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

[User]
Who has the advantage in a quiz where two people have to guess a number (e.g. an amount or a prize). The first guesser or the second?

I am a radio host and sometimes conduct radio quizzes. As a tiebreaker between two contestants, I use a "guess how many"-question, like "How much money did the local government spend on traffic in 2015?" The first contestant gives an answer. The second one then answers. What is most fair?
A: That the first one guess a number, and the second guess a number?
B: The first one guess a number, and the second says higher og lower?

My thinking is: In scenario B, number 2 has a 50/50 chance, but I am not sure if number 1 has the same 50/50 chance, because the success of his opponent is down to 50/50?

Another question: Is the fairness affected by the nature of the question, i.e. the difference between a random number and an actual number that might be, but unlikely is known by one of the contestants?

[Assistant]
If both players are rational, then there should be no difference between your two modes of play (second player guesses or second player says higher/lower). Suppose player A says 50, and player B believes the answer is 60. It will always be strictly better for him to guess the minimal increment higher than the answer of A, say 51, rather than his actual guess. This way, if the true answer turns out to be 53, he would still win where this wouldn't have been the case had he answered his actual guess of 60.

So if your aim is to benefit the smarter player, you should keep the second guess. If your aim is to equalize the field, then go for higher/lower.

As for the second part of the quesiton: Even though the precise answer (the amount of money spent by the local gov't on traffic, for example) is likely to be unknown to players, smart players may be able to come up with a reasonably good order-of-magnitude estimate. This means that if a weak player is to guess first, there is a good chance for the smarter second player to score a nearly guaranteed win. For example if the first player guesses $100, the second player should immediately recognize this as far too low and guess "higher" (or $101). In reverse, if the smarter player goes first and produces a reasonable guess, then the second player might as well flip a coin to determine his guess of higher or lower.

When using random numbers, a similar effect is present, with the difference that there is a clear optimal strategy for both players. The first player should guess the average between the lower and upper limit of the random number (assuming symmetric distribution) and the second player can guess either higher or lower, it makes no difference. If the smarter player goes first, both players will always have a 50% chance of winning (assuming the higher/lower system is used), since the first player will guess the middle value. If the weaker player goes first, he may not guess the middle value, which would give an immediate advantage to the second player.

So to conclude: The best solution depends on what you want. Should it effectively boil down to a coinflip? Or should there be an advantage for smarter players? Using a random number has the best chance of ending up with 50/50 odds for both players since the optimal strategy is relatively easy to see, but it may become boring when the first player always guesses the middle value and the second player has no influence once this is done. Using an actual question is definitely more interesting, but the player with more knowledge / better estimation skills will benefit in this case, but primarily if he can play second.


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

[User] ELI5: If mosquito's are attracted to light. Why don't they all fly to the sun and leave us alone?

[Assistant]
Because that's not what's really going on. Insects use the sun or moon to navigate -- keep the light in the same relative position and they'll keep going in the same direction.

This works with the sun or moon because their relative position isn't going to change very much as the insects fly. But insects can be confused by man-made light sources, and these do change position as the insect flies past them.

So... insect flies past a street light and the position changes. Insect adjusts course to keep the light in the same relative position. As this process repeats, the insect winds up spiraling inward toward the light until, finally, boom -- they wind up flying into it.

They aren't attracted to light and, in fact, that would be a bad thing for a nocturnal predator to do. They're just confused because street lights and the like don't behave like the sun or moon.


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

[User] ELI5: Why are UltraWide monitors 21:9 and not 7:3?

[Assistant]
First, it's not actually 21:9; it's 64:27.  21:9 is just a close approximation that can be easily compared to 16:9.

As to why it's 64:27, it's because monitors were initially in 4:3 ratio.  Wide screen squared the ratio (4:3  4:3) to 16:9 and ultrawide screen cubes it (4:3  4:3  4:3) to 64:27.


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

[User]
ELI5: What is "20/20 vision" and why do they call it that?

What is it that makes a prescription 20/25? Why do we use the term 20/20 to describe perfect vision?

Edit: Thank you so much to everyone who answered this! Especially to Teotwawki69, excellent answer.

[Assistant]
The top number is an arbitrary designation to indicate what people with "normal" vision can see at 20 feet, and is fixed. The bottom number indicates your vision. So, if you have 20/20 vision, you can see at 20 feet what people with normal vision can. 20/40 means you can see at 20 feet what people with normal vision can see at 40 feet, etc.

This is why a designation like 20/400 generally means legally blind. However, it can rarely go the other way, and there are people with 20/15 vision or better, which means they can see at 20 feet what people with normal vision can see clearly at 20 feet, etc.


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

[User] Why does a ball bounce higher the more air pressure it has?

[Assistant]
Distortion of the material of the surface of the ball absorbs energy as it bends and rebounds. Higher pressure reduces the movement of the surface and allows more energy to go into the bounce.

There are additional gains depending on the material of the ball, for example if the material is somewhat elastic, then pre-stressing or pre-stretching the material keeps the tension forces closer to the impact area, which more efficiently converts the momentum.


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

[User]
[ELI5] Why are Human babies so helpless?

Of all the species of life on Earth, human babies take the most time to reach adulthood and proper functioning.

Why is this so?

[Assistant]
Because we needed to stand up.

That meant the hole that the baby slips through is restricted in size, forcing human babies to be born much earlier and thus with much more limited capabilities.

Animals on the other hand allow their youth to develop a lot further in the womb, and then plop out fairly functional.

The downside for us is that babies need a lot more care, luckily we developed a lot mentally to get very good at that.


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

[User]
[General] How can vampires get erections if they don't have a pulse (i.e. no blood flow to the genitals)?

Vampires are always sexual beings and are always having sex with humans and each other in almost every fictional franchise. I'm curious as to how this is explained.

[Assistant] Vampires can control every aspect of their bodies. While they are technically dead, they imitate a pulse to fool investigation, extend/retract fangs, have superhuman abilities, and can sometimes even completely change their appearance outright. It's not hard to believe that they could somehow get it up without needing blood, considering everything else seems to work without it.


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

[User]
How to know the difference between existentialists

I believe that there are many philosophers that are considered as existentialists.

Kierkegaard, Nietzsche, Jaspers, Camus, Sartre, Beauvoir, Merleau-Ponty, Heidegger (I think he is not, but our school's textbook says so), etc.

I heard that even Dostoevsky and Kafka were kind of existentialist.

I know that they are divided into big two category of christian existentialists, and atheistic existentialists.

But some says Nietzsche is nihilist or something, Camus is absurdist, and, yeah.

Since I am not even an undergraduate but a highschool student, I don't have opportunities to get deeply about philosophy.

I read some books such as The Myth of Sisyphus, The stranger, The Plague (Camus), Being and Nothingness, La nause (Sartre) to try to understand them, but I ended up hardly undertanding them.

I want to know differences between absurdism, nihilism, existentialism, and differences of those philosophers.

Thank you!

[Assistant]
>	But some says Nietzsche is nihilist or something,

Only people who are wrong about Nietzsche say this (such people are common, particularly on the internet).*

>	I want to know differences between absurdism, nihilism, existentialism, and differences of those philosophers.

The typical introduction that is recommended is Sarah Bakewells *At the Existentialist Caf.*

*EDIT: the point below about active vs passive nihilism, etc., is well-taken, but at this level youd do best to just not associate Nietzsches position(s) with contemporary things that come to mind when one hears nihilism.


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

[User]
Question about Thor's fighting style.

If no one in the universe, not even the hulk, can pick up Thor's hammer when it is left on the ground, why not use that fact for a tactical advantage? Why not, if there is a monstrously gigantic villain, do they not knock him to the ground and then just place the hammer on top of him while they knock him senseless?

[Assistant]
Then what?

Is the chest of the star-consumer beast of ak'thraben to be the resting place of Mjolnir for all eternity?  And what might He Who Laughs Thunder use to crush the spines of OTHER adversaries in the meantime?

Not to mention, a vast majority of Almighty Thor's epic battles happen in the air, or space, or some other such place.  And even upon the ground - Mjolnir may be indestructible and unmovable, but the ground is hardly so!  Many a foe could simply tunnel downward to escape this childish "trap."  While none but Glorious Thor Thundergod can move Mjolnir once placed, it does not create infinite downward force - otherwise, during the Thunder God's battle with the Hulk upon the S.H.I.E.L.D. helicarrier, The Hammer of The Gods would have broken through the hull and plummeted to (the center of) the Earth as soon as the Bringer of Storms put it down!


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

[User]
I think it should be compulsory to donate organs, CMV

I think it should be compulsory to donate organs. Burying or cremating people and not putting there organs to any use is a huge waste, CMV.

[Assistant]
I don't see this as possible as it is against several religions to desecrate the body after death. To put this situation into effect would be to tell those people their views don't matter.

A better option would be to enroll everyone automatically unless they opt out of it. That way you'd get a lot of the people who don't care and just don't bother to check the box.


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

[User] ELI5: What is Entropy and why can't it be decreased?

[Assistant]
Ok imagine you have made a sandcastle. It's perfect, it has turrets and windows and looks fucking awesome. But the wind is strong and eventually your sandcastle that you've spent ages building gets blown into the wind. Well that is entropy.

You start off with something really ordered and neat (the sandcastle) and the wind comes along and makes your lovely neat castle into a disorganised pile of sand again. So if you imagine the start of the universe it was in it's most highly ordered state (the sandcastle) then ever since that point time (the wind) has come along to make it more disorganised.

As to why it can't be decreased. Well that's a bit more of a tricky explanation. But essentially. Everything in the universe uses energy, and then re emits that energy. But the energy it puts out is less organised than the one it put in. If it didn't and the energy stayed just as organised. We wouldn't exist.


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

[User] ELI5: What's that feeling of death in your chest that comes from eating thick foods like peanut butter too quickly?

[Assistant]
That terrible feeling you're describing is your esophageal wall being pushed further than it's supposed to flex.

This is because the food you're eating and the dry state of your esophagus means the food can't slide against the esophageal wall well enough to conform to your esophagus' shape.

Chew your food better, drink with your meals and take smaller bites to avoid this awful feeling.


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

[User]
[Star Trek] why do the starships engage in combat from such close ranges?

I understand the federation is on peacekeeping mission and normally don't expect combat but I imagine it would pop up.

[Assistant]
Most starfaring races in contact with the Federation tend to use phasers or similar for their primary weapons.  These are unguided weapons, and given that they're essentially particle streams, they propagate somewhat slower than the speed of light.
What this means is that you have to lead your target, not shooting at where he is, but where he will be when the beam has traveled the required distance.  The problem there is that as range increases, the target has more time to change course and not be where you predicted him to be when you fired the weapon.
With the kind of acceleration possible with inertial dampers, and a computer capable of carrying out a number of 'random walk' style maneuvers, it becomes very difficult to hit a ship with a phaser at medium to long range.


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

[User] ELI5: How does activated charcoal help against ingested poison?

[Assistant] Activated charcoal is charcoal that have gone through a process forming lots of extremely tiny structures in it. These structures will be able to trap bigger molecules like poisons but let smaller molecules like water and ions alone. So if you eat activated charcoal you will essentially slow down your digestion process as it will bind to any of the larger molecules and therefore slow down the absorption of poison into your body.


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

[User]
[Marvel] Who is the most technically proficient fighter in the Marvel universe ?

who, in your opinion, is the most technically proficient fighter in the Marvel universe ?

[Assistant]
Deadpool. He's totally unpredictable, due to his insanity, and as a result was able to defeat Taskmaster. For those that don't know, Taskmaster could copy anyone's fighting style due to an amazing photo-reflexive memory.

The whole not-dying, expert at several martial arts, amazing marksman and swordsman also helps.


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

[User]
ELI5: Why are TV shows making less episodes now per season than they did in the past? Wouldn't they make more money with more episodes?

A TV show on average would produce 25+ episodes a season. Now we'd be lucky to get 12.

[Assistant]
Because a lot of the time some shows don't have enough content per season to stretch to that amount of time. When they are able to compact it into less episodes, more resources can be put into those episodes. This leads to a better show in general. Better shows bring more viewers which can attract advertising that can make you more money.

For example, compare Game of Thrones to the Flash. Both are good shows. The flash while good ends up stretching its content into "fluff" episodes which aren't too good. In fact you only have to watch about 7 - 8 of the 22 or so episodes of the first season to get the meaningful parts of the story. With Game of Thrones however, almost every part of every episode is meaningful. Each episode is about 50 or so minutes long and there is only 10 episodes a season..

Which one makes more money?


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

[User]
Are there any mathematical operations that don't have an inverse?

Earlier today I was thinking about how I tend to check division using multiplication, subtraction using addition etc.

This got me thinking about whether there were any operations that didn't have an inverse.

I couldn't think of any off the top of my head, and the only things I know about that I thought could be options were some kind of mappings to the complex plane or w plane or something like that.

[Assistant]
Sure. What does an inverse g for a function f: X -> Y mean? The function f(x) turns an element x from the set X to an element y from the set Y, and the inverse function g when applied to y will return x. However, this means that there must be at most one x which corresponds to each y. If f(1) and f(2) all return 3, then what will g(3) return?

A common example of a non-invertible function is f(x)=x^2 from R to [0, infinity). Both f(2) and f(-2) return 4. Note that the same function from [0, infinity) to [0, infinity) is invertible.

The horizontal line test is sufficient to test some functions for invertibility.


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

[User]
Problems with reading Kant

I just started reading Critique of Pure Reason and I'm starting to realize that it might be an impossible task unless I get some help. The book is unbelievably dense and dry and I just cant follow what he's saying. Has anyone paraphrased these demonic texts so I can read that instead.

[Assistant]
No. But you can read secondary scholarship. A good first introduction to Kant is Guyer's *Kant*, and good sources on the *Critique of Pure Reason* are Guyer's (ed.) *Cambridge Companion to the Critique of Pure Reason* and Allison's *Kant's Transcendental Idealism*.

Often, people reading Kant's theoretical philosophy will begin with his *Prolegomena to Any Future Metaphysics* instead, as they often find it more accessible.


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

[User] ELI5: Why can you not see through fog when it's ahead of you but you can once you're in it?

[Assistant] You have a bunch of particles in the fog blocking your vision. Lets say there are particles directly in front of you blocking ten percent of your field of view and theyre evenly distributed as small bits in the air. And then another. And five feet away, theres some more particles blocking another ten percent of your vision. Thats twenty percent. The farther away you go, the more particles are there getting in between you and what you want to see.


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

[User] [Star Wars] So were all familiar with the risks of being a high-ranking officer in the Imperial Navy (1 strike rule). What are the benefits?

[Assistant]
Have you ever wanted to point at a cloud of glowing rocks, floating in the bleak void of space, and say to the girl (or guy, or twi'lek) you're trying to pick up: "That used to be a planet until it pissed me off"?

Seriously, that uniform will get you laid faster than you can say "you rebel scum".


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

[User] [Star Wars] When Jedi swing a light Saber around, why does the Saber always swing as if there is mass to the light beam, causing the centrifugal force to be focused solely on the center of the beam and not the handle?

[Assistant] The trick with a saber blade is that it doesn't completely lack mass/resistance, because it is not just a laser beam or a shaft of light. The saber beam is basically a plasma chainsaw, flowing in a very tight, very fast arc from the emitter out to the tip and back again, which appears to be just a solid bar to the naked eye. This momentum has an impact on the balance/feel of the saber in operation.


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

[User]
I think that not all cultures are equal. Some are definitely superior to others. CMV.

I read a recent TIL article about how certain aboriginal tribes will form holes in the bases of boys' penises when they come of age. The hole is kept open with a splinter.

There's just no way that all cultures are equal, or worth the same. Western culture tends to emphasize reason over superstition, human rights and equality, and technological progress. Western culture has given us beautiful art like the Mona Lisa, and beautiful literature like Paradise Lost. The Renaissance, the Enlightenment, democracy, etc. are all products of Western culture.

As opposed to Aboriginal culture, which has given us holes in the bases of penises.

[Assistant]
What criteria are you using to judge which are superior? Whatever your criteria are, they're influenced by your culture. If you live in a culture that values reason, you're going to see cultures that emphasize reason as the most superior cultures. If you're in a culture that values freedom, or happiness, or knowledge, or strength, or any number of other qualities, you're going to prefer the cultures have those. If that sounds circular, it's because it is. How can we demonstrate that your values are the ones we should be judging superiority with?

Where one person see a culture that causes needless harm to each other, they may see a demonstration of strong men who can withstand pain. Where one person sees art, they may see a waste of time and effort.


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

[User]
[Witcher] What are varying religions stance on the afterlife given that ghost really exist?

I know the common folk can be very dismissive and uninformed on the strange and supernatural, but many believe in gods in some form or another. There are accounts from lowborn to dukes and even kings of ghosts encounters. I'm not talking about just  Noonwraiths and Barghests; people have encountered fully aware ghosts that recall their past and speak in the present to the living.

Side question: Which is the most popular religion? Or one with beliefs that most align with the world?

[Assistant]
The most popular human religion in the Novigrad and Temaria seem to be the Cult of Melitele, Cult of the Eternal Fire, and the Prophet Lebioda Cult (which has merged with the Eternal Fire cult in the North). These religions don't seem to touch much on the afterlife and instead provide instructions for living a good life.

As you leave the city, more local religions appear. Most seem to be centered around local supernatural phenomenon or some sort of magical being making mischief. And, like the city religions, most concern themselves with the living and rarely the afterlife.

In fact, human spirits seem to rest eternally with there remains and only return to the living world when they are disturbed or have some unfinished business.


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

[User] Why does Amazon pay 0 taxes?

[Assistant]
Two main reasons (1) depreciation, and (2) loss carry-forward:

(1) If you invest in an asset, say you buy a forklift, the value of the forklift that is lost can be deducted from taxes each year. Say your forklift is worth $10,000, but next year it's worth $9,000 because it got older. This is $1000 of "depreciation expense." You haven't actually lost any money, but the tax code gives you a break for investing, so if you made $100,000 and have $1000 depreciation, you are taxed like you made $99,000, even though your cash flow is $100,000.

(2) If you're a business who ran at a loss of $10 for 10 years, this is $100 of losses that you as a business can carry forward. This means that say after the 10 years of losing $10 per year, you start to make $10/year in profit. Well let's say for 10 years you make $10 in profit. This means each year you're taxed as is you made $0 for ten years because you have $100 worth of loss you can deduct from future earnings.


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

[User]
[MCU] How do the species who've never heard of Thanos or Infinity Stones interpret the effects of the Snap?

As far as millions of species know, they were just going about their day when suddenly half their civilization turned to dust. How do they explain this? How do they react? And how will they react if, presumably, the effects are reversed after Endgame? (I'm assuming, for this thread, that it's not undone by time travel, but simply reversed with the power of the gauntlet so that everybody sees their neighbors turn to dust and, a year later, suddenly return).

[Assistant]
Even for those that know of Thanos the effects of the snap are still going to beyond comprehension for everyone besides the avengers. Even the Wakandans were completely baffled and they were at ground zero of the invasion.

Humans will most likely attribute it to God and the rapture or something equivalent. Im guessing most alien species will have some similar notions and if they didnt, they may develop them now.


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

[User]
ELI5: Ignoring any legal issues, how effective would going to a veterinarian for medical care be?

Let's say that the town vet is fully stocked with electricity and supplies post-apocalypse. How good of a medical clinic would it be?

[Assistant] Depends on what your issue is. For injuries and other immediate care issues, a vet would be helpful as the general first aid procedures would be more or less the same. For surgeries and such, it would be a little trickier but the vet might be able to adjust the drugs for human use. Long term care or more subtle problems, a vet wouldn't be able to help you as much.


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

[User]
[MCU] Why doesn't Tony Stark build Iron Man suits for Hawkeye, Black Widow, or even Captain America?

Edit: Awesome answers, folks. I'm still not convinced about Hawkeye, but I'm willing to concede that it's probably not a great idea for Cap and Black Widow.

Also, I did tag this as Marvel Cinematic Universe (that's what MCU stands for, right?), but I'd love to hear if/how this question may have been addressed in the comics as well.

[Assistant] They all kinda have their own thing and really its also just Tony's narcissism, he is the only one good enough, and capable, to operate an iron man suit effectively.  He didn't even wanna give his best friend Rhodey one.  Rhodes took a suit against Tony's will and ended up proving he was proficient in its use so Tony thought alright thats cool.


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

[User] ELI5 How do in-car audio systems avoid feedback when using speakerphones?

[Assistant]
Fun fact, car audio is actually really complicated when you start adding features like that.

First off, feedback only happens when the speaker is playing back the same signal that the microphone picks up. So if you're talking on speaker phone with someone who is on handset, no feedback will happen. Your voice will not come through the speakers and be picked up.

So the only case where feedback can occur is when you're on speakerphone and the other end is also on speakerphone. And luckily, feedback only happens when there is little to no delay at all between the systems... in this case the shitty-ness of cellular networks is an advantage, there is always a non negligible delay between transmitter and receiver. So the feedback you experience is an echo.

So the way you get rid of feedback has to do with getting rid of echoes. The logical and most significant way to reduce these echoes is by controlling the direction of the microphone and speakers; so long as the mic and speakers do not overlap in their radiation fields, there will be no feedback. To do this, there are simple designs (directional mics are easy to make). There are also complex designs where the speakers and mics are actually arrays of mics/speakers, controlling the delay and mixing between them will allow you to form "beams" where audio is picked up or transmitted.

Another nice thing about echoes is that you can make some assumptions about them. An echo by definition is a delayed copy of something that has already happened... so if you record what comes through the mic, and listen to what comes through the speakers and check against recent things coming through the mic, you can remove those copies. Boom, no echoes or feedback. Again, the inherent delay between systems is your friend here. But actually getting that to work is not trivial.


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

[User]
(Lord of the Rings) What if the One Ring somehow found its way to Valinor?

Can the Valar destroy it, or does it have to be sent back to Middle Earth and cast into Mount Doom?

[Assistant] The Valar, especially Aul, could destroy it. The reason for their non-intervention in Middle Earth is because of the massive carnage that took place in the last war of the First Age (they literally sunk and destroyed parts of the world), so the only reason they have for not destroying the ring is on principle. That is, they don't want the inhabitants of Middle Earth to rely on them.


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

[User]
Why do cats frequently have white paws?

I've had several cats, and I just noticed that a lot of them have had white paws and / or a white chest. I was wondering if there is a reason for this particular color pattern, or if it's just how the genes happen to work out.

[Assistant]
In most cases the coat of a cat is determined by alleles of the cats agouti gene. a lot of it is breeding preference since people seem to prefer cats with white paws, but for bi-color cats there are essentially 5 alleles a cat could posses the combination of which results in 10 possible coats ranging from completely colored to completely white. of those 10, 8 result in cat who has at least 1 paw colored white, 6 with all paws while. So statistically it is more likely for a cat to have white paws. this is because the alleles that cause white spotting are dominant in cats.

on an interesting side not some cats--like Siamese cats--display the opposite color phenomenon. their paws are almost always black. this is because of a breed-wide mutation in their pigment-forming gene which causes it to be temperature-sensitive. it fails to function at higher temperature around the body, but works at cooler temperatures on the legs and tail. If you were a very cruel owner and shaved a patch out of your Siamese cat's back and then strapped an ice-pack to the bald portion the new fur would grow back black instead of white.


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

[User]
Why don't spacecraft burst into flames? (Thermodynamics Question)

In a thermodynamics class, I learned about enthalpy and how it is a measure of the total energy of the system. It also allows us to measure a quantity known as specific heat, where specific heat refers to the amount of energy required to raise 1kg of a material 1 deg C.

Here's where I'm confused:

If you do work on a system, you are adding energy to that system. So in order to get a satellite into geosynchronous orbit, an equivalent amount of work must be done in order to increase the satellites kinetic energy (bringing it up to orbital velocity) and its potential energy (bringing it up to orbital altitude). These two energies combined, should amount to many, many kiloJoules of work and energy transferred to the satellite.

Let's take a 2000 kg satellite made entirely of aluminum at geosynchronous orbit as an example:

m = 2000kg
distance from earth (r) = 42156 km (from wolframalpha.com)
orbital speed (v) = 11067 km/hr (from wolframalpha.com)
Sp. Heat of Aluminum: 0.902 J/(g*C)

The satellites PE (mgh) = 826260000 kJ
satellite KE (1/2mv^2 ) = 9450500 kJ
Sp. heat for 2000 kg Al: 1804 kJ/C

Which means it requires 1804 kJ of energy to raise the entire mass of satellite 1 degree Celsius. OK...KE+PE = 835710500 kJ...

which means at geosynchronous orbit, the satellite should be at a scorching 463,250 degrees C greater than its temperature at 0 m/s on the surface of the Earth.

Obviously satellites don't burst into flames/melt during ascent, so what am I doing wrong here?

[Assistant]
The Energy is being converted into Kinetic Energy rather than Thermal Energy.

Instead of all of the particles being given random motion by the energy, they are all accelerated in the same direction so relative to the spacecraft, the particles are all moving randomly in roughly the same way as they were before.


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

[User]
[Star Wars] Are the clones virgins?

So I know this is kinda a weird post but it kinda hit and I've been really wondering about it, are the clones virgins? They spend like the first 20 or so years on Kamino where it's JUST them and the long neck people. So while they were going through puberty did they ever do it with basically themself. I remember in one episode in the clone wars, it was basically the prologue to the bad batch, and in this one scene a clone in the background was talking about this girl and then another clone says something like "Oh shut it, you never even met a girl." So it really makes you question their sexual experiences. I know this is REALLY weird but it's interesting to think about. Any theories or anything like that would be great!

[Assistant]
To be fair, we don't actually know that it's *just* the clones and Kaminoans on Kamino for the whole 20 years. We only see one facility, after all. Considering that Kaminoans are known as "those cloners", it's entirely possible that there are, shall we say, *more* clones out and about and available for, shall we say, all sorts of social engagements.

And, get right down to it, we've got very little evidence that the long-necked people don't get down with their products, now and then.


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

[User]
ELI5: How do they synchronize a fast paced multiplayer game?

If I shoot at a moving target, due to lag there will be different perceptions on whether I hit him.  How is this determined?

[Assistant]
Former game dev here,

This is actually a really interesting problem to solve. The easiest way to do it is to have the server be the authority. The console is just the video terminal, displaying the state of the game as the server dictates it is. When you shoot, that happens on the server, and you simply display the results.

Most games are some variation of this. Where things get interesting is that video games are rather predictive in their displays to account for lag. Ever get stuck running forward in WoW because of a dropped connection? Your inputs go to the server and you display the server response, with the connection dropped, that cycle is broken, and you only see the prediction animation until you get a new connection, then the world jaunts to the latest server state.

And how do FPS games do this so fast? Most bullet physics are "ray casts". The game draws a straight line and checks to see if it collides with a target. It's an instant hit, it's cheap to compute, and fast. Games with bullet travel account for time and will draw an arch. It's more expensive and depends on some predictive modeling. Projectiles are actual physical models in the game and run normal collision routines as your avatar bumping into a wall...

---

On this subject, physics and animation are HARD. You have an object with a velocity, and you have gaps in time because you need to render frames. What if a billiard ball is moving so fast toward a wall that it bumps off and moves in a different direction between frames? One moment you saw this thing moving toward the wall, the next moment it's moving away in a different direction; it magically transported!

When performing the physics calculations, we have to conceptually draw the path of all the objects and ask who is colliding first, and is it visible to a player? If a billiard ball collides with the wall, you HAVE TO SHOW the collision. Your mind needs to register the billiard ball hit the wall and bounced off, or the world won't make any sense.

You may be trying to render frames at a regular 1/60 second interval, but this collision happened between frames, so your timing gets skewed! You end up rendering a frame that happened at 1/58 second! If this happens once or twice, no big deal, and you can compensate in the next frame by rendering 1/62 of a second later. But if this happens frequently, the passage of time and reality skews.

This is why billiard ball games are some of the hardest video games to make and among the most under appreciated.


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

[User]
[General Sci-fi] Does a ship moving at faster than light speeds still act as a solid object?

I ask because if it did and it hit photons already travelling at 'c', then wouldn't it either tear holes through the ship when the photons can't speed up or break reality when they did?

[Assistant]
A ship moving at FTL speed is outside of physics. Thus, it's pointless to ask for answers in conventional physics. Whatever physics you make up has to account in some way for combining traditional physics and your FTL mechanics. In those combining laws you can make up whatever interaction you want.

It's like asking "What's `1/0 + 5`?" `1/0` is not a number; you can't apply addition to it. In the same sense, `v > c` is not (our) physics.


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

[User]
Why are long songs "Album Only" on iTunes, Amazon, etc?

What purpose does the "Album Only" function serve?

[Assistant] Well especially with older albums like 2112 by Rush for example, the song 2112 literally took up half the album. Apple/Amazon doesn't like the fact that you just bought essentially half an album for 99c. Therefore you can only get the song with the whole album. Misc. legal crap might have something to do with it as well.


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

[User]
[Star Wars] What was the state of the Rebellion at the beginning of RotJ? When did the Rebellion become strong enough to contest the Empire openly?

When did the Rebellion go from scrappy underdogs doing pirate style hit and run attacks and relying on stealth as their greatest protection to being a convention army that would eventually control the galaxy as the New Republic?

[Assistant]
The Rebel Alliance was never strong enough to challenge the Empire directly in conventional military action.  They were always the underdogs fighting a guerilla type action, up to and including the defeat of the Emperor and the destruction of the second Death Star.

For that matter, the New Republic wouldn't have been able to either.  They had nowhere near the military might that the Empire did, because they didn't want or need it.  The Empire's military fractured and broke on its own.  Nobody ever needed to defeat them in a conventional war.


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

[User]
CMV: Exams should be open book/notes.

As an engineering student I find this to be very crucial in learning. Memorizing the material for an exam is not a good way in learning the material whereas having an open book exam makes learning the materials much easier.

 All exams should be open resources. It increases note taking skills that are actually used in life and the work field and decrease exam stress. It's not fair to automatically assume that all students can retain a mass amount of information.

Exams should be applicable based and not a memory test. You retain more information by actually doing research and learning the materials than cramping X amount of information then pouring it out onto a test and forget what you learned as soon as you turn it in.

The whole point is to learn the materials, not just memorize information that you will forget. Not everyone can retain information well so by using resources given to you/using outside resources you gain a better understanding/different view of the material which will help you solve a problem that you don't know the answer to.

Edit: for anyone wondering, I am studying electrical engineering in robotics and mechatronics.

[Assistant]
Depends on the type of exams and subject.

If a subject doesnt give you the time to refer to a notebook when you really need to use it in real life (for a job like lawyer, for example), the exam should be more strict.

But if its about creative thinking and the use of skills rather than just memorizing raw concepts, yes, then the student should be able to refer to notes and other resources.


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

[User] Is Tetrahydrocannabinol (THC) an alcohol?

[Assistant]
When people refer to "alcohol", they could mean 3 things:

1. Ethanol, grain alcohol, or alcoholic drinks

2. Simple aliphatic alcohols like methanol, ethanol, isopropanol, t-butanol, et cetera.

3. Any compound with an -OH group

In the strictly technical sense (3) yes, THC is an alcohol, but not in either of the more common senses (1&2). Any organic compound that has an -OH group could be called an alcohol. Looking up the structure, THC a phenolic alcohol, which means that -OH has different properties than an aliphatic alcohol, but either way, the technical answer to your question is yes.

Is it useful to classify it that way? Probably not. There are many other compounds that also would qualify as alcohols by the same metric, including sugar (sucrose, fructose), DNA, bisphenol A, capsaicin, salicylic acid, etc... Calling THC an alcohol doesn't really tell you much useful information other than "it has an OH group somewhere"


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

[User]
[Stargate]Why did the Ori not also invade the Pegasus Galaxy during their Crusade?

The Ori never invaded the Pegasus Galaxy even though there was a sizable population of Humans there as well.  Did they actually fear going up against the Wraith?

[Assistant] The most important objective of the Milky Way invasion was to kill all the Ancients. Pegasus would come after that. Also, even for the Ori, building supergates and space ships seems to be an expensive and slow task, so waging two wars at the same time might be impossible.


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

[User]
[Star Trek] How does the holodeck create such a large simulation in such a small room?

At first I thought the ground might move on a principle similar to a treadmill therefore giving the illusion of more space but their are multiple instances of numerous people using the same simulation and they are clearly further away from each other than the room would allow so how exactly would it work?

[Assistant] Trick of light and separate moving tiles.  Away from each other the other person is hidden behind a holographic and sound distortion making them appear further away while still standing only a few feet away from you on a separate treadmill like plate from yourself.  Making it feel like you and them can move through a whole world despite staying in place.


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

[User] When Pluto was downgraded to a dwarf planet what was the cause of this? ie. more accurate observations? a recalculation of its size? A change in the definitions of planetary size?

[Assistant]
The cause of the "downgrade" was the discovery of multiple bodies that are now called "Trans-Neptunian Objects" (TNOs). These TNOs are of a size comparable to Pluto (but a bit smaller) and orbit the Sun in similar orbits.

Before these discoveries, it was assumed that Pluto was the only significant object in its orbital region, just like it is for the 8 planets. But the discovery of the TNOs showed that Pluto is different from the 8 planets in that it has a lot of compatriots in its orbital region.

This brought up the question of how many planets there are exactly. If Pluto is a planet, then one could say that several of the TNOs could be classified as a planet as well. So instead of facing the possibility of having to deal with a greatly increased number of things we call "planet", the decision was made to be more strict in calling something a planet.

In 2006, the International Astronomical Union came up with 3 requirements for something to be called a "planet" in our solar system:

- It's in orbit around the Sun.

- It's big enough to have reached hydrostatic equilibrium. In less fancy terms: It's (mostly) round.

- It's big enough to have cleared the neighborhood around its orbit.

That last requirement is the one that Pluto fails. It's not the only thing of importance in the area around its orbit. Along with the new definition of a planet, the definition of a "dwarf planet" was introduced, which is anything that meets the first two requirements, but not the third, and is not a satellite (moon).

This definition covers Pluto and several other TNOs.

So the short answer to your question is that the discovery of multiple objects that are comparable in size to Pluto led the IAU to redefine what it means to be a planet and this new definition dropped Pluto from the list of planets.


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

[User]
ELI5: Can countries do the opposite of a state seceding? For instance, could the US "kick out" one of its' states and force it to become its own country?

Couldn't find anything about this upon searching. Thanks in advance!

[Assistant]
Yes. In fact there have been nations that have been formed because they were kicked out. Singapore is an example - they got kicked out of Malaysia.

In the context of the US, there is no way in the US constitution for a state to be expelled from the union. Any attempt to do so would require an amendment of constitution. Actually, if the circumstances were ever such that a state needed to be kicked out for some hypothetical reason, it's likely that there would be a constitutional crisis.


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

[User]
[Batman] hello, 911 um there seems to be a break in (slight giggle) at my store on 11th and Broadway (light chuckle) can you send a squad car as soon as possible? (full blown outrageous laughter)

How screwed am I and would batman be able to cure me with anti joker toxin?

[Assistant] It's very likely you'll die, or at least have a major brain damage. However, there's some chance that you'll survive. In general, ever heard anyone important murdered in the last few months? You'll die. Ever heard of Baby Doll? You'll likely be saved in time, perhaps the gas isn't even lethal. Is Angel Rojas leading the GCPD? You'll probably fall into coma, but don't worry, Batman have the antidote. You're still screwed if your poisoned from liquid.


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

[User]
[TFS Dragonball Z Abridged][SPOILERS] When Goku and Gohan sneak back home after having fun with Broly, they are confronted by ChiChi....

Chi Chi says she wants a divorce. Now if she did get a divorce and also decided to try dating again which of the eligible bachelors would have the best chance and why? Also why would the rejected bachelors not get chosen? The bachelors that I know of are - Master Roshi, Yamcha, Piccolo, Napa, Pillaf, Shu, Mercenary Tao,Tien, Princess Trunks, Krillin, Mr Popo, and Mr Perfect Cell.

[Assistant]
Honestly can't see her going for any of them.

I could see Piccolo and ChiChi being a weird parental unit for Gohan, while Goku is either not bothered by this news *or* he becomes uncomfortably jealous.

Throughout the series (I believe it might have been in DBS?) ChiChi and Bulma joke about swapping husbands, so maybe if Bulma was pissed at Vegeta at the same time they might attempt to "husband swap" for a while (before obviously realising they prefer their old partner).

Anyone else would probably only be good for *trying* to make Goku jealous (and failing miserably, especially with Yamcha).


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

[User] ELI5: If people used to think the earth was flat, what did they think was on the bottom side?

[Assistant]
The "Flat Earth" thing is one of those insults that dumb people think makes them sound smart or science-y. Most scholars, and this goes back before Christ, knew that the Earth was round or at least spherical.

This Myth came out of the anti religous establishment back in the 1800's. Anti Christians have seized on it and use it as Strawman to attack people who don't support their own beliefs.

It would be very difficult to ascertain what ancient people thought was on the underside of the "flat earth" since most did not believe the earth was flat or did not even consider the shape of the earth anyway.


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

[User]
Academic workers strike part II: Would you still support the strike if it led to a substantial reduction in academic worker positions?

I saw on the previous post that there is overwhelming support for the strike. I am a supporter, but the one thing has given me pause is concerns from PIs that there would be layoffs and reductions in the number of personnel. This might ultimately be good for the field (to reduce the number of workers) but it certainly comes at a cost. So, follow-up hypothetical: **Would you still support the UC academic workers' demands if it led to high (say 25-50%) rates of layoffs for current graduate students, postdocs, and other academic workers, and commensurate reductions in the number of available academic worker positions going forward?**

[Assistant]
Yes absolutely. The solution to the low standard of living for PhD students and post docs has always been to hire fewer and pay more.

If you used to hire 8 PhD students at 30k each, hire 6 at 40k. If you used to hire 3 Postdoc at 60k each, hire 2 at 90k each. The fact is that universities view us as cheap labor, and so their incentive is always to have as many of us as possible given the available budget. We need organized labor, but we also need to be realistic. We can have a two birds one stone solution to low standard of living AND the over-saturation of the academic job market, but that will necessarily mean that these positions will be more competitive (which they should be).


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

[User]
CMV: Justice does not always mean equality

Let me preface this by saying that there is some justice that does mean equality. In this case Id be referring to race discrimination, and things that dont vitally make you different as a human being.

My point is, equality isnt always justice. For example, it would be equality to give men as long a maternity leave as women, but why do we not give men a long maternity leave?

Another example: equality would have everyone have the same opportunity for any job as others on the same level. Why do some jobs still attract more men than women while some jobs attract more women than men? Thats not equality!

The point here is, that equality is not the gold standard. For example, the sex divide. People of the two sexes are fundamentally different and as such need to be catered to according to their needs and not on the basis of equality.

I hope the idea is clear.

[Assistant]
>I hope the idea is clear.

The idea isn't really clear. You just asserted that justice does not always mean equality, but then gave a couple of examples where justice _does_ require equality. So your argument doesn't really make sense. Like, sure, equality is not _sufficient_ for justice, but it is a necessary component of justice.


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

[User]
How could smuggling gold into a country with a struggling currency negatively impact its economy?

I've just read an article which states that Sri Lanka is losing up to USD $30 million per month in foreign exchange, and cites gold smuggling as one cause of that. As a result of that, passengers are being forbidden from wearing 24k gold while traveling in or out of the country by plane.

I understand why smuggling gold OUT of the country could be harmful, but what economic harm could come from smuggling gold IN? Presumably people are smuggling gold so that they can sell it for fiat currency. I would think that exchanging their less valuable, inflated currency for a more tangible asset like gold, which holds its value and could be exchanged for more valuable foreign currency, would be an overall positive for their economy.

[Assistant]
Smuggled gold is income being generated that isn't being taxed, that is also in turn cutting into the profits of the legitimate gold trade for that country.

So the government is losing tax income and apparent GDP. This devalues the strength of the currency because the government that backs it is losing value via the aforementioned.


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

[User] Eli5: how does the finger clip with the laser at the doctors measure my oxygen level?

[Assistant] One  side of the clip has a light and the other has a sensor. When you clip it on your finger, it shines both red visible light and infrared light through you finger and it hits the detector on the other side after passing through your finger. Hemoglobin is the protein in red blood cells that carries oxygen. Saturated hemoglobin (full of oxygen) and unsaturated hemoglobin (not full of oxygen) absorb different amounts of infrared and visible light, so by comparing the ratio that the sensor detects to the ratio that was emitted, it can tell how much of the hemoglobin in your blood is saturated (carrying oxygen) and how much isn't.


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

[User]
[Zelda] Isn't Link destroying the economy of Clock Town (and also Termina) with his time-travel banking use? Or is Termina already suffering so intensely with inflation that it doesn't matter?

So Link signs up for a bank account on his first day in Termina, and gets a stamp on his hand that the banker updates *somehow* (AKA "special ink") every time Link makes a deposit or withdrawal. Link spends the next couple of days racking up tonnes of money from questing and looting, deposits it and gets his stamp updated to say he has 1000 Rupees in the bank. He returns to day 1 with the Song of Time, and so he *should* have nothing saved in his account right?

But because the stamp says he has 1k in his bank, the banker just accepts that this completely new-to-town-kid already has a grand in his yet-to-be-opened account purely on the notion that he *must* have deposited the money with the bank in order to have that ink stamp (and certainly not found another bank with the same system, forged it with magic or alchemical assistance, or perhaps created some kind of illusion to defraud the bank). As such, the banker happily forks over 1k no questions asked. Link uses the money to get better gear and equipment, does some questing, deposits more money and restarts the cycle.

Depending on how much Link deposits and then decides to withdraw *before he deposited it*, couldn't Link cause significant financial repercussions with his time-travel banking? I also considered that the economy has so much money in use that Link's paradoxical meddling is rather unimportant. After all, Rupees are found everywhere from unlocked chests to patches of grass. Shouldn't Termina be facing hyperinflation with so many enemies, plants and containers being loaded with cash *in addition* to what's being used in the economy already? Certainly can't help that Link routinely finds large value Rupees and adds them into the money supply on top of an already excessively cluttered currency system.

So how is Termina coping with the aftermath of Link's paradoxical banking adventure? Or is the economy already crippled long before Link arrives? Perhaps it's fine on both counts, but how would they achieve this?

[Assistant]
There are two mitigating factors here:

One, thanks to time travel, the most damage Link can do is to spend as much as he can in a single three-day cycle. Before the last cycle, he can do as much collective damage as he wants; the economy won't remember any of it. The biggest victim here is the banker, but...

Two, the banker never seems to run out of money, no matter how much Link demands. And as you say, he takes no issue with handing it all over without even trying to recognize Link's face. Dude's loaded, in contrast to his Hyrulean doppelganger; if Termina's economy breaks, this guy was getting it nice and brittle long before Link gets there.


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

[User] ELI5: when a balloon is popped, how is that pop sound produced?

[Assistant] sound is created through rapid vibrations in the air. when the balloon is popper, the elasticity of the balloon causes a huge amount of vibration in a short period of time. thus, a short and loud pop sound.


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

[User]
[DBZ] Why does Vegeta's tail not grow back after Yajirobe cuts it off?

Goku's tail used to grow back until it was magically removed. Also for that matter why did no Saiyan offspring after Gohan have a tail?

[Assistant]
>Why does Vegeta's tail not grow back after Yajirobe cuts it off?

Because he was an adult. They only grow back when cut off of children.

>Also for that matter why did no Saiyan offspring after Gohan have a tail?

It is not explicitly shown but it is likely that all first gen Saiyan/humans had tails removed at birth possibly with a more invasive and permanent form of removal.


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

[User] [Super Smash Bros.] How can non-Legendary Pokmon like Pikachu and Jigglypuff defeat Mewtwo?

[Assistant] I mean... Smash isn't accurate at all to scale for like any of the characters (a reminder that Kirby is only supposed to be like 8 inches tall) - because they're toys brought to life by imagination, not the actual beings the toys they're based on. So these fighters aren't using whatever stats that their counterparts actually have.


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

[User] ELI5: What is the difference between "software engineer" and "programmer"?

[Assistant]
You are getting answers in the theoretical realm.  In the practical realm it is a matter of semantics.  And it depends on the place you work on what you are called.

Someone called a programmer may actually be doing software engineer.  And some software engineers are programming.


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

[User] When I inhale a scent, do I also exhale that scent?

[Assistant] "Scents" are aromatic molecules that pass by your olfactory receptors, binding to them, and sending a chemical message to your brain. Not everything binds, however, and may pass into the alveoli of your lungs. Then, when you exhale, the molecules are expelled. So in a sense, you are exhaling the smell. More specifically, you are exhaling the aromatic molecules that bind to olfactory receptors, and they return to the external atmosphere.


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

[User]
How do barometers measure altitude accurately when air pressure is constantly changing?

Fitness watches or bike computers - probably some phones too - track altitude change via air pressure change, accurately enough down to the foot/metre.
How can they do this when the air pressure is always changing.
And how can they be accurate down to feet/ metres?

[Assistant]
If your question is how is this possible if there is a daily variation of the sea level pressure? Off from the 1013.25 average?

First, the pressure difference between different altitudes is (almost) absolute - so you can always easily measure the vertical speed. By tracking the difference you know by how many meters you moved up or down. The pressure at 0 altitude doesn't matter - only the difference does.

Those that give you an absolute height reading - it is always based off some estimate for the current ambient pressure. Those found in smartphones and GPS-enabled variometers use the GPS the get a rough altitude estimate. GPS has about 10m vertical precision. Then they use it to calibrate the barometric altimeter, which is much more precise. Some are better at doing this, others frequently give erroneous readings unless you manually calibrate them.


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

[User]
CMV: If men got pregnant and gender roles stayed the same, then abortion would probably be illegal and child birth probably mandated.

I've regularly seen a sentiment online like "If men got pregnant, and gender roles stayed the same, then abortion would be free and cheap for all" presumably because men have group power and group consciousness, and will exercise their group power to stop themselves from having unpleasant and painful obligations.

But I don't think this is true. Whenever in history there's been a political choice between men having autonomy and men being forced to sacrifice themselves for the state, men have been forced to sacrifice themselves.

Militias? Men were summoned. Wars? Men were conscripted. Taxes on being childless? Men. Work levies? Men. Obligation for Marital debt? Men. Even with childbirth, women tend to have financial abortion options with the chance to adopt the child at birth without parental consent, and men don't.

Whenever there's been an unpleasant public job to do, the state has been happy to sacrifice men, and men haven't freed themselves from it.

If a magical alien came and waved a wand on society and everything else stayed the same except men got pregnant, and so gender roles were the same and such, I would expect the opposite.

Pregnancy would be mandated for men, for the national good, with fines or imprisonment for men who refused, or in more liberal democracies simply strongly encouraged with fines and social pressure. That's what has happened in the past when men went against the public good to protect their bodies.

Opposition groups would likely be like anti war protestors. Mostly ignored so your side can wage righteous wars, except when it's politically expedient.

This is because people tend to care less about men, and want them to sacrifice themselves for the state more.

To change my view, show that society has on other matters let men go free when there was a choice between bodily autonomy and state benefits, or show that this is a bad comparison for some reason.

Edit. Since people have really pushed the boundaries of this hypothetical scenario, a clearer statement would be something like "In countries where there are strong anti abortion groups, if men got pregnant and gender roles stayed the same otherwise they would tend towards anti abortion laws, and when the state benefited from child birth, men would likely be forced to give birth, or strongly encouraged, as they are with military service."

[Assistant]
Historically speaking men have been the working class and women have been the caring class.

This why men have been sent to war (because losing men is not as important for population growth as losing women), done labor (because again women have tended to home and children) and all other things you said. This has been historical gender roles. This is also why men still earn more than women and why men are often considered breadwinners.

Breadwinners will choose to take career over family leave. If breadwinner gets pregnant that's almost one and half year minimum that you will not advance on your career or be able to feed your family. Breadwinner stays at work and wins that bread.

Now if this change comes overnight without anything else changing, already powerful career oriented men would stay career oriented. Therefore there is no room for unwanted pregnancy that would hinder that. There would be abortion kiosks on every street corner.


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

[User] [Phineas and Ferb] Why is the mayor's disgruntled brother allowed to run rampant through the city, running a company literally called 'evil'? Where are the cops?

[Assistant]
It's a free tri-state area. He can call his business whatever he likes.

Besides, what evidence do you have that the Mayor's weird, ugly brother is actually doing all of this stuff? Anytime something happens that an 'evil' company might do, another, less evil contraption and a platypus are in exactly the right place at the right time to make all the evidence disappear. We honestly just don't have anything on the guy.


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

[User]
Why are teeth individual and not one single piece of enamel?

It seems like it'd cut down on plaque related issues.

[Assistant]
If you were to damage your tooth to the point where it died and you only had one large tooth,  it would be very detrimental to your survival.  As it stand losing any single tooth is not a very large hindrance in terms of survival.

Having problems with plaque in between teeth is more of a modern occurrence.  Diets high in simple sugars along with a high rate of people getting braces leads to plaque problems.  If you were to eat a more traditional diet (think caveman) with larger gaps in between your teeth you would have very little problems with plaque to the point where brushing your teeth would be unnecessary.


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

[User] ELI5: How are casualties in battles/wars calculated?

[Assistant]
You know how many people you send in. And you know how many people come back.

As for the other side, an educated guess. And it helps that battles usually have a winner who have to deal with the dead left behind by the loser.

But yeah, there can be a lot of guesswork and estimation involved.


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

[User] Why do muscles shake when we tense them?

[Assistant]
Your muscles are innervated by motor neurons - nerve cells that signal to the muscle to contract. To activate a muscle, the central nervous system sends a signal via the motor neurons and the motor neurons "fire" on the muscle with pulses.

There are generally speaking three types of motor neurons which are classified according to how easily they fatigue. These are sometimes nicknamed as fast or slow twitch.

Now, even the fastest of these neurons only fire at around 60hz (60 "shots fired" per second), but the slower ones fire even slower, around 20hz per second.

The result of this is that muscle firing is that the movements (or in this case, flexing/tensing the muscles) is not a static thing but made up of fast "bursts" which cause this visible "shaking" to occur.

Now the more a person moves with the slower twitch fibers, the more obvious this shaking will be.

Does this answer your question?


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

[User] ELI5: Could living on/ mining the moon cause unintended consequences for Earth? e.g. changes in tide or anything else?

[Assistant]
Let's look at some numbers - the mass of the moon is ~7.348x10^19 metric tons.  It's composed of a number of different minerals, but assuming we need a change of at least 1% in the total mass, the only ones to really look at are aluminum and silicon.  On an annual basis, we're currently extracting and using 65M and 8.5M tons of aluminum and silicon respectively.  So, if we were to set up operations on the moon extracting 10 times that much every single year (so 650M tons of aluminum and 85M tons of silicon) how long would it take before we'd removed 1% of the moon's mass?

Just under a billion years.  The moon's *way* more massive than you might think.  We'll evolve into non-human creatures before we're able to affect the tides by mining the moon.


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

[User]
ELI5: Where do viruses go when they are quarantined, but not deleted?

How are they kept in the computer without further damaging the machine or running?

[Assistant]
Most anti-viruses do it very similarly. Here's what Symantec/Norton anti-virus does:

1. Load the malicious file into memory.
2. Encrypt it with a simple algorithm. (Something similar to subtracting 10 from every byte. So if the virus's code looked like KLM, the encrypted version would become ABC.)
3. Move the encrypted version to some folder like C:\Symantec\Quarantine.
4. Delete the original file.

The encrypted version is basically rendered inert; it's as if it's been deleted. The bytes in the file are completely different and cannot be run, opened, viewed, etc. If you open Symantec and view the quarantine folder, you can choose to restore it, which just means decrypting it and moving it back to its original location.

This is also why ransomware malware is effective. By encrypting every file on your computer and throwing away the key (retaining a copy for themselves, privately), they've effectively made everything inert, as if they deleted all your files. By paying money, they can send the key back to you.


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

[User]
ELI5: Why we tend to wake up right at the good part of a dream

I guess one of the best examples is right before any kind of sexual act is about to be performed (in said dream), but definitely applies to more than that.  Or the question could be geared to be "why does the best part of our dream occur right before we wake up?"

[Assistant]
I think it's because when you are woken up during a dream you are more likely to remember it. Dreams stay in your short term memory, but don't tend to write to your long term memory unless you actively wake up and try and recall the details.

So you may have had plenty of dreams that played out to 'the end', (whatever that is). But if you weren't woken up during them, it is far less likely that you recall them.


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

[User]
[X-Men] Where the hell is Jean Grey?

Sorry about my language in the title if it offends anyone. Is she alive? Dead? Stuck in a portion of the Phoenix Forces' consciousness?

[Assistant]
In the comics, she's currently alive and living on the Moon with her possibly-still-legal-husband Scott and her side piece Logan. Until recently she held a seat on the Quiet Council of Krakoa, but gave it up in order to join the Otherworld intervention force.

She and Scott are working to put together a new X-Men team, with the full roster to be announced at the upcoming Hellfire Gala.


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

[User]
What happens to a molecule which has an element which is part of its construction reach its half life?

For example, Carbon-14 has a half life of about 5730 years per Wikipedia, and since Carbon is a major building block of life C14 has found its way into all organic life on Earth in the same concentrations as we find in our atmosphere.  So what happens, for example, when one of these C14 elements reaches its half life in a molecule of an amino acid within our own DNA?

[Assistant]
What you'd expect, ultimately.

For starters, radioactive decay is more random than you're saying here. It's statistical. It's not that each Carbon-14 atom decays every 5730 years. It's that half the atoms in a clump of Carbon-14 decay every 5730 years. If you're watching one, it might decay in two weeks. It might be 20,000 years. No way to know.

Anyway, though, Carbon-14 decays into Nitrogen-14, with an electron and an antineutrino. CO2 is stable, now you've got NO2. It behaves like NO2 would anywhere else. More complex molecules may not be stable at all, and fall apart.

But lucky for you, you've got a LOT of carbon atoms in your body, and you don't live 5730 years. And the carbon in your body doesn't stick around your whole life. So you might lose a few amino acids to radioactive decay here and there, but it's not enough to hurt you.


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

[User]
[The Incredibles]Is Mr Incredible bullet proof?

Why Mr Incredible ever able to take bullets?

[Assistant]
You don't see him take bullets.... but he once accidentally used a butcher knife on his own hand, and it didn't cut the fingers. The knife got those almost-comical finger-dents in it.

I would think he could tank bullets.


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

[User]
ELI5: Why is it that were able to determine the origin of a sound in all directions despite only having two ears at left and right of our heads?

And similarly, do people with one damaged ear still differentiate between sounds coming from left/right, or is that ability lost?

[Assistant]
The fact that we have two ears gives us the ability to determine left and right, based on the time differences between when each ear receives the sound.

The fact that our ears are on the sides of our heads, *and* are shaped differently front versus rear, changes the "shape" of the sound wave our ears receive enough so that our brains can determine whether the source of the sound is in front of us or behind us.

Determining above and below works on the same principle as ahead and behind.


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

[User]
[Warhammer 40k] By the speed TAU is progressing will they be able to rival or even get more powerful than imperium?

They have shown to be remarkable fast progressor, i heard they were still discovering fire when impreuim was already established and they have already a space faring state, that's very impressive they progress faster than humans which would suggest that they will soon be able to outshine impreuim.

[Assistant]
Sure give them another ten or twenty thousand years of uninterrupted development and they may be as strong as DAoT humans were.

They won't be given that though as they are surrounded by enemies on all sides and currently their relative weakness is their best shield. When you are dealing with necrons, tyranids, chaos, and orks, the Tau rank pretty low on everyone's priority list. But it's unlikely they will be able to avoid destruction for long as they are in pretty much the worst place they could be bar the eye of terror.

Currently there are several tyranid hive fleets in their corner of the galaxy and while their ultimate goal is Terra, due to the astronomicon acting like a gigantic beacon to them, all it's takes is one fleet getting hungry and running through the Tau core worlds to utterly cripple them. Also they have an awakening necron dynasty next door, if they ever start expanding the Tau are screwed.


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

[User]
ELI5: Why does New York have three big international airports?

Wouldnt one be enough?

[Assistant]
Out of necessity. There are physical limitations on how many planes can land and take off in an hour on a strip. There are physical limitations on how many strips you can build on a dedicated space. There are minimum lengths to respect for a strip. This means that there is a limited number of flights to schedule on a specific airport. Also the airport has a limited number of people that can move around in it.

Given that, the other side is demand. NYC and its urban area has grown a lot these past 50 years. Also plane travel has increased exponentially.

Now the 2 have to meet. If the demand is too high for the supply of flights, you can act on the following parameters:

1 - Make planes land and take off closer to each other - Electronics help do that, but you will reach a physical limit. A plane creates turbulence and the one just behind can be subjected to too much stress (there was a plane crash 20 years ago over Jamaica, NY that showed this).

2 - Make bigger planes to transport more people - The 747 has gotten a bit bigger, and the ~~A480~~ A380 is humongous. But airport arrival areas are too small for the ~~A480~~ A380 and need sizable modifications. Now this increases capacity by 20 or 30% but not every airport or airline will buy a ~~A480~~ A380.

3 - Build another airport, in a different location. In NYC, this means 3 major airports.


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

[User]
[Star Trek] Do the Klingons continue to raid and conquer weak neutral planets throughout the TNG era?

In the original series, we see how the Klingons act during their cold war with the Federation. They have no Prime Directive, and it gets pretty brutal  at one point, they're threatening to execute 200 hostages every two hours until "Federation spies" are returned to them. They also have no problem interfering with a species' development by offering superior weapons to a puppet faction.

In Picard's era when the Klingons are Federation allies, are they continuing to expand their empire through violence and conquest? There are always new, young warriors who need to prove themselves in combat. And the galaxy is always a very dangerous place  skills must be kept sharp. A reputation must be maintained.

So all this time the Klingons are being our friends, are they also putting one-planet civilizations to the sword and carving a bloody path through the galaxy... just somewhere it's not bothering us?

[Assistant]
> In Picard's era when the Klingons are Federation allies, are they continuing to expand their empire through violence and conquest?

No. Griping about the Empire "losing its way" was common in both TNG and DS9.


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

[User]
What are Chomsky's main contributions, philosophically and otherwise, and how are they holding up with time?

Is it worth investing time into reading Chomsky? And if so, what are the highlights in his books and papers that are worth checking out?

I myself am studying cognitive psych and Chomsky was introduced as being the one that wrote the definitive critique of behaviourism and helped found the cognitive era, and I've seen a lot of his political commentary, but I'd like to know more about the bigger picture of his career and where he stands to contemporary studies in psych, linguistics, philosophy etc.

[Assistant] I can speak to some of the "otherwise." It gets overshadowed by his later work, but Chomsky's early work in computational linguistics is very important in computer science. Chomsky identified four classes of formal grammars and showed how each corresponded to a particular class of language and type of automaton (regular languages  finite state automata, context-free languages  pushdown automata, context-sensitive languages  linear-bounded automata, and recursively enumerable languages  Turing machines), and showed that these grammars formed a hierarchy of strictly increasing power.


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

[User] [Star Wars] Does the first order have planets? Are they in a full on war with the republic or are they more like a guerrilla terrorist organization?

[Assistant]
IIRC they were a military junta in the Unknown Regions. The Imperial Remnant still existed in the galaxy as did the New Republic, whilst the Resistance and First Order duked it out on the edges of civilization.

So yeah this trilogy was about a proxy war between two paramilitary groups. Riveting.


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

[User]
ELI5 why men are not allowed in playgrounds?

I went to use the bathroom and my dad waited outside. A group of moms was arguing with him and threatened to call the police. They pointed to a sign that said no adults without children are allowed. They backed off when I came out. I know it's weird my dad stays at home, but what's with the anger?

[Assistant]
Sexism.

One of the major sexist cultural towards men in the US is thinking that they're more likely to be pedophiles and that it's the only reason a man would be around a playground.

So the women were being sexist, and hassling an innocent man because of it.


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

[User] [SpongeBob Squarepants] What are Mermaid Man's and Barnacle Boy's powers?

[Assistant]
In the old days, Mermaid Man can control non-sapient creatures and can control the water around (Raging Whirlpool). Barnacle Boy can't control creatures, but he's more-or-less the same when it comes to his mentor's strength.

Obviously, they're both way past their prime nowaways.


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

[User] ELI5: Why can I search the whole internet in 0.58 sec but it takes over a minute to search a folder on my hard drive?

[Assistant]
Google doesn't search the whole internet for you when you enter a query. It searches a massive high-availability database stored on Google servers. The database is created by webcrawling, an automated process that goes out and *actually* searches the web, but takes a lot longer than a regular Google search.

On the other hand, when you search folders on your computer it usually has to *actually* search the files on your computer. The process can be sped up a bit if the files are cached, but it's still not the type of high-availability super database that Google uses.


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

[User] ELI5: Why do planes have different seatbelts to e.g. cars?

[Assistant] Aircraft seatbelts are designed to hold you down in the seat as turbulence is the biggest danger as the aircraft can drop suddenly. Car seatbelts are designed to hold you back into the seat with your upper body as the biggest danger is a frontal impact (to which a car is predominantly designed for, and which an aircraft isn't).


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

[User]
[My Hero Academia] How are quirks treated in the US?

It makes sense for quirks to be so heavily regulated in Japan due to Japan's anti-weapon laws. But what about the US? Since the US takes so much pride in the Second Amendment, are quirks protected under "the right to bear arms"? Does that mean that all citizens can use their quirks with no restrictions? Is that why All Might likes the country so much?

[Assistant] In a recent Vigilantes (a spin-off manga that is kinda good), Midnight mentions that quirks can be used for self-defense and others. The same manga also mentioned that the idea of licensed heroes was born in the US.


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[User] Eli5 Can someone explain about COBALT element and how harmful it is? I was reading about a COBALT bomb which some says is a myth but if it is true then it is way deadlier than H-Bomb.

[Assistant]
A traditional nuclear bomb, like the H Bomb, has a core of nuclear material that as it goes thru fusion or fission, it produces a large explosion.  The intent is to try to use up as much of that material as possible to produce the biggest explosion, but it doesn't work out that way.  As a result, not an of the nuclear material gets used up and is then scattered in the debris of the explosion.  This radioactive material becomes the nuclear fall out that becomes the next deadliest part of a nuclear weapon.  It's not intentional, basically a side effect of the design.

Cobalt bombs (not the tri-cobalt of science fiction) is designed to intentionally increase the amount of fallout by dispersing a radioactive form of cobalt over a much greater area.  Not only does it produce more radioactive fallout, but the cobalt isotope lasts much longer, not only affecting humans but making any crops unusable and poisoning livestock and wildlife with radiation.


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

[User] [Diablo] I just saved the world from three powerful demon lords. Then I woke up and everyone's acting like none of that happened, except all the monsters are much stronger than before. What the hell just happened?

[Assistant]
You're dead.

During your life you used, or kept company with those who used, dark magic or other unnatural abilities. You invoked artifacts of demonic origin. You desecrated holy sites.

Even if you started your journey for righteous reasons, you strayed from the path of light and spit in the face of the gods.

For that reason you have been assigned a sisyphean task, of endlessly repeating your past deeds. Perhaps one day your bloodlust and greed will be sated.


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

[User]
CMV: In Zombie fiction where everybody is 'already infected' or automatically zombifies when they die, bites from zombies shouldn't be a 100% guaranteed death sentence

This kind of a trivial topic compared to some of the other stuff posted in here, but this has kinda been bugging me. This mostly applies to The Walking Dead but could also work for other zombie series/media that doesn't have a virus or disease that can *only* be spread via bites or contact with infected bodily fluids.

But here it goes, if everyone is already infected with the zombie infection but only zombify upon death if their brains aren't destroyed, then a zombie bite couldn't be the sole cause of zombification, but rather sepsis/bacterial infection that leads to death and subsequent zombification (I don't know if that's the right terminology). So it could be inferred that if the bite victim was given antibiotics or antivirals then they could survive the bite and not die and zombify.

The zombie bite = guaranteed death trope has kinda been overdone and not really explored well outside of 'amputate bitten limb' which  doesn't make much sense because wouldn't the infection have already circulated through the body by the time amputation has performed, maybe someone with a medical background can clarify this?

Anyways I hope someone CMV on this topic.

[Assistant] The viral load means its airborne infection is low enough for your immune system to keep it at bay till death prevents it from doing its job and you turn, when you get bitten it pushes you over the threshold and your innate and adaptive immune responses are overwhelmed and you become a zombie. Makes sense to me! Lol.


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

[User] [Star Trek]Suppose a Starfleet ship (circa 2330s) is flying through space and they detect evidence of warp from a planet previously thought incapable of such. Does the ship make first contact right away, or contact starfleet to send in first contact specialists?

[Assistant]
The short answer is "yes."

By the 24th century, the Federation had a pretty good idea of what civilizations were on what planet in or near Federation space, and anthropological researchers would likely be stationed and be able to give the Federation a heads-up. If, for whatever reason, the traditional models utterly failed, the big question would be: why?

Let's take a hypothetical example: there's a civilization that has 19th-century level of technology. By all rights, they shouldn't reach anything remotely capable of warp for another 200 years. But, tomorrow, they launch a warp-capable ship. What the what now?

Uplifting a species is directly against the Federation charter (it falls under the Prime directive). Some other species are known to do this, whether for profit (Ferengi) or imperial expansion (Romulan, Klingon). Barring outside help, a sudden jump from steam to warp drive should be completely impossible.

So the starship in question would definitely want to stop by and see what could have caused such a precipitous event. The captain or other bridge officers would be trained well enough in first contact protocols to get things started while they wait for the real experts from Starfleet. In the meantime, they investigate as best they can the reason for the sudden technological advancement, which can be used to modify the models used to predict future additions to the galactic citizenry.


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

[User]
ELI5 - how symbolic languages as Japanese, for example, do to represent new things that never existed before? In latin languages we just use the letters and combine that to form a new word but what about symbolic languages?

I mean this: suppose a new product is launched in a west society and called "rumpa". Will japanese and other countries using symbolic languages like korean and chinese, use the word "rumpa" or create ideograms to say that? If they use the original spelling with our letters how native people that do not know our letters will say that word?

[Assistant] Chinese is the only major language (or, more accurately, group of languages) that's written purely logographically, i.e. with symbols representing entire words/particles/phrases. Usually they will combine other words to make a new one, such as *dinno* "computer" = "electric" + "brain". Korean is written completely phonetically, so there wouldn't be any issues there. Japanese has three writing systems, two phonetic and one logographic. One of the two phonetic systems, katakana, is used for loanwords for other languages, so that's what they would use.


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

[User]
[Thor 2: The Dark World]

The Dark Elves have been in a state of hibernation for thousands of years. How is it that there technology still matches, or even surpasses that of the Asgardians?

[Assistant] the asgardians have not improved their technology in thousands of years, not a single member of their group save odin and to a lesser extent loki even know how it works. Perhaps if they were not so throulary against cleverness and lateral thinking their society would not have stagnated quite as much, the fact that they are effectively immortal does not help with the stagnation problem.


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

[User]
[Warhammer 40k] Why was the Emperor such a terrible father?

The Emperor was supposed to be the most brilliant and powerful human to ever live. He single-handedly created the Imperium and one of the most powerful military forces in the galaxy. The guy was for intents and purposes omnipotent and he obviously must've also been intelligent and wise enough to be able to manipulate mankind from behind the scenes for thousands of years.

So that being said, why was he such a shitty father? The guy's not a moron, yet it's clear even to the dumbest of humans that a lot of the Primarchs had major issues. I mean, when one of your children is called *Angron* and forces all of his soldiers to implant machines into their brains that torture themselves for the rest of time, isn't that kind of a sign that he may have issues that need to be sorted out? The same thing goes for guys like Konrad Curze, I mean when your kid literally becomes Batman *but also slaughters people without a conscience* that should set off warning sirens, right?

His reaction to Lorgar in particular was a clear sign that he had no idea how to handle being a father. Here's a kid that loves his father so much he literally reveres him as a living god, and what does Big E do? He obliterates Lorgar's hometown and forces Lorgar to kneel in front of him and Guilliman. Did it not occur to him that this might cause a bit of resentment that might bit him in the ass further down the road? Why was he so oblivious to all of this?

[Assistant]
The Emperor was an excelent father. However, the Primarch's were never meant to be children. They were meant to be leaders of Mankind. Coddling them and doing everything for them kinda defeats the purpose...

As for their methods, he did object to some of them, Lorgar being the most glaring example. His approach was a bit heavy handed, but the Emperor had witnessed what Religion can cause, and really felt the need to try to nip that problem in the bud.

Part of the problem stems from the fact that the Imperium, even during the Great Crusade, was colossal. Not even the Emperor could manage everything, and he HAD to give increasing amounts of leeway to the Primarchs. The more independent authority they had, the more their individual problems became manifest.

Nikea was a perfect example of how the Emperor both understood what was happening within the Legions, and the root cause of it... It's also a prime example of the fact that he was quickly realising he had bit of more than he could chew, and that time was running out. His project became even more important, because he realised that micromanaging wasn't going to solve the problem, and he needed to cut the Legions off from their over-exposure to the warp.

If i were to put it in a parenting analogy... It's like discovering your child has cancer. It's inoperable, so you resort to Chemo while you try to develop something that will cure it. Then you discover the Chemo isn't working, and you've got 6 months to figure out a cure or its game over.

The Emperor realised that micromanaging wasn't viable, and needed another solution. He couldn't coddle them either, because it wouldn't solve the underlying problems.


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

[User]
Is tap water just as hydrating to the body as purified water?

Seems to be much controversy and not a straight answer via the interwebs.

[Assistant]
The straight answer is yes it is just as hydrating and it also has some sanitizing agents to ensure you aren't drinking any bacteria, as well as some other chemicals like fluoride to ensure your teeth stay healthy.

The only argument against tap water is if the levels of these, generally healthy and helpful, chemicals are too high which can make them toxic.  The government works on keeping them at safe levels though.  There may also be localized issues such as metal ion build up from old pipes.

edit:

This is assuming by tap water you mean from a municipal water supply in a developed area.  Well water has other, again individual, issues which you'll be responsible for checking.


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

[User]
Can you get sunburnt behind glass?

Now that i found the right subbreddit..

Hey Askscience :)

It's coming up on summer her in Australia and have always wanted to confirm the suggestion by a friend that you cannot get sunburnt behind glass, as properties of the wave are changed once they pass through the glass?

When i drive around in my car on a warm day with the windows up i can quite easily feel the heat on my skin, however does heat on the skin always equate to sunburn? Or is the fact i feel more heat behind glass to do with the change in the wave?

[Assistant]
From the Wiki

>Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths, whereas silica or quartz glass, depending on quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.[6][7][8]

UVA isn't as harmful but over extended time will give you a sunburn.  UVA is 400-315nm.

UVB is your main Sunburn exposure and where most people get into trouble with skin cancer, it is 315-280nm.  Glass blocks the smaller half of this very well, but leaves a sliver in the large end.

UVC is even higher energy, but the air itself starts to block most of this, it is a key component in the formation of the Ozone in the Ozone layer.

So yeah, you can get a sunburn from behind glass, but it will take a lot longer and it will be from larger wavelengths of UV compared to direct sunlight, so your cancer risk is lower (note: not gone).  Obviously treated or tinted glass can be made to block all the UV.


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

[User]
How come we can't dispose of waste in magma?

Due to the large amounts of landfill around the world, why can't humans dispose of waste in magma or volcanoes? I realize it would be very expensive to find places and transfer waste to these site, but wouldn't it be more helpful to the environment?

[Assistant] Burning waste without some kind of R.T.O. would be hugely detrimental to the environment. Remember that some of the waste would flash off before it hit the magma, and that the rest would burn on top. It would not be swept away and magically disappear.