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

[User]
Is running out of Helium a real concern?

I have heard about an upcoming shortage of helium and that the element is not a renewable resource.  Are we really going to run out and what are the implications of this?

[Assistant]
It's not a renewable resource since we have to pump it out of the ground.  There are very few places in the world that are capable of that.

Like all things we're 'running out of', we're never actually going to run out.  The price is going to go way up, but we're not going to run out.  Helium balloons at birthdays are going to be a thing of the past, most likely, but those were superfluous anyways.  What we really need He for is chilling the superconducting electromagnets in NMR and MRI machines and particle accelerators, and also to make clean atmospheres for growing silicon wafers and the like.  The former can handle a little more expense and development of high-temp superconductors will help a whole lot.  The latter may be able to absorb the expense, as well, and could use neon or argon in some applications.

EDIT: Low-temperature physics research requires He for lots of things.  See scasagrande's post below.

So not the end of the world, things will get more expensive, and your kids won't get to have balloons at their birthday party.


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

[User]
[DC Comics] What stops an enemy from killing the flash when he is unaware?

I have read that by default the flash is in normal mode where he perceives time like a normal human being, what stops an enemy from killing him instantly without noticing?

[Assistant]
His reflexes are always cranked up to the 11th power all the time.

So although it's really inconsistent, if you tried any sort of physical attack against him, his body would react without him even noticing.

Example: When under constant fire from a swat team, The Flash does not need to consciously decide what part of his body he should vibrate to allow the bullets to go through without harming him. When he feels the heat of the bullets approaching him, his body responds automatically without him even realising that he was just shot in the back of the head.


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

[User]
ELI5: Why does sugar sometimes cause pain in sensitive teeth, but salt does not?

Ive had sensitive teeth ever since i was a child, and while writhing in pain after eating a chocolate bar about 20 minutes ago, i began to wonder why salty foods never seem to cause me this much agonizing physical pain.

[Assistant] The mechanism of sensitive teeth while not fully understood, is mostly attributed to fluid movement in teeth with worn down enamel (Hydrodynamic theory) . Sugar facilitates the movement, while salt does not.


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

[User]
Native Americans died from European diseases. Why was there not the equivalent introduction of new diseases to the European population?

Many Native Americans died from diseases introduced to them by the immigrating Europeans. Where there diseases new to the Europeans that were problematic? It seems strange that one population would have evolved such deadly diseases, but the other to have such benign ones. Is this the case?

[Assistant] There is a theory that Syphilis was brought back from the Americas by Spanish sailors. It is known that Syphilis was present in Pre-Columbian America but there is no recorded instance of an outbreak in Europe until 1495 when it broke out in the camp of French soldiers besieging Naples. From there it spread across Europe and would continue to be a major health issue in Europe until relatively recently.


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

[User]
What's the highest speed of the Internet? The speed of light?

I'm not talking about connections speeds exactly, but how fast can a packet of information travel from point A to point B.

[Assistant]
Yes, the fastest possible speed for any communication, including the internet, is the speed of light. Most internet links are slower than that. Even light will travel at somewhat less than *c* (the speed of light in a vacuum) if it's moving through a medium, like optical fiber.

This means there's a minimum latency, that is, the time required to go from point A to point B, depending on distance between the two points (about 1 millisecond each way for each 300 km). If you're connected to a server 3000 km away it's going to take at least 20 milliseconds to get a response.


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

[User]
Have we put life on Mars?

Unless the rovers that we sent to Mars were 100% Sterilized before they were launched, wouldn't they have carried with them lots of microorganisms, even ones that could eventually evolve into more advanced life forms?

[Assistant]
That is a serious possibility, and scientists have done everything they can to avoid it, but undoubtedly some bacteria have survived the trip. Mars is still extremely hostile to bacteria, so ones that survive the trip are just as likely to die on the surface, and even if they survive in hibernation on the surface, there's no water and little chance of them reviving.

So basically, there is a small amount that survives but it isn't very likely to thrive on Mars.


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

[User]
Dealing with a student's religious objections to course materials- English instructors' advice especially appreciated

I could use some advice from other instructors. A student approached me after our English class today and said that he can't read our assigned text, as it offends his religious beliefs and makes him uncomfortable. I appreciate his discomfort, as the book is critical of Christianity, in addition to depicting sex acts, though I wouldn't describe it as inflammatory or aggressively anti-Christian. Still, I can see his point.

I could exempt him from the reading and all related assignments and assign him an alternative text. But he would not benefit from any class discussions about his chosen text, and our class discussions about the offending book would be sure to upset him.

And moreover, what is his college career going to look like if he sets this precedent for himself? English class exposes students to a range of provocative materials, and I had always considered this to be a net positive. Surely students who wish to shield themselves from such views often go to Bible college. In the wide world of secular academia, religious discomfort is inevitable.

Still, I place myself in his shoes and imagine reading something I find deeply troubling and morally outrageous. And I feel pretty good that he felt he could say something to me about it. I'd appreciate your thoughts on this.

[Assistant]
The ability to meaningfully engage with work that doesn't agree with one's core beliefs (and is perhaps critical of those beliefs) is one of the greatest lessons one can learn and is something higher education should strive to encourage in students.

Tell this to the student and strongly suggest that he do the work.

Alternately, shield him from views that do not accord with his own and help us down the path towards a planet full of blinkered ideological subgroups that are absolutely incapable of meaningfully interacting with one another.


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

[User]
Our brains outside of our body

Im new to this subreddit but i was curious about the possibility of our brain still working outside of our body. If say, we were able to keep our brain alive after death (but just by itself, meaning not put into a robot body of some sort) would our brain still act as our regular self if that makes sense? Although we wouldnt have our body, our sight, hearing, or body sensations, would our brain consciously know who it is still and be able to think like regular? or does the brain needed other key elements in the body to have a full consciousness? if so, what is our self made up of if its not just the brain itself? and could the brain be aware of itself and its situation? overall im just curious if the brain, by itself, can still be like your regular self, just without the body. this is hard to word but i tried my best!! if u have any insight id love to hear! :)

[Assistant]
This is a common topic in philosophy of mind. A great introduction to this theme would be to read Where am I? by Daniel C. Dennett.

It is a very short story about the relation between body and mind, the self and the perception of reality.


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

[User]
ELI5: How do turbocharged 4 cylinders get so much better gas mileage if they have to inject more fuel than an NA motor to keep the correct AFR?

It seems like most cars get better mileage because so many have a turbo 4 cylinder, but what difference does it make in fuel consumption if you have to use more fuel to match the higher amount of air in the combustion chamber?

[Assistant]
A modern 4 cylinder turbo is probably around 2 liters. The equivalent would be something like a NA 3.6L V6 or even a NA 5L V8.

The car is only on high boost during acceleration. So most of the time when cruising, it doesn't require a lot more fuel. The larger engines have to burn fuel for all that additional capacity all the time (albeit perhaps at lower revs) unless the engine has selective cylinder deactivation.

The other savings is of course, weight.


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

[User]
Do people who are sunburned easily have more or less a chance to get skin cancer?

Damaged cells are told to die so as not to turn into cancer cells.  So, would this not mean that if your skin cells die relatively easy, you would have less of a chance for cancer?

[Assistant] No. In fact youre more likely to develop skin cancer. This is exactly why some people have more melanin in their skin, to prevent sunburn and associated cancers. The more sunburns you have the more likely you are to get skin cancer especially if its a childhood sun burn.


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

[User]
[DeadSpace]What kind of considerations have to be made when cracking a planet?

Surely removing/harvesting a planet can have knock-on effects on a solar system when we begin harvesting a planet. What kind of decisions are made, are there things that could go wrong? What are the risks beside the marker incident?

[Assistant]
I imagine it is similar to the considerations one makes before drilling for oil. So, if doing it the right way, impact on surroundings, potential dangers, etc.

If you do it the american way...

"Is there oil there?" "Idk...maybe." "We drill at dawn."


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

[User] Could a planet ever be ellipsoid shaped, with the poles at the 'pointy' ends? If Earth was ellipsoid (long longitudinally, short latitudinally) what would be the most noticable differences climate-wise etc.?

[Assistant] A slowly rotating planet (or star) will always be an oblate (flat) ellipsoid.  It will not look like a football.  If it is rotating rapidly enough, it will take on a dumbbell shape, but the lobes will be in the equator, not at the poles.


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

[User]
New hero here trying to get a grip on my powers, and I'm in a bit of a predicament.

Hi all!

I recently got my mutant powers, and it turns out I'm a shapeshifter!  Pretty much like Beast Boy, i guess, so nothing unique.

Unfortunately, I've been put into a pit fight with all of the worlds greatest heroes and villains, and the only way out is to beat them.  All of them.

What am I going to do?!  I can change into any living creature that I can imagine from the size of a flea to the size of a blue whale, but I think I might be doomed!

I'm up against the likes of Super Man, Hulk, Batman, Deathstroke, Professor x.....the list goes on!

Help!

[Assistant]
Immediately find and grok Starro if you're not already familiar with it.

Shapeshift into Starro.

Clone self and latch yourself onto as many other combatants as possible, killing who you can all the while.  Make sure this includes Superman (latching onto not killing just yet).

Superman has a vast knowledge of many alien animals because he has a zoo of them in his Fortress of Solitude.  Ostensibly, he is also familiar with Kryptonian animals as he studies Krypton as much as he can.  Absorb this knowledge while one of your Starro clones are latched onto him.

If someone interrupts the Starro plan, we move to Plan B.  Shapeshift into the fiercest Kryptonian animal you managed to grok.  You are now hopefully an apex predator from a planet with a red sun now powered by a yellow sun with a human mind who hopefully just absorbed a bunch more strategic info during the whole Starro thing.

Dominate.


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

[User] [Star Wars] How did Kylo Ren know the lightsaber used to be Anakin's?.

[Assistant]
The guy had Anakin's helmet sitting in his room, and had a remarkable obsession with him. By the time Kylo Ren was around, it would be open knowledge that Darth Vader was Anakin Skywalker, so his obsession with Vader would extend back to Anakin as well.

Anakin Skywalker was a war hero, and commonly the one pushed into talking to the public. It's very likely that holorecordings would exist of him fighting, and that you could make out his lightsaber in those. The average person wouldn't really pay attention to that... but Kylo is obsessed. He'd learn everything he could about Vader *and* Anakin; comparing their movements and forms, their lightsaber designs, etc. If anything, he had a lot more in common with Anakin at that point than he did with Vader.

Combined with any Force impressions he could feel (and Rey's flashback sequence indicates that it has some *heavy* impressions), it would have been weirder if he *didn't* recognize it.


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

[User]
ELI5: What are the differences between Formula 1 cars and Indy cars? What are the pros and cons of each?

I've been to a couple Indy 500 races and I'm an engineer so I'm fascinated by the technology in Formula 1 cars and Indy cars but I also don't know much about them, particularly the differences between the 2 types of cars.  Is one "better" than the other?  What makes one better than the other on a particular type of track?  What differences exist as far as the technology in the car goes?  Which one is faster and why?  Which one can take a turn better and why?  What driver skills are emphasized in one vs the other?  Etc.

[Assistant] On a road course, an F1 car would smoke an Indy Car.  F1 cars are more powerful (around 800 or so HP compared to 550-700 in Indy Cars) and they have much more leeway with their Chassis and aero.  Indy cars are much more of a "spec" car compared to F1 cars.  They all use a common basic chassis and one of two engines.  In comparison, F1 teams have their own chassis designs and more engine manufacturers.  This creates a lot of Innovation in F1. Indy Cars will hit higher speeds than F1 cars in some races simply due to what tracks they race on.  Indy car races are often on ovals (such as the Indy 500) where they can nearly run flat out for a whole lap and are geared for higher top speeds.  F1 cars have slower top speeds due to their gearing--They won't hit their top speed on many parts of a track due to lack of long straightaways so they have closer gear ratios to maximize acceleration on the straight parts of the track they have.


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

[User] [the boys] can the supes unionize?

[Assistant]
In the comics it's possible but not practical as almost all supes operate with some level of legal protection and income provided by vought American. Trying to unionize would leave them without reliable income and open to legal repercussions. Vought in the comics is also all too happy to send it's heroes on extended secret missions or interplanetary expeditions for PR reasons when in reality they murder the upstart supe before they become a liability.

In the show supes are completely dependent on vought for survival with everything about them owned and trademarked by vought. We see with mesmer that vought can ruin a supes life if it's no longer of use to them. And their entire lives are built around Vought functions so even without vought directly supporting them they're unable to use their powers for money without paying a tithe to Vought.


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

[User] ELI5: Why are gun scopes always on the top of the weapon? Doesn't this make it so the bullets are going lower than where you're aiming? Or does recoil make up for this?

[Assistant]
Scopes never provide perfectly consistent aim over varying distances. You zero in a scope by adjusting it so that what you see in the crosshairs intersects with where you wish to aim **at a specific distance**. Obviously before that distance the bullet will be too high, and past that distance it will be too low.

Snipers and hunters learn to judge distance very well, so depending on how far the target is they can adjust their scope. Scopes can also be adjusted side-to-side to account for wind.


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

[User]
[Paw patrol] Is Mayor Humdinger actually the mayor of anything?

He is very proud of his title, but seems to spend most of his time in Adventure Bay. We never see any other residents of Foggy Bottom (other than Harold and the cats) so who voted for him? I know Mayor Goodway isn't exactly the picture of competent governance but at least Adventure Bay has an infrastructure and a population.

[Assistant]
We once see their basketball team, the Foggy Bottom Boomers. They're all human, even if none speak during the episode, so there's at least a population of five kids.

Still, the place must be real shitty since Humdinger spends all his damn time in Adventure Bay instead.


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

[User]
Eli5: If creatures such as tardigrades can survive in extreme conditions such as the vacuum of space and deep under water, how can astronauts and other space flight companies be confident in their means of decontamination after missions and returning to earth?

My initial post was related to more of bacteria or organisms on space suits or moon walks and then flown back to earth in the comfort of a shuttle.

[Assistant] With wide enough boundaries, they can't. If a tardigrade, or mad space bacteria, can survive a ship going from the vacuum of space to re-entering earth's atmosphere at enormous heat and then being barracked by the thick earth asmosphere ,then there's nothing that can reasonably be done. It's considered sufficiently unlikely to not be a realistic concern.


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

[User]
[WH40] An Emperor level person is born, now what?

So its clearly possible to create an emperor like individual, even in primitive conditions. So lets say we have some backwater planet, insignificant to the imperium. They pay the tithe and the guardsmen and whatever else is asked, staying well below the radar.

A whole bunch of the local phyckers put their heads together, literally and a year later this person is born.

So:

* When does he/she come to the imperiums notice?

* How does the imperium react?

* What position / job / fate awaits this person?

* What, if anything changes with the status of the emperor?

[Assistant]
The Imperium notices.  The black ships cross the whole breadth of the Empire searching out newborn Psykers, bringing the weak to feed the Astronomicon, and training the strong in how best to serve the Empire.  Neither of these fates are acceptable to the new Emperor, who breaks free from whatever bonds the Imperium places upon him.

Next come the Inquisitors, hand-picked to deal with what is the most dangerous young Psyker the Imperium has come across in millennium.  They attempt to purge the young Emperor, but are instead made to kneel before him.

The order of Exterminatus is given, and a fleet of ships comes to purge the planet he lives on.  With a thought, he steps from the surface of his world to the bridge of the flagship of the fleet.  It is his to control now, the beginning of a glorious new Empire.

From this seed grows a new Empire.  The stars are washed with blood in quantities unseen since the Horus Heresy.  The whole of the Imperium is first split asunder, and then regrown under his command.  After the final battle, the new Emperor arrives on Holy Terra, sweeping aside the custodes like a gnats before a hurricane.  He stands before the old Emperor, and smiles to him like an old friend.  He only speaks the words, "Thank you for all you've done.  You can rest now, the Imperium is safe."

The old Emperor finally crumbles beneath the weight of forty thousand years of life, and the new one takes his place as the new Emperor of mankind.

Later, he falls to chaos, and everything goes to shit.


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

[User] [Comics] Many superheroes believe killing, even in self-defense, is an uncrossable moral line. Does this mean they believe police, soldiers, or those who've killed abusers in self defense are morally irredeemable?

[Assistant]
In most cases police and soldiers have the authority of the people and a set of rules, guidelines, and oversight (flawed as they may be)

A great deal of superheroes get their justification and authority from themselves and thus have to hold themselves to a higher standard because no one else can.


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

[User] ELI5: Why isn't it possible to wring a cloth completely dry?

[Assistant]
Water, at the molecular level, forms attachments to fibers that are absorbant like cotton. The small weak forces keep the water attached and prevent you from physically removing it by trapping it and also providing it a haven. You can't compress the fibers with your hands hard enough to squeeze the small pockets where the water resides and remove them.

So between the cotton being a good absorbant and your lack of physical strengh required to manually remove the water, some will inevitably remain. Even in a "dry" shirt, there is still ~1-3% moisture in the shirt at all times due to the cotton absorbing water straight out of the air or off your skin.


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

[User] [Star Trek] What actually happens when somebody is hit by a phaser?

[Assistant]
At the lowest settings, it just creates a burning/stinging sensation.

Low to middle settings, it disrupts your nervous system, causing one to become stunned which can mean knocked silly, or straight up knocked out.

Higher settings: either killed with body intact, meaning the internal organs were damaged by something like an intense burn or shock.

Highest setting: the most cruel fate, being disintegrated. The stream of particles causes your bodies molecular bonds to dissolve instantaneously.


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

[User] ELI5: If a one time infection by certain viruses (e.g. chicken pox) usually leads to immunity, why can other viruses recur in the same person countless times?

[Assistant] They can't, but what happens is that what we call the common cold for example isn't one virus. It's dozens and dozens of different strains of roughly the same virus. When you get sick and then heal from the cold, you have immunity against that particular strain. Not against the hundreds of others one that are still out there.


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

[User]
ELI5: How do they get babies in movies and tv shows to "act"?

I was just watching a Breaking Bad episode where the baby starts crying and then she stops and I started wondering how they get babies to express the emotions they need.

EDIT: Most times the babies arent even looking at the camera angle or at an awkward spot, but they seem to be looking where they also should.

[Assistant] It's similar to how you get a baby to smile when getting pictures done. If you need them to cry, a little pinch works. If pinching babies isn't your cup of tea... have the mother leave the room, wait until they are hungry or tired, and so on.


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

[User]
ELI5: If microwaves are tuned to the resonant frequency of water, why is it that heating up a bowl of soup results in the bowl being so hot it burns my hand while the soup itself remains tepid?

Writing this as I'm nursing a sore hand and eating cold soup.

[Assistant]
In physics there is a concept called specific heat.  It is a measure of the amount of heat energy it takes to raise the temperature of a substance, specifically the amount of energy it takes to raise 1 gram 1 degree centigrade.

It happens that water has easily the highest specific heat of any common substance you are likely to find in your home, including anything a bowl is likely to be made out of.  The water in food may actually absorb more energy from microwaves than the container, but still heat more slowly because the container takes far less energy per gram to increase in temperature.


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

[User]
[Star Trek] Was DS9 really over gunned for a space station?

We see DS9 take on whole fleets of ships on her own and at least stalemate them.  Was she really over gunned for a space station considering her strategic placement and distance from the rest of Star Fleet or was every Star Base that powerful?  The only other installation we see that man be as powerful is Tiger-Kor where they mention you could pound it for days with a fleet and it would stand up.

[Assistant] DS9 had to be OP, because of where it was stationed. In between a civil war and at the edge of known space. They literally had threats coming from everywhere, at any time. Also where else would you want to test your theoretical experimental weapons of war. Where no one of any note might be missed, and the Federation had plausible deniability.


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

[User]
[Pokemon] Why isn't Charizard considered a dragon? I mean...it's a reptile, red, has wings, horns and breathes fire. How is it NOT a dragon?

Oak needs to get his shit together. This thing I'm flying around on that's spitting fire at everything is a goddamned dragon. I don't care what his fuckball Pokedex has to say about it. Mr. Matchstick is a dragon and I'm tired of him being slighted.

[Assistant] That thing you're *fly*ing around on that's spitting *fire* at everything is obviously a flying fire pokemon. Pokemon can't have three types. Also, it's weak against water. If it were flying dragon it would be strong against water, and if it were fire dragon it would be neutral.


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

[User] What do swordfish use their sword for?

[Assistant]
There is some debate over how the sword is used to hunt. In a study on swordfish in 1981:

> ... swordfish rise beneath a school of fish, striking to the right and left with their swords until they have killed a number of fish, which they then proceed to devour

Swordfish are also different from other fish with spears on their heads, such as marlins and sailfish, since their "swords" are dorsoventrally compressed (i.e. horizontally flattened). This suggests that they use their swords not for stabbing but for slashing laterally.

Source: Palko, Barbara Jayne, Grant L. Beardsley, and William Joseph Richards. "Synopsis of the biology of the swordfish, Xiphias gladius Linnaeus." (1981).


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

[User] How do mineral deposits like veins of ore form? Why don't elements mix homogeneously in the Earth's Mantle?

[Assistant]
Earth is covered in segregation processes.

Even the mantle is not well mixed; mantle heterogeneity is a big field in geochemistry.

Different minerals have different properties, so different physical and chemical processes can preferentially move, deposit, or ignore them.

Take gold placer deposits; take a whole bunch of rock which might ocntain some gold. Gold is generally unreactive and much much denser than the rock. So when it gets eroded along with other rock and transported down a water course the gold gets deposited in the bedload and works its way into what are known as placer deposits. In contrast, the rocks are more mobile so get passed downstream more easily, and far more broken down by transport and chemical weathering.

Veins are a product of fluid movement; the crust has lots of fluids in it, and many of those fluids are hot. As they pass through rock as groundwater they will dissolve things into them, and certain minerals and chemicals dissolve more easily than others. As voids allow fluids to cool and collect those solutes can be deposited, resulting in mineralised veins. Now, most veins are filled with uninteresting stuff like quartz or calcite, but in the right environments they can be enriched in all sorts of other minerals.

And so on and so on. Geological processes almost all act to separate something from something else in some way.


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

[User]
[Jurassic World] Would have John Hammond been severely and extremely against the creation of the Indominus Rex?

John Hammond cared about making people happy (despite terrifying and killing a few) and he wanted to bring back amazing animals and let the world enjoy them but would he have greenlit the Indominus?

I know he couldn't see what was wrong with brining back creatures that died millions of years ago, so would he have even seen the major problem with mixing together 2 of the most dangerous predators? and ontop of that mixing in DNA that makes The creature basically a perfect predator? or would he have been strictly "natural" if you will even call what he did natural and say no to the Indominus and that it breaks the natural law? again making Dinosaurs in the first place is breaking the natural law atleast in that Universe.

So would he have been extremely against it's creation and any other hybrid creation?

[Assistant] Book Hammond would have been pissed he didn't get to cash in the hybrid dinosaurs himself. He cared little about the lives under him or ethical concerns so long as he made a profit. Movie Hammond prior to the first film would be worried about the safety concerns of the hybrids around guests but still focus on the financial issues more. After the first film he'd see them as a dangerous abomination and unworthy of existing. He champion hard for their destruction or at least total isolation from other species.


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

[User] Microwave ovens work by exciting water molecules in food. What other substances can be excited by a microwave oven?

[Assistant]
Many substances can be heated in a microwave oven. The mechanism behind microwave ovens is called *dielectric heating* and it requires what are called *polar molecules*. A polar molecule is a molecule where the distribution of positive and negative charges isn't the same and there are parts of the molecule that have a net positive or negative charge.

A polar molecule, like other molecules, is still neutral as a whole, but it has a distinct positive and negative part.

When a polar molecule is exposed to an electromagnetic field, the molecule will rotate to align itself to the field. If the field oscillates, the molecule will constantly swap between rotating back and forth. While it's doing that, it will repeatedly push and bump nearby molecules and thereby increasing the average kinetic energy of the molecules in the substance (and thus the temperature).

This mechanism works with all polar molecules. Water is a polar molecule, but so are fats and sugars. The effectiveness of the microwave oven depends on how skewed the distribution of negative and positive charge is in the molecule. This is quantified as the *dipole moment* of the molecule. A molecule with a greater dipole moment will react more strongly to the microwaves than a molecule with a small dipole moment.

Note that, unlike what some people assume, microwave ovens aren't configured to a specific frequency that makes them work on water. The process of dielectric heating works with electromagnetic radiation of various frequencies. And even microwave ovens don't all use the same frequency. Consumer models typically use 2.4 GHz, whereas industrial devices operate at higher frequencies (10 GHz).


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

[User] Is there any link between density and viscosity of a fluid? Does the density of a liquid influence how viscous a fluid is our vice versa?

[Assistant]
There is no correlation, either direct or inverse.  Mercury is very dense (13.5 g/mL) but flows easily at room temperature.  Polyethylene has a density of 0.9 g/mL, but doesn't flow at room temperature.  How about the other direction?  Gasoline has a density of \~0.8 g/mL, but has very low viscosity.  Uranium (19.1 g/mL) is a solid at room temperature.

Viscosity is predominantly correlated with intermolecular (or interatomic) interactions.  In organic materials, it mostly has to do with weight average molecular weight, although there are many other factors.

Note that rheology (the science of viscosity) is enormously complex.  It is essentially a separate area of science.  When you say something is more or less viscous, you need to describe how you measure it.


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

[User] [Star Trek] Why are the main hulls of federation ships saucer shape?

[Assistant] The shape of ships in Star Trek have a lot to do with keeping the warp field stable and efficient and the specific shape of ships for any given species depends on the sort of warp technology that species has. For the Federation that shape was a saucer but as their warp drives got faster they changed into ovals and arrowheads.


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

[User]
ELI5: Why does an oven auto-clean with no problem and leave behind white ashes, but a dirty grill that is overheated can cause a scary-ass fire?

Isn't the principle the same? Heat to a high temp and turn the grease to ash? An oven can be cleaned easy-peasy one afternoon but the porch will be damn near burned down that evening.

[Assistant]
Your oven should have significantly less grease in it than a grill.  If you're getting that much grease into your oven, you're doing something horribly wrong.  Your oven should have, at worst, some bits of food or cheese or a *little* bit of grease that will burn out quickly.  But grilling usually involves dripping fat and grease all over the place.

Also, your oven is somewhat closed, so there's less oxygen to feed the flames.  But mostly there should be less grease and fat.


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

[User]
[Firefly] Why do bars use holographic pooltables if there's a chance of ball failure?

Wouldn't it be cheaper, more reliable, and more realistic to just use actual pool tables and balls?

[Assistant]
Prevents theft.  Good pool balls are hand-made and cost a good bit of coin - a single set is cheaper than the projector, but they have a tendency to "walk off."  By the time you've replaced 'em a few times, your wallet will wish you just bought the projector.

Plus, a pool ball held in the hand is quite a weapon, and are easy to throw.  It's safer to have them not able to leave the table.


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

[User]
CMV: Just because someone does not actively advocate for a specific issue or voice there opinion, does not make them part of the problem.

I have seen multiple family members get called out for not posting certain things on social media in regards to the current black lives matter movement. They are told they are part of the problem and are bad people for not actively advocating black lives matter.

I see it that someone just living their life normally and voicing no social opinions about the oppressions that go on in this world as being okay and normal. I find it hard to believe that everyone can advocate for all the wrong doings in the world. I am sure that most members of the black lives matter movement dont advocate for problems in other countries actively such as Hong Kong, Iraq, or any other place that dont effect them. People tend to advocate for things that effect them which is okay, but is also not okay for not advocating things that dont effect them. Lebrun James comes to mind for advocating for BLM but expressing ignorance for Hong Kong.

Change my view.

[Assistant] "You are with us or you are against us" is a powerful tactic in some situations.  It allows you to obtain active support from people who might otherwise not offer that support.  But then those people's support is contingent on "with us or against us" remaining the rule.  If friends of the coopted people remain uninvolved without punishment, it makes the coopted people more likely to withdraw their active support and spend their efforts on things they may care more about.  Thus, a person in the right demographic who doesn't actively advocate for the cause in question will tend to take away active support from others as they can more easily get away with not giving active support, and thus hurts the cause.


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

[User]
When to use automated tests and when can you use them?

I'm familiar with manual tests, but now I'm learning Django and the concept of automated testing came up. Is this something that is only for frameworks or can I do automated testing on any project?

[Assistant]
Automated testing is for everything. Not just libs/frameworks.

Imagine this: you have a part of code that is accessed throughout your application. You do some changes to it. Everything seems to work fine. A month later you see that some part of your application doesnt work as expected anymore. You track it down to said code and the changes you made. How could you have prevented that? Automated testing/unit tests. You would have seen that your changes lead to some code not working as expected anymore the second the tests were run.


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

[User]
Some time has passed since my on-campus interview, is it time to assume that another candidate was chosen?

I had my on-campus interview two and a half weeks ago. I was the first of three candidates, but it's only been one week since they interviewed the last of the three candidates.

Should I be worried, or is this somewhat normal? I don't know if it's just due to how long it's been since I personally had my interview, or if I should face the facts...

This was my only campus visit out of my skype interviews, so it's stressful.

edit - to add a few more details, when I asked about the timeline they said they would be interviewing the other candidates the following week, and that it would be a few weeks before I heard anything. I sent my thank you's to each person I met with soon after the visit.

[Assistant] I would wait at least two more weeks before being nervous. The pace of academia is sooooo slow. Imagine how many people need to approve on a hire - a committee, a dean, sometimes even a provost; if there is start-up involved then there are other considerations. HR may need to confirm that everything was legit. Every one of those offices could delay for a week based on being out of town, or busy, or whatever. If you really need to know you can write a thank you to the person who you clicked with most and ask if they know the timeline for letting the candidates know. Good luck!


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

[User] If I'm in an environment with abnormally high humidity, would I require less water to keep myself hydrated, or what would happen?

[Assistant] It really depends on the temperature of the environment; in a hot environment you need more water, especially when the humidity is above the dew point. The heat and high humidity will a) make you sweat more since it's hotter. b) your sweat won't have as great a cooling effect since the water in your sweat won't evaporate fast enough in the high humidity to cool you down. c) since your still hot even after sweating, your body will continue producing sweat hoping that it will eventually cool itself off. So the net result is you're hot, you're sweaty, and if you don't drink enough water, dehydrated from sweating so much.


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

[User]
Is lightning on earth bright enough to be seen from the surface of the moon?

Lightning can definitely be seen from space, and there are many pictures of this. Is lightning big enough / bright enough to be seen from as far away as the moon? If you were an Apollo astronaut standing on the surface of the moon looking at the earth, would you be able to see the flashes of thunderstorms on earth?

[Assistant] Lightning on the *night side* of the Earth can be seen from the orbit, yes. The problem is that seen from the moon, Earth has phases just like the moon, and the dayside is almost always at least partially visible, its brightness drowning out pretty much anything happening on the nightside. And when Earth is "new" or a narrow crescent, it's going to be close to the sun in the sky so no luck then either.


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

[User] [DC] Would Black Canary be stronger if she had a microphone, megaphone, or some other sound-amplifying device?

[Assistant] A commercial microphone or amp is likely not able to emit the sounds she can. Theoretically if one of her super science friends built one that could handle her frequencies then it would massively increase her area of effect.


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

[User]
[LOTR]What did Gandalf exactly do when he hit the bridge with his staff while facing the Balrog?

During the scene, he says his famous line and slams his staff down at his feet, creating a loud crackle. As soon as the Balrog advances, the bridge crumbles, stopping right where the staff hit. What is the nature of this spell? What school of magic could it be in? Can it crumble more than just bridges? How about fortifications like walls or battlements?

[Assistant]
Magic in LOTR doesnt really fit into spells or schools of magic. Its wielded as an extension of the ancient power inherent to the world. Gandalf as a wizard is of a superior class of beings that are older and know of the old rules.

Its not a school of magic or a spell, it is Gandalf enforcing his will over the Balrog and the world local to the bridge. He isnt casting a ward or a rune or anything he is simply tapping into his natural power and announcing that YOU. SHALL. NOT. PASS.


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

[User] CMV: If the law becomes trans-friendly enough, it would be advantageous for me to change my legal sex to female.

[Assistant] If society ever reached the point where you could change genders with the stroke of a pen (though it probably never will), it will probably also have reached a point where there are no longer special benefits to being a woman, or gendered restrooms/locker rooms at all.


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

[User] ELI5: Why does your stomach sometimes rumble when you are hungry?

[Assistant] Things inside the stomach are constantly shifting around and moving down the line toward the final stages of digestion. When your stomach is empty or closer to empty, all that movement of material sends out vibrations in the form of sound waves that reverberate more loudly because the acoustics of an empty belly are better than the acoustics of a full one.


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

[User]
Current Ph.D. student going through a divorce  general advice & publication name advice needed!

Hi everyone,

I am between years 1 - 2 in a 3-year social sciences Ph.D. (need a masters to enter) and my husband and I are filing for divorce.

Relevant details:
1. We have a toddler who goes to daycare full time.
2. He was being unfaithful with my close friend, so there is significant emotional distress.
3. I am currently on my advisors grant for the summer.

Personal details aside, I am wondering how to compartmentalize all of this and push through so that I can finish what I need to this summer. A lot is up in the air (especially ability to stay enrolled full time given that our stipend is so low).

Additionally, my advisor has been wonderful and supportive but has asked me to really think about my publication name. I have 5 conference presentations under my married name. I could easily switch back to my maiden name for my paper submissions (happening in the next few months) but when I changed my last name, I made my middle name into my maiden name.

Any and all advice is really welcome.

[Assistant] Use whatever name you want. Its not like youre 15 publications in. If you want, add something like Firstname Lastname (Marriedname) to your email signature for a year until people get used to it. Use ORCID if you can, and dont worry about it. Of all the things stressing you out right now, let this one be the easy thing. Sorry you have to deal with it. :/


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

[User]
ELI5: What is bitterness, really?

I've looked through tons of ELI5 questions on bitterness and the majority seem to accept "bitterness" as this abstract concept that simply exists, like if you were trying to explain what wind looks like. As a cook and bartender, I enjoy bitter foods daily - amari, bitter veggies, grapefruit, lemon pith, coffee. I can go on and on. I know what it tastes and feels like.

But what is it, on a chemical level? Why do so many poisonous or even unnutritious things taste bitter? How do our taste buds pick it up and what is the "bitter" signal sent to our brains? Why is it neutralized to a degree by other specific flavors?

For an alternative and extended answer to this question, can you extrapolate on this? If humans publicly and consistently accepted and appreciated bitterness in foods, would we continue to have a nature-based aversion to bitter foods, or would it be seen as a generally desirable characteristic? Sugar and salt are the most obviously sought after, but appreciation for acidity is becoming more and more common and I wonder about the effect of marketing and publicity as a means for changing perceptions of flavor.

**In short, is perception of bitterness as a negative (less desirable) flavor largely or even completely driven by environmental influence?**

[Assistant]
Bitterness is perceived via an assortment of taste receptor proteins, the TAS2R family. It's hard to predict from the structure alone which substances activate those receptors, but generally a lot of secondary plant metabolites do, and a lot of those are a defense system by the plants and thus toxic. At the core, it's an avoidance mechanism to prevent you from eating stuff you shouldn't eat.

You'll notice that kids don't like bitter stuff, not at all. They are even more sensitive to it, which plays into their dislike for certain vegetables. However, we humans being smart, we figured out that there is bitter stuff we can eat safely and came to like it - but that is pretty much always an acquired taste, learned behaviour overriding the innate preferences.


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

[User]
At what point does someone stop sleeping and start being in a coma?

Do they get pronounced to be in a coma after one day? Two? Or is it the circumstances under which they fall asleep?

[Assistant]
A person is considered to be *comatose* if they, for a period lasting **longer than six hours**, cannot be awakened, don't respond to external stimuli, lack a normal sleep-wake cycle and do not act voluntarily.

(source: Weyhenmyeye, James A.; Eve A. Gallman (2007).Rapid Review Neuroscience 1st Ed. Mosby Elsevier. pp.1779.ISBN0-323-02261-8.)


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

[User]
[MCU] [Dr. Strange 2 spoilers] Why can't Wanda...

It seems like the ability to instantly deform/destroy some part of a person's body is a potent skill. Wanda uses it to disable Black Bolt (which then kills him), but it seems like it could be used on anyone who opposes her. Is there some reason she didn't use it on Dr. Strange, for instance?

>Mr. Incredible: Wanda, this is Dr. Strange, the person who's been trying to stop you for the past 90 minutes. He may yet succeed due to the fact that his heart is beating, his lungs are able to pump oxygen into his blood and he is not in a state of brain death.
>
>Wanda: What heart, lungs, blood and/or brain?

If the answer is, he can defend himself magically, or she didn't actually want to kill him due to their history, is there some reason she couldn't or didn't want to do it Captain Carter or Captain Marvel and chose instead to have a lengthy fight with each?

[Assistant]
I took it as arrogance, possibly Darkhold induced.

Wanda humiliated each of them when fighting them.

Black Bolt; she took away his greatest weapons and let him kill himself with his own power.

Cpt Carter and Cpt Marvel are brawlers, they win fights through pure power and fighting prowess, so Wanda just beat them down with overwhelming force.

Professor X is a master manipulator, literally the master of mind games. Wanda let him in to her mind and then destroyed him psychically.

Mr Fantastic is stretchy and incredibly intelligent, so she just pulled him apart like a cheese string before he had any further opportunity to strategise.


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

[User]
[Avatar: The Last Airbender / Legend of Korra] Are souls simply a kind of spirits reincarnated (usually) forever or are they something different in substance and nature?

The world is made of earth, fire, air and water with spirits being kind of something else but are souls something like spirits or are they specified to really be distinct in nature?

I know that a few people have escaped the cycle of reincarnation and basically became spirits so I'm curious about what that really means.

[Assistant] Every person has a spirit that contains their consciousness, which can be thought of as a soul. If they are skilled enough, they can travel to the spirit world, leaving their mortal body behind. Upon death, a person's spirit is reincarnated, and they lose their consciousness, unless they have some sort of tether, such as the Avatar. Whether or not it passes on to some other plane/realm is unknown. Some, like Iroh, choose to leave their mortal bodies behind and continue to exist as spirits in the spirit world, and are not reincarnated.


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

[User]
How strong is Beast Boy really?

I hear a lot of talk about how beast boy could potentially be the strongest character. Able to take the dna of other races and species and mix n match to his whim. Like taking kryptonian and martian dna, fusing it with a t rex and giving it wings. I dont know if that is true but it sounds badass. If it is, how strong can he get? And why doesnt he use his powers to the max?

[Assistant]
We don't actually know if he could combine multiple species DNA in one thing, but we do know at full power he can potentially:

1. Take on the forms and powers of any living creature including magical creatures and sentient alien species.

2. Become multiple creatures simultaneously. (For instance he has turned into swarms of bats and insects a few times.)

3. Retain full human intelligence in forms that couldn't possibly sustain it. (He has been viruses and bacteria before. The virus thing could be very significant, given that they're not exactly alive, much less animals.)

Taking all of these into account at once, there are some pretty terrifying possibilities with his powers.


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

[User] Why do many Asian demonyms end in "-ese" (ex: Burmese, Vietnamese, Japanese), while many Western Hemisphere demonyms end in "-an" (ex: American, Mexican, Chilean)? Why don't we say Americanese, or Vietnaman?

[Assistant]
The -ese ending is hardly limited to Asia. There are Sudanese and Portugese, to name two.

The ones ending in -*ese* in English actually come from Italian. Recalling that Marco Polo and other Italian traders were the first Europeans to reach the Far East, it should be no surprise.


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

[User]
ELI5: What causes us to not say to ourselves "this is totally unrealistic" in dreams?

Why do we lose our sense of reality while dreaming? Not once during my dreams do I think "it doesn't make any sense that I'm able to fly right now."

[Assistant]
When we fall asleep, our brain activity is sharply lower than it is during the day: and while parts of your brain may still be functioning while you sleep, you **usually** don't have access to advanced logic in your dreams.

However, it is possible to realize you are dreaming, and lucid dreaming is a thing some people practice. Lucid dreaming involves, oddly enough, tricking your body into being asleep, while most of your brain stays "awake" in a sense.


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

[User]
ELI5:What does it mean when a city is incorporated or unincorporated and why do they post signs stating "Blank City Corporate Limits"?

I see signs in my travels stating "Blank city corporate limits" what does it mean for a city/town to be incorporated or unincorporated and why are the limits of it important?

[Assistant]
An incorporated city has a charter from the state and a proper municipal government that exercises powers within the boundaries of the city's incorporated area.

An unincorporated area is not a city. It doesn't have a municipal government, and is governed as part of the county in which it is located.


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

[User]
[Marvel] Why did the Soviets turn Bucky into the Winter Soldier?

As opposed to someone who was a Russian and already loyal to their government, and requiring brainwashing to make him from just an experiment in super soldier juice to an actual fighting unit?

[Assistant]
I've just recently read that Bruebaker's run, and essentially it was a combination of circumstance and malice - when Bucky was picked up by Russian submarine, he was essentially braindead or something like that, so when they revived him he was a blank slate, not much brainwashing was required. His muscle memory was intact, so basically a murder machine with amnesia literally fell into their hands.

Secondly, a KGB officer who actually picked him up and spearheaded the Winter Soldier project was personally familiar with Cap and Bucky, and carried a degree of spite towards him, after Cap berated him for shooting wounded nazis in the head after the combat engagement. So personally for him it was very satisfying to take one of (literal) american poster boys and turn him into loyal Russian agent.

Brainwashing was added later down the line, when the project was already well under way, after it became apparent that Bucky starts recovering his memories while on the missions. THEN they've started shocking him in the brain.


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

[User]
Can you become immune to strains of bacteria?

I was under the assumption that you only become immune to viruses, but not bacteria. Is that true, and if so why?

[Assistant]
You can definitely become immune to strains of bacteria.

Immunity is subdivided into two categories: innate and adaptive immunity.

Innate immunity are those features of our immunity that are static and use a somewhat "generalized" approach to protecting the individual. This includes things like the Toll-like receptors and mannose binding lectin that have broad specificity for different types of pathogens, including bacteria.

Adaptive immunity relies on the production of antibodies. Antibodies are globular proteins encoded by genes the have what's called a "hyper variable region".  A staggering array of mutations occur in these regions during development of a newborn, giving rise to a large array of B cells encoding antibodies that are each unique to a different antigen and expressing it on their surface. In a process called clonal selection, B cells expressing antibodies that bind to proteins from yourself are killed off, otherwise an autoimmune disease develops. Once clonal selection occurs, any antigen that binds to an antibody on the surface of a B cell (including antigens on bacteria) will trigger a cascade of responses in which the B cell starts multiplying and the B cells start excreting the antibody they encode. These antibodies can then start binding to pathogens and mediating the adaptive immune response.

The concept of "gaining immunity" refers to priming/activating B cells that encode antibodies that bind to a specific pathogen. When an antigen binds and activates a B cell and initiates the adaptive response, some of the B cells that proliferate are fated to become so called "memory B cells" that persist at higher levels in the blood stream to allow the body to start responding to the same infection much faster during subsequent exposure.

If an antigen from a bacterium activates its cognate B cell and stimulate formation of memory B cells that encode antibodies specific to the bacterium, you've gained immunity to it.


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

[User]
[MCU] Civil war. Questions concerning the accuracy of Vision (Spoilers)

Tony blames Vision for missing his shot and hitting Rhodes with Visions laser beam. It appears to be implied that vision misses because his judgment is clouded due to his love for Scarlet Witch.

I don't know what anyone could expect from Vision. The Laser was apparently on track to hit Falcons wing suit. Falcon was able to see the laser coming (obviously the laser wasn't light speed). After Falcon dodged the laser, it proceeded to hit Rhodes.

Other than knowing that Rhodes would be in his cross hair, what could Vision have done?

Is Tony's blame towards Vision chalked up to Stark being is usual emotionally stable self?

[Assistant]
> Is Tony's blame towards Vision chalked up to Stark being is usual emotionally stable self?

No. It's chalked up to Stark being reasonably and expectedly emotionally distraught at the near-death and paralysis of one of his closest friends.


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

[User]
How can any CD or DVD be re-writable?

I understand that a laser is what write information onto the disk making microscopic indents of information so how can these indents be erased and more information be stored on the disk?

[Assistant] Actually, that's not how *burned* CDs are created. Pressed, or manufactured, CDs do have  microscopic indents in them, but writable and rewritable CDs and DVDs actually use a photosensitive dye- in the case of rewritable discs, a dye that can be reset back to its initial reflectivity.


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

[User]
How do some things get absorbed through lung gas exchange (Nicotine) but others don't? (Tar)

I'm essentially wondering how lung gas exchange works for substances other than air. Obviously anything besides air is going to be bad for the lungs but how? Does it leave a film like buildup? Is it permanent? How does vaping compare to regular air?

[Assistant] The chemicals in the tar are not very soluble in water (blood) and they tend to interact with each other more than water making it difficult to separate tar leading to a build up. The immune system has to remove the tar, which leads to inflammation and cell proliferation and long term it can facilitate the growth of tumors. Vaping has no tar, but it does have oils that can build up in a similar way. Long term effects of vaping are still largely unknown, its likely better than smoking but still far from healthy and possibly even more addictive.


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

[User] Would a one-photon-thick beam of light be diffused after reflecting off a convex mirror?

[Assistant]
There's no such thing as a "one-photon-thick beam of light". Photons are not little balls that can be perfectly lined up into a one-wide beam. Photons are quantum wave/particles that act mostly like waves when traveling and mostly like particles when interacting. So, to make sense, your question should be changed to: "Would a very thin beam of light experience divergence after reflecting off a convex mirror?" The answer is yes. But if the beam width is small compared to the radius of curvature of the mirror, the mirror is going to look very close to flat to the light beam, and the divergence will be small. As the beam width gets thinner and thinner , and the mirror stays constant, the beam divergence after reflection decreases.

Something you also have to keep in mind is that light beams diverge on their own because of diffraction even before reflecting off of a convex mirror. There is no such thing as a perfectly collimated beam of light. So if you tried to make the light beam infinitely thin in order to get exactly zero divergence after reflection from a convex mirror, you would get complete natural divergence of the beam due to diffraction.


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

[User] ELI5: When electricity goes to ground, what actually happens to the electrons?

[Assistant] Sending an electron to ground is comparable to dropping a water droplet into the ocean. It becomes part of the global network but on its own it will have a minimal impact due to the vast size of our globe. Ideally you should be able to send as much current to ground as you want without ever changing the electrical potential. However in reality it is a bit more complex. Your ground wire have some resistance, inductance and capacitance and you might therefore see some transmission line effects when sinking currents into the ground. Similarly the ground itself is not an ideal conductor, in fact it can be a very poor conductor in a lot of cases, and you could in practice change the electrical potential of the local ground if you have enough current. This is something you might see around rail lines and during thunderstorms.


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

[User]
Vulcans are obviously smart, but is Spock exceptionally smart as far as Vulcans go?

It seems as though a lot of Vulcans serving on the Enterprise D weren't as intelligent, or as highly ranked, as their Terran counterparts. This makes me wonder about the first officer of the original Enterprise. I know Spock is smart, but would he be considered a genius on Vulcan?

[Assistant] Vulcans are exceptionally logical, which also makes them very risk-averse. Therefore, they tend to follow "safer" career paths. As a result, few Vulcans rise very high in Starfleet. Spock is more ambitious than most, due to his human heritage.


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

[User]
[Superheroes] Does Doctor patient confidentiality extend to superheroes?

If someone like Spider-Man went to the ER, would their identity be safe?

[Assistant]
There's actually precedent for this when celebrities are hospitalized. They're quietly checked in under a fake name for obvious reasons (all of which boil down to, "let's not give them a reason to sue us").

Legally, a superhero's identity would be *pretty safe* because the hospital/GP wouldn't want to get sued for damages for revealing a secret identity. However, there are some caveats:

* Doctors are required by law to report gunshot wounds.

* A doctor or nurse could still leak information to the press in exchange for a big sack of money, and may or may not get caught.

* If the superhero is wanted for any crimes (like, say, vigilante justice) the hospital would have to comply with local law enforcement.


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

[User] ELI5: Why does night vision have a greenish tint?

[Assistant] The image created by night vision is black/white.  Human eyes are most sensitive to green light.  Since you're in the dark and it takes your eyes time to adjust to light/dark, you only want to make the image as bright as necessary.  So the image is given in green to make it more comfortable to view in the dark, possibly for long periods.


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

[User]
[DC, Marvel] Who's worse, Thanos or Darkseid?

Morally speaking of course.

[Assistant]
Darkseid by a country mile after an airplane across the Atlantic.

Darkseid is. He wishes to rule over the entire universe and in doing so crush the meaning of life, hope, and will. He is a dominating evil that's true form is so powerful he has to exist as avatars in every universe.

He has no redeeming traits and the only times he's ever done anything remotely kind or just it was in self interest.


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

[User]
[Bloons TD4/5]Why is it so difficult for ground troops to see camouflaged bloons?

It appears as though the camouflaged bloons are not well hidden from my point of view as I command my troops. I don't have any kind of special goggles, and yet, I can see them plain as day.

It also seems that they are easily visible from a high vantage point, such as my own, or from the spy plane, or the monkey Buccaneers crows nest.

 from our point of view, they're just bloons that shouldn't be so hard to see from the ground. can someone explain this!?

[Assistant] You're looking at the bloons against a backdrop of the path they're following. Your ground forces are almost always looking at them against the backdrop of the surrounding foliage, which is what their camouflage is designed to work against.


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

[User] ELI5: What determines if a plant is a fruit or a vegetable?

[Assistant]
It depends on the context since different words mean different things in different contexts.

In botany, fruit refers the part of a flowering plant that has seeds. Things like apples and pears are botanical fruits, but so are tomatoes, cucumbers, legumes, and eggplant. The thing that makes them all fruit is they come from flowering plants and contain the seeds from that plant.

Vegetable is not a botanical term.

In cooking, fruit usually refers to any part of a plant that tastes sweet and is often eaten uncooked. A vegetable is usually any part of a plant that is savory and is often eaten cooked.

There are some legal classifications for foods too that may be different than the above definitions. For example, imported vegetables might be taxed differently from imported fruits and the law would just have to have a list of what counts as a fruit and what counts as a vegetable. Or it might matter for meeting nutritional guidelines (this is where "Congress said pizza sauce is a vegetable" comes from).

So a tomato is a fruit botanically speaking, but a vegetable in terms of cooking. On the other hand, jicama is not a botanical fruit, but it is a culinary fruit.


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

[User]
How do smart phones track battery percentage?

One thing I've always wondered about is, how do smart phones with, say, Li-Ion batteries track their remaining life and report them to the operating system as a percentage level.

I should imagine it would have something to do with the current millivolt level of the battery, but seeing as to how sensitive those electronics are, it seems unlikely to me to expect a large enough deviation from the standard volt level of the battery, without disrupting the actual workings of the device, so that you could establish, for example, 3923 - 3925 mV is 10% battery.

I'm sorry if this has already been answered or if this isn't the correct subreddit for this question.

[Assistant]
Generally in the case of smart phones, manufactures typically rely on a coulomb counter embedded within the device to measure the SoC.

Coulomb based measurement would be determined by measuring the current flowing from the device/battery, which in tun would be subtracted against the reference battery capacity to provide a percentage of battery life remaining.

I would be more than happy to explain further if you would like additional details.


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

[User]
[Final Fantasy] Why are martial artists doing so much damage?

I'm a white mage, and I'm in a party with a knight, a ninja, and a martial arts master.  We're pretty badass.  We just defeated Tiamat, which was no easy feat with no offensive spell power except that one lightning gauntlet we found in the castle of ordeals...which I really don't have time to use because I'm always healing somebody!

Right now we're on a random dungeon crawl with outrageously hard bosses but tons of easy nuisance monsters and everyone in my party is doing crazy damage to everything!  We just fought a band of 4 goblins like the ones we killed as newbs in the forest outside Cornelia and each of the damagers in my party are inflicting at --minimum-- 15x the amount of damage it took to kill the same monster back when they were a threat to us.

I mean, the ninja will decapitate one blue goblin in a single strike, and then cut off each appendage from the corpse and leave the whole graven package neatly skewered on a nearby tree branch.  Now, it's really cool that he can do this all in about 15 seconds flat, but once you've seen it about 80 times, it seems like overkill.   The master will hit a madpony with a paralyzing blow and then shatter every other major bone in its body with a serious of acrobatic and strength achievements that inspire awe...but again, far beyond the point at which the threat was terminated.  Our knight is far less elegant, but equally over-effective.  He just carries the biggest, sharpest sword he can find and bashes it into everything while grunting desperately until the creature is nothing but a fine red paste (or green, or purple, depending on what they bleed).

As a guy who'se always conserving spell points and preparing to need more as dangers grow, I wish my comrades would realize it's a marathon, not an exhibition.  Why are they so overzealous in attaching weaker monsters?!

[Assistant]
As a mage, you get better with study, but martial types need practice.

What you see as overkill, they see as a chance to practice techniques in real world but low stress situations. Drilling the techniques when they can pay attention to each muscle twitch means that they are perfected when fighting for their lives and needing to focus on tactics.


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

[User] ELI5: Why do fan and propeller blades often have different shapes and angles of attack? Why does the number of blades vary, shouldn't there be an optimal design?

[Assistant] There *is* an optimal design... for any given purpose and set of operating conditions.  The problem is that such things as expected air pressure, the speed at which it's moving forward (in the case of a propeller), the amount of driving power available, whether or not the fan is ducted, and various others, will change the optimal design.  Hence, different designs for different purposes.


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

[User]
Is it possible to completely contain light? Say, in a room designed to trap light particles could you turn on a lamp then shut the lamp off and the room stay lit?

FYI I have no idea how light particles work.

[Assistant]
If you had an emissivity of 0 i.e. a perfect mirror, which doesn't exist.  Each time a photon is absorbed/emitted, there's going to be loss of energy as heat.

Moreover, if you had a room that worked like that - you would be unable to walk into it, since your body would quickly absorb the light and emit it as IR with an energy loss as heat.


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

[User]
[Star Trek] What would've happened if Nero had gone through the red matter black hole and came out in the Mirror Universe?

What would've happened if Nero's ship had gone through red matter black hole and came out in the Mirror Universe? What would've happened year later when Spock arrives? Would a situation like the one in the Enterprise series when they find the future ship happen again?

[Assistant]
**Wall Of Text Incoming**

Captain George Kirk of the I.S.S Kelvin receives information that a "lightning storm in space" has opened six light-years from his current position. Starfleet is concerned that it may be caused by rebel activity in that sector, possibly the testing of a new, secretly-developed weapon. Kirk is ordered to investigate and take whatever action he deems necessary to protect the Empire.

The Kelvin arrives at the designated coordinates just in time to see the Nerada emerge from the storm. Before the Kelvin can hail the new arrival and demand an explanation for its presence in Imperial space, the Nerada opens fire.

Unfortunately for Nero, the Terran Empire is more technologically advanced at a much earlier stage than the Federation was. They didn't tolerate the Vulcans patronizing humanity and artificially restricting their tech level for decades, but rather conquered Vulcan and forcibly took all of their advanced technologies. They presumably do this with all species they encounter, as evidenced by Mirror Archer's Suliban cloaking device and his successful plot to steal the future-version of the U.S.S Defiant from the Tholians.

This means that the I.S.S Kelvin is a far more dangerous foe than Nero anticipated. It fends off the attack and cripples the Nerada. George Kirk's MACOs beam over and subdue Nero and his crew, making up for their 3-to-1 strength disadvantage against the Romulan miners with superior military tactics and discipline.

Nero himself is placed in the ship's agony booth. Despite hours of the most gruesome pain imaginable, he doesn't give his captors any information about who he is or where he comes from, other than moaning Spock's name during the few moments when his captors turn off the booth to prevent him from dying from sensory overload.  The name means nothing to Kirk and the torture continues.

In the meantime, Kirk's crew have done a cursory examination of the ship and determined it as Romulan in origin with unknown modifications centuries beyond what the Romulans are known to be capable of. It's at this point that a few crew members try to mutiny against Kirk, hoping to pull a Hoshi Sato, seize control of the Nerada and use it to crown their leader Emperor.

In order to short-circuit the mutiny, the MACOs loyal to Kirk enter the brig and kill the surviving Romulans so the mutineers can't try and strike a deal to return them to Romulan space in exchange for control of the Nerada. This is successful and the mutiny is put down.

An unfortunate side effect of this tactic is that Kirk himself now can't use the Nerada to take over the Empire. Instead, he sends a report to Starfleet Command, who despatch a carefully vetted admiral and fleet to tow the Nerada back to Earth for reverse engineering.

George Kirk returns to Earth a conquering hero. He gets a medal pinned on his chest by the Emperor and a promotion to Admiral.
Nero spends the rest of his short, miserable life howling in agony in a Starfleet Intelligence black site as his captors try to wring precious drops of knowledge of the Nerada's systems from him.

Prime Universe Spock arrives in the Mirror Universe one year later to find a fleet of highly-advanced Imperial starships waiting for him. Realizing that his chances of successfully escaping are low, he detonates the orb of red matter aboard his ship. His last thoughts are sad and regretful.


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

[User] Does food actually soak up alcohol in the stomach?

[Assistant]
Sort of. It really just slows down its absorption.

Alcohol can diffuse across all tissues and barriers throughout the body, so ingested alcohol ultimately ends up spread all over your systems. However, the faster it gets from your stomach to your intestines, the faster it is absorbed to your bloodstream and spread everywhere, so you get drunk faster (as your alcohol concentration in your nervous system peaks more acutely).

Having food in your stomach delays gastric emptying - the dumping of stomach contents into your small intestine. This, in turn, delays alcohol absorption, so your blood alcohol level (representative of your alcohol level throughout your body) rises more slowly, not getting you as drunk as quickly and giving more time for your liver to process it.

Actually, even with no food present, this also happens when mixing alcohol with sugary mixers which delays gastric emptying (as opposed to sugar-free mixers). So, although food does actually technically "soak up" alcohol in the stomach, what actually slows down getting drunk is just slowing down how fast the alcohol-infused contents go through your digestive system.


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

[User]
Could payment be made obsolete, even partially, if all the things exchangeable by participants in an economy were cleared algorithmically?

I'm no expert on economics, but it seems that if such a Bitcoin-like algorithm existed, value would not necessarily have to be carried by currency. For example, it could be expressed by sets of coefficients in a sum over all exchangeables: "2L milk per week for a year, or one iPod touch, or $100, or..." Each participant may have a different programme of consumables valuation, against their own producibles or against a currency. Minimum standards of living could be maintained by introducing charity instruments.

Intuitively it seems it should work better in small, self-reliant communities than in large cities, but it might also work well in the underground economy.

What don't I understand here? What would be a best case/worst case effect of such a system being adopted anywhere in the world right now? Are there any books that illuminate this topic?

[Assistant]
So an alternate medium of exchange, used to fill in for actual cash, for use in small, self-reliant communities?  Sounds a bit like company script used in old mining towns.

What would the benefit of this type of system be (except to the persons in control of it)?  Why not just use money?


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

[User]
ELI5: How do they know what chemicals your brain is producing in response to certain stimuli when it should involve opening your head to watch it?

They say that the brain releases dopamine when X happens, or releases oxytocin when X happens, etc. How do we know that's happening inside somebody's head without cracking their skull open?

[Assistant]
Mostly indirect evidence, eg. we know that X is swirling around your brain because we took a blood sample and its high in Y which corresponds to X in scenario Z. Alternatively, we injected you with X which makes Y light up on your brain scan while we show you pictures of your parents getting handsy.

Sometimes semi-direct evidence, like having brain cells in a petri dish and observing them respond to stimuli or chemicals.

Sometimes also direct evidence like actually having a rats skull open and continuously probed as scientists(hopefully) feed the rat sugar or something.

All of it builds a knowledge base which is used to make accurate observations via indirect evidence.


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

[User] ELI5: Why are India and China so densely populated?

[Assistant] Both areas have stable climates, good soil, plenty of water and of course, rice. Per square mile rice has a very high yield and can be grown in many places, as long as you have enough water for it. Rice is also very labour intensive, which would incentivize rice farmers to have very large families, which they also had no trouble feeding thanks to their amazing rice.


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

[User]
[Star Wars] Why were Obi-Wan and Anakin always paired together even after Anakin was no longer his padawan.

One thing I couldn't help but notice while watching The Clone Wars and other prequel era material is that the Anakin and Obi-Wan are still constantly being sent on missions together even though Anakin's no longer his padawan. Other Jedi don't seem to work with their former padawans as often as Obi-Wan does. Is there any particular reason for this?

[Assistant]
They work well together.

More than that, though - there's a war on. Obi-Wan Kenobi is one of the three or four most skilled swordsmen in the Jedi order. Anakin Skywalker is one of the two or three most powerful Force users in the Jedi order. Together, they're basically an elite strike squad who can be sent in where any lesser Jedi would be expected to fail.


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

[User]
CMV:Creating new children in a world where there are kids who need to be adopted is selfish and morally wrong.

The human race, like any other species, has evolved because of our desire to procreate. At this point in our species' development we are able to recognize that this urge is a primal one and can be resisted. Humanity has spread all around the world and is plentiful to the point of having children that are unwanted by their original parents. These kids need parental figures in their life and there are people who desire to have children. Shouldn't those who desire to have children help those who are without parents? To create more children just out of the desire to spread your own genes is selfish in my opinion. Also we have developed ways to have sex without procreation, so that primal desire can be sated without creating more children. I don't think this view should be legally enforced, but I do think that it should be more widespread. It seems though a lot of people view the idea of having children different than I do so I'd like to see if my own logic has flaws in it.
Edit: While on the topic of having kids how do you guys feel about the ethics of procreation if climate change is past the point of no return? Is it okay to create children that will suffer through resource wars and environmental disaster?

[Assistant]
There are currently about 680 thousand kids in foster care in the US. There are about 74 million children in the US. That puts foster kids a little less than 1% of the total child population. That number to me sounds about as optimal as you could realistically get considering that 1% is spread across the whole of the country.

Think of it like unemployment. 5% is considered full employment even though that is obviously not 0. There will always be some adults in transition or unable to work. There is no real way to get that 1% much lower because there will always be some children born and put up for adaption.

There is also a strong argument for the vetting process most agencies go through. These kids have some extra need for stability beyond what is considered normal. There is a good chunk of adults that shouldn't have kids in general, much less a child that has already lead a particularly difficult life.


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

[User]
ELI5 - in light of all our advances in wireless technology, why are printers still such a pain point in operating with devices?

I know that things are much better than they used to be, but given the seamless integration we have across so many other devices these days, both hardware and software  I feel as though the amount of average technical issues we face with printers to this day is much higher than it should be.

[Assistant] The problem isn't technology, it's standardization. Look through your list of print drivers and there are 1000's. It's hard to make anything work with that large of a group, especially when they are all doing their own thing. Until a market leader emerges and standardizes the system, printing will be a pain.


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

[User] [BSG] In BSG the captain says "Set condition red throughout the ship" in emergency situations. Is condition red ever set for only specific parts of the ship?

[Assistant]
It would be unusual, but possible.

An emergency situation on the flight deck, for example, might get serious enough to warrant a condition red there, but not for the entire ship.  Imagine something like a fuel spill and ignition, maybe.

You might get something similar in engineering spaces: a localised emergency that doesn't threaten the entire ship but does warrant a high degree of awareness and specific procedures in the immediate vicinity.


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

[User]
My defence is in just under 4 weeks and I'm very anxious. Any tips?

My slides are ready, I'm just practicing and thinking of possible questions. Every minute I'm not working on them or the questions is racked with guilt/anxiety for "not studying". Any tips on how to prepare? Thank you in advance.

[Assistant]
A word of encouragement, rather than advice.

Your defence is the best conversation you will ever get to have about your dissertation.

All those arguments you've had at conferences ... parties where you've been boring people to tears by talking about your research ... your advisor paying just enough attention to make relevant responses ... your pharmacist staring at you blankly as you rant about citation stylesheets -- those conversations were just try-outs for *the one really good conversation*.

You get to have a chat with people who have really made an effort to get to grips with what you have been wrestling with for years. They'll actually have *paid attention to what you're saying*. And that can be awesome. Even if you become famous and get interviewed on the Late Show, the people there aren't going to be as interested in your work as the people at your defence will be.

OK, sure, they'll have criticisms. But they'll also be more invested in your work than anyone else in the world that isn't you. Make the most of it!

To get this far, you must like talking about your work. You like ranting about your research? Well, here's your chance!


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

[User]
When the sun goes red giant, will any planets or their moons be in the habitable zone? Will Titan?

In 5 billion years will we have any home in this solar system?

[Assistant] While Saturn will be in the habitable zone and Titan along with it you have to think of how these worlds will be affected by the increase in temperature. The average density of Titan suggests it is a good mix of rock and ice, so with an increase in radiation from the sun, most of the methane will be lost to space and the ice might melt, but that much ice may mean a water world (covered in ocean). Titan is tidally locked to Saturn and orbits ~16days, so its days are ~16 Earth days. This would mean wild temperature variations between day/night sides. Also, Titan does not have its own magnetic field so maintaining an atmosphere is not promising. It does get some protection from Saturns mag field, but it also ventures outside of it and gets blasted by the solar wind.


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

[User] ELI5: How is a nuclear missile flying over another sovereign nation's airspace not deemed an act of war?

[Assistant] It could certainly be provocation for a war that other states see as reasonable. What matters isn't the act itself, it is how others respond to it. If nobody wants to make war over it, then it doesn't matter what some legalistic definition might say.


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

[User]
ELI5: Where does the energy from the engine go when my (automatic) car is stopped?

This is actually a question my friend asked me, but I had no idea how to answer so here I am. Basically, if my car is stopped, the engine is still running. Presumably, things in the engine are spinning and moving gears around and whatnot. At what point does that energy stop going to the tires (if at all?) Is there some mechanism for discarding the excess energy produced while the car is stopped?

[Assistant]
the disconnect is in the torque converter, 2 fans that face each other, 1 turned by the engine, the other connected to the transmission.  they can slip by each other, forcing the fluid through the other fan without it spinning.

Ultimately, that energy is converted to heat in the transmission fluid via friction and then expelled through the transmission case/transmission cooler to the atmosphere.


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

[User]
[Inside Out] How do the emotions manage to choose who is the leader of an individual's mind?

Joy seems that is Riley's mind leader; the mother, Sadness; and the father, Anger. This is based on who is in the center most of the time and how they interact each other. There's no doubt that the parents were like Riley as kids, happy the majority of time, but because of experiences or choices up to maturity, somehow, any emotion but Joy took charge in the Headquarters now that they are adults.

Are the leaders chosen based of how many memories stored during the individual's lifetime?

Who would be Riley's leader during her teenage years and adulthood?

Are there possibilities that Joy still be the leader during the teenage/adult stage?

[Assistant] I do not think there is a "leader" emotion, emotions take the control panel depending on which one of them thinks it will be the most useful in a given situation. Over time, one emotion being in charge long enough creates a certain lifestyle for the person they lead, and thus the chosen emotion is needed even more, in a self -feeding cycle.


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

[User]
CMV: It's impossible to truly stay anonymous on the internet

I believe that, no matter what steps you may take, in the end it is impossible to stay private on the internet. This is because, even if you go through the effort to use a VPN or even TOR, that it is still possible to break the encryption and thus find out your identity and thus personal information. Similarly if you use duckduckgo as a search engine, the websites that you visit will inevitably track you (I'm looking at you, Facebook and Google) across those sites. Forgetting about industry for a second, even worse is government initiatives such as the PRISM program, where every bit of internet communication is logged, encrypted or not, so even if your internet usage is private now, sooner or later it'll be cracked (if they want your information).

[Assistant]
Here's how you do it.

* Go to the gas station, get a burner phone with Internet service.
* Pay for the phone with cash.
* Go do whatever you need to do on the Internet
* Destroy the phone.

They will never know who did it.   This isn't much different from the old days when you'd put coins in a public telephone.


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

[User] [STAR WARS] If the republic had 10,000 venators and there was a separatist blockade, like the one on Ryloth, why doesn't the republic just send, like 400 venators?

[Assistant] The Republic may have 10,000 Venators, but they have to defend around 1,300,000 planets. Even if we assume each system has 8 planets, and that the 1.3 million is total planets as opposed to habitable, that still gives us 162,500 systems to defend. That means that each Venator is responsible for defending approximately 16 systems. So to commit 400 Venators to break one blockade, you are leaving around 6,500 system undefended.


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

[User]
[Harry Potter] What is the tactical value of Hawks Head Attacking Formation?

It seems like it leaves the ball-carrying chaser exposed and without an outlet pass should they get pressured by the defense.

[Assistant]
Primarily intimidation. All three chasers flying directly towards you, your first instinct is to get out of the way. Of course, this is less effective against higher skilled players, but there are other benefits. The lead Chaser can quickly hand off the Quaffle to either of the "wings," creating scoring opportunities. The Chasers can also break formation and split up. In a sport that operates in three dimensions,   getting the opposing team's Chasers to go the wrong way can be a massive advantage.

Basically, Three Chasers, three hoops, one keeper. If the Keeper can't keep their eye on the ball, it's an easy goal.


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

[User] Our Sun and Moon appear to us to be the same size in the sky. Thinking about it my guess would be that the scenario is extremely unlikely. Is it?

[Assistant]
Yes, it really just seems to be an extremely unlikely coincidence. The Moon is receding, so it's not even true in the distance past, and won't be true in the distant future. The Moon used to be closer than now and appear bigger than the Sun, and eventually will be quite a bit further away than it is now, and will appear smaller than the Sun.  So we're not just in a lucky place, we're in a lucky *time* too.

This means that the eclipses we have on Earth are very odd. Usually, an object will either block out the Sun entirely across a large part of the surface for a long period of time, or will "transit" across the surface of the Sun, only partially obscuring it. The Earth-Moon system is weird in that we have total eclipses, but only in a really tiny slice of land and for a really short amount of time.


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

[User] ELI5: People keep saying that Gary Johnson only needs to win New Mexico to become president. How is this possible?

[Assistant]
*If* Gary Johnson Wins New Mexico, *and if* Clinton and Trump happen to win just the right states so that neither one has a majority of electoral votes, then the house of representatives gets to decide who is president.

In that case, they could choose Johnson.


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

[User]
[Star Trek]What was the most important decision made or action undertaken by any member of Starfleet during any of the TV shows or movies?

The final episode of TNG is excluded as that one would win hands down and then the question would not be very interesting. So anything related to that from previous episodes is also discarded.  Everything else is fair game.

And if not the most important, what are some of very important ones? Ones that stand out.

[Assistant]
Tasha Yar deciding to go back with the yesterday Enterprise, thereby giving them the tactical expertise they needed to last long enough in the battle to be detected by the Klingons, who then learn that humanity has a sense of honor and thereby plant the seeds for the alliance between the feds and the empire.

Either that, or Sisko tricking the Romulans into entering the Dominion War.


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

[User]
What is meant when people say "when boomers will be retiring this decade, they will cash in their portfolios, causing a credit crunch"?

Peter Zeihan (among other writers) speaks about an oncoming "credit crunch" which goes like this - boomers are the largest population cohort. When they retire (and no longer have steady salary) they will "cash in" their portfolios (made mostly of stocks) into fixed-income securities retirees prefer like bonds.

When people retire, does the process of diverting capital from high-risk growth stocks into low-risk solid investments happen automatically by some pension fund? Does it always happen, or do some retirees keep their stocks? I'd love a higher resolution on this often mentioned topic when experts disucss the financial implications of changes in demographics.

[Assistant]
Stocks empirically have significantly better returns than bonds IF you're able to sit out the volatility of stock valuations fluctuating up and down. That's a big if, and if you're young the general idea is that even if you take a 30% hit today on your net wealth this year, hang around for 5 years or so and that will recover comfortably. You'll probably be alive for another 50 years or more so why not.

If you're a retiree, you don't really have that luxury. You're nearing the end of your lifespan, so waiting 5 years just for your wealth to recover to where it used to be could be 50% of your remaining lifespan. In the meantime, you've got a lot more bills that need paying and no other source of income except your investments and savings. The prudent thing to do is to sell your stocks and buy safer investments.