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

[User]
How do surgeons stop internal bleeding?

Movies/TV make it look like treating gun wounds is a matter of removing the bullet and stitching up the wound, even when bleeding heavily. I'm thinking there must be more to it than this, like stitching up insides or something.

[Assistant]
Lots of ways!

As Gestapoparrot, it depends a lot on the nature of the injury. There are lots of haemostatic techniques, which vary in complexity. Loosely, from simple to complicated:

1. Do nothing: Minor haemorrhage in a patient with unimpaired intrinsic haemostasis works surprisingly well for stuff like superficial ooze from solid organs.

2. Direct pressure. Direct pressure on a small bleed with a finger/gauze pad can do wonders. There are also dressings that help improve blood clotting (through the addition of things like calcium, which helps blood clot) which can be also packed in. I've also found soaking gauze with adrenaline (to help contract blood vessels) works, but not sure if it is more effective than gauze alone. If you have a big bleed, direct pressure with a finger or a clamp on the artery further upstream can give you time to mend the defect or prevent exsanguination while you resect the injury if it is not salvagable. Pressure is great.

3. Electrocautery: Diathermy uses heat (from electricity) to fry whatever you're pointing at. Unipolar diathermy has a big pad stuck to one part of the patient, you hold the other end which looks like a pen and electricity flows through from one end to the other. It has a switch on it which you can flick to fry offending bleeders and stray erythrocytes that irk you.

4. Ligation. You can tie a surgical tie around a vessel to stop it bleeding. If you can't see it exactly, you can tie a figure of 8 tie around the area where it is spurting from.

5. Packing. Packing, in simple terms, is stuffing the area full of gauze until bleeding stops. Technically it is a bit more difficult as there are lots of options; you can pack from within an organ, or from without (e.g. if you have a cut through a liver and you can approximate each side you can splint and compress it by packing around the liver).

6. Balloon tamponade. If you have a massive bleed in an appropriate cavity, you can stick a foley catheter or whatever else you have to hand in there and inflate it, putting lots of pressure on the bleeding area. Examples for post-partum haemorrhage (bleeding uterus after delivery) and oesophageal bleeds (where you can put down a device called a blakemore tube to basically compress the oesophagus from within).

7. Formal vascular repair. If you have a big injury to an important vessel, there are no other more pressing issues, and the patient can take it, you can try and formally repair the vessel with a graft or somesuch.

These are a few of the surgical techniques for haemorrhage control. Not all of them are useful in all situations, some take more time than others, some are better as a temporary solution while a definitive one is prepared.

Having a good anaesthetist who keeps the surgeon up to date with the state of the patient and keeps them alive while they are actively trying to die and filled with clotting factors/blood/platelets (so their blood can actually clot) is also essential.


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

[User]
[DC] Is Superman good because he's innately a good person or because the Kents raised him well?

If he were raised by a cruel parent would he grow up cruel? Would another Kryptonian raised by the Kents come out as good?

[Assistant]
It's always implied that the Kents formation and education shaped Clark's ethics and morale, and even his environment and background helped it too.

But... almost all the alternate versions of him not being raised by the Kents (raised by the nazis, by the soviets, by quakers, by the government, by british...) give him the same goodness, reinforcing that in fact it is innate.


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

[User] ELI5: 64bit and 32bit. What are the pros and cons of each? Why is tech moving towards 64bit?

[Assistant]
Really like you are 5?

64 bit can do math on bigger numbers, it can do math on smaller numbers(more precise), and it can memorize more things.

32 bit is cheaper and lower power that is it (for those of you that are going to argue that memory savings are another advantage, what does memory cost?)

High end cpus are moving towards 64 bit because going faster got a lot harder around 2003 so going wider was cheaper and almost as effective.


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

[User]
[LOTR] Why didn't Elrond force Isildur to throw the ring into the Cracks of Doom?

They finally defeated Sauron and are inside Mount Doom. When Isildur refused to throw the One Ring into the Cracks, why didn't Elrond kill or force him to destroy it? He would have saved another age of darkness and suffering.

EDIT: Referring to the movie. I do not know exactly what happened in the book.

[Assistant]
1. Isildur was a Numenorean of the Second Age, making him about as strong as Elrond himself. The fight between them couldve easily ended with Elrond dead and thrown off the cliff.

2. Elrond knew he wouldve been corrupted by the Ring if he wasnt careful.

3. Elrond and Isildur are kin and war buddies (for lack of a better term). The former simply couldnt bring himself to hurt the man he was once proud to call a brother.


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

[User]
Can T-lymphocytes of a person be cloned in vitro?

If so, how is it done?

Via bone marrow extraction perhaps?

[Assistant]
T cells can be isolated and cultured directly from peripheral blood.

Ficoll gradient centrifugation is used to separate peripheral blood mononuclear cells (PBMCs) from other blood components.

From there, cells of interest (i.e. t cells) can be isolated using antibodies against specific surface markers (e.g. CD3 for t cells) and magnetic beads (see any cell isolation kits from thermofisher/miltenyi for example protocols).

Bone marrow aspirate could also be used but peripheral blood is more convenient, depends what the purpose of the experiment is.


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

[User]
ELI5: Why is so much emphasis placed on the first 100 days of the U.S. Presidency...why not 60 or 120 or any other number?

I know that the beginning of a new administration is a good litmus test for how effective it will be, but why exactly 100 days? Is there something specific about what can happen during this timeframe, or is it mostly arbitrary?

[Assistant] It dates back to FDR's first 100 days in office. During his first 100, he created a madhouse of policy change, bill drafting, signing, and law shifts in the nation. It was considered so intense that it became common place to measure the first 100 days of newer presidents against it. While we no longer compare to FDR for the 100 day rule, it's generally believed that the first 100 can give us insight into what might be the new norm. If they can hold their promises, unify, or in some sad cases. Divide.


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

[User]
ELI5: What is happening when someone is "seeing stars?"

I just sneezed four times in a row and was seeing stars for a few seconds. What exactly happens to make you "see stars" and how bad is it?

[Assistant] This is caused by pressure on the back of your eye or optic nerve. Your brain interprets signals from the nerves associated with vision as light. So if you rub your eyes and put pressure on them you'll see light patterns even when you're eyes are closed. If you take a strong hit to the head you'll "see stars". When you sneezed you likely put pressure on your retina, which was turned into an electrical signal, which confused your brain into interpreting the input as strong flashes of light.


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

[User]
CMV: Protesting by blocking roads and the flow of traffic is not peaceful

Within the past decade the number of protest has increased, specifically those from the left that are blocking roads where everyday middle-class Americans are trying to go about their lives from the left and the right. When you are blocking traffic and preventing those from reaching their destination you are not protesting peacefully. Protesting peacefully would be standing on the *side* of the roads, speaking as loud as you want and holding signs to prove your point. Not only are you literally breaking the law when you're blocking traffic, you're probably hurting your cause. No matter what the cause is, if I see ANY group protesting by blocking my way home from work, they immediately just lost respect from me. I don't care what you are protesting, it could be PB&J sandwiches are bad for all I care, if you are blocking people from just simply living their lives, and at times jumping on their cars, you just lost my respect. And the point that "they don't listen to us if we stand on the side of the road" is not a good argument. Most people don't listen to a lot of things, that's the way it is. That doesn't give you the right to make my life any harder. I even recall the time a group protesting by standing in the road wouldn't even let an ambulance pass, which is just disgusting. I would *almost* go to the length to say if you are standing where people are *suppose* to drive, and you won't get out of their way, they *almost* have the right to hit you. Honestly, what do you expect to happen if someone had a long ass day at work, and is just trying to go home and see their family. You think they are going to be happy? You think they are going to support your cause? No. They will immediately despise you.

EDIT: I would like to point out the fact I included "jumping on cars" in my post. Maybe I should have highlighted it more, but it IS there. Ultimately I'm getting to the point that modern day protesters that are attempting to protest by blocking roads almost always is leading to jumping on cars or surrounding/intimidating drivers. I suppose I should have clarified further.

[Assistant] One of the quintessential examples of peaceful protest is the sit-in. And the sit-in's entire purpose is to disrupt people's daily routines. You sit in people's way just to make their normal life more difficult. If we then say that disruption to people's routine is not peaceful then what is the sit-in? Is it no longer peaceful, this the cornerstone of peaceful protest?


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

[User]
Why do galaxies appear as consistent objects, given their sheer scale?

Wouldn't the closer part of a galaxy hundreds of thousands of light years across appear more like it is now than the far side of it?

E.g. we'd be seeing the closer side as its rotated closer to now, but the further side as it rotated much longer ago, thus it shouldn't really look so consistent, like a pinwheel.

[Assistant]
Hundreds of thousands of years is actually quite a short period of time in astronomy. Even very short-lived stars last for millions of years.

The distance to other galaxies is also much larger than their size. Andromeda, the closest large galaxy to us, is millions of light-years away. We can say many other objects that are *billions* of light-years away. On that scale, we definitely notice that closer galaxies are more evolved than more distant galaxies. But on the scale of an individual galaxy, a hundred thousand years is almost too small to notice.


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

[User]
[Mario Universe] Are Boos the spiritual remnants of humans, or are they simply an intelligent species that resemble what we think of as 'ghosts?'

Are they actual, back-from-the-dead ghosts? Luigi's Mansion has both Boos and humanoid ghosts, which suggests they are two different things. However, King Boo is revealed to be (SPOLIER) Bowser's ghost.

[Assistant]
Pretty sure it's all based on Shinto, which is animistic, so *everything* has a ghost/spirit (which is why most things, even inanimate things, have some sort of "eyes").

It's theoretically possible that some of these spirits have never been anything but spirits, and that those might be boos.


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

[User]
Has the Hulk Buster armor ever worked?

With the latest leaked news coverage of the Avengers showing Iron Man using a brand new "Hulk Buster" suit, I wondered if any iterations of the suit have ever successfully busted the Hulk?

[Assistant] The suit itself wasn't supposed to "bust" the Hulk, it was meant as a deterrent. It's used in the event that Hulk goes a bit more bonkers than usual and they need to buy themselves some time. Stark knew it wouldn't win in a fight, but it would be enough to maybe get the Hulk out of a populated area or lead him into some kind of trap to use other means of detainment.


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

[User]
[dnd] how potentially true is the joke that tarrasque are a prey species?

In the 5e artwork of the tarrasque, its eyes are on the side of its head and it has spikes on its backside. Speaking from evolution, these are traits primarily associated with prey animals. Whats the possibility theres some CR 40 tarrasque eating horror?

[Assistant]
The eyes to the side = prey, eyes in front = predator is not especially accurate. What it really represents is monocular vs binocular vision. Binocular vision is great for coordinating movement, judging speed and distance etc.... but with monocular vision you can see more things, so it's a trade-off. Sharks, for example, have eyes to the side, relying on other senses beyond vision.

In the case of a Tarrasque, When you can blunder into a city with your mouth open and get a meal, you don't really need super specific binocular vision. They're practically land-based filter feeders.


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

[User]
Hello, smart scientists! Whats up with all these -umab suffix medicines Im seeing popping up all over tv?

Ive seen the adalimumab Humira commercials for a couple of years know (I think, or maybe 2020 just really has been the longest five years of my life). But lately Ive seen all kinds of other medicines being advertised that end in the -umab suffix. Is it from a particular chemical formula/compound family, or a particular pharmacological lab? Do they all have similar uses or functions?

[Assistant] -mab is monoclonal antibody, they are manmade molecules that mimic antibodies in your immune system. So they are often drugs that mimic binding proteins for example, to target certain cells in the body to be destroyed.


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

[User]
If you walked in a straight line around a small asteroid long enough, would you eventually increase its spin enough to walk off into space?

Basically what I just asked.

[Assistant] Under ideal conditions, you would only cause the spin of the asteroid to increase if your speed *also* increased. If your speed is constant then there will be a small change in the asteroid's rotation when you started walking, but as soon as you stopped the asteroid would return to its initial rotation. This is because the angular momentum of the system is conserved.


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

[User]
[The Matrix] Why do the people in the real world have genetic diversity?

Looking different in the Matrix makes sense since it's meant to simulate the real world.

But if humans are grown in their pods, why do they look different? Why is there racial diversity?

If they're created through conception, why not just use the same sperm and egg for everyone since it's not like you need to worry about genetic abnormalities or immune system diversity.

[Assistant] The residual self image shapes your appearance in the Matrix. If the machines just cloned from a limited pool, it would lead to an non-believable illusion, which would fail like the "too perfect" cycles.


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

[User] Why do sites like Google and Amazon need domain specific urls (amazon.ca google.ru) instead of .com always? Is it simply a language thing?

[Assistant]
It's an organizational choice they make. Their company has different set of inventory, shipping logistics, payment processors, and other logistics separated by region. They decided to divide their company traffic up among different domains to help group the regional logistics systems better.

Another reason could be corporate structure. They could have a Canadian corporation that operates the Canadian store and keeps its profits in Canada for tax reasons.

There is nothing about domains that prevents them from operating their site under 1 domain for the entire world. However, a company that large has many benefits to dividing the traffic under different regional umbrellas.


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

[User]
[Star Wars] How exactly do Jedi detect "danger"?

In Episode II, Obi-Wan and Anakin sense danger in Padm's room and find two deadly worms in it.

In The Clone Wars episode "The Unknown", a Jedi Master senses a treacherous clone about to shoot her from behind.

How exactly do they detect this danger?

EDIT: To elaborate, I don't see how they can use the Force to detect something random going on.

[Assistant]
Jedi have a vague and intuitive sense of the near future.

If they are about to feel pain, or acute stress, or get very startled, this will stand out to them from the near-future as clearly as if it were happening already. With practice and mindfulness, they can get ahead of the danger instead of just panicking early.

They also have the ability to sense thoughts and feelings, *especially* of people they share emotional bonds with. So if they, or somebody close to them, is going to go through some shit soon, they feel it early.


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

[User] Eli5: can anyone explain "crossing the rubicon?" I've wiki'ed it, so I know it's a river in Italy. Everything else is a bit too dry for me to digest.

[Assistant]
In ancient Rome, generals weren't allowed to cross the Rubicon with their troops - the idea was that the generals would sort of disband their armies before officially entering Italy, making it impossible for a general to try leading his army in a civil war or a coup.  Crossing the Rubicon with your army was punishable by death.

Well, Caesar had big ideas, and he was pretty sure that he could win a Civil War.  But still, crossing the Rubicon was the point of no return - once he and his army crossed it, they would be outlaws, and they'd either have to conquer Rome or die trying, because the alternative was execution.

So "crossing the Rubicon" now means "making a point of no return decision."  Because once you've made that tough call, there's no turning back.


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

[User]
Why don't greenhouse gases reflect just as much incoming sunlight as they trap?

The common explanation of greenhouse gases is that sunlight that would bounce off the Earth out into space instead bounces off the greenhouse gas, trapping that heat on Earth.

But if greenhouse gases simply reflect solar radiation, wouldn't they also reflect from the "outside", too, thus preventing solar radiation from reaching the Earth in the first place?

[Assistant]
Greenhouse gasses, like the glass of their namesake, are transparent to most of the visible light spectrum, but more absorbent of infrared light (ie heat radiation).

When visible light passes through the atmosphere and hits the earth, it warms up the earth, which then re-radiates that energy to space as infrared.

So hence the greenhouse gasses pass through the visible light on the way down, but block the infrared from getting back out again, so energy is trapped in the atmosphere.


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

[User]
Is to be immortal also to be invulnerable?

Alternatively, is to be invulnerable to be immortal?

[Assistant]
There is a clear difference between immorality and invulnerability.

Noah Bennet encountered both an immortal and an invulnerable "powered human" during his work with them. His daughter was immortal, things that killed her just brought her back. She was certainly vulnerable, nothing bounced off of her skin, bullets sank in, limbs came off, and she could even die, but she always came back. Immortal.

On the other hand, he went with the Hatian to take down the Hatian's brother, who was invulerable. Any "attack", for lack of a better word, on his skin bounced off. IF you ever managed to kill him, he'd stay dead, but almost every attack glanced off of him. He was not immortal, if he died while his power was turned off or from poison or old age, he won't come back, but his skin blocked attacks. Invulnerable.

The definition of invulnerable is "unable to harm or damage". People who are immortal can be harmed or damaged, but heal or regenerate it, People who are invulnerable cannot be damaged, nothing breaks off.

You're right that there are many cases where the two are more or less the same result, but that does not mean they're the same. Both powers have different weaknesses, work under different scenarios, and can be abused in different ways. If Bennet had been dumb enough to try to take down the invulnerable guy with an immortal-killing bullet to the pons, or if Syler had tried to kill Bennet's daughter through temporary supression and then a bullet just anywhere, neither would have worked. The difference is subtle, but if you don't pay attention to the subtle differences of the powers, you'll get yourself killed in the field.


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

[User]
ELI5: At what point in history did we decide cats and dogs can be domestic animals? They had to start out in the wild at first. What made us choose them over others?

At what point in history did we decide cats and dogs can be domestic animals?  They had to start out in the wild at first.  What made us choose them over others?

[Assistant]
Some wolves were friendly enough that early man learned to "trade" food with them, and in exchange the wolves stuck around and provided security and possibly even helped in the hunt. Wolves are social animals like humans, so there was a level of innate understanding that we could build on. Over time, their descendants were bred for friendliness and various working tasks... eventually, they moved right in with us.

As for cats... I've heard it described that they're the only animal that domesticated themselves. Wild cats learned to associate humans with food and shelter... eventually, any offspring that was friendlier and more domestic were kept and less friendly ones were tossed out. Over many generations, this resulted in the fat, furry, lazy bags of evil we know as domestic cats today.


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

[User]
Do your fingerprints resemble your parents' fingerprints?

Are fingerprints a hereditary trait? Do they (even vaguely) resemble parental fingerprints?

[Assistant] Fingerprints are formed due to environmental factors. Differential pressure in the growing volar pads during fetal development leads to the patterns you see. This is the reason even identical twins would have different fingerprints.


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

[User]
[Danny Phantom] so where exactly did the Fentons get their money from?

All that high tech equipment couldnt have been cheap on top of the costs of raising two teenagers in what I assume to be their privately owned building that came with additional expenses and I doubt that ghost hunting was bringing in a lot of cash for them.

So how could they afford their lifestyle?

[Assistant] They specifically mention having money due to inventions, so I'd assume they managed some patents on non-ghost related stuff. Or maybe they sell ghost hunting gear, though other ghost hunters seem to see them as a joke (or they just see Jack that way, can't recall). Not sure how profitable that reputation is.


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

[User] [Marvel/DC] What would happen if Ghost Rider used his Penance Stare on the Joker?

[Assistant]
Different tellings of each character give us different results.  So either it would wreck Joker because he'd feel all the pain he's caused, or it'd do nothing to him.

Ghost Rider seems to be one of those Worf Syndrome characters, so if it's a GR comic then Joker's toast.  If it's the prelude to something bigger than just Ghost Rider, then nothing will happen.


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

[User]
[Simpson] Why do people from Springfield who leave and go anywhere else in America not notice how weird Springfield is?.

I mean I know there are small exceptions. The existence of Shelbyville for one, but they are just as odd in their own way. The Simpson family has left Springfield of course, from Japan to Brazil to Canada, they have even stood in five states. And of course Capital city. But the only example I can think of where a major difference is noticed by a native Springfield resident is Lou mentioning the existence of McDonald's and its differences to Krusty Burger with Chief Wiggum, and a couple mentions in various ways acknowledging Springfield is consider pretty bad for a town in the US. But people have to leave for various reasons, there are all sorts of reasons to think they do, but nobody ever seems to come back to Springfield at all confused by any of its ways or customs.

[Assistant]
Probably the closest anyone has come to comprehending how f'd Springfield is was Frank "Old Grimey" Grimes... and the revelation drove him to madness and killed him.

Then again, America elected Rainier Wolfcastle to the presidency. Presumably, the rest of the country isn't that much saner.


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

[User] ELI5: Why are fighter jets so much louder then standard aircraft e.g passenger, cargo planes etc?

[Assistant] Fighter jets have low bypass turbine engines. Passenger aircraft have high bypass turbine engines. High bypass engines used the turbines that turn big fans in the front. This are goes around the engine instead of through it. So its like a big room fan. You are hearing more of the rushing air vs the burning gasses inside the turbine. In a fighter jet, the majority of the air is consumed through the turbine and mixed with burning fuel. That burning of the fuel makes the noise you are hearing.


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

[User]
[Elder Scrolls/Morrowind] Were there any consequences after the complete looting of the Census and Excise Office in Seyda Neen?

Even the buckets and torches were taken! Surely this was a breach of security, a known criminal was allowed to wander around the office with no escort, and wasn't even searched before leaving. In fact I heard a rumor he stole a very expensive limeware platter while a guard and census officer watched! Boy I hope someone got fired for this one.

[Assistant] (upvote for a question that can't be answered using 'Speedforce').. If memory serves, that office was wracked with troubles at the time as it stands. Tax collector murdered, accusations of corruption and guards shaking down citizens. Add to that the whole corprus situation and the fact that this predates the Miracle of St. Jiub and we're lucky to have any records of anything other than 'how many billions of cliff racers we saw today'.


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

[User]
[Star Trek] Trying to figure out the limits of Borg adaptation...

In First Contact, Picard manages to off a few Borg using fake bullets on the holodeck.  For some reason this seems to work better than phasers.  Whatever. In any event, someone on this sub once stated that the Borg would eventually adapt - even if the bullets were real.  This leads me to my real question.

Let's say that you have an army of advancing borg, and a thousand or so heavy things (tanks, 18-wheelers, filled shipping containers, etc.).  You also have Hulk standing there, mindlessly flinging heavy shit at the Borg incessantly.  Will the Borg ever adapt or does this strategy always work?

[Assistant]
The Borg were not expecting to be hit with a kinetic projectile based weapon in an era when energy weapons are almost exclusively used. Given time the Borg could implement kinetic shielding to slow/stop bullets or other projectiles.

Adaptations are usually give and take situations so it would be possible that defending against kinetic based attacks weakens them to energy weapons. Given enough force or power you could still defeat them. The effectiveness of Borg defenses against kinetic damage will likely come down to how much energy they can put towards defense vs how much we can put into offense.

The Borg also require that their organic parts remain functional to hold the augmented cyborg parts in place. While the organic parts of the body are enhanced they are not impervious to damage. If you can destroy the organic parts you can destroy the Borg. This may be capable with extreme heat, biological agents, chemicals, nuclear warheads.


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

[User]
If time is measured using mechanical or atomic means, traveling in a very fast reference frame, why is it that time itself slows down instead of the operation of the component used to measure time?

Is it just how time is defined, by its measurement?  Why isn't it just that these time measuring devices' operation is affected by going super fast instead of the nature of time itself?  For example, the gears moving in a clock just move more slowly instead of time slowing down.

Not sure this is worded correctly so hopefully my point gets across.

[Assistant]
A muon is an unstable subatomic particle. You can think of it as being kind of like a fat electron. They're produced in all sorts of scattering events, but once they appear, they tend only to hang around for about two millionths of a second before decaying into an electron and a pair of neutrinos.

Muons are produced very frequently millions upon millions of them a second  in cosmic-ray interactions. A high-energy proton comes screaming out of space and intersects our atmosphere. It scatters off a gas molecule and decays, and one of the decay products that can appear is a muon.

Because muons only last two microseconds, we shouldn't detect any at sea level. They should decay long before they get from the upper atmosphere to the ground.

But we do detect them. We detect *thousands* of them per square yard every minute.

How can this be? Because the muon is time-dilated by virtue of how fast it's moving relative to you, sitting on the surface of the Earth. In its frame, the muon only lasts for about two microseconds, on average, before decaying. In the frame of a detector at sea level, it lasts much longer.

So no, it's not about clocks. It's about time itself.


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

[User]
[Star Wars] Can you be on the light side of the force and be evil?

Was mulling over the idea of writing a evil light side user in a Star Wars fan fiction. I was thinking since the Dark side was fueled by strong emotions like anger, fear and hatred; what if you have an emotionally warped character that displayed none of those emotions but their actions were still morally wrong. Like they are a non-human being with force sensitivity but a completely different sense of morality and values from humans and other races; or there's something broken in their mind that prevents them from empathizing or understanding that their actions are wrong; or their complete emotional detachment has left them becoming moral pragmatists that think only in terms of cost, loss and benefits; or maybe their bad in the same way that the law routes in a Shin Megami Tensei game can be bad (i.e. preserving order and peace at the cost of one's freedom). Am I on to something, or does this completely contradict Star Wars lore?

Edit: I should mention something, when I mean light side I don't necessarily mean Jedi. Like obviously the Jedi won't accept a sociopath into their ranks, so this character may still utilize the light side of the force but not be associated with them.

[Assistant]
There was that group of Jedi who plotted to murder a whole class of Padawans. One of them had a vision that one of the Padawans was going to become a Sith Lord that will destroy the whole galaxy.

Turns out the whole thing was a Dark Side plot, and they caught the Sith responsible. He was very good at lightsaber fighting so they just bombed him from space.

None of the Jedi in the plot thought they were evil, they thought they were doing what was necessary to save the galaxy. But suffice to say, they had abandoned their Light Side principles without even knowing it.


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

[User]
Sexually monogamous-type breeding strategies are not-uncommon in a number of species. Are there any non-human species where infidelity results in conflict between the breeding pair?

In this case, 'infidelity' is where one or both members of the breeding pair copulate outside that pair, and 'monogamous-type ' includes serial monogamy.

[Assistant] There are many species of monogamous birds where you see cheating happening along with consequences. Bluebirds mate for life, but it's been documented that females will cheat on their mates if they are less desirable for whatever reason. They will sneak away to the territory of a more desirable male, who's happy to take her up on it. But, if she is caught by the male she's mated to, he will leave her and refuse to help raise the offspring she has later. They will both then look for new mates.


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

[User]
CMV: Late term abortion (third trimester) should ONLY be allowed if the mother's life is at risk.

I think the abortion debate is very complex. Both sides have very compelling points. At some point a clump of cells does become a human being. At the same time, I believe women should have rights to their bodies. I lean pro-choice, but draw the line when it's clearly a developed baby.

By third trimester it's sentient and can feel pain, there's hardly a difference between killing a baby that developed inside the womb opposed to killing it after it's being born. It's first breath is just a subjective moment to draw the line.

I think that there's no reason to kill it that late in pregnancy, **unless the mother's life is in danger making it an unfortunate necessity**. If there are any other reasons for choosing abortion, it could have been done at earlier stages before the developing baby gained sentience, so there's no excuse.

**Beyond the uncontrollable and unfortunate circumstance where the fetus poses a threat to the mother's life:** I can't think of any justifiable reason why someone would wait until the fetus is developed into a sentient baby, then abort. "Because it's my body and I can do whenever I want!" is doesn't cut it when it's become that developed, that excuse wouldn't fly killing it right after birth. With that rationale abortion should have happened at earlier stages. That's where I draw the line on my pro-choice views, perhaps you can change them?

*View altered:* Two deltas awarded so far (may be more as I read), thanks everyone for the good discussion. Roughly 75-80% of commenters have been respectful and it was a good talk! Most of my experience on Reddit has been rude people, so this was a nice change.

[Assistant]
It's not complex.

Late term abortion is a misused term.

There are 40 weeks in a normal pregnancy. The latest abortions go up to 22 or 24 weeks, which is incredibly rare. Most places only allow and most abortions are performed before 13-16 weeks.

Any later and it's purely a procedure because the mother's life is in danger.

Anybody trying to tell you otherwise is lying and trying to gaslight you into believing something inane like 'they are killing newborn babies'. Which they aren't. Ever.


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

[User]
[Star Trek] Can the Borg actually assimilate any biological abilities? Or just technology?

"We are the Borg. Lower your shields and surrender your ships. We will add your biological and technological distinctiveness to our own. Your culture will adapt to service us. Resistance is futile."

Chilling words, but how much is true and how much is meaningless boasting? As far as I can tell, they don't add any biological distinctiveness to the collective. The biological organisms they assimilate don't seem to be used as anything more than corpses adapted to carry the borg's advanced technology.

I suppose the drones' extreme strength and lack of dying of old age could be partially biological adaptations, but they're almost surely augmented by technology. We know that the Borg are simply unable to assimilate some races with bizarre biology like Species 8472. It also seems like they've never assimilated other biological abilities like the psychic powers inherent in Betazoids, Vulcans, etc. Thank God.

Are there *any* biological abilities that have been assimilated? Even on a microscopic scale? Or are the Borg only after technology and not really interested in biological distinctiveness on anything beyond a cosmetic level?

[Assistant]
The Borg do alter the genetics of the assimilated lifeforms, these artificial Borg genetics are a combination of the most desirable traits found in the assimilated lifeforms to date, new traits can be added once found and deemed useful. The alterations idealise the biology of the assimilated lifeform for assimilation, implantation, and service.

The Borg use both biological and non biological alterations to augment the drones.
Biological alterations serve to create the ideal base for cybernetic augmentation, and to turn individualistic specimen into hive drones harmonized with the hive mind.

Observed changes in the biology are a uniform biochemistry, thus adapting all drones to the same life support conditions, and the psionic capacities used for communication and vessel regeneration.

>We are the Borg. Lower your shields and surrender your ships. We will add your *biological* (true) and *technological* (mostly recycling, but sometimes interesting ideas are picked up) distinctiveness to our own. Your culture(what little is not deleted/suppressed. It is more efficient than saying 'species/race/faction/alliance/political and or biological unit/whatever/organisation that builds and/or controls what we are about to assimilate') will adapt to service us. Resistance is *futile**.

*^(one cube short of being true)


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

[User]
[The Matrix] If the humans hadn't blocked out the sun in an attempt to cut off the machines from the energy the sun was providing them, what changes?

Essentially it was this that led to the machines developing humanity itself as the machine's primary power source. This of course includes the development of the matrix itself.

So how would things have gone differently? Would the matrix exist as it does as a result of operation dark storm?

[Assistant] You should really watch the Animatrix but to summarize if the humans had stopped being huge stupid asshats nothing would have happened, the robots would have just lived on their island peacefully trading and putting out diplomatic efforts, learning and growing, helping upgrade humans, and eventually transhumanity would have traveled the stars together without any sign of who started as what.


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

[User]
[MCU/Netflix] What are the rules for being a vigilante?

In Season 3 of Daredevil, it's made to seem that if the FBI finds out the truth that Matt is Daredevil, there would be serious jail time for both him, as well as Foggy and Karen (as accessories). But what has Matt done that others haven't?

Take Luke Cage for example. He is extremely public when it comes to his abilities and activities, even attempting to sign deals with Nike as a spokesperson. The police keep saying that they do not condone what he does, but they make no attempt to arrest him for vigilantism.

In No Way Home, while Peter is accused of murdering Mysterio, the charges from the Feds were later dropped. But he is still well known for taking the law in his own hands, but he was never charged. So what makes Matt different?

Sure, I guess he could be disbarred, but that has nothing to do with going to jail. Sure, Matt was framed by Fisk during the whole FBI ordeal, but Foggy made it clear, even beforehand, that if the FBI finds out the truth about Matt, then they will be arrested.

So what's the deal?

[Assistant]
Luke Cage doesn't seem to cause as much harm as Daredevil. He just absorbs bullets and knocks people out occasionally. He's had a visibly positive impact on the community, so he's not worth going after.

Peter probably gets off for the same reason. Not only is he generally just "the friendly neighborhood spider-man," he also has a ton of goodwill for saving half the universe.

Bonus: it's also much clearer that those two are super heroes, as opposed to a crazy guy running around Hells Kitchen.


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

[User]
ELI5- Credit Card Fraud. How did my credit card get used at a gas station? And a pharmacy? And a Target? 200 miles away.... When it is still in my wallet?

How does this sort of fraud work? Where did they get the credit card number? How did they use it at these places without a physical card? Can anyone break down the process for me? I'm just curious.

[Assistant]
At some point while you were out, the information on your credit card was copied. The attacker probably made a fake duplicate card, and then began making purchases elsewhere. Info in the magnetic stripe on cards is not encrypted, and can be easily read with a magstripe reader. The magnetic stripe contains the same information that is printed on the front of the card.

Last December, a large volume of credit card information was stolen from Target - this is on the large scale. It happens on the small scale also when a local business stores customer information in an insecure fashion. I've also heard stories of dishonest cashiers or waiters who have stolen customer card information to then sell it on the internet.

EDIT: Like the other replies said, definitely contact your credit card company and report the charges as fraudulent. They'll send you a new card and you won't be charged for the fraudulent purchases.


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

[User]
[Star Wars] How were the ewoks able to defeat the stormtroopers on Endor?

Their arrows don't seem able to actually do any damage to the Stormtroopers armour.

[Assistant]
The Ewok species is perhaps one of the more dangerous forces in the less-traveled sectors of the galaxy.

Consider, first, their intellect. Barely into their Stone Age, they have invented rudimentary flying machines and siege weapons, also harnessing the powers of the arboreal habit in which they thrive. They seem to have a natural inclination for advanced technology, as well - theft of speeder bikes was not uncommon, and if word from communications operators overhead during the Battle of Endor is to be believed, they even commandeered a scout walker to great effect.

More dangerous than their minds are their bodies. Whomever selected their homeworld as a suitable base failed to properly quantify the weight-to-muscle ratio of the average Ewok; indeed, simply *looking* at an Ewok can make it difficult to gauge their strength. Harmless by appearance, the Ewok's limbs are packed so thoroughly with muscle that they have limited flexibility in their joints. They are slow, but easily as strong as a Wookiee, and more lethal for their innocuous demeanor.

Perhaps a greater threat to the Imperial forces on Endor during the battle was the complete lack of competence of the command system - a legion if troops wearing *plastoid* armor won't fare very well against the sort of enemy that can put an arrow through a tree. The hubris of the command not to fire-bomb the forest once the shield bunker was penetrated proved disastrous for the Empire.

There is good reason that the sentry moon of Endor has been labeled as a Hazard Level VI. People go to the Ewoks looking for teddy bears; what they forget is that the Ewoks **are** bears... hyperintelligent, zealous, all-muscled **bears.**


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

[User] ELI5 How does Snapchat know I took a screenshot?

[Assistant]
This is a sensible question because the physical buttons on your device generally interact directly with the overarching OS (the home button, the lock button, the volume buttons, etc) all appear to deal with the phone directly, and not the individual apps, so it makes sense to wonder how the app itself notices.

However, the operating system still provides 'hooks' for apps to link their functionality into these button presses, and where applicable, override their normal functionality.

For example, in IOS the volume-up button is override by the camera-app, as a shutter-button.

Also in IOS, a screenshot is taken by pressing the home and lock buttons at the same time. Now, if snapchat were to '*override*' the functionality (replace it with something else - like your phone makes a fart  noise instead of going back to the home screen) then it would likely render your phone unusable (as you'd be stuck in the app, without a back button) and thus would likely not be allowed in the IOS appstore.

However, if it listens for the event (the home/lock button being pressed), does some stuff, *then* allows the normal function of the home/lock button to go ahead in a timely fashion, then the appstore will allow it.

Normal use of this would be to gracefully handle the closing of an app (e.g. to save stuff you're in the middle of so it can be resumed later)...snapchat just uses this millisecond to process "The home button is pressed - is the lock button pressed simultaneriously? IF yes, record that a screenshot was taken, and notify whoever's currently on screen, if not, invoke the normal back-button process"

Make sense?


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

[User] ELI5: when we walk or press surfaces hard are we killing viruses and bacteria like some unseeing giants of a microverse or are they too small for us to physically affect?

[Assistant]
Yes and No.  Bacteria are small enough that the surface of the bottom of your shoe (and the surface you are walking on) are full of relative valleys and troughs - very much large enough in which to be kept away from the crushing forces.

That said, it's certainly true that some are killed - e.g. that bacteria sitting on the peak of a spot on your shoe hitting the peak of the concrete will get crushed.  But...the million brother bacteria right next to it are left fine.

TL;DR: don't use a fly swatter to wash your hands clean of bacteria.


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

[User]
[Star Wars] What did Admiral Ozzel do to warrant Darth Vader killing him when they arrived at Hoth?

I would think the faster they blockade the planet the more Rebels would be caught especially since resources and manpower are limitless in the empire.

[Assistant]
They weren't looking for a blockade, they were looking for destruction.  Bringing the fleet out of hyperspace close to Hoth allowed the rebels to detect their arrival and raise their powerful shield, necessitating a ground battle and leaving time for ships to escape.
An undetected arrival and stealthy approach would have allowed the destruction of the shield generators and subsequently the entire base via orbital bombardment.
Basically Ozzel wanted a surprise attack but his tactics caused the opposite.


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

[User]
ELI5: Why do we enjoy depressing/sad stories (movies, books, gamers, etc.)?

Is it because they make us feel better about our own problems or what?

[Assistant] Yes, they help us notice our own sad feelings, which we often push aside. Looking at *someone else* being sad is sometimes more tolerable than directly confronting a sad thing in our own life that we need to notice.


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

[User]
[Spoilers][Star Wars] In canon, is Darth Vader still in constant pain?

Before canon it was stated in "Legends". That he was in constant pain, the suit was uncomfortable and purposefully so, since Palpatine never wanted Vader to reach his full potential.

But now that it's no longer canon, and in R1 Darth Vader now has a castle, and inside of this castle he has his own cozy bacta tank, so does this mean his suit is still painful to wear? Or is it just to have a moment of bliss?

[Assistant]
Yes,  see the novel Lords of the Sith:

"Vader completed his meditation and opened his eyes. His pale, flame-savaged face stared back at him from out of the reflective black transparisteel of his pressurized meditation chamber. Without the neural connection to his armor, he was conscious of the stumps of his legs, the ruin of his arms, the perpetual pain in his flesh. He welcomed it. Pain fed his hate, and hate fed his strength.Once, as a Jedi, he had meditated to find peace. Now he meditated to sharpen the edges of his anger"


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

[User] Two gorillas were just diagnosed with Covid in CA. What does Covid look like in animals and can a disease, like covid, pose a significant risk to a specieces if there is rapid transmission?

[Assistant] I think the answer is obvious.  No species, other than humans, ha e the remotest chance of developing successful strategies to deal with a pandemic. Pandemics occur regularly in nature. The population in many species is affected in predictable cycles by disease. Google varying hare population variance


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

[User]
[The Road To El Dorado] 2 things about the movie that doesn't make sense

In the scene where Miguel and Tulio tried to convince the people of the city that they were god's, a volcano nearly erupted and when Tulio screamed "Stopped" it stopped erupting convincing them that they were Gods. Exactly what caused the volcano to erupt in the first placed and what caused it to stop from erupting?

And during the ball game where the armadillo was shaped like a ball it somehow flew or levitated itself all the way up and through the hoop multiple times for Miguel and Tulio to win. How's that?

[Assistant]
>Exactly what caused the volcano to erupt in the first placed and what caused it to stop from erupting?

Coincidence. Or the actual gods thought it'd be funny to let them have this one. Take your pick.

>And during the ball game where the armadillo was shaped like a ball it somehow flew or levitated itself all the way up and through the hoop multiple times for Miguel and Tulio to win. How's that?

It bounced up the wall.


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

[User] ELI5: why are two headed reptiles more common than two headed mammals?

[Assistant]
Reptiles on average have more offspring than mammals and reproduce by laying eggs. Animals in eggs are more susceptible to environmental conditions which may affect the embryo inside.

Being two-head, which is called bicephaly, can also result from an embryo splitting in two (this is how twins form) but sometimes they don't split completely and this is how conjoined twins form.


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

[User]
ELI5:How does the middle income trap work?

My understanding is that the middle income trap describes countries that have risen from extreme poverty, but not into first world status.  Malaysia is often cited as a textbook example.  What is the prevailing though of why this happens.

[Assistant] when you have an economy that has a lot of workers that can be fairly low-paid workers (compared to more 'developed' countries), companies will start up factories there to take advantage of the lower costs. The people working there will happily do so because the pay is better than might otherwise have happened, so everybody seems happy. This influx of money creates a 'middle class', who aren't rich exactly, but have more money than the traditional working class. Wages increase (as they usually do), but eventually, another country is able to provide a workforce that is cheaper again which means the upward mobility in the original country stalls.


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

[User] ELI5: Why does some tap water have so many small air bubbles that it looks like its actually white?

[Assistant]
I think OP asks the milky white type of water that takes some time to clear up.

That's caused by the pressure in the main pipes. Water needs pressure so it can travel from the reservoir to your home. Increasing pressure makes air more soluble and it mixes in easily. Once it is near your faucet, the water loses pressure and the dissolved air separates, leading to super small bubbles that create a milky white appearance as these bubbles also disperse light (similar to fog effects).


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

[User] in the United States most northern states use substantial quantities of salt to de-ice roads and walkways; what impact does this have on the surrounding environment?

[Assistant]
Geochemist from Minnesota:

It has an effect, but since much of the salt is only washed away when the snow melts the majority of it ends up in the storm water drainage systems. This system is designed to take water that is contaminated with all types of road/yard chemicals and keep them out of sensitive waters so the salt works along the same principle. Also, the only way the salt can move is to be dissolved and a long as it stays dissolved until it makes it down into the water table it isn't going to do much.

Just one note is that the salt used here doesn't seem to have a very large impact on the fertility of the trees/grass directly along the road sides so unless you were to get a large puddle of salty water evaporated in a location the concentration of salt would still be within the tolerances of most plants. Remember that sodium and chloride are very common ions to find in nature.


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

[User]
[Marvel] Did Spider-Man ever become bloodlusted or had murderous intent?

99/100 Fights, Spider-Man very rarely goes all out with his strength, I mean the dude can lift buildings, stopped a max speed train, was officially stated to have precognition or at least some form of precognition, and was so strong he punched scorpion's jaw clean off like walking dead style jaws off, was capable of stunning heavy hitters like Morlun, Rhino and even Hulk with his regular punches, assraped Kingpin while slightly serious.

I think the closest times where Spider-Man ever became close to Bloodlusted is during his fight with Kingpin after his failed assassination and accidental mortal wound on Aunt May, fighting villains while the Symbiote Suit was on him, Superior Spider-Man during the beginning of his storyline.

[Assistant]
Actually, there's at least one storyline where Kingpin very nearly crossed the line.

After Aunt May was severely injured by a gunshot in an attack meant to harm him when Fisk learned his real name (I think this was around the time of Civil War) then proceeded to *gloat* about it, Peter showed up *without his costume*, broke into the prison Fisk was being held in then showed that he normally holds back when fighting Fisk... by beating him so badly that he left the 400lb man lying in his own blood. Then made it clear that if May doesn't pull through, he's going to come back, beat the shit out of Fisk *again* then he's going to shoot entire canisters of webbing down Fisk's throat until his lungs are filled so that the fat bastard can choke on them.

Do *not* harm someone he cares about.


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

[User]
ELI5 Why can lungs not heal themselves from silicosis?

Why are we told that after we quit smoking our lungs are "self-cleaning" and will heal after the pollutant is gone, but told that for silicosis the damage cannot be reversed?

[Assistant]
Silicosis damage is caused by breathing in dusted crystalline silica. Basically, tiny shards of glass. This stuff shreds your lung tissue and your lungs heal by scarring.

Most contaminants we get exposed to like this dont actually cause that kind of physical damage. They just stick to the interior of the lung, blocking oxygen from being absorbed and introducing chemically dangerous things to your body. But once exposure has stopped, filaments in the lung called cilia push the contaminants out.

Silica shreds the tissue and leaves scarring that prevents lung function. That scarring doesnt go away, even when the silica is long gone.


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

[User] [Marvel/DC] What if Captain America found himself in the DC universe? What would his role be?

[Assistant]
There was a great Batman/Captain America crossover [John Byrne]

That said; Cap would be Cap.  He'd hook up with Allan Scott and Jay Garrick and roll with the JSA instead of the Avengers.

In fact, I'd like to see a Captain America Legion of Super Heroes cross-over where he's sent to the future to help train the newest recruits.


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

[User]
CMV: People don't talk enough about how the media - through commercializing love and sex - contributes to movements like the incels

Nowadays a topic that often comes up is how we shouldnt judge people (mostly woman) because of their sexual lives - whether that means having lots of past partners, or very few. This is obviously a good thing, but I feel like a key factor that often gets overlooked in these debates is the role of the media, and how it feeds into the insecurities of some people, which, in turn, may lead to repressed anger.

In my experience, one of the biggest reasons leading to young men judging woman because of their sex lives is their own insecurities. I have experienced this in my mid-teens, and I've seen other friends go through this same thing a bit later in life (like their early 20s): at a certain point, many single people - especially virgins, though not exclusively - begin to project their own desperation onto others. If they're a virgin, they project that onto women with active sex lives, and deem them "sluts". If they've been single for too long, they project that onto women with active dating lives, and call them "easy whores" or whatnot. This is an unhealthy coping mechanism, but at it's root is an issue still largely unresolved: the role of the media.

I have been in situations where I alsmost fell down the self-pity incel rabbit hole. I was (and to an extent, still am) extremely insecure about being a virgin in my 20s. People have told me that I shouldn't worry, it's okay, it's actually very common, and they are right, statistically speaking. Yet, this didn't help much when I turned on the radio, and every song is about love, sex, women, etc. Nearly every show has romantic subplots, ESPECIALLY the ones featuring young people. Nearly every YA book is filled with people finding the love of their lives in their teens.

This is obviously unrealistic, people shouldn't have their real life expectations based on works of fiction, but many people - including former friends of mine - really can't get over this. They're getting closer and closer to the incel subculture, because they can't reconcile with their own lack of success, while everywhere they look, every show, book, ad, billboard, etc. is full of sexual messages. It further puts sex on a pedestal, which inevitably feeds into people's insecurities about it.

[Assistant] I don't think I've _ever_ seen a long-form work about incels that does not mention media as central to incel communities and the incel movement. Why do you think that people don't talk enough about how media has fueled this movement?


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

[User]
[Star Wars] How powerful in combat are average Jedi/force users compared to skilled non-force sensitives?

Excluding above average/the chosen one type Jedi and force users such as Anakin, Obiwan, Yoda and Sidous etc. How powerful would an average Jedi trained during the Republic be against a well trained and skilled non-force sensitive in a 1 on 1 combat situation?

[Assistant]
With tech (like jetpacks, body armour, and light sabres) someone like Jango Fett held his own pretty well against one of your ABOVE average jedi: Obi Wan.

With nothing but bare hands, and assuming both combatants are of the same race (ie. not Wookie vs. whatever Yoda is), then it is probably still relatively even. Yes a force push or jedi-mind-trick will give someone an edge, but so will real combat experience.

Skill and experience, either from Jedi training or from any other "mundane" lifestyle is probably about equal.


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

[User] When I'm driving and "zone out", how do I still arrive safely at my destination even though it feels like I wasn't concentrating at all?

[Assistant]
Driving is not an intense task. Once you're used to it, it is almost as simple as walking; you simply do not need to actually think about most of what's going on.

Memory is triggered by novelty. If you see something new or interesting, you are more likely to remember it. Conversely, if you see something you've seen dozens of times before, unless something unusual happens you are unlikely to remember it. A person who drives 10000 miles per year, and has done so for the last decade, will have in that time spent around 2500 hours on the road. Truly novel experiences on the road will be very rare.

In short, you are probably paying all necessary attention to the road as you drive. However, you don't bother forming memories of the experience because you have done it all before.


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

[User]
Tension in Ph.D. cohort?

Please redirect me if my question is better suited for another subreddit. Thanks in advance!

I am a first-year student in a three-year Ph.D. program. As is expected, my small cohort was friendly before breaking off into a small group and a few assorted individuals who prefer not to socialize. Everyone has preferences and I dont think anyone expected to be close friends throughout the whole program, given its short timeline and intense nature.

However, there is considerable tension between a few people (seemingly based on performance, but we are not fully sure) and it is coming out in strange ways.

In one class, our final presentation grade is an average of your peers scores of your work. The professor has stated from the beginning that s/he will not intervene. Today, we received scores and two members of our class (of 5 people - so their scores count for 50% of the grade) failed everyone else.

Aside from being extremely petty, I am angry that these people seized the opportunity to tear every other person down. I know I cant remedy the grade; grades dont matter as long as you get credit for the class; etc. But. Given that we have to deal with each other for at least two more years (if they dont drop out), what is your advice for mitigating tension and/or unnecessary competitiveness?

I have been told to use it to fuel myself, to ignore it, etc. But I work really damn hard and it eats me to see my grades suffer because of personal issues so I am truly struggling with that part.

[Assistant]
Yeah, I've never heard of this type of grading and it seems like a colossally bad idea. I'd bring it to the professor and ask for his/her assessment of your work. If it doesn't align with the assigned grade, I'd expect him/her to change it. Your professor is the expert on the material, not the students.

Then again, I've never heard of a 3-yr PhD program in the US, either.


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

[User] Why are some roads made from concrete/cement rather than asphalt? What determines whether it should be one or the other? Why do a lot of the cement roads have grooves in them?

[Assistant] Cement roads are significantly more expensive. Asphalt is the cheaper option and actually has a better safety rating due to more traction. The grooves are used for better road traction or to extend the life of the road surface.


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

[User] ELI5: How is it that crows can be as intelligent as a 7 year old kid, but their brains are so much smaller? What is the correlation of brain size to intelligence?

[Assistant]
Crows can do some things as well as a 7 year old child, not all things.  They certainly can't control a child-sized body with the broad spectrum eyes that a child has.  They can't control the complex vocal mechanisms like a child can.

They can do about as well on some types of intelligence tests, that's far from doing everything as well.  At the very least they lack a 7 year old's ability to learn and process abstract ideas like calculus.

On the other hand, they can control their bird body, and **they can fly**, which a child certainly cannot (no matter what they think).  They are just not very much like a child, so they need a very different brain.


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

[User]
[Narnia] How do Peter, Susan, Edmund and Lucy adapt so quickly to being children again?

I've encountered adults trapped in the bodies of children before and you can generally tell that you're not dealing with a child.

But these guys can spend decades as rulers of a magical land then drop straight back in to the same bodies and routine without so much as a temper tantrum.

[Assistant]
They were not children who grew up to adults, and then suddenly reverted back to childhood.

They were children who played the parts of adults, but Peter Pan style, they were still children. This is one of the reasons Susan never marries her many suitors (*A Horse and His Boy.*)

When they do grow up, they change as people. Susan loses interest in Narnia, deciding instead to put away childish things and embrace a more adult world.

They were never adults in Narnia because Narnia isn't for adults. It's for children.

Adults trapped in the bodies of children don't go to Narnia. Children trapped in the bodies of adults, however, can.


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

[User]
[EU] Assume that the hyper intelligent lab rat, The Brain, manages to actually take over the world for a long term reign without any goofy shenanigans occurring. What is his actual goal and how is the world affected?

I'm aware that he managed to take over the world temporarily a few times but I believe Pinky or the world population managed to screw it up before he managed to actually enact anything.

What is his actual end goal?

[Assistant]
There was an origin episode. ACME Labs was trying to make intelligent mice. When they tested Brain, he zoned out. Once it was over, he decided to take over the world so people would respect him.

I have no idea what he plans on actually doing, since once he takes over the world respect is a given. He'd probably just try to get things to run smoothly. And fail horribly.


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

[User] ELI5: Why is "nonchalant" a word, but "chalant" is not? Are there other English words like this?

[Assistant]
See the other answers for nonchalant/chalant.

There are other English words  like this; they're called *unpaired words*. They include:

* debunk
* defenestrate
* dejected
* disconsolate
* disdain
* disgruntled
* dishevelled
* dismayed
* disrupt
* feckless
* gormless
* impetuous
* impromptu
* inane
* incessant
* inchoate
* incognito
* incommunicado
* indomitable
* ineffable
* inept
* inert
* infernal
* inhibited
* insidious
* insipid
* insouciant
* intact
* invert
* misgivings
* misnomer
* nonchalant
* noncommittal
* nondescript
* nonpareil
* nonplussed
* unbeknownst
* ungainly
* unswerving
* untold
* untoward

EDIT: thanks for the gold!


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

[User]
[Injustice: Gods Among Us] Let's say ALL the nations of the world turned against evil Superman. Is he really powerful enough to fight them off? Does one Kryptonian really equal the might of Earths militaries?

The game makes it seem like evil Superman conquered the earth because Superman > the combined militaries of every country. I find this VERY hard to believe. Did he only conquer the earth because he had the Atlanteans, Themyscirans and Khandaqians on his side?

[Assistant] No.  That's why he got a bunch of other super beings as his lieutenants.  The combined might of Superman, Wonder Woman, Green (now Yellow) Lantern, Sinestro, Cyborg, Deathstroke.  And yes, the Atlanteans.  Atlantis has the greatest navy on Earth by a wide margin.


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

[User] [The Purge] During the Purge, what do people on flights over the US do? If someone is murdered on a flight to Canada, does Canada honor the Purge?

[Assistant] 12 hours before purge night all flights into and out of the US are grounded for 24 hours.  Incoming flights are redirected to nearby airports in Canada Mexico and Cuba.  Aircraft are strictly forbidden from being used as weapons or targeted on purge night punishable by death from federal agents and not exempt.  International visitors are recommended to seek shelter in their embassy or designated areas until after purge night.  Anyone killed during purge night that's a foreign national will be fairly compensated for their death by the NFFA to their parent nation or family.


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

[User]
[General] why are magic from an bygone era stronger than magic from the current era?

this seems like a very common thing in fiction involve magic,for example harry porter and the elder scroll series, ancient magics are way more powerful than the current magic. You would imagine after all those years, magic users would have more time to study and improve their spells. It seems magic is the opposite of science which improve over the time. I mean you would not trust a cure for herpes from a 3000 year old medicine book.

[Assistant]
The biggest problem with this question is that it depends on the universe and source material. There is no definitive answer. So here are a few of the more popular reasons that have been given.

- Entropy. Primordial magics fade over time, so over time magic just gets weaker.

- Lost Art. Its as simple as people have just forgotten how to do the cool stuff.

- Limited Resources. Similar to entropy, except magic comes from certain places/things and there are less of them now, so less magic in general to go around.


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

[User]
CMV: Too many parents treat their kids as objects to be put on display/invested in instead of as people.

And I'm not even talking about those school-age beauty pageants. I'm talking about in the academic and prestige sense. It seems to me that a lot of parents expect their kids to be something they can be proud of in the same way one would be proud of having the newest iPhone, or a fancy car or big house; something to be used to impress/one-up your peers and have tailored to be exactly what you want it to be. At worst, this can develop into a nepotistic sense of wanting a 'miniature clone' of yourself to helicopter parent into meeting your own unfulfilled dreams or reach an unrealistic level of success (congratulations mr and mrs x, it's a CEO!).

Consequently when and if those kids leave home and decide to follow their own path, the parents act like they've been ripped off. The fact that parent culture seems to promote bragging about your kids' grades or accomplishments like they're yours (I think there may be a gender bias in this regard, but I'm probably wrong) doesn't help either. If you're going to bring a new life into the world, you need to understand that said new life is theirs to live, not yours.

[Assistant]
Think about the opposite of this scenario:

Your parents don't give a shit about anything you do. They don't celebrate your accomplishments, they don't care about your awards, they don't even care if you succeed or not. To them you're just a kid taking up space and costing them money. You're just another person to them - a burden until you turn 18. They don't brag about you ever, they don't even talk about you to their friends and family. You're just.... there.

Is that the correct way to raise a child? No. Surely it's not. Which of these scenarios is worse for the child to experience: Extreme indifference, or extreme investment/pride?

Child development actually has an answer: It's far worse for development to ignore or neglect a child than it is to celebrate them and be proud of them. Is your scenario also bad? Yeah kind of - it implies some bad parenting traits.

But a whole lot more children will do just fine under that parenting model than otherwise.


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

[User]
ELI5:Why does bar soap seem to dry out my skin, but liquid soap doesn't?

I've recently started using bar soap again for the first time in like a decade, and noticed that even while in the shower, it seems to leave a "film" or just a sense of dryness on my skin. But I've never noticed this with liquid soap, or body wash. What is causing this? Are the two types of soaps significantly different?

[Assistant] Liquid soap isnt soap technically, but actually synthetic detergents dissolved in water.  These were invented in the 1950s when oil was scarce for making soap.  While soap and detergent are both technically surfactants, in that they are hydro and lypo philic, soap is usually very alkaline, more so than detergent, and your skin has a slightly acidic oil barrier.  When alkaline soap interacts with your acidic oil barrier, its very good at breaking it down, removing your skins ability to keep water in making it feel dry.  Liquid soap most definitely can dry out your skin, but most liquid soap has added humectants like glycerin that help to preserve the acid barrier during cleansing.


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

[User] ELI5: Why do we need sunscreen when our ancestors didn't? Did all our ancestors die of skin cancer?

[Assistant]
Ancestors that lived in Africa had lots of sun, and didn't need sunscreen because of high melanin levels.  Ancestors who lived at higher latitudes (we're talking about youall in Sweden) had clothes to protect them from the sun and lighter skin color.

Ancestors that die of skin cancer after they've had children don't matter, from an evolution point of view.


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

[User] Later this year, Cassini will crash into Saturn after its "Grand Finale" mission as to not contaminate Enceladus or Titan with Earth life. However, how will we overcome contamination once we send probes specifically for those moons?

[Assistant]
The goal is not to avoid any possible contamination - if we would do that, we wouldn't send probes at all. Possible contamination should be as unlikely as reasonably possible. If we can let a spacecraft burn up in the atmosphere of the gas giant, that is done.

A lander cannot do that, of course, so it will get sterilized as good as reasonably possible.

The Mars rovers avoid regions where liquid water temporarily could exist underground today, for example.


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

[User] ELI5: how does a fit bit know when you are asleep and what stage of sleep you are in? How accurate is it?

[Assistant]
it tracks your movement while you sleep.  If the wearable has a heart rate monitor, it uses that as well to further it's accuracy.  Generally speaking, the more you move in your sleep, the less accurate the readings will be.  But overall, some studies were conducted on sleep trackers, like the Jawbone and others, and it was concluded that they're pretty accurate with sleep tracking.

Also, to this point, no matter what your sleep tracker  says, it cannot accurately tell you about your REM, or deep sleep, stages.  For this, it needs more sophisticated equipment like eye tracker, brain waves, etc...They try to do as accurate a job as they can with movement and heart rate to measure REM sleep but it's not really that accurate.


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

[User]
ELI5: If certain images such as van Gogh's "The Starry Night" are in the public domain, how are reproductions able to be sold?

Do posters pay anything to use an image in the public domain?
How does public domain relate to other types of media like books and audio?

Thanks in advance friends.

[Assistant] Public domain means the opposite of what you're imagining, when something is in public domain it means anyone can freely use it for any purpose (including profit) without needing to pay anyone. Anyone can take a book or movie or song that's in public domain and sell it without needing to pay royalties or fees.


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

[User] ELI5: Why it seems to me that Italian mafia and Yakuza seem to think twice about killing cops and government officials, but other gangs like black gangs or Mexican cartels or Russian mafia would kill them and often brag about it?

[Assistant]
Italian Mafia & Yakuza are effectively businessmen. Yes, they may use violence to enforce their ways, but in the end, they're after money. They don't get what they want by killing policemen & politicians, they get it by *corrupting* them.

Gangs & drug cartels get their money via selling drugs. Cops are *obstacles*, not potential resources.

**tl dr;** Follow the money.


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

[User]
ELI5: When a singer is performing during a concert and they have an earpiece, what are they listening to?

Not sure if this is the best subreddit for this question, but I thought it was appropriate than askreddit.

[Assistant]
It's an in-ear monitor. It helps the singer keep in tune by blocking out external noise and playing back the band audio through the earpiece so the singer can hear themselves in relation to the rest of the band.

Without such monitors, it's actually very difficult for singers to sing in tune because the sound of the band gets drowned out by everyone in the audience and most people can't sing with absolute pitch (i.e. sing the correct frequency/pitch without a reference point).

As an alternative to (or in combination with) in-ear monitors, there often speakers set up on stage that are pointed directly toward the singer/band members that perform a similar function.

In-ear monitors are also sometimes used to secretly provide instructions or other messages to performers.

Edit: It's also worth noting that, in some cases, the audio played back through the in-ear monitor is a pre-recorded version of the song (e.g. from an album). Each band member and/or dancer can then match their live performance to the track played in their ear. This has the added benefit of maintaining consistency (e.g. in tempo and pitch) across performances. This approach also keeps the singer in tune, so long as the band instruments are tuned correctly.


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

[User] ELI5: Why is T.V. static black and white fuzz instead of just a solid color?

[Assistant]
Analog TV signals were originally black-and-white, so both the "snow" and the picture were all black-and-white. When color became available, a color signal was added to the transmission both in the visible picture shown on the screen, and also with a short hidden "burst" of color at the beginning of each line to ensure that the colors are in synchronization and correct.

Color TVs detect this synchronization signal. If it isn't present, the color circuits are turned off by a "color killer" circuit. Otherwise a weak black-and-white transmission would have colored "snow", nicknamed "confetti" in the industry. This would be very distracting and make for unpleasant viewing of black-and-white broadcasts on a color TV.

When you tune to a channel with no signal, random noise is amplified and appears as dots on the screen. Because there is no color sync signal in the random noise, the TV turns off the color circuitry and you see black-and-white "snow". A weak analog color signal will have confetti in color, but if it's just random noise with no signal at all the color circuits are disabled.

Modern digital TV signals use a totally different process and if there's no signal present the TV set itself puts up an error screen or simply goes black.


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

[User] How do ants find even the smallest piece of food far away from their nests?

[Assistant] They send out scouts. The scouts leave a pheromone trail to find their way back. When you see a solitary ant walking over your kitchen work top it's usually a scout and will be running back to the nest to tell all his colony about the crumbs under your toaster.


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

[User]
It seems just about everyone here is on some kind of antidepressant medication and the majority are American - so are Americans more depressed or do doctors in the USA over prescribe antidepressants? Or is the usage similar in other countries?

Does anyone know the statistics for certain drugs for multiple countries - for example medicine "A" has a 1 in 20 person usage rate in UK vs 1 in 11 for the USA?

Are people more likely to be prescribed something in a country with subsidized medicine or without?

[Assistant] "Just about everyone here" Where is "here" for you? It sounds like your question's premise is based on a small sample set based on personal observation. Before your question is addressed, you should be making sure the premise is valid...


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

[User] ELI5: Why was it so important to discover that the DNA is shaped as a double helix?

[Assistant]
it was a clue that each half coded for the other half. DNA is replicated while it is single stranded. Each nucleic acid is matched by its pair and the double strand is reassembled.One strand coded for the other. When pulled apart again they again code for the other side thereby reproducing it almost perfectly.

The helix part is just that there is a twist just as a strand of tape will twist. Any long thin thing will twist, a ribbon, a measuring tape.

The real deal is that one strand will code for the other to ensure replication. The triplet codes specify which amino acid to put in the chain while assembling a protein.


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

[User] In the 80's and 90's all I heard about was Acid Rain. What happened? Did the rain stop pouring acid? Why?

[Assistant]
They put scrubbers on coal fired power plants.

the first google result for "acid rain" is wikipedia; from the middle of the article.

>Overall, the Program's cap and trade program has been successful in achieving its goals. Since the 1990s, SO2 emissions have dropped 40%, and according to the Pacific Research Institute, acid rain levels have dropped 65% since 1976.[20][21] However, this was significantly less successful than conventional regulation in the European Union, which saw a decrease of over 70% in SO2 emissions during the same time period.[22]
In 2007, total SO2 emissions were 8.9 million tons, achieving the program's long term goal ahead of the 2010 statutory deadline.[23]

In other words- 65% reduction in the US, 70% in Europe.


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

[User] ELI5: why do our eyes imprint the outline of images and portray them behind closed eyelids after staring at, say, a window or the sun?

[Assistant] Our eyes don't see in the same way modern cameras do. They have chemicals in them that get consumed when light hits them. These chemicals are constantly being replenished so it is rarely an issue, but when you go from something very bright to darkness, you can see where the chemicals in your retinas are depleted.


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

[User] ELI5: Why have Americans and Canadians "lost" the British accent, and why has Australia "retained" it (in a morphed form)?

[Assistant]
Americans and Canadians didn't lose any accent. Their accent diverged, as did the accents in Britain.

The reason the Australian accent is more similar to modern British accents than American and Canadian ones are is mainly because it was a more recent colony. It wasn't settled en masse until much later.


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

[User]
ELI5: Why do we give prisoners on Death Row a last meal of their choice?

Is this a tradition that we have yet to get rid of? Are there moral or legal reasons behind it? It seems to me that once someone has done something grievous enough to give up their liberty, we shouldn't give them that kind of luxury. Why do we do it?

[Assistant]
The earliest ritual of the last meal was supposed to symbolize the condemned's peace and forgiveness toward the executioner - so that the condemned wouldn't come back and haunt them.

These days, it's mostly to show that we're not COMPLETE savages.


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

[User] ELI5: Why haven't humans developed a simple and clear signal of romantic interest? The vast majority of animals have some form of mating dance/call/thing; why did humans lose/not have this?

[Assistant]
So much of human behaviour and communication is cultural/memetic/linguistic rather than instinctual and deterministic, so instead of a single dance/call/song/thing we have thousands and the meaning depends on cultural context.

On the other hand, we have all kinds of subtle physiological cues to indicate attraction and arousal.  Many of these are conveyed subconsciously, but some people become more skilled at actively identifying them.


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

[User]
How do lungs clean themselves?

I'm mostly interested in understanding the mechanism for this because it's one of the only organs which is directly exposed to the environment. Thank you, in advance.

[Assistant] Most of the larger particles are caught by nasal hairs, then the smaller particles that evade the hair are caught in the mucus produced in the respiratory passages (up till bronchi). Further ahead in the respiratory bronchioles and alveoli (the part where actual gaseous exchange takes place) there are no mucus producing cells, and the even more smaller particles such as bacteria that do manage to reach there are eaten up by alveolar macrophages, which are basically your germ eating cells.


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

[User]
ELI5: If sharks are predators, why are its eyes on the sides of the head?

I read in school that prey have eyes on the sides of the head (sheep, cows, etc) to spot predators coming whereas predators have eyes on the front. Is this rule not applicable to marine biology?

[Assistant] Land predators rely on sight more than sharks do, while sharks rely on smell more. Hammerheads are the best example, their eyes are way out to the side right? They sense the electromagnetic field of their prey, even below the sand.


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

[User]
How does becoming a PhD change your academic life on the day to day basis?

What must you more? What can you do less?

Pros? Cons? What new academic freedoms you acquire after a successful defense? What are newfound drawbacks?

Advice for future postdocs?

I am on my third year our of four and want to make the best of it. I am actually majorly motivated to work on my PhD, but I also want to know what to expect.

Thanks!

[Assistant]
They have to pay you more (but hope you don't know how much they should actually pay you). They expect you to know what you're doing more. You have to get your own permits. You have to find your own funding. You have to motivate yourself to write because you don't have deadlines to meet for someone. You have to fight your own battles (in the literature and in the department).

Other than those (pros and cons as you take them, based on your own situation), not much changes. The science doesn't change, the expertise doesn't change. If you're in a prof position you have to do more busywork (committees, advising, uni service, etc) in addition to the teaching.

Edit: And you can make undergrads call you Dr. You can make other postdocs/profs do it, too, but they'll think you're a douche.


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

[User]
ELI5 Bose-Einstein Condensate

What is it?

[Assistant]
All particles have a property called spin. It is a fundamental property of particles, just like mass. This spin is either integer or half-integer. Particles with integer spin are called Bosons, while particles with half-integer spin are called Fermions. Electrons, protons and neutrons are all Fermions with spin 1/2. Composite systems like atoms can also be either Fermions or Bosons, depending on how many  electrons, protons and neutrons they have.

Fermions and Bosons behave very differently:

Think of the energy levels of a quantum system as a ladder, where each rung represents a different quantum state. If you want to distribute a given number of Fermions on that ladder, then you cannot put more than one Fermion on one rung.  This is the so called Pauli-exclusion principle.

If, on the other hand, you want to distribute Bosons on that ladder then you can put as many Bosons on each rung as you like, since the Pauli-exclusion principle concerns only Fermions.

Now, let's suppose you have some number (say 1000) of Bosons and you have distributed them on the ladder in some way (83 on the first rung, 78 on the second, 63 on the third etc). When you cool the system down enough then something strange will happen: all particles will start to amass on the lowest rung. While the fraction of particles in the lowest rung is at the beginning of the decrease of temperature relatively low, when the temperature goes to zero almost all of your 1000 particles will be in the lowest rung, i.e. lowest state. At T=0, all 1000 particles are in the lowest state.

This process, where Bosons tend to collect themselves in the lowest energy state with decreasing temperature, is called Bose-Einstein *condensation*. It's called *condensation* because it's akin to real condensation: when you cool a gas in a closed box it will condensate on the surfaces, when you cool a gas of Bosons it will condensate into the lowest energy state.


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

[User] ELI5- Why, in the 21st century, do politics still seem to be a matter of opinion? Does mankind simply lack the means to make objective decisions about the running of our nations governments, based on cold hard facts and numbers?

[Assistant]
Politics is about the relative weighting of various interlocking value judgements, and those are rarely if ever possible to sort out in anything like an objective manner.   You can make better or worse arguments about the relative merits of defence spending vs education (or whatever), but only rarely can you objectively define one as better than the other.

So we are stuck with subjectivity here. That's politics.


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

[User] ELI5: If Radio Waves have a lower frequency than visible light, how can radio waves penetrate through surfaces that visible light can't penetrate through?

[Assistant]
Hey! Photovoltaics lab scientist here. Light of any sort (radio, visible, xrays, etc) will keep moving until it interacts with something.

The thing is, light has funny rules for how it interacts with objects. Each object (really, each different type of material) basically has an energy toll that the light must pay in order to interact.

Radio waves, like you say, have much less energy than visible light (lower frequency = lower energy). In fact radio waves have so little energy, they cant afford to pay the energy toll of any material out there.

Cant pay the energy toll? Cant interact. No interaction? Youll never stop. So, radio waves are very good at traveling long distances without being stopped.


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

[User] How come spiders always curl up when they die?

[Assistant] Spiders use hydraulic power to move their extremities, the default position of each leg is curled up, liquid is forced into them to make them move. Once the hydraulic pressure is lost, either from death or any leak in the system, they curl up.


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

[User] ELI5: What is happening when you get a random "itch", and why does "scratching" it give us that weird satisfying feeling?

[Assistant]
Basically an itch is when something very small ie: a dust particle, a dust mite, lands on your skin. When this happens you have very sensitive nerves that trigger that itching feeling so that you remove the intruder. When you scratch two things happen you either remove it and the receptors stop giving you that relief feeling or the scratching makes you feel more pain than the itching sensation so you ignore it. That is why sometimes you scratch it kinda stings and then itches again because the pain was a temporary relief.

Source: a friend of mine is a doctor and we had long talks over the summer over medical things and itching came up, also looked at WebMD to make sure her story was straight.


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

[User]
Are Thymine, Adenine, Guanine, and Cytosine present/used in DNA of all living organisms on earth?

Are there any organisms anywhere that dont use ATCG DNA or a variation of it?

[Assistant] As far as Im aware, all DNA for living things is made from ATCG on Earth. There are viruses and such that use single and double stranded RNA which contains uracil instead of thymine, but those are generally not considered to be living things.


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

[User]
[Portal] if I step through a portal and reach a greater height by only stepping forward, from where did I gain the potential energy to fall?

Using portals, it seems that I could create an infinite energy machine by taking objects to higher ground for almost no energy, and then drop them to gain more energy than I started with and violate conservation. By what mechanism does portal technology conserve the total amount of energy in the system?

[Assistant]
When objects pass through the portals event horizon from an area of low energy to an area of high energy a miniscule amount of energy (in the form of heat) is removed from the surrounding atoms. When you travel the other way the extra energy is dissipated into the surrounding atoms.

This effect propagates at the speed of light and far reaching so it's not observable to the casual user and is difficult to measure for the researchers. Therefore it requires the use of the GLaDOS AI to perform the testing.


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

[User] ELI5: How video game developers make the computer players and how they make them different skill levels.

[Assistant]
A video game is a simulation. You have a list of objects and you update those objects at an interval. Each object has multiple scripts attached to it and each script runs when the game updates. They basically look at what the game is like now and determine where it should be next. A simple example is a moving object. The script in charge of moving the object applies the objects speed and calculates the next position based on the last position

For an AI you write scripts that make decisions based on the current list of objects and update objects accordingly. This can be simple like "get all targets in range, then shoot the closest one". Or you can make it more advanced like "get all targets in range, prioritize based on level, then shoot the closest high priority target".

You can also define states for your AI script to be in; like "searching", "idle", "aggressive" etc. You define what criteria activates one of these states, and then write code to determine the behavior based on the state.

As for difficulty you usually start with the easiest behavior you can program. In a shooter that means enemies have a ton of health, 100% accuracy and always know where you are. In a game like rocket league you just program the car to always point at the ball and drive forward. Then you just work on variations like setting a range that enemies can see you, adding randomness to their accuracy, making them keep a set distance from the player etc.