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

[User] ELI5:Why, in most of the animal species, only females take care of their offsprings?

[Assistant]
A lot of animals do have the females raise the offspring, others have both help, or just the male, and others still just lay the eggs and abandon them.

As to why these strategies develop: the simple answer is that it works in regards to the environment they live in. Something to understand about animal evolution is that "survival of the fittest" isn't necessarily about being the biggest, baddest, toughest creature out there and not "fit" in a exercise-y sense, but rather that animals evolve to be the best "fit" to their environment. This can include size, teeth and claws, and brainpower, but it also includes things like social dynamics, integument like feathers or fur, and reproductive behaviors. Because, at the end of the day, an animal could be aggressive and dominant but it's not going to be "fit" to it's environment if it can't reproduce successfully.

First of all, the ancestral strategy and most popular for animal reproduction is the hands-off approach: where the young as eggs are released en masse into the environment to fend for themselves and a few make it to adulthood. This has the obvious disadvantage of most of your young being eaten and you wasting resources, so over time some animals may have started taking care of their young, laying smaller clutches of eggs, and eventually, in some cases such as some sharks, snakes, and mammals, hatching and nurturing the eggs inside (usually) the female's body and giving live birth. Now, with the advantage of your young being more likely to survive to adulthood, you're stuck with the disadvantage of them requiring many more resources from you to raise, so then you start evolving different strategies to minimize effort and maximize offspring that make it to adulthood in your environment and according to your biology.

For example, with songbirds and pigeons both parents incubate and feed the young as they grow rapidly. The eggs they lay are often very large compared to the size of the female and take a lot of nutrients out of her. But with jacanas (a family of wading birds), the female lays several clutches of eggs with different males and the males raise them while she wanders around protecting her territory. She's thought to be able to afford this because of how rich the food and calcium gets during their breeding season. On the other extreme, megapodes (in the same clade as chickens and quails) simply lay their eggs in mounds like crocodiles do and the eggs hatch fully flighted and ready to take care of themselves, even though they do go a step above the ancestral behavior and guard the mound.

So it's mostly about what works in the environment and how much the parents have to invest into creating their young in the first place. It's possible that female mammals especially might have more interest in their young because of how demanding pregnancy is on the mother. Males join in or females opt out according to what best "fits" the environment and the demands of the young.


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

[User]
My GF won't wash fruits or vegetables before eating them.  I think she's gambling with our health; she thinks I'm paranoid.  Who's right?

This morning she cut up strawberries and dropped them on her cereal without washing them.  All I could think about was the trace bits of dead bugs, pesticides and fertilizer she must be eating...

Edit: Wow.  This sure struck a lot of interest.  Thanks for the input!

[Assistant]
As someone who worked in produce for four years while slaving through college, wash everything you buy because stuff happens to it that you don't want to know about.

As someone who did food microbiology research for a few years, washing it with water won't get rid of things like bacteria and pesticides anyway. It just removes surface dirt and particles like that. If you really want to be paranoid about your food you should buy that vegetable/fruit cleaner that you dump in a bowl of water and soak the stuff in, but again, doesn't really do that much.


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

[User]
[Star Trek] Does the general public know that time travel is a thing? If so, what are the philosophical implications of everyone knowing that they live in a deterministic universe with no free will?

Like, what was the official story told to the average Federation citizen about how Captain Kirk and his crew managed to find a bunch of whales to call off the alien probe? Gillian Taylor presumably lived happily ever after in the future, but did the Federation leadership allow her to tell the real story of where she came from?

I can't imagine that the existence of time travel is something any government would want the general public to know about.

[Assistant]
TNG *Parallels* (plus the Mirror Universe and TNG's *Yesterday's Enterprise*, and the entire Abramsverse) implies an infinite multiverse of branching decisions, and DS9's *Trials and Tribblations* shows us that the Federation even employs rather droll and mundane HR-like officers who debrief crewmen after (or technically before, depending on the nature of the time travel) incidents of encountering time travel or temporally-related artifacts like the Bajoran spheres, so knowledge of it is likely common, though more applicable knowledge on *how* to do so is probably highly classified.

How then does this gel with the 29th century Federation timeships and temporal police trying to keep the timeline on track? Well, the existence of a multiverse which branches with each of our decisions (TNG *Parallels*) implies that for every universe where the time cops stop something bad from happening to what they perceive as their distant past, there is another branch where they failed to intervene.


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

[User]
[Skyrim] How do the Stormcloaks hold Markarth?

So the Empire and the Stormcloaks called some kind of truce so that Dragonborn fellow could go stop the dragons. But the Stormcloaks got control of Markarth as part of the deal.

Now that Alduin was defeated and the war resumed, how do the Storncloaks keep control of Markarth? There's half a province between Markarth and Stormcloak territory. Markarth is also surrounded by Empire territory held in Skyrim and Cyrodill to the south. Is the Empire not powerful enough to siege it from all sides and regain control of it?

[Assistant] One of the guards (or maybe the Jarl) says that Markarth is one of the easier cities to defend due to being built into the mountain and has dwarfen made gates, sure, they're talking about defending from dragons, but if you're not scared about dragons, you're hardly going to worry about human soldiers.


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

[User]
[Attack on Titan] Congrats! As Vice Commander of the Southern Division of the Garrison Corps, youve been tasked with coming up with a plan to stall the Titans advance into Trost District and keep the civilians safe until they can all be evacuated. Good luck!

Commander Pixis is currently very ill and wont be fit to lead the troops in defending the retreating civilians and slowing down the Titans advance.

As Vice Commander of the Southern Division, youre now tasked with this monumental responsibility. Fail and youll be demoted to a lowly common soldier. Whats your plan, sir/maam?

Personally for me, before the Colossal Titan even showed up, Id order for some of the land outside of Trost to become a heavily militarized no-mans land. Id also order for the small strip of land bordering the outer gate within Trost itself to be turned into an authorized military engagement zone where artillery fire and explosives can and will be used. More of those wooden defensive barriers shown in the anime will be made, with many standing by.

Assuming that the Titans are arriving fast, artillery units at the breached gate will fire for as long as possible in order to delay the Titans and for there to be an actual military presence within the city, as well as the evacuation of civilians. The aforementioned wooden defensive structures will be moved strategically in order to block roads and alleyways which Titans may utilize. The plan isnt to stop the Titans, but to merely slow and contain them. If the defensive barriers are doing their job, they should slow the Titans down enough for reinforcements to arrive, keeping them near the gate.
Advance combat teams will also go over Wall Rose to engage the Titans if need be, however, they will only engage in combat if Titans are actually at the gate.
If the Titans have made it through the gate and hugging the defensive barriers, troops will have to deploy ASAP.

In my spin to the original Colossal Titan breach plan, I will order for troops to amass right at the vanguard in order to pack as much of a resistance against the Titans as possible. Meanwhile, assuming that civilians are still being evacuated, cavalry units will be deployed via lift/pulley system off of the wall and be used to distract and harass the Titans outside of Wall Rose for as long as possible.
While the majority of Garrison soldiers will be at the vanguard, the Trainees (under Garrison command and supervision) will split into 2 teams and stand by by the flank, allowing for an orderly and tactical retreat of the vanguard (personally, I thought it was stupid for Trainees to be responsible for the Middle Guard since they just graduated training literally days ago. They werent experienced enough and shouldve had reserve Garrison troops lead/monitor them instead of having them be independent of any official military command structure. In the real world, youre not going to send new Marines who graduated from boot camp less than 72 hours ago onto an actual combat deployment. Then again, Marines dont have a 2 year long boot camp geared towards fighting giant naked creeps).

Anyway, speaking of a retreat, civilians should be evacuated within 2 hours, and assuming that things work out perfectly with the civilians, the vanguard should slowly retreat into the middle while the rear guard comes in to help assist, forming another massive body of soldiers and Trainees to engage the Titans. Artillery units will also be permitted to use artillery within the city in the former vanguard area in order to pick off hordes of Titans, forcing the Titans to be attacked in the front and rear. If cavalry forces havent been wiped out, theyll be used to enter the city utilizing a combined arms strategy with wall-mounted artillery units.

If civilians are still evacuating after 2 hours, squads of elite Garrison soldiers/Trainees in the rear guard should be deployed as floaters into the city. If things got *really* bad, a controlled and orderly retreat should be conducted from the vanguard and into different sections of the city, forcing Titans to split and move in clusters.
Speaking of civilians, in order to get civilians out of there ASAP, the pilot system used for the cavalry units should also be used to bring people across the Wall.

Logistics and supplies should be spread out throughout Trost in multiple fortifications with personnel manning them at all times. They should have artillery of their own and should be fortified enough to hold off a Titan siege. Trainees will be responsible for guarding and assisting these logistics/supply depot/forts, as they are extremely vital to the battle.

[Assistant]
First: whatever nut jobs thought it would be a good idea to assault the titans in hand to hand combat while flying around like a drunk spiderman, should be fired. Their reckless attitude will be a detriment to unit cohesion.

Second: Guns, lots of guns. Big bore is preferred.

Third: If the titans get passed that, wall of pikemen. Research tells us that titans have the same mass as normal humans, it's just blown up larger. Thus they have low density.  A few dozen pikemen in close formation with long pikes should have no problem skewering a titan, dragging it to the ground, and chopping him up like sushi.

Finally: For specialty titans, Molotov cocktails. Is the titan armored? Large rounds coated in a steel jacket fired at super sonic speeds. If it can punch through iron plate, it can punch through a titan. Or at the very least knock it on its ass, where you can proceed to pour burning oils all over it.


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

[User]
How exactly can e^i*pi = 1?

I asked this from my math teacher and she said that until I have gone to university to study math I won't understand it. Is she right, or can you explain it?

[Assistant]
The series expansion of sin(x) is x-x^3 /3! +x^5 /5! -x^7 /7! etc. ! is factorial, so 5!=5x4x3x2x1=120

The series expansion of cos(x) is 1-x^2 /2! +x^4 /4! etc

The series expansion of e^x is 1+ x+ x^2 /2! +x^3/ 3! +x^4 /4! etc.

i^2 = -1

If write out e^ix this way, you'll see that the even powered terms gets a plus or minus 1 (from i^2 i^4 etc) and the odd-powered terms get a multiple of i. Collecting terms, you'll find e^ix = cos(x)+i sin(x)

Substitute x=pi into that and see what happens.


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

[User]
ELI5: How do hotel booking websites like Trivago or Expedia work? Why are their prices cheaper than when you book through the hotel?

Is this a scam? Or are these websites legit? If so how are they so cheap? Does anyone have experience with booking through websites like this?

[Assistant] The websites are legit and they get paid commission by the hotels, because they are handling millions of bookings their administration and advertising costs per booking are tiny in comparison to the hotels so they can have cheaper prices.


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

[User] ELI5: Every year, all your favorite TV networks produce pilots that never air. Why do they not release these online? Wouldn't it be easier to gauge what their audience wants that way, and possibly monetize off their "failures" as a failsafe way to make some of the money back?

[Assistant] Several reasons.  Firstly, there could be copyright issues. Secondly, often times the ideas in those pilots are cannibalized into another show.  Thirdly, how would they make any money off of releasing it for free? Fourthly, releasing terrible things can dilute their brand and make them lose respect.  Fifthly, pilots are often widely different from what ends up being made.  Releasing it can poison the perception of the public and make the show do terrible.


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

[User]
ELI5: UV Index - How is it measured?

"**The UV index is defined as the effective irradiance on a horizontal surface..."**
I bought a UV Index meter, and the measurements don't match the definition above. When I put it on the surface level, the measured UV index is lower than the reported. I can only get the reported value when I point the device directly to the sun! This completely makes sense to me, because otherwise, the reported UVI would be much lower to vertical objects (aka humans) than the realistic one when the sun is at a low angle, and vice versa. Does anyone know what is the truth?

EDIT: stop upvoting, the answer was too obvious, aka the question was stupid. Big thanks to /nalc!

[Assistant]
The horizontal surface in this definition is the horizontal surface of your UV sensor, with horizontal meaning that it's pointed directly up at the sun and not at an angle towards the sun.

Pointing it at objects will essentially measure UV emissions from the sun times the reflectivity of the surface (which is not necessarily the same in the UV as it is visually). So unless it's a really shiny mirror it will be less.


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

[User]
ELi5: How does fostering kids work?

I always hear about how foster kids are sometimes abused and I want to know what the foster system works. Is it a job or do people get chosen like they do for jury duty? Is it volunteer work, and if so, why are there so many people volunteering to abuse these kids?

[Assistant]
You sign up. Social services does some routine investigations to qualify or disqualify you. Then then place a child with you...and you get a monthly stipend of $600-800/mo plus some amount of foodstamps to feed the kid.
Theres a caseworker assigned to you that has waaay too many foster kids to pay proper attention to each case. When theres a complaint or problem they respond and evaluate whether there is an actionable issue or not.
Abuse happens sure. BUT most foster parents take good care of the kids they foster. Most kids in foster care are a lot better off than they would be in group homes. Like anything you hear more about the failures and flaws than the success stories.


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

[User] ELI5: How come you have to pay for data on your phone, but the GPS in your car is free?

[Assistant]
GPS is a receive-only technology.

A GPS unit does not need to transmit any signals to determine its location, it need only listen for satellite signals or 'pings' that are constantly sent down to earth from satellites in orbit.

The GPS unit uses knowledge of each satellite's precise location in orbit plus the timing of the pings plus the speed of light to determine how far away each satellite is from the unit. If the unit can receive pings from enough satellites, it can pinpoint its exact location through triangulation.

The reason why you often need data for GPS on your phone is that the maps are loaded from a server in real-time as you move to a new location whereas with a standalone or built-in GPS unit for a car, the maps are all pre-loaded into the system.


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

[User]
[Star Wars] Which capital ship gun emplacement type is predominant, shielded gun port, casemate or turret?

Yes, I need a bigger nerd than me to have watched and read more of the Legends stuff.

And yes, I'm wondering why SW ship design is at 1920s level of advancement.

[Assistant]
Casements are predominant for secondary battery, main battery turbolasers are usually mounted in  turrets, to reduce the overall number needed. Frigates will usually only carry casement mounted armament, due to the restricted space. The Republic and the CIS used destroyers with their main battery mounted in shielded gun ports, but it was less useful than originally planned on the Venators and the Empire converted those mountings to anti-fighter batteries.

Long range gunnery (which killed off casements in real life) isn't really possible with turbolaser technology, as the power dissipation at range is so severe. Battles between capital ships are usually fought at "knife-fight" ranges which prioritize rapid fire to overwhelm shields, and reserving the biggest guns for the coup de grace. Although, the Rebel Alliance relied more heavily on torpedoes than turbolasers when it came to finishing off disabled ships; torpedoes were simply cheaper.


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

[User] [MCU] What information would Friday be able to dig up on Dr. Strange and his organization if Tony asked?

[Assistant]
As far as datanets concerned, Doctor Steven Strange was a renowned neurosurgeon, who dropped off the grid after a horrible accident crippled his hands. He sold most of his possessions and last time he was seen properly was on a plane to Kathmandu.

Sightings after this are spotty and unreliable, he completely vanished for months, then was spotted by street surveillance cameras in New York, and not long after in Hong Kong \- there's no information how he could traverse such distance in such little time.

Doctor Steven Strange is not known to be a member of any presently standing registered organization.


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

[User] ELI5: Why is water wet? (actually been asked this by a 5 year old today).

[Assistant]
Water,loves physical contact. When water is nearby a surface, tiny bits of it cling to that surface. Think of it like how you rub a balloon on your head then stick it to a wall. Water is like billions of tiny balloons, like a little ball pit. Imagine if all the balls in the ball pit were like the balloon, and the balls stuck all over you when you got out.

Not all liquids are as thick or sticky as water. That is why water is so wet, because the little particles like to stick to things. Some things like skin, clothes and towels have lots of little bumps and cracks for water to get into, so it does!


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

[User]
ELI5: how does a (formula 1) car wheel spin without much resistance?

Currently watching F1 and seeing those wheels spin super fast. I'm really curious how the wheels and axels, which hold all the weight of the car, don't wear that quickly. Same as in regular cars.

[Assistant]
Each part in an F1 car is built to precise specifications in not just weight but also mileage. Parts are usually made of high strength, low weight materials like titanium and carbon fibre. And they get swapped out during pitstops and over the race weekend.

So they don't have to last for a long time, or even an entire race weekend. Unlike a family car where parts are built for endurance rather than performance.

P.S. Great start to the race, but looks like it's settled down to the usual fare now.


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

[User]
ELI5: How are things rated on the Scoville scale?

I get that it has to deal with capsaicin concentration, but isn't spiciness subjective? Also how do some hot sauces have a higher rating on the scale than the peppers they make the hot sauce from?

[Assistant]
Originally the scale was a measurement of how much sugar water was required to be mixed with the spicy thing before you couldn't detect the spiciness anymore. But, as you said, this doesn't work very well because people have different detection levels. Even the same person will have different reactions over time.

So, eventually they defined pure capsaicin to be 16 million Scoville units. Now they just measure how much capsaicin is in the pepper or sauce and multiply that by 16 millions. For example, if a hot sauce was 5% capsaicin it would be 16 million x 0.05 = 800,000 scoville units.

Hot sauces can be hotter than the pepper they're from if they concentrate the sauce by removing water but leaving the capsaicin.


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

[User]
[Batman] Where does Batman draw the line in the kinds of technology and tools he uses?

I Bruce seems to apply his keen mind to both old-school tools and highly developed technology for his caped-crusading.

Outside of a personal creed and aversion to firearms, where else does he draw the line?

He seems adverse to magic and alien technology, but wouldn't he be more effective if he adopted the more parts of these tools? I means he works beside aliens and spellcasters on a regular basis. He may not openly collaborate and share notes, but Bruce's intellect sounds like he can work out lots of this on his own.

[Assistant]
He's adverse to magic and alien tech since its not well understood or relies on more nuance than he wants to rely on while on mission. You know the 80/20 Rule? Where 80% of the results come from 20% of the prep. Bats is a prepper to the extreme so he has to be efficient and selective on the tools he uses, especially since his life may be on the line every night. Wouldn't be good if the hydraulics on his powered suit failed during a fight with Bane, after all.

And to be fair he does use small amounts of both sometimes, he just doesn't rely on it, and much of his study of both is based more around the goal of having ways to counter it.

And in 2 futures (Batman Beyond and Kingdom Come), Batman does eventually start to lean more on advanced tech as he ages. For Batman Beyond, this means the batmobile and jet are combined and his suit features Ironman-esque qualities, including active camouflage. And in the latter universe he controls a swarm of quasi-humanoid robots which patrol the streets in his stead, and he constantly wears an exosuit since his joints have been pretty beat up over the years.


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

[User]
ELI5:How do the Japanese not smudge their letters when writing from top to bottom and right to left?

Right-handed people would get ink all over their wrists.

[Assistant]
Keep in mind that it's top to bottom first. One column is analogous to one line in western text. So by the time you get to a new column the ink at the top has dried.

On top of that, traditional style top to bottom writing is usually reserved for formal situations (and manga for some reason, but that's mostly printed these days) so you'll be being more careful with your text. Everyday Japanese is written left to right, same as with western text.


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

[User]
ELI5: How do the lungs get cleaned from dust that managed to get there?

So assuming I'm in an environment with a lot of dust (or any other particles) in the air and breathing it all the time.
I guess that most of it are being filtered by my nose and breathing tunnels but small fraction will eventually make it all the way to the lungs.

I'm curious how the body gets rid of that "grabage" in the lungs? Does is it stay there forever?

[Assistant]
your lungs have little hairs inside called cilia, they brush all the crap up.

They basically get rid of all the dirt.

Funny fact, smoking kills them, so you get even more crap in your lungs and when you stop smoking for a week or so and they regrow, they start removing crap from your lungs, so then you start seriously coughing.


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

[User] ELI5: Who determines the rating of a hotel ? and based on what ?

[Assistant]
At least in Europe, star ratings are mostly based on what services/facilities/'minimum standards' they provide. It's not an indicator of quality, but what they have to offer "on paper".

Airco, Telecommunications/Internet, bathtub (seperate from shower), Parking, 24h reception, minibar, roomservice etc... could all be super crappy, but they will still score lots of points for the hotel if they have it available.

Having said that, most of the time, quality goes hand-in-hand with offering lots of services/facilities though. Occasionally - and in some countries more so than in others - cheap hotels will still have lots of stars but offer bad/mediocre quality. Therefor, don't expect a  really cheap 4/5-star hotel  to provide excellent quality. The photos may not match the reality.


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

[User]
ELI5: How does dating work? What are men supposed to do?

So say you have someone's phone number. Then what? Everyone says "it will come naturally" but I don't know what the fuck they are talking about. I'm 23 and I feel like someone was supposed to explain how this works.

[Assistant]
First date? Go out for coffee, a beer or whichever drink you prefer. Don't overdo it. The "just be yourself" thing is a clich but mostly true, except when you're just looking for a one-night-stand. Sometimes you'll be disappointed and sometimes it'll be awesome, not all dates work out, too bad, try again.

Extra info: Expect to hold in your farts subconsiously and when the date fails, you can find happiness in letting those farts escape.


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

[User]
[DC] How is it that no one recognizes Diana Prince as Wonder Woman when she goes around without a mask as a superhero, or without glasses as Diana?

[Possible 1984 spoilers ahead]

With Clark Kent, his glasses keep his identity icognito. With Bruce Wayne, Batman wears his cowl. But Diana wears nothing more than a crown. How is it that no one notices the similarity there? I've found an article going over how Wonder Woman kept herself incognito between 1984 and the Dawn of Justice (apparently used the Lasso of Truth to keep herself hidden even when she used the camera array to broadcast her face) and the fact that she knocks out cameras before taking out the baddies, but there are historical pictures of Diana as Wonder Woman as well. I'm sure that someone somewhere must've caught her on camera between 1916 and 2016.

[Assistant] It's pretty much the same as how Tony Hawk has a hard time being recognized as Tony Hawk when not actively riding a skateboard; devoid of context, people are more likely to assume casual resemblance than actual person, especially when it's someone famous.


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

[User] [Mass Effect] Can Asari reproduce with *any* other species, even ones normally considered 'just' animals?

[Assistant] No they can't. Asari can only reproduce with a species that has a sufficiently complex central nervous system. When melding or joining, the asari joins attunes her nervous system to her partner's and uses that to randomise the second set of genes to be passed on to the offspring.


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

[User]
would a flag on a flying spaceship flap or would it stay in the same position?

sorry for the badly worded question, but I'm half cut and will forget my question by the morning :)

[Assistant]
It would move during the initial acceleration, not due to the passage of air (as flags do on earth) but due to inertia while the ship is being accelerated.

If you think of the direction of acceleration as "up", then during acceleration the flag would hang "down", lagging behind the ship. Incidentally the occupants of the ship are subject to the same inertia and would experience the acceleration as if it was a gravitational pull downwards.

When the acceleration stops, the flag would move again, as tension in the material is no longer being opposed, pulling the flag towards the mast. When the ship is not accelerating, internal friction will slow the movement of the flag until it is still.


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

[User]
[DC] Why is it that whenever a DC hero kills a villain, they always end up going down a path to villainy?

It's like no matter how justified they are in killing someone, they're automatically evil. They're shunned and reviled by their fellow heroes and are immediately destined to descend into madness and at times, dictatorship.

What gives?

[Assistant]
They dont.

Wonder Woman, for instance, executed Maxwell Lord and all she faced was some of her teammates being dicks and a quick trial that found her fully justified. No madness or evil, the entire time she was adamant that her actions were completely justified. To the point where she insisted on the trial, despite her very easily being able to tell them all to piss off.

Superman straight up executed Zod and his cohorts after they were de powered and suffered no fall from grace. Just nightmares.

Hawkman kills fairly regularly, Aquaman can and will put his enemies down, Green Arrow hunted down and murdered Prometheus for revenge, Damian Wayne has a decently sized body count given that hes like 10, Jason Todd doesnt use those guns for show, Starfire will vaporize an enemy if provoked enough, Flash has killed Zoom repeatedly(Which is how he learned the guy was immortal), and so on. Hell, Constantine has killed an entire Earth and remains a hero. Well, as heroic as he normally is.

Quite a few heroes kill, it just only becomes a big deal when said killing is when they are skipping down the path to evil.

Injustice, for instance, has Jokers death as the START of Supermans fall but hardly the cause. The cause was Loiss death breaking the guy while Batman was being an absolute ass and that universes Wonder Woman was MUCH darker than the mainline one and was a terrible influence. It took quite some time for Superman to get corrupted to the point of casual execution, time and a full mental collapse.

Note that while BATMAN treats killing an enemy under any circumstances as the WORST THING EVER, Batmans also nuts and way more hung up on the No Killing rule than anyone else. In that hes one of the very few heroes who actually has that has a hard rule. The rest are on the We arent judge, jury, and executioner stance. Where executing an enemy is a big deal and not to be done on a whim. But also allowed in certain circumstances, such as protecting others.


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

[User] ELI5:How is Snapchat valued at over $30 billion but they have a loss of $500 million last year?

[Assistant]
A valuation is the total value of all the shares of stock issued, based on the current trading price. The valuation is not based on anything else.

The trading price reflects what investors are willing to pay to own that stock, presumably because they believe their investment will be worth more in the future. Many companies that are not profitable have high valuations. This reflects that the investors have faith in the company _in the long-term_.

In other words, investors are not buying stock in Snap because of what it did last year; they're buying stock in Snap because of how they believe the company will perform over the coming years.


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

[User]
[wreck it ralph] Is there more than one Ralph?

If there is more than one arcade console in an arcade is there more than one of a character? What would that be like?

[Assistant]
There's more than one Wreck-It Ralph, but there's only one *Ralph*.

When a cabinet gets plugged in for the first time, all the characters are "born". At this point, all the characters have personalities identical to that of the roles they play in the game. Ralph was genuinely pissed the first time the game was played. This is how characters learn their programming: The first few times the game is run, it's all real. They're just acting as they want. Since they're all carbon copies of the character in the game's plot, the way the act is the same as the game's plot.

Over time, though, the characters grow. They form their own personalities based on their experiences outside of the game. The Ralph you know was ostracized by the other members of the arcade, and grew to despise his role as "bad guy".

If another Fix-It Felix cabinet was plugged in, it's entirely possible that the new Ralph be treated differently by the other characters, and would grow to be a completely different person. Both Ralphs would look the same, but the way they act wouldn't be similar at all. Their code is the same, but everything else is unique.


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

[User]
CMV: Rsum's should contain tenure lengths rather than dates to avoid discrimination

Having recently helped a few former colleagues with job applications, it occurred to me that a simple "fix" could help eliminate a few forms of discrimination.

Common practice on a rsum is to list prior work and education experience with _dates_, e.g. "I was employed at company X June 2012 - May 2015", rather than (or in addition to) tenure length, e.g. "I was employed at company X for 2 years, 11 months".

I think this is problematic for (at least) three reasons:

1. Age discrimination. It is illegal (in the US at least) to discriminate against someone for being too old, and (in my state) it's even illegal to ask about age or leading questions (or if not strictly illegal, legally discouraged). However, by listing the years you attended school or had a first job, it's impossible to ignore age. Of course, you might be able to infer age by looking at experience (e.g. if you worked on a really old technology) or just total number of years, but I hypothesize that this would have a less negative effect. It would look like having a lot of experience, whereas seeing "graduated class of 1980" and then you think "wow that was before I was born" I think you (as a hiring manager) may be more likely to have a negative feeling associated with age here.

2. Gaps due to extended medical leave, e.g. raising children for a few years. A huge problem facing some professional women today who want to start families is getting back into the job market after a several year gap. I personally have heard from a few people who face this, and even if you've kept your skills up to date as best as possible, getting that first job after a gap can be super hard. Same if you had medical leave (physical or mental) or a gap due to caring for a family member. Or imagine you spent a year in prison falsely convicted and then were released and expunged of wrongdoing (don't want to derail this CMV to be about prison / criminals, just an example). By listing years of experience rather than dates, these gaps will be invisible at first glance.

3. The ability to leave off "bad" or "embarrassing" experience. Depending on the field, sometimes a resume can get dragged down by a bad name. E.g. imagine if you were some rank-and-file attorney at Enron or Lehman Brothers. Chances are you had nothing to do with the massive problems that happened there, but it could seem like a black mark. Or, maybe you took a job working tech support for a porn site and would rather leave that off your resume. In any of these cases it's probably not OK to lie to an interviewer about it, but not having it on you resume which is often a first impression could be a huge help. Resumes already don't need to be comprehensive (especially if you have a lot of experience and want to fit it on one page).

As far as how this should be achieved, I don't really want to get into a big policy debate but I think a reasonable step might be a law making it illegal to require exact dates, or at least just making it common / encouraged practice to use (only) tenure lengths instead.

Theoretically, people could just start doing this now, but without some kind of legal backing or at least making it a common and well-known practice, it wouldn't fly, especially when someone is in the (often) vulnerable position of applying for employment.

I also think there are some caveats here, for example if your employer needs to run a background check they might need to know your graduation or employment dates for confirmation (though I think that could fundamentally be avoided too, but confirming tenure lengths rather than dates). Similarly, as said above, asking about types of technologies or coworkers or anything like that during an interview might reveal information about dates, or perhaps past employers all need to be disclosed on a form during reference checks. That's fine, I think, but I still think they should stay off the resume to avoid tainting the initial impression of the interviewee.

EDIT: if a law were passed, it should be illegal for the _employer_ to ask for demand dates, no penalty for the employee (i.e. all existing resumes aren't suddenly illegal).

EDIT2: clarified my pregnancy example to be a few year gap rather than just the weeks of FMLA leave.

**tl;dr: by leaving the dates off a resume, discrimination due to age or gaps at first sight might be lessened. The dates aren't a secret, but maybe don't belong on the resume**

[Assistant] Wouldnt this make it more difficult to verify employment? Another thing to consider is companies have good times and bad. Hiring someone who was in a position that was responsible for bad times is very different than hiring someone from the same position during that companies good times.


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

[User]
What is the expected economic impact of Santa's global distribution of toys made with magic and free elf labor?

I assume Santa uses magic to conjure up the materials needed to manufacture the various toys.  I also assume his elves work for free (maybe they get some room and board, but that too is provided via magic), and they can perform specialist tasks, like forging microchips for game systems, etc.  His reindeer also serve as a super efficient global distribution network, so he doesn't need to hire any deliverymen or procure any delivery services.  With all these presents being delivered to Christmas trees around the world without contributing anything at all to the global economy, what economic impacts can we expect?  Mass unemployment?  Commodity crashes? Deflationary pressure?  Inverted yield curves?  How bad is it going to be?

[Assistant]
Santa drives the price of toys and manufacturing labor down each Christmas. So the supply curve shifts right. Christmas however temporarily increases demand, so there are higher goods supplied at the same price point.

Since Christmas has been going on for years predictably the market expects it and corrects itself in small increments, so there are no large changes to the market.

After Christmas demand for toys goes down, and the labor supply from the elves will not be seen till the next year. This is a bit hard to track how much they are paid because it appears Santa collects payment in milk andcookies. We need more research and need to index cookie prices. Further we would need to take into account store bought vs home made, the amount of cookies supplied per household, and type of cookie.


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

[User] In what ways do sperm change as someone gets older? Or will a 15y/o produce basically the same offspring as a 60y/o (disbarring fertility issues)

[Assistant] Consistency may change with aging and prostate either making more or less seminal fluid. Sperm are made all throughout life. It's possible that a random genetic mutation could happen sometime through life that would change the genetic makeup of the sperm as well (lead apron at the dentist) depending on hormone levels of FSH and LH the count of sperm in semen could change as well.


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

[User]
Why does gravity make planets and stars spherical but galaxies thin disks?

Also, is there a standard shape to super clusters of galaxies?

[Assistant]
Hydrostatic equilibrium. Stars and planets are supported (prevented from collapsing) by the physical pressure of the solids or fluids that make them up. Galaxies, on the other hand, are prevented from collapsing by the velocity of their component stars-- each star is on an orbit around the galaxy. Disk galaxies form out of collapsing clouds of gas (just like solar systems do), which always form disks, because disks are the only stable way to have collisional gas orbiting a central object over many orbits. Otherwise the gas streams will just run into each other and trade angular momentum until they've equilibrated to coplanar orbits.

Superclusters do not have a standard shape. This is essentially because the time it would take for them to undergo many dynamical timescales (the time for galaxies to complete an orbit around the center) and thus become regular in shape is longer than the age of the universe.

Galaxy clusters often do have a somewhat regular shape, at least in the sense that they have a large cD elliptical galaxy sitting at the middle and a spheroidal distribution of galaxies around it, with a gradually decreasing density of galaxies as you get farther away from the center. But even so, they are much less regular than the shapes of most galaxies, because they take much longer to smooth out the irregularities, and there are more galaxies falling into the cluster all the time.


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

[User] ELI5: Why are giant creatures generally found deep in the ocean?

[Assistant] Supporting a massive body on land means a constant fight against gravity. It requires huge powerful legs and muscles that take energy to build and maintain. In water this effect is largely mitigated by buoyancy. A massive body has less downsides in the ocean.


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

[User] ELI5: Why is it that most airliners have the small wings behind and the big wings in front, and very few have the big wings behind and small wings infront? In other words, why is the Canard arrangement so rare?

[Assistant]
With a "regular" tail, if the plane gets tilted so that the tail is really high or really low, the air pushing on the tail will push it back toward normal, level flight.

With a canard, if the plane tilts so that the canard is really high or low, the wind pushing on the canard will push it even farther up or down.

So a plane with a canard is harder to control.


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

[User] ELI5: How did they predict existence of subatomic particles, black holes, multiple universes using maths and equations?

[Assistant]
> subatomic particles

They didn't predict those with math. They were largely experimentally discovered. Thomson's cathode ray experiment found that there were negatively charged subatomic particles we now call electrons, for example.

> black holes

These were first thought of from Newtonian mechanics by Laplace (and others?), but it was really just an idea. After Einstein produced the general relativity theory, Schwarzschild predicted the limit at which a black hole could form.

> multiple universes

Those aren't mathematically predicted either, they're really outside the realm of science.


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

[User]
What were some of Nietzsches proposed solutions to nihilism?

Ive been reading his book Beyond Good & Evil, and while it is difficult to understand at times, I get the grasp of what he is trying to say. Because of this, Ive been taking my time and am only about a third through the book.

One question Ive been having about Nietzsche and his work in general, is what did he believe was the cure to nihilism? In other words, what will prevent the west from becoming more nihilistic? Does he ever talk about some proposed solutions to it towards the end of Beyond Good & Evil, or do I have to read another one of his books to find out?

[Assistant] He wasn't so much concerned with "the West." His focus seemed to be on those who had the will to make their own lives take the shape they wanted. His critique if western morality is that it's based on a skewed version of good/evil. His own view of goodness seems to be a sort of virtue ethics where the main virtue is to be fucking awesome.


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

[User] [Harry Potter] What is it that makes Avada Kedavra so bad when there are so many other spells which are equally lethal?

[Assistant]
Avada Kedavra is for killing. That's all it does. It's not even comparable to a gun, because a gun can be used for things like target shooting or hunting or self-defense. The Killing Curse, like the other Unforgivable Curses, only really works if you mean it, if you really and truly want someone to die.

(Now consider how casually Voldemort was able to use it.)


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

[User] ELI5: Would a centralized currency throughout the world work well, if at all?

[Assistant]
One problem with a world-wide currency is neatly demonstrated by Greece and the Euro.

One major way that a country can deal with hard times is to allow, or even force, their currency to be worth less. That makes the things you, as a country, make cheaper, and things you buy from other countries more expensive. So the country loses less money paying for exports, and makes more money selling its now cheaper exports. They can also create new money to pay for government spending, creating employment and pulling the country back onto its feet.

If there is only one currency, a country can't do this. Their citizens keep buying imports, and their exports remain too expensive, and they can't recover without cutting back hard on government spending, which makes the hard times worse.


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

[User]
[Skyrim]I'm a wealthy merchant and amateur magician, and I feel like setting up a small town. Where should I settle down, and what should I build?

When I say amateur, I mean to say that I'm passable at the arts of Enchanting and Alteration, I can place frost runes on things, and that's where my abilities end. As for how much money I have to throw around... Imagine a number. A high number. Now, before you decide upon that number, multiply it by two and try again. Regardless, I'm getting on in years, and I feel it's time to put my travelling merchant days behind me.

[Assistant]
Have you considered Rorikstead?

- Small, out of the way village.  Not much trouble comes up, plenty of land available to buy, all of it is fantastically fertile thanks to some careful land management by the people there.  Also, it's still near enough to the bigger cities that you can head into town for a weekend if you feel the need to see civilization again.

- Overall friendly disposition towards Wizards from the townsfolk.  The mayor's daughter is learning magic from another old sage who settled down there.  Pretty much everyone in town has at least an amateur interest in enchantment, judging by the large collection of soul gems.

- Something's keeping people alive and healthy there.  Maybe it's the good air.  Maybe it's clean country living.  Maybe it's a dubiously ethical and well hidden secret conspiracy of Daedra worshippers making obscene sacrifices in exchange for longevity and economic success.  Whatever the reason, the bloke named Rorik who founded the town in the first place is still alive and kicking, and you have nothing at all to worry about.


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

[User]
ELI5:If two engines have the same horsepower but one has 20% more torque what is the practical difference?

20% is just a random number. I just mean, if you have two engines of the same family and one is smaller but turbocharged and theyre both rated at the same horsepower but different amounts of torque.

Thank you.

Edit: I appreciate the responses but what I'm really asking here is what the difference between the two vehicles would be. Say we have two totally normal cars with 140 horsepower, one of the cars has 140 ftlb of torque and the other has 165. How do these two vehicles differ in performance?

[Assistant]
Torque = force (measured in newton meters[dimensionally equivalent to joules])

Horsepower = energy (measured in joules per second[watts])

**Horsepower tells you how much work your engine can do *over a time period*, torque tells you how much work your engine can do at *any given instant*.** That is why torque is much more important at a standstill, where wheels are static one instant but moving the next.

They are inherently related as Horsepower = Torque * Angular Speed. You can't increase torque or HP without increasing the other (while keeping RPMs constant).

Fun Fact: Trains use electric motors to get their wheels turning from a standstill because they can produce more torque than combustion engines.


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

[User] ELI5: How come we keep adding retail jobs despite the increase of online shopping?

[Assistant] Many stores cut staff way back during the great recession, well below the natural employment to run their stores, so they are building back up to that level (ie. Best Buy having a person working TV, and another working appliances rather than having one person covering multiple departments). One of the main ways for retailers to compete with online is by providing service/assistance buyers can't get online, so that takes more sales people. Also, it's just a big sector, that adding a large number of jobs may only be a tiny percentage of growth. There are something like 15 million people working in the retail sector, so adding 150,000 jobs is only 1% growth.


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

[User] ELI5: Why is there sand at the beach?

[Assistant]
It's caused by geological processes called mechanical weathering, transporting, and sorting. The previously formed rocks in the area are broken down by natural forces. I.e. water currents/waves, wind, ice expansion/melting, and tree roots breaking through rocks. These broken rock fragments or sediment deposits are then moved during a process called transportation. If it's a beach, then most likely the transport medium will be waves and ocean currents.

The sand is then sorted near the shore by how much force is involved in the transplant. Ex. Larger rocks deposited further from shore because the wave loses energy as it gets closer to shore and cannot move heavy objects. The energy in the waves, by the time it reaches shore, is just enough to move small grains. Usually beaches will have mostly the same sized grains make up the beach.

Notice that each beach has different sized sand grains. Some beaches have very fine sand. And some have very gritty large-grained sand. This is all due to the energy of the waves that reach the shore. The wave size is affected by the slope of the beach. Steep slopes lose energy faster, while gradual slopes lose energy slower. This is why Hawaii has huge waves. Some beaches have black sand. This is usually from volcanic activity near the beach that happens under water. The waves bring in whatever materials that it can push.

Hope this helps.


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

[User]
Is the average human being closer to the size of the entire observable universe or closer to 1 planck lenght?

On a scale that ranges from 1 plank lenght to 93 billion light years where would the average human being fall on that scale? would we fall towards the lower end or the upper end of the scale?

[Assistant]
The difference between a human and a Planck length is about the size of a human, and the difference between a human and the observable universe is about the size of the observable universe, so in absolute terms we're much closer to the size of the Planck length.

In relative terms, the size of a human is about 1 m, the size of the Planck length is about 10^(-35) meters, and the size of the observable universe is about 10^27 meters (about 92 billion light years), so in relative terms we're closer to the size of the observable universe by a factor of almost a billion.

Put another way, there are far more Planck lengths in a human than human lengths in the observable universe.


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

[User] Do all stars have Oort clouds?

[Assistant]
We don't know, since we've never even been able to directly observe our own. The existence of the Oort cloud is inferred/predicted from the presence of long-period comets. These comets have extremely elliptical orbits which bring them very close to the Sun for a brief period of time and then they return to the chilly outskirts of the Solar System, thousands or even tens of thousands of AU away from the Sun (1 AU is the average distance between the Earth and Sun). They spend up to millions of years in the outer Solar system during their orbits, depending on their ellipticity.

Comet-sized objects in the Oort Cloud are essentially impossible to observe with current technology. A 1-km wide comet at a distance of ~3000 AU (well inside the Oort Cloud) is about the same angular diameter as a 1-mm grain of sand on the Moon. They're just too tiny and faint to be anywhere approaching detection limits for even the best modern telescopes.

Of course, everything we have learned about the Sun indicates that it's a fairly unexceptional star, and that planets are quite common around other stars, so if the Sun has an Oort Cloud then we it would be a bit surprising if there weren't at least a substantial portion of similar stars which do too.


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

[User] Do people who survive Ebola develop resistance to reinfection?

[Assistant]
Yes! In an infection, the body takes some time to mount an adaptive immune response, because the correct T cells and B cells with the specificity for that pathogen need to encounter the virus, then proliferate and produce antibody to the virus.
After the virus is successfully cleared, those cells die and the antibody level goes down, but some B cells will remain as memory cells, which will produce antibody and begin the immune response much more quickly if you're infected a second time.

If infected a second time, the body mounts the aptly named **secondary immune response** which is much quicker than the response to the first infection (because the cells to make antibody are already around), and more effective (through a process called antibody maturation), where antibodies with increased specificity to the virus are basically selected for.

So in short, your body is actually very well equipped to deal with infections that it's seen before, in part due to having some memory cells around and due to "perfecting" the antibodies against that virus. This is why we get vaccines - in that case, you're injected with dead or attenuated antigen, the body recognizes and mounts a response, and you're much more protected in the event of infection with the live virus.


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

[User]
Is there a better solution to american colinalism than reservations?

Could you also point me to any resources discussing this topic if you know of any?

[Assistant] New Zealand is an example of a country that has taken a better (although not perfect) course with regard to the Maori people. Perhaps look into the Waitangi Tribunal, and the government's attempts to provide settlements to individual tribes based on historical research of wrongs done to them? Ultimately, however, no solution could restore their culture and the lands they held dear so no solution could be perfect.


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

[User] Earlier today, a winged ant landed on my windshield as I was driving. After it landed, it started pulling off it's wings (4 of them). Is this a normal behavior in ants, pulling their wings off?

[Assistant]
That was a queen ant who had been fertilized and was looking for a place to dig her nest. They pull the wings off as soon as they land, because they are not going to use them again. The flight muscles are used for energy while the queen is waiting for her first brood to hatch.

Winged ants are either queens or male ants. Queens don't keep their wings, and male ants die after mating is over, so there are no ants that fly merely as a form of locomotion.


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

[User]
[Fight Club][Spoiler] Why did other people start joining when they saw him fighting?

I mean if i saw someone fighting himself i would avoid him.

[Assistant]
Frustration. In their jobs they have no power and no real outlet for the rage and anger caused by whatever asshole was put in charge of them. Here they see a man who clearly enjoys getting hurt and they want to hurt someone. Once they've started it reawakens something primal, showing them that this is supposed to be the natural order to things.

You're mistaken on how you'd act. You wouldn't avoid him, you'd watch him. You'd consider it entertainment for a while, as did the men watching him, and then you'd either lose interest after a while or you'd initiate if someone else didn't do it for you. And that's when the cracks start to form. Before you know it, you're talking about things you're not supposed to and bringing your friends and co-workers into this activity started by some crazy guy kicking the shit out of himself.


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

[User]
ELI5: How does it hurt someone to be over-qualified for a job?

I'm planning to get my PhD, but I'm not entirely sure what I want to do for a career.  I'm worried that having a PhD would make me overqualified for other jobs.  I've often heard that this happens, but I do not understand why.  If I have a PhD in one subject, but pursue a career in an unrelated field, will my PhD hinder my chances of getting that job?

[Assistant]
The employer may feel that your high qualifications mean you won't be satisfied with the job, perhaps due to it being insufficiently stimulating. This might lead to you looking for other jobs and quickly quitting the old one.

The employer wants to avoid hiring an employee who will leave shortly, because then they would have to go through the application/interview procedure again which wastes time (edit: oh, and money, of course). So they don't hire someone that they think will want to leave very quickly.


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

[User] [Star Wars] What is the point of giving First Order troopers helmets that can filter smoke, but not toxins?

[Assistant]
I'd imagine it's because FO do not expect to encounter weaponized toxins. Only one glimpse in Earth history  shows how awful an idea chemical warfare is. But yeah, they naturally assume they'll encounter smoke, all the smoke from plasma or laser hitting its target and possibly igniting small forest fires etc. Not to mention all the burning they do otherwise.

Also, I'd second the notion that helmets with less filtration are cheaper and less bulky. It's economically sound, and the helmets they have already encumber them enough in combat. Plus, as the helmets are meant to look menacing (and dehumanize the troops, if you want to go meta), this added filtration probably could mess with that too.


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

[User] ELI5: Why has there been a shortage of NAND chips in the last two years?

[Assistant]
This subject is controversial. Companies are being sued over RAM pricing... theyre accused of either mis-representing the amount available or intentionally failing to produce as much as people want, to keep prices high.

NAND supply could be affected by similar factors, or it could be technical and market factors. Theres continuing/growing demand for cheap, power efficient storage but the newest 3D NAND tech has been tricky to produce. Meanwhile, phones are being sold with a larger amount of NAND storage. At the same time, desktop/laptop computers are moving away from spinning HDDs for storage, increasing NAND flash use for those devices. This holds true even when storage sizes arent increasing.


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

[User]
ELI5 why my computer speakers go spastic every time i get a call on my phone

Whenever i receive a call or dial a number on my mobile my computer speakers make a really loud and annoying noise

Why does this happen?

[Assistant]
Your mobile phone communicates with the phone network using electromagnetic radio waves.

One feature of electromagnetic waves is that when they pass through a wire, they create an electric current in the wire.

This is what's happening. The phone is generating electromagnetic waves so it can communicate with the phone network. These waves are creating electric currents in the wires that go to your speakers - only small currents, but they are there. Your speakers amplify these currents and convert them into sounds.


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

[User]
How random is our universe?

What I mean by this question is say:
I turn back time a thousand years. Would everything happen exactly the same way?
Take it to the extreme, the Big Bang: Would our universe still end up looking like it is now?

[Assistant]
It's not random at all; there are well-defined laws that govern how the state of the universe evolves from instant to instant. However, some of those well-defined laws are *probabilistic* rather than *deterministic.* That means it would be impossible to predict with certainty, even if you had perfect knowledge, how the universe would evolve from one instant to the next.

So the best anyone can really say is that if you did the last billion years (or whatever) over again, it's *possible* things would evolve in exactly the same way, but it's not *guaranteed,* and in fact one could reasonably say that it's vastly, vastly improbable.


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

[User]
[X-Men Days of Future Past] What stops Sentinels from targeting humanity?

If the Sentinels' goal is to eradicate mutant life, won't that mean once they have destroy all the present mutant, they will go after the remainder of humanity?

[Assistant]
Yep. And in the comics, thats happened several times.

In one of their early appearances, Cyclops stopped them by pointing out that all life on Earth comes from the Sun, so an army of Sentinels flew off to fight the Sun.

Spoiler alert: They lost.


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

[User]
[Contact] She travels for a few seconds relative to earth time but several hours to her own time? Reverse relativity?

I thought with relativity when traveling through space, people observing you would see you traveling at a slower speed etc. Meaning you go away then come back for 1 hour your time but several years relative to earth.

This seems to be reversed in Contact? Why?

[Assistant] I would assume that whatever Sufficiently Advanced Aliens interacted with her have the ability either to lengthen her subjective perception of time or actually send her back in time as well as through space to just after they first teleported her.


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

[User] [40k] What exactly is a C-tan?

[Assistant]
They're basically energy beings that used to go around sucking the energy out of stars to survive. Then they discovered life, in the form of the Necrontyr, after the Necrontyr discovered one feeding on their star. They found that they far more enjoyed feeding on life force. The Necrontyr gave them physical bodies, in the form of necrodermis (basically living, regenerating metal). The C'Tan then got the Necrontyr to transmute themselves into necrodermis, granting them immortality and creating the Necrons.

Nowadays, the C'Tan's necrodermis bodies are mostly in fragments, held by various tomb worlds to stop them from reconstituting fully. The Necrons rebelled against the C'Tan and destroyed most of them, though one (the Void Dragon) may be whole and slumbering under Mars.


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

[User]
Why is there no such thing as "knockout gas"? Or really any comic book standard non-lethal weapons.

I understand things like chloroform or any anesthetic must be accurately dosed to avoid brain damage/death, but is there anything out there dart, gas, topical, etc that could knock someone out?

[Assistant]
A dart can, and has been used for this purpose, however the effects take at least 30 seconds to 1 minute, so it is not immediate. Gas is much to unpredictable and without a trained anesthesiologist on hand to fix any airway problems, could be fatal.

The Russians tried gas several years ago in a theater hostage situation and killed several dozen hostages.


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

[User] What statistical methods are used in order to come to a conclusion on the expected expiration date of a food/drink product?

[Assistant]
Here's something from the New Zealand government about calculating shelf life.  Although it doesn't go into the exact statistical methods, it's still good info:

>PREDICTIVE MODELLING

>Predictive models are mathematical equations which use information from a database to predict bacterial growth under defined conditions. Predictive models can be used to calculate the shelf life of a food. Information on the changes that occur in the product when it deteriorates, the properties of the product and packaging is required for the calculations. Most predictive models are specific to particular types of organisms.

>Some examples of predictive modelling systems are the United States Department of Agriculture (USDA) Pathogen Modelling Program (available to download from the internet), Growth Predictor and FORECAST (a paid service by Campden and Chorleywood Food Research Association (CCFRA)).

>Models are useful as a first step in the evaluation of a products shelf life. However, information from modelling programmes needs to be verified by challenge testing or a shelf life trial.


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

[User] How does digestion change in space when your stomach acid is floating around in your stomach?

[Assistant] Contrary to 90% of the depiction of your stomach, it's not an empty cavern.  It's more like a deflated, squishy, football, sometimes with a little air bubble left in it.  Your breathing and movement help move things along, gravity has nothing to do with it.. So eating in space is fine because you're still breathing and moving.


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

[User]
[WH40k] Why are space marines so important to the Imperial war effort, when there are millions of guardsmen per one marine?

In-game they're only about as strong as 3 guardsmen, and while they're portrayed as being much stronger in the books, shouldn't that mean they can take on forces of orks, chaos daemons, or tyranids hundreds of thousands of times their size? And don't space marines use much of the same weaponry as guardsmen, such as flamers, meltaguns, and plasma guns?

Are space marines that important of a fighting force, or are they just living propaganda?

[Assistant]
A little bit propaganda and a lot of special forces.

A million guardsmen can take and hold a planet, but it is loud, expensive, and slow.

Slow is the worst part there, especially when dealing with Chaos. Give the agents of the Ruinous Powers enough time and they'll leave out patsies and move their operations elsewhere. By the time the guardsmen clear the first temple, cultists will have moved to the second temple, and by the time the guard has found the second temple the cultists will have gone to the third and begun consecrating the first one again.

With the Astartes you have no hesitation- the troops that arrive have been training in urban combat since the guardsmen's grandparents were in diapers. Their armor and speed and weapons mean rapid assaults, quick kills, and a surer result, no having to pause and rethink tactics or issue specialized equipment (void suits, gas masks, etc.)

Much like Marines found elsewhere, the Astartes are a precision instrument, to be applied carefully. They establish the landing zone for the Guard to take, they clear out the worst resistance before the Guard can notice it, they bolster the Guard by taking on the opponents that guardsmen hesitate to engage.


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

[User] Based on the Voyager probe trajectories, is it possible to calculate where they will end up thousands or millions of years in the future?

[Assistant]
Their trajectories out a few tens of thousand years are known, since they will remain in the Sun's gravitational sphere of influence for most of that time.

Within a few hundred thousand years, the Sun will be an inconspicuous speck of light in the Voyagers' skies.   Their future trajectory will be influenced by the masses they encounter: stars, gas clouds, etc.

Since we don't knowing the mass, density, location, and velocity of all of these objects, it will not be possible to calculate anything better than a rough approximation of Voyagers' trajectories beyond this.

And sometime in the next decade or so, the Voyager RTGs will finally weaken to the point that communication with Earth will cease, taking with it our only means of tracking them.


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

[User]
Difference between scholarship and fellowship?

I am a new grad student applying to some scholarships, and I'm not too clear on the difference between what's a "scholarship" and what's a "fellowship". Which category would guaranteed research funding by my school count as, for example?

[Assistant]
Guaranteed funding is most likely a fellowship.  There's a lot of overlap in meaning, but in broad strokes, a scholarship is for students/academic pursuits, while a fellowship is for pursuing research (as a students, etc.)

Do be aware that there may be tax collection differences on them if in the US.  Again, broadly speaking, scholarships aren't always taxable, while fellowships are and require estimated tax payments.


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

[User]
Why can't we actually observe dark matter?

I mean can't we just observe any kind of ordinary matter with the right instruments? So why aren't those working for the postulated thing called "dark matter"?

[Assistant]
We can observe dark matter.  We observe dark matter through its gravitational influence on other objects, such as stars and galaxies and light.

Dark matter, however, does not emit or reflect light, so we cannot see it in the literal sense of seeing things.

By the way, dark matter is not the only thing we observe via its gravitational influence.  There are planets that we have detected purely by means of the gravitational force they exert on their host star as they complete their orbits.


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

[User]
cmv: The Uruk-Hai Berserker was the most courageous character in Lord of the Rings.

A warrior who knowingly sacrifices his life to kill the enemy may objectively be considered brave or courageous, whether the cause was morally just or not. The Uruk-Hai Berserker sacrificed his life for his cause, and watching that scene by itself, without any context, he appears to be acting heroically.

He was a trained warrior who was given advanced orders of a planned attack, and he willingly followed them, putting himself in a lethal situation. Knowing that the bomb he was carrying would take his life, despite being arrow-shot multiple times, he never wavered and never hesitated until his mission was completed successfully.

No other character in the trilogy exhibited this level of selfless courage.

Many characters exhibited bravery, and Gandalf and Borimir both went down in battle, but the key difference is that they all fought knowing that they had a chance of surviving. The Uruk-Hai Berserker accepted a mission where his death was certain.

[Assistant]
The berserker was raised from birth(?) to die in battle. If not in a suicide mission, then in a more conventional frontline battle. That's all it had to look forward to - even the Mordor orcs had a level of independence that led to the handful of them talking about ditching Sauron and going into the world to do orc things on their own. The Uruks, on the other hand, were built for war, physically and mentally, in the name of a greater power. If something's self-preservation instinct is that degraded by nature and by conditioning, can anything it ever does really be said to be brave?

Compare and contrast any of the hobbits who were on the quest. They're farmers. Frodo was looking forward to another fifty-eighty years of hanging out in the shire, eating good food, smoking pipeweed, and maybe pranking the Sackville-Bagginses with Bilbo's funny magic ring. He gave it up for a mission he had no reason to believe he would survive and then persevered even once that became certain - he couldn't have known the Eagles were coming.


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

[User]
[Star Trek] Single Species Crews?

The crew of DS9 once engaged in a "baseball" game with the crew of another Starfleet ship. The opposing crew was entirely Vulcan, or maybe it was just the senior staff.

Regardless, how would a Captain be allowed to do this? I can understand a Captain being given some leeway in selecting his crew, especially senior staff, but isn't that discriminatory? It seems very much against the spirit of equality that much of the Federation stands for. Aside from that, it seems a  terribly inefficient and illogical way to deploy resources. Even if Vulcans are "superior" to other races, wouldn't it be better to spread them around the fleet?

[Assistant] While humans and vulcans are capable of surviving in the same environment, their optimal temperatures are uncomfortable for each other.  Vulcans like things a fair bit hotter than humans do.  Because of that,  ships tend to be primarily one species, with maybe a few officers here and there that wanted a particular assignment enough to deal with being too hot / too cold.  **Entirely** single race ships are rare, but ships that are around 90% a certain species are the norm, not out of some manner of racism, but just basic comfort.


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

[User]
Can black holes move?

This may be a silly question, but bare with me.

Could in theory a black hole have momentum like say a comet.  Traveling different galaxies and sucking up things that get close to it?

If so, what would happen if it passed through or collided with something like our sun?

[Assistant]
Yes, black holes can and do move.  Keep in mind that all movement is relative -- if you are stationary compared to a black hole then it is not moving, while if you are passing by it at some speed then the black hole is moving.  There is no such thing as absolute movement.  Whether a black hole has momentum or not is entirely based on your choice of reference frame in which to observe the black hole.

But, while black holes move around inside galaxies, they don't generally have enough relative momentum to travel between galaxies.  They, like all other celestial bodies, tend to occupy a single galaxy.

If a black hole collided with our Sun, depending on the size and mass of the black hole it would likely consume at least part of the star and disrupt the rest.  Our orbit and solar system would be thrown into chaos and we would all die.  Fortunately, this is statistically very, very unlikely to happen which is why it hasn't happened already.  Space is *incredibly* vast, and black holes and other stars are quite dense and tiny compared to the distances between them.  Even when the Milky Way eventually collides with Andromeda and the two galaxies merge, our solar system is probably going to be perfectly fine and all the stars will just fly past and between each other, mostly unaffected.


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

[User] When you drop a pebble in water, you hear a sound wave, and you see ripples along the surface. Is the distance between the ripples on the surface the same as the wavelength of the sound wave?

[Assistant]
What you hear is the soundwave as it travels through air. So it will have a different wavelength vs. traveling through water.

The waves you see are not indicative of the sound's wavelength. It is a physical reaction to the pebble breaking the water's surface and displacing water in a cycle.


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

[User]
ELI5: Why do bugs like spiders just stand in one spot for long periods of times.

Like the spider on my wall who hasn't moved in 30 minutes.

[Assistant]
It's probably just trying to conserve energy. It doesn't get anything out of moving around if there's no food. Out in nature, it'd be easier to spot a bug that is constantly moving around, too, so it would be advantageous to stay still when not actively trying to find food.

Additionally, if it's cold, bugs are less likely to be moving.


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

[User]
Will being near a large particle accelerator such as the LHC cause a magnetic compass to drift from true north?

If I am walking near the LHC on the surface how close would I have to be for my magnetic compass to drift an appreciable amount due to the strong magnetic field?

[Assistant]
Accelerator facilities often use strong magnets to steer and focus their particle beams. These magnets will in general have fringe fields when they're turned on and ramped up to a significant current. If you come within the range of the fringe field, you will see magnetic effects such as deflection of compasses, distortion of CRT screens or other electronics, erasure of credit card strips, etc. You shouldn't be near them if you have a pacemaker.

The magnets used in these facilities are mostly dipoles and quadrupoles, so their fields drop off as 1/(distance)^(3) and 1/(distance)^(4) respectively. Often they'll have some magnetic shielding around them or additional coils to minimize fringe fields, so the ranges will probably be even shorter in practice.

In other words you need to be pretty close to the magnet for these things to happen.


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

[User]
[Diablo] How does humanity still exist?

I was lucky enough to survive the assault on Bastion's Keep. I saw it with my own eyes... The endless horde... I'm only here because I was lucky the Nephalem appeared that second, literally any half second after I would not be here only missing an arm.

My question is, even with the Nephalem's efforts, how does humanity still exist? We are far outnumbered by these demon spawn. They kill indiscriminately. I myself only come from a family of 4, my parents and a younger sister. We cannot possibly procreate fast enough to replace our losses...

Can we? At least not against the sheer and innumerable wave of evil?

[Assistant]
It's not all-demon all-the-time. There was a good amount of time between the second and third demonic invasions. They also tended to be geographically limited.

And even without the Nephalem, humans can be pretty badass. The first two batches of heroes weren't Nephalem, just fairly elite, and ~~their companions~~ the followers in Diablo 2 and 3 were ordinary humans. Even the latter group did a fair bit of damage, which shows what people can do with the right training and equipment.


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

[User]
[Endgame] When Captain America told the Hydra Agents in the elevator scene Hail Hydra wouldnt that alter the events of Winter Soldier?

Im not sure how the timeline works here. It was established that the TVA allowed this course of events to occur, but Cap saying Hail Hydra surely would make an alternate timeline where Hydra thinks hes always been a Hydra agent right? But that wouldnt make sense since the TVA maintained only 1 timeline.

[Assistant]
The TVA *didn't* maintain only one timeline. According to them, they only pruned timelines that deviated *too far*, creating variants. Typically, they only pruned *individuals* to keep things on a reasonable course, *not* entire timelines.

Of course, that was just a front put up by He Who Remains, and the actuality of it is that they only pruned timelines that would give rise to new versions of Kang.

There were literally an infinite number of timelines that the TVA didn't care about. They didn't even care about there being a Crocodile version of Loki *UNTIL IT ATE THE WRONG CAT*.


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

[User]
ELI5 what happens to all the soap?

What happens to all the soap, shampoo and detergent we flush away from our showers, washing machines etc? How is this separated in order for the water to become useable/drinkable?

[Assistant] Mostly all soap is biodegradable, so it will decompose naturally. Most waste-water will go to a wastewater treatment plant. These plants use process such as sedimentation, coagulation, aeration, and eventually filtration to create to by-products, clean environmentally safe water and sludge.


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

[User]
[Star Wars] Why didn't Qui-Gon Jinn warn the Jedi Council about Palpatine?

Force ghosts can travel wherever they want to in the galaxy, and Qui-Gon in particular would have been motivated to find out who the Sith Master was. He must have known about Palpatine's deception, so why not tell the Council?

[Assistant]
> Force ghosts can travel wherever they want to in the galaxy

Can they?

I have only heard of Force ghosts manifesting next to someone who is Jedi-trained, and its usually someone the ghost has a connection with.


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

[User]
ELI5:Why everyone is so scared of a terrorist attack at the olympics?

Edit: sorry for the bad grammar:
Why is everyone so afraid of a terrorist attack at the olympics?

[Assistant]
* There have been two terrorist attacks in Russia recently

* The group that perpetrated those attacks has said they were planning an attack at the Olympics

* Sochi is near places where a lot of terrorist activity goes down

* There's a lot of people in one place expecting joy and celebration, which is a prime target for a terrorist attack.

* The security in Russia right now is pretty weak, because Russia as a country is kind of a shithole right now.

* There was a terrorist attack during the 1996 Olympics, and the security there was far tighter than security at the Sochi olympics.

Generally it's just a big, almost-perfect storm for a terrorist attack to go down. It may not happen, and it probably won't, but it's definitely a possibility.


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

[User] ELI5: What actually happens when a program stops responding? Why does it sometime crash and other times continue working?

[Assistant]
Let's start off with your operating system.  That's going to be Windows, etc.  That's your overseer within the computer, and it communicates and interfaces between you and the other applications inside the computer.

Normally, the operating system (OS) is freely communicating between you and the programs, but sometimes, this communication breaks down, which is to say the program isn't responding to the OS's requests.  This can be because of a bug in the program, or because the program is busy doing its thing and doesn't bother to respond to the OS.

Sometimes, the program just needs a little time to catch up, and when it gets finished with its current task, it reestablishes communication with the OS and the program continues working.  Sometimes, however, the program gets caught up in its own thing and runs around in circles over and over again.  The program isn't going to respond.  Occasionally, but not always, the program may trigger a break command, which says that if that line of code is reached, terminate, because the program has found its way in Bad Place (TM) and won't be getting out.  That's when the program crashes; the program has triggered its own self-destruct sequence.

But sometimes, the program just sits there and waits forever.  You might tell the OS to try to close the program.  If the program still doesn't respond, you can force the program to terminate, which is to basically have the OS take a gun to the program and execute it (in the sense of taking it out back and disposing of it).


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

[User] What happens to the energy from UVA/UVB rays when I'm wearing sun screen? Is it reflected or absorbed, and if it's absorbed does this result in additional heat energy?

[Assistant] It's mostly absorbed. But without the sunscreen, it would be absorbed anyway, by your skin, so it doesn't really result in extra heating. Just prevents the UV photons from reaching living skin cells and knocking electrons off things that you don't want electrons knocked off of.


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

[User] Eli5: Why can't cell phone manufacturers use carbon fibre to build phone body instead of plastic, ceramic, glass, etc. ?

[Assistant]
They totally could. Why would they? Carbon fiber scratches fairly easily and can shatter. It's biggest advantage is being lightweight, which isn't super necessary for a tiny phone anyway.

Plastic's way cheaper and plenty durable. Glass is scratch resistant. Aluminum is strong.


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

[User]
Can we transfer information through UV, Xray, and Gamma waves?

In class, we are currently learning about the physics of energy - Our definition for a wave is 'an oscillation/vibration that transfers energy/information through the medium in which it travels.'

so is it possible to transfer information through UV, Xray, and Gamma waves?

[Assistant]
You could, but those frequencies are not as good as radio for data transmission as they are readily absorbed by solids or air. Also, they all give you cancer.

They're good for imaging though. Near-UV photography is a thing,  in fact a very interesting thing. X-rays are obvious. Also, there's UV astronomy, X-ray astronomy, gamma astronomy.


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

[User]
[40k] What would be needed to stop the Tyranids?

Like what hundreds of Primarchs and The Emperor of Mankind himself? Every faction uniting?

[Assistant] One Inquisitor with an especially mighty hateboner for them wanted to blow up all the planets in their path and starve them, but was stopped halfway through because it was too damaging to the Imperium(plus, an individual Inquisitor can blow up a planet, but the higher-ups got spooked at the idea of one ordering several at a time).


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

[User] ELI5: Why does google have a better spell checker than dedicated text editing programs?

[Assistant]
Google's spellchecker watches what people do and learns from them.

The first time somebody made that particular mistake Google probably wouldn't have offered a very useful correction. However once enough people manually corrected their spelling it would've become the top suggestion.

Bing (another Microsoft product) automatically corrects comphreensive to comprehensive if you try and search it.

Maintaining this type of spell checker is quite complicated, you need a very large database of errors and corrections.

Microsoft's desktop software such as Office and Internet Explorer have a purely-offline spell checker. Compared to the online versions it's much simpler, the software has a dictionary of every word is knows, and some information on the most common errors (for example infornation automatically corrects to information). An algorithm decides which corrections to offer for a misspelled word, this algorithm is designed to work very fast on personal computer hardware; whereas Google and Bing's approach only really works thanks to their large computational resources.

Of course the closer you are to the actual word the better the offline algorithm will work. 'comphrensive' not only has the h in the wrong place but is also missing an e, Office offers comprehensive as the top correction for both 'comphreensive' and 'comprehnsive'.


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

[User]
CMV: Joe Biden Should Note Run For President

I keep seeing that places are including Joe Biden in presidential polls, even though he hasnt even announced his candidacy yet. He seems to be doing pretty well in these polls, but I dont think he should run for president.

Even though he is polling well, he is not polling overwhelmingly well. A lot of the other numbers are split between more progressive candidates. I believe that, if Joe Biden runs, it is very likely that he will secure the democratic nomination, but it is very unlikely that hell secure the presidency. Why? He is basically Hillary Clinton 2.0 with less background controversy, he wont excite the progressive wing of the party, he wont appeal to independents, and he wont appeal to Republicans who dont care for Trump.

I think if a more progressive or outsider candidate secures the democratic nomination, they will have a better chance against Trump, and they are more likely to do so if Biden does not enter the race. Change my view.

[Assistant] If hes Hillary with less background controversy, then thats a pretty solid place to be. That background controversy was the singular most problematic part of her candidacy, and she still came damn close. Id argue that Biden is a good bit better than that, too, but even that is pretty solid.


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

[User]
AskScience AMA Series: I'm Paul Sutter, astrophysicist, amateur cheese enthusiast, and science advisor for the upcoming film UFO. Ask Me Anything!

Hey reddit!

I'm Paul Sutter, an astrophysicist and science advisor for the film UFO, starring Gillian Anderson, David Strathairn, Alex Sharp, and Ella Purnell. I am not nearly as beautiful as any of those people, which is why I'm here typing to you about science.

The film is about a college kid who is convinced he's recorded an alien signal. I helped writer/director Ryan Eslinger, plus the cast and crew, make sure the science made sense. And considering such topics as the Drake Equation, the fine-structure constant, 21cm radiation, and linear algebra are all (uncredited) costars in the movie, it was a real blast.

I also briefly appear in one scene. I had lines but they didn't make the final cut, which I'm not bitter about at all.

Besides my research at The Ohio State University, I'm also the chief scientist at COSI Science Center here in dazzlingly midwestern Columbus, Ohio. I host the "Ask a Spaceman!" podcast and YouTube series, and I'm the author of the forthcoming Your Place in the Universe (which is like Cosmos but sarcastic and not a TV show). I do a bunch of other livestreams, science+art productions, and TV appearances, too. I also consult for movies, I guess.

I'll be on from 2-4pm ET (19-21 UT), so AMA about the science of UFO, the science of the universe, and/or relationship advice. As I tell my students: my door is always open, except when it's closed.

[Assistant] What has prevented you from taking that step up from amateur cheese enthusiast to professional cheese enthusiast?  Is it giving up the glitz and glamor of the astrophysics world or do you secretly think you might not have what it takes to compete in the high stakes world of cheese enthusiasm?


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

[User]
ELI5: Why is polydactyly so uncommon when it is a genetically dominant trait?

Shouldn't dominant traits become more popular over time?

[Assistant]
Dominant traits don't in general become more common over time.

This is somewhat counter-intuitive. You generally have two copies of each gene, one from each of your parents. The gene that expresses itself in you is called dominant. However the other gene is still there and you will have a 50% chance of giving it to your child. Dominance or recessiveness doesn't, in itself, affect the prevalence of that gene in the population.

The usefulness of a genes expression is what causes its prevalence to change over time.


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

[User] [cars]. did the planes in 9/11 get hijacked or were they in on it?

[Assistant]
Cars 9/11 means Cars war in the Middle East.  Which means Cars cold-war, and the invention of Cars cold-war bombers over Afghanistan, meaning sentient vehicles created only to kill ground-targets.  ~~For kids!~~

So, the "hijacked" Planes entities were likely captured in Afghanistan, brainwashed by Car-Quaida, and carried out their destruction of the world's tallest parking garage.  Possibly even Planes that helped to taxi military equipment when the Afghans fought the Soviets.

One of the Planes' mental conditioning broke over a field in Pennsylvania and he committed suicide rather than complete his mission.

So, mental hijacking.


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

[User]
How does the rotation of the earth affect air travel?

When you take a flight, one can imagine how you can either fly along with the rotation of the earth or against it.

Yet a quick google search shows, a flight from New York to Tokyo is about the same time as a flight from Tokyo to New York.

Why is this, and how exactly does the rotation of the earth affect our air travel?

[Assistant]
it has an effect due to the winds, and those winds blow the way they do largely due to the rotation of the earth (and how the sun heats up a portion of the earth as it (the earth) rotates under it).

It is quite a significant effect at mid latitudes.  For instance,  a flight going east is probably 25% or so quicker (and less expensive) than the same flight going west.