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

[User] [Mrs Doubtfire] It would take a team of makeup artists several hours to transform a middle aged man into an old woman, yet Daniel Hillards brother found a technique to do it in minutes. Why hasn't he used his mastery of makeup to become the most successful makeup artist on the planet?

[Assistant]
The best person in any field is not necessarily the most talented. They're just the best person actually *in* that field. The most talented person may never have encountered it at all, or realized how good they are.

Like, the most talented swordsman of our generation will probably never even pick up a sword.


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

[User]
Can two objects orbit each other because of Coulomb's law?

Both Newton's universal law of gravitation and Coulomb's law are inverse square laws, so is this possible?

[Assistant]
According to the simple inverse square laws: yes, absolutely.  They are mathematically governed the same (just with different constants) and so orbits should be possible in both.

Classically speaking, this is what we believed, and indeed it is a good approximation of the truth for nonrelativistic speeds.

Relativity puts a dent in the classical picture though, and both gravitational and electric orbits actually emit waves due to the accelerating reference frames that cause them to lose energy and spiral inwards.

This effect is usually quite small for gravity.

Of course, quantum mechanics also puts a dent in the classical picture, so if we are talking about a proton and an electron then quantum mechanical effects would dominate and no it wouldn't make sense to describe the electron as orbiting the proton.


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

[User]
[Equilibrium] Can a cleric call out sick if he doesn't "feel good"?

I mean, at what level does physical discomfort cross over into emotional discomfort. I know that I always say "I wish I was dead" when I have a cold.

[Assistant]
Pain is a physical sensation; suffering is the emotional experience of that sensation. It's very likely that everyone on Librium has a heightened tolerance for pain simply because that pain doesn't distress them.

But the state is all about efficiency. There are probably very cut and dry rules about when you should call in sick, simply because your performance will be sub-optimal, and getting others sick will result in them performing sub-optimally.

The same would apply to injuries. If a Cleric twists his knee and just keeps pushing through the pain, doing more and more damage, eventually he will be mechanically incapable of doing his job, and that results in a lost asset for the state.


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

[User]
[Rick and Morty] If some aliens managed to create an Immortality Field around a holiday resort, why can't Rick create miniaturised immortality fields for himself and his family?

Seems like a good safety measure to ensure Rick and his family don't die so easily. Of course the thrill of potential death must keep things from getting boring, but surely at times it'd be good to know if Rick or the Smiths are in mortal danger that there's something protecting them, right? And the science shouldn't be an issue, given that Rick can do practically anything from turning a black hole into a star to creating a microverse battery. So really miniaturising existing tech shouldn't be too tricky for Rick.

[Assistant]
Assuming there aren't properties unique to the resort's locale preventing such replication, Rick could easily do that.

But why would he, at this point? Here is a man who continues to put his grandchildren in danger, emotionally manipulate his daughter, and existentially shit all over the human paraquat known as Jerry Smith - all of which is motivated by Rick's selfish desires. He has probably thought about it and concluded, superficially, that it would be too boring, and would artifically impose a control group onto the chaotic lives of ultimately meaningless people who would somehow allow the tech to fall into the wrong hands anyway.

But with Rick Sanchez, there is likely a darker reason: He would have to actually love his family enough to give it a try. Why couldn't he make the tech tamper proof? Or work only for his family member's unique DNA and universe "signature?" Rick spends his free time turning himself into goddamn pickles to both prove his intellect and satisfy risk-seeking behavior born of self-loathing, so if he won't even use such immortality tech on himself, then his family are simply not part of the equation. He would have to learn to love himself first in order to love others, even those closest to him, biologically and culturally.


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

[User]
ELI5: Why were dinosaurs so much larger than animals today?

Was it because there was a lot more oxygen in the atmosphere?

[Assistant]
One of the theories was due to the higher levels of carbon dioxide in the air. Plants in carbon rich environments grow very well but actually have less nutrients then if they grew in an environment similar to what we have today. So animals needed to eat a lot of plants just to get enough energy to survive. They developed larger stomachs to handle more food and grew bigger to carry a bigger stomach.

Some Sauropods maxed out the food eating stat and are basically walking stomachs, they have a long neck so they can eat everything in front of them in a large swath without having to walk anywhere. Moving that much mass requires a lot of energy so they stand still and swing their necks around eating everything they can reach. When all the food is gone they just take a few steps and now they can reach a ton of new food.

With plant eating dinosaurs getting bigger, the carnivores needed to get bigger to be able to take them down. You needed to be big to kill a giant dinosaur, but if you did, there was more than enough meet in one kill to sustain a heard of carnivores.

End result, everything keeps getting bigger and bigger.


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

[User] Pilot wave theory, a theory involving highly complex and non-linear differential equations, is fully equivalent to matrix mechanics, a theory involving only linear differential equations. Does this have implications for our ability to solve non-linear differential equations?

[Assistant]
Matrix mechanics is contained in pilot wave theory. Pilot wave theory just adds an equation describing trajectories which is non-linear.

It has no implications at all on our ability to solve non-linear equations.


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

[User]
[The Culture] Do the Culture have a ground force?

Question in the title basically. Do they have access to ground troops (or have any need to?)

[Assistant] Every (combat) drone is a potential ground trooper. There's no real difference for them in hovering in space, a ship or in the atmosphere. They have a lot of drones from what I've read. SC agents have weapons which can usually take on whole armies of those underdeveloped species they ~~manipulate~~ help. With ships and weapons of such precision and power ground troops would be pretty much unnecessary in all out conflict though as you could do everything from orbit I'd think.


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

[User] [Marvel] So here I am, sitting at home watching the invasion of aliens and all of a sudden the norse God Thor turns up. It's pretty apparent with now real life proof that I need to start worshiping this dude, right? Also is Neil Gaiman's Norse Mythology reliable scripture?

[Assistant]
Thor does not care for your worship, would not know, and if he did, would be mildly embarrassed by it.

Norse Mythology is overall accurate, but misses some important details.

Loki in real life is a son of Laufey the Frost Giant King, not a fire giant. He also (AFAIK) had no children, and Hela is not his daughter but his older adoptive sister.

There is no Balder, and all the stories about Tyr, Thor and Balder are really just about Thor.

Other than that, most of NM stories about Thor and Loki are accurate, if simplified tales of their exploits.


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

[User]
[Xmen DOFP] How would the Sentinels deal with Wolverine?

Did they know he was there, and how would they deal with him when facing him?

[Assistant]
They could probably find a way to immobilize him and keep him in a constant kill cycle.  A cement mixer could probably do the trick.

Quoth the Master: "And the best part is, he comes back so we can kill him again!"


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

[User] ELI5: Why are there huge numbers of Africans and Asians living rough trying to sneak into the UK from France? Isn't France a similarly wealthy country?

[Assistant] France has national ID cards which are necessary to do anything involved in living an ordinary life i.e. open a bank account, get a job and so on. Britain doesn't have these, and also has a larger black economy because it doesn't aggressively pursue and punish the use of off-the-books labour to the extent that many other European nations do. There is also the fact that most of these migrants, excluding a few from Francophone Africa, are likely to have better linguistic survival skills in English than in French, and certainly than in Italian or Greek or whichever nation they landed in. Contrary to popular perception in Britain, asylum claimants are actually not especially well-catered to by the British government but they may receive a paltry amount of cash and/or food vouchers each week and be given hostel accommodation if it is judged that they have the right to have their claim heard. While this is very little it does still compare favourably with France where they get no assistance or accommodation except from the charitable sector, and are living outside exposed to the elements. It's these factors that create the popular perception among the migrants that they'll be better off in the UK. Some have through word of mouth sadly acquired delusional notions of making their fortunes here easily, others know that realistically they'll still be outside society and just existing, but under better enough conditions than France to make the last leg of the journey worth trying.


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

[User]
[Cowboy Bebop] What happened to the crew of the Bebop after The Real Folk Blues? (Spoilers)

There's so much left unanswered. Most prominently, Spike is questionably dead or severely wounded (even the Bebop wikia lists his status as unknown). Jet and Faye are trying to get over Spike going off on his suicide mission, but they're supposedly both still on the Bebop (despite not getting on great). Ed and Ein are presumably off looking for Ed's father or having *Ed*ventures of their own, but they hardly left the Bebop well-supplied in the first place.

All in all, what happened after Spike left to face Vicious?

[Assistant]
>There's so much left unanswered.

Yet you seem to have the bases covered!  Jet and Faye would survive, if only on a daily grind.  Ed and Ein would either catch up with Appledelhi or they wouldn't.

>even the Bebop wikia

Hardly a bastion of reliable truth, but in this case, it's the director who doesn't want to definitively confirm or deny.


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

[User] [Evangelion] Why can Evangelion units only be piloted by children?

[Assistant]
BTW SPOILERS.

Not children, the specific children that were prepared for the purpose. Their mothers were sacrificed in order the create the evas. That is the reason that they can sync with the evas, all accept rei who is a clone of shinji's mother as is her eva.


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

[User]
What would be the effects on western society of abolishing paid advertising?

It seems that so many wealthy people owe their fortunes to the effects of paid advertising (everything relating to TV and the internet, for example, not to mention political campaigning in the US).

The purpose of advertising is, after all, to "push" information about something out to the general public.  If this mechanism were to be removed entirely, then the public would need to seek out this information for whatever they are interested in, or, perhaps there is some model for how this might work in a society where advertising is provided as a public service by the government.

Has anyone ever done a study or simulation or thought exercise about how the removal of paid advertising would effect society?  I started thinking about this the other day and it got so huge and far reaching I became unable to think about it clearly.

[Assistant]
I can't speak to this exactly, but you could look into studies out of Sao Paolo, Brazil.

The city banned billboards, and some other forms of public advertising. Basically, the city looks a lot less cluttered.


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

[User]
Is there a direct connection between the Uncertainty Principle and the Third Law of Thermodynamics?

I understand that Thermodynamics deals with entire systems. But in the single particle case, if it can never be cooled down to absolute zero, it will always have some vibration/motion. This seems very similar to the Quantum Physics idea that a particle only has a probability to be at a specific range [delta]x. Are these two versions of the same concept?

[Assistant] There is not a direct connection between them. Even in a universe obeying classical mechanics, the third law of thermodynamics would still be true. The laws of thermodynamics don't discriminate between classical and quantum mechanics.


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

[User]
[Avatar: Legend of Korra Book 4] So exactly just how effective was the Air Nation and their humanitarian/peacekeeping mission?

At the end of Book 3, Korra is bound to a wheelchair and has suffered so much. She deserved time to sit back and heal, especially when she was close to being brutally killed by Zaheer. Because of this, during Jinoras airbending master ceremony, Tenzin declared that the new Air Nation will take up the mantle as a humanitarian and peacekeeping organization to help stabilize the former Earth Kingdom.

But just how effective was the Air Nation in helping to restore some sense order and providing aid to towns and villages in need? They seemed like they had a respectable reputation and have done some good but in comparison to Kuvira and her army, it seems to pale in comparison.

[Assistant]
There's an episode in Book 4 contrasting the Air Nation's efforts and Kuvira's. Kai and Opal try and get supplies to a town that is on the verge of starvation, but the supplies end up getting stolen by bandits. On the other hand, Kuvira's army is able to distribute supplies to that town without any interference from bandits, and actually have the numbers to garrison the towns they aid so bandits don't move back in once they leave.

It just seems like the Air Nation is spread far too thin, so despite the reputation for Kuvira's aid coming with strings attached, most states in the former Earth Kingdom end up concluding that aid with strings attached beats no aid at all.


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

[User]
Does Adrenaline really reduce reaction time?

I've always heard that in a stressful "fight or flight" situation, reaction time is reduced (in addition to increased strength, etc.); that being said it seems like the sort of thing that could be a myth or widespread misinformation.

I suppose the exact question I have is: Does adrenaline reduce reaction time and if so how, and by how much?

[Assistant] In essence yes, the sympathetic nervous system ("fight or flight") can speed reaction time to danger through this non-exhaustive list of mechanisms: dilation of the pupil allows for increased sensory awareness; increased blood flow into skeletal muscle allows for faster and more sustained muscular responses; finally the increase of the stress hormone cortisol has an effect in "priming" the brain to be hyper-aware of the surroundings, thus decreasing reaction time when a stimulus does occur. This is actually a really interesting direct connection between psychology and physiology.


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

[User]
[Marvel] Since Galactus appears different across the universe to different races and species, why do most humans view him as a giant-pink-helmet-wearing-weirdo?

So I read that Galactus doesn't actually look like a wacky dude in a weird constume, it's just that he's perceived differently for different species across the universe. Which makes me ask, why do then humans associate this force of nature with such a wacky look? Why does he have antlers on his helmet? Why is his mouth visible? I mean, why would you even think that....THING is a human? What's up with his outfit? Why's it pink and blue? And most of all, why is everyone perceiving him the same way?(are they?)

You give someone a description of Galactus and what he can do, no one would associate him with how he looks in the comics. So tell me why humans think he looks like that?

[Assistant]
In much the way that he has heralds, Galactus also chooses one person on the worlds he visits, using their thoughts and imagination to determine his form.  On Earth, his form was chosen by a brilliantly creative, but struggling artist named Jack Kirby.

(This idea was later stolen in another dimension by Gozer the Gozerian...)


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

[User]
If we could travel at the speed of light (or very close), wouldn't that make avoiding debris, asteroids, etc. impossible? (Sorry for another speed of light question)

We have to be able to detect debris far off in travel and navigate accordingly, but if we're already going close to the speed of light, what method would we use to detect debris that would be able to tell us in time?

[Assistant] It would be very very difficult indeed. One of the many potential challenges to interstellar travel. Granted there really isn't that much debris in space, especially of the asteroid variety. But a little speck of dust when you're traveling at those high speeds can be quite energetic.


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

[User] ELI5: Why does English not have a formal 'you' unlike other languages descended from Latin, like Italian?

[Assistant]
You *is* formal, as well as plural. What modern English lost was the familiar/singular thou. There's a line ~~in one of Shakespeare's plays where one character says to another~~ about Sir Walter Raleigh I thou thee, thou traitor! The use of thou in this implies that the speaker thinks so little of his listener that he refuses to use the formal pronoun.

Besides that, English is a Germanic language. Not a Romance language. It simply has a *lot* of words and influence from Latin, French, and Greek, especially in law and science.


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

[User]
ELI5: Why do we lose Appetite when we are anxious/Nervous?

Always happens and it would be awesome to dig a bit into the science of it as well.

[Assistant]
Much like the 'Fight or Flight' response related to real-world dangers and how we react to them, the brain has a hard time telling difference between a physical threat or a psychological one.

Anxiety and Nervousness can be as frightening mentally as a dark alley way or a guy with a knife across the street.

When your body goes into 'Fight or Flight' blood is moved away from the stomach and to areas where it might be used to run or fight, such as the legs or arms. Less activity in the abdominal region and an increase in adrenaline are some of the many causes to losing your appetite.

TLDR- Your body is allocating bodily resources effectively for a threat it perceives to be real and life threatening, but is really just mental anguish that it cannot differentiate.


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

[User]
ELI5: Does an airplane naturally follow the curvature of the Earth when flying straight ahead, or does the pilot make adjustments?

Say you have a plane flying a straight path. Since the Earth is a sphere, would the plane eventually be gaining altitude? Or does Gravity force it to follow the Earth's curve?

[Assistant] Assuming perfectly "trimmed" flight, it would follow the curvature of the Earth. Gravity always tries to pull it towards the centre of the Earth, so to carry on "straight" would actually include a component heading "up". The atmosphere is curved, so going "up" (by going "straight" would mean a loss of lift, and it would fall back in to the curve.


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

[User] ELI5: How is it that when dialing 911 it does not connect to another area code and always connects to a local one.

[Assistant]
I'll assume you're talking about dialing from a mobile phone.

When you make a call from a mobile phone, the signal goes through a cell phone tower.  Every tower has a unique identifier, which is sent with your phone number, the number you're dialing, and some other information to a central office, which is a place where lots of phone lines (virtual or otherwise) come together and have calls routed between them.

So, let's say you dial 911.  And you're currently communicating with a tower named Jeff.  Jeff then talks to the central office and says:

> Hey, it's Jeff, and Koppite93 just dialed 911.

The central office knows where Jeff is - to within a few inches - and sends your call to the 911 office nearest Jeff.

More interesting is, sometimes 911 can see where *you* are using some of that information.

If you dial 911, the 911 dispatcher can also see that you're near Jeff.  Depending on the software they're using, they may see more detail - like that you're near Jeff, and he sees you with about 50% signal strength.  The software will call other towers, and find out if they can also see your phone's identifier.

If the towers Jeff, Dana, Kelly, and Winston all see you with roughly the same signal strength, because you know where they all are you can draw a circle around each, and where they all intersect is your approximate location.  That calculation is called triangulation.

Science is neat!


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

[User] ELI5:How does phantom limb syndrome work?

[Assistant]
Your nervous system has been sending singles to your brain about how your limbs feel since before your were born. Right now, reach down and touch your pinky toe without looking at it. You can do this because your pinky toe is constantly sending signals to your brain with "status updates".

Now if your pinky toe was suddenly cut off, there is still a long network that takes signals form your pinky toe to your brain. These pathways have been in constant use your entire life. They are use to sending signals to your brain, and your brain is use to 99/99% of the time receiving the exact same signals. So even though your toe is not there, sometimes you brain forgets it is not there. As odd as that sounds, it happens.

The normal feeling is that you have a toe there. The new feeling is no toe. Sometimes your brain forgets there is a new feeling.


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

[User]
Why can't any computer run any program?

Why couldnt't a cell phone for example run windows, just slower because of less memory and other stats to the computer? Or what is it that prevents this from being possible?

[Assistant] The central processing unit (CPU) is a chip that defines what the instructions are that a computer understands.  The CPU in your phone understands a different set of instructions than the CPU in your laptop.  That said, programs like Wine and DosBox and MAME exist precisely so you can run programs compiled for one plaatform to run on another one.


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

[User]
ELI5: If the first living beings reproduced asexually, how did diverse species came to be? Also how did sexual reproduction started?

I understand that the first living beings were unicellular organisms, prokaryotes, which reproduce asexually. If DNA was only "cloned" from one organism to form an offsrping, how did different species appeared? I'm guessing it has to do with some kind of genetic mutation, but even then I can't wrap my mind around how sexual reproduction started.

[Assistant]
Well it helps to look at species that have various forms of reproduction between asexual and our form of sexual reproduction.

For instance prokaryotes can't go through meiosis but can incorporate new DNA from other prokaryotes.

Then there are some yeast cells that can reproduce asexually or sexually when under great stress.

Then there are various hemaphrodites in the animal kingdom.

Then there are species that can change sexes like clownfish.

Then there are true sexually dimorphic species like us.

Do you have a more specific question.

Edit: Also it helps to think that sexual reproduction (meiosis) is really just a modified version of asexual reproduction (mitosis) done twice. Then you just have specialization of specific parts and genders overtime.


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

[User] [Mega Man] How can Mega Man take multiple hits from Needle Man's Needle Cannon but if he steps on spikes, he instantly dies?

[Assistant] He's actually very, very heavy. He's made of metal and robot stuff, you know? When he steps on spikes, his full weight puts a lot of force on the point of contact and carries through to some pretty intense impalement. The needle cannon bits are just as pokey but make comparatively very light impacts, as megs isn't putting his whole chubby robot weight into them.


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

[User]
ELI5: why do you steer into the skid?

So there was this video of a woman managing to avoid a crash by steering in a special way. Im learning to drive rn and people keep saying if you skid you steer into it, but isnt that the opposite of what it feels like you would do?

[Assistant]
Yes, it is counterintuitive. This is why drivers should learn this in a school or something.

The reason is straightforward. The car that is skidding is no longer responding to the steering direction. Traction has broken down between the tire and the road and it is sliding.

Steering into the skid gives the driver the chance (as the car is slowing down) to regain traction by allowing the tire to rotate in the direction the car "wants" to go rather than simply sliding. Once this traction is regained, gently steering the car gives the driver some opportunity to direct the car and regain steering control.

If a driver does the intuitive thing and try to steer away from the slide, then the situation is made worse, the tires have no way to regain traction with the road and the car just continues to slide where it wants to due to momentum.


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

[User] How do we know that dark matter is real, and not a filler for our lack of understanding of physics?

[Assistant]
This has been asked and answered many times before.

It is just a filler, we know we have a lack of understanding. But we also know that whatever is missing has to have certain properties, and we call the stuff with those properties dark matter.


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

[User]
ELI5: Whats the catch in buying these homes that apparently costs "less than $100" in Detroit?

Surely there must be something I'm missing.

[Assistant]
These houses are in poor conditions in area of the city where nobody lives. Most people think "poor condition" and think how bad could they be?

These houses are the types that require $10,000 in plumbing wok just to have running water in the house. another $8,000 to have electric. $15,000 to replace the roof. Every window in the house needs to be replaced because they are broken or missing. No working HVAC system. Most have water and/or mold damage issues.

You have to fix all of these problems before you start to even think about carpeting or repainting or anything cosmetic.


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

[User] [WH40K] The C'tan, what's their deal these days? And how are they (apparently) the only living things with zero warp presence.

[Assistant]
Calling them "living" is kind of a stretch to begin with. They occupy a weird space between being dictated by physics and by thought.

Most of them have been shattered and are being used as power sources and/or weapons.

[Disclaimer: am not a Necron player and have not read the codex since fifth edition]


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

[User] ELI5: How does dunking a hot metal in cold liquid make it harder?

[Assistant]
Iron and steel can have a variety of different internal structures - the exact nature of the structure you get depends on a few things, but in iron and steel two of the things that have the biggest influence are carbon content and temperature.

Carbon content is a relatively easy one to alter, as it doesn't change significantly as the metal cools, but what can you do if you've got a desirable internal structure that's present only at high temperatures?

You can quench the metal... that's what. This rapid cooling means that the transition from the desirable structure to less desirable (i.e. softer) structures doesn't happen to the same extent, and so you end up locking in a structure that you'd normally only see at a much higher temperature in a metal that's now at room temperature.


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

[User]
Why do banks give out zero interest or negative interest loans?

Or for example, a 1% interest loan in a market that has 2% inflation. Why pay someone to take your money?

[Assistant]
Because losing $1 in real value for every $100 is better than losing $2. Banks also forecast in the long term- most loans mature well after a year, and the younger the loan the higher the interest (typically).

A hypothetical 30 year mortgage might have a negative return today at 1% interest, but if interest rates go lower it will reverse, and if they don't then the rates will be increased once the rate is changed if the loan has variable rates.


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

[User]
[ATLA] Suppose the Avatar spirit ever "skipped" a nation, or perhaps even more...

Avatar takes place in a time period where tech and medicine is comparable to a real world period in which death in early infancy was common.

If the Avatar reincarnated into the air nation after Roku died, but then suffered a fatal disease within a year, does the spirit immediately get reincarnated into the water nation?

What would happen if this caused the avatar to "skip" to the water, earth, or fire nation before the war started? Would the water nation better defend from the fire? Would he be far better protected in the earth nation? Would the fire nation laugh triumphantly as they try to use the new Avatar as a weapon of war?

[Assistant] I would assume that if the child were to get gravely sick the avatar state would kick in and help see the child through it. We see this in Korra when they give her the metal poisoning and the avatar state turns on trying to cure her.


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

[User]
[The Expanse] Why aren't Belters UN citizens?

They had to come from somewhere, they weren't fabricated in space. There doesn't seem to be any indication that their ancestors were legally exiled and stripped of their citizenship or voluntarily renounced it. They just moved to space and a few generations later there's a pseudo-slave underclass with no rights. How (not) on Earth did that happen?

[Assistant]
As soon as stations like Ceres and Eros became semi nation states, run by corporations, people born on them no longer qualified for citizenship. They probably had some clause saying "must be born on Earth, Luna or a UN ship/colony". So if a belter accidentally popped out a baby in the UN Embassy on Ceres then they probably qualify.

Furthermore there was probably political tension caused by the UN trying to claim all those born throughout the belt were UN citizens, Mars probably had a fit saying some of them were theirs, in the end they probably just agreed to leave them stateless.


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

[User] ELI5 : If we never manage to create a true absolute zero, how do we know that it sit exactly at -273.15 c instead of ,uh, -273.69 or something else?

[Assistant]
Background: As temperature drops, the pressure that a fixed volume of gas exerts on its surroundings drops. As temperature increases, pressure increases.

Basically, the relationship between pressure and temperature of a gas is really well understood and well defined. We can take various pressure measurements at various temperatures and plot them on a graph. That plot shows a perfect straight line. We then just follow that line down the temperature axis until we see where pressure drops to 0. You can't have a pressure below 0, and so at that point we know the atoms of the gas have basically stopped moving, which we define as Absolute 0.


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

[User]
Chernobyl physics questions. Why did they turn off the pumps?

This is a questions on physics and the events leading up to the Chernobyl disaster. Also concern nuclear energy etc. Sorry reddit keeps rejecting this post so trying to cover all bases.

Apologies if this has been asked before or this is the wrong subredit, but here goes:

From my reading on the events leading up to the disaster the plan was to check if the turbine had enough latent pressure to power the pumps in the event of power failure whilst waiting for the diesel generators to be up to speed. Given this, it seems in the buildup to the disaster they actually did cut steam to the turbine and see if the pumps worked until the diesels were online, and thus reduced coolant at the critical moment. I understand it wasn't the sole cause but it was a factor.

My question is since it was known how much power the generators produced (5.5mw if memory serves), and they must have had some means of measuring turbine output. Could they not have just carried out the test without actually cutting off the power to the pumps? As I say I know there were many other contributory factors but this seems an easy way to test the turbine capabilities without risking anything? My reading is listed to Wikipedia/various documentaries and Web sources, so hopefully someone can fill me in. I understand that no test like that is the same as real world, but surely carrying it out 'my way' then applying a risk factor would work? Thanks :)

[Assistant]
So lets start from the top.

This test was to verify the coastdown effect on the reactor coolant pumps following a loss of offsite power with a load reject turbine trip.

The test was specifically designed to ensure the reactor was in a safe operating region for the test. If the test plan were followed, there would have been no issues as it was completely pre analyzed.

The coastdown time of the RCPs is a critical input into reactor safety analysis. BWRs simply utilize natural inertia of the RCPs for safety. PWRs will use large flywheels to ensure sufficient coastdown time. In this case, the RBMK design was utilizing generator coastdown and decay to support the coastdown time.

You cannot simply look at the turbine output. After the turbine trip, you are going to have coastdown. All the major pumps on that bus will actually oppose the coastdown, and help extend the coastdown time, in addition to the generator coasting down using residual inertial from the turbine generator. This test data requires your loads to remain on the bus in order to get an accurate depiction for how voltage/frequency decay is going to occur. Today you can model it pretty closely using computer models, but in the 70s/80s you didn't have the same in depth models, and you had no physical data to validate the theoretical data, so you had to do the actual test.

Cutting off power to the reactor coolant pumps did put the reactor into the restricted operating region. All water reactors where there is active boiling have instability regions when they are at high power with low reactor coolant flow. What happens is the water flashes to steam, and because of insufficient flow, the steam doesn't get pushed out of the core, and instead, acts to further lower coolant flow by creating back pressure. In a BWR, this causes power to go down dramatically, which causes boiling to stop. Then natural circulation picks up again and power rapidly increases. This creates core oscillations which can cause fuel damage if left unchecked.

In an RBMK reactor, because they have a positive void coefficient, the worst case is that the steam and back pressure cause power to further increase, which makes more steam, more heat, more power. To ensure this does not happen, the RBMK had a safety limit on a minimum number of inserted control rods to ensure that the reactor was slow enough that natural feedback mechanisms like fuel heatup could counteract the voiding effect, and buy time for an automatic or reactor operator scram if the condition didn't get better.

The reason this accident occurred, was because the operators violated the test plan and intentionally put the reactor into the restricted operating zone before even performing the test, while simultaneously violating their safety limit. Tripping the main turbine and offsite power would have been safe in the pre-analyzed region, but they weren't in the analyzed region, and it did make the event worse. Having all the rods out past the safety limit also made the scram worse, as if those rods had already been partially inserted as pre-analyzed, there would have been very little or no positive reactivity insertion.

The bottom line, is that multiple things together compounded the prompt reactivity spike by the graphite tipped control rods, leading to the power excursion and near immediate core damage.


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

[User] ELI5: The countless little arcade games on sites like Miniclip, Armor Games, Kongregate, etc...Why are they made? Are people paid to make them?

[Assistant] They are made from people who enjoy developing flash games. Sometimes they make money, sometimes they don't. Most everyone who does it has an idea for a little game that they or others might enjoy. It being small and free allows it to be posted and played on these sites, so many people can enjoy the games. Some people do it as a hobby and others might do it to extend and further their programming languages.


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

[User] [MCU] Does War Machine property belong to Colonel Rhodes or to the US military or to the Avengers? If the Avengers needed him at the same time as the US military, who has precedence in that situation?

[Assistant]
All indications- his big press conference in Iron Man 3, and his story in Age of Ultron about de-escalating a foreign conflict that none of the other Avengers were aware of- suggest that he places his duties to the military above his duties to the Avengers.

Unless the guy giving orders is a dickhead like General Ross and there's a space overlord coming to Earth right this minute and screw the Accords anyway.


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

[User]
Every time I look this up, I get conflicting answers - can anyone delineate the conditions under which it is valid to use a one-tailed t-test, as opposed to a two-tailed one?

Thanks in advance.

[Assistant]
Hypothesis testing is fundamentally designed to control your type 1 error: the probability of mistakenly rejecting the null, when the null is actually correct. In laymen's terms, we might interpret this as "the probability of wrongly taking action if we're in a situation where we shouldn't take action".

By design, hypothesis testing will fix this probability at a pre-specified rate, regardless of other types of mistakes (more on that in a second). In the most common significance level (95%), this means that there is a 5% chance we will mistakenly "take action" in cases where there isn't actually an effect happening. Note that this doesn't inherently tell you anything about how you perform in cases where there *is* something happening; that's covered by statistical power.

Now, a t-test is comparing two values (usually sample mean vs. null, or sample mean vs. another sample mean). Suppose we "take action" if either value is evidently greater than the other. This is the two-tailed test: there is a 5% chance that we mistakenly conclude one value is greater than the other. Since either outcome results in taking action, there is a 5% chance of committing a type 1 error.

Alternatively, suppose we only "take action" if value 1 is greater than value 2 (e.g. if some new strategy out-performs an old strategy). If there isn't any actual difference between value 1 and value 2, then it doesn't actually matter if we mistakenly conclude value 2 > value 1, since we won't "take action" in response (we'd simply keep the old strategy). This means that our outcome has only a 2.5% chance of a type 1 error where we mistakenly take action, so it doesn't make sense to report a 5% type 1 error rate. To address this, a one-tailed test is actually the equivalent of a 90% significance test, but only looking in one direction (looking for value 1 > value 2).

There are other valid ways to handle critical regions, and not all hypothesis tests are as symmetric / well-behaved as the simple t-test, but this is sufficient for a beginner's level. It also ignores any consideration of statistical power. Note that if you are performing a one-tailed test, this means that you would know which direction to look at *before collecting any data*, strictly from the context.


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

[User] ELI5: Why if I eat before going to bed I wake up painfully hungry but if I do not eat right before going to sleep I wake up feeling fine?

[Assistant]
Even though you are asleep, your body is processing the food you eat.

Imagine your body is a big shipping warehouse. Normally, at night time, there's a very small crew just managing small amounts of packages. If at once, a large shipment arrives (you eat before sleeping), they will have to call on additional workers and charge them overtime in order to process and store the shipment promptly. If the shipments are not processed, they may cause issues for the shipping warehouse.

The overtime workers arrive and process and store the shipment but now they're annoyed that there's not much more work. You called them in from resting in their homes for just a single shipment?! They start complaining and want the supplying company to give them more shipments!

This is what happens when you eat before you sleep. Your body will automatically digest the food and put the nutrients into your body. The nutrients have to go somewhere or else the high concentration will be toxic to your body (for example, high blood sugar). One type of protein, insulin, helps push sugars into cells. However, if you eat a lot, more insulin has to be released to process all that digested food.

When there is too much insulin in your body and not much sugar for it to work on (after it's done processing the food), it will trigger a sense of hunger that you will get when you wake up.


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

[User] ELI5: Why can you have a meat stuck in your teeth for a day and when you swallow it you're fine, but if you leave the same meat on the counter for a day and try and eat it, you get sick?

[Assistant]
A good question. Why can you infect milk with bacteria and get yogurt instead of spoiled milk? Why does Italian dry salami keep without refrigeration even though it's inoculated with lactic bacteria for tartness?

The answer is "competition". Food on the countertop is up for grabs by any bacteria, insects, fungus, or animals that can get to it. It can become a battleground as single celled organisms battle it out for who gets the food. Because the war starts with everybody on equal footing. Nobody has an initial advantage.

When you have food stuck between your teeth though, the bacteria in your mouth have a home field advantage, and can quickly coat the piece of food, similar to inoculating a petri dish with bacteria. Thus by the time other bacteria or fungus can finally make it into your mouth to find the food, there is already an entrenched army of mouth microbes dug in and ready to battle it out. You also have fungus growing in your mouth as well, but it's kept in check by the bacteria, which is kept in check by the fungus. Sometimes when someone takes antibiotics, it kills the bacteria, giving the fungus an advantage, and it reproduces so well you end up with a layer of thrush on your tongue. It's all about balance and playing one side off the other.

The same happens when you ferment beer or leaven bread. You introduce a preferred organism like yeast, and give it a good place to reproduce rapidly, and it in turn will defend the food from other microbes.

Don't forget that penicillin is a drug derived from a strain of fungus that had developed it in order to fight off bacteria that competed for the same food and habitat. Microorganisms fight each other all of the time for food and shelter.


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

[User]
ELI5: How can charcoal burn when it's made from from burnt wood?

Shouldn't all the innate energy already have been used up during the initial combustion leaving you with material equivalent in flammability to ash.

[Assistant] Charcoal isn't burned wood. It is produced by heating the wood in an oxygen free environment, which prevents it from burning. The heat causes liquids and gases to be expelled from the wood, leaving a solid residue that is made up mostly of carbon, which is more combustible than plain wood.


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

[User]
[Watchmen]Is there anything Dr. Manhattan is NOT capable of?

I've only watched the movie, and in that he seemed pretty much omnipotent and nigh-omniscient, despite being tricked by whatshisface. Is there actually anything in the comics that he verifiably failed to do or admitted that he couldn't do?

[Assistant]
He claimed that, if it came to nuclear war between the US and Soviet Union, he would not be able to stop all of the Soviet missiles before they detonated. Some think this was a bluff on his part, though. If not, that puts a very hard cap on his maximum energy expenditure and ability to multitask.

He's also incapable of accessing his full temporal memory when hit by a reversed polarity tachyon flow, or whatever the fuck Oz called it.

He's also bound by that temporal memory. When the SQUID detonated, it became a fixed fact, and Manhattan was unable to inform himself before it happened in order to prevent it. Basically, he cannot violate causality.

This also implies that he cannot travel faster than the speed of light.

Emotionally, he's unable to relate to his former humanity, or forming genuine connections with mortals.

The real issue, though, is that he's largely untested. We haven't seen him go all-out, so we don't know what he's capable of ... or what he isn't. He might be weaker than Silver Surfer or more powerful than Living Tribunal. Without feats, we just don't know.


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

[User] ELI5: Why do two headphones make the music play in the top of my head? A left or right headphone on its own is noticeably left or right, but as you place the second one in, rather than it sounding like its coming into each ear simultaneously, it just sort of like, swims up in the top. Why?

[Assistant]
The brain uses loudness and time-based cues to determine whether a sound is coming from left, right, or center. If only your left ear hears, say, a cymbal crash, your brain concludes it must be coming from straight to your left. If both ears hear the strike at equal volume and at the same time (as opposed to the noise reaching one ear before the other), your brain concludes it's coming from the center.

As for why music might seem to be coming from the top instead of in front of you, another stereo imaging cue you hear would be the set of resonant peaks and dips in the treble caused by sound waves being reflected off the bowls of your outer ears at various angles before reaching your eardrum. For whatever reason (maybe tuning, maybe headphone cup angling, maybe something else), your brain interprets the highs your headphones generate as coming from the top.


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

[User]
Will the rings of Saturn eventually become a moon?

As best I understand it, the current theory of how Earth's moon formed involves a Mars sized body colliding with Earth, putting a ring of debris into orbit, but eventually these fragments coalesced to form the moon as we see it now. Will something similar happen to Saturn's rings? How long will it take.

[Assistant]
No, they can't form a moon.

\[Geologist here, keeping the seat warm until an astronomer arrives\]

There is a distance from the centre of a planet called the Roche Limit inside of which objects can't accumulate to form moons.

Very simply, a particle in a lower orbit (closer to the planet) feels a slightly greater gravitational pull from the planet than a particle further out - so there is a force pulling the pair apart. If this tidal force is greater than the gravitational pull between the two particles, they will separate from one another.

The majority of Saturn's rings lie inside the planet's Roche Limit so they can only ever disperse. The two outer rings are outside of the limit so their origin is less certain.


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

[User]
ELI5: How mopping cleans a floor rather than just redistribute filth.

I'm not saying it doesn't work, but like... how exactly?

[Assistant] Most of the dirt becomes attached to the mop. If you never washed out your mop, it would eventually become so saturated that it left as much dirt on the floor as it picked up. But if you rinse/squeeze your mop, or dip it in water, most of that dirt gets transferred to the water and ultimately goes down your drain. Mops can be pretty absorbent, so it might not seem like it needs to be rinsed out for quite some time. (Although more frequent rinsing may result in cleaner floors.)


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

[User]
ELI5: How does patient zero get sick?

When a new outbreak starts, how does the first person get sick? Is it from asymptomatic carriers, travelling and picking up foreign strains of illness, mutations, or what?

[Assistant]
Few options.

Then can be the person in which there was a mutation that allowed the disease to evade the community's immunity. Or they can be the person who brought the disease from a foreign country, or caught it from an animal.


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

[User] ELI5: How does electricity "know" what is the path of least resistance?

[Assistant]
Because it isn't resisted.

Think of trying to move through a crowd. You can try to push past the 300lb biker with LOVE tattooed across the knuckles of one hand and HATE across the other; or you could slip past the 22 year old hipster kid who weighs less than 100lbs because he eats exclusively lentils and kale. One of these options is much easier than the other, and you can tell simply by trying both.

So, of course, you're going to end up going past the biker because he isn't going to lecture you about GMOs and the beef industry.


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

[User]
[MCU- The Avengers] What if Coulson was sent to recruit Banner, and Black Widow to Stark?

Just watched Avengers again and noticed that Black Widow expected she would would be sent to recruit Stark. What if she was right? Would either of them have failed? Would Banner and Black Widow still have the same relationship? What small details do you think would be different?

[Assistant]
Coulson definitely would have been successful getting Banner.  His genuineness is very disarming and Banner would have figured he could trust him, same as black widow.

Nat probably would have had a harder time with Stark though.  He doesn't trust her one bit and Coulson also had the relationship with Pepper that helped that along.


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

[User] ELI5 how did water appear in Earth and how did we end up with such vast amount of it?

[Assistant]
Water is Hydrogen + Oxygen, two of the most abundant things on Earth.

Much of the Earths crust is made up of Oxygen, bonded to other things like Iron to make minerals.

Since a lot of Oxygen existed on the primeval Earth, and Hydrogen is the most abundant thing in the Universe, having water was inevitable.

So where did it come from? Either the Earth was formed from material that contained a lot of Oxygen and Water, or the early Earth was bombarded with Comets and Asteroids that contained Oxygen and Water.


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

[User]
ELI5: Why doesn't Russia have a warm water port on it's Black Sea coastline?

Like the question states, why don't they have one on their own coastline? It seems like it would be easy to create their own warm water port so that they wouldn't have to worry as much if their lease at Sevastopol would be revoked.  I realize that the port issue is a smaller part of a bigger problem, my question is more in regards to Russia's timeline as a whole on the black sea, why haven't they ever built a warm water port on their coast?

[Assistant]
> It seems like it would be easy to create their own warm water port

Possible?  Yes.  Easy?  No.  Naval bases are complicated, huge, and expensive.  Russia *is* actually making another one, at Novorossiysk (on the Russian Black Sea coast, halfway between Sevastopol and Sochi).  But that was started when it looked like they might not have Sevastopol forever.  Before then, why would they?  Sevastopol was theirs for centuries.  They wouldn't really need to.

So the short answer is that they are making another one.  But it's not finished yet.


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

[User]
It is stated that a wall is necessary as illegals are depressing pay and taking jobs. Statistically, there are roughly 8 million illegals working out of 125 million working in the country. How much does that depress pay?

Trying to look at this on a statistics/economics level not a political and emotional level. And please, I get that this will definitely affect some people in some industries more than others (I am sure a construction worker in CA is affected more than a computer programmer in Idaho.

Do economists have an idea how much 8 million additional workers affect wages? Even with illegals, unemployment is low. SOME illegals take jobs others don't want. So maybe 6 million jobs that Americans want are taken by illegals. Can economists, statisticians figure out where wages would be if there were 8 million fewer workers, (6 million?)

[Assistant]
Despite the rhetoric, there's no economic consensus that immigrants (legal or otherwise) depress wages at all. Borjas research suggests that immigrants may depress wages slightly for some specific segments of the population (low skill natives without a high school diploma) while remaining a net benefit, but even that is contested.

The reason is that immigrants are consumers as well as laborers, and the increased demand for goods seems to offset the downward wage pressure.


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

[User]
ELI5:Why do colds have 'stages' and attack your nose and throat at different times?

 I would expect a cold to attack your whole body more or less at one.. instead you'll hear "first it was in my nose and I was congested, then I had a sore throat, then I had a runny nose, etc. I would think that the virus would be able to get to your nose and throat at relatively the same time.

[Assistant]
The progression works kinda like this. You inhale the virus, it gets lodged in your nose let's say. It starts attacking and lysing cells, because that how it be. The body responds with inflammation and an increase in mucus production, which contains the active immune components. Your post nasal drip brings it down to your throat, which the virus then attacks and wreaks havoc. As luck would have it, a couple times when you breathe in you accidentally pull some of this post nasal drip / throat mucus into your lungs and voila, now you have an infection there. Since you usually swallow your post nasal drip, this can give you the vomiting and nausea component when your stomach fails to breakdown the viruses, which causes it to freak out and push the panic button, making you throw up. The change in symptoms from a stuffy nose to a runny nose is your body trying to fix it, and this leakage is what makes it mobile.

It can't attack systemically because it's not mobile enough. It's like living in a big city, if you don't have a means for transport you'll never leave the neighbourhood. For it to do that it would have to be in the blood stream, which is why when you get an attenuated vaccine you can get sick all at once. This isn't dangerous though because cold viruses target only the respiratory tract with a little bit of the digestive tract thrown in for free.


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

[User]
[The Sims] What disaster occurred in the world of The Sims that caused the average human lifespan to drop to less than a year?

In The Sims the average lifespan of a Sim is something like 90 days, during which they age from a baby to an elder, gain an education, job, and can reproduce. What disaster befell the world to cause the human lifespan to become so short?

[Assistant] Time sped up, but schedules never changed. It takes 3 hours to get ready for work and an hour to walk from your bedroom to the driveway. Your ride doesn't wait, even if they can see you coming. Miss work, get fired, get depressed, dance in puddles of your own urine because you're too upset to clean or eat or sleep.


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

[User] The mass of most very large stars are only in the range of 10-100 solar masses but the radius is on a scale of 100-1000 solar radii. What is the "surface" like on these stars, is it extremely less dense than are Sun or do these stars have a different internal structure to maintain surface density?

[Assistant]
more mass means that gravitation is stronger. But that also means that the nuclei at the core have more thermal energy and are able to fuse more often. Thus they give off heat more strongly than lighter-massed stars.

So kind of like any gas, the hotter it is, the more volume it needs (pressure here being set by gravitation). So yes, like you suspect, the stars are less dense in the outer shells, but the gravitation still is sufficient to drive a hotter core (compared to a smaller star)


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

[User]
[Star Wars] How long can Darth Vader last outside of his suit? (Minor Rogue One spoilers)

Like if he's chilling in his bacta tank on Mustafar when alarms go off and the Rebels are breaching his chamber meaning he has to defend himself without enough time to suit up? I expect the Force can sustain him for a short while, but how long exactly?

[Assistant]
It'd likely be quite a while: "The dark side of the force is a pathway to many abilities some consider to be *unnatural*".

With enough hate flowing through your body you can literally will yourself away from death. Darth Maul did it, Vader did it on Mustafar for several hours. Darth Vader has a lot of hate, especially at this point in his life, and it only increases until his encounter with Luke on Cloud City.

He died on the Second Death Star after his life supports systems were fried because he let go of his hate. His last action was one he knew would result in his death, and he went through with it anyway.


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

[User] ELI5: How do chess computers work?

[Assistant]
There are two main components, a static position evaluator and a search tree.

The position evaluator looks at the current position, and gives it a score, mostly based on material but includes other factors as well.

The computer then builds of a tree of all possible moves for say, the next four moves.  It scores all the resulting positions, and decides which move leads to the best outcome.

There is a lot more to it, but that is the core of what a chess computer is doing.  And since it is computer, it can look at millions of positions before deciding its next move.


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

[User] [LOTR] Isildur, Gollum and Bilbo all call The Ring "precious". Is this a bug or a feature of The Ring? Is there a reason Sauron was particularly attached this phrase when he forged The One Ring?

[Assistant]
Sauron's original name was Mairon, but this was changed to Sauron after he was corrupted by Melkor (think how Anakin's name became Darth Vader).

Mairon comes from the Quenya word *maira*, meaning "beautiful, admirable, **precious**". The Ring, imbued with a piece of Sauron's soul, remembers his true name, and compels those who bear it to name it as such.


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

[User]
[Chamber of Secrets movie] Does nobody care that Lucius Malfoy tried to kill Harry on school grounds?

Spoilers for a movie that's been out for more than a decade.

At the end of chamber of secrets, Harry tricks Lucius Malfoy into freeing Dobby. Enraged by this, Malfoy whips his wand out and starts to yell "avada kedavra" before Dobby incapacitates him.

How the hell did Malfoy think he could get away with this? Did anyone at the school even care that he almost killed a student?

[Assistant]
No-one saw him except harry potter and a house-elf. No-one's going to take a house-elf's word over a Malfoy's, and Harry at this point doesn't know what Avada Kedavra is so he has no reason to think it was anything more then Lucius trying to hex him with some unknown spell, and this no reason to report it.

Malfoy was very lucky he was incapacitated- had he *succeeded*, people would have very easily put the pieces together. Luckily for him, he failed, and so it never spread.


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

[User]
ELI5: Why are video games/dlc's primarily released on weekdays?

I mean, wouldn't it be smarter to release it on a Friday or something so people can play it all weekend?

[Assistant]
There's a few good reasons. There's better media coverage during the week, so you're more likely to get press for your release than you would over the weekend. Second, a lot of times with game releases, there's server issues/emergency patches as problems become apparent when a large number of players come online at once. The first few days after launch are generally pretty busy for the dev team, and they'd probably prefer to be doing that work during the week rather than the weekend.

And if you release a game on Tuesday, people can still play it all weekend, they just have to wait a few days first.


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

[User] ELI5: Why is China building a space station of their own instead of collaborating with other countries?

[Assistant]
China had expressed interest in joining the International Space Station project in the past, but the United States had blocked them on fears that they would take the technologies they would gain from the experience for military purposes.

Please note that Russia is allowed to participate in the ISS despite similar concerns previously.


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

[User]
A 31 year old philosophy student with a personal question.

So I have never felt as dumb as I do in this program. Is this a common occurrence to feel like the readings or concepts are tough to grasp?  I'm also constantly agreeing with a new reading only to agree with the criticisms of the idea, perpetuating this feeling of knowing so little. I'm really just reaching out to see if others have the same experience.

[Assistant] Yep. Philosophy is really hard. Focus on understanding the arguments as best you can. Read things very carefully and take notes if they help you work through stuff. As you read more you may find yourself building up a particular set of views you think is right, or perhaps not. Just reading carefully and thinking very hard about what you read means you're doing the right thing. If you're not sure about things, try reconstructing the arguments in your own words.


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

[User]
ELI5: Why does Japan get special editions of albums?

I've always wondered why Japan gets special editions of albums with bonus tracks that sometimes go beyond the deluxe editions you can buy in the rest of the world.

[Assistant]
With the explosion of consumerism in Japan, it was quickly noted that the Japanese are a nation of avid collectors; to an almost obsessive degree, if they like something they REALLY like it, and will buy the t-shirt, the book, the posters and the sticker album of their favourite musician, as well as all the albums.

Record labels realised that if they therefore released "Special Editions" of already-released albums, with a few extra tracks (B-sides and live versions, mostly), then you can get twice as much money out of the Japanese market, because their obsessive collecting FORCES them to buy both versions of the album.

Of course, not every consumer in Japan has OCD. But the fallout means that Western consumers with OCD would pay EVEN MORE to get the "Japanese only" versions of the albums, pushing profits even higher.


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

[User]
[Harry Potter] Does the Time Turner demonstrate there is no free will in the Potterverse?

When Harry and Hermione used it, nothing changed.  They, in fact, participated in events exactly as they remembered them from before the Turner was used.  That would seem to indicate that they had no choice but to act as they did, even though they didn't seem to know their actions were constrained in that way.

So is this an indication that there is no such thing as free will?

[Assistant] Not at all. It's simply a stable time loop. Think about the documentary of the WyldStallyns before they revolutionized the world: *"Remember the garbage can,"* <trash can falls on the head of person in front of Bill>. The events only transpire the way they do because they resolved to make those decisions. Every result was directly from their personal choices, not predestination.


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

[User]
[Harry Potter] In Book Five, when Harry serves detention with Prof. Umbridge, she has him use a special quill.

This special quill wrote in Harry's blood and caused scarring to Harry's hand. This is a form of corporal punishment, which is not allowed at Hogwarts. However, Harry decides not to tell Dumbledore or any other staff member.

What would have been the fallout if Harry had gone to Dumbledore right away to show him what Umbridge was doing?

[Assistant]
Dumbledore tolerated Umbridge due to the difficult political situation he was in, but showed willingness to abandon political expedience to physically protect students, such as when he cursed Umbridge in front of witnesses to stop her shaking Marietta.

As well as that, discovering a magical torture device in her possession could have been a potential advantage for Dumbledore: even with the press so heavily against him, Dumbledore has enough leverage to publicise the Ministry using probably-illegal cursed items on children.

All told, if Dumbledore had known, he would probably have gone full meddle-not on Umbridge and hauled her before the Wizengamot. There's no particular indication that Fudge would have been willing to risk his already-precarious position to defend her. It wouldn't have been enough to restore Dumbledore, but it would have got Umbridge removed from Hogwarts and damaged the Ministry's position.

Even if it didn't work out like that, Dumbledore would *definitely* have destroyed the cursed quill and kept a much closer eye on Umbridge.


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

[User]
[X-Men: Apocalypse] We saw Apocalypse enhance the mutant powers of his recruits. Had Cyclops joined him, would Apocalypse "fix" his eyes, allowing him to control it the optic blasts?

Basically, does Apocalypse have the ability to mend Cyclops' eyes so that he no longer needs to wear glasses/visor? Or does he just amplify the beam?

[Assistant] He'd probably do both. A while back in the comics, he merged his body with Cyclops' to make a weird hybrid of themselves which had a giant eyehole that could shoot optic blasts at will, and also fire the same energy out of its hands.


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

[User] [Halo] If Forerunner technology was locked to Reclaimers (Humans), then how could the Covenant reverse engineer and use their technology?

[Assistant] The Covies had the Huragoks, biological engineers capable of self-replication and created by the Forerunners to maintain their tech. The Covies basically blackmailed the Huragoks into helping them gain Forerunner tech through threat of destroying said tech via ignorant use.


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

[User] ELI5 Why do countries like Russia have harsher winters than other countries which are on the same latitude?

[Assistant] Because Russia has huge landmass with very little ocean contact.  Conversely, the southern hemisphere has a lot of ocean area with relatively little land.  The ocean and its currents hold and move a lot of heat around the globe. Without proximity to the heat held in the ocean during the winter, Russia cools more drastically.  On the other side, the southern hemisphere experiences smaller temperature swings with the seasons.


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

[User] ELI5: Why do different countries have different electrical outlet layouts and voltages whereas (almost all) cars/trucks are standardized at 12v and the little round outlet (cigar lighter)?

[Assistant]
Cars wear out and get replaced, so over a period of two decades 99% of all cars on the road will be replaced with new ones.  The last several decades in the auto industry have been ones of consolidation into a few enormous multinational companies that sell cars in dozens of countries around the world.  So they've standardized, and that standard can be seen in every vehicle you're likely to enter.  There are still the odd 6V and 24V vehicles out there, just not many.  Same thing with computer/phone connectors: a few standards take hold and spread worldwide.

On the other hand, electrical outlets installed in the 1920swhen even different parts of the same country might have different standardsare still in use in millions of homes.  The cost and difficulty of retrofitting is not inconsequential, nor is there much need to, so long as appliances are imported country by country.


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

[User]
CMV: The United States is going through another Gilded Age.

The Gilded Age in the US, for those who don't know, was a time period that was characterized by rampant corruption in the government and big businesses, big businesses basically having total control over the federal government, anti-union sentiment, mass influx of immigrants getting paid poorly, a very strong economy, horrible environmental protection, and hyper-partisanship.

This is almost *exactly* what the US is going through at the moment. Our congressman work for their highest donors and lobbyists, and once again, money and big corporations have nearly unlimited power in the federal government. Millions of immigrants currently in the US are getting paid well below what is the federally accepted minimum wage in order for businesses to maximize profits. The republican party especially dislikes worker unions which force corporations to treat their workers fairly. The republican party also has dislike of the EPA (that they set up) and a weird love of removing regulations set up to protect the environment. The hyper-partisanship of today also closely reflects that of the gilded age, with one party in bed with big corporations and another staunchly opposed to them.

[Assistant] I think you're misunderstanding the Gilded Age. It's called that because yes there were social problems but it was all hidden under a gold layer, the problems were "gilded" so people didn't worry about them. So the very fact that you're being so open about our problems and all of these problems are problems people deal with and know about and many people want to work against prevent this from being another Gilded Age. We know our age isn't golden.


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

[User]
ELI5: How are magnets in the road used to regulate traffic lights?

I was at a traffic light and I could help but notice that there were a bunch of metal lines in the road. I 'm assuming that the lines are magnets or something that helps the traffic lights to know when to switch. I was just wanting more detail on exactly how the system is supposed to work.

[Assistant]
Traffic light sensors, at least historically, are specialized metal detectors embedded underneath the road. They don't use magnets specifically, but they detect how the presence of metal in a car above it alters the electromagnetic properties of the space around the coil.

However, most municipalities are moving away from these kind of sensors though, in favor of miniature radar based sensors that mount to the signal post itself.

Under-road type sensors are extremely  expensive to fix when they do fail, as this usually requires tearing up the road for at least 24 hours  (and thereby obstructing traffic.)

Having a small radar sensor that mounts above ground, which you can replace in 20 minutes with a cherry-picker? This is a no-brainer.


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

[User] ELI5: Why does eating after taking a pill help the pill take effect?

[Assistant]
Sometimes it's actually because the designers want the pill to take effect *slower* than it would on an empty stomach. Drug and alcohol users know from experience that taking things on an empty stomach will make the things hit harder and faster. When you have food in your stomach, things are absorbed a little bit slower because they have to be "sucked out" of the wet food mixture as opposed to being in solution.

Compare it to sucking the liquid out of a blended ice drink (like a frozen  margarita, daiquiri, or a slurpee) instead of a drink with no ice.


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

[User] Is being unconscious from anesthetics the same as sleeping in terms of brain activity?

[Assistant] no, unconsciousness is different from ordinary sleep, because unconsciousness is an induced brain state where most activity ceases and you will not wake or respond to external stimuli that would otherwise wake a person up, but in normal sleep the brain is just as active as when you are awake, sorting, compressing and putting info into long term memory.


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

[User]
ELI5: In a recording studio, why use studio quality headphones, when most people won't be using those to listen

Studio quality headphones give accurate representation of sound, but most people listening to the music won't be listening with that high quality, so they'll miss a lot, or it might sound quite different for them.

[Assistant] Because you want the source recording to sound as good as possible.  Many people use quality speakers or headphones. Any recording is only as good as the weakest component in the chain, so you start high and then if people want to have a degraded experience that's their choice, but you don't cater to the lowest common denominator because then there is no quality version of the thing you just spent a lot of time and money to create.


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

[User] How can astronomers work out the size and mass of exoplanets when they're literally just a few pixels wide in a photograph?

[Assistant]
In very simple terms, the size of an exoplanet can be approximated by measuring how much the star's brightness dips as the planet passes between the star and Earth. The reduction of brightness is going to be proportional to the occlusion caused by the planet.

The mass of a planet can be inferred from its radial velocity, which can be measured by the orbital wobble that it causes in the parent star. This can be calculated by measuring red /blue shifts in the star's emission wavelengths during the planet's orbit.


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

[User] ELI5: What's going on with Russia and is the US actually at DEFCON 3?

[Assistant]
The United States is not at DEFCON 3. A quick google search showed this.

What's going on with Russia is that Russia wants Ukraine, but can't just do a big invasion for fear of starting WW3. Other countries are warning Russia not to, but aren't doing anything besides economic sanctions (which are totally trashing the Russian economy) and saying that they support the government of Ukraine. This is for the same reason that Russia isn't giving a full military contribution, because nobody wants a full scale conflict, which is what Ukraine could quickly turn into. Nobody wants to directly fight the other, but they each want the other to collapse, which is why NATO is crushing Russia with sanctions.


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

[User]
General Zod and his gang make terrible supervillains because they should be able to beat Superman every single time. CMV.

I haven't seen the new Superman movie yet, but Superman winning against General Zod and his lackeys always bugged me.

It's three "supermen" with military and combat training of a futuristic world versus one superman without military and combat training. I mean, either one of General Zod's lackeys should be able to crush Superman like a white belt versus a seasoned MMA fighter. A part of me has always wanted to see General Zod or one of his lackeys go all crazy- knee to the balls, eye gouging, fish hooking brawl versus Superman, and then KO him out like they should be able to. Also, tricking the leader of a global coup d'etat of a more advanced world and his two military trained followers into walking into a room of red light is lame. So lame.

Because General Zod and each of his lackeys should overpower Superman, Superman can only win through some deus ex machina, which is why they make terrible supervillains.

[Assistant]
>Because General Zod and each of his lackeys should overpower Superman, Superman can only win through some deus ex machina, which is why they make terrible supervillains.

Lex Luthor is probably Superman's best known arch-nemesis. You know what he is, he's human. He can't punch Kal-el in the face and beat him to a pulp. He can't go full on muai thai on the guy. He can't do any of that. But, time and time again Luthor challenges Superman. Utterly challenges him.

That's why General Zod is also another important villain. It has nothing to do with beat up Superman or whatever. It has everything to do with pushing Superman to all of his limits. What makes Superman different from Zod is that Superman thinks, he improvises, and he tries to do everything possible to succeed. Do you realize how boring Zod would be if it was simply as easy of a story as Zod comes in and Superman and he have a Dragonball Z styled fight that goes on for hours and hours and hours. No, Zod is a great villain because he can also challenge Superman for the most fundamental reason, he's also Kryptonian.


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

[User] [Star Trek TNG] The tamaraians communicated entirely by allegory, referencing myths-historical people and places from their culture. What did their computer code language look like?

[Assistant] They likely have a more precise and typical language for matters like engineering and computer science.  All of the reference based language they use is to convey larger ideas and the more subtle context of communications.


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

[User]
Accepted a PhD position, not sure if it was the right call

So it's been my goal to get onto a PhD for the past 5 years, so I when I was offered one I decided to go ahead and take it. I didn't vibe very well with the supervisors in the interview but figured that was maybe down to interview nerves. However, I've had the chance to meet more members of the team and everyone just seems... unhappy? There are PhD students in my current lab group and, whilst they're stressed, I wouldn't describe them as unhappy. Did I just luck out with my current lab group? Is this a pretty widespread problem? It's making me second guess my decision to join the team and the doubt is screwing with my mental health a little.

[Assistant]
If you do not vibe with the lab dont do it! A PhD can be a pretty miserable time and if you do not get along with colleagues or even the PI you make your life so much harder. Also if everyone seems unhappy that is a red flag. For the future never accept a position without talking to the lab members first to get a vibe of how working there will be.
I mean you can give it a chance anyway but be prepared to run if things turn bad.


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

[User] Eli5: Why is tile always cold?

[Assistant]
Some substances like water and stone conduct heat really well. When they're hot and you touch them, you heat up really quickly, and when they're cold and you touch them, they suck all the heat out of you.

It's why a 'dry heat' isn't considered as bad, why you can catch hypothermia if you're wet in a freezing cold day, and why tile always feels more cold underfoot. If you held a thermometer to tile and hardwood they'd be the same temperature, but the tile brings your foot down to it's temperature very efficiently, so it feels colder.


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

[User] Do you sweat if you are submerged in hot water?

[Assistant] Yes. Sweating is a reaction to heat, not to lack of water on your skin. It doesn't work particularly well when submerged in water, but that doesn't stop your sweat glands from doing what usually works.


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

[User]
Does Flash Really Damage Paintings? If So, How?

Photons are massless so how do they affect paintings.

[Assistant] Their spectrum reaches into the ultraviolet. UV can interact with electrons in molecules and can cause reactions. Such reactions can bleach out some pigments. You can see that on paints or coloured plastic bleaching when left in the sunlight.


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

[User]
Is it possible for the human immune system to "forget" any pathogen after vaccination as time passes? How does this work considering that information on certain pathogens are also retained by the immune system and does this vary based on different pathogens?

If my understanding is correct, after being vaccinated, the body produces antibodies against a particular pathogen. This can offer protection to the body if any live pathogen were to attack the body.

But, and contextually in case of COVID-19, I have also read that, even after vaccination, the antibodies that target the virus drop in number with the passage of time. Contrary to this, I have also read that the immune system does have the ability to remember and retain information about any pathogen for extended periods of time. How do these two correlate with each other?

Does/Can the human immune system essentially forget the information on any pathogen after a set period of time? Is this universal to all pathogens and if not, what exactly affects this?

[Assistant]
When a person is vaccinated, a pathogen protein/inactivated pathogen/weakened pathogen containing foreign proteins is delivered into their body (or as is the case for new generation of vaccines, a pathogen's protein is produced in vaccinated person's body)

Such protein is recognised as foreign by lymphocytes: B cells and T cells; as B cell response is somewhat easier to explain and responsible for production of antibodies, we will concentrate on it.

Upon contact with such foreign proteins and with the help of other cells, B cells start to mature and attempt to produce antibodies than have high affinity for (attach strongly to) foreign proteins. Some of those B cells that succeed in producing those high affinity antibodies will become plasma cells and will produce high amounts of antibodies but will eventually stop and die without continued stimulation by foreign protein. That's why the antibody levels will fall - unless contact with foreign protein is repeated.

However, some B cells become memory B cells. Those are not very active but they do have the ability to produce antibodies with high affinity for the foreign protein once activated by a particular pathogen protein. Should contact with pathogen be repeated, they will become active and some will become plasma cells that produce large amounts of antibodies. Memory B cells may last for decades in their inactive state.

Generally speaking, it is very beneficial for us to have the ability to mount a swifter immune response in case of repeated contact with antigene. However sometimes, it's not just the memory that would be useful but also high antibody levels and they generally fall over time.

To conclude: human immune system retains the ability to produce antibodies against a pathogen for decades, but unless stimulated again, the levels of those antibodies will gradually fall.


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

[User] Eli5: Why does light travel so fast?

[Assistant]
As far as we can tell, the universe seems to have a max speed cap on how quickly anything can affect anything else. We call that the speed of causality, or *c*.

There's a fundamental property that some particles have and others don't, called *mass*. You might know it as the thing that causes the sensation of weight, or makes things hard to lift or move. Whether or not a particle has mass determines how it interacts with this universal speed limit:

* If something has mass, it can travel at any speed it likes, as long as it's less than *c*.
* If something does not have mass, it must *always* travel at *c*, all the time. No exceptions\*\*.

^(** Assuming it's in a vacuum)

Light happens to be massless, so it always moves at the speed *c*. This is why *c* is more typically called "the speed of light", even though it really doesn't have anything to do with light.

Answers to some possible followup questions:

> "Why does the universe have a max speed cap at all?"

We don't know.

> "Why is the speed of *c* what it is?"

We don't know.

> "Why does the universe have some particles that have mass, and some that don't?"

We don't know.


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

[User]
ELI5: Is there an actual method to find a number's square root?

I've never learned how to manually find a number's square root, just to recognize the common ones or use a calculator.

[Assistant]
Fit non infinite series you can try this:
The square root of a number is just the number which when multiplied by itself gives the first number. So 2 is the square root of 4 because 2 * 2 = 4.

Start with the number you want to find the square root of. Let's use 12. There are three steps:

Guess
Divide
Average.
... and then just keep repeating steps 2 and 3.

First, start by guessing a square root value. It helps if your guess is a good one but it will work even if it is a terrible guess. We will guess that 2 is the square root of 12.

In step two, we divide 12 by our guess of 2 and we get 6.

In step three, we average 6 and 2: (6+2)/2 = 4

Now we repeat step two with the new guess of 4. So 12/4 = 3

Now average 4 and 3: (4+3)/2 = 3.5

Repeat step two: 12/3.5 = 3.43

Average: (3.5 + 3.43)/2 = 3.465

We could keep going forever, getting a better and better approximation but let's stop here to see how we are doing.

    3.465 * 3.465 = 12.006225

That is quite close to 12, so we are doing pretty well.


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

[User] [Rick & Morty] If Rick and Zeep were able to create a device (from only primitive supplies) to escape from Kyles teenyverse, why cant Zeep escape from Ricks microverse?

[Assistant] Perhaps because both Rick and Zeep had been shrunk to fit. They were "unshrinking." As Zeep is at his original size, he would have to invent a device to grow himself which is different than unshrinking.


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

[User] What exactly determines mucus's color?

[Assistant]
Basically the amount of cells and proteins present in the mucus.

Clear is just water and minerals whereas green would be chock full of immune cells and potentially even the pathogenic organism. Red to brown mucus would indicate blood.

And fun fact of the day: black mucus can be caused by bismuth sulfide, a Pepto-Bismol byproduct.


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

[User]
ELI5: The game of cricket, and how/why can the games go on for days

As an American I've always been curious, but without any media coverage it's hard to understand both the rules and gameplay. Especially how games can have such huge scores and go on for such long times.

[Assistant]
The basic idea is similar to baseball, softball, rounders, and so on. One team bats and tries to score runs, the other bowls and fields and tries to get the batters 'out'. Cricket games owe their length to one simple aspect of the rules: *the batsman doesn't have to run*. They can face ball after ball from the bowler, just defending and making sure they're not put out, and waiting for the opportunity to make a great shot. Combined with the batsman using a wide flat bat that gives them more control than the round bat used in baseball, a batsman can stay in for a long time. In the long form of cricket each team bats twice and they keep batting until all but one batsman is out and can take four or five days. (In fact if the team batting last still has two or more batsmen in when the last day finishes, the match is a draw no matter what the runs scored are.)

'Limited overs' cricket matches are shorter and have become popular, such as one-day (matches last, dur, one-day) and Twenty20 (matches last about 3 hours). These all work by limiting the number of balls bowled in an inning(s), rather than playing until all batsmen are out. (An 'over' is six balls bowled).


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

[User]
Is this right? There's 48 people per square kilometer on earth. Does that mean if we stood at equal distance from each other we'd only have 20 meters in between us?

I ask because I found out the atmosphere would be a mere 8 kilometers thick if it had equal density (sea level) everywhere. If the title question is right, this is a pretty telling statistic from an environmental perspective.

We'd all have a small square of 20m^2 that's 8km tall in which we can release emissions. That's........ not a lot.

Edit: Correct answer was that we'd have a 267 x 267 m (about 880 feet) square per person. Still, imagine living inside a space that big, that's 8km tall. Would you drive inside that space? I wouldn't.

[Assistant]
Let's fact check really quick. There are 7 billion people on earth, and the earth has a radius of 6400 km - which corresponds to a surface area of 5.1x10^14 m^2

This means there is about 0.028 square miles per person, so that's 0.073 square km per person. This is about 14 people per square kilometer. Of course, most of that area is water - if you account for the fact the oceans cover about 3/4 of the planet, this number is closer to the 48 figure you described.

Anyway, sqrt(0.073 km^(2)) = 270 meters. So we'd each have a square plot 270 meters on a side if we were uniformly distributed over the earth's surface area. If we were uniformly distributed over earth's *land,* then there's about 1/4th as much area, so we each have a box about 135 meters on a side.

If you use a more accurate number for the world population or if you hold onto a few more decimal places for the radius/area, you can probably change this number by about 10%.


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

[User] Why don't spacecrafts use nuclear fuel?

[Assistant]
Some do. Some spacecraft use radioactive decay as a power source. The craft is equipped with a radioactive material, often plutonium, but some others work as well. This material slowly decays and the energy that is released in the decay is collected and used for the spacecraft. The power output of such a system is quite low, but it lasts for a long time. It's therefore primarily useful for long duration missions, such as probes that are sent to distant planets.

Actual nuclear (fission) reactors have been used as well, primarily by the Soviet Union in satellites.

The problem with nuclear reactors in spacecraft is that they can be quite complex to design and build and there is the ongoing public concern of potential fallout should a spacecraft explode shortly after launch.


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

[User] [Harry Potter] I'm a Muggle in a long term relationship with a witch or warlock. How much can I know? How about engaged or married?

[Assistant]
It probably comes out close to the wedding. Because it's likely the couple will be having a magical baby, and that should never come as a surprise to a Muggle parent.

Mommy or daddy might put the kid on a red-hot shovel.


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

[User]
[Mass Effect] Why didn't the Reapers attack the Citadel first to shut down the mass relays?

If the Reapers can blow past the Alliance fleet while simultaneously waging war with every major power in the galaxy, why didn't they just go with their usual plan and attack the Citadel first?

[Assistant] They tried that. That was the whole plot to ME1. After ME2, Shepard blew up a relay out in the edge of the galaxy that the Reapers would use to speed into the Citadel. That bought them time and forced the Reapers to go a lot slower. They eventually did get the Citadel but by then it was too late.