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

[User] ELI5:Why do new albums on iTunes cost the same as the hard copy in the shop when you're getting less for your money and there aren't any shipping costs involved etc?

[Assistant]
The answer to "why does X cost $Y" is almost always because that's what people are willing to pay you for it.

As a business, what it costs you to sell the product (CoGS) is just a starting point. You poll your typical customer, construct strategy models, compare test results, etc...

Then you price your good at whatever price point you think is going to maximize profits.


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

[User]
[General SciFi] Why aren't more spaceships spherical?

I'm a software engineer collaborating with a team of physicists and other programmers to develop functions to assist in making physical calculations for spacecraft with odd geometry. I don't have to do this, of course, since food and energy are free, but I've chosen to help develop flight software as community service and for personal development.

What bothers me, though, is that this work needs to be done. All my physicist friends tell me the calculations are much easier if you assume the object to be frictionless and spherical, and I know enough about asteroid mining to say that getting the material for round ships isn't that hard. So why the weird shapes?

[Assistant]
Reentry. Unless they stay permanently in space, they will be entering and leaving atmospheres regularly, and that means aerodynamics matter.

Heat. The more power a ship consumes, the more heat is generated. A sphere is optimal for a low-power craft to retain heat, but very inefficient for a high-power vessel generating lots of waste heat and needing to radiate it away.


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

[User] ELI5: Why do some materials feel wet when actually they are just cold.

[Assistant]
> Why do some materials feel wet when actually they are just cold.

We don't have "wetness sensors" on our skin. We can detect pressure and changes in temperature. Typically speaking water is difficult to change in temperature and a good conductor of heat so it feels cold. But things like metal can also be good conductors of heat and without texture cues to determine the difference it can be confusing if something is wet or just cold.


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

[User]
[Marvel] Were any beings strong enough to resist the Gauntlets snap?

Just wondering if there were beings who could resist being erased by the infinity stones like The Living Tribunal or similar?

[Assistant]
Yes, the Living Tribunal is beyond the power of the infinity gauntlet. He proved so when Adam Warlock was brought before him in possession of the infinity gauntlet. Warlock got angry and erased all the abstract entities in attendance except for the Tribunal, who brought back the abstracts immediately with a thought.

Pre-Retcon Beyonder would also certainly be stronger than the infinity gauntlet.


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

[User]
[Neo Genesis Evangelion] What happened to Shinji and Asuka after the Third Impact?

I know Shinji and Asuka were the two people left after the whole Third Impact, but I wanna what exactly happened. Were they just left there? I am also not sure if Asuka died or not after Shinji decided to kinda, choke her for some reason, and they show presented showed her as still alive, I think? I am not sure, I know about the rebuild series and the time loop thing though, but I am not sure if the time loop happened immediately after or after a long time after. Is there even a specific time loop that occurred after the first? I am trying to figure this out still and it's a little confusing, so an explanation would help.

(I put this as a spoiler because since Netflix put the show up on their website and now people are watching it. People might get into the series and other stuff that way so yeah, I don't wanna spoil it for newcomers.)

[Assistant]
They were the first two, they might not be the only two. Anyone who can self-actualizes and choose to live despite the possibility of pain could come back if they want to.

Now they have to learn how to live with each other, knowing that they can hurt or comfort each other.

The time loop thing is a theory, not yet explicitly confirmed.

The manga shows a somewhat different end result, which ends up with the world mostly having been recreated as it was before the Angels, except that Gendo and Rei are still gone, and shows Shinji and Asuka meeting again for the first time with no memory of each other.


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

[User] ELI5: When I feel pain from a burn I feel the instant pain then a brief period before throbbing pain starts, are there two different pain receptors?

[Assistant] When you burn yourself, an immediate reflex occurs to make you pull your hand back. This isn't pain, and it isn't even processed by the brain, but directly by the brain stem. When that reflex is occuring, you haven't had enough time for the pain signals to be transmitted and processed by the brain yet. When those signals get there shortly after, your brain processes them and then creates a pain response localized to that area, essentially telling your hand "Hey, hand! You should be hurting right now!" Your obedient hand then says "Ok! I'll keep you updated on how much this hurts too!" And then your hand hurts like a bitch.


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

[User]
Why do shaving cuts bleed for so long? (i.e. why doesn't the blood clot normally?)

When I get normal cuts, the bleeding usually stops in a few moments depending on the damage. Smaller cuts stop bleeding faster, larger ones need a bandaid to help.

But when I slice myself with a razor while shaving, it seems to bleed for nearly an hour before finally clotting. No matter if I use a bandaid, piece of paper towel, etc.

Why is that? And what can I do to speed up the process?

[Assistant] Layman: Until someone with more knowledge chimes in, I'll just say that the face has more blood vessels per area than any other part of the body (except maybe the genitals). Also razor wounds are not jagged, they are narrow and sharp, so there is less skin "teeth", for lack of a better term, for the clot to adhere to.


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

[User] ELI5, why does compressed air get colder as you use it?

[Assistant]
> why does compressed air get colder as you use it?

Probably what you are familiar with is "canned air" such as in computer cleaners. They aren't really compressed air but rather a chemical with a low boiling point and low vapor pressure. This allows them to pack a high volume of gas into a container without it needing to be exceedingly strong.

When you release some of the gas out of the container the liquid within will start to boil in order to restore the vapor pressure within the container. The change in state from liquid to gas requires energy which is absorbed in the form of heat, cooling the walls of the container.


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

[User]
Why do high temperatures damage hardware, specifically cpu's and gpu's?

I've searched everywhere and haven't been able to find a straight answer as to why heat will make processors fail.

Specifically temperatures >100C.

What is actually happening on a microscopic and macroscopic level that is causing damage?

[Assistant]
At the microscopic level, a CPU consists of hundreds of millions of transistors. A transistor is, at the most fundamental level, multiple layers of semiconductor material with different types of impurities. The transistors are only a few nanometers across, so the impurity atoms don't have to move far to render it useless, and higher temperatures aid atomic diffusion. The stress, caused by thermal expansion in a constrained system could also cause atomic-scale defects to form, which would affect its electrical properties.

At a macroscopic level, CPUs are made of several different materials. There's silicon, copper interconnects, dielectric materials like silicon dioxide, and plastic or ceramic packaging. All of them have different thermal expansion coefficients, so parts may begin to crack.


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

[User] ELI5: If games can render near photo-realistic graphics in real-time, why does 3D animation software (e.g Blender) take hours or even days to render simple animations?

[Assistant]
Games use a lot of tricks to fake the photorealism at less cost than doing it for real (compressing textures, popins, etc.). The most important one is the lighting. You may notice that shadows don't always look right in games. You know how when you hold something colored under a light, it starts to glow that color? Games don't do this because they don't simulate the light for real, they change the textures to make shadows and light.

Real animation software takes no shortcuts and renders things with full textures and full detail. This software often calculates the path of each ray of light bouncing around the area until it runs out of steam. This calculation is what takes all the time because there are millions and millions of light rays to trace.

Fun sidenote: a few weeks back, Nvidia managed to make real-time Ray tracing possible using some new technology they're developing, but so far it still take colossal amounts of power to run.


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

[User] ELI5: what's the purpose of electronically signing on a credit purchase especially when most signatures are not the person's actual signature or lazy scribble that doesn't resemble letters and In what ways are they used?

[Assistant]
There is zero security in a signature. No one checks them, and only a very few are able to detect what is a genuine signature and what isn't.

The best they can do is provide evidence if the holder of a card who did a transaction tries to charge it back. Then the recording of the signature can be verified by real experts, or, more importantly, video of them signing for the transaction produced in court to support a fraud charge. Similarly, the record of a fraudulent signature will be an extra fraud charge if they catch someone who uses someone else's card.


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

[User] ELI5: What caused the financial crisis in 2008?

[Assistant]
The United States slipped into a minor recession right after 9/11, so the government used its control over how much money is circulating to make it cheaper to borrow money. Because interest rates were low, people borrowed a lot of money and used much of it to buy houses.
While this was happening, home prices were increasing year after year, and everyone assumed this would continue forever.

But then the government decided the 9/11 recession was over and decided to raise interest rates nationally.
Suddenly people owed creditors more money each month for their home loans, because their personal interest rates were not set in stone and instead were set to fluctuate with national rates.
As the cost of paying creditors back increased, a lot of people all at the same time found themselves without enough money to keep paying for their homes. The creditors responded by taking ownership of these houses with the intention to sell them to someone else.
But all of these homes going up for sale at the same meant that houses were suddenly abundant. With everyone looking to sell newly acquired houses, home prices fell.
For people still paying their mortgages, payment schemes reflected the old, higher home values, so many individuals simply allowed creditors to take possession of their homes rather than pay creditors more than their homes were suddenly worth.

As these houses went up for sale, home prices were driven down even further and created a self-perpetuating cycle.

The continued fall in the home prices affected homeowners and those still committed to paying off their mortgages because the worth of their most valuable asset dropped.
Importantly, the banks that originally arranged the mortgages that so many Americans were unable to pay or had walked away from no longer owned the debt of their one-time customers. They sold the right to people's future interest payments to larger financial institutions that put the mortgages of many, many people together and allowed investors to in effect invest little slices of these huge mortgage bundles. This meant that investors were betting that people would keep paying their mortgages and would earn money so long as that was the case.

When people either couldn't pay their mortgages or decided it was smarter to just stop paying, investors who had bet on these mortgages came to realize their earlier bets were much riskier than many of them had understood and lost a lot of money. This was the collapse of the investment banks and their related insurance organizations.

It wasn't just investment banks who had a stake in these mortgages, though. Many ordinary Americans' savings were to some extent tied up them through stock ownership and where their pensions were invested. As a result, many people became poorer than they had been only a few months before and reacted by spending less.
Now Americans were spending less because their homes were worth less, their stock was worth less, and their savings were worth less. Businesses reacted to decreased interest in buying their products by producing fewer products. Because businesses were earning less revenue, they lowered salaries and fired employees no longer necessary for lower levels of production.

As people across the country adjusted to lower incomes and joblessness, they too cut back on their spending, which compounded the situation and led even more businesses to lower salaries and fire workers.
This brings us to pretty close to where we are now. As a country, we have begun creating more jobs each month than we lose but just barely. And these new jobs pay much less than the old jobs did and are largely temporary as businesses wait to see if Americans' demand for their goods increases to levels that justify permanent hiring.

There's a ton more to the story about exactly why everyone was so sure housing prices would keep rising, where regulatory organizations failed, how banks encouraged reckless lending, and a bunch of other really important stuff, but this is a chain of cause and effect at the center of a lot of the mayhem.


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

[User]
[Lord of the Rings] If elves have such keen senses, why would they need to make weaponry that alerts them to the presence of orcs?

In the films, Sting doesn't give them much lead time before the orcs appear.  They don't seem particularly inclined to be stealthy, in any case, always charging in.

[Assistant]
It might have been used as a component to a strategy of terror - rather than alerting the elves using the weapons, it would alert the orcs that the wielders are elite warriors with fine weaponry, and would likely cause the orcs with less moral to flee rather than engage.

Orcs are cowardly and unwilling to attack without overwhelming force, even at night. If faced with a force of elite elvish warriors with glowing swords, it would be devastating to their morale.

Especially considering the Elves likely ambushed the Orcs repeatedly before facing them in direct battle.


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

[User]
ELI: If humans originated in Africa, how did we also develope on remote islands like Japan?

Did humans travel to japan in boats from china and after a while forget they came from the mainland and created their own origin stories? Or, if not, how did we get to japan?

[Assistant] The former. Humans radiated outward from Africa in several waves, and over time colonized pretty much every place that could support us. Sometimes they ended up in places that later became islands after sea levels rose, and sometimes they used rafts or boats. You can even use genetics to work out roughly how long ago different populations diverged and when they first arrived wherever they ended up.


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

[User] [MCU] What's the hierarchy/order of command in the Avengers?

[Assistant]
There's no real hierarchy.

Fury started it and Stark kept it going through funding. Rogers kept people motivated because he wanted to get rid of Hydra. Ultron happens, authority is imposed and the group basically breaks up.

Civil War shows that there's no leader. People happily abandon Stark. Doesn't matter if he's playing the bills. The group running with Rogers don't call themselves the Avengers. They're fugitives.

After Thanos, Natasha is the one keeping everyone organized. But she's literally running on peanut butter sandwiches.

Fury is right. The Avengers isn't an organization. It's an idea. It's a group of people who sometimes decide to work together to do something.


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

[User] ELI5: Why does your body feel really hot inside or has this weird feeling for like 1 second after you stumbled or maybe even nearly dropped something important? I guess it has something to do with adrenalin but what does really happen?

[Assistant] Yes, it does have to do with adrenaline. Adrenaline is released in your body, which causes your heart to beat faster which brings more oxigen to your cells which causes them to burn that oxigen more intensely increasing metabolism and increasing your body temperature in the process.


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

[User]
[Marvel/DC] Out of the various super-teams, which ones would actually have you concerned from a security standpoint?

Let's say your taking the role of an operative of ARMOR or some similar organization. For those who don't know what ARMOR is, it's an arm of SHIELD that focuses on observing alternate realities.

So out of the following Super-teams, which do you think is the most dangerous in both terms of power and any psych profiles you can gather on said team members:

Justice League (Assuming that it's only made up of the 7 founders)

Avengers (The 6 original founders from the comics plus Captain America.)

X-Men (Only the team members that we see in the 90's cartoon)

Fantastic Four (Only the original four)

The Bat-Family (Includes all the previous Robins and any of the previous Batgirls but NO Batwoman or anyone else)

Edit: The gist of the question is: "Which super-team would be the most likely to go rogue and how dangerous would they be?"

[Assistant]
All of these teams present an end-of-the-world level threat if they went bad, so the one that worries me most is the one that would be hardest to stop.

That is, very easily, the Justice League. Of the original seven, Superman, Martian Manhunter, and Wonder can end the world individually, and all are extremely difficult to damage. Green Lantern isn't quite at their level, but he's close. Flash, if he was using his powers intelligently, is nigh impossible to contend with. Batman, despite being a mortal, has the capability to killing all of them, which puts him at a very high danger level, as well, because if a guy can kill Superman, there isn't a whole lot that will stand in his way. Aquaman is the least dangerous of the seven, but he is the King of seventy percent of the earth.

The Bat-Family is second on this list only because Batman is also part of the Justice League, and if the entire league goes rogue there are no contingencies that will be effective. The Justice League *is* the contingency for Batman going rogue, so there's at least a chance that the Bat is taken down if it's just him and his various Robins.

The X-Men are next on the list. Again you have a number of individuals who could end the world solo; Xavier with Cerebro could mind-flay the planet, and Ice Man could turn the entire world into a 0-degree Kelvin wasteland. You've also got a chick who is prone to becoming the avatar of flaming, psychic destruction, and she's dating a control freak and the least polite Canadian on the planet. However, there are technologies, like Sentinels and anti-mutant manacles, that can slow them down or stop them outright.

The Fantastic Four are the next most dangerous, primarily because of Sue's force fields, which are nearly impenetrable, and Reed's technology, because Reed can ass-pull a planet killer if you give him a tin can, a ball of twine, and twenty minutes. Still, you've got guys like Tony Stark and Victor von Doom who would be able to give them a real problem if things went south.

The Avengers are probably the least dangerous. Thor could kill the earth with his Godblast, but aside from that the most directly dangerous is Hulk, who's a city-buster under most circumstances. The real danger is Tony going bad, but then you're looking at a dictatorship, not an end-of-the-world scenario.


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

[User]
[Futurama] Why is the world so misinformed about the 2000s?

Shouldnt there be enough heads or frozen people to give a good picture of what happened?

[Assistant]
Not that many people talk to the heads in the head museum. As you saw when Fry hid in there, there was barely anyone in there. The heads *also* have become a bit eccentric, and aren't generally treated with much respect. Frankly the only ones with any semblance of respect comparable to what they had in their home era would be Nixon and some select icons. And Nixon is pretty crazy in his own right, so what do you think that does for the image of heads on the whole?

Sure people could trust these heads from the 20th century. But why bother? The information is largely invalid anyway due to the mental breakdown shown by many of the heads as they become quirky (and in Nixon's case, maniacal and insane). As most people don't give a toss about the barbarians of the 20th century anyway, why bother trying to get the proper story of how things work? Especially when Fry (a living specimen of the 20th century) explains what life was like (sometimes incorrectly), and he's not exactly someone 30th century folk would want to know more about. It's like if we revived someone from 1017 and found out they were a peasant who ate shit and slaps donkey testicles for fun. Not prime research material.


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

[User]
[Teenage Mutant Ninja Turtles] What exactly is the Ooze or mutagen?

So what exactly is the ooze or mutagen and why does it turn animals humanoid? Or turn human's into humanoid animals. Where does it come from and how does it work? Can it be undone once mutated?

[Assistant] It depends on the Canon. In some cases the Ooze is extra terrestrual/dimensional and has origins relating to krang and his people in others it is created by humans via unknown methods and has a mixed bag of effects.


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

[User]
How are toll roads legal? I thought that taxes payed for roads?

Question in the title plus a bonus: can you get a ticket for using the fast pass or pike pass lane without having the pass?

[Assistant]
You pay a premium on certain frequently used roads/bridges/tunnels in order to supplement the general taxes.  This keeps people who use the road more (though not entirely) financially responsible for contributing to upkeep.  As opposed to raising taxes on everyone all the time.

LY5?

Every person in your neighborhood has access to dial-up Internet because they live there.  If people want faster Internet, they can pay a "boost fee" for a speed boost.  This speed boost makes things faster, but maintenance on the boosters costs a lot of money.  The internet company uses the "boost fee" to make the boost lines all better without making everyone in the neighborhoods pay for all the repairs.


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

[User]
[Super Heroes] Okay, lets put this to bed: which Superheroes DO go down on their partners?

Assuming that Batman doesnt (which I dont personally believe but whatever) and Green Arrow does, who else is eating that pie in bed?

[Assistant]
Not only does **Daredevil** go down, his ability to sense the heart rate and internal physiology of his partners means that he plays them like a fiddle. And he only gets better each time.

**Cyclops** probably does not. Since his eyebeams can punch holes in mountains, its too much of a risk.


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

[User]
CMV: The free market isn't going to save the planet

Let's be real, all these "green" products and no straws/plastics bags are just for show, they don't do anything meaningful against climate change.

We are too far gone to expect the free market to come up with solutions that we needed to implement decades ago. And that's assuming corporations even want to solve it at all, most seem on the path of make money and screw the planet.

Right now our best chance is massive government intervention, something like a ww2 homefront situation where rationing and other measures are taken. For example, this could help reducing the massive demand on meat that drives deforestation, water pollution and many other problems. Same with air travel for tourism.

Governments during ww2 didn't give a crap if you couldn't eat whatever you wanted all year long or travel long distances to visit relatives.

Their answer was "we are on a crisis so deal with it", that's what we need right now.

[Assistant]
The free market optimizes within the constraints set by the government.

If the government isnt creating the right incentive structure, yeah - were gonna have a problem.

But the free market is still a powerful force even if government isnt optimal.  The tipping point to a greener technology becoming cheaper creates a lot of good - and were seeing that with green energy and batteries, as well as artificial meat and more efficient lab farming.


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

[User]
[The Matrix] How did the first person hack out of the Matrix?

In the movie, we see people pulled out of the matrix by people who are already outside of it. How could you get out if there were no one to pull you out?

[Assistant]
>"When the Matrix was first built, there was a man born inside who had the ability to change whatever he wanted, to remake the Matrix as he saw fit. It was he who freed the first ofus, taught us the truth - As long as the Matrix exists, the human race will never be free. After he died, the Oracle prophesied his return and his coming would hail the destruction of the Matrix, end the war, bring freedom to our people. That is why there are those who have spent our entire lives searching the Matrix looking for him.".

-Morpheus to Neo.


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

[User]
[DC] I have done nothing with my life but train to lift heavy objects. Am I stronger than someone like Batman or Bane?

Okay, so I have spent every moment of my life training to give myself the absolute max of human strength. If I wanted to I could easily get to the olympics and bring home gold for my country. Every waking hour of my life has been spent weight lifting, bulking up, or lifting more weights.

I should be stronger than either Bane or Batman, right? Batman and Bane have to spend hours upon hours doing things that aren't getting stronger. They have to get book smarts, they have to prepare for plans, Bruce has to keep up public appearances every so often, do some detective work, heal wounds that he gets during battle, Bane has to spend time in prison, get more venom, etc.

So will me spending my entire life for strength make me physically stronger than these people?

I'm not asking if I could beat them in a fight, only if I'm stronger than them.

[Assistant] Probably,  though it's worth noting that they have really good genes and you may not. Also note that you would be better at the lifts you practiced, but not a better fighter. Also weaker then Bane when hes on venom.


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

[User] ELI5: What is the difference between carbs and sugars if carbs are broken down into sugars? Also why are sugars so much worse than carbs for the gut microbiome if they end up as the same thing?

[Assistant]
If you think of your metabolism as like a campfire, then carbs are wood.

Sugars are twigs and leaves. You can just pick em up and start a fire with them. Glucose is one of the simplest sugars. This is basically leaves. Sucrose might be like twigs, since it's a little more complicated and takes a bit of work to get burning.

Starches are like small logs. It's difficult to start a fire with just chunks of wood, but doable. You gotta put more work into it. However, they burn for longer. You can't create a useful campfire with just twigs and leaves, so if you only eat those, you're gonna struggle in the long term.

Fibre is like trees and big logs. You straight up can't make a campfire with these, they're too big. But you can break them up into small logs, twigs, and leaves, and use those. Generally, you can't do this by hand, though, you need a tool: an axe. And some trees are so tough that they're just not worth the bother. They form an important part of the ecosystem though.

We can't directly digest fibre and some complex starches, but many bacteria in our gut act like axes for us, and break down the fibre and starches. Other fibre is just too complex and we don't digest at all. But it's important to our digestive system because it helps flush stuff along.


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

[User] [The Expanse]how long can the ships create linier gravity through acceleration before they max out on speed and have to stop and start again?

[Assistant]
...there is no max speed other than the speed of light.

The fastest, although least fuel efficient, way to travel in space is max burn for half the distance then flip over and max burn for the other half.


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

[User]
[Star Wars] Should the Naboo have been suspicious when the Gungans put together a well organised and equipped land army in an afternoon? Who exactly were the Gungans planning to fight before the Trade Federation showed up?

So in the Phantom Menace, after a little encouragement Boss Nass, calls his banners and immediately has a large well organised and equipped land army at his disposal. They are armed with shields and weapons capable of putting up at least some fight against the Trade Federation, who are much stronger than the Naboo guard. An army like that must have taken years of training and manufacture to put together. Who were they planning to use it against? It can't go into Space so was it for other Gungans? Or should the Naboo be a little suspicious of their allies in the swamps?

[Assistant]
This is a bit like asking if Mexico should be suspicious of the United States' military. Probably yes, but there isn't a lot they can do about it.

The Gungans have a proud military tradition, and (prior to the Battle of Naboo) were pretty xenophobic. Their army was also more of a militia than a standing army, its primary role was to stop the bigger fish from trashing their city. In addition to that, the Gungans (again, prior to the Trade Federation getting involved) weren't really allied with the Naboo. The two groups were only allies in the sense that the Gungans didn't care enough about the Naboo to wipe them out.


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

[User] ELI5: Why are razors in apples the most widely-known danger of Trick-or-Treating, when there's no documented case of it happening?

[Assistant] Its an amazing example of media fear mongering. When theres no news, you create news. Whats a better way to get viewers than a special horrible thing everyone will have to hear about to be safe. Bonus points because you can attribute your coverage to it not happening anymore (even though it didnt happen in the first place)


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

[User] [Harry Potter] If the Sorting Hat in it's wisdom placed Draco Malfoy into Gryffindor how might things have turned out for him?

[Assistant]
Well, he wanted to be a Slytherin, and almost all the Gryffindors would either bully him or just refuse to associate with him. He's kind of an entitled dick.

McGonigal is not a horrible person, but she doesn't respect the way Draco does things. He has to wait until second year before trying out for Quidditch.

He's a decent player, with a high-class broom. Not a better Seeker than Harry, but he may be good enough to be a teammate. Depending on how that goes, he could get a grudging friendship with Harry going, or at least earn some respect from his fellow Gryffindors. Remember, Quidditch score translates to House Points (for some stupid reason), so helping win the House Cup is well appreciated.

However, I'd predict being isolated from the Slytherins and ignored by the Gryffindors would turn him bitter and even easier to turn to the Death Eaters after the Dark Lord's inevitable return.


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

[User]
[FMA:Brotherhood] Does Al know more about human transmutation because he sacrificed more of his body compared to Ed?

In Ed's case, he went through the Gate and was shown everything but was cut off. Then he mentions he's almost there to knowing the secret to human transmutation but his sacrifice (his leg) was not enough of an exchange.

I assume Alphonse also went through the same thing and since he sacrificed his body, does he know everything? If he didn't go through the same ordeal, then what did he and the Truth talk about? How can he transmute without circles?

[Assistant] I believe when Ed is talking with Izumi they agree Al must have seen more of the Truth than either of them because he lost his entire body. However, the ordeal was intense enough that Al cannot remember it.  He does eventually remember some (since he no longer needs to draw Transmutation circles), but it's unclear just how much he remembers and whether or not it is more than Ed and Izumi.


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

[User] ELI5: Why does the whole stream change it's course when you run water from the faucet and barely touch the side of the stream?

[Assistant]
The viscosity (the way the water particles try to stick together) of the water means that when a few particles are diverted, they pull on the other particles around them and it turns into a chain reaction of movement. Imagine pinching a tubular curtain about halfway between and the floor and the ceiling and pulling it up. The bottom of the curtain would hang under your hand and the other side would move similarly, because it is all attached. A choppy analogy, but a visualisation none the less.

Also, it has a lot to do with the differing currents of the water stream pushing it all around.


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

[User]
Since electromagnetism is so much stronger than gravity, why doesn't it have more of an effect on large celestial bodies?

Since bodies like Earth, Jupiter and the Sun all have powerful magnetic fields, why do we not see the orbits of large bodies shifted by the magnetic fields of one another? Indeed, *do* we see this at all?

After all, even a tiny magnet can defy the gravity of an entire planet by lifting a kilogram weight off a table, and an  electromagnet in a scrap yard can lift an entire car. Why, then, does this apparently-more-powerful force not propagate out into space more effectively than gravity?

[Assistant]
Excellent question. The fundamental reason is because there is no such thing as negative mass. Let me explain. Electric charge can come either as positive or negative, and opposites attract. This means that free positive charges will tend to attract free negative charges until they bind to form neutral atoms and molecules (or more exotic composite objects). When bound together, the electric and positive charge are so close to each other that for the most part they cancel each other's effects. To a first approximation, a system with an equal amount of positive and negative electric charge acts like an electric dipole. The electric field of an electric dipole dies off with distance according to 1/r^3 . In contrast, the electric field of a bare electric charge dies off with distance according to 1/r^2 . On astronomical scales, r is huge, so that that the electric field due to a dipole (and by an extension, a neutral molecule) is far weaker than the electric field due to a bare charge. Since opposites attract, most of the electric charge on a planet is bound up in neutral atoms/molecules. For molecules that have a weak dipole moment, the electric field falls off even faster than 1/r^3 . The situation is even worse for magnets. Magnetic poles *always* come in pairs, so that the magnetic field of a magnetic object always dies off as 1/r^3 or faster (as long as you are sufficiently external to the object - inside magnetic objects/systems you can get all sorts of fields).

Now let's turn to gravity. Since there is no negative mass, there is nothing to partially cancel the gravitational field of positive mass. Therefore, the strength of gravity of a localized mass always dies off dominantly as 1/r^2.

In summary, electromagnetism is stronger than gravity, and they both fundamentally die off with distance at the same rate (1/r^2 ), but due to the existence of negative charges/South magnetic poles and not negative mass, in most practical situations, electromagnetic fields die off much quicker with distance than gravity. The distances involved on astronomical scales are so large that gravity dominates.

In principle, if we could make an entire planet out of just electrons (if we found someway to turn off their mutual repulsion), the electric field of this planet on astronomical scales would be immensely strong, far stronger than gravity.


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

[User]
[Halo] How were energy shields distributed to covenant forces?

Im kinda confused on how the covenant handled energy shields. Im talking purely lore now. I dont read the books so maybe theres a clearer answer there. In Reach when noble team first encountered the elite zealot team, we see that their shield can take a lot bullets before dropping. In the Halo 4 intro, we see that the regular elite shield just dropped after one or two bullets. So does the higher ranked elites get better shields? Similar to how human special forces gets better equipment than regular infantry. Did other races receive energy shields too?

[Assistant] Yes, there are lots of different armor models. This should be pretty obvious. In Halo 2 one of the elites comments that the Arbiter's antique armor can't cloak as long as their armor. In Halo 3 brutes start using shields because the elites defect. Jackals are issued portable arm-shields instead of full-body shields, likely because they're easier to mass-produce.


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

[User] How was it decided where astronauts would land on the moon?

[Assistant]
Based on what a professor in a planetary science class explained to me:

 * Step one: Send unmanned orbiters to take large, low-resolution photos and make a global map
 * Step two: Give the map to the geologists and rocket engineers and have them argue about the most interesting vs. safest place to land, come up with a list of candidate landing sites
 * Step three: Send more unmanned orbiters to take high-res photos of the candidates
 * Step four: Same as step two, with more information on each site

Of course there's other constraints and tools used as well.  Since the moon is so close you can get a lot done with ground-based telescopes.  On the other hand they knew they would be landing on the near side of the moon so they could have a direct line of sight back to Earth for communication.  Stuff like that.  But this same basic process is used for exploring any planet, whether it's Mercury or Titan.


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

[User] Why does electricity usually spread itself in a zig zag pattern when there's no concrete path to follow?

[Assistant]
I assume you're talking about things like lightning.  Ordinarily, air is extremely resistive to electrical current flow.  But, when the electric field is strong enough, a narrow channel will ionize and conduct current.  This allows charge to advance a short distance, where the electric field builds up again, causing another ionization to occur.  Each breakdown happens in a semi-random direction (more or less following the background electric field, but not completely) and creates a narrow ionized channel.  This means that the full path taken by the current is a series of short, semi-randomly oriented steps--a zig-zag.

Importantly, following the path of least resistance is not very helpful for describing this.  By ionizing the otherwise resistive air in steps, it CREATES the path of least resistance, and does so in a chaotic way.


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

[User]
[Mostly Marvel, but some DC] Why do so many villains wear purple and green?

Galactus, Green Goblin, Kang the Conqueror, Mysterio, the Joker, the Riddler, the Leader is pretty green, Magneto (no green, but plenty of purple), Dr. Doom (no purple, but plenty of green)...and I'm sure I'm missing some others. Anyone have any good ideas why all of these baddies prefer green and purple?

My working hypothesis is that it's to balance out the overabundance of red and blue in the superheroes' uniforms, but I was wondering what others had to say about it...?

[Assistant]
Purple it a color traditionnally associated with royalties. It instinctively give a feeling of power and authority. Therefore, villains who often aim at controlling the world are naturally attracted to thsi color.

Green on the other hand is a color that reflect greed and envy. Feelings also very strongs amongst villains.


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

[User]
How large will a human fetus get if the mother never goes into labor or gets a Caesarean section?

Will the baby continue to grow until the mother dies from the size?  Is it possible that a mother give birth to a child that is a few years old?

[Assistant]
No - in fact, if the child stays in the womb much beyond 40 weeks, they will die. The placenta gradually stops working as you get beyond 40 weeks or so, and without this, the child gets no food or blood (among othr things).

This is why obstetricians will generally induce delivery or perform a Caesarian once you get past 41-42 weeks (depending on local practice).


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

[User] ELI5: How is Chernobyl still dangerously radioactive but Hiroshima and Nagasaki were being rebuilt not even a decade after the atomic bombings?

[Assistant] For a few reasons. The Fat Man and Little Boy bombs detonated several hundred feet above ground level, and in doing so expended only 2 pounds each of their plutonium and uranium fuel. The Chernobyl reactor accident was at ground level and the reactor contained 180 TONS of radioactive fuel.


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

[User]
[Harry Potter/DC] Would the Marauder's Map reveal Joker's identity in Hogwarts?

Simple question, really. In light of recent debates in this subreddit about Death Note vs Joker, I thought Harry Potter might be able to chip in and help if he had his Map readily available.  If i recall correctly, the Marauder's Map only works within the boundaries of Hogwarts, thus would  it reveal the Joker's true identity? Yes/No question, but I wanted to see if there's any canon counter-evidence if any.  Also, I think someone somewhere said Batman actually knows Joker's real identity. Not sure if true or not, but irrelevant with this question.

[Assistant]
Magic isn't quite bound by the same rules as human logic. The map could discern a person's identity very easily unless confused by some sort of magic meant to conceal the user; simply calling yourself by another name would mean nothing to the map, as an alias is a thoroughly non-magical form of concealing one's identity.

Case in point: Peter Pettigrew. He was living as a rat at the time, under the name of "Scabbers". Definitely an assumed identity, yet the map labeled him by his true name with no trouble.

Now, your question begs a more interesting hypothetical, namely "How would the map react to a person who had never been named?" For example, a newborn baby whose parents had not yet had the chance to name him or her.


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

[User]
ELI5: Why do a lot of animals love good pats on their head, even when they are NOT domesticated?

There are videos of a lot of wild animals getting a good pat on their head, seemingly enjoying it. Or maybe its a good stroke over their necks, or being cuddled. Preys and predators alike. What evolutionary advantages drive them to act this way?

[Assistant]
Rubbing or nuzzling is often a sign of affection or bonding for a large number of mammals. Even birds can preen each other to bond, in some cases. But not all wild animals get any kind of good feeling for rubbing. For example, most lizards and fish do not care at all about that kind of attention. A dew fish might do some grooming to remove parasites so those ones might enjoy some touching since it would normally mean they are being cleansed of parasites, so they have an evolutionary pressure to seek out (and thus enjoy) such situations.

Of course, non-domesticated animals are usually (and *should* typically be) timid around humans, so they usually aren't just going to walk up looking for pets.


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

[User]
ELI5 Brute Force password attacks; wouldnt they get locked out?

I understand how password length and character exponentially increases the time necessary to brute force the answer.

Question is how do the attackers get around all the various hurdles and lockouts that every site seems to have?  If they dont have some trick for getting around the lockout, wouldnt the account just get locked within the first few tries and theyre done?

Wouldnt somebody on the backend notice all the attempts?

[Assistant]
Generally speaking, people aren't brute forcing passwords by shoving them into a webform.

Instead, here's what will usually happen.

First, years ago you will have signed up for some random website that has moderate security at best. The email address and hashed password are part of that site's database.

Then, that site gets exploited in some way, and that database of emails and hashed passwords is made available for the right price.

Then, someone buys that database and starts cracking passwords. They try password after password until they can match what's in the database. There's no lockout system here, since that's a software layer put in top by the website that would normally be using this database.

After they've cracked enough passwords, they'll sell known email/password combinations. Other people will try those email/password combinations on other websites, hoping that you reused the same password in multiple locations.


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

[User] [Dragonball] Humans shed cells all the time, cells regeneration only requires a few cells, how is it even possible to kill him in the first place as wouldnt he have cells just lying around?

[Assistant]
Skin cells are already dead when you shed them, so presumably everything outside the gigantic Kamahameha was already dead by the time Cell got blasted.

They can't stay alive and viable for regeneration indefinitely, otherwise there would be a
million Cell clones hanging out within a week or two.  Sorta like an Ork infestation.


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

[User] Why do eyelids tend to close when the tongue tastes something really sour?

[Assistant]
The function of the disgust expression is to stop noxious stimuli in the environment from harming us by entering one of the orifices on the face.  That's is why the nose wrinkles, the tongue protrudes and the eyes close.

This physiological function was first proposed by Darwin (1872).


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

[User]
ELI5: Why are land/real estate lease agreements often for 99 years?

Everything from Hong Kong, Daewoo in Madagascar, to housing in Singapore. Why exactly 99?

[Assistant] In much of the English speaking world, or at least parts of the world where the judicial system has some connection to merry olde England, an old legal doctrine called the Rule Against Perpetuites was part of common law.  There is no way to properly ELI5 the RAP other than to say it was designed to stop the "dead hand" from controlling property more than a generation or so after the original owner died.  In order to conform to the RAP, a 99 year lease was developed, and in most cases, it was deemed not to violate the RAP.  In modern times, the RAP is more or less defunct, but the tradition of a 99 year lease was established and continues mostly due to practice and convention.


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

[User]
Eli5 Why we cannot build a sleep surplus?

A previous posters question raised another question for me. I understand that human beings can experience sleep deficit, but why can we not build up a sleep surplus?

[Assistant]
One of the main purposes of sleep it to allow our bodies to recover from the day and do a bunch of normal "maintenance" tasks that need to get done.  Some of that stuff just needs to be done every day.

Like, imagine you generate one trashcan's worth of trash every day.  You can empty it once a day and be fine, or you can empty it twice a day and be just as fine.

What you _can't_ do is empty it twice today and skip emptying it tomorrow - by the end of the third day, trash will be overflowing everywhere.  No matter how many times you empty it in a day, it still can only hold one day's worth of trash.  You can't build up an "empty trash" surplus.


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

[User]
[Warhammer 40k]Why do eldar make everything so unnecessarily complex?

Lets look at their night spinner anti gravity tank's main gun.

>The Night Spinner grav-tank mounts a Doomweaver atop its sleek chassis, a weapon that spins threads of monofilament wire into a lethal web that is launched high into the air. This monofilament mesh is made from an organic polymer compound. The compound is kept in a liquid state within a magnetic reservoir, and when released through the thousands of microscopic firing ducts, it is woven into a web-like cloud by spinning gravity clamps. This substance is incredibly thin, and yet so strong that nothing can stop its inexorable descent towards its victims. Indeed, the threads are known amongst the Eldar as the "Chain of Vaul," named after the unbreakable bonds of legend. Anyone or anything unfortunate enough to lie under a Night Spinner's ghostly web will be shredded by the simple actions of gravity drawing the cords downwards. The strands can even cut through steel, so vehicles caught by the web are likely to be snared and damaged, if not destroyed. It is not uncommon for the monofilament threads to shear clean through turrets and weapon barrels.

This sounds like a lot of trouble at the field. So many things to go wrong.

Why not just use a god damn laser based weapon or just shells?

[Assistant] Because the Eldar had millennia of boredom of which to invent unnecessarily complex devices. Sure they could just get the job done but the Eldar havent had to deal with resource scarcity, actual enemies, or mortality since the War in Heaven. So they spent those years seeing how far they could push. Sure sticking explosives into a metal shell kills stuff just as good but isnt using molecule thin wires to cut everything in an area into ribbons cooler? And if you dont have to worry about actually loosing why not just invent cool shit to use against the lesser races?


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

[User]
ELI5: How is Grand Theft Auto 5 able to have such a large map, but little if any load screens?

Most games I've ever played have to load every time I enter a new area. How does Rockstar bypass this?

[Assistant]
All of the map's data is available, but not always loaded.  Instead, the game loads only what is pertinent to the player and the information is left behind once it becomes irrelevant.  You can truly notice the effects of this when travelling very quickly across the map, such as in a plane or helicopter.  You'll notice structures start to appear on the horizon of your vision as the game loads them.  The faster you're travelling, the more abruptly these objects will appear to load, because you're giving the game less time to load them!

This explains why many of your actions seem to be reversed if you leave an area for a little while and then return--what's happened is that the game has discarded the information from your last visit and has reloaded everything.  GTA V cannot be a truly persistent world for this reason.


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

[User]
ELI5: The Missing Dollar Riddle.

Three people check into a hotel room. The clerk says the bill is $30, so each guest pays $10. Later the clerk realizes the bill should only be $25. To rectify this, he gives the bellhop $5 to return to the guests. On the way to the room, the bellhop realizes that he cannot divide the money equally. As the guests didn't know the total of the revised bill, the bellhop decides to just give each guest $1 and keep $2 as a tip for himself. Each guest got $1 back: so now each guest only paid $9; bringing the total paid to $27. The bellhop has $2. And $27 + $2 = $29 so, if the guests originally handed over $30, what happened to the remaining $1?

[Assistant] The $27 paid includes the $2 tip, so adding them makes no sense but the riddle confuses you into thinking that it does. The original $30 is made up of the $27 paid ($25 to the hotel plus $2 tip) and the $1 each they got back.


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

[User]
ELI5: why do computers sometimes make horrible buzzing sounds when crashing/locking up?

Just had this happen to me for the first time in a while and it always catches me off guard.

To give my example, I was listening to music on my PC, and mid-song the PC completely locked up and a loud buzzing sound came through my headphones. I've had it happen in the past with other PCs and with game consoles as well, but why does it happen?

[Assistant] The sound hardware in a PC is designed to work with as little interference from the CPU as possible. To that end, it's generally set up so it can play a chunk of audio from memory without interference--all the CPU needs to do is update the location the audio hardware is playing from every now and again. If the system has completely locked up and is no longer responding, the audio hardware will often just keep playing the last little bit of sound it was told to over and over again--depending how long that sound fragment was you might get an obviously repeated bit of music, or just a buzzing.


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

[User]
How are dams able to be constructed against the constant push of flowing water?

Secondly, how exactly does a dam hold back a constantly accumulating amount of water without simply overflowing? I know they drain some water through spillways, but it seems like the vast majority of water is still trapped above the dam. Where does it all go?

[Assistant]
Usually the river is redirected around the site where permanent dam construction is taking place. A temporary dam may be used to assist the redirection.

A hydroelectric dam routes some of the water through the turbines within the dam to create electricity. Excess water exits through spillways.

When the lake upstream of the dam has reached the target level, the dam engineers allow water to flow downstream, else the damn would overflow. So at some point in time, the water exiting through spillways (and turbines) is equal in volumetric flow rate to the amount of water entering the lake that has formed above the dam.


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

[User]
Do you have an internal monologue?

I have one constantly myself. Im always thinking to myself. I thought everyone one earth always has been and always will be like this, but I found out yesterday not everyone has an internal monologue. Some people dont have one at all. This BLEW my mind. I cant imagine what its like to not have one. I cant figure out how the other side of the coin works, or functions, or processes.

Im curious to learn more about this.

Im curious how my monologue compares to others monologues, and Im curious to know how people without one tick.

I want to know if those without an internal monologue can comprehend or fathom having one, as I cant comprehend not having one.

Shoot me a message and lemme know if you do or if you dont, if you do how active it is!

[Assistant]
Ok, its like this, hear me out.

What people dont realize is that, we sorta still do have one, but one that most people arent very conscious of. But you can think if it like, instead of it being in the language of English, its by another language weve learned. We think in the language of feeling.

Heres sort of an example. If specifically YOU looked at the stove and wondered whats cooking on the stove?, you would probably hear yourself asking in your head. But what invoked you to think that? For a brief moment even you had a period between looking at the stove, and asking yourself the question. In that moment you FELT curious, which invoked you to ask yourself.

That feeling is usually the end of the line for people. Most people can interpret that feeling for what it is, but if you cant for whatever reason, youre brain will have you interpret the feeling into a sentence to better understand it.


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

[User]
What exactly is Particle-Wave Duality of Light?

I have read a little bit about Quantum Mechanics and this is a bizarre phenomenon(for someone who didn't take GCSE Physics) that I've come across that isn't explained very well.. So I was wondering if someone can perhaps provide me with a more comprehensive explanation with suitable analogies so that I have a better intuitive understanding of the subject.

[Assistant]
Waves and particles are concepts that have quite different properties.

The following are simplistic representations of some of the classical properties of waves and particles:

Waves are considered to be entities that don't have a single position, but are instead spread out over an area. In addition, two waves can interfere with each other and depending on the conditions, this interference can amplify the wave or even extinguish it. A wave can even interfere with itself, for example through it's reflection (throw a pebble in a body of water and you can see the interference of the wave with it's reflection off the edge of the water).

A particle is a discrete unit. You can count them. They have a single, well-defined position and direction. While different particles may interact, they do so in an intuitive way, according to classical mechanics. A good analogy for particle behavior and interaction is a pool table, with the balls (particles) moving around and bumping into each other and the walls.

Whether light consists of particles or waves has been a back-and-forth matter in science. In the 1800s it was discovered that light is a form of electromagnetism and through the work of Faraday, Maxwell and others, light was established as a wave phenomenon.

However, in the early 20th century quantum theory reignited the notion of light as a particle phenomenon. Work by Einstein and later Compton revealed that light had properties that could be explained through particle theory, but not with wave theory.

Eventually quantum physics evolved and the differences were reconciled with the conclusion being that light exhibits properties of both waves and particles. Depending on exactly what you're looking at, you'll find light behaving like a classical wave, like a particle or like something that's neither of those two.

For example, in the dual-slit experiment, a light source is directed at an opaque surface with 2 parallel slits in it. The light passes through the slits and is projected on a surface behind it. Doing this reveals interference patterns that are consistent with classical wave theory, but can't be explained with pure particle theory.

On the other hand, in some instances, light can be measured not as a continuous wave, but instead as discrete units of energy, as if they were separate particles. One instance of this is the photoelectric effect, a phenomenon where certain materials emit electrons when exposed to light. This phenomenon was first explained by Albert Einstein (for which he won the Nobel prize), by considering light as discrete "quanta" of energy.

So there you have it. Particle-wave duality of light means that light behaves as both particle and wave, depending on the situation. However, classical particle and wave theories are insufficient to completely describe light, which is where quantum mechanics comes in.

And as an encore: It's not just light that exhibits particle-wave duality. It's everything. The aforementioned dual-slit experiment also works with electrons, for example. In general, the heavier/bigger something is, the less pronounced its wave aspects are, which is why we don't have to consider the wave properties of macroscopic objects at all.


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

[User] [Home Improvement] How has Tim survived into adulthood being as accident prone as he is?

[Assistant] I assume doing the show increased his rate of accidents by a ton, since he seems to get viewership by being somewhat willing to get into crazy accidents.  Even if he is not doing it intentionally, he does continue to work on the show which requires him to do _potentially_ dangerous work on a regular basis.  It's possible that prior to this he didn't directly involve himself in this type of work frequently.


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

[User] ELI5: The Pros and Cons of Universal Healthcare.

[Assistant]
Pros:

* Everyone has health care coverage.

* Catastrophic illnesses or accidents no longer bankrupt families.

* Theoretically, the state could drive preventative care programs as a way to reduce costs.

Cons:

* It costs money.  Someone has to pay for this with taxes.

* The state gets even more involved in your private life.

* There may be moral hazard attached to getting something for free.


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

[User] ELI5: With the amount of space debris orbitting the planet, how do satellites and space stations mitigate against impacts?

[Assistant]
"Space debris" is a continuum. The frequency of a piece of debris is directly related to the size of that debris - small particles are significantly more likely than huge chunks of matter. Satellites and space stations are just built with enough external shielding to survive the constant onslaught of tiny particles (mm scale and below).

Larger objects than that are **actively tracked**, and if something is on a collision course with a space station we have enough of an advance warning to move the station out of the way using its onboard thrusters. These happen every so often, maybe once every few years.

Also, there's not actually as much space debris as you might think. Space is a big, big place. Even down in low-earth orbit, the chance of getting pummeled by space debris is only really a concern for very long-lived projects like the ISS that survive in orbit for many years. And this is the "high risk zone". Out in the far reaches of geostationary orbit (many times the altitude), space debris is a non-issue. This is where most satellites live, especially communications satellites.


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

[User] How does electricity "know" which path has the least resistance?

[Assistant]
Imagine you have a circuit with two different resistors in parallel, connected to a battery. At the moment you close the circuit (i.e. turn it on), you will have electrons leaving the negative side of the battery. They will push against the other electrons on the wire, which will then push on the next ones, etc. See, the thing is, electrons do not move fast. The "drift velocity" of electrons is of the order of mm/s in DC current.

So what you have isn't something really "flowing" through like cars or a river, but things "bumping against eachother", like people rushing in a Walmart on Black Friday. The bigger door (smallest resistance) will have more people (electrons) going in.


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

[User] ELI5: what are birthmarks and why do they appear?

[Assistant] A birthmark is a congenital, benign irregularity on the skin which is present at birth or appears shortly after birth, usually in the first month. They can occur anywhere on the skin. Birthmarks are caused by overgrowth of blood vessels, melanocytes, smooth muscle, fat, fibroblasts, or keratinocytes.


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

[User]
ELI5 - Why is it bad for money to have a fixed value over time?

What's the harm in a dollar's worth being constant? Why is an inflation rate of zero bad?

[Assistant]
Having inflation increases investment, it makes it disadvantageous for you to have  tons of cash just laying around. In fact a big problem now is that companies and people are hoarding cash, with inflation there's a big push to invest in things such as an expansion or hiring new employees, because you effectively lose money if you do nothing with it.

0% inflation isn't necessarily bad, its just not optimal, but negative inflation is terrible and was one of the biggest issues in the Depression. Farmers were burning their crops because the prices were so low it wasn't even worth selling them, while people in the cities starved. You can see something similar today with the housing market, where no one wants to buy because the prices keep falling.


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

[User]
ELI5: When watching a painful video (ex: a bicycle crash), why do our nerves seem to become active, as if we are feeling the pain ourselves, for a split second?

Not sure this is common but its not always pleasant.

[Assistant]
2 possible reasons.

1) Humans have special kinds of neurons called mirror neurons that allow you to "feel" in a limited sense what other humans are feeling. This is helpful to build empathy and lasting relationships.

2) Our brains are also constantly learning and trying to simulate the effects of the environment on ourselves by observing other humans. For example, if you can learn to avoid a lion after seeing what happens to another human being mauled by a lion, then that's good for your survival. If you "feel" the other guy's pain, you will learn to avoid the lion in the future. So in a sense, when your brain sees a terrible accident happen it simulates the effects to some degree on your own body in order to teach itself to avoid the said danger.


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

[User]
[40k] Is Chaos corruption alone enough to bring Chaos Space Marine creation up to replacement levels?

Or are Chaos Space Marine numbers being slowly depleted as the original traitor legions die or turn to Chaos Spawn?

[Assistant]
The numbers of the original traitors are being slowly whittled down - although not as quickly as you might expect, since some of them get resurrected due to Warp fuckery.

However, they're also always recruiting. They still have gene-seed, and armies of cultists who would cheerfully volunteer to have it implanted into them. Fabius Bile is constantly performing perverted experiments to make new Chaos Marines.

On top of that, the Heresy was the biggest incident of Astartes falling to chaos, but it was far from the only one. Few outside of the Grey Knights are completely immune to the temptations of the Ruinous Powers, and it's not unknown for entire Chapters to fall to Chaos (most famously the Astral Claws/Red Corsairs, under Lugft Huron/Huron Blackheart, the Tyrant of Badab).


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

[User]
My professors never taught be the basics of writing for academic journals. What book should I read in order to teach myself how to write articles for journals?

I did a BS in Economics and an MBA from Bangladesh. I was extremely interested in research and I still am. But my supervisor and professors were dismissive of my interests considering me overconfident and "someone who thinks they are great researchers or can be" (someone too full of themselves). In any case, they were interested in test scores and rote learning and never on research. I did one semester of course in research in my undergrad and the supervisor only brushed through the basics.

I am thinking of starting my own research and writing my own articles and maybe try for PhD. I know it might not be possible with such scarce hands on training but I really want to give research article writing for journal articles a shot.
I know longer have access to the library at my university so I cannot get books on loan. Also, academic books are prohitively expensive given the exchange rate, import duties and the insane amount of red tape surrounding the outflow of foreign currency from the country. So, I am preferrably looking for a free book(s) on how to write research articles and to know the intellectual property rights regarding my work.

I want to learn how to write articles for journals and I am looking for books that will teach me how. Can someone suggest some brief yet comprehensive books that I should read to teach myself how to write research articles?

[Assistant]
You seem to come from a very 'taught' background rather than a research one. Did you have research oriented dissertations or thesis? If so, publishing that could be your first target.

I would suggest start by reading the articles in your field and target journals. It is English and you can learn a lot from just reading and noticing how they are structured and what information they cover.

I am not aware of any Academic Publishing for Dummies kind of books, but to be honest, you don't need them.


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

[User]
CMV: Property taxes are the most unethical tax there is.

I understand the concept of owning land and paying a fee to the state for occupying such a limited resource but the part I do not agree upon is having your home included in the assessment.  If you want to turn that walk-in closet into a bathroom you have to pay a perpetual fee for bettering your home.  That's really all it is: a continual fee for improving your living space.  Think about how crazy that is. If I decide to spend my own money to build a new deck, the state makes me pay an additional fee, in perpetuity, as they somehow claim ownership to a small portion of the added value of my home that came at MY expense.

Again, I understand, and agree with, the basic premise of property taxes.  We as the owners of a limited amount of land in a community have a shared responsibility for the upkeep of that same community, in which we reside.  But how can the local government act as if they are owed more money should YOU decide to update that land on your own dime?

[Assistant]
I agree that a land\-value tax is the conceptually cleanest, and arguably least distorting kind of tax, but there are a few solid reasons why including structure\-values in the calculation improves on a land\-value tax on some metrics:
1. Usage of public goods\- an empty plot of soil is far less likely to use underground water supplies than a farm that digs into the water table to irrigate; a shack is going to use far less firefighter time than a mansion; a single\-person house is going to use far fewer police and public school services than a sky\-scraper with a thousand people.  Sure, you can add separate taxes for each of these resources, but that's far more complicated that just picking a proxy like "struture\-value" that correlates with all of these things.

2. Allowing small farms and other traditionally respected heavy land users to keep functioning \- if we were to change the scheme to land\-value only, all of a sudden a lot of businesses would have to shut down because they had bought their land on the assumption that taxes would continue to function as promised.  The change would be unfair because it breaks an implicit promise, and potentially unsavory because we would have to shut down certain institutions we have come to value (maybe even if they are not the most efficient users of land).

3. Progressiveness of taxation\- if you accept that there is a lot of luck involved in whether you happen to become a millionaire (even if you are just talking about ovarian lottery luck, of happening to be born with good genes and family), then you might reasonably choose to live in a world where if you happen to be born lucky you are willing to pay more for public goods, in exchange for having to pay less if you are unlucky (aside from fairness, this also results from the marginal dollar being worth far less to a millionaire than someone poor).   One good way to get rich people to pick up more of the tab for local schools and other services is to charge people with expensive houses more.


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

[User] ELI5: How is something thats shaped as strangely as the anus able to be air-tight?

[Assistant]
Pucker your lips like you're trying to make an exaggerated kissy face. Notice that it's still air tight. Your butthole and your lips are pretty identical in terms of shape and construction, cept they're on opposite ends of a really long pipe.

Bonus fact: kissing someone is basically just making a really long pipe with an asshole at both ends.


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

[User]
[LotR] Why do wizards take the form of men, rather than dwarves or elves?

In many ways, Gandalf seems closer to elves than to men.

[Assistant] Because it was in Men that hope for defeating Sauron lied. All other beings were bound to Arda and its fate; only Men had the ability to forge their own destiny. Since the Istari were sent to aid (indirectly) in the battle against Sauron, they needed to assume a form that would best interact with Men.


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

[User] ELI5: what does this saying mean? I can't get my head around it: "it pays to kill with kindness when you're your own worst enemy"

[Assistant] Who would most people love to kill? Their worst enemy. If you were your own worst enemy and you choose to kill with kindness, you would be extremely kind to yourself. Therefore it "would pay." Essentially it implies being extremely kind to yourself.


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

[User]
Are planetary rings always over the planet's equator?

I understand that the position relates to the cloud\disk from which planets and their rings typically form, but are there other mechanisms of ring formation that could result in their being at different latitudes or at different angles?

[Assistant]
Large spinning bodies form an equatorial bulge.  There's more mass around the equator, so given enough time any body in orbit will settle into an orbit about the equator.  A ring formed at a tilt from this would be unstable and would migrate towards the bulge.  Uranus for example has an extreme tilt, and its ring system aligns with its equator.

Venus rotates so slowly it doesn't have a significant equatorial bulge, so potentially it could support a ring system with any degree of tilt.


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

[User]
If I consumed excess salt in my diet, could I counteract this by drinking an extra glass or two of water?

Is there any method to counteract eating excess salt?

[Assistant]
The only bad thing about eating too much salt is that it raises your blood pressure by helping your body retain water. If you drink more water with your salt, you'll actually increase your blood pressure more. So actually the way to "counteract" too much salt is to take a diuretic so you'll urinate more and get rid of the excess water, as well as the excess salt. But then if you do that, you also get rid of potassium, which you're probably not eating excessively, leading to an imbalance with respect to sodium and potassium. These two elements are essential in many processes in your body, notably in the regulation of the heart beat and in the working of muscles. This is why marathoners die when they rehydrate with plain water instead of water containing sodium and potassium.

So basically, it's just a lot easier to not eat so much salt.


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

[User] ELI5- Why is it that can some countries can have nuclear weapons while others can't, and who gets to decide?

[Assistant]
Pretty much everyone got together and agreed to A. Stop building nukes B. Get rid of the nukes they have (this has been progressing slowly) C. Share nuclear technology for energy purposes.

The big countries benefit from number 1- no new nukes, so the balance of power swings more towards them. Less powerful countries like 3- they get free technology and don't have to rediscover nuclear power on their own if they want to have their own reactors.

Not everyone signed the treaty- in particular, India, Pakistan, and Isreal. The first 2 have publicly shown that they have developed nukes, and everyone is pretty sure about Israel.

Iran *did* sign, which is why the UN is allowed to care about their nuclear program.


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

[User] ELI5: Why are there so many gun models using the same calibre? Doesn't the bullet determine most of the lethality and range, while the gun is just the vehicle that fires it?

[Assistant]
The cartridge itself is the main factor in terminal ballistics, but barrel length is also important - a longer barrel gives the bullet more distance to accelerate, to a certain degree.

That aside, there's also plenty of other factors in a gun. Ergonomics, rate of fire, price, the action and lock type, materials, safety, other features to improve reliability or ease of use, the list goes on. Also, some models may be updated versions of older designs, direct competition to a similar model or just an improved but more expensive luxury version.

Think of it like there being lots of models of cars that use the same fuel.


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

[User]
ELI5: Why livestreams (Twitch, Youtube, etc) have such a clear and smooth quality while video calls (Skype, etc) are so laggy and low quality?

I watch a Youtube channel called Funhaus and they often stream using their webcam and the quality is perfect (also used for recording). They also play games with other Youtube channels and they use Skype to chat with them before and after matches, but the quality is incredibly bad. Why?

[Assistant] Because you aren't watching them "live". There's a delay corresponding to the amount of time it takes to send the data to the streaming services, then to you. Once the streaming service has the data, they can stream it to you unhindered. The delay allows for perfect playback. Because a long delay wouldn't be acceptable with video chatting services, this method can't be used, and the data has to be streamed at a lower quality or with chunks missing to eliminate delays as much as possible.


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

[User]
ELI5: Why is it that we need to basically 'fast' for 24 hours before going into surgery?

I have always wondered how having very little food in your stomach affects a surgery.  I'm sure this concept is irrelevant in emergency surgery situations, so what are the implications?

[Assistant] Anesthesia can make you very nauseated, and they don't want you vomiting while you're unconscious.  Also, your organs "wake up" at different rates, and it's important that your digestive tract be able to engage in effective peristalsis to move food down the canal.  Otherwise, you'd have lumps of decomposing food in your digestive tract, constipation (another side effect of anesthesia), and bloating and cramps from the offgassing because the peristalsis wasn't squeezing it along.  Same thing goes with pets, which is why you have to withhold food and water for a time before surgery. It's a smaller consideration in emergency surgery, as you mentioned, but if you have the ability to prevent it, why not?


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

[User] ELI5: Why do some Americans treat the their constitution as a borderline religious text?

[Assistant]
The United States has, since it's founding, taught it's schoolchildren the nation's history as a series of *narrative stories*. Discussions about the American revolution don't discuss the implications of post-war reconstruction on regional stability until the college level. As children, they learn about the Ride of Paul Revere and narratives about oppressed people being free.

In those stories, the US founding fathers take on the role of the Knights of the Round Table, acting as perfectly just rulers who advocate equality, bravery, and good government. It's designed both to inspire patriotism and to help kids to remember some of those early laws and ideas by presenting a simple narrative of Good and Evil as a mnemonic to remember them by.

As people grow up, the heroic tales of the Founding Fathers remain a part of their patriotism, and they feel a great attachment to the principles that those men said were sacred. The US constitution nevertheless changes frequently, with the latest change in 1992. Most of the changes to the document don't involve the 'core principles' of Right and Wrong that American schoolchildren are taught to remember though. Generally, when people say 'the constitution is a sacred document' they mean things like Freedom of Expression and the Right to Bear Arms rather than how the US constitution handles a sudden vacancy in the vice presidency.

In other words, the Founding Fathers are a channel for people's political opinions surrounding right and wrong. When they are morally outraged by a law, they argue that the Founders would be. When they are okay with a change, generally they figure the Founders would, with today's evidence and information, be okay with a change too. Their actual opinions have very little bearing unless people still agree with them. For example, many of the Founding Fathers supported slavery, which we don't really talk about anymore. But when a quote can be found that matches a Founding Father with your opinion, it makes you feel really patriotic, so people quote them all the time.

Plus they were some quotable gentlemen. Very literary, good command of language.


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

[User] [SCP/Harry Potter] If we assume the Foundation secretly knows about wizards and takes a hands-off approach to their world, what potential "Plan-B" backup plans might they have ready just in case?

[Assistant] Wizards aren't really an X threat and they police themselves. Not really the foundations business, though were they to exist in the same universe they would likely get hired to boost the security of several facilities.


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

[User]
ELI5: Why does cheese shredded from a block taste better than pre shredded cheese from the same brand?

If you buy a block of cheese and shred it at home, the shredded cheese always tastes better than pre shredded cheese from a bag. Why?

[Assistant] Because pre shedded cheese has a starchy coating to stop it all sticking together. Self shredded cheese doesnt have this. Its also why certain recipes, macncheese especially, call for freshly shredded and not pre bought.


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

[User] ELI5 what mutually exclusive means?

[Assistant] Mutually exclusive is the condition where two things can not both be possible because of the other.  Imagine flipping a coin.  The coin landing heads and the coin landing tails would be mutually exclusive because it's impossible for both outcomes to happen.  The coin must land on one side or the other.


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

[User]
Advice for dealing with toxic fellow graduate student(s)

*Thanks in advance for any advice. I've been blessed with un-dramatic, secure, and emotionally mature friends (which is great), but it's left me unsure how to handle all of this. At this point, I mostly just want to be rid of the drama. Also, if anyone has any suggestions on making friends in grad school (particularly outside of their grad program), I'd really appreciate it. If you want/need details on my specific situation and why I'm asking, see below.*

I started my Ph.D. last year, which wasn't the easiest time to move and begin a new program. Against the odds, I made friends with a few fellow students last February. Everything seemed great. However, a couple of months in, one student in particular (I'll call her A) started displaying some toxic behavior.

At first, it was things like subtly putting down others when they did well or did a homework problem correctly when A got it wrong. Then it was talking about other friends in the group (particularly a young woman I'll call B, but everyone) behind their backs. The badmouthing could take a lot of forms. For example, she would say that B's fiance (who proposed to her last semester) was an alcoholic and a drug addict (he's not) and that we would probably need to hold an intervention when the relationship hit rock bottom in a couple years. She spoke horribly about B when they got engaged (what did she see in him, he's awkward, B is settling, B just got lucky finding love, B's fiance won't be happy with her forever, etc.). Other negative comments included others in the group being immature, liking gossip, being bad/unethical about research, being unproductive, naive, stupid, bad with money, etc. Things escalated when she tried to ice B out of the group (B didn't do something A wanted; A never told B she wanted this thing). At this point, I stepped in and continued hanging out with B despite A. A then decided to make up with B (although she is still mad, even enraged, and will talk about it given a chance). However, B thinks that this was just a small fight between the two of them. She doesn't know that A stopped inviting her to things (and attempted to get me to do the same) or that B still continually badmouths her. B thinks they are still good friends. For some, some definitions of friendship, maybe they are.

After that, I started to realize that A has a history of turbulent relationships. She is not friends with any of her friends from high school or college (her words). She has already fallen out with at least two members of her cohort (she has been here a year longer than I have). Despite this, A is both charismatic and manipulative, which I think enables her to continually get away with how she treats people. In any case, I realized that it was only a matter of time until she got angry with me -- which is what happened less than a month later. I asked her about it after I realized what was going on. Apparently, it's because I wasn't sure I wanted to watch a particular movie and because I corrected her on homework a couple of times (e.g., "I don't think the answer to X can be Y because X divided by Z is not Y" -- I wasn't mean about it). The last two things made her question our friendship. She also told me that she only became friends with me because she felt sorry for me because of COVID, that we only became friends she had recently fallen out with a different friend, and so forth. Just a whole slew of statements that I'm sure were designed to hurt me. I also tried to talk with her about the badmouthing thing, which only resulted in her gaslighting me - she tried to tell me that she hadn't said any of those things, which is just BS because she said them all the time. At that point, I knew there was no recovering the relationship, and I was no longer interested in interacting with her. It doesn't seem worth it.

Here are my questions. However, really any advice or perspective would be great.

* How should I handle this situation appropriately? I see graduate school as being a professional environment. How can I minimize damage? I'm worried about my reputation in the department given A's tendency to badmouth everyone. Typically if I didn't want to be friends with someone I would slowly distance myself by becoming busy with other things, but that seems hard given that everything with A generally seems very dramatic (she spread rumors and tried to complain to the department about one of the students she fell out with last year).
* Does it make sense for me to distance myself from this friend group as a whole? Can I do that in academia or would that count as shutting the door on potentially useful relationships?
* Does B deserve to know? I am inclined not to say anything because I don't think it would do any good, but I've had some friends give me the opposite advice.
* Any tips for how I can avoid situations or people like this in the future?

*TL;DR - I made a toxic friend in my first year of grad school. Now I'm just exhausted from all of this want to figure out a way of distancing myself gracefully and moving on with my Ph.D. without being totally socially isolated.*

[Assistant]
Everyone will learn quickly, if they do not already know, about A's bad behavior. Avoid A and be friends with the others. If B asks tell B in a way that doesn't drag B into the mess any further.

At this point you need to just move on from this mess and get your focus back on important things.

Join a campus group, connect with old friends online, go to social events in your city/town when you can. Avoid A and carry on through your program. A will get herself in her own trouble.


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

[User]
[Alien Franchise] Why would you keep trying to domesticate Xeno's after you have the Ripley "clone"?

I know it was the dream of the Wayland Corp. to somehow domesticate the Xenomorphs into a perfect bio weapon, but after cloning Ripley in Alien: Resurrection, didn't they have something better; a human with enhanced hand/eye coordination, seemingly improved speed and strength, increased aggression responses, and bonus acidic blood!
Rather than an organism they can't control the spread of (see any Alien movie, comic, game), they got an enhanced human that wants to fight, and may be able to understand Xenomorph behavior or biology in a way we can't. They should find out what's different in her DNA, and then work to make those changes onto more suitable subjects (colonial marines) to create a better soldier.

[Assistant]
A human will never be perfect. But they already have the perfect killing organism. A Xenomorph is superior to Ripley-8; it is faster, stronger, and is a more efficient killing machine if used properly.

They needed to extract the Queen from Ripley; the enhancements were pure coincidences. Ripley may have been more bloodthirsty, but she still cared about humanity. It also ties into psychology: to make the perfect colonial marine killing machine, you need a psychopath; and given the amount of time Weyland-Yutani spent trying to extract a Queen from Ripley, the company would need to keep working time after time.

Even then, when will they get a perfect killing organism? At what point will it be perfect enough to kill upon command and restrain itself? When will the Xenomorph DNA work against the company? So many factors that tie into ethics (and we all know Weyland-Yutani has none). They just want one thing: a controllable beast. But tying humans into it will draw unwanted attention from other factions. They'll see the company as a more powerful threat that now showed everyone it is not bound by ethics or morals. It is considered better to use a killing machine that is known for being a killing machine (and efficiently eliminate current threats) rather than bastardized humans and Xenomorphs into attracting attention from other factions (which would increase the work needed to win).


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

[User] ELI5: What is the "basic income" movement?

[Assistant]
It's a movement to create something a bit like Social Security, but for everyone.

Modern society produces a shit-ton of excess resources. In many ways, we could get by without literally everybody working -- unemployment rates, and people on welfare, seem to argue for this.

The idea is that you have much higher taxes, and then use that tax money to give everyone a basic (shitty appartment with roommates?) standard of living.

People would then work since they wanted to do something with their life or because they wanted more money than that.

The proponents see it as a solution to the future where automation may displace most workers permanently, and also that it avoids the problems with modern day welfare where it dissuades people from working, that it is easily defrauded, and needs lots of bureaucracy to get (which poor people have a hard time with.)


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

[User] [Lord of the Rings] Could they recreate the Army of the Dead by having people voluntarily break oaths?

[Assistant]
No.

1. It wasn't the fact that they broke their oath that turned them into undead monstrosities. Isildur's curse did that.
2. Humanity just doesn't have the power to do that anymore by the time LOTR's story starts. The world's magic is fading, Humanity's power is fading, Everything in Arda is slowly progressing towards becoming completely mundane (as, remember, It's framed as being our own world, just before). The Magic necessary to do something like that again simply doesn't exist, unless maybe you're an ancient and powerful Elf Lord, one of the Istari, or Sauron himself. Maybe the Witch King could have done it.
3. Even if that magic *was* still accessible for humanity, It's not entirely clear how it actually worked. LOTR and its associated works don't really describe the rules of magic very clearly (what we call a soft magic system). It's entirely possible that such a curse would require the proper emotional state, or even outright malice, to accomplish successfully, which provides a further barrier to doing it on purpose.