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

[User]
If I travel fast enough to red or blue shift radio waves, what would happen to the sound coming from a radio program?

I realize that I would have to adjust my station to the new frequencies, but would the radio beat or tone shift up or down as well?

[Assistant]
In both cases you would hear the signal speed up or slow down, and in both cases you would have to adjust your tuner up or down. Both the modulating (high frequency) and modulated (voice or music) signals are functions of linear-time (in opposition to time squared or the log of time), so if a 500THz red light gets shifted down to 400THz, your radio station at 100MHz will be shifted down to 80MHz, and the 1KHz test tone will shift down to 800Hz.

Modulation is cool because the modulated signal is still present in its original form. In the case of AM, you can pick it out by connecting the peaks or valleys of the modulated wave. In FM, you can pick it out by shifting the spectrum around -- which is incidentally exactly what happens when you have red or blue shift!

You could almost say that traveling at a certain rate is the same thing as single-sideband FM modulation!


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

[User]
ELI5: How do things catch fire without flame I.e just from heat?

My wife is adamant that things cant catch fire without flame. I know you can burn them with just heat, but cant really explain why. Save our marriage!

[Assistant]
>How do things catch fire without flame I.e just from heat?

The only reason a flame can set other things on fire is because of the heat it generates.  So the reality is that the **only** way to catch things on fire (ignoring unusual chemical reactions) is from heat, and other flames just happen to be one way to provide the necessary heat.

Also, ask your wife how you can light a match by striking it on a matchbook if it takes a flame to set things on fire.


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

[User]
[Wh40K] What kind of organs do the orks have?

So, the orks are more fungi then animal, but they obviusly have some organs, such as brain, lungs, stomach and probably something like a heart, since they have blood. But, what do we know of ork physiology?

[Assistant] Their brain is a symbiote of grey matter and fungus. Their organs are simplified. A heart and lungs like a normal animal, but a cavity filled with a kind of slurry performs the job of a variety of other organs (pancreas, kidney, liver, etc.) Their digestive system consists of a multi chambered stomach like a cow, and a crude renal system.


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

[User]
[Game Of Thrones] would things have faired any differently if Catelyn had loved Jon as a mother

In Season 3 episode 2 "Dark Wings, Dark Words" Catelyn admits to Talisa that Jon was sick and she prayed to the gods to heal him. In return she said she would love him as her own, and ask Ned to name him a Stark. She couldn't keep her promise and blames everything that had gone wrong on her mistake.

Would things have changed at all if Jon was a Stark and considered one of Ned's sons?

[I have watched the latest season so spoilers are fine!]

[Assistant]
Had Jon been legitimized and felt like a full fledged Stark, he would be unlikely to want to have joined the Night's Watch.

If that is the case, many of the events leading to the Red Wedding may not have taken place. He would have been an effective check to Theon, most likely preventing his coup and the supposed deaths of Bran and Rickon. Though to be fair, Theon may never have had the opportunity to stage a coup because chances are he would have been marching south with Robb while Jon bolstered and gathered troops in the North.

Also a legitimized Jon Snow would make Robb think twice about breaking his marriage alliance with the Frey's because (at least in the books) one of his main reasoning for marrying Jayne Westerling was concern over their bastard child.


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

[User]
[GENERAL] Why all (or almost all) fantasy medieval settings in fiction stays during the Middle Ages for thousands of years?

Like, Lord of the Rings and Game of Thrones, why do they stay technologically stuck in the Middle Ages without developing past that?

In our real world we got about 1 thousand years but then there was some scientific and technological and even social and economical and political improvements that made us evolve past that (and thats why we chose to call it another Age). But in fiction they stay there for 3, 4 or 5k years

Maybe the magic on those scenarios had to do something somehow?

[Assistant]
Depends on the setting. Sauron's orcs have gunpowder Saruman tried to industrialize the Shire. This is going to give technology a bad reputation and it's both harder and more morally fraught to cut enough wood for an industrial revolution when the trees can wake up and fight back.

Westeros is likely getting knocked back repeatedly by long winters. You need a food surplus and a stable population base to educate a lot of people.


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

[User] ELI5:Why is Lieutenant pronounced "Leftenant" by british people?

[Assistant]
(Some British people, and also all other Commonwealth armed forces, to be clear)

There is fair evidence (in terms of how the word was spelled in middle english) that both "lef" and "lieu" pronunciations have coexisted for some time.  The French word "lieu" (place) on which the word is based, is occasionally seen spelt in old French as "luef".

Codified spellings and pronunciations of words is a distinctly modern invention - for most of the time before, things were a lot more vague.


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

[User]
[Star Wars] I'm a Sullustan, but loyal to the Empire. Can I become a Stormtrooper?

If I can't serve in active combat, could I  possibly join the Imperial Navy?

[Assistant]
You'd have to be pretty outstanding with your skills, citizen. The Empire typically employs humans. Though, we're not sure if it's to help reduce costs by not having to create custom armor for your above average sized head, or if Emperor Palpatine is just a xenophobe.

If you'd like to serve your Empire, your best chance is to dedicate all your resources to them! Have you tried bounty hunting? The Empire has outsourced their work at times of need.

Long Live the Empire!


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

[User]
[Deadpool] how did the teenage girl find and contract wade to scare her stalker?

I don't see very many craigs list postings for mercenaries.

[Assistant] Deadpool got the job from Sister Margrets.  since this is a known hangout for mercs and a place for them to get jobs either she heard about it and posted the ad or more likely a friend of a friend did it for her.  Deadpool took the job cause he is ok taking a small potatoes job for a sense of justice and the fun or scaring the crap out of a creepy teen.


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

[User] ELI5: how is salt water separated from fresh water in rivers? They eventually lead to the ocean so where does the salt end and the fresh begin?

[Assistant] Rivers flow into the ocean.  The force of the flow is stronger than the tidal forces of the ocean until you get right to the edge between the two, and that's where the salt water takes over.  That line can move back and forth a bit between high and low tides, but in general that's why there is a separation.  A river is flowing outward and it pushes the salt water away.


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

[User]
[General Comics] Are there any Superheros/Villains who have never revealed their secret identity to anyone in their universe?

It seems like most superheros have trouble leading a double life and have to tell some close people, or they may get caught by someone, or just something causes them to reveal who they really are eventually. But are there any Superheros who have a secret identity, that have never revealed their secret identity to anyone except the reader, or come close?

[Assistant] The Joker has done a pretty good job.  Though there is a good chance that he himself doesn't accurately remember.  Even, the backstories that the reader sees are usually presented as possibilities rather than definite events.


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

[User]
CMV: The Gillette ad was actually an ad that promoted masculinity in a positive way

I think both sides are missing the point in the controversial Gillette ad. It never explicitly blames all men for being a problem in society. Rather, it bills real, responsible, respectful men as the SOLUTION to our problems. The ad shows examples of men stepping into situations where things are going wrong and they are taking steps to solve them. I would argue that because men are more inclined to be 'fix it' kind of people than women are (it may be a bit of a stereotype but I believe it has some basis in psychology and sociology), the idea of the ad is demonstrating what positive masculinity looks like: solving tough problems (sexual assault, 'boys will be boys') by setting a good example of how to be respectful but also be firm and assertive. Some of the men were very assertive in physically restricting the problematic person from continuing their bad behavior (for example a guy reaches out to stop a guy who is chasing after a girl and says something like "don't even think about it")

The ad isn't meant to paint men as being 'toxic' or being otherwise problematic (although I do wish the one mention of 'toxic masculinity' in one of the news stations shown in the commercial wasn't used) which I think a lot of people are construing it to mean that.

[Assistant] The ad was a blatantly cynical effort to reach a younger demographic with fake corporate wokeness. And the right-wing backlash was probably not only predicted, but seen as a benefit - outrage engagement is better than no engagement. One week ago Gillette was not a subject of debate and interest on social media and now it is; the corporate purpose of brand recognition and association with progressive masculinity has been served. Gillette could not care less whether men everywhere are inhuman monsters or they are ultra-progressive PC angels so long as they need to shave and can remember that Gillette is a cool brand of razors - the fact that the message is being talked about is far more useful to them than the substance of the message.


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

[User]
CMV: There is no 'sense of humour'

Someone describing themselves as having 'sense of humour' is as pointless as saying they breathe and live. There is no good or bad 'sense of humour' because humour is completely subjective.

My sense of humour is dark and witty. I don't like toilet humour or videos of people getting hurt while doing dumb stuff. Someone else can find those things funny but that doesn't mean that one of use has wrong or bad/good 'sense of humour'. Some people have very dry taste of humour but saying that they don't find anything funny is just wrong.

To clarify 'sense of humour' is different than situational sense. I wouldn't tell dark jokes at funeral even when I find is funny. And if we define sense of humour as being able to explain why something is funny or write good jokes then the ability is extremely rare and most people can't claim it.

Tldr; It's wrong to say to someone that 'they have no sense of humour' if they find your jokes distasteful. It's meaningless to describe yourself as having sense of humour.

[Assistant]
Humor isnt subjective, its inter subjective. Having a good sense of humor means having a sense of humor that other appreciate and appreciates others. We know a comedian is funny because everyone laughs.

Its like common sense  what common sense is, is based on what other people know, not what you know. A good sense of humor will be based on what other people find funny.


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

[User] Assuming the universe is infinite in volume; it would mean that any event thathas even the slightest chance of existing, will exist an infinite number of times, including humanity, including you... right?

[Assistant]
No. You misunderstand the concept of "infinite". Just because something is infinite, it doesn't mean it contains *all* possibilities, much less that each of those possibilities repeats "several" times, or an infinite number of times, or even once.

Take an example from an earlier one of today's  threads on mathematics: the number 0.1001000100001000001... (a) is clearly infinite, (b) is clearly non-repeating, (c) does not even contain all possible *numbers*, much less number *sequences*, much less *repeated* sequences.

Similarly, there could be an infinite number of stars in a steady-state, infinite and eternal universe, without a single one of them ever becoming a blue-white star of a specific size, of a specific composition, in a specific location,  travelling in a specific direction, at a specific speed, rotating at a specific rate, deteriorating at *another* specific rate, radiating a specific spectrum, and so on.


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

[User] ELI5: Why do we still use concrete and asphalt for our roadways? Why have we not found a better material that is less prone to potholes and always feels smooth to drive on?

[Assistant]
You could design and build a surface that is "better" in being more elastic and less prone to cracking.

However, asphalt and concrete are mostly just rocks with some binders in them. Quite literally nothing else you try to use will be as cheap, readily available, easily brought to site, and easily fixed.

There's more considerations in play than just making the best feeling road.


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

[User] eli5 Why did video games only work on channel 3?

[Assistant]
Early video game consoles had to use an RF analog signal to transmit a signal to a TV because dedicated analog and digital inputs like RCA, HDMI, and Component either weren't common place or hadn't been invented yet.

External devices like Video Game consoles, PVRs, VCRs, and DVD/BlueRay players weren't a consideration in those days so TVs either had an antenna hook up or a Coax for cable and that was it.

Very Early consoles like the Atari had a switch box that would plug into the antenna port (2 screws) on the back of a TV and would bypass the Antenna when the game console was running.

80's consoles like the Nintendo used a similar device that bypassed the cable coax because coax ports had since become standard on TVs. So you would plug the Nintendos gizmo in between the TV and the Cable TV cable. (The NES also came with an antenna screws to Coax adapter just in case) But because cable TV sends signals on multiple frequencies (each channel) the Nintendo's gizmo had to chose which channel to use. So they decided on Channel 3 and Channel 4 as they were the lowest channels and therefore compatible with every television set. There was a switch on the gizmo to switch between channel 3 and 4.

The Nintendo also had RCA video and audio out ports that would later become the standard for video game consoles until Component and HDMI cables became the norm.


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

[User]
ELI5: Why is footage from camera that was attached to you always shaky while you don't see same shaky effect through eyes?

Hey, why is it that when we use camera without OIS attached solidly to our body - we get shaky footage even though it was moving at same speed/distance/direction/force as our head.

While through eyes everything looked smooth and seamless?

[Assistant]
There's three things going on:

1) Our eyes automatically counterbalance the effects of walking; as we step up slightly during our gait, our eyes look slightly down (pretty much automatically) to keep our field of vision somewhat stable. Most cameras don't do this, so it's shakier than an actual person's vision.

2) Your brain screens out a ton of unnecessary or useless input. Remember, our retinas actually see a ton of blood vessels as well as a blind spot (and everything's upside-down), but our brain just removes all the unnecessary junk without us realizing it. Similarly, our skin is constantly sending all kinds of little signals to our brains as our clothes rub against it, the breeze blows, etc, but again our brain just filters it out. It's the same way with a decent amount of shakiness; our brain automatically stabilizes our view somewhat

3) We *do* see some shakiness, more than you probably realize. First-person videogame movement started to feel a lot more realistic when they added "head bob", where the camera moves a little as your character walks.


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

[User]
Is There Any Argument for the Family

I have been reading feminist philosophy and it is talking against family structures that ultimately are bad for women. Personal I find it  pretty convincing about how ultimately many things in the society such as the family structure with monogamous parents and children is responsible for a lot of the problems and oppression of women. Thus I was wondering if there was any argument against this feminist take on the family, since it seems that arguments for the family rely on tradition and thus are myopic to the problems that women face. Thank you.

[Assistant]
There are many arguments for the conventional, monogamous, nuclear family that is typical of modern Western countries. The fact that this arrangement is taken as commonsense by almost everyone, but those infected by modern academic and social theory find themselves asking whether there is *any* argument for it, tells us quite a bit about the ideological state of social theory.

Standard arguments for the family include that it is natural therefore good, that it provides a protective environment for the most vulnerable in society (children), that it is a haven from the ravages of civil society and industrial capitalism, etc.

Hegel is probably the most notable philosopher to provide an extended treatment of the family, in his *Philosophy of Right*. For Hegel, the family is a form of consciousness, in which the mutual recognition of partners in love acquires a substantial unity. Because the family is the ethical idea in its immediacy, it is constituted on the basis of subjective feeling (namely love, which Hegel regards as natural and essentially heterosexual in this context, because a unification of diverse elements). It is the first moment on the path through civil society to the state, and it ultimately depends upon the state, because its unity, in respect of its basis (subjective feeling of love) is contingent, and requires the necessity of law as support. As the initial locus of *feeling*, the family is indispensable for the education and protection of children, who are the expression of the love of the parents, and whose maturity is the ethical dissolution of the family.


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

[User] ELI5: How can a side affects of antidepressants be thoughts of suicide?

[Assistant]
The side effect isn't as direct as your post title makes it seem.

Rather it goes like this:

A heavily depressed person has suicidal thoughts/tendencies, however the depression is so deep that it negates the will/drive to do anything, including committing suicide.

On starting the therapy, the therapist realizes that any treatment will fail due to the absolute lack of drive and deep seated melancholia. He prescribes antidepressants. They work as intended and increase the depressive persons activity level, thus making them theoretically "fit" for treatment. However in doing so, the pharmaceuticals also increased the likelihood of suicide as the treated person now has enough drive/motivation to act, including potentially acting on their suicidal tendencies.

TL:DR
Sometimes the only thing keeping a depressed person from committing suicide, is their total lack of drive to act. Antidepressants may work just well enough to up the drive but not well enough to remove the suicidal tendencies.


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

[User] ELI5: Why is printer ink so expensive, while wildly coloured labels/product packages are abundant and apparently cheap?

[Assistant]
The reason printer ink is expensive is that the ink is where the printer manufacturers make their profit.

A company will sell you a color printer very cheap with little/no margin, or possibly even at a small loss. They make these printers so that they only work with the proprietary ink cartridges made and sold only by themselves. These ink cartridges are expensive and have a very high margin, and are where the company makes all of their money. Without the ink your cheap printer is useless, so if you want to use it you are forced to pay out for the expensive cartridges.


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

[User] Why do electricity pylons make a loud buzzing sound?

[Assistant]
Mains hum, electric hum, or power line hum is a sound associated with alternating current at the frequency of the mains electricity. The fundamental frequency of this sound is usually 50 Hz or 60 Hz, depending on the local power-line frequency. The sound often has heavy harmonic content above 5060 Hz. Because of the presence of mains current in mains-powered audio equipment as well as ubiquitous AC electromagnetic fields from nearby appliances and wiring, 50/60 Hz electrical noise can get into audio systems, and is heard as mains hum from their speakers. Mains hum may also be heard coming from powerful electric power grid equipment such as utility transformers, caused by mechanical vibrations induced by the powerful AC current in them.

Electric hum around transformers is caused by stray magnetic fields causing the enclosure and accessories to vibrate. Magnetostriction is a second source of vibration, where the core iron changes shape minutely when exposed to magnetic fields. The intensity of the fields, and thus the "hum" intensity, is a function of the applied voltage. Because the magnetic flux density is strongest twice every electrical cycle, the fundamental "hum" frequency will be twice the electrical frequency. Additional harmonics above 100 Hz or 120 Hz will be caused by the non-linear behavior of most common magnetic materials.


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

[User] ELI5:  Why does the department of Alcohol, Tobacco, and Firearms exist.  What do these things have in common?

[Assistant] ATF started out as an enforcement division of the IRS; it was responsible for those things because those things have special taxes applied to them. It was spun off in the 70s, and since the Homeland Security act it hasn't even been responsible for the taxes, but the history remains.


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

[User] [LOTR] If the ringwraiths were once powerful kings, sorcerers and warriors, why are there no records about who they were?

[Assistant]
Those kings fell to Sauron in the Second Age, something like 5000+ years prior to the journey of the Fellowship of the Ring.

How many records survive that long? Not many archeologists or libraries in Middle Earth.


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

[User]
Eli5: What's the behind the meaning of a "neckbeard"?

Can someone please explain what a neckbeard is? Why do they wear fedoras? Why the "le" in front of words? Is it an insult? I'm still pretty new to this and a bit lost?

[Assistant]
A decent beard should be, to at least some degree sculpted or manicured. Just basic hygiene really.

A "Neckbeard" refers to someone who has a beard not because they want one, but most likely simply as a result of inattention to grooming. Usually paired with wrinkled, smelly clothes, a surly attitude, and poor social skills.


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

[User]
ELI5: Why does Facebook change their look so much, and why are they forcing people to switch to timeline, AND when they make these changes why does it sometimes make your privacy settings go back to the default ones?

I mean, I know these changes are things you get used to...but I HATE timeline. I'd like Facebook to stay the same or at least similar. The changes never seem to make things better, more efficient, or even more appealing to the eye. They're just a bother. What the hell, Facebook?

[Assistant]
Mainly to increase the presence of ads, likelihood to click ads, and availability of ads.

Also to provide value so people will keep using facebook.

More shared information increases likelihood of others using facebook and data available to advertisers.


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

[User]
[The Incredibles] Why is there such a disparity in technology between classes

It is even more pronounced than in our universe. They seem to be at some point in the 60s, but there is advanced A.I., rocket boots, invulnerable cotton blends, memory erasing darts, etc. These all seem like things that corporations or at least the military would have capitalized on by now.

[Assistant]
It's like the Marvel universe and even DC, people with resources and inventions often tend to keep them pretty secretive for the purpose of protecting themselves or for being villainous.

Syndrome's tech is very sophisticated and his whole plan IIRC is to disperse it to the public to make everyone "superpowered" so there would be no supers. That shows how powerful this tech is and why it could potentially be a problem in letting it reach the public.


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

[User]
Do ants experience injuries from falling proportionately to their body size?

Would an ant falling a foot be enough cause for traumatic injuries? Or would they brush it off, like a dog or human would after falling from the same height? Does their tiny body mitigate falling damage somehow?

I shook an ant off my shower curtain and he hasnt moved yet. :(

[Assistant] Ants are very lightweight insects, and once dropped (in a few seconds), they achieve their terminal velocity and continue to move at the same constant speed. It is almost physically impossible to kill an ant from a fall.


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

[User] How does a neutron star generate a magnetic field if it is composed entirely of neutrons?

[Assistant]
Mostly because it's not composed *entirely* of neutrons - just nearly so.

The very outer layers of a neutron star are "normal" matter (as normal as 1,000,000 K matter can be, that is) and probably consist of a very dense fluid of nuclei and electrons. This layer is conductive, and so combined with the very fast rotation of the neutron star as a whole, can generate quite a whomping magnetic field.

Farther inside, as the pressure increases, we find a higher density of neutrons as degeneracy pressure fuses more and more electrons and protons. But still, there are some particles with electric charge to be found, and so a source for a magnetic field.

Even in the very center of a neutron star we're not completely sure what we'll find; but if there are free charged particles forming any kind of fluid, then again a magnetic field can form.


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

[User] [Who Framed Roger Rabbit] Are CGI characters toons? If so, are video game characters? What about stop-motion characters like the casts of The Nightmare Before Christmas and Coraline? What about characters animated in Flash or ToonBoom?

[Assistant]
CGI, stop motion, flash animations, all toons. They exist to entertain on the big or small screen and even though their origins aren't quite the same, they still have the exact same function and are just as lively and personable as old school hand drawn toons. They might congregate in different parts of toontown, but they're still welcome.

Video game characters are not. They exist only inside the technology of the cartridge/disc/computer. Real toons find some of the more toon-like video game characters offensive because humans only play to the stereotypes instead of portraying them as real actors and people. And a lot of times, some game companies just create pale imitations of the original and they don't get a dime in royalties, which can be a problem.


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

[User] Is it environmentally ethical to "litter" organic food waste, such as apple cores and banana peels, in ditches and grassy areas? Isn't that better for local ecosystems than it going to a landfill?

[Assistant] The envriomental impact is better if you toss food to decompose instead of putting it in a landfill. But as has been mentioned, it's better if you use a bit of common sense and try not to litter areas where people wouldn't want to have to deal with rotting food. It's best for you to start a compost pile at home. But, keeping organic waste out of landfills is a huge priority. Even though it breaks down, that soil is often contaminated by the other waste in the landfill thus making the nutrient contribution somewhat worthless.


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

[User]
[Lord of the Rings] Why did the elves leave Middle Earth?

My understanding is that they would regain their bodies in Valinor after their death. If they were going to Valinor either way, why not stay and fight? The rings were crafted by elves so you could easily argue they had responsibility to help.

[Assistant]
As an Elf, living in Middle-earth for long enough becomes an emotional/spiritual struggle. Imagine never dying, never aging, watching everything your people achieved withering away in the wake of constant war and entropy. Time becomes your primary villain, and nothing save the stillness of the Undying Lands can mitigate this constant sensation of unstoppable decay.

This is also why the three rings were so useful/problematic, as they granted a handful of lingering elves the ability to maintain kingdoms without fear of temporal decay. These heaven on earth realms were inexorably tied to the powers of Sauron, establishing the concept of the long defeat: no matter the outcome, the elves lose.

Getting to Valinor is technically the only option, given enough time. Any elves lingering in Middle-earth would fade over the eons, descending into wraithery or worse.


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

[User]
At what height does it become dangerous to jump into water?

I believe the high jump of most diving boards is about 30 feet.

So, at what point could it result in injury or even death if you jumped into water? Would a jump from, say,  50 feet be dangerous?

[Assistant] There's no answer that says water is dangerous starting from x meters. You can probably seriously hurt yourself jumping of the 30 feet diving board. Belly flopping from water level hurts pretty bad already, but wouldn't probably be ever harmful. While the world record for high diving is 192 feet.


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

[User]
Public schools should not offer sports or athletic programs to students at all. CMV

Athletics cost schools thousands of dollars because they often entails hiring sub-par teachers for the sole purpose of coaching a school sport (at least at my high school and in my area), taking up more property than necessary for facilities and fields which require maintenance and construction, and most importantly providing athletes with unfair treatment and the sense that athletics are more important than academics.

Furthermore on a collegiate level, class spaces are occupied by athletes whom solely made it to college through athletics and are paid to take up space in classes where many students must pay more because of the price of athletics and scholarships.

Basically, school athletics are a huge waste of money and drag down academics at the same time.

[Assistant]
First of all "academics" are not the sole purpose of school. School is to turn you into from little kid to a mature adult. Sports are a great way to built character, teamwork, and a work ethic, that no amount of school could give you. They help you form bonds with your team-mates and provide entertainment for the community.

Now to address your money concern, HS sports often make enough money from ticket sales and fund raisers to not only fund the athletics program but to ALSO help fund the academic facilities. This even more true on the college level.

Also as people have already pointed out, with obesity and health such a huge issue, we need to give students as much motivation as possible to get active.


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

[User]
[Terminator] Question about the use of time travel and the origin of Skynet

If Skynet and the Terminator models are reverse engineered from the remains of the T-800 from the original movie where does the original design or concept come from?

If Arnold succeeds in killing Sarah Connor or kills Kyle Reese befoe John Connor is conceived then in the future there will be no need to send Arnold back to kill anyone and there will be no T-800 remains to base any of Miles Dysons work on and Skynet never gets built.

Is there any way to piece all of this together and have it make sense?

Also why do none of them, including Skynet, seem to be aware that if they are successful in preventing their enemies' from existing they also prevent their own existence?

Edit: I just noticed there's another similar post from less than a day ago.

[Assistant]
The first three terminator movies occurs after various iterations of skynet is defeated in the future, and seeing that its defeat is iminent, skynet then attempts time travel to change history.  This destroys its original timeline, but creates a new timeline where an alternate skynet may succeed.

**Timeline 0:**  Skynet is created through normal means, judgement day happens, but skynet is defeated by John Connor and a number of his friends.  Skynet has however developed time travel and sends a T-800 back in time.  John Connor sends Reese back in time to stop him.  This time travel creates timeline 1 (timeline of Terminator 1).

**Timeline 1:**   In this timeline a number of John Connor's friends are assasinated by the T-800, and John is concieved by the future Reese, rather than whoever Sara Connor would have slept with normally.  in the original timeline Reese was *not* John's father.  T-800 is defeated, and Sara begins a strange new life.   Using the destroyed T-800, Cyberdine gets a leg up on developing skynet.  This skynet duplicated the judgement day of the original, but this timeline John Connor has recieved additional training and experiences and is once again successful in defeating skynet.  Skynet has still had time to develop time travel and so seeing its defeat, it sends the T-1000 back in time.  Alternate John Connor chooses to not send Reese back (likely there is no Reese in this timeline), but to send back a reprogrammed T-800.  This creates timeline 2, which begins with Terminator 2 movie.

**Timeline 2:** In this timeline, cyberdine systems is heavily damaged by the T-800 and Sara Connor, and much of the research is lost.  Their main programmer is also killed.  But enough information is left that the military recreates Skynet *again* at their base.  This skynet causes judgement day, but is again defeated by John Connor in the future.  Skynet-2 has still devleoped time travel, and so it sends back the female terminator, and the resistance sends back another T-800.  This creates Timeline 3, the events of terminator 3.

**Timeline 3:**  In timeline 3, John Connor and the terminator rescue his future wife, and take her to the military base, in an attempt to destroy skynet.  They are too late, and judgement day occurs, but this time John and his future wife end up in a very defensible bunker where they once again lead the resistance.  This leads to terminator 4, which is a continuation of Timeline 3.  In this movie we do not see skynet defeated, so we do not know if it has developed time travel and will once again alter time if it loses.

The key thing here, is that skynet knows each time it sends a terminator back, its destroying its own timeline.  So it only does so when it knows its lost.  Skynet considers *any* alternate timeline where a different skynet defeats humanity to be an acceptable solution, but only if it has no chance of victory in its own timeline.


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

[User] ELI5: why do we say a pair of underwear when we are only wearing one?

[Assistant] A pair of pants really used to consist of three separate parts (left and right leg and middle) and even longer time ago it was like just the 2 leg parts that got tightened to the legs and longer clithes for the upper body for males and females. These clothes were common till the 16th century.


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

[User] ELI5: Why do flies like landing on humans? What are they getting out of it?

[Assistant]
Your skin is full of salts, loose cells, moisture and other delicious things flies like to eat, even more so during warm weather.

Look closely and you'll see the fly walking around on your skin with it's mouth-tube (forgot the name) prodding around on you. That's the fly eating off you.


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

[User]
[Harry Potter] How do you become a "better" witch/wizard?

So far, it seems spells are just incantations and you just point a wand and it work. So how can someone be a "better" wizard? Is it some kind of knowledge? Or is it more physical/willpower based? Or genetic?

For example, can Neville be as strong as Voldemort or Dumbledore if he just keeps learning more and more about magic? Basically, how the hell are you a better wizard than someone else? You both have a wand, and both say the same spell.

[Assistant]
You can see in the books that minor mispronunciations or mistakes while making wand movements result in miscast spells. That inattentive people blow up their cauldrons while others make them perfectly.

A better wizard would be one who takes the time to study properly and become the best they can be. So an average wizard might be satisfied with getting a Wingardium Leviosa down to the point he can do it when he can cast the spell when he concentrates while a great wizard would practice until he gets to the point where the swish and flick happen with muscle memory.

An average wizard might just follow the instructions in a potions book but fudge the time a bit and come out with an okay potion. A great wizard who puts in the work might find shortcuts or ways to maximize the ingredients and come out with a better potion for the same amount of time and effort the average one does.

It's just a matter of putting in the work.


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

[User]
[Halloween] How intelligent is Michael Myers?

This came up in a different thread where his intelligence was perceived as being higher than Jason Vorhees'. I ended up agreeing, though now that I see it, I'm thinking Myers might actually be a genius?

[Assistant] Depends on the universe we're talking about, but I'd agree that he's smarter than Jason. Jason was isolated from the world for a long time and suffered many head injuries from his victims, whereas Myers at least had opportunities to learn.


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

[User]
[The Culture] Humans get slap-droned when they kill someone or do something really terrible, what about Minds?

Considering that human murderers usually suffer a social death along with a drone to follow them around to assure that they "don't do it again," why aren't there any effective deterrence for psychopathic Minds such as Grey Area? as they only seem to experience one consequence of terrible actions. Since slap-drones are sentient, couldn't they just get a more powerful Mind ship to follow a Mind around to make sure they don't do it again?

[Assistant]
They do.  The *Sleeper Service* was effectively 'slap droned'.  Various ships were assigned to follow it around over the years.  *Sleeper* didn't even do anything, it was just an eccentric Plate Class GSV.  Other ships in the Culture felt they should keep an eye on it.

Minds really operate on their own level.  If a ship wanted to follow Grey Area around, it could.  It seems the response all the ships chose for what Grey Area did (read sentient minds without permission) was to insult it and call it Meatfucker.  That was considered a 'big deal'.


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

[User] ELI5: Why does cheese 'sweat'?

[Assistant]
The 'sweat' is actually oils from the cheese.

Think of the cheese like a sponge holding in water.  When its freezing, the water stays in the sponge.  When it thaws, the water starts leaking out.

Oil has a different boiling and freezing temperature than water.  When you keep cheese in the refrigerator, the oils stays in the cheese easier (Although is may sweat a little over time).  When you take it out, the oils start leaking out.  However, because oil evaporates much more slowly than water, the oils tend to just sit on the surface of the cheese.


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

[User] ELI5: Why do women live longer than men on average?

[Assistant]
Men take more risks.   "Hey, look, no han.........."

Men are more likely to work in more dangerous jobs.

The way men put on weight, etc is more likely to lead to cardiovascular disease at an earlier age.

Men are more likely to not seek medical attention for injuries and disease.

Men are more likely to be the victims of violent crime.


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

[User] ELI5: Why Is Diesel Preferred Over Petrol for Large Vehicles?

[Assistant]
Torque, or how much force a motor can apply to the wheels at a given RPM.

Diesel engines have a much higher compression ratio that gasoline engines. They work by squeezing their air-fuel mixture so much that it spontaneously explodes. Higher pressure in the cylinder delivers more turning power to the crankshaft, which is transferred to the wheels.

The disadvantage to this is you need heavier engine components to withstand this violent force. This limits how fast the engine can turn. So diesels tend to produce most of their power at low RPM.

Now if you're hauling a heavy load, that's exactly where you want all your engine power to be. You need that kind of force to get you moving, and most diesel vehicles don't need to go very fast. Nor do they need high acceleration.

Now you could produce a gasoline engine that could match diesel torque levels. You see this in aviation engines, which need to produce a lot of turning force, but also need to be light. The problem is that gasoline will spontaneously ignite at a much lower temperature and pressure than diesel fuel. This causes a problem called knocking or detonation. The fuel prematurely ignites before the piston is at the top of the cylinder. This can severely damage engine components. Thus you need to introduce additives (boost the octane value) to reduce the ignition temperature. Unfortunately, doing so significantly increases fuel costs. Aviation gasoline (avgas) is usually around 100 octane. The average price today (Aug 13, 2016) is between $4.67 and $5.29 per gallon, depending on where you are in the US. Double the cost of diesel. Most avgas is also still leaded. It's a far more convoluted way to do things when there's a better and simpler technology available.

Diesel can also be more fuel efficient than gas as well, which is important for the long haul industry. It has a higher energy density. Which means you can get more work done with less fuel, even at those low RPMs. It's a little less efficient at high speeds though. A fine trade off for trucks, but it's partly why they're not common in North American cars.

A third advantage of diesel is it scales up in size quite well. The limiting factor becomes the transmission. You need a lot of big, robust gears if you want to directly drive the wheels. Train locomotives and ships use a diesel-electric transmission instead. The engine turns a generator which powers electric motors attached to the wheels/propellers. Electric motors produce a near constant torque across their entire RPM band. They don't need to be geared either, making them ideal for very large loads. Of course for a truck, this adds unnecessary complexity.

Fully EV trucks will eventually replace diesel once battery life and recharge times improve. When you're getting paid by the mile, you can't really afford to wait a couple hours to refuel. Some trucks of the future may even use overhead lines like the Accela Express and other electric trains.


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

[User]
[John Carter] So... what/who is John Carter exactly?

I haven't read the books for a while, but I recently watched the movie and was happily surprised by it. I always thought that it was shit and that's why it failed so miserably, but as far as fun space-opera type adventures go, it was a good ride. However, it got me thinking of something that I didn't really put much thought into years ago when I picked up the written versions of the stories.

One thing that I don't remember actually explained in the books, and that certainly wasn't explained in the movie, is that I don't understand who exactly John is. Or should I say, WHAT he is?

What I am referring to specifically is when this is mentioned:

>"I am a very old man; how old I do not know. Possibly I am a hundred, possibly more; but I cannot tell because I have never aged as other men, nor do I remember any childhood. So far as I can recollect I have always been a man, a man of about thirty. I appear today as I did forty years and more ago, and yet I feel that I cannot go on living forever; that some day I shall die the real death from which there is no resurrection. I do not know why I should fear death, I who have died twice and am still alive; but yet I have the same horror of it as you who have never died, and it is because of this terror of death, I believe, that I am so convinced of my mortality."

So, he has always been a man of around 30 years old.  I think it also mentions that he has lived to see his relatives of several generations grow up from childhood into old age, yet he personally has never changed.

So, what is he? On Mars he is a "superhero" because of his combat prowess combined with the lowered Martian gravity, giving him incredible strength and agility. But that doesn't explain why he doesn't age at all. At first I thought he may be a Thern or something, but then I realized that in the movie, the Therns are portrayed much differently than in the books. In the movie they are beings from outside of both Mars AND Earth, never aging (but not immortal), so I thought hey maybe he's some kid of lost Thern, but then I remembered in the book series they weren't even mentioned in the first book and were actually just another species of Martian humanoids.

So that leaves me back to the original question.. is it ever mentioned where John Carter really came from, or how he acquired his gift of long life?

[Assistant] Unfortunately, there is no definitive explanation for John Carter's remarkable longevity. It's possible that one or more Barsoomians traveled to Earth in the past, and that John Carter is descended from them. It's also possible that John Carter isn't alone - there may be other sword-fighting immortal humans who live among us...


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

[User] Why is it so hard to remember our dreams but not our memories?

[Assistant]
The basic idea is based on the number of neurological pathways that are activated. This can be observed in a few different ways.
First and foremost, most memories that we do tend to remember are associated with strong stimuli, whether that be a smell, taste, pleasure, pain, etc. This also explains why we have an easier time remembering vivid dreams and nightmares.
A second way to explain differences in neurological connections has to do with your state when you are thinking of these things. Often times you wake up and move on with your day before really thinking much about your dream. This is contrasted by memories in the sense that you most likely would be wide awake when the memorable instance occurred.
To expand on the basic principle, it helps me to put in in terms of the way we learn/memorize things. The first time you do something, you're just creating certain neurological pathways. Through repetition, previous pathways are solidified and additional pathways are created, leaded to enhanced ability to recall the information. You are essentially moving items in "short-term" memory to "long-term" memory.

**TL;DR** Greater activation of neurological pathways with strong stimuli, we don't (usually) take time to think about our dreams. This is similar to how we learn/memorize new information.


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

[User] [James Bond] What happened to Jaws and his girlfriend after the events of Moonraker?

[Assistant] Jaws gave up his evil henchman ways, in order to become a family man. They settled down in a nice suburban area in America and Jaws went in to construction, where he eventually became foreman and saved enough for some extensive dental work. They lived pretty much happily ever after, except for an accident that resulted in a nail getting shot into Jaws' skull, but it was safely removed at a later date.


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

[User]
ELI5: How TV Networks find specific clips of things that happened decades ago?

I was just watching The Late Show with Stephen Colbert and they showed a couple of old clips with contradictory statements by Alan Dershowitz, just seconds of videos from decades ago. Everytime I see something like that I wonder: How TV Networks catalog all these clips in order to find them when they're useful for their purposes?

Edit: I don't mean the database where they get those clips from, but the actual process by which they manage to find a specific clip of something that happened decades ago. In my example, do they have to go through everything that guy ever said on TV to know if he said something related to the current topic? Is everything transcribed? How is the actual search process?

[Assistant] Most major news organizations have vast archives of video clips of broadcasts/major news events that companies can subscribe to and go through to grab clips from. And in the case of cable shows like The Daily Show/The Colbert Report their parent company Viacom owns a news agency directly so they probably don't have to pay for the subscription rights to use the clips.


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

[User]
[Marvel] So exactly how do I go about proving that I am "worthy" to Mjolnir?

What philosophical tenets does this hammer use to evaluate my worthiness? Does it judge me by my motivations or by my actions? Is it judging me by Asgardian standards or Earth standards (and for my current time period ... for you time travellers out there)? Or is there some absolute or universal measure that it is using? If so, who the hell came up with that universal metric and what makes him think he's correct?

Also, if Thor's society is actually a highly advanced technological one (and not really a "magical" one), what kind of tech might have been incorporated to judge my moral character?

[Assistant]
The magic is based on Odin's standards of heroism. Honor, fairness, chivalry, bravery. A wielder of Mjolnir must be mighty in arm and noble in virtue and deed, always seeking to protect the weak and face down evil.

The hammer isn't designed so that anybody can wield it if they fit some random metric; its designed so that Thor can wield it. Conversely, anyone who is Thor's equal can wield it, for "Whosoever holds this hammer, if he be worthy, shall possess the power of Thor".

So what makes Thor so great? Well, he's a noble warrior and hero who has dedicated his life to fighting for a completely different species of people (humans) and being our protector just because he feels its the right thing to do. He's basically the pinnacle of Asgardian chivalry, and despite his occasionally proud and arrogant nature you'd still be hard pressed to find a more honest or generally kind individual.

And no, you can't trick Mjolnir by having good intentions. It knows you by thought and deed. Though a person can eventually earn the right to use it, or be granted the right, if they didn't possess it before.


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

[User] ELI5: why are things more funny as a kid?

[Assistant]
Things stop being funny when you've seen them too often - and this isn't just true of specific funny things, but entire classes of funny things. Seeing someone get a custard pie in the face isn't all that funny when you've seen it a lot.

When you're young, everything is new, so it has a lot more chance to be funny.


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

[User]
[LotR] What did the rest of Bilbo & Frodo's lives look like, after they took the boat?

I get that the elves will live happily and forever in the Undying Lands, but what does that actually mean for non-elves?

[Assistant]
Bilbo, Frodo, and eventually Sam go to Tol Eressa where they will live out the rest of their days in a land where their ailments can better be treated (not cured). Itll be much like Lorien but greater.

Mortals dont gain much of anything simply by inhabiting the Undyling Lands, thats part of the tragedy of the Akallabth (destruction of Numenor), theyre called the Undying Lands because thats where the immortal inhabitants of the world live, not because the land makes it so.


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

[User] ELI5 - How does anti venom work?

[Assistant]
You might not like this... antivenom is assorted antibodies that target the venom in your bloodstream. You make it by taking the venom from the snake with the venom, then injecting it in an animal, then harvesting the resulting antibodies from blood drained from the animal.

This is different from antidotes used against toxins, which tends to be more specific. The opioid antidote naloxone for example "knocks" the opioid receptor free and takes the place of the opioid for a short time.


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

[User]
ELI5: How does the throat know the difference between food/drinks and air, allowing it to push the food/drinks or air to the right place??

I think the title says it all. What role does the Adams apple play in all of this? How does it move out of the way for food/drinks?

[Assistant]
The throat doesn't push air anywhere, it is drawn in by the change in volume of the lungs caused by the diaphragm. The sheet of muscle which is the diaphragm pushes your abdominal organs down and expands the volume of the lungs, drawing in ambient air from the decrease in internal pressure.

Food and drink are sensed by the nerves within the mouth and the muscle cycle of swallowing is triggered. The part of the throat that carries both food/drink and air is called the pharynx, and it splits into the esophagus which only carries food/drink to the stomach and the trachea that carries air to the lungs. This splitting point is where the epiglottis is, a flap of tissue that covers up the pharynx when you swallow to prevent food/drink from making its way into the lungs.

At the top of the pharynx is the larynx or "voice box" that contains a pair of vocal cords which vibrate to produce the sounds of our voice. The Adam's Apple or "laryngeal prominence" is a shield of cartilage that lies between the larynx and the outside of the throat. It is not inside the larynx so it doesn't need to go anywhere to let air through, and it isn't part of the pathway for food at all so it doesn't need to "move out of the way" of food/drink.


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

[User]
Are humans getting taller?

Ive read that Americans, on average, have stayed the same height for the past 50 years. Is this true even now with the amount of immigration from Latin America and Asia where people tend to be shorter on average? Are millennials taller than their parents? Has the age at which we stop growing decreased making young children of this generation taller than the previous generation?

[Assistant]
In general, living conditions would be a bigger factor than genetics as how tall people get within the specified time period (50 years). It is said that North Koreans are, on average, three inches shorter than South Koreans due to poor living conditions in the North.

Things like better nutrition, better healthcare and lack of corporeal punishment on women and children with sticks thinner than your thumb all lead to taller people.


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

[User] ELI5 Why is blood slippery (like soap) when you wash it off, but otherwise sticky like glue?

[Assistant] Platelets in blood causes it to be sticky when dried on your skin. They pile together to close off open wounds and give the bleeding area a temporary gelatinous shield from foreign contaminants. Your platelets also work underwater, thickening and sticking to your skin. A bar of soap does a similar thing, sticking to your skin and slowly rinses off with more water.


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

[User]
I see no reason why a foreign-born, naturalised citizen of the USA should not be eligible for the Presidency.

The Constitution requires that the President be born in the States, which excludes naturalised citizens; people who have actively selected to live in the States, rather than those who have had the luxury of being born here through no choice of their own. If all men are created equal, it cannot be justified to claim that an American born in America has more right to the presidency than a foreign citizen who has chosen naturalisation.

Foreigners can run for the Senate, for the House, and can sit as Governors. Arnold Schwarzenegger sat as Governor of California, for example, and no one had a problem with that.

[Assistant]
The best argument I've heard is that, unlike those other positions, the president is supposed to be the leader of our foreign policy.

Whether a foreign-born president would inevitably favor his home nation more than is best for the U.S. is of course imponderable.

However, such a president would always be *viewed* as favoring their home nation, which would hamper the effectiveness of our foreign policy.


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

[User]
Since a star has used up its hydrogen before it goes supernova, how does the resulting gasses give birth to new stars?

Wouldn't there be a lack of hydrogen to start a fusion reaction?

[Assistant] A star doesn't use up all of the hydrogen in the whole star, only the material in the core can fuse. The outer layers of the star, containing most of the mass, aren't burned. Some mixing can occur by convection as the star ages, but for the most part the composition of the core will be very different than the composition of the outer envelope. The hydrogen in the outer envelope isn't burned, so when the supernova happens it seeds the area nearby with not only the metals in the core but with the hydrogen and helium that still make up the vast majority of the mass of the star.


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

[User] ELI5: when a huge skyscraper is built, how do they get the cranes and construction equipment down from the top when complete?

[Assistant]
Each situation is different... but it's usually some version or combination of one of these basic methods:

1) The "big" crane is dismantled and brought to the ground by a smaller crane. Compared to the building parts they lift... cranes are relatively lightweight in small pieces... so they can be carried by smaller/mobile cranes.

2) Same concept but the big crane is disassembled and lowered using its own structure or the building as a support system.

3) (less common) The bulk of the crane support is designed into the guts of the building and is essentially abandoned... or there actually is no "tower" and the crane is simply lifted as the building goes up so there is very little to take down at the end of the job.


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

[User] ELI5: How do fighter jets know when they're being locked on to?

[Assistant]
Lock on for radar guided missiles involves, well, radar. If you are having radar beamed at you, that can be detected. Fighters have radar warning recievers that let the pilot know if they are being "painted" and by what type of targeting radar, as different models have different characteristics.

Infrared guided missiles (heat seeking) are much trickier though, because they don't emit anything. For those, you need luck and a good visual system, either via your eyes or an automatic camera based system.


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

[User]
CMV: its not okay to reach out to someone you didnt match with on other social platforms just because you saw them on Tinder/Bumble

I dont have my social handles listed on any of my dating profiles but Ive still had people be able to find my Instagram as some of them go to the same college as me and we have mutual followers. I dont think this is okay as the fact that we didnt match should indicate that I may not be interested, and it sometimes makes me uncomfortable being randomly reached out to. I also know of women whove had someone who found them on tinder (one whom they matched with and one whom they didnt match with) find them on Facebook and message them, and as we know last names arent listed on Tinder and Bumble, so its very creepy to me that there are guys who will go out of their way to find someones socials just because they saw them on a dating app.

Ive had people say Im wrong to take issue with guys reaching out to girls they didnt match with on tinder and bumble as they dont have bad intentions, but I think the issue for me is respecting boundaries as it does feel invasive. But Im willing to have my view on this challenged because maybe I am being too hard on these guys, or maybe Im being a little mean.

[Assistant]
If they dont want unknown people contacting them on other forms of social media, they should disable the option for people they arent friends with to message them.

I agree, this is like the first step to stalking. But this is like leaving your door unlocked and getting ~~upset~~ surprised when someone walks in uninvited.

Edit: Should people know better? Yes. But we live in a world where people have many personalities, and unfortunately some people dont. This is reality. Locks exist for a reason, as do privacy settings on social media.


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

[User]
[monty python: holy grail] I have just burned a witch after weighing her to see if she weighs as much as a duck! But now I have pondered something: if witches are indeed made of wood, then she was a puppet, and if she was a wooden puppet, then another witch created her!

So, witch came first, the puppet or the witch?

[Assistant]
stop that!  stop that!  this question is entirely silly.  And now for something completely different.

Two young witches are sharing a cuppa while a knight and a frog engage in an epic battle of verbal wits.


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

[User]
Sex is not inherently harmful to children. CMV

What rights do adults have to deny kids their sexuality?

Human beings are sexual beings, from conception.

Babies touch their genitals and feel good about it. So they repeat time and time again.

As they grow older, they continue to seek and find pleasure out of touching their bodies, they discover where and how they like to touch and be touched.

Preteens and pre-puberty kids are just absolutely curious about their bodies and of their piers male and female.
They start having a lot of intentional pleasure by touching and rubbing themselves.

And obviously during puberty their sexuality flourishes, they do learn and seek pleasure out of sex.

So why do we insist that kids cannot have sex, feel pleasure and show themselves? They like it! Showing themselves is part of their sexuality, most do enjoy it . They show and they see. Kids are eager for porn, they learn through porn.
And today kids have a lot more knowledge about sex and their bodies thanks to porn that is freely available.

A 13 year old boy does not always have the chance to see a naked 13 year old girl if not through porn. Why deny them this growing and learning experience?

If kids did not enjoy sex we would not find so many of them on Omegle and the likes. They are there. They want to show, they want to see, they want to have pleasure! It's their right.

Adults do not have the right to deny them this their right.

[Assistant]
>So why do we insist that kids cannot have sex

Because humanity has transformed sex from a purely animalistic means of reproducing to something emotional, valuable, and meaningful.
By exposing children to young to understand that side of it, you permanently inhibit their ability to truly grasp how meaningful sex should be. They never move past the animalistic urges in relation to sex, and it ruins their ability to understand a healthy sexual relationship.


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

[User]
ELI5: Why does stress tend to decrease performance at complex tasks?

I speed solve Rubik's cubes as a hobby, and I've noticed that my solve times are consistently worse when I'm feeling anxious about my performance than when I'm relaxed and in the moment. However, I've heard stress and anxiety described as a response by the nervous system meant to heighten an organism's performance in high-stakes situations. Why would stress cause me to perform worse at this task instead of better?

[Assistant]
The stress response evolved to improve our performance at a very specific set of tasks: fighting or running for our lives. So things like energy, blood flow, and stuff like that improve. But some things also get worse at the same time: notably for your example, rational thinking and fine motor skills.

It's possible, with experience and practice, to reduce the bad parts.


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

[User]
If time is relative, does the age of the universe have any meaning?

I've watched plenty of layperson science documentaries in my time. Enough to know that the universe is about 13.8 billion years old since the big bang. But if time is relative, then how would giving a specific age of the universe make sense? I mean, if I go on a space ship and travel at 99% the speed of light for one of my personal years and back, then I'll have aged 2 years, and Earth will have aged hundreds of years or something. But both Earth and I are "the universe." The part of the universe that is me is younger than this other part of the universe! And inside black holes, time has stopped, so the time in there should be 1.5 billion years or however long it took to form. It just seems that with all these different ages for different parts of the universe, having one number for the whole thing is a little silly. It would be like spinning a baby around by the legs at 99% the speed of light, then celebrate it's 1st birthday while it's legs are old and wrinkled (okay, maybe that's a little more silly, but I think I made my point).

Thank you to anyone who takes the time to enlighten me!

[Assistant]
There is a frame in which the Universe is older than in any other frame. That's the one we are using when we refer to the age of the Universe.

It's called the cosmic rest frame. In this frame (and only in this frame), the cosmic microwave background radiation appears isotropic and nearby galaxies are (on average) at rest.


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

[User]
Do transplanted organs also replace themselves every 7 years?

Edit: I am curious specifically about kidneys if there are different answers to different organs. Also, kidneys have been known to work in the recipients body for over 20 years so don't tell me it isn't there long enough to replace itself.

[Assistant] Worth noting that the cells that replace those transplanted tissues are coming from stem cell reservoirs within those tissues, so they're still going to be "transplanted." It's not as if the tissue identity is going to slowly revert to the genotype of the transplant patient.


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

[User]
CMV: If you are anti-police, you cannot also be anti-gun ownership.

Due to recent police shootings and concerns about police violence why should citizens not be able to protect themselves? Short of a complete police reform, I dont see how people want the police to be the only ones with guns such as assault rifles.

Also, if the biden was to pass his proposed gun control measure, the $200 tax stamp would limit the ability of lower income people to protect themselves against police. This could effect people who fall into the lower income minority population, who arguably need protection the most against police and others.

As Fredrick Douglass said ,   "the liberties of the American people were dependent upon the ballot-box, the jury-box, and the cartridge-box; that without these no class of people could live and flourish in this country"

[Assistant]
>This could effect people who fall into the lower income minority population, who arguably need protection the most against police and others.

How do guns protect people in America from police?

Does Police see that the poor person has a gun and start acting kindly to him and don't do anything to him because he has guns?

Like is there any proof of anything like this and how does it work?


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

[User]
Why do microwaves damage circuitry?

More specifically, if microwave ovens use a frequency specifically chosen to resonate with the water molecules in foods, drinks, and whatever else if put in a microwave oven, why does it also have such a significant effects on certain metals and electronics?

[Assistant]
Microwaves, or any light for that matter, are oscillating EM fields.  In the case of MW its on the same size order of most of these objects so the fields couple very well.

These fields then induce a current which then proceeds to short or melt various parts of circuits.


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

[User]
CMV: I am convinced that certified doctors who prescribe homeopathic (alleged) medicine should have their job title revoked and be legally punished for scamming gullible people out of their money and probably their health.

Homeopathy is a pseudo science dating back to the time bacteria hadn't been discovered. There is not a single shred of evidence homeopathy works, except for the placebo effect.

Yet, doctors are allowed to claim that homeopathic remedies can cure a whole plethora of, if not all diseases and ailments. People who have serious problems often will believe anything anyone tells them in order to make their medical issues go away. A fortiori, this applies to people visiting certified doctors. The job of a doctor is essentially to be trustworthy.

I believe doctors have the moral and legal obligation to tell people homeopathy does not work, or at least has never in history been proven to work. If they don't do so, and cash in on prescribing horribly expensive bottles of water, they go against anything the medical profession stands for, in my view.

Does anyone have a radically different view here? If so, I would very much appreciate to hear it.

[Assistant]
Doctors don't need to prescribe anything to recommend it, and it will often have the same exact effects of influencing someone to purchase it.  So passing a law banning people from prescribing something won't actually take care of the problem with doctors who treat alternative medicine as medicine.  (How someone could actually get though medschool and take chemistry yet still believe in homeopathy baffles the mind though.)

You wouldn't really be able to just specifically target homeopathics because it would just lead other forms of alternative medicines to fill the gap.  Everything from chiropracty, to reiki and crystal therapy.   If you ban alternative medicine in general you actually ban some valid products.  For example Lovastatin is a heart disease and cholesterol drug that costs about 80-100$ a bottle.  The drug itself is isolated from red rice yeast and so for people who can't afford a preventative medication like that, a doctor will occasionally prescribe red rice yeast as an herbal supplement.  Yes it's an alternative treatment without FDA approval, but the active agents and the effects are constant.

In effect any law you could pass towards this end would not only fail to solve the problem it would also likely effect some legitimate treatment options.


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

[User] What is it about sleep that lets addicts not have to wake up to feed their habits? (I.E. Smoking, drinking, drugs, etc.)

[Assistant] In the case of physical dependence, they do wake up to feed habits. Its uncommon because typically, with physical dependence, they need it to fall asleep. Mental dependence just effects impulse centers of the brain which are largely dormant during sleep.


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

[User] ELI5: What does the vice president do?

[Assistant]
His most important job is to take over from the president if the president dies, gets too sick to work as president, quits, or is impeached (gets kicked out). This has happened a bunch of times throughout history, most recently in 1973 when president Richard Nixon resigned, making his vice president Gerald Ford president. This is one reason why its so important who the vice presidential candidate is--because they could become president at any time.

Another official job they have is to be a tiebreaking vote in the senate. The senate has 100 senators, so if 50 vote one way and 50 vote the other way, the vice president decides whether the bill passes or doesn't pass. He or she is not allowed to vote otherwise.

Besides those two jobs, he doesn't have many other official things to do. Sometimes he'll go out to other countries to talk with their leaders if the president is busy. Sometimes he'll go out and give speeches to support the president or his party's ideas. Sometimes he'll negotiate with people in congress on behalf of the president to get things passed. Some vice presidents have done a lot and worked really closely with their president, others haven't really done anything. It depends a lot on who they are and who the president is.

When the president is trying to get elected, they'll usually choose someone to run for vice president who will help them get elected in some way. For example, if people think the presidential candidate knows a lot about how to help make sure people have money and can find a job but doesn't know much about how to keep our country safe, they might choose someone to be VP who knows a lot about the military. They might also choose a VP who is really popular in an area of the country that doesn't like the presidential candidate very much.


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

[User] ELI5. Why is honey and lemon a popular cure for cold like symptoms. What makes lemon more effective than say an orange or lime?

[Assistant]
Any lighty acidic hot beverage with fructose (or sucrose) would cause the same effect of reducing coughing (most regular cough "medicine" is 99% sugar), so if you ran out of lemon you could try with apple cider vinegar, and honey can be really substituted with any other syrup.

Lime would be ok but most orange variants are heavily engineered towards sweetness in detriment of acidity, so not as effective.

A century ago, the original treatment on Europe was hot herbs/lemon liquors (diluted in water) and sweet wines, which also comes with a few extra "side effects".


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

[User]
[DC - Black Adam] How powerful is Dr. Fate in DCU compared to his longest running comic counterpart.

Just watched Black Adam and I'm a bit underwhelmed by Dr. Fate.

Dr. Fate in the Justice League cartoon series was a very powerful character.

Is the DCU version close to the comics Dr. Fate or is Dr. Fate's power level different because the JL cartoon and the movie had different personas? Or was he heavily nerfed in the movie?

I just remember Dr. Fate being God-like in the cartoon adaptation.

[Assistant] Dr. Fate is even more godlike in the comics.  That said, the DCU version was heavily holding back because of his visions of the future told him that that was the only way to win, turn Black Adam, and to make sure Hawkman survives.


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

[User] ELI5: New theory says that the Big Bang might not have happened?

[Assistant]
Fancy math applied to Einsteins original theories.  The paper, and the authors aren't like "hey, you are all wrong."  It's more of "hey, look at this model too."

In short, it's just another idea, that currently is not very accepted.  However that may change.  The bulk of the idea is that the universe is, and always was, and just because we see it expanding, does not mean it all comes back to a singularity.

Think of finding a not inflated balloon on the ground with knot in it.  While the evidence may suggest it deflated, it is also possible someone just tied a knot in the balloon and left it there.


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

[User]
[Lord of the Rings] Are all Dragons evil? Could a Good Dragon exist?

I'm sure this has been covered, so far as I recall the first Dragons were malevolent creatures. That being said, was there/could there (hypothetically) have been a "Good" Dragon, one aligned with Middle Earth against Morgoth and Sauron etc? Was Evil an intrinsic part of them?

Are they Evil in the same way the Orcs are, just totally twisted with sadism and cruelty worked into the very fiber of their beings? Explanations appreciated.

[Assistant] During the First Age, Morgoth knew that his orcs weren't sufficient against the host of the Noldor. Hence, using fire and sorcery, he created wyrms of great power. The first of dragons, Glaurung the Great Worm of Angband, the Golden, the Deceiver. It was Glaurung who orchestrated for the children of Huron to unknowingly marry one another. It was during the War of Wrath, that Morgoth revealed one of his greatest creations, the great winged wyrms, chief among which was Ancalagon the Black who broke the assault of the Hosts of Valinor until Earendil and the Eagles slew him on the slopes of Thangorodrim.


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

[User] What happens to the bones of whales when they die in the ocean?

[Assistant] There was a story on BBC's Blue Planet about exactly this. Essentially, it sinks to the ocean floor, where it becomes a beacon of life in an otherwise barren desert of lightless sand. Sharks are the first to feast, ripping off chunks of the carcass, while scavengers like crabs move in for the remainder. Many different types of life will feast on the remains for over a year, eventually leaving a completely clean skeleton on the ocean floor to eventually be ground to dust.


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

[User]
[Star Wars: The Force Awakens] (Spoilers) So, about the Republic...

When Hux is giving his big Hitler speech, he mentions something about that very day going down in history as the day the Republic died (paraphrased). Then, Starkiller Base proceeds to nuke the Hosnian system, where the current capital of the Republic was located. But simply destroying the capital wouldn't wipe out an entire nation, would it? The Republic probably had thousands, possibly millions of systems, but Hux was talking like they were about to completely obliterate the Republic, but there's no way that's possible.

If Washington, D.C. and its surrounding areas were completely nuked, the United States would go into chaos for a time, but there's no way the entire country would just collapse, right?

What do you guys think is the current state of the Republic?

[Assistant]
While they did not completely destroy the Republic, they wiped out the senate, and much of the government administration. Luckily the leadership of the Republic regularly moves between Hosnian Prime, Chandrila, and a few other places. So there would no doubt be some levels of the government intact.

Most likely it is a situation much like Battlestar Galactica, where a low level government figure is now the acting Chancellor.

The First Order's attack on the Republic was a serious declaration of war, which the Republic would simply be unable to answer militarily. The Republic de-militarized after the fall of the Empire.


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

[User]
Being added as a co-author without contributing to the actual research?

My advisor recently asked me to convert the formatting of a paper that was rejected from one journal to the formatting of the next journal they will be submitting it to. In exchange they have offered to add me as a co-author. I also created one part of a figure that appears in the paper, but that didn't require me to have any knowledge or understanding of the paper.

Normally I wouldn't have considered editing or figure art enough to deserve being a co-author. I'm slightly concerned about how it would make me look if someone asks what I contributed. The answer would have to be something like "not much, just some formatting of the final document".

Should I accept their offer and put my name on the paper?

[Assistant]
I think your contribution could easily add up to authorship depending on the norms of your field, and you are just coming in here with some imposter syndrome. Even if not, I'd take it as a "gift". Everybody else who you're competing against later in your career is playing the authorship game, you ought to too if you want a competitive CV.

Nobody is going to bamboozle you at a conference demanding you explain your contribution to a random paper of yours is. Even if someone does, you can simply answer "I made figure x and contributed to the drafting of the paper", and that's both perfectly true and in line with typical authorship guidelines.

To be honest, it looks almost more like your advisor is trying to help you by honestly getting your name on to some more papers rather than they just want to bribe you to do some bullshit reformatting.


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

[User] ELI5: Why does Hollywood continually cast people in who are 20+ to play teenagers?

[Assistant]
1) They're more experienced actors.

2) You don't have to worry about child labor laws, which makes working way easier.

3) They're probably better looking because they're fully grown, no longer get acne, etc.


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

[User]
[Logan] How is the Adamantium skeleton poisoning Wolverine?

After watching Logan, Ive seen Wolverine talk about how the Adamantium skeleton is poisoning him which worsens his healing factor, but how? Shouldnt his healing factor take care of the poisoning in the first place? And Wolverine lived for decades with it (He got the Adamantium skeleton back in 1970) and lived with no problem until 2023. After that year he started to age aggressively and become way weaker in the year 2029, all of that in just a span of 6 years?

[Assistant]
Metal poisoning works differently from other poisons. No matter how well you heal, you can't  metabolize metal. Some of it can be filtered out by your kidneys, but most of that metal will remain in your system, accumulating in your organs, and never leaving.

It's likely that the accumulation of Adamantium in his soft tissues didn't reach a level where it was actually toxic for a very long time, and once it did reach those levels, his HF had to work all the time just to keep up with the damage. As more accumulates, the less his healing can do to  counteract it, and eventually it overwhelms his healing Factor altogether, doing more damage faster than it can be healed, and leading to aging because his HF no longer has the spare resources to prevent it.


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

[User]
[avatar] How did Sozin Know?

"I knew the next Avatar would be born an Air Nomad, so I wiped out the air temples. But somehow, the new Avatar eluded me."--Sozin

So How did Sozin know he missed the Avatar? The FN's subsequent attacks on the Southern Water Tribe would seem to have been the natural confirmation that he had succeeded in destroying the airbender incarnation. What made him "know" that his mission failed?

[Assistant]
We're led to believe that they new Avatar is born immediately on the death of their predecessor, which Sozin personally witnessed. So he knows how old the Avatar is supposed to be. If no one goes into the Avatar state doing the genocide, then you round up all the eleven year old kids and go Darth Vader on 'em.

Really explains why Gyatso killed so many of the soldiers.


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

[User]
CMV: Modular smartphones are pointless.

Unless you can swap out the processor and the RAM, they seem to offer no advantage over a regular phone.

Magnetically attaching a speaker to the back of my phone is not better than connecting to a Bluetooth speaker. If I want a better camera Sony and Canon make wifi cameras that can interface directly with my existing phone or tablet. Those might be a little more expensive than a module but they're also way more versatile and can work with all my future phones and friends phones too as well as on their own.

It seems to me that all smartphones are wirelessly modular already, they just weren't marketed that way. For that reason the 'modular phone' that makes the most sense is actually the Pebble Core as it's just the processor, radio, and memory, to which you can add whatever you want to wirelessly (maybe not yet, but soon I'm sure).

Am I missing the advantage of physical attachment?

[Assistant]
Hardware failure. Critical component of your smartphone fails? That's a time-consuming hassle even if it can be fixed - just hope it's still under warranty - and if it can't, have fun buying and setting up a whole new phone.

Module fails? Take it out and replace it when you like. Much cheaper, minimum hassle.


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

[User]
CMV: The president has far too much power.

The purpose of the President, or the executive branch in general, is to execute the laws and bills passed by congress.
What that says to me, is that hes just here to make sure whats been decided gets done.
The power of the President to pardon people is absolutely appalling to me. We have a justice system, how can someone just decide that this person gets to bypass the system?
Another thing, executive orders. If their job is just to execute what was decided, why does an executive order have any power?
Please help me understand.

[Assistant]
>We have a justice system, how can someone just decide that this person gets to bypass the system?

Pardons are a check on the power of the Judiciary. If someone or some group does not have the ability to grant pardons, the Judiciary has no check on their ability to interpret laws. The pardon is meant to bypass the system if the system is bringing about wrong outcomes. There are certainly arguments against the president having pardon powers, but it would be immoral for no pardon powers to exist.

>Another thing, executive orders. If their job is just to execute what was decided, why does an executive order have any power?

Executive orders are directives that clarify laws passed by the legislature that were vague or unclear. An executive order that does not have constitutional or statutory backing can and will be thrown out by the Judiciary. Laws can be very vague or intentionally leave implementation details to the Executive branch. Executive orders just tell the Executive branch how to execute the legislation that has been passes.


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

[User] ELI5:Why is it that when flies land on our LCD/LED screens, they don't get affected when we move windows or make some rapid movement which results in some colour change in the screen?

[Assistant]
Fly fear responses are based mostly on air currents and visual stimuli from above the fly, because that's where predatory threats come from.    They don't have much in the way of general intelligence, and escape responses are hardwired so they can be faster, so random visual stimuli from unexpected directions don't really register.

If you want to see something funny, though, put a little jumping spider on a computer screen.  It _will_ follow the cursor around like a cat after a laser pointer, because jumping spiders are incredibly visual and keyed to look for prey running around on surfaces.


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

[User]
[Marvel/DC] How does a speedster go downwards or down stairs at super-speed?

When a normal person goes down a flight of stairs they are allowing their body to fall to the next step at 9.8 metres per second per second. So a speedster shouldn't be able to go in a downwards direction faster than gravity. How do people like Quicksilver overcome this? NO SPEEDFORCE PLEASE!

[Assistant]
Speedsters can run down stairs the same way they can run up or across walls- their capacity to propel themselves creates greater force than gravity, and they are able to move to their next step (and continue propelling themselves) before gravity takes effect between actions.

A speedster running down stairs wouldn't go down stairs the way we do, which is essentially a controlled fall. They'd position themselves in such a way that they are literally propelling themselves downwards, faster than gravity.


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

[User] ELI5: Why do women soccer players "fake fall" so much less than the men?

[Assistant]
The real reason is that diving is cultural and the countries that are successful in the women's game don't dive as much.

The women's game is dominated by USA/Canada, Asia, Northern Europe. The one exception is Brazil and they dive the most of the successful women's teams.

Latin American and Southern European teams are known for diving and they are not good. But that is offensive to say so instead we'll pretend its something else.


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

[User]
ELI5: How do physicists shoot beams of small particles, like electrons, protons, and neutrons?

On occasion, when reading about some experiment, say the dual slit experiment, I'll read that a beam of electrons are fired at the slits. How exactly does one do this? I'm assuming you can't just go out, buy some, and stick them in a gun.

[Assistant]
Electrons are easy; they're the social butterflies of the subatomic realm. They flit about very promiscuously. And because they have electric charge, they're easy to manipulate with electric fields.

The general process by which electron beams are created involves passing an electric current (which is a flow of electrons, essentially) through some kind of conductor that, when it gets hot, sprays electrons out. This phenomenon is called *thermionic emission,* and it generally means that the *thermal* energy of the electrons exceeds the *binding* energy of the electrons, so they escape from whatever material you're using.

Once the electrons get sprayed out of the hot cathode, their trajectories are "bent" by the presence of electric fields. The spray is therefore shaped into a collimated beam.

Proton beams are a bit more complicated, because protons don't come flying off of hot things the way electrons do. Generally the way proton beams are created is by taking hydrogen gas which is just protons with electrons clinging to them and stripping off the electrons with a strong electric field. Electrons are very light particles compared to protons, so it's possible to yank them away and send the protons shooting off in the opposite direction. From there, it's the same story: Shape the spray of protons with electric fields to create a beam.

Neutrons are even more complicated. They're electrically neutral, which means we can't touch them  literally. There's no way for you to accelerate a neutron. Instead, they have to be *made* by knocking hydrogen atoms together. Most hydrogen atoms contain just a single proton and a single electron, but some  called deuterium have a neutron in there as well. If you smack two deuterium atoms together in the right way, they glomp together to make a helium atom, and eject the extra neutron. Do this in a very precise fashion, and you can create a beam of neutrons shooting out of a piece of metal. You can't control the beam the way you can with electrons or protons, because again, neutrons have no electric charge and can't be touched. But you get a beam nonetheless, which you can point at things to make a wide variety of interesting things happen.


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

[User]
The universe is said to be around 23% dark matter, 72% dark energy and 5% ordinary matter. If we don't know what dark matter and dark energy are, where do the percentages come from?

Edit: I just want to clarify, I'm aware of what dark matter and dark energy are. I'm by no means an expert, but I do have a basic idea. I'm wondering specifically how we got those particular numbers for them.

[Assistant]
We can calculate things like gravity and energy density of the universe base on how the galaxies behave on a cosmic scale.  We can also calculate how much stuff is out there by direct observation.  When we look at the cosmos and look at how the galaxies behave, there is not enough material to generate the gravity (even when accounting for all the gas and dust that may obscuring it).  So there's some matter that doesn't emit light but still generates that gravity we see.  We call it dark matter, because that's what it is: dark.

There's also an expansion to the universe that suggests that the energy density is not what we can directly measure.  There's a bunch of stuff out there causing the universe to expand at an accelerated rate.  We call it dark energy, because, hey, we have dark matter already--why not call it "Dark Energy"; that way it sounds cool.

So there's like 5 times as much matter as what we can see, and like 3 times as much energy density as what can be explained by that matter.  So that's where the percentages come from: just add up all the stuff we know about that makes up the universe even if we don't yet know what that stuff is.


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

[User]
Is it possible to receive so many vaccines that you "run out" of Memory B cells?

I know that vaccines work by memory B cells storing the antibodies for different diseases, but is it possible for them to reach some sort of saturation point? It's probably not anywhere near a practical number of vaccines, but is that how it would work?

[Assistant]
We have a huge amount of B cells and each reacts to a different antigen ( the part of the protein,microbe or other types of molecules that it recognizes) , when one of them is stimulated by its counterpart it reproduces, creating new B cells that react to that particular antigen, but the other B cells that weren't stimulated don't reproduce, they just stay in their "unactivated" state.
So the short answer would be no.
Hope i helped you,mif you have any mire questions you can PM me.


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

[User] ELI5: What did Nixon supposedly have to gain from the Watergate Scandal? Wasn't the Democratic Party already imploding as a result of McGovern's failing Presidential campaign?

[Assistant]
Nixon didn't order the Watergate break-ins or know about them until after the fact.  So they weren't part of an overarching strategy of his.

The reason he ultimately resigned is that once the burglars were caught, he tried to cover up the involvement of White House staff.


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

[User]
How can I see satellites at night?

The title. How can I with my bare eyes see satellites fly by at night? Is it the sun's reflection that I see or are the satellites equipped with their own lights?

edit: Ok. I wasn't really clear. I've seen the satellites at night and what I'm asking is how it is POSSIBLE to see them with my bare eyes.

[Assistant] You are seeing reflected light. You'all also notice that the intensity of the light goes cyclically up and down; the rate at which the albedo changes is the rate at which the satellite spins around it's axis.