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

[User]
How exactly does nothing (or almost nothing) react with glassware?

I've been watching CodysLab and HTME on YouTube and seeing them put all those incredible reactive and dangerous into glass started wondering why/how it works?  Are there other things that are as resistive to chemicals as glass is?

[Assistant]
It really depends on the chemical in question, but plastics can hold lots of things and even some things that glass cannot (think of how many household chemicals are sold in plastic containers).  Some metals are also great at holding things, especially various grades of stainless steel.

The main reason this works is that there are relatively few ways that glass can interact with chemicals inside.  The surface of glass is a bunch of Si-O bonds with usually H+ hanging onto the surface O, or some other positive ion like Na+.  For anything that isn't basic enough to pull that proton off the surface the glass will be fairly inert.  However, this means that glass is really bad at holding strong bases.  If you ever mix up a solution of NaOH you best store it in a plastic bottle.

Plastic is good in different ways.  Plastics are not usually susceptible to basic attack, and most are fine against acids as well.  However, some organic solvents can worm their way into the polymer chains and essentially melt the container or just leak through, and that isn't a problem organic solvents have with glass.


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

[User]
ELI5: What makes a film a "Film Noir"?

What are the "ingredients" please? Are there key themes? What are they?  Please ELI5 because I don't have the language to understand academics. Thank you!

[Assistant]
Film Noir is an artistic movement. It started in the 1940s when screenplays inspired by American crime fiction were brought to the screen, primarily by European directors.

The films share a certain storytelling: highly stylized, overtly theatrical, with imagery from an earlier era of German expressionism (a movement that started before WWI that rejected realism).

To this day the debate goes on as to whether noir is a film genre defined by its content, or a style of storytelling or identified by its visual attributes.


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

[User] [Star Wars] How does a Jedi go from 1 lightsaber to 2, or a double-sided saber? Do they get to choose?

[Assistant]
Depends entirely on the combat form they're using.

However most Jedi and Sith prefer the dueling/defensive styles, as a result not many use dual wields, or special variants.

Usually everyone starts with a single lightsaber though.


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

[User] ELI5: Screaming usually damages your voice and changes the quality of your speaking. How are horror movie actors able to get multiple consistant shots without their voices sounding scratchy or swollen in between scenes?

[Assistant] The final sound you hear in a movie, especially a scream, has very likely been enhanced or overdubbed in post production.  Thats also when they add the foley effects (sounds of walking, punching, etc).


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

[User] Are smell/taste memories as fallible as memories of feelings and events?

[Assistant]
I can't speak to the nature of sensory memories, but as someone who has studied cognitive  psychology quite a bit, the "weakness" of declarative memory that makes it vulnerable to manipulation is that it's tightly coupled with language. The memories themselves are stored symbolically, with words. Therefore, by accidentally accessing language that's not strictly tied to a real past event, you've now experienced a false memory.

In other words, when you access a declarative memory, it's not like you're accessing and replaying audiovisual security footage, but more like reading the notes of a stenographer. And it's easier than you might think to slip false facts into that stenographer's record.

It seems unlikely to me that this same phenomenon could occur with a sensory memory that isn't intrinsically linked to language in that same way. Other commenters have pointed out several plausible mechanisms for experiencing seemingly different sensations than you remembered from a prior experience.


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

[User] Is there any part in the body that cannot get cancer?

[Assistant]
Cancer is unchecked cell growth that interferes with healthy function by changing or blocking blood flow,  co-opting resources, and causing deterioration.

Both body parts and cancer cells that are alive need circulation. Ostensibly, "dead parts" like hair and nails can't get cancer because they are not growing. But they can be affected by cancer, certainly.


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

[User]
[Kill Bill] If Bill had confined himself to a wheelchair and didn't walk after the five point palm heart technique, would he have lived?

Let's say he had a wheelchair on hand. Would he had lived until he took those five steps?

[Assistant] As Bill proves, it is possible to survive for a while by not taking steps (he doesn't die until he stands up and walks away) but the strain of rolling a wheelchair under one's own power would probably serve the same result, so one would be forced to rely on others for any kind of movement.


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

[User] While the period of a pendulum is not affected by its mass, would it be affected by changes in the distribution of mass up and down the pendulum due to rotational inertia?

[Assistant] The period of a pendulum is affected by its length. Redistributing the mass at the end of the string changes this length. An intuitive example is sliding a weight up and down the string. The tension will act from the centre of mass of this object (the string below it will be slack) so as you re arrange the mass the effective length of the pendulum will change and hence its period will also.


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

[User]
If pi has an infinite number of digits, but it is non-repeating, then could you imagine any possible (finite) sequence of numbers and it is contained somewhere within the depths of pi?

We know that pi wont ever become a sequence of infinite 9s. However, does it contain a sequence of, lets say, 100 googolplex 9s in a row?

[Assistant] Nobody knows. There are plenty of non-repeating numbers that don't contain arbitrary strings of digits of your choice. For example, consider a number comprised only of 0s and 1s that follows no particular repeating pattern. The property of having all strings of digits in its decimal expansion is a consequence of another property called 'normality,' which is known to apply to most numbers, by some relatively advanced theoretical arguments, but we don't know very many specific numbers it applies to. It is most certainly not known for pi.


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

[User]
CMV: We need to allocate way more funds to just directly pay teachers more.

I believe that just across the board we need to raise the salary of teachers as a baseline. On top of that we urgently need more ways to compensate the extra effort that goes on outside of schooltime to be a good teacher.

My case is that:

A free market is good for the short term. However things such as education falls outside of its scope, because education very indirectly contributes to any single party's immediate success, yet it is arguably the greatest contributor to a society's success. In these situations, a government needs to step in and readjust the value of education so that it falls within the scope of a free market.

I believe that the recompense for an educational role is so far away from the value it brings to a society. The capability of being an excellent teacher is rare. It is also very valuable and transferable. And yet the reward for choosing an educational career pales so much in comparison to going into the industries.

I believe we should make it so that to a potential teacher, the choice of going into education or going into industry is tied or close to tied, with that particular person's passion being the tiebreaker.

[Assistant]
So are you saying that we need to re-allocate already existing funds to pay teachers? Or to just throw more money into the education fund?

The education budget has been increasing every year, but schools are choosing to spend the increases on things other than paying teachers.


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

[User]
[Marvel] So what's the deal with the multiverse now?

As far as I understand it, after Secret Wars, all the different realities got destroyed and then some of them got remade, but not all of them? So like 1610 is definitely gone, but is the main continuity still on 616 or is it something else now?

[Assistant]
Everything pre-SW was restored. We were led to believe 1610 was offed, but we've since seen it on (I believe) two different occasions (Spider-Men to name one).

Main continuity is still 616. The only real difference is that Miles and his close supporting cast now (as far as we can tell) exist within 616.


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

[User] ELI5: If hair and fingernails are made of the same thing, why don't your fingernails match your hair color?

[Assistant]
Even though both fingernails and hair is made of the same material hair also has something called Melanin in it that gives it color while fingernails do not.

Think of it as having made to chairs that re both made of wood, but one is painted the other is not. You would still say they were both made of the same material even though the painted chair also had paint mixed in with it's building material because the majority of the things (in this case wood) used to make the chairs was the same.

So yes they are more or less made of the same thing, just not 100% the same thing.


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

[User]
CMV: as real estate prices rise in major cities around the world, with a large variation in that price caused by foreign investment, the government should ban those who are not citizens (or have not been domiciled in the country for x amount of years) from purchasing residential property.

(There are obvious exceptions to this rule which you would expect to be combed out in the finer details. Inheriting property or those fleeing their own country for political reasons (see those from Hong Kong purchasing property in London now as a prime example.))

In many of the developed world's largest cities, real estate prices are rising at incredible rates. The average person entering the workforce now cannot reasonably expect to purchase a home for a very long time, compared to how generations above them did.

These housing crises are not being solved. Instead of affordable homes being built, private enterprise is building luxury homes for foreign nationals to invest in. These homes are being left unoccupied for long periods of time as they are owned by people with multiple homes and those living in other countries.

A further pumping of the price is caused by those investing in "buy-to-let" schemes in already existing homes, using renters to pay off their mortgage for them. This further bump in supply has exacerbated the price.

However, I am not arguing against the premise of buy-to-let. If buy-to-let schemes were only available to that country's citizens, house prices would decrease, and those investments could be made by those living there. By banning foreign nationals from purchasing residential property, housing can be made more affordable (fewer demand), while supply of affordable housing can also increase. The capital gains from buy-to-let schemes will remain in the country.

[Assistant]
Is the rise in real estate prices due to non-citizens buying homes? It sounds like the problems you've highlighted are using homes as investments, or buying homes for the purpose of renting. Neither of these depend on whether the person who's buying the house is a citizen or not.

Why is buy-to-let fine with citizens do it, but not fine when non-citizens do it?


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

[User]
[Marvel] What is the difference between magic and "energy"?

I read everywhere that Infinity Stones aren't magic, they include energies left from the universe's creation. Thus using them is not using magic but using the fundamental forces of the universe.

What I'm wondering is, what's the difference? Manipulating the primal energies of Reality to summon creatures sounds like magic to me.

So what's the difference between using the reality stone to summon creatures vs. using magic to summon creatures? What's the difference between using the power stone to send energy blasts vs. using a spell to send energy blasts? What is the difference between the energy within the stones and the energy magicians use?

[Assistant]
Comparing magic and energy is like comparing electro magnetism and gravity. Yes magnets draw two things together and so can gravity, but the mechanics behind them are very different.

> So what's the difference between using the reality stone to summon creatures vs. using magic to summon creatures?

We have no examples of this happening, so any explanation would just be speculation.

> What's the difference between using the power stone to send energy blasts vs. using a spell to send energy blasts?

Energy blasts from the power stone is the same energy used in forming the universe, energy blasts from magic is shaped mana from the caster.

> What is the difference between the energy within the stones and the energy magicians use?

Let's say we're playing World of Warcraft. A magician can cast a nice variety of spells there and a dedicated player can get pretty strong. Using the infinity gauntlet would be like a developer actually going into the program and coding out specific actions (though it's much more streamlined). Things that aren't possible with magic are possible with the infinity gauntlet because nothing is impossible for it.


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

[User]
[DC] How to resist psychic interrogations?

I'm a highly paid professional assassin and while I don't always hit my mark and my employers understand it's a bit much to hope for any hitman to take out Batman or Superman or whoever they're hanging around with lately it's still from time to time very important who hired me remain a secret in the event that I am apprehended and questioned on the matter. While it's easy to call Superman or even Batman's bluff when you realize they aren't actually willing to do anything permenant to you, it's quite another when they get someone like Martian Manhunter to do the weird glowy eye thing, so how can I resist that and keep my reputation as a discrete hitman secure?

[Assistant]
In one of the Children of the Corn films, a man is faced with trying to overcome the sinister psychic children named in the title. He discovers that by focusing on a phenomena or concept more powerful than even the supernatural Children, he could produce a resistance to their abilities.

He imagined the ocean. In all its majesty, it truly is a powerful and terrible force. Beautiful, yet deadly. Anyways, whenever they tried to probe or control him, he could resist by essentially just making his mind go turtle mode and not let them wheedle their way in.

With psychics, they often have to overcome your minds conscious thoughts to loot your subconscious. Once in, its a free for all. But if you can put up a stout enough defense consciously... you might be able to resist.


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

[User]
[Frozen] Can Elsa thaw natural ice?

When Elsa finally understands how love can overcome her fears, she manages to thaw the unnatural ice and snow that she accidentally created. But can she also thaw natural ice? For example, if she came across a lake that froze naturally during winter, could she unfreeze it? Perhaps more extreme, could she thaw a natural winter to create a magical summer?

Or is the "reverse ice magic" aspect of her powers exclusive to ice she herself created?

[Assistant]
There doesn't appear to be any difference between the ice she forms and normal ice, with two exceptions. The first exception is when she creates living things out of ice and snow - they can control themselves (and the big guy can even manipulate his body to produce more ice.) The second exception is when her magic interacts with someone - it appears to begin a process that slowly chills the person before transforming them into ice in a single move.

Beyond those exceptions, there is no indication that her powers wouldn't be able to affect normal ice, or that the ice she forms is in any way different from normal ice. I'd say yes.

On the thawing a natural winter to create a magical summer, though, thawing the ice doesn't necessarily make things *warm*. It's cold because the sun is hitting that part of the earth at more of an angle (instead of more straight on,)  reducing the heat that it receives. She might be able to thaw a winter, but the cold temperatures would remain.  Arendelle was in summer during the events mentioned, and so removing the magical clouds allowed the sun's light to warm the area.


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

[User]
ELI5: How capacitors work

I have a pretty good understanding of DC power, this just always confused me.

[Assistant] First you have to think about the fact that "current" basically means that negative charges are moving one way through a wire, and positive charges are moving the other way. A capacitor is basically two conducting plates with an "insulator" between them called a dielectric. The reason it is called a dielectric and not just a insulator is because it has special electromagnetic properties where it blocks the flow of current, but it allows an electrics field to pass through it. So what happens is, the dielectric material will block the charges from passing through it. This is sort of like a traffic jam, and negative charges will all start building up on one plate, and all the positive charges that are moving the other way will start building up on the other. There will be no current passing through the dielectric, but because there is a large difference in the charge of the plates (one is largely positive and the other is largely negative) there will be an electric field in the dielectric (which means there will be a voltage across it).


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

[User] ELI5 Why is everything in the universe spinning?

[Assistant] There is a wide spectrum of levels of rotational kinetic energy.  Zero is a very unusual value.  All non-zero values leave the object spinning.  So, spinning is the default state.  It's not at all like being in an atmosphere, where air resistance moves all things towards not spinning.  There is no resistance to rotation in space.


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

[User] TA in relationship with a student: must I tell anyone?

[Assistant] Involving yourself in someone else's stupidity never ends well.  Worst case scenario- they get in trouble, but nobody gets hurt, I'd say keep your head down.  If you want to help, the best thing you could do would be to let them know they're not as discrete as they think.


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

[User] ELI5: how do gnats just "appear" in my house overnight?

[Assistant] Could be fruit flies. They lay their eggs on soft spots on fruit, which you may then take into your home, where they hatch. If you have a lot of fruit about, they may then subsequently lay more eggs on more of your fruit, and you wind up with a pest.


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

[User]
Does the moon get earthlight, like we get moonlight?

While the moon is on the sun side of earth, does the dark side of the moon get reflected light from earth. Would the earth have "phases" like the moon or is the moon not large enough to do that?

[Assistant]
Certainly.  The dark part of the Moon is faintly visible because of this.

The phases depend only on the angles of the Sun-Moon-Earth triangle, not on the sizes of the Earth or Moon.  If you swap the positions of the Earth and Moon, someone on the Moon would see the same Earth phase that an Earthling would have seen before the swap.


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

[User]
ELI5: What would happen to airplanes during a massive power outage?

Assuming all the planes themselves didn't lose power, just a massive power outage on the ground. Could most planes safely land?

[Assistant]
Major airports have backup generators that would power them long enough for the planes to land.

Failing that, planes can always talk to each other, and negotiate who is landing where.  In fact, this is how it's done at small airports that don't have dedicated air traffic controllers.  If there weren't any more planes going out (due to the power outage), it would significantly cut down on the amount of runway and air traffic, too.


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

[User] ELI5: Why is the triangle the 'strongest shape'?

[Assistant]
Because you can't change the angles without change the lengths of the sides.

With a square, it can deform into a rhombus without bending or otherwise changing the lengths of the sides.  With an equilateral triangle, you have to do both.


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

[User]
[Matilda] What would've happened if Bruce Bogtrotter was seriously injured when Miss Trunchbull smashed that plate on his head?

It's used as a quick gag to end the triumphant scene of an obese child being force-fed an entire large cake by a 'roid head... Okay, it was indeed pretty awesome and watching The Trunch's breakdown was glorious... but glass most-definitely *isn't* fragile like it is shown in film.

At the very least, Bruce is going to get his head cut to pieces by glass debris; at most, Miss Trunchbull cracked his skull or gave him a lethal concussion.

So did Miss Trunchbull ever consider what would happen if she... I don't know... killed a student in front of a hundred witnesses?

[Assistant] They're elementary school students, nobody is going to believe them when they say Trunchbull murdered a student.  The police are going to assume it was an accident, and the children are blaming the authority figure because she's unpopular for enforcing discipline in the school.


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

[User]
[Star Wars] How many Jedi/force users survived Order 66, and how many were alive/are currently alive in the Star Wars canon?

By "now", I'm talking about after the events of Episode 7.

As we've seen in Rouge One, we'll be getting a blind force user who will accompany the rebels on their mission to steal the Death Star plans. My question is, how many force users or Jedi were not executed during the Jedi purge, and of those, how many (if any) survived through the original trilogy (4,5 and 6)?

[Assistant]
You'll never have a complete accurate list of all Order 66 survivors, at most we have a list of individuals that we know survived.

Also, Order 66 specifically targeted the Jedi, no other Force users. We are currently unaware of whether or not any other Force traditions got destroyed under Imperial reign.

One more thing, the character from Rogue One you mentioned isn't a Force user - just one that practices a religion based around the Force.


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

[User]
ELI5: On staplers, whats up with the other side of the plate? When would I need to reverse-staple something?

Neat, so it's called pinning. Good information to know. But no one has answered the second question, when would I use it? Would this be common knowledge if I was a paralegal or CPA or some other career that deals with collating papers?

[Assistant] Pinning is midway between a staple and a paperclip.  It's more secure than a paperclip, but more removable than a staple.  You use it to temporarily bind two things together, knowing you want to separate them later.  This can be used when you want to attach to pieces of cloth together for sewing, but don't want to use straight pins or safety pins or two pages when you only need them attached temporarily.


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

[User]
Why do elements need 2 or 8 electrons in their outer shell for it to be full? What makes these numbers so special?

Does the fact that they are both powers of two affect this phenomenon in any way?

[Assistant]
This has everything to do with quantum numbers. In general the shrodinger wave equation describes all the ways electrons can interact with an atom. Each of these different ways is associated with a different set of quantum numbers. If you're asking what is stable you're simply adding electrons to an atom in order of lowest energy and keeping track of how adding each additional electron affects the overall energy of the atom.

The way this works out is for non transition metals you have two orbitals S (sphere like) and p (dumbbell like) . The p orbital has 3 orientation that solve Schrodinger's equation (x y z). The final piece of the puzzle is that each one of these four orbitals can hold two electrons (spin up and spin down). It turns out that when you have both spin up and spin down electrons an orbital becomes much more stable. Therefor you either have two electrons and a full S orbital which is stable. Or you need 6 more for 8 to get a full P orbital.

Of course this is a general rule and for many elements the stability might be different. ( The transition metals for example are very ruled by the D orbitals and can shuttle electrons from S orbitals to fill D).


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

[User] What shape is the universe? Also what's outside of the universe?

[Assistant]
Measurements indicate that the Universe has overall flat curvature.  Why this should be the case is contested, but that's what the data suggests.  This also means the Universe is probably infinite in all directions, though not the *Observable* Universe.  It's hard to grasp what curvature means in a 3D space but it's mathematically well-defined and has to do with whether or not parallel paths remain parallel - in curved spaces, they will not, either converging or diverging.

Outside the Universe is a question which we cannot currently answer, and may possibly not be able to answer, since we are limited in our scope of what we can observe.  In fact, the question may not even make sense, philosophically-speaking, since outside implies space and space is a property of the Universe.


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

[User]
[Star Wars] Why is Darth Vader able to block blaster bolts in ESB, but we never see such an ability used ever again?

First what allows him to do this, the force? Second why don't we see this used more often as a tactic to avoid death?

[Assistant] In the EU, this is chalked up to a particular aspect of Vader's suit - that is, the gloves were a variant of Mandalorian Crushgaunts, incredibly rare and expensive armor pieces. Although resistant (not indestructible!) to blaster fire, actually 'catching' blaster fire was something that would require force sensitivity to predict the bolt's path as well - and this doubly-rare combination combination of gear and skill was rarely seen together; Vader is the only known Force-sensitive to use a pair.


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

[User] [Matrix] What happens if the One dies prematurely? A sentinel gets a lucky laser round at the end of the movie while Neo is hooked up. Do the robots have a contingency?

[Assistant]
The One is an emergent property of the system, and aren't actually the sort of official "One" until they actually return to the source.  If Neo gets aced, he just dies, and a new prospective One emerges.

This could be problematic for the machines, but we do know there is at least some wiggle room, as the Matrix didn't immediately implode when Neo refused to return to the Source.

Then, worst case scenario, as mentioned by the Architect, is that the Machines just let the Matrix crash, lose that crop of humans, and start over from scratch.  It's not their preferred solution, but they would survive it.


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

[User]
Can you build a program in C++ to compile any language?

I was reading up on how Node.js came about, which lead me to Google V8 and what it was. I know some Java, and not C++, and the "compiling Javascript to Native Machine Code" description, finally made me interested in the JVM, and made me look up some of the differences between Java and C++.

So, is there something special about JavaScript that lets C++ make a program to compile it, or can it do with any language?

And when you do something like that, how complicated of a task is it? It seems pretty complicated to build a program from another language, whose purpose is to understand another language and then compile that.

[Assistant]
Yes, you can write a compiler for any language in C++. In fact, you can write a compiler for any language in any language, because all a compiler does is read your source code file and write another file that your operating system and CPU are able to interpret; that obviously requires knowledge of the OS and CPU your compiler targets. A program that has input and output is by definition "a program".

Writing a fast virtual machine (like the JVM, or even VirtualBox/VMware/dotNet) however, does require a programming language that can direct the CPU to execute any code it wants directly. That's something that C++ and C can do, but there's no implementation of JavaScript or Java that can do that directly. (Oversimplification alert: you can write a very small unit of code that your Java VM will load via JNI that could do that... but that's not Java anymore).


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

[User]
META: I'm concerned that this place is getting trolled like Yahoo Answers.

Looking at some of the questions, it seems to me that an awful lot of people are just in it for the lulz, finding the most abstruse possible questions to ELT5.

Yeah, funny the first dozen times.

Can we move on, though? This place has a whole lot of potential, but if it just fills up with endless iteration of the same joke, only the trolls will remain.

Could we consider making a point of downvoting the obvious hyucks?

[Assistant] Most of the trolly questions get answered adequately.  The problem isn't trolling, but that the same troll questions get asked over and over.  Rather than using the sidebar for the announcement, it might be more useful to use the sidebar for the top twenty re-asked and already-answered questions.


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

[User]
[The Batman/DC] Is the Riddler smarter than Batman? SPOILERS for The Batman

So after watching The Batman this weekend, it kind of surprised me that Batman essentially lost. The Riddler accomplished almost all of his goals. Everyone is talking about this movie showing how good of a detective Batman is, but in the movie the Riddler is really just pulling his stings the whole time, and Batman just plays along by solving his riddles. He doesn't ever outsmart the Riddler.

Does anyone else have this interpretation of The Batman? In other Batman stories, is the Riddler shown to be smarter than Batman usually?

[Assistant]
Think of it this way, the Riddler had over a year to set up his plans and Batman had a few days to solve it. Twice he missed a clue, one of which was so open that it could've referred to any number of things and the second time was a relatively short time after his father figure almost died and relied on a very specific tool that only one guy knew about because his father happened to have a niche job.

As for how clever the Riddler is compared to Batman, he's generally supposed to be a much better cryptographer and detective. Batman has admitted that the only reason he can solve Riddler's crimes is because he compulsively leaves clues about the next crime.


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

[User] Is boiling hot water more effective at killing bacteria than a dish soap?

[Assistant]
There are a lot of factors that go into this and it's impossible to answer the question without defining things more strictly.

Dish soap will absolutely disrupt cell membranes for bacteria, but its effectiveness will vary depending on the soap's concentration. Boiling water is a very effective disinfectant, but the time that water boils is an important consideration. Briefly dipping an object in boiling water won't completely sterilize it, while boiling for an extended period will. It's also going to vary depending on the bacteria. Some will be more or less vulnerable to soap, while others will be more or less resistant to heat.


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

[User]
[MCU] Why does Heimdall send Hulk/Bruce Banner directly to Dr Strange?

I know Heimdall sees all, and possibly knows Thors connection to him, but considering they both go straight to Tony Stark right after, why not just send him straight to Tony, or better yet, send him to Captain Marvel!?

[Assistant]
Heimdall sees all in the nine realms, which are nine cosmically linked regions of space. Captain Marvel is out in space who knows where, almost certainly beyond his vision.
As to tony vs Strange, Heimdall is a member of a society that has completely leaned into the 'sufficiently advanced technology is indistinguishable from magic' vibe, and has a bit of a condescending attitude towards technology that still looks like technology. In a pinch, he's always going to go for the magic user.


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

[User]
[Batman] On that fateful night, the Waynes ultimately decide to stay home. No tragedy occurs, they live a normal life. What does Gotham look like today?

Does a Batman arise? Does some other hero patrol Gotham's streets? Do supervillains even come to the city without a superhero to clash with?

[Assistant]
Gotham is almost certainly better off. Thomas and Martha spend the rest of their lives pouring their wealth into helping the afflicted and the poor, instead of their deranged son donning body armor and attempting to do the same with his fists.

Edit: Gotham is good until Darkseid shows up. Then humanity dies. Earth needs Batman.


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

[User]
[The Martian] What did NASA change in later Aeres missions after the Aeres III incident?

I'm sure their after-accident report has plenty of suggestions to avoid similar incidents in the future, and improve survivability in similar situations.

[Assistant] Redundant comms systems at landing sites. The MAV has three comms systems but it isn't automatically good to go when you get there. The Hab only has one long range radio and its apparently pretty dinky.


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

[User]
[The Stand] Why didn't Randall Flagg allow vices in Las Vegas?

In a scene in the mini series, a couple of guys sitting around a campfire mention that Flagg didn't allow hookers, dope or drinking in Vegas. Why was this?

You'd think the "evil" city would allow people to partake of their vices. Obviously those in Flagg's inner circle (like Lloyd) were allowed these things.

And since I'm sure Mother Abigail's community wouldn't allow those things either, (except drinking apparently) where's a dude gotta go in post-SuperFlu America to have a good time?

[Assistant]
Think of it like this: He's not trying to build the Weimar Republic. More like the Third Reich.

You want productive, obedient workers, not ones that are freebasing junkies.

It's a world full of pharmacies just ripe for the looting, full of oxycodone and amphetamines. All it takes is one guy to come up from Cartel territory in Mexico with a truck full of coke and heroin, and the city could become a junkie-infested, unproductive town. It's not like there's a whole hell of a lot of people left, and a few kilos of heroin is a lot of doses, let alone when someone brings in a ton of the stuff in a cargo-truck.

He wants an army of soldiers, not junkies. Now, if it came down to the actual war between Boulder and Vegas, for the big push, he might have his pilots pop go-pills, his tank drivers loaded up on amphetamines, ala the Blitzkrieg, but for a productive society on a day to day basis, you can't have everyone high out of their minds.

I think Mother Abigail's community had a pretty permissive drug policy to be honest.


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

[User] ELI5: How do the carcasses of marine animals, particularly large ones like whales, not spread diseases throughout the ocean?

[Assistant]
The same reason the carcasses of land animals don't spread diseases: it's difficult to spread diseases when you don't move around, and they're eaten before they have a chance to do much moving around.

Apart from this, diseases that thrive in warmblooded air breathers rarely do particularly well in cold blooded water breathers. The environments are simply too different.


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

[User]
ELI5: How do lungs clean themselves out?

Besides coughing and sneezing, which I understand *outside* of the lugs. So like, what exactly is happening when a smoker quits smoking and lungs get to work expelling gunk?

[Assistant] Your lungs are always "expelling gunk" by using a massive network of what look like little tiny hairs capable  of movement. These hair like cells are called cilia and they slowly move anything that shouldn't be In the lungs out.  Most of what's moved out ends up going down into your stomach  as you swallow. But some get coughed up.


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

[User] [O Brother, Where Art Thou?] The KKK was a political force to be reckoned with in the 1930s, so how did Pappy O'Daniels create and maintain a political powerhouse without their support? Conversely, why did Homer Stokes lose his bid for governor despite having the support of the 'silent majority?'

[Assistant]
Money changed hands, extensively.

As for the 1937 gubernatorial election... you're not taking into account the sheer star power of the Soggy Bottom Boys. Their cover of "Man of Constant Sorrow" took the south by storm, coming as it did in the midst of a major fad for old-timey singers. Stokes made an enemy of what was, briefly, the biggest act in the entire state, who threw their endorsement behind O'Daniels. That was enough to tip the scales.


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

[User]
What will happen to a piece of wood, placed in a "pot"with no oxygen and then placed over a fire?

also the same question but what if the "pot" was pressurised?

[Assistant] That's basically a way to make charcoal. By starving the wood of oxygen you allow the moisture and volatile compounds to be burned off leaving you with  a mostly pure carbon. It's important that it has some kind of vent though because the steam and volatile compounds will pressurize the container.


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

[User]
Is there any way to utilize "undefined behavior" in C/C++?

In class, I have learned to avoid things that might lead to undefined behavior (like division by 0). But I was thinking that if you needed something unpredictable or random, could there be a case where you would intentionally do this?

[Assistant]
Undefined behaviour means the standard doesn't say what to do in that case, and each implementation is free to do as it wants. Crashing being a valid option.

And division by 0 is very well defined for floats ( IEEE 754)


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

[User]
ELI5: How does oily skin cause acne on face?

Can someone please explain the process of pimples forming that is caused by oil to me?

[Assistant] The oils block up your pores in the skin.  They build up more secretions behind it, including bacteria and various other lipids and fluids.  The raised tension behind the buildup causes the visible red bump of the pimple.


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

[User] Why do we teach braille to blind people instead of stamped normal letters?

[Assistant] Stamped (raised) "normal" letters would need to be considerably larger than braille characters in order to be distinguished from one another through tactile sensation. Large enough that the finger tip would need to move, or trace, the letter.  If you were to make the letters smaller, several letters would be too difficult to distinguish.  With Braille, the finger doesn't need to move for one single character.  And the dots are simply easier to feel.


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

[User]
[MCU] Would learning about Thanos and the infinity stones have changed the events of 'Civil War'?

The whole conflict of CW seems so insignificant in comparison to the possible destruction of half of the Universe (if they follow the comic book route). At the very least, the threat level is cosmic tier.

[Assistant]
In a way, Tony had already been worrying about Thanos, he just doesnt have a name for the impending threat. His all-consuming worry was manifested in the work he does in IM3  An army of clumsy semi-autonomous suits of armor + a subtly introduced ability to personally control a suit remotely (Tony was becoming afraid to be on the front lines due to his PTSD so he creates what is essentially drone armor.

By the time of AoU he refines the concept with the creation of the more elegantly designed Iron Legion but at this point he had hit a technological wall Jarvis is merely a faade of artificial intelligence.  The Wanda induced vision drives Tony to pursue the Ultron initiative. But once again, our modern day Icarus flies too close to the sun and Sokovia paid for it.

So as we head into CW  Tony still has this impending threat on his mind only now its been driven home that he cant science his way into a solution. He has never been so humble as we see him in CW. The only thing he can do is keep this group of powerful friends together so they can be ready for the next invasion.

Like Tony, Thor is aware of the danger, he simply lacks a name for it. Yet.

Cap pretty much proved why future proofing against an invasion is a fruitless endeavor in both CA:WS and AoU It never works out. That kind of power ends up corrupting the original good intentions.  He knows it could happen again but he isnt willing to betray his principles to counter it.


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

[User] [Infinity War] When Strange is looking at the 14,000,605 possible outcomes, how does he perceive them? Does he see them one at a time, perhaps sped up? Does he see them all at once?

[Assistant]
One fan theory described it as watching 14 million lights, then watching them blink out one by one. Then he fast-forwarded to see if any came back on, even for a brief moment and then examined them closer to find a pattern of events.

As he had already spent a long time being repeatedly killed by Doramammu we can assume he has *some* kind of magical protection against the insanity surely caused by experiencing such loops.


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

[User]
Dumb Question: Why can't airplanes be fitted to huge (~ mile wide) parachutes to slowly come down to the ground in case of an emergency?

From a physics standpoint, a large enough parachute to withstand the weight can probably be made.  Even if it slows the plane down just a bit, it could save lives. I'm sure there is a reason this hasn't been done, but I'm just not aware of any.

[Assistant]
Because for most all airplane crashes, it wouldn't help. Very rarely is a plane somewhere out over the desert when suddenly "boom!" all power is lost and it starts plummeting towards the ground, everything else in tact.

Airplanes normally crash during takeoff, landing or due to catastrophic failure. During takeoff and landing, the plane is too close to the ground for a parachute to work. During catastrophic failure, who is to say that the parachute would still work? Also, you can't just deploy a huge parachute, it would have to be a complicated system of drag chutes to slowly slow the airplane down. If the plane is spinning, well good luck.

Ejection systems from fast moving objects are a topic of research. But the fact is, when you are moving that fast, it is hard to get down safely. Fighter pilots have to train for it, astronauts have a very elaborate evacuation procedure, but it only works for the smallest of time windows. If it were as simple as a parachute, it would probably be installed.


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

[User]
How Does Auto-Shut Off Engine Design Not Destroy Engines?

I rent cars quite a bit for work and over the last six months I have gotten a handful that have a feature where they basically shut off when the car stops and then start back up when the car tries to move.

I've been told starting up the engine is one of the harshest things an engine goes through, yet this approach to design seems to unnecessarily add a ton of off/on cycles to a drive.

Is the notion / assumption that start up is the harshest out of date or are special precautions taken to mitigate the damage of this particular feature?

[Assistant]
Starting an engine is only harsh when all of the lubricants have trickled away from the bearing surfaces.

Worst when the engine is cold because that is when lubricant is most viscous and slow to circulate. Exacerbated by richer mixture (in a petrol engine) needed for cold start that washes some oil from the bores.

None of these are of consequence when the engine is warm and only been off for a minute or so. Auto start systems will even restart the engine occasionally if you are stopped for a long time, say in a traffic jam.

Wear an tear on the starter is minimal. A good modern warm engine will fire on the first compression stroke. Starter has to only compress one cylinder stroke. Nothing like cold start cranking.


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

[User]
How does a fan cool down a room?

like i understand how a ceiling fan can push hot air where you want i (heat rises etc.) but how does a desk fan which simply circulates air make a room feel colder? does it? is this just an illusion?

[Assistant]
A fan doesn't cool the room (unless it's colder outside, there's an open window or door and the fan helps the airflow through it).

However, we experience heat not necessarily by the absolute temperature of the air around us, but rather by the rate at which heat is exchanged between the air and our skin.

When there's air flow around us, our bodies can get rid of heat more easily, which causes the sensation of cooling.


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

[User]
ELI5: why is gold so valuable ?

But really, why does gold have so much value? Why not copper or silver?

[Assistant] Because it's rare, it's portable, it's easily identifiable, and rich people like to dangle it from their bodies and fashion their belongings out of it, all of which makes it a perfect candidate for a kind of unbacked universal currency.


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

[User]
When patients get blood transfusions, does the blood need to be warmed up to body temperature or can it just go in cold?

I've seen on a lot of medical dramas (I know that they're not always accurate though) that blood bags are kept in coolers. But when the doctors put the blood into a patient, is it warmed up? If so, is there a specific tempature it needs to be at?

[Assistant] Warmed.  Even in an emergency, blood can go through a rapid-infuser which also warms the blood.  Some blood products (like plasma or cryoprecipitate) are frozen and need to be thawed before the blood bank issues it.   - signed your friendly neighbourhood laboratory professional :)


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

[User]
What is the 4D equivalent of 3D volume?

Is there a different/special term for the space a 4D object occupies in 4D space?

Thanks in advance.

[Assistant]
Some suggestions:

* Hypervolume works in the same vein as hyperplane etc. A lot of syllables though.
* Measure is the general term for what you are talking about, but it's very general so make sure it's clear from context which measure you mean. This is usually not a problem.
* Content is one of those great flexible middle-ground words that you can define on a paper-by-paper basis.
* Prefix by dimension, e.g. 4-volume, 4-measure, 4-content. Useful if you have to deal with many different dimensions.


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

[User] ELI5: What does a pilot see when they say turbulence is to be expected for the next X duration of the flight? How do they know how rough it is going to be? Why can't they just go higher or lower than whatever the weather is?

[Assistant]
It depends where it is.

Sometimes it's possible to see bad weather visually - large cumulus clouds are nearly always turbulent. Other times it shows up on the weather radar - a device which sends out a radar signal that bounces off of water droplets and shows how big the droplets are.

Clear Air Turbulence is the one that's most hard to spot. Mostly, pilots rely on reports from other pilots ahead of them on the same route. This is especially true on routes like the North Atlantic, where communication with Air Traffic Control is difficult. In other, more populated areas, Air Traffic Control might collate information from pilots.

And finally, there is often turbulence near the ground, either due to the wind being mixed up as it blows across trees, buildings or mountains, or due to the thermal effect of the sun heating the ground, and the ground heating the lowest layer of air, which then starts to rise. But usually you'd have your seatbelts on for take-off or landing anyway, so no special action is required to warn you of that.


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

[User]
ELI5: How come my twins have blue eyes when both my husband and I have brown eyes.

We have 3 year old twins (non identical) who both have the exact same shade of blue eyes. I have brown eyes and my husband has hazel. Their paternal grandfather has blue eyes, their maternal grandparents have brown eyes. Both my grandmothers had blue eyes.
I know that the gene for blue eyes is recessive, so I'm curious how they both by-passed all the brown eye dominant genes!
Thanks!

[Assistant]
Genes work like this: we have two sets of genes for everything (only exception is the gender-specific ones), one passed on from the father, one passed on from the mother. Which of the two sets of your parents you inherit is entirely random.

This simply means that both you and your husband inherited one set of brown-eye-genes and one set of blue-eye-genes from your respective parents and you both passed on the blue-eye-genes to each of your twins. Unlikely, but entirely normal.


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

[User]
[Star Trek] Why doesn't anybody seem to care about the temporal prime directive?

While the "normal" prime directive is a enforced strictly (with some exceptions), Starfleet is pretty loosey goosey when it comes to interfering in past events. I can count numerous times when the Enterprise-D alone has meddled in history, not always in a way that was inevitable or necessary for survival or to complete the mission at hand (taking freakin' Mark Twain for a tour on the ship in Time's Arrow, for example). Doesn't anyone seem to mind it? Due to the complexity temporal physics, it can be argued that this type of meddling could be quite dangerous, even more so than violating the "normal" PD.

[Assistant]
One of the problems is that Star Trek never really defined how time travel works. Do you need to worry about killing Hitler, or will *something* always prevent it from happening before his recorded death, either via your efforts or that of the time cops from the Future Federation?

Just claiming that traveling back in time can't affect the future is paradoxical if one assumes that there is only one timeline. Either you *always* went back and meddled or you *never* did. Further, with this model, you *can't* change anything that you'd notice, because you are a product of history. If you remember Hitler being killed in 1939, then you'll never travel back in time to alter that fact.

The closest this came to happening was the episode "Yesterday's Enterprise." Only a higher-dimensional being, Guinan, could even suspect something had altered time, and in the end, she was the only one who knew anything happened (until Denise Crosby showed up again).

In order for you to remember why you traveled into the past to change something, you'd have to forge a new timeline when you arrived. You could alter whatever you wanted willy-nilly, since you've basically entered a new universe that branched off from your home universe the second you showed up.

Now, what I'd assume the Future Federation would have to be is some group that exists outside of spacetime. In essence, they'd have to observe from another universe somehow, so that they aren't subject to the causality changes. There's a series of Asimov short stories about that, where a group of volunteers (since you're basically signing on to *technically* not exist due to alterations in history) will study the timeline and decide what events, starting with the founding of their organization, results in the best possible outcome. Then, they work to steer history towards said outcome, able to watch and remember changes due to being outside of the universe where they take place.


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

[User] If pi is irrational, and therefore it is impossible for it to be expressed as a relationship between two (real) numbers, then how can it be the relationship between a circumference and a diameter?

[Assistant] Not two real numbers. Two integers. If the diameter of a circle is an integer, the circumference will not be. The same is true for squares: all sides can be 1 cm long, but the length across the diagonal is 1.41......irrational.


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

[User]
Do successive covid reinfections increase or decrease in severity?

Will they eventually wear-down a person's immune system or prime it to better handle it?

eta...
 I mean an individual who gets it several times, which I guess would include variants.
Particularly health workers who are continually at risk of exposure.
With it being endemic, it's likely we all will potentially get more than one case of it even with vaccination, so with long-covid being a concern, will we all just eventually get weaker and more debilitated till it takes us out, or will we find it less and less of an issue?

[Assistant]
This is honestly a really difficult question to answer now given we have so little data on reinfection and long covid effects.

There are signs pointing to the virus staying dormant / hidden after recovery (ie hepatitis or herpes), and potentially having longer term complications we might not yet be aware of but its still too early to tell.


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

[User] If The Doctor was bitten by a zombie, could he cure himself by regenerating? [Doctor Who]

[Assistant]
There's a question before this one.

Could a timelord even be infected?

Seeing as animals are *generally* not able to get infected by most strains of zombie plagues it seems unlikely any non human DNA including timelord would be compatible.

If they *could* get infected regeneration would likely cure it because the whole reason for regeneration was to revive a wounded or diseased timelord.


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

[User]
[GoT] why didnt the Targaryens ever go beyond the wall?

So Im currently read the world of ice and fire and was wondering why the Targaryens never tried to conquer the wildings? Targaryens ruled Westeros and had dragons for centuries before the dance of dragons killed most of them. Did none of them think it would be worth it to at least explore whats up there? They had been used to dealing with with hostile natives with a home field advantage (the dornish) and seemed comfortable enough with the dragons to fly the long distances require. The least they could do is run a bunch of recon flights from winterfell to get an accurate map of their kingdom. Seems weird they had seemingly no interest in that part of the continent.

[Assistant]
Mostly it's for the same reason the Starks haven't conquered the Wildlings.  It's a lot more trouble than it's worth, they have a massive wall, there isn't a stable governmental structure like Dorne has, and the Night's Watch is an incredibly effective way to dispose of the unwanted.

The dragons can't do recon, they refuse to go into those lands.


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

[User] I want to start reading philosophy books whats the 1 book I should get to start philosophy?

[Assistant] I'd recommend starting with some of the more introductory books on philosophy, like Bertrand Russell's "The Problems of Philosophy." It will give you a good overview of a variety of philosophical problems.


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

[User]
[28 Days Later] Do The Infected Drink?

So I recently watched 28 Days Later, and it was pretty good. However, I was wondering: how do the zombies drink? They clearly don't eat humans or have any values of self-preservation. They can last for maybe a month before starvation (like a normal human) but survive without water somehow... do they drink? They don't eat victims, only kill them, so they don't eat at all. Do they drink and not eat? I would imagine they dehydrate faster since they expel so much blood regularly, which is all precious water.

Just wondering.

[Assistant]
We excrete urine to get rid of salts and metabolic waste products. Clearly the infected are able to tolerate high concentrations of these things in their blood, and they don't waste water washing then out.

They're allowed to violate lots of rules of physiology, but they cannot violate the law of conservation of mass. Fun fact; a lot of people assume that the oxygen molecules that you breathe in end up as the oxide part of carbon dioxide, because that's what you breathe out, but that's not true! Those particular oxygen molecules turned into H2O. In this case, water is waste!

The only viable explanation for something to be constantly bleeding and frequently vomiting is that it has near perfect metabolism that somehow shunts waste water from all these processes in such a way that it can be converted to precious blood and vomit.

Unless they harness some kind of extradimensional matter, this is the only way that they don't end up as angry human raisins.


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

[User]
What actually makes something move along a concentration gradient?

Is this something to do with the probabilities of particle paths, or do particles have some property which I don't know about?

[Assistant]
Microscopically, each particle is undergoing some chaotic thermal motion, which we can model as being random, according to some phase space probability distribution.

The phenomenon of diffusion just results from the simple fact that most particles in the system are moving, and any particle which is moving will be in a different position in then next instant of time than where it is now.

In other words, they're more likely found to be *somewhere else* in the next instant of time.

So on average, this will lead to a net flow of particles in the direction of high concentration to low concentration.


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

[User] ELI5: Why are mid-90s shows like Friends available in high definition, while shows from the same time period (and same network) like Frasier only in standard definition?

[Assistant] It depends on the media used to record the show - traditional film can be rescanned at higher resolution, magnetic media maybe, maybe not. It also depends on how much money the studios think they will make by re-releasing.


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

[User]
[Doctor Who] What's the dalek's plan for after they kill everyone?

So, the Daleks don't seem to have a culture or art or games or relationships or any such thing. All they do is kill people. They socially interact? It's a ploy to kill people. They farm? It's resources to kill people. They scientifically investigate? It's inventing ways to kill people. That's all they do, hate and kill.

So, suppose they succeed. Say the reality bomb from *Journey's End* does in fact go off, as it's probably the most final victory. Everything that's not a Dalek is gone. Even the *possibility* of something not being a Dalek is destroyed. They've won, absolutely and definitely, in every universe.

So...now what?

Do they just deactivate? Do they turn on each other? Do they reinvent art and culture? Do they sit and stare into space for eternity?

The Dalek empire is one big war machine. What does it do one the war is over?

[Assistant]
They go on preparing for war in case they missed something. They eventually diverge until they go to war against each other. They've fragmented into factions before.

The daleks are meant to be alien fascists. Just like real fasists, their ideology is centered on the idea of glorious war. With no one to fight there's no point to them, which is part of why daleks and fasists tend to lose.


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

[User]
[Cool Runnings] That loose bolt

So I am watching Cool Runnings again and I have a massive issue.

The whole finale and the crash and them wiping out is basically caused by that loose bolt right. Yeah the sled was a piece of shit, needed some love ans care.

Now I don't know much about Bob Sledding, but wouldn't a very basic thing to do after every single run be basic maintenance? Like a check of things like that? Of bolts, making sure everything is tight, and oiled, well maintained?

It really bugs me.

[Assistant]
Mostly likely the team did check and perform maintenance on their sled, yes.  Certainly Irv was a knowledgeable coach, and Derice was a conscientious captain, so with their influence it's hard to picture the team skipping out on their maintenance duties.

So why did the bolt get loose then?  Most likely it was due to the sheer age of the sled and the wear and tear it'd been through already.  Team USA had been using the sled as a practice sled, which meant it had probably gone through multiple runs a day for who knows how long.  There's also no guarantee that proper maintenance had been performed on it by Team USA, because again it's just a practice sled.  So there might be minor issues with the sled, such as a bolt's threads no longer being tight enough, or certain parts or cables rubbing against the wrong places during runs, or excess vibrations running through certain parts of the sled when it's in use. However, these problems might not be caught or even detectable during maintenance by the Jamaicans.

But as we see, when you're going downhill at a million miles per hour in a slippery-slidey missile, even the smallest defect can become a major issue.


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

[User]
ELI5: Why are movies all 1.5~2 hours long?

Who decided all movies (excluding short films) would be generally the same length? Why this length in particular?

[Assistant]
It's an average at which a compromise occurs between holding the audience's interest and attention and the feeling of getting value for money paid. Any longer and the brain starts thinking about doing other things; any shorter and the brain starts thinking it's been ripped off because it paid for a certain "duration" of entertainment. A half-hour flick isn't interesting enough to invest in a trip to the movie theater.

Kids movies are usually shorter than adult drama features because younger audiences have less of an attention span and have a much greater sense of the passing of time (which is why rainy afternoons lasted forever and killed us with boredom as toddlers but we barely remember them passing as adults).

All of this can be overridden if you are really into something that immerses you like a videogame, and it's more about averages than about individual watchers.


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

[User]
ELI5: If the Earth has no moon, what would our oceans be like?

There wouldn't be tides as we know them now, or none at all?   Would temperatures and currents be different?

[Assistant] Tides would generally be about two-thirds less powerful, and be much more closely tied to the time of day.  The moon's tidal force would be gone, but the sun's tidal force -- about half as powerful as the moon's -- would remain.


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

[User] Why do I hear ringing/buzzing from certain electronic devices and appliances?

[Assistant]
The devices employ a switch-mode transformer. Basically this chops up the electricity into pulses with a certain frequency(the switching frequency). This frequency may change, depending on the load of the power supply. E.g. whether your phone is charring(heavy load), or if it is done charging but still plugged in(light load).

What happens is that the chopped up electricity runs through a coil/transformer/inductor, which actually physically begins to vibrate because of the magnetic fields created by the chopped electricity that runs through it. If the frequency changes with respect to the load, it may be that the frequency drops into the audible range, thus allowing the coil/transformer/inductor to produce audible noise. If the frequency doesn't change, it may be that heavy load introduces a larger current which again produces a larger magnetic field, which causes more vibration. It can also be a combination of those two.

It is essentially the same sound you hear when you stand next to a transformer station, but there the sound is 50/60Hz because that is the mains frequency. In switch mode power supplies, the switching frequency is several kilohertz, which is why the sound is at a higher pitch.

(im an electrical engineer)


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

[User] [One Punch Man] How are monsters and heroes born?

[Assistant]
Monsters are the result of a genetic mutation that happens when an individual is obsessed with something or have extremely strong feelings towards or about something in some way, always negative. The stronger the obsession and the physical potential of the human the stronger the monster becomes. Some animals have also undergone this type of monsterification

Of course, this is just the most common type of monster. There's also natural monsters such as the Sea Folk and the giant centipedes, organisms that have been subjected to pollution, genetic experiments, people drinking super serums, and people that have eaten Orochi's monster cells.

The super strong human heroes such as Bang, Darkshine, Flash, Metal Bat and Tank-Top Master were born with their potential to become as strong, and has achieved their level through intensive training.


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

[User] ELI5:Since almost all of the water on earth is saltwater, why didn't we evolve to be able to drink it?

[Assistant] There was always enough fresh water around that we didn't have to. Things don't evolve because it would be a good idea, they evolve because if they don't they die. Not being able to drink seawater didn't kill enough of our  ancestors.


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

[User] [WH40K] What is the proper etiquette in the Empire of Man?

[Assistant]
It really depends on who you are, where you are ect ect.

But im going to assume you meant a civilian, which narrows it down a bit. There is still a lot of variation, so this is the general picture. Don't question the emperor's rules, or you'll be killed. Everyone is more important than you.

Thats pretty much the picture,  because the majority of the imperium is kept in ignorance of what is really out there in the galaxy.

I'd love to give a more specific answer but the imperium is so big and varied anything can happen.


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

[User] We know that there are Suns in the visible spectrum, are there suns that exists purely in the gamma or radio ranges?

[Assistant]
As you make an object hotter, the peak frequency of the emitted light shifts towards the higher frequencies. However, the intensity of the source will increase for every given frequency. This means that any object hotter than a few thousand degrees will emit radiation in the visible spectrum, no matter how hot it gets.

I don't know enough about the classification of stars to know if one can be cold enough to not emit a noticeable amount of visible radiation, whilst still being classified as a star.


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

[User] [Marvel + DC] Batman is given the Super Soldier Serum. What happens?

[Assistant]
In the MCU version of Captain America, they said that the Super Soldier Serum brought out and elevated what was already there--- it made Steve Rodgers an all American hunk and made the Red Skull and a super strong.... red skull.

So what was already in Batman? Yes, he'd get peak human physical strength but on top of that, he'd get a sharpening of the mind--- perhaps going from genius level, to human computer level, able to juggle multiple, far-ranging scenerios in his head all at once, to the point he might as well be pychic.

He's insanely prepared *now*-- with Super Serum, he would be a mix between Oxymandias from Watchmen and the Midnighter from the Authority. And yes, he *could* dodge bullets.


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

[User]
I believe that debate over abortion eventually comes down to whether a fetus is a person or not, cmv.

I believe that the principal point of contention with regards to abortion is ultimately whether a fetus has the rights of a person and that other issues are secondary. (In case it comes up, I am pro-choice). I'm not arguing whether or not fetus have these rights, or at what point a fetus would gain these rights, just whether this issue is the central one to the abortion debate.

If one believes that a fetus is a person, then  they would be pro-life. This view would imply theat abortion would be the moral equivalent to murder (except in cases where the mother's life is at risk). All other issues, such as a woman's right to her body would be secondary, as saving a life - forgoing an abortion- comes first morally. Many pro-lifers feel that personhood begins at conception, hence they feel that abortion at any stage of pregnancy is wrong)

If one feel that a fetus is not a person, then they would be pro-choice. Although one might dislike abortion, if one does not feel a fetus is a person, then abortion would not be equivalent to killing someone. In this case, a woman's right to her body would come first.

[Assistant]
>All other issues, such as a woman's right to her body would be secondary, as saving a life - forgoing an abortion- comes first morally.

Legally, the right to your own body comes before somebody else's right to live. You cannot force someone to give up organs, blood, or any other part of their body to save someone else. In this line of thinking, the personhood of the fetus is irrelevant since no matter the answer, a woman can still get an abortion.


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

[User] ELI5: What do viruses/bacteria exactly do inside of our bodies that makes them dangerous and causes us to get sick?

[Assistant]
Just a little additional info:

When you "feel sick" most of these symptoms are not caused directly by the infection, but by your own immune system attempting to kill/flush out the infection.

Fever to kill the infection

Runny nose (increased secretion) to flush out the system

Cough/sneeze. To expel built up secretions and infectious organisms.

In fact allergies are just your immune system reacting to things that aren't pathogens.


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

[User]
Did humans discover or invent mathematics?

Plato said that numbers, as well as all mathematical phenomena, objectively exist, and humans uncover the mysteries of these phenomena. According to him, mathematics is a manifestation of logic itself.
While this view makes sense, and is quite practical, I find that there are some problems with it. Some mathematical phenomena seem to be defined into existence, for example, imaginary numbers and the complex plane. Do imaginary numbers have any relation to reality, or do they exist simply because we've arranged our axioms in their favor?
For that matter, how do we know any of our axioms are correct? We develop axioms because the only way to coherently prove anything with mathematics is by rigorously defining the terms used. But how do we know that our definitions are true?

[Assistant]
>Some mathematical phenomena seem to be defined into existence, for example, imaginary numbers and the complex plane.

How are the complex numbers any more or less "defined into existence" as, say, the natural numbers?


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

[User]
[MCU] How much did S.H.I.E.L.D. grow between "Iron Man" and "The Avengers"?

Although S.H.I.E.L.D. has been around since the 50's, they weren't well known until very recently. In Iron Man, they seemed fairly small-scaled. They had difficulty getting an interview with Stark, and Director Fury himself went to Stark's house to invite him to join them.

But by the time that Avengers rolled around, they seemed to be much larger. And in Agents of S.H.I.E.L.D. they seem to be as well known as any other governmental organization.

Did the sudden rise of superheroes in the MCU cause S.H.I.E.L.D. to drastically expand? Or were they just better about hiding in the past?

[Assistant]
I wound't call it "grow"... it became more visible. At first they were near secrete, they didn't give press releases, no comments, their budgets were tied with some obscure laws that no one wanted to touch, etc.

They were a secret organization in the open. Their offices were modest, their teams small, and they did not used their status to force anyone's hand if it wasn't crucial. You could go and walk in their main office and ask for an appointment with anyone inside. Of curse, their real goals and technological advances were secret, go ask and they were a technological analysis. They did studies and tried to contain potential threatening technologies.

After the first time we saw Iron Man, it was clear that their way of acting wasn't working anymore, and they started making the Agency more public. Within a few months of PR, press releases and whatnot, everyone knew how S.H.I.E.L.D. was.

>Director Fury himself went to Stark's house to invite him to join them.

That was Fury, he likes to hire his team personally.


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

[User]
ELI5: the Yugoslav Wars

This is a piece of history that has somehow always evaded my understanding. It's not included in typical American public school curriculum for some reason, and the touchy nature of the wars make it difficult to find a summary that isn't overly politicized.

[Assistant]
**TL;DR:** Differences of opinion regarding internal Yugoslav politics led to the break-up of Yugoslavia; war between the various peoples within was fuelled by nationalist sentiment and exacerbated by various historical factors.

First, some background information. During WW2, a number of factions emerged in Yugoslavia:

 - The Ustase (pronounced oo-stash-e) were Croat fascists who allied with the Germans, and ruled the Independent State of Croatia. They sought to create an ethnically pure Croatia, and saw Serbs as the main obstacle to doing so.

 - The Cetniks (chet-niks) were Serb guerillas; while the movement was not entirely homogeneous, much of it engaged in collaboration with the Germans and Italians. They sought to create a 'Greater Serbian' state, which, naturally, would be ethnically pure and free of Croats/Muslims.

 - The Partisans were a multi-ethnic resistance force led by the Communist Party. They were the 'official' allies in Yugoslavia, and in addition to the Nazis, fought the Ustase and Cetniks.

Eventually the Partisans won, and their leader Josip Broz Tito became the Yugoslavian president. Despite repression of both by the Yugoslavs - many former Ustase and Cetniks were executed - ethnic tensions remained. However, these tensions were largely suppressed by Tito during his rule.

In 1980, Tito died. At the time, Yugoslavia consisted of six republics: Bosnia, Croatia, Macedonia, Montenegro, Serbia, and Slovenia; and two semi-autonomous provinces (Kosovo and Vojvodina, both in Serbia). Each of these had a vote in the federal presidency. With Tito's death, relations between the six republics began to deteriorate, and the communist leadership began to fragment along national lines. In the late 80s, this was exacerbated by the worsening economy and rising nationalism throughout the country.

Essentially, Croatia and Slovenia wanted greater autonomy, whereas Serbia sought to strengthen federal authority over all of Yugoslavia. During the 80s, the Serbian president, Slobodan Milosevic, replaced the representatives of Kosovo, Montenegro, and Vojvodina with people loyal to him. This effectively granted Serbia four out of eight votes in the federal presidency, along with significant influence over decision making, as the other republics only had one vote. In early 1990, at a meeting of the communist party, Milosevic used this influence to vote down proposals from the Croat and Slovene delegates, causing them to walk out, thus breaking up the communist party.

Referenda were held in both Slovenia (in late-1990) and Croatia (in mid-1991) regarding independence from Yugoslavia. These were overwhelmingly won by the pro-independence sides, leading both countries to declare themselves independent of Yugoslavia. The federal presidency sought to stop secession, with the Yugoslav prime minister, Ante Markovic, declaring it illegal under the constitution.

Here's where the war formally began. Without going into too much detail - this is where the politicisation you mentioned *really* comes to the fore - the Yugoslav Wars consisted of:

 - The Ten-Day War (1991), fought when the Yugoslav army invaded Slovenia to prevent secession.
 - Croatian War of Independence (1991 - 1995), fought between the newly-independent Croatia, and the Serbian population of Croatia (backed by the Serb-dominated Yugoslav army).
 - Bosnian War (1992 - 1995). Effectively a civil war fought among the Bosniak (Muslim), Croat, and Serb populations of Bosnia, each of which had differing desires for the future of a Bosnian state.
 - Kosovo War (1998 - 1999), fought initially between Serbia and Albanian insurgents, with NATO joining the Albanian side in 1999.


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

[User]
[Spider-Man]How come the entire symbiote race copied Spider-Man's Powers?

The entire race seems to have developed powers, not just the ones spawned from the venom symbiote, similar to spiderman. How come all symbiotes share this trait?

[Assistant] They don't really have Spider-Man's specific powers? They are super strong and powerful, and their tendrils can sometimes act as webbing, but their powers mostly result from their gooey semi-fluid nature.


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

[User]
ELI5: How does time "fix" electronics?

Similar things have happened in the past but a week ago my son dropped a stuffed bunny he has that sings, claps its hands and waggles its ears when you press on its foot.  He dropped it on the floor hard and instead of working it would just slightly vibrate until you flipped a hard off on switch.  Tried resetting it a few times and it was still broken.  This morning, a week later my son turned it on and it functioned fine again.

It seems like sometimes, just giving it time will solve problems such as this, curious as to what could be a reason for that.

[Assistant]
Electronics are made possible by metal connections that allow electricity to flow through them. Over time or through repeated use, these metal connections can be corroded and/or lose contact. Normally this ends making the electronics unusable.

However, with random luck, these contacts can reconnect due to some force knocking them back together or through temperature changes stretching or shrinking the components. This is why back in the days, you can sometimes "fix" electronics by bashing them a few times. However, nowadays, the circuits in advanced electronics like smart phones are small enough that this doesn't help. Nevertheless, more simple electronics like the stuffed bunny can sometimes reactivate this way.

A similar thing happens with batteries. You may notice that removing and placing the same dead batteries in a device makes it power on even when previously it was dead. A small amount of corrosion forms between the contact of the battery and the electronics which will stop a bit of the energy. When you remove and place the battery back in, you may end up making a fresh contact, allowing the energy to flow again (though for a limited amount of time).


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

[User] ELI5:Why can't we legalize prostituion simply by filming it?

[Assistant] In prostitution, someone is getting paid to have sex. In porn, two people are having sex, and they are both getting paid to let sometime film them. It's legal because technically no one is getting paid to have sex. They are just getting paid to let people film it.


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

[User]
How does a few people not getting vaccines cause an outbreak of the disease ?

Shouldn't the disease only affect the people that have not got the disease (and may be for those the vaccine isn't that effective) ?

[Assistant] With the vast majority of people being vaccinated, the spread of disease follows Herd Immunity. This is where the people who aren't vaccinated compared to the people who are vaccinated are so few, that the spread of the disease can be stopped/controlled and fizzes out. Once a larger percentage of the population decides to not get vaccinated, than the Herd Immunity starts to vanish, resulting in the ability for the disease to spread to increasing amount of people that are not vaccinated. The people who get vaccinated should be protected against, until a mutation/genetic-drift/-shift/different strain causes the need for a modified vaccination. Hope this answers your question!


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

[User]
ELI5: Where does the term 'ninja' come from if in Japanese it's 'sasuke'? And is ninjutsu something different in Japanese? Sasukejutsu?

I was watching a documentary and it occurred to me that the Japanese-speakers weren't actually saying the word 'ninja'.

[Assistant]
Are you talking about the show Ninja Warrior? That show was called Sasuke. Ninja is a Japanese word, as is the alternate reading, Shinobi. The word literally stems from the character "endure."

There's arguments that there was never really a historical ninjutsu, as a distinct art, but that most of the ninja aesthetic comes from theater, where the all-black outfit originated with stagehands.


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

[User] ELI5: Why does cleaning your ear with a q-tip sometimes cause coughing?

[Assistant]
There's a nerve in your ear canal called Arnolds Nerve which carries touch sensation from the ear canal to the brain. This nerve is a branch of a larger nerve called the vagus nerve, which also has branches in your throat. Because those 2 nerves are connected to the vagus nerve, it's possible (although uncommon) for the brain to mistake where the sensation is coming from, and interprets the sensation in your ear as something in your throat that needs to be coughed out.

That being said, if you're putting anything in your ear deep enough to stimulate Arnold's nerve, you're putting it in \*way\* too deep. You could perforate your eardrum.


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

[User]
[MCU] Did Tony Stark have a contingency plan if Peter Parker had responded violently to his intrusion?

Stark shows up in his apartment, macks on his weirdly attractive aunt, and then reveals that he knows about Parker's extracurricular activities, which kind of freaks Peter out. Did Tony have a backup plan (beyond "get beaten to death") if the kid who could catch a car in mid-air had gotten violently defensive of his secret identity?

[Assistant]
Besides shouting at him to stop before threatening to unleash his Iron Legion on him and his aunt? Probably not much. He'd activate his watch gauntlet device to at least have some defense and offensive capabilities, then stall for time and evade (it helps Peter is trapped inside, lots of obstacles) until he can get some more Iron Man parts. Then he can get outside for some space, and contend with Peter on equal (if not pro-Iron Man) terms.

But he did his research. Peter is a pretty chill kid, and he would either try to lie to Tony about it or he would panic and anxiously demand to know what Tony is going to do with the information or what he wants with him. Peter isn't the kind of guy to flip shit and kill a guy, especially not a fellow hero that's saved the world a few times. You can tell from their interactions in Civil War and Homecoming that Peter sees Tony as an idol of sorts. How could he not? Successful genius who tinkers with tech and also helps save the world? Father figure he never had. Peter wouldn't attack Tony, certainly not full force unless Tony snapped and killed one of Peter's friends or Aunt May. Tony was at very little risk.


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

[User] ELI5: why do our muscles require constant training to be strengthened instead of strengthening them once and having strong muscles forever?

[Assistant]
Our bodies strive to be as efficient as possible in order to increase our likelihood of continued survival.  Muscles, while being useful for motion, are quite expensive energy-wise, so the body only keeps enough muscle to meet the usual requirements for moving around.

Now if you regularly use your muscles to a degree that they get worn out a lot, such as by lifting heavier weights or running longer and farther, then the body builds those muscles bigger and stronger to meet the new requirements and prevent damage.

However, if you stop the additional exercise that built those muscles up, then the body starts breaking them back down because maintaining them costs too much energy and it doesn't seem to need the extra strength anymore.


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

[User] Why is it the governments fault that companies (especially financial ones) are going to collapse the world economy? Are the companies aware of what they are doing? (are THEY even doing it?) Wont they go down as well if the world economy does?

[Assistant] It's the government's fault the financial industry collapsed, and will collapse again, for the same reason it's your parent's fault when you eat too much candy and throw up. Some kids will just keep eating as much candy as they can, because it tastes good and they either don't realize or don't care it'll make them sick if they have too much. Companies are the same way, sometimes all they care about is making as much money as they can right now without thinking about if it's a good idea overall, and it's up to the government to make rules to stop them from doing dumb things right now that will hurt them later, the same way your parents have to help kids eat properly so they stay healthy.


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

[User] ELI5: What is the tiny *crack* that happens when you touch/move just a tiny bit things like TVs, monitors, furniture, doors after they've been untouched for a while?

[Assistant]
If its been there for a while the dust will accumulate right around the edge of contact with the surface its stood on.

The dust gets right into the tiniest gaps as all dust does and over time it gets a little sticky as a result of the temperature and humidity levels changing throughout the day.

This can ve observed by just not dusting some finished countertops for a really long time. They will eventually become sticky to the touch.

The crack you are hearing is the sticky dust seal breaking.


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

[User]
Would it be possible to create a larger scale experiment of a straw holding water?

So if u put something over the top of a straw as it is in water, could u then create the same scene but say 10 times larger. Would this work? would the force of gravity pull it down?

[Assistant]
Excellent question! The bottom surface of the water in the straw (with water above it and air below) would be an unstable surface if not for surface tension. That is to say, although it's in equilibrium (if the surface were PERFECTLY flat and it were in a hypothetical zero-vibration environment nothing would happen), it's subject to something called the Ralyeigh-Taylor instability which means the surface gets exponentially wavier and wavier until the air bubbles up through the water and the water falls out.

So the Rayleigh-Taylor instability would make the situation unstable, but the surface tension of water stops waves/ripples from forming on the surface, making it stable again.

So there is a maximum width for the straw, which you could determine experimentally!


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

[User]
ELI5: Why are universities unable to respond to questions about admission decisions?

I read that at some universities you can appeal the decision.
I got this message that my application to the Masters program was unsuccessful, along with "Regrettably we are not able to respond to inquiries about this decision"

Is it because it is too difficult to reply or they don't have enough staff on hand?

[Assistant]
Both.

If they open themselves up to responding to questions about why they aren't admitting people, they will have to spend a ton of time dealing with upset folks, answering e-mails and finding polite ways to say "We didn't think you had what it took." They'd have to pay someone to answer those e-mails, and that person would need to have the patience of a saint. It's just easier for them to not accept any questions about it.


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

[User]
[The Mist] Why didn't her followers try to save or avenge her?

When Mrs. Carmody begins gathering followers, they were shown to be pretty protective of her and were always around her. When they lynched the soldier, David and his group tried to save him, but her followers blocked the way and held them back.

If her followers were so protective of her and so devoted to her, why did they immediately run off or hide when Ollie shot her the first time and leave her completely exposed? Why didn't they pull her to safety, throw themselves in front of her, or try to stop Ollie from shooting a second time?

When Ollie shot her the first time, he walked up to her and paused for a few seconds. There were 4-5 people armed with weapons: the mechanic and butcher each had huge knives, there was a guy wielding a baseball bat, I saw a guy with a hammer, and I think I saw a woman with a frying pan. Why, during that time where he was paused, didn't any of those people rush at Ollie and try to subdue or even kill him and take the gun away from him?

Even better, after she was killed, why didn't anyone, especially those with the weapons, make any effort to avenge her or stop David's group from leaving the store? Why not sneak up behind any member of David's group and kill them?

They had a chance to at least somewhat avenge her when the store manager ran back and begged to be let back in. They could have locked the door and just walked away or killed him the second they let him in, but no. They squandered that chance too.

Just doesn't make any sense as to why they would protect their beloved leader one moment, then leave her to die and not make any efforts at revenge the next.

[Assistant] Up to that point she had all the power in their eyes. Getting shot by the gun-wielding opposition group is a pretty big power shift. Without her charisma, they were just meek and scared individuals. Sure they protected her from that assault you're talking about first, but when someone whips out a pistol you start thinking of yourself and not as a group with a goal in mind.


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

[User] ELI5: Why do people with dark skin have lighter skin on their palms and the soles of their feet; and yet not in other places devoid of sunlight: scalp, armpits etc.?

[Assistant] The difference is not due to sunlight, but skin thickness. The skin on your palms and feet is fundamentally different than the rest of your body, because we use these surfaces to perform numerous physical tasks. So the skin there is full of extra protein called "keratin" that makes it much thicker and durable. It also makes the skin appear much lighter.


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

[User]
[Dr who] If the doctor alone is so powerful why did the timelords never conquer the universe?

We know they are militaristic and the doctor himself destroyed whole armies of daleks by himself so wouldn't it be easy to dominate everything?

[Assistant]
Because they already control the universe.

The Time Lords of Gallifrey are not threatened by anything short of the entire Dalek armada.  That means everything else in the universe - the Judoon, the Weeping Angels, the Zygons, the Cybermen - dealing with them would be as much effort as swatting a fly in comparison.  At the peak of their power, there was nothing the Time Lords did not or could not know, there was no achievement they had not accomplished, and as previously mentioned there was only one race in all of creation that could stand up to them.  And when the Daleks finally did come to call, they had to push the universe to its absolute breaking point to succeed.  *That* is how powerful the Time Lords are.  And none of this even begins to get into the Time Lords' biggest schtick; their unrivaled mastery of time travel.  Much like the Great Intelligence once did on a smaller scale, every battle was a guaranteed victory, every war destined to end with a Time Lord victory.

The Time Lords don't fight for control of the universe for the same reason you think nothing of pouring water down an anthill to make room for your new patio.  Not only have they already won before the first shot is fired, actually firing the shot would be almost insultingly easy.


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

[User]
How to determine what am I?

I know that my character traits, decisions I make, my hobbies, likes, friends, job, home and everything else around and inside me could be temporary and aren't fixed through my entire life. Thus, it wouldn't be correct to think of myself as a set of these temporary preferences.

In the meantime, there is something I'm driven by, some force inside me that pushes me and helps me make decisions and take actions. Is it just complexes, insecurities, my ego that is trying to achieve something and fulfill its (or my own) needs? I don't really like the idea of thinking about myself as a bunch of anxieties, doubts and stresses, even though from scientific point of view we all are just bodies with some biochemical reactions going on.

So, has anyone figured out how to explain to answer yourself a question "what am I?" or it's impossible to answer until your last days of life when you have a full perspective of the life you've lived (this is just one of my assumption of how you can get to know yourself)?

Any related articles, videos, books are appreciated.

[Assistant] A question like that takes a lot of meditation and sorting through complexities and intricacies of your identity.  Simone de Beauvoir describes her realization when she told herself "I am a woman", a statement which seems so obvious and yet was so impactful to her identity and development as a human being.  Instead of searching for books, articles, videos, and hearing what other people say, look inside yourself.  It could take months of quiet time & long walks, but it'll be worth it.