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

[User] [Discworld] How did Rincewind, a person with almost no magical ability, get into Unseen University?

[Assistant]
He had the potential to use magic when he was a kid. That allowed him to study until he became a full fledged wizard or flunked out.

He ended up getting that one spell stuck in his head. That spell was important enough to allow the faculty to let Rincewind stick around.

After the spell leaves, the next time Rincewind is in UU he has already saved the world twice, so he is pretty much an honorary wizard.

Plus, bad things always happen to him. The other wizards realize that Rincewind is like a lightning rod. As long as Rincewind is around to take all the bad luck, everyone else is safe.


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

[User]
Why didn't the Jedi investigate Anakin's conception?

He was a pretty big deal and had a miraculous conception of sorts as far as the Jedi knew. Seems worthy of investigation.

[Assistant]
What's to investigate? His father was the force. They knew it could happen, they knew how it can happen, and they knew it would happen. Using the force, Qui Gon knew that Shmi wasn't lying, and using the same techniques, the Jedi council knew Qui Gon wasn't telling porkies.

Perhaps the only question remaining is: "why Shmi?" ... but this line of reasoning is anti Jedi thought. A well conditioned Jedi focuses on the moment at hand, and the moments to come. The past is unchangeable, so there is no point in dwelling on it. Residing on things past can only lead to malcontent... which will lead to the dark side.

I think the only way the Jedi would investigate this further, is if immaculate force babies started popping up everywhere. This would be unexpected, and have a large impact on the future AND the present.

As it stood, there was one force baby, he was expected, and he was under close observation by the Jedi council. Things done be covered.


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

[User] ELI5 If skin is constantly renewing itself, why do blemishes remain?

[Assistant] The outer layers of the skin are formed by the cast-off remnants of the deeper layers. Blemishes exist in the underlying layers of the skin, where the cells are dividing to replace lost ones, and those get expressed on the outer layers as the cells surface and slough off.


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

[User]
How long is the LHC at CERN on for at a time? How long does it take before a test will be done?

Does it take a long time to actually charge up? Somebody told me itll take months before anything actually happens after they turn it on today, but I wanted to ask here if thats how it works.

[Assistant]
The ideal long-term running plan has ~10 hours of non-stop collisions followed by 2-3 hours of dumping the remaining particles, ramping down the magnets, preparing for a new fill, filling in particles, accelerating/ramping up magnets, and preparing the beams for collisions.

You can't fill in more protons once they have been accelerated, so over time the number of protons and therefore the collision rate decreases. The 10 hour number is the approximate point where it's better to accept the 2-3 hours downtime in exchange for going back to the initial high collision rate again. That gives us about two fills per day and collisions ~70-80% of the time.

The LHC has tons of components that all can have some issues, so realistically the time between collisions is often a bit longer, and sometimes these problems can stop collisions, so in practice the fraction of time with collisions is lower - something like 30-50%. That also means fills are often kept for longer than 10 hours if possible, because we know the average time to the next collisions is higher than the optimum.

Looking at a longer time frame: Every winter there is a shutdown for maintenance, smaller upgrades and so on. After that the machine parameters need to be tuned again. That means the accelerator starts with very low beam intensities to be on the safe side. After a long shutdown (e.g. like this year) it's even worse because many components are new and the operators have to make everything work together. Establishing collisions, stable beam parameters, and going to higher beam intensities takes a few months, followed by a few months focused on data-taking (with some time spent on pushing towards even higher collision rates). We already had some initial collisions, but only at a low rate and with parts of the detectors still switched off. The plan for today is collisions with all detectors fully switched on, i.e. the start of physics data-taking. The collision rate will still be very low.


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

[User] ELI5: Why do digital movies have such a hard time blending black and white, like when a person is in a dark room with a lantern? There are obvious rings as the colors fade into black.

[Assistant]
That's called "banding", and it's due to compression. One of the steps of compression is to increase the length of sequences of the same color. This is done by combining similar colors into one. The combined results will have less granularity, and thus the distinct steps.

Banding is a reasonable trade off to have a small file size. If videos aren't lossfully compressed, even a small video would be gigantic. With that said, the result can be improved drastically by doing frame-level adjustments on which color ranges to compress and avoiding ranges where a gradient is present. But that's operationally costly.


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

[User]
Why does blue seem to be the hardest color to achieve for so many things, such as LEDs, fireworks, and paints or dyes?

What makes blue special? Also what category would this be?

[Assistant] Not an answer but blue is the shortest wavelength and therefore the highest energy of the visible spectrum. And higher energy is harder all around to deal with. For example, 7,000 kelvin light bulbs emit a lot of blue spectrum and many people find them to be burning and fatiguing of their vision. Another example is radio engineering, where higher frequencies are orders of magnitude more difficult to design and have increasingly erratic behavior. So it is built in to the wavelength/frequency of the light wave and the amount of energy required to generate it.


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

[User] [ELI5] Why you can't drink water couple hours before a surgery?

[Assistant] They dont want you to aspirate. A lot of things that happen when they first put you under can potentially make you vomit and if that goes into your lungs (aspirating) it can block your airway or cause an infection. Having your stomach empty means that risk is much lower.


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

[User]
ELI5: Why can some insects survive high radiation levels they wouldn't encounter on Earth and others don't?

For instance take the clichd cockroach. They can survive substantially higher levels of radiation such as that from a nuclear weapon. Surely in nature they would never encounter such high levels of  radiation, outwith some stellar events. Furthermore why do only certain species have such a great tolerance to radiation whilst others do not.

It seems like genetics are coding for an unnecessary and unlikely exposure to radiation. Thanks!

[Assistant]
They do not have specific adaptations for surviving radiation, but they are pretty tough little bugs that can survive injuries, starvation, etc. Insect biology just handles radiation damage better than mammals and things, mainly because they're much simpler than vertebrates.

There are arthropods that can survive the vacuum of space, not because they need to live in space bot because they evolved to survive *dessication* (drying out). Tardigrades are the instant ramen of the arthropod world.


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

[User]
What is the importance of the prime numbers?

I've often wondered what the importance of prime numbers are, since they seem to be stressed in mathematics. I've asked this question many times (this is the first time I've asked reddit), and I either get my question "answered" with a question, or a smarmy answer.

Can someone please explain to me the applications and potential benefits from, say, one day finding *the* prime number formula? I do know that there are applications for this in cryptology, but outside of this, I'm not sure what the implications are or what the importance is. Thanks in advance for any help! This question has always nagged at me.

[Assistant] Just to give an illustrative example, one of the most important properties of the natural numbers is the Fundamental Theorem of Arithmetic, which says that every natural number has a unique prime factorization. This fact was crucial to Gdel's proof of the Incompleteness Theorems, which is widely considered to be one of the deepest results about mathematics that has ever been proved. Gdel's Incompleteness Theorems state that any axiomatic formal system that is powerful enough to capture arithmetic will always be either incomplete (in the sense of not being able to prove everything that's true) or inconsistent (in the sense that one can prove a contradiction), and that no such system can prove its own consistency. Gdel's famous proof involves attaching a number to each symbol in the formal language, and then storing these numbers as the exponents on an increasing sequence of prime numbers. This "arithmetization" assigns a number to each statement in the formal system, and because of the Fundamental Theorem of Arithmetic such an assignment is guaranteed to be unique. Given a number, we can write the statement that it represents, and given a statement, we can calculate the number that gets assigned to it. Arithmetization gives the formal system a *recursive vocabulary*, meaning that the system can say things about itself. For example, Gdel proved that there is a statement which says of itself "This statement is not provable." If the statement is false, then the system is inconsistent, and if the statement is true, then the system is incomplete. Gdel proved that this is an inherent property of such systems, and that there is no way of getting around incompleteness (such as by adding new axioms). This groundbreaking and frankly shocking result of metamathematics depends entirely on the properties of prime numbers.


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

[User] [James Bond] Besides recovering from his injuries does 007 receive any downtime between his assignments or does he start another one right after the last?

[Assistant]
Think of 007 more as a pointed instrument meant to finish a job or to  express Her Majesty's will in the most express physical terms.

007 is only activated for missions that require his particular skill set, namely his license to kill and general stealth and mayhem causing. It is one reason he always identifies himself as James Bond and never tries to hide his identity too much. If James Bond appears on your doorstep, it is already too late for you to change Her Majesty's government's mind. You are slated to die and your operation is meant to be completely dismantled.


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

[User]
[Discworld] What makes the River Ankh so polluted?

It is said that the river is so polluted running through Ankh-Morpork that you can walk across it, and that it's the only river where you can draw a chalk outline.

However, in our world, such pollution has only come as the result of industrialization, where factories, sewage systems and large scale agricultural runoff create situations like the Ganges or the Cuyahoga. What's causing all the upstream pollution along the Ankh?

[Assistant]
The entire Sto Plains drains into the Ankh. While that's mostly farmland and small cities, there are still some areas there affected by the Mage Wars.

When rain falls on Sto Helit, water flows into the Ankh. When rain falls on the Forest of Skund, you get the magical equivalent of toxic waste. Sometimes it's more or less water, sometimes it's ectoplasmic slime, sometimes it's seven thousand sapient jellyfish, all named Harold.


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

[User]
[WH40K] Has the Imperium ever performed exterminatus on an Eldar Craftworld?

I mean if their goal is to purge the Xenos, why not find the Craftworlds and obliterate them?

[Assistant]
They have, but the consequences of doing so aren't worth it.

There have been 3 known attacks on Craftworlds by the Imperium. One resulted in the loss of an entire sector fleet, and was unsuccessful. The second, while successful, caused extreme loses and the counter attack wiped out multiple chapters. The third, had it not withdrawn, would have caused a retaliatory strike that wiped out hundreds of worlds.

Sometimes it's better to swat the occasional hornet than to disturb the nest.


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

[User] ELI5 why are wooden barrels "barrel-shaped" (i.e., wider across the middle than at the top and bottom) rather than cylindrical? Wouldn't cylindrical containers be easier to build, store, and transport?

[Assistant]
Barrels that are full are VERY heavy. That's a lot of liquid.  So you want things that are easier to handle, not just move. And barrels have that bulge that makes they way better for this than a cylinder that's shaped like the cardboard in a toilet paper roll.

First, a barrel that has a rounded-outward middle is actually much easier to roll due to one point hitting the ground rather than the whole width of the cylinder. There's a lot less friction and a lot more control to do stuff like turn direction easily and quickly, something that's harder to do with a true cylinder shape.

And then it's a lot easier to push upright when it's lying down. You can rock it to start it tilting up, and then push a little more once it's rocking... and up it goes. A cylinder is a LOT tougher - you have to pretty much lift it instead.

But wait! There's more! They're easier to build really strongly too!

Barrels are made by steaming arranged pieces of slightly-angle-cut wood under pressure, bending them into a curve at both ends, and then jamming a couple iron hoops over their outsides from top and bottom, squeezing both towards the middle until that bulge is really squeezed tight. The curve in the wood provides the extra outward force, pressing hard against that iron hoop, to keep the whole thing together and snug.

Well, that hoop's a lot easier than something adjustable that could fit over a perfect cylinder and then be tightened. You don't get that barrel-shape's magical ability to create more tension by just sliding the hoops on both ends toward the centre to create more pressure - you have to somehow tighten the iron hoop you're putting on instead on a cylinder.... and that would be a lot harder to do without slipping. You'd need something like a ratchet or a knotted and welded cable, instead of a simple and easy-to-make hoop. So guess which is cheaper?

Easier to move a lot of liquid, easier to stand it up after moving it, and easier and cheaper to construct. Lots to love about ye old-timer barrels compared those sucky cylinders!


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

[User]
During its creation, how exactly did the Earth cool down?

As far as I've known the heat energy from the creation of Earth has to go somewhere for Earth itself to cooldown. Where did all that heat go?

[Assistant]
Radiation going into space.

Every object will emit electromagnetic radiation, with the spectrum and intensity depending on the temperature of the object. This is called thermal radiation. On the other hand, in the solar system objects also receive radiation from the sun. Ultimately, an equillibrium will be reached where the amount radiated out is equal (in terms of total energy) to the amount of solar radiation absorbed.

When the Earth was young and hot, it radiated far more than it absorbed from the sun, causing a net loss of heat. This caused the temperature to drop, lowering the amount of radiation emited, etc... until an equillibrium was reached.


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

[User]
ELI5: The "It's my body" argument for pro-choice.

[DISCLAIMER THIS US NOT AN ABORTION DEBATE THIS IS INFORMATIVE PURPOSES ONLY]

Why is it okay for a women to say "It's my body" to justify an abortion? Because the fetus living inside her is NOT her body, rather it's just dependent on her body to survive. Like a parasite it's a separate organism.

[Assistant] In the same way that you're not legally required to give a kidney to someone to save their life. In the US, we generally have the right to choose what medical procedures we will have, even if someone else's life depends on us.


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

[User] ELI5: How do screens smoothly scale resolutions that aren't multiples of each other? E.g. playing 1080p or 720p video on a 900p screen, or reducing my phone's resolution from 1440p to 1080p?

[Assistant] There are complex algorithms that will combine pixels with their neighbors in certain ways. If you have a higher resolution screen being scaled down such that a pixel should be 70% one color and 30% a different color, the calculation would yield a combined color of the appropriate proportions.


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

[User] [Naruto] Do evil ninja have to develop special creepy techniques, or do ninja who naturally develop creepy techniques just embrace being evil?

[Assistant]
It goes both ways. Take for instance the 'creepy' snake thing that Oricmaru does. He used to be good kind of sort of, but he's always had this ability. In that same vein he's a known creator and studier of forbidden Jutsu.

Plus really those who create a forbidden jutsu, just don't do it, or choose to do it and be labeled evil.


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

[User]
Training in asking Socratic questions.

How can I practice the skill of asking Socratic questions? How do I keep myself from bullshitting as I practice? I get the feeling that working with other people in the flesh is 100% required for both of these, and that the Internet is a waste of time for anything (curses!), is this true?

[Assistant]
If you are referring to the Socratic Method as it is practiced in the dialogues of Plato, then reading those dialogues (especially the early, so-called Socratic ones) is likely the best place to start. You might train yourself in the Socratic Method the same way the youths around Socrates did, by observing it in action.

You may also find Gregory Vlastos work on the subject helpful.

That said, the method generally works like this: an interlocutor makes a claim, then Socrates proceeds to elicit the interlocutor's agreement to premises that imply a conclusion that is inconsistent with that initial claim- either because the conclusion is the contradictory of the interlocutors initial claim, or because the conclusion is itself a contradiction, absurdity, or falsehood derived from the initial claim.

You can try to put that into practice and annoy your friends and relatives. Have fun!


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

[User]
[Star Wars] I am a formerly Republican, now Separatist Senator during the Clone Wars and one of the other Senators is proposing a bill to invade a planet protected by a Republican treaty. How should I act?

Recently, I have joined the Separatist Alliance, not because I wanted to but more out of necessity.

My people were starving and the Republic Senate did not convince me that they could send help on time. Currently, one of my fellow Senators is proposing a bill to invade a neutral planet. That planet, located in the Outer Rim, is unique because of its culture and technology - being several thousand years behind the rest of the galaxy. It is a part of an experiment conducted by my species in the past.As such, it is protected by a Republic Senate Treaty that does not allow any legal contact with the planet.

However, it is known that the planet harbors resources valuable for the Droid Army, lowering the cost and increasing the production. Morally, I don't think that it would be good for the Separatists to invade the planet since it would disrupt its natural development but economically I realize that this act would only benefit my people. How should I vote?

[Assistant]
Well as a member of the Confederacy, you should realise that you are no longer bound by the Republic's treaties. Also, as an Outer Rim world, it is already likely under the jurisdiction of the Confederacy, whether they know it or not.

Your dilemma seems to be based mainly around a legal system you have chosen not to recognise, a treaty governing territory that is not held by the legal system you do not recognise.

As far as the ethics of the use of resources, did you consult the trees on said planet before you colonised (though more appropriately *abandoned settlers* there)? No? Then why should the Confederacy consult the natives now?


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

[User] Why so many organic substances containing NO2 groups are explosive?

[Assistant]
The N-N triple bond is immensely strong - it's the second strongest diatomic bond.

Forming these triple bonds releases a lot of energy. If you have a compound that contains a lot of nitrogen, you can cause it to release a lot of energy by decomposing into N2 and other products. NO2 groups serve two functions - stabilising the nitrogen atoms until you want the molecule to decompose, and releasing energy themselves as the oxygen radicals rebond to the other atoms.

This is why many explosives are made of nitrogen compounds. It's all about causing the formation of triple bonds to release a huge amount of energy rapidly when the compound decomposes.


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

[User] ELI5: if humans know stuff by instinct I.e. babies sucking a teet for milk, why can't more information be given to us in this way?

[Assistant] Because its not essential for survival and/or too complex. Instinctive behaviors have a survival value; babies who didnt have suck reflex didnt survive. They are not behaviors that are transmitted by an external action (I.e. a mother cant wish for her baby to be born with knowledge of Pythagoras theorem) but behaviors that have developed spontaneously and enabled survival of the individual/species.


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

[User] ELI5: Why does the price of name brand foods vary at different stores but the price of electronics such as video game consoles are the same at every store?

[Assistant]
Food is fairly cheap to produce and the markup is pretty huge depending on the food. A bag of chips that costs 50 cents to make will sell for 2 bucks. That's a sweet margin. And it gives room for discount stores to cut prices and have sales, etc.

Additionally the price of food often fluctuates. The 2 dollar price is a good average that covers increases and decreases in potato costs if there's a bumper crop or famine. There is a theory for example that McDonald's times the return of the McRib with the ebb and flow of pork futures on the commodities market.

Video game consoles have much thinner margins. And the margins are consistent. Aluminum, plastic, and Lithium don't have bumper crops. Microsoft actually sold the first XBox at a loss because they had a longer term strategy of getting into the console market and putting an XBox in your living room as a sort of entertainment hub. Sony is the same way. Their goal isn't for you to buy their console, their goal is to get you to buy into their system. Sony has a stake in BluRay licensing which is why the PS3 was so gung ho on introducing BR discs.

Because these consoles use cutting edge tech, the process required to make them is slow and laborious and specialized. Over time it gets easier and faster and more automated which is why price drops occur later on.

Nintendo is not in the same game, they want their consoles to make profit. So that's why their consoles are cheaper and that's why their tech is a generation behind, because it's easier to make older tech.

In any case, the costs of making a PS4 don't fluctuate the way that potato chips do, and even then, there's not much room for sales.


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

[User] ELI5: Why do we get earwax???

[Assistant] earwax, or cerumen, is produced in the inner portion of the ear canal. It migrates out of the ear canal, and falls out. It does this to clean the ear canal of any small debri and bacteria and to an extent keeps water from pooling inside the ear canal.  Cerumen has antibacterial properties that can kill bacteria trying to crawl in the ear, and flushes it out as it works its way out of the ear. Also because it is open to the external environment, it lubricates the ear canal. It keeps it from drying out. So it does three main things: keeps the ear moist, but not waterlogged, kills bacteria, and cleans the ear canal. All of which to protect the tympanic membrane(eardrum).


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

[User]
ELI5: The logic behind raising taxes for the poor and cutting them for the rich?

Thanks for the answers! It makes a lot more sense now.

[Assistant]
The logic, albeit flawed, is that the "poor" (who generally work for the "rich") don't pay their fair share (to an extent this is true), and that reducing taxes on the rich encourages them to invest it into things that create jobs for the poor. The idea is that by making the rich richer, wealth will "trickle down" to the poor. Hence the phrase "trickle down economics."

This has been shown to not actually work in real life. The only reason the rich are rich is because the poor (the vast majority of the population, and therefore the vast majority of customers) have money to spend on things that the rich make and sell.

Further, when you consider that the poor SPEND most of their income, and the rich either hoard or invest it, it makes sense to use higher taxes to lift the tax burden off the poor so the economy can keep running.

It also makes sense to use taxes to encourage the rich to invest their money into companies that build things and employ people instead of investing it into things that turn money into more money for no real work (buying real estate, stocks, bonds), or worse, hoarding it in trust funds and offshore bank accounts (often to avoid paying taxes on it).

Yes, the richest people often pay more in taxes than the poor make in a year. BUT, when you consider that the rich are only rich because of the infrastructure that our tax dollars built it's only fair that they pay a larger share.

If there was no public education system, you wouldn't have any skilled workers to make your money with. If there were no roads you wouldn't be able to ship your goods far enough to become as rich as you are.

In the end, the rich will end up paying a smaller portion (if not a smaller amount) of their income in taxes because of tax loopholes (ie, because the capital gains tax is a lower percentage than income tax, and much of their income is from investments) and because they spend less of their income, meaning less of their income goes to sales taxes and excise taxes.

This is why Monaco, despite having an 18% tax rate, is considered a tax haven. The poor end up paying a vastly higher effective tax rate (assuming they spend 60% of their income, they would be paying 10.8% in taxes) than the rich (who, assuming they spend 10% of the income, would be paying 1.8% in tax).

I use the terms poor and rich very loosely, of course.


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

[User] ELI5 Are milk substitutes just several plant juices that happen to be white/made to look that way or is there a reason to call them milk?

[Assistant] The concept is to have the salt, fat, and protein levels match the target (cow's milk).  Most almond milks are very close, perhaps a little low on protein, so they work the same in some cooking operations.  It's not just a drink alternative.


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

[User]
ELI5: Can a pilot traveling faster than the speed of sound hear his own engines behind him?

I'm guessing he'd feel the vibrations and the vibrations might make some noise, but does the pilot experience some sort of doppler effect from the engine noise as he approaches the speed of sound and then silence once he breaks the sound barrier?

[Assistant]
A little.

The speed of sound in solids is faster than in air, so some of the engine noise will be conducted by the plane itself.

> does the pilot experience some sort of doppler effect from the engine noise as he approaches the speed of sound and then silence once he breaks the sound barrier?

Yup.  The engine noise would get progressively quieter and lower as his speed increases.


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

[User]
ELI5: Why is it that if something bothered me really badly and had me thinking about it all day, do I wake up and feel completely fine and not as effected?

How does 'just sleep on it' work?
Also this is more for day to day issue or occurrences. I'm sure more serious problems don't just go away when you sleep (I.e. loved ones passing away, unemployment etc)

[Assistant]
Something only is a problem when you make it one, if you are fixated on a bad situation you will focus on the bad parts, not the good parts.

eg: you get fired today, your day is ruined and you spend most of your day pondering about why, how, really???

You go to bed, sleep, shut off the worrying part of your mind, you wake up and have to go to the bathroom urgently, suddenly not having a job does not seem that bad, what you ate yesterday does!

The problem is not gone, and you know this, you still wonder and worry but since it happend some time ago and you had time to relax you also had time to look at things the other way.

Simply put, right after you get fired you are stuck with this idea, and you are unable to put it into perspective untill you stop worrying for a while (eg: sleep). then you wake up and you see the bigger picture.

Not everyone has this, and if this happens frequently to you search for "stoicism", it wont fix your problems but it will give you another view on them and allow you to get past the worry part without needing to sleep it over.


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

[User]
ELI5:Why do you die when you are injected with air?

When someone injects another person with a needle, and it is filled with air, why is it that someone would die from that by heart attack (or cardiac arrest?).

[Assistant] Air causes bubbles, which are surprisingly strong and difficult to force through tiny blood vessels.  As the vessel gets narrower, the bubble gets pinched against the sides and it forms a plug.  When the plug is in a critical place, like a heart or brain blood vessel, plugging it up can kill you.


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

[User]
ELI5: How did currency exchange rates form in the very beginning?

I was wondering how exchange rates formed in the beginning. As in, when the first two countries came together to exchange a monetary deal, how did they know how much of their money equated to the other countries money.

[Assistant] Countries often initially had their currencies locked to a precious metal (typically gold or silver). For example pound sterling (GBP) derives its name from when 20 shillings was literally a pound of sterling silver, under Anglo-saxon rule. These are pretty easily exchangeable because the international value of that coin is its metal content.


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

[User] ELI5: How does super glue (or any such products) dont stick to the equipments making them?

[Assistant]
It's tough.

I worked in a place that made a isocyanate glue for our products.

We used a ton of replaceable plastic items in the production line.   Plastic buckets, replaceable hoses, etc.

We tried to limit the availability of the reactive agent (water in the air, in our case) that the glue comes in contact with.   But eventually everything gets a coating and needs replacement.

Other parts that were metal that could be taken out and left in a solvent bath for cleaning.

Everyday, most of the production equipment that came in contact with the adhesive would be disassembled and cleaned or replaced.

In some cases, we just had to make due without equipment that would be standard in other types of industrial manufacturing.

For example flow meters.  We weren't going to spend a few hundred bucks for a flow meter that would simply seize up after a few days.


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

[User] ELI5: Why does Congress want control of net neutrality so badly?

[Assistant] The telecom industry has made significant donations to help elect or re-elect many, many Congressmen.  The telecom industry also stands to lose a huge amount of money if net neutrality continues.  The Congressmen, who want to continue to receive their donations, are fighting against net neutrality to save their donors' wallets.


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

[User]
ELI5 Why do I never hear thunder during a snowstorm?

I've never heard a snowstorm with thunder before.  Is there something about snow that prevents it from being like rain in that lightning and thunder can accompany it?

[Assistant]
Thunder is caused by lightning discharging. Generally, lightning requires wet air to conduct the electrical potential from high up in the sky to the ground. Dry air isn't very good at conducting electricity.

During the winter, when it's very cold, the air cannot hold that much water. Most of the water will condense and fall as snow. Since the air is very dry, it is less likely to successfully conduct the electricity from the sky to the ground, so lightning is quire rare. Since lightning is rare, so is thunder. However, "thundersnow" is a possibility and has happened before. Again, it's just uncommon.


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

[User] ELI5: How does a computer turn itself on when it's off during a restart cycle?

[Assistant]
The CMOS battery has nothing to do with it. The other response is from someone with a little knowledge but not enough...! The CMOS battery just keeps the BIOS settings from being wiped, which includes the system date and time, when you power off.

A "soft" reboot doesn't power everything down. A "hard" reboot does, and you would have to press the power button to turn it back on. It isn't really any more complex than that, you are just issuing a soft reboot when you restart your computer through software, and it never actually powers off the computer.


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

[User]
Why do comets leave tails behind them when the sun's heat melts the ice? What slows the melted ice so that it trails behind the comet?

I would think, given Newton's first law of motion, that the comet might just develop a cloud of debris that moves with the comet instead of that debris trailing behind the comet.

[Assistant] They are blown away from the sun by Solar Wind; the sun ejects little particles which strike the comet and take little pieces with them. The tail does not trail behind the comet as it moves; it always points away from the sun.


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

[User] [IT] What is pennywise, what is his backstory?

[Assistant]
In the Stephen King multiverse there exists an indeterminate number of universes. There also exists empty space between these universes. Many monsters and demons are born and reside in that space between the universes. *IT*'s true form, the Deadlights, reside in that space between the universes known as the Todash darkness.

One day when the turtle god Maturin vomited a new universe into existence, *IT* decided to travel to that universe and feast upon it. *IT* created a corporeal form for itself that looked like a giant alien spider which then entered Maturin's universe and fell to Earth where it began frightening and consuming Maturin's creations.

Eventually *IT* would make itself look like a human, Bob Gray, or a clown, Pennywise, in addition to other forms to lure his prey in, cause them greater fear, and eat them.


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

[User]
ELI5: How can you tell if a large body of water is frozen enough to walk safely on?

I'm thinking a lake or something like that.  I've never lived in an area where it snowed, and always wondered.

[Assistant]
There's no surefire way to test it.  Most people who go out on frozen lakes do it annually and they just 'know' when the time is right.  And even they get it wrong sometimes.

For what it's worth, all it takes is a few inches of solid ice to support an automobile.  Corollary: all it takes is one feeder creek to make a weak spot, and people fall through.

In any situation where you're going to do this, always defer to the local residents.  If all else fails, you can call and ask the fire department for a recommendation.


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

[User]
Why do philosophers say that Immanual Kants ideas were like the Copernican Revolution of Philosophy?

In science, the Copernican revolution was the insight that forever changed how we viewed ourselves in the universe. We began to view ourselves more humbly and realized the universe  did not revolve around us.

Why do people say Kants ideas were like the Copernican Revolution of Philosophy? From what I know about Kants work and his broader contribution to the enlightenment, I dont understand what warrants this description of his ideas.

[Assistant]
Its just a metaphor, or equivalence. The Copernican revolution was the paradigm shift in cosmology away from geocentrism. Kant's work was (according to this formulation) a paradigm shift in philosophy - especially in epistemology.

What was the Kantian paradigm shift? Instead of imagining our cognition conforms to experience, Kant asks: what if experience conforms to our cognition.

To this end, he described the 'transcendental apparatus' of our minds: the cognitive faculty that has (not just little bits of information but) a way of handling experience which intrinsically imposes an organisation or structure on our experience.


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

[User] ELI5: Why does your face physically change (E.g. Get puffy or bags under the eyes) when you get little sleep?

[Assistant] This may be caused by the blood vessels under your eye. When you don't get enough rest, the blood vessels under your eyes can become dilated, bringing them closer to the surface and causing the area underneath the eyes to swell (causing puffy eyes) and/or appear purple, blue or even blackish in color (which causes dark circles).


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

[User] How does drano unclog drains?

[Assistant] The major ingredients of Drano are sodium hydroxide (NaOH) and, in many cases, aluminum flakes (Al). When dissolved in water, the NaOH reacts with Al to form hydrogen gas bubbles, which help dislodge clogs. The NaOH solution is also strongly caustic (highly alkaline), which helps chemically degrade proteins (into smaller molecular fragments) and fats / oils (into water-soluble components). The combination of physical force (bubbles) and chemical reactivity (reactions with proteins and fats / oils) together help get rid of whatever is clogging the drain.


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

[User]
If we can see 13.2 billion light years away with the Ultra Deep Field, does that mean that the universe was that big 13.2 billion years ago?

So first let me say I am so excited to find this page, Ive been looking for something like this for a long time.

So the universe started x number of years ago (13.6 billion?) and so that is the limit of what we would be able to see. Ultra deep field I believe saw up to around 13.2? Billion light years away (essentially 13.2 billion years into the past).

And I believe it would have been the same story if it was pointed at a completely different part of the sky. And also would be the same if someone way out there had one pointing at us.

Which would make not only everywhere the center, but everywhere also the edge (of the observable universe).

So my question/confusion comes in, because doesnt that mean that the universe was that big that long ago?

Or even more, what if (theoretically) you leap frogged the telescopes, and we saw 13 billion light years away (13 billion years into the past) and then put a telescope there pointing in the same direction, and so on?

I feel like Im making an incorrect assumption somewhere.

[Assistant]
So the current understanding is that the universe is infinite, and expanding at an accelerating rate. This might be counter-intuitive, but it's best to think of it as "everything is always getting further away from everything else" rather than as a bubble with a fixed edge that's expanding into... something.

This means that when we look into the past, everything was closer to each other, but the universe was still infinite in size. We aren't seeing "ourselves" in the past, if that's what you're getting at. We're seeing a distant part of the universe in the past - a part that used to be closer, but now is further away.

As a side note, this expansion means we can actually see objects that are more than 13.6 billion light years away. If you look at something billions of light years away, then it takes light billions of light years to reach us. But the whole time, the universe is still expanding, and the galaxies are getting further and further from us while the light is travelling to us. So even though the light can't have travelled more than 13.6 billion light years, it could have travelled from an object that is now more than 13.6 billion light years away.


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

[User] ELI5: Why does alcohol make your heart beat faster, make you out of breath and sometimes blush?

[Assistant]
Alcohol makes your blood vessels dilate (they get wider so the area through which blood can travel is larger). This answers 2 of the parts of your question. It means that the blood vessels take up more space, so blood vessels close to the skin get even closer to the skin, giving off some heat to the local area and maybe giving you rosie cheeks.

Blood vessels dilating means that there is less pressure within each blood vessel to keep the blood flowing. So your blood pressure decreases. In order to compensate, your heart has to beat harder and faster to return your blood pressure to normal.

Interestingly though if you continue to drink more alcohol, it will actually cause your blood vessels to constrict again.

Not sure about making you out of breath though.


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

[User] If i put water in a microwave it heats up. If I put plastic in a microwave it doesn't heat up. But I assume power draw is the same. Where does that energy go?

[Assistant] The energy is always spent in microwaves (or usually macrowaves) and they bounce around in the microwave.  Any such radiation that doesn't get adsorbed by what you put in the microwave eventually gets sunk into the metal lining the entire inside of the microwave (including the inside of the glass panel) and just pushes around the electrons in the metal there.  The metal is mostly reflective for the radiation, but just like if you shine a visible light into a closed mirror box, the visible light only bounces around so much before it gets adsorbed into the mirrors  the box will be bright inside but not infinitely so.


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

[User]
ELI5: Why are MRI's so huge? why didn't they get smaller in size like computers did?.

Computers went from the size of a room to fit in our pockets, so why are MRI's any different?.

[Assistant] MRI's require a strong magnetic field around your body.  Making a strong magnetic field requires a large magnet.  In some cases, the technology has gotten better and there are "open MRI" machines  where what can be made smaller has been, and you no longer travel through a tunnel to get scanned.  At the very least though the machine must be able to generate a magnetic field around whatever is being scanned (such as your body).


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

[User]
[Star Wars] With No sith and one jedi and a whole bunch of force users coming into powers what does the galaxy look like 100 or 1000 years after The Rise of Skywalker.

Not a question of if the film was good or bad but accepting it as "historical fact"

given we have a Single jedi on one backwoods world and what looks to be a ton of force sensitives and  force users coming into powers what does the galaxy look like 100 or 1000 years

Rey Can't train them all.

[Assistant] I'd like to see 'The Jedi' and 'The Sith' as simply 2 factions in several 'Force' factions that have risen up, they're everything from pure good, through the shades of grey to pure evil. With the deaths of Sidious and Luke Skywalker, good and evil factions alike can say "The Jedi//Sith failed/stopped being a thing for a century because their methods were flawed". These have their own allegiances and agendas, whether its ruling/destroying/protecting the galaxy, or simply being at the whims of the force as they feel it.


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

[User]
[Deadpool] Where did Wade Wilson get those swords, and who taught him how to use them?

[movie] They penetrate into concrete and deflect axe blows from a mildly superhuman guy without breaking, so these definitely aren't run-of-the-mill katanas.  And Deadpool is highly proficient with them, but swordsmanship isn't part of any North American special forces training that I'm aware of.  He wasn't carrying the swords when we see him doing mercenary thug work before his diagnosis.

[Assistant]
Good question. Mix bag of answers here. Also makes some assumptions for the movie.

So historically Deadpool's Katanas are only special because they actually tie into his suit. Utilizing a function of his suit creates an energy field around his Katanas that make them more durable and able to cut through diamond, though not tougher things like adamantium, vibranium, etc.

Other version have his Katanas being made of carbonadium, another strong metal similar to those listed above. With these versions he made them with a caster that wolverine had thrown away.

Idk which versions are considered canon nowadays but typically one of these two reasons is why they don't break.

Deadpool is competent with them because he is actually a master of kenjutsu, a Japanese way of the sword, though where he learned this is spotty in canon again. All versions of him have him with this competency however, it's just when he learned this that is typically unclear.

Deadpools mutations also make him have faster reflexes and peak human strength. He can also push his muscles past the threshold of what they would be capable of normally though this is with great detriment to his body and requires his healing factor for muscle repair. So he is naturally more coordinated with swords in this way as well.

As for why he uses them in the movie, or even in general, it usually doesn't go too far past the aesthetic value of looking cool and turning people into a fucking kabob. Deadpool is actually pretty vain in this way and loves looking cool even if he's the only one who appreciates it.

Going even further than these explanations; as a meta character it's also possible deadpool is aware that he is supposed to use what weapons he uses and that's why he uses them. That's like 16 walls worth of aesthetic value he's not about to pass up. In his movie he is very aware of who he is, the fact that he's in a movie, and his own comic history as revealed at the very beginning when he expresses shock at getting his own movie and having to perform fellatio to an undisclosed crowd favorite. He's been bitching about getting a movie in his comics and in his comics he's aware of the alternate versions of himself, so it makes using the katanas for the sake of keeping his identity on a meta scale viable.


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

[User]
[Super Mario Sunshine] Why wasn't Luigi invited on the trip to Delfino Island?

It seems plenty of Toads were, along with Toadsworth and Peach. I can't imagine Luigi deciding to pass up a relaxing tropical island getaway, especially with the crap he has to put up with in his day to day life. He can't have been busy with his mansion then as Mario beats him to the mansion, so either Luigi's Mansion takes place before Sunshine (but then why would Luigi not want a sunny vacation after a horrifying experience like that), or *after* (in which case what was he doing while Mario was incarcerated and then given community service?).

Did Mario not want Luigi to cockblock him with Peach? Or is there another reason?

[Assistant]
Maybe Luigi was invited, and just decided not to go?

Think about it from his perspective, whenever he tags along with Mario somewhere he gets dragged into some BS adventure having to save Mario's girlfriend (or Mario himself, in the case of the Mansion). He figured that this "relaxing island vacation" would be anything but, and stayed home to get some real R&R with his girl Daisy.


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

[User] [40k] Ork technology runs on low-level reality warping - Ork guns, for example, are random collections of junk that only 'work' because the Orks believe they do. Is there some critical mass required for this? If enough Orks on a planet are killed, will the guns used by the survivors stop working?

[Assistant]
The ability of an Ork to project a Gestalt field expands to the shoota it is using, thus a shoota will always work as long as there's an ork to pull the trigga. A shoota is something small  and orky enough for the user to always project a field upon.

An example of an Ork construct no longer functioning due to the absence of sufficient belief was the scrapworld of Gorro. The planet survived the planet destroying weapons of the Imperium (Keep in mind this was during the Great crusade). It took a ground assault that involved the Emperor himself and Horus leading the charge to kill the Warboss and thousands of other orks to cause the planet to eventually destabilized and come apart due to the fact that the combined Gestalt field of the Orks was the only thing keeping the plasma generator at the center of the planet keeping the whole place together.


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

[User]
[DC] Earth destroys itself in nuclear war while Superman is off planet, what does he do next?

So everyone one on earth is dead and the planet has been rendered uninhabitable for centuries. Earth wars caused its own destruction so Clark doesn't have anyone to like darksied to take out his rage on. What does he do? Does he join a Corp? if so which one? Does he just find a different planet with a native species he looks like him and blend in becoming a new version of Clark? or does he pull a DKR's and farms in isolation somewhere?

[Assistant] If any human Green lanterns are around, they'd probably take him in as they mourn over their loss. He'd definitely take up farming on some isolated planet for a while until Darkseid comes by, revives Earth, then threatens to destroy it again or something.


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

[User] [Mighty Morphin Power Rangers] How important is it that the teenagers have "attitude"?

[Assistant] It's critically important for them to have attitude because zordon wanted the kids to be outsiders, the kind of kid that can turn up missing without raising too many questions.  The kind of kid that no one would believe when they claimed to be involved in an inappropriate relationship with an extraterrestrial column of energy...


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

[User]
ELI5: Why are we still not able to accurately predict the weather?

Why with all of the technology advancements and computer processing capability do we still consistently get it wrong?

[Assistant]
The weather is a very very very complicated system thats why. Theres no simple formula. Its a chaotic system. A small change in one input can radically change the predictions.

That said weve honestly gotten pretty good at predicting the weather a day or two out.


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

[User]
ELI5: How does something like a complex theoretical equation get turned into a real world application?

This is such a brain-smoother for me that I don't even know how to really easily word the question, so I'll try to give an example of what I mean:

In some books I've read in the past, there have been things where they've said stuff along the lines of "If we figure out the necessary equation, we could potentially fold space for faster than light travel."

So, let's say you have your equation, and its principles are sound - how do you then USE this to actually do something? How does it take the jump from theoretical to practical?

[Assistant]
>real world application?

Let's... Use a real world application as an example, rather than FTL travel.

Let's say you want to build a wall, and to prevent it from falling over you want it to be vertical.

If there isn't any wind, you can hang something heavy from a string to show you what vertical is, but if you'd like to be able to work on windy days you'll need a guy named Pythagoras to come up with a handy equation for how to put together three pieces of wood in a way that makes sure the angle between two of them is always *exactly* 90, as long as you know how long each piece of wood is relative to the two other.

All you have to do to turn it into a real world application is a bit of measuring, cutting, and arithmetic.

Or let's say Pythagoras figured that out thousands of years ago and now you'd like to know where you are even if you're lost in a place without streetsigns (such as the middle of the ocean).

You have the technology to put radio transmitters in space, but just using the triangulation that Pythagoras figured out and other people refined *doesn't work* until some guy named Snell figures out how to predict how fast light moves in various mediums, and some guy named Einstein figures out how fast *time* moves at different accelerations and velocities.

All you have to do is fit a battery powered supercomputer in your pocket that can do billions of calculations per second, launch a bunch of satellites, build insanely accurate clocks, and BAM just like that you've turned thousands of years of mathematics into a real world GPS system.


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

[User]
ELI5: Why didn't the Ent, Dwarves, and other races help in the battle for Middle Earth in LOTR.

I've often wondered why the other races of middle earth didn't help in the battle against Sauron. Also, why didn't the other wizards help (I know there are only a few, but still).

And While I'm at it. Why did Aragorn release the Dead Men of Dunharrow before storming the black gate?

[Assistant] Aaragorn released the dead because that is what he promised them he would do.  He could have tried to back out of the deal and try to command them to continue as their king, but that would be a dick move.


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

[User] [Star Wars] Why is technology so advanced, yet so seemingly outdated?

[Assistant] Unequal distribution of technology and resources. Xenophobia and limitations due to biological differences in adapting technology. Prolonged periods of technological regression from war and calamities.


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

[User]
ELI5: At times of water scarcity or contamination (say Flint), why can't we make water using hydrogen and oxygen?

Not a chemistry whiz, but hydrogen and oxygen, in whatever form required, could create water, right? Or other chemical reactions that leave water as a by-product? We can harness nuclear energy, surely we can do this?

[Assistant]
This is a little like asking "If polar bears are made of meat, and we can eat meat, why not keep polar bears around with us so we can eat them if we need to?"

Like a pet polar bear, hydrogen is extremely dangerous.  Like a pet polar bear you would need special containment systems in order to carry hydrogen around with you in anything approaching safety.

Like a polar bear hydrogen is hard to get.

Like a polar bear there are better uses we can put hydrogen to than hanging on to it just in case we need to make some water.


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

[User]
[Star Trek] How do officers from Starfleet and other races understand how to use foreign computer systems almost immediately?

There are some exceptions, like when Data had to work out how to use a computer.  And when the DS9 crew spent a while training to learn the Jem Ha'dar system.

But for the most part they seem to be able to walk straight onto a ship of a species they've never encountered and know how to use a system they've never seen before, in a language they've never seen before.  They must get training to be able to interpret systems, but even so, most of the time they seem to immediately pick it up.

[Assistant]
At the turn of the 21st century earth had already amassed dozens of computer programming languages, hardware schemas, database structures, and other complex computer systems.

By the 23rd century, imagine how many more distinct systems that humanity alone must have designed.

Starfleet has access to not just all of human computer science, but also the other worlds of the Federation, some of which have had spaceflight longer than humanity had civilization.

At the end of even a basic introductory course at Starfleet Academy, a student would have exposure to hundreds of different programming languages, user interface schemes, data structure formats, and hardware designs.  This would probably make them *pretty darn good* at mastering some random thing they happen to stumble upon.

Also, it is not difficult to imagine that part of Starfleet engineering coursework is comparing and contrasting different approaches that the dozens of civilizations have used to solve essentially the same problem: *how not to die in the hostile, unforgiving environment of space*.


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

[User] What causes hair to turn grey?

[Assistant] Pigment cells called melanocytes naturally die as people age. These cells are part of the hair follicle which produces the individual hair strands. When the melanocytes die, the pigment that affected the color of the hair will be present in a less or non existent concentration, which makes hair translucent or, when coupled with 100,000 other hairs, appear grey.


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

[User]
[Hellraiser/ event horizon] are there nice pleasure dimensions too?

Like where people are just eating ice cream and having orgasms and riding roller coasters and hitting home runs all day long? Why do we only find the fucked up chaos torture dimensions?

[Assistant] It seems like when humanity opens an interdimensional door, it's the chaotic entities that most eagerly clamber through it.  They pounce on any opportunity to expand because they're not content alone.  To even approach satisfaction, they need to be torturing, changing, mutilating, converting, enslaving, subverting, or infecting someone.  That is, they need fresh meat to be happy.  But if you're in one of those nicer, contented dimensions, are you going to leap at an opportunity to enter a different dimension?  No, probably not; you're just going to keep eating ice cream.


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

[User]
ELI5: why does it takes 7 months to reach Mars but 2 years to come back?

If humans are to travel to Mars using today's technology, it would take them 7 months to reach Mars and another 2 years to come back. Why does it takes longer to come back? Source: strip the cosmos. Saw it on discovery but they didn't really explained why it took longer.

[Assistant]
The Earth and Mars are both orbiting the sun. Earth makes more trips around the sun then Mars does in a similar time period.  As a result if you launch at the perfect time to transfer to Mars, by the time the craft got to Mars, the Earth would have moved out of position for the perfect trip back.
So you either have to wait for the planets to align again or you take a less than optimal path back.


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

[User] ELI5: Why do we need to attach one negative cable to bare metal when jumping a car?

[Assistant] Lead acid car batteries can emit hydrogen gas (hydrogen sulfide typically) under certain conditions which is flammable. Since we are taught to attach the negative last, it usually creates a spark. Attaching the negative to a point of the car away from the battery puts distance between the spark and a potential (albeit rare) ignition. So safety is the reason. Note that even many sealed batteries can off-gas.


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

[User]
Why not hurl the Parker solar probe into the sun at the end of it's mission instead of letting crash into Venus?

I know at the end of the mission, the solar probe is supposed to be crashed into Venus (or so I think). So, if it's just going to be trashed, why not hurl it directly into the sun and continually take measurements and send data so as to see how close to the sun the probe can actually get before all gadgets stop working; it might also give extra data being closer than the other flybys.

I'm a chemist but not an astrophysicist, so I do have much education in this area.

[Assistant]
In terms of the amount of fuel required to get somewhere, the sun is actually the hardest thing to reach in the solar system. The Earth is orbiting the sun at about 30 km/s, and given the size of the sun in comparison to the distances involved you would have to cancel essentially all of that velocity in order to hit the sun. Reaching other planets is much simpler, because once you've escaped Earth's gravity it takes comparatively minor amounts of fuel to reach any other planet since they're all orbiting in the same plane as the Earth.

You've probably heard that the Parker Solar Probe is the closest object humanity has been able to send something to the sun, and also the fastest object humanity has ever produced? If it were feasible to send probes closer to the sun for scientific purposes it would have already been done. Even the PSP had to use multiple gravity assists from Venus in order to get as close as it did. In order to get substantially closer, close enough to be truly within the sun, it would need to cancel the majority of it's current velocity, which simply isn't feasible. The probe at this stage only has a minor amount of propellant intended to desaturate the gyroscopes, so that it is able to properly aim the heat shield at the sun during perihelion. Certainly not enough to meaningfully change it's orbital velocity.


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

[User]
[Star Wars] How long would Han Solo live in carbonite?

Jaba seemed to want to keep him like that indefinitely. How long would he have lasted? Would he last forever? Could he Philip J Fry himself forward in time for thousands of years?

[Assistant]
If they were using a proper carbon freezing unit, Han likely would have kept for decades or longer. But they weren't.

Before hyperdrives were a thing, carbon freezing was used to keep starship crews alive long enough to reach their destinations. Of course, the process was rough, and it was retired ASAP; spacers would come out of years-long stasis with symptoms similar to Han's, or worse. Over time, the knowledge of how to safely freeze people long-term and build and maintain a "spaceflight grade" carbon rig became more and more niche, with fewer and fewer people having an interest in storing people that way. At the time of Empire, most of the carbon freezing hardware is only intended for industrial use, food storage, and so on, and the hardware isn't really meant for people, meaning that hibernation sickness starts setting in almost immediately after they're frozen. While Han's body would have been preserved nigh-indefinitely, had the rescue taken much longer to stage he likely would have suffered permanent and escalating damage; had they tried to "Futurama" him, they would likely just be thawing out a well preserved corpse.

Edit: wrong word.


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

[User]
ELI5: Why is internet.org a bad thing for India?

People are commenting that this is a bad thing.  But surely a small slice of the Internet is better than no Internet?

[Assistant]
Do you understand why net neutrality is important? Because that's key.

**Net neutrality in general**

In short, common carriers such as phone companies and mail carriers don't normally discriminate based on who is sending or receiving traffic. If they get more traffic, that's good for them because they can charge for those services.

Net neutrality is basically the idea that internet service providers should be treated as common carriers. They don't need to care who you're talking to, only that you're using their services to do so.

However, some companies want to control who you're able to talk to -- they may call it a "fast lane", but the endgame here is that they're able to provide strong advantages and disadvantages to competing services. Imagine if Comcast launched a video streaming service, and then throttled traffic to reduce Netflix video quality. Imagine if Apple got tired of competing with Google Maps, and paid Verizon to add huge lag to any Google-bound connections.

**Internet.org specifically**

Internet.org is a group that wants that control. They're cloaking themselves as a charity that's expanding internet access, but it's actually run by massive corporations like Facebook and Samsung, and they're trying to funnel these new users into using their services specifically.

If Internet.org were *just* about expanding net access, that would be awesome. Unfortunately, it's really more of a recruiting tool for the companies that are funding it.


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

[User]
ELI5 Why didn't humans develop the ability to store protein?

Since our ancestors relied on hunting to survive (before learning how to farm etc) and there wasn't a prey to hunt Everytime they would've benefited from being able to store protein to keep their muscles so that they can hunt effectively right? So why didn't we?

[Assistant] Muscle mass doesn't help you hunt. Look at any hunter gatherers around the world and they're all very slight and built for long range endurance not raw strength. Cleverness makes you a good hunter and our brains require a tremendous amount of energy to function properly, and the most efficient form of stored biological energy is in the form of fats, which is why our bodies pack on fat, rather than muscle. In fact, muscles are very hard to maintain from a physiological and dietary stand point. Just ask anyone who stopped going to the gym for a month, or more.


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

[User]
[Doctor Who] How is The Doctor (and companions) viewed to the peoples they save?

We hear time and time again how the Doctor's enemies view the Time Lord. However, how do the people the Doctor (and companions) save view the Time Lord - particularly regular joes?

[Assistant]
As a warrior. It came up in the devil's run episode, a girl who's people had been saved by the doctor joined one of the universe's greatest militaries for the sole purpose of meeting the doctor and it worked. In fact those people word for warrior was doctor.

While he may argue that he's non violent and doesn't like to kill the results of his actions speak for themselves: destroyed fleets, armies united against him, conquerors and destroyers running in fear. The doctor fights not because he has too but because he wants too and we all know the doctor lies, even to himself.


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

[User] ELI5: What is the difference between bandwidth and download speed?

[Assistant]
bandwidth is how much data can go through the pipe the way you're trying to use it.

trying to upload? your uploadspeed is your bandwidth

trying to download from a source providing the data at high enough speeds? your downloadspeed is your bandwidth

trying to download a huge file from your friends private homepage he's hosting on his old laptop in his room? your downloadspeed is lower than your actual bandwidth (because it's limited by his upload-bandwidth).


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

[User] When someone is sentenced to death, why are they kept in death row for years?

[Assistant] Because they're appealing their case. The government is very lenient about allowing death penalty appeals to go forward (and even *requires* them a lot of the time), because it's impossible to undo or compensate for a mistaken execution.


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

[User]
[Team Fortress 2] How have half these guys kept their jobs?

I'll admit, a good number of the mercs can have their places on the team justified by either uniqueness or demeanor: Engineer is an unparalleled multi-disciplinary scientist, Medic's skilled enough to literally resurrect the dead, and  Sniper, Heavy, and Spy are all professional (if quirky) and don't usually go out to cause problems.

But look at the rest of the team: Scout is brainless and illiterate, Demoman is a raging alcoholic even when he's on duty (and even worse when he's off), Pyro is a violent schizophrenic who's not above attacking his teammates, and Soldier randomly assaults people in public with lethal force (if his penchant for neck snaps is any indication). How have these guys not gotten themselves canned with their antics?

[Assistant]
Because they get results.

The Scout hurts people like grass grows, birds fly, and the sun shines.  He excels at quickly getting to the people who need to be hurt, and then hurting them.

The Demoman's a good demoman because if he were a bad demoman, he wouldn't be sitting here talking about it.

The Pyro is insane, yes, but it's hard to argue he's not effective at burning people.  Sometimes you just need people burnt.

And yes, the Soldier is also insane, but he is also deeply knowledgeable about the history of warfare as well as the origins of zoos.  Well, he believes he is, anyway.  Point is, sometimes you need the kind of guy on your side who will go on a Nazi killing spree all the way to 1949.


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

[User]
[Dungeons of Dredmor] I can pick up this boulder drop plate trap and carry it around. It functions wherever I place it. Does this mean there are boulders hanging from the ceiling to drop on every square in the dungeon?

And by extension, diggle hell and Dredmor's realm.

[Assistant]
The trap is a combination of mechanical and magical devices. Tripping the mechanical trap plate causes a magical portal to open at the nearest surface which is linked to a portal under a boulder.

(Sorta like Portal)


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

[User]
Why can a baby live on milk only, but not an adult?

What do adults need that babies don't? Or would it technically be possible for an adult to live on milk alone?

[Assistant]
Babies can live on breast milk which contains far more fat than cow's milk.  In some countries children as old as 4 or 5 still consume breast milk.

So... when you ask - are you asking about this are you asking if an adult could live on human breast milk?


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

[User]
[Netflix MCU] Where does Nicolas Cage get his name from?

In the real world, Nicolas Coppola goes by the stage name Nicolas Cage in tribute towards Luke Cage, a fictional comic book character.

In the Netflix Marvel world, Luke Cage is a real person, who first appeared in the public eye as a hero of Harlem about thirty years after Nicolas Cage became famous as an actor. Where did MCU Nick get his name from?

[Assistant]
His name was either always Nick Cage, or he picked the name for unrelated reasons.  Perhaps a different obscure comic book character.  Or Johnny Cage, from Mortal Kombat (who must have been a pre-existing character for Nick Cage to have a career in the 80s with that name, since the video game came out in the 90s).

Just like Nick Fury in the MCU doesn't look like the guy who played Mace Windu.

We're looking at an example of Sylvester Stallone playing the Terminator here.


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

[User]
ELI5:Why do I have so much trouble staying awake in class yet the moment class is over I no longer feel sleepy?

So I'm sitting in lecture and it is sooo hard to keep my eyes open when the professor is talking yet as soon as class is over I instantly feel awake. Why is that?

[Assistant]
Because sleep is directly tied with brain activity. When you are sitting in a class (especially one you are not interested in) your brain has very little to do. You have 60 minutes +/- to sit there and take in information from very little sensory input. Combined with almost no physical activity you can see how this starts to mimic sleep pattens. Get comfortable in a location, reduce/eliminate physical movement, shut down creative, problem solving, and decision making areas of the brain, add white noise via the teacher, and you have severely reduced brain activity.

In contrast once you are leaving, you have physical activity, social interaction, decision making, planning, and a host of others things kick back on line.


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

[User] ELI5 what is actually happening when the air above a hot surface shimmers?

[Assistant]
The air densities are different. The air right above a hot surface is hotter than the air higher up. Hotter air is less dense than cooler air, so the hot air rises and it mixes with the cooler air. Since the air has different densities it doesnt mix uniformly (at least not right at the surface) and so the light refracts differently through the differently dense air, and it creates that shimmery, wavy effect.

You can do the same thing with hot and cold water. Pour cold water into hot (slowly) and you can watch the two temperatures of liquid mix together. Before they even out, youll see a similar shimmery effect that you can observe in the air.


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

[User]
What is dialectical thinking? And how can it be applied to the world today?

Help! Trying to find a simplified explanation of the dialectic, with examples if possible.

[Assistant]
So there are quite a few thinkers in history who have used dialectics-- Aristotle, Plato, Kant etc...--however the thinker(s) most people will associate the dialectic with is Hegel, and later, Marx. The dialectic can roughly follow this path: There is a subject/idea/condition that exists known as the *thesis*. This thesis confronts that which is contradictory to it, known as the *antithesis* (anti-thesis). The struggle between these two is resolved by an overcoming of their contradiction. Now Hegel uses the word 'Aufhebung' to describe this interaction which is better understood as a sublation or transcendence rather than the typical translation as a "synthesis".

For Hegel however, this was a process that played out in human consciousness. Marx will take this framework of thesis, antithesis, synthesis/Aufhebung and apply it materially to the world. Marx's theory of history is one in which internal contradictions within a society confront the given social relations, spawning a new society. This historical dialectic that Marx uses tracks the development of slave society into feudal, feudal into capitalist, and capitalist into communist, where the communist society is the final overcoming of the inherent contradictions Marx saw in class society.

The dialectic is used in many of the social sciences and humanities as a tool for inquiry. For example, in comparative politics, the dialectic is used by many--Duverger, Kirchheimer, Katz & Mair-- to track the development in the ways that political parties organize. In feminist theory the dialectic is used by Simone de Beauvoir in *The Second Sex* to put forth an understanding of women as man's antithesis. While not a social science, the dialectic is used in the field of history as a way of understanding social classes and how their competing goals are the engine of historical developments.


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

[User]
ELI5: Entropy, please oh god please.

I have read COUNTLESS explanations, countless examples, countless ELI5s. But I still have no fucking idea what entropy is. Im **not** leaving this earth before I understand what it is. Thank you.

[Assistant]
Over time, shit changes to the temperature of the things next to them. This is true for literally everything, so the temperature of the earth is slowly equalizing to the temperature of the space next to it ( which is very technically not a vacuum since there's tiny particles in it).

"Entropy" is that idea. Things slowly lose their energy over time until the system has equal energy in it, and then nothing can change since it's perfectly equal.

"Heat Death", often referred to along with entropy (so i'm guessing you want an explanation for that too) is when literally everything over trillions of years perfectly equalizes it's heat, and then perfectly equalizes all of it's other forms of energy in the form of heat because heat is bled off every time there's an action (usually in the form of friction). Eventually, literally everything will be an evenly distributed evenly "room temperature" blob, and because there's literally no potential energy left literally nothing more can happen.

*edit: entropy is also a word which can be used when not referring to the physics concept, and in that case it simply means the general concept of stuff eventually falling apart and becoming useless.


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

[User]
Are pterodactyl bones mostly cancellous?

In my Anatomy course, we were discussing cortical bone and cancellous bone. My professor brought up that a lot of flying animals have a lot of cancellous bones in their body in order to lower the weight of their skeletons in order to be more efficient for flight.

If this is the case, has it been found that flying dinosaurs have more cancellous bones than non-flying dinosaurs? Did this make flying dinosaurs weaker predators for bigger land prey?

[Assistant]
1) pterodactyls are not dinosaurs. They are pterosaurs, an offshoot of archosauria, but not part of dinosauria. They are more like dinosaur cousins. They did live in the Mesozoic, but that does not make them a dinosaur.

2) Yes, pterosaur bones were exceptionally thin, hollow, and light. Practically paper-thin walls in some cases. This affects their preservation, and many pterosaur bones are found totally crushed.

3) Most (but not all) of the pterosaurs we know of were largely coastal, and probably fed on fish and other sealife. Probably didn't go after "bigger land prey" very much. For one, pteorsaurs were exceptionally light, with even the largest barely weighing more than the largest modern (flying) birds. Being too heavy makes flight all that much harder.

4) Flying dinosaurs--birds--do have thin-walled hollow bones, but this trait actually long predates what most people would definitively call birds, and is common to one extent or another in many coelosaurid theropods (and maybe even earlier).


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

[User] ELI5: why do people say that diabetes has a low incidence, but a high prevalence?

[Assistant]
Incidence: New Cases

Prevalence: total cases.

Incidence and prevalence are both proportions to the total population, where incidence is new cases that developed during a time period, while prevalence is the total existing cases during that time period.

Basically, it isnt like diabetes is infectious, so just a small group of people develop diabetes at any time. Thats incidence

But, because diabetes is largely manageable now, there are a lot of people who already developed diabetes that are still living with it. Thats prevalence.


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

[User]
ELI5:When I put pressure on my eyes for an extended period of time I see really cool patterns that alternate. What is that?

Also what are those little squigglies that you can see in the corner of your eyes but never directly look at?

[Assistant] your eye is full of liquid called the vitreous humour. when you press on your eyes, you're increasing the pressure of that fluid inside the eye; that in turn causes pressure to be applied to the nerves in the back of your eye, on your retina. those nerves get confused and start sending out random signals that you see as cool-ass patterns.


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

[User] In many models, dark matter WIMPs are their own anti-particles. How are they expected to generate photons on annihilation if they have no coupling to the EM field?

[Assistant] Via loop processes or intermediate particles. An example that we have observed is the Higgs decay to two photons. The Higgs doesn't couple to photons directly (they don't have mass and the Higgs doesn't have an electric charge) but both couple to top and W.


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

[User]
Why do electrons have discrete energy levels they can occupy, and jump from between orbitals, yet do not revolve around the nucleus in orbits?

In class, I learned about the Bohr's model, which introduces the concept of discrete energy levels that electrons can occupy. However, Bohr's model is not accurate anymore as it only applies to the Hydrogen atom, hence debunking the fact that electrons move around the nucleus in fixed orbits, and instead exists in probability clouds.

In this case, how do discrete energy levels exist when fixed orbits do not exist? How do electrons 'jump' from orbit to orbit during excitation/relaxation if there aren't fixed radii of orbits for them to jump to? How do electrons even revolve around the atom then?

I'm so confused, and I think I've got something misunderstood.

[Assistant] An electron in an atomic bound state has a well-defined energy, but not a well-defined position or momentum. Its in an eigenstate of the energy operator, but not of the position or momentum operators.


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

[User]
[Star Wars] Why did the Y-wings die after a single hit from the TIE fighters in the trench?

Aren't Y-wings supposed to be well shielded and take a lot of punishment?

[Assistant]
A combination of a number of things:

* Y-Wings were notoriously hard to repair. Maintenance crews had to basically take the entire ship apart to put in new hull plating on anywhere but the cockpit meaning that they were exposed from behind once their shields were down. (Importantly, they were getting hit *only* from behind on the trench run.)

* On that point, Gold Squadron only had a few days between the battle of Scarif and the assault on the Death Star. They were flying ships that were already battle damaged with no time for a full repair.

* Thirdly, and maybe most importantly, the Y-Wings were not doing what they were built for. They were slow, lumbering ships that were equipped for a 3D space battle. Putting them in a gravitational flight, in a small enclosed trench where their enemies were directly behind them was the worst possible scenario. One good hit and they could easily crash into either side of the wall or the floor. (Notice how when Wedge's X-Wing is hit, he still has enough control to pull out of the trench.)

Basically, they were the wrong tool for the job but at that point the Rebellion had to throw everything they had at the problem.


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

[User]
[Hancock] If Mary wanted Hancock to survive and be a hero that the Earth needed, why didnt she just die and let him be sole survivor?

Watched the movie and it was pretty cool. Their weakness was kind of dumb though. So why not just die and let Hancock be the only survivor?

[Assistant] Because they're inexorably tied together.  If she dies he dies.  The longer and closer they are too each other the weaker they become until they're mortal but if somehow one were to die the other would die at the same time.


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

[User]
ELI5: What happens when a power company generates too much power?

When a power generation station produces too much power what do they do with the excess?  Who pays for, what I'm assuming, is wasted output?

[Assistant]
When you take electricity from a generator, it becomes stiffer to turn. If the engine turning the generator keeps producing the same amount of power, then if the electricity taken from the generator reduces, then the generator (and engine) will speed up - like how if you are driving a car at steady speed with the accelerator pedal still, but then reach a downhill slope, the car will speed up, unless you release the accelerator.

If you connect two generators together, then they will lock their rotation together. So all the rotation of all the generators in a grid are locked together in perfect sync. This means all the generators start speeding up.

The grid manager will give instructions to all the power plants telling them how much power to produce, but they will also give out instructions telling the power plants what to do if the speed of the generator changes. In the US, power plants aim for 1800 rpm generator speed, but the grid manager might tell some power plants that they should automatically start reducing power if the speed goes over 1802 rpm, and, for example, drop down to 50% by 1806 rpm. The exact instructions depend on what the power plant is capable of doing, and whether the power plant operator wants some compensation payments for reducing power.

The power plant operators will try to sell power in advance to utilities in an auction system. Then, they'll tell the grid manager, how much power generation they have booked, and whether they are fully booked, and what price their spare capacity is, as well as whether they are willing to reduce power, and how much compensation they they want if they have to reduce power.

The job of the grid manager is then to try to work out which power plants give the best value for handling sudden unexpected power shortages or power excesses, and let them handle the fluctuations.

Just be glad you don't have to work out all the billing between these different companies, trying to match what was pre-arranged, with what actually happened, and all the billing for the automatic controls, compensation for reduced output, etc.


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

[User]
Why does oil shine in all rainbows colours when it is in contact with water like rain?

I have seen it plenty of times when I have filled my car with gas.

[Assistant] It forms a very thin surface layer on the water. It's so thin that its thickness is in the order of magnitude of the wavelength of visible light. That in turn allows for interference between light reflected on the oil/air boundary with light reflected at the oil/water boundary. What wavelength constructively interferes is also dependent on the viewing angle. Since the surface you look at isn't perfectly flat, you see bands of multiple colours.


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

[User]
ELI5: How or why are people so strong when they do PCP?

I've heard and read a ton of crazy stories about people doing alien-like strong and violent things while they are on PCP. Is this a Hollywood myth or is there a reason? (I have no plans of doing PCP)

[Assistant]
Humans are much stronger than our day-to-day activities suggest.  Normally our bodies limit themselves to keep us from injury, but when these limits get removed you get seemingly superhuman feats of strength.

Examples of this are when you get thrown across a room from touching a live wireit's actually your own muscles doing the throwingor parents under the influences of adrenaline lifting very heavy objects from on top of their children.

PCP is just another way of removing these safety precautions.


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

[User] ELI5: Why does light have speed? Why isn't it instantaneous?

[Assistant]
The speed of light is the speed of causality. It is the fastest speed by which any event can affect anything else in the universe. It is also the defining property of the universe that gives rise to time.

Let me explain.

Imagine a clock. This clock is made by holding two perfect mirrors exactly parallel to each other and bouncing a photon between the two. Every time a photon hits mirror A, one tick has happened. This is our photon clock, and it is a perfect measure of time.

Now, let's say the photon bounces up and down and you can move the clock left and right at any speed you want. Even light speed.

Now, let's take for granted that light moves **ONLY** at light speed. I'll explain why we can do this in a second, but for now, just accept that.

If we move the clock, the photon now has to move diagonally to bounce between the mirrors. The photon's absolute speed must be equal to C, the speed of light. This, we could imagine as the hypotenuse of a right triangle. But, in order for the hypotenuse to be C, the X and Y velocities must satisfy X^2 + Y^2 = C^2 (the Pythagorean theorem). Thus, in order for C to be the speed of light while X is not 0, Y must be less than C.

This means it takes longer for the clock to tick. The faster you go, the bigger X gets, meaning the smaller Y must be and the slower time goes. This is Einstein's Relativity.

I bet you can see where this is going.

If X = C, then Y *must* equal 0 or X^2 + Y^2 =/= C^2. In layman's terms, anything going the speed of light *cannot* experience time.

So, if you were the photon, your trip would be instantaneous. You own clock would never tick.

But, for us, we are the product of light-speed particles moving back and forth and interacting with each other. We are a ticking photon clock. Time is an emergent property of this.

Now, consider what would happen if light was faster or slower. Our own perception of time, which is entirely dependent on the speed of light, would accelerate or decelerate by the same amount. If light was 2x as fast, we'd think 2x as fast and our clocks would tick 2x as fast... which means we'd see it cover 2x the distance it would per *old* clock tick, but our *new* clock ticks are 2x as fast. 2/2 = 1. No matter how fast light goes, we, by definition, must see it go *exactly that fast*, or else we don't experience *any* time at all.

It is also for this reason that light speed is constant to every observer. If you go faster, your clock slows down by an amount that keeps your perception of the speed of light constant.


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

[User] ELI5: Why is it during storms that the lights flicker and then the power goes off? Wouldnt the power either stay on or get cut off? (Hope what I said makes sense)?

[Assistant] The lights flicker because there is a fault, either a short or a surge.  They stop flickering because a protection device has cut in to protect your electrical equipment from harm.  Alas, it does this by disconnecting you from the power plant.  Most protective devices are auto-resetting, they turn themselves back on after 10-15 seconds.  If they trip again, or 3 times in 5 minutes, (or other rules) then they stay off until a human lineman resets them (hopefully after removing the tree that's causing the short).


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

[User] [General] Are Catgirls lactose intolerant?

[Assistant]
Maybe. If they developed similarly to humans, there would be some that could drink milk, and some who couldn't. Most Europeans are lactose tolerant, whereas most Asians are not, due to how long Europe has had domesticated cows.

If there's magical bullshit involved, however, all bets are off. If a wizard who loves feeding his cats milk creates catgirls, he's probably going to make them lactose tolerant.

For the record though, all cats are lactose intolerant. They just like milk for its fat. So you could have catgirls who can't get enough milk all the time, but *shit literally everywhere.*


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

[User] ELI5:after losing some blood, the body starts replacing that blood, how does it know that it has already finished replacing that lost blood so it could stop making more?

[Assistant]
Special cells in the kidneys, called peritubular cells, sense that the level of oxygen in the blood has decreased (due to the loss of red cells) and start secreting a protein called erythropoietin. This passes through the bloodstream until it reaches the bone marrow (the soft fatty tissue inside the bone cavities).

The bone marrow produces stem cells, the building blocks that the body uses to make the different blood cells  red cells, white cells and platelets. The erythropoietin sends a message to the stem cells telling more of them to develop into red blood cells, rather than white cells or platelets.

Your body makes about 2 million new red cells every second, so it doesn't take long to build up stores of them again.

What about your white cells and platelets? A number of other messenger proteins also stimulate the production of these cells in the bone marrow, and over the next few days levels return to normal.


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

[User]
ELI5: Why is the cost of movies/music for personal use still so high when there is way less distro overhead?

This crosses my mind so often, how come we are paying $10-$15 for an album, and the same for a SD/HD movie through iTunes or VUDU or whatever? Shouldn't there be a discount for not providing one with physical media? not having to truck them to stores, make displays and so on? Extra Credit: Is this proving that the artistry is what we are actually paying for and not the physical objects?

[Assistant]
Basically it costs $10-15 to buy an album because people are spending $10-15 to buy one.  The customer perceives value at that price.

Keep in mind that 30 years ago we paid $10-15 for an album on record or cassette.  The innovations in cost savings and distribution you mention are partially consumed by inflation.


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

[User] How do crime families make so much money and manage not to get caught despite their notoriety?

[Assistant] Because most of the time they don't start out as crime families. They are communities banding together to look out for one another when the law fails to do so. It usually falls on local police forces to stop crimes, but when the police force lives locally they are part of the community being protected. The families typically keep violence and petty crime to a minimum while ensuring that everyone has basic necesities. The elaborate crime syndicates are what the succesful organizations become years down the line after they become entrenched and basically control their environments.


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

[User]
Can you ethically justify joining the military (USA/UK)?

I was just wondering whether it's possible to ethically justify joining the military. I am interested in the type of responses people make.

[Assistant]
By just war theory, neither nation has fought a just war since WWII, so its not easy to see a way to ethically serve in their militaries.

There are some bankshot-type arguments you could make  Ill do a better job being a moral soldier than whoever would replace me  but you have to start from a position of defending participation in unjust wars.