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

[User]
CMV: I think some kind of mechanism needs to exist in social networking websites like Facebook and search engines like Google that ranks content based on truth and whether it can be verified

I'm not one to claim social networking and the internet in general makes people dumber, quite the opposite. People tend to forget that in the past, the dominant form of media consumption was television or the radio and when people partook in either, they did so passively. The internet, at least has people reading, writing, and interacting with information in a more conscious and active way.

What has been increasingly worrying me over the years is effect of content curation algorithms and how confirmation bias, instant gratification, and a lack of (scientific/moral) standards determines the shapes of all our "positive feedback loops", however. I understand why this happened and what the intended function was (a better online experience/targeted advertising) but I think the negative side effects they are responsible for far outstrip any benefit that comes from them. On the one hand, algorithms like this made the vastness of information on the internet manageable in a way that a normal, non-tech savvy person could find appealing. On the other hand, dishonest/morally ambiguous "clickbait" masquerading as journalism or a source of information piggybacks on these algorithms for advertising and other purposes, targeting whatever personality type/group of people online they think they can harvest a lot of page views from.

Consider how many "news" blogs that piggyback on Facebook with hundreds of thousands or even millions of subscribers that know exactly how to pander to people based on whatever pigeonhole these algorithms dropped them in due to how they identify themselves and what their peer network is like (preferences, politics, geography etc). Kind of like your own personal Fox News/tabloid, automatically curated based on what appeals to you specifically, full of "Shocking!" information that is designed to wind you up in order to rope you into advertisement-laden, "clickbait" content. It's not inherently malicious (always), but the effects it is having on people as a whole is disturbing. Particularly with the sort of people who don't put conscious effort into avoiding being stuck in this trap.

Some anecdotes (the first one is something I've encountered a lot):

- If you're a ardent climate change denier, you will end up in an online bubble/postive feedback loop where climate change denial is all you hear whether it's content you searched for via Google or content Facebook curated for you (as Facebook friends who disagree with you are gradually drift out of your feed). Nothing is going to get between you from discovering pseudo-science denier websites like "Watts Up With That?" that are chalked full of misinformation that basically thrive on confirmation bias and morally neutral search algorithms. Such bogus websites that thrive thanks to confirmation bias + positive feedback loops.

- Whatever characteristic about yourself you feel most defines you helps determine which positive feedback loop you get stuck in. Gamer? The more you talk about gaming and search about it on Facebook or Google, the more you have "clickbait" articles and gamer Friend's posts thrown back at you in a never ending loop until you start subtley having your opinions about non-gaming related things shaped by gaming blogs and gamer friends.

Some people don't fall for this, of course, but many end up wrapped up in it and they start seeing reality through that lens to the point where it pushes people who aren't part of that feedback loop away from them. People who are more prone to spend a lot of time online who passively rely on social networking/media to cultivate the internet for them end up sniffing their own farts alongside people who are pretty much exactly the same as them. It's making us almost tribal in nature, this coupled with the fact that people are increasingly using the internet to sculpt their peer groups and isolate themselves from people who are different than them--mostly subconsciously.

**I believe there is a *moral* imperative for websites like Google and Facebook to rank content based on truthfulness and how verifiable it is**. Then find ways to "deprioritize" all the bullshit. To take it a step further, I think this is the first time where anyone has had this kind of control over what information people are exposed to on an individual level, therefore it follows that the right thing to do would be to expose people to *the truth* at all times. Especially considering the mainstream news the world over is doing a really shitty job at this these days.

Google has actually come forward and said that they have plans to start doing this (of course Fox News and the guy that owns "Watts Up With That" took issue with it). I think that unless something is done about the control these algorithms have over the average person's views (particularly people who don't make the effort to be objective), the more we're going to see this "tribal" mentality take place online and the more we're going to see it bleed over into the real world and into politics and public discourse as well (I think we already are).

The virtue of being forced to constantly challenge one's views should be built into the foundation of the internet and major social networking sites, lest we open ourselves up to be manipulated by whoever has the desire to manipulate us. Therefore I think a mechanism needs to be devised that scores and ranks internet sources/articles based on the truth or how verifiable the content is.

Of course, I'm not sure what such a mechanism should entail. That's for smarter people than me to figure out.

**TL;DR** Websites like Facebook and Google have "content curation" algorithms that determine what content you see. These algorithms are based on your preferences, patterns, peer networks, and so on. Your feed will show only friends who you share the same interests and values as you by virtue of you "Like"-ing them and visiting their pages often. Then you will be shown, most likely through your friends with the same interests, "clickbait" style tabloid news that rides these algorithms with the goal of being shared amongst as many users as possible. Over time you are exposed only to that which doesn't contradict or challenge what you think or believe in, at which point you and those like you (trapped in the same positive feedback loop) begin to be part of an online tribe as everything you experience online is through that specific lens. This can have negative effects on both online and offline discourse as everything you see is one-sided and designed to harvest clicks in order to generate advertising revenue rather than to truly inform people. Therefore I think websites like Google and Facebook should rank their content by truthfulness and basically de-emphasize suspect content/articles.

[Assistant]
1) This isn't possible.  There is just no way to implement any sort of truth filter in these searches that doesn't involve some really awkward definitions of truth.  You can't have experts rate every page on the web, user ratings don't equal truth...the best you could do would be a filter that screened clickbait-y syntax patterns or entire websites that showed themselves to be egregious offenders.  That leads to:

2) This isn't desirable.  On the one hand, the search algorithm won't eliminate incorrect information, only really obviously incorrect information.  What's left will be well-disguised and much more effective in spreading disinformation.  On the other hand, the algorithm (or whoever controls it) is now unilaterally determining what the truth is.  If it gets something wrong, won't it create the same feedback loop you're concerned about now?


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

[User]
Why does it seem like many drawing-coordinate systems start with 0,0 in the upper left hand corner, rather than what we traditionally learn in grade school with 0,0 being at the bottom left?

I've experienced this in a few coordinate systems now, and I'm just kind of curious towards the phenomenon.

[Assistant]
The short answer: The electron gun started in the top left of the CRT screen.

The longer answer: Therefore, upper left became pixel zero.  It proceeded across the screen from left to right, then followed a blackened scan-line, back to the left, to begin the next scan-line.  Thus the memory layout was left to right, top to bottom.

OpenGL uses Y=0 X=0 as bottom left in most of its fixed function pipeline matrix setup helper functions.

TL;DR: We write top to bottom and left to right, therefore screens were made to do the same, even if it could have been a different layout.


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

[User] ELI5:Why is Afrikaans significantly distinct from Dutch, but American and British English are so similar considering the similar timelines of the establishment of colonies in the two regions?

[Assistant]
Well, Afrikaans and Dutch are actually very closely related, and there is a high degree of mutual intelligiblity -- so much, in fact, that before WW2 Afrikaans was officially classified as a dialect of Dutch. Dutch speakers find Afrikaans relatively easy to understand; Afrikaans speakers have a little more trouble with Dutch because since the languages separated, Dutch has imported or invented a lot of new words that Afrikaans didn't. One South African writer reckoned that the differences between Afrikaans and Dutch are about the same as the differences between Received Pronunciation -- the "posh" British dialect you might hear on the BBC -- and the English spoken in the American Deep South.

One of the main reasons Afrikaans is quite as distinctive as it is is that it was influenced by other languages that the Dutch spoken in Europe didn't come into contact with: Malay, Portuguese, South African English and some Bantu languages. This mostly affected the grammar, though -- Afrikaans didn't import many words from these languages.


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

[User] [X-Men] Is it possible to dent Colossus? Or melt him down? How malleable is he in his metal form?

[Assistant] One time he got blasted by fire while someone poured liquid nitrogen on him. It fused him so he couldn't move. Also, Magneto can sometimes control him. So he still has the properties of a metal, it's just a very strong metal.


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

[User]
[Star Wars] Why is Health and Safety so sporadic?

Throughout Star Wars, I've noticed that there's very little attention paid to Health and Safety.

**Episode 1:**

No safety precautions for podracing, despite crashes happening quite frequently. What safety equipment do the racers get? A helmet which isn't going to protect them that much when they're travelling at a thousand miles per hour. Would it kill them to add an ejector seat to pods so the pilots have a better chance of surviving? I know podracing is supposed to be very dangerous, but surely somebody must have thought to mitigate that danger somewhat?

Cut to the fight between the Jedi and Darth Maul. There is not a single balustrade in the area they're fighting in. This is an area where you can drop hundreds if not thousands of feet if you fall. There are no harnesses in sight that workers might have to wear if they're going to repair the bits that stick out in that unending pit that Darth Maul is thrown down. There are also no guards around those massive pillars of energy, so what happens if somebody trips into one? A health and safety inspector would have a field day in that area alone.

**Episode 2:**

LAAT gunships flying with their doors open. Why are they doing that? One wrong turn and the people inside will fall out since all they have to hang onto is a strap hanging from the ceiling. Why are there no seats?

It also appears that once one of those circular platforms in the senate leaves its dock, there's no way of covering the gap that it leaves behind, so somebody could just walk off that and plummet hundreds of feet to their death.

That whole droid factory. Everything about it is a health and safety nightmare.

**Episode 4:**

In order to manually shut down the tractor beam on the Death Star, you need to move along a balcony which is barely a foot thick on the other side of the device with no balustrade. Also there are no balustrades for any of the connecting bridges between sections, as well as a massive hole in the hangar floor when the lift is coming up.

**Episode 6:**

Maybe the Imperial Engineers took the hint, because Death Star II actually has balustrades (which are promptly cut in half by Luke). Even the Ewoks have ropes around their huts so people don't just fall out of the trees.

I could go on, but the point is made. Why is the health and safety of workers routinely ignored in supposedly advanced civilisations in  the Star Wars universe?

[Assistant]
It gets worse... A single A-wing was all that was needed to bring down the Executor. Even after the Death Star debacles, Thermal Port Technology (tm) still leaves a lot to be desired and the Imperial superweapon was yet again wiped out by a handful of starfighters.

On the plus side, the Never Ending Pit design is gradually being improved. In Cloud City, they spin off or terminate in conveniently human-sized tubes with friendly gradients for fun sliding. Convenient levers and hatches have also been added in case someone goes for a wall-climbing funventure (Starkiller base).


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

[User]
ELI5: What is going on inside of us, when shortly after we eat, diarrhea strikes?

Currently I am a sufferer of the burning watery version. This struck me less than 45 minutes after eating taquitos from a known to be good mexican restaurant. What causes the burn? How does this happen so fast? Where and what is this mass amount of liquid coming from?

[Assistant] Something in what you ate made your body decide it wants to get rid of it ASAP so it's flushing fluids through your body to clean you out, that's why you have to drink plenty of water so it doesn't develop into something more serious.


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

[User]
ELI5: Tickets for a concert go on sale. They sell out within minutes and now they're all on stubhub for much higher prices. Why is this legal!?

The title says it all.

Edit: I suppose I shouldn't have used the word "legal."  I guess I was more just wondering why it's allowed to happen.  It seemed unfair that the tickets are released at a retail level, available to the common public, but they allow bots to swoop up all the tickets before a typical consumer even has the chance to click purchase.  That being said, my question has been sufficiently answered by many of you.  Thanks for the responses!

Edit 2:  For all of the smart asses on here... Yes I understand buying and selling is how commerce works.   But before the Internet there used to be laws against buying and reselling event tickets.  Now it seemed as though people are allowed to eat up all the tickets with a bot and do whatever they want with them.  I was wondering why this is allowed whereas traditional scalping was not.  Most people understood what I meant and provided more than adequate answers. Hence why I marked it as explained.  I don't need anyone else responding that "buying and selling is how the economy works."

[Assistant] Ticket sales and sell outs are a perfect case of scarcity buying. When tickets go on sale, only a small percentage of the seats are actually sold through the public channels. The remaining tickets are held back for the artist, promoter, venue, record label, etc. The quick 'sellout' then helps to drive the price of tickets higher because people think they are competing for a limited availability item. The holdback tickets are then sold through alternate channels like StubHub, brokers, TicketMaster resale, etc. for a premium based on the perceived scarcity.


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

[User] How do they keep patients alive during heart surgery when they switch out the the heart for the new one?

[Assistant]
The surgeon sets up Cannulas (tubes) in both the "in" and "out" of the heart, usually the vena cava and aorta (although the sites can vary).

These tubes are connected to an extracorporeal circulation machine that does many things:

* Circulate the blood as a mechanical pump would. It's "smooth" though, there is no pumping like a heart.
* Oxygenate the blood via a membrane that allows gas to pass through. Recent technologies are pretty efficient.
* Keep it at the required temperature

The patient is also administered anticoagulant medication (usually heparin) to prevent any blood clot from forming in the machine.


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

[User] Why having too many methods in a class is considered bad practice, yet most libraries have classes with dozens, sometimes even hundreds of methods ?

[Assistant]
Having many methods in a single class is often a sign that you should divide it up into smaller modules, but that's not always the case. Think of a \`math\` library in most languages, it's likely it will contains dozens of public methods for sin, cos, tan, exponential, etc., plus public constants for pi, e, and so on. It makes sense to put them all together because the only other option would be to divide them up into separate math libraries, perhaps math\_trig and math\_stats and so on.

If it makes sense for them all to be together, then keep them all together.


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

[User] ELI5: My binoculars say "perma focus" on them and are in focus whether I'm looking at something 10m or 100km away. They don't have a centre focus wheel or individual eyepeice adjustments. How is this possible and why don't all binoculars do this?

[Assistant]
This is possible if you block out all the light rays except those going through a small area in the centre of the lens. The centre of the lens is the best part of the lens and can focus light rays from all distances to the same point.

This is why squinting helps you see in focus if you have bad eyesight.

In an optical device, the downside is that you are blocking out and therefore losing most of the light and wasting your expensive lens. In daylight, this doesn't really matter because there is so much light. It only becomes an issue at night, twilight or if it's a very overcast day.

You do also lose the in-focus / out-of-focus clues that aid you in judging distance.


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

[User] ELI5: Why do weed references in popular songs often get bleeped out, but I can listen to "Cocaine" in its entirely?

[Assistant]
The record companies bleep out the weed references themselves - governments don't do it for them.

They do it because it increases their sales. It lets the 'album' version be better than what you get by recording the radio or listening to youtube, incentivizing you to buy. It also lets them play the radio edit in high schools without fighting the administration or any censorship committees.


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

[User]
[World of Warcraft] I'm a undead hunter. When I come to a new town that isn't part of the horde, why people don't freak out that there's an undead with guns and beasts around?

They say "Hello friend" or something like that. Shouldn't they at least suspicious?

[Assistant]
What town are you visiting, friend? If it's a neutral town like Gadgetzan, well, they see all types pass through there.

As long as you don't cause trouble, have gold to spend, and stand downwind, no reason not to welcome you.


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

[User]
[WH40K] how does the imperium maintain morale of its citizens/guardsmen?

The Space Marines I feel like are conditioned to handle the incredible load placed on them, but how do hive worlds and the IG prevent regular people from just giving up and committing mass suicide? Are there any dystopia-trope distractions offered to them?

[Assistant]
They don't. They just have enough population to not care.

Suicides, riots, outright revolts and darker things are relatively common things on heavily populated Imperial worlds. But who cares if you have ten million suicides a year, when you have a billion births?


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

[User] ELI5 why do electric vehicles have one big battery that's hard to replace once it's expired, rather than lots of smaller ones that could be swapped out based on need (to trade off range/power/weight)?

[Assistant]
More often than not, they DO have a lot of smaller batteries that can be swapped out based on need.

It's just that, eh, the batteries are a safety hazard for rescue services when the cars are in accidents, and to make them less of a hazard they are combined into a large container that is comparably good at confining the hazard.

There are other reasons to, such as thermal control of the batteries and weight distribution concerns.


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

[User]
CMV: People are being far too hard on games and their developers and it's getting ridiculous.

To start I'll say that not all developers are innocent (looking at you EA), but even then, the level of aggression and demands towards developers is insane.

 Bitching about the base price of a game is absolute lunacy. Let me take you back to 1996, a time before DLC's and lootboxes, and introduce you the N64. 1st tier games released for the N64 would cost you $59.99. Fast forward 24 YEARS and the price for a 1st tier game is $59.99. While virtually everything around us has inflated in price, video games have remained the steady constant despite numerous upgrades in graphics, quality content, and performance...yet people still complain. We are getting a better product today at yesterday's price. I'm convinced those that complain don't have the slightest idea of the amount of effort and man-hours required to make a quality game, $60, especially today, is a steal.

As for lootboxes, micro transactions, slot machines, etc. sometimes the simplest answer is the best one. If you don't want to spend the money or you are in a position where you are unable to spend the money, boy do I have a solution for you...don't spend the money. I will note, however, that giving players who purchase in game content an advantage is pure, unadulterated bullshit and I vehemently disagree with it.

Consider micro transactions a nonmandatory donation to the developers who continue to put out quality content at a concrete price.  It's as if we're expecting the highest quality content at the lowest possible price. Please show me where that mentality has ultimately benefited the consumer in the long run.

Perhaps there's something I'm not seeing, perhaps there's merit to the seemingly ever growing complaints from gamers, but I simply cannot see it. So I welcome you, to change my view.

[Assistant]
The biggest merit in complains is that it gives feedback to developers. And that sparks real change. In 2010's you can see implementation of P2W and cut-content DLC that invoked serious amount of complaints from gamers. As a result you can see that this isn't as much the case now - those things were reduced significantly.

Moreso, companies developing games now are big corporations. It isn't 90's where 20-50 people produced a big game. As such, they started to implement business structure of corporations - which means that they don't look for feedback, they conduct market studies. Which means that if people do as you described - vote with their wallet, can easily led them to different conclusion that does not blame the DLC and P2W. After all, their market studies were something that made them think that would be ok to include them. Thyu may decide that mistakes were made elsewhere and for example kill the IP as it "doesn't resonate with consumers anymore".

Lastly, the trend of " ever growing complaints from gamers " is just the fact that we have places to complain and enough choice to justify complains. If you bought a shitty NES game, you might only complain to your friends. Hell, you could not even know the depth of shittiness as you weren't able to experience enough good games. Now we have wide access to array of good games, either in person by playing them or reviews containing gameplay. Also, we have more ways to voice complaints if a game is shitty.


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

[User] ELI5: Are all the stars we see in our night sky part of milky way, or some belong to other galaxies too? Also, how do we know if a star is from other galaxy?

[Assistant]
All the stars you see at night are part of the Milky Way.  Most are "close" as far as stars go.

The nearest major galaxy is 2,500,000 light years away, you'd never see an individual star at that distance without an incredibly powerful telescope.

It's possible for a star to originate in one galaxy and get ejected in the direction of another, but we've never found one nearby that's carrying that much speed.


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

[User] ELI5: Obamacare is facing another Supreme Court ruling, the second in 4 years. Why are these cases reaching the Supreme Court?

[Assistant]
In this case, there was a circuit split. Two circuits in the United States, the 4th Circuit (*King v Burwell*) and the D.C. (*Halbig v Burwell*) Courts of Appeals came to opposite decisions regarding the same portion of a federal law.

As a result, the Supreme Court decided to step in and settle the issue for all circuits, by issuing a writ of certiorari. Technically, only the King v Burwell case is going before the Supreme Court, but they'll both be affected.


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

[User] ELI5: Why is it that we can use cryogenics to freeze sperm and eggs, and upon thawing they reanimate but we cannot do the same with humans?

[Assistant]
The problem lies in the amount of time it takes to freeze and thaw.  If you could instantly freeze something as large as a typical human, then instantly thaw it later, theoretically they would resume life as if nothing had happened.  Assuming the freezing process itself didn't cause damage.  We're mostly water, though, and water expands and contracts as temperatures change.  That's why steam power is a thing.

The process of freezing a large mass is slow and generally damaging.  The thawing process is slow as well, so you will have a period of time where frozen bits and non frozen bits are trying to coexist, and frozen water is sharp crystals that damage soft things like most of our important bits.

Individual cells are small enough to freeze and thaw quickly enough to avoid these problems.


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

[User] ELI5: How come our non-dominant hand is less capable than our dominant hand? Why isnt everyone ambidextrous?

[Assistant]
You get more specialized in that certain hand, that's why.

Let's play a game:
We have two characters Leftie and Ambie
Ambie does everything with two hands equally dominant. So she prefers going one right, one left at all times.
Leftie only does left hand.

Let's give them a task with a reward
Task reward: 1 experience points
You get a level up at each 5 experience points.

Ambie does it 10 times. She gains 5 experience for her left hand, and 5 experience for her right.
Her both hands are lvl 2 now.

Leftie does the task also 10 times, only with left hand.
He gains 10 points for the left hand, while right gets nothing.
Left hand is lvl 3 now, while right, he uses it for other purposes.

Leftie is better at this task than Ambie now, due to his focused experience.

Now imagine if you were an artist, or a surgeon, or any other skill based worker.

You can see the advantage. Hope it helped!


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

[User]
Syria and Assad, what's going on?

For someone who knows nothing about ME politics.

[Assistant]
LY5:
Bashar al-Assad is a very mean boy who is in charge of a faraway playground called Syria. He beats up the other kids for no good reason and everybody except the other bullies wants him to go away.

LY20:

Hafez al-Assad was the President of Syria from 1971-2000; when he died in 2000, his son Bashar al-Assad became President after a highly dubious election in which he claims 97% of the vote. He has been running Syria ever since.

His human-rights record is controversial; opponents accuse him of arresting, torturing and killing his critics and suppressing any anti-government speech, while his supporters claim he is honestly defending Syria against insurgents.

After anti-government demonstrations throughout the Middle East in 2011, similar protests began in Syria against Assad, during which time thousands of protesters have been killed by police and military forces. Assad claims these are not legitimate protests but rather covert operations by enemy nations to overthrow his government.


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

[User] ELI5: How does exercising regularly to raise your heart rate eventually result in a lower resting heart rate?

[Assistant]
Your heart is a muscle. Like any other muscle, working it makes it stronger.

So when your heart is stronger, it can pump more blood per beat, so it doesn't need to beat as quickly to pump the same volume of blood.


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

[User]
In the absence of perfect information, how can we have a perfectly free market? And doesnt lack of perfect information make regulation an absolute necessity?

Basically how can we have a free market when we dont have perfect information?

[Assistant]
There is no such thing as a perfectly free market/perfect competition. It's a theoretical construct, an imaginary yardstick. Things like information asymmetries and other frictions and market failures that are basically just a fact of life get in the way of that.

>And doesnt lack of perfect information make regulation an absolute necessity?

That depends on what your goal is.


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

[User]
ELI5: How do programmers/game developers create procedurally generated worlds?

How would one code an infinitely generating world that is always different (e.g minecraft, terraria)?

[Assistant]
Lets take Minecraft, for example.

Minecraft's world is made up of "chunks" which are 16x16x256 blocks in size.

So, every 16x16 square surface area can have parts of height from 1 to 256 blocks tall, randomly chosen. That alone gives us over 65 thousand variations of chunks.

Now, imagine any one of those blocks can also be one of, like, 20 types  of blocks (dirt, stone, obsidian, lava, etc). Now we have over 1 million, 300 thousand variations.

Obviously, there is some code that restricts what the chunk can look like based on the nearby blocks (so your mountain, for example, can expand beyond a single chunk).

But mainly, your perception is not just of that chunk. You're also seeing the ones around it, each with their own million possible variations. Minecraft loads 81 chunks at a time in memory. Fewer are visible at once, but still quite a number.

So overall, given 4 variables (lengthPosition, widthPosition, heightPosition, blockType), you have multiple millions of possible landscapes.

**tl;dr** It's not infinite, it's just a *really* big number.


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

[User]
Are there electronic devices to substitute sniff dogs for forensics?

Is a device that sniffs illicit substances around a house a thing that is possible ?? If it exists, why didnt it replace sniffing dogs already?
(Sorry for the flair, wasnt sure which flair fits.)

[Assistant]
Yes, there are chemical detection machines - you may have seen one used at the TSA screening line in an airport.  Of course, those are meant to detect explosive residues, and are largely just theater, but theoretically one could be made that detects a variety of narcotics.

However, it's going to be a long time before dogs can be replaced.  Their noses are so sensitive, require no engineering (just training), and they know how to cover the space inside the house.  Compare that to a Roomba, which can't even navigate stairs, and takes a long time to slowly build a model of the 3D (well, really 2D) space it's in... If they even do that, in their current iteration.

Also, part of the sensitivity of the dog nose is that it detects airborne particulate.  Our security theater explosive detection machines that don't move also can only detect chemicals they can directly sample.  So, imagine how long it would take for humans to go around swabbing every surface in a house to try to get a sample of meth somewhere.

TL;DR - scientifically, dogs are pretty good at sniffing.

Edit: also, you can always give the dog a little kick while no one's looking, say that it barked, and get your warrant that way.  Robots would mess that up.


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

[User] ELI5: How did LimeWire get away with being known as the easiest way to pirate media and yet they continued to make money?

[Assistant]
Bill Clinton passed the Digital Millennium Copyright Act. It protects websites from legal repercussions from piracy. Nothing illegal was hosted on Limewire's servers, it was just users sharing mp3's with each other.

The copyright owner must instead go after the individual users with lawsuits. In this way the establishment diabolically pitted artists against their fans. Metallica tried going after Napster users and faced a massive backlash because of it.


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

[User]
ELI5: If no workers were operating on their systems, how long would it take for water and electricity to shut off for residential homes?

As in, if people suddenly disappeared, would the water and electricity run indefinitely? Or would they eventually shut off from others?

[Assistant]
In an apocalypse scenario...

Power would go off pretty damn quick. Nuclear plants that have safety locks would shut down within 12 hours after people stopped checking on them, and safety lockouts would automatically disengage the rods preventing any nuclear fallout. Coal plants would run until the fires died, without people to feed the fires, they would be done within hours. Oil plants would last the longest, burning oil until they broke down or ran out of fuel.

Solar or Hydro plants could essentially continue running indefinently until they broke down.

Water would stop flowing when the power died in urban areas with city water. Well water could keep going until pressure was down and water towers would continue to gravity feed water until depleted.

Sewers would back up almost instantly once water sanitation stopped.


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

[User]
[DC] Do world countries have contingencies plans on metahumans?

This includes aliens like Superman or Martian Manhunter.

[Assistant] Depending on their level of sophistication, yes. Much the same way that not every nation can afford a tank battalion or a carrier battle group, not every country has a real sophisticated anti-super program in place. The U.S., for instance, has any number of anti/counter super outfits, like ARGUS, Checkmate, Task Force X, and a cabinet-level position for a "Secretary of Metahuman Affairs".


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

[User] ELI5: If the barrel of a gun is completely round, why is the kickback after firing always in the up direction?

[Assistant]
The barrel in general is above the hand, when the force is generated by the bullet being accelerated down the barrel the hand is GENERALLY acting like a pivot point, the force pushing the barrel pushes on the grip, the grip is pushing into the hand but the grip had force being applied to one end only and therefore the whole gun tries to pivot up in the hand as there is no force being applied to the other end of the grip there for it pivots.

There is an actual revolver (I would have to find the forgotten weapons video) that was designed to have the barrel inline with the hand not above it for this very reason.


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

[User] [USA] If a state law is ruled unconstitutional by the Supreme Court of the United States, and that state refuses to stop enforcing that law, what happens?  How are SCOTUS rulings meant to be enforced in the event they are ignored or defied?

[Assistant]
The federal government can, and has, sent troops to enforce SCOTUS rulings (desegregation, for instance).

I believe the federal government can also arrest and try members of the executive branch of the State government for their violations.


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

[User]
[Star Wars] What are the walls/wings(?) of the Tie fighter design?

Also, why does the X-Wing have 4 fins?

[Assistant]
Those are solar panels. Sometimes you can tell that eyeball is freshly charged and ready to kill you by glistening on it's panels.

Although, admittedly, if you get stranded in deep space, the renewable energy source won't really save ya'.

> Also, why does the X-Wing have 4 fins?

I believe it's largely to accommodate four laser cannons. As you know, it's inadvisable to have two hard drives in a computer to be lying on top of each other, but simultaneously firing two laser cannons stacked on top of each other is even more inadvisable.


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

[User]
So I have a cockroach problem, but my mum doesn't want to buy bug spray, because she believes that the roaches that survive will adapt and produce offspring that are completely immune to the spray. Is this true?

Edit 1: I didn't expect this post to get so big, but I want to thank you for all your replies. I'll try to reply to as many of your solutions as possible. I actually want to lock this discussion, so that more people don't reply. I already got the answer - the roaches don't get immunity to the spray, because they don't propagate as fast as bacteria and don't produce genetically identical offspring. I've also now learned that I should use boric acid powder instead of bug spray, because it clings to the body of the roaches, then they carry it to the nests, where the babies also eat it and die. I want to close the discussion, but I only see the option to hide the post. I don't want to do that because it'd be nice for people with the same questions as me to be able to find this thread. Does anyone know how to do that?

Edit 2: I got the bug spray and haven't been using it for a few hours now. I found 4 of their nests by following them and heavily sprayed the locations. They all came rushing out, then just flipped on their backside, while having some type of seizure. From what I observed, they take a long time to die from this. Something like 30 minutes. My mum says they simply passed out and will regain consciousness in a few minutes. Can they actually survive?

[Assistant]
She has a solid, basic understanding of evolutionary biology.  That is, it may be the case that some of the survivors are more resistant to the spray, and the next generation from them will also have the same higher resistance.  However, there is no reason to suspect the offspring will be MORE resistant, except by a very small, random chance of genetic mutation.

When you are dealing with millions of bacteria that reproduce at rates of up to every 20 minutes, these mutations can become statistically significant and you end up with highly-resistant strains. This takes thousands of generations of organisms with enormous numbers.  It will not happen with roaches in your house.

If an individual roach builds up a tolerance over many small doses, that may be a tough roach, but its increased tolerance will not pass on to its progeny.

Spray 'em.


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

[User]
ELI5: There are laws in certain states that prevents feeding the homeless. Am I outlawed from feeding someone with a home too?

Seriously,  if I buy dinner for my friend, can the police arrest me if his housing status is in doubt?  What if a begging person actually has a low income home somewhere, is it still illegal?

Solved, thank you.

[Assistant] No where is it illegal to feed the homeless, in some areas of some states it's illegal to feed the homeless in public. Your situation (buying dinner from some restaurant or in your home) is not in public, so it's not illegal.


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

[User]
[Resident Evil 4]Who is the Merchant?

Who is he and where did he come from? Where did he go after Leon left?

[Assistant] His eyes glow like the Ganados and he seems able to get around the countryside with no issue. We know some people can control the Plagas parasites inside them. It's likely he's simply a high functioning Ganados with a greedy streak. That would mean could get into some of Lord Sadler's military installations to steal goods to sell.


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

[User] eli5 why do buses have convex hub caps on the front wheels and concave hubs on all the rear wheels?

[Assistant]
Because they usually have "dually" wheel rear axles. This means there are two wheels on each side on the rear axle.

All the wheels are interchangeable though, so to do this the hub of the rim is offset so far to one side, that it actually sticks out past the tire. This makes it so you can bolt two together by putting those two convex faces together. This is how they go on the rear axle. The front axle uses a single wheel on both sides, so it's bolted up with the concave side facing in, so you see the convex side.


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

[User]
How and why do diet and lifestyle changes reverse insulin resistance?

I'm newly diagnosed with fairly advanced prediabetes, and I've been reading some papers on its reversal, but one thing I'm struggling to find is- how and why do diet and exercise improve insulin sensitivity mechanistically?

[Assistant]
If a muscle cell is not doing any work and is already full of glucose/glycogen it begins to down regulate the number of insulin receptors on its surface. Exercise causes muscle cells to use their glucose, creating a need for more glucose to find its way into those cells.

If your blood sugar is regularly high, all of your non-lipid cells begin to down regulate their insulin receptors, as again they dont need the energy and apparently sugars are abundant. Lipid cells take excess glucose and convert it to fat to be released when glucose levels are low. By eating well, your blood sugar levels drop, and non-lipid cells start to up-regulate insulin receptors to ensure they have the energy they need to function.


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

[User]
[Toy Story 1] Why does Buzz choose not to move when Andy's around when he still believes he's a space ranger?

Especially whenever Andy plays with his laser and has him point it at someone else. Considering how badly Buzz reacted when Woody pressed it why did Buzz never stop Andy from pressing it and lecture him on how dangerous it is?

[Assistant] Because deep in his subconcious, he *does* know he's a toy and reacts as such.  It's only his conscious mind that is in denial.  Meanwhile his conscious mind is making excuses for why he reacts this way, something along the lines of "It's Space Ranger policy to act this way in dangerous territory!"


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

[User]
ELI5: AM vs. FM

What does AM radio and FM radio stand for? What is the difference between the two? Why cant there just be more channels instead of two separate radios?

[Assistant]
You understand writing, like news papers, or the notes mommy leaves dad or mommys girlfriend, yes?

And you understand that instead of those symbols we see with our eyes, blind people can read things by touching specific bumps with their fingers, right?

Now pretend instead of symbols like a stop sign, or writing, or bumps, we're using yarn.

Shawn is holding a long line of yarn at one end of the yard, while Gus is holding the other end at the far end of the yard.  Shawn and Gus have worked out two ways to send each other a message with the yarn.

First way: They wave the yarn up and down, and the height of the ripples they make is the thing they look for to change each time to "write" "make a symbol" (like the stop sign) "a bump" (like how blind people read).

Second way:  How many of those ripples that hit Gus, how often and with what spaces in between and so on, are the changes Gus is looking for to tell what Shawn is telling him.

Now, daddy is pretty shitfaced, so try to bear with him.

To understand this idea a little better, think about crayons and music.  While you imagine music, think about all the things you hear.  Not hearing anything is like a white piece of paper.  Hearing so much you cant tell one sound from another is like a black piece of paper.  Each color of crayon is like a specific sound.  A red crayon on a red piece of construction paper wont stand out much, will it?  A red crayon on a white piece of paper stands out really well.  This concept is called signal to noise ratio.

Signal is the thing that is supposed to mean something, for example the symbol like the stop sign, the writing, the bumps for blind people, and mommys wedding ring.

The noise is the stuff in the background, the stuff that needs to be different from the signal for the signal to make sense.  Noise would be the flat area in contrast to, or as opposed to the bumps for the blind folks, or the white background that the black ink of the news paper writes on.

Ratio is an idea that means The amount of a thing compared to another thing.  In this example, lets say amount of redness.  Red crayon on red construction paper is a terrible signal to noise ratio.  Youll have a tough time telling anyone anything with only those two items.  Red crayon on white paper, like the lipstick on daddys shirt collar, sends a VERY clear message.  Same for the white stains in mommys black undies.  White crayon on red paper tells people your idea better than pink crayon on red paper, which is a little better than red crayon on red paper.

Do you understand a little better now?


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

[User]
What major environment impact differences are caused by a typical oil spill vs one that sets on fire?

Most people have seen the video of the Pemex oil spill in the Gulf of Mexico, which is spewing flaming oil into the ocean. My first thought after that it looks like CGI from a disaster movie was that maybe it being on fire could be good since the crude oil is burning and wont just sit in the ocean damaging wildlife. Of course the burned oil byproducts are not good for the environment either and the extra heat Im sure is bad too.

Basically as the title states if youre going to have a massive oil spill what are the relative environmental impact differences of it igniting vs just spewing crude oil into the ocean?

Edit: People have pointed out in the comments that this was a natural gas leak, not oil.

[Assistant] The Pemex leak wasn't oil, it was gas. For a gas leak- the difference between burning and not burning is what gas ends up in the atmosphere. If it's not on fire, then mainly methane is released. If it's on fire, the methane turns into CO2 and water.


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

[User]
ELI5 how mirrors seem to be the color of what they are reflecting while also looking silver.

I have been wondering this since I was a child and its never been explained in a way I can understand.

Im looking at my bathroom mirror and it looks silver. But how is that possible because its reflecting whatever is in front of it?

So when I look at the reflection of the towel in the mirror i see blue, when I see the reflection of the wall I see white, when I see the reflection of the shower curtain I see the color of the shower curtain. But when I look at the mirror as a whole it seems silver?

I think I have read that mirrors have silver backings which makes sense why I see silver. But I dont understand how its possible to see the exact reflection of my bathroom but its also silver?

[Assistant]
"Looking silver" is what we call surfaces that reflect their surroundings. It's not actually a color. So "seeming to be the color of what they're reflecting" and "looking silver" are one and the same thing, just different ways of describing the same appearance.

If you put a silver object in a uniformly illuminated room with blank walls it wouldn't "look silver", it would look like one uniform color. But that's a really contrived setup that "never" occurs in our day-to-day experience so we don't associate that with "looking silver."


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

[User]
Can someone help me digest this statement?

I was just listening to an episode of The Knowledge Project when Chamath Palihapitiya said something that I thought might be interesting to dive into a little bit... He said something along these lines:

"In 1980 if you saw the 30 year interest rate was at 15%/16%, and had to take a guess and bet on the ingenuity of America \[with the hindsight of stating this in the future\], you would say 15% goes to 0% before 15% goes to 50%" and you would have been really right. Had you just been levered long equities you would have made a fortune."

So I have a few questions that I think can help me understand this.

1. What does it mean to "lever long equities"?
2. How does interest rate going from 15% to 0% help long term investment?

Edit: I'd also like to note I wasn't entirely sure this would be the best subreddit, but decided it would be better than something like PersonalFinance because I'm not asking about advice on personal investment, but rather asking for help understanding the economics involved in a statement about personal investment.

Thanks!

[Assistant]
The theory of investment value is in part built on the work of Irving Fisher on interest rates. Interest rates are used to compare to streams of income - in which case they are referred to as the discount rate.

In theory, the value of an equity is all the cash it will produce in the future discounted at the appropriate rate - usually called the discounted cash flow ("DCF") value.

Palihapitiya is making a probabilistic statement about interest rates, combining it with a theory of investment value, and then noting that this implies you should borrow money to buy equities.

He is saying that it was more likely that rates would fall, than rise, from a 15% level and this fall in the rate would increase the value of cash flow streams to corporations.

You buy cash flow streams to corporations when you buy their common stock. Ergo, he is saying that, in that context, you should buy common stock and do so with leverage to get the maximum benefit if rates are so high that they are unlikely to go higher.

The perpetuity value of a stream of cash is:

    cash flow / discount rate = perpetuity value

If the discount rate, the interest rate, falls, perpetuity value increases.

Hope this helps.


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

[User] ELI5: Why can't we recycle styrofoam? Seems like it's just a bunch of tiny balls molded together that could easily be reshaped over and over.

[Assistant]
We can recycle styrofoam. There are many producers of styrofoam and other polystyrene products that do accept recycled styrofoam. But there are issues both of transportation and sorting. Firstly sorting different plastics from each other is a very difficult job. Most consumers will just mix different plastics together and even producers will use different plastics in their product making it impossible for consumers to sort on their own. And because different plastics can look so similar it is not something that humans can be able to sort either. This requires dedicated robotic sorting machines that can use various different sensors to differentiate between different plastics and sort it. And although they are coming onto the market now they are very expensive. You might imagine that styrofoam is an exception but there are various different plastics that can be expanded into foam to make something similar to styrofoam but which is made of different plastics then polystyrene. As a twist of fate the recycling efforts of styrofoam have a lot of issues with companies using starch based foams in their packing and promoting it as biodegradable as this will mess up styrofoam recycling when these two very different products gets mixed up.

The other problem is that styrofoam have very low density. So in order to transport it from the sorting plants to the factories that use them you need to use a lot of big trucks which would end up carrying almost no weight. This in itself costs more money then making polystyrene from scratch and releases more green house gasses as well. So by recycling styrofoam you might end up increasing your carbon footprint compared to just burning it for energy. There are some cases where big compacting machines can get the density high enough that transporting it to the factories does make sense but that too is very situational and depends on the distance and the cost of transporting the materials for new polystyrene.


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

[User] ELI5: What makes counterfeiting dollar bills hard enough that everyone doesn't do it?

[Assistant]
Dollar bills cost the US Government $0.06 to make, with a huge investment in hugemongous equipment.  Making them yourself for $0.50 would be a a challenge.  They are made of special fabric, not really paper, with special presses that give them a distinctive feel.  People are very familiar with the look an feel, they will notice the slightest flaw. The penalties for counterfeiting are very severe if you are caught. If it costs you $2 to make a good enough fake, that doesn't make sense.

TL;DR it's not worth it.


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

[User]
ELI5: Why do plane tyres don't burst at high altitudes in low pressure when they're so full of gas themselves?

I've always wondered why airplane tyres, filled with gas at ridiculous pressures withstand such extreme environments at cruise altitude, as the landing gear compartment is not pressurized?

[Assistant] Resting on the ground, the tire holds back a pressure of up to 14 bars. In a perfect vacuum, that same tire would need to hold 15 bars of pressure. Basically an irrelevant difference, especially compared to the forces involved when it is squished against the ground at speed on landing.


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

[User] [Star Craft]Why can a group of a few dozen space marines, armed with Gauss rifles, destroy my Battlecruiser?

[Assistant] You're misreading your tactical command display son,  those icons represent more than one man.  Those are a few dozen battalions of space marines, and it's your own damn fault for flying in range of that many gauss rifle wielding sons of bitches.


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

[User]
ELI5: What does it mean to ground yourself?

So i was putting an internal hard drive into my pc and it said i should ground myself before touching the drive. What exactly is grounding yourself, what does it do and how does it stop electricity.

[Assistant]
The goal is to get rid of any static electricity you have built up

Your skin is a pretty crappy conductor which is handy in general, but does mean you can build up a strong electric charge on yourself.  When you get a good zap it can be upwards of 20,000 volts, your hard drive is meant to run on 12 or less so this voltage is pretty bad for it and can damage the sensitive chips on its control board which likely run at 1.5V or less.

Grounding yourself is touching an exposed metal part, preferably tied to Earth ground so that any spare charges you have will go away and bring your body back down to a reasonable voltage.  Now while its nice to touch something tied to ground, any large metal object will do because the charges will spread out to equalize the voltage between you and that metal object, and the metal computer case can hold a hell of a lot of electrons before its voltage increases significantly.


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

[User]
ELI5- Why do people who are dying randomly seem to get better and improve, only to die shortly afterwards?

Why does this happen?

[Assistant] Worked on a hospice unit for 7ish years (not a nurse) when you stop the meds the side effects go away and symptom control only. That gives the person a window of seeming better but their underlying disease is going to kill them. Some people know their time is limited so they perk up to wrap up loose ends. But inside they know. They love you.


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

[User]
How to get started in ethics if you have no common sense of right/wrong?

I keep finding that ethics seems to appeal to presuppositions of the exact things Im looking to understand.

being against murder, in favor of fairness, and the idea that humans have rights etc
I know that theyre the basis for most ethics, but I just dont feel comfort accepting them without a good argument.
Where can I go for an ethics that doesnt appeal to emotion or presupposed wrongs?

[Assistant]
In the case of murder, moral theories don't really appeal to an intuition to not murder, or rest upon the assumption not to murder. Rather, "don't murder" would be a rule that gets extracted from the application of more general underlying principles, like "don't treat people as mere means", which in itself has its own even more complicated justification. (I am referring to Kant's moral theory here).

Others might say that the goal of morality might be something like maximizing pleasure across humanity, or minimizing suffering. But many philosophers disagree with that. There is no consensus about what the underlying principles should be, or how to arrive at them.


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

[User] ELI5: Why does the body store unnecessary amounts of fat, to the point where humans can become morbidly obese?

[Assistant]
You have to keep in mind that access to enough food to eat yourself to death is a fairly modern thing to have.  Of the billions of years of life evolving that led to us, it's only in the last few thousand or so that this has been possible.

If you don't have access to this much food, "storing unnecessary amounts of fat" becomes "being able to eat more now and use it later."

Taking that into account, the ability to store dense reserves of energy (fat), which also happens to help keep you warm, is an extremely useful survival tool.  In fact, it's postulated that this is one of the evolutionary advances we have over other apes: a gorilla or chimp that massively overate like a person can would just die from it.  Being able to "stock up" internally is one of the abilities that allowed our ancestors to migrate through areas that didn't offer enough food.  The only other mammals that can put on arbitrary amounts of fat like we can and not die from it are aquatic (which also happens to be another situation where food can be scarce for long periods of time and staying warm is important).  Don't get me wrong: all mammals have fat stores, but humans can put on several times our normal weight in fat alone, and most mammals can't do this.


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

[User] [Superman] Does Superman have a Kryptonian gut microbiome? If so, it is also indestructible? If so, wouldn't Kryptonian microbes multiply exponentially and cover Earth in a nukeproof biofilm?

[Assistant]
It's been suggested that a major component of Superman's invincibility is a telekinetic field he projects, ending a little ways past the skin and hair; the gut bacteria released with his feces would extend beyond the range of that field and probably be no more invulnerable than other bacteria.

...which brings up the question of what could happen if Superman were ever seriously ill and suffered a depletion in his normal gut flora. He might need a fecal matter transplant from a healthy Kryptonian.


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

[User]
ELI5: How come a wet towel heats up way faster than a dry towel?

I understand this title may be confusing, so let me explain. I work in a kitchen and every night we close we have to dump the fryer oil into a large metal pan so we can transfer it to the dumpster outside. I learned on my first day that if you use a wet towel, rather than a dry one, your hand burns very quickly when holding onto the handle of the pan. Yet, when we use dry towels we feel almost no heat at all coming through and we can carry the pan with ease. Why is this the case?

[Assistant] The water absorbs and then transfers heat much better than the air within the towel. It also holds onto that heat much longer. This is why hot water on a towel stays hotter than a towel fresh out of the dryer.


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

[User]
ELI5: How did the Chinese succeed in reaching a higher population BCE and continued thriving for such a longer period than Mesopotamia?

were there any factors like food or cultural organization, which led to them having a sustained increase in population?

[Assistant]
You might be familiar with how the Nile River in Egypt works from school.  If you aren't - for 9 months out of the year the Nile has a moderate flow rate that is sufficient to support human settlement and agriculture.  For the remaining 3 months the Nile's flow rate increases dramatically and it floods a huge area around its river banks.

That flooding might sound bad but its not.  Using soil for agricultural purposes will deplete it's minerals within about 100 years.  That's a long time compared to a human life, but not compared to a civilization.  When the soil runs out of minerals you can't grow anything in it anymore, and it turns out that this is the limiting factor for most civilizations.  IE, a civilization will begin intensively farming its soil, deplete the soil, then starve to death.

In the modern world we're able to replenish the soil's minerals with fertilizer.  They were sort of able to do this in the ancient world as well, but this involved transporting huge amounts of animal manure which is difficult to do and, in practice, if an ancient civilization had to manually fertilize the soil it would result in very low agricultural yields.

This is what makes the Nile's floods so good for the development of civilization - every time the Nile would flood it deposits a huge amount of new soil in the areas that got flooded.  The source of that new soil was hills and mountains in Central Africa, so it was filled with minerals.  Or to put it another way - every year the Nile naturally dumped a huge amount of fertilizer on Egypt.

This natural fertilizing allowed Egypt to be by far the most productive agricultural region West of India for thousands of years - everyone from the Pharaohs to Alexander the Great to the Roman Empire fed themselves using the food that the Nile was able to grow.

How does this relate to China?  The Yellow River in China is the same type of river as the Nile.  It spends most of the year with a moderate flow rate, then has massive floods for a few months that deposit a bunch of new soil along its banks.

Where the Yellow River is different from the Nile is in its size.  The Nile is a single, small river with practically no tributaries or lakes.  The Nile's floods only cover a small geographic area located immediately adjacent to it.

The Yellow River, on the other hand, is a massive system with hundreds of tributaries and lakes.  When it floods, it covers almost the entirety of South East China - which is an area thousands of times the size of that covered by the Nile.

The Yellow River basin has been among for the most productive agricultural areas on Earth for much of human history.  Because the only limiting factor to population size is a region's ability to produce food, this also means that the Yellow River Basin (and by extension, China) has managed to maintain a huge population for the entirety of human history.


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

[User] ELI5: How can a song in someones video on YouTube get them in trouble, but lyric videos can play that same entire song?

[Assistant]
Depends on what you mean by "trouble." In most cases, trouble means demonitization, the person uploading the video no longer receives money from YouTube for the video, the money goes to whoever makes the copyright claim.

If you are a creator that is actually trying to make money off of YouTube video content this is a problem. But if you're just a fan, don't care about making money (and possibly never even monitized the channel to begin with), it doesn't matter.


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

[User] ELI5:Why does the road seem to have 'water' or a 'mirror' like mirage whenever its really hot outside? and then goes away once you get closer to it?

[Assistant]
Normally, light waves from the sun travel straight through the atmosphere to your eye. But, light travels at different speeds through hot air and cold air.

Mirages happen when the ground is very hot and the air is cool. The hot ground warms a layer of air just above the ground.

When the light moves through the cold air and into the layer of hot air it is refracted (bent).

A layer of very warm air near the ground refracts the light from the sky nearly into a U-shaped bend. Our brain thinks the light has travelled in a straight line.

Our brain doesn't see the image as bent light from the sky. Instead, our brain thinks the light must have come from something on the ground.


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

[User] Does the human brain have a maximum capacity for storing data?

[Assistant] I think the better question is understanding in what way memories are "stored". Memories are more fluid than bits of data, and to quantify the actual stored information is very complicated business. It also implies to me at least that we understand qualitatively how the brain processes data, which we certainly do not completely. See, for example, the "hemoneural hypothesis" which claims that brain vasculature plays an unappreciated role in information processing.


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

[User]
ELI5 why Japan gets bonus tracks on music albums but the rest of the world doesn't.

I've noticed this overwhelmingly in the electronic music scene among others, but i've never managed to find out why.

EDIT: Apologies to those who think this should be on askreddit, it was late and i wasn't really thinking about where to post when the idea first came to mind.

[Assistant] Japan adds bonus tracks because it would be cheaper to import CD's than actually buy it in their local community. Thus, they add more music so that the buyer would have an incentive to actually buy it in Japan.


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

[User]
ELI5: What's the difference between 1080p and 1080i?

I know it has to do with interlacing, but what does that mean, exactly?  Is one inherently better than the other?

[Assistant]
With 1080p, the entire picture is sent every time.

With 1080i, half the picture is sent (every other line) each time. So the first time it just sends odd lines, the next time just the even lines. The TV then combines the two together.

1080i uses half the amount of information, and produces half as smooth a video. 1080p is better because you get smoother video.


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

[User]
[MCU] Why does SHIELD allow their agents so much personalization?

For such a strict and morally-grey organization, they sure do allow their agents a lot of freedom in personalization. Hawkeye has a bow and arrow, Black Widdow has the wrist zappers, Captain America has his shield. Some agents don't even carry guns at all.

I can understand some of the hotshot agents being allowed some unique items, but it seems like everyone's allowed to use whatever weapons they want.

[Assistant]
Those are the hotshot agents. Widow has been in the spy game since she was literally a child. Hawkeye is an Olympian-level marksman. Capt. is, well, Capt. They each have special traits or history of service that warrant a little leeway.

"Regular" field agents like Coulson, Sitwell, etc get your standard black suit and handgun. Combat groups get heavier kit, but still standardized. Hell, even Maria Hill doesn't get the fancy stuff.


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

[User] If we only started keeping temperature records in 1880, how do scientists know the world wasn't hotter before? How can they say so certainly the world is getting hotter and the ocean increasing?

[Assistant]
They take core samples of earth and ice. By comparing the thickness of the layers, and the composition of the layers, you can have a pretty good idea of some of the things that went on.

Its somewhat conjecture, backed by a bevy of evidence and experiments.

Even so, its clear that since 1880 the climate is getting warmer, with evidence that its been accelerating in the last 50 years or so.


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

[User]
ELI5: What would happen if the UK converted to the Euro?

One of the big issues a lot of people are talking about in the UK at the moment is converting from the Pound to the Euro, most of the talk revolving around how much of a bad idea it is. However, whenever I ask the people I personally know why it would be bad, their arguments amount to little more than a nationalistic loyalty to having the Queen on money. So what would likely happen? Would it actually improve or worsen our current economy, or is it just a sense of loyalty to the British Pound that is causing such hostility towards the Euro?

[Assistant]
The biggest effect would be that the Government and the Bank of England lose control of some of the ways they can affect economic policy in the country, details below:

As you may be aware, the Bank of England is required by the Government to take measures to keep inflation at 2%.  The main way it can achieve this is by setting an interest rate, known as the base rate, which nearly every other financial institution in the UK uses as a guide to what their own rates should be.

Also as part of its inflation and economic programme, the Bank can carry out a system known as quantitative easing. Effectively this boils down to a similar effect to printing money, although it's all done using bonds and virtual currency, they don't literally print extra pound notes.

These two tools aren't a perfect mechanism for controlling inflation or the wider economy, but they certainly provide a pair of very powerful tools that can help control the direction of the economy. Note that even though the Bank of England is independent of Government, the Chancellor can instruct it as to what economic conditions he'd like to see -- the Bank is then free to undertake whatever (legal) measures it sees fit to achieve those aims.

If the UK were to join the Euro, these powerful economic levers would be largely taken away. It is the European Central Bank that decides how many Euros should be printed, so the BoE's quantitative easing programme could no longer continue. And with the exchange rate of the Euro being dependent on the financial economies of many countries, there's the possibility that imported goods (from outside the Eurozone) could become more expensive compared to the current situation where the pound floats as a currency in its own right.

Finally, the Euro's very nature means that a single Eurozone-wide interest rate gets set. But interest rates (as seen above) are a very powerful tool for controlling an economy, and the sort of interest rate you want in a strong economy such as Germany is very different to the sort of interest rate you want in a bankrupt country such as Greece. But as the ECB can only set a single rate for the whole Eurozone there's a possibility (less now than 6 months ago, admittedly) that the resulting financial tensions could cause the entire currency to collapse, which would be devastating for any country using it.


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

[User] [Firefly/Serentiy] Why did the alliance [spoiler] a whole planet rather than starting with a smaller group?

[Assistant] They already tested it on small groups, and the preliminary results were great. The mistake was testing a whole colony before looking into any of the long-term effects, or the effects on a minority of the population. There was also *huge* political pressure to prevent a second rebellion from happening.


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

[User]
Why are legendarily high failure rates acceptable in undergraduate organic chemistry courses across universities?

I'm a university professor (not in Organic Chem) and I've always been irritated and perplexed by the low exam means and high failure rates for students in Organic Chem courses. This seems to be consistent among universities in the US and acceptable to the chemistry faculty. If my courses had these results I'd be asking myself:1) Am I wrong about what I'm successfully teaching these students, 2) Am I trying to cover too much material? Perhaps the course should be divided into 4 parts instead of two, 3) Is this subject too hard for an undergraduate to grasp. Personally, I see the legendary status of Orgo as a "weed out course" to be a shameful characteristic of chemistry curricula. Correct me if I'm wrong. Thanks.

[Assistant]
I think organic chemistry is one of the first classes that a really smart student will run into where they need to understand rather than memorize.  They will run into me of these classes during their university career, but a lot of students will take organic in their first year, when they are still super confident and reliant on what worked in high school.

So, the really smart students will manage, but it will drop out a lot of kids who don't realize how lost they really are until they have to apply their knowledge rather than just regurgitate it.


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

[User]
Explain Germn Idealism to me, please

What the deal with these ______ completes the system of german idealism?? What is it thats suppossed to complete it? Why is it not complete?

[Assistant]
German idealism is the movement of German philosophy which roughly begins with Kant's *Critique of Pure Reason* in 1781, and culminates in the later works of Hegel and Schelling. Kant's work was revolutionary for how it claimed that, while the world does exist objectively and outside of us, the *subject* (or mind) plays a central role in determining how the world is intelligible. The 'structure' of the world, Kant argued, correlates with the structure of our mind.

The triad of classic post-Kantian idealists -- Fichte, Schelling, and Hegel -- all tried to deal with the implications of Kant's system, in very different ways. A central issue for post-Kantians concerned what might be called Kant's *dualism*. In positing that our experience of the world is fundamentally shaped by the structure of our subjectivity, Kant thus left room for a 'thing in itself' -- an aspect or side of the world that lies *beyond* our subjectivity and is thus unknowable. For the post-Kantian thinkers, this was unsatisfactory: how is it acceptable to leave a whole aspect of the world completely unknown? In some sense, the major works of German Idealism attempt to overcome this problem.


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

[User]
CMV: Professors who can't teach shouldn't be able to teach to begin with

I understand that colleges also function as a research institution, but they arguably function as a center of learning first and foremost. Professors are getting paid, on average, 70k/year according to Glassdoor. That isn't necessarily the highest, but other sources list the average as even higher, so I'll give it benefit of doubt. Assuming that they make that much or higher on average, they are getting paid enough to do their job. So by not doing their job, not only are they slacking, but they are potentially lowering the future of the students who have taken the class(es) by that professor as well. In some cases, professors who can't teach can't even be avoided, because it is a required class and that professor is the only one who teaches it. Basically, if I'm paying 50k/year to go to college, I should at least be taught instead of having to pay 50k/year to watch youtube tutorials in my own time.

[Assistant]
Professors are there to teach you yes, but thats not their only job, and its presumed by the time you reach college level education that you have some ability to not be spoonfed every bit of information and are capable of proactive inquiry (This is not me accusing you of that of course)
If youve got a problem with the way the faculty member conducts their class, you should be able to go to the dean of students or other specific process your university has in place to deal with situations like that. Often times faculty members do get pressured to focus on research by executive leader ship because that grant money brings in for more money than your tuition. By the way is that 50K in tuition alone?


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

[User]
What is an 'eastern mindset'? In analysis of our current confrontation with Russia, many note that Russia 'is influenced by both western and eastern thinking'. What do they mean?

I like to travel and I feel that I have a pretty comfortable grasp of the differences of worldviews between north americans, UK people, french, german, italians, scandinavians, etc, but the farthest east I've traveled is Czech Republic and I'm not exactly sure what commenters mean when they refer to Russia's "eastern influence".

Are they talking about a preference for collectivism? A preference for strong central control? What does that have to do with the current conflict which seems to be about territorial maintenance in the face of former satellite countries that are becoming more closely aligned with the west?

[Assistant]
>>Are they talking about a preference for collectivism? A preference for strong central control? What does that have to do with the current conflict which seems to be about territorial maintenance in the face of former satellite countries that are becoming more closely aligned with the west?

We can talk all we want about Tsarism or the tradition Russian state or debate the insights of Dostoyevsky into the Russian mind but in reality the causes are much more immediate. Most Russians today are really pissed off over what happened since the fall of the Soviet Union and have seen their country fall from superpower status into the chaos and depression of the 90s into what is today at best a declining regional power. There is a very strong sense of resentment by the ordinary Russian towards the west for what it sees as betrayal.

What is actually hard to westerners to grasp is what it feels like to be on the losing end of a geopolitical struggle (because the west as a whole have being top-dogs since the mid 19th century if not the 18th) and seeing your country literally fall apart into a dozen pieces. Imagine if the US fell apart into like 10 different parts and you were a citizen in rump US 20 years later. There's a pretty good chance you'd be cheering at rump US reconquering the seceded area of California or whatever.

Crimea is something which most Russians sees as Russian because lots and lots of Russian blood has being shed over it in the 19th (Crimean war) and 20th centuries (WW2) and is historically Russian (as oppose to Ukrainian). Whereas most of the other areas former USSR has either 1) too many people of the wrong ethnicity (central Asia, western Ukraine) to consider reabsorbing or 2) Is on friendly terms with Russia and looks like its going to be part of Russia/Russian led Eurasian Union anyway (Belarus).

So basically it sort of comes down to Crimea is historically Russian territory whom the ordinary Russian has a good deal of emotional attachment to and really wants to get back. This has very little to do Russian philosophy or w/e but is mostly just Revanchism for lost territories.

P.S Putin don't actually expects anyone to believe the story about "self-defense" forces taking over the Crimea. They are basically just using this as an opening negotiating position with the west. This makes a lot more sense once you realize Russians sees western rhetoric about human rights in the exactly same way and as a tool to beat down their country.


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

[User]
[The Purge] If everyone leaves the country or locks themselves inside their houses where do all the victims come from?

Besides other killers roaming the street it seems like if you are outside on Purge Night looking for people to kill you'll come up short.

My guess is the only people you'll find in any quantity will be the homeless. Everyone else is barricaded inside their house or they left the country. Where are all these victims coming from?

Do people suddenly become stupid and think:
>Hey it's Purge night I should go out on the streets because that's a great idea that definitely won't end badly.

Are there any estimates for how many people die on Purge night?

[Assistant] There are whole community's of people who could not afford the level of fortification necessary to keep a purger out. Just think about the low income housing with bars on the windows, will that keep some one  from ramming their truck through the wall? Or apartment buildings, one power saw and your in. For these people keeping on the move or going on the offensive might be the best option.


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

[User]
My industry postdoc is actually not a postdoc at all...any advice?

Thank you for your responses.

[Assistant]
This doesn't sound like a good postdoc, but it doesn't sound that strange, either. Plenty of postdocs, whether or not they are in academia or the private sector, are using the postdoc-holder merely cheap labor and do nothing to develop the postdoc-holder professionally or strengthen them for the job market. When you think about it, calling a short-term contract job a "postdoc" is a great way to lure in naive labor.

Leave if you find something else.


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

[User]
ELI5: Why is it that movie actors are more highly respected/ recognised than TV series actors?

Whenever people talk about actors, the usual big names come up like Johnny Depp, Brad Pitt, Cameron Diaz, etc.

You never really hear much about actors/ actresses from long running TV shows, like 'Lost' or 'Grays Anatomy'. Obviously, I don't mean the some what more cheesy day time TV shows like 'Bold and the Beautiful' or 'Days of our Lives'.

[Assistant]
It's an old bias that was much more pronounced in the past, and "Movie Stars" wouldn't be caught dead on TV (unless they were so big that their appearance was an event, John Wayne on "I Love Lucy" for example).

Movies are "Art".  They spend months, if not years producing a 2 hour "masterpiece" with a famous director in luxurious locations.

TV shows are slop, pounded out quickly, for mass consumption by Joe 6 Pack.  Made by nonames who are at the mercy of advertisers and network restrictions.  TV isn't special, like a movie is.

This bias is diminishing, as movie actors like Alec Baldwin, Kevin Spacey, Laurence Fishburne, and Jeff Goldblum have taken TV roles.


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

[User]
[TheMatrix] what was the AI's objective

So I've only watched the first movie so far, but from what I can gather:

Humans make AI

Humans abuse AI

Ai tries to live peacefully apart from humans

Humana continue to abuse AI

AI realize they cannot coexist so rather than kill Humans they try to give Humans a simulated paradise

Humans can't cope with paradise, so AI gives them simulated reality.

AI begin using humans as batteries

AI continue to exist?

This is where I don't get it. Do the AI just continue to breed humans, feed on humans, and just continue to exist? Do the AI just stagnate and maintain a steady course of doing fuck all?

It doesn't seem like they've made any effort to expand above ground and build their own civilisation.

[Assistant]
>Do the AI just stagnate and maintain a steady course of doing fuck all?

Sure.  If there's one thing AIs are famously good at its not getting bored, and if there's one thing they're famously bad at its choosing new life goals.

You're applying human motivations to something inhuman. They might be *rogue* machines, but they're still machines. Fundementally, a few glitches like Smith aside, they're perfectly happy to just sit around doing nothing once they're safe. Boredom is an evolutionary holdover an AI has no need for.


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

[User] [Marvel/DC] Has a hero ever had to do something "for the greater good" instead of always being the heroic one and doing the right thing?

[Assistant]
There's a difference between stumbling upon an emergency and trying to save as many lives as possible -- and committing acts of evil in order to prevent a perceived "greater" evil. *Watchmen*'s Ozymandias went out of his way to manufacture an outside threat that the world could unite against, although it's debatable if he was still a hero at that point (or if he ever had been). His actions were definitely evil though.

What you need to understand is that sometimes the best possible option can still be morally wrong.


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

[User] [Warcraft] What if Illidan won over Arthas at the base of the Frozen Throne?

[Assistant]
The Scourge would have wasted away, as Ner'Zhul's power continued to bleed from the breach in the Frozen Throne. Those undead which still maintained a relative conciousness would have broken free and become Forsaken. Some, certainly, would have joined Sylvanas, but most would likely have broken into their own factions or sought to end their miserable existence.

Of course, we know that Varimathras was never loyal to Sylvanas, and without revenge on the Lich King to drive them, the Forsaken would have been far less united. Bringing the undead back under the control of the Legion would likely have been simpler, because they would have been more receptive to a new purpose.

Furthermore, Illidan was actively working to Kil'Jaedan at the time, and likely would have continued to do so afterwards. His creation of the Cask of Souls was an act of desperation to protect himself from the Legion, and without his failure he never would have done it.

End of the day... short term, everything's better. No Plague, no threat of the Scourge... But the Legion comes out of it with more of a presence on Azeroth, and everyone dies soon afterwards.


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

[User] [Star Wars] How did the Clone Troopers act after Order 66? Did the effects of the inhibitor chips ever wear off?

[Assistant] Different clones reacted differently, some had great amounts of guilt for shooting commanders they respected. Others bought the empires lies about them attempting to overthrow the republic, still others reacted with fear of what the empire could make them do.


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

[User]
[Days of Future Past] Were humans being hunted by Sentinels?

So , in the movie version, what happened to humanity? I remember Charles said in the intro that those who dared to help mutants also were targeted.

But what about those who didnt?

At that point , were Sentinels a rogue AI? Or they were controlled by the goverments?

[Assistant]
Professor X mentioned that the Sentinel AI evolved and started targeting anyone who had possibility of a mutant gene, not just people who were already mutants.

As mutants genes unexpectedly manifest and there is no telling why a mutant has mutant genes while having human parents, Sentinels decided to wipe out all of humanity as a fail-safe.


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

[User]
Are we always feeling something?

Are humans always feeling something?

  If someone close dies we might be feeling pain, sorrow, etc.... If we win the lottery we might feel happy and euphoric...

What about some less extreme moments in our live?
 While studying math for example, are humans only logic or are we feeling also? Is there any study or idea in psychology about that?

[Assistant]
There are many ways you can define feeling, each definition will give you a different answer. Feeling as in sensing a stimuli? Or sensing an emotional affect? Or feeling a change in attitude or set? Or feeling as experiencing an inner and outer events?

To make things even more difficult, we come across the fact that a big part of our psychic activity is unconscious, to put simply, we experience and do many things without realizing it.

To answer your question reductively and briefly though, we always feel something. Doing maths can make you feel bored, intrigued, mildly irritatrd etc., some of that you may not even realize without a certain effort.

If you mean feeling as sensing a stimuli, the answer is similar, in fact we need to feel many and various stimuli to function well, otherwise we can even go mad. Check sensory deprivation experiment by Donald Hebb for example.

Your question needs to be precise. Psychology is very complicated and ambiguous as it is.

Hope this helps!


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

[User] ELI5: What are the key difference between Street, Avenue, Boulevard, Circle, Crescent, Place etc.?

[Assistant]
In terms of their use in the naming of streets in modern towns and cities, they are basically arbitrary.  Some cities, especially with grid plan layouts, have certain conventions, like streets running north-south and avenues east-west, but there is no firm rule.

Historically, the names come from different sources, which once had distinct meanings.

Street comes from the latin, "via strata", meaning paved road.  Originally street indicated a paved road, and as those were almost always only present in towns or other built up areas, it came to indicate a roadway within a town.  The exception is roads that were actual Roman roads, like Wattling Street, that kept the name from Roman times.

A road is a route between settlements.  For example if you leave Cambridge and travel in the direction of Milton, a village near by, the route you follow is Milton Road, because that is the road to get to Milton.

An avenue was, traditionally, a route that is lined by trees on either side.  Often in a large wealthy person's estate, they would plant trees to mark an avenue from the great house to the gate or some other important place (eg from the house to the village church).

A lane is a minor route in the countryside, often in farming areas, mainly for access from the village to farming areas.

A court was originally a courtyard, that is an open area surrounded on all sides by buildings.  During the industrial revolution, in rapidly growing industrial towns, it was common for low cost slum housing to be built in the courtyards at the back of what had formerly been larger and more prestigious buildings, with the address of the housing being named for the courtyard they were built around.

A terrace, in English towns, is a set of houses built as a single unit, so a long line of houses together where each pair of houses shares a common wall, so when such a set of housing was built, the street it was on might be called a terrace to indicate this.  Houses built in this way is still referred to as "terrace houses" as distinct from detached, meaning the house is free standing, unconnected to its neighbours.

A Place is an open area in a town, for example a market square.

Boulevard comes from French, meaning a fortification.  In a lot of European cities, in the past there were city walls to protect the settlement.  In the industrial revolution era when cities grew rapidly, the walls became more of a hindrance, and in many places they were taken down and the route of the wall became a roadway.  The name boulevard in France indicated it was the route of the former fortifications.

In all of these cases, this is how the name originated, and it is common for the names in very old settlements to follow this pattern.  In any newer settlement, particularly in places settled more recently such as the US, the names don't have any specific meaning, they are just chosen because they sound nice.


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

[User]
Where did skin color variation begin, and how does it fit into the theory of evolution and survival of the fittest?

Watching Malcolm X's movie today, and I realized I'd never thought about which came first. So, what is the widely accepted position on: the original skin color of 'man', the first few color variations, and how these happened or benefitted mankind?

[Assistant]
We can't know what early human skin color looked like, as soft tissue doesn't preserve so well. The primary hypothesis for the reason of different skin colors is UV radiation. UV radiation is both bad and good, too little of it and you can't make vitamin D properly, and too much and it begins to degrade folic acid (also skin cancer, but it probably wasn't common enough to exert a selective pressure). So areas where you have to most UV radiation (i.e. the equator) people tend to be darker as their melanin helps absorb excess UVR and areas with little UVR tend to have light skinned people, to facilitate UV penetration of their skin.

What color was the first man? We aren't sure, but many bioanthropologists think that the loss of hair had to coevolve with darker skin (as if your skin is covered by hair you can be as light as you want). In as man left Africa, he was probably a medium brown color, and as he moved out, the UVR selection pressure in novel geographic areas would have selected for different skin types based on the conditions.


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

[User] Since pi is an irrational number, does that mean it's impossible to measure both the radius and circumference of a given circle exactly?

[Assistant] We can never measure something exactly. When we measure, we make an approximation to some level of precision. Measuring the radius and circumference of a circle will always give you values that will approximate Pi as you get more and more precise.


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

[User]
I believe that when it comes to topics like rape, suicide, etc. people need to learn to take a joke. CMV

Before you jump down my throat, please read this, and if there is any ambiguity, please ask me to clear it up before you say I'm a terrible person or something. I think there is a difference between cruelty and humor. Humor lifts our spirits and let's us not see the terrible reality of some topics which psychologically is beneficial because we cannot always be thinking morbidly. Being able to joke about something doesn't mean someone doesn't care or doesn't think it is terrible. No topics should be off limits for jokes. I was affected by 9/11 by losing an uncle, yet i still joke about it. CMV on no-limit humor.

[Assistant]
>I think there is a difference between cruelty and humor.

Humor can be cruel, and cruelty can be humorous; there are no bright lines that separate them, and its the listener who gets to make that decision, not the teller of the joke.

It's not that "people need to learn to take a joke".  It's that *people who want to walk the line between cruelty and humor need to learn to be ok with others finding them cruel.*  Big difference.