror Universe is the antithesis of what Q wants humanity to become. Instead of morally superior beings, humans in that universe are crabs in a bucket, constantly pulling each other down simply for the sake of chasing personal power and fulfilling their basest animal urges, without any concern for who they hurt in the process.

Q can't set that version of humanity on the path to becoming like the Q. It would be disastrous for the multiverse. Therefore there's no need for him to interact with them, and at any rate, they wouldn't be any fun for him to play with.


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

[User] ELI5: What's going on when i get the pins and needles feeling in my hands and/or feet?

[Assistant] Most likely you've put pressure on a nerve and this is blocking its ability to signal correctly.  Different nerves turn back on when the pressure is relieved in different orders hence you'll feel burning sensations, prickling, etc as the nerves fire back up and do a sort of test run.


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

[User] ELI5: Why do back scratches feel so good while tummy scratches feel weird and awkward?

[Assistant] Its because the stomach is a vulnerable and exposed part of the body that stores visceral organs.  Think of when a lion attacks its prey; it goes for the neck or rips out the entrails in the abdomen.  Tickling is a way that parents cultivate the defensive/aversion tactics of protecting these areas in the baby.


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

[User]
[Pokemon] How are small pokemon like pidgey able to use fly?

Do they simply lift their trainers with massive windgusts? Temporarily grow bigger? Call in a favor from their bigger bird uncle? I need somewhat legit pocture of this in my head.

[Assistant]
It's suggested that the smaller ones (or those oddly shaped) that cannot carry a human on its back will instead allow a human to grab on to its legs as it takes off.

It will vary from Pokemon to Pokemon, as some will use the above method, and some will instead grab the Trainer with its claws/arms/legs/beak/etc and carry them to their location. Most Pokemon will carry Trainers on their back (such as Pidgeot and Golurk), but the others that can learn Fly will have some method of grabbing the Trainer, being grabbed, or telekinetically carried as they take off.


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

[User]
[VTM] Do vampires smoke just to look cool?

No breathing, presumably they don't fall prey to nicotine addiction, yet lots of vampires smoke.

[Assistant]
It's something they can do that feels good that isn't assaulting people. A lot of mundane pleasures get ruined by becoming a VtM Vampire. They can't go for a stroll in the daylight, most opportunities for socializing with normal people are messed up by their hours and their struggle with their impulses, and they can't eat normal food anymore. Smoking, meanwhile, is something they can not only still do, but do as much as they want with no fear of the consequences; a vamp would have to wrap their lips around a coal plant exhaust to inhale enough smoke to hurt them.

If they never smoked before, the sudden lack of consequences makes it more appealing. If they did smoke before, then continuing to do so is one of the few things from their mundane life that can continue uninterrupted.


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

[User]
Why do we need to postulate the presence of dark matter? Wouldn't unexpected astrophysical phenomena simply indicate that our understanding of gravity in inadequate?

It seems to me to be a great jump to postulate the existence of a new type of matter in response to astrophysical observations not lining up with predictions as dictated by current theory. Would not the more parsimonious response be to work on modifying the theory? Do we really need dark matter to explain our observations?

[Assistant]
People seem inordinately bothered by dark matter.  Dark matter is evidence that our understanding of gravity is good, not the other way around.

Let me begin with another situation.  You hear your doorbell ring, yet when you go to look, there's no one there.  Do you suppose that there must be something new electrical force that only shows up in doorbells or do you figure somebody rang the bell and then left?

Or imagine you see a star's light showing oscillations in its wavelengths, up a little bit then down a little bit, in a regular pattern.  Do you imagine that these particular stars are governed by some new force observed nowhere else in the universe, or do you figure that you've detected the influence of a planet -- which would produce exactly this effect as it orbited the star -- even though you don't have an actual image of the planet?  That's exactly how the first exoplanets were discovered.

Or imagine you see a loss of energy and momentum in a decay process.  Do you imagine energy and momentum conservation should be tossed aside, or do you recognize that there is a particle you've not overtly detected carrying that energy and momentum?  That's exactly how the neutrino was discovered.

Or imagine you see the stars near the center of our galaxy undergoing elliptical motion around nothing that you can see.  Do you suppose there is something wrong in our understanding of motion, or do you conclude that there is a massive object you can't see at the center of our galaxy, around which things are orbiting?  You conclude the latter, and have evidence for the black hole at center of the Milky Way.

Dark matter is evidence that our understanding of gravity is really, really good.  Remember, general relativity has survived a range of tests, from the orbital mechanics of the solar system and tides on Earth all the way up to cosmological behavior of the universe and the merger of black holes.  Positing dark matter *is* the parsimonious approach, because it turns out that we can explain a host of phenomena--the motion of galaxies, the motion of stars within galaxies, gravitational lensing around galaxies, and features of the cosmic microwave background radiation--if there is additional matter that interacts gravitationally but not otherwise (or perhaps also via the weak force).

If our models of gravity were wrong, positing dark matter would not be expected give us results consistent with all these quite varied observations.

I'll add that we know that not every particle feels every force -- electrons don't feel the strong force, for example--but every kind of object is subject to gravity.  Therefore, there is nothing particularly peculiar about something that does not interact via any force other than gravity.  (And, since dark matter may interact via the weak force, that would put it in the same category as the neutrinos, which feel the weak force and gravity, but not the strong or electromagnetic force.)


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

[User] ELI5 Why are some areas of the human body hairier than other areas?

[Assistant] Mainly heat retention. You lose the most heat through your head, arm pits, and groin. Hair retains that heat and thats important bc it takes a lot of calories to keep us warm in a cold environment. Additionally, you usually have more hair on the front of your legs/arms bc those face into the wind while on the move. Hair can also serve as tactile perception for when a bug is crawling on you or goosebumps occur. Hair around the eyes keeps dust and sweat out.


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

[User] Do we currently have any precautions installed in case an asteroid starts heading towards Earth? If so, what are they?

[Assistant]
I believe our best defence is a last minute crash course for some oil workers to drill a nuclear weapon into said asteroid and blow it up.

Realistically we have detected most of the planet killers around us, we think. Reasonably sure we have detected the speicies killers. Everything below that is still an open question.

As to stopping something if detected? Some plans exist but nothing concrete. Nukes are generally considered a bad idea, but given enough time the best bet is to try to nudge it out of the way.

Best hope is decades of warning.


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

[User] Where do electrons get their seemingly constant supply of energy to orbit a nucleus without slowing down?

[Assistant]
Electrons do not radiate electromagnetic radiation if they are already in the lowest available energy state. So, for example, an electron orbiting a proton in the hydrogen ground state has nowhere lower to go, so it cannot emit a photon. Therefore it doesn't loose energy, and can keep orbiting forever.

You might ask, "why can't the electron just fall onto the proton and just stop orbiting? Why isn't that the lowest energy state?" The answer is related to the Heisenberg Uncertainty Principle. If the electron stopped orbiting and fell into the proton and stopped, then its position and momentum could be known better than is allowed by the uncertainty principle. So its wave function has to spread out some, in sort of a "halo" around the proton. It's actually a philosophical question whether the electron is literally "orbiting" the proton in its ground state; all we know is that the lowest energy wave function is spread out around the proton, and that the electron cannot emit a photon because that would imply loosing energy, and there is no lower energy state for the electron to occupy.


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

[User]
Why is alcohol measured in proofs?

I understand that a proof is double the percentage of alcohol by volume, but if that measurement is a universal rule, why not just use percentages; why use proofs at all?

[Assistant] From the 18th century until 1 January 1980, the United Kingdom measured alcohol content in terms of "proof spirit", which was defined as spirit with a gravity of 12/13 that of water, or 923kg/m3, and equivalent to 57.15% ABV.[1] The term originated in the 18th century, when payments to British sailors included rations of rum. To ensure that the rum had not been watered down, it was "proved" by dousing gunpowder with it and then testing to see if the gunpowder would ignite. If it did not, then the rum contained too much water and was considered to be "under proof". Gunpowder would not burn in rum that contained less than approximately 57.15% ABV. Therefore, rum that contained this percentage of alcohol was defined to have "100 (one hundred degrees) proof".


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

[User] ELI5: How do Dyson air fans work and why do they use a ring-shape structure? How are they better than a normal air fan?

[Assistant]
that there is still a fan in the base. Being in the base, in a housing, it is a fucted fan ans is more efficient because air isnt lost around the blade tips. From there, the air goes into the ring manifold and escapes through a slit inside the ring. This high velocity air lowers the pressure inside the ring and draws more air from the leading area, increasing air volume.

Advantages : more efficient fan, fan case makes it quiet, laminar flow travels farther across the room.


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

[User]
Moral complications aside, was China's one-child policy good from an economics perspective?

Basically I would like to understand whether it made sense to have fewer children with a higher standard of living despite the inversed population pyramid that is now developing.

Thanks in advance.

[Assistant]
If you don't maintain the population then the ratio of workers to retirees won't be enough to support the welfare system.

More than that, the amount of resources available are not finite. More people means not just more mouths but also more workers. Human capital is one of the biggest resources, if it's skilled.

It's not how many people or resources there are, it's how you organize and utilize them that matters.


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

[User]
[Star Wars] Are the Jedi and Sith honor bound to battle with lightsabers and the Force or could they just bombard a planet from orbit if they knew their opponent was there?

Like what would Vader have done if he had found out Yoda was on Dagobah?  Would he have to fly down there, engage in a cryptic taunt battle about who's the bigger fool, brag about the power of the Dark Side, blah blah blah, and get his cape all muddy?

Or could he just drop a few nukes and go home?

[Assistant]
> or could they just bombard a planet from orbit if they knew their opponent  was there?

I believe the correct term is "wipe this pathetic planet from the face of the galaxy" and Darth Malak does exactly that when he thinks Bastila is hiding on Taris.


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

[User] ELI5: It's been estimated that women are twice as likely as men to experience major depression. It's also estimated that men are 3.5 times more likely to commit suicide compared to women. How does that work?

[Assistant]
Suicide *attempts* are actually about equal between the sexes. *Deaths* from suicides are where men outnumber women. This mostly has to do with the methods chosen. Men have a tendency of picking more violent and sure ways of committing suicide (such as guns), whereas women more often attempt to commit suicide through more uncertain methods such as pills or slicing through wrists.

There are a whole load of hypothesis on why we see those different methods, some having to do with access (more men have guns, so they also have them more available to commit suicide with) to socialisation (the idea that women are more socialised to not cause a big fuss / mess, and therefore also chose suicide methods that will lead to a more intact corpse, which can be seen as, well, literally, not causing a mess i.e. less clean up)


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

[User] [Cookie Clicker] What exactly is the Cookieverse? How do the portals work? What is the Grandmacolypse?

[Assistant]
For eons, humans have been asking questions about our existence. "Who are we? What is our purpose? Where are we going?" And it has been answered.

"Cookies."

No really, cookies. As it happens, the entire universe revolves around cookies. Cookies, you see, are the purest elemental expression of enjoyment and happiness. Just as Ancient alchemists tried to turn lead into gold (Because gold was non-reactive, and was "pure" and "unalterable.") Gold is turned into cookies because cookies are a "higher state of matter." It makes sense that entire worlds, or universes are composed from this higher state of matter.

The reason why the Grandmascolypse happens is because the Grandmas, who normally are the guardian and gatekeeper to all cookiekind, are being shafted by the new cookie producing world. So they respond violently to all mankind.


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

[User]
Has climate change affected weather forecasting?

An increase in severe weather events and anomalies is something scientists attribute to climate change. Does this mean weather in some places is more difficult to predict?

Does climate change make it harder to create accurate weather forecasts? Or is weather forecast technology able to keep up with changing climates?

[Assistant] No. More events are computationally more intensive, but these are not new kinds of weather phenomena. We still rely on satellite imagery, radars (water in clouds is reflective), ground and sea based sensors. We can actually predict a lot more than just a decade ago. Including insect migration, pollen and dust count, movement of smog (and its effects on temperatures). The forecast you see on TV is only a fraction of forecast companies' product. Some companies buy extremely specific products (likelyhood of rail tracks freezing, air quality and humidity around a race track to set up cars correctly, etc) and this was all enabled by access to bigger better faster computers.


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

[User] Can Galaxies "Die" and What Might it Look Like?

[Assistant]
We do refer to galaxies as "dead" if star formation has pretty much stopped. Elliptical galaxies have very little dust in them with which to form new stars, so all the hot, blue, young stars have generally already died off, leaving the cooler, low mass, long lived red stars. We tend to refer to such galaxies as "red and dead". The stars will slowly die, the more massive ones first, leaving the galaxy fainter and fainter. The lowest mass stars survive quite a long time, though, much longer than the universe has existed, so there are no galaxies where *all* the stars have gone out, just the high mass end of the scale.

It's not entirely understood how the gas and dust is removed from these elliptical galaxies. The general thought is that some event creates a lot of radiation which blows the gas and dust away, in a process generally referred to as feedback. One possible cause of feedback is that "red and dead" galaxies may form after an episode of  intense star formation (starburst galaxies), possibly after a merger of two galaxies into one. The high amount of UV light from the numerous forming high mass stars blows the gas and dust out, shutting off any further star formation. Another possibility is that the rapid accretion of material onto a supermassive blackhole in the center (an Active Galactic Nucleus, or AGN) generates such intense radiation that it blows the gas and dust out. Whether AGN feedback or star formation feedback is responsible for the transition from star forming galaxies in the earlier universe to more "red and dead" galaxies in the present epoch is uncertain.


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

[User]
[kaiju movies] why are the militaries so stupid?

Whether it be bombing their own city, wasting time building giant mechs, or giving a nuke to creatures that feed off radiation, the military messes up a lot in these movies. Why?

Bonus points if you can figure out the three movies Im referencing.

[Assistant]
Modern militaries are extremely intelligent and make decisions based off of real-world facts that they've carefully gathered and tested over the course of decades or centuries.  Faced with a single giant creature the answer is obvious: overwhelming and direct force to stop it as quickly as possible.  A single downtown core can be sacrificed if it means protecting the larger metro area and wider economy.

* The first step is always small arms and tank rounds.  HEAT and depleted uranium penetration rounds should cause massive damage to anything living. Period.  Military generals not only *know* that, but base all of their core decisions off it.
* Ground penetration bombs and directed munitions can level an entire city block if necessary, and are the next obvious escalation of power.
* Given that those don't work, you now need something big enough to mount something more powerful but still mobile enough to quickly engage the enemy (which is where mechs come in)
* Finally, nukes are horrifically devastating.  Especially the modern ones.  Launching one at an enemy is a last desperate act to make sure NOTHING survives at ground zero.  Every test that modern military generals have seen says that a modern nuke will destroy whatever it needs to.

Sadly, what military leadership doesn't understand and refuses to grasp (rightfully so, given how they got into their chair in the first place) is that Kaiju **don't follow laws of physics**.  If you put a sack of flesh, muscle, and bone the size of a Kaiju leg in a testing field it couldn't stand up on it's own, let alone protect against directed fire of an M1 Abrams division.  The fact that it can is baffling, and leads to more and more desperate plays that ignore moment-to-moment learning that they might gain from individual engagements.

If the stories track long enough, the military either collapses from these failures, or learns how to fight asymmetrically against the physics-defying might of a kaiju.  It just takes them a while to abandon the beliefs that got them to where they are now.


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

[User]
[Futurama] If mutants aren't allowed on the surface, why does no one seem to mind that there's a girl in the orphanarium with an ear growing out of her forehead?

In *Cyber House Rules*, Bender adopts (and then tries to pawn) a dozen orphans, one of whom has a third ear growing from her forehead. How is this allowable, if it's illegal for mutants to be on the surface?

Leela got a pass because it was assumed she was a humanoid alien, but that doesn't seem to be the case here.

So what's the deal?

[Assistant]
The guy running the place gets money for every child he has, so he just doesn't write that part down. And she's still cute enough not to gross people out more than it induces "poor kid" feeings.

When she turns adult and ugly and unprofitable they'll ostracize her and she'll crawl into the sewer where she belongs.

It's the circle of life.


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

[User] eli5: Why do small jet aircraft, like regional jets and private jets, have engines on the rear, but larger jet planes have engines on the wings?

[Assistant]
Typically, the wings on a smaller plane are closer to the ground.  The plane isn't as thick and long thin landing gear are too easy to break or too heavy to lift.

There isn't enough space under the wing for the engine, and safe clearance against the runway.  Mounting them to the body works as well, and the longer fuel pipes don't add much weight.


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

[User] ELI5 Why is radiation visible on cameras? like a radioactive object would have loads of white dots around it?

[Assistant] Cameras operate either by having pixels on something like a CCD, or grains of light-sensitive chemicals embedded in a film. In both situations the actual radiation, charged particles or high energy rays, interact with small areas of the film or pixels of the CCD. The radiation triggers them as if a large amount of light struck them, producing white spots on that one frame. As many frames of a video affected by radiation are played these spots are visible as very brief speckles.


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

[User]
[ATLA] Was Uncle Iroh trying to hit Aang and knock him out of the sky when Aang first escaped the Fire Navy ship at the Southern Water Tribe?

In the second episode "The Avatar Returns," Zuko yells out "Shoot them down!" and both Zuko and Iroh shoot fire that would have knocked Appa out of the sky if Aang hadn't airbended the fire away. This very likely would have severely injured or killed the Avatar but Iroh was part of the White Lotus whose mission is to help the Avatar.

[Assistant]
Iroh was pulling his punches most of the time against aang, but its very likely he wouldve helped Zuko capture the avatar to regain his honor, and then figure out a way to free him afterwards. Its a fairly logical gambit, and if aang was in a fire nation prison, that would actually make it easier for him and his white lotus buddies to rescue him, as opposed to the kid galavanting around the world.

Now in that exact instance, Its likely he WAS trying to shoot him down, but he probably wasnt trying too hard. The longer the chase went on, the more time he had to change zuko. If they caught aang too soon, zuko would just go back to being the miserable person he was.


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

[User]
If a baby is born premature 7 months in the pregnancy after a month is it going to be more or less developed than if it was still in the womb?

Is it going to be bigger, in terms of body weight and rate of growth? Is it going to be stronger?  Will its cognitive development start as if it was born after a complete pregnancy or no? Basically after a month will it be able to react to stimuli as a baby that did 9 months in the womb and then a month out or will it  behave as a baby born at 8 months?

[Assistant] Premature babies do tend to be delayed in their development. The earlier the baby is born, the higher the likelihood of developmental delays. Most kids catch up by the time they turn two, some even earlier. Depends on if there were any other adverse factors.


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

[User]
ELI5: What is the science behind overclocking a CPU?

What actually happens behind the scenes, inside the computer for it to overclock?

Edit: Went to sleep and came back to crap ton of answers. I appreciate it truly and will read each one. Thanks!

[Assistant]
Imagine 500 workers in your company.

Each worker fills out a form, their work. You give them 10 minutes for one form, since some guy has calculated that to be the best "base clock speed" of 3000 forms per hour.

You actually sell your company to other people and they perform as advertised, but every company you sell has DIFFERENT workers (obviously).

It is still kind of the same company though.

It turns out, your workers fill out the form in 8 minutes on average and then meet in the hallway to chat.

One of your customers thinks he can 'overclock' his company: he tells all the workers they only have 9 minutes to fill out the form.

Works great, there were still resources left in that company and now you have a company that gives 3300 forms per hour (10% increase).

One of the customers friends got wind of the overclocking and tries it with his company. It's horrible: the workers take 9 minutes on average to fill out a form, so on average they should meet the 9 minute requirement, but they have no more time to chat, get depression and burnout. Eventually a worker quits because he had enough.

This is where your company becomes unstable and locks up, e.g. the overclocking went too far, not enough untapped resources were available, mistakes are made that cannot be undone, etc.

The 'potential' for overclocking is different for each model and even differs with each CPU sold.

If you increase the clock speed, some signals can get lost in transit if the physical layout of your CPU is 'bad' (this means that one of the circuit paths during the lithography process was less than ideal, too thick or too thin for example) so you also need to increase voltage, but THAT in turn increases temperature and also, since each circuit path is an antenna, the influence one circuit path can have on another. This can go to a point where to circuits cancel out each other's signals when they 'transmit radio signals' too much. That 'interference' is what cannot be overcome by any means other than designing the CPU differently.

In essence, there's potential to do stuff faster. How MUCH is determined by the quality if the design AND the individual 'print' of your CPU.

To get your CPU to a stable processing speed that is higher than what the manufacturer intended is tricky but can usually be done reliably without damaging the component by

1. increasing the frequency until failure
2. increase voltage to strengthen signal
3. repeat 1+2 until failure because of interference

The reason a manufacturer picks a certain clock speed is simple: yield.

One printed wafer gives a certain percentage of functional dies (the heart of your CPU). Each die is tested to run at the base clock  speed. The better the design and the better the manufacturing process as well as how carefully chosen the clock speed is: more dies per wafer = more cash.

The idea is to get the best die per wafer that can reliably be produced with as few losses as possible.


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

[User]
I don't believe a universal basic income could work. Please CMV.

From a moral standpoint, I really like the idea of a universal basic income, but I don't see how it could work without causing an inflationary spiral. If everyone had a basic income, they wouldn't have to work to survive, which means you would have to pay them more to get them to do something they don't want to do. In addition, paying for a basic income would require some fairly major taxes of some form or another. This is going to drive up the price of labor, which will also drive up the price of goods, which means that suddenly your old basic income isn't enough to live on anymore.

I'm aware that basic incomes have been successfully tried on a small scale before, but a small scale isn't going to lead to an inflationary spiral. Can someone explain to me how this could work on a national scale?

[Assistant]
Are you in the US?

Assuming you are, consider that between welfare, SNAP, the earned income credit and the various state programs, we already have a basic income - it's just extremely complex and split between many different agencies.

If we were to enact a basic income, it would not necessarily involve spending or taxing much more than we do already. The main difference would be that people would no longer have to debase and humiliate themselves with all the bogus requirements we've attached to all the current programs.

As to people not working - the main thing is to ensure there are no income traps, which is much easier with a basic income program. You just have the income supplement roll off by, let's say, $0.75 per $1 of earned income.

This would be better than the current system, where people can get into a situation where taking a job reduces their living standard (particularly at the point where they cease to qualify for Medicaid).


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

[User]
ELI5 : Even with a strong battery why do cars have a hard time starting in cold weather?

I don't understand what is different that prevents cars from starting right up in cold weather. Fuel is present, air is there..spark plugs are ...sparking ..and as long as you have a strong battery the starter is turning the engine...why the struggle?

[Assistant]
Batteries are powered by chemical reactions that make an electric current as a product.  Most chemical reactions occur much slower in cold temperatures.  Slower reaction = less electricity generated per second.  Less electricity per second means your car can't make enough sparks to ignite the fuel in your engine, which means it can't start.

If you have a strong battery, these effects are small, unless you're in like, *really, really* cold weather.

**Edit:** Another user pointed out that sparkplugs don't actually carry the current to the engine to make it start.  That's done by a separate motor carrying an inrush current.  It's still an issue with current, just not with sparkplugs

**Edit 2:** Those claiming that engines won't start at low temps because of oil being more viscous or that moving solids are packed closer together and introduce friction as a result aren't *completely* wrong, but it's not the primary reason for this occurrence.  The density of a liquid or solid (such as motor oil or the metals used in your engine) does change with temperature, but the scale at which this occurs is not enough to prevent your engine from starting (at least for the majority of cars on the road).  It is enough, however, to increase the amount of work required by your engine to do its job, which would increase the current needed to start your engine. You'll also have lower gas mileage when your engine is cold vs warm for the same reason.


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

[User]
[WH40] What is the daily life of a "middle class" Imperial Citizen?

My lord, ever jealous of the popularity of Kallendine's 'Benefits of Tyranny', wishes to publish a rebuttal. However, lofty as his spire is, he has never really encountered the common people outside youthful sport hunting dregs, and has blessed me with the task of understanding the lives of your average imperial citizen of status higher than the serfs of Sepherus Secundus. I know that those who labour in the neverending grind for planetary stability tend to have very strict work schedules, but what is it really like for your common fellow to wake up in a new day in an Imperial world, to when he or she returns to slumber for the next, and, if you'd like to be remembered by me after I achieve the elevating approval of my lord, how does this compare to your unfortunate serf, who seem to often be limited to strictly eternal toil with required rest spotted about?

[Assistant]
The Imperial Citizen who may be said to occupy the middle class will generally fall into one of three categories, criminals and heretics whose ill-gotten lifestyles are unworthy of consideration by your lord notwithstanding.

1.  Minor officials belonging to dominant agencies on their home planets depend upon a higher complement of resources than manual laborers or semiskilled workers.  In order to properly complete their functions within the Imperium's great administration, they require superior food and accommodations, as well as occasional intellectual and spiritual enrichment, distinct from irresponsible and oft heretical diversions, beyond the working norm.  Of course, as with all true the servants of the Emperor, they receive and ask for no more than is absolutely necessary to perform their roles.  Those worthy of further resources shall receive them, for the Imperium of Man is a just and good warden of humanity.  Private rooms, varied meal composition and the odd amasec are broad features of life in this social category.

2.  Servants of the nobility and high administration enjoy a middle-class lifestyle in their own right, though commonly further improved by the surroundings in which they work.  They are paid from the fruits of righteous service earned by their masters, and it remains the sovereign and essential right of the Imperium's most materially empowered citizens to attract the devotion of the finest advisers and agents.  Such employees, as you prove so well by your loyal execution of your master's wishes, are again granted the lifestyle necessary for their function in service to the glorious Imperium.

3.  Those who work independently of the great governing agencies of the Imperium or the domestic power class may still enjoy a middle-income lifestyle by providing valued services to other citizens; their life consists of small-category trade and sales as well as the same pious habits demanded of all blessed to live in the Emperor's realm.  Prayer and enjoyment complement the brutal necessities of work.

Conclusion:  The existence of a middle class citizen of the Imperium is a worthy and fruitful one, essential to the survival of civilization and concomitantly rewarded with carefully sanctioned and judiciously distributed luxuries.  The triumph of tyranny is in allocating resources to the profit of humanity, but a kinder hand may achieve just as much and more.

TL:DR  Relative to serfs, more free time, more variety, more comfort.  Still cogs in the great Imperial machine, but better oiled.


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

[User]
ELI5: If the U.S. president is commander of the military, why isn't his/her experience in military tactics and strategy ever a talking point?

It seems like people would want to know how effectively a presidential candidate could command the most powerful army in the world instead of how he felt about abortion and gay marriage.

[Assistant]
Because we don't expect the President to be an expert in military tactics any more than we expect him to be an expert in medicine or prison construction or chemistry or meteorology or agricultural science or any of the other things that the President is ultimately responsible for,

What we need out of our leaders is leadership -- not nerd-like knowledge of a narrow area of focus. We need someone who can get and listen to people who *are* experts in these areas and make the appropriate decisions.


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

[User]
[The Purge]What makes theft and arson unpopular choices during the purge?

Of all of the Purge choices. Murder and assault was the choice of things to do during the purge. Only a small portion of people participating would go steal from others.

What makes purge night even less popular than Black Friday as a way to get free stuff?

[Assistant]
Murder is legal. That means killing in self-defense is too. I'd imagine that a dozen or so people on the roof of a Walmart would dissuade robbers in short order, and people clearly invest quite a bit of money personal defense. An honest thief wants to avoid confrontation, so knowing that an attempted burglary could end with a face full of buckshot, going out on Purge day would probably be undesirable.

Another thing to consider- the people most likely to steal are also the worst equipped to steal from people actively protecting themselves. Upper and middle class homes will be too well defended for a common burglar, which means stealing from poor homes, which circles back to the shotgun situation.

On top of all that, a thief would still have to make it to safety during the madness. Someone with a sack of loot on their back is going to be a big target for other rioters.


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

[User] ELI5: What is (or was) the point of wisdom teeth?

[Assistant]
Anthropologists believe wisdom teeth, or the third set of molars, were the evolutionary answer to our ancestors early diet of coarse, rough food  like leaves, roots, nuts and meats  which required more chewing power and resulted in excessive wear of the teeth.

The modern diet with its softer foods, along with marvels of modern technologies such as forks, spoons and knives, has made the need for wisdom teeth nonexistent. As a result, evolutionary biologists now classify wisdom teeth as vestigial organs, or body parts that have become functionless due to evolution.

They are typically removed because human jaws have become smaller throughout evolutionary history, when wisdom teeth form they often become impacted, or blocked, by the other teeth around them.


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

[User]
[Star Wars] Why did Darth Vader give up on overthrowing the Emperor and ruling the galaxy as Father and Son?

In Episode 5 he makes it clear that this has been his goal for a while, the current expanded universe also shows that pre-episode 5 he learns the identity of the rebel pilot, and starts to put his plans in motion.

However many months of planing leads up to Darth Vader offering Luke a chance to "Rule the galaxy as Father and Son".

The next time we see Vader, he is sub-servant to the Emperor once more, "You don't know the power of the dark side. I must obey my master." and later "It is too late for me, son. The Emperor will show you the true nature of the Force. He is your master now."

I get that Vader didn't wish to leave the Dark Side (until the very end), and Luke didn't wish to leave the Light Side. But Vader abandons all ideas of overthrowing the Emperor, just accepting that he will be treated as a disposable asset if the Emperor does turn Luke.

Why is this?

[Assistant] Luke wasn't committed to the idea. Vader isn't going to go out on a limb and try to overthrow the Emperor with him right there. Vader isn't powerful enough to take on Palpatine alone. He *needs* Luke to fight with him.


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

[User]
[Star Wars] Before the prequels, what was the Extended Universe story of how Anakin became Darth Vader ?

Before the prequels, there was books, comics and other Extended Universe stories. What was the story of Anakin before Phantom Menace came out in 1999? Was it the same, or did Lucas change key points in the story?

[Assistant]
It was largely the same as what is known now.  Anakin Skywalker turned to evil, and dueled his former master Obi-Wan Kenobi.  Kenobi won the duel by dropping Anakin into a vat of some hot substance (some say it was molten metal, others say it was lava).  Anakin's resulting injuries led to him being put in the suit, and becoming the Darth Vader that terrorized the galaxy for decades afterwards.

The specific details were not known back then.  So, for example, there was nothing on Order 66, the name of the planet where the duel occurred was not known, there was no Trade Federation or General Grievous, and there certainly wasn't a Padme who died in childbirth.  Furthermore, while it was known that something called the "Clone Wars" had taken place, no one knew the specifics of the war, such as the combatants on either side.


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

[User]
[Men in Black 3, spoilers] How is J in MIB?

K recruited J into MIB.. In the alternate timeline where K is dead, how is J in MIB? Who recruited him?

In the alternate timeline, J's father was probably alive, or at the very least K would have died before he met J, so no one at MIB would have known about him. Even if his father was dead in both timelines, he would have just been some kid.

[Assistant] Given how he was discovered, in that he chased down a fugitive alien on foot and how that doing so with that species was conventionally seen as 'impossible', and there was already an agent in pursuit of the fugitive, whatever other agent had been sent would have taken the place of Kay and recruited Jay.


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

[User] [Star Trek] Do Captains have other areas of expertise like flying or engineering or did they spend all of their time at the academy just learning how to "Captain"?

[Assistant] The Command track involves learning enough of more or less everything to be able to fill in without spending the time necessary to specialize. The extra time is instead spent on "captaining" - that is, tactics, leadership skills, history, and so on.


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

[User] ELI5 - why do antidepressants make it more difficult to reach orgasm for some?

[Assistant] Antidepressants affect how nerves send signals to each other. An orgasm occurs when nerves linked to the genitals send signals to the brain that the brain interprets as pleasureable, with sufficient strength and over a sufficient period of time for the brain to figure that sex is well under way and now would be a good time to finish up. The exact arrangement of communications here is very complicated, but the basic gist is that antidepressants, which affect how nerves communicate, makes it harder for this system to reach the brain's predetermined level of sufficient stimulation.


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

[User]
If supply problems are causing inflation, isn't increasing interest rates make that worst?

From what I understand the supply problem caused by the pandemic led us to inflation and the war exacerbated it.

If that's the case, isn't raising the interest rates make that problem worst? By making difficult to businesses to adjust (aka invest) to the demand. At the same time, destroying the economy.

A secondary question is, what can governments do to inscrease supply?

Maybe nothing? That's why the only alternative is lower demand?

[Assistant]
Increasing interest rates should lower demand and ease backlog/congestion on the supply-side in theory.

Increasing supply from a government's perspective would involve investing in building programs, infrastructure, and liberalizing the labor market to some extent.


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

[User]
(Star Wars) How did the Death Star move around the Galaxy

Did the whole station have a hyper-drive or something?  How did something that large get from place to place?

[Assistant]
The DS-1 had 123 Hyperdrive generators spread throughout its superstructure. Each one of them would have been capable of moving an entire capital ship through hyperspace with ease, and all of them together could create a hyperspace tunnel large enough for the battle station to go through. It had to take things relatively slow, though - it was classed at 4.0 past lightspeed, meaning it could only go at 1/8th the speed of a fast ship like the Falcon and half the speed of the other large ships in the Imperial fleet, like the *Executor*.

Once it was in a system, the Death Star generally relied on orbital mechanics to get around. While it possessed sublight engines, these were really only useful for orbital adjustments. (Incidentally, that's why it had to wait around in orbit before it could get a clear shot at the Rebel base during the battle of Yavin).

The Death Star II, had it been completed, would have been more maneuverable than its predecessor in both respects despite its greatly increased size. Its hyperdrive rating was set to be 3.0, and it was also meant to have massive ion engine drives to allow it to change orbits more efficiently. However, neither of these systems was operational by the time of its destruction at the Battle of Endor.


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

[User] If sodium nitrate is known to cause DNA damage then why does everyone think it's OK for it to be used as a preservative in all our meat products?Are there not alternative preservatives?

[Assistant] It's a risk/reward scenario. Nitrates can potentially increase the risk of cancer - the degree to which the risk increases is not firmly known. However, nitrates are *incredibly* effective at inhibiting pathogen growth in high-pH foods like meat, especially considering their cost and ease of use. Much like sulfites, which can cause allergic reactions (in some cases fatal ones) in asthmatics yet are still used in winemaking and dried fruit, nitrates are still sitting on the 'useful' side of a risk/reward assessment. It's possible that that will change once we have a clearer picture of the risks.


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

[User]
ELI5: What exactly happens when I click on "Safely Eject" for a USB or external hard drive?

.

[Assistant]
When you save a file to disk or to a USB stick, it usually is not written completely at the moment of saving. Writing to disk means that your file is written to a part of your computer's memory, after which the operating system tells your program the file has been saved. In the background, the data of your file is then transferred from this *memory buffer* to the storage medium (that is: your disk or USB stick).

So after you have saved a file, parts of it remain in memory and have not yet been written out to the storage medium. However, your program has told *you* that the file was successfully stored.

When you prepare a USB stick or external hard disk for ejection, you tell your computer to finish writing out all data that is currently lingering in the memory buffer, while at the same time rejecting any new files to be written to the device.

After the buffer has been *flushed* (that is what it's called) all parts of all your file(s) are actually stored on the hard disk or USB stick and it is safe to disconnect it from your computer.

The real-life situation is a bit more complicated, because in addition to writing the file's content to the storage medium, it also takes some housekeeping reads and writes to register *where* exactly your data was stored in the file system of the external drive or USB stick.

tl;dr : pending data needs to be written out to the storage medium from the memory buffer.

Edit: removed some *actually*s and polished up lightly.


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

[User]
[Avatar: LOK] Why did Unaloq bother occupying the southern water tribe?

It seems to me like his plans would have gone off without a hitch if he'd just left the southern tribe alone, Korra would never have suspected anything and would have opened the northern gate for him. Would the two tribes being united make any difference once he ushers in 10,000 years of darkness?

[Assistant]
Unaloq seemed, at times, to believe he was going to become something analogous to the light Avatar, a human person in full control of his senses and simply backed up by the spirit of dark and chaos fused into his soul.  The plan was not (just) to become a gigantic monster and fire lasers at Republic City, he wanted mankind to survive and be enslaved under his rule.

To that end, conquering the southern water tribe was just getting a head start on his conquest of the entire world.


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

[User] ELI5: Stocks are down worldwide (apparently as bad as the 2008 financial crisis). What does this mean for your average Joe?

[Assistant]
Unless your "average Joe" is investing actively... probably not much.

It's a bloodbath on the market today... but this has all the making off an overreaction/panic (the market has dropped 1500 points in 25 hours of trading.... and the world isn't currently being attacked by aliens) so things will likely stabilize out and recover in the coming weeks.


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

[User]
ELI5: Object Oriented Design

Hi.

I am currently studying computer science at university. I am a first year in need of some help.

Please could someone explain to me the main principles behind Object Oriented Design. I am finding some of the concepts hard to get my head round.

Thanks in advance!

**EDIT 18:04: Thanks for the answers. If any of you could explain the concepts of interface and polymorphism then that would be excellent.**

[Assistant]
It's helpful to contrast with other design philosophy. If you want to accomplish a task (especially large ones) there are many different ways of doing it.

In procedural programming, you would just make a list of all the things that need to happen, and then just do them in order. This can be a mess for a larger project.

Object oriented design is more structured and abstract. Typically, you break ideas up into 'objects', and then define how objects interact with each other.

For example, say you're making a video game which has bad guys that can shoot at you. You could define a 'class', which is a template for objects.

    class BadGuy:
        def __init__(self, damage, health):
          self.weapon_damage = damage
          self.health = health

        def attack(self, other):
          other.health -= self.weapon_damage

        def get_attacked(self, other):
          self.health -= other.weapon_damage
          if self.health <= 0:
            self.die()

        def die(self):
          ...

This helps to organize code immensely. Since objects share so many traits (health, damage, etc.), this lets you write the base object that can be extended and specialized from there. The __init__ function creates an object (referred to as self). For example:

    badguy1 = BadGuy(damage = 5, health = 10)
    boss = BadGuy(damage = 40, health = 120)
    badguy1.attack(boss)