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

[User]
If evolution involves subtle changes in DNA structure, why aren't there more "transitional" species (e.g. more birds that can't really fly, or half-fish/half-land-creatures) alive today?

It seems like there would be an abundance of these transitional creatures, and the "end result" (species as we know them today) would be much smaller in comparison.

Notwithstanding fossils that may exist but we have not yet found, shouldn't we see many of these creatures living in the wild right now?  It seems like there should be *some* transitional species that, while their numbers are dwindling since they are at some sort of disadvantage, are nevertheless still around.

[Assistant]
All the species are transitional. The word "transitional" only works retrospectively, as we normally do not know in which direction a species is evolving, and with several species to compare.

edit:

Let's take you, and next to you your mother, and her mother and so on. If you take enough mothers, you will eventually reach a mother that looks like a small, furry animal you have never seen before. But you can see all the mothers/daughters lined up. Some have more than one child that will turn out to be different animals. Monkeys are standing closer to you, and manatees further away.

Mind that it was of course not the same individual that gave birth to different species. Imagine painting with watercolors, and from a central red you go with one brush to green and with another to blue. If the steps inbetween are as small as in evolution, you won't be able to tell them apart for a very long time.

To come back to the transitional species: each of them is - retrospectively - a transitional state. But evolution has no goal to reach, and thus no end of the transition. Yes, you are the end at the moment, but with your children, it will continue.


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

[User]
Could a person determine their location or what year it is based on the position of the stars they see?

Often in science fiction, when a ship or person is flung to an unknown location, they often use the position of the stars or either determine that they are in the past or they're in another galaxy.

Is this possible?

[Assistant]
Yes. Ancient navigators used the stars to determine their latitude all the time. The angle between Polaris and the horizon in particular can give you an idea of your latitude in the Northern Hemisphere. In the Southern Hemisphere, the angle between a particular star and the horizon *at a particular time* can give you an idea of your latitude. (Longitude is determined by the difference between your local time and the time at the Prime Meridian.)

If you were somehow flung into the far future, you could get an idea of what year it is based on which constellations are visible at which time of year, something that changes over time. This is caused by a phenomenon called "precession", which is a fancy way of saying that the Earth wobbles on its rotational axis. (This happens to be why your astrological sign isn't what you think it is -- most astrologers use a date scheme that's many centuries out of date.)

Also, the stars move relative to each other over time, which causes distortions in the constellations. If you know the positions and velocities of the stars in a given year, you can extrapolate what year it is currently based on the difference between where you observe the stars to be and where they were in that other year.

Finally, if you found yourself in a random place in the galaxy that was still within the sphere containing all the major stars in all the constellations, you could triangulate your position based on the known positions of those stars relative to the Earth, and where you observe those stars to be in your sky at your current location.


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

[User]
[Terminator] Why do some terminators scream when they're about to die?

Like the T-1000 in the molten metal and the T-X when it was going to blow up.  Are they raging out?

[Assistant] Terminators are programmed to simulate human behavior in all its forms, although their ability to do so is hampered by the pre-settings of their chips. The only human behavior that is limited is stuff that would impact their mission (I.E, morals/emotion.) Since the mission is already failed at that point, the restrictions don't apply.


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

[User]
ELI5: Why is Braille not just bumped out letters of the alphabet?

I'm pretty sure it's just because it would take up too much space, but am not sure.

[Assistant]
That was the old system, before braille.

Braille was specifically designed because the old system was near impossible to read for blind people. The similarities between letters like G Q O C were a massive annoyance, and placed a limit on how fast you could actually read.

In contrast, the easily distinguished individual dots were a huge improvement.


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

[User] [MCU] What happened before Avengers Infinity War that led to Stark's incorporation of nanotech into his armor? The earlier Iron Man armors are advanced technology, then there's a leap to the armor being almost magical. Is there a reason for this incredible leap in technology?

[Assistant]
Tony Stark's greatest limitation has always been his own lack of motivation and ambition.  For most of his life, he did the bare minimum he could to maintain his position as a billionaire playboy. He improved the Extremis in one night while drunk.  And based on Stane's interactions it doesn't seem like Tony wasn't that involved in the day to day business activities while at the same time the scientist working for Stark Tech, recognized that they weren't on par with Tony.

It wasn't until Afganistan that Tony gained any focus, but at that time he was only going up against Earth-based threats.  The first few challenges he faced were people using derivatives of his own technology.  He didn't need to innovate that much yet.

The next big push was the Invasion of New York, which showed him that there was a much bigger universe and larger threats.  His reaction was the Ultron Project, this required a significant work but also ended up being a major failure.  This left him back at square one while also his conversations with Thor further convinced him of the need for better weapons.

And this is what leads to the nano-tech, Tony was now focused and eager to create something powerful.  Tony always had the capacity to create nano-tech he just never had the drive to do it.  But, once he had the motivation to sit down for a few months/years creating it wasn't an issue.


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

[User]
CMV: People who claim *insert musician/band here* saved my life are almost always exaggerating and statements like this trivialize suicide.

As a big music listener, I constantly see references to certain songs "saving" people's lives. For example, comments on music videos on YouTube as well as Hopeless Records' series of compilations titled "Songs that Saved My Life". I can only imagine the majority of these claims aren't sincere / literal.

In my opinion, statements such as this greatly downplay the seriousness of suicide and are disrespectful to genuine suicide survivors. Whilst promoting discussion around mental health is important, portraying depression and other mental illnesses as "cool" is problematic and should be stopped.

[Assistant]
> portraying depression and other mental illnesses as "cool" is problematic and should be stopped.

They're not saying "depression and suicide are cool". They're saying it's cool how music can resonate with people, carry a message and encourage someone to keep going through seemingly hopeless times in their life.


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

[User]
Given the extreme difficulty of unifying Gravity with the other three fundamental forces is it not likely that it's just a completely unrelated phenomenon?

As I understand it gravity is a fairly stable deformation of spacetime (or, possibly the cause of the deformation, I'm unclear on the specifics), while the other three forces have no similar effect. In fact it seems to behave completely differently from the others, and to me this suggests it isn't similar enough to be unified (seems like suggesting that a rope and a phone call are similar because they can, given the right circumstances, be used to move an object closer to me). Why, then, is there such a strong desire within the physics community to unify them? Or (and I consider this far more likely, given my relative ignorance on the subject compared to actual physics researchers) am I completely missing something?

[Assistant]
As is always the case in research, we don't know in advance how things will work out, so certainly the quest for unification is driven by aesthetics.

However, there are scientific similarities that can be found among the forces.  For example, all the forces we know of are founded on what are called *local symmetries*---the equations of motion are left unchanged by transformations that can vary from point to point in space and time.  Furthermore, it is known that if you take gravity in a higher number dimensions and reduce it to the world we know (3 space and 1 time dimensions), the resulting theory looks like gravity as we know it in 3+1 dimensions plus some additional things, and those additional things naturally appear as gauge theories, the same class of theories that our models of the strong, weak, and electromagnetic forces fall into.


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

[User] ELI5: Does colorblindness affect the functionality of old-school 3D glasses?

[Assistant] Its not seeing in red or blue that makes the glasses work. Its the red or blue light being stopped by the lenses before it ever hits the eye. This splits the combined image into two separate images.


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

[User]
[Robot/Empire/Foundation] In over 20,000 years of Galactic History, Spacer tech of robots and life extension never re-appeared across Galactic culture. Why?

There was a huge culture clash between the the first interstellar culture, the Spacers, which started out in the 21st century, and the Settlers which came 1500 years later.  Spacers viewed Settlers as declasse and vulgar,  and Settlers viewed the Spacers, genetically engineered to live over 400 years, as effete and decadent, hopelessly dependent on robots, and had a great dislike of Spacer technology.

Eventually the Settlers won out and the Spacer populations either died out or were absorbed into Settler populations.  But the Settler wave of immigration started around 3500 AD and the Galactic Empire was founded around 12000 AD.  By that time, the conflict between the Spacers and Settlers was ancient history and the Spacers were all long gone.  The Galactic Empire lasted 12000 years before the Foundation, and by that time even the existence of Earth was a lost, forgotten memory.  During this time, it was explicitly stated that not even the Emperor of the Galaxy had access to life extension.

So in over 20,000 years of time and technological advancement, none of the tens of thousands of worlds of the Galaxy, during pre-Empire, Empire, or Foundation times,  ever re-introduced either robotics or life extension?  How did this not happen?

[Assistant]
R. Daneel Olivaw is why.
Seeing what life extension technology did to the Spacers, Daneel was convinced it was in humanity's best interest that such technology not be used.
From there he is compelled by the Zeroth Law to manipulate human affairs such that the technology never gets redeveloped.


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

[User]
When I donate blood, I sometimes wonder:  What happens if the blood recipient is allergic to something I recently ate?

Do the allergens make it into the blood stream or does the digestive system destroy any molecules that could create an allergic reaction?

[Assistant] Food allergies typically act on tissues the food encounters before digestion, such as the oral and esophageal mucosa, resulting in swelling or rashes of the throat leading to constricted airways. Once the food enters the stomach the allergens are broken down before entering the bloodstream, so blood to blood transmission of allergens is minimal.


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

[User]
ELI5: Chinese Politics; how does it work?

I'm a Westerner who hears so many conflicting things about Chinese politics. I like to think I understand the US political system pretty well but the Chinese one I don't understand at all. Is it communist? Is it capitalist? Is it democratic?

Maybe this is the wrong kind of question for ELI5. I don't think most five year olds even know what politics really is. But if someone could try and explain it to me that would be great.

[Assistant]
The Chinese government is probably best described as market-Leninism. The economy is fairly free market and capitalist with private citizens allowed to own property and even start their own businesses. The government however is still very similar to the original political system devised by early revolutionaries like Lenin. The government is completely controlled by the communist party from the village to the national level. The party has 3 main responsibilities: personnel, propaganda, and the PLA.

Unlike the US where the US military is the military of the US, the PLA is not the military of China, but is rather the military of the party. As a result the military becomes very powerful politically within the party, something that would never happen in the US. Chinese leaders must have the full backing of the military in order to be effective.

The party is also responsible for controlling the media. The Propaganda Department controls how much coverage should be given to certain topics. For example lots of press coverage was given to the Senkaku/Diaoyu Islands standoff with Japan while protests in Tibet are pretty much ignored.

The party is also responsible for overseeing the appointment of all officials and positions of influence. All personnel decisions must be made with the approval of the Organization Department.

In terms of policy making, the most powerful organ is the Politburo Standing Committee, which is made up of 5-9 party members each responsible for one thing, who then make decisions based on consensus. The National People's Congress (Chinese Congress) is theoretically the most powerful but mainly serves to simply approve everything the PSC does. Occasionally they will make mediate any sort of policy differences/conflicts between different parts of the party.

The most powerful person within the PSC is the Paramount Leader (Xi JinPing) who also holds the office of President, General Secretary of the Party, and Head of the Central Military Commission. He's the most powerful person in China and the person who hold the most power and influence but his word is not the law (as it was back in the Mao era). He must cooperate with the rest of the PSC and party.

Finally there is the State Council, which is headed by the Premier (Li YuanChao) which administrates everything by issuing directives/orders, drafting bills for the PSC/NPC, and balancing the budget. The State Council is where the party and the government fuse together.

tl;dr there are 3 branches: The party, the government, and the military. The party's decisions are made by the PSC (headed by the President/Paramount Leader) with the approval of the NPC. The government is embodied by the State Council, led by the Premier, and is responsible for administrating everything and putting everything together. The military is the PLA, which is responsible for keeping order and its support is also needed by the rest of the party.


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

[User]
Does Earth have the most varied elemental composition in the solar system?

On the surface, Earth looks like a very diverse planet compared to the monotone wastelands of the other planets. However, I wonder if this translates to actual elemental diversity, I.e. a relatively high standard deviation of atomic number.

[Assistant]
If you don't count man-made elements, Earth is pretty typical for the inner planets in our solar system when it comes to abundance of elements.

During the birth of the Solar System, the orbits of the inner planets was too warm for *volatile* molecules like water and methane to condense. Thus, Venus, Earth Mars etc have a lot more compounds with high melting points, such as metals and rocky silicates, since these compounds clumped together during accretion while the volatile compounds continued to float around until the were captured by the high gravity planets forming in the outer solar system.

The terrain looks diverse because earth's gravity is strong enough to keep an atmosphere, and the temperature is *just right* for water in the atmosphere to be liquid some of the time. This liquid water forms oceans, causes erosion, and makes it possible for life to form. Those oceans, erosions and life is what provides the zest or color to our landscapes.

For a look at what the elements in earth would look like without water or an atmosphere, just look at the moon. It's a monotone wasteland with pretty much the exact same elemental abundance as the earth.


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

[User]
CMV: You either support the troops, or you support war. You can't support both.

As we continue to see our veterans be treated poorly (or not treated at all) by the VA. I remind myself of all the "Support Our Troops" slogans that were plastered everywhere just a few years ago. It makes me think that people really don't care about the toll war takes on soldiers and their families. What they actually support about is war itself, because 'Murica.

I honestly believe that if you truly support the troops, then you should actually SUPPORT them when they are in need. I feel we have an obligation to as a country.

When I hear people say "Support The Troops", I ask myself if they truly support the men and women who fight for our freedom, and their families, and if they would do what they could to help a veteran in need. Do their lives and well being actually mean something to them? Or are they just supporting the fact that we are in war?

Seeing the way our vets are being treated now, it makes me feel like you can either support our troops, or you support war, but you can support both.

[Assistant]
>It makes me think that people really don't care about the toll war takes on soldiers and their families. What they actually support about is war itself, because 'Murica.

That's why the slogan is "Support Our Troops" not "Support Our War" , the statement suggests you think about the human element not just the ideological/political reasons for the war.


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

[User] Why is Qualcomm able to hit 5nm but Intel is stuck on 14nm and amd is still pushing 7nm?

[Assistant]
I think there's a huge dIfference between x86_x64, and ARM. Also Intel manufactures their own chips in-house, while qualcomm (and AMD) use external parties. That basically means that all required machinery and tooling already exists and is primed, meaning qualcomm and AMD 'just' need to engineer the chipsets, then have them made at whoever has the tech to do so.

Intel needs to buy all their own tools/machinery/factories.

Why intel won't just find a 3rd party, i don't know. But it's nice to see them bite the dust for once.


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

[User]
Why do planets further from the sun receive less energy from its light? How does 'empty' space diminish this energy?

I was researching the factors that influence the surface temperature of planets and I was expecting to find that atmosphere composition (greenhouse gases and what not, Venus as an example) was the main factor, but it turns out the most important one was distance from the sun. How can light traveling through 'empty' space lose energy?

[Assistant] Imagine you build a spherical shell around the sun, just bigger than the sun itself, and that the shell is absorbing all the incident radiation. Each square-meter of this shell would be receiving a very large amount of power from the sun. Then imagine you double the radius of that shell. Now, because its surface area is four times the size but it's still receiving the total output of the sun, each square meter receives one-fourth that which it was receiving when the shell was smaller. Now imagine you expand the shell even more, so that it has the same radius as Earth's orbit. Now the total output of the sun is divided among a *very* large area, so each individual area is not receiving nearly as much energy. So the light isn't losing energy, it's just getting more spread out.


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

[User]
If chimps held slaves would we be morally obligated to intervene?

Let's say there were chimp castes and those at the bottom were treated horrendously.

[Assistant]
Look up the moral status of animals. A defender of the integral moral status of animals would claim they have the exact same rights as us. And if we are entitled to not being enslaved, and obliged to stop human slavery, it follows that we'd have to stop it.

Others believe animals have no rights, or at least not the same as humans. In the first case there'd be no moral obligation at all to stop chimp slavery, and in the first, a possibility of so.

It's interesting how the act itself suggests animal moral worth, especially for those that deny it. Many defend this moral anthropocentrism, the thesis that only humans have moral worth, by grounding moral status in rationality. And since humans are the only animal with an obvious rationality, it follows that they are the only ones with moral worth.

Still, some (like Descartes, famously) denied any kind of sentience to animals, usually for theological reasons (though whether or not that is his case is debatable). He famously insisted animals do not have souls and therefore do not perceive anything. A wounded dog only seems in pain, but it is a mere organic automaton.


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

[User]
[Harry Potter] Is Fiendfyre a difficult spell, difficult to find a teacher for, or something else?

I find it very strange that the only person to use such a powerful spell in the entire series struggled with his magical studies and showed no particular aptitude for casting spells compared to his peers.

[Assistant]
No.

Fiendfyre isn't a difficult spell, not in terms of ability. Crabbe cast it, and he was thick as two bricks. It does require a bit of magical power, which Crabbe has through practice if nothing else - he can manage a Killing Curse, which according to Crouch requires a fair bit of power. Fiendfyre is a monstrously powerful spell and easy enough to learn. It makes up for that by being ridiculously dangerous. Crabbe died casting it. It consumed the entire Room of Hidden Things in minutes. It is simply too dangerous for anyone without enormous willpower and control to cast, if they have half an ounce of sense.


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

[User]
Would the assembly of the ISS have been cheaper if the NASA used traditionnal rockets instead of the shuttle?

I have been hearing criticism toward the shuttle for being terribly inefficient, yet I also heard others claim it was great for assembling the station.

[Assistant]
Almost certainly.

It's a simple comparison of cost per launch, to payload deliverable to LEO per launch. At around 50K pounds of lifting capacity to 450,000,000 per launch we can say the Space Shuttle spend about 9,000 dollars per pound it pushed into orbit. By contrast, the Saturn V could throw over 300,000 pounds to low earth orbit, and cost around 110,000,000 dollars per rocket(186,000,000 if you consider the total program costs). That gives us a *much* lower price of a mere 367(620 with program costs) dollars per pound lifted into orbit.

The Space Shuttle was a marvel of engineering, but from a cost-benefit perspective it sucked.


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

[User]
ELI5: How can such a small dose of medication have such a huge impact in the way our bodies work?

I take some medications prescribed by my doctor. These medications are all prescribed in milligram doses ... when you take into consideration Im a male of 190lbs, I just cant fathom that such small quantities can have such drastic effects on how my body functions. Another example: I hear on the news the rise of drugs laced with Fentanyl and that all it takes is a few grains to kill you. How is this even possible?

[Assistant] This question is wildly broad, since the mechanism of action for various substances can be wildly different. But metaphorically, it's the same way you can demolish a high rise without explosives on every wall. We think of our bodies as a distinct unit, but they aren't. They're huge conglomerations of various systems. You don't need to affect everything; you just need to affect one special piece of a given system.


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

[User] Why does salt water dehydrate you when salt helps you retain water?

[Assistant]
Part of the problem is, seawater is really salty, about 3.5% salt by weight. An 8 oz (227 g) serving of seawater contains about 8 grams of salt. That's a lot of salt! The recommended maximum per day for sodium is 2.3 grams, which corresponds to 5.8 grams of NaCl table salt, about the same as in 1 teaspoon.

By comparison, bodily fluids like blood serum, cytoplasm, or interstitial fluid, are only about 0.9% salt by weight. When seawater comes into contact with cells in the intestines, where water is usually absorbed, osmosis pulls water out of those cells until the concentration is equal on both sides of the cell walls. So for every 8 oz serving you consume, your intestines want to supply 31 oz of water to equalize the concentration of salt.

So right there you're going to have problems, but in addition to your body dumping a bunch of water into your intestines, it's also going to absorb some of that salt and put it into the bloodstream. Your kidneys will be like "Whoa! Too much salt!" and try to get rid of it. But the only way they have to get rid of it is to concentrate salt into your urine, and they can only make that a little less salty than seawater. That means they're going to have to get rid of water to get rid of salt. They're expecting you to resupply your body with freshwater, and they don't have a backup plan when you don't do that. So now you've got diarrhea and your peeing too much, and you're probably vomiting too - you're probably going to die of dehydration.

When eating salty foods, it's a different story, usually. The mix of liquids and food in your intestines isn't going to be nearly as salty as seawater, so your body will be fine with just absorbing the salt and the water. But if you eat a lot of salt, it's still going to want to pull water out of your cells, so your cells end up a little dehydrated unless you drink a lot of liquids. So then you get a lot of liquids in your blood, and you get high blood pressure. Then your doc prescribes a diuretic so you'll pee some of that extra water out, and the salt you ate along with it.


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

[User] ELI5: Why does the iPhone require a passcode after restart if the fingerprint scanner is secure?

[Assistant]
As was made famous by the FBI/Apple confrontation from last year, recent iPhones do a pretty decent job of encrypting all content stored in the phone.  The way the encryption works is that the *master key*the big, 256-bit secret number that's required to decode the phone's contentsis never stored in the phone's permanent memory, but rather reconstructed when it's needed.  Reconstructing the master key requires two pieces of information:

* The phone's secret unique ID, stored in the processor when it is built;
* The passcode selected by the user.

The fingerprint scanner cannot be used for this, because it's an *inexact* scanner that doesn't produce the same result twice.  It's like taking two photos of the same personyou can recognize that it's the same person in the two photos, but the photos won't be identical.  But reconstructing the master key requires an exact matchsomething that's possible with a passcode but not with a fingerprint scanner.

So the phone uses the fingerprint scanner to reduce the frequency at which you'd need to reenter your passcode.  The phone can only use your fingerprint to let you in when the master key is available in temporary memory.  Restarting the phone loses the content of the temporary memory, so you must reenter the passcode.


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

[User]
What constitutes "excessive parental criticism"?

Hello friends,

I'm studying the aetiology of social anxiety disorder and excessive parental criticism is listed as a possible factor in my lecture, as it undermines self-confidence. Does anyone know to what extent *excessive* criticism would be? Its probably hard to say but how frequent is excessive?

Another related question: Is criticism in jest still considered criticism in a context such as this?

Thank you!

[Assistant]
Criticism is different from guidance. Parents should guide, not criticize.

Jest has double meaning, and thus require a certain level of advanced processing to decode. Age and intelligence is a big factor here.


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

[User]
[IronMan 3] How does Tony Stark's new armor work?

Sorry for the vague question. What I want to know is how does Tony's armor become front loading, rear loading, even able to eject him and release only his leg? Its not nano-tech is it?

He enters his armor sometimes from the front, sometimes from the back... how does that work?

[Assistant]
He gave each bit of the armour its own independent processor. Up to the Battle of New York he had to attach bracelets to his wrists in order for his armour to find him and suit him up.

Realising that this was a problem Stark upgraded each piece of armour so that it could work independently of every other piece. That way, if he was ever falling off a building again getting at least enough to let him fly would save him from crashing, even if he didn't have the full suit.


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

[User]
[general fantasy] Why do undead have trouble crossing moving water?

From all I've heard, moving water terrifies them.  and they need solid earth of some kind beneath their feet.  This implies many different things.  But why is it so?

[Assistant]
It depends largely on the undead, but a great deal of the relation between Vampires and running water likely stems from the early tradition of baptizing in a river, in emulation of John's baptism. Rivers becamme a symbol of holy cleansing.

Other possible explanations derive from a Vampires association with the Earth (resting in and depending on the earth of their burial site). Water is particularly potent and element against Earth, and the Vampires are weakened by its rapid movement.

As for other undead... Running water can carry a great deal of force. Maintaining the cohesion of Zombies or Skeletons could be difficult if something is always tearing forcefully at them.


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

[User]
[MCU]How do Hulk's pants stay on?

In comics, Reed Richards made pants specifically for Bruce, so where does he go for all his pants?

[Assistant] In the Battle of New York, luck that they stretched without breaking.  Though the pair he was wearing before the battle got removed and/or destroyed sometime between the SHIELD jet he was tearing up exploding and him landing and reverting to Banner.  After that, Stark designs pants meant specifically for Code Green situations.


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

[User]
ELI5: Why are mosquitoes more active at sundown?

I go outside on my front porch for smoke breaks at all different times of day and night. Since mosquitoes in Texas are nothing unusual I do get bitten when I go out but I've noticed in the very late afternoon, early evening around sunset there are more of them. If I go out at late at night, dawn, morning or early afternoon I get a bite or two. I go out around 6-9 or so and I'm a buffet. Why?

[Assistant] Their skin is really thin, so thin that the sun kinda dries it out and it's not good for them to be in the full sun, but when the sun goes down, it's nice and moist and they can fly around without the harsh sun harming their fragile skin.


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

[User]
[MCU] If the president of the United States is blipped in IW and replaced, who gets to president when he/she comes back?

I imagine that in the interim either the VP will step in, or within 5 years time an election might have actually been held. But assuming the president rematerializes on some toilet in the White House, what happens next?

[Assistant]
The term of the President runs for four years from the Inauguration, regardless of whether or not the person elected is actually *serving* that office every day of it. A Blipped President is, effectively, a Dead president, and that means the VP is sworn in as President to serve out the remainder of the term (or whomever is senior-most in what's left of the line of succession). If the administration declared the blipped President to be officially dead, then the successor is sworn in *as* President, and is President for the rest of the term, whether or not the "dead" person somehow miraculously returns to life. If the administration decides that the blipped President isn't quite *completely* dead, but is instead just "missing", then the cabinet (or whomever is left) signs a letter assigning the powers of the President to the appropriate successor as "Acting President" (this is what happens when a President is incapacitated, such as being in surgery or a coma). This preserves the option of returning said powers to the proper President once the "disappearance" has ended.

But, regardless, the term of that particular presidency ends four years to the day after it starts. So when President Disappearo suddenly reappears five years later, it doesn't really matter. They're no longer President, by any legal measure, and haven't been for quite some time.

So when they rematerialize on the toilet in the White House, they're politely informed of the situation and escorted off the premises. Or, well, the very nice and appropriate version of that. But they're not President anymore.


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

[User]
[Black Mirror: Bandersnatch] Spoilers: A question regarding the fate of one of the characters.

In the timeline where Colin jumped off the balcony, and then later went AWOL at work in a future play through, did Stefan kill him? The show doesn't give a definitive answer on Colin's fate, other than Stefan mentioning he saw Colin kill himself in a dream.

In universe explanations, please. :)

[Assistant]
i dont have an answer but he doesnt come back if he jumps and you reset to before that so maybe he's not dead if he didnt come back, and he remembers the first convo the way it happens the second time *even if you didnt go there*

i bet he's either the demon or he's at least a self aware "questgiver" npc since he doesnt seem to have any autonomy but he's aware through timelines.

has anyone mapped the scenes he's there for?


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

[User]
[LotR] How does Aragorn claim the throne of Gondor if Isildur abdicated?

Didn't Isildur abdicate the throne of Gondor to his nephew Melindil prior to heading North to rule over Arnor?  If so, how does Aragorn, a descendant of Isildur, have a claim to Gondor?

[Assistant] Isildur never abdicated. Just as his father, Elendil, committed rule of Gondor to himself and Anrion while ruling as High King of both Arnor and Gondor from the North, so did Isildur commit rule of Gondor to Meneldil while he traveled North to rule as High King. The right of rule over both Gondor and Arnor as High King technically passed to his son Valandil, but effectually it ceased to exist (except for a failed claim by the last King of Arnor, Arvedui) until Aragorn came along and reasserted it some 3000 years later.


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

[User]
Does the government know about the Men In Black?

In the first movie, it was said that the Men In Black is funded independently, and not part of any government branch. And it's obvious that law enforcement has no clue about them because we saw them mind wiping people in the NYPD building. So does the government know about the organization or is it just that covert? I don't recall them ever talking about contacting the president, and their own members are even forced to forget about it after reaching an age of retirement (Some time in their late fifties it seems, unless they get promoted to a position of leadership). So I guess my real question is: does anyone but the MIB know of the organization's existence? (I mean actually knowing for certain of their existence, because I know the movies established that they were kind of an urban legend, but let's not count that).

[Assistant]
At one point the government *did* know about the MiB. They began as a poorly-funded organization in the 1950s, one which few took seriously, until the Baltians made contact.

Baltian First Contact occurred on the night of Thursday, March 2nd, 1961 when a group of Baltian refugees landed on Earth just outside New York City. They came here on a mission to establish Earth as an apolitical neutral zone for aliens in need of a planet to relocate. This meeting became a cornerstone event in the formation of the Men in Black.

The MiB have since severed any connection with the US Government on the grounds that they were too intrusive. Not too long after, the Baltians left Earth for reasons not given and their current whereabouts remain unknown.


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

[User]
How does animal testing really work?

I was thinking about it and realized that Ive got a lot of preconceptions from my teen vegan years (Yeah, I used to be that guy). I still think were unnecessarily cruel to animals in many ways but definitely no longer trust PETA as a reliable source. So, does the US government really require new shampoo products to be poured over cute bunnies eyes before entering the market or is that just BS? Can anyone enlighten me on when and why animal testing is necessary leaving the moral discussion aside?

Thanks in advance.

Edit: Thanks for the responses, guys! Im all for medical testing, which I understand covers the vast majority of animal experiments. Im still against cosmetic testing, regardless of how the suffering is minimized, but it was nice to hear from people who work at the labs and learning that they do care about their animals.

Also, for the record, I wouldnt trust PETA to take care of a plant.

[Assistant]
I dont know the specifics for shampoo. But for animal research, before any experiment you need to write up a proposal that dictates why the animals needs to be tested, and the measures you will take to do it in the safest way possible, using the least number of animals. You also need to show why it is imperative animals need to be used, and the good that will come out of it.

It is Incredibly regulated, and scientists take great care to do it the best way possible. At the end of the day animal testing saves lives by providing necessary medication and vaccines that would not be available without it.


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

[User]
ELI5: if an identical twin get children, and their children take a DNA test, will it say that they are half brother/sister?

I mean they don't get children together, but they both get a partner and then get children. (No game of thrones)

[Assistant] In short, yes. Since identical twins have the same DNA, their offspring will then have DNA that suggests that they share a same parent. This emphasized even more if a set of identical twins have kids with another set of identical twins, in which case a DNA test will identify them as full siblings (with respect to genetic similarity).


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

[User] ELI5: Why do some pictures look like they are sharper and better than real life?

[Assistant]
Real life has so much extra visual information that cannot be filtered out, which can distort the way things appear. For example, glare, unpolarized eye structure, differential strength between a person's two eyes, varying iris apeture, and most importantly, varied visual ability person to person.

Cameras can filter out glare to make an image sharper. They can enhance color and brightness to correct for ambient light variations, they can used polarized lenses to reduce distortion from horizontal reflections etc.


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

[User] ELI5: What happens to dust particles that get in to the eyes and lungs?

[Assistant]
If they truly get deep into your lungs, they may become trapped there, but that's a relatively hard place to reach. Most are caught before then in mucus lining your airways. Tiny moving cilia work in concert to gradually move this mucus towards your throat, where you either swallow it or cough it out.

Dust in your eyes is flushed out with tears, either onto the face if the irritation (And the crying) is great enough, or by draining into your nasolacrimal duct into the back of your nose/throat.


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

[User] How can mercury be so dense, yet still be a liquid?

[Assistant]
The density of a substance doesn't necessarily correlate to its physical state of matter. For example, solid water (ice) is a solid, but it's actually less dense than liquid water because of the "honeycomb" structure that water molecules adopt when forming certain types of ice.

So, just because something is less dense doesn't mean it should be a liquid or gas.


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

[User]
[Bright] How would you safely test someone for Bright powers?

According to the film, touching a magic wand with your bare hands will definitely tell you if you're a Bright... only problem is you'll will fucking *explode* if you aren't one. Is there any other means of testing a person for Bright abilities that doesn't involve the chance of dying horribly?

[Assistant]
Based upon the one dude interrogated by the feds, Brights are somewhat recognizable by folks.

He pegged the one cop as special after only a few moments with him.

So while holding a wand is a 100% answer, there are other methods known to magic users and their followers.


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

[User]
ELI5:Why do companies like Google, Microsoft, apple etc largely support liberal politicians but then hide money overseas from taxes and higher cheap labor in China?

We all read about these plans like building giant barges for financial headquarters so they can sit in international waters where there are no taxes. They higher workers at the Foxconn place etc. Why do they support liberals but dodge their policies?

[Assistant] Google, Apple, and Microsoft are all publicly traded companies. Because, unlike a private company, they are ultimately obligated to provide good returns to their investors, if it's legal and it saves them money, they're obligated to do those things.


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

[User] ELI5: What's the difference between an Embassy and a Consulate?

[Assistant]
Its kind of like a library system, you have the main big library in your area and the smaller branches depending on it.

In simple terms the embassy is the main headquarters, where the ambassador lives there can only be one ambassador from a country so therefore only one embassy.

Consulates are offices of the embassy spread out in bigger cities so you dont have to travel to the embassy, they provide the same services but slower at the Consulates because they usually send or forward the paperwork to the embassy.


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

[User]
ELI5 how a moon pool (aka wet porch) works, and why a ship with one doesn't sink.

I know it must have something to do with water pressure, but was hoping for a concise ELI5 answer to understand it more easily. Thanks.

[Assistant]
There are a few different kinds of moon pools.  The easiest one to understand are basically a hole in the floor above the waterline of a drilling platform or ship with multiple hulls that lets you look down into the water.

You're probably thinking of moon pools below the water line though.  Imagine taking a cup, turning it upside down and then pushing it under water.  You will have trapped some air inside the cup.  The water wants to get in the cup, but it can't make a lot of progress because the air is taking up the space (the air does compress a little).

Now imagine drilling a hole in the side of the cup while its under water.  Obviously the air will leak out through the hole, and the water will rise to a bit above the drill hole.

This is how moon pools work, except that the hole in the cup is an airlock that keeps all of the air from escaping.  While the air is kept in place, the water cannot enter.  If the moon pool were turned sideways, or had a hole, it would indeed fill with water.


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

[User]
ELI5: Why is it so hard to dispose of trash?

Hear me out... earth has trash I know and it piles up. But how? The trash was MADE on earth and its still on earth. How is there not somewhere to put it like where things were previously mined?

Isnt there technically less stuff on earth now than before mankind now that weve sent up a bunch of satellite and other rocket-related space junk? Isnt there room where the elements of the now space junk was originally located to put current trash?

[Assistant] The problem with trash is that **nobody wants to spend any money on it**.  There are fine, safe, approaches to recycling and storing it.  However, none of those things makes money - except aluminum can recycling.  So, somebody would have to pay.  Local governments don't have money, and raising taxes to process trash more isn't popular because taxes isn't popular.  Do you want to sort and dispose of trash for no paycheck?  Neither does anybody else, nor are there companies that want to truck it to a mine or store it in the mine for no money.  Most of the plastic in the ocean doesn't come from the countries that use the most plastic bags and straws, it comes from countries that throw trash in their rivers.  Trash isn't a trash problem, it's a money problem.


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

[User] [Pokemon] If mewtwo is a clone of new, why does he look more like an evolved form of mew and not mew?

[Assistant] Mewtwo isnt a perfect clone. Before it was actually born, its embryo was tampered with to modify its DNA. After being born, there were further gene-splicing experiments performed on it to make it more powerful.


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

[User] [General Fantasy] Why are werewolves most allergic to silver?

[Assistant] Alchemists used to associate different metals to different planetary bodies. Gold for the sun, iron for mars, copper for Venus. Guess what metal is associated with the moon? So if the full moon makes a werewolf transforms, it's possible that direct contact with the 'moon metal' breaks that connection. Then you're just a dude that's been shot and you die.


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

[User]
[LoTR] I'm an Maia by the name of Giorfin. When I arrived in Middle-Earth 300 years ago some guy called me Biam. Now every few decades some new person gives me a new name. I've got like 40 names now. I've noticed that a ton of people have a ton of different names. What the hell gives?

Why does everyone keep getting new names all of the time? My buddy Olrin got to Middle Earth a long ass time ago and some guy randomly gave him the name Gandalf.  Now he's also known as Mithrandir, Incnus, Tharkn, Greyhame, Stormcrow among many other names and designations.  This other guy Aragorn is also called Estel, Telcontar, Thorongil, and Strider.

That asshole Morgoth is also known as Morgoth, Bauglir, Belegurth, Belegr, Arun, and Mbelekor.

Why the hell can't people seem to stop giving each other like 30 names?  I'm immortal for Eru's sake!  Do you know how many people I'll meet in even a century?  How the hell am I to be expected to remember that King Bill also goes by Crongar, Thork, Mallgaeter, Halfnark, Quignar, and Steve??

[Assistant]
That's it exactly. You're immortal. Languages change, you remain the same. Even if you build a tower and never leave, every few generations of men and elf there's going to be another group wandering through and calling your something else. Sure, you could put a sign up - but the sign is going to be in Quenya A or something and the fucking Noldor are going to start mispronouncing things, and then some Man in a bear shirt is going to roll over and just start calling your "Bright Lord of Morning" or something which will get totally butchered in translation when he tells it to the Dunedain ranger he's sharing a pint with at the Dancing Pony.

And that's before you meet the *poets*. Kennings are just de rigueur in Middle Earth this century. You're lucky to get through a cocktail hour without six new sobriquets.

But look on the bright side: the time of the elves is fading, the memories of Men grow dim, and vellum only lasts a couple centuries. Hide out long enough and they'll forget your old name and you can just introduce yourself all over again.


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

[User] [40k] How could someone get recruited into the Inquisition/become an Inquisitorial Stormtrooper?

[Assistant]
You are very good at your job.

Inquisitors see... *promising* soldiers, they then *recommend* them to the Schola Tempestous (totally mangled the name), who then trains them alongside the other Stormtrooper candidates. They pass then get shipped off to their inquisitor... assuming they dont die.

Inquisition generally the same, find someone you like, recruit them.

On the other hand the Scholas, schools for the orphaned children of officers are prime recruiting grounds as they provide Sororitas, Commissars, Inquisitors, Stormtroopers and clerks. Just take your pick of the thousands of malleable children ready for your... education.


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

[User]
ELI5: If singers can perform others' songs, why can't comedians use jokes from others?

With proper acknowledgement, like in the beginning of the act the comedian would explain there will be jokes from others, maybe even list the originator of the joke.
After all, I just want to be entertained, do I really care from whom the joke came from specially if I never heard it?

[Assistant]
When a singer performs another person's song in public, or records and releases that recording to the public, the songwriter not only gets written credit but also gets payments over time at rates based upon the sales of that recording or performance.

When an honest comedian uses other comedian's jokes, the honest comedian has purchased the right to perform those jokes. Nearly every comedian has purchased jokes, and most will tell you where they came from if asked.

Most recent discussion has been about a female comedian who did not purchase the rights to some jokes, and then used them in a performance AND made money from that performance. That's the problem.


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

[User]
[starwars] what's up with chewbakas laser cross bow?

Is there laser arrows or something?

[Assistant]
At base, a bowcaster is literally a crossbow. As in, functionally identical. It uses a string and high tension rods to propel a quarrel downrange.

Specifically though, a bowcaster has a few key differences.
Instead of a "string" it uses a very high tension wire.
Instead of just relying on the potential energy of a flexed rod, it uses magnetically polarized orbs to boost the force applied to the quarrel.
Instead of a simple sharpened metal bolt, it fires an short metal rod that is charged with plasma - as it exits the bowcaster, the physical projectile is sheathed with high energy plasma that greatly increases destructive force. These projectiles are also generally charged with impact detonated explosives.

It's the traditional weapon of the Wookie's. Typical bowcasters are manually drawn and require incredible strength to do so. Chewbacca's was equipped with an autococker.

They're much more powerful and destructive than blasters, trading limited ammo and cumbersomeness.


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

[User] ELI5: How does GPS work in smart watches/phones? Who gets paid by companies making these in exchange of gps services?

[Assistant]
GPS is just a signal sent from satellites, end users are not sending a signal back. It's much the same as tuning in a radio station, that is "free" as well (just paid for by advertising mostly).

In the case of GPS, USA taxpayers are the source of the funding.


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

[User]
ELI5: Why is two weeks notice traditional when quitting? Why not longer/shorter?

My first thought was that it gives the company enough time to replace you but, that seems super arbitrary and not nearly long enough for a skilled position.

[Assistant]
It's long enough for a company to replace you, but also short enough for the employee to wrap up any truly urgent things, say their goobyes, not have to deal with (too much) hostility or coworker retaliation for quitting (if applicable).

If an employee wants to quit, it's usually because they're not satisfied with their workplace or they found a better position elsewhere (which implies the current position is unsatisfactory in comparison). Dissatisfaction often means reduced productivity, so it's a good thing for an employer to only have to keep them that extra 2 weeks.

Plus, if an employee feels their workplace does deserve more than 2 weeks, nothing prevents them from hinting around beforehand or even working with the employer to ensure a better transition.


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

[User] ELI5: what happens inside the body when athletes get a 2nd wind?

[Assistant]
Your body doesn't want to exercise.  Your body gets whiny and says, "We're tired, let's go lie down under a tree and take a nap."

Then you push through and your body says "Fine, if you're going to be that way, let's go nuts!  Let's really kick those glycogen fires up, let's throw some fat on there too."

Now you have a timer running.  That time is your glycogen stores.  You only have so much until your muscles are out for a while.  That means you can only burn fat which is piss-poor for intense energy.

That's where you "Bonk".  You feel it when your muscles kind of start to feel limp and week, you're a little nauseous, and you could eat all the pancakes in the world.  It's the pancake thing that gets me.

Now you're done with anything like sprinting or high intensity for a while.  You can keep pushing but it takes time for your muscles to rebuild glycogen.  Eating lots of carbs before and during the workout helps.


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

[User]
ELI5: Why do bows have a longer range than crossbows (considering crossbows have more force)?

EDIT: I failed to mention that I was more curious about the physics of the bow and draw. It's good to highlight the arrow/quarrel(bolt) difference though.

PS. This is my first ELI5 post, you guys are all amazing. Thank you!

[Assistant]
Crossbows have a big disadvantage due to having short limbs compared to a bow. This is true for all types of bow, but it has to be balanced with how unwieldy it would be to have a huge longbow or crossbow.

The biggest difference is the length of the power stroke. A fairly typical archer will have a draw length (the distance between the drawn string and the back of the bow) on their bow of about 27-31 inches, and a brace height (the distance between the undrawn string and the back of the bow) of about 6-8 inches. This gives you a power stroke of somewhere in the 19-25 inch range. Most crossbows have a power stroke somewhere in the 9-13 inch range. That dramatically reduces the amount of time the string is imparting force on the arrow. That's how you can have an arrow flying the same speed as a bolt despite having a much lower draw weight.

There's also a penalty in efficiency for having short limbs that affect crossbows. All bows have a draw force curve that shows how much force the string is imparting compared to how far it is drawn back. In a typical longbow, this curve is shaped like an upward facing banana. That means that when it is barely drawn, almost no force is imparted, and as you draw it farther the force increases more and more. The flatter the curve, the more efficient because the force on the arrow isn't dropping off as much during the power stroke. Having longer limbs gives you a flatter curve, which is why longbows are so long. So, the crossbow with its very short limbs has the force drop off very quickly, giving less speed for the same amount of force.

Finally, since crossbows need to have a lot more initial force to make up for the inefficiencies we've already talked about, they have to have shorter, thicker, heavier bolts so the initial shock of the force doesn't destroy them. Heavy bolts also need more fletching to straighten their flight path. The short, thick bolts are much less aerodynamic than the longer, skinnier arrows.


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

[User]
[40K]What's to stop the Tau from becoming a major superpower?

The Tau don't seem to have a major flaw like the Eldar or the Imperium (Eldar have a declining population and the Imperium has stagnant technology) so what's to stop them from becoming one of the most powerful factions?

[Assistant]
Numbers.  What the imperium lacks in development it makes up for in bodies.  You have battle Mechs that can challenge space Marines?  Ok here's 50 guard battalions.  Deal with that.  Maybe they're not as well equipped but artillery is artillery and they'll eventually will through shear weight of numbers.

You have an Armada?  That's cute, because imperial have world's have local militia navies with more ships.

The only thing the tau have going for them is that they're not on the radar of the imperium as far as xeno threats.  Once they are?..... They'll be crushed under the millions of guard corpses that the imperium will find at them.


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

[User]
[Terminator franchise] Due to some space-time anomaly, all the terminators and humans that have been sent back in time arrive during the original terminator movie. What happens next?

What would the original T-800, Uncle Bob, all the Kyle Reeses, the T-1000,T-X, the T3 T-800, Pops, and so on do in this situation? Is Sarah Conner worst off or better off now?

[Assistant] Each terminator acts according to its initial programming, to kill or protect SK, which leads to a huge battle royale in Downtown LA. The total mayhem it would involve would draw the attention of the authorities and the army, which would eventually succeed in neutralizing and capturing at least a few of the terminators. Dyson/Pentagon acquires the tech much sooner, Judgement Day proceeds with gusto.


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

[User] ELI5: How does buying a house "build equity"?

[Assistant]
Lets say a house is worth 250K. You borrow 230K and put down a 20K deposit. You now have 20K equity in the house. It's the value of your holding minus your debt. As you pay down the mortgage, your equity percentage rises until eventually you own the house. If the prices have remained stable or risen, you've also gained a paper profit that you can realize when you sell.
The process of paying off the mortgage is what builds the equity.


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

[User]
ELI5:Why is it that if you shape your mouth like an "o" you breathe cold air but if you shape your mouth like a "0" you breath warm air?

The title is self-explanatory.

[Assistant]
An "o" mouth forces the air to move out faster than an "O" mouth.

Both kinds of air technically have the same temperature, but the "o" breath is moving fast enough to evaporate moisture on the skin, causing it to feel cold.


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

[User]
Can a brain completely deprived of sensory input perceive time?

I wonder, with no outside reference, if the human brain has way to tell that time has passed. I have heard that people in sensory deprivation tanks lose track of time, but what if, somehow, no sensory input made it to the brain at all, would it be able to perceive the passing of time?

Thanks, Science is Awesome <3

Edit: (Question I asked in comments) What if I lost all sensory input for an incredibly short period of time, sub-millisecond, would I notice or would that millisecond just cease to exist for me? Memories are built upon sensory input so wouldn't that time be lost like moments spent in sleep?

[Assistant]
You can, you'd just be really bad at it. See: Campbell, S. S. (1990). Circadian rhythms and human temporal experience. In R. A. Block (Ed.), Cognitive models of psychological time, (pp. 101-118). Hillsdale, NJ: Erlbaum.

I think where you're going wrong is that memory is *not* dependent on external sensory input. Repeat a word over and over in your head and pretty soon, you have a new memory with no sensory input.


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

[User] What changes in our cells as we grow older that makes it more difficult to recover from an injury?

[Assistant] A part of it is that we have fewer stem-cells ready to take the place of any damaged cells. As we grow our initial stem cells take find their homes and begin specializing. We always have a certain number of stem-cells in our bodies, but fewer as we age. Also, each time a cell divides it loses a link in a chain of "telomeres". After it loses all its telomeres it will stop dividing. Obviously as we age, fewer cells are replicating themselves to replace damaged ones. Under normal circumstances you don't need your cells to keep diving except for maintenance, so this is expected behavior, but can lead to longer recovery times from injury.


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

[User] Why do you not feel hungry after not eating for a long time?

[Assistant]
In short, adrenaline and cortisol. If you haven't eaten in a long time, your body doesn't relax, it instead increases stress hormones which induce the metabolism of energy stores (ie, fat tissue, glycogen) and help mobilize you so that you can find food or fight for it.

Once you eat, stress hormones decrease, blood flow to the intestines and visceral organs is restored, and you feel hungry again (this is why appetizers induce appetite).


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

[User]
CMV: If a leader is democratically elected, the people are absolutely to blame for the bad things he or she does either domestically or abroad

People always talk about how people are different from politicians, and you are not supposed to judge a person based on what their politicians do. However I would argue that this is simply a tactic used to avoid responsibility. I do not want to point fingers at specific countries in my actual post, even though I will probably do so in the comments anyway, so my apologies if the names of these fake countries sound cheesy to you, but anyway, here we go anyway. Imagine the following hypothetical scenario:

The people of Awesomeland elect President X, who wins by a landslide. Then, President X makes some very unpopular choices domestically, and many people say:

It is what it is, its not up to us.

Yes it is, you specifically gave him power.

But OK, to make up for his shitty domestic choices, President X now invades Evilstan. A lot of Evilstanjans are killed by airstrikes and Awesomeland soldiers. Their economy is crippled by sanctions.

Yet the people of Awesomeland will argue, that the average Awesomelandian should not be blamed, because theyre just people.

In reality, no. Every single Awesomelandian who voted for President X now has blood on his hands.

Again, not directly naming any countries, so as to not get shit in the comments.

[Assistant] This really depends on the electoral system. In the USA, the Electoral College determines who is President. Most states allocate their electoral votes to the candidate that wins the plurality of the votes in the state. That means if you vote for candidate X and the plurality of your state voted for candidate Y, then all the voting power of your state goes to candidate Y despite your vote. Even if candidate X wins overall, your vote did nothing to put them there because all of the electoral votes from your state went to candidate Y.


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

[User] ELI5:When I touch my face while I am looking mirror, which one my brain perceive first? touching or seeing?

[Assistant] Follow up question: would the answer be different if someone else touched your face?  When we touch ourselves, our brain knows we are about to touch ourselves so perhaps it recognizes the sensation "ahead of time"?


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

[User] Where does the light go when you turn off the lights in a room with no windows?

[Assistant]
Scattered and absorbed.

Nothing is perfectly smooth so there is a lot of scattering.

And anything with color will absorb some light.  So it all scatters and absorbs over and over until it's all "gone"

A good question is what happens in a room with nothing but mirrors  (spoiler: mirrors diffract and absorb a little bit too, so same thing)


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

[User]
ELI5: How is therapy effective when it is in the therapists' financial interest to keep you as their patient?

Same goes to other medical fields, I guess.

How can a doctor make you better when their job requires people to be sick?

[Assistant]
Aside from the personality types looking to get into these fields of work there's two objective factors that would make it a bad idea to prolong treatment and they kinda go hand in hand: supply and competition.

Many therapists have lines of patients waiting to get appointments and if you have a bad reputation they will go somewhere else.
This is also the case in countries with free healthcare, but there you also have the added reason of costs.


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

[User] ELI5: What exactly happens to muscles when you massage them and why is it good for them?

[Assistant] Massaging reduces the production of compounds called cytokines, which play a major role in inflammation. Also, it stimulates mitochondria which helps convert glucose into energy used for cell repair and growth. Massage causes microtrauma also, which stimulates nutrient flow to the targeted area and speeds recovery.


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

[User] Could there be an island of stability somewhere further down the periodic table?

[Assistant] Do you mean further than the island of 104-118? It might be possible that the same mechanism of completing a closed neutron shell stabilizes even heavier super heavy elements around 126-164. Or it might not. You'd be a very famous person if you could prove it one way or the other!


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

[User] [Resident Evil] What was the Umbrella Corporations master plan with the T-Cell virus and zombie apocalypse after all?

[Assistant]
Pretty sure Umbrella Corp on the surface was just trying to develop new bioweapons to sell to world governments, while the various Management heads were seeking out the "cure" for death so they could do what all billionaires dream to do: live forever and never lose their money.

All the apocalypses are just a result of their piss poor planning in some cases, and direct results of their warfare application experimentation in others.


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

[User] ELI5: What makes the iron in food stuff like spinach digestible in our body? How is it different from consuming small quantities of iron directly?

[Assistant] It's really not different. It's a common grade school experiment to take some iron rich cereal or something and spin it in water with a strong magnet for a long time and you eventually end up with a bunch of stuff that is just iron filings stuck to the magnet.


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

[User]
[Doctor Who] When The Doctor regenerates, do his personality and morals change?

Right before 10 regenerated, he says he doesnt want to go. When 11 regenerated he says Ill always remember when the Doctor was me.

It seems to imply that his current self dies with each regeneration. What about him (apart from physical appearance) actually changes when he regenerates?

[Assistant]
Personality: yes. Morals: Kind of.

His "core values" don't change, but everything around them does.

The doctor will always be willing to put himself (or herself now) in danger to protect innocents.

But his favorite food, book, song, time period, etc. That all changes when he regenerates.

Now, what he finds acceptable to do may change between forms.

There is some conflicting evidence regarding his memories but it appears on the whole he keeps them from form to form.

Think of it kinda like a hardrive you put in multiple different computers. What it looks like from the outside and how it does things might be slightly different, but it still has all the same information.

Make sense?


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

[User] ELI5: How are unwitnessed behaviours (such as an adult bird building a nest the chick never saw the construction of) passed onto the next generation?

[Assistant]
Nest building is a species-specific innate behavior, birds dont learn how to build a nest, theyre born with an instinctual drive that lies in their genetics. Its also why different species make different types of nests which be radically different in construction.

For a contrast, brown bears are NOT born knowing how to fish, they have to both learn from their mother by watching her, and also they develop their own unique style. Each bear fishes in slightly different ways, some like to wait under the water, others prefer to wait at the top of a fall for a fish to practically leap into their mouths, others wait behind the boil of the fall to pick up fish that failed the jump, some use jaws first and others use paws.


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

[User]
CMV: Bitcoin mining using non renewables should be banned immediately.

Global warming is a serious threat to the survival of the human species and it's insane we are adding to this problem for no good reason. Currently Bitcoin mining consumes more power per year than the whole country of Argentina. There would be hardly any downsides in banning the mining of crypto currencies using non renewables and the benefits would be immediate.

Even with a 'carbon tax' mining for bitcoins should be banned immediately if it's being done using non renewables. There is no effective way to capture carbon at this point and it's unclear if there will ever be.

What am I missing?

[Assistant]
They are buying this energy legally. They are paying for it. Producer of this energy will still produce that energy and sell it to others. So what is the point of that ban?

That "dirty energy" will still be there, the only change will be distribution - BTC mining will start getting fueled by renewables and renewable energy that were used for other purposes will be used to mine BTC. At the same time, "dirty energy" that were used to mine BTS will be used to supply those who aren't supplied with renewables anymore, because that energy is being sold to BTC miners.

Your proposal solves nothing. It will make BTC mining "cleaner" by making other energy uses "dirtier".


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

[User] ELI5: Why are Windows, OS X, and Linux the main operating systems out there? Why are there no newer operating systems?

[Assistant]
there are many others.   those 3 are the big consumer OS's.   there are many other backend industrial OS's that are still in use like VAX.

Linux is a branch of the *nix family of OS's.  Other members of the *nix family include the BSD branch, the Solaris branch, the AIX branch, among others.   There are many many published flavors of Linux in its branch,   Redhat, Gentoo,  Centos,  Ubuntu, etc.      Other branches have multiple members as well,  FreeBSD, OpenBSD, NetBSD, etc.

It takes alot to make an OS.   you need not only the working core, but you need vendor support.    The Linux branch in its infancy had quite a problem with consumers because no vendors published hardware drivers for it, because there's not enough market share of consumers.  it's a catch 22.


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

[User]
[ALIEN] whats the purpose of the spooky chains and water room?

I just saw this a few hours ago, and I dont get why a cargo ship has a spooky chains and water room.

to specify the room I am talking about, when one of the engineers (Im bad with names) goes after the cat, and he gets to this room he looks up at the water and lets it drip all over his face.

[Assistant]
The chain hangs from an industrial rail-crane. Its purpose is to help lift heavy objects, when the ship is in full-g. Since the ship is a longhauler, there is probably a lot of heavy equipment to lug around.

This would be epecially important in a water room (which is essentially an internal water-tower) since such a room would be much taller than its width, pretty much a shaft with a water tank in it.


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

[User]
ELI5: Why can't we remember dreams very well?

I sometimes wake up and remember entire dreams, but five minutes later I completely forget what it was about. Why is this?

[Assistant]
Think of your head being like a computer. There's permanent memory in hard drives and then there's temporary memory in the RAM.

The permanent memory is kept but dreams is temporary data and gets flushed out when you close the program which is sleep. You can remember them if you try and focus kind of like saving but if you don't they're useless ramblings of your brain and get thrown out.

Someone please go more sciencey on this I'd like to hear the big fancy words behind it.


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

[User] ELI5: How did Germany become one of the richest countries in the world after losing two world wars and having to pay huge reparations and recovery costs and having the country split into two.

[Assistant]
Germany is ideally positioned to become astronomically wealthy.  That's also the reason it fought 3 major European wars in less than 75 years - all its neighbors realized that was true and tried to put a stop to it.

Germany is centrally situated in Europe, has access to the sea, and has great river connections.  Germany can service markets across Europe from its central location.

Germany has access to both iron and coal which means it can make steel and generate power without having to import anything.  The coal/steel complex centered on the Alscace/Lorraine area is the proximate cause of friction between France and Germany, and placing that region's resources into the European Coal and Steel Community laid the foundation for the European Union and also helped keep both country's economies steady after WWII.

The Germans have a fairly homogeneous culture (barring a lot of immigrants from Turkey in the post-war era).  That culture stresses values of hard work, thrift, education, and collective action - a perfect storm for creating successful companies and industries.

The Germans came out of WWII with a destroyed infrastructure but a lot of smart people.  With the help of the Marshall Plan they were able to rebuild the infrastructure and the smart people worked with great diligence to restore their material wealth.  Germany had a pre-war reputation for making high quality goods and German companies traded on that reputation in the post-War era; making things like cars, industrial equipment, chemicals, cameras, etc.

The German people have had a very stable political system since the war.  Debates in German politics are very centrist - the difference between the party of the Left and the party of the Right are of degree, not of substance.  When reunification became possible the West Germans mobilized quickly to make it happen, and deployed a lot of money to smooth the transition.  There was relatively little objection in German society to the reunification even though it was expensive.

tl;dr:  A resource-rich, geographically central country, with a population of people with the right values to be successful and a political system that is very stable.


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

[User]
ELI5: Why do some medications cause weight gain?

In the case if you are eating normal amounts of healty food as you were before the medication? Isn't your body starved of energy if all is stored in fat tissue?

[Assistant] Some medications greatly increase hunger. Others make you feel more lethargic, making you less likely to exercise, or making your exercising less effective. And some can actually affect the process of how your body burns calories, or how they store and absorb sugars and other nutrients.


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

[User]
[Marvel] Why is Galactus humanoid, in armor, and muscular?

He looks like some normal supervillain on earth, in a costume.

He has armor on but he will never encounter anyone to defend against physically.

He's jacked, but just sits in space all day.

[Assistant]
He's not. That's just how he appears to you, because it's easier for your mind to be afraid and in awe of a 40 foot tall jacked dude in purple cosmic tech armor.

And if that doesn't have the suitable effect, the crust of your planet cracking soon after usually cements the desired response.


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

[User]
When nucleons bind to form a nucleus, does each nucleon "retain ownership" over its quarks (is each nucleon a truly unique entity)? Or is it possible for quarks to swap from one nucleon to another? Or does it not make sense to talk so exactly about them?

I was reading about the strong force and color confinement recently, but everything I read seemed to only talk about an isolated nucleon.

A brief reading of the Nuclear Force (the binding force between nucleons) which can be viewed as a "residual strong force" indicates it is mediated by virtual mesons.  To my completely uneducated mind, that reads as though the nuclear force is almost like nucleons swapping quarks between one another (as a meson is a quark-antiquark pair).

I'm assuming I'm reading too much into it and letting my uninformed imagination run a bit too wild.  Because my loose understanding of virtual particles is that they're just a byproduct of random fluctuations in the quantum fields.  But then that makes me think that maybe it doesn't make sense to say that a nucleon has "ownership" over its quarks at all, if its quarks can't really be distinguished.  Which only furthers my question of if each nucleon is clearly a separate entity while in a nucleus or not.

[Assistant]
In short: Yes nucleons can exchange quarks via mesons, but because of confinement the baryons will always have three valence quarks.

But all, e.g., up quarks are indistinguishable. So it makes no sense to say that a particular quarks left the proton and travelled to another (as part of a pion for example). At the same time a new up-quark must have been created and remained in the original proton.

And then there is the issue of energy scale. The quarks are still bound inside the nucleons, meaning the energy required to get one out is larger than the random energy fluctuations in the system (= temperature). That is why you only exchange virtual mesons rather than real particles. Mathematically this makes it convenient to describe the nucleons as their own things that than interact with one another, rather than looking at all the quarks and gluons and whatnot separately.

You can create states of matter where the quarks are no longer bound, i.e. it makes sense to model things on the quark level. It is called "quark gluon plasma", and it exists at much higher energies/temperatures. E.g. it is created briefly in particle colliders, when you smash nuclei into each other.


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

[User]
ELI5: Why do muscles sometimes involuntarily twitch?

Im laying on my futon and my left quadriceps starts to twitch on its own accord. Made me curious as to why.

[Assistant] Usually that's an electrolyte imbalance (sodium, potassium, magnesium, etc). Your body runs on electricity and those ingredients help transfer that energy by making the blood more/less conductive. So when you have very low amounts of these your legs twitch because they are forced to construct from an intense signal that under good balance would not be a strong enough shock to "wake up" the muscles. That's why momma told you to eat a banana if your legs hurt (potassium).


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

[User]
ELI5: The end of the Lord of the Rings

Where are the elves, Gandalf, and Bilbo going? Why does Frodo have to go? Thanks.

[Assistant]
The story takes place at a crossroad where the age of elves and magic is dying out and the age of man is emerging.  Lothlrien and Rivendale are two of the last bastions of elven magic in the known world, overall it has been waning and dying out as elves leave.   With the rise of the kingdoms of man the remaining elves led by Galadriel and Elrond decide to pack it in and migrate to Valinor, or the "Undying Lands" and leave middle-earth to to man.

Frodo is so much in agony due to being wounded by the Nazgul, he is also just totally spent by carrying the ring all that time.  The elves allow him to come with them.  His friends are distraught over this but in many ways understand.


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

[User]
[Star Trek] [Voyager] Capt. Janeway's decision to ally with the Borg against Species 8472

I'm wary of asking this, since it skirts the borders of objective fact(in the Star Trek Universe) but here goes:

TLDR: My core question is this: was Capt Janeway sufficiently justified in believing that Species 8472 were a comparable threat to all galactic life as the Borg? After a single violent encounter, with a single individual of the species, she deigns them a greater threat than the entire Borg Collective. And thus justifies an alliance with Borg, where she helps them fight off Species 8472. This seems at odds with various Starfleet norms, not least being the Prime Directive. Am I missing something or disregarding some facet here?

I've been rewatching Star Trek: Voyager recently and I've just finished the episode VOY 4x26: Hope and Fear. In that episode, >!the last survivor of an alien race - recently obliterated by the Borg - attempts to trick Voyager's crew and sacrifice them to the Borg. He does this in revenge for Voyager helping the Borg overcome Species 8472 - a conflict they would have otherwise likely lost.!< One particular line was striking - "Who were you to make that choice? A stranger to this Quandrant!", and it echoed a like from Chakotay one season ago (in VOY 3x26: Scorpion) , where he says - "How much is our safety worth? We'd be helping a species guilty of killing billions". At the time and later Janeway points to what Species 8472 did to her crewmember Harry Kim and the psychic visions transmitted to another crewmember Kes warning "The weak will perish".

But this seems a rash judgement in my opinion. I assume 8472 are new to our universe and their initial contact, possibly sole contact before the crew of Voyager, was with the Borg - an antagonistic species if ever there was one. Voyager's crew encounters one of their pilots in a derelict Borg cube, in the wake of a large battle, where he attacks Harry Kim and infects him with a unique "virus". But this doesn't seems to have been a deliberate act, but rather a feature of their biology. Their subsequent interactions, including psychic threats, are after Voyager has allied with the Borg. Looking at these actions as those of soldiers and field commanders in a warzone, it seems a stretch to characterize the whole species. Imagine if the Klignon's were judged solely by their warcrys and battle prowess?

Furthermore, consider how Starfleet has interacted with other inscrutable, violent forms of alien life. For example, the Crystalline entity in TNG - a creature with a far higher Federation body count than 8472, but they still attempted to establish communication with it rather than kill it.

Finally, I would consider the Prime Directive applies here. Since Species 8472 has made no overt threats towards the Federation or Voyager, this seem like a purely internal matter between them and the Borg. Simply because the two species involved are as advanced(arguably more so) than the Federation, does not preclude the non-inteference that is the foundation of Star Fleet. To interfere is to change the natural course of history for both species, and in fact for all species in the Delta Quadrant.

Thus I submit that it seems to me to have been the wrong choice going by Federation principles and indeed the general principle espoused by Star Trek as a whole.

[Assistant]
The facts available to Janeway after the initial encounter with 8472 but before entering negotiations with the Collective were:

* 8472 is advanced enough to be a major threat to the Federations most powerful adversary.
* 8472 have shown themselves to be hostile when they attacked a Starfleet officer.
* 8472 have fired upon a retreating Federation starship without provocation.
* 8472 Have threatened to purge the galaxy (i.e. kill everything).
* Borg generally don't kill but rather assimilate.
* Borg assimilation is reversible (Locutus/Picard).

It is perfectly reasonable to conclude that 8472 is a more pressing threat than the Borg.

The PD certainly doesn't apply, it ceased to be an internal matter when 8472 fired on Voyager.


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

[User]
[DC] why aren't a lot of batman villains considered terrorists

You would think after all the biological weapons that joker, scarecrow, and poison ivy have used in their attacks on Gotham. The us government would probably go black ops and have someone like Walker to take them all out. Before you say their insane so they can't kill them do you think that would matter to groups like the CIA and FBI groups that plenty of shady business before.

[Assistant]
> The us government would probably go black ops and have someone like Walker to take them all out.

Oh, the irony...

Waller is probably 80% of the reason the feds **don't** smoke super crooks. Where most folks see a problem, she sees opportunity; an ever rotating array of disposable, deniable superfreaks who can make shit happen and take all the heat for it. Waller keeps the maniacs and weirdos in play because it serves her purposes.


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

[User]
ELI5 - Please explain this economics to me, I just can't wrap my head around it

 This is a common math problem that floats around the internet in many forms but I just don't get it.

1. I borrow $50 from person A
2. I borrow $50 from person B
3. I buy something for $97 leaving $3 change
4. I repay $1 to person A leaving $49 owing
5. I repay $1 to person B leaving $49 owing
6. I keep $1 for myself
7. I now owe $49 each to persons A and B making a total of $98 owed and I have repaid $2 total ($1 each to person A and B)
8. $98 owed + $2 paid = $100 that I initially borrowed
9. How the f\*\*k did I magically get to keep $1 from seemingly nowhere?

[Assistant] You're looking at it all wrong.  You started with $0.  You borrowed $100, which brought you to -$100 net worth.  You bought a $97 widget.  That left you with a $97 widget and $3, with a total debt of $100.  You paid $2 on your debt.  That left you with a $97 widget, and $1 in cash, and a total debt of $98.  Thus, you have assets worth $97+$1=$98, and debts totaling $98, which is the same as the $0 net worth you started with.


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

[User] ELI5: Why do weightlifters looks fat rather than just pure muscle?

[Assistant]
To build muscle, you need to lift weights and eat a calorie surplus. The extra calories allow you to grow -- both muscle and fat.

Body builders then cut -- they stop eating as much, but keep working out, to reduce the fat.

But for weightlifters, the cutting is just a waste of time. It makes more sense to keep eating and keeping building muscle. (Mind you, they need to cut a bit, they can't get so fat that it gets in the way, but they don't need to be crazy low fat like body builders).

All the same muscles are there, they just aren't as visible.


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

[User]
CMV: Playing video games as a single hobby without interacting with the community is way better.

Basically the older I get the more I realize how annoying and obnoxious the video game community is at times.

This isnt everyone by the way, but from the past 10 years of meeting different people in the video game community, the wide majority of them are obnoxious and uninteresting people.

Im not saying Im special either, as Im a fairly boring person but I like that about myself. I find playing games as a singular hobby way better them interacting with the general public.

Is this an unhealthy mindset to have? 9 times out of 10 I dont find the majority of gamers interesting to talk to.

[Assistant]
> how annoying and obnoxious the video game community is at times.

It really depends on the game and community.  Some games have really toxic communities.  Other games like Kerbal Space Program and Factorio have wonderful communities with very little toxic behaviors.  It also will depend on which part of the community you encounter, for example, a game's modding community, fanart community, fanfiction communities, or speedrunning communities are going to be a very different slice of the community.

There are lots of players just like you that want a mature community, and in many games all that is required is finding a guild of like-minded people.


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

[User] ELI5: Why is it hundreds of stars at night can be seen from Earth, but videos/picturs of astronauts in orbit never have stars in the background (it is just black)?

[Assistant]
It's about exposure.

A photo from Earth at night looking up has probably nothing in the frame other than stars.  This means the camera can keep the shutter open for a longer period like 10 seconds, allowing dim objects like stars to be visible.

Videos and pictures of astronauts have an astronaut in the foreground.  The camera is exposing for the astronaut, probably at a shutter speed of around 1/200th of a second.  This is too short to see any stars except maybe the very brightest few.


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

[User]
[supernatural] What fraction of deaths are monster related, and why haven't epidemiologists noticed?

Supernatural has had 30+ monster species each of which must propagate either by sex or by turning new people. Each must feed on a schedule, and most feed on humans in some way.

For each species to continue it must have one or more members. Given the number of monsters they've killed, there must be thousands of total monsters in the us at any time. Why haven't epidemiologists started to notice the patterns of vampire or werewolf related deaths? How many monsters live in the US at any time, and how many people do they kill?

[Assistant] Hundreds of thousands of people go missing every year in the US alone. Those people are just part of that number. When you consider that like most predators, vampires and other terrible things that go bump in the night tend to go after the most disenfranchised and vulnerable members of society, it's no surprise that epidemiologists are unaware.


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

[User] ELI5: Why can't Windows accurately predict file transfer times?

[Assistant]
Disk drives have on-board memory or "cache" with which to smooth out data transfers. Data is often at various places on the disk, and there needs to be time to swing the reading arm and head around to find the right place to read it from the disk. There is also the matter of when the data is read the disk is spinning by at great speed; the computer isn't always ready to accept the data from the disk, so it needs a buffer area (the cache) to put it in the meantime.

This means that drives exhibit "burst" speeds when reading and writing. If you wanted to save a file your computer could say "save these memory addresses!" and dump them directly from your computer's random-access memory into the drive's cache very quickly. Slightly later the drive actually gets around to positioning the heads and writing what is in the cache to the platters of the disk itself. However, if you have a lot of data to save it will eventually overwhelm the drive's cache and it will be forced to stop just storing it in the cache until it can work through the backlog.

What this means is that when Windows looks at how quickly a file is being written by the drive it gets confusing results. The first few bits of the file are being accepted extremely quickly so it thinks it will finish the transfer very quickly, but after a little while the drive seems to slow down significantly. Now something it looked like would take 10 seconds is taking a minute. If you tell that drive to do other things too that minute could be come two, or even three!

Ultimately, the timer included in the box by Windows isn't going to be very smart. It only compares the clock to the rate of data transfer, which often doesn't consider the whole picture at all.


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

[User] ELI5 How did they manage to get big ships docked before the invention of motor engines ?

[Assistant]
The first thing to do is wait for the right weather. You anchor outside the harbour or sail around until the wind is of the right strength and direction to allow you to get in.

The next thing to do is take on a pilot, this is someone who knows the harbour intimately and so where to turn, where to avoid shoals etc. You pick them up out at sea where there is space to do so.

Then you sail into the harbour and up to a quay. You need to control your speed by adjusting and taking in sails so that you berth slowly. This is quite within the capability of a skilled skipper and well drilled crew.

Then if you need to move the ship to another basin, another quay, turn it around etc then you warp it around, which basically means pulling it about using ropes. You might have mule teams to help, certainly you use capstans on the ship and ashore.

Steam tugs were used long before ocean going cargo ships were powered by engines. They could help manoeuvre the ships into tight spots, or tow them into harbour in calm weather.

All of the same techniques are used in modern shipping with modern ships, in fact modern ships are arguably harder to dock given how much larger they are.