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

[User]
[Silence of the Lambs] Could Hannibal ever be rehabilitated?

Let's say you had an unlimited budget, and treated him like an anomaly.

Here's this psychologist that murdered a ton of people.

Could he ever be returned to society if there were the world's best psychologists and such on team to try and re-educate him?

[Assistant] Not possible.  He's a complete sociopath with a brain incapable of empathy. Try all you want to rehabilitate him but he's too far gone to ever develop the needed mental state to no longer be a danger.  He'd be better off locked away for case studies or executed for his crimes with his brain donated to medical research.  Last I'd heard severe sociopaths could be trained to associate punishment for not feigning empathy in children and adolescents but in adults the treatment has a much higher failure rate. Lecter would be able to resist any treatment or understand it enough to manipulate it in his favor to appear like its working.  He's simply too intelligent and too far gone for any hope of meaningful recovery.  He knows he can get away with his crimes and has no fear of punishment so he'll do whatever he has to do in order to free himself to indulge in his habits once again.


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

[User] ELI5, why does clay harden when heated instead of melting?

[Assistant] Clay that can be easily sculpted is a bunch of extremely small rock/earth particles mixed with some water. The layer of water between all the particles helps them stick together even when you push and sculpt them. When a clay object dries out, you end up with particles which are just resting in a big pile without any water to hold them together, which is why air dried clay is really easy to break - there's nothing holding the particles together. During the firing process in a kiln, all the little particles in the clay fuse together (the easiest way to picture this is a bunch of spheres melting just a bit on their outer surface and then all those molten surfaces  sticking together).


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

[User]
ELI5: Why do my cheerios make a "crackling" sound in my milk?

Is this, like, the milk being absorbed or what?

[Assistant]
When you pour milk into your bowl, the cereal absorbs the milk. As milk flows into the crispy kernel, the liquid puts pressure on the air inside and pushes it around.

The air shoves against each pockets walls until they shatter, forcing out a snap, or a crackle, or, as you, know, sometimes a pop.


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

[User]
How does Superman find his way back to Earth after a visit to interstellar space?

Does he simply see Earth from such distances with the naked eye, or does he just have a superhuman sense of direction? Question also applies to other superpowered beings capable of unassisted spaceflight.

[Assistant] With how closely Superman is tied to sunlight, and how different stars effect him differently, he can likely tell stars apart as easily as we can tell flavors apart. To Supes Alpha Centari looks as different from Sol as we find strawberries a different flavor from raspberries.


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

[User]
[Monsters Inc.] Why was Monsters Inc. under investigation by the CDA?

I assume that the CDA would need a pretty good reason to investigate Monsters Inc.  Not only did they conduct an undercover operation, but the **head of the agency** was installed as the undercover agent.  This would be akin to the head of the SEC (someone fairly well-known) taking a job at JP Morgan Chase.

[Assistant]
Probably the fact that Waternoose, the company's chairman, was working on a plan to kidnap children (who are known to be **highly toxic**) and bring them **into** the world.
It's the equivalent of the head of an energy company having unprotected radio-active material in his office.


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

[User] ELI5:Why doesn't Youtube have an option to turn off video streaming and become the largest audio streaming site?

[Assistant] The main reason that you get that "you can't watch this shit on mobile" is because content providers don't want YouTube being used as an all-day audio streaming site.  They only want fully-engaged users watching videos.


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

[User]
[Sonic The Hedgehog] Where do artificial hypothetically man made objects like springs and dash panels come from?

This always has puzzled me when it comes to Sonic games, and I cant find any answers anywhere else, so I figured Id ask here.

The Sonic franchise is home to many different locals. Some of these are ancient, mostly untouched places, like temples, forests and the like. My question is this. Why, in an ancient temple, is there a modern dash panel, designed solely for increasing speed during gameplay, in a place where such objects should not be present.

I can accept this in more modern set levels, like Radical Highway, where due to a percentage of the population being anthropomorphic animals who are able to use peripherals like these, it makes sense for the government of the Sonic universe to install these devices. However, it doesnt make sense when the randomly appear in otherwise completely natural spaces.

Any insight would be appreciated :)

[Assistant]
They are put there by Dr Eggman.

The powerups aren't meant for Sonic's use, they are meant for his own minions. They are placed in hard to reach places or hidden, and the springs are meant to help them get there or traverse loops, otherwise most of the zone would be impassable to them.

Why don't they use them then? Because they are slow, Sonic can easily zip through an entire zone in less than a minute. While Dr Eggman's minions are powerful enough to one-shot Sonic (without rings), they are usually too slow, but it generally isn't their main purpose, they are meant to control an area, Sonic also tends to skip them if they aren't a direct threat (to go faster). Dr Eggman fights Sonic personally with more advanced robots and when he controls the battlefield.


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

[User] [Batman] Dear doctors, what mental disease does Joker suffer from?

[Assistant]
Depending on who you ask, and when you ask them: all of them or none of them.

The man might be little more than a lumbering, human-shaped stack of insanity, held together by duct tape, makeup, and countless years of trauma.

*or*

the Joker could be playing the world's worst madman as the world's best actor - capable of continually and convincingly fooling the Greatest Detective himself.

The motive of his madness, if it even exists at all, is likely as indescribable and capricious as the man himself. Trying to get an accurate prognosis of the Joker - where the freakin' Batman has failed - would be harder than squeezing blood from a rock. Of course, nobody's ever gotten a straight answer from the Clown Prince of Crime regarding his mind - the last person to do that turned into his girlfriend (*shudders*) - but you are more than welcome to pick his brain and become the latest in a long and unbroken line of tragedies.


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

[User]
[MCU] Thor is said to be in his 1500s, while Loki is around 1000. What is the ageing rate of Asgardians, especially when they appeared a similar age in a flashback?

Thor has at least 500 years on Loki, yet the flashback in 'Thor' shows that the former appears only slightly older than the latter.

Do Asgardians age at an approximately human rate initially, before it slows down significantly, or is their overall ageing much slower? Does Loki being a frost giant mean a different rate of ageing?

[Assistant]
In the comics, Asgardians age about 1 per 100 years - with Thor being around 3000 (30) years old, having been around 2000 (20) years old during the Viking Era. but that doesnt seem to work for the MCU.

I think Frost Giants age around the same rate - or at least Ymir, the leader of the Frost Giants, is easily as old as Odin.


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

[User]
Is it just me or is a PhD like this?

Honestly, the phd itself doesnt seem difficult coursework wise, but its honestly figuring out how youre being in this thing and not letting anxiety issues overcome you and people and politics that seem to govern the trade.

More so than actual ability to do research although in a department of repute your actual ability will count for something.

I am sweating over the lit review and the data set of missing data right now, but the project I was on before honestly doesnt seem that hard.

Its the research thats the hard part.

Am I overthinking this?

[Assistant]
The PhD is about learning how to independently conduct cutting-edge research.  The courses are meant to help you know what the cutting-edge is, and at least give you the background on how to design a study - but implementing and completing the actual research is pretty much what the degree is about.

So yeah, the research is the hard part - and as you've noted, it's not necessarily that it is challenging to physically accomplish (in the way that say, pole-vaulting a 19 meter bar is), but it is something that requires persistence/motivation, careful attention to detail, and creative ability to problem-solve challenges and unexpected issues when they arise.  Only like 50% of folks who start a PhD ever finish it, and very rarely is it the coursework that causes people to drop out.  Usually, it is once folks have moved on to the dissertation, and find themselves with no "known" answers, no deadlines, and just a problem that they are trying to solve - for students who spent the previous several years of their academic career memorizing facts and performing well on projects and tests that can be a horribly uncomfortable (and anxiety-inducing) experience.

Research is absolutely the hard part.


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

[User]
Explain like I'm five: Cold Fusion

What is cold fusion? How does it work and how would it be used practically?

[Assistant]
Imagine you have two balls. These balls really don't want to touch each other but if you put a lot of energy into forcing them to, they explode releasing tons of energy.

This is called nuclear fusion.  The balls are certain atoms and the energy is usually extremely high temperatures(millions of degrees). Instead of making the two atoms touch you are combining them into one larger atom. This process is what the sun is doing to create all of its energy.

Cold fusion is the term for a Nuclear Fusion reaction that can be done at a relatively cooler temperature and other conditions that we can create on earth. Currently there is no cold fusion technique that produces more energy than what is required to sustain the reaction.


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

[User]
[Star Wars] Can C3PO speak Shyriiwook?

I was thinking about Chewbacca and C3PO just and I thought it would sound hilarious if C3PO spoke Shyriiwook in his voice.

So is that one of 6 million forms of communication he can speak?

[Assistant]
Yes.  He understands it, he has a voice synthesizer and isn't limited by biology, so logically he can speak it.

He doesn't use it with Chewie, though, because Chewie understands Basic just as well, and C3PO prefers to use Basic if his conversation partner understands it (e.g. conversing with R2D2).


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

[User]
ELI5: Why is owning 5% of a company such a big deal for hostile takeovers?

I've seen on a few shows now (Suits, Billions) that owning 5% percent of a company is a huge first step in taking over/making a tender offer for a company. Why is this such an important milestone?

[Assistant] Anyone who owns 5% of a public company has to register a schedule 13D with the SEC, which means their ownership is now public knowledge.  If you plan a hostile takeover the element of surprise is over when you cross the 5% mark.


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

[User] What are some legitimate controversies/problems with the big bang theory?

[Assistant] nothing significant enough to make us think it didn't happen. What we don't yet know is the behaviour of space-time in the very very early universe (<10^-15 seconds or earlier) because at some point, we need both GR and Quantum Field theory to be compatible to describe that state. Also unknown, exactly what was inflation? Exactly what is dark energy?


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

[User] ELI5: Why is it more difficult to run for long periods of time when exercises like biking are just as strenuous?

[Assistant]
It's all about practice. You use different muscle groups for different kinds of exercise.

Running is *really* hard on your body. You're obviously using your leg muscles, but you're using a whole bunch of other muscles that you may not be aware of. Abs, arms, back, neck, they all play into it with running.

Bicycling, you're sitting down, for one. You can also stop peddling for a bit. And you have different gears. Not to diminish from cycling, but it's not really as strenuous as running.


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

[User] eli5 Why do fruit trees grow naturally in the wild while home grown fruit trees take so much care and effort?

[Assistant] It depends where you live. If you live in the Northeast or the northwest, you can easily grow apple trees in your yard. If you live in the southeast, especially Florida, citrus and avocado will grow wild. But if you live in Minnesota, you ain't growing oranges, and if you live in Texas, you ain't growing apples.  So if you want fruit trees to grow in your yard without a lot of effort, you've got to pick ones that are native to your area or at least growing similar climates.


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

[User] [Mandalorian] How do chaincodes work and what do they do? Who makes the chaincode for each bounty?

[Assistant] Chaincodes are most likely a form of identification. Similar to a block chain on crypto currency they identify the people involved to some degree so bounties can be tracked and payments rendered appropriately.  Also may be some form of unique identifier similar to a social security number assigned to people through a communication network. Allows a bounty hunter to specifically target the exact person they're after due to likely DNA tracking tied to the chaincode number. How it can be used to track someone from orbit and fit in a tiny device is beyond me however.


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

[User] ELI5: why hasn't there been an uprising in North Korea?

[Assistant]
I believe the biggest reason is an astonishing lack of global awareness and comprehension of the oppressive government.

I believe if the citizens were suddenly given access to open and accurate information they would revolt quickly and successfully. The elite could not hold back the entire citizenry, which is why the people are kept so uninformed.


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

[User]
ELI5: Are music tastes completely personal or does our environment play a role on them?

Do friends shape what we listen to? Are we born with certain music tastes?

[Assistant]
Nature or nurture? It's both. Your environment can definitely play a role!

1. You like what you hear around you. This is how music is passed down in certain cultures. Like how Indian people like Indian music. Or if your mom is a classical pianist and played piano all the time, you probably have a higher chance of liking classical music.

2. You like music that speaks to you and that you can connect with emotionally. Maybe you like hip hop because your environment made you poor and now you're working really hard to "get yours" so the lyrics in hip hop songs are meaningful to you.


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

[User]
[Fallout]What do the East Coast super mutants want?

Why are they loyal to super mutant-kind as a united front against humanity instead of retaining the loyalties they had as humans?  Why do the ones in DC abduct humans and create more of themselves?  Why do they talk about being the 'future'?

All of this is explainable in the west by the influence of The Master, but no such figure seems to exist in the east.  So what does motivate the mutants of the east to act the way they do?

[Assistant]
The east-coast brand FEV seems to be far more volatile towards the minds of its subjects, hence the insane screaming and constant need to decorate with viscera. They aren't really *loyal* to super mutant kind, as much as they're the only things they don't mutilate or mutate.

As for the whole 'future' spiel and their insistence on sustaining the mutant race, it was probably the first information given to them. Again, the old personality and memories just got obliterated, and now they need a purpose, a goal. Seeing as the Vault 87 personnel were connected to Mariposa, it's not hard to assume they had a similar view of the FEV as a potential method of saving humanity.

With that goal in mind, the mutants go out in search of more FEV and people to use it on, because it's the only thing that makes sense to them now.


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

[User]
ELI5: why don't Italians speak latin?

What happened to latin? Surely if the centre of the Roman empire was in Italy they would still speak latin today!?

[Assistant]
All languages evolve over time. The Latin language spread out and, as languages do, evolved in different ways in different areas to give us the modern Romance languages Italian, French, Spanish, Portuguese and so on.

Even when Latin was still being spoken as Latin, it changed from one generation to the next. The early Romans spoke Old Latin, which evolved into the Classical Latin which is what we usually think of as "Latin", and which went through many changes over its lifetime; changes continued throughout the Mediaeval period and the Renaissance.

Latin is still spoken in the Vatican, of course, which is in Rome, and has the world's only ATM that can display instructions in Latin. But it's not the same Latin the Romans spoke: it's a later version, Ecclesiatical Latin.

All these versions of Latin were those spoken by the educated people. Ordinary people spoke vulgar Latin ("vulgar" simply means "of the people" and doesn't mean "obscene"), which again varied from place to place and through the generations -- just as most of us today speak a version of English that you wouldn't expect to hear the US President use in his State of the Union address.

And there is one version of this vulgar Latin that has survived to this day. Well, in truth, many of them did and are now French, Italian, Spanish, etc., but this one is much, much more closely related to actual Latin than any of the others, including Italian. It's a language called Ladin, spoken in remote communities in the mountains of northern Italy. So if you want to know what happened to Latin, apart from the slightly artificial version used by the Church, it still exists and is spoken by about 30,000 people. Cicero, however, would not be able to understand a word.


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

[User]
Can rainfall amplify sky noise? (Jet noise more specifically)

Raining in Ohio now. Hearing jets noticeably louder than on clear nights. Not near low or varied flight paths. Wondering if pressure or downward movement of rain is somehow at play.

[Assistant] It's mainly acoustic reflections off the clouds (which is mainly due to particles and temperature gradients within the cloud). You should hear the same on a cloudy (but dry) day as on a rainy day with comparable cloud cover.


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

[User]
ELI5: How is it that clothes ALWAYS produce more lint?

It just blows my mind that no matter how many times I wash my clothes I always have to clean the lint trap afterwards. My little ape brain wants to believe that there is a finite amount of lint that can shed from clothes but Im willing to be proven wrong!

[Assistant] "lint" is not just one specific thing. Lint is made up of many different things that get stuck to the fibers in your clothes and also the fibers of the clothes themselves. Every time you wear your clothes you accumulate more lint. That's why there is always lint.


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

[User]
CMV: Community Colleges should be allowed to offer 4-year degrees.

Before I transferred to college, I was at a community college for four years. I completed all my lower division general education classes and received an A.A in Communication studies. I feel that I have completed enough college courses to have already received a 4-year degree. The courses I am enrolled in now at my university for Communication Studies are very similar in difficulty and subject matter. Although I do enjoy my classes at the university, it feels somewhat redundant.

Since many of us have come to understand that a Masters degree is the new Bachelors degree, I feel it makes sense to offer 4-year degrees in community colleges. This would save time because the degree would be completed sooner as is my case, and it would save money because community colleges are generally cheaper than universities. I do not want to blend community colleges and universities, because community college offers benefits that universities do not such as accepting all those willing to enroll and tuition is cheaper. Therefore, instead of change the current university system, community colleges should offer 4-year degrees.

[Assistant]
If they offered a 4-year degree, they wouldn't be community colleges anymore.  They'd be universities, and they'd cost as much as universities.

That's what separates the two.  It's why community college is cheaper.  Because it's a stepping stone that doesn't have to go through all the stuff it takes to offer a four-year degree.

This is like saying that McDonald's should serve filet mignon, but still be $3.


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

[User] ELI5: How did countries control their borders hundreds of years ago?

[Assistant]
Patrolling militaries.

You had a lot of natural borders such as rivers, mountain ranges, ridges, forests, etc. And the travel points over, through and between each of these would be garrisoned with a fort and soldiers.

These soldiers would control who goes in and out and keep the borders.

If this fort was taken by an enemy, then that entire area would become the enemies and could be a staging ground for a major invasion.


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

[User] [Back to the Future] When Marty returns to 1985, he arrives right when his other self is going to 1955. But the Marty escaping has grown up in the timeline where his parents are successful. So how different would that Martys experience be like in 1955 versus what we saw?

[Assistant]
he will go back and safely wait out the week at doc's place and not interact with anyone else at all in order to preserve the timeline (a more sensible and well thought out attitude - this difference in behaviour comes as a result of growing up with parents that aren't losers). thus he unwittingly creates the original loser-parents timeline through his lack of interference. in this way there is a constant oscillation between the two timelines, or more accurately there are simply two branching timelines (as far as this question is concerned): loser-parents timeline and cool-parents timeline. the native martys switch timelines, each generating the other and returning home to the other's home timeline.

in short, the loser-parents marty's interference causes the cool-parents timeline, the cool-parents marty's noninterference causes the loser-parents timeline, the two martys switch lives.


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

[User]
[Harry Potter] How has the magical community managed to keep up the masquerade this long?

Sure, there have been a couple slip-ups (Salem comes to mind), but for the most part, there have been no major leaks or anything. How does the community stop random trolls from spilling the beans? Extremist groups who have tons of evidence ready for Muggle media? Various dark lords who would seek to take over the magical *and* Muggle world? With all its faults, is the Ministry just *that* good at memory-wiping every single non-related Muggle who finds proof of magic?

[Assistant]
1. **Wiping memories.** Wizards do a lot of this. *Obliviate* and False Memory Charms are the two biggest tools there.
2. **Crime scene clean up.** Magic like a mending spell allows a wizard to clean up a trashed breakfast nook almost instantly. Healing spells can fairly easily patch up a person who's had their legs broken.
2. **Unplottability and Disillusionment.** Wizards have magic that turns people away places that they're not allowed to see, and magic that makes them unable to see it. It's debatable whether a muggle could even *see* a troll - we know for a fact that they can't see (only sense) Dementors.
2. **Bias against the unnatural.** Oh, so you have a shaky home video movie of someone flying through the air? Well, it's probably a prank or a hoax. You don't have a video? You're probably insane, or mistaken about what you saw.
3. **Worldwide organization.** It's not just the British wizards - it's every wizarding government in the world working in harmony. They also have a multitude of fast travel methods. Wizards also have some level of buy-in from muggle governments.
4. **Small population.** There just aren't that many wizards. In the muggle world, it makes sense to talk about an extremist group forming from the millions of people, but the population of magical Britain is tiny, and the same goes for the rest of the world. Extremists are less extreme, and less likely to find co-conspirators.
18. **Time period.** At the time the books take place, there's no internet, no quick video sharing, and home video itself had only been around for a limited amount of time. That leaves definitive proof much harder to come by and much harder to share.

That said, there are a few documented cases of wizards trying to break the masquerade, but none have been successful, mostly because of their Ministry's wide-reaching powers (and partially the ineptitude of these crusaders).


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

[User] [Genies] Are Genies required by some cosmic force to put a sinister twist on wishes, or do they do it for their own entertainment?

[Assistant]
Lets say you're a, near as it matters, all powerful elemental that hangs out in the arabian deserts. Your omnipotence means that nothing is particularly interesting except free-will so you spend your time legitimatly offering kingdoms\riches etc to mortals just to see what impact they'll have or  how quickly they drive themselves to despair.

One afternoon you take a rest for a bit only to wake up contained, bound and limited to using your power solely to aid the smug git that caught you napping.  Time to get your smite on... except you can't so you just grant wishes with a side dish of delicious irony.

A few masters down the line and it feels like old times except instead of tempting the poor sods to act as your playthings they come to you and demand it.   Let the good times roll.


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

[User]
Why are songs typically about 3.5 minutes long?

Edit: Woah this got popular. Thanks for the answers :)

[Assistant]
Short answer: Because it just feels right.

Long answer: Because we've been conditioned by years of pop radio to believe this is the perfect song length, any longer and we'd start to get bored of it; any shorter and it'd feel like we'd been robbed. It's a largely arbitrary length born in the radio age that allows us to flesh out the song in a pretty full manner, while not boring the listener nor inviting them to switch to another station.


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

[User]
What is gas-liquid mass transfer in the context of bubbles?

Hi there, I am doing some research on micro bubbling technology used in water-treatment. One term that comes across very frequently is gas-liquid mass transfer. Right now, my interpretation of this term is the rate at which gas in the bubble dissolves and transfers to the liquid or the water body. Is this accurate? I am struggling to find a simple to understand explanation of the term through goggle searches.

[Assistant]
yeah. That's pretty much it. Gas is going to be a high purity gas such as Oxygen, CO2, Ozone or Nitrogren. Air, is of course a gas mixture.

So mass transfer is basically how many Kg of the gas pass into the liquid when you put the gas and liquid together in a mixing apparatus. In this case the mixing apparatus is basically a water basin or pipeline with your microbubble diffusers.

Mass transfer is often expressed in terms of efficiency: what % of the gas actually made it into the fluid when you mix it. Or in terms of mass transfer rate, in mass unit of the gas per unit time.

Both metrics are useful: the first metric helps you to dimension transfer equipment but also tells you the gas loss you are going to experience in the process, this is important because money.

The second metric is useful if you know that your gas consumption after transfer will be. For example, if you have an activated sludge that consumes 10 kg per hour of oxygen, you know you need to a transfer device that can transfer 10 kg per hour of oxygen.


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

[User]
[Wallace and Gromit] Has Wallace tried to make cheese?

In *A Grand Day Out*, we see he is dedicated enough to cheese that he builds a rocket ship to get more. In *A Matter of Loaf and Death* he's running a bakery business; while cheese making is different from baking, it shows that he isn't inept at cooking in general. So why hasn't he tried going into the cheese business, or at least make cheese as a side hobby?

[Assistant]
Wallace is an inventor and he's impatient.  It's easier for him to build a space-capable rocket with hand tools in an afternoon than it is for him to wait a few months for cheese to age properly.

Also, it's harder to get the kind of variety he's accustomed to by making his own.  There are so many kinds available commercially that it would severely limit his options making only a handful of types.


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

[User]
Why does the U.S. export F-35's, but not F-22's?

They won't export any F-22's, but they will export F-35's.  Why is that?

[Assistant]
the top rated post does a great job on the details, but this is ELI5, so here goes:

When countries (the US excluded) are buying planes for their military, they want to spend as little as possible while doing as much as possible. A multi-role fighter like the F-35 suits many missions and requires less support to deploy. The only countries with the support necessary to deploy a dedicated air-superiority fighter like the F-22 already have their own in development.


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

[User]
[General Sci-fi] Is there any technology on modern earth, that an FTL capable species might plausibly lack?

What are the odds that if aliens showed up tomorrow, our technology would surpass there's in some minor way?

[Assistant]
In the Uplift Wars universe, humanity is a "wolfing" race.  We bootstrapped ourselves to space and sentience, unlike every other species in the community.

In most areas human tech is eclipsed by galactic tech.  Humans have an edge in a couple areas:

Human holograms are top of the line, and can fool other species.

Humans were trapped on Earth for so long that we've become exceptional at ecological rehabilitation.

Also, we invented a device called a cooling laser, which takes heat from the surrounding environment and converts it to a powerful laser.

The reason humanity was able to develop these technologies is that the galactic community is stagnant and highly resistant to change or innovation that might upset existing political power structures.


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

[User] ELI5: I know resonance is when you vibrate something at its natural frequency and so it vibrates more, but what is a natural frequency and why do different things have different natural frequencies?

[Assistant]
Clap. Now smack your chest. Now slap your butt.

All different sounds, right? That's bc they are built differently. Your hands have little muscle, and many bones, the sound will be high pitched (high resonance frecuency), your chest will sound more like a deep bass. It has bigger bones than your hands and a huge empty space bc of the lungs. And your butt will be a midground, bc it's mostly muscle and fat.

The frecuency (sound) a material or objet has and resonates at depends on a lot of factors. Tension, material, hardness, mass, thickness, weight.

The best way to picture this is simply grabbing a guitar. Thin cords are high pitched, thick cords are low pitched. And you can modify the pitch by adding tension.


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

[User]
University stopped subscribing to Summon Search. How can I use my university credentials to access articles I find through Google Scholar?

I used to find the Summon search very convenient as you can filter articles by author names, and much more. It has been replaced by EBSCO, which in my opinion is not as effective. I can search for journals and articles using Scholar but I cannot access it as I can only use my university credentials. Is there a way to do this? University staff has said I've got to use EBSCO and it's really bugging me.

[Assistant]
In the upper right corner of the Google Scholar homepage, you'll see a little gear. Click on that to get to the setting page. About halfway down, you'll see "Library Links". Type in the name of your school and your library's citation linker should come up. Check it off and hit save. Now you should have links to full text in your Google Scholar results.

If this doesn't work, then talk to your library. They need to contact Google to get it set up.


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

[User]
ELI5: When a tub of ice cream melts and becomes liquid, why is it ruined even after you freeze it back again?

When you freeze the ice cream after it melts from store bought and becomes completely liquid, it doesnt stay the same way.  It just isnt ice cream anymore, theres no cream, it becomes like frozen ice lolly kinda texture; completely different from the texture it comes in ie. Soft, fluffy, milky, creamy.

[Assistant] When you make ice cream it is churned constantly while it freezes. Ice cream makers also have blades that scrape the ice off the inside walls of the vessel since that freezes first. Keeping all the ice cream moving like this as it freezes keeps the ice crystals that form very small. The small ice crystals is what gives fresh ice cream that smooth texture.  When the ice cream has melted and is then refrozen you get much larger ice crystals, which is why it kinda has the texture of a bad snow cone now.


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

[User] ELI5: Why do we squint our eyes when we try to listen/hear something that is difficult to hear?

[Assistant] I believe it is related to us subconsciously trying to increase our ability to focus on the incoming signal of the sound by blocking out some of the other sensing signal noise e.g. Vision. So by squinting, we reduce the visual signals to our brain and it is better able to focus on the audio input aspects. Much like how you hear some blind people developing almost supernatural  other senses, but on a much smaller and immediate scale.


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

[User] [Star trek] If a person is killed by a hologram in a holodeck due to failed safety protocols, who is legally at fault?

[Assistant] Safety protocols on a Federation ship can only be overridden by an officer with high security clearance, otherwise a failsafe activates and the program is terminated. In the event of a death caused by a holocharacter the officer(s) that disabled the safeties is/are responsible. In a holosuite it would be the proprietor at fault.


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

[User] ELI5 Why do so many people get their wisdom teeth removed nowadays as opposed to ancient times? What changed?

[Assistant]
Long story short, our hunter-gatherer ancestors had stronger and larger jaws, as their diet - raw flesh, plant roots, etc. - required much more chewing than our modern diet does.

As our jaws grew smaller, the total amount of teeth they were supposed to house sadly did not, causing the originally useful wisdom teeth to become a serious issue for many people.


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

[User]
Why is g++ saying my header file does not exist?

I am trying to use g++ to compile a program that uses header files I created in the same directory as the .cpp file. The cpp file is titled "pgm2.cpp" and the header file is "cardDeck.h." I have made sure to add #include <cardDeck.h> to the cpp file, but when I run the command "g++ pgm2.cpp" I get the following error:

    pgm2.cpp:12:10: fatal error: cardDeck.h: No such file or directory
       12 | #include <cardDeck.h>
          |          ^~~~~~~~~~~~
    compilation terminated.

Is there any reason why this is happening?

EDIT: Found my issue. Should've used quotes instead of angled brackets, so my include line should have been #include "cardDeck.h"

[Assistant]
Including a file with angle brackets tells the preprocessor to look for that file in the system include path, or in directories specified with the -I directive when invoking the compiler.  This does not search the local directory unless you have asked for the local directory to be searched with `-I .` or equivalent.

That's what you'd use to include system headers like <vector> or <iostream>, but shouldn't be used for user defined headers like cardDeck.h.  For that you should use quotes, which first searches the local directory and then goes on to search all the places that including via angle brackets would have.

Note that this behavior is not specified in the standards--both `#include <filename>` and `#include "filename"` search in an implementation defined manner.  This answer is specific to g++, though it's a common design decision on how to interpret angle brackets versus quotes.  At a minimum clang has the same behavior.


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

[User]
ELI5: Why does alcohol kill them germs when you put it on your skin, but not when you drink it?

When you pour alcohol(lets say 190 proof Everclear) on a cut it kills bacteria(and healthy flesh which disrupts the healing process, can result in longer heal-times), but how come when you drink it when sick(sinuses, fever, the flu), it doesnt kill the bacteria but seems to help it grow fast and makes you more sick.

Sorry for the run on sentence, I have a fever now and everything is all blurring together anyways lol.

[Assistant] Alcohol kills cells through direct contact. If you have an infection and you drink alcohol, its never going physically come in contact with the infectious germs. Its just going to enter your blood stream and make your body less efficient at fighting the disease.


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

[User] ELI5: Are breast implants removed after dieing?

[Assistant] No. There's no reason to do it really. It would make the body look worse, the skin would have adjusted to the extra material and would just look bad, part of the coroners job (as morbid as it sounds) is making the corpse look 'nice', removing implants would be counter to that.


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

[User]
ELI5: When getting a flu shot, how does the needle go in?

Does it go into the space between cells, does it break cells on its way in, or some combination of the two? I am having a difficult time visualizing how it works.

[Assistant] A combination of the two would be appropriate. The 'space' between cells is comprised of the Extracellular Matrix, which is a bunch of proteins that link the two. The needle goes through whatever's in its way.


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

[User]
Is it possible (in theory) to build a machine that can produce every smell/taste there exists without using anything organic?

For example, just like we define colors with RGB - combination of 3 0-255 values which can define "every" color in the visible spectrum.

Can we do the same for smell/taste?

[Assistant]
Taste is pretty easy to trick.  You have 5(ish) different taste receptors that respond generically to different chemical groups.  We don't experience taste as being this flat because our brains are good tricking us into thinking that the sensation of smell is part of what's going on in our mouths.

Smell is incredibly complex, though, and we currently don't fully understand how it works.  Our best theories explain the sensation of smell through molecular sensors in the nose that respond to the different ways molecules both dock and vibrate inside many specially shaped cavities inside proteins.  We know it has something to do with molecular vibrations because studies have shown that we can smell the difference between molecules that are chemically identical, but contain different isotopes (deuterium substituted for hydrogen is the most common example).  Isotopically substituted molecules have the same chemistry, but different fundamental vibrational frequencies.

All that is to say, because there are so many different ways we can smell things, the number of unique smells we are capable of discerning is estimated to be in the tens to hundreds of thousands.  Developing a universal mixture of compounds that can trigger the entire range of possible smells is near-impossible at this time.


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

[User] [MCU] If Iron Man and Cap traveled for Soul Stone to Vormir instead of Clint and Natasha, who would jump?

[Assistant]
Cap would easily. They might have their differences, but:

1) He doesn't trade lives, but he would  easily sacrifice his own. He's literally jumped on what he thought was a live grenade, self-sacrifice is who he is.

2) He knows that Stark can contribute much more in the long run. He knows that their plan requires Tony more than it requires him. If anything goes wrong with their gauntlet or they need to fix the time-travel or whatever else goes wrong, Tony is the guy that will come up with the solution. As good as he is, he knows that he's just a soldier.


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

[User]
What is the most efficient mechanism for converting matter to energy?

At the moment the most efficient I know of would be nuclear fusion. Is there anything thats more efficient?

[Assistant] The most efficient would be matter antimatter anihilation. Using this you will be converting 100% of the mass into energy. The problem is however, that you need antimatter in the first place which isn't just lying around.


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

[User] ELI5: How do fake passports work considering the passport numbers are linked to a government database?

[Assistant] Not every passport check is linked to the government database. Even those who are do not always look up all the passports they check as it takes time and may not validate all information in the database. So a passport with no entry in the government database or one which is liked to a different entry in the database will get you through a lot of passport controls. However it is not uncommon for the "fake" passport to be real valid passports just issued to someone else. Even if the passport checks are able to validate the passport it can be harder to verify that the person going through the control is the one in the passport photo.


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

[User]
[DBZ] How Did The Kais Defeat Buu In The First Place?

As in, how did they return him to his egg? Did they wait for the wizard to egg him, then they killed the wizard? Cause even fat buu seems to be able to hold himself against all the Kais easily.

[Assistant] Majin Buu Pure is a force of destruction not unlike Beerus, in that he wakes, destroys some shit, then hibernates. Originally he was actually hibernating but was woken from that sleep cycle by Bibidi, his first 'ruler'. After wreaking havoc all around the galaxy he came to the planet of the Kai's where he killed some, absorbed some, and became the Fat Majin Buu that we saw originally. In this form he was weaker, and more docile, allowing him to be trapped in the little ball, by Bibidi, that we first saw him released from. Bibidi was then killed by the Eastern Surpreme Kai. Thus ending the terror of Buu, for a while.


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

[User]
[Warhammer 40k/Star Wars] Would a space marine feel comfortable serving the Galactic Empire?

Say a space marine or any type of character from the warhammer universe ends up in the SW universe, would they be comfortable serving the empire, despite it's top two leaders being practionioners of the dark side? Would the dark side be classified as Chaos?

[Assistant]
Palpatine *does* laugh a lot. That kind of whimsy is usually a sign of Chaos infestation.

Best to get rid of him.

Not sure about Lord Vader. He's serious, not much of a schemer, doesn't engage in debauchery, and while he *does* kill a lot of people, he doesn't froth at the mouth while he does so.

Granted, it depends on the Space Marine, but they *might* try to kill Palps and put Darth Vader in charge.

*Or*...

They might try to kill them both and become the new emperor themselves. Except, they won't *call* themselves "Emperor", because **that** is heresy.


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

[User] The lunar cycle and the menstrual cycle are roughly the same number of days.  Did the former influence the latter, or is it just coincidence?

[Assistant]
The word "menstruation" is etymologically related to "moon". The terms "menstruation" and "menses" are derived from the Latin mensis (month), which in turn relates to the Greek mene (moon) and to the roots of the English words month and moon.

Interesting, but in reality it's probably just coincidence that the two are close in length. A lunar cycle is about 29.5 days, and a menstrual cycle is 28 days on average; they're close, but not really the same. Different mammals have different menstrual cycle lengths, and they don't seem like there's much rhyme to them. Chimps are 37 days, mice are 5 days, possums are 28 days (like us?!) and sheep are 16ish days. Given that a 1996 meta-study showed no correlation between lunar phase and menstrual cycle, most think it's coincidence.


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

[User]
[Daredevil (Netflix)] What gives Kingpin his superhuman durability? (Spoilers)

In the last episode of the first season of Daredevil, Murdock and Fisk finally get to face off. In the fight, Fisk receives repeated blows to his unprotected head by Murdock's sticks, which I can only assume are made of metal. This annoyed me a bit, as it broke my suspension of disbelief. Wilson Fisk is a normal human who happens to be a very good hand-to-hand combatant. Anyone else receiving multiple strong blows to the head like that would have a concussion at the very least, but more likely severe brain damage. So how was Fisk able to withstand the blows with no ill aftereffects?

[Assistant]
Have you ever seen those powerlifter dudes who train to break cement blocks with their forehead? Fisk's genetics allow him to have that sort of bone density/durability naturally. He would dominate any sport that involves strength or durability if he hadn't chosen a life of crime.

Also, consider the fact that peak humans in this comic book universe are at a higher level than real life peak humans. (in fact, this is the case in most fictional universes) A genetic beast like Fisk will be tougher than any real person.


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

[User]
[Star Wars] The rebels are clearly using ships built by the Mon Cala. The empire, even without its death stars, easily has the power to ruin planets. Why didnt Palpatine destroy Mon Cala and its shipyards?

Every capitol ship the rebels employ is a Mon Calamarj design, plain as day. Why didnt the empire destroy the people who kept supplying them these ships? They clearly had the strength.

[Assistant]
They did destroy Mon Cala - check out the 2018 Star Wars comics. The ships the Rebels had were those that escaped

The Imperial commanders in charge were initially worried about unnecessary collateral damage - you dont rule a galaxy by burning it to the ground.  Also, Palpatine was known to enjoy Mon Cala opera

But a crazed former Jedi forced their hand by staging a false flag terrorist attack against Imperial negotiators, sabotaging the peace talks and triggering an invasion by the Empire. Their attempts at preserving at least some of the infrastructure failed because of heavy resistance, so they just decided to screw it and bomb the whole planet to heck, destroying most of its underwater cities. At that point, it wasnt about whatever economic value Mon Cala could provide for the Empire - it was about sending a message

As it turned out, the former Jedis plan was to sacrifice Mon Cala by luring the Empire into destroying it, forcing Mon Cala ships to flee the planet and join the Rebellion. Apparently, he had some kind of Force vision that showed him that these ships would eventually bring down the Empire

Obviously, sacrificing an entire planet just to push a few capital ships into the Rebellion was not a very Light Side thing to do, but the Jedi was cuckoo bananas and had fallen to the Dark Side by then. All he wanted was revenge for Order 66, no matter how may innocents on Mon Cala had to die for it.


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

[User] ELI5 what is it about the structure of vegetables that makes them so nutritious yet contain relatively few calories?

[Assistant]
We cannot digest cellulose. That is the physical structural component of plants. Because we cannot digest it we cannot get nutritional value from it. We call it dietary fiber and it passes through our bodies mostly intact. We are able to digest other components of plants and so get many vitamins and such from them, but the sugars that make up their cellulose are locked away from us.

This is perhaps the greatest proof that we are omnivores and not herbivores.


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

[User] I have a ball. What is the least amount of information I need to give you about the ball in order to determine the mass of the sun?

[Assistant] If we're allowed to know *G* independently, then we can use Kepler's 3rd law to figure out the mass of the sun with just the semi-major axis of its orbit and orbital period. If we aren't allowed to know *G*, then other measurements are necessary to figure it out, which we can do by measuring the rotational moment of inertia of the ball, which with the radius yields the mass of the ball, and gravitational acceleration near the ball.


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

[User]
ELI5: What causes us to have a random "awkward" flashback, even though that flashback had nothing to do with what you were doing?

I'm talking about those flashbacks you have where you cringe just thinking about it.

EDIT: I should note; I don't mean an actual "flashback". More of a bad memory.

EDIT2: You're all awesome. Thanks for the answers.

[Assistant] Think of our brain as billions of lightbulbs. All thoughts light up places in our brain, and the brightest light is usually what we recognize. Once in a while, mostly when the brightest part is still quite dim (usually when we're doing something repetitive or boring), one of our "background" thoughts manage to create a brighter light than whatever is active. We switch over to that thought as "active", because that's the brightest.


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

[User]
[DC] Hold on. How has Lex Luthor not realized Clark Kent is Superman?

He's one of the smartest people in the fucking Universe. He's been face to face with Superman AND Clark Kent. He should be able to see past haunched shoulders and a pair of Glasses. What gives?

[Assistant] I've seen a comic where he had some computer system that figured it out. Then he got rid of it because the computer couldn't understand the obvious fact that someone with superpowers would never be content working a day job.


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

[User] ELI5: How does Iodine (pill form?) help reduce the effects of radiation poisoning if youre already irradiated?

[Assistant] It doesn't. Potassium iodide does one thing and one thing only: It protects your thyroid by blocking it from taking up radioactive iodine-131 which can cause thyroid cancer. It does nothing if you take it after exposure and it doesn't protect any other part of your body or protect you from any other radionuclide.


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

[User] ELI5: What is it about music that causes the brain to produce the physical urge to want to move our bodies? (dancing, foot tapping, head bopping, etc)

[Assistant]
The auditory cortex of your brain is connected to the striatum, the part of your brain which is responsible for the pleasure and reward system. Dopamine, which also stimulates movement, is released when a good song comes on.

When your auditory cortex is stimulated, you are compelled to move to the rhythm of the song. Moving your body in a coordinated way along to the rhythm produces more dopamine.

This is all triggered by music due to an evolutionary adaption. Bipedal hominids walking through the grass survive better if they take their steps at the same time. This produces less constant noise which allows them to hear things around them better in the quiet between the group's coordinated steps. The reward center of the brain in turn reinforced this behavior.

Thus certain sounds make you feel good, such as the rhythmic steps of another person, and you find it pleasurable to move along to that rhythm.


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

[User] Could I make the case that any sequence of numbers i choose at random, no matter how long, like 53948714, can be found somewhere along the digits of pi?

[Assistant]
The property that every finite sequence of digits can be found at some point in the decimal expansion of a number is called "normality". A "normal number" is a number that has this property. So your question becomes: Is pi normal?

The answer is: Probably, we don't know.

It can be shown that almost all real numbers are normal ("almost all" being a technical term that means that the set of exceptions has a Lebesgue measure (which is a way of measuring sets) of zero), but we can also construct examples of real numbers that have a non-terminating, non-repeating decimal expansion that don't contain every sequence of digits (for example: 0.10110011100011110000...).

Whether pi is normal or not is still an open question, but the fact that almost all numbers are normal makes it very reasonable to assume that it is.


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

[User]
ELI5: Why is it that when you increase voltage from 120 to 220, the total amperage ends up being the same as if you did not change voltage at all?

I've been trying to wrap my head around this for a little while. If you have 2000 watts at 120, the amperage is 16.7. If you have it at 220, it's 9.09. But that 9.09 amps ends up on 2 different legs, so you end up with a total of 18.18 amps. Isn't voltage supposed to decrease amperage? Whats going on here?

[Assistant] You're confusing stepping voltage up or down via a transformer (and since power equals voltage times amperage, as one goes down the other must go up) with the two phases of voltage that is supplied to a typical US house.  You aren't stepping anything up and down when you place a large appliance across both phases in order to provide it with a total of 240VAC. Most electrical devices in a house, of course, only need 120VAC and are connected across one phase (or the other) and the neutral wire.  Two phases of 120VAC, 180 degrees out of phase from each other, combine as a single phase of 240VAC when you connect a large appliance across both phases. Internal components inside that appliance that only need 120VAC (such as an electronic controller) will only be connected across one phase and the neutral wire.


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

[User]
ELI5: Why do horses that break one of their legs have to be put down?

Seems like they should be able to rehabilitate them. Especially if they are race horses and could be used to breed later in life, or potentially race again.

[Assistant]
Horse bones are very dense and hard to break. That also means they take a long time to heal. They are also under very high tension due to the way the ligaments are positioned meaning it is very hard to keep the leg in position to be healed.

There are also a lot of infection issues and horses get blood poisoning very easy from broken legs. They also get respiratory infections when they are immobilized for too long which is common when trying to rehabilitate them for broken legs.

They can be used to breed, but racing is nearly always out of the question. The healed bone is a point of weakness that means they are not able to perform to their best ever again. In fact in many cases they cannot perform at all and the leg will break again if they get too much weight on their backs or try to run too fast or too much.


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

[User] How does antibiotic resistance happen? What are the medical alternatives for people who have already developed it?

[Assistant]
People dont develop it, bacteria evolve it. When antibiotics are applied, some bacteria may survive because they have a mutation giving the slight resistance to low exposure. Every generation a few may survive this way. Recombination of bacteria genes through reproduction might give some even stronger resistance. So then the docs apply more antibiotics. This repeats because theres almost always some survivors, so resistance is always increasing. Its classic natural selection. Some might call it the resistance treadmill. You have to use more or stronger antibiotics to stay in the same place.
Solutions:
1. Stop overusing antibiotics because it helps to breed new resistant strains. End subtherapeutic antibiotics in farms, resistor it human use to bacterial infections (they dont treats viruses).
2. More, stronger or newer drugs
3. Use co-treatments like phage or chemicals that block other parts of bacterial metabolism and interrupt the pathways by which they become resistant.


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

[User] ELI5: Why do antidepressants cause such different reactions in different people?

[Assistant] Partially because the medical causes of depression are not well known - brain scans and blood tests of depressed people often show very different information. So prescribing anti-depressants is a guessing game, trying to find one that works for a particular patient is usually a trial and error process. Most antidepressants alter the brain chemistry and affect people in different ways.


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

[User] ELI5: How exactly does the skin healing ointment heal the cracks in the skin?

[Assistant]
Ointments can work in a variety of ways depending on the ingredients and what you are trying to heal.

The most common ingredient is one derived from a type of oil, usually petrolatum. This can vary and some are wax based such as certain lip balms but they all provide the same purpose which is serving as a moisture barrier. It keeps the crack or break in the skin wet. In the case of cracked skin this is usually enough as the cracks are typically caused by overly dry air in the winter.

The second is to provide a barrier to foreign particles. Think of it like plastic wrap for food. It can keep dirt and dust out as well as bacteria. This keeps the crack or wound from getting infected so your body doesn't have to use energy to fight a bacteria off and devote more to healing.

Lastly are the specialized things that go in there. In burn creams usually its different substances which can cool or soothe the area. In first aid ointment it can be anti-bacterial agents. In the case of cracks usually its just some vitamins or other things that may or may not actually provide any real benefit.


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

[User] ELI5: Having seeing that gif of the Amish building a barn, what building codes do they have to adher (ex. smoke detectors, etc.) and do fire departments treat fires differently if they are held to different standards?

[Assistant] Building codes are set at the city and county level, not the State level. Since the Amish live in their own communities (small villages or collections of farms) they do not have any building codes that they have to comply to save the standards of craftsmanship they choose to hold themselves to. But seeing as they see labor as a service to God they put a massive amount of time in planning the design and crafting of the barns. The final assemblies go very fast due to teamwork. The Amish are also some of the most skilled carpenters and wood workers in the country, so what they build is well built.


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

[User]
Why are there ginger/very light brown hairs in a lot of men's beards?

Even when a man has dark hair and no close relatives with the same hair colour, it still appears.

It also only seems to appear when the beard is a certain length, I've not seen bits of ginger stubble.

[Assistant]
Beard hair is quite different to head hair; it is coarser, curlier and doesnt fall out when we get older. Comparatively little work has been done on the genetics of human hair colour, but it is believed that in order to have a ginger beard you must be a carrier for the recessive gene on chromosome 4. With two copies of this gene you will have ginger hair all over, but with just one, the hair on your head will be brown or auburn and your beard will be ginger.

 BBC Focus Magazine, #199 February 2009

Hope this answers your question, at least partially!


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

[User]
[Batman] If Bruce dies, are his allies going to maintain such a strict "no-kill" rule?

Has Batman actually convinced everyone to take killing as seriously as he does, or do they just avoid it to avoid Bruce's wrath?

[Assistant] Some would, like Dick and Tim. They're more about Bruce's way of doing things. Others, like Kate and Damian wouldn't. Kate with her quasi-military background probably wouldn't hesitate to put down a threat like Joker. Damian is going to murk somebody the very night Bruce is dead.


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

[User]
[Star Wars] What would Obi-Wan & Qui-Gon have seen if they went into the Dark Side cave on Dagobah?

Honestly, you can extend this to every force user in the franchise. What do you think?

[Assistant]
It probably depends on *when* they entered.  All that's there is what you "take with you", i.e. your emotional baggage informs the scenario.  Obi Wan as a padawan and Obi Wan as a master are in very different places mentally.

There also seems to be an element of prophecy in the cave (Luke seeing himself in Vader, an allusion to his family connection), so it's possible they both see their great failures - Obi Wan watches Anakin burn, unable to help him.  Maybe Qui Gon faces Maul, or sees a vision of Obi Wan not able to cope with Anakin's needs, etc.


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

[User]
[Marvel] What are some of Bruce Banner's best "patience feats?"

Sorry if this belongs in whowouldwin more. I wanted to know what are some impressive feats of Bruce Banner resisting turning into the Hulk. What are some of the worst things he's been put under and come out green-less?

[Assistant]
There's a scene in the recent run of Avengers (before Secret Wars) where he directly accuses Tony of lying, cheating, and going behind the Avengers' backs with the Illuminati, the group that shot Hulk into space and led to World War Hulk, to try to stop the end of the multiverse. The big part there, is that Tony reformed the Illuminati after promising he wouldn't.

Bruce needs some heavy duty tranqs to hold back the transformation, but he stays completely straight with Tony the entire time.


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

[User] ELI5: Why do you have to fast before getting certain blood tests?

[Assistant]
it depends on the blood tests, however, its typically to get rid of all the fats and sugars that are suspended in your blood following a meal.

If you fast, then your body will process those fats and sugars from your blood. Whats left over are the risiduals which are produced by your body (ie, chloresteral, insulin etc...). By fasting they can get a somewhat accurate snapshot of the levels in your blood to know if you have high chloresteral due to your liver producing too much or insulin levels due to diabetes etc...


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

[User] How do companies put such specific expiration dates on products that sometimes go years into the future?

[Assistant] Expiration dates are almost always estimates that are added starting from date of production. A lot of foods can last longer than expiration dates and some things can even last indefinitely past expiration dates, but have them ("best by") to ensure quality. Like for example a lot of baking products like flour can last indefinitely as long as it's kept in an air tight container and is checked before use for things like bugs.


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

[User]
How would removing PBS help cut the deficit.

During the presidential debate Romney mentioned cutting things like PBS.  I know that it does receive some funding from the government, but most of it through fundraisers from 'viewers like you'.  What I wan't to know is would eliminating it completely actually help the economy or is it just a sort of 'empty example'.

[Assistant]
The federal government only provides about 20% of the NPR and PBS budget. He's just pandering. Cutting it would do nothing except abandon its audience.

Edit: The US Government spends $444 million a year on the Corporation for Public Broadcasting. The defense budget this year is over **$1 trillion**. That should give you an idea.


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

[User]
[Dragonball z] What is going on in transformations?

I have a chicken/egg question.

is it the power level increase that causes physical changes in the body, or the other way around?

Is the body adjusting to this massive amount of Ki? or is the key being drawn to this new form?
(this question is for all characters who transform)

[Assistant]
The Ki transformation concept is built upon from the early volumes since the scene of master Roshi went all buffy to gather energy/ki **before** blasting away the castle (to put out the fire) with his kamehameha. In Cell arc, 2 methods of Ki controlling/suppression between Son Goku and Vegeta (and their sons) lead to 2 very different transformations. However there are times where power level increased without clear physical changes, like Son Gohan's case in Buu saga (which made everybody surprised), or transformation to purposely limit power output (Freeza).

Its the power *manipulation* that causes physical change.


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

[User] [General] If time, or the concept of time, is different on every planet in existence, how would a galactic society be able to generalise time and age across the board so everything would make sense?

[Assistant]
This has actually been tackled by the real world Pioneer mission. The probe has a plaque with a lot of cool info on it, but also a means to establish a unit of distance and time to have in common with whatever future civilization discovers our space junk!

It's called the Hyperfine transition of neutral hydrogen (copied from Wikipedia):

At the top left of the plate is a schematic representation of the hyperfine transition of hydrogen, which is the most abundant element in the universe. Below this symbol is a small vertical line to represent the binary digit 1. This spin-flip transition of a hydrogen atom from electron state spin up to electron state spin down can specify a unit of length (wavelength, 21 cm) as well as a unit of time (frequency, 1420 MHz). Both units are used as measurements in the other symbols.


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

[User] How do brain-eating amoebas (e.g. Naegleria fowleri, Balamuthia, etc) know the way to the olfactory bulb after binding to the mucosa?

[Assistant] The olfactory nerves exit the skull into your nose thru the cribriform plate. It's just a thin bone with tons of tiny holes in it for the nerve fibers. Naegleria has a flagella tail so if you accidentally "snort" it up your nose when you are in contaminated water, the protozoan can swim up and enter thru the cribriform plate into your skull.


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

[User]
eli5 why do hands never get acne or pimples from touching dirty things

i was wondering about this hecause whenever i use a towel to wipe my face i get a few pimples but my hands touch way dirtier stuff everday consistently but they never get acne or pimples. Why is this?

[Assistant]
Acne is a disorder of hair follicles and sebum glands. The palms of your hands have neither of those things.

Acne is most commonly found on the face because that's where the majority of the body's sebum glands are, though it's also possible to have on the chest, shoulders, or back.


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

[User] ELI5: why do chip card transactions take so much longer to process than magnetic strip transactions?

[Assistant]
It's an Infrastructure Issue.

Chip Cards have added Security Features. These features are meant to make forging a Chip Card *incredibly* difficult, even if you manage to get a Skimmer working for them. However, more complex security features require more Computer Processing to verify and authorize.

The Chip Cards are new, and they're running on the older hardware made for Swipe Cards. This hardware isn't fast enough to do Chip Cards as quickly. You've basically traded some Time for Security.

Chip Card Transactions *will* become faster as the Infrastructure is improved. It's just a matter of waiting for companies to get that Infrastructure set up.


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

[User] ELI5: Why does it become much easier to tear plastic or similar materials once you have a small cut from the edge (or anywhere on its surface), but painfully difficult to tear them without any cuts?

[Assistant]
Stress concentration.

Let's imagine a sheet of paper, gripped evenly on both ends and pulled apart. Not hard enough to tear, yet, but it's in tension. Held in front of you, pulling left and right.

Let's look at the middle of this paper, a line running up the center - this line should be right between your hands as you stretch the paper sideways.

At any point on this line, the paper is experiencing maybe 1 pound per inch. That's not enough to tear it, but it's a lot.

Now we introduce a small snip at the edge of the paper - cutting the end of the line. It still hasn't torn. Imagine what the paper at that snip is doing - it's pulling apart now, so obviously it is no longer bearing that 1 pound per inch. Instead, the stress it would be experiencing is passed on to the paper right where the cut ended. The stretchier our material, the more spread out this stress is. Paper's not very stretchy, so you get a lot of stress concentrated right where your cut stopped. Way more than the original one pound per inch. At this point, the paper probably starts to tear where the stress is greatest. As the tear grows, this point of high stress is pushed along with it.


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

[User] [Marvel] I have cancer in an advanced stage with bad insurance and too many people counting on me to die now. Which super being good or evil is the most likely to be able to save me at the lowest cost?

[Assistant]
Hmmm...

Well, the list of people that *could* is still pretty exclusive, despite it being full of superpowered beings.

Mephisto: could absolutely and instantly cure your cancer, but there would definitely be a price you weren't comfortable paying.

Dr. Strange: with the advantage of having actually been in a medical profession (though he was a specialized neurosurgeon, so his expertise might be less useful in that respect than people think it would be), and Magic, he could almost certainly help cure you. Once again though, it's not going to be free. All magic comes at a cost, but unlike Mephisto, Strange would at least do his best to keep that cost minimal.

Most of the science based characters couldn't do anything to help you. End stage Cancer is End stage cancer, after all. Among them, your best shot  might be Reed Richards, who does, occasionally, make some forays into attempting cures for diseases. What it would cost you? Who knows. Reed varies between altruist and asshole at the drop of a hat. It might also take longer than you have left to live.


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

[User]
[Dungeons & Dragons] Why do wishes always go wrong?

Everyone knows not to trust supernatural beings who offer to make wishes come true. Genies and devils always try to trick you, and resolve wishes in the most ironic and rat-bastardly way possible. But what about spellcasters who cast their own wishes? Why do they need to be so careful and constantly worry that their intention will be interpreted not only literally, but twisted into the worst possible outcome? Why is it that such a powerful spell is apparently self-aware, and a real jerkass to boot?

[Assistant]
They don't. any good 18+level wizard knows the exact limitations of a wish spell it can give you money; 25,000 gp to be exact, power; any of your natural abilities can be raised by 10% of the human average; you can cast any spell less powerful than wish even if you couldn't normally cast it (for example because you don't have it prepared or aren't the correct class); or it can make you and one other being move to any place of your choosing regardless of distance. there are a few other things it can do that require the wizard to sacrifice a portion of their life essence like raise the dead or turn back time.

What you are unknowingly asking about is why people that try to bend the rules of wishing often come to such awful fates. well mostly it is because people who are in tune with magic are often negatively affected when magic is strained and casting wish without obeying the rules does just that. the links the wizard has to the world and magic don't weaken, they warp becoming channels for destruction and suffering.


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

[User] ELI5: How doesn't the ISS get hit with meteors during showers like the one this week?

[Assistant]
I actually do this for a living!

The basic answer is that space is so big you don't have to worry so much about impacts.

But the larger answer is that we (mankind) has characterized and generalized the meteorite flux to produce tables which say "for an object/spacecraft with a cross section of 1 square meter, N meteors of X diameter and Y velocity will impact every hour."

So you take this table and ask yourself how long you want your spacecraft to last, and how likely you want it be that it actually lasts that long.  For typical spacecraft that might be... 99.9% chance that you last for 8 years without getting destroyed.

You then use something like a Poison distribution plus your table to find the maximum meteorite size that you need to be able to withstand without being destroyed.

And lastly you use a meteor penetration model like Cour-Palais or Schmidt Holsapple (sp?) which were developed back in the Apollo days to choose how thick to a make your hull.  Eventually... some time after your 8 years, hopefully... a meteor comes around that is bigger than the limit you designed for and then your mission is over.  But it's ok, because all good things have to end, son.  You're happy.

Note those models aren't valid for two layer ("Whipple") shields which are pretty common now.  One layer fragments the particle and the other catches the little bits.  There are alternative models for this.


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

[User]
[Star Wars] Is there something about the human race that makes them such capable Jedi?

Yes, before you say it, I KNOW plenty of powerful successful Jedi and Sith have been races other than humans. But factually some of the most powerful and influential force wielders have been humans. Mace Windu, Obi Wan Kenobi, Palpatine, Count Dooku, Qui Gon Jinn, Starkiller, and the Skywalker line. Not to mention the most powerful sith lords, including Ajunta Pall, Darth Traya, Darth Bane, Darth Revan, Darth Malak, Darth Nihilus, and even Marka Ragnos and Naga Sadow were half human. Based on the star wars universe, humans are far from being the most populous race. Yet they seem to have force sensitivity strong enough to become the majority of the most powerful Jedi/sith in history. Is there any lore to support this? Or is it merely coincidental?

[Assistant] Yes, though humans are far from the most exceptional.  Yoda's species are ALL Jedi, and tend to be pretty powerful ones at that.  On the flip side, some species have a very small percentage of Jedi, like Hutts.  What is it?  A quirk of genetics, like how some races tend to be stronger, some faster, some smarter, some better traders, some better warriors, etc.


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

[User]
ELI5 exactly what Obama letting Bush's tax cuts expire means.

I've always found myself out of the loop, politically speaking. What does this mean?

EDIT: I don't know. I just don't understand politics I guess. I read an answer that kind of makes sense and then someone else tells that person how they're an idiot and wrong and explains why they're wrong and I'm back to square one.

[Assistant]
Back in 2001 and 2003, George Bush signed in a bunch of tax cuts that would last ten years. The cuts included reducing all five of the then-current tax brackets, as well as making a brand new super-low tax bracket for low-income earners. He also signed in a bunch of corporate tax cuts. He expanded deductions and credits on a variety of items. About one-third of the tax cuts went to the top 20% of the taxpaying population; about two-thirds went to the rest.

Now, in 2012, unless Congress does something, *all* of those tax cuts, plus the Obama tax cuts of 2009-2010, will all expire simultaneously. In addition, spending will be reduced on both the defense and nondefense budgets. These last two pieces are due to a legislative deal signed in 2011.

If all of those things happen at once, it would be a really big "fiscal shock." Taxes would go up, government spending would go down, and aggregate spending would probably fall. This would, in the absence of Federal Reserve action, cause a medium-sized recession.


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

[User]
Is there any browser extension which identifies and shows which programming languages have been used to create a site?

I know we can see the code by going to page source or inspect but I'm asking from a begginers perspective who struggles to identify languages.

[Assistant] No. All websites are written using HTML, CSS and JavaScript simply because nothing else runs in the browser. But that is just the frontend part, the backend can be written in literally anything and there is usually no way to tell because it runs on the server and you can't see the source.


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

[User] ELI5: Why do horses need to be put down when they break a leg while most other animals don't?

[Assistant] Horse bones are incredibly dense and fairly difficult to break, but when they do break they do not heal well, easily, or quickly and are very prone to infection. Most would die a slow painful death from infection, even with antibiotics and other medical care. Those that survive would most likely not have full use of the leg, and have a leg prone to break again.


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

[User]
Do black holes swallow dark matter?

We know dark matter is only strongly affected by gravity but has mass- do black holes interact with dark matter? Could a black hole swallow dark matter and become more massive?

[Assistant]
We don't really know what dark matter is.

The prevailing hypothesis is that it's some kind of particle that only interacts gravitationally (well, for the most part). If that's the case, then yes, black holes should definitely be able to swallow that stuff up.

Under that same assumption, it should be noted that dark matter will probably not form an accretion disk, nor would it care about an existing accretion disk. So dark matter particles would just describe conic curves around the black hole. If the curves happen to intersect the event horizon, the particles will be captured. Otherwise no capture will occur. (with some corrections to those trajectories due to general relativity)

---

If it turns out that dark matter is not particulate stuff, then all of the above does not apply.


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

[User] eli5 Why do internet calls such as WhatsApp sound clearer than normal cellular calls?

[Assistant]
Internet calls are a much newer standard. Part of this is the ability to transmit relatively better quality audio, which may vary depending on the codec used.

This is similar to how a VHS has worse quality than a DVD.


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

[User] [Harry Potter] could a killing curse destroy a horcrux?

[Assistant]
Yes. It did. The fragment of Voldemort's soul that was in Harry Potter was destroyed by Voldemort's Killing Curse.

It makes sense, since the function of the Killing Curse is to remove the target's soul from their body, and a Horcrux is part of a soul.


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

[User]
ELI5: Why do appliances use electricity when they're turned off but still plugged in?

I feel like this is either a myth or the electricity used is insignificant.

[Assistant]
It's real. The little blue light on a lot of monitors and tvs takes energy. Clocks on coffeemakers or stoves or microwaves. Things like cell phone chargers will continue pulling energy even when the phone is fully charged. A lot of electronics simply enter a standby mode rather than actually being powered off completely.

For an individual, it might not amount to a crazy amount of energy consumption. But multiply that by every household, and it's a lot of energy just being wasted.


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

[User] ELI5: how does poor dental health lead to heart disease?

[Assistant]
Poor dental health results in bacteria colonising the area around the bottom of your teeth next to your gums. Friendly bacteria normally live here, however in some cases nasty bacteria (usually Group A Streptococcus/various other nasty bacteria) overpopulate the friendly bacteria and can form a local infection. Some of the bacteria growing in the local infection can get into the bloodstream through tiny capillaries next to the gums and the next stop is the heart!!!
In some cases - particularly people who already have damage to their heart valves - these bacteria can 'stick' to the valves and form a colony there. This is known as bacterial endocarditis and is a severe infection that can damage the valves in your heart permanently. That is the main risk of having bad dentition (as far as i know)


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

[User] How does rabies evade the immune system?

[Assistant] It doesnt fully evade the immune system, which is why the vaccine/PEP immunoglobulins work. However it infects neurons which are immune privileged, the immune system generally leaves nerves alone to avoid very nasty side effects. The virus infects cell to cell slowly until making it to the brain, usually weeks later. Despite this the immune system can still clear the rabies virus, it is just usually too late and brain damage is fatal. Having the vaccine administered early along with the immunoglobulins (antibodies) clears the virus sooner, ideally before it reaches the CNS so there is no brain damage.


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

[User] Do we have any idea what is there in the universe 13.7 billion light years away from us, today ?

[Assistant]
We do. The farthest galaxy we have seen formed a few hundred million years after the big bang. The light then traveled 13 billion light years over to us and we see it today. As the light was traveling, the universe was expanding, that means that the galaxy was moving away from us as the light was moving towards us. That galaxy is now 30 billion light years away from us.

So we are pretty sure we know what the galaxy looks like within 30 billion light years of us. What about farther than that? Well, everywhere we look the universe looks just about the same. There are galaxies evenly distributed about the universe, in every direction (the universe is isotropic and homogeneous). Because of that we have no reason to believe that the universe is any different in the places that we haven't seen.


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

[User]
[The Flash] Does The Flash have a passive spidey sense that toggles on the Speedforce in the event that he is suddenly attacked while he is choosing to process reality at a normal speed? I.e. Can you cheap shot The Flash?

When The Flash is in a conversation he is not processing his surroundings at speed force reaction time otherwise conversations would take lifetimes from his perspective. Lets say a sniper fired a bullet at him mid sentence. Does he have some passive ability that senses oncoming danger so he would toggle on speed force in time? Is the Speedforce a soccer mom that looks out after him or is he just starring at your lips for 5 years as you talk?

[Assistant] In Mark Waid's run, Wally mentioned that he has a "Flash mode" and a regular mode. Once a bullet touched the back of his neck and he unconsciously snapped into speed mode, moving out of the way before it could penetrate his skin. Sometimes it happens at inconvenient times, though - when he was recounting this, he was listening to his father-in-law in slow motion and hating every second of it.


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

[User]
[Sci-Fi] How are there aliens that look exactly like humans in other galaxies, apart from their skin color? Also, how did they evolve to have blue/green/purple skin?

I understand that on Earth people tend to have darker brown skin if they're from a sunnier part of the planet, but what would possibly make them evolve to have green skin?

[Assistant]
>How are there aliens that look exactly like humans in other galaxies

Barring handwaves such as a common ancestor (near-humans of *Star Wars*) or essentially-magical common influence (*Doctor Who*), it is generally asserted that bilaterally symmetric quadruped bipedality is highly evolutionarily advantageous, at least in a mostly-similar environment (therefore capable of walking in the same corridors as human charecters), resulting in convergent evolution, similar to how the eye emerged independently evolved in multiple lineages on Earth.
>Also, how did they evolve to have blue/green/purple skin?

Because it was evolutionary advantageous to have whatever skin pigment they have, with additional caveats for whatever biochemistry they have. Why plants are green? Chlorophyll is hardly the only option; it may be possible to have bright white titanium oxide pigments, or biological solar panels composed of germanium. And an alien with coboglobin would blush blue because the oxygen carrier in the blood is blue and not red, and their traffic lights would probably reflect association of spilled blood and violence with a wholly different color.


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

[User] If the light from a galaxy 250 million light years away takes 250 million years to get to Earth, does that mean if one exploded today we would only discover it in 250 million years?

[Assistant]
Yes, you are correct.

If we observe a close star, for example, say one about 250 light years away. The light we are seeing today was produced from that star 250 years ago.  In another 250 years, we will see what that star *really* looks like *today*.

In this way, astronomy is a form of seeing back in time.


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

[User]
[Star Wars] Who buried Darth Bane in a tomb on Moraband/Korriban?

Would his apprentice have done all that work after killing him? If the Jedi or someone else killed him, why would they give him a dignified traditional Sith monument?

[Assistant]
>Would his apprentice have done all that work after killing him?

Why wouldn't they?

Thing about Sith - and any other tradition that follows Klingon promotion guidelines - the stronger and more respectable your defeated rival is, the stronger and more respectable *you* are.  Bane wasn't an enemy to his apprentice.  No Sith is a true enemy to their apprentice.  The Master is a challenge, the wall that the apprentice must break through to reach mastery.  And the greater the challenge, the more pride one feels in victory.  Basically, by honoring Bane in his death, his Apprentice is doing honor to himself as well.


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

[User] [Batman] How could Kids and Civillians trust Batman at first, He's Terrifying....

[Assistant]
Well for civilians, public reception is usually divided. You get the pearl clutchers, the fans, the apathetics, the assholes in hockey pads, etc. However, most people recognize that there wouldnt be a light with his symbol on it if Gordon didnt think there was something worthwhile about the guy, and it turns out Batman can be pretty nice when you meet him if youre not a criminal.

As for kids, Bats usually goes out of his way to be nice or try and help them out if needed. Plus, most dont really care about the ethics of vigilantism as they do cheering on the guy with the cool car and costume who beats up the bad guys.


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

[User] ELI5: How do newborns learn to keep their eyes open?

[Assistant] Most babies will tend to open their eyes more if they are held in an upright position (this is called the "doll's eye" reflex). Their vision is very out of focus at first, but they can see things within 6-10 inches away, and they are naturally fascinated by human faces, which is why it's so important to interact with even tiny newborns. Newborns sleep a ton during the first few weeks of life, so they do spend a good chunk of time with their eyes closed, but often they really enjoy being held upright and staring at mom or dad's face! Sight is the last sense to develop in newborns, so while they can often hear extremely well, their eyesight is very poor in the beginning. As their vision gets better and they are more able to focus their eyes on different objects, they keep their eyes open for longer periods of time and will often become fascinated looking at different colors and types of movement.


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

[User] ELI5: In a situation of constant hyperinflation (eg prices doubling every few days), how do individual shopkeepers know when to raise prices by how much?

[Assistant]
In most cases when this actually happens or is close to happening, the answer is "they don't". Many will stop producing (because presumably raw material costs are also doubling) and no one wants the wages paid in a currency that buys less every day.

1. People start to barter trade.
2. More frequently, they only accept foreign currency that is more stable.

The problem is that the price charged has to account for the increased price of new supplies plus compensation for the buying power lost in the intervening period (as income to the owner). Ultimately this is self defeating, since higher prices drives even higher prices which is why hyperinflation is destructive. The economy simply breaks down as trade fails. People try to exchange their money for goods (leading to hoarding) and the luckier ones exchange for foreign assets and currencies.


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

[User] ELi5: What causes decompression sickness, and is there such a thing as compression sickness?

[Assistant]
decompression sickness is caused by nitrogen bubbles forming in the blood vessels, kind of like how when you take the cap off a soda it starts bubbling. compression sickness isn't a thing because by the time getting more compressed hurts you it's just breaking your ribs/crushing you in other ways.

Edit: as pointed out by others on this post, there is actually "compression sickness", go give them upvotes.


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

[User]
From a mathematical perspective, why can't white holes exist?

Could someone explain precisely why physicists so fiercely dismiss the concept of white holes as a possibility, when they are a direct(ish) implication of Einstein's theories of relativity? Is there any mathematical theory that disagrees with the concept in any way?

The Higgs Boson only ever existed theoretically, but it's recently been discovered (they're 99% sure now) thanks to technological advances at CERN. It seems to me that in dismissing white holes, we are dismissing ideas that we can't even begin to test, when extrapolating from accepted theories (like relativity) is our only available means of providing any tangible glimpse into the great mystery of the black hole.

I saw a video that said they couldn't exist because they would violate the second law of thermodynamics, but white holes are in some small sense implied by black holes aren't they, and don't all of our standard rules sort of break down inside the event horizon of a black hole anyway? So if the second law somehow supercedes what we expect to happen in a singularity, how does it do so?

Speculatively, is it possible that at the singularity of a black hole, spacetime is broken down completely and the matter falling in reappears (dismantled beyond recognition by the tidal forces) at the big bang at the very beginning of the universe?

I've recently gained a profound interest in the happenings at the very limits of our universe: the Big Bang, black holes, the infinitesimally small (quantum) and the infinitely large (outside the observable universe). I've also been looking at the zany suggestion of a fractal universe, which has been suggested from both small-scale and large-scale theories. I'm in the second year of a mathematics degree so at least to me, an 'undefined point' in our universe seems perfectly analogous to an undefined point for a simple function, so why should a mathematical assertion for conditions within the *physical* universe be so unreasonable? It would be really awesome if you science people could provide some answers for my increasingly achey head!

P.S. I'm sorry if I'm not the first one to ask this but I've looked through a couple of the relevant questions and couldn't spot anything discussing exactly what I'm trying to find out.

[Assistant]
It's not a mathematical prospective that forbids them to exist, it's that there's no process of stellar evolution that leads to their creation, nor is there any observational evidence of them.

You can however have an acoustic white hole, which you can make with your sink.