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

[User] [Injustice] How bad do things have to get before Wonder Woman realizes that maybe she made a mistake somewhere down the line?

[Assistant] Probably the moment Clark kills her she may feel a little remorse. She's beaten several villains that were nigh god like, brought world peace, ended so much suffering and pain for others. She willingly fought clark to the death and was willing to lose just to make sure he continued with their goals. It's not love it's not spite or ambition driving her. It's utter devotion to the ideals of the regime. She's spent decades watching politicians and world leaders undo every good deed done by the JLA when the winds change for them. She's seen refugee camps obliterated by militaries she's been unable to stop because of her morality code. The regime has made numerous mistakes and is a tyrannical authoritarian dictatorship but it's accomplished so much for the people that wonder woman has watched suffer that it's a fair trade off in her mind. Even Clark going public executions and murdering shazam wasn't enough to shake her faith in what they're doing. So long as clark stays the course wonder woman will stay beside him.


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

[User]
Why would you scrape a webpage with beautiful soup when Pandas read_html tool is way easier?

I'm learning Python right now, and after getting through a MOOC on the basics, I moved onto another course for Webscraping and I found it challenging and frustrating. The furthest I got was getting the header row for a web table, which was all smooshed into one string. It would have taken some regular expressions to make it usable, so I gave up and went back to a data analysis course. In this course, I've been learning the Pandas package, and it's awesome. All I had to do was take a url and use read_html and it printed a really complete table that was almost ready for analysis. So why was I wasting all that time time trying to use BS to do the same thing Pandas could do in 2 lines of code? What advantages does BS have?

[Assistant] Probably because pandas only works on tables that specifically use <table> html elements, whereas beautiful soup is more general purpose and more finely controlled to search and extract what you want.


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

[User] ELI5: How come when I'm stressed or worried my stomach becomes physically ill and gives me diarrhea?

[Assistant]
When your stress levels are too high, you body goes into fight-or-flight mode. This is where you body redirects energy to the muscles so that you can fight something really well or run away from something really well.

However, in stressful situations you might not actually be able to run away, but your body still redirects energy to the muscles. One of the places that no longer works receives much energy is your digestion system.

Digestion takes a lot of energy to carry out, and we can make ourselves a lot stronger by using that energy to punch/sprint. When digestion stops, your stools will become either very hard or very soft. Diarrhoea is caused by digestion stopping, but fluids in your intestines still moving towards the bowel, which means you poop out a lot of fluids.


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

[User] ELI5: Why do some consider autism to be part of the neurodiversity, instead of a disorder/pathology? What, then, are the implications for other mental disorders? (eg, mood disorders)

[Assistant]
Because in many cases the line between "neurodiversity" and a disorder is a line drawn by society. Consider homosexuality. It was once considered to be a disorder, and is now part of the spectrum of human sexuality. Its removal is due mostly to social activism and protest from, and advocation for, the homosexual communities.

Technically, the only thing that should be a disorder is something that, in some way, results in harm to the individual or others, or otherwise significantly impairs their ability to function in society. But even that has subjective elements. While "harm" is somewhat clear-cut, "ability to function" is not so. Going back to the homosexual example, if you define a person's ability to function in society around a family model - that a person's goal is to find a mate of the opposite sex and produce a family - then you may assess homosexuality as an inability to participate in a significant purpose of society.


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

[User]
[ASoIaF] Why did the dead direwolf get so far south?

In the beginning, Ned and co. find a dead direwolf, and then adopt it's cubs. What was it doing there? It died from a deer antler in the throat, but why did it move so far south?

[Assistant]
Wildlings, giants, other animals and else are fleeing the march of Winter from the north - why not the wolves? Just because they're extinct south of the wall doesn't mean they aren't possible visitors.

This one being pregnant would be seeking warmer and more fertile lands for its cubs.


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

[User]
CMV: Attempted crimes should be treated identically to their completed versions

**I believe that attempted crimes** (attempted murder, attempted rape, attempted kidnapping, etc.) **should not exist, but rather should be charged, prosecuted, and sentenced as their completed versions** (murder, rape, kidnapping, etc.).

Implicit in the very act of an attempt is the intent to commit the crime, and I believe that that is the only thing that should really be considered in a criminal justice system. A person's intent is what informs our knowledge (at least in part) about their willingness to commit the crime, their commitment to actually carrying it out, their remaining danger to the public, and their likelihood for successful rehabilitation. It also implies that the crime was premeditated; there needs to be purpose and intent for there to be an active attempt. Completion of the crime does not inform or imply any of those things in a way that simply a criminal's intent alone does not. Because of that, I don't believe that *succeeding* in the crime should be a relevant factor to the criminal justice system - but I am open to having my view changed on the matter, so **explain why I should CMV, Reddit!** Note that I am in the US and am thinking specifically about the American legal system, but am totally open to examples/points/reasoning/etc. from other countries' legal systems.

*Things that I can already tell you will not change my view:*

* Trying to convince me that this is a pointless discussion because the US criminal justice system is broken/isn't fair/is biased/etc. I agree with that statement as well, but that's not what I want to discuss here, and I think that this discussion is an important part of any other criminal justice reforms we could talk about.
* Any argument specifically related to Trump and/or the current impeachment proceedings. Yes, the whole "well he only *tried* to bribe Ukraine" defense is why this is on my mind so much right now, but for a wide variety of reasons, I don't think that any case study specific to the current president will make a compelling argument as to why my viewpoint is right or wrong *in general,* and I don't want this to be some sort of partisan bickering.

Also, you may intuit that this is part of a broader viewpoint of mine that retribution should have no place in a criminal justice system. I'm certainly willing to discuss (and possibly have my view changed) on that as well, but I wanted to pose this more narrow problem to make the scope of the discussion a little more manageable.

[Assistant]
I agree mostly with this but have one concern.
When guilt or another change of heart causes a person to stop before committing the crime and hands themselves in. This should definitely be treated as a different case for determining punishment as they have already made the realisation its wrong, so the punishment is simply the next step, while someone who gets caught hasnt decided to stop they were stopped so they should be held accountable as if it had happened entirely.


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

[User]
A common symptom of severe radiation exposure is nausea and vomiting shortly after. What biological mechanism is affected by the radiation to result in these symptoms so soon after exposure?

This is a well-known effect of severe exposure to radiation. I've been searching online to find out what specific biological process is disrupted by the radiation to produce this effect, but I haven't found anything.

I can understand the biological origin of the many longer term effects due to tissue damage, like hair falling off and diarrhea, due to the damage of the rapidly reproducing cells. But it is unclear to me why nausea and vomiting would have a much quicker onset (minutes in some severe cases recorded) via the same mechanisms. Is a destruction of the cells in the stomach lining really all there is to it, and we're just more sensitive to it?

What kind of biological mechanisms induce nausea/vomiting, and how are they affected by radiation?

[Assistant]
Vomiting is caused by the rapid death of cells in the lining of the GI tract. The sudden loss of stomach lining causes vomiting.

The reason this occurs is because the cells in the GI tract lining replicate very quickly and have one if the shorter life cycles of any cell type. Cells that have their DNA damaged by radiation, though, cant replicate properly. This process is accelerated by apoptosis of heavily damaged cells. When that happens, the stomach lining degrades quickly, leading to vomiting.

A similar process is responsible for the loss of hair, flaking of skin, and aplastic anemia after acute exposure. Rapidly replicating cells show the effects of DNA damage sooner than cells that replicate slowly.


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

[User]
[Destiny] How many of them are there?!

I'm an average and rather exasperated Guardian and I know for a fact that many of us are busting our asses. The leaders of the Vanguard are telling us all about how crucial our victories are and how much of a difference we are making. Even with all the "progress" we are making every time I'm on patrol I see the same amount of enemies, I have over 16,000 kills by myself not including the Crucible and I'm a typical Hunter. I know they are thousands more of us and many of them are much stronger than I amand have much better records so why the fuck haven't we eradicated the Fallen, Vex, Hive, Cabal and Taken?

[Assistant] You are battling against interstellar forces, and in the case of the Vex, interdimensional ones. The Fallen are likely the least numerous, and probably still number in the tens of millions. For the Hive of the Moon alone, they undoubtedly can call upon billions of Drones.


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

[User] [LOTR books] In the Fellowship of the Ring, the night before entering Moria they fight with a pack of wolfs. But they vanish at dawn and Gandalf mentions that they were not normal wolfs. Why was that?

[Assistant]
They are Wargs - evil wolves of Wilderland. As Gandalf says, they are not simply a hunting pack of normal animals.

There is no explanation given for how they disappeared. Not in LotR, not in Tolkien's private letters, nor in the published draft versions of the story we have in *The History of Middle Earth*.


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

[User] ELI5 - Why when steaming/foaming milk (like for lattes and cappuccinos) does the milk taste sweeter then normal?

[Assistant]
Imagine your mom buys you one of those toys with the different shapes that you have to match to their corresponding shaped holes. Youre excited to start testing your hypothesis that maybe the cylinder one would fit into the star shaped hole but theres one problem. To save money, the manufacturer left all the pieces connected with the extra bits of plastic from the mould and you have to separate them before playtime. Even though youve figured out that the cylinder mostly fits in the round hole, it just wont go in because its connected to the square with that darned piece of plastic.

The shapes are simple sugars you can taste. The holes are your tastebuds. The heat is the scissors your dad will eventually use to separate the pieces

Milk has a sugar in it called lactose. We cant taste it just like we cant taste starch in potatoes but the heat from the steamer breaks down the lactose into simple sugars that are very sweet: glucose and galactose, those fit our taste receptors just right.


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

[User] ELI5: Brexit and what's so bad about it?

[Assistant]
Without getting into the "it's good" or "it's bad" politics of it:

Britain has been a part of the European Union for a long time.  The European Union is an extensive agreement between all its member nations allowing for greatly increased and deregulated international travel, immigration and trade.  Their economies are heavily intertwined - kind of like a couple that has been married a long time and have a lot of joint purchases and accounts together.

Brexit is Britain's recent decision, made by the majority of voters, to leave the European Union.  They now have a few years to sever most of their attachments to the rest of the European Union, like a messy divorce.


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

[User]
ELI5: Why isn't it possible for hackers to downgrade the operating system of iphones?

Fundamentally, a phone is just a little pocket computer. So why can't hackers just wipe everything and install any type of operating system they would like (ie android on an iphone)? How exactly do apple prevent this from being possible? If they can find exploits allowing them to jailbreak the phone, can't they use those to flash other operation systems or older versions of ios?

[Assistant] They absolutely can, there just isn't enough of a demand for many of those types of hacks. For example, OpeniBoot is a project for an open source version of iBoot (the Apple bootloader) that makes it possible to install Android, or many many other OSes, on your Apple device. But because not enough people are interested in doing that, only very few Apple devices are supported because they don't have enough people working to figure out how to make it work on more devices.


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

[User] Why does the Moon's gravity cause tides on earth but the Sun's gravity doesn't?

[Assistant]
The Sun's gravity actually *does* cause tides! They're just weaker than the Moon's tides.

The Sun's gravitational force on the Earth is stronger than the Moon's, but its tides are weaker. This is because tides decrease with distance more quickly than net gravity does.

Tidal forces are caused by the difference in gravity between one side of the planet and the other. Gravity drops off with distance, so one side of the planet gets pulled a bit more than the other. This causes the planet to get stretched a little bit, which is the tidal force.

If you're close to an object, gravity is dropping rapidly, which means that the tidal forces are extra strong. They're strong because the net gravity is strong, but they're extra strong because the gravity is dropping fast with distance. This is what makes tides decrease more rapidly with distance than net gravity, because there are, in a sense, two effects to make it stronger when you're close.

So the Moon ends up dominating our tides, even though we orbit the Sun.


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

[User] if pi = circumference/diameter and if the circumference and diameter are whole numbers, then doesn't pi=p/q? then how is it considered irrational? or is this just an approximation?

[Assistant] If the diameter of a circle is a whole number, the circumference cannot be.  If the circumference of a circle is a whole number, the diameter cannot be. You will never find a circle where both the diameter and the circumference are both whole numbers.


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

[User] ELI5: What is the difference between a military, a paramilitary, a militia, and a private army?

[Assistant]
* Military: In context to the question and in modern parlance, a military nationally funded and controlled fighting force, accountable and fully funded by its national government. The purpose of a standing military is as a defense to external threats. Typically, a standing military does not carry actionable authority within a country's borders.

* Paramilitary: A paramilitary is a militarized police force, often partially funded by semi-local taxes. Unlike a standing military, a paramilitary stands only semi-accountable to its national government, and serves as both an enhanced police force and and as a force against both external and internal threats. A paramilitary carries actionable authority within and outside a country's borders.

* Militia: A militia is a body of volunteer citizens, both organized and unorganized. Militias tend to be self-funded and self-organized. Militias are accountable to civilian law, including local, state and Federal statutes. The militia carries actionable authority within a country's borders, where authority is granted to do so.

* Private Army: A private army is a military force which operates independently of governmental structures, and receives its funding from a private source. The purpose of a private army is to extend force for a person or group of people, and a private army's authority is within the funding and scope of a private interest.


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

[User]
The self in Buddhism

Apologies if this is not the right forum for this question, but could anyone explain how in Buddhism there is a belief of no-self, yet also a belief in reincarnation? What is being reincarnated if there is no self?

[Assistant]
What Buddhism is rejecting is that anything can be regarded as a self.

How is this specifically understood? Most clearly, the problematic conception of selfhood has these qualities: temporal extension (hence the argument from change in the *Antmalakanastra*), agency over the different mental and physical components of a person (hence the argument from control in the *Antmalakanastra*), self-sufficiency (i.e., part of our mental world which *has* our other mental states but isn't itself *had* by anything), and lacking parts (because Buddhists in general are reductionists when it comes to mereological dependence, hence the famous chariot analogy).

But rebirth does not require something of this sort. It merely requires that some aspect of the basis onto which this mistaken concept of self is imputed be continuous between one life and another.

In Buddhism, this aspect is held to be what Bhikkhu Anlayo, in his book *Rebirth in Early Buddhism and Current Research*, calls "the process of being conscious." Basically, what rebirth actually means is that a given continuum of mental events, or "process of being conscious," remains continuous even though the physicality appropriated by it is discontinuous. But this continuum of mental events doesn't have the properties of the problematic conception of selfhood. So there is rebirth without a self.

-

This is why, when Buddhists historically argued with opponents who argued that Buddhism must be false because there is no rebirth (such as followers of the Lokyata school), those opponents didn't say "you're right about selflessness but thus you must reject rebirth." Instead, understanding that Buddhists believe it is *mental continuity* that underlies rebirth, Lokyata thinkers tried to argue that rebirth is impossible because mental properties are caused by arrangements of certain material objects. They argued for this, and then pointed out this means physical discontinuity entails mental discontinuity, since the mental causally depends on the physical, and hence one's continuum of mental events is cut off with the breakup of one's body.


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

[User] [Mary Poppins] What *is* Mary Poppins? A benevolent witch? A guardian angel? A domesticated Fae?

[Assistant]
I think she's a god. As in the New American Gods, where they are formed from a combination of belief and ritual. Mary Poppins is British. Like, *literally* the god of British. The rituals are cleanliness, respect, tea, and a reserved but sincere form of fun.

She is basically the result of the collective consciousness of "Britishness" given humanoid form.


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

[User]
[General] Will a genie grant wishes through a third party?

Let's say I can't use a genie, like I already got my 3 wishes and want more. Can I just grab a random person, put a gun to their head, and force them to ask for wishes on my behalf? Is there anything a genie can do to refuse wishes made under duress?

[Assistant]
I think the answer is yes, the genie would grant the wishes, *but* your plan wouldn't really work if the random person has even a modicum of sense about them. They just have to use their first wish to eliminate whatever threat you're making, and then they've got two more wishes.

I think the better business model here isn't to force people to make wishes under threat of harm. Instead, you *sell* people wishes. You'll let them use the lamp for whatever they want at the cost of one of their wishes. They get two wishes, but they have to use their third one for whatever you tell them.


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

[User]
How can BBC, Sky, Channel 4 etc. show programmes and ads on my TV but say their content isn't available in my region when I try to view it on their respective web players?

To clarify: I live in Ireland. These are British TV networks.

Ive heard similar situations of people in Canada having American networks on their TV and are told that the content also isn't available to their region. What is the reasoning behind this? Is it a smart move in terms of business and ad revenue ?

Thanks.

[Assistant]
It's worth pointing out that the BBC doesn't show ads.

As for the other channels, it's a licensing issue. They pay for programmes to be shown at a certain time, and then to be hosted online to be available for X amount of time. For example, BBC3 shows Family Guy late at night, but is **not** allowed to put it on iPlayer.

Hope this helps a little.


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

[User]
[Fullmetal Alchemist] [spoilers] Could Ed learn alkahestry?

At the end of the manga/Brotherhood, Ed gives up his ability to use alchemy. Does this prevent him from using alkahestry as well, or could he theoretically learn it?

[Assistant]
Alkahestry differs from alchemy in that they use different power sources, the former 'the chi flowing trough the earth' ^((whatever that is supposed to mean)^) and the latter the tectonic shift as well as the power of the Homunkulus' philosophers stone.

They still get channeled the same way, through the gate of the respective practitioner, and so Ed probably can not do it.


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

[User]
What does mean sea level mean if you're thousands of miles from the sea?

As I understand it, Mean Sea Level is defined by taking the time-averaged effective gravitational potential of the water-air boundary averaged over the world's oceans. Since sea levels are rising globally, we choose some datum and stick to that. This seems reasonably unambiguous.

If the summit of Everest is 8848m above MSL, does that mean it's 8848m directly above a point within the crust on that same equipotential, or does it mean it's on the equipotential defined by the average of all points 8848m directly above the sea? Or does it mean something else?

How much difference would there be?

*To rephrase the question: if you hollowed out Everest and made tunnels (sealed against groundwater) connecting that cavity to the oceans, would the water find a time-averaged level 8848m directly below the summit?*

[Assistant] Sea level is affected by gravity/mass (hence the moon causing tides and so on...). Therefore mountains affect the sea level. Currently, sea level is calculated by assuming the entire earth is covered in water, but the mass from the mountains is still there (hard to imagine, i know). Then the water "bulges" in some places where there is a lot of mass (also tectonic plates and such play a role), in these places sea level is "higher". To answer your rephrased question: yes (assuming that the tunnels do not measurably change the mass of Mt. Everest).


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

[User]
ELI5: Why do pirates use strippers to get 4k content?

 Why do pirates use strippers to get 4k content of streaming websites? Why don't they just get a 4k screen capture service and record the screen while playing the video?

[Assistant]
If you merely capture screen, you will only get pixel by pixel data. Saving pixel by pixel one hour of 4k video would take tremendous space

4k denotes 3840*2160. That is the number of pixels on screen on a single frame, or in other words, that's 8 million pixels per frame. Each pixel should have color information tagged on it as well, and usually you have 16 or 24 bits to denote color of a single pixel. So that's at least 120 million bits per frame. At 60fps, each second has 60 frames, bringing us to 7 billion bits per second, or 21000 billion bits per hour. That would be equivalent of 3000 billion bytes or 3 terabytes.

3 terabytes for a hour-long video is quite a lot.

How this works is that videos are actually highly compressed. Compression algorithms however lose information(unless you deal with lossless algorithms, but those are significantly less effective at reducing size down from that 3 terabytes). If you capture 3 terabytes of video, you then need to start deciding where to trim it down, and how to have something of usable size to produce end result similar to the video you captured.

But the 4k video you were watching was already compressed, and if you could just tap into that, you would directly have usable video file of very small size, and you wouldn't lose any video data on re-compression.


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

[User]
CMV: I believe people who volunteer for admin/moderator positions are power hungry and get satisfaction in controlling other people.

CMV: People who volunteer in admin/mod roles in an organization are power hungry and like having power over others.

The statement is obviously not true for everyone, but I find that a good number of people who volunteer for these positions (and sometimes the paid ones too) just get off on having power over others no matter how small or inconsequential.

Examples: Home owners association admins who drive around looking for homes to scrutinize even when its a small infraction; server moderators who threaten removal of content or removal from the server when someone doesnt respect them to the degree they want; and channel moderators who screen everything to such a minute level that they end up hindering free speech.

I find it pathetic and a good sense of character when the power is abused.

I was just recently threatened to be banned on a different subreddit, because I questioned a decision they madeone they made with little evidence to back it up.

Change my view.

[Assistant] Moderation is something you only notice when it's done badly, either because its obnoxiously strict or because a forum is a disaster because it isn't being moderated at all. You never notice the moderators who are keeping things reasonable and dealing with all the unreasonable people who want to cause trouble.


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

[User]
[ELI5] Why does aperture size effect depth of field?

Why does a wide aperture blur the background while a narrow one keeps it in focus?

[Assistant]
Imagine a light ray emitted/reflected from a specific single point on an object. If your aperture is infinitely small, there's only one position that ray can ever end up after going through the aperture. Do this for all rays emitted from said object, and since there's only one place for each ray to end up, which is related to where it was emitted from, you get an exact replica of the observed object.

If your aperture is bigger however, you could have two rays coming off the same single point on an object, leaving at slightly different angles yet still going through the aperture. Since that single point somehow gets represented in two places after passing through the aperture, blur happens.


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

[User] ELI5: why do the effects in older movies (some not even 10 years old yet) seem so cheesy now yet back when the movie was released it seem so real!

[Assistant]
When we haven't experienced something that much, we pay less attention to the details.

If we ate bacon for the first time, we'd get blown away by the taste no matter how it was cooked or where it's from - it's unique, delicious and memorable. After eating it every day for a month, we might develop a preference for how it's cooked (less crispy etc). After eating it for a year, we might start to prefer specific cuts of bacon or bacon from specific farms etc.

Movie effects that are 'groundbreaking' at the time won't hold up later because we'll have seen it over and over again in other movies since and we will notice the flaws that couldn't be noticed before.

Also, if you watched that effect originally as a kid, you've experienced a lot more life in general and you're more likely to scrutitise what you see in any context.


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

[User]
ELI5: The difference between AMD and Intel?

Thankyou all so much!!

[Assistant]
For the most part, you can think of them like competitors in any other market -- e.g. Honda and Toyota.

Both car manufacturers make cars -- some that are super gas efficient, some that can hold a lot of people, and some that are sporty.  One company might develop some cool new technology, and the same with the other.  At the end of the day though, they still make cars that travel down the same roads and use the same basic principles (e.g. gas engines, four wheels, etc).

Well AMD and Intel are similar in that regard.  At the end of the day, in order to be able to use their chips in a computer, they have to be able to do a certain specified set of things.  How they accomplish it can vary as long as at the end of the day they get to the same result.


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

[User] ELI5: How do people measure statistics of things like what state has the most human trafficking?

[Assistant] Very hard. In general, data on this and similar issues comes from multiple sources, some of which include official crime statistics countries report to various international organizations such as Europol, Interpol, UNOCD etc. Depending on the editor/user of data, some will be evaluated and supplemented by other sources - for example drug exports from and drug imports into etc/arrest statistics/cross border data for immigration offenses and others.


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

[User] If one recovers from COVID 19, does the body become immune to the virus? Or is there a possibility of contracting the disease again?

[Assistant] From an interview with Dr. Fauci he says that with it having low mutation rate it's unlikely to become reinfected with another strain, and although they haven't confirmed or ruled out anything it's most likely we develop an immunity to this virus after contracting it. So unless thing's are really crazy with this virus, we will have immune memory cells for it as normal.


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

[User] ELI5: Why does the same water feel a different temperature to your body than it does to your head? For example when in the shower?

[Assistant]
Fun fact: you cant actually sense temperature; not in the way we usually think of it.

Instead, you sense the transfer of heat into or out of your skin. If different parts of your body are different temperatures, they will feel the same temperature differently.

There are a couple of experiments you can run to illustrate this:

1. Get three bowls of water, big enough to stick your hands into. Fill one with icy-cold water, one with hot water, and one with luke-warm water. Put one hand in the cold water and one in the hot water, and hold them there for a minute or so. Then put both hands in the medium water at the same time, and notice how each hand reports the temperature of that water differently.

2. Leave a block of wood, a piece of metal, and a plastic object in a room for a while, so they end up being the same temperature. When you feel them, they will feel different temperatures, because the different materials transfer heat more or less efficiently.


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

[User]
Does your body still "recharge" at all if you are just lying there, eyes closed, not moving, but not sleeping?

Wondering because I've heard that if you are trying to nap, but can't really fall asleep, you're still benefitting. Would love to know the actual science behind this, if it exists.

[Assistant]
Yes, to a certain extent.

The body's systems are not usually just "on" or "off". There are gradients and different levels of activation of each system in the body. Even within the context of sleep, there are different kinds of sleep, with some biological processes occurring at different rates.

Several of your body's recovery mechanisms are always active. They are constantly fighting against the damage inflicted on your body over time. Resting just reduces the damage being inflicted, causing the effect of the recovery mechanism to be more pronounced. Other mechanisms will increase or decrease based on your activity level.

There are some mechanisms that kick in only when you're actually asleep, so resting is never going to be "enough", but you definitely get some benefit.


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

[User] Why do mRNA vaccines use mRNA in order for the body to create the covid spike protein? Why can't we just create the spike protein and make a vaccine using that (eliminating the intermediate step)?

[Assistant] Since a single copy of mRNA produce many copies of the spike protein, its easier and more efficient to have your body produce the spike protein without having to worry about stability of the spike protein in solution, the spike protein forming aggregates, etc. its just much cleaner to inject the stabilized mRNA and let your body take care of the rest.


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

[User]
How are plants and animals thriving in Chernobyl?

My understanding is that humans won't survive long, especially if they eat things from the ground. Why are the wolves, moose, bison, birds, trees, grass, and bushes fine?

[Assistant] Because radiation isn't some super-lethal force that destroys all life.   We are constantly exposed to radiation from the ground, air, and space.  It turns out humans are far more lethal to plants and animals than the radiation levels within the exclusion zone.  So in the absence of humans, wildlife is thriving.


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

[User]
ELI5: Why is thigh skin so much thinner than skin on other parts of the body?

I was looking up why thigh chafing happens so often, and apparently one reason is that thigh skin is so much thinner than skin on other parts of the body. Why is this?

[Assistant] Most people in our evolutionary past were normal weight or underweight and for them this was probably never really an issue (especially when you consider that they didnt have clothing (or at least not shorts and trousers) for most of that time). So having thick, robust skin on the inside of your thighs was probably never selected for.


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

[User]
[Undergrad] Allowed acquaintance to base her homework off mine, got accused of plagiarism.

**Background:**

I'm a 3rd year computer science student in Canada, taking a Theory of Computation course. I've been accused of plagiarism.

**What happened:**

A month ago we had an assignment due into which I put a lot of effort. After I had finished, an acquaintance of mine asked me for help at the last minute before the due date, so we went to the library and she looked over my copy, and asked me questions from time to time. I never looked at her answers, but she acted as though she changed hers sufficiently.

This is the kind of class where answers end up pretty diverse, so the TA grading the assignment realised all of her answers were similar to mine and accused us both of plagiarism. No formal action has been taken yet.

**Now:**

On the recommendation of my friend, I plan on going to the school law clinic to get advice, but I'd also like yours. How can I get out of this mess without a notice of plagiarism on my permanent record? If at all possible, how can I not receive a zero on this assignment that I worked so hard on?

Thanks in advance for any responses!

[Assistant] So, based on the details in the post, it sounds like your classmate is guilty of plagiarism (passing off someone else's work as their own), but you're guilty of _academic dishonesty_ (of which plagiarism is one form), since you facilitated your classmate's plagiarism/dishonest submission of work.


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

[User]
[Dragon Ball Z] Why didnt Cell ever use the Kaioken when he was losing a fight?

He should be able to, more than Goku even, because of how durable his body is and how he never runs out of energy. If he did that, he would have won damn near every fight he was in.

[Assistant]
Does cell know about kaioken?

If he does, it may be a technique that requires proper training under a teacher compared to something like the kamehameha, which seems be learnable by seeing it in person.


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

[User] ELI5: How does pool cleaning work? Surely, even if dissolved, all that crap is STILL in the SAME water?

[Assistant] It depends. A lot of the material settles out of the water and collects on the bottom or floats to the top where it can be removed mechanically. Some of it do end up in the filters in front of the circulation pumps for the pool which can then be cleaned out. However some of the algae will dissolve into smaller molecules that dissolves in the water. And yes, the crap is still there just in the form of various protein, sugars and fat dissolved in the water. Eventually though they break down into simpler molecules like carbon dioxide, nitrates, salts and water. Some of these do leave the pool in the form of gas. But the rest is pretty harmless.


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

[User] Humans see in color, pigeons see millions of hues, dogs see in black and white, snakes can sense heat, and flies have millions of lenses in which they perceive the world. How then, do we know what the world actually looks like?

[Assistant] It doesn't "actually" look like anything. "Looking like" is something the world does in various ways to things that perceive things visually. There's no "actual" version of it that isn't relative to things doing the perceiving.


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

[User]
ELI5: Why are there so many planes crashed in the Rocky Mountains, East of the Continental Divide?

I'm curious about the science of why the altitude or this specific area was so difficult as well as the social/political/whatever climate that made this happen.

[Assistant]
Pilot here with mountain-flying experience, I'll try to answer the question as completely as possible without getting to science-y.

There are a two main reasons why this happens:

* **Altitude**: In the same way that your car produces significantly less power at higher elevations, small aircraft produce less power at higher altitudes (this is because the engines of both require oxygen to create power, and there is less oxygen at higher altitudes).  If pilots aren't trained or prepared to handle the (significant) lack of power in the mountains, they can easily get themselves into trouble by selecting a too-short runway, flying into a valley they can't climb out of, etc.  This also explains why airplanes don't just fly higher: small aircraft generally don't have enough power to fly much higher than 10,000 feet.

* **Winds**: Mountain winds are typically strong, and strong winds are always a challenge for small planes close to the ground.  But the real problem with mountain winds is that they often contain *downdrafts*, which are wind drafts that do exactly what they sound like: travel downwards, not just side-to-side.  These downdrafts can easily overpower a small airplane (which is already underpowered enough), and it is nothing new to hear about a small airplane that wars literally sucked down into the side of a mountain by a downdraft.  Because the east side of the Rockies is the lee side (which means that the wind generally travels from west to east), downdrafts are particularly abundant there.

I'll be happy to go into more detail if you'd like.


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

[User] [LOTR] Is there a biological reason Boromir was able to fight despite having three arrows in his chest? Or was it just a matter of push-ups, sit-ups, and plenty of juice?

[Assistant] Arrows are only super lethal when they strike the heart or brain. Anything else is death by bloodloss or internal injuries which takes longer. Boromir is full up on adrenaline and righteous fury so he's ignoring the pain and pushing through until shock and death set it.


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

[User] ELI5: Why do redheads have a different reaction to anesthesia?

[Assistant]
Scientists are actually a little unsure. But in redheads there is a mutation in the gene that governs the release of melanin  which causes tans and darkens hair. Broken gene means no melanin and you get light skin and red hair.

By sheer evolutionary coincidence this same gene is also reused in pain reception. There's lots of genes that have multiple functions like this.

So basically the pain signals are harder to shut down and pain related nerves are a bit overactive. End result is anasthesia doesn't work as well (by about 20%) and redheads can be more sensitive to pain.


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

[User]
[Pacific Rim]Why do the people building the wall (the one that was meant to keep the Kaiju out) have such bad working conditions?

New York Garbage men have really good salaries because the city would basically be drowning in rubbish within days  if they were ever to go on Strike. I'd have thought the wall builders would have similar collective bargaining power, because if they ever decide to just stop working it'd mean there'd be vast areas of the coast that'd be left unfortified?

[Assistant]
You say that like they're unionized and non-replaceable.

With Earth's economy bent towards defense and civilian populations fleeing coastal cities, there would be *lots* of people willing to do manual labor for little pay. Anyone that *doesn't* want to work is told to piss off. We see a little of that in the first film.


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

[User]
If cardiovascular exercise is healthy for you because it gets your heart pumping, why wouldn't it be considered a "healthy" side affect of certain legal/illegal drugs the fact that they get your heart pumping (ie. cocaine, coffee, etc.)?

I know drugs legal/illegal, although sometimes fun, are not "good" for you. But an important part of cardiovascular activity is raising the heart rate and making that muscle work more actively then when it as rest. So why wouldn't whatever drug that might make your heart pump faster have some kind of "good" side effect in that it makes the muscle work harder than when it is at normal rest rate.

I'm not wondering this to at all make a justification of drugs being good for you in some way. Just a small thought I had earlier today.

[Assistant]
Increased heart rate due to exercise is caused by muscle tissue needing more oxygen. The heart pumps harder to
send more oxygenated blood to the muscles. This increased pumping strengthens the heart muscle, which is good for heart health. Increased heart rate from chemicals like caffeine, nicotene, amphetamine, etc. is caused by vasoconstriction--the constriction of blood vessels. This causes the heart to have to pump faster in order to pump the same amount of blood, and in the long-term can cause hypertension.


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

[User]
[Breaking Bad] What would have happen if Hank didnt notice the book?

In season 5, Hank figures out that Walt was Heisenburg after finding the book Gayle gave him

If Hank didnt go into the washroom that day (or maybe if Walt didnt put the book in an easy spot to find), what would happen to Walt?

[Assistant]
Two possible answers:

1. He gets out of the game and continues to launder money through the car wash and/or other means. Heisenburg was only valuable because he knew the formula to cook the meth. By the time he was trying to get out he had around $80 million in cash in the storage locker which, as Skyler points out, is more than they could ever use. He either sells or gives away the formula (eg. posting it on the dark web) to make his own knowledge of it worthless to prevent kidnapping, etc.

2. He tries answer one but the lure of being Heisenburg becomes too great and he continues to try to be a drug kingpin which either ends in his death or arrest. Walt was given more than one chance to give up the drug game and couldn't do it because of his pride.


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

[User] ELI5: Why can drinking too much alcohol cause you to go blind and what is the biology/chemistry behind it? Is it specifically because you absorb too much too quickly (like with moonshine/liquor/spirits), or is there something else that causes it?

[Assistant] Drinkable alcohol is ethanol; it's what in the beer and spirits you buy at your liquor store. Moonshine that isn't distilled correctly builds methanol which the body metabolizes into formaldehyte (which is toxic) and then further into formic acid which will harm your nervous system, beginning with the eyes (causing blindness).


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

[User]
[Star Wars] How does anyone understand what the hell R2-D2 is saying?

I mean its just beeps and boops yet people seem to know what he is saying especially in the animated Star Wars the Clone wars. Anyone know whats going on?

[Assistant]
The only time you see anyone interact directly with his speech in conversation form, they either have a digital display translating (Naboo fighter, X-Wing fighter) or C-3PO is translating.

Think of R2-D2 as a dog. A *really smart* dog.  No one, aside from C-3PO and other droids, really *know* what he's "saying", but they can guess based on the context of the situation.

"Boy, we sure are lost."
*Woof*
"Maybe we should go that way."
*Whine*
"Haha, okay, we'll just turn around instead."

Replace the woof and whine with beeps and whistles and it's basically the same as interacting with R2. Luke may have an advantage in understanding R2 since he's been around astromech droids his entire life.


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

[User]
How do the energy economies of deciduous and coniferous trees different?

Deciduous trees shed and have to grow back their leaves every year but they aren't always out-competed by conifers in many latitudes where both grow.  How much energy does it take a tree to re-grow its leaves?  Does a pine continue to accumulate energy over the winter or is it limited by water availability?  What does a tree's energy budget look like, overall?

[Assistant]
Energy required to grow leaves is only part of the equation. Conifer and deciduous trees have different strategies to survive which all depend on the balance of energy, nutrients, and water.

Conifers (in general) are better at conserving nutrients and water bc not only do they keep their needles year round but they also have a waxy cuticle that doesnt lose as much water or nutrients and have different internal structures which more efficiently retain water (tracheids). So overall conifers require less nutrients and water to grow and produce less energy bc of the small surface area of the needles. But they can photosynthesize year round. Hence why you usually see more conifers in colder or harsher growing areas.

Deciduous trees take a different approach. They make a lot of energy quickly through the high surface area leaves. But this comes with drawbacks. They usually require more nutrients and water because they lose much through their leaves (stomas) and from dropping leaves. When growing conditions change in winter they shed their leaves to keep from losing too much and repeat the cycle again. This is why you usually see deciduous trees in more favorable growing conditions. Such as warmer climates or close to streams in harsher climates.

Simply put conifers grow slow but are always making energy while deciduous grow fast as possible in the short amount of time they can then take a break. This is kind of a broad characterization of both but gets to some of the main differences. There are many examples which dont fit this exact paradigm.


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

[User]
If Greece withdraws from the Euro and immediately has to introduce the Drachma, how would they determine the value?

Taking a common economics example - The banks close, the new currency is taking over the day after, so a general store need to switch currency. How does the shopkeeper know how much to price up a Mars Bar for?

I appreciate that the price it is introduced at is *very* unlikely to be the price it is at the end of that day as the markets will dictate the true value, but they have to *start* with something.

Other questions here seem to be more about the process of changing currency, whereas I'm concerned with the immediate setting of that currency rate.

[Assistant] I think they would immediately set it at one drachma = one Euro--so that shopkeepers would not need to reprice anything and bank accounts would have the same numbers--but this value would probably rapidly decline.


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

[User]
ELI5: Could a human brain retain consciousness without a body, assuming it was still receiving adequate oxygen/blood flow?

So basically, if you could supply the brain with enough nutrients, oxygen, blood, etc., through an artificial delivery system, would the brain still be conscious/sentient? It would obviously be unable to receive any form of external stimuli, but would it still be... alive? Able to think?

Remember I'm five, thanks!

[Assistant] Theoretically, sure, but the mind in there would go insane pretty quick. Sensory deprivation is not good at all long term. You need some way to simulate a body and environment for the brain-in-a-jar, or at minimum give it vision and hearing and control over a computer.


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

[User]
[Fallout 3] What do people do for a living? How do Tenpenny's inhabitants afford to stay there?

Medical practitioners still have a place in the world, as do engineers, armed security, store owners, sex workers, but what do all of the generic NPCs do? They can't all be prospectors, and most settlements (Rivet City, Megaton, Republic of Dave) don't see enough trouble for everyone to make a living as security.

As far as Tenpenny Tower goes, I understand the doctor and former slaver, but what does everyone else do? There's no Crimson Caravan or Gun Runners like in the West Coast for them to invest in, there don't seem to be any farms or ranches, there's no franchise of Super Duper Markets or Dots Diner for them to secretly own. One of them won't stop talking about communism, which baffles me since you'd think he'dve been lynched. What does *he* do for money?

I've heard fan theories that TP came from overseas, but that doesn't explain his wealth to me, where TPT gets its food, and brings in the new problem of who he convinced to accept pounds over dollars.

The only settlements that make sense to me are Paradise Falls and Rivet City. One seems self sufficient and insular, while the other probably deals slaves to foreign powers like The Pitt. I can't wrap my head around TPT or Megaton surviving. Canterbury Commons is 4 dudes with constant stop offs from caravans so its hardly even a village imo.

[Assistant]
Tenpenny Tower is living in the past. Its a bunch of self-proclaimed wealthy people who live as people lived in the past. They're pretending everything is normal and they're living the good life in this luxury hotel. However, they're not actually wealthy.

No matter how wealthy they claim to be, look at their actual inventories, including in their hotel rooms. They're no more wealthy than a random wasteland raider. The only thing Tenpenny Tower has in abundance is delusion and denial, similar to Andale.


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

[User] [Star Wars] The Sith are always going on about revenge. Revenge for what?

[Assistant]
The Jedi and Sith have a long history of fighting - in fact, the Sith were born out of a group of fallen Jedi.

About a thousand years prior to the rise of Palpatine, the Jedi and Sith had another major conflict which ended with the Jedi hunting down and eliminating most of the Sith with no known survivors.


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

[User]
[General Science Fiction] Why do so many technological advanced cultures and species have an inexplicable fetish for melee weapons?

The Kree, the Wakandans, the Klingons, the Imperium of Man and other WH40K races, the corporations and Dark Symmetry from Mutant Chronicles, all of the various techno-ninjas and samurai, the soldiers from the TV show Dominion, a variety of species from Star Wars, the Asgardians, and plenty of others I'm sure I'm forgetting. All have at least segments of their societies militaries who dedicate themselves to melee combat, despite the plethora of technologically superior options available to them. Why?

[Assistant]
It's usually one or a combination of three things:

**Tradition.** Sometimes the culture celebrates melee combat and views ranged combat as something less virtuous. Klingon, Jedi, and Yautja culture all agree on this, for example.

**Technology.** Sometimes the tech makes melee combat more practical. Jedi can deflect blaster bolts. Astartes have the speed to get in range quickly and the armor to tank hits. So do Protoss Zealots.

**Special circumstances.** Sometimes the situation forces you to fall back on old-fashioned ways of killing. In *Dune*, personal shields turn into nukes when you shoot them, so you gotta resort to slow-mo knife fights. In *The Forever War* there's stasis fields that neutralize all electromagnetic radiation, so you need swords to fight in them. Sometimes the enemy is resistant to ranged weapons, like in *Highlander*, *The Matrix*, and any *Star Trek* episode involving the Borg.


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

[User] Eli5 why the storms of Jupiter separate gases into striking vortices and bands of heterogenous color, rather than mixing them into a continuous gradient?

[Assistant]
First, there is the phenomenon of Hadley cells. These come about because the planet is round, spinning, and has one side facing the sun. These are pretty stable systems where the wind predominantly flows in a given direction. On Earth, these are responsible for Trade winds (winds strongly blowing west when a little north of the equator, then switch to blowing strongly east above \~30 latitude). On Jupiter, there are a lot more of these cells, each cell is one of the colored bands.

The vorticies that you see are the interactions of these two circulation cells.

The colors of the clouds come from two chemicals, Ammonia clouds (white) and ammonium hydrosulfide (brown)

On Jupiter, like on Earth, the atmosphere cools at higher altitudes. In the regions of the atmosphere where the air is rising, it reaches an elevation where it is cool enough that the ammonia condenses into clouds. These clouds are heavier than the air around them, but they are held up (and replinished) by the updrafts. In the regions where the air is falling, there is no ammonia to form clouds, and any ammonia clouds that are formed get pushed down to where it is warmer, so they evaporate. As a result, you can see the atmosphere below the ammonia cloud layer, which has a brownish color.

As a side note, Jupiter is big. Those tiny vorticies that you see would be continent-spanning hurricanes if they were on Earth.


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

[User]
ELI5: Magnets stick to each other, and magnets stick on refrigerators, why don't refrigerators stick to each other?

Edit: I'm surprised at how many downvotes this post got when this turned out to be a pretty deep subject. Doesn't really matter to me, though, I still got my answer.

[Assistant]
Your hand can grab a ball, and your hand can grab another hand, but that doesn't mean that two balls can grab each other.

Magnetic attraction is a property of the magnets, not necessarily a property of what they stick to.


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

[User]
Who decides stock prices? (because "supply and demand" isn't a conscious entity who can mentally make a decision or manually press a button to change the listed price of something)

So, I understand that prices (in general and in the stock market) are "determined" by supply and demand.

But, say I'm selling shirts. I have 100 shirts left and they're not selling well so supply and demand has "determined" that I need to reduce my price if I want to sell more shirts.

But "supply and demand" is neither a human being nor a robot. It is not a sentient being. It is not going to log into my POS and edit the pricing on certain products. Nor is it going to go replace my signage advertising $5 shirts with price tags and signage advertising $4 shirts. Supply and demand doesn't determine or change my prices - I do! I just make that decision based on the current supply/demand situation.

So. Stock market. NYSE. People either won't pay the price it's listed at, or they would be willing to pay more. Who changes it?? My understanding is that the price that's listed was just the price that was paid in the last transaction, but if I have to buy or sell it at that price now then how does my transaction change the price??

I know it's all made up and the points don't matter, but I also am really struggling to understand which sentient being picks the current going rate for literally anything.

[Assistant] In the stock market, people with the stock and willing to sell it set an **asking price**. If someone wants to buy some stock at the lowest asking price of anyone in the market, they can. People looking to buy a stock set a **bidding price**. If someone wants to sell some stock for a highest bidding price, they can. The price of every transaction is recorded and the price of the **last** transaction is what you see when you see a stocks price (or if you are looking during the day, this may be delayed 15 minutes or whatever the policy is to restrict day trading). If you are trading stocks, you see three prices, "bid", "ask", and "last". So the price is different if you want to buy or sell. And if you want to buy (or sell) a lot, you might have to find multiple people who have different asking (or bidding) prices to complete your order. The stock's **spread** is the difference between the bid and ask. Spread is lower on stocks with more sales volume.


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

[User]
If SARS-CoV (2002) and SARS-CoV-19 (aka COVID-19) are so similar (same family of virus, genetically similar, etc.), why did SARS infect around 8,000 while COVID-19 has already reached 1,000,000?

So, theyre both from the same family, and are similar enough that early cases of COVID-19 were assumed to be SARS-CoV instead. Why, then, despite huge criticisms in the way China handled it, SARS-CoV was limited to around 8,000 cases while COVID-19 has reached 1 million cases and shows no sign of stopping? Is it the virus itself, the way it has been dealt with, a combination of the two, or something else entirely?

EDIT! Im an idiot. I meant SARS-CoV-2, not SARS-CoV-19. Dont worry, there havent been 17 of the things that have slipped by unnoticed.

[Assistant]
SARS-CoV-2 is worse than SARS-CoV because, paradoxically, its not as bad. SARS tended to have a faster disease onset and be more severe, so you had far fewer infectious people with mild or no symptoms walking around spreading the disease. In fact much of SARS spread was in hospitals, rather than on the street.  That made it relatively simple to identify and isolate potential spreaders. SARS-CoV-2, on the other hand, has many people spreading it who are not sick and who dont isolate.

Even so, SARS was just barely controlled. People are complacent today, but SARS came much closer to being a pandemic than most people realize.


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

[User]
If Hubble can make photos of galaxys 13.2ly away, is it ever gonna be possible to look back 13.8ly away and 'see' the big bang?

And for all I know, there was nothing before the big bang, so if we can look further than 13.8ly, we won't see anything right?

[Assistant]
The early universe is opaque, so there's a limit to how far you can see before you hit this opaque region. The furthest we can see is back to the point in time when the universe got cool enough and thin enough that it transitioned from opaque to transparent. We're looking back in time with distance, so what we see is a sort of wall behind everything, a kind of *background* to the universe.

In this background we see the surface of the very hot gas that our portion of the universe evolved from. Over time, the light from this background has been redshifted down to microwaves. So this is the *cosmic microwave background*, and we have lots of maps of it.

One thing to keep in mind is that telescopes don't see "far", they're just good at capturing lots of light to see dim things, and at magnifying things to see things at higher resolution. So a low resolution telescope will still get the light from lots of distant galaxies, it just won't resolve them well enough to see them as individual galaxies - they'll just all get muddled up together. And a small telescope just won't capture many photons from these galaxies at all.

But the cosmic microwave background comes from all directions, so it's not too hard to detect. Newer instruments have just been able to map it in higher precision.


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

[User]
What happens to light when it is absorbed?

Certain lights are reflected and absorbed.

So what happens to light that is absorbed?

[Assistant]
If light hits an electron, the incident photon is absorbed and its energy transfered to the kinetic energy of the electron. With a higher kinetic energy, the electron enters an excited state, moving to a higher energy orbital.

The electron can then emit another photon and "jump back down", and the emitted wavelength of light will be whatever's allowed for the allowed transitions for that electron.


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

[User]
How large a colony must be in order to be genetically diverse?

Operating on a example - how many people would be required for a colony to avoid inbreeding?

Or to rephrase - how many generations must pass so offspring from the same n-grandfather could mate without consequences?

[Assistant]
The homo-sapien population is theorized to have dropped from around 21,000 to around 618 breeding individuals around 195,000 years ago. Due to the Long glacial stage known as Marine Isotope Stage 6 (MIS6) that lasted until roughly 123,000 years ago. This explains the lack of genetic diversity in modern humans.

They managed to produce 7.2 billion of us, with only 618 individuals.


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

[User]
[Arrow] What skills besides assassination does the League of Assassins teach? Would the League of Assassins make me a good DJ?

I've been thinking about spinning, but the general quality of DJs in Starling City seems to be pretty low.  I once heard that there was this DJ who was better than everyone else, but it turned out he was an agent of the League of Assassins.

I'm wondering, was he a good DJ before being recruited or did the League of Assassins teach him to spin?  Do you think they would teach me?  I'm not that interested in the assassination part, but I'm willing to make some sacrifices to learn how to drop a mad beat.  Are there any other vocations that the league of assassins might train?

[Assistant]
I believe all the training provided by the League is designed to further their designs so unfortunately you will need to become a master assassin but if you can convince them that you becoming a master DJ will help achieve what they want they'll probably allow it.

They do seem to be fairly relaxed during their non-training time though (they do have a hot tub) so it could be something you could learn in your personal time if another assassin possesses that skill.


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

[User]
[Fullmetal Alchemist: Brotherhood] If Pride happened to absorb Greed like he said he could, what benefits could that grant him?

Considering Pride's shadows are an extension of his body, would Greed's ultimate shield benefit Pride's childlike form, or would Pride's shadows be able to transform into an indestructible carbon-based substance?

[Assistant]
It's not clear that there would be any benefit to Pride, other than a small stroke to the ego.

 Pride, despite his small stature, is the de facto leader of Homonculus by virtue of his immense martial strength and power. This has to be somewhat embarrassing for Greed, who is very clear about not taking orders from anyone but himself, especially when the person giving out orders appears to be a child. When Pride threatens to absorb him, Greed backs off immediately because he knows that Pride could wipe him out in an instant. This shows a deference to Pride that the other homunculus seem to show as well.

When a Homonculus "dies" their powers can be reallocated to another physical vessel (e.g. the first body that contained Greed gave way for Greed to inhabit Ling's). This has got to be embarassing for Greed, as greedy people generally do not like having things taken from them, especially super powers. Pride knows this, and knows that he could kill Greed in an instant, so absorbing Greed is less of an injury and more of an insult.

Alternatively, we know that Greed's ultimate shield works by manipulating physical matter. It's not clear what Pride's shadows are, but they seem keen enough without needing the additional fortification of Greed's ultimate shield. A neat application would be deploying the shield between a light souce and Pride, creating the shadows necessary for him to use his powers.


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

[User] ELI5: How did Native Americans of the early 1700s cope with tornados?

[Assistant] Well there's tons of different Native American/Pre Colonization tribes. They all kinda viewed them different. In some parts they thought of it as evil, but a lot of tribes actually thought they could reason with the tornados, seeing them as spirits and healing. Lot's of tribes people also built communities that could easily be destroyed and rebuilt, so it probably wasn't as devastating for them when disasters hit. There is a lot of missing history though.


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

[User]
ELI5: How can grocery stores get ripe fruits of all types every single week of the year?

I understand that fruit can get sent by air all the way from Chile to the United States when it is winter in the U.S.  But even within the Northern or Southern hemisphere, it seems that harvest season is going to vary by latitude.  So, the regions in which cherries, or apples, or tomatoes, etc. are ready for picking will continuously vary every week.  How can grocery store suppliers constantly vary where they source their ripe fruit every single week of the year?  How can they have relationships with so many farmers in so many regions and even countries?  Is there a website farmers can use to tell suppliers all over the world when their fruits are ripe?

[Assistant] About apples specifically, they're harvested when they're in season, before they're actually ripe, then kept in cold storage for most of the year and released in batches. The low-oxygen, cold warehouse keeps them from ripening until they're ready to be sold.


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

[User]
ELI5: What's worse? The fact that you're inhaling hot, smoke into your lungs? Or the fact that you're inhaling actual cigarette ingredients (nicotine, tar, etc.) into your lungs?

What increases ones chance of getting cancer and other respiratory complications? Is it just smoking anything e.g. normal paper, crack, weed, etc.? Or is it specifically smoking cigarette ingredients? If someone smoked anything else other than cigarettes, as much as cigarette smokers smoke cigarettes, would their likelihood to getting cancer be the same as that of a cigarette smoker?

[Assistant]
Cigarettes are worse for your lungs than regular paper, yes.  Not that paper is OK to smoke - please don't smoke paper.  But cigarettes are worse.

Your entire airway, from your nostrils down into your lungs, is coated in mucus.  That sounds gross, but it's a good thing!  The mucus protects your lungs by acting like flypaper - any particles floating around in the air get stuck to it before they can reach the delicate membranes inside your lungs.  Dust, pollen, bacteria, and yes, smoke, all get filtered out by the mucus.  Most of it, anyway. If there's enough smoke, then some still reaches the lungs and damages them.  That's why smoking anything, even just paper, is bad.

Just like changing the filter on an air purifier, the mucus has to be "changed out" frequently.  Your body does this with little hairlike structures called *cilia*.  The cilia wave back and forth, constantly pushing the mucus (and anything caught in it) to your throat.  From there it drops into your stomach to be destroyed, and new mucus is secreted to replace it.  Your airway thus has a constant "conveyor belt" of mucus clearing out all the crap that you inhale.

Here's the "tobacco is worse" part: *nicotine paralyzes the cilia*.  So not only are you intentionally inhaling smoke, thereby saturating and using up all your protective mucus, but you're shutting down the conveyor belt to replace that mucus!  Your body can't clear out your airways anymore, making your lungs much more vulnerable to not only all the smoke you're inhaling, but anything else that could damage them, too.

If you talk to people who've quit smoking, they all tell the story of about two weeks after their last cigarette, they start coughing up this nasty black goo for a few days.  That's the "conveyor belt" starting back up again - their body is finally clearing out the old layer of mucus that's been sitting there, marinating in cigarette smoke, for years.


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

[User] ELI5: How can flash memory retain its data without power? Is it possible for it to lose data over extended period of time?

[Assistant]
Well, the thing about normal memory like the RAM in your computer is that information is stored based on whether electricity is flowing through the transistors within the memory chip. When electricity stops flowing through the transistors, they all reset to a default state and whatever was stored beforehand is lost.

Flash memory on the other hand is a type of electronically erasable programmable read only memory (EEPROM). It's sort of like a combination of RAM and ROM due to its ability to retain information without electricity as well as having the information stored on it be erasable and rewritten. Flash memory utilizes a "dam" system that is able to store residual electrons from electrical current regardless of whether there is electricity running through it or not.

There are 4 main parts to a flash transistor: a source, a drain, two gates called the floating gate and control gate, and an insulating material dividing the other 3 parts. They are in a o8o/inverted T shape, with the lower half being the source and the drain and the upper extension being the gates, with the control gate above the floating gate. The gates are surrounded by oxide layers through which current normally cannot pass through.

Negatively charged electrons are present at the source (the originating point of the electrical current) and the drain (the draining point of the electrical current) due to the type of silicon used to make these parts. However, they cannot flow naturally because of the electron deficient insulating material between the source and the drain. When you apply a positive voltage to the electrical contacts at the drain and the gates (the top and one side of the inverted T), the negatively charged electrons are attracted to the positive charge and get pulled to the drain. Some electrons also get pulled up into the floating gate through the oxide layers through a process known as quantum tunneling. Electrons that have gone into the floating gate remain there. These electrons are unable to escape the oxide layers, and will remain in the floating gate indefinitely. Flash transistors with stored electrons are akin to RAM transistors with current flowing through them. To remove the electrons, a negative voltage is applied to the electrical contact above the floating gate, which causes electrons to be repelled away from the floating gate downwards into the drain, through the same quantum tunneling process. This lack of electrons is then similar to a RAM transistor without current applied.

Flash memory has a certain number of program/erase cycles before it begins to lose its integrity. Degradation mostly occurs within the oxide layers that separate the gates. When the oxide begins to break down with repeated usage, it no longer is able to consistently prevent the flow of electrons in and out of the floating gate. Since the transistor relies on the electrons being unable to escape to store information, this causes the flash memory to become unreliable. It may still work, but may not work consistently or may lose information as a result.


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

[User] What makes some materials oven-safe but not microwave-safe or vice versa?

[Assistant]
The dielectric properties of the material.

In oven safe, the material has to take external heating, which will be a function of its heat transfer capacity ie if you heat it too fast, one area will expand too quickly, stressing the material and causing the break.

For microwave safe, the dielectric properties describe how well the material absorbs the energy, or how microwave transparent it is.  Ideally, you'd want a microwave transparent material so that only the food (particularly the water) absorbs the energy therefore heating/cooking the food.  If the bowl has a high dielectric constant, then the bowl will heat, causing the bowl to crack or be at a temperature much higher than the food being cooked.


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

[User] How does brushing your teeth clean your mouth, and has the invention of toothbrushes affected bacterial evolution?

[Assistant]
Toothbrushes mechanically helps in cleaning teeth by scrubbing off the dental pellicle layer that has been invaded with bacteria and thus preventing the formation of plaque and its accumulation, getting rid of food particles that remain on the tooth surface that might not be visible to the naked eye. Modern day brushes focus more on being less invasive towards the periodontal tissue (mainly the gums) and being more reliable in consideration to the time and amount of force that the consumer applies during their brushing sessions.  Also back then when toothbrushes were not around, people often used alternative ways to brush their teeth (see miswak or teeth cleaning twigs).

In relation to toothpastes and saliva they help in regulating the pH of the mouth that occurs due to by products of carbohydrates fermintation by the bacteria in the mouth, acidic pH increases the rate of demineralization of the dental enamel and limits the mineralization of the dental enamel. Also toothpastes tend to have prophylactic components that aid in the exchange of minerals between the tooth and the oral cavity and some have anti-microbial and others with periodontal-friendly components, but mainly saliva plays an important role in maintaining the oral balance and dictating its hygiene.


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

[User] ELI5: How is Pi programmed into calculators?

[Assistant] They don't need to put in the whole number. They just have to put it in to the point where the next digit won't change much at all. After the tenth digit of pi for example not much will change in your calculation.


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

[User] [Metroid] Why does Samus seem to start every new mission without any of her suits upgrades? Wouldn't it be smart to keep all the beam weapons, visor upgrades, and other suit upgrades she found on her previous missions?

[Assistant] She does keep her weapons at the start of new missions. She just has a very bad habit of getting hit so hard at the start of each mission that everything breaks and she has to find artifacts to repair everything. She's also lost her suit a couple of times and has had to have it rebuilt in a very short space of time because of extreme damage (Prime 3 and Fusion).


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

[User]
Will we ever know if Pi is a "normal" or "non-normal" irrational number? Is it within the realm of possibility that we will ever find out?

According to what I've heard, a "normal" irrational number is one whose digits contain every conceivable combination of numbers (including, for example, the social security numbers of everyone who has ever had an SSID in alphabetical order), while a "non-normal" irrational number is one whose digits are infinite but do not contain every possible combination of numbers.

So I guess I have two questions:

1) Will we ever know which of these categories Pi falls under

and

2) How is it possible to have an infinite number of non-repeating numbers without any patterns that **doesn't eventually run through every possible numeral combination?**

Edit: thank you for all the awesome answers! I now totally understand question #2 and **would like to propose another question** for anyone who sees this after this edit:

What is an example of a normal irrational number and **how can we prove that a number is normal?** (Is a normal number defined as any irrational number that contains all the digits of its respective base an infinite number of times...or...?)

[Assistant]
Not only do normal numbers contain every possible finite combination of digits, they contain each possibility infinitely many times.

The way that this is possible is that you do it by combination-length. There are only 10^(N) different possible combinations of digits of length N. So in a normal number, you can expect there to be one copy of any particular sequence of N digits in every N\*10^(N) digits of a number. You can try to convince yourself that

* 0.1234567891011121314151617181920212223242526...

is normal because it does this for every integer N.

We will almost surely prove that pi is normal or not sometime in the future. Though it is hard to prove things like this for numbers like pi, because it arises purely from geometry and so figuring out numerical things about it is hard. Generally, pi, as a number, is a very typical and boring. Almost every number is irrational, transcendental, normal etc, and the reason why we thought pi was these things is because pi should be like every other number. But accessing the arithmetic content of the number pi is hard to do, and so proving that pi is a boring ol' number is hard and interesting. Same goes for e and other numbers arising from other topics. Though, there are formulas for pi that are promising, as they can allow you to compute digits (which are part of the arithmetic part of pi) efficiently and directly. Not enough to prove that pi is normal, but it suggests that this information is not impossibly hard to obtain.


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

[User]
What would it take for research publications to be free from publishers?

Inspired by some recent discussions here, it seems like an overall consensus that publishers explore research work in a pretty unsatisfactory way. Charging exorbitant fees, using our work for their profits, etc.

So why do academics perpetuate this cycle, if they all agree that it's not the way it should be? Why be a reviewer for a journal and work for free? Why submit your work for publishers to profit? I understand academia requires the prestige that comes from publishing in such journals, and we do it to progress our careers...but once you become professors, or already established in your fields, why keep enduring these practices if you don't agree with them?

Why not make a change, and why aren't there any realistic alternatives for a truly fair publishing space?

[Assistant]
What is needed/wanted is a way to evaluate the quality and impact of research. There are very few people in the world that can truly understand the importance of most studies. So, journal prestige has become the surrogate measure for quality and significance of one's work. To be free from journals, there needs to be a different way to evaluate quality and impact, and realistically it needs to be relatively quick and easy (or nobody will adopt it). Some options that get mentioned are h-index and total citations. These are probably better, but they are far from perfect.

As a side note, convincing people that your work is high quality and high impact doesn't stop being important when you get tenure/established - you still need grants/money and you still need to recruit good students/PDs (who want papers in those journals so they can compete for good postions later).  Go a few years without those high profile papers, and the money and students disappear. You're never "safe."


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

[User]
[Blade; movies] Why don't the vampires wear sunscreen when fighting the reapers?

I just saw the first 2 movies, and am not familiar with the comics, so hopefully you will be able to shed some light on something that's been bugging me almost the whole time while watching part 2.

In the first movie, Frost comes outside during the day wearing sunscreen. In the second movie, the 'good' vampires go out and battle the reapers, but get their asses kicked themselves because of the UV-bombs and getting in the sun. Why wouldn't they just use sunscreen, preferably waterproof one?

The only things I can come up with breach the fourth wall...

[Assistant]
Frost was only able to pull off his trick because he was turned and because he wasn't exerting himself much.

Pureblood vampires are more sensitive to sunlight than turned vampires. This is most clear when Frost and his minions kidnap Dragonetti (the chief vampire) and roast him with an ocean sunrise.

All the members of the Blood Pack (those who were trained to fight Blade but then allied with him against the reaper strain) were purebloods and therefore wouldn't have gained much from sunscreen anyway.

Further, remember that when Frost used sunscreen he was just standing in a park. As soon as he got physical (throwing a child into traffic), he fled. If he'd gotten into a fight, his constant motion would have inevitably made his "mascara" run even faster.

The Blood Pack didn't try fighting the reapers during the daytime until their second encounter, which put them in the sewer. Not only would they be too physically active to expect the sunscreen to last, but it would rapidly come off with the vapor and water anyway. Along with making them even more detectable through smell, it simply wasn't worth it.


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

[User]
Why have Gold/Silver values not risen with Inflation?

We've all heard inflation, inflation, inflation for the last two years.

Why are gold and silver prices relatively flat since then?

Silver spot price for example has been fluctuating between 24 and 28 for the last two years with absolutely no upward trend.

How/why is it not slowly valuating with inflation?  Isn't this econ 101 stuff?

Thanks for reading.

[Assistant] Inflation is an aggregate. Individual goods and services all go up and down in price for their own reasons/their respective supply and demand. In fact it's quite rare that individual goods/services go up exactly as inflation does.


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

[User] ELI5: How do liquids stay homogeneous and not have settling issues, such as Coke or milk?

[Assistant] It's the difference between dissolving and making a suspension, when something dissolves into a liquid it becomes part of the liquid, think sugar in water, no matter how long you leave it that sugar stays evenly divided over the liquid. A suspension is tiny particles hovering in a liquid. If you give it enough time it will settle.  Like the kind of apple juice that still has apple in it.


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

[User]
[Dexter] Dex says he has no emotions. Except, he clearly does. He gets scared, angry, happy, remorseful, excited, nervous. What am I missing here?

It doesn't appear that this is something Dex grew into either. Teenage Dex is a seething mess of complex emotions - he regrets hurting his sister's feelings, he gets angry at his bully, he gets nervous that he's disappointed his father. And this before he supposedly learned how to "fake it". Even 20 year old Dex committing his first kill is a nervous and worried wreck, both from his father's impending death and from the stress of committing the kill. And Dex's private monologue is a cornucopia of emotional reactions, including sexual ones.

Far as I can tell, the only emotion he lacks is the ability to get freaked out by screams of terror. Is Dex just bullshitting himself, and the audience by extension?

[Assistant]
Dexter is a psychopath, or at least on the spectrum of what is now known as "Antisocial personality disorder" which Incorporated socio and psychopathy. He *has* emotions, but they're atypical and what he actually lacks is empathy and compassion. However, Dexter is probably not a "natural" psychopath in that his condition was the result of psychological trauma at an early age, e.g. witnessing the brutal murder of his mother. This means that his lack of compassion and empathy may be conditional, and seems to be so since he does seem to have these feelings for his family and for other victims, though much of that may just be moral justification for his compulsion for violence.

TL;DR: Dexter has feelings, but since he is callous, compulsive and selfish he has to work out intellectually how to act in order to appear normal.


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

[User]
[Halloween III: Season Of The Witch] What was the societal fallout of the Silver Shamrock commercial?

At the end of the movie, Challis is too late to stop the commercial from airing on channel 3.

Presumably, unless he had extremely good luck, this means that thousands of children died horribly on October 31, 1982, all across the country.

What happened after this event? Do people still celebrate Halloween? Did America blame the Russians? Are commercials now banned from TV?

[Assistant]
The mass murder was probably just the start. We don't know what the ritual was supposed to achieve, but it was probably a big deal. Society may have more important problems than trying to assign blame, like dealing with invasions of fae creatures or combating literal wizards.

And on top of that, androids exist now.


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

[User] ELI5: If we use degrees (  ) to measure angles, why do we also use degrees as a measurement of temperature?

[Assistant]
The most basic meaning of "degree" is "An individual step, or stage, in any process or scale of values."

There are 360 degrees in a circle because there are 360 individual steps. (You can fine-tune a degree using arcminutes (1/60th of a degree) or arcseconds (1/60th of an arcminute, or 1/3600th of a degree).

Similarly, there are steps in temperature. 1 degree Celsius is ever so slightly cooler than 2 degrees Celsius.


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

[User]
CMV: 'Jack of all trades, master of none' actually makes you worse at your profession

I'm a programmer who's interested in filmmaking. Far from being a polymath, I know, but I have been advised against it by people, reciting the old reliable "Jack of all trades, master of none" routine. I don't understand. Would tell polymaths such as Plato, Pythagoras, Newton, Da Vinci, and even modern ones such as James Cameron this? Some people believe in this so much that they limit themselves to their field, which might be extremely specialized. For example, would you trust a endocrinologist who doesn't know anything about psychiatry? All the diabetics go to him and he treats them like crap because "I'm not a psychiatrist, I'm an endocrinologist!" I had such doctor and I ditched him for a better one. That's not all. My new endocrinologist knows beyond medicine. He knows about psychology, philosophy, and even mathematics. That's what I like in my doctor: a polymath. Not someone like the last one who didn't know shit beyond his profession, and one might think this would have made him better at it... No, it made him worse at it.

I think anyone who coined the phrase "Jack of all trades, master of none" can go fuck himself. can you change my view?

[Assistant]
The problem with your argument is that you used the word "profession." If you are running a new startup or working in a newly invented field, you want to be a jack of all trades. You never know what skill set you might need next. But if you are working in an old field with very clearly defined and refined needs, it's better to specialize in that thing.

For example, doctors need to combine advanced scientific knowledge with humanist empathy. If they only have half that skillset, they aren't a good doctor. But they don't become a better doctor with other unrelated skills.

Endocrinologists are taught and tested on psychiatry in medical school. They also have to have an understanding of psychology, philosophy, and mathematics just to get into medical school. All of those things you describe are part of their required skill sets.

On the other hand, a polymath physician learns things that are completely unrelated. For example, being good at stamp collecting, long distance running, picking profitable stocks to invest in, etc. are all things that a polymath doctor might pick up. But they aren't something that would make them better at their profession (i.e., practicing medicine).


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

[User]
[Modern day D&D] I am a Kobold. In the past, my people were persecuted as monsters. Their murderers as heroes. Why did it take so long for humanity to accept that those who do not appear like humans were people too?

For centuries.. heck thousands of years parties of 'adventurers' were able to band together and go out and kill other peoples and be praised for it.

Textbooks and history classes say it was a 'sign of the times' and we can't truly blame them as it was just the way it was.  It wasn't until around the 19th century that we were seen as anything more than 'monsters'.  These days we have equal rights and are protected by laws but this wasn't always the case.

It just seems so crazy to me that this could be the case for thousands of years with no change.  Was the advancement of technology truly such a different thing than the magic we have always had?  I mean, there is the old saying that 'sufficiently advanced technology will appear no different from magic'.  Please help me understand!  I have a paper due in 2 weeks.

[Assistant]
Humans killed other humans for thousands of years too. For exactly the same reasons as humans killed kobolds. And you know what? Your kobold ancestors killed humans for the exact same reason that humans killed kobolds for thousands of years.

Have not read the histories of your people? It's as filled with stories of kobolds who slew humans by the thousands in 'their open sky dens.' But since those dark ages, kobolds have been in the forefront of technological and even magical progress, beating out other species in quite a few ways.


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

[User]
Can a venomous animal die if it bites itself?

I know that venomous animals can eat their own venom (since their prey is presumably full of it) but what happens if, say, a snake bites itself by mistake?  Would it be immune to its own venom?

[Assistant] This depends on whether the snake is immune to its own venom or not. Usually, venomous snakes have certain level of immunity to their own venom. There are those that have little or no immunity. They will die if they inject themselves with venom.


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

[User] ELI5:What's happening in my stomach that makes it "rumble" when I'm hungry and why does it do that?

[Assistant] The digestive system is one long muscular tube going from the mouth to the anus.  It uses a system of muscular contractions, called peristalsis, to move and break down food in the tube.  Sometimes gasses get trapped among the little bits of food and digestive juices.  During peristalsis, it's the movement of these air pockets that creates the rumbling noise.  When you're hungry, your body creates hormones which trigger peristalsis.  The vibrations of your empty stomach make you hungry and the peristalsis continues moving gasses through your digestive tract, thus creating the rumbling.


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

[User] ELI5: How can living organisms be alive if they are composed of non living atoms?

[Assistant]
Life isn't really some intrinsic quality like that. Life is more of a series of processes. If those processes are occurring, then the material is alive.

Think of a bundle of sticks. It can undergo the process of burning and be on fire, but it isn't necessarily on fire. The atoms themselves are the same either way, but only in some cases are they undergoing the process of burning.


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

[User] ELI5: why do you always get a distinct feeling/smell/ thing when you get struck in the nose or face?

[Assistant] I don't think the exact cause is known, but shocks to the brain - which could come through a blow to your face - can produce these odd (metallic?) taste sensations. They're common in concussions. Presumably a taste center in the brain is being knocked and playing up. You should get any potential concussion checked out in case there's a serious injury.