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

[User]
Does the DOUBLE SLIT experiment imply that we the observer can influence matter around us?

So as some of you may know, the double slit experiment is a demonstration that light and matter can display characteristics of both classically defined waves and particles. One of the conclusion's of the experiment is that through observation, we have the ability to collapse the wave function of an electron. So it's as if the electron is aware of us watching? or something like that.

Anyway, from my understanding of this experiment and its conclusions; we (the observer, spirit, being) have the ability to affect a tiny piece of matter by simply just observing.

So i ask this:

Since and electron is a tiny piece of matter and is fundamental to the structure of all our current known elements. Do the conclusions of the Double Slit experiment imply that we, the observer, may have the ability to influence/change all matter around us? Seeing as electrons are pretty damn common.

Thankyou, i look forward to the discussions that follow :)

[Assistant]
Not in the way you think. "Observation" doesn't literally mean that a conscious being looks at something. It means something more close to "interaction". By interacting with a particle in order to measure it, you influence its behavior. If you take away the humans from the double slit experiment but leave the detectors then you get the same result.

This misconception is the foundation for a TON of pseudoscience to be wary of.


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

[User]
ELI5: How does a queen ant come to be?

From what I understand, queen ants are usually much larger than other ants in their colonies and they pretty much just sit there and wait for others to bring them food. However what I don't understand is how does an ant become a queen ant? Are some ants just born much bigger than others and they automatically become queen ants? If so, why are those certain ants born much bigger than others? Or are queen ants born normal and somehow become larger than others during their lifetime and then become queen ants? It's a massive mystery to me!

Also, I guess same question applies to other species that has similar things to queen ants, like bees, etc.

Please shed some light to me on this! :)

[Assistant]
It varies widely by species of ants, but most feed a few larva some special jelly and those larva will grow to become queen.  Sometimes they'll make too many queens and the new queens have to fight to the death.  Some ants will "promote" one sterile female, usually decided by fighting, into their new queen.  In some species, the queen makes the decision whether to make another queen or not.  Some ants don't have queens.  Some Ants have lots of queens.

Ants are interesting.


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

[User] ELI5: How exactly does our body inform us that we need to pee?

[Assistant] Nurse here. Imagine your bladder being a balloon. The balloon gets filled (with urine) and when it's about half way full, stretch receptors in the wall of the balloon starts sending signals to your brain that you need to pee. When you pee the balloon empties itself, and kinda deflates, meaning the stretch receptors are no longer sending signals to the brain about you needing to pee. Bonus info: the body produces on average 1ml/kg body weight urine per hour meaning if you weigh 80 kg you produce about 80 ml of urine per hour. You start to feel the urge to pee when the bladder contains 300-400ml of urine. Bonus info 2: don't keep your bladder full too often, because the stretch receptors in the bladder tissue might get stretched too much, and get damaged, which can lead to incontinence.


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

[User] ELI5: How can hot dog buns be cut all the way through but also stuck together in the package so they have to be torn apart?

[Assistant]
The buns are baked in pairs, hence they stick together, they are then split from the 2 outside edges.

The left bun is cut along the left side and is joined on the right side. Right bun is cut on right edge, joined on left. They are rolled separately as dough, but join while the dough rises.


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

[User]
[Harry Potter] Polyjuice potion sexy times

In theory, could a man become a woman through polyjuice potion and become pregnant or could woman become a man and impregnate a woman? If so what would the results be? And how would the genetics work?

[Assistant]
>could a man become a woman through polyjuice potion and become pregnant

Not unless he took the potion for long enough for him to menstruate, have sex, and then carry the baby to term. This could have disastrous results however, as if you miss a dose during the pregnancy, you'll change back to a man, and the baby will find itself somewhere with your urethra or vas differens, an undesirable place for it to be for the both of you.

Either that our you'd just have testes where the ovaries would normally be.

EDIT: As for the genetics part, if a woman turned man were able to produce sperm, she would still only make them with an X chromosome. If she/he paired with a woman, only girls could be produced. If she/he paired with a man turned woman, either sex could result, just like a normal pregnancy.

If it were a man with a man turned woman however, there would be a 1 in 4 chance of it being a normal girl, a 1 in 2 chance of being a normal boy, and a 1 in 4 chance of being conceived with 2 Y chromosomes. A child with two Ys would likely result in a miscarriage very soon, but we don't know as this cannot occur normally in humans.


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

[User] ELI5: How do scientists at the Large Hadron Collider safely create and record temperatures of 5.5 trillion degrees?

[Assistant]
Primarily by making it happen to a very very small amount of material. 5.5 Trillion degrees sounds like a lot, but in terms of mass x thermal energy, the sample size at that temperate is so small that if you distributed all the energy there into a bucket of water, it wouldn't boil.

The LHC is aiming to create a very specific set of conditions on a very small sample.  They use a lot of energy to smash stuff together and witness high energy interactions, but it happens using a very small amount of mass.


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

[User] [Marvel] If Deadpool gets beheaded, does his head grow a new body or does his body grow a new head? Or do both things happen and the end result is two Deadpools?

[Assistant]
Generally, his head grows a new body. Deadpool's brain is the "origin" of his healing factor in that sense. It's possible that bisecting his brain and moving the two parts away from each other would result in two Deadpools, but -- **thankfully** -- no one's really tried that yet.

The only major instance of the opposite happening -- Deadpool's body growing a new head -- was with a Deadpool from a different timeline, commonly known as D**r**eadpool.


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

[User]
ELI5: What prevents the supreme court of the united states from making outlandish interpretations of the constitution?

If they secretly want to amend the constitution, and want to implement X, then why can't they just interpret one segment of the constitution as X?

[Assistant]
The Supreme Court Justices can be impeached by Congress for "bad behavior" according to law. As of now, the only Justice to be impeached was Samuel Chase in 1806. He failed to provide justice, exclusively using his position to defend his own political beliefs.

Supreme Court Justices are required to provide an explanation for their verdicts. If they fail to provide rational, well thought out reasoning in their explanation, they will be impeached for negligence.


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

[User] What is preventing Taiwan from becoming its own country? As of right now is it considered to be part of China?

[Assistant]
After World War 2, a communist revolution occurred in China and the previous ruling government in China escaped to Taiwan. At the time, the Chinese revolutionaries were incapable of assaulting Taiwan and the United States continued to recognize this government as the legitimate government of all of China, but this didn't stop the revolutionaries from declaring victory and laid claim to all lands owned by the ousted government, including Taiwan.

These circumstances didn't change much for a while, but eventually the US decided that they needed to move on and aknowledge the new Chinese government officially, but they would have no contact with the US unless they aknowledged China's full borders, including Taiwan. The US agreed as long as the Chinese didn't make too much of a fuss over the US defensive support of Taiwan from military invasion and independent trade with Taiwan.

We are left with the result where everybody officially recognizes that Taiwan is part of China, but everybody trades with Taiwan as an independent country and the US militarily protects Taiwan from China.


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

[User]
CMV: The human race will never leave the solar system

Science is amazing and it can create amazing things but unfortunately I do not think light speed will be one of those things. The closest Earth like planet we know of is 31 light years away and that is unimaginably huge.

Even if we built a space ark and set out on a quest that would take generations the society would collapse or be destroyed before it reached the destination, space is incredibly dangerous!

We as a species are doomed to stay on this Sol system

I am not saying we can make living here great just that we will never travel anywhere else

CMV: Is there hope that we can do it?

[Assistant] You're using current knowledge and speculation, but if there's one thing that science has proven is that we know so little, and one discovery can lead to what today could only be seen as miracles. Even in the past 100 years out lives have improved vastly, and given another hundred, we could potentially discover the miraculous.


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

[User]
When it comes to earth killer asteroids, is it purely due to size, or does mass matter as well?

Assuming another 10km wide dino-killer was in earths path, would it cause the same damage if it was the equivalent mass of gravel, as opposed to one single lump?

So would slamming into a 10km diameter sphere of gravel do more or less damage than slamming into a solid 10km rock?

Its the same mass of asteroid, just different size.

[Assistant]
The damage done by an asteroid impact will be roughly proportional to the kinetic energy at impact which is equal to 1/2 * m * v^2 where **m** is mass and **v** is velocity. So the damage done will be proportional to mass and the square of velocity.

I don't think it would make much difference if the object was made of gravel rather than rock. Either way most of the kinetic energy will be immediately turned into heat and radiation.


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

[User] ELI5: What was that short barrel at the end of old USB cables, and why are they gone now?

[Assistant]
it's a ferrite bead, which is used to mitigate the effects of the inductance of the wire running through it.

We don't need them nowadays on USB cables because we use better manufacturing techniques that better match the 'differential pair' of twisted wires, and better controllers at either end that can cope with a little interference.


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

[User]
[Home Alone 2] Why is the homeless lady homeless?

She says she used to have a job and a husband but the husband left her for another woman and now she has a hard time letting people into her life. That by itself shouldn't make her homeless or unable to get a job.

[Assistant] If the husband left her, he probably kicked her out so his side chick could move in instead. Or she didn't get much (if not any) money after the divorce. It's implied that she has no friends or family around to help her out so she ended up on the streets.


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

[User]
[Physics] What makes the continuous stream of bubbles from a single spot when you pour champagne/highly carbonated beverages?

I just poured a glass and often they just keep coming from a single spot for a very long time.

[Assistant] Dust or scratches in the glass provide what are referred to as nucleation sites where bubbles of dissolved gas can precipitate out of solution. It's hard for dissolved gases to escape a liquid without a nucleation site that allows bubbles to form. This is why boiling chips are used in a chemistry lab, to prevent liquids from becoming superheated and prone to explosion.


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

[User] ELI5: With so many opioids (and other ways to die of OD) around, why do death-by-injection states use chemicals that are apparently excruciating?

[Assistant]
Because they are tried, tested, and medically approved for that use. Getting things medically approved for execution is not great for PR and not procedurally an easy thing to do, so the available options are not what they could be.

With that: MOST of the excruciating part comes from poor application and dosage of the medication rather than the medication itself. The drugs we use for lethal injection are quite caustic and are easy to blow veins with during administration. Blown vein here being the equivalent of a water pipe bursting - either a full on rupture, split, or tear of the tube-like vein itself. Inserting an IV and administering medication with intent to kill isn't a particularly difficult thing compared to...keeping people alive, but this is a circumstance where the simple job needs to be done very well. These drugs absolutely punish bad to mediocre IV insertions, have very specific dosages per size, and are easy to screw up on during every step. Couple that with most/all medical profession boards considering members participating in the lethal injection to be against their ethics codes; and there has been long string of random prison employees setting up these IVs. These employees were not skilled, or even necessarily trained, at inserting IVs - because of that their lines tended to blow or they would get the dosage calculations wrong.

When an IV line blows, anything going into the body through that line now just leaks into the tissue around the vein rather than directly into the veins themselves. Caustic chemicals damaging this tissue, plus a deadly dose of medication being slowly absorbed over hours rather than minutes causes a LOT of pain and suffering.


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

[User]
ELI5: What is the point in ever having trains run between platforms at subway stations?

As someone who frequently uses the subway, I find it odd that not all stations follow the pattern of train platform train, where the platform is in between the trains so that you can access both trains going in both directions from the same platform.

Instead, there are stations that follow the pattern of platform train train platform, so you can only access one train going in one direction from each platform, and to go in the other direction you'd have to get to the other platform, usually via stairs.

I don't see the benefit in ever constructing a station like the second example. In fact I distinctly remember not being able to find how to get to the other platform at a certain station and having to take the train in the wrong direction to go to a different station where I could then change directions.

[Assistant] It's to reduce congestion so you don't have everyone that wants to go North and everyone that wants to go South in the same area. It also reduces confusion if you pay attention as the trains only access the platforms from their right so you know which direction they are heading.


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

[User]
[Transformers] Why would a faction call themselves something heinous as "decepticon"? Doesn't it imply deception and generally bring up a mental image of distrust, lie or trickery?

I mean, if that was the name they adopted once they came on earth, it'd make sense, since they're "deceiving" the humans. But since they were called that from the very beginning, I don't see get why they need a name that just sounds like a shady organisation. For example, "autobots" don't sound like either the good/bad side. Sounds kinda neutral. But Decepticon just comes off as the bad guys.

So yeah, why decepticon? I get the primary word here is deception, but...who are they deceiving? Why have a negative connotation to your name?

[Assistant]
"Sometimes deception is necessary, when those who should listen to the truth will not, and will only understand once they have been lied to and forced to see their own lies."

Megatron viewed the deception of those who were weak and corrupt as virtuous; if someone was unwilling to face the truth, the Decepticons would aid them in their self-deception and destruction.


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

[User] Is it possible that exposing deep-sea creatures to bright LED lights, like we do in wildlife documentaries, could be harmful to them or to their biomes?

[Assistant] There is always a risk of exposure or harm in exploration.   In this case, it should be a minimum, temporary disruption since it it just light.  The benefits of learning about that biome and its creatures is outweighed by the possible temporary harm.


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

[User]
How accurate are old temperature records?

I read today that temperatures in Death Valley, California hit a new record of 130 F degrees, breaking the previous 129 F record in 1913.

How accurate were temperature readings in 1913? Im assuming it has improved since then, so what is the process for doing comparisons throughout historical improvements in technology for reading temperature?

[Assistant] A basic mercury thermometer is very accurate in those ranges and can be easily calibrated using boiling water (at sea level) and ice water. More extreme temperatures would have been more challenging (though not impossible) a century ago, but the standard environmental measurements should be reliable.


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

[User]
[DC Lantern Corps] What is the difference in constructs between each corps.?

Can only Green Lanterns create artificial items of constructs? Can only red's blast? Is there a particular corps that only creates weapons? Is there a particular corps that can only create peaceful constructs?

[Assistant] All the Corps can make anything they can imagine. Red has a hard time because rage is hard to control, but we do see the leader (who's name escapes me right now) make a construct. Blue can only make constructs when green is around however, after all hope is useless without will power.


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

[User] ELI5: what is the scientific/chemical explanation for why we feel so calm when petting animals?

[Assistant]
Humans evolved to have pleasurable feelings associated with activities that are good for survival (being warm, eating energy rich food, sex etc.).  There are two of these that come with petting animals:

1) pets (especially cats and dogs) behave in ways we interpret as affectionate, so our brain thinks "this creature likes me"

2) some aspects of pet mammals (small, soft, large heads relative to their bodies) remind us of human children, so petting an animal feels like looking after a child, another activity which is good for survival of the species so evolution selects for it.

What we describe as "cute" often essentially means "resembling a human child".


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

[User] [Star Wars] From Episode 1 to 7, how many years did this cover in the story?

[Assistant]
Well.

The Battle of Naboo takes place 32 years before the Battle of Yavin.

The Battle of Endor takes place 4 years after the Battle of Yavin.

The Battle of Starkiller Base takes place 30 years after the Battle of Endor.

So, 66 years.


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

[User]
Why is the Chinese Room argument flawed?

Searle's "Chinese Room" thought experiment was used to demonstrate that computers do not have an understanding of Chinese in the way that a Chinese speaker does; they have a syntax but no semantics.

It has been heavily criticized that it is not the English-speaking human inside the room that acts as a computer but rather the room as a whole, with the human as a kind of central processing unit.

My question is why the realization that the room as a whole is more analogous to a computer relevant to Searle's argument that computers can't think? Doesn't the computer, in this case it being the whole room with the human, still lack semantics? What specifically gives the room as a whole the opportunity to understand Chinese while the human in the room does not?

EDIT: Okay, a lot of people have replied mostly explaining that it is the room's ability to speak Chinese that gives it the ability to understand it. Upon first read this seems backwards to me - wouldn't the ability to understand a language naturally give way to the ability to speak it, and not the other way around? This is just a kneejerk reaction mind you, but to me it seems like the most logical or if not most logical at least the most intuitive answer. But that doesn't necessarily mean it's correct, so I will say this:

There is this direct Searle response about the whole room (the system) understanding Chinese:
> There is no way that the system can get from the syntax to the semantics. I, as the central processing unit have no way of figuring out what any of these symbols means; but then neither does the whole system.

What about this is inadequate? The room is a machine designed to respond to questions in Chinese, not to think about the questions asked and formulate a response.

[Assistant]
> It has been heavily criticized that it is not the English-speaking human inside the room that acts as a computer but rather the room as a whole...

People do popularly give this objection, but given that it's something Searle himself has raised and discussed in the original paper, one would expect them to comment on his response to this suggestion, rather than, as is more typical, to simply offer this suggestion as if it were something he never thought of and in some supposedly obvious way trumps his case.

Though, in this case, it sounds like you have some of Searle's own doubts about this objection already in mind.


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

[User]
[Game of Thrones] What was Jaqen Hghar doing in Westeros?

Its pretty far away from his home. Besides that, he seems like basically an unstoppable force to the point that surely he wouldnt be a prisoner unless he wanted to be?

[Assistant]
Jaqen was stuck in the black cell in the red keep. Although faceless are powerful he is still just a man. The waif is killed and others can be too. And the black cells have their own reputation for being inescapable.

In the books after recruiting Arya, he continues on to old town and seems very interested in the citadel, implying that he was caught on a mission and after his escape he is continuing to peruse his target.


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

[User] [MCU] Why Asgard army from the start refused to even consider talking with Hela, that claimed to be Odin's heir?

[Assistant] Look at it from their viewpoint. Odin covered up Hela's existence, including literally covering up the art of her made at the time. For Ragnarok-era Asgardians, Thor is Odin's one true heir, with Loki being a condemned traitor. This 'Hela', whoever she claims to be, is a murderous invader who uses necromancy to raise an army of monstrosities from Asgard's honored dead. What's there to talk about? Asgardian soldiers are brave and stern, they're not going to try to appease her.


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

[User]
[Astronomy] If the International Space Station were to be completely abandoned, how long would it take before the station would be uninhabitable?

Let me clarify. Uninhabitable does not mean not operational. The station can still be functioning, it just cannot support life nativelyas in, you would need a spacesuit to stay alive.

[Assistant]
Life support systems are quite automated. The station needs supplies because it cannot recycle 100% of oxygen and water, but if you assume it is abandoned, these resources are not consumed. Oxygen levels would be pretty much constant, and temperature is regulated using solar power.

After a few years the solar panels would degrade, producing less power, and batteries that power it during eclipse would degrade as they have gone through too many charge/discharge cycles. Mechanical parts (fans, pumps, etc) wear out and become more likely to fail randomly. Electronics are damaged by cosmic radiation. Atmospheric containment is not perfect, so some air slowly leaks into the near-vacuum of space. After a decade or a few decades it may no longer be able to support a pressurized environment with a controlled temperature.

But in practice the station's orbit would decay due to atmospheric drag and it would burn up in the atmosphere long before any of that happens. We're comparing decades against months/weeks.


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

[User]
CMV The mainstream media should stop publicizing violence as much as they do

I believe that if the media would quit publicizing rallies gonna violent, fighting, and shootings (to an extent) as much as they do, it would solve a ton of problems. IMO all these shows do is show all the people who are willing to resort to violence that if they do, there message will be spread. I very rarely see stories about peaceful protests anywhere, and then those same people that support showing all violence on the news wonder why people resort to murdering others because they disagree. All these stories do is make people say Hey! I dont want to kill anyone, but if I pull a gun and threaten, I will be publicized and everyone will know about my cause. CMV Reddit!

[Assistant]
The media is filling a demand.  Whatever gets people to watch, that's what they're going to show.  They're a business like any other, and they have to make money.  They do that by making sure that people are watching their ads and clicking on their website.  Unfortunately, the way to accomplish that is by giving the most sensational thing possible.

In short, it's not their job to stop publicizing it.  It's our job to stop making that the most attractive option for them.


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

[User]
ELI5: How do we actually know what vitamins and minerals are in the foods we eat

Bananas , sweet potatoes , and squash, are all high in vitamin k. Aside from Google and health books, how can we find those vitamins and what do they look like ?

[Assistant] We have data from processing samples in a Mass Spectrometer. The sample is broken down into its chemical components and the spectrometer identifies the quantities of each chemical. So we get the exact amount for the small sample and the scientists scale up and give an educated guess as to how much for a full serving/individual food.


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

[User] ELI5: What is the difference between brightness, contrast, and gamma?

[Assistant]
These are terms relating to video, both analogue and digital.  They are settings that affect how a TV or other display device shows the video information it's receiving.  Let's say the video has the raw brightness in the range from 0 to 100...

The TV's brightness setting controls which level is considered black.  Usually the correct setting is around 6 and anything from that level or lower will show as black.  Turning the TV brightness setting up higher sets the "black level" lower which will make the picture brighter on the screen but can also reveal dark information not intended to be seen, like the sync information on analogue video.

The TV's contrast setting controls which level is considered white and is usually around 92.  Turning up the contrast sets the "white level" lower, exaggerating the difference between the brightest and darkest part of the screen but also hiding detail in the brightest parts of the image.

A TV's gamma affects how the video levels correspond to the brightness of the light coming from the screen.  You might think that video level of 10 would show 10 times more light than a level of 1 but instead, the amount light goes up according to the video level taken to the power of gamma.  If the gamma is 2, the video level 10 shows 10^(2) as much light as video level 1.  The NTSC standard uses a gamma of 2.2 and PAL has 2.8.

The reason for gamma is that the human eye can see a very wide range of brightnesses and using a power or even an exponential function to represent levels better corresponds to the way the eye works.  It gives a better quality image for a given quality of video signal.


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

[User]
[Theoretical Computing] Could a sufficiently powerful computer that has perfect observation & input predict the future?

Hypothetically...If it were possible for every electron that has a current position, and a momentum, and a trajectory...to be measured and recorded by a computer...

isn't it logical to assume that a sufficiently powerful computer could compute/predict the future? (i.e. the location of those quarks, electrons, & atoms 1 second into the future based on current position, speed, trajectory, and gravitational/electrical push/pull of nearby objects.)

The electrons are orbiting each other like the planets are, affecting one another as they pass by. Everything has a small pull on everything else. If we knew the position of every single one...could we tell the future?

TLDR: I often struggle with how free will can exist if everything already has a state. It seems to me like reality is simply an infinitely complex equation (particles rotating around one another) that **does have a hypothetical solution as to where they will be next.**

[Assistant] Current Quantum Mechanics says no. All objects on a fundamental level have an inherent uncertainty in their position and momentum. For a large scale observer (motion of planets, stars, thrown objects, etc.) then it would be possible but on the scale of individual atoms and electrons it would be completely impossible to precisely know where any of them are or how quickly they're travelling, it's determined by probabilities.


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

[User]
[Avatar the Last Airbender] How scripted are the Earth Rumble tournaments?

In the Earth Rumble 6 tournament we see several elements that are parallel to the kayfabe of pro-wrestling such as over-the-top characters (especially the foreign heel: Fire Nation Guy), gimmick fighters, and feuds between contestants being used for drama. On the other hand, I highly doubt Xin Fu could convince Toph to play along with any kind of script, and inviting the crowd to fight the champion seems to be asking for trouble. So, to what extent do you think that the drama of Earth Rumble is manufactured?

[Assistant]
The Fire Nation Man (can't believe that's what he's called) is most certainly staged.

The rest are probably actual fighting with a heavy emphasis on style over substance.

No one in those shows are going to get smashed into thin paste, that would be horrible. But *almost* getting smashed is something the audience will eat up.


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

[User]
[Harry Potter] Why did Snape's Avada Kedavra kill Dumbledore?

I've recently read on here that spells like Avada Kedavra on really work if you use with with passion and commitment. I just watched the 20th Anniversary and saw the Dumbledore's death scene and understandingly Snape killed Dumbledore reluctantly.

[Assistant]
He was committed. He had promised Dumbledore that he would kill him, both to spare him the painful death by curse that awaited him, and to spare Draco from having to do it.

You don't have to *enjoy* it - you just have to *want* it. At least, with the killing curse. Other spells can and do have more emotional requirements.


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

[User]
[Warhammer 40k] Why does the Imperium hold back?

in the grim darkness of the far future, there is only war. Humanity teeters on the brink of destruction. Technology has stagnated because... heresy.

So then why doesn't the Imperium allocate more resources to the "non heretical" technologies it has? For example... the Adeptus Custodes are supposedly as far above a Grey Knight as a Grey Knight is above a Space Marine. Why not just make 10 million Custodes? It's not like they're short on faux velvet ponytails.

Even if it took the resources of an entire planet to create one custodes (it really doesn't), shouldn't they get started? How many Tyranids do they think there are?

[Assistant]
"Forget the power of technology and science, for so much has been forgotten never to be re-learned".

 The only people who know how to make Adeptus Custodes are the Custodes themselves, and they aren't sharing. The Blood Ravens Motto of "Knowledge is power, guard it well" pretty much stands throughout the Imperium. The Mechanicus isn't sharing secrets with anyone either, which is why some planets might be able to still produce Leman Russ Executioners, while another forge world 1 sector away can barely produce the regular tanks.

This is probably partially by design though, to prevent another conflict on the scale of the Horus Heresy.


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

[User]
ELI5: Why is it sometimes cheaper to fly to a city by buying a ticket to another city which uses that first city as a layover?

An example would be: I want to go to Denver.  I can fly to Denver for $800, or I can fly to Denver, then boulder for $700.  Only I never go to Boulder and I just ditch the airport at Denver.  Why would airlines charge me less to send an extra flight?

[Assistant] It used to be that airfare was just based on distance. They scrapped that a number of years back, and overall prices have come down, but the new algorithms are pretty complicated. They base prices on number of competitors going there, time to departure, seat inventories, demand expectations, whether it is a hub, weekend, weekday, time of the day, and other things. As a result, you sometime get the situation where it's cheaper the way you describe. on the downside, you can only get one way tickets that way and can't check baggage.


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

[User]
Why have most animals evolved with four legs instead of three or five?

A tripod has three legs because that's the minimum number for stability.  It seems like biology would have also realized this, and that we'd see animals with three legs.  But that seems rare -- I can't think of any offhand.

So the argument might go:  Four legs were evolved because an animal with only three legs would be screwed if it breaks one.  But in that case, why not five legs?  Then there'd be extra redundancy.

Is there any consensus about the "why?" behind this part of evolution?

[Assistant]
One note: most animals with legs don't have four of them; six is by far more common, as it is the number of legs on insects.  And insects outnumber tetrapod vertebrates in both number of species and number of individuals by a longshot.  Other even numbers of limbs are common on other arthropods, but four is basically unique to tetrapods.

The reason limbs tend to come in even pairs is because most modern animal groups have bilateral symmetry, which means their left and right sides are more-or-less identical.  You do see odd numbers of limb-analogs radially symmetric organisms like starfish.


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

[User]
How are programs loaded into RAM memory?

I'm learning C++ and was reading about memory allocation. I'm trying to understand more about how memory actually works so I was wondering how programs actually interact with memory. I'm assuming the entire program wouldn't be loaded into memory at runtime so how does memory load and unload, for lack of a better word, the program?

[Assistant] The program is *memory mapped* into memory. This means that operating system reserves 5 MB (or whatever) of space for the program, but divides it into *pages* (chunks) of 1 MB (or whatever) and loads each page only at the first time it is used. The idea is that if you don't use a program feature it is never loaded.


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

[User]
ELI5: How did people figure out what was and what was not an element?

In the 21st century we know about atoms, neutrons, quarks and all that and we can describe what an element is through them. How did we make lists of elements before we knew about those?

[Assistant]
for most of history there was a lot of guesswork to it. in fact, if you look back at the historical names of some elements, you can see they would sometimes mistake a compound of 1 thing for an element of another. a lot of the highly reactive elements went unrecognized for a long time.

some of the biggest contributors to chemistry are the mol, ideal gas law, and colloidal properties. to state simply, these things care about the number of molecules involved. once you know how many molecules you're dealing with, you can figure out a lot of properties of those molecules. by comparing them with known elements, you can get a good idea of whether or not you have an element yourself.


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

[User]
ELI5: Why do people with cancer seem to get one last burst of energy in the week or so before they die?

I have had four people that I have known die of cancer.  One died within weeks of being diagnosed with stomach cancer.  The other three however went through the torturous multi-year process of fighting the disease.  In each case, there were times when the person looked literally near death - frail, tired, unresponsive.  Just not themselves.  Then in each case a few weeks before they finally died they suddenly perked up.  Not a little.  A lot.  They got color, energy, and seem excited about the future.  If you didn't know it you would bet these were healthy happy people planning to live a long prosperous life.  And then, the downfall comes fast and furious and in a matter of days they are gone.

Why does this happen medically?

[Assistant] Probably because the treatments can physically take you down harder than the disease itself. Yes the cancer is fatal, but without chemo and a host of other drugs, your body kinda recovers and feels significantly better than the treatments leading up to that point.


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

[User]
CMV: Lining up to get on an airplane is pointless.

This boggles my mind.

I know that some airlines are different like Southwest because they do not have assigned seats. But why don't people relax until their seating zone/group is called when you have a reserved seat?

It's not like the gate person knows that the boarding tunnel is clear or that the previous zone has almost completed been seated.

It just seems more relaxing for everyone to go in a "just in time" fashion versus standing in the tunnel, then standing in the plane and trying not to make the person in front of you who is trying to get into their seat anxious.

It's a small thing, but its madness and because we can only fit one lane of people in at a time it seems really inefficient for so many people to be standing around.

Edit: I absolutely don't mean that I would only get up the moment I gave a completely clear line to my seat. That's ridiculous and I'm not coming from a point of laziness. It just seems there's a lot more efficient things the airlines can do to make the process faster.

Edit 2: (Some reason Now for Reddit didn't succeed in saving this edit) I see that a lot of people have a great need for overhead space that I definitely underestimated. I'm not sure if I'm allowed to give everyone who mentioned this before my edit a  but I sure did try.

Edit 3: I also apologize to all for not being prompt in responding. Not surprisingly, I posted this just before getting on a plane.

[Assistant] On crowded flights, the overhead bins frequently fill up.  If you're near the last on the plane, you may be forced to gate check your bag, meaning you have to wait around at the baggage carousel when you get to your destination, plus no access to your bag during the flight.


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

[User] [Harry Potter] Why is Peeves afraid of the Bloody Baron?

[Assistant]
[](/discordchill) Peeves is a poltergeist, a spirit that derives its existence from the minor disharmony that's been generated among hormonal teenagers for the thousand years of Hogwarts' history. He isn't just mischievous; he's an avatar of the discordant.

The Bloody Baron had a level of discord and strife in his life and times that can overwhelm even Peeves. Just being in his vicinity makes the little poltergeist uncomfortable--while he drinks disharmony like water, the Bloody Baron is enough to make him feel like he's drowning. The Bloody Baron is an entity of hate and bitterness and rage that makes Voldemort look like a purring kitten. He's haunted the halls of Hogwarts for nearly a thousand years seething with a potent mixture of rage and regret, more than enough to make him the most inherently discordant being in the school.


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

[User] ELI5: Why is physically exerting yourself to the point of exhaustion at the gym good for you but various jobs involving manual labor seem to cause permanent damage in the long term?

[Assistant] Exercise is a controlled form of stress on the musculoskeletal and cardiovascular systems when done correctly. This, plus appropriate recovery time and nutrition, allows the body to strengthen itself over time via natural repair/adaptation mechanisms. Manual labor is not necessarily so controlled, and demands on the body may exceed its ability to adapt when repeated without appropriate recovery time -- which is not atypical for many of these jobs. Add workplace injuries into the mix and you can do quite a bit of damage over a career, whereas a reasonable exercise regimen under controlled circumstances should have a net positive result for strength, endurance, etc.


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

[User]
[The Purge/Home Alone] In all the confusion leading up to The Purge, Kevin's family leaves him behind. How does he fair?

Do Harry and Marv come to seek vengeance? Does Kevin turn to bloodshed?

[Assistant]
His parents thought they left him, he knew they'd be panicking. Their precious boy left behind on purge day of all days.

But Kevin hadn't been left behind. Kevin STAYED behind. His tween mind filled with violent fantasies, stories from purges past and just the general twisted nature of the youthful mind, had been bouncing around in his skull for ages now. Months of cutting the grass, of cleaning the kitchen, washing windows, it was all finally worth it.

Every year since he was born, his home had been broken into for the purge. Finally, his parents wrote off the house during that special time of year. Opting instead to take the family to a off-shore resort that offered purge protection.

Kevin's parents paid quite the premium to have insurance coverage during the purge (although as it only covered property damage it wasn't terribly priced) but that never made up for the emotional toil. Every year he returned to a ruined room, broken possessions, and the mocking laughter of his classmates. The McCallister family was a laughing stock. The McCowardly family, they were dubbed. But not this year, Kevin thought, no this year would be different indeed.

The alarms sounded, a voice announced the commencement of the purge. For a brief second, there was silence. Then the laughter started, the primal roars, the music. The Purge had begun, and anyone who entered this house did not know what they were in for.

The front door cracked open, and Kevin smiled.


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

[User]
What determines life expectancy in a lifeform?

Yesterday I visited my neighbor and he introduced me to his parrot. a smart grey fella with a red chest. my neighbor then told me he was 77 years old. I thought it was freaky that this bird has lived this long and I started googling average life expectancies of animals, and they seem ... completely random?! So I wanted to ask, is there any science behind why some animals live longer and some don't and could you explain?

[Assistant]
In mammals it's somewhat proportional to the resting heartbeat and metabolic rate. Even though they can be vastly different sizes, they all get about a billion heartbeats. Live fast, die young in action. Humans do a bit better, about 4 billion.

Different families of creature don't necessarily fit.


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

[User]
What happens if you reflect more sunlight on to a solar cell with mirrors?

Will it generate more electricity or are they pretty much maxed out in their regular set up?

[Assistant]
The solar panels' power increases more-or-less linearly with the amount of light falling onto them. Using concentrators (lenses or mirrors) is a good strategy for increasing power output cheaply. There are a few hitches though:

Temperature: Solar cells' efficiency drops as they heat up. More light on the same area of solar cells causes them to run hotter, and be less efficient. The diminishing returns effect isn't too bad, it is quite possible to go up to 1000 times amplification without too much ill effect. (I am not responsible for accidental eye damage and death rays if you try this at home).

Aim: Concentrators only work if the system is properly aimed toward the source of light. A little skew and you get nothing. Same goes for diffuse lighting: a little haze reduces their power dramatically. Regular cells power only drops off as a cosine of mis-aim, and still produce significant electricity on cloudy days.


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

[User]
[Star Wars] Why did the senate not question how Palpatine survived the Jedi assassination attempt

In revenge of the sith Palpatine has recordings of the conversation between him and the Jedi in his office. The voice of Mace Windu can be heard alongside several lightsabers being activated.

Why did no one question how Palpatine survived an attack by a jedi master? Did they know he thought them with a lightsaber? and if so did any derive, or care that he was a sith lord?

[Assistant] It's likely that he would've told them that Anakin Skywalker intervened and defended him. It's pretty well known, especially amongst politicians and the military that Skywalker was exceptionally talented, and carried out many extraordinary feats that no normal man ever could during the course of the Clone Wars. It's not inconceivable for them to believe that he could take on multiple Jedi masters, including Mace Windu, and defeat them, especially considering that they lack the knowledge to understand the Force and the ways of Jedi combat properly to see that it wasn't Anakin.


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

[User] ELI5: What exactly happens when a television commercial abruptly cuts out in the middle of its air time and another commercial plays after?

[Assistant] Some people buy ads from the national channel, some buy it from the local channel. If you notice, the vast, vast majority of ads that have this issue are shitty, locally produced ads that cut in over ads for big, national companies. So, basically, the local channel is selling ads over the space that national distributors may have sold - but explicitly sold with the knowledge that these ads may be oversold in local markets.


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

[User] ELI5: What is aftertaste and why is it so different than the taste while the food or drink is in the mouth?

[Assistant] Aftertaste is literally the taste of the food components after the food or drink is gone. Even after you've swallowed, flavor molecules will remain dissolved in your saliva or stuck to your tongue or inside of your mouth. When you swallow, only the flavors good at persisting will hang around, giving you an aftertaste that is different from the flavor of the food. For example, some common bitter tasting compounds can get inside the flavor detecting tongue cells and activate bitter taste sensations from there. Because they get inside taste cells they remain after you've swallowed and give a bitter aftertaste.


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

[User]
[MCU] In the Incredible Hulk (2008) General Ross wants to capture Banner so that he can turn his power into a weapon. So we know he REALLY wants superhuman soldiers. But he already has the tech to make supersoldiers. So, why doesn't he make an entire army of captain americas?

General Ross turns Blonsky into a supersoldier that is apparently on the same level as Captain America. And, since he spent years trying to capture the Hulk specifically because he was intrested in using him as a weapon, we know that he really, really, really wants enhanced soldiers. So, if he wants supersoldiers and has the tech to produce supersoldiers, why doesn't he make an entire army of supersoldiers?

[Assistant]
1. Hulk is considered by Ross as a Weapon of Mass Destruction, which he sees as more valuable than just a Super Soldier.

2. His pride is screwing with him, not only did he end up turning someone he had 0 respect for into a WMD it's someone he actively hates.

3. He sees Banner as a failure on his part and while he would never admit that, he wants to erase Banner from the board for making him feel small.

I wouldn't be surprised at all if Ross was ignorant enough to think Banner was in control of Hulk, but the likelihood is he doesn't care.


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

[User] How does Cancer kill.

[Assistant]
This is a very complex question to tackle.

A lot of cancer's ability to kill depends on where it is. If it is in a very important organ, such as the pancreas, it tends to be more likely to kill, largely due to its ability to inhibit normal pancreatic function. Without the hormones and enzymes your pancreas secretes, a lot of body function shuts down, killing the individual. The ability of cancer to do this to a single organ comes from the consumption of necessary hormones, excessive growth crowding out the cells, and the angiogenesis many tumors induce, causing blood supply to flow more to the tumor, and less to the normally functioning cells. No blood, no oxygen, no food, no living cells. Cancers like melanoma, in the skin, tend not to be killers from their primary location, but only when it metastasizes to other sites, especially if that new home is a vital organ.

The size/stage of the cancer is also a huge factor. Large tumors can drain a lot of hormones, blood and subsequently nutrients from normal tissue, inhibiting their function. Additionally, more advanced stages tend to have more longevity related mutations, making them better at surviving within humans. Beyond the nutrient/blood/hormone drain, this makes them much harder to treat and remove, especially once they metastasize.

Another way cancer is able to kill actually comes from the way we treat most forms, with chemotherapy and/or radiation. This is a toxic compound, designed to kill cells that are dividing, also known as growing. This is a hallmark of cancer, uninhibited growth, but unfortunately other growing cells get caught in this crossfire. This is the cause for hair loss in many cancer patients. With enough time, these treatments can lead to other problems that may cause death in patients that have other problems, such as age (old or young) or disease.

TL;DR The ability of cancer to kill depends on location, size/stage, and the route of treatment.


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

[User] ELI5: Why is it necessary for refs to stand in the path of a javelin throw. Cant they just stand on the sidelines and jog over after it lands?

[Assistant]
The javelin doesn't always land point-first and stick in the ground. When it doesn't, it kind of slides along the ground, but the meet official needs to mark it where it first touched the ground. To complicate matters, if it lands flat they're supposed to measure from where the grip hits the ground. If it lands tail-first, they measure from the tail. All of that is difficult to do when you're far away.

disclaimer: This hasn't always been the rule and may not be at some levels/in some regions.


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

[User]
[40k] Just how good of a guy was the God Emperor?

On the one hand, he did want humanity to rise and be powerful. On the other, he seemed to go about it in a fairly dickish way. So how good of a guy is he?

[Assistant] Getting a bit out of Watson here, but the God Emperor was a "good guy" in the same sense that Leto II, the God Emperor of Dune was a "good guy".  He was very Ozymandias-like.  He is responsible for the deaths of trillions of humans alone, let alone xenos.  Out of all that carnage, he insured galactic human survival and improvement.  He was a monster by any personal view, but a saint when looked at from a global, God-like omniscience.


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

[User]
ELI5: Why we can't, say, have 1000's
of NPCs fighting at the same time in
Skyrim, but we can have, say, 1000's
of zombies in L4D2?

L4D2 = Left 4 Dead 2 for those who don't know the game.

I've been wondering this. I mean, they both have to deal with pathfinding, animating actions, choosing who to attack, etc. So how come I can face a horde of 1000 zombies in L4D2, but having a 1000 NPC war in skyrim is not quite feasible for PC's yet?

[Assistant]
It's not about the capability. They're very different games and very different designs. L4D is built around fighting a "horde" of dumb unarmed enemies Skyrim is not and so was not built with this type of combat in mind.

On a much broader level the zombies in L4D are very very simple and just follow paths to run on then have a single simple attack. A game that involves massive amounts of enemies that might fire guns, bows, use magic, swords, etc. are much more complicated and it wouldn't be fun to have 1000 enemies with projectile magic or even just swords attack you all at once.

Short version: It's a design limitation not technology.


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

[User] ELI5: every now and then I will sleep for 18-20 hours in a row because of weird work shifts. For a few hours after I wake up my body feels like everything is on backwards. Motor skills are harder to use, walking is a challenge because my legs feel like they don't work. What is happening here?

[Assistant] Its called **sleep inertia** and is really common for people who catch up on sleep by resting for a really long period. On nights you expect to sleep this long drink a bunch of water and make sure natural light can get into the room (this will ease waking up for you). Try taking a cold shower and/or having a coffee 30 mins after you wake up.


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

[User]
CMV: Charity in its truest form does not bare your name.

I feel that if you are helping anyone out with 100% sincerity, it will not matter to you if people know that you are behind the charity, no matter how big or small the contribution.  I see large charities bearing the name of the person behind it followed by words such as "foundation" and I often see people on social media looking for a pat on the back for something good they've done.  This is still giving but the giver is still looking for something in return.

For instance, we have the Oprah Winfrey Foundation and the Trump Foundation, then we have Mathew McConaughey's charity 'Just Keep Livin" and Morgan Freeman's 'Rock River Foundation'.  Until I looked it up, I had no idea about the people behind the last two... and maybe they prefer it that way.

The stories in the news of anonymous givers have always intrigued me and make me have hope for mankind... like the recent one about the man at Walmart who paid off everyone's layaway items.  This man insisted on remaining anonymous.  He gave for the pure sake of giving.

[Assistant] If you are a person who is already famous (such as Oprah Winfrey, Bill Clinton, or Bill and Melinda Gates) then having your name on a charitable foundation can help it seem more legitimate, which increases donations and make the charity more effective.


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

[User] [Game of Thrones]Why do people people say that Jon Snow has a claim to the Iron Throne even after Robert Baratheon usurped it?

[Assistant] Robert Barathian has a claim to the throne through a grandparent (I think) of his being married a Targaryen. This gives him royal blood more recently than any other house. Should the line of succession fail (for example if he killed them all) then his family would stand to inherit the throne. It turns out that Jon Snow is actually Aegon Targaryen the legitimate son of Rhegar Targaryen the prince heir to the iron throne. This makes his claim to the throne much stronger than Roberts since he's actually the first in line. Of course what most people forget is that to be a king requires a kingdom. No point being the king of nothing, the people have to rally behind you otherwise you get a revolution.


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

[User] How big can black hole get ? Is there a limit ?

[Assistant]
If by "big" you mean spatial extension, there is really no way to answer this question.

The black hole itself is a singularity, meaning it has no volume whatsoever. Thus, the size of black holes is mostly measured by the radius of its event horizon (or *Schwarzschild radius*).

The size of the Schwarzschild radius is proportional to the mass of the black hole. Since the mass of a black hole has no upper limit, the "size" of a black hole could, theoretically, be arbitrarily large.


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

[User] [Dr.Who/X-Men] What would happen if Rogue touched the Doctor?

[Assistant]
Rogue's ability is limited to absorbing powers from humans and a small set of aliens. It would seem that most likely this type of human mutant ability would not have the ability to affect a Time Lord. Even if some of her powers did work, the result may not be desirable for her as Rogue is known to be able to absorb memories. We know that the human brain cannot contain Time Lord knowledge for very long without the brain destroying itself.

Also Time Lord regeneration isn't necessarily a power but something given to a Time Lord so even if she was capable of absorbing it, it is doubtful that she could could utilize it as a human.


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

[User] Energy can be converted into matter and vice-versa. Can energy be converted into antimatter?

[Assistant]
The terms "matter" and "antimatter" here are a bit misleading, because what we call "matter" in this context is just *ordinary* matter. Antimatter comprises the complementary antiparticles of ordinary matter, but antimatter is itself a form of matter. So converting energy into matter could mean converting it into antimatter just as easily as converting it into ordinary matter.

This is especially demonstrated in the process of pair production, where a high-energy photon (a gamma ray) interacts with a nucleus, spontaneously converting into a particle and its anti-particle counterpart, the classic example being an electron and a positron (the anti-electron). Typically these pairs will, due to their opposite electrical charges, pull each-other together once more and annihilate, forming a gamma ray once again.


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

[User]
Ice spontaneously appeared in my water?

I grabbed a 6 oz styrofoam cup from an inverted stack, so I know nothing was in the cup. I went to the water cooler. It's got a cold and regular spout. I put cold water into my cup. Looking at the water flow into the cup so I would know when to stop.  I put said cup to my lips and took a sip. It was really cold so I looked into the cup and there was what looked like crumpled up saran wrap so I freaked for a second. It was literally 80% ice in the cup in a huge flowing looking blob. How the f--- did that happen? I went back to the water cooler but could not make it happen again.

[Assistant]
You just discovered the concept of super cooling a liquid.  You can take a liquid below the temperature they would normally freeze at if there are no rough surfaces inside the vessel they're held in.  If there's no nucleation sites inside the water cooler, when it comes out the water will solidify on contact to a bumpy surface.

It's also the same reason you need to microwave a liquid with a plastic spoon or whatnot in the liquid.  If there are no nucleation sites in a vessel when you heat it, the liquid can suddenly burst into a full boil when you go to retrieve it.


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

[User]
ELI5: What is the social structure in Saudi Arabia like and why are there so many Saudi Princes?

The Saudi prince must be a bad man. From speeding in his lambo in LA, to causing stampede in Hajj, to sexually assaulting women in Beverley Hills. Who is this Saudi Prince?

[Assistant]
The Saudi royal family is very large. There are many Saudi princes that hold the top positions in the Saudi government. Basically, the religious establishment in Saudi Arabia provides legitimacy to the government of the Saudi royal family and, in exchange, the royals are ultra-puritanical in their rule.

The Saudi's basically provide a stipend to their citizens from the oil revenues of the state to prop up stability and Saudi Arabia doesn't have much of a real economy beyond the petroleum sector.


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

[User]
I don't understand "moles" as in chemistry or physics(?) at all. Is it just an arbitrary number?

Thank you everyone for all the responses!!!

[Assistant] Yes, Avogadro's number (approx 6.02 x 10^23) is just a number. You can think of it like a dozen - you can have one molecule, two molecules, a dozen molecules, or a mole of molecules. The number was defined so that the mass of the molecule in amu (atomic mass units) is equal to the mass of a mole of those molecules in grams. So in that sense it isn't arbitrary; it's connected to the mass of the carbon atom because that's how amu are defined. But the decision to define a mole as 6.02 x 10^23 molecules was just to make math easier and not for any deep reason.


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

[User] [Avengers: Infinity War] When Gamora realized what Thanos was after, and that she would be the key to his plan coming to fruition, why didn't she just slip through the airlock of the Benetar? That would have protected her secret much better than asking Peter to kill her with Thanos there.

[Assistant] Not everyone is psychologically capable of killing themselves. Gamora only attempted to take her own life at the very last possible moment. It's possible she spent the entire time working up the nerve.


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

[User] ELI5: Why do planets like Pluto (and non-planets like the moon) have a seemingly large number of craters in them compared to Earth? Wouldn't a small planet like Pluto be missed by the vast majority of asteroids?

[Assistant] Earth has an atmosphere that burns up asteroids on entry, and weather that washes and erodes the craters away over time. Smaller planets still are going to get hit by asteroids eventually, over millions of years the odds of being struck, even for a small planetoid, is still inevitable. It's just that without an atmosphere, it's easier to see all of the older craters.


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

[User]
Maybe silly question, but what are ceps? We have biceps, triceps, and quadriceps, but I've never seen what a 'cep' was. What's different?

I like semantics a lot, and in submitting papers I've found it's really important to be very specific so people can know what you're talking about just from your paper title. But it just seems some terminology comes out of nowhere and doesn't really add to the description. What I find weird is that in this case, muscle size/strength is almost directly correlated to the number of 'ceps'. Just sayin...

[Assistant] "ceps" is Latin for "headed". Muscles that end in "ceps" generally are made of a number of bundles which attach to bone, with the prefix denoting the number of attachments (which may or may not be from the same bundle). It stands to reason that more bundles is correlated with increased strength, but it's not always true.


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

[User] What triggers beta particles to form, and for what reason can they not penetrate substantially thick aluminium?

[Assistant]
Beta particles are created when a nucleus undergoes beta decay. The weak force allows nuclei with unfavorable N/Z ratios to exchange protons for neutrons (and vice versa) in order to reach a more stable species along the same isobar.

Beta decay Q-values tend to be on the order of 1 MeV, and the emitted beta particle can have any kinetic energy from 0 up to the Q-value. An electron or positron with 1 MeV of kinetic energy doesnt penetrate very far into dense metals (and even less so for lower-energy betas). Beta particles primarily interact with matter by scattering off of atomic electrons. Metals like aluminum have a high atomic number (Z), so any electromagnetic process will be enhanced compared to something to with a lower Z.


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

[User]
ELI5  Why are the United States' coins and Canada's coins basically the same size, shape, and color?  What happened that the two countries decided this would be a good idea?

I have Googled this and can't find a reason.  I would love to know.  Help!

[Assistant]
This is pure conjecture, but perhaps it is a relic of past times when the value of a coin was tied to the value of the metal used to make it.

Gold is the most valuable, so you could have a $5, $10, $20, etc coin, with the value determined by how much gold is in it.

Silver is less valuable, and in the US, quarters were silver until 1965.

For the smaller denominations, nickel or copper are used, these being metals of even lesser value.

I would imagine a couple hundred years ago when the US and Canada started making their coins, the amount and type of metal used to make a coin of a certain value would have been similar, so the size, shape and color of each coin is the same.

Now that it's all fiat money anyway, all the coins are made with less valuable materials, but the basic design of each coin has remained the same.


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

[User] Why are surgical masks blue? Why are they never a different color like red or purple?

[Assistant]
This is mostly so they match the rest of the scrubs that medical professionals wear which are typically blue or grey.

I believe the original choice was so that it was the opposite of the colour red (on a colour wheel) and would, therefore, be "refreshing" on the eyes in comparison to looking at wounds.


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

[User]
Is there any good side to doing the same thing over and over?

Some thinkers have criticized jobs where one does the same thing over and over, such as working on an assembly line. Thinkers say this is stifling to the human spirit. I was just wondering if there are good sides to doing the same thing over and over. I suppose if one worked on an assembly line working on the same part over and over might force one to think more about the appearance/aesthetic appeal of the part than if one didn't make that part, its composition, its use, or other aspects. Perhaps this contemplating the part more than one would otherwise would be fulfilling in some way.

[Assistant] Sisyphus was condemned to repeat the same task over and over. Albert Camus asked in The Myth of Sisyphus that life itself is futile, why bother? Life itself is repetition  wake up, survive, sleep. And most jobs are monotonous, anyways. The answer was acceptance of the futility of life to reach some sort of peace. Thats a crude summary of a great essay.


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

[User] ELI5: Why did early pistol and musket designs have such unergonomic looking grips?

[Assistant]
Ergonomics as a science hadn't been invented yet, and guns were mostly handcrafted pieces, so each gunsmith was kind of just doing his own thing.

Ergonomics also isn't all that important when you have a gun with no sights and you're only expected to fire a couple rounds a minute at most.


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

[User] Why don't we take blood from dead people?

[Assistant]
Blood taken from dead people is actually very usable.  The first experiments were done by taking blood from a dead dog and putting that blood into a living one -- if it were done within ~6 hours, the living dog suffered no ill effects.

Taking blood from cadavers was done in the Soviet Union, but it didn't catch on in America because of the general public's feelings toward it.  It also raises the question of consent -- would a patient be okay with blood from a dead person?  Would the deceased's family consent?

It's just a sticky situation with current mentalities -- similar to the issues that plague cadaver research.

Source:  This was all taken from the book *Stiff* by Mary Roach.  It's a generally well-regarded nonfiction.


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

[User]
Breaking into the Publication Bubble

It seems as though there is an awkward, unspoken line between Master's and PhD students that publish or do not publish. I am finishing my Master's in a program that does not encourage students to do much research or consider publication. However, I am starting a PhD program in the Fall where I know several of the students have multiple publications.

When I ask people about publishing, it either seems second nature to them and they forget important details (i.e. my boss) or some students want to keep a competitive advantage and don't want to sit down and explain how to go about doing it.

Any resources you all could recommend on how to do this? I know several other students that would appreciate this as well.

[Assistant]
Read the submission guidelines for a few major journals in your field. What do they have in common? What idiosyncracies do individual journals have?

Tighten up your potential submission as much as you can for the journal you want to send it to, but recognize that--**no matter what**--editors & reviewers are going to have critical feedback intended to help strengthen it further. This is a good thing.

Come to terms with the fact that sometimes this feedback is phrased in a way that stings. It's ok to be frustrated/pissed off at this. We've all gotten it. Part of the process is moving past it and figuring out how to use that feedback productively.


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

[User] [DC Comics] With the rest of the heroes out of commission, could the Batman and the rest of the Batfamily defeat Doomsday?

[Assistant]
Probably not, on their own.

What Batman could do, however, is manipulate metahuman super villains into fighting. While Batman might think against attempting to pull someone like Anti-Monitor or Darkseid to Earth, someone like Mr. Mxyzptlk has a high level of both power and gullibility could be used essentially as a weapon. As powerful as Doomsday is, Mxyzptlk could turn him into a plush toy if it pleased him.


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

[User] ELI5: Why does riding a roller coaster feel so much faster than driving in a car at a similar speed?

[Assistant]
Roller coasters are designed with much steeper hills and tighter curves than a road. This causes it to feel more "jerky" and out of control even at more moderate speeds.

That said, some coasters do in fact reach or exceed vehicle speeds. The record is approximately 150 MPH. There are at least 5 coasters that launch forward reaching over 100 MPH in under 5 seconds.


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

[User]
Can governments bypass encryption ?

If encryption algorithms like AES and RSA are technically impossible to crack with our current technology. How do intelligence services or governments intercept communications?

[Assistant]
> technically impossible

They are not 'impossible' to crack... just economically or time in-feasible

Other ways to intercept communications are before or after the encryption/decryption (i.e. malware on your computer, or in the email/website/whatever hosting server/network). Preventing the encryption in the first place (i.e. man-in-the-middle attack, forged certificates etc.). Social Engineering (convincing you or an employee of the third-party company to leak either the unencrypted data, or a secret/admin-rights to allow decryption).


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

[User] My grandma takes nitroglycerin pills for her heart. I was led to believe that nitroglycerin is incredibly explosive. Why hasn't this been an issue for her?

[Assistant]
Nitroglycerin in tablet form is stabilized inside of a water-soluble polymer called povidone.  It is also fairly disperse in that one pill contains less than a milligram of nitroglycerin, meaning you wouldn't be able to get it to explode if you wanted to.

The largest problem is that the active ingredient decomposes over time, which is somewhat prevented by the povidone, but it won't last forever.


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

[User] [The Culture] They've been around god knows how long, why don't those Culture freaks just sublime like everyone else and let someone new sit atop the galaxy?

[Assistant]
The Culture is a collection of several space faring civilizations that joined together about 9 thousand years ago.  In the context of the universe, that is a vanishingly short time to be "involved".

Parts of the Culture do break away and sublime on their own, but the Culture "proper" feels no need to "vanish up their own behind", as it were.  The Culture isn't finished doing good works and generally making the universe a better place.

Also, any civilization can still become a major player on the galactic scale.  In the past few thousand years there have been anywhere from 7 to 11 civilizations included as part of the 'Optimea'.  So its not like the Culture is alone at the top.


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

[User]
[DC] What is Darkseid's age?

Like, how old IS he exactly?

[Assistant]
Darkseid IS.

We know he's younger than the multiverse, but that's it. The Fourth World (Apokalips and New Genesis) is 4.8 billion years old, so at the oldest he's 4.8 billion years old. Is he older? Possibly, we don't know how long that Uxas (the name he had before he became Darkseid) was around.


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

[User]
[Science Fiction General] What's the first example of science fiction addressing the concept of immortality?

Hi all, I've been thinking about this in relation to religious and spiritual texts that address immortality and was wondering about this in sciencefiction!

From what i've been able find is Gullivers Travels, but from what I remember of the story it doesn't *really* fit in as sciencefiction.

[Assistant] I would assume the *Epic of Gilgamesh.* It's not science fiction--it's an epic--although given the subject material, it could retroactively be considered science fiction in some aspects. The *Epic of Gilgamesh* details the adventures of Gilgamesh as he travels the world in search of immortality.


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

[User] ELI5: How do apps or websites that have offerwalls know that you installed and ran an app on your device or completed the offer?

[Assistant]
Theres usually account information associated, either with you or the app.

When apps run, they can register details on your computer or device, and, of course, call home.

Some token or tag will be shared. Its really that simple.


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

[User] [ELI5] If sound is matter vibrating, and the speed it vibrates is pitch, what dictates volume? Is it the amount of matter vibrating, and if so, does that mean theres a max volume for air?

[Assistant] The energy it carries, which is apparent by the amount of space by which it displaces particles, known as amplitude. Im not aware if there exists a max volume, but theres definitely a threshold where it begins to cause damage to things.


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

[User]
ELI5: Why were castles/fortresses effective?

Couldn't an enemy army just march around the castle and take all of the unfortified farmland/resources? Also couldn't a castle just be sieged out until the defenders starve?

[Assistant]
> couldn't a castle just be sieged out until the defenders starve?

Of course, that's what happened all the time. However you can have a *lot* of supplies within the castle walls and so if the invader couldn't capture the castle quickly enough they'd run out of time and resources. You'd optimally not campaign in the winter if you could avoid it, and you're not going to be able to use the enemy farmland since you're likely not going to stay in that spot for long enough. The defending population would if they are smart already have harvested whatever they could and get it in to the castle.

Castles also could store a lot of troops, which meant that if you marched around the castle and tried to keep the campaign going suddenly you had an enemy in your back that could cut off the supply line, flank you, or work together with a different army to surround you.

Additionally castles could be used to delay the enemy while you wait for backup. If you know that there is a larger army coming but they will take two weeks to get here having a big wall to defend yourself for those two weeks until the backup could come and help you fend off the invaders was a much better strategy than not having the wall.


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

[User]
ELI5: Banks/Building societies won't provide mortgage on a flat in a building with more than 6 floors in the UK, what is this arbitrary restriction and why does it exist?

As title says, what up with that?

Edit: thanks for responses. The building society put the policy into effect last year, they wouldn't give me a specific reason but believe as some others have said that they don't think it's a sound investment due to number of flats. You can pay for a valuation but it's 450 quid and has no guarantees were going to go with another mortgage lender.

[Assistant] There are 2 types of "owned" property in the UK.  Freehold and leasehold.  In a Freehold property you own the land beneath your house.  In a leasehold you only own the actual house.  Now most leases last for hundreds of years, passing through generations of family who pass ownership of the lease onto a family member.  Eventually the lease will run out meaning the person who owns the building has to buy out the lease or surrender the property.  All high rise buildings are lease holds.  Because there is a chance you will lose ownership of your house banks will not offer mortgages on houses with soon to expire leases.  As most high rises were built in the 1960s on 100 year leases it means the risk is far too high for the bank (who would also have to surrender the property to the leaseholder).  It is irrelevant which floor you are on.


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

[User]
[spoilers] [Terminator dark fate] what was the plan?

Grace was sent back to save Dani. But she was barely effective against the rev9. Earlier defenders at least had a plan and a way of damaging terminators. But Grace didnt seem to have a plan other then running. And she wasnt great at that either with all the security footage .
There mustve been a better plan before she was send back?

From the other side, why did legion send only one rev9? We know it had legions. The fight seems to be in full swing. Grace doesnt have stories about the rev9 being a last ditch attempt like the original t800 was.
Two of those things wouldve ended things pretty quickly.

[Assistant]
Both times a human has been sent back, the plan has been to run. Kyle Reese said quite plainly that he wasn't sure he could destroy a single Terminator with the weapons available in 1984. He never planned to confront it; he was always going to run.

If Grace had been able to bring weapons with her, she very likely would have been a match or the Rev9. Her metabolism is tuned for quick combat, and she said that "you either kill a Rev9 in a few seconds, or you die," or something to that effect. It's apparent that the augments have at least some success taking our the newer Terminators.

As for her plan: Grace grew up in a post-technology world, so she didn't know a lot of the things that would be necessary to evade the Rev9. She doesn't really understand security cameras, cell phone signals, or the ever-present surveillance state. She basically got lucky in meeting Sarah Connor, who had both experience in evading Terminators and evading modern law enforcement.

There's a lot we don't know about time travel, especially since everything after *T2* is no longer canon, but it seems like time travel is very difficult and very expensive. This is the only explanation for why both Skynet and Legion only send one Terminator at a time, because you're right, an invading force would be much more effective. It's also possible that, like Carl, Legion *did* send multiple Terminators, but sent them to various points in the time stream.

Time travel was, for Skynet, a last ditch effort to prevent failure. For Legion, it's probably more about optimization. Grace said the nuclear was was intended to stop Legion's "spread" across the globe; it's more akin to a virus than an all-powerful control mechanism. Legion searches out weak points, inserts itself, and grows stronger. It searches for enemies, and then searches for a way to neutralize them.

Even if she wasn't *winning* the war, Dani Ramos was the biggest threat to Legion. When it discovered time travel, it would have been natural for Legion to use that technology to continue its spread, and to find a way to neutralize its greatest threat.


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

[User]
[Avatar/Korra] Do earth benders and fire benders have spiritual powers?

We know that water benders have spiritual powers (healing/spirit calming) and air benders do too (astral projection). Do earth or fire benders have spiritual powers similar to those?

[Assistant]
I believe's Toph's ability to see the whole world through the vines at the swamp she now resides in is a spiritual power she learned through earthbending.

The Fire Sage who found Korra when she was amnesiac was also able to use healing through firebending.


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

[User] ELI5: How does diabetes cause damage to the point that your eyes go blind and they have to amputate your limbs?

[Assistant]
Accumulation of excess glucose in your blood eventually collects on the walls of your blood vessels in a process called glycosylation. This buildup of glucose leads to a series of changes in the blood vessel walls which causing the blood flow to certain organs to be blocked off.

Another place where glucose tends to accumulate is inside nerve cells. Eventually this buildup starts interfering with cell traffic and is toxic to these nerve cells. Diabetes results in many complications for the body, mainly through its effects on the blood vessels and nerves discussed above.

In the retina of your eye, this leads either your cells starving and dying off (retinopathy) or an abnormal response where the eye attempts to grow new blood vessels to supply itself. These new blood vessels are not very structurally sound and tend to leak, causing bleeds and the retinal cells to swell up thus impairing vision. High glucose also predisposes you to cataracts and other causes of blindness, but retinopathy is largely irreversible.

In your legs the nerves are often the first to be affected in chronic diabetes because they are the longest in your body. Because you start to lose sensation in your feet, your body does not automatically correct itself when it is putting too much pressure in a particular area e.g on your heels when walking or your toes in a tight fitting shoe. Compound this with the poor blood supply in diabetes, the skin gets damaged and heals poorly (an ulcer) and becomes easily infected. Your immune cells can't reach the wound site through the diabetic vessels to fight the infection so it spreads into your bone and up your leg. By this stage the best option is to amputate the leg before the bacteria reach the rest of your body.


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

[User]
[Avengers:Infinity War] Wouldn't it have been a better idea for Thanos to just reduce the physical size of all the beings to Ant-size?

That way no one dies, an apples feeds 200 people, and resources grow faster than they are being consumed. Win - win right?

[Assistant]
Theres a ton of things Thanos could have done differently to solve the problem of overpopulation and lack of resources.

But the point of Thanos is that hes insane and fixated on one omnicidal idea to achieve balance.


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

[User]
CMV: Deafness is, and should be, considered a disability.

Let me preface this by saying I do not have ANYTHING against deaf people, and that I don't think having a disability of any kind makes you any less of a person.

The word disability has multiple definitions, but the one I've come across that fits best here is: " a physical or mental condition that limits a person's movements, senses, or activities."

Deafness is a condition that not only limits a person's senses, in most cases it completely gets rid of a sense. I don't see how this can be anything but a disability. Deaf culture is a wonderful one, and I love reading about it, but if everyone in wheelchairs formed a culture of their own and started claiming they weren't disabled because of it, this would be met with extreme skepticism.

Again, I want to say having a disability does not make you any less of a person. I know many deaf people are proud of their deafness, and not only is that okay, it's wonderful! but that doesn't change the fact that deafness is a disability, as it completely removes one of the most important senses in the human body.

[Assistant]
> a physical or mental condition that limits a person's movements, senses, or activities

Should a person still be considered disabled if they find solutions that alleviate the consequences of these conditions? What if the impairment has no remaining significant effect on their current standard of living?


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

[User]
Would an object with twice the mass (and size) of the moon, situated twice the distance away from Earth that the moon is now, have the same effect on the tides as the moon?

Not sure if this is Astronomy or Planetary Sci. Ill change if it does not fit.

[Assistant]
First of all, gravity falls off with the square of the distance. So an object twice as far away would only exert one quarter of the gravitational force. So this hypothetical object would have to be four times the mass of the Moon.

But there's more to it. The tidal force is a consequence not of the total gravity from the Moon, but rather the difference in gravity at the side of the Earth closest to the Moon compared to the side that is furthest away.

With a lighter, closer Moon this difference is larger than with a heavier, more distant Moon. This is why the largest contribution to the tidal force on Earth is from our Moon and not from the Sun, even though the force of gravity of the Sun on Earth is greater than that of the Moon.

The exact dependence between distance and tidal force is complicated, but the falloff of the tidal force is closer to the cube of the distance. That means that a hypothetical heavy Moon at the twice the distance would have to be about 8 times as heavy as our current Moon to replicate our current tidal forces.


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

[User]
ELI5: Why is it so easy to take in 10k refugees and house them rather than house homeless veterans? (in America)

I know this question may sound political but when I recently saw this, I thought it was a no brainer (meaning to house veterans rather than refugess).

Therefore, I'm assuming theres more to the story than just the simplistic *refugee vs. homeless veteran* narrative.

[Assistant]
The state-funded resettlement agencies are going to assist them in finding housing and work for 90 days. If they have family, they'll be flown into the nearest resettlement center. After that, AFAIK, they receive no special treatment, but are free to get the same support from Health and Human Services that is already available to the homeless and others in need.

The fact that the US gov't gets to determine where they go might be a factor too. Homeless are not exactly proportionally spread out across the US, and cities/states can get a lot of flak for trying to move their homeless elsewhere, which wouldn't be an issue for the federal gov't. They can just drop refugees in smallish towns or less expensive cities that are prepared to take them.

Also a lot of long-term homeless, veterans or otherwise, are mentally ill. This may mean that they are unable/unwilling to ask for help, or that the shelters and such are unequipped to provide it.


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

[User] [star wars] how did Leia get into possession of R2D2 and C-3PO in A New Hope?

[Assistant] They were her fathers droids after revenge of sith. R2d2 was assigned to his diplomatic ship and 3p0 to his personal entourage as a translator. Some time before the events of rogue one they 3p0 and the tantive 4 were given to Leia for her sentate duties and rebel activities.


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

[User] [LEGION/MARVEL] How the Shadow King's powers work ? Does he need a body to use telepathy ? Can he use his power with a non-telepathic body ?

[Assistant]
The Shadow King was human, once. Once. He had a body, one he was born with, and his powers of telepathy and psychokinesis were second to none. With potent psychic power comes a link to the Astral Plane, a dimension where thought reigns supreme. Most sentient beings are linked to the Astral Plane in one form or another, it's the Unified Field of Psychic Consciousness. Most beings, however, only ever find themselves there when dreaming, or in a comatose state. Psychics, however, can go there at will, and have immense power there. It's a reality where they can control and manipulate anything they like.

The Shadow King was born a man, but with time and practice became incredibly adept at moving to and from the Astral Plane, until finally his identity became separate from his physical being. He became an entity of the Astral Plane, with all his abilities and powers linked to his new state of being instead of his old one.

So, no, he does not need a physical body to use his telepathy. Anyone he would use that ability on is linked in to the Astral Plane, which is now his home dimension. He needs physical bodies to experience the physical world. Without a meat suit, the best he can do is whisper in people's ears and make them see things that aren't there.


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

[User] ELI5: Why do smaller aircraft tend to have their engines on their fuselage while larger ones tend to have them on their wings?

[Assistant] Smaller aircraft often only need one engine and you want that engine in the center of your aircraft. Larger aircraft will often need two engines or more and so you can't put two engine in the center, that's just too big and wouldn't leave you enough place for the pilot. Usually in that case, they will put those engine either under the wing or behind the aircraft on both side (called Aft mounted- engine). Each solution have their pros and cons, but usually winged-mounted are preferred because the engine are close to the center of mass of the aircraft and they are easier to access for maintenance. One of the disadvantage is that you are limited in the size of your engine by the clearance under the wing.


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

[User]
ELI5: What is that feeling/taste you have after water runs up your nose?

For example, this morning while I was washing my hair in the sink I felt some water running up my nose and shortly after I had that weird feeling/taste in my nose.

[Assistant]
The linings of your nose, sinuses, trachea, bronchi, etc are basically epithelial cells, mixed in with some others.  These cell types on these organs prefer a slightly salty coating because [complicated evolutionary reasons here which aren't pertinent to your question and an explanation would be very long winded].

When fresh water hits them, it screws up their osmosis and they suck up water until they burst.  This causes the pain you feel...your cells dying because fresh instead of salty water hit them.

Conversely, if you need to clear out an object, insect, or what have you from deep within your nose, make a weak salt solution with luke warm water.  This will eliminate the pain you feel while trying to extract the object.  If you can't get such an object free on your FIRST try, go see an ENT. :)


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

[User]
What's the deal with viruses? Are they alive or not?

In high school they tell you viruses are not living things, but I know college professors that will tell you they technically are. Is there an official consensus?

[Assistant]
Depends on how you define alive.  Contains DNA? (Ding! that's easy.).  Contains proteins in a membrane? (Ding!).

Viruses replicate (but then again, so do prions).  They sometimes contain some of the parts to replicate themselves (see the Pol protein in retroviridae as an example) so they do have some of the machinery to reproduce.

One big difference is, viruses can't replicate without other machinery (most notably the ribosome and often some DNA or RNA synthesis machinery).  But, that isn't exactly a unique property of viruses.  Plenty of other organisms rely on outside "machinery" to help propagate and almost everything has some sort of outside dependency (humans for example need a whole series of gut flora and essential nutrients to survive).

So the big determining factor should be whether a virus generates its own energy in order to replicate.  Single-cell organisms (and all higher-order ones) generate energy by breaking down some nutrient molecule and uses that towards cellular processes.  A virus does not.  If this is how you define "alive" then viruses are not alive.

The really interesting question is: are self-replicating RNA sequences alive by this definition?


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

[User]
ELI5: When something burns down and turns into ashes, it takes up significantly less space... where does all the stuff go?

I don't know if I am phrasing this to be understandable, but when you burn down something the resulting ash has a significant smaller volume than the object you burned. Why? Where does all the matter go?

[Assistant]
The air.

The carbon and hydrogen in the fuel combine with oxygen to create CO2 and H2O (water). These just go up in the air (CO2 is gas in room temperature, water from fire is still hot so it's steam). Other particles float away on the hot air as smoke.