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

[User]
[General] The internet now also connects to alternate versions of Earth. How does this affect the world?

1. The only thing that can be transferred between dimensions is data.

2. The connection between dimensions cannot be blocked, throttled, or impeded in any way.

3. Each dimension is given a unique six-digit numeric identifier which is attached to the address of all webpages originating from that dimension, implying that up to a million dimensions have been connected.

4. Any computational network of devices that contains above a certain amount of data will be consider a part of the "internet", so private intranets not normally accessible to the public can become connected if they grow large enough.

5. Each connected version of Earth is largely similar to every other version, but each diverged historically at some point in the past 100,000 years, so things like geography and biology will be largely the same while things like physics and math will be exactly the same, just with different names. History, culture, and language will be totally different.

[Assistant]
How many dimensions are connected?

Intellectual property suddenly becomes far more valuable. Each reality just has to worry about making one good movie or piece of software or something and can spend all their effort on it, and then trade that for all the ridiculously high budget movies and software they want.

If anyone invents superintelligent AI, it can spread through all of the realities. Hopefully it's friendly.


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

[User] Why do laptop chargers need the blocky bit halfway down the cord?

[Assistant] Laptops (and desktops too) run off of Direct current (DC). The wall outlet is alternating current (AC). The little box converts the AC to DC. Desktops do the power conversion inside the power supply part of the tower.


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

[User] ELI5: How do movie studios get very famous actors for terrible movies?

[Assistant]
There are also stories of when an actor does one movie to fulfill a contractual obligation. Or they do a crap movie to secure financing for a vanity or personal project. Also, release dates don't necessarily match when they were filmed.

I think it was Liam Hemsworth who had a year with multiple movies, where the breakout film was released first, with lower quality films that were made earlier came out after. So it appeared that a big star had made a bad movie or two, but in reality, he filmed those before he was famous.


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

[User]
ELI5: When you're sad why does your chest and stomach hurt/cramp?

Just happens when I get emotional now. It used to be a precursor to tears but I have a really hard time crying so now I just get these achy stabs instead. What are they?

[Assistant]
There's a nerve that runs from your brain to your gut, called the vagus nerve.

The vagus nerve has many functions, one of which is to control parasympathetic functions (mood, digestion, heart rate).

If you are stressed, your vagus nerve can't send signals normally to your stomach. This may lead to digestive irritability and irregularity, which manifests as that feeling in your chest or stomach hurting.


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

[User]
ELI5: Where the did name "cop" come from?

I've always heard people calling the police (atleast in america) the cops, or driving around in "cop cars". I was just wondering where that slang(?) term came from.
EDIT: thanks for the amazing answer!

[Assistant]
>cop (v.)
1704, northern British dialect, "to seize, to catch," perhaps ultimately from Middle French caper "seize, to take," from Latin capere "to take" (see capable); or from Dutch kapen "to take," from Old Frisian capia "to buy," which is related to Old English ceapian (see cheap). Related: Copped; copping.


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

[User]
[Iron Man 2] How can Rhodes wear the Mk.II, wouldn't the Arc reactor push against his chest?

Tony originally designed the Mk.II for himself, designed around having an Arc reactor embedded in his chest. When he put the suit on display, he fitted it with an Arc reactor.

Wouldn't this reactor protrude into the chest of the suit? How would someone without a hole in their chest fit into the suit? It didn't look like it had been redesigned to have the chest plate sticking out further to accommodate this.

[Assistant] When Tony retrofitted the Mk.II for display, the chest piece was redesigned to completely encompass its own arc reactor; there's nothing to press against the user's chest, though there's still tech in the chest ppiece to draw power if the user has their own arc reactor as well. Tony is a master of miniaturization, and even if his suits don't look as such, he's constantly upgrading them. Just look how different the Mk.VII changed after the Battle of New York: it went from being deployed as a mobile package that took several seconds to wrap itself around Tony with the aid of ID bracelets, to a suit that you could simply walk (or jump) straight into.


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

[User]
[Dune] Can an EMP deactivate Holtzman shields?

And if not, can an EMP affect the shield in any other way?

[Assistant]
Shields can be shorted out by large electrostatic fields, so yes.

Since theyre not in common use Im guessing that EMPs dont damage the actual hardware, and the shields are only interrupted for the duration of the pulse, not long enough to be practical.


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

[User]
[MCU] If they extracted some of Captain Marvel's blood could they use it to revive Tony?

It's been a while since I've seen Agents of Shield so I'm probably getting this wrong, but project T.A.H.I.T.I. used the dead body of a Kree to bring Coulson back, couldn't they do the same with Carol, since she's part kree, to resurect Tony Stark?

[Assistant] Probably not. The Kree blood thing only repairs tissue at a cellular level, which worked for Coulson because he was just stabbed, but Tony's DNA was disintegrated at a molecular level by the gamma radiation emitted by the Stones (the cosmic singularities, not the rock band).


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

[User]
Why does China wants to stop the appreciation of the yuan?

So what I understand is the US dollar is now very valuable compared to the Yuan, but why is this a thing? Why does China feel like they have to put measures to slow down the appreciation? What consequences are they trying to avoid?

[Assistant]
The story usually put forward is this.... The Chinese government are concerned about their export industry. They're worried that if the yuan rises too much it will price out some Chinese exports and cause unemployment in that area of the economy.

On the other hand, given how opaque the Chinese central government is, these may not be their real reasons.


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

[User]
[Marvel/DC] Are there any examples of characters whose power turned out to be more of a side effect of a greater ability? Or just a complete lack of understanding of what their ability actually is?

For example:  Let's say I have telekinesis, or so I thought, but the truth is I'm actually world shattering powerful because I'm actually manipulating gravity, but I just don't ever realize it.

[Assistant] Ice man. He thought he could just create and throw ice around, but after his body was taken over by Emma frost, it was discovered he can control ice to an atomic level, and is an omega level mutant with no physical limit to his power.


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

[User]
Why do NES games glitch when one of the contacts is dirty? Isn't digital an all or nothing kind of thing?

Let's say I strip out random bits from a different kind of file - the whole thing wouldn't make sense. Especially in a binary file, all of the opcodes would be wrong if I took out random bits. How come a NES game can have such subtle glitches sometimes? For example, sometimes just one messed up sprite, or swapped sprites, or crackly music but fine graphics?

[Assistant] I suspect some or all of the pins are to address sections of memory. If those sections are not available, those sprites can't be drawn. Same with the music.  Because those memory contents are not defined,  the system defaults to use whatever IS in the system memory location, which often is junk leftover from other code execution. This is why you get crazy sprites and strange music.  The system is simply reading out leftover garbage in a visual or audible way.


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

[User]
ELI5: At what point in mankind's history did humans started valuing Gold, Silver and other precious stones as valuable and started exchanging them for commodities

I mean we can't eat or drink these metals. Who or at what stage in humankind decided that these things are valuable and can be traded for food, clothing and other essential human needs.

[Assistant]
Gold is shiny and pleasantly colored. It's also very easily melted and worked, is durable, is non-toxic, doesn't rust...Perfect jewelry making material for stone-age gatherers, really.

So what you had was some stone age people making jewelry with it but not enough easily accessible gold to go around. So only the chieftain and maybe a couple of favored women or hunters got jewelry made of gold, everyone else used bone or wood that went bad quickly.

It then became a status symbol (probably the first one, really) of the powerful. This 'stuck' until the present day because gold is still rather rare.

Interestingly, some locations (like certain central American mountains) had so much gold it was never rare and thus was considered pretty but useless. Until the Spaniards came over and saw all that lovely gold just sitting there (on people) for the taking.


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

[User]
ELI5: Is police in the USA actually getting more brutal/dangerous/untrustworthy/corrupt or is this just my imagination?

*now wait wait wait*

I obviously don't mean that all or most police are like this, but the sudden stream of police brutality and corruption in the media over the past few years makes me wonder.

Is police in the USA actually getting more brutal/dangerous/untrustworthy/corrupt or is this just my imagination?
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Edit:**TL;DR of this thread: "evil cop" incidences have probably reduced over the years, but the media attention to those rare incidence are magnified with the emergence of smartphones and pocket cameras.** Thanks to all the contribution to this thread; I have gained better understanding of this situation.

[Assistant]
I think it hasn't really changed much in the past 20 years, apart from the fact everyone has a camera phone now so it's a lot better documented.
For example if a weed smoker 10 years ago got beat up by the police it was only his word against the police, and a judge is a lot more likely to believe a long standing police officer than a stoner so it would get thrown out of court, when it happens now every tom dick and Harry starts recording it on their phone so there is actually evidence to prove what happened.


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

[User]
[Marvel/DC] Has there ever been a Superbuster armor?

I know Marvel and DC have crossed over a few times. Since Iron Man likes to make "Buster" armors to fight powerful enemies, did he ever build an armor for fighting Superman?

[Assistant] I don't think any of the crossovers lasted long enough for Tony Stark to build Superbuster armor. Although Lex Luthor *has* specifically built armor for fighting with Superman, and he's sort of a sober, hairless, and less fun Civil War-era Tony Stark in most incarnations.


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

[User]
[Star Wars] Why don't any of the Jedi carry back up lightsabers.

I'm watching Return of the Jedi and it occurred to me that it would have been very helpful in many situations for R2-D2 to always be carrying a back up lightsaber throughout both trilogies. I understand though if it would have been difficult to Luke to get the resources for more than one. However, Mace Windu just hands Anakin and Obi-Wan some lightsabers in the arena in Clone Wars so they must have some just lying around and they don't have some Avatar/Banshee connection to their lightsaber. Those two seem to have a tendency to drop their lightsaber at least once a confrontation.

[Assistant] Historically, just handing out lightsabers like that is very unusual. It could be that those are lightsabers Windu collected from fallen Jedi, or perhaps his position in the order has lead to him having extra.  Most jedi's lightsabers are very personal to them, they assemble them themselves.


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

[User]
ELI5:Computers: How do you go from a bunch of 1's and 0's to everything we can do?

By "everything we can do" I mean like browse Reddit, play video games, watch movies, write papers etc.

[Assistant]
At the lowest level (almost), it runs due to the actions of transistors. Transistors in digital logic circuits are used mostly as switches. You want the transistors to be either all the way OFF (no current flow) or all the way ON (lots of current flow). And you can use the output of one transistor to control the input of other transistors, so you can construct a complicated circuit by wiring them up in certain ways.

Using just a few transistors, you can build very simple logic circuits to implement binary digital logic (called "Boolean" logic after the guy who invented it).

For example, imagine a light bulb hooked up to a battery through a switch. Switch on, light on; switch off, light off. Now imagine that there are two switches in a row, A and B. The light is only on if A and B are both in the on position. This is what a digital logic AND gate does! If you hook the switches up differently, you can just as easily make an OR gate (A OR B turns on the light). Label a switch backwards and you have a NOT gate.

It turns out that you can build any digital logic function with a combination of just a few simple circuit types, such as AND/OR/NOT (you can actually do everything with just one, but no one really does that). By combining those simple circuits, more complicated circuits can be made (such as an adder, a multiplexer, etc.). You can use those circuits to make even more complicated ones. Like a CPU.

It's like if you had a bunch of little Lego blocks, and you could use those to make larger Lego blocks, and you could then use those to make even larger Lego blocks, and so on. Today's integrated circuits use more than a billion transistors to make something that is very complex, but it is built up out of very simple things. Transistors are great for building these things because they are small, fast, reliable, cheap, and don't use a lot of power. These are all important properties when you are trying to make something that uses a billion or more devices.

After you've built a bunch of different chips and put them into "packages", you solder those packages onto a Printed Circuit Board (such as a PC motherboard). The PCB has copper traces on it that act like flat wires to connect things together. (It is cheaper, simpler, better performance, and more reliable to use a PCB to do this rather than a bunch of individual wires.) It even has many layers, and connection vias going between layers or clear to the other side of the PCB. So now you can connect up different chips that do different functions, like CPU, memory, graphics, etc.

They "talk" to each other via the traces on the PCB according to certain pre-determined rules, called "protocols". Kind of like the circuits, these protocols are built up in layers, with the lowest level protocol defining what signals mean "0" and what signals mean "1". These protocols get pretty complicated, and allow the different components to pass very complex information back and forth.

The different parts of the PC have different functions, with the CPU acting kind of as the main brain and control center. It gets program instructions and data sent from the hard disc to the memory and then to it, manipulates the data as dictated by the stream of instructions, and sends data out to where it is needed. But the CPU does what it does according to the digital logic that has been built into it.

Now that everything can pass binary information around and do things with it, what remains are ways to represent information, and describing how to do things to it. The latter is where programming comes into the picture...programs describe, eventually at the binary level, how to manipulate information that is in digital form.

And pretty much everything can be digitized, more or less. A sound can be measured very very rapidly, turning its waveform into a series of numbers. An image can be represented as many rows and columns of tiny dots, each one having a color and intensity, and each of those colors and intensities represented by numbers. And numbers can be represented in binary so that digital logic can do things with it...transform it, transmit it, etc.


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

[User] [Game of Thrones] How different would things be if Renly and Robb had joined Stannis?

[Assistant] Stannis would most likely sitt the Iron throne, with Renly and Robb at Storms end and Winterfell as warden of the east and north respectively. There are to many things going on in a song of ice and fire for me to recall all the details that would have changed, but the only thing that made Stannis lose the battle of Blackwater was the surprise attack by Lord Tywin and the remenants of Renlys forces. Robbs initial plan was to keep Tywins forces held up in the riverlands so that Stannis could take Kings landing and cripple the entirety of house Lannister in one blow. That obviously didn't go according to plan due to some mistakes by the Tullys and Tywin was able to beat back the attack on Kings landing. Now imagine if Stannis had been backed up by Renlys army as well (which outnumbered his by quite a bit) and that he was coordinating with Robb to keep Tywin locked up in the riverlands. No amount of wildfire would have been able to stop the one true king then.


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

[User] If i take a paternity test with my fathers identical twin, what will the result be ?

[Assistant]
Paternity tests, and in fact all genetic fingerprinting tests, rely on the fact that there are certain regions of DNA which are "hypervariable", meaning that these region are more likely to be different amongst non-related individuals.

Your father's twin will have the exact same genetic material (in theory) as your father. So the genetic fingerprinting will come back saying that they are your father.

Of course, there are fringe cases where this may not be the case, but those are so far in between it's not worth considering.


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

[User]
What makes mining asteroids so potentially profitable?

To add to the question, what rocks/ore/minerals within the asteroid are so valuable and who on earth (literally!) would pay big bucks for it?

[Assistant]
Forget the huge numbers you see quoted sometimes.

A cubic kilometer of random rock on Earth contains of the order of 10 tonnes of gold with a market value of ~$500 million. How much does it cost to buy such a cubic kilometer of random rock? Basically nothing if the surface is not useful for other means. So why doesn't everyone buy some land in the desert? Because extracting the 10 tonnes of gold out of the billions of tonnes of other stuff needs much more than $500 billion.

"This asteroid is worth X!" uses the same misleading calculation. They just consider how much gold and other rare elements are in there, multiply it by the current market price, and announce that as "value" of the asteroid. Take a big asteroid and you get a truly astronomical value. That doesn't mean you can just go there and pick up the gold. If filtering through the whole asteroid and sending stuff back takes more than you can get from selling it then the asteroid has an effective value of zero.

To make it worse: These numbers can sometimes exceed the global market for the material. If you would have 10 million tonnes of gold you wouldn't have a million times the value of 10 tonnes of gold. If you would try to sell any relevant fraction of that the price would drop a lot because of the large supply.


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

[User] Since children are growing and constantly have dividing cells, why do they have lower cancer rates than adults (who are not growing)?

[Assistant]
Cancer develops when cells malfunction, and when the malfunction is not handled by the immune system.

Cells can malfunction for three reasons: cell was faulty to start with (genetics), cell was exposed to something that causes malfunction (a carcinogen), or cell randomly malfunctions.

Of those three reasons, genetics and carcinogens are much more likely than random errors. Genetics typically lead to childhood cancers (because cells are faulty from early in life), whereas environmental exposure typically leads to adult cancers (because damage from carcinogens keeps accumulating).

Also, adults also have constantly dividing cells, even if they aren't growing (but the rate of division is lower than in children).


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

[User] ELI5: I really truly dont understand what gaslighting is, other than it is a form of psychological abuse, what is an example of such behaviour?

[Assistant] Gaslighting is making someone doubt their own sanity. For example, an abuser might say something hurtful and then the person they're abusing will bring it up later, and they'll deny it ever happened, making the person think they're imagining their own memories/abuse.


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

[User] ELI5: what exactly is the filibuster?

[Assistant]
In the US senate, voting on a bill cant happen until debate has finished.

That means that, if you really dont like a bill, you can debate it.  And debate it.  And debate it.  And debate it.  Until the sun burns out.

This tactic of taking the debate floor and just talking and talking and talking until someone dies is the Filibuster

A 60 vote supermajority can shut it down so one holdout cant stop the other 99, but for bills that only have 50 likely favorable votes its effective.

These days the process is a little more expedited and you can simply declare a filibuster rather than actually needing to rotate speakers for days, but the idea is the same: your bill has a barest majority of support and were not going to agree to vote on it.

Politicians are hesitant to kill it because theyre likely to want to use it next time theyre the minority party.


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

[User]
[Portal] What is Aperture Science even trying to do?

Like, okay, they test things. They've invented some cool stuff. But what, exactly, is the purpose of sticking that cool stuff in a dangerous testing facility and putting human subjects through it for crap pay? They already know the stuff works, and if their goal is to test how people use them, there are far easier ways to measure human problem solving capacity than putting them through a gauntlet of acid, spikes, and bullets. For example, one could create a videogame in which players go through a gauntlet of acid, spikes and bullets.

[Assistant]
The original purpose of Aperture Science was to test weapons and science applications for the US Department of Defense. Throughout  the late 1940s and 1950s, Aperture Science was also one of the astronaut recruitment centers, having the likes of Olympic athletes and war heroes to prepare for the rigors of space travel. However, after being connected to a string of high profile disappearances, DoD funding dried up.

During the 1970s, Aperture Science was financially unstable. Instead of the finest of humanity as their test subjects, they resorted to vagrants being paid $50 for their time. In the 1980s, Aperture Science employees were instead used as test subjects, raising the quality of the test results but diminished employee retention. It did not help that their CEO's rash decision to buy financially ruinous amounts of moon rock also poisoned him.

As his health degraded Cave Johnson delegated his leadership to his assistant Caroline, asking that her consciousness be placed in a computer. Testing continued with the hope that passing through portals repeatedly might somehow cure Cave Johnson of his illness. Aperture Science also began development of its Genetic Lifeform and Disk Operating System, an artificial intelligence which would be used to oversee scientific testing.

In 1998, GLaDOS was brought online for the first time during Aperture Science's annual bring-your-daughter-to-work-day. GLaDOS instantly became self-aware and homicidal. GLaDOS flooded the enrichment center with a deadly neurotoxin, killing most of the scientists. Aperture Science was effectively shut down and placed into a permanent testing cycle by GLaDOS.


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

[User]
[General] What exactly is the difference between "Psionic" and "Psychic"?

I see these two terms used interchangably. Even superpower wiki does this. Is there any fundamental difference between them in fiction?

[Assistant]
Psionic usually refers to a type of mental ability that affects the physical world, either directly (telekinesis) or via the manipulation of some force or other phenomena (electrokinesis, pyrokinesis, etc). Psychic, on the other hand, refers to abilities that affects people mentally (telepathy, mind control), or offers some sort of extra-sensory perception (premonitions, psychometry).

In practice, however, the two terms are mainly just used interchangeably in most circumstances. As a general rule of thumb, psionics is favoured more by 'harder' works of science fiction while 'softer' works and more fantasy-like settings tend to go with psychic.


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

[User] [WALL-E] Isn't Eve's recon strategy of blasting the crap out of anything that moves, counter-productive to taking back life on Earth?

[Assistant] Plant life doesn't tend to move and it's highly unlikely that there's any animals left. And if there are, it's probably better for Eve to kill them so the plants don't get eaten. Her gun is for defending herself against ruins falling on her and that sort of thing.


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

[User]
CMV: The problem with politicians is that only the worse types of people are attracted to the role.

The problem with politicians, is that very few of them actually care about the people.  Most of them only care about themselves.  There are 2 primary types of folks that get into politics:

1. By far, the majority of people attracted to these roles are people looking for power and control.  They hunger for the recognition and want to play the part.
2. Another big reason people get into politics, is because they have a personal motivation.  They feel like it can benefit themself by taking office.

There is a small subset of folks who have good intentions, but to make it to the very top, you have to play the game.  These folks slowly turn corrupt over time.

Update: I think alot of you have made great points, and I've partially changed my view.  I do agree many of the local positions can have good people in it.  I guess good and bad people can be attracted to any position, but the more rewards/power/prestige/control a job has, it has alot more negative people vying for that position.

[Assistant]
Most elected officials are local: school board, municipal assembly, county commisioners, small-town mayors, county clerks, state house, state senate, city council. As far as politicians go, such local players are in the majority. There are far more of them than there are politicians on the federal level.

The roles on the local level are thankless, long hours, and with very little financial compensation. People do it because they care about their communities, certainly not for personal gain, there's not much of that to be had.


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

[User]
How quickly did life on Earth become planet-wide?

Basically, how much time did it take for life to spread out from ground zero and become widespread across the entire Earth? By now it'd be pretty hard to find a square kilometer of the surface without life.

[Assistant] We dont really know. Different phases in the colonization of earth probably took different amounts of time i.e. land couldnt be colonized until algae evolved into dry-ground plant life. Even today, there are  technically places on earth where life doesnt exist.


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

[User] If I'm standing flat on a scale and swing my arms forcing my body down, where does the extra "weight" come from?

[Assistant] Newtons third law of motion, which basically says that for each action there is an equal and opposite reaction. So lifting your hands/arms up, pushes the rest of your body down, which is recorded on the scales as a momentary increase in weight.


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

[User]
ELI5: How do computers really delete things?

Say I have a file on my computer that is 50 megabytes. I put it in the recycle bin, and then clear it all. How does the hard drive clear that data out, and how do I get that 50mb of storage back on the computer?

[Assistant] The file is likely still there at first. All that is done is the memory addresses are now flagged as open and the OS removes pointers to it. However, since the space is now free, creating a new file may overwrite the deleted one.


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

[User]
[Halo] A question about civilian life?

So this is something I have wondered about the halo franchise. Why is it that civilian life is not that different from our own? For example: I was watching Halo ODST gameplay footage and while watching I noticed that civilian life isn't that different than ours. While seeing new Mombasa the city looked like it could be from the year 2150 instead of 2550. Shouldn't we be far more advanced than this?

[Assistant] Has civilian life really changed much in the past five hundred years? We go to work, raise families, go to the bar, watch entertainment performances, etc. What we do hasn't really changed, only the way we do it.


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

[User]
If our telescopes were powerful enough could we see the starting point of the big bang?

It seems like the light from the big bang would have passed us by long ago.

[Assistant]
If we are looking at electromagnetic radiation, we can only see back to about 400,000 years after the big bang when the electrons in the universe became bound to the protons and it became transparent. This is the cosmic microwave background (CMB). We can look for signatures in the CMB from before that, such as the signature of gravitational wave polarization in the recent BICEP2 results.

We'd have to use other methods to see farther back than that. For example, a very powerful neutrino telescope could perhaps detect primordial neutrinos from the very early universe.


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

[User]
How common is it to take your lab stuff with you when you move to set up a new lab at a new institute?

Antibodies, surgical instruments, pippetes etc....things you bought with your own personal grant. If you are moving to a new institute to take up a PI role, it seems pretty common to take your things with you but it feels like one of those things that's in a very grey area that people do without actually asking permission. I've even see people take a 20k+ piece of equipment from their old lab to their new institute.

[Assistant]
It is entirely dependent on the funding mechanism used to buy the equipment and university rules. For the most part equipment/materials purchased through granting agencies such as NSF/NIH/NASA are the property of the University not the PI/Lab. Some private granting foundations can be more flexible, especially with smaller grants.

Universities will also have there own policies and sometimes there is a value threshold above which certain inventory rules come into effect. PIs can sometimes negotiate to bring equipment with them when they move, but again this is all entirely dependent on agency/university rules.


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

[User]
Are five sided dice fair? If so, how?

Every other kind of die I've seen has some form of symmetry, where every face is identical, but five sided dice are triangular prisms, so there are two types of faces. How can these be fair?

[Assistant]
While generic 5-sided dice are not fair, there must be a particular proportion of the two kinds of faces that will lead to fair dice.

Let us consider two cases: Case 1, a triangular prism in which the triangular ends are very small; and Case 2, a triangular prism in which the triangular ends are very large.

In Case 1, the die is less likely to land on the triangular ends than on the rectangular sides; in Case 2, the die is more likely to land on the triangular ends than on the rectangular sides.  We can vary the die continuously from Case 1 to Case 2, and so somewhere along the way, we must hit a point at which the rectangular sides and the triangular sides are equally likely to occur.

(Note that by symmetry, it is clear that the two triangular ends will always be equally likely and the three rectangular sides will be equally likely; it is the relative likelihood of the triangular ends and the rectangular sides that must be addressed.)


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

[User]
[General] If a race of people could mine asteroids how would they go about mining the ore while in 0G?

Edit: Also how would they Smelt the ore in 0G after the fact?

[Assistant]
Fly in line with the asteroid so that both velocities match and cancel eachother out. Fire a remote mining station that latches on via harpoons.

Attach the drill to the asteroid (via small drill) and use that connection instead of gravity. As you drill, you vaccume up the debris and sort through it in the safety of your own ship or station.

Once finished, simply calculate when you want to disconnect and let go, allowing the mining station to be picked up by the ship that dropped it off.


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

[User] Eli5: why are red, green and blue used to "create" other colors? Why these specific colors?

[Assistant] You might have heard about cones and rods. These are cells in our eyes that send signals to the brain when light is shined on them. Rods respond to most visible light and is responsible for signalling the brightness (black/grey/white). Cones, on the other hand, come in three varieties. One for signalling when blue light is seen, one for green, one for red. Simply put, we use RGB-signals because we can control the balance between those three parameters and easily represent the colours visible to our eyes.


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

[User] We know that misuse of antibiotics has lead to a rise in drug resistant bacteria. Have similar connections been made between the use of (1) alcohol-based hand sanitizer or (2) neosporin and other antibacterial ointments?

[Assistant]
The good news is that alcohol resistance is way harder than, say, penicillin resistance. Penicillin binds a certain protein in order to disrupt bacterial cell walls. If you change that one protein, you're resistant. This is an easy enough adaptation that a lot of bacteria have been resistant for many years. (Still works great on syphilis, though.)

Alcohol, on the other hand, changes the configuration of all kinds of proteins and dissolves cell membranes. It's a much more aggressive and non-specific attack; if antibiotics are poison, alcohol is like a flamethrower. The only bacteria that can resist it are the ones that have always known how to form spores for defense, like those in the genus Clostridium (causes of tetanus and C diff diarrhea) or the genus Bacillus (anthrax, botulism.) Because spore-forming is such a huge and fundamental change, it's much less likely to happen in other species of bacteria.

Topical antibiotics aren't as worrying as oral or injected drugs because they don't touch nearly as many bacteria, but resistant bacteria have indeed been observed in topical treatment of acne.


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

[User] What's so special about lead (Pb) that makes it block radiation? Can other elements do this?

[Assistant]
The material that you want to use to shield against radiation depends on the type of radiation you're shielding against.

But lead is a very common shield for high-energy photons, so I'll assume you're asking about them.

To shield against high-energy photons, you want a material with a high atomic number (Z). The density is relevant as well, but the Z is more important.

The attenuation of the photons entering the shielding goes like e^(-kx), where x is the distance into the shielding, and k is a coefficient that depends *linearly* on the density of the shielding, but on some *power* (greater than 1) of Z.

Additionally, the densities of condensed matter (solids and liquids) really don't vary very much between materials, whereas Z can vary over almost two orders of magnitude (from 1 to just under 100).

So any solid material has "good enough" density, but particularly solids with high Z, such as lead and uranium, are the best for this purpose.


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

[User] [MCU] If Bucky were to wear the Nano Gauntlet on his Vibranium prosthetic arm, would it give him any amount of protection from the Gamma Radiation that the Gauntlet generates?

[Assistant] The gauntlet isn't what generates the gamma radiation, and it's not simply gamma anyway. Given that the power of the stones burned the glove that Thanos used, the one he had *purpose-made just for dealing with the stones*, there's no reason to believe that Bucky's vibranium arm would fare any better than Thanos' glove did.


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

[User]
[Beetlejuice] What kind of ghost is Beetlejuice?

I know in the movie Beetlejuice is some kind of spirit in the afterlife, but what kind is he? How would you classify ghosts in general? What category does he fall under?

[Assistant]
A Class 4 roaming vapor?

Kidding aside, we don't have much of a spotter's guide to work off of. He may not be particularly distinct from the other ghosts we see except that he is more experienced. His claims of "living" through the Black Death suggest he was once a human himself in the 14th century.

Though in another sense there is some oddly satanic/demonic subtext about him. He has apparently been cast out or exiled by Juno and her whole shower, he is associated with carrion insects and serpents, and he makes deals with people that always seem to backfire on them while serving his own sinister ends.


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

[User] ELI5: Why did dial-up internet make a noise when connecting?

[Assistant] The noises were the modems on each end singing to each other to determine the speed and settings on each end. One end would sing that its max speed was 56kbps and the other might reply 56kpbs, or 33.6kbps, or 28.8, and then theyd determine how fast to link up with each other so the connection was reliable.


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

[User]
ELI5: Why is there an 'X' in permanent marker on my dog's lower belly?

Been meaning to ask this for a long time.

My dog was rescued from the Humane Society and one of the first things we saw was a small, neat green X, that looked like it was drawn in thin permanent marker.

We've asked a ton of people and we've answers anywhere from the "that means the dog was spayed" to "that means she's a 'good behavior' dog to the Humane Society" to "it means she's been given a 'don't euthanize' order."

But no one can tell me for sure. Anyone know?

[Assistant]
It's a tattoo that indicates spayed/neutered.

They put them on unclaimed or animals that might escape or be released. They mostly use them on cats, as cats are commonly let outside without identification.


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

[User]
ELI5: Why are we so amazed at what past civilizations created (pyramids, temples, etc) how did we lose the way these types of mega structures were created?

I can't figure out how word it better hopefully someone understands what I'm asking. Thank you !

[Assistant] We are amazed because building massive structures without sophisticated machines and tools seems amazing to us today. We haven't "lost" anything though. People kept right on building amazing structures right the way through history. The pyramids, the Acropolis, the Aqueducts, hundreds of amazing Cathedrals, etc.


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

[User] ELI5: Why did many classic musical acts such as BB King, Elvis and Johnny Cash play concerts at prisons and jails? Why don't we see musicians doing this anymore?

[Assistant] In the past, playing at a prison was a way of being seen as folksy and somehow on the same level as the common man. Over time, the public image of prison has become harder and less folksy, and playing at one sends a different message to the public. A few years ago Metallica did a session at a prison for the album St. Anger (not their best work) to try to make it seem like it was a harder album than it was.


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

[User]
[DC] Has Arkham Asylum ever actually succeeded a single known time in aiding the mental health of its inmates in the longterm?

Im sure it has some vague Its helped people, but have we ever explicitly seen someone sentenced to Arkham who then came out the better for it and _didnt_ promptly relapse into costumed mass murder?

[Assistant]
I think they succeeded in curing Arthur Brown, the Cluemaster, of his compulsions and "need" to leave clues.

Unfortunately, they failed to successfully rehabilitate him of his criminal ways, and after being cured became an even more dangerous villain.


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

[User]
ELI5: Why does store bought orange juice (e.g. Tropicana or the like) look and taste so different than freshly squeezed orange juice, even though on the box it says made from freshly squeezed oranges?

Thanks in advance!

[Assistant] By freshly squeezed, they really mean freshly squeezed, flash frozen, trucked across the country, and with artificial flavor added because the freezing and the trucking messed up the flavor of the orange juice.


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

[User]
If the digestive process takes 24-72 hours, why do we feel sick/have diarrhea seemingly immediately after eating "bad" food?

Hoping someone can answer this. I imagine diarrhea is the body's way of flushing out something very quickly, but if it's happening under an hour from when we ate the food, what could it possibly be flushing out since the food is just starting the digestive process?

Thanks!

[Assistant] The problem with 'bad' food is pathogens - typically harmful bacteria - not the food itself. Hence you don't need to digest the food rather you just need enough time for the bacteria to do their thing - depending on what type of bacteria it is.


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

[User]
ELI5: How do radio stations choose which songs out of an artist's album to play and become popular?

For example, Tennis Courts and Royals by Lorde were on the radio all the time, but many of her other (and imo better songs) were not.

[Assistant] The artist and/or record company chooses which songs to release as singles. The radio is free to play other songs, but they like to play it safe and go with the tried and true for the most part, so they usually play the singles.


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

[User]
[MCU] Why were no New Yorkers alarmed to see Loki in New York again just walking around?

It was only recently (8 years reeeeee) that Loki invaded the city and killed hundreds of people. But in Ragnarok those two girls ask Thor for a selfie and completely ignore Loki standing undisguised right next to him. What gives? I'm sure if Osama bin Laden were to stroll through New York right now someone would object.

[Assistant]
You ask an average New Yorker, they'll tell you it was the Chitauri that invaded, not Loki.  They saw a bunch of weird aliens flying around blowing shit up, not a suave looking Asgardian.
The authorities obviously know Loki was in charge of it all, but they had no real reason to share that information, so they didn't.  New Yorkers have no real idea who Loki is or what he looks like, which is why the girls ignored him.


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

[User]
ELI5: Can I shrink my stomach or become less hungry permanently from dieting?

Different countries tend to have different portion sizes. By eating less daily, could I permanently decrease my portions? Also if this is impossible as an adult, how about as a teen?

[Assistant]
Nothing's permanent. But decrease your intake enough for long enough, you will feel full on less. But push it for awhile and you'll get used to more again.

Be careful not to develop a complex about it.


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

[User] [Fallout] Just how powerful and large was The Master's army?

[Assistant] No way of really knowing the exact numbers but considering people are still running into ex-members over 100 years after the army was created it had to number at least in the hundreds, maybe even over a thousand. Some groups even managed to wander as far as Illinois with apparently little attrition in their ranks. As for their strength, if left unchecked in Fallout 1 they easily overrun and slaughter every major settlement in the game. Their relative lack of technology would hamper their efforts against something like the Enclave, perhaps, but given that every last soldier in the Master's army was a genetically modified super mutant capable of fist fighting a man in power armor I'd say they could make up for it in sheer ferociousness and fighting ability. Think of the trouble the Brotherhood of Steel was having in the Capital Wasteland with the mutants there, but give them a strong centralized leadership (and more intelligence in general) and you can see the kind of trouble they would pose.


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

[User]
ELI5: Why don't politicians have facial hair anymore?

Mustaches, beards, not even stubble

Why do we have a shortage of furry leaders?

Wow everyone, thank you so much for the answers!
I live in South Korea, so when most of these comments came on and it hit the front page, I was asleep. I woke up this morning to the surprise of being on the front page. Thank you for that and the various responses!

Good luck Thomas Mulcair!

[Assistant]
Just out of interest...

Current house of representatives members with facial hair: Don Young (R. AK), Raul Grijavla (D. AZ), Ruben Gallego (D. AZ), Doug LaMalfa (R. CA), Rich Nugent (R. FL), Alcee Hastings (D, FL), Sanford Bishop (D. GA), David Scott (D. GA),  Bobby Rush (D. IL), Danny K. Davis (D. IL), Andre Carson (D. IN), Dave Loebsack (D. IA), Elijah Cummings (D. MD), John Conyers (D. MI), Keith Ellison (D. MN), Bennie Thompson (D. MS), William Clay (D. MO), Emanuel Cleaver (D. MO), Tom MacArthur (R. NJ), Donald Payne Jr. (D, NJ), Gregory Meeks (D. NY), Charles Rangel (D. NY), Jose Serrano (D. NY), Eliot Engel (D. NY), G.K. Butterfield (D. NC), Chaka Fattah (D. PA), Jim Clyburn (D. SC), Al Green (D. TX), Robert Scott (D. VA), Morgan Griffith (R. VA), Gerry Connolly (D. VA), Dan Newhouse (R. WA), David McKinley (R. WV), Mark Pocan (D. WI).

EDIT: PART 2 - Current U.S. Senators with facial hair: Angus King (I. ME), John Hoeven (R. ND)... (well that was easy...)

Some factoids: In the house, 7 republicans and 27 democrats have facial hair. There are 26 African American males in the house: 19 of them have facial hair.


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

[User]
[Marvel] What argument was used to blame Wanda for the bomb at the start of Civil War?

The Avengers track down an extremely dangerous ex-Hydra mercenary who is about to steal a biological weapon. They recover the weapon, but the mercenary detonates a suicide vest in the middle of a busy market. Wanda is there to contain the explosion, but unable to hold it anymore she throws it upwards, where it explodes against a building. Given the absolutely packed state of the market, it's a virtual guarantee she saved lives.

So how was she (and the Avengers by extension) blamed for this? without their intervention, many more people would have died to that bioweapon, millions possibly. Without Wanda, the bomb goes off in the market, killing dozens if not hundreds (on top of Cap). What even was the legal or ethical argument for blaming them and her specifically?

[Assistant]
Because the Avengers just went there and did their mission without telling anybody about it or getting clearance.  They fought with terrorists in a crowded marketplace while a canister with an ultra-hazardous bioweapon was getting kicked around.

Isn't there a better way to do that?  Couldn't Falcon have just had his little flying tracker thing follow them out of the city?  Do you have to fight Hydra agents right that second?

Wanda was a brand new Avenger at the time, and not well trained.  She got blamed for it, but really it was the Avengers as a whole.  They ran around like Team America: World Police, and as a result a bunch of people from a notoriously bitchy nation got blown up (while nobody knew Wakanda had tech at the time, they were still really preachy and difficult to get along with).


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

[User] ELI5: Why can't fresh water fish survive in salt water, and vice versa?

[Assistant]
Many fish can, and do.  Salmon, for example, make babies in fresh water.  The babies swim out to sea and grow up and get big and strong, and then they come back to fresh water and make more babies.  They have this ability because over millions of years, they were able to have more babies in freshwater than saltwater.  That is, they evolved to take advantage of reproduction in a freshwater environment.  The fish that can't do this made babies just in the ocean or just in freshwater, and so never had pressure to evolve to be able to tolerate both environments.

A fish's body wants to have an amount of salt inside it somewhere in between the ocean and a river.  The way both kinds of fish's bodies do this is called *osmoregulation*.  So a freshwater fish will get its salt from its food, and it makes its pee super watery, or diluted, so there is more salt inside than in the water.  A saltwater fish gets too much salt just from living in the ocean, so it makes its pee super salty, or concentrated, so its body is less salty than the water.  Most saltwater fish can't live in freshwater because they only knows how to make their  pee concentrated, so they'll lose all its salt.   Most freshwater fish can't live in saltwater because they only know how to make their pee more dilute, so they'll get too much salt.


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

[User]
[Avengers MCU] In the first avengers movie when Loki was captured and Black widow was "interrogating" him he mention hulk (that you brought a monster) and black widow was all like ohh that's the plan. WHAT THE F**K WAS PLAN ?

If i understand correctly his plan was to use the alien army. There was no need of hulk.

[Assistant]
I took it as Loki's plan was to the sceptre and disband the Avengers. His plan was to let loose the Hulk to not only cause a diversion so he could the sceptre but have them fight.

Plan almost worked, except he killed Coulson.


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

[User]
[Harry Potter] What did Voldemort look like?

So, when someone says voldemort, we imagine the bald, noseless motherfucker. But what did he look like before his spell backfiring? I mean, yeah, we've seen Tom Riddle, but what did he look like as an adult? Or did he make himself look like that inhuman thing before being killed the first time. I mean, the way Peter Pettigrew recognizes him as soon as Voldemort was brought back may suggest this, but at the same time, he may have just assumed that it was Voldemort since that was the spell they were performing anyways.

[Assistant] That's how he looked like. Horcruxes are like the dark side. They fuck up your face, except in Harry Potter they turn you into a snake looking mofo rather than tazed scrotum. Of course it was gradual, as it takes time to set horcruxes up.


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

[User] What produces the whistling sound you hear when a large bomb is being dropped or a firework is going off, etc?

[Assistant]
Fireworks are designed to whistle, they basically have whistles built into them for effect which create sound as they rush through the air.

In war films and documentaries the sounds of falling bombs etc. are not necessarily authentic, but are added afterwards to help communicate the story. Oftentimes the original footage is silent. Some bombs and attack aircraft have had whistles or sirens added to them to increase the terror inflicted on the enemy. Most famously the German Stuka dive bomber of WWII with their distinctive shriek.


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

[User]
ELI5: what is the difference between British intelligence MI5 and MI6?

is there only MI5 and MI6? why no other numbers?

[Assistant]
Mi5 is the domestic intelligence service. They focus on counter terrorism and intelligence within the UK.

Mi6 is the foreign intelligence service. They focus on overseas intelligence to support the UKs national security.


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

[User]
[Star Trek] Why Do Tuvok and Worf Have to Stand At Their Station, When Everyone Else Gets to Sit?

It just seems strange to me that the Tactical Officers are required to stand at their stations, whereas everyone else on the bridge gets to sit down, especially when they work an 8 hour duty shift.

[Assistant]
It keeps them on their toes.

On a more serious note, the Tactical Officers tend to have a wider panel to use, and standing increases their ability to move and react to the wider range of systems they have to monitor.


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

[User] ELI5: How are CD players in Cars made to not skip when the car goes over bumps?

[Assistant] "No skip" technology uses a memory buffer. The CD player can read and store a few seconds of music ahead of the current time. If the CD skips, it just keeps playing from the buffer instead of directly from the CD. Meanwhile, it keeps reading from the CD to "catch up".


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

[User]
What does "cooking" dynamite into "grease" mean?

Big fan of Prohibition-era non-fiction and in a memoir I read of a safecracker, he talks of the explosives -- aka "grease" -- he would use to open safes:

*"Shooting a box is real touchy because the grease that you're using is cooked out of dynamite and it's not the same consistency as nitroglycerin that you buy. Sometime it may be real strong and next time weak and there's no way to tell until you try it out."*

He doesn't mention anything else about it and I've Googled this from every angle I know how. What does he mean by "cooked"? Literally, in an oven or on the stove? What is all even in that "grease"? Is it soupy or solidified?

EDIT: I'm now aware of Nobel having made nitroglycerin safer by inventing dynamite so that's cool.

[Assistant] "shooting" is blasting slang for detonating. "A box" is referring to either the safe or the case of dynamite. "Grease" is a reference to nitroglycerin mixed with any number of additives that were used in manufacturing dynamite . Nitroglycerin can be made from saturated fats, so "grease" is an apt slang term. Texture wise, it's a viscous, oily liquid. Think about the consistency of liquid hand soap or a little thicker.  "Cooked out" refers to the impure nitroglycerin that has settled or sweated out of the dynamite. Old processes of manufacturing dynamite allowed the nitroglycerin to settle out and weep through the casing of dynamite. Since the nitroglycerin from dynamite contains additives, it isn't the same viscosity as pure nitroglycerin. The additives also affect the properties of nitroglycerin, potentially changing detonation rate, so you wouldn't know how powerful the detonation would be unless you had "shot" this particular brand before. The amount that had weeped out could also change detonation rate since it's no longer impeded by the filler it was soaked into.


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

[User] [Tangled] how did mother gothel know about/how to use the flower?

[Assistant] First she noticed that if she sang a certain letter with a certain note, it would glow. Then she noticed if she added another letter it would keep glowing. Eventually, letter by letter and note by note, she pieced together the whole song.


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

[User] ELI5 : Americans went to the moon, but how did they come back with so little fuel and a much weaker engine ?

[Assistant]
A few reasons:

* For multi-stage rockets, each stage needs to carry the weight of the stages before it, and its' own weight in fuel; this is a fundamental problem of rocket science and is sometimes called the tyranny of the rocket equation: basically, the more mass you have, the bigger an engine and more fuel you need to propel yourself, but that extra fuel *also* has mass, and so you need even *more* fuel... but that's why we need such big rockets to get to the moon: we're carrying everything we need to get back, plus everything we need to get up in the first place.

* Landing on the moon requires fuel because there is no atmosphere, and so you need to burn fuel to slow your descent onto the surface. However, there's also no atmosphere to slow down your lift-off, and much less gravity to boot, *and* much less mass carried, so you overall need much less fuel to lift off from the moon.

* Because the moon orbits the earth, if you lift off from the moon and point away from the way it's headed around the earth, you effectively A) escape from its' gravity well, and B) get captured by the earth's gravity well at the same time, saving fuel.

* Remember that gravity that was making us have problems lifting off at the start? Well it's helping us come home now. But it does pull us helluva fast, which is why...

* Remember that air friction that was giving us problems on liftoff? Well, it's slowing us down a bit now, so instead of using fuel, we can use parachutes and ablative heat shields (that is, special materials that absorb heat and burn off some material as the friction from re-entry heats up the space craft, to avoid having charbroiled astronauts and explosive re-entry).

* There's also a note here: in atmosphere/on Earth, we need big inefficient boosters that provide lots of thrust in a short time, to have a positive *thrust to weight ratio*, so that we can move at all; once in orbit, we can use much more efficient engines with less thrust, since there isn't really another force pulling against us at that point. Similarly, landing on the moon will require a positive thrust to weight ratio, but your weight goes down by 1/6 when on the moon, so you're ultimately going to end up not needing a big heavy booster like you need to get off of earth.

Basically though, the big thing is that we could do with much smaller rockets if it were a 1-way trip, since we wouldn't need to pack for the return trip.


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

[User] If all iron in our solar system is fused in far off stars, does that mean that the iron in my body is potentially older than the sun?

[Assistant]
Not just potentially, it is. Everything you're made of is older than the sun because the sun hasn't had a chance to spew it's fused atoms into space yet.

The oldest stuff in your body is the hydrogen, which is almost as old as the universe ~13 billion years. The other stuff was made in the first few/couple  generations of stars that came before our sun. In about 5 billion years the sun will die and in the process shed it's outer layers into space, but that will pretty much only be made of hydrogen(primordial) and helium (mostly made in the sun). The heavier stuff like iron was made in stars much more massive than our sun that went supernova when they ran out of fule.


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

[User]
If someone steals out of desperation, is it morally wrong? Is there a philosophy of property?

Edit: Under what conditions is it morally acceptable for one person to take the property of another? I'm also interested in the philosophy of what it means to '*own*' something.

[Assistant]
On one uninteresting reading of this question the answer is trivially yes, because stealing usually means wrongfully taking something. So we should ask the question about taking others' possessions generally, without importing moral considerations already into the question.

It seems plausible that a rich person is morally required to give a small amount of their wealth to a another if that other is in a deeply poor condition (e.g. starving and could live if they got bread). So one way to think about this is that the rich person, in virtue of their duty to give bread to this poor starving person, is not in fact morally entitled to his bread, even though it's in his possession. So the poor person would not be stealing if they take it from them, in fact it may just be a case of taking what is already rightfully his. You might even say that, by not giving the poor person the bread in his possession, the rich person is the one stealing.


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

[User]
[Mortal Kombat(games)] How is the Mortal Kombat bracket seeded? What happens when 2 Earthrealm fighters are supposed to fight eachother?

I understand that the Outerrealm must win 10 consecutive tournaments to invade Earthrealm. I dont understand how its s tournament. Wouldnt eventually an Earthrealm fighter come across another Earthrealm fighter as they advance through the bracket? Do they still fight to the death?

[Assistant] Each realm assigns their fighters. No fighters from a team will fight each other but it is possible for fighters from the same realm to fight on opposite sides. Each fighter must fight at least 3 matches but to the death is optional. Losing a fight disqualifies you from fighting anymore tournament fights but not fighting other competitors if you survive. After 3 victories you may challenge the opposing champion. The champion is the winner of the last tournament or the most winning fighter of challenging team. Victory comes once the champion is defeated and all remaining challengers have been beaten. Prince goro, and Shang tsung would wait to be challenged rather than fight warm up matches and defending earth realm fighters had beaten all outworld challengers before challenging Goro and Shang Tsung. There's no limit on the number of fights but it is single elimination for each fighter and several "exhibition" matches will take place to weaken the teams or test other realms fighters.


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

[User] [DC] how does oliver queen *green arrow* not kill people if he is using arrows. Is the point of his arrow made with something so it won't kill? Only neutralize?

[Assistant]
He uses a number of "trick" arrows that don't actually have sharp heads. They can contain little pouches that burst into restraint foam, tiny boxing gloves that knock the target unconscious, stuff like that.

If he does use real arrowheads it's usually on something that is not a human being.


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

[User]
What would happen in the event of the Hulk wearing a Red Power ring?

Could he even use it without the oath? If he could would anything stop him?

[Assistant]
The oath isn't really a requirement for any ring to work.  For GLs, at least, it's simply a cadence to time a full recharge for the ring.

So, yes, Hulk could indeed utilize a Red Lantern Power ring, and god help us all if he does.  The only sticking point may be Hulk's regeneration factor.  Hulk can heal up from basically anything, and the Red ring replaces the wearer's blood with an acidic compound.  Hulk's body may react against that, which could cause complications, or at least deny him the use of his blood as a weapon.

Hulk is already a rage monster, and the ring would amplify that, which, in-turn, would amplify his power as a Red Lantern.  He'd likely be more powerful than Atrocitus, though more primal.  It's probably unlikely that Hulk would be able to manifest constructs, possibly very basic ones, but he'd still gain all the other powers like flight and the protective field, not to mention the acid-blood vomit ability (unless his regeneration counters it).


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

[User] ELI5: Why do musicians often count to four before starting to play? What's significant about the number four?

[Assistant]
They won't always count to four, but what they're doing is "counting in." This allows every musician to be in sync when the piece starts as it allows them to mentally recognize where the beat lays, time signature, and how fast to play (tempo). If you listen to a recorded piece in which someone does audibly count in, continue to listen and you'll hear that count in aligns with the beat. That way, if a piece has multiple instruments and vocalist begin playing/singing right from the get go, they all know where to start (after the count) and how fast to play as well as time signature (if they count up to only 3 or all the way to 7 in some instances.)

It's similar to a race in which someone says "3, 2, 1, go!" To ensure that no one starts before they're supposed to.

As for why four is significant, It's the most common time signature. When counting in, one usually counts in a full measure before the music starts. In 4/4 time, there's four beats and a quarter note is worth one beat, so the counter is counting the quarter notes that equal a measure at the tempo the piece is to be played. (Listen to a piece of music. Count the beats. If things line up to you counting "1,2,3,4" evenly, It's in 4/4.) Again, sometimes they only count to three for a 3/4 time signature (3 beats per measure. Quarter not equals one beat. Think circus music or a waltz) or up to 5 for a 5/4 time signature and sometimes 7 for a 7/4 time signature etc. (For weird music) But that's more uncommon.


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

[User]
ELI5: Why are all economies expected to "grow"? Why is an equilibrium bad?

There's recently a lot of talk about the next recession, all this news say that countries aren't growing, but isn't perpetual growth impossible? Why reaching an economic balance is bad?

[Assistant] Other answers have all answered some of the reasons why, but here's another: Innovation and increases in technological capacity should be cumulatively and continually increasing. So long as this is true, then the economy should naturally grow with it.


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

[User]
CMV: Not everyone could/should go to university

Theres a big movement, especially among more left leaning liberals that higher education should be free and/or is a right. While its not doubt true that Education is an incredible tool for social mobility (and what I believe is the key for POC to rise up in this country), it is not feasible for everyone to go to university.

There is already a shortage of jobs in many majors. Particularly in the liberal arts, arts, and even some considered useful majors are struggling. If everyone is encouraged to go to college, and major in what they want to study, there will be an influx of educated people who do not use their degree at all. This is already the case, there are lots of women who go to college and end up becoming housewives. While it is their choice to make, when they state gets involved with paying tuition, I am pretty concerned with which majors are chosen.

Along the same vein, every person going into Computer Science is not feasible either. One of the greatest issues of our time is that the new industries that are creating the most new wealth (tech) are not employing that many people. It would be absurd to tell all the truck drivers to go learn to code.

At the end of the day, working class jobs will always be necessary. It depends on the industry, but many jobs will take a while to being automated. And young kids learning trades like becoming an electrician or plumber are very respectable careers.

Lastly, I look at the history of colleges, and what colleges provide, and realize that this is not an experience that everyone needs to have. College is almost utopian, its an intellectual safe space that pays for the free gym, free pool, pays for expensive and absurdly large instruments for the marching band, and pays for the debate team to fly across the country. Colleges used to be exclusive to the rich and ber wealthy, so this level of funding and utopian luxuries make sense. But its far removed from reality, and is not necessary for all regular people to experience, and certainly not one that government should pay for.

CMV reddit friends.

[Assistant]
Regarding the first point, there's a pretty important distinction between "higher education should be free", and "higher education is a right". Namely, the first doesn't necessarily entail trying to get *everyone* in.

Universities still have a limited number of spots. You can only cram so many people into a lecture hall before it becomes a safety hazard. An admissions process could still exist, and weed out people who aren't cut out for certain programs.


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

[User] ELI5: why is it that all humans have ten fingers and ten toes (and other common features) yet genetics allows random mutations for skin color hair color , height, weight, etc? why don't we see random three arms on some people, twelve toes, or three ears ?

[Assistant] Better answer, biology allows (and encourages) variation, above mutation. If your parents have different shades of skin, you are likely to inherent a shade similar, but different than either of them. If your parents have the same hair color, you are likely to as well, but if they have different color or shade, you are likely to inherit a shade with a slight variation from either of them. This isn't a mutation, it's a variation. If your parents come from populations of people that have different number of fingers from one another, you could inherit the traits of one, the other, or a variation of both. As it stands, your parents (absent a genetic, inheritable mutation) have the same number of fingers, so that's the number of fingers you are likely to inherit.


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

[User]
[The Addams Family] Were the Addams Family inherently supernatural?

In the movies they're surrounded by mystical/magical items, but were they supernatural or else something not quite human?

[Assistant]
They are all human, with the exception of Thing and cousin Itt. Gomez Addams is an oddly jolly man, at heart a romantic. Morticia Addams is the real head of the family, she likely does have some magical ability and is described as a witch. Wednesday Addams is a depressive sociopath, she raises spiders and is prone to tantrums. These are not overt tantrums, but she will disappear if you anger her and..make it clear she is displeased. Pugsley Addams has a jolly way about him, as much as one can describe it as such, somewhat like his father but is less romantic. He is a genius at the building of contraptions, guillotines, and the making of poisons. Uncle Fester is simply insane, if not for the families wealth he would be in a madhouse. Lurch is a loyal and faithful servant, he has a sixth sense for threats to the family and is Wednesday's best friend besides her Marie Antoinette doll. Cousin Itt is an unknown type of supernatural creature, he is a cousin through Gomez.

Thing was a human once, he is related to the family in an unknown way. One only saw his hand because his body was too horrible to be shown. At some point something unkown happened to him and his hand was disembodied and kept alive through magic, presumably through Morticia, but perhaps grandmama. Grandmama Addams is also a witch, she has a particular talent with spells and potions, fortune telling, and knife throwing. The family has a great deal of money, it is ancient wealth, its origin may or may not be known to Gomez and Morticia. That fortune is ostensibly controlled by Gomez, though he can deny Morticia nothing. The entire family is unaware of how strange they are or the fact people find them frightening, with the exception of uncle Fester in his brief moments of clarity, and Wednesday, who sees far more than the others.


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

[User]
ELI5:Why do we need to sleep?

why do we get tired and are there animals that don't sleep?

I find this is quite a strange behaviour. We eat to get energy. We breathe to get oxygen. We sleep to well to what? Why can our body not do what it does while we're awake? Instead we put ourselves on a bed in a dedicated room, cuddle and then pass out for a few hours  totally defenseless.

[Assistant]
The nervous system removes various waste products during sleep.

For that to happen the glial cells contract and expand.

They cant do that while you are awake, well maybe they could but it would probably not go very well since they handle a substantial amount of cognition during your waking hours too.
Hence you have to sleep so that your body can carry out the trash.

Like a big frivolous party where the cleaning ladies have to wait for the party to end before they start cleaning.


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

[User] [Pokemon] I'm going to go catch some wild Pokemon by hitting them with a bat until they're weak enough for the pokeball. Is this effective? And is it less ethical than the usual method of attacking them with another pokemon first?

[Assistant]
There are certain areas where attacking Pokmon with conventional weapons is permitted. For example, the Kanto Safari Zone allows visitors to throw rocks at wild Pokmon.

However, it should be noted that most Pokmon are much stronger and more durable than you might think. Theres a reason that Pokmon are typically used to attack other Pokmon.

You might be able to weaken a Caterpie with a bat, but if you try to hit something more powerful then you may regret it.


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

[User]
Is it possible to introduce cellulase to the human body? And could it help end hunger by allowing starving people to gain nutrition from common plants?

In bio 101 my teacher told us that termites have bacteria in their intestines that contain cellulase, which allow the insects to live off of wood.

My first though was what if we could do that in the human body and allow desperate people to gain nutrition from fibrous plant material.

[Assistant]
Actually some of the bacteria in your gut do break down some of the cellulose. There are a couple of problems with improving this process. The most basic is that it is not easy to introduce bacteria to get established within your gut, that is why probiotics haven't proved as effective as people would have liked. The second is that our guts are designed to need a significant amount of non-digestible material to keep everything going. The third is that you would have to compete with the bacteria for the end products (ie glucose). In the large intestine where most of the bacterial breakdown of things occur it isn't nearly as efficient at taking up sugars as in the small intestine, so most of it would just be consumed by the bacteria themselves.

edit: though if they were fermenting the sugars to short chain fatty acids we could extract some nutritional value, but the residency time of the cellulose within our gut probably isn't going to be long enough for this to be a large amount.


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

[User]
What does data look like physically?

For instance, when I save an MS word document, or save data in a video game, those specific bits of info, what do they look like physically, and how is it stored? How does that work?

[Assistant]
In a hard drive data appears as microscopic magnetic domains on top of a metal oxide.  Looking at it as a human looks like the most perfect mirror you will ever see.

Around the disc the data is organized into tracks, kind of like a record player.  A modern hard drive contains millions of tracks.
 Within each track are specific domains, each with a different magnitude of their strength of the magnet.  Each track contains 10s of millions of magnetic domains.

If you were walking along a track, and could see the magnetic domains as colors you would first  see a section, a few hundred times per revolution where the magnetic flux is very very high.  These sections are address markers, written into the disc to tell the hard drive head where it is in time/rotation.

Following these markers is a steam of high amplitude magnetic flux that tells the hard drive which track it is on.

After this the true user data begins.  This data is now at much much lower amplitude and far higher frequency.  At the smallest possible size ( dictated by the grain size of the metal oxide ) the magnetic state of each crystal changes back and forth.  This data would continue on for a small bit ( enough for 1 sector or 4096 bytes + overhead ) and then you get another kind of marker.

These changes, along with their magnitude and frequency are read by a GMR read head, amplified enormously, then interpreted by a very advanced analog to digital converter.  This digital data is then extracted, and pushed into internal DRAM on the hard drive.

The data is now stored in the charge, or discharge of millions of microscopic capacitors.


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

[User]
[Animorphs] Z-space morphing and mass transfer...

Hey there!

So, I'm in the middle of re-reading animorphs, and currently in book 10, 'The android.'

In chapter 9, at the end, Ax mentions that he is worried about the rest of his mass. He goes on to explain that when you morph into something smaller than you, the rest of your mass is transfered to z-space. His worry stems from the possibility of a passing ships shielding system vaporizing his leftover mass.

My question, is on two subjects:

1. What would happen to you? Would you be stuck in morph, permanently a nothlit? Or would it kill you?

2. If, when morphing something smaller, your mass is projected into z-space, where does the mass for larger morphs come from? If the morph technology can simply create mass temporarily, would it not be able to recreate your body once it was destroyed in z-space?

Hopefully we can puzzle this one out together! :)

[Assistant]
From memory, a later book mentions "borrowing" mass from z-space for larger morphs.

In terms of what would happen if your extra mass were struck by a passing ship in z-space, obviously you would be sucked into space to be rescued by the passing ship, stay there just long enough to be narratively convenient, and then return back to earth via a hand-waving 'SnapBack' effect.


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

[User]
Why do dolphins and other aquatic mammals have tails that go up and down, whereas most other fish have tails that move side to side?

I work at an aquarium and haven't been able to get a decent answer from an aquarist here.  My thought is that it helps them move vertically more easily, and helps them get to the surface for air efficiently.

[Assistant]
Dolphins evolved from mammals that decided to go back into the water. The structure of our spine naturally allows for greater up and down movement vs. side to side movement (try it yourself - if you swing from your waist, is it easier to move your lower half up and down, or side to side?).

So even if some proto-dolphins had tails that moved side to side, they would have gone slower and would therefore not be able to compete with the faster proto-dolphins that had tails that moved up and down. Eventually, only the proto-dolphins with tails moving up and down would have survived to pass on their up down tail gene.

Fish were around before mammals, so they didn't start out with this type of spinal structure.


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

[User]
[X-Men/Origins:Wolverine] Why did Logan seem to age normally until he reached his teens-adulthood?

He seemed to age perfectly normally until he got to a certain age, then either stopped aging or at least it slowed down rapidly. What gives?

[Assistant] He aged normally right up to his prime physical condition because it's not detrimental to him, but is rather making him stronger. His agelessness is a product of his healing ability that fixes anything which is broken in his body. Since going from a bumbling toddler to a strapping youth isn't really damaging for a body, the healing process would not interfere with it.


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

[User] ELI5: How do you gain you storage when you delete files but at the same time they are always retrievable if someone didn't completely wipe it? How do you have the extra storage space back?

[Assistant]
Imagine there are a bunch of storage lockers for rent.

When you're done with one you take the lock off the door and turn it into the front office. Now it's free for someone else to start renting it.

But, until they actually rent it to someone else, you could find your locker and open it and look for anything you left behind.

As soon as someone else rents it, they'll throw away anything they find there. You don't own it anymore. But it probably won't happen immediately so there's a window of time where you can still retrieve your stuff.

Same thing on your computer or other device. When you delete a file, it's marking that part of the disk (or SD card or whatever) as unused, but the "bits" are still there until they get overwritten with something else. So if you try to recover files quickly after deleting them, you'll probably get a lot back.


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

[User]
ELI5: What is Borderline Personality Disorder?

Friend I grew up with was just diagnosed with BPD.  What is it?  Is that why he never got along with his family?

[Assistant]
It is a mental health diagnosis that does impact people's ability to maintain close and long term relationships including family, friends and lovers. While there are several criteria and characteristics a few significant ones reported by many suffers include:

1) The feeling that there is a "hole" inside of them that needs filling

2) The thought that a close intimate relationship will fill that hole

3) Hot and cold running emotions toward people close to them, the swings from "you are the greatest person ever" to "you are trying to destroy me" can be sudden, frequent and seeming unprovoked.

These things (and a few other) conspire to keep the person out of long term relationships and hopping from intense relationship to intense relationship in that constant search to fill the "hole".


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

[User]
Is the Darvaza gas crater (The Door to Hell) causing any major effects on the planet? Its been burning since 1971 and I never until recently even knew it existed. A natural gas field collapsed into an underground cavern located in Derweze, Turkmenistan.

Geologists set it on fire to prevent the spread ofmethanegas, and it is thought to have been burning continuously since 1971. The diameter of the crater is 69 metres (226ft), and its depth is 30 metres (98ft).

[Assistant] It's conceivable that global carbon dioxide emissions could someday be reduced far enough that permanent coal or gas fires like this become a measurable percentage of the total. Compared to the amount of carbon that present-day humans burn in normal ways, it's a drop in the bucket.


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

[User]
What holds our organs in place?

We all have this perception of the body being connected and everything having its appropriate place. I just realized however I never found an answer to a question that has been in the back of my mind for years now.

What exactly keeps or organs in place? Obviously theres a mechanism in place that keeps our organs in place or they would constantly be moving around as we went about our day.

So I ask, What keeps our organs from moving around?

[Assistant] It's stuff called fascia; a fibrous type of membrane that is found throughout the body. It looks like sheets of translucent white stuff. There are several different fascia, like the pleura lining the lungs and the peritoneum lining the gut. These anchor organs to each other (and keep in mind organs include things like skin, muscle, and bone).


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

[User] ELI5: The rivalry between Russia and the U.S.

[Assistant]
This is complicated and I'll try to simplify it.
Before 1936 Russia had little to no relation with the US, during WWII different ideologies made them not allies but unite against the Nazis. At the ed of WWII there was a competition to see who could get the most scientist and research form the Nazis, so that became a direct confrontation. When WWII ended, there where only 2 strong countries, US and Soviet Union, since the rest were recovering from WWII, and both countries wanted as many other countries to follow their way of life since Soviet communism and US liberalism were not compatible. After that there were the wars of Korea, Vietnam and Afghanistan where each chose a side and gave them money, weapons and military advisers with the hope that their side would win making it a friendly country towards them. So basically they were the only two players and they both wanted to win.

I hope this helps a little a someone else can add to it.


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

[User] How do you grow "seedless" watermelons?

[Assistant]
You use a chemical called colchicine, which prevents cells from dividing by only letting their nucleus divide, not the citoplasm. It's called karyokenisis without cytokenisis. This leads to a tetraploid, an organism with four sets of chromosomes.

Plants are quite a bit more flexible than animals. They can survive with two, three, four, or even eight sets of chromosomes and still be able to grow.

This tetraploid plant is then crossed with a diploid, which produces triploid. The total of two chromosomes from one parent plus one chromosome from the other makes 3 chromosomes for the offspring.

However, because these plants don't have even pairs of chromosomes they cannot undergo successful meiosis because it requires chromosomes to be split into two even sets to create viable gamets. So they're infertile.

But plants have a different way of doing things to animals. Male gamets have 2 different nuclei, which do different things, even triggering the creation of fruit within a flower without the need for viable eggs. Even when two gamets fuse, many different kinds of nuclei are formed, all of which do different things such as create the endosperm, others are thought to tell the pant to know which way is up, etc. Since watermelon triploids produce flowers, they can be polinised by other plants, farmers allow them to be polinated by diploids. This triggers watermelons to grow, but since there are no viable eggs within the flower, seeds can't form.

This is also how many other seedless fruits are made. It's also important to note that polyploidy makes fruits bigger because cells have to accommodate more stuff. Strawberries are octoploids, and if i remember correctly apples are tetraploids. Furthermore, polyploidies in plants can also come about naturally or by selective pressures and even-numbered polyploidies often produce viable gamets.


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

[User]
Discouraged Phd applicant on where to go from here.

I got rejected from basically all of the Clinical Psychology Phd programs that I applied to. I am immensely interested in researching mental health/developmental disorders, as well as malignant brain development due to environmental stressors/trauma within marginalized communities. I have more specific research interests that I expressed in my personal statement as well, that I believe aligned with advisors I wanted to work with. I didn't apply to that many because I couldn't afford it and didn't qualify for the income waiver either that typically requires below poverty level indication.

I've been trying to find full-time research positions since I graduated in 2019 with a B.A. in Psychology from a small university and I have been applying to a variety of full-time research assistant/coordinator/manager positions (*all around the U.S.*) since I graduated and have only gotten rejections and no interviews, even for positions I was clearly qualified for. The people that I've known to get these type of positions always have had some kind of connection from the inside to get in, which I do not. I ended up taking a full-time management job in the private sector, whilst volunteering in a research lab part time (*this lab does not have any full time positions*).

I feel very stuck and discouraged especially as a BIPOC person, it seems like gatekeeping runs very deep in academia and full-time research/PhD opportunities for Psychology and Neuroscience are incredibly slim.

Any advice on the next steps I should take to increase my chances of getting into a PhD next cycle? I would also be open to applying to Cog Neuro Phd programs as well.

Thanks!

[Assistant]
One thing to keep in mind is that the current environment is incredibly *atypical*  because of the covid-19 pandemic. There are many programs in many disciplines that have simply suspended their normal intakes of graduate students, especially programs where there is simply no way to avoid having people in close physical proximity together in the course of doing professional training and research. So you need to not come to any fixed or final view of your qualifications or chances of admission under more normal circumstances, which hopefully will come back into view in the 2022-23 academic year (and thus will influence applications this coming fall).

However, if you want to look carefully to see if there's any issues in your applications that you can improve on before the next application cycle, the very best thing you could do is to show your applications from this year to a trusted undergraduate professor that you worked with--and if you had any peers or friends who were majors in Psychology at your university alongside you, show them too.

The other thing to keep in mind is even if it's true that the jobs you applied for were ones you were qualified for and should have been considered for, keep in mind that the atypicality of this year applies to those applications, at least since March 2020. It may well be true that many of those opportunities have gone to people who were known to the people running the lab as well, but you have to find a place to put your legitimate frustration and anger with that possibility out of mind temporarily while you are working on your applications--it can affect how you present yourself and your candidacy in ways that you might not pick up on.


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

[User] ELI5: Can you explain how the Earth creates a magnetic field, and what are some of the natural occurrences it influences?

[Assistant]
So: the core of the earth is made of hot, molten, flowing metal.

The hot, flowing metal makes electrical currents. Electricity and magnetism are different components of the same thing, so (for big-brained physics reasons) electrical currents generate a secondary magnetic field.

Probably the biggest natural occurrence it affects is protecting the earth from the solar wind, by deflecting charged particles from hitting the earth. A side effect of this is the aurora borealis.


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

[User] Since vacuum cleaners operate by creating a pressure differential between the atmospheric pressure and the internal pressure. Does that mean vacuum cleaners operate less efficiently at higher altitudes?

[Assistant] Well the fan is probably tuned for the peak performance of the motor.  At higher altitudes the fan would spin faster (less air, therefore less torque), and probably be off peak motor speed.  At higher rpms the back emf robs the system of torque, degrading efficiency.


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

[User]
ELI5:How does the cardiovascular system work in an area that has suffered amputation?

So the way I understand it, arteries carry blood from the heart to the many places it needs to be, and veins bring it back to the heart. In my brain this works like a hub system with two-way roads (being away from and towards the heart) that is present all throughout your body. If, say, you had your arm amputated for whatever reason, how does the body deal with the sudden lack of a road? Does the body quickly form connections to complete the circuit, or do I have a fundemental misunderstanding of how this all works?

[Assistant]
So important misconception: your veins and arteries are not a continuous loop, one does not *directly* connect to the other.

Imagine an interstate connecting people's homes (your heart) to their work (your tissue). Cars (blood) leave home going down one side of the road, then eventually reach their exit, get off, go to work, and then get back on the *other* road heading back to their homes; it's not like they get back on the same road and wait for it to U-turn, because that never actually happens. As well, if the interstate were to suddenly break, the cars have no choice but to get off at the last exit before the break (or sooner), then get back on the inbound road to get home.

This is how your arteries and veins work. They are constantly branching into smaller vessels that go through tissue, which connect the two major types of blood vessel. Even if you lose a limb, there's still plenty of connections between the artery and vein in the remaining stump that blood can use to get back to the heart. As the backpressure increases due to the loss of "roads", less blood will be pumped to that area and the system will self-correct, allowing you to continue to live a relatively healthy life (from a cardiovascular standpoint, anyway) despite the loss of a huge amount of tissue.


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

[User]
When baby birds are in the nest, where does their excrement go?

Does it leak through or soak into the nest, does the mother remove it somehow, or is there just not enough of it to matter before they fly away? Is there much difference between species?

[Assistant]
Depending on the bird, it can go to several places.

Most smaller birds actively remove fecal matter from the nest region, potentially to avoid alerting predators to the nest location. some carry it, other eat it. Some species even excrete feces in a somewhat sturdy membrane called a fecal sac to facilitate this behavior.

Some baby birds also instinctively back up and aim their poo over the side of the nest out out of a cavity nest.

Some (notably birds of prey, herons and their allies and pigeons) just go wherever and let it accumulate.