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

[User]
What does radioactive waste look like?

People always complain that nuclear power plants create radioactive waste, but you only ever see it in those bright yellow containers. What does it really look like?

[Assistant]
Radioactive waste just looks like rods or pellets of metal. Reactor fuel comes in the form of rods of uranium or other nuclear fuels, and when they're used they look just the same. Also included in nuclear waste is irradiated equipment and more common waste, which just looks like normal except it's radioactive.

Nuclear waste isn't glowing green slime like it's portrayed in TV shows and the like.


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

[User] Why is fusion energy so challenging to achieve?

[Assistant]
Fusion is a really rare process for a given collision. To get relevant amounts of power you need a big volume, a high particle density and a high temperature (~100 million degree). In addition the material shouldn't lose its energy too quickly, otherwise heating power needs to be too high.

The most promising approach is a big hot plasma. To keep it away from the container walls you need giant electromagnets - superconducting coils, otherwise they need too much energy. That is really expensive. And then you get all sorts of problems from the interaction of the plasma with the magnetic field and from the plasma with itself.


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

[User]
How much more advanced and safer is a nuclear power plant built today compared to one built in 1986?

I was recently thinking about how much better computers have gotten in the past few decades, and wondered if nuclear power plants had improved along the same rate of improvement. I chose 1986 because of the Chernobyl incident, but I'm kind of talking about all types of nuclear power not just the Chernobyl type of reactor. (Also I'm surprised there isn't a Nuclear flair)

[Assistant]
Engineering?

Chernobyl was based on a stupid reactor type that is not built any more. In addition the operators were actively overriding multiple safety rules and mechanisms - something that won't happen any more because we have an example how that can end. Another accident like Fukushima is not completely impossible if something really bad happens (like one of the most violent earthquakes and tsunamis in recorded history). Chernobyl will stay a unique event.

It is very difficult and problematic to assign numbers to big accidents. They are so rare that there is not enough data to determine it experimentally.


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

[User] ELI5: How does America benefit from spending so much on military rather than spending more on infrastructure, science, education and foreign aid?

[Assistant]
Military indirectly influences/contributes to a lot of advancements in the private sector.  It greatly sped up the development of the internet, created GPS, vehicle automation is making it's way to consumer cars, cell phones, Jeeps spawned a whole new market of 4x4 vehicles.

I would prefer the government to spend less on military but the knowledge gained from R&D can be quite useful.


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

[User] Why does China keep lending us money?

[Assistant]
China doesn't lend the United States money. The United States hasn't borrowed money since World War I.

What the *Chinese central bank* does not the treasury of the government of China is to buy US Treasury bonds.

Why? Because US Treasury bonds are more valuable to the Chinese central bank than yuan are. The Chinese central bank, like all central banks, holds substantial *monetary reserves* on behalf of Chinese banks. Think of these as being like the money in your checking account. That money has to be stored in some form. The People's Bank of China *could* convert it into yuan the Chinese equivalent of the US dollar, basically and just store them in a vault, but that'd be a poor way to manage their reserves. So instead, they go out to the open capital market and look for securities they can buy, securities that are safer and more secure stores of value than yuan are.

The safest and most secure store of value in the *entire history of the world* is the US Treasury bond. Literally no other store of value has ever been a better choice. The demand for Treasury bonds is enormous, meaning they're always easily convertible to cash in whatever monetary unit you might choose; if you're holding a Treasury bond, you can find somebody with yuan who wants to buy it from you. And Treasury bonds are absolutely guaranteed by law, meaning it's literally impossible for them to be devalued or defaulted on as long as the United States exists as a political entity.

So the long and short of it is that the People's Bank of China has money in yuan and they want a better store of value, so they buy US Treasury bonds because they're the best store of value in the world.

So why do people characterize that as "borrowing from China?" Because Treasury bonds *mature,* and when they do, the Treasury buys them back from whomever holds them for their face value in dollars. If you have a Treasury bond that's got a face value at maturity of $1,000, then when it matures you turn it into the Treasury in exchange for $1,000. Treasury bonds also pay interest, although the rates are *incredibly* low, because they're not meant to be profit-making investments; Treasury bond interest rates basically hover around the rate of inflation of the US dollar, meaning the *value* of a Treasury bond investment stays even though dollars gradually become worth less over time. That's what makes them a great store of value: A Treasury bond ends up being worth more dollars than you paid for it, but the value of that sum of dollars remains pretty close to constant over time.

So it's "borrowing" in the sense that the Treasury has to pay interest to the People's Bank of China every six months, and the Treasury has to exchange the People's Bank of China's bonds for dollars as they mature. But it's not *really* borrowing, because whenever the Chinese central bank gets dollars either as interest payments or bond redemptions, they turn around and buy more bonds with the dollars for the same reason they wanted bonds in the first place: because bonds are more valuable to the Chinese central bank than monetary units like dollars or yuan are.

(And since this always comes up, the total value of the US Treasury bonds held by the People's Bank of China is, at present, roughly *eight percent* of the value of all the outstanding Treasury bonds out there. Meaning no, despite what some people like to say, China does not "own" the United States. The value of the Chinese central bank's bonds is *insignificant* next to the value of the bonds held by people like you and me, ordinary citizens, in our safe deposit boxes.)


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

[User] Is there a psychological reason we recognize happy/sad melodies, or is it just that we're used to the context?

[Assistant]
Not so long ago major keys were considered 'happy' and minor scales considered 'sad'. But it has been determined that that is just conditioning.

Also in music there is the idea of tension. Try singing the first 6 notes of Twinkle Twinkle Little Star, leaving of the seventh ("star"). That distinct sense that the melody has been left uncompleted is *tension*, and the seventh note is thus said to "resolve" the tension. Always resolving the tension makes for more positive effects of the listener, so nursery rhymes will reliably always resolve tension.


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

[User] [general henchman rules] After revealing his entire plan and taunting some do-gooder we captured, my boss just gave me a meaningful look and nodded at me. Am I supposed to know what that means? Do I take the hero guy down to a jail cell, beat him up, kill him, or what?

[Assistant] He won't like it if you ask for instruction, but he really won't like it if you do the wrong thing. If you could try asking another henchman, but if that doesn't work you'll need to ask for clarification. If he's one of the really bad bosses that might kill you even for that, then you should release the hero as a distraction and run for it.


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

[User] ELI5: Most languages are written left-to-right, which seems to make sense since the majority of people are right handed. Why are some languages, like Arabic or Chinese, written right-to-left and/or vertically?

[Assistant]
Some of the most ancient written languages read right to left because they were originally carved with something like a hammer and chisel. You normally hold a chisel in your left hand and swing the hammer with your right. This created a natural right to left motion; also, if your chisel slipped it wouldn't gouge through figures you had already carved.

Later writing was done by making impressions in a clay tablet with different shaped reeds. Top to bottom or left to right made more sense because your hand wasn't hiding what you had just written. Even later, when pen and ink were being used, left to right was favoured because it ensured that you wouldn't be dragging your hand through wet ink.


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

[User]
If black holes are infinitely dense. How can they have different sizes?

I've heard that black holes have 0 volume and that they are infinitely dense.

What exactly does this mean?

I know there is something I'm not getting because I've heard that black hole the size of a peanut would have as much mass as the earth. This wouldn't be true if all black holes had 0 volume.

[Assistant] The "size" of a black hole refers to an aspect of its gravitational reach, not it's physical size. The physical size of black hole is still infinitely small. The size of the event horizon (where space time is warped to the point that nothing can escape- aka it goes "black") is proportional to it's gravity, and thus its mass.


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

[User]
[Edge of tomorrow] How do mimics sustain themselves?

What do they eat? How are they making those missiles that shoot down the drop ships?

[Assistant]
In the novel's universe [\/meta], It is speculated the Mimics are essentially an engineered weapon.  The "seed", well the one that wasn't recovered before it went active, hit the middle of the Pacific Ocean.

Then it began "mimicing" the creatures it found under the assumption said creatures must be near ideal for the world.  That's why the the things look vaguely lovecraftian.  They encountered deep ocean floor creatures and then amphibians and then finally land creatures as they worked their way up the continental shelves.

So the Mimics are likely cyborgs, for lack of a better word.  They probably don't actually eat as eating would be inefficient for such designed creatures, but are crafted or spawned based on whatever materials are available.


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

[User] [Star Wars] How would the First Order have been dealt with if someone like Garm Bel Iblis was elected chancellor of the New Republic?

[Assistant] Nothing changes, Mon Mothma was barely able to keep the senate functional, and though Garm is no slouch he's not going to do strictly better than her on the diplomatic stage. Garm defects to the Resistance rather than play minder to the senate.


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

[User]
[Harry Potter] What did Hagrid mean?

When Hagrid came to get Harry from his aunt and uncle, they claim that his parents died in a car crash, to which Hagrid replies:

"How could a car crash kill Lily an' James Potter?"

Obviously, we know that the Potters didn't die in a car crash, but the way he says it implies that not only did they die another way, but that the Potters simply couldn't have died even if they were in a car crash. What did Hagrid mean then?

Possibilities I thought of:

1. Hagrid doesn't know what a car crash is.

2. Hagrid knows what a car crash is, but wizards have increased toughness as a result of their magic, and thus would not die if they were in a car crash.

3. Hagrid knows what a car crash is, but is confidence that the Potters would have used magic to save themselves if they were in a crash.

4. Hagrid's memory of the Potters is biased by the legends surrounding them already, and thus it is inconceivable that such great wizards could go out in such a way, despite how very possible it actually is.

5. Hagrid was just insulted that someone could imply that the Potters had died in any other way, simply because of the memory of them and the legends about them.

[Assistant]
Its possible he meant that they didn't own a car, being wizards, and would therefore never be injured in a car crash.

Not to mention that wizards **do** seem to have signifcantly increased toughness as a result of being wizards.  Or else there's a lot of safety magic built into that quiditch field.


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

[User]
[Wonder Woman] Does wearing the Lasso of Truth on her hip force Diana to be brutally honest and forthcoming at all times?

According to at least some depictions, just touching the Lasso is enough for it to work. Diana lets it dangle from her hip. Does this mean she is forced to answer any question asked of her, and be brutally honest to anyone she talks to? Sort of like that Jim Carrey movie, Liar Liar?

[Assistant] According to many depictions, Wonder Woman can neither lie nor be deceived, whether she has the lasso or not. In general, she is depicted as being fundamentally honest, which is part of what makes her worthy of wielding the lasso.


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

[User] ELI5: do horses or other animals appearing in battle scenes in films/TV understand that they aren't actually in danger?

[Assistant]
Horses have roughly the intelligence/mental capacity of a 3 year old and are engineered to be easily spooked. Battle horses would have to go through extensive training not to fear the battle scenario in general.

Now that we have real battle out of the way, most TV show and movie filming is heavily doctored and the horses highly trained to execute what is needed for the filming. They know they are doing a trained job and there is no danger in general and the environment wouldn't really cause them to spook easily anyway.


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

[User] ELI5: What is that sinking feeling in your stomach, blood warming throughout your body feeling you get when you hear bad news?

[Assistant]
Your nervous system has two main modes, one is the well known "Fight/Flight" and the other is "rest and digest".

When you've just eaten and feel safe, you want lots of blood flow through your gut to help absorb all those nutrients. You're in rest and digest mode.

If suddenly a tiger attacks you, the fight/flight mode kicks in, releases a bunch of adrenaline to get you going and tells your body that digesting food isn't as important as running away.

Now we're not too good at unconsciously telling the difference between a real and perceived threat. When you get bad news, your body feels like there is a threat to it, so the fight/flight mode kicks in, blood flow to your gut is reduced (giving you that sinking feeling) and the adrenaline gets your heart pumping faster, warming you up a bit.


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

[User] ELI5: Why does online credit card fraud still work? Aren't those who use a stolen card # identified / prosecuted once they send something to their address?

[Assistant]
Long time lurker and also a fraud investigator.

A lot of times hackers will steal a large number of credit card numbers and sell them in lots of hundreds or thousands. The buyer of the credit card numbers will typically set up some type of account where they will charge all of the cards for small amounts, say 10 or 50 cents, and make it a recurring charge. Many people won't notice these small charges, so they will continue to be charged weekly.

1000 cards weekly at 50 cents is $500 a week.

They will then launder the funds by using them to purchase bitcoins, or moving money off shore.

The amount of time to investigate this type of crime and try to bring the case to prosecution is typically weeks or months. For that small amount of money most companies will just cancel the card numbers and chalk it up to a loss.


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

[User] ELI5 Money laundering. I've seen all the tv shows and I still don't fully understand how you "clean" it.

[Assistant]
You need a legit business that deals in cash, say a car wash.

Then, let's say you cook the best meth in all of New Mexico and you need to be able to use the money you make selling it to pay for legitimate stuff, like cancer treatments.

Now, you'll slowly bring some of the cash you made selling your meth to the car wash and give it to your accountant wife, who is in on the game.

She will create receipts for things that never happened and attach them to the illegally gained cash. She'll probably tell you to dump out some car carpet shampoo and such to support the fake receipt.

Now, just bring all that cash to the bank and deposit it into the car wash's account.

You'll probably run into a problem with having to launder too much money to stand an audit. So you probably should have set up a chicken fast food restaurant with a lot of locations.


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

[User]
ELI5: how is fish not considered meat?

It's lent season here in the USA, and once again I'm left with the question of how fish isn't meat.  For those outside America, catholics here have a tendency to give up meat for lent - I understand that lent works differently outside of America.

Anyway, fish are (questionably) intelligent life forms much likeI any beef or poultry; so how is it that they are not considered meat?

[Assistant]
Lent is a thing in the Catholic church.  The Roman Catholic Church.  This was the church of the Roman Empire.  For centuries, services were done in Latin, as were all official church rules.  They used to have a rule (which is still widely followed, but not required) that said "don't eat meat on Fridays".  When it was written in Latin, it used a word that meant "pigs and cows but not fish".

If you look at your day to day life, you go to a butcher for "meat" but a fishmonger/market for "fish".  They're also in separate cases at the supermarket.


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

[User]
[Star Wars] What kind of protection does a Stormtrooper armor offer against blaster fire?

Whenever a stormtrooper gets shot by a blaster, they just fall down and appear to be dead. But are they dead for real?

I recently saw Kenobi's 5th episode. In it, Tala >!gets shot and without any armor, stays a live for a while. In fact, she doesn't die from the blaster shot, but dies as a result of the explosion that she herself initiates.!<

So, if the armor doesn't help against blaster shots, what's the purpose? Just as a uniform? But I guess the Empire could save quite a lot of credits by using some cheaper non-armor uniforms.

[Assistant]
Stormtrooper armor is designed to absorb or deflect glancing blaster bolts. It is relatively useless against slugthrowers, piercing weapons like arrows or spears, and offered little protection against concussive weapons such as clubs.

Ultimately the armor served to anonymize the stormtrooper. The Empire relied on overwhelming numbers of faceless troops to maintain order. If one stormtrooper fell, two more would step in.


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

[User]
ELI5: Why do words hurt?

I've just been thinking about it, and I'm genuinely curious why people can be so affected by them, is there an actual reason our brains take a nasty insult worse than a punch?

And also why some people can easily shrug off insults, where it can completely break others.

[Assistant] Human are a social species. How others perceive us is very important to our future success and well-being. So, discovering that someone disrespects you is a somewhat serious problem. It's not the words themselves, it's what they imply about your status.


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

[User] ELI5: If using q-tips is dangerous, how are you supposed to clean your ears?

[Assistant] You generally don't need to 'clean' deep in your ear canal, just wash the outside like you would the rest of your body. But if that's not enough try using a syringe (no needle) to squirt warm water into your ear. There are also softeners to help the removal.


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

[User]
Do any animals besides humans abstract Vitamin D or any other nutrients from sunlight?

Excluding all plants and such.

Edit: Extract Vitamin D*
Wow...I was really tired when I wrote this question.

[Assistant] No nutrients are extracted from sunlight; sunlight merely is a form of energy.  Plants use the energy in sunlight to power a process that adds carbon from CO2 gas onto sugar molecules which are used for sustenance.  Mammals also use the energy, but for a much more limited/less critical purpose.  Mammals use the energy of UV irradiation in sunlight to to convert a vitamin D precursor (7-dehydrocholesterol) into actual vitamin D (D3, cholecalciferol). This is just dependent on UV irradiation so there's nothing special about sunlight--it'll happen if you sit under fluorescent lights inside as well.


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

[User] [DC] how much protection would Superman's suit offer to a non-Kryptonian?

[Assistant]
Action Comics #0 shows a child (wrapped in the cape) in an abusive home attempt to be killed by his father. The cape breaks the knife upon impact. It's probable that it is very nearly as indestructible as he is.

So a lot.


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

[User]
ELI5 What is inductance?

Like resistance is when there is hindrance towards the motion of electrons in an object. Then on similar lines what is inductance?

[Assistant]
The best way to imagine how an inductor works is a water propeller analogy.

The current speeds the propeller and while its speeding generates resistance, if the current stops the propeller will still move the current while its slowing down, if the current goes against the proppeller it will oppose more resistance but also try to chanage the way its spinning.

If the current changes the proppeller will oppose resistance to the change while also changing to match the current.

Inductors offer resistance in alternating current, in direct current they offer no resistance.


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

[User]
Should we be afraid of death?

Epicurus said: Death is the eradication of senses. Without our senses, we can't feel, so it would be stupid to be afraid of death according to him. I know it is imperative and natural for humans to die, and when someone dies we think ''he is in a better place now''. But we don't know what comes after death at all, so how can we say that? How can we not be afraid of death if it isn't something we understand? Why do we have a survival instinct? Are we afraid of suffering? of the unknown? or dying?

[Assistant] mostly going off heidegger here - i think that 'anxiety' is a better word to describe the way we fundamentally orient ourselves towards death. the uncanny thing about death is its incommensurability with our way of being. we always orient ourselves temporally towards the world, but death apparently represents the impossibility of a future to project into, while simultaneously being unavoidably in our future. so, we encounter a deep uncertainty about our basic existential constitution in the very way we always already orient ourselves towards the world; this seems like a good candidate for 'anxiety,' as heidegger calls it.


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

[User] Eli5: Why do warmer climates have turquoise, clear seas and white beaches? Why is my sea so gross in comparison?

[Assistant]
If you are imagining tropical islands the answer is that the sand is primarily derived from coral atolls/reefs.  The coral has a white skeleton when it perishes/breaks away.

The reason the water is blue is because these islands are the only land masses in an open ocean.  The open ocean has significantly less nutrients than near continental landmasses and hence there is less plankton / sediment colouring the water green / brown.


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

[User]
[Fallout] How on earth was the Ripper ever considered a good idea?

It's loud as hell, does jack shit against armor, it's hard to control, and it would run out of fuel in a matter of minutes. How on earth did it see "extensive use in conflicts before the Great War" per Fallout 4's loading screens?

[Assistant] The ripper is a terror weapon. It's designed to cause extremely awful wounds and deter people from further violent action. Remember, a lot of the conflicts before the Great War were internal. People were rebelling against governments that weren't functional any more and couldn't provide for their basic needs. Forget nonlethal anti-insurgency tactics like water hoses and sonic weapons; would you keep trying to rebel if you watched your friend get a massive chunk taken out of him by a cop wielding a chainsaw-sword? Heck no. It's one thing to charge a line of police if they've got billy clubs, but nobody does that if they're going to get hacked apart by chainsaws. The ripper is a weapon designed to instill terror; it doesn't have to be effective, just AWFUL.


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

[User]
Why is it better for Lithium-ion batteries to be charged after a partial discharge and not a full discharge, unlike the Nickel-based batteries, which had a memory-effect that caused them to hold less charge if they got charged repeatedly after being only partially discharged not fully discharged?

According to battery experts , It's always better to charge lithium-ion batteries every time you could, and It's not recommended to wait for a full-discharge and then do a full-charge, unlike the Nickel-based batteries, Why is that?

[Assistant]
Lithium batteries will degrade if left in a low charge state. To get the capacity/run time out of a battery cell, manufacturers will let you push the device deep into the discharge state. But this comes at a cost of decreased lifetime.

Since lithium cells have no memory like NiCd, it's best to charge them promptly. Although long term storage of a lithium cell at full charge isn't healthy either, but not as quickly  degrading as discharged state.

For longest life of a cell, discharging to 20% capacity and charging to 80% is generally preferred.


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

[User]
ELI5: Why do we board up the windows of abandoned or currently renovating buildings instead of leaving the glass?

A small apartment building near my house is being renovated and theyve removed all the windows and doors and covered them with plywood. Presumably there wasnt a problem with EVERY window, so why take them all out and board them up? I imagine they were intending to replace them, but why take them out as the very first step in the reno?

[Assistant] Doing so prevents injury risk if they break during other renovations on site.  It also mitigates against vandalism, as well as break-ins.  And, as you noted, all windows would likely be replaced anyhow.


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

[User]
(Marvel/MCU) Why doesn't Iron Man make suits for the rest of the less-powered Avengers?

I did a quick look and I didn't see this question anywhere so I thought I'd ask. But why doesn't Iron Man make a suit for Captain America, Black Widow, or Hawkeye? Wouldn't a team full of Iron Humans be a better option than what some of the more low-powered and non-powered heroes offer? Hell even Beast or Pym could benefit from a suit more than what their powers offer for the team.

[Assistant]
Many people have worn an Iron Man style suit in the comics. Happy Hogan was Iron Man for a while. Norman Osborn wore one for years, all while he was in charge of the then equivalent of SHIELD. Spider-Man had one, complete with repulsors. Pepper has an entire suit dubbed Rescue just for her. Tony is making stuff for the Avengers all the time.

That being said, in the comics at least, a few years ago Tony was infected with the Extremis virus (similar to the movie version in name only) and gained a crazy amount of technopathy, even going as far as to intercept text messages in mid-air. At this point the suit and Tony are the same person, and getting someone else to that level of cyborg-ness isn't exactly easy. Iron Man and Tony have a very symbiotic relationship at this point. Not exactly something you can just manufacture and slap on Thor.


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

[User]
Since heat transfer is caused by random collision of particles, is it mathematically possible that your hand could touch a hot pan and you actually heat up the pan with your hand?

I know the probability of this would be inconceivably small so it would never actually happen, but is it mathematically possible that: because heat transfer is based on random collisions of particles, all the hot particles just so happen to bounce from your hand to a hot so that the net heat transfer is positive? This would mean that instead of the pan heating up your hand, your hand transfers even more heat to the pan.

Sorry if I'm misunderstanding physics, just a fun question I thought of.

[Assistant]
>I know the probability of this would be inconceivably small so it would never actually happen

Yes.

>but is it mathematically possible that: because heat transfer is based on random collisions of particles, all the hot particles just so happen to bounce from your hand to a hot so that the net heat transfer is positive?

Yes.

The second law of thermodynamics says that entropy tends to increase, and in any realistic thermodynamic system, entropy is **much** more likely to increase than decrease, even though it's technically not impossible.

Increasing entropy implies that heat must flow from higher temperature to lower temperature. So the situation you're describing would mean that entropy is decreasing, so you'll never observe that in any realistic situation.


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

[User]
why don't humans regenerate limbs?

We all grew limbs when we were in the womb originally and from what I've heard after some amount of time there isn't a single cell that is still with us from before.  Why can't we regenerate limbs?  It seems that the ability is there to do so.

and will science ever be able to progress to where we can regenerate limbs?

[Assistant]
In short, because the cells mature to a point where they lack the capacity to regrow. Remember, there are four tissue types involved in the process.

Epithelial cells by far would have the highest regenerative capacity, but remember, in a burn, if you lose the basal level, skin won't regrow. That's where the stem cells are, so people who have lost that level require grafting. Without skin, the arm would be a huge liability to the organism, as it would provide an easy route for infection.

Next, there's connective tissue. Ignoring all of the other types present, we'll focus on bone. The long bones of the arms and legs develop via endochondral formation, where the "growth plates" are made of a cartilage matrix that expands and slowly calcifies. The chondrocytes die and are replaced by osteoblasts as we mature, leaving us with bones. Bones can be repaired, but not regrown.

Muscles are also going to be a pain. Skeletal muscle does have some regenerative capacity, it is limited. Hypertrophy of the cells is the normal response to working out, meaning that the existing cells grow. Hyperplasia, the act of cellular replication, is usually not a good thing in the case of muscle, but would be required for regrowth.

Nervous tissue, which would allow the arm/leg to have any function, is the least regenerative. There is some evidence of nervous stem cells coming to light, but they clearly have a very limited capacity to work, considering the permanence of brain damage and paralysis. Even if you could grow the bone, skin, and muscle, without the nerves, what's the point?

As each of these tissue types matures during embryogenesis, they lose the capacity to revert to a less mature state. What we refer to as "adult stem cells" are cells with the ability to replicate, but only within the cell line that they have chosen. They can't proceed backwards to pleuripotent embryonic stem cells under normal conditions. There has been experimentation with reverting cells ex vivo that has shown some success, but this is mostly being researched for things such as regenerating heart muscle or nerves (things without regenerative capacity). So is it possible that we may progress to where we can regenerate limbs in medical practice? Maybe. But it's nowhere near a reality, seeing as we are still struggling with regenerating one tissue, let alone synchronizing the development of all of the tissues in a limb.

And all of this is not to mention the risks with reverting our cells to stem cells. Keep in mind that a reversal to a less mature state is one of the hallmarks of cancer, meaning that minor errors on a genetic level could predispose the patient to cancer, and the more we have to do, the more likely we will be to make that little mistake. (Our cells make mistakes in replication on their own about 1/1,000,000 times.) While it may seem a worthwhile endeavor at the time to give a person their arm back, giving them malignant cancer that kills them before the limb can even fully grow would make the whole thing moot.


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

[User]
I do not see anything morally or ethically wrong with polygamy. CMV

I think I can sort of understand economic issues with how marriage laws work in relation to benefits and taxes -- in these cases I could see polygamy as a clever method of tax evasion or something of the sort. Also, I see that it is morally wrong when, say, one partner is not aware that there is a third partner in a certain marriage/relationship. But personally, I see nothing morally or ethically wrong with polygamy if it is between clearly consenting adults. CMV! :)

[Assistant]
Are we talking about polygamy in an ideal world, as an abstract, or polygamy in a world where wealthy men frequently compete to accumulate as many beautiful wives as possible, replacing them as needed, while their sons are treated as disposable and unwanted pieces of trash?

Because polygamy is beautiful, until you bring all that ugliness into it.


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

[User]
Do we hum and sing songs to ourselves to release dopamine without actually listening to music?

As per title.

[Assistant]
Kinda! Humming and singing songs can be considered a vocal form of what is called stereotypy, which is basically any repetitive behavior that feels good on its own, such as finger/foot tapping, hand drumming, hair twirling, etc. When these behaviors occur frequently when the individual is alone, we can assume that the sensation itself may be keeping the behavior going. Since that sensation is reinforcing, it likely releases some dopamine to the brain to get that behavior and good sensation going. If this only occurred in social contexts now, it may not just be the sensation of humming and singing that is keeping the behavior going, but perhaps the attention of others (positive or negative)

Everyone engages in stereotypy, although it is a characteristic of many autistic individuals to engage in it excessively, often in "bigger" topographies, and regardless of context. This may be partially due to social consequences being less impactful to reduce these behaviors, but still providing them with this sensation, which may or may not be more intense than what a neurotypical individual would experience.


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

[User] [The Flintstones] If cars in Bedrock are powered by running, why even bother with the car?

[Assistant] Once they get up to speed, the cars just keep going. It isn't like you have to keep running like you normally would without the vehicle. And it's possible for one person to power a car containing multiple people.


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

[User] [Harry Potter] Despite its danger, why didn't the Order of the Phoenix use felix felicis during critical times?

[Assistant]
You kind of answered your own question. It's dangerous, too much use causes wrecklessness, and it doesn't make you a god it just makes you feel hyper confident and puts your luck stat at 11.

Its toxic in large quantities too, and very hard to brew properly. Not easy to just make the stuff.


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

[User]
ELI5: Why does a candle produces so much more smoke after it is blown out?

Seems like they are not producing any smoke while burning. (At least not noticeable)

[Assistant]
A candle burns with enough heat that the wax gets completely combusted into CO2 and other gas-only products. Wax-vapour that hasn't combusted is still hot enough to spread out by natural convection.

When we blow out a candle, the temperature drops. Wax still on the candle can no longer combust. The smoke we see is not a gas, but rather tiny droplets of solid / liquid wax, much like water-droplets in a cloud.

Once we blow out a candle, any wax-vapour that remains in the air has no option but to stay there - as smoke.


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

[User] ELI5: the difference between 32-bit and 64-bit Windows installations, and their relation to the hardware.

[Assistant]
Think of a computer like a great library. There are all kinds of books (storage) but also a librarian who helps figure out what books you need. The librarian has 32 assistants who help fetch books on bicycles and bring them back to the librarian. If someone comes in wanting all the books on dinosaurs, and there are 65 of such books, the books will all get there in three trips. The first trip all the assistants go out and get the books on, then go back and on the second trip they all get another book and on the third trip only one has to go and get data, but it still takes just as long, since the important thing is how long a trip takes.

So to get the books it requires three bicycle trips (but we can just call them cycles, so three cycles). However, if the librarian had 64 assistants, it would only take two cycles. There would be a dramatic speed boost, but NOT double, since there would still be on trip that only one assistant was needed, while the others are there but unable to make it go faster.

If there were 256 books on dinosaurs, then with 32 assistants it would take 8 cycles but with 64 it would only take 4. However, if there were only 20 books on dinosaurs it would make no difference if there were 32 assistants, 64 or even 128! It would still just be one cycle.

A computer works in much the same way. The computer fetches data from memory, but can only fetch so much at one time. If the computer is running at 64 bits, it can fetch 64 bits of data (and work on it) during one clock cycle. A computer running at 32 bits can only handle 32 bits of data during a clock cycle.

Well, now imagine that there were 64 assistants, but the librarian didn't know where half of them were! The librarian could only use 32 at a time, even though there were twice as many available. A 32 bit version of windows only knows how to "find" bits worth of data at a time, even though your 64 bit computer has other resources waiting that cannot be used. The 64 bit version of windows doesn't change the hardware any (of course) but it helps the hardware FIND all those assistants.

EDIT: And although this wasn't asked for, a dual core processor is like having two librarians, and the "speed" in gigahertz is how fast the bicycles can go. (Or more specifically, how long it takes them to make the trip. A 1 Ghz bicycle can make one billion trips in one second.)


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

[User]
ELI5: How do storage containers keep cookies crisp when they have air inside them?

How do containers like Tupperware stop cookies and crackers going soft since there's still air inside the containers with the food?

[Assistant] They go soft because they are absorbing moisture from the air. When out in the open, there's an infinite (for all intents and purposes) amount of moisture for them to absorb, but when closed in a container, they can only absorb the moisture in the small amount of air in the container with them. At some point, the moisture level in the air reaches an equilibrium with the cookies/crackers and they don't absorb any more. The same thing happens with things that go stale, like bread, but in the opposite direction. They want to dry out, but when in a closed container the air inside can only hold so much moisture. The rest is forced to stay in the bread so it stays soft.


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

[User] [WH40k] What is the size difference of the Imperium post heresy as compared to pre heresy?

[Assistant]
I believe the actual size of the Imperium remained the same, more or less. While some planets may have turned traitor, they would have been reclaimed once Horus was dealt with and brought back under Imperium rule. That being said, the Great Crusade wasn't finished when the Heresy started, so many parts of space were still undiscovered. Given the 10,000 years between settings, it's actaully possible that some of this unexplored space would have been settled.

In summary, the Imperium was likely to have grown after the Horus Heresy, though their gains would be small and barely worth noting.


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

[User] (Star Wars) How does gravity work on board a massive object like the Death Star?

[Assistant] Even though it's very big by ordinary human scales, the Death Star is tiny by astronomical scales. It has negligible gravity of its own. Gravity on the surface and the interior has to be created in the same way it's created aboard spaceships. (Ahem. Whatever that is.)


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

[User]
Why inbreeding animals causes so much harm to offspring, but it is not the case in case of plants?

I am curious what are the reasons that inbreeding animals leads to the higher probability of many genetics disorders, but it seems not to affect well-being of plants? Or am I wrong here and inbreeding plants also damages DNA of next generations, but maybe less, than these of animals?
Also as far as I know number of chromosomes in plants can vary with no or little effect on them. Why is it like that? Would that be on of the reasons why inbreeding is not dangerous to plants?

[Assistant] Plants dont respond to it too well either. The best example is apples because theyre super inbred to protect the distinct flavors of each type. This makes them prone to diseases and fungus and require a lot more pesticides than other crops.


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

[User]
[Fallout] How was Vault-Tec expecting to monitor the Vaults after the atomic war?

What I don't understand about Vault-Tec is that they designed these vaults to be used as experiments following a full nuclear war. How were they expecting to study the effects decades or centuries down the line? Was there a special vault reserved for Vault-Tec executives and scientists so that they could continue their research? What were they even expecting to gain from it considering the world as they know it would have changed so much?

[Assistant]
Vault-Tec had their own Vault that may have been secret even to the Enclave.  It featured no experimentation and would have housed researchers and executives from the company; it's from this Vault that monitoring and All-Clear functions would likely have been performed if the Vault Experiments had been executed as planned.

Based on what we know, it seems like the War may have come sooner than anyone really expected, given the missed All-Clear signals and lack of feedback from Vault-Tec that many Vaults experienced.


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

[User]
[Wolfenstein] In 1946 why do Nazi soldiers wear power packs?

In the 1960s the soldiers don't seem to have any packs on them, but in 1946 the soldiers are wearing Tesla power packs on their backs. What are they powering?

[Assistant] Their armor. They are wearing very early prototype powered armor, which would later be scaled up into the Supersoldaten project. It's not a HUGE benefit to them, they aren't space marines or anythng, but every little bit helps.


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

[User]
If we only have 5 types of taste receptors, why can't we just mix various ratios of a few ingredients to make any flavor?

We can produce a very wide variety of colors to our eyes by only mixing red, green, and blue light. Why can't we do the same for food? For example, mix various ratios of salt, sugar, MSG, etc. to make any flavor?

[Assistant]
A lot of something's flavor is actually contributed by the olfactory receptors in your nose, which can detect hundreds of chemicals.  For instance, bananas have a flavor that is clearly more complex than sweet, salty, bitter, umami, and sour.  Turns out it's the isoamyl acetate in the banana stimulating your nose that contributes to the flavor of bananas.

Your olfactory receptors can pick up on hundreds of chemicals.  Smelling is half of flavor.  (Incidentally, this is why flavors are muted when you have a cold and your nose is clogged up.)

And for the record, chemists *do* use these aroma compounds to mix different flavors together.


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

[User]
ELI5: What does the computer do differently in its processing when a game is in full screen as opposed to borderless window?

I understand the difference between the two modes... but what is the computer doing differently? Does one mode allow the game to run faster or have different performance compared to the other?

[Assistant]
In fullscreen mode, the fullscreen application has "exclusive use" of a monitor, otherwise the OS has to manage all the displaying for that monitor.

Basically, when you run an application in a window, the OS has to "intercept" the drawing commands for each application that is running on that monitor, so that it can composite all of the drawings into their own little frames, and possibly do other fancy tricks. For example, on Windows 7/8 you can hover over the icon of an open application in the taskbar, and a small preview window pops up that displays what the application is drawing. The application doesn't handle this special case, it's all the OS's doing, and it can do this because it's intercepting the drawing of each application.

In fullscreen mode, all of this is bypassed. The application has full control over what is being displayed on the monitor. It controls when to refresh the frame, it controls the resolution that is being sent to the monitor, etc. This can have some performance benefits, since the OS will no longer be drawing anything onto that monitor, but those are minor compared to simply having complete control. In windows 8 for example, windowed applications have VSync force-enabled, since windows 8 will not draw a partially rendered frame into the application window. Although many people prefer VSync anyway since it eliminates tearing, it also introduces some input lag, which for some gamers is a big downside. G-Sync or other variable refresh rate solutions also cannot work in windowed mode because you can't force all other applications being drawn to match the refresh rate of a single application.


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

[User] [Warhammer 40k] If 50000 Orks crash landed in Saudi Arabia how would the rest of the world respond?

[Assistant]
Well, the US has a couple hundred nukes on alert, able to hit anywhere in the world in under an hour.

Assuming someone gets to the White House with a Codex quick enough, and the President and aforementioned Chairman of the Joint Nerds are able to convince the Russians and other nuclear powers of the seriousness of the threat, we might be okay.

Then we can deal with any sort of fallout from the nukes, which is probably safer anyway.


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

[User] ELI5: Why do men go bald as they get older but women don't?

[Assistant]
Genes code for proteins. Baldness is caused by a missing or malformed protein, caused by what we'll call the baldness allele. The version of the gene that makes the protein for hairiness can be the hairy allele.

If there's one copy of the hairy allele present, the recipe is there so the protein can be made properly and nobody goes bald. If there's no copy of the hairy allele, only the baldness one, you go bald.

Men have one X chromosome and one Y chromosome. Women have two X chromosomes. Each chromosome is made of multiple genes, each coding for different characteristics.

The primary gene for pattern baldness is on the X chromosome. Since the Y chromosome lacks an opposing gene (being significantly shorter), there's no way for the hairy allele to be on the Y chromosome. One copy of the baldness allele is enough to cause male pattern baldness.

Women *can* go bald, but they need two of the baldness allele (one on each X chromosome), so it's much rarer.


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

[User]
[Star Wars] Did Vader ever investigate or mention to Palpatine about the disappearance of Obi-wan's body when he tried to kill him

It seems odd for him to just brush it off when he's probably never seen anything like it happen from all the Jedi he's slain.

[Assistant]
Given the relationship of Sith master and apprentice, it sets up a dynamic where Vader would be incentivized to hold this information secret.  Simply report that he slew Obi Wan on the Death Star.

The moment would also have special significance to Vader.  There he was facing his old master, speaking about how the roles have changed.  At that moment, he also had to be thinking of how this was a step toward facing down his current master, the Emperor.  The combat against Obi Wan is like nothing he probably expected - a contest of wills more then lightsabers, ending in Obi Wan's seeming acceptance of his death with some vague threat about becoming more powerful?  What?  This might have thrown Vader in a tailspin about his eventual conflict with the Emperor.

Its interesting that when that conflict did come, it was Vader's turn to do the unexpected.  To also accept his death, but become more powerful (in a way) than the Emperor could have expected.

Also, what did happen to Obi Wan?  Neither being a visible specter nor whispering advice are in any way more powerful than a living Obi Wan was to Luke? A living Obi Wan could have been immensely influential in shaping Luke, and therefore the course of history?  What did happen to him?

I suspect he was able to join, at least for a time, with the force and shape events to aid Luke in ways a living Obi Wan could not.  The destruction of Alderaan probably impressed on him the stakes. It was Obi Wan who probably helped that torpedo turn 90 degrees down a port to blow up the Death Star.  Maybe Obi Wan influenced Han Solo to come back to help at that pivotal moment.  Maybe Obi Wan even helped Darth Vader to become possibly the sole survivor of the Death Star, as odd as that sounds.   Obi Wan, dead, may have been the big hero of Yavin, acting mostly through Luke.


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

[User]
[Star Wars prequels] so who came up with the battle droid idea anyway? Is there a galactic equivalent to sams club out there that they bought these things from in bulk? Like seriously man, those things are the cheapest things to put on the battlefield, one could easily just move them with the force.

And they have no apparent durability or strength. Sure theyre loyal to the cause but really? Who gave this idea the green light?

[Assistant] They were being deployed by the Trade Federation, which is just a shipping and trade conglomerate rather than a planet or nation. So they didn't have an actual loyal army of soldiers and used their money to buy the droids instead.


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

[User] Does moving water freeze at slower rate than stagnant water?

[Assistant] Yes! Freezing is a matter of removing energy, which could be either thermal (heat) energy or movement (kinetic) energy in this case. The more energy a water molecule has (warmer or moving), the more energy has to be removed before it will stay in one place (even tho the molecules are still actually vibrating a bit in the ice crystal structure!)


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

[User]
PhD Application without publication/thesis

I am an international student (South Korea) who recently graduated from Imperial College London MEng Chem Eng. Although I have graduated with Masters degree (it is an undergraduate degree, 4 years program), I got no publication or proper thesis.

I do have research experiences, doing UROP (undergraduate research opportunities programme) at Imperial College, but I am not sure if this would be a strong appeal.

After this I wanted to apply to top US universities for PhD, but I was concerned whether I would be a strong candidate or not, so currently I am thinking of applying to MS as well. I got good GPA grades, but only got 2 letters of recommendation from academia, and 1 from non-academia. So my major concerns are:

1. No publication/thesis
2. Letter of recommendation, 1 from non-academia
3. Haven't directly contacted to any professor for PhD availability yet

Would I have a chance to make it to top uni's PhD?

[Assistant] Many many people are accepted to PhD programs without publications, maybe more than 50% of candidates. Perhaps in top 5 worldwide Unis may be slightly lower proportion but most would be fine. Grades, experience, passion, and good communication will help your application a lot more.


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

[User]
[Star Wars] Can someone tell me why it was not possible for Mace Windu to survive?

His arm got hand got cut off, big deal, anakin loses his arms many times, Luke gets his cut off too, its almost a non-factor the movies paint it out. He gets blasted with Force Lightning, but Luke did too, and Luke endured a lot longer.

My only gripe with the scene is he's flung out the window. I'd expect a Jedi Master to someone gain control, use the flying cars and land on one of them using the force or something. I'm not saying every character death has to be on-screen, I'm just curious as to why anyone would be so sure that a Jedi Master would die merely from losing his hand and getting thrown out the window with force lightning.

We've seen Anakin survive Mustafar. We've seen Maul survive getting sliced in half. Why not Mace?

[Assistant] Because all of those things happened individually to those in question. They happened simultaneously to Mace, and he kept arcing with lightning until we couldn't see him anymore because he was so far away.


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

[User]
Why do dogs want food so much? Do they have a limit?

In nature, animals eat freely. Why do we have to treat (some) dogs differently by only feeding them a specific amount? My dog always acts starving when I'm preparing anything in the kitchen. What would it do to a dog if it had the option to eat freely?

[Assistant] Yes, in nature animals eat freely, but they don't have access to food whenever they want.  They have to go get it and that takes a lot of work.  It's best to be programmed to eat whenever you have the chance because who knows when the next one will be.  If you were to have a constantly available source of food available there is a good chance your animal will become overweight.  That is certainly not true of all pets as the physical activity it gets is a factor.


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

[User]
ELI5 why there is a limit on growing?

Why can't humans/plants/animals grow further than what they usually grow to?

[Assistant]
Well, bad things start happening when parts of your growth become uncontrolled.
Acromegaly and gigantism are both health conditions which result from your growth hormones essentially never turning off. This leads to all sorts of weird and bad consequences such as heart failure, kidney failure, severe headache, increased odds of infection and metabolic disorders, skeletal problems, etc. To be fair, some of these results are just because too much growth hormone can do some weird shit to your body. However, a lot of them, such as the issues with the skeletal system and circulatory system, are simply because that level of growth causes problems such as thickening of the heart wall, or simple inability of the body to support something that damn BIG.

If you are wondering "well, what if we just fixed all of those problems? Then what?" This brings us to another thing, the square-cube law. Essentially, when you scale things up proportionally, the volume is proportional to the cube of the original volume, while the surface area is proportional to the square of the original volume. In more simple terms, when you make things bigger, the muscles and bones are relatively weaker compared to the sheer bulk of the animal. This is why, when you look at the skeleton of an elephant, it doesn't just look like a scaled-up mouse: the bones must be much more thicker in comparison to the overall size in order to support its mass. (Google "allometry" for a more in-depth explanation.)

So, essentially, in order to get healthy, viable 'giant' versions of humans (or any other animal), you would need to make drastic changes to their basic anatomy in order to even ensure that they would survive.

(Side note: this is why you will never see ants the size of skyscrapers. Also, underwater animals have an easier time coping with this because the buoyancy of water somewhat negates the effect of gravity. This is why you can see incredibly large underwater animals such as blue whales.)


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

[User] [Harry Potter] How would the wizarding world handle address the situation of a notable child in the Muggle world such as Prince George being a wizard and developing magical abilities? Both now and in the long term as they grow into adulthood and their future highly visible role in the Muggle world?

[Assistant]
Most likely the royal family will resist MoM influence, so the MoM will need to confundus the royal family and take the young prince. Maybe have a spell that everyone accepts he goes off to a boarding school and doesn't participate in public life.

There are precedents of unwilling families, the Dursley for one. But an unschooled magic kid is too much danger for both the muggle and magical worlds. Clearly this would be under MoM mandate.


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

[User]
[Frozen] Why don't any of the soldiers have guns?

Canonically, the story takes place in the 1840s, so the guards and soldiers should have access to firearms. However, they are stuck with swords and crossbows. It's not like there's a lack of gunpowder, either, since you can see gun ports for cannons on several of the ships in the fjord.

While the out-of-universe explanation is obvious, can someone give an in-universe explanation for this situation?

[Assistant] Given the country's geography and peaceful foreign relations, the threat of overland foreign invasion is minimal, so the guards mainly enforce laws and perform ceremonial duties. There hasn't been a need to modernize the armory. The military leaders believe that learning to use traditional weapons instills discipline and builds character. Guns look too easy to use--you just pick them and pull the trigger--and that doesn't teach proper respect for what it means to carry around something lethal.


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

[User] ELI5 : Why does travelling make you feel so tired when you've just sat there for hours doing nothing?

[Assistant] Former flight medic here. There is lots of data on the "stressors of flight" (many of these stressors are also present in automobiles). As the vehicle moves, the sway and direction change cause you  to have to keep yourself upright. These micro movements cause your muscles to be continuously working (even if you don't realize it). The US Air Force has done studies report conistent exposure to aircraft vibrations can lead to fatuige and increased chance of health problems.


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

[User]
[MARVEL] Superhuman Registration Act: Did superheroes have to unmask themselves to the government only? Or was it public knowledge who these people are?

My friend thinks that those unmasked had privacy from the public. I thought the issue was that the world would know who these people are?

[Assistant]
Unless the information were classified, a Freedom of Information Act request would provide it.  Even if it were classified, 'anonymous sources' would probably be sufficient for the press to find out, and the the information would no doubt be valuable -- think TMZ for the Cape and Cowl crowd.

On the other side, for the Cape, if only the government knows, then they still have to go through all the effort of preserving a secret that is no longer secret - all the while their family and friends could be compromised by any of the host of villains skilled at espionage.  Why not go full public, like the Fantastic Four, plus get the benefit that now your family and friends know and can protective steps. Even better, those loved ones should be eligible for government provided security, such as the Guardsmen, who are basically Iron Man Lite.


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

[User]
Could Identical Twins Have Identical Children?

Ok so this has actually been a curiosity of mine but I've never gotten a good explanation.  Here's the Scenario:  Lets say you have 2 sets of Twins.  Twins A are both male and identical, Twins B are both female and identical.  Lets say Hypothetically Twins A and B meet get married and both each have a kid (Child C and Child D).  Would Child C and Child D be identical even though they have different biological parents who are identical?

And purely hypothetical, if Child C was a female and Child D was a male and they had kids could they produce dopplegangers of their parents?  This is just something I was wondering, could anyone give me an explanation as to whether or not this could be possible?

[Assistant] Children of two pairs of identical twins (or one pair with the same partner) are genetically equivalent to siblings of a single couple, and as such would be no more or less likely to be identical than any two full siblings.  Such an event would be so staggeringly unlikely that even if humans spread out to every planet in the galaxy, and every galaxy in the cosmos, and breed like rabbits until the heat death of the universe, it will still never happen.


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

[User]
[X Men] Why should I send my son to Xavier's academy (details inside)?

So throughout his time in school, my son (a great linebacker) amazingly hid his abilities as a mutant; that is until the recruiting camps. He was a well sought 3 start prospect, but then he decided to come out of his shell.

The scouts watched him run a 3.3 and max at 1150 lbs. After that the door was knocking all the time and all the anti mutant neighbors are being friendly.

Today professor Xavier will be visiting my son and me to tell us about his school. However we've been told by coaches Saban, Miles, Mora, and others that if my son goes to his school, he will never play in the NFL.

What are the consequences if he chooses to commit to an sec school?

[Assistant] So here's the deal, those schools only want your son for his abilities, same as Xavier. The problem is antimutant rules for professional sports is unofficially in place and official regulations are right around the corner. The NCAA will follow shortly, they have to. Once that happens your son is SOL, if he isn't valuable to the school you can kiss that scholarship good bye, and he wouldn't be much better in a mutant league since it sounds like he has low level super strength at best and he'd be playing against guys who can throw trucks around. At least at Xaviers he won't have to worry about his scholarship going away, and he won't get put on any of the teams that get into real danger. Its not glamorous, but at least he's guaranteed an education.


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

[User]
CMV: People in neutral stances shouldn't be demonized or be instantly thought of as siding an enemy or the opposite side

So something happened that really pushed something in me and I wanna hear the arguments and side of the people who believe in the opposite argument.

So an event of relative great turmoil is currently happening in my country (aside from the current worldwide crisis) and it's really riled up the populace right now. A fe wof the readers coming from the same coutnry as me might instantly recognize what it is, but as of now I am not revealing where it is for the purposes of safety and such.

So my stance is that people who choose not to side to any argument and such shouldn't instantly be thought of as siding the enemy or opposition. For many  years, I was never swayed or moved to any sort of political party or ideology and didn't wanna meddle in politics or governmental affairs. Of course, after several events I've changed from that and have come to challenge the current status quo since it's just so fucking atrocious. The way the government here is running is just wrong.

However, I'm seeing people end friendships and fight here and there just because that person doesn't share their view and just wants to be in peace and not meddle in anything. Now, I've been in that position before albeit during a different time. I can symphatize and emphatize with the people who just suddenly lost their friends just because they didn't want to mess with the Big People. And I find that horrendous and illogical. It's liked they were whipped into a frenzy to think everyone who doesn't follow their view is wrong.

That's why I've always thought of people in the middle or in  neutral stances as resources that a faction can obtain by educating or informing them about a crisis or a situation, giving the actions or details of their side, and then voila, you got yourself a new member who believes the same thing you do. By just alienating or outright demonizing them just makes them less and less likely to go to your side. If they find that the other side is the same, then they're belief is further reinforced while on the other hand if the other side explains and convinces them, well that's a resource gained by the other side.

What I'm saying is, people in the middle need convincing, they need to know and throw off that pesky shadow of ignorance from their minds. If they won't budge, then leave them alone. Yeah your respect for them will change, but that person is someone who you might've shared a lot of moments with, who you enjoyed the company of for many years, and you're throwing it down the drain just because they don't wanna mess with something that they're not sure might end well. If they were convinced by you then congrats! You have a new person on your side. If they aren't, okay then, I won't bother you. You are informed about the current situation and yet chose not to meddle because you fear the reprecussions. That's fine. No relationship-ending necessary.

Right now, my country's in a lot of turmoil and a lot of people are angry, but that doesn't mean that those in the middle should be in your crossfires as well. They're civilians in the middle of a war between two countries. And when the two sides clash, they'll be in the way and get hurt.

I just want to hear what people who think otherwise want to say. I want to know why exactly are the people in the middle the same as the opposition. Why are they the enemies as well? What is it about the people with a neutral stance that makes you think they side the opposition as well?

EDIT: Would like to clarify, I am redefining the term 'neutral' here as 'people who choose not to join or pick a side or argument because of various reasons ranging from ignorance to self-preservation'.

Alright, I finally see where the side of 'people not taking a stand is siding the opposition' is coming from. But I reserve my view that 'neutrality' is not a single categorical term that can encompass everyone under it. Not everyone is on the same level of neutrality and can have valid reasons of why they aren't joining in, whether because they're afraid, their lives are on the line, or because they haven't been taught or convinced enough. Those who stay put just because they think nothing is wrong or because they completely agree with an unfair status quo are the ones who are truly on the side of the opposition.

UPDATE: Holy cow! I never realized it would blow up this big this quick. And whoever gave me Gold, thanks man!

[Assistant]
When the Nazi party took unilateral control of Germany in 1933, the party had approximately 2 million members, or ~2.5% of the German population.

At the time of the rise of one of the most brutal totalitarian governments in human history, the perpetrators were outnumbered by a margin of nearly 40 to 1.

Many remained 'neutral' - failing to resist because they were ignorant or afraid. Neither reason made even an iota of difference to the 11 million people that the party murdered.

Over the following decade, 5.5 million more Germans joined the party. Many joined out of the same ignorance and fear, for social or financial standing, or simply out of a need for belonging. Most had little interest in genocide.

Today, we have a name for these people. We call them Nazis.

In practice, neutrality is often functionally indistinguishable from siding with those in power.


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

[User]
[40K] Has any species tried travelling beyond the Milky Way?

I know the Tyranids are extra-galactic invaders but surely the Eldar tried at some point, or the Imperium did?

[Assistant]
Not really, actually, outside the Tyranids.  The Eldar have used the Webway since the Old Ones created it.  And the Old Ones, well, they turned to energy before leaving the galaxy.  So, no, no one outside the Tyranids have tried leaving the Galaxy...

Unless the rumors of Magos Kotov's fleet are true.


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

[User]
ELI5: How do windows on the ISS and other spacecraft not fog up?

Since it is extremely cold in outer space, moisture in the air inside a spacecraft should condensate on the inside of the windows. How is this prevented?

[Assistant]
Condensation on your windows occurs because the heat from inside transfers to the outside through the glass, thus creating cold air right on the glass layer which causes the water to condensate out.

It's cold in space (when in shadows, otherwise it's actually really hot), but there is a very limited ability for heat to transfer in space. Heat transfers through conduction (touching something that has a lot of heat), convection (fluid currents carrying heat), or radiation. Heat from inside the ISS can only transfer to space outside via radiation. And radiative heat transfer tends to be very small unless the absolute temperatures involved are very large.


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

[User]
How do ant traits non queen members evolve?

For example, how did worker ants get larger mandibles if they themselves cannot reproduce?

[Assistant] The mutation would be with the queen, and would be passed onto her daughters. A colony whose queen had a beneficial mutation would be more likely to thrive and out-compete other colonies, and thus more likely to pass the mutation on.


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

[User] [My Hero Academia] What Is Warfare Like? How has doctrine and strategy changed with superheroes now? Are they more elite units now, not just standard soldiers?

[Assistant] Weapons still kinda work, and most people don't have All-might level quirks. In fact combat application effectiveness is pretty rare which is why they have trained heroes in the first place. Being a crackshot will still kill most people in that world. So uh, strategic use of powers probably?


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

[User] [MCU] Why was Thor briefly unable to call Mjolnir to him after falling out the helicarrier in The Avengers?

[Assistant]
[SPOILERS!]

It's possible that he hadn't properly called it yet out of hesitation.  He began raise his hand of habit, but stopped just short of actually calling for Mjolnir.

Thor had just found out that Loki orchestrated a very effective attack on Earth's forces.  He started by making himself seen infront of a large crowd, letting himself get captured so he could be in the right place at the right time.  His troops flew unchallenged to the helicarrier, nearly destroying it and everyone onboard.  Hulk was unleashed, and everyone else was busy trying to keep the helicarrier from crashing.  Thor was tricked by his brother yet again, trapped in a cage and forced to watch helplessly as Agent Coleson was mortally wounded trying to stop Loki.  He was then dropped from high altitude in the same cage that had held his brother only minutes before.

Thor was questioning his own worthiness.  He screwed up bad, and everyone else was paying the price.  Even if he wasn't worthy in his own eyes, he needed to make things right the best he could.  When he finally did call to Mjolnir, it came.  In his father's eyes, he was still worthy.


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

[User] ELI5: How do prosthetic hands of amputees who were born without, or lost their hands know which finger to move?

[Assistant]
It's two different cases.

If you have a hand and lose it, you have all this neural hardware that no longer works.  With the prosthetic it's a matter of transferring that structure to a new outlet.

If you've never had one, then you have to build the ability from scratch.

Either way, it's many weeks of difficult physical therapy, just like a baby learning to control its hand, lots and lots of reps are needed.


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

[User]
Best practices to avoiding impropriety?

As a woman in science, especially in the current #metoo era, I've always been acutely aware of men being sexually inappropriate with me (which has happened many times, both inside and outside professional settings). However, as my career has advanced and I've gained more power, I realize that now I'm in a very different position, one where I could conceivably be the person in power if a sexually inappropriate thing happened. It feels weird.

I work in a large, friendly, sometimes raucous research group; I have young men and women mentees who I directly supervise. Our group generally gets together socially once a week or so, often with alcohol and other disinhibitors involved.

I'm wondering, what is my, and any other mentor's, obligation in such a situation? Should we recuse ourselves from socializing with mentees (eg no PI/postdoc, or postdoc/grad student, or grad student/undergrad socializing)? Am I overthinking all of this and as long as no one goes home with anyone it's all gravy? If a mentee makes a flirty statement, is it enough to roll your eyes and change the subject, or as the person in a position of power, do we (I) have an obligation to say, "hey man, let's keep it all above board"?

Other thoughts on the topic - how do we keep a cordial, collegial environment without crossing any lines?

[Assistant]
I think you can model collegial socialization by drinking moderately and behaving well.

It would be a kindness to shut down impropriety. Let mentees know that it's not only unwanted, but unprofessional.


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

[User] ELI5: What is the difference between insulating a house and double wall insulation in thermos bottles? Couldn't using that technology conserve energy?

[Assistant] Both are the same technology, still air conducts not really well. The problem with making your house as insulated as a thermos bottle is that the thermos bottle contents is sealed, there is no ventilation. This works for coffee, but not for humans.


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

[User]
ELI5:Why and how do sideways sails work?

While this is a stupid question I can't understand how does a sideway sail on a boat/ship move the ship forward, instead of to the side.

[Assistant]
A sail is a lifting body, like a wing. As long as the sail is in the right position it will generate lift; or create lower air pressure on the outside of the sail than the inside. When this happens the sail will, like an airplane wing, move towards the low pressure side. This creates movement, just like it does in an airplane.

The reason the sailboat moves forward instead of moving towards the lifting side of the sail is that the sail is connected to the boat, and the boat is in water, and the water has much more resistance than the air. So, the shape of the hull transfers the lifting force of the sail and turns it into forward motion.

So, a sail is basically an airplane wing that's vertical instead of horizontal, and the sailboat hull is the tool that transforms the sideways pull of the sail into forward motion.


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

[User] Why does a can of compressed air get ice cold when used?

[Assistant] In the can, the compressed air is in the form of liquid at very high pressure. When you squeeze the trigger the pressure drops and the liquid boils into gas. That phase transition requires energy, which it pulls from the surrounding air (via the can). That causes a corresponding temperature drop of the can as heat is pulled out of it. In essence a compressed air can is really an evaporative cooler.


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

[User]
[Spongebob] Why are the squids the cultured ones?

Why in bikini bottom does it seem all the higher forms of culture and art are owned and created by the squids? Not just squidward but it seems every time there is a nice concert or art event going on its almost 100% squid in attendance.

[Assistant]
Squidward is actually an octopus.

Octopi have some of the largest brains, most complex nervous systems, and well-developed senses in the oceans, giving them a highly-refined sense of aesthetics.  Their biology allows them to appreciate art *more*.


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

[User] ELI5: Why is marijuana illegal in the first place?

[Assistant]
It's best viewed in the context of the Temperance movement, which was a worldwide movement  against intoxicants which degrade man's ability to think and act rationally.

The movement became politically influential in the 1860s, and the advent of WW1 created command and control economies with unprecedented governmental powers.  These powers combined with popular opinion created the regulation and outright banning of alcohol in many jurisdictions, particularly those influenced by Western thought, and other intoxicants were similarly judged and outlawed - any resistance to the loss of these recreational drugs were minimal compared to that of alcohol.  A second, and related movement crusaded to ban opium, probably the most banned drug in the world, which met with greater worldwide success than prohibition against alcohol. The emergence of highly addictive and cheap processed or synthetic drugs such as heroin or cocaine further encouraged a worldwide ban on certain drugs, which gave a legislative framework for both local, national, and worldwide illegalization of drugs.  Marijuana was banned at approximately the same time alcohol, opiates, narcotics and more were banned, and for the same reason.  Tobacco as well became strictly regulated although not altogether banned.

Dominance of Western nations ensured that other nations followed suit to bow to political pressure, as the drug trade was international.


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

[User] ELI5: Why are cavities so damaging and permanent despite advancements in modern medicine?

[Assistant]
They're not...infections due to cavities and lost teeth used to be a huuuuge health problem. Now, thanks to modern medicine, it's just annoying.

Cavities are permanent because you don't regrow enamel...it's not like bone, it can't heal. But once you have a cavity, modern dental techniques can detect it, remove the damage, and fill the cavity as a routine procedure. Properly done, it's basically a permanent fix.


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

[User] ELI5:why does it sound different when cold water is flowing out of the faucet than when the water is hot?

[Assistant]
Normally, a water heater has a lot of piping. Pushing the water through this extra piping takes pressure away from the water.

So the water is pushed out of the tap with less force, so the sounds it makes is different.

In addition, heated water often has air bubbles in it. You can see this because they make the water slightly cloudy. Air bubbles absorb sound and allow the water/gas mix to compress or expand slightly. This also changes how the tap sounds.


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

[User] ELI5: the difference between general anaesthesia, a medically indjced coma, and a coma caused by a traumatic brain injury, aside from the fact that doctors induce the first two and can easily reverse them. Is there anything different going on in your body/mind while in these States?

[Assistant]
The difference between and induced coma and general anesthesia is time and reason. General anasthesia is short and used to provide safety and comfort during surgery, where an induced coma is longer and used to slow the metabolism of the brain for an extended time to prevent excessive swelling that can cause more permanent damage.

A coma from injury occurss when certain parts of the brain are damaged. A person may come out of a coma if those parts can be healed, but they may still have permanent damages that last after they wake up.


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

[User]
[Spider-Man: No Way Home spoilers] So for the first credits scene

How exactly was Eddie Brock/Venom brought to the MCU? I haven't seen Venom or the sequel, but AFAIK, there isn't a Spider-Man in there. At least, not yet (though I don't know why they'd make *another* as opposed to using Holland or Garfield).

Point being, the spell works on bringing in everyone who knew Peter Parker was Spider-Man, correct? So how would Eddie Brock/*this* Venom fit the bill? He clearly didn't recognise Spider-Man by name, as he told the bartender he'd have to go meet "this Spider-Man" in New York, shortly before he got booted back to his universe.

Maybe I've gotten the spell specifics wrong. After all, I don't recall Max/Electro finding out that Spider-Man is Peter Parker (I may have forgotten that).

[Assistant] In the Venom 2 credits Venom is telling Eddie that symbiotes have a hive memory beyond his human understanding. At that moment he is yanked into the MCU dimension by strange's spell. The implication is that though this Eddie didn't know Peter, the symbiotes all do know him on some hive level.


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

[User]
How large does building has to be so the curvature of the earth has to be considered in its design?

I know that for small things like a house we can just consider the earth flat and it is all good. But how the curvature of the earth influences bigger things like stadiums, roads and so on?

[Assistant]
Definitely for the Large Hadron Collider and similar insanely large particle accelerators or that laser-bouncing tunnel for detecting gravity waves. Not just because they are huge but because their operation relies on incredible precision.

IIRC the LHC had to account for how the moon's gravitational pull moves Switzerland/France and if the bedrock under the east side moves slightly more than the bedrock under the west side then the beam will be out of alignment.


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

[User]
ELI5 - Why do we have moles on our skin?

And why do some people have more than others?

[Assistant]
1. Natural carcinogens in the environment (e.g. UV from the sun) cause mutations in your skin cells.
2. Some of these mutations cause those cells to grow unnaturally crazy (think first steps of cancer).
3. In built defense mechanisms steps in and detects abnormal growth or messed up genome that cannot be easily fixed.
4. Cell decides to self-destruct.
5. Results in a mole.

This is a good thing. Following the logic, tendency to form moles means you're less susceptible to melanoma.


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

[User] What was the beef between Sartre and Camus? Weren't they like best friends at one point?

[Assistant] They were. But Sartre backed the USSR even with the atrocities we knew were being committed, and Camus, while sporting Communist sympathies couldnt stand by Sartre while he was willfully blind to the crimes the USSR was committing. They wrote a pair of scathing articles, Camus indirectly toward Sartre and Sartres specifically at Camus.


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

[User]
How do CPU and gpu architecture differ?

I'm reading this book "Inside the Machine" and its been really good at explaining how CPU architecture works. So I'm wondering what differences exist in a gpu that allow it to perform calculations much faster. Mainly interested because my uncle works at Walmart and hes always telling me how he uses multi-gpu systems to run large data decryption and security stuff (I don't fully understand what he does with the gpu system) but I'd like to know more about how this is possible so I can follow the conversation easier. I'm reading other books on the security things he does to follow that also :)

[Assistant]
It doesn't do any single operation *faster*, but it does more at a time.  A typical desktop these days has a quad-core CPU, but a high end GPU could have 512 "cores."  The difference between CPU cores and GPU cores is that in a CPU each of its cores could be working on a totally different program, and each of those CPU cores has a lot of features that makes running a single program really fast.

In a GPU, you have big clusters of cores that have to run the same program together, but on different pieces of data.  This makes sense because in graphics you want to do the same program (draw a triangle on the screen) on lots of different data (lots of different triangles).  There are other types of problems that also map well to this kind of architecture.  This is called SIMD.  In addition, these GPU cores don't have the same features that make each individual CPU cores super fast, and so each individual GPU cores is actually kinda slow on its own.

So in summary, GPUs are fast because they have lots of "cores," but these cores have to group up to execute the same program on a variety of data (SIMD), so you can't just use a GPU as a CPU replacement.  CPUs, on the other hand, are extremely good at running a single thread of execution super fast, and that's why we use them as the main processors of our computers, and not GPUs.


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

[User]
[DC] Would the Joker have any issues killing a Joker from another dimension?

Some dimensional rift thing happens. Would he have any qualms murdering a different version of himself?

[Assistant]
They'd be absolute besties until one laughed wrong at the wrong joke, and it would still be on the surface completely fine, but they would rapidly go into legendary levels of resentment, and sooner rather than later both would start planning to kill the other, and watching each other with rapidly escalating paranoia.

The moment whatever lunatic plan works and the multiple Jokers get Batman in a position to murder him (and a Sinister Six of Jokers would absolutely get him in that position), at least one of the Jokers if not multiple would immediately try to murder the other Jokers, because who the fuck do *they* think *they* are, to get in the way of *my* dealing with Batman?


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

[User] ELI5: how do they film scenes in movies that happen in front of a mirror so that the camera can't be seen?

[Assistant] They film it from a slight angle, or they remove the camera from the reflection in post production. The other option is not having a mirror at all. The scene in Terminator 2 when Linda Hamilton is working on Arnold's cybernetics in his head was filmed using a prop head (in the main shot) and Linda's twin sister with Arnold in a "mirrored" room built behind the mirror.


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

[User] ELI5: If the liver filters out toxins from the animal's body, then why does it contain such nutritional value for carnivores and is typically what the eat first?

[Assistant] The liver does a lot of things. There are lots of biochemical reactions you need to survive which takes place in the liver. The liver does not actually filter out toxins but it changes it to other less toxic chemicals that can either be metabolized or filtered out by the kidneys. But this is just a small part of the biochemical reactions taking place. The liver produce proteins, a lot of the hormones, bile, insulin, etc. A lot of these biochemical processes is what actually requires the vitamins and minerals you need so the liver is where you find the biggest concentrations of these.


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

[User]
What does the recent research into T cells and cross immunity of COVID mean?

I am seeing lots of information regarding this, if you have caught another similar corona virus in the past even if you dont have antibodies you may have T cells or memory cells that may produce a milder case of covid, from my understanding.

Would this also be true if you were to later contract a mutated strain of Covid? What are the implications of this, in regards to immunity - does this mean that its possible that once more people get covid that at some point it may become like the common cold?

[Assistant] We don't even know to what extent T-cells or antibodies from previous SARS-CoV-2 infection prevents future infection, much less cross-reactive antibodies or T-cells. Previous evidence suggests the damage caused by this sort of coronavirus is mitigated by T-cells, and there's evidence more T-cell production is associated with a less severe disease course in COVID-19 patients, but that's it. That relationship may simply be a correlation. It could be that the immune response to SARS-CoV-2 is protective and that the response derived from previous coronavirus infections is harmful. We will have to wait for better studies. Most likely this will require prospective recruitment and monitoring, which is difficult and costly, but some work like this is ongoing.


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

[User] ELI5- Why do Cuban-Americans actively lobby against US-Cuba relations?

[Assistant]
Most of them are from the population which was forced to flee or expelled from Cuba when Fidel Castro took over, or have since escaped.

Their big thing is that it is still the Castro's in charge of a still very much communist and unitary political party system of government.


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

[User]
ELI5: Why does snow leave my car so dirty?

You'd of thought that it would clean it if anything?

[Assistant]
Are you talking about driving around in a place like New England during the winter? If so it's not the snow that makes your car dirty - its mostly the salt they lay down and some crud on the road. The road is wet and very briney during/after a snow storm in an area that salts because the salt melts the snow, so as you and other cars drive around the tires throw it into the air and it sticks to your car.

So while salt is the most of it there is also dirt and stuff being flung up too.  There are people who keep their cars highly detailed that won't drive when it rains for this reason, even in summer.


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

[User] [Star Wars] Why did Qui-Gon and co. not just hire someone to take them off Tattoine instead of go through the pod-race shenanigans to get the hyperdrive parts they needed?

[Assistant] As seen in *A New Hope* and *The Gunslinger* (*The Mandalorian*), Tatooine is a cesspool of backstabbing scum who serve the highest bidder, and their mission required an extreme low-profile. Two Jedi, a Queen and her escorts are a gigantic beacon of attention, that's why some of them stayed on the ship. Better not to trust any Tatooine resident for a long period of time and just deal with them in order to get the parts they need (keeping in mind that they weren't planning on going through the pod-racing hassle in the first place).


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

[User]
[Dune] What sort of propulsion were spacecraft using prior to the discovery of Arrakis?

Arrakis is the only planet on which one can harvest spice melange, which allows for the bending of space, thus permitting intergalactic travel. But before the planet was discovered, how were people crossing the light-milennia beween galaxies?

[Assistant] The Navigators aren't folding space, they're just... navigating. The ships use something called the Holtzman effect to travel, but the calculations necessary to guide the ship safely are impossibly complicated. The first starships just used computers, but since the Butlerian Jihad that's not an option. Guild Navigators obviate the need for calculations by being prescient, and are actually an improvement over the computers.


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

[User] If electrically charged particles were fired into a black hole, what would happen? Would there be a point at which the electro-static repulsion of the particles overcame the force of gravity?

[Assistant]
If you send charged particles into a black hole the black hole becomes charged, and yes, there is a point where the electrostatic repulsion wins over the gravitational attraction.

This happens when (in the right units) the total charge equals the mass of the BH, in which case it is called an extremal black hole. If the charge is less it's a stable subextremal BH, if it's more then it would be a superextremal BH, actually an unstable state.

However, by sending charges into a normal subextremal black hole it is impossible to make it overcome the extremal barrier. If a particle carries a charge that would make the BH superextremal, then the electrostatic repulsion prevents the charge from falling into the black hole.


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

[User]
Eli5 Why do some apps stay open when you leave for 5 seconds but others take you back all the way to the starting screen?

Edit: Inspiration came from the Minecraft and Roblox app lol.

[Assistant]
Imagine that apps are litte robots in your phone. They are all asleep in little bunk beds. When you launch an app, its robot wakes up and starts talking to you.

When you switch to a new app, the old apps robot now has nothing to do. On big phones, there could be room for two app robots to be awake at the same time.  On small phones, theres only enough room for one robot at a time, so the old robot goes back to its bunk bed and goes to sleep.  Even on a big phone, the robot might get bored with no one to talk to and put itself to bed.

When you launch the old app again, its robot wakes up, but its forgotten everything it was doing so it has to start all over from the beginning.

But smart robot makers know this makes users sad!  They give their robots a litte notebook, so when they go to sleep they can write down everything they were doing.  That way, when they wake up, they can look at the notebook and remember just what to do to pick up where they left off.

It is a little more trouble for the robot maker to teach the robot how to use a notebook, but its so much nicer for everyone if they do.