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

[User]
How does your brain determine whether a sound is loud enough to wake you up?

It must be different for people, since there are light and heavy sleepers.

[Assistant]
Sound feeds into the brain's arousal pathways, in the reticular activating system. It is a weak input (vision is much stronger), but it is there. The sound inputs will activate reticular activating system neurons, which will "turn on" the brain by sending acetylcholine to the thalamus and activating the Nucleus Basalis to send acetylcholine to the cerebral cortex. The thalamus is likely to be the more important target, though.

The reticular activating system is in different states of suppression in different phases of sleep. The sound level necessary to wake someone changes dramatically depending on where they are in their sleep cycle.


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

[User]
CMV: Capital Gains should not be its own separate tax but should instead be as a part of one's income

Pretty self-explanatory. We should not have a separate tax bracketing system for capital gains and that any income made off of capital gains should be considered part of one's income. Having separate rate and bracketing systems (especially today's) seems to only advantage those who are already rich and powerful. Today's capital gains tax rates are much lower than the tax rates for income. While I have heard it argued that we could make those rates and brackets the same, it still doesn't make sense that we have two separate rates of taxation that from a practical perceptive simply allows already rich and powerful to pay a lower effective tax rate than they would if their capital gains were considered as a part of their income and then taxed as income.

If there is something that I am missing about capital gains I would like to be informed on that. Also, if it was not clear, I am referring to the United States.

[Assistant]
A couple points that i think have not been mentioned yet.  First is that there may be a misunderstanding in your post regarding the brackets. The normal brackets tax income up to a point at one % and then all income above that bracket is taxed at the income of the next bracket.  That is not how capital gains brackets work.  The capital gains bracket that all of you capital gains are taxed at is tied to your income tax bracket.  For example, if your ordinary income is  $39,375 or below, there is no tax.  Above that and up to $434,550 it's 15% and above that it's 20%.  These are all in fact lower than the ordinary, but it's an important distinction to make that it's not it's own bracket.

The second point is how capital gains actually work.  Capital gains accumulate over time but are generally reported at a singular event.  If a stock appreciates from $1,000 to $2,000 over 10 years, you earned $100 per year on the stock, but report a gain of $1,000 in year 10.  That's pretty tame, but if you apply it to something like a business that you started with $100,000, work on it for 9 years and are bought out for $1,000,000 you will suddenly have gains of $900,000 in a single year.  Ignoring all other income, that $100,000 of earnings per year which in ordinary terms puts your annual tax bill in the 24% tax bracket. However if we used ordinary income brackets for the $900,000 gain you would be well within the 37% tax bracket on more than half of that income. There's time value of money and standard/itemized deductions and other income to factor in but in simplest terms it's also trying to mitigate the effects of these single year spikes.


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

[User]
Instead of free college tuition, could we regulate tuition prices by simply making colleges provide and collect all student loans?

As it is right now, banks provide and collect the majority of student loans across the country, there is very little risk for them because the debt is only dropped with death. If America introduced legislation that made all student loans provided by and collected by the schools, they would bear the brunt of the risk/reward. It would seem to me that the schools would then be incentivized to make sure the tuition and loans did not exceed the value that the program provides. It would be a much riskier proposition to leave students 200,000$+ in debt with 12+% interest, if the schools were the ones at risk of not being paid. In my opinion this seems to be the "capitalistic" solution, because colleges that produce students more capable of paying back their loans (better product), would then grow with the market & be able to increase the tuition at a reasonable rate.

Would this be a feasible solution? Why? Why not?

[Assistant] Ceteris paribus, banks would be no more likely than schools to issue loans for which there was not a positive expected return.  It is highly probable, in fact, that their risk assessment is significantly more accurate than what would be the assessments of individual schools, given the sophistication and experience of lending institutions.  By issuance or non-issuance of these loans, and the rates at which they're offered, banks exert the same incentivizing force for schools to provide effectual education.


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

[User] ELI5: If smell is based off your nose reacting to particles, how do predators like sharks smell, for example, "a single drop of blood from over two miles away"?

[Assistant] They can't until some of the particles travel the 2 miles to reach them.  But they can detect very low concentrations of particles, so it doesn't take much for them to notice it, and then they can locate the source.


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

[User]
Humans and chimpansees diverged some 6 million years ago. This was calculated using the molecular clock. How exactly was this calculation made?

Please be very specific but understandable to laymen. I want to understand how divergence dates are estimated by use of a specific example.

[Assistant]
Molecular Clock Hypothesis tries to estimate how far apart organisms are evolutionarily by means of using specific proteins. Some proteins, such as cytochrome c (present in almost all organisms) seem to have a fairly consistent time between neutral mutations, meaning that if most mutations are neutral (have no effect on fitness), and if they occur at more or less regular intervals, you can estimate how many new mutations you should see in a generation.

Thus, by measuring the number of mutations in that protein from the time when two now distinct species had the same or very similar versions of these proteins, one can theoretically estimate the time these species diverged. There are several limitations of this process, like fossil prevalence, generation time and metabolic rate, among others. So while it may not be a perfect process, it's not without its uses.


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

[User]
Would any doctor really accept a blood donation from somebody who had just run 26.2 + 2 miles?

I heard this talked about on the news. It seems to me that while heroic, it also sounds like a downright TERRIBLE decision to go give up a liter of your blood after running in a marathon.

The blood is important for circulating oxygen, and I have to imagine that a runner's body must be very oxygen deprived after such extended physical exertion. If they have less blood, won't they be even more susceptible to fainting than marathon runners already are after the race?

Furthermore, wouldn't a hospital have enough blood on hand to need donations there at the time?  Donated blood must be tested for diseases and whatnot before it is transfused, so even if the hospital did not have enough blood on reserve, it would not be able to use the blood from the runners but instead blood probably brought in a helicopter from another hospital in Boston.

[Assistant]
I was wondering the same thing.  Probably not a good idea, but the reasons are varied.

You would have to consider first the risk to the marathoner (donor), and then the person receiving their blood.

The risk to the marathoner would be great.  Throughout the course of the race, their bodies have accrued an oxygen debt that needs to be "repaid" as they recover.  While their muscles have tried to continue aerobic respiration to the greatest extent possible, there is likely to be a large amount of circulating lactic acid from anaerobic respiration. That lactic acid will be combined with oxygen in the liver to reform glucose.

While there is a very effective buffer system in place to maintain blood pH within a range, decreased pH (increased acidity, increased conc. of protons) from the lactic acid, as well as increased body temperature and partial pressure of CO2, will slightly lower hemoglobin's affinity for oxygen, making it a little harder to repay the oxygen debt.  The runners are also likely dehydrated as well as deficient in plasma electrolytes (hypokalemic, etc.).  Essentially, their bodies are working hard to re-equilibrate their chemical balances, and losing blood volume would make that more difficult by decreasing their capacity to exchange gases as well as redistribute various compounds to the tissues where they are needed.

That being said, on any old NON-race day, a marathoners would be able to handle the loss of a pint of blood much better than less athletic people, as they likely have a higher hematocrit and cardiovascular systems that are more efficient.

As for the safety of the recipient, they would probably be unaffected because usually donated blood is fractionated into erythrocytes, platelets, and plasma.  It is probable that lactic acid and other wastes would be removed and the pH adjusted. Also, during a MCE (mass casualty event), hospitals gather together their supplies of O- blood (universal donor) that can be pretty safely given to anyone.  All the marathoner would be doing is replenishing the supplies they used that they already had on hand.  It's unlikely that WHOLE blood donated right then and there would be used for an emergent case.  If that somehow were the case, post-marathoner blood would be a BAD idea because acidosis is part of the "trauma triad of death" that leads to death in trauma patients.  The lactic acid in the donated whole blood would exacerbate the acidosis and probably decrease their chance of survival.


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

[User]
[Supernatural] Why do the supernatural, deity like, teleportating, basically god like creatures fight so stupidly?

The angels get into it with the demons, the demons with the Winchesters, Amara with God, and so on and so forth, it's all just shoving, punching, kicking, and weapon brandishing. Why isn't there more teleportation, and insta explosions? More instant neck snaps, an force chokes?

[Assistant] You see that sort of stuff when two beings of varying powerlevels fight.  Lucifer instagibs plenty of angels and demons for example.  When you get beings of similar powerlevel, that stuff doesn't work as well.  A demon can't just explode another demon, even if they can explode a human.  Think of it like having a will save / resistance.  When they are resistant to each others powers like that, the punching, kicking, and weapon brandishing is what's left.


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

[User]
CMV: Trump's Twitter ban is the perfect spark to a much needed conversation about social media influence

If 10 years ago, you were to tell the average American that the president of the United States were to be banned from using social media platforms that has billions of users in 10 years, you would be called crazy, and rightfully so. It should be horrificly frightening that our public discourse has gotten this bad which warrants censoring the sitting president of the United States.

With that being said, this breaking of eggs can make a good omlette. The public is now having a lot of conversations about legal protections social media platforms have and the vast amount of power they have and whether or not they should have that power to begin with.

Its funny how we're not okay with business monopolies in many industries but in terms of social media, we seem to be okay with just a handful of private companies being in charge of a lot of our public discourse.

[Assistant]
Do you understand the context in which these people are being banned? If 10 years ago you told people the President could be credibly accused of inciting insurrection - or that a sect of conservatives thinks Democrats are a cabal of election stealing child rapists, you'd also be seen as crazy. But that's what happened.

What should we learn from these recent events that helps us understand internet censorship? That it's good to keep the dangerous crazy people off high traffic social media.


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

[User] Why do some helicopters have 2 blades whilst others have 4 or 5?

[Assistant]
The greater number of blades in a helicopter enables it to produce more lift, hence heavier helicopters, such as Sikorsky CH-53 has more blades.

However, there will be trade offs from having more blades. The helicopter blades produce a wake of turbulence behind them, reducing the efficiency of the subsequent ones, resulting in a need to space them out sufficiently to prevent the turbulent wake from affecting the performance of the other blades to much. Furthermore, a greater number of blades will also complicate the hub, and overall increasing the cost. Hence it is not effective to increase the number of blades in small helicopters.

In order to further increase lift, the blades can be rotated at  higher velocity. Then why can't heavier helicopters just rotate their blades faster? This is due to the tip of the blades limited to subsonic speeds, as supersonic blade tips will create extremely large amounts of drag and turbulence, greatly reducing efficiency. Furthermore, even before the blades reach supersonic speeds, there would be formation of local pockets of supersonic airflow, which also creates a large amount of drag.

Hence, due to turbulence created by the blades, and the inefficiency of supersonic tips, there is a need for more blades in heavier helicopters. Small helicopters are better off with lesser blades to reduce the need for a complicated hub, as well as to save cost.


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

[User]
[General Sci Fi] Sentient Buildings in fiction?

So, I recently watched Disney's Encanto and I have become interested in the concept of sentient buildings. ( This was shown in Encanto's trailer so I don't think a spoiler tag is needed ).

Currently, I know of only 3 sentient buildings in fiction. The First, is the titular Monster House of the 2006 movie ''Monster House'', the second is *''The Oldest House''*, a semi-sentient office/laboratory and containment-facility building in Remedy's 2019 game ''CONTROL'' and the third, of course, is Casita Madrigal in Encanto.

What are some other Sentient buildings in fiction?

[Assistant]
There's Danny the Street in Doom Patrol. He identifies as a butch transvestite (hardware stores with frilly pink curtains, you understand).

Then there's the haunted house in "Grave Encounters" (and a few similar concepts like the Overlook in "The Shining"), The Street in an HP Lovecraft story by that name (it is implied to be sentient and even causes a natural disaster to kill terrorists who are meeting in one of its buildings), Baba Yaga's house in Russian lore...

Doctor Who also once encountered a living city in "Death to the Daleks" (though it didn't have much of a personality)


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

[User] [Star Trek: TNG/Firefly] Out in the black, Serenity, and the USS Enterprise make contact. How does the conversation go between the two captains?

[Assistant]
After Mal reluctantly allows Geordi and Data on board to make repairs, and to upgrade Serenity's engine with a warp coil, the Serenity crew goes onboard the Enterprise for a little rest and relaxation.

Kaylee, overseeing the repairs on Serenity, falls in love with Data for his naivet and good will, but has her heart broken when she finally realizes, *after Data has said all along*, that it is impossible for him to have feelings for her.

Inara falls in love with Picard for his diplomatic skill and sexy head.  After a passionate kiss, Picard insists that he must remain on the Enterprise and that a relationship is impossible.  She smiles and assures Picard that she understands, and that a relationship was never her intention.  Mal flusters about.

Riker is confused that no one is jumping into his quarters, and he finds himself with nothing to do.  He woos a random young female Starfleet officer.  What a cad!

Jayne and Worf have a rousing game of Parrises Squares.

Simon and Wesley Crusher get along really well, as Wes teaches Simon how to play 3-D chess.

River causes shenanigans in the holodeck.  She turns the safety precautions off and fights Worf's training program.  Then, she sets Moriarty loose on the ship.  This calls Data and Picard away from their *activities* to track down Moriarty's program as it ransacks the Enterprise's warp drive.  When they manage to confine Moriarty back into an isolinear chip, the Enterprise and Serenity crews decide it's best to part ways, seeing as the repairs and upgrades are done on Serenity anyway.

Mal shakes Picard's hand and says, "You got a mighty fine boat.  Be seeing you 'cross the 'verse."

Inara waves politely from the transporter pad as the Serenity crew beams away.  After Mal makes some brief remarks about how Inara likes old bald men, Inara returns to her pod on Serenity to light a candle in Picard's name.  She whispers, "Boldly go, Jean-Luc."

Credits.


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

[User] ELI5: Why are milk advertisements for milk in general rather than a specific brand?

[Assistant] In 1993, Californian dairies agreed to put three cents from every gallon sold towards an overall marketing campaign to promote milk.  Since they are all contributing, the ads don't favor one brand over another.


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

[User] When a photon reflects off of a mirror and changes direction, does it decelerate, stop, then accelerate like objects with mass do?

[Assistant] Photons never stop in the sense you're speaking of, so no. A precise view of what happens is rather difficult since we're dealing with a quantum particle; in a sense it interacts with the mirror and takes all possible paths settling on one upon measurement (all the paths add to the quantum amplitude). Some photons get absorbed by the mirror, giving it energy, others are reflected and so on.


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

[User] ELI5: If dolphins and whales breathe through lungs, what are the reasons that make them aquatic? Alternatively, why have dolphins and whales not developed the ability to live in land?

[Assistant]
Dolphins and whales evolved from land going creatures. Over millions of years they returned to the sea. This probably started as hunting along shorelines, and adaptations occured that let subsequent generations hunt further and further out until you have the completely aquatic creatures we have today.

We have excellent transitional fossils from what were four legged animals to modern whales. The nostrils move progressively further back on the head, and the limbs form flippers. Dissections of modern whales show vestigial leg bones buried deep in their bodies.


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

[User] ELI5: Why plates get too hot to touch in the mircrowave but the food can still be cold?

[Assistant]
Some plates get hot in microwaves, and shouldn't be used in them. Other plates don't absorb microwaves and stay cool.

The difference is mainly in the type of clay used to make the ceramic plates (there's also some types of plastic that shouldn't be used in microwaves, but that's another topic). Clays that contain a lot of iron oxide, which tends to make for a dark reddish-brown colour though that may be covered by glaze, are especially bad for microwaving. Plates made from such clay can get very hot, and in the process they absorb a lot of the microwave energy instead of letting it go into the food. Hence, the food doesn't warm up as much as you expect.

Microwaves sort of bounce around inside the oven, reflecting off the metal walls, until they hit something that absorb them. That something then gets heated up. Glass and some types of ceramic (porcelain) are transparent to microwaves, just like glass is transparent to visible light. So if the microwave hits such a plate, it just goes right through and bounces off the oven floor. That wave then has a good chance to hit the food.

Plates made from red clay with lots of iron oxide, or that are glazed with some color made with a lot of metal or metal oxides, are opaque to microwaves and absorb them much like black paint is opaque to visual light and absorbs it. If a microwave hits such a plate, it gets absorbed and heats the plate instead of having a chance to heat the food.


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

[User]
[Star Wars] Is the Force inherently corruptive?

It is much easier to use the Dark Side of the Force. It takes greater self-control and concentration to maintain a Light Side orientation. Even the slightest deviation into the Dark Side tends to completely convert a user to darkness, even dominating a personality that would otherwise not tend toward evil and aggression. This would all seem to indicate that use of the Dark Side is the Force's *natural* inclination, in the same sense that it is easier to work *with* the natural force of gravity (to fall) than it is to fight against it (to climb).

Is there some fundamental aspect of using the Force that more readily lends itself to use of the Dark Side? Is the Light Side is a less natural use for the Force? Is the Force itself naturally corruptive, or even evil?

[Assistant]
It's easier to destroy than build.

It's easier to to criticise than praise.

It's easier to blame other's than look to yourself.

It's easier to give up than keep trying.

The dark side makes things easier.

And it makes you look strong while you embrace your weakness.

But it is individuals who make the choices.


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

[User]
Are there 'micro-sounds' ?

Are there sounds too small/soft for a human to perceive, or to be recorded and played back on conventional equipment? As an (extremely silly) example, is there a sound of the joints on an ant's leg moving, the waveform of which is far too minute for an ear or microphone to detect? Are there non-audible-to-humans methods of measuring such sounds? I would be fascinated to hear about any and all aspecs of this question. Thanks!

[Assistant]
Yes, of course.

If you convince an ant to walk on the membrane of a microphone, you could record the sound of its little legs quite easily. Perhaps use a loudspeaker instead of a microphone (they are interchangeable to some extent), because it has a larger membrane. Seems like a nice science project for a week-end.


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

[User]
[Harry Potter]Has the Sorting Hat ever been 'wrong'?

Wrong is in quotes because it's sorting 11-year-old kids by the trait they most portray at that time. However, from what I've seen so far (FB&WTFT) included, the kids tend to match up pretty well with their chosen houses. (The only exception I'd make are the hatstalls. For example, the Sorting Hat thought long and hard about whether to place Hermione in Ravenclaw or Gryffindor. Also, Harry himself.) After all, it placed Peter Pettigrew in Gryffindor.

[Assistant]
The hat does everything mostly for shits and giggles.

The traits associated with each house are so generic that any kid can show those traits during their time at school.
The rest is just confirmation bias.


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

[User] ELI5: what's the point of "juicing" over just eating the fruits and vegetables as is?

[Assistant]
a lot of people like juicing because its "convenient".  You can make the juice and take it with you on the road, instead of trying to eat an apple and a banana and a handful of spinach on the drive to work.  you know, fruit is sticky and has cores/peels you can't eat and bla bla bla.

also, a lot of people add things that are good for them, but they don't like the taste of, like the aforementioned spinach or kale or chia or whatever trendy thing is hot on pinterest at the moment.  then they can cover up the taste of that thing with delicious and sugary fruit.

BUT the downfall to all of this is that juice is far less nutritious than an actual fruit.  if you throw the entire fruit in a blender, you're ok. but if you extract the fruit, then you're just drinking the sugary sweetness without getting the fiber and good stuff in the bulk of the fruit.


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

[User] [Mount And Blade] Why are the lords alove after 3,000 in game years?

[Assistant]
The nobility in Calradia are a race of immortals, unable to be killed by age or violence. They have used their immortality to rise to power and prominence in Calradia and maintain it.

Not all the immortals are nobility though. Some, commonly referred to as the Companions, are or were commoners.


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

[User]
How do cells stick together?

We are formed of tissues that can be fairly strong! We can't for example take a handfull of our cells easily. How do they stick so well together?

[Assistant]
Cells produce something called an extracellular matrix, which is a dense, complex network of very large proteins which stick to each other. The matrix surrounds the cells, and the cells produce proteins which attach them to the matrix.

All cells do this, and in reality the body isn't just composed of cells holding on to each other - it's better to think of it as a large, resilient protein matrix which cells live inside. If you wanted to reach in and grab some cells, you have to also rip away the surrounding matrix, because they hold on so tightly with their adhesive proteins.


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

[User]
[Star Wars] What happens to all blaster fire that misses its target in space? More specifically in dogfights.

Edit: Thank you all for the replies, my curiosity was satisfied.

[Assistant]
Blasters of all scales are basically just highly excited gas contained by an energy sheath, that sheath deteriorates and the blaster bolt loses its cohesion (and therefore, all danger) over a relatively short distance.

A capital ship in  a planet's orbit for example could hit and do damage to anything on the planet, but it couldn't hit anything on the planet's moon.


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

[User]
Do black holes ever die? Could they intime consume the whole universe

Hear me out, obviously they could only consume where matter is but is it possible that over however long it would take that they could all form one giant blackhole?

[Assistant]
Yes black holes die.  They lose energy by emitting Hawking radiation, and since energy is directly related to mass, they lose mass by losing energy.  Eventually they lose enough mass to not be a black hole anymore.

If they didn't ever die, then in order to consume the universe, the expansion of the universe would have to be slower than the effect of the black hole's gravity.  People have observed with a high degree of certainty that the universe is in fact expanding faster than gravity can pull everything together, so no, that wouldn't happen.


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

[User]
[Asimov] why did humans make robots unable to harm humans?

Killing other people is one of the most lucrative jobs for intelligent robots.

People want robots to replace soldiers, rich people want robots to kill poor people, etc.

[Assistant] The worry wasn't that a human would order a robot to attack another human.  The worry was that robots themselves would decide to attack humans.  Simply put, humanity doesn't think it can win a war against all of robotkind, so they programmed robots to be unable to start such a war.


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

[User] With amber playing such an important role in the fossil record, I can't help wondering why big globs of resin were seemingly so abundant during ancient eras. Can someone explain?

[Assistant] There are plenty of plants today putting out big gobs of resin, it just hasn't had a chance to fossilize yet. The reason amber is so important is because it tends to leave parts of other organisms intact, not because there was much more of it being made than there is today.


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

[User] ELI5: If I were able to attain enough money to hire a team capable of sending me into space, and buy the spacecraft itself, would anyone be legally allowed to stop me?

[Assistant]
Goodness no! In fact, you'd probably get a prize, if you were able to do something novel up there. We're actively encouraging civilian spaceflight through a number of initiatives, including SpaceX Prizes and general tax breaks for corporations even attempting it.

Mind you you'd have to schedule your launch past air traffic control.


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

[User]
[Star trek]Suppose I ask the Holodeck to create a simulation of ...an Eocene Jungle. is the computer simulating all the animals in the jungle From the moment I walk in, or does it just procedurally generate them as I travel around?

So like suppose I've walked 5KM through the Jungle and I come across a clearing with some Propalaeotheriums (horse ancestors) in it. Was the computer simulating them from the comment I walked in, or did it only "decide" to "create" them when I got there?

[Assistant]
The second one. It procedurally generates the terrain you travel through. There wouldn't be any reason to simulate stuff you can't see, and also the holodeck isn't that big.

The weird thing that's never clarified is how it works if two people on the holodeck walk away from each other. It SHOULD only work if they stay in the same area (an area the size of the actual holodeck), but it seems to cover for this somehow.


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

[User]
ELI5: What does decentralized government mean?

People reference this idea all the time without explaining.  What would decentralized government look like  - are they really referring to municipal governments making decisions that are now federal, or is it more than that?

Furthermore, what about decentralized banks?  Another idea I hear people stating then nodding in agreement.

[Assistant] Decentralization is simply the concept of power being spread outing more local, while centralization is the opposite, concentration of power in a single location/entity.  So shifting power from the federal government to the states would be decentralization.  When speaking about banks it's probably means decreasing the power of the US Federal Reserve.


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

[User]
[Tolkien] What happens if a ship tries to follow the Straight Road?

The Straight Road leads to Valinor, where Elves and certain other mortals live forever, and is a leftover from before the Earth was made round.  What would happen if a ship crewed by Men tried to follow it, or tried to sail next to a ship on the Straight Road?

[Assistant]
They would continue to follow the bent road and sail around the world.

It is possible for ships to accidently end up in the Straight Road (see Eriol/lfwine) but it is very rare and not something you can intentionally do.


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

[User] ELI5: How/why does water put fire out?

[Assistant] Water does two things. It cools the burning object by being converted to steam, drawing the energy away and snuffing out the ignition temperature. It also, suffocates the gasification occurring on the surface of the burning object. Nothing actually burns, it's the gas coming off the object that is fire.


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

[User]
[Transforners] Is Megatron just a straight up robot?

Theres no catch or second meaning...hes full-on robot? I can put him on a list with Wall-E, Ultron, CHAPPiE, and Kelex?

[Assistant]
Tricky... You could also ask "is a human a (squishy) robot?"

Transformers are a peculiar species.  Most sentients have well-defined bodies and use tools to make themselves more effective, clothing to adapt to their environment, vehicles or domesticated animals for transportation, and so on.

Transformers have very loosely defined physical structures.  They have a brain, an inner-energon-pump, and a spark case (the Primus-ists among them would describe it as a soul; the scientific would say it's like a routing nexus that integrates the signals from the brain with the energy from the pump).  Those three interconnected systems, as sophisticated as anything you'll find in squishy biology, provide a an individual "skeleton" around which a relatively simple mechanical body is crafted.


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

[User]
The world's oceans are one connected body of water, but there's a significant water level difference across the Panama Canal. Why?

.

[Assistant]
The Panama canal climbs up into Gatun Lake and then descends back down the other side.  The two ends are both at sea level, but the lake is ~85 feet above sea level, hence the need for locks.

The original plan of having a single sea-level canal was deemed too expensive and too slow to build.


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

[User] Why do some sperms swim faster than others? Is it caused by differences in the DNA they carry, or some nutrient variance between them?

[Assistant]
"Boy sperm" swim a bit faster because they are lighter: the Y chromosome is smaller than the X chromosome.

More significant reasons are going to be deformation and blind luck: doesn't matter how fast it is if it swims the wrong way or the tail is wonky, for example.


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

[User] How come the Liver is the only vital organ that can repair itself and grow back? What is the reason for this?

[Assistant]
The distinction of the liver as the only organ that can repair/regrow is a bit misleading.  It is commonly cited as the prototypical self-repairing organ, but in actuality many parts of the body can constantly repair and renew itself.  The basal layer of the epidermis is a great example of a cell type that retains some stem-ness and is able to regenerate skin and provide compensatory responses to injury.  Similarly, adult stem cells are found in many other sites, such as the crypts of Lieberkuhn in the intestines, hematopoietic stem cells in the bone marrow, and even neural precursor cells in the brain.  Admittedly, we don't yet have a great understanding of the roles each of these cell types play in the regeneration/homeostatic process, but we do know that they are much more prevalent than previously thought.

With regards to the liver, it's important to note that true 'regeneration' is not occurring - rather, there is compensatory hyperplasia as the remaining liver tissues receive various chemical signals to proliferate and restore lost hepatic function.  Many other organs, including kidney, pancreas, adrenal glands, thyroid, and the lungs of very young animals, also demonstrate compensatory hyperplasia, but just to a less noticeable extent.  With this compensatory hyperplasia, the surgically resected lobes are not regrown - rather, the remaining lobes enlarge, such that function is restored without restoration of original form.  This is mediated by signalling molecules such as HGF, TGFa, EGF, TNF, Il-6, as well as hormones and neurotransmitters like norepinephrine, serotonin, insulin, thyroid and growth hormone.


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

[User] [Marvel/DC] Which Marvel characters would have a difficult time adapting to life in the DC universe and vice-versa?

[Assistant]
* Drax would have a tough time without Thanos.  Maybe he'd eventually find someone else to arch, but it wouldn't be the same.
* Green Lantern would just be a guy once his ring ran out of juice.
* Batman would struggle, at least on the inside, because of his unhealthy relationship with Gotham.  He's Batman - he could have fixed Gotham years ago.  But he wants it to stay a little sick so it still needs him.
* John Constantine would be thrown for a loop, all of a sudden being in a universe where magic consisted of bright beams of light and 'Eyes of Agawhatsits' rather than dark dealings.  He'd soon find some marks and get on with things, though.
* Reed Richards would receive a stern talking-to from Superman: "look, Mr. Fantastic, stop trying to invent solutions to this problem.  We pretty much just punch things until they go away in this universe, and it's time for you to get used to that."
* Wonder Woman would try to join the Avengers only to be told by Black Widow, "hey, you know the secret rule of female superheroes: only one woman per team.  And what's with the bathing suit?  In this universe we wear pants."


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

[User] ELI5: why is cereal (and dried milk) so hard to clean off a bowl if you let it dry?

[Assistant] It's mostly the dried milk to blame.  Milk is full of dissolved protein, the same sorts of molecule found in eggs and meat.  Dried protein makes a very good glue, and once it's dried it's very difficult to re\-wet and remove.  If you just ate the cereal with water \(an unpleasant thought\) and let it dry, then you'd just be dealing with some residual sugar from the cereal, which would dissolve in water no problem.


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

[User]
Why does drinking methanol (CH3OH) cause blindness while drinking ethanol (CH3CH2OH) doesn't?

Even though the difference between the two is only one carbon.

[Assistant]
The compound causing the blindness is actually not methanol, but formic acid, created from methanol in a metabolic process called toxication. Formic acid is a nerve toxin that acts through damaging mitochondria, and the optic nerve seems to be particularly vulnerable to its toxicity. Though, with doses only a little above the dose that can lead to blindness (that is, about 15 ml), toxicity extends to the whole organism with potentially lethal outcome.

Fun fact: the antidote to methanol poisoning actually is ethanol. Poisoned individuals are being kept at about 1 per mille, for about a week, by means of infusion.


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

[User] Eli5 Why is it more likely to have horrifying or mundane hallucinations when a person has a mental illness, than to have pleasurable or positive hallucinations?

[Assistant] When folks have pleasurable hallucinations, they do not seek mental help, they tend to interpret it as a spiritual experience. In modern western secular culture, if you tell people about a pleasurable hallucination, they just ignore and dismiss it as you making stuff up for attention. Pleasant hallucinations are far less likely to interfere with someone's life.


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

[User]
Is it possible to be in the middle of a recession and not know it?

I known there are lagging and coincident indicators.

[Assistant] many recessions only last 2-3 quarters. By definition, we must have had 2 consecutive quarters of negative GDP growth to call a period in time a recession. During the first quarter you could be unaware you are in a recession, especially since the Feds data doesnt roll in instantaneously.


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

[User] [40k] How exactly did the Imperium know that the Emperor needs exactly 1000 psykers a day and what would be the consequences of only using 999?

[Assistant] The psykers are not "sacrificed" intentionally, no one is cutting throats or preforming a ritual per say. There are hundreds of thousands of psykers that make up the Astronomicon's psychic choir. They just burn out at a rate of about a thousand a day.


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

[User]
ELI5: When countries provide foreign aid (cash) to others, how do they transfer the money?

Do counties cut a big cheque, e-transfer or maybe a cash delivery?

[Assistant]
Most of the world's banking industry is centered in the US at the Federal Reserve.  Every country and just about every major bank has an account with the Fed that contains a significant portion of its assets.  When one country wants to give foreign aid to another its usually just a matter of deducting funds from one country's national account and putting them in another country's.

So for example, if Canada gives Botswana $100 what will most likely happen is Canada will tell the Fed about the transaction and the Fed will transfer that money from the Bank of Canada's Fed account and stick it in the Bank of Botswana's account.

If Botswana then buys $100 of grain from an Italian company they'll let the Fed know and the Fed will then take that money out of the Bank of Botswana's account and move it to the bank that the Italian company uses.

Its likely that no money will actually physically move as a result of this process - its just the Fed changing account balances, similar to if you wrote a check to someone who used the same local bank as you.

There are instances in which countries will try to bypass the Fed's banking system - for example when India buys oil from Iran.  But the countries in these cases typically try to avoid paying in cash, instead they'll do the deal in something like gold or as a barter deal in which they trade one product directly for another.

In the case of India buying Iranian oil they'll just stick the gold on a plane or boat and send it directly to Iran.

You also tend to see similar deals with Russia.  For example, Russia has historically provided a large amount of "foreign aid" to Venezuela.  But that aid isn't in the form of cash, its typically in the form of oil field equipment that they ship to Venezuela and technical services provided by oil engineers that they send to run the equipment.

Likewise, Venezuela has provided a huge amount of "aid" to Caribbean countries.  But the aid isn't in cash, rather its in oil that Venezuela ships directly to them.


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

[User]
ELI5: Why do equivalent notes played on different instruments sound different?

So if an A is 440hz, why does a piano playing an A sound different than a violin, a guitar, or someones voice making that same A 440 note? Its obvious that the pitch is the same on each instrument but each instrument has a distinct sound. Ive never heard an A on a piano and thought, is that a piano or a cello. Why can we distinguish between instruments?

[Assistant] Timbre is the word that describes the quality you're describing. While pitch is the frequency of the note, 440 Hz for A, the shape of the sound wave is not a perfect sine wave. The variation in the shape of the wave will contribute to the quality of the sound.


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

[User] ELI5: FDR's "New Deal"

[Assistant]
TL;DR verison: The "New Deal" was the government trying to help get the country's economy out of a major depression.

When FDR took office, the economy had crashed years ago, and still had not recovered.

The previous president had a "hands off" economic policy that said government should stay out of the economy as much as possible. If people didn't save for their retirement, that was too bad. If people wanted their roads clean and clear, they should take care of it themselves. If too many farmers planted corn, and the result was that none of them could make much money selling corn, and the corn rotted, then the farmers needed to learn to pick different crops. That was the "old deal".

That didn't work to end the Depression, so FDR wanted to try something different, by having the U.S. Federal government spend money to try and stimulate the economy. It included programs like Social Security. It involved hiring a lot of people to do public works programs, like building dams, or improving roadways, or creating facilities for public parks. There were farm subsidies, and bank holidays, and a lot of other things that were tried to boost the economy. Some of them worked really well, some worked OK but helped a lot of people, and some didn't work at all. Some things they tried wound up in court and were rules unconstitutional.


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

[User]
[The Boys]why exactly can't you just beat Translucent to death? you don't need to break his skin to just hit him until his innards break apart?

or just poison or suffocate him? they bring up the later but say it wouldn't work without explaining why?

[Assistant]
Translucent is resistant to blunt force trauma because his graphene skin distributes concussive force perfectly across his entire body; graphene has a crystalline structure that makes is very, very strong.

Poison or suffocation should work, though.


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

[User]
For planets with dozens of moons, do moons ever collide? And if so, what impact would that have on the planet?

In case of collision, do both moons cease to exist? Do their remains rain down on the planet like a meteroids, or are they pushed into outer space?

Losing our only moon would be catastrophic for life as we know it. But would it affect life on a planet when their moon counter drops from like 50 to 48?

[Assistant]
You're thinking from the wrong direction. You're pretending the moons just suddenly appeared and then wondering if their orbits intersect. The fact is that, as the solar system formed, the dust slowly coalesced into larger and larger objects with somewhat random orbits. Those objects collided over and over till the general spin of the solar system was all on a single plane in a single direction.

As they collided, they got bigger and bigger. Some formed planets, others formed moons, others asteroids. The bigger the object, the more likely it was to clear its orbit of other objects. The longer the age of the particular solar system, the more likely the objects have cleared their orbit. Moons are no exception.

The asteroid belt is an exception though. Jupiter is so big that it's gravitational forces keep breaking up anything that gets too big. This there are still lots of smaller asteroids in there. And they are so far apart from one another that they nearly never collide.

Our solar system is something like 4.5 billion years old. There has been tons of time for the moons of our solar system to clear their orbits. This means that, generally, they don't even get close to each other's orbits and so they don't collide, at least not anymore.


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

[User]
ELI5: What exactly is Chaos Theory? How does it apply to everyday life?

I have recently been delving into the world of complex mathematics. I came across chaos theory and dont full understand it. Can someone please explain it to me.

[Assistant]
Imagine dropping a bouncy ball on an uneven surface. It'll bounce around seemingly randomly. Except it's not random, it's following simple laws of physics, and if you could map out the surface it's bouncing on with enough accuracy you could predict exactly where it would bounce.

But because even a tiny differences in the first bounce would change where the next bounce lands, and then likely completely change the direction of the bounces after, it's basically impossible to predict even though it's following simple "rules".

There's what chaos theory is about, simple rules or simple systems that are totally unpredictable despite being simple.

There are lots of physical systems (eg. the weather) as well as purely mathematical systems (eg. fractals) that behave this way.


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

[User]
Why is Plasma so Rare/Non-Existent in Nature? (Plasma as in the State of Matter)

From what I've seen/heard about, in nature, elements being in a form of plasma is very rare if non-occurring, at least on Earth, and I was wondering why that is.

[Assistant] Stars are hot balls of plasma, and they contain the vast majority of matter in the Universe, so almost all matter is in the plasma state. If you're talking about on Earth, temperatures simply aren't high enough to allow electrons to escape the electromagnetic pull of protons. However, lightning bolts can briefly achieve this.


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

[User] [LOTR] Despite the existence of magic, why do they still fight using swords, axe and bows during war?

[Assistant]
Because magic doesn't exist for everyone. Each of those soldiers, orc and human alike, are all fighting by mundane means because mundane means is all they have available.

Wizards have magic. They're not even human.


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

[User] ELI5: If the universe is finite, does that mean that it has some kind of an edge? If yes, what happens if we "theoretically" cross that edge?

[Assistant]
The observable universe is finite, and the edge is the maximum distance we have seen. Its not  definitively possible that humanity could reach that eventually, but wed be observing more of the universe as we approached and moving our metaphorical edge further away.

Whether the whole of the universe is finite or not isnt known. We dont have concrete evidence of the shape of the universe, or if the universe even has a shape. It goes on and on past anything we can observe or measure, and is constantly expanding. Unless something changes on the literally universal level, we can never find the edge of the universe, or prove that it even exists.


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

[User] ELI5 How does one end up fainting due to locking their knees?

[Assistant]
Locking your knees has the effect of stopping your calf muscles from needing to move to keep you upright.  Youre supported by your bones instead, and kind of hang off your skeleton.

This doesnt seem very important, but your blood actually relies on your calf muscles to get back up to your heart.

Veins are the blood vessels that flow back towards your heart.   They are low pressure, unlike arteries which flow away from your heart and are high pressure.   Because of this, and because they go against gravity, veins have valves inside them to keep blood moving in the right direction.   Veins are found between your muscles, and every time you move the muscles squeeze the veins, which pushes the blood up through the valves towards the heart.

When you lock your knees, this stops happening,   Your heart keeps beating, and keeps pushing blood around - down towards your legs - but your legs will begin to form a pool of blood.   Less blood being returned to your heart means that there is less blood available to go to your brain.

Now, your brain *needs* blood constantly.   Like, way more than any other part of you.   When it doesnt have enough, it panics.   It has exactly one cure-all insta-fix for not getting enough blood, and that is to force you to instantly put your head level with or below your heart.   Its hard to get blood up against gravity, much much easier to do it on a level plain, and so its easier to restore blood flow to your brain if youre lying down.   So your brain makes you lie down, and makes it so that you have zero choice and zero time to delay - you faint.

That is how locking your knees leads to fainting.


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

[User] [DC] Could Deadshot land a shot on Darth Vader?

[Assistant]
A shot being blocked is not the same a missing a shot.

So deadshot probably could hit vader, but vader will simply block it with the force or his lightsaber or just tank it like he did on Bespin (assuming that wasn't the force).


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

[User]
If the near centre of a record rotates in 1 second (1cm/second) what would happen if the record was 1000's of metres wide?

If the record had a big enough diameter, and it was possible to actually turn it, why wouldn't it be going faster than light?

[Assistant]
This is a classic thought experiment in special relativity. The problem it's impossible for a record to be perfectly rigid, and therefore it's impossible to make a large enough record rotate uniformly.

This isn't an issue of just needing strong enough materials - it comes down to the nature of special relativity itself. When you spin an object, you do that by pushing or pulling on some parts of the object, using your hands or a turntable or whatever. That *push* is transmitted through the rest of the object, so that it all spins uniformly. However, this transmission isn't instant. It's transmitted from atom to atom, by atoms pushing and pulling each other to try to get nearby atoms to follow along with the motion. This is actually the same process that allows sound to be transmitted through material. In fact, the speed of this transmission does come out to be the speed of sound in the material. This is always much much slower than the speed of light.

So, if you had a record that was 100,000 km in diameter, and try to rotate it 1 rotation per second, the outer edge won't go faster than the speed of light. The speed of sound in metal is maybe 6 km/s, so by the time the rotation signal has been transmitted atom-to-atom from the inside to the outside, it's been over 4 hours, and the inner edge of the record has rotated tens of thousands of times. If the inner edge has rotated far more than the outer edge, you are tearing apart your record. It's not rotating uniformly - it's breaking.

For a disc to rotate uniformly, you need to transmit the torque instantly across the entire disc. "Instantly" is faster than light. So, if you assume something is rotating perfectly uniformly, you are accidentally assuming you can break the speed of light, and it's not surprising that assuming you can break the speed of light ends up proving you can break the speed of light!


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

[User] ELI5: How can merely opening an email be dangerous, if you don't download the attachments?

[Assistant]
Email at first was text only, now it can contain images, gifs, etc. This is because web technologies (HTML, CSS) spilled into email territory.
So, the email clients (Outlook, Thunderbird, etc...) now need the ability to render emails like a web browser but instead of reinventing the wheel and create a render engine, is easier to reuse an existing engine from a web browser to do so.
This open the door to vulnerabilities that can affect you with only looking at an email the same way a web page does, because now the email client has to interpret the code in the email to render it, and wherever code has to be interpreted there's always the danger of an exploit lurking.


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

[User] ELI5: why were zeppelins ever used in warzones in WW1? Weren't they really easy to shoot down, killing everyone on board?

[Assistant]
They were easy to shoot down *if* you could get a plane up there to do it, which was not easy back then.  Keep in mind, the whole "using planes as weapons" thing was still a new idea.  At the start of the war, planes were mostly used to spot enemy troupes and didn't bother attacking each other.  When they did start fighting, they started with just leaning out of the cockpit and firing pistols at each other.  Their range was very limited, their guns weren't accurate, and they had other things to worry about than the zeppelins.

Likewise, the zeppelins were mostly used for reconnaissance, usually too far and too high to effectively shoot at from the ground.  Airplanes going to attack the balloons had to contend with all the ground fire on the way, plus any planes protecting the balloons.  That said, yes they became pretty easy targets as airplane combat became more advanced.  But they were still useful, since they could fly high and stay there for a long time.  Airplanes simply did not have the range that zeppelins had, nor the carrying capacity for bombs.

They were especially useful at night, when they would be incredibly difficult to spot.  Remember, radar had not yet been developed, so the only way to know there were aircraft nearby was to hear them.  Zeppelins aren't completely silent, but they're definitely a lot quieter than airplanes.  And they would be high enough up that spotlights would have trouble spotting them, and guns on the ground would have even more trouble hitting them.


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

[User]
Is there a limit for the size of moons and planets?

Have we ever found a gas planet so big that one of it's moons is another gas "planet"? Is that theoretically possible?

[Assistant]
Even if a moon is the size of a planet, it's still a moon if it's orbiting a planet.

Ganymede, which is one of Jupiter's moons, is larger than Mercury and would be a planet if the sun, rather than a planet, were its primary.


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

[User]
[Godzilla] Could a team of elite snipers take Godzilla out via his eye?

It's a given that normal human weaponry doesn't do much to Godzilla but what about his eyes? Are they proportionally as tough as his body is?
If a team of elite snipers were to fire at his eyes, would it do anything?

[Assistant] When we talked with the Japanese soldier about their tactics against Godzilla, they noticed that even after taking multiple wounds from Planes, Tanks and even other monsters, Godzilla was able to heal all the damage done to him, so there is no reason not to believe that Godzilla wouldn't be able to heal his eye as well.


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

[User]
CMV: Media outlets sharing exit polls hurts democracy.

My opinion: Media outlets that share poll results, especially exit polls, during any stage of voting (i.e. early voting or on election night) hampers democracy.  Broadcasting exit poll results harms democracy by demoralizing those whose candidates or parties are polling behind, and by incentivizing laziness or inaction in those whose candidates or parties are polling ahead.

For both groups, the introduction of this impartial information can have a chilling effect on democracy, and the practice should be more heavily regulated.

[Assistant]
Conversely could it not also be motivating for people?  They see that the representative that they want is losing so they go vote and try to garner additional support?

Also should political attack ads be even more regulated then?  The point of those types of ads is not necessarily to convince people from one side of the aisle to switch but rather to encourage them not to vote for their opponent.  This is the same effect as what exit polling is doing but less objective.


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

[User]
[MCU] What happens if Bucky says his Winter Soldier trigger words to himself?

So the person who says these words is meant to control him, why cant he gain control of himself by just saying these words and preventing anyone from using him in future?

[Assistant]
In FATW we learn that >!his therapy in Wakanda worked and he no longer becomes the Winter Soldier upon hearing the trigger words!<

But previously to FATW, probably two things would have happened:

1) Nothing.

Hydra put in a failsafe in his mind so that he wouldn't be able to "activate himself" and act against their wishes. Maybe it was something like how trying to tickle yourself doesn't work.

2) He would have become the Winter Soldier.

However, without anyone to give him directions he just stands there like a robot awaiting instructions. After a few days he dozes off and when he wakes up he's snapped out if it.


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

[User] ELI5: What creates the mushroom cloud when an atomic bomb blows up?

[Assistant]
The air, dust, and ash caused by the explosion is *very* hot, which means it's way less dense than the cooler air around it. Like a hot air balloon, the hot mixture gets pushed up above that cooler surrounding air and rises. The atmosphere gets thinner as you go up, so even though it's cooler up there it's less dense. Eventually, the atmosphere will be less dense than the hot explosion mixture, which means the mixture can't rise anymore. It hits this "cap" of thin air and spreads out. Think of it like releasing a big bunch of balloons in a room, and when they hit the ceiling the ones on the bottom push the ones on top out of the way.

The ground is also still *really* hot from the explosion so as cool air rushes in to fill the space left by the hot air it gets heated by the ground and gets pushed up, too. As it does, it carries more ash and dust with it, creating the thin column of the "mushroom", squeezed inward by the cool air all around it.

That hot column of air keeps pushing up, forcing the hot gas mixture already up there out of the way. The mixture cools off, too, which makes it begin to sink back down a little. So hot column of stuff in the middle pushing up, which pushes the hot gasses out, and then down, to form the "cap" of the mushroom.

All explosions *kind* of do this, but they don't typically get hot enough to really show it. The layers of the atmosphere can be pretty distinct but they're still really deep, so it takes a big explosion to get the mixture of gasses hot enough to go all the way through the bottom layers and run into that really distinct line between two layers that makes the effect so pronounced.


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

[User]
ELI5: Why exactly are those gurgling sounds our stomachs make?

Why do stomachs make the sounds when we're hungry?  After we've eaten?
If you put your ear next to someone's stomach, there are countless, unique sounds that it makes...but none of them sound like fluids sloshing around like you'd hear in a water bottle.  So what exactly are we hearing?

[Assistant]
When you're hungry, it's called the migrating motor complex (MMC) - it's basically 'house-keeping' to move bits of roughage and fibre out of your intestines and to keep the whole system clean and tidy, without bits of old food sitting around. The sound you hear when your stomach growls tends to be from it vibrating while empty, the vibrations making the sound, and this is the start of the MMC which continues down to the end of your digestive tract.

When you have eaten, signals are sent to the brain to start normal peristalsis (intestinal movement) to move the food along, and the gases in your intestines plus the liquid-y food content (fluid having been added through pancreatic and stomach secretions) being squeezed through the intestines makes the sounds. It doesn't sound like sloshing because it's not uncontrolled movement, the food is literally being squeezed and the spurting of liquid and sudden movement of gas through a tight constriction causes the gurlging sounds.

I hope this is useful!


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

[User]
Postdoc question: are you being told how long of a lunch break and break to take?

Asking a Q for a friend. What are your breaks like? Do you have to follow a lab schedule imposed by the manager of the lab who is NOT your supervisor?

My friend was contracted to work from 9-5 daily and was told that there are rules to follow. Some examples:

 (1) lunch break 45 minutes - if late an email will arrive to let him know that break is 45 minutes not 50 minutes;

(2) he gets to take two breaks every day totalling 15 minutes a day between 9-5.

(3) Needs doctor's notes if he wants to take a break of more than 15 minutes.

(4) Cannot take naps (to clarify, he can use that 45 minute to take naps).

(5) If he arrives 10 minutes late, he has to work 10 minutes more by end of the day.

Also the person who does this basically looks at him all the time to track his movement and how many breaks he takes. It's an open cubicle and there are only undergraduate students around and another postdoc.

All this was not communicated before signing a contract - the only rule given was that he has to work 36-ish hours per week. Do you think he should talk to HR?

[Assistant]
Most postdocs have pretty minimal oversight -- check-ins once or twice a week (or sometimes even less) unless you're really actively collaborating on something.

What you're describing is absolutely fucking nuts, not normal.


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

[User]
Is capitalism possible without mass consumerism?

My understanding is that capitalism and the free market became the prominent societal model in the 18th/19th century during the industrial revolution, but it was not until the post-WWII era and the rise of the middle class, plastic and mass manufacturing that consumer society soared and eventually led to the destruction of the environment.

Can free market capitalism exist without mass consumerism?

One can argue that capitalism inexorably leads to mass production since change is motivated by increasing profits for shareholders, but is there a way to go back to standardized milk glass bottles delivered to your door and reused ad eternum instead of infinite choice enabled by single-use packaging?

[Assistant]
Sure. For the economy, it doesn't make any fundamental difference if people buy $3 per gallon cheap milk out of single use containers or half as much $6 milk from happy cows in environmentally friendly packaging. GDP would be the same.

I mean, one rather large factor is that greenhouse gas emissions are a negative externality. The entities that cause greenhouse gases aren't the ones that incur the cost of emitting them. And uncaptured negative externalities are generally less economically efficient than capturing them. That's also why a lot of economists have been advocating for carbon taxes for ages.

And sure, you could argue that capitalism might eventually lead to mass production, but how exactly is that bad? Instead of smaller producers whittling away at making their own glass bottles, you get huge factories serving entire regions mostly because that's more efficient and less resource intensive. That's honestly actually pretty important. Especially if you're concerned about the impact on the environment, not taking advantage of economies of scale seems like an incredibly dumb idea tbh.

But you have to keep in mind that consumers also have power. People like choice. Doesn't really matter at all what companies do, if people wouldn't take advantage of a wide selection of products, these products would just sit on shelves and would at least get cancelled and at worst the company goes bankrupt. Sure, in some sense companies can have a lot of power, but if nobody buys what you make, that's entirely moot.


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

[User] [Star Wars Prequels] How does slavery make any sense, given intelligent humanoid 'droids capable of working nearly continuously in baking desert conditions without a need for food, clothing, sleep, or housing, and are so cheap and plentiful that an eight-year-old made one from junkyard scrap?

[Assistant]
Its about status. On Tatooine, owning a slave implies a certain level of prosperity, and to bet one is one of the highest non-monetary bets you can make. It really isnt a matter of practicality at this point. Its all about power, or the illusion of it at least. Also, slaves are versatile. Getting a droid capable of multiple useful roles is surprisingly difficult, owing to programming and construction. An organic can adapt with little trouble.

Its still horrible, though, and altogether inefficient.


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

[User] [Diablo3]The Monk refers to his gods a number of times and the Crusader believes in the Zakarum. How do both reconcile the fact they go to Heaven by the end of their game, see angels die and that their gods are not there?

[Assistant]
Both the Zakarum and Sahptev (the Monk's) faiths acknowledge the existence of both Heaven and the Angels as part of their belief systems.

It's unknown how the Sahptev faith views Heaven, but it doesn't seem to be considered as an afterlife. Most likely it is just considered to be the home of the Angiris Council, who themselves are considered gods but, at the same time, are not viewed to be part of the Sahptev pantheon. The actual pantheon is said to be part of the world and not in Heaven, existing as personifications of objects and concepts. The Monk, then, probably wouldn't have had any need to reconcile anything after their trip to Heaven since nothing they see explicitly goes against their faith.

Zakarum says that Heaven is the resting place for those who were virtuous in life. While there doesn't seem to be any evidence for that (Deckard Cain believes that human souls go to some unknown location instead), the lack of any human souls could be easily rationalised as them having been shepherded away to safety by the angels, which would keep them far away from any of the areas the Crusader visited.

Seeing angels die, while likely upsetting, isn't faith shattering. Plenty of religions allow for their gods or other divine figures to be killed or destroyed, so it's not as alien a concept as you might think.


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

[User]
CMV: Sex work should be discouraged.

When I met my girlfriend she was really close to doing it. She had deep issues with self esteem, she was approaching her mid 20's with no discernible direction in her life, she was getting frustrated with her job and she had a close friend who was already doing it and making good money. This is a perfect storm for a girl to get into sex work. But I think it would have been a decision which irreparably damaged her if that was the path she chose.

I don't hold anything against sex workers. I don't think they have less inherent worth as a human being.

But I do think that you should discourage anyone you know and care about from being involved in it, and I don't think there are many if any good reasons to do it.

I believe (from my limited experience) that the majority of those who get into sex work have issues with mental health and especially self worth. I believe that a majority of those who do it are vulnerable people who become even more vulnerable through sex work. I believe that when you put a price on yourself like that and let yourself be treated like an object it would be extremely hard for it to not have a negative impact on your self esteem.

Mostly I believe that there are so many things that a human being can be and achieve in our society and that it's a deadend job which obviously doesn't offer much upward mobility. It's a quick way to make good money, and I think most girls who do it probably regret it, and the ones who don't would if they weren't so fucked up by the experience.

I would like to believe differently though.

[Assistant]
Do you have evidence for your claim that "most" people who get into sex work have self esteem issues?

And, do you think the problem is sex work as a concept, or do you think it perhaps has more to do with the structures, stigmas, and potential dangers of sex work in its current form?

Furthermore, sex work is already extraordinarily discouraged. Prostitution is literally illegal in the US, and sex workers pretty often say the worst thing about their job is the stigma - a very intense amalgamation of all the discouragement expressed toward sex work.


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

[User]
ELI5: How is it that losing 1kg of bodyweight reduces the load on your knees by 4kgs?

Where is all that extra weight coming from?

[Assistant] When you step on some weighing scales the pointer goes past your weight and then back down doesn't it. But the pointer can only show how much force is being pushed down on the scales. So when we step on something the force we land with must be higher than our weight.


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

[User] Eli5: Why computers use separate jack for mic and headphones while mobiles use the same jack for input and output.?

[Assistant]
Typically those combined jacks have the same number of contacts as the separate jacks put together. They are just all together.

You can buy adapters that split these up or merge them to  connect devices meant for one type to the jack meant for the other.

Small devices tend to use combined jack because it saves space and because people are less likely to use separate peripherals for audio in and out on something small like a phone or tablet.

Computer use separate jack because you are more likely to have separate headphones and microphones on your desk and because they have room to spare.


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

[User] ELI5: Why do some plastics discolor and turn white when they are stressed/bent?

[Assistant]
For plastic it actually creates micro fractures in the structure in a process called work hardening. The white is basically tiny air voids retracting light differently. There are no chemical changes to the structure it's just mechanically breaking down. If you were to measure the density of it at that point you would find it has decreased.

It's similar to how you can beat egg whites into a foam.


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

[User]
[Die Hard] When John and Hans meet incidentally, John sneaks a look at the employee list and then challenges Hans with "what's your name?" Hans tells him it's "Bill Clay", without having seen the list himself. Did he have some of the male employees names memorized from planning the heist?

I know this isn't a sci-fi question, but I can't seem to find a general "ask movies" subreddit, so I'm submitting it here.

[Assistant]
meta: Ask Sci-Fi isn't really just for science fiction. It's for in-universe answers (like Watsonian-style comments rather than Doylist). There's a bunch of FAQs on the sidebar about the difference in perspectives, but basically it means using resources that would be available to the characters rather than statements from the creators.

To answer your question... there's two possibilities.

First we know that Hans had to learn the names of at least some of the employees, because he needed to know who had the codes for the vault or were otherwise involved in security.

The other option is that Gruber was in the room before McClane showed up. A quick glance at the board is all it would have taken, it was listed as "W. Clay" which wouldn't really take any sort of time to read. Gruber might have just spotted it, and needed the name before he had time to forget it.


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

[User] [LotR] Destroying the Ring destroyed Sauron's power without killing his spirit. Would it have theoretically been possible to kill Sauron's spirit without destroying his power?

[Assistant]
No. In Tolkien's legendarium, a being's soul or spirit is eternal, or at least unkillable. Death is the act of separating body and soul, but in the cases of Elves and Ainur, the soul remains in existence and bound to Arda. In the case of Men, the soul departs Arda completely to an unknown fate.

The only way to achieve a final defeat of Sauron was to strip him of his power as they actually did, or to imprison him or cast him out of the world as they did with Morgoth.

All that said, if you're asking if they could have defeated Sauron and kept the Ring, then yes, in theory they could have done so. A powerful being such as Gandalf would have had to wrest control of the Ring from Sauron and align it solely to his own will. The affect on Sauron would have been the same as it's destruction though - he'd lose his power and be reduced to an impotent spirit.


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

[User]
I believe that grading on a curve is stupid. CMV

I understand curving when the grade distribution doesn't reflect what it should, e.g. one test was more difficult than expected.  I'm talking about intentionally making a class difficult and assigning low grades under the assumption it will be curved to reach a normal distribution.

I understand that some do it emphasize that you don't know enough to be able to claim mastery of the subject, but the idea is that the grade should reflect mastery of the assignment at the level of the class.

If the majority of the class scores a 60 percent average on an exam, and that is considered normal, then doesn't that indicate that the issue lies with the lecturer and not the student?

EDIT:  To make it more clear what I was trying to get at, why do professors choose to add curves in only at the end of the semester, as opposed to throughout?  Even if it lets your brightest students shine, it disadvantages the rest of the class in not knowing where their grade stands until the end of the semester when it is too late to do anything about it.

[Assistant]
>If the majority of the class scores a 60 percent average on an exam, and that is considered normal, then doesn't that indicate that the issue lies with the lecturer and not the student?

Why need there be an issue?  What's wrong with a test where the average score is a 30%, so long as it appropriately distinguishes the good students from the bad?

In general, an easier test helps select for students who are careful and meticulous and don't make mistakes; a harder test helps select for students who really understand the material.  So making a hard test is not a bad thing - the professor simply needs to make sure she is giving out appropriate numbers of As and Bs despite hard tests.


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

[User] ELI5: When TV shows use really good music from really unknown groups, how did they find it?

[Assistant]
Most TV shows have someone on staff called the Music Supervisor. It is their job to acquire the songs you hear on a show, negotiate their rights, etc. Sometimes there's a specific song the show wants for a scene, something real famous, but most of the time the producers/writers don't have the time to nitpick through and pick all their music, so they say "we want an uptempo song here" and the Music Supervisor goes to work.

The Music Supervisor is generally someone in the know about indie music (a lot of the shows that are produced in LA use the DJs from the highly influential KCRW radio station), whose job it is to find the hot new bands before they're hot. If a show has a certain tone or feel to it (eg Veronica Mars and its neo noir ambient soundtrack), the Music Supervisor will quickly get a handle on the groups that fit the show, and as the show builds traction they might even begin to get a ton of demo CD's from the various labels who want to increase their band's visibility by putting it on the hot new show.

Record labels know who the Music Supervisors on the tastemaking shows are, they develop these relationships as the shows license more music from them, so if a label has a new act they want to get out there they'll reach out pre-emptively and say "hey, we got this great new act, here's their album, wanna put it on your show?"

The other thing that might happen sometimes (although this seems to happen less and less these days) is that record labels will attach unknown acts to known ones. You want that Radiohead song that you love? That'll be 50,000 dollars, PLUS you have to use these 5 other songs from some of our up and coming artists in your show as well.

Source: worked in the sound dept of a major TV studio for 4 years, saw this kind of stuff on the regular.


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

[User] ELI5: Why is China able to build entire cities in the time it takes most western nations to build one skyscraper?

[Assistant]
A big part of this is what what the Party says, goes. There's no "due process", which is time consuming.

You saw this when they built the Three Gorges Dam, for instance. In order to make room for the rising water behind the dam, 1.3 *million* people had to be displaced. If each of those people could file a lawsuit against the government, they'd still be in court when the sun went out. Instead, the government pretty much said "Here's a little money for your land, and if you cooperate, we'll help you move, but the decision is already made - take it or leave it."

This also goes for things like environmental impact statements (again, that dam is a big example). Any large project in most places, such as the US, has a whole process leading up to actually breaking ground, including environmental impact statements, plans for various contingencies/disasters, evacuation plans, etc. If the Chinese government needs these things done quickly, they can simply throw as many people as they need at the project, without worrying about the budget, the way a private corporation might. They can also grant waivers, so some of that stuff might not need to be done at all, or might be postponed until later.

Short version: The upside of not being a Democracy is that you can just order people to get things done.


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

[User]
ELI5: What gives different people's houses their unique scent?

I think I could be blindfolded and know whose house it is just from smell, and objects from there also carry the scent. Is it just perfumes and air freshener or something else?

[Assistant] It's usually based upon what kind of pets you have, what kind of laundry detergent one is using, what you eat/cook. And a ton of other factors like how well your house is kept/having no moldy foods, what temperature it is, etc...


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

[User]
Why is a land value tax considered the "ideal" tax by economists?

Wikipedia says it is considered a perfect tax. I suppose because it encourages the usage of land, is tied to a scarce and limited resource, etc.

But how does it fall out in practice? Does it make for good policy? Why aren't the costs be passed onto tenants (which I have read elsewhere)?

[Assistant]
Taxes on *unimproved* land value are "perfect" in some sense because they are lump sum taxes, and they do not distort decisions on the margin. The reason is that a landowner cannot change the unimproved value of their land.

In contrast, the downside of things like income or sales taxation is that they distort work and purchase decisions away from their optimal values (if they were optimal to start with). Income taxation, for example, disincentivizes work.


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

[User]
Do residents of poor neighborhoods want outsiders to stay out?

When I move to or visit a new city, I usually try to visit some of the poorer neighborhoods. I have a variety of reasons for this, but I've long felt this was part of getting a true idea of what a place is like. San Francisco would be a different place without the Tenderloin, etc. But, on at least a couple of occasions I have been told that I shouldn't do this, because the people living there don't want me there. Is there any truth to this? Doesn't social and economic isolation just perpetuate poverty? I don't know where else to post to get an answer to this.

[Assistant] Lots of neighborhood studies talk about how neighborhoods keep outsiders out on general purpose, suspicious that they could be anything from rivals looking to steal shit, to authorities looking to bust people. Check out Suttles *Social Order of the Slum* or Eli Anderson's *Streetwise* for more on the topic.


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

[User] Eve Online has a PhD economist on staff. What's the most interesting economic insight to come from studying Eve's economy?

[Assistant]
I dont know, but you can check.

If you go to scholar.google.com there are some studies that pop up when searching economics eve online

I left this in your asksocialscience post but it was removed for not having a citation.


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

[User]
ELI5: Why are planes not getting faster?

Technology advances at an amazing pace in general. How is travel, specifically air travel, not getting faster that where it was decades ago?

[Assistant]
Passenger aircraft fly around 85% the speed of sound.

To go much faster you have to break the sound barrier, ramming through the air faster than it can get out of the way.  This fundamentally changes the aerodynamic behavior of the entire system, demanding a much different aircraft design - and much more fuel.

We know how to do it, and the Concorde did for a while, but its simply too expensive to run specialized supersonic aircraft for mass transit.


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

[User] ELI5: When shot/wounded, why are you so thirsty for water?

[Assistant]
If you have a *significant* amount of blood-loss you can experience feelings of dehydration.

All the cells in your body have lots of water stored in them. When you bleed, you're losing blood, but also the right amount of fluid in your arteries/veins to keep everything flowing. (Think of a garden hose that is just trickling out water, because you don't have enough water coming from the tap)

What you body can do, to make up for the blood you're losing, is pull the water that's stored in your cells into your bloodstream. Less water in your cells means dehydration.

Although, losing that much blood, drinking water is probably not on your mind.


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

[User]
Why are solar panels in fields all angled a certain way, as opposed to pointing towards the sun?

edit: towards the sky, not the sun.

[Assistant] Tracking panels are much more expensive and require more maintenance. It's fine for satellites or space probes, but when you need to outfit entire fields with that, it comes at a price. So you use a static panel that is oriented in a way that maximizes daily output in current location.


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

[User]
ELI5: Why does Horseradish only burn your nose?

Same goes for mustard I suppose. Why does it not affect my mouth as much, but makes me feel like I'm breathing fire out my nose?

[Assistant]
The heat in horseradish comes from a highly reactive chemical ( isothiocyanate ). The chemical stays pretty stable as long as it isn't introduced to oxygen. When you chew on horseradish, you crush the plant (saliva also aids in breaking it down) and release this chemical which immediately reacts with the oxygen in the air and THAT is the moment it becomes hot. Now you breath even a little and its in your sinuses and burning ensues. If you breath a lot its in your lungs and you'll get a different crazy ass sensation when that happens.

Mustard is similar, but different. It's water that kicks off the reaction there, but the chemical shares a commonality with mustard (the are both  phenolic  compounds) but that's probably far enough for ELI5.

Oh, fun fact, if you put vinegar in Horseradish very early after you grate or crush it, it will stabilize the reaction and keep it more mild.


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

[User]
ELI5: How is a Mafia boss chosen?

Is it the son that takes over? What if he has no interest in being the boss?

[Assistant]
Having a "claim" to the position (being a close family relative) helps, but it's really about who has the most support in the organization (and outside of it).

If you're just some low level guy and the boss dies, you wouldn't be stupid enough to make a play for the top (you would die).

If you're second in command and the boss dies, you'll be expected to either take command yourself or throw your weight behind a new boss (like the old boss's son or something).

So, people without a chance are incentivized to stay out of the way, hopefully leaving just one person (or group of people with a figurehead leader). Things get dicier if there's more than one person with a halfway decent claim to the throne. If that's the case, things get violent until it's clear who will win.


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

[User]
ELI5: how do computer parts work?

I am relatively into gaming, have my own custom PC, and have been around digital tech since I was a child. I can relatively easily operate a range of systems, and have little trouble working new systems out. What I can't for the life of me understand is how different parts communicate with one another, or how you even translate Pc parts to understand a language at all. I am aware of the rough idea of it being 1s and 0s, but how on earth do these mean anything to a computer that has no real understanding of what a 1 or a 0 is?

Edit: I now have far more questions than I thought was even possible. Ill stick to my dad job and leave the computers just for playing games. Thanks everyone who tried!

[Assistant]
How binary works:

It's base-2 arithmetic. It works like base-10, which you are used to, but with only 2 numbers. So in base-10, you count from 0 to 9 and then append a 0 and count from 10 to 19, and so on. In base-2, you count 0 1, then append a zero and count again. You just have to append zeroes faster. Here's a little conversion table, decimal to binary:

0 = 0

1 = 1

2 = 10

3 = 11

4 = 100

5 = 101

6 = 110

7 = 111

8 = 1000

9 = 1001

10 = 1010

And so on. In this way you need only two digits to count as high as you want. Each number representing a 0 or a 1 is called a bit. It comes from Binary digIT. One byte contains 8 bits, and it can represent any integer from 0 to 255, like this:

0 = 00000000

...

255 = 11111111

Now it's a matter of assigning numbers to everything else. For instance, you could say that a "1" represents an "A" and a "2" represents a "B" and so on. You continue with something like this and you assign numbers to all the letters, all the numbers, lower and upper case, emojis, and what have you. You also assign numbers as addresses to each pixel on a screen, and you assign numbers to various colors.

Computers are really good at repetitive calculation, so by representing everything as numbers we can easily store, retrieve, and operate on anything.

Languages, as in programming languages, are not that much different; at the most basic, there are very simple languages that use numbers to represent simple instructions. For instance, a "+" could be assigned a number, and so could a "-" and a "x" and so on. There are mathematical operations that you learn further along, perhaps in high school or in college, that have names like AND and OR and NOT; there are others, a bit more advanced, that have names like IF and ELSE.

Put it all together and you can write programs that can operate on all those symbols according to rules that you define.

The PC parts don't really translate things between concepts and 0 and 1. They operate mathematically on bits, and that is all. It is the collection of those bits, and the way we choose to organize them and display them, that has meaning. This paragraph makes sense to you if you speak English; to the computer it is just a series of numbers, with no particular meaning. There is a lot of software between you and me that makes it appear to you as letters on a screen; and you are the one doing the interpretation.

How different parts communicate with each others is easy: they transmit signals to each other using wires. It is a bit more complex than that, and the wires are really tiny, but in the end as part of running your game the CPU will send signals through wires through wires to the memory, which will reply by sending memory contents; it will operate on some of those contents and send it as signals on wires to the GPU, wich will turn those into instructions to light pixels in a certain order and color and so on.


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

[User] [MCU] What's the state of Extremis after Iron Man 3? How much does Stark know about it?

[Assistant] Don't know if Stark is supposed to be still fiddling with it now, but Extremis made it into Agents of SHIELD as an ingredient to a knock off super-soldier serum developed by HYDRA to create an army of remote-controlled super-soldiers and Deathlok.


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

[User]
I've come up with a way to "prove" (Please note the quotation marks) that 1/0 = Aleph Null. Can anyone explain where the error(s) is?

First of all, the sum of a convergent infinite series is a/(1-x) with a being the first term in the series and x being the multiplier that terms successively multiply by, e.g. a + a*x^1 + a*x^2 + ...

So, if we do 1+1+1+1+..., a is 1 and so is x, therefore we get 1/1-1, which is 1/0, therefore 1+1+1+1+... = 1/0

Since 1/0 is obviously undefined, this has to be wrong, but I don't see the problem. Can anyone please point out the error for me?

Thanks if you do.

[Assistant]
First, the sum formula you mention (a / (1 - x) ) only applies to convergent *geometric* infinite series. There are many other infinite series, convergent or otherwise, that are not geometric. But that's a sidenote.

As you state, perhaps somewhat inadvertently, the sum formula applies to a convergent series. A geometric series only converges if the absolute value of the multiplier (x) is less than 1. (So: |x| < 1).

In your example, this is not the case. So the series does not converge and the formula for the sum can't be applied.


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

[User]
If non cognitivism is the rejection of truth value in moral statements, why not abandon morals altogether?

I can't understand why non cognitivists would even talk about morals existing, and what constitutes morality if to them all morals lack truth value or not. As in, what's the point of talking about morals when there's no truth to be discovered in moral statements at all?

[Assistant] What's the point of saying ouch when you stub your toe? Or clapping at the end of a performance of a play? Or crying when you're sad, or laughing when you're happy? Or cheering at a sports game? Or saying yuck when you eat something yucky?


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

[User]
[general] Would wear and tear of a loop-travelling object cause its casual-loop to break?

Eg. Consider an empty space, then a ball appeared right when time starts ticking. The ball stayed in the space for 10 seconds, then vanished back to 10 seconds ago to exist when there was nothing 10 seconds ago, causing the ball to exist like the beginning.

Since the ball would age (really slowly) every 10-second duration while it lasted, would the paradox break if the ball breaks due to wear and tear after a thousand years or so (like, billions of seconds)?

[Assistant]
The way you've set that up, yea, the loop would eventually break.  And it's not really a causal loop for that reason.  It's more just a ball being repeatedly sent back in time.
A causal loop generally has an older version of a thing acting on a younger version of itself in order to perpetuate the loop.  In this way, aging is not a factor because the loop always starts with a young version of the object.


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

[User]
My daughter asked why are there bubbles in soda water.  I told her it's elves' farts.

Help me give her a scientific answer, it seems very hard to explain.

[Assistant]
At the factory they pump gas called carbon dioxide into the soda water. They use a very strong pump that actually forces the gas to dissolve into the water, like when you disolve sugar in water. It squeezes the gas into the soda an it is trapped in there  for as long as the cap is on.

Taking the cap off releases the pressure and the gas can escape from the liquid again - it forms bubbles.


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

[User] [TheLegendOfKorra] has their ever been a "bad" avatar?

[Assistant] Having Raava and all of the past Avatars whispering in your ear (either physically or metaphorically) for your whole life is a powerful influence.  All Avatars known (and likely all Avatars) have had a massive boner for balance, and have just generally been helpful people.