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ELI5: How snails form their shells | I have a pet snail. Is its shell built by the snail as it grows and needs more space? Or does it grow like a toe nail? How is it attached?
Bonus question: how different are snails and slugs? | 249 | The shell is attached by the inner surface, and it grows a bit like a toenail. Snails and slugs are not exactly taxonomic terms, but in general they're actually pretty far apart.
Assuming you're talking about just land ones, snails are generally herbivores while slugs will eat anything. Dead animals, insects, plants, mushrooms, worms, and all sorts of things will get eaten by slugs while snails will *usually* stay away from most of that. There are carnivorous land snails though and many water snails also eat meat. | 110 |
[Mad Max: The Road Warrior] Where is everybody else getting their gasoline? | There’s just no way mutual scavenging is how everybody gets gas. There has to be a source of fresh gasoline somewhere in the wastelands, somewhere other than Pappagallo’s oil compound. Max has gotta be running through a tank a day because all he does is drive. Humongous and all his marauders, too, from their constant siege of the compound. There’s tremendous amounts of fuel being used every day, where is it coming from? | 27 | Mutual scavenging isn't getting *everyone* gas. Gangs like Humungus' one kill or leave for dead the people they rob. Humungus gang has a bunch of fuel to burn driving around because they presumably do this full time, and just finished up murdering some *other* poor bastards and stealing their fuel.
Max presumably travels from one relatively peaceful settlement to another, making deals for more gas. Almost nobody is thinking about the long term at this point, they know its unsustainable, they just want to go as long as possible before they're the one at the wrong end of the murderstick. | 30 |
ELI5: How does the heart make its own electricity? | 61 | The explanation by frommerman is incorrect, it is electricity and the sinoatrial node is not a cluster of nerves. The cells of the heart have the ability to pump ions across the membrane such that the inside is usually negatively charged compared to the outside. When the cell gets hit by the action potential, there are voltage gated ion channels in the membrane that open, and then the cell becomes depolarized. This opens other channels and makes the heart contract. The cells then reset themselves to restore the normal negative resting membrane potential.
The sinoatrial node is composed of specialized heart cells that have special channels such that they are leakier than the normal channels, so it sets itself off every once in a while (aka every heartbeat). If the sinoatrial node is broken for some reason, the atrioventricular node also goes off but more slowly than the SA node, and if the av node breaks there's the his-purkinje branches.
People who have had heart transplants do not have nerves that connect to the heart, but the heart will still fire on its own. The vagus nerve tells the heart to slow down usually, but a transplanted heart doesn't receive nerve signals from the brain/spinal cord. So it usually beats at about 100 bpm, which is what the SA node would do without external regulation.
We measure electrical activity in the heart via an ecg, an electrocardiogram.
Edited to include the part about heart transplants not needing nerve innervation to beat. | 19 |
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Why do some vaccines leave scars? | I recently got my BCG vaccine as I work in a lab but when they informed me of the blistering and scaring phase I was a little perplexed.
What makes the site blister and scar only after several weeks/months? I know it’s to do with your immune system reacting but what is specifically involved / what’s the processes involved and why does sometimes it cause such a prolonged severe reaction at the site of injection? ( How come its only with live vaccines too?) | 170 | For the smallpox vaccination, "leaving a mark" is the sign that the vaccine worked. The vaccine requires multiple punctures giving multiple infection start sites, so it becomes very inflammatory - leaving behind the scar tissue. The TB vaccine is different, in that it is a single injection, but BCG is extremely immunogenic and causes severe local inflammation, which can cause a long-lasting scar. | 96 |
[DC] How could the Joker overpower Batman? | Batman, having trained and learned many martial arts, and pushed himself to near human perfection, was overpowered by a lunatic who has only unpredictability as a serious fighting advantage. | 16 | Not just unpredictability, but his mind is as strong laterally as Batman's is deductively. The Joker would find ways to strike through every system of reality that depends on some form of logic. Language, art, sociology, economics can all be perverted and weaponized against Batman since his strength is in having such deep connections into any system relating to Gotham's infrastructure.
"But what does this have to do with combat?" Everything. When they fight, they aren't fighting like boxers with punches for the sake of breaking their opponent physically. They fight like chessmasters with any overpowering of Batman, to a layman, looking like he was put into check. The thing is that they are playing a game of chess by moving each piece in inhuman ways, representing every citizen of Gotham, with rules that they create and neither could ever win.
**-----Edit** For comparison, this is how someone as intelligent and strong as Bane can only assume breaking Batman's back would break *him* as if he was merely someone pushed near human perfection. Bane's mind is savage, but austerely rational. Reality to him is as much of a prison as the one he was raised in. For the Joker, reality is just another Arkham he can break through by sneezing.
His opponent is Batman-the-Symbol. It would be a joke to think you can benchpress/venom/artificially scare/freeze/riddle your way into Gotham's embrace. | 27 |
[Dune] Why is the Emperor upset at Leto's death when he planned it in the first place? | Did the Emperor only plan on the downfall of House Atreides and their failure on Arrakis, not expecting the Harkonnens to outright murder Leto? It says in the excerpt at the beginning of Book Two that the Emperor "went into such a rage as we had never before seen" upon hearing the news of Leto's death, blaming everyone except his self. No spoilers please as I have only just finished Book One. | 100 | Shadam is upset, because although he wanted to take House Atreides down as a potential rival, he also knew Duke Leto himself was personally very popular in the Landsraad. If it became publicly known he was involved with Leto’s direct murder, it might cause the other great Houses to turn against him. I’m sure he wanted Leto dead, but by accident or misadventure. Worse, Leto looks like a hero by almost taking Baron Harkonnen down with him. Only thing worse than a murdered Leto is a martyred one | 201 |
[MCU] What is the Iron Man mk.84 or whatever made from nowadays? I ask because sometimes they withstand a lot of battle damage, and others they get ripped apart like tin. | 44 | I assume you're talking about ironman 3 when you talk about the Ines being ripped apart:
It seems like in that movie, most of the suits weren't really being destroyed so much as falling apart, which was also the first instance of them flying and assembling onto Tony on the fly; it seems that the sort of force field holding the suit together failed rather than the materials. (Avengers two had them fly to him as well, but maybe the bracelets helped?)
By the next avengers movie Tony has solved that problem and they're nice and sturdy.
(In the third ironman, Tony was also pretty mentally messed up, so he also seemed to be going for quantity over quality) | 33 |
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ELI5: why are most top fuel dragsters V8 why not use V10 and V12 to go faster?. | 20 | The NHRA regulations constrain the engine used to power a Top Fuel drag racing car to the basic layout found in the second generation Chrysler 426 Hemi made from 1964-71. Although the Top Fuel engine is built exclusively of specialist parts, it retains the basic configuration with two valves per cylinder activated by pushrods from a centrally-placed camshaft. The engine has hemispherical combustion chambers, a 90 degree valve stem angle; 120 millimetres (4.8 in) bore pitch. The configuration is identical to the overhead valve, single camshaft-in-block "Hemi" V-8 engine which became available for sale to the public in selected Chrysler automotive products in model year 1951. The engine displacement is limited to 8,190 cubic centimeters (500 cu in). A 106-millimetre (4.1875 in) bore with a 114-millimetre (4.5 in) stroke are customary dimensions. Larger bores have been shown to weaken the cylinder block. Compression ratio is about 6.5:1 . | 35 |
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ELI5 How my modded xbox 360 controller can remember what mode it was last in, even if I take the battery pack out and put it back in. Why can't an alarm clock do the same? | 16 | > Why can't an alarm clock do the same?
It is not a technical issue, it's a social and economical issue.
If you need to change the mode every time the controller has powered down, you will need to do it a couple of times a day. A couple of times per day is making it annoying enough that you want it to get away. Enough annoying that you are willing to pay for having such a feature.
Replacing the battery is something you do every year once. Not enough to annoy you and pay for a clock which doesn't need to do this.
Because you are not willing to pay for it, the shops aren't interested in stocking them. The suppliers aren't interesting in making them. The chip manufacturers realize that they can save 1 cent on their chip by removing this "let it remember the time" feature, meaning their product is cheaper to make and thus more profit for them.
And that is why crowd funded projects like on kickstarter are such a hit for niche products which make sense for a small group of people who are willing to pay for the extra features.
| 14 |
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ELI5: If someone drilled a hole completely through the Earth (through the crust, mantle, outer and inner core), and disregarding the heat and pressure, I were to drop a object through said hole, would the object "fall" to the other side or would it stay in the middle of the Earth due to gravity? | 1,333 | It would fall to the other side of the earth, if there was no air resistance. It fall down until it reached the center, where it would be at maximum speed, then it would continue to "fall" up until until is reached the surface. At which point it would turn to fall back again.
If you also conciser air resistance it would not reach the other side, but go back and forth until it eventually come to rest at the center of the earth. | 497 |
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ELI5:If by definition an invasive species is a 'plant or animal that is not native to a specific location, and tends to spread and cause damage to the environment', then why humans aren't considered an invasive species? Do we not perfectly fit that definition as a species? | 291 | Yeah, we pretty much are, though we tend to think of "not native" as "humans brought it here and it didn't spread here on its own". You could look at things like National Parks or the Antarctic Treaties as being similar to trying to control an invasive species - "this is one of the few places that humans haven't invaded and destroyed yet, so let's put controls in place to try to keep it that way". | 137 |
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[Avatar: TLA] Can a non-firebender challenge a firebender to an Agni Kai? | 33 | It would appear to be a form of ritualized combat that requires firebending, as evidenced when Azula, in her role as Fire Lord under Phoenix King Ozai, commanded Lo and Li to engage in Agni Kai. Their response was "But we're not firebenders," which seemed to indicate that Agni Kai would be impossible for them. | 69 |
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ELI5:What exactly happens in your body when you drink water? | I get solid food, but what specifically happens when water enters the stomach and then afterwards. | 152 | Your body balances the water in the blood, the cells, and the spaces in between. A small amount stays in the intestines to help digestion while most is absorbed into the body across tiny pores. When the water crosses the pores it also helps transport vital electrolytes into your body. Then the water enters the blood stream and quickly reaches a balance with the other spaces: the insides of cells and in between the cells. The kidneys use the water in your blood to filter the waste products into urine. Some water even goes back into the lower intestines to help make stool. | 100 |
ELI5: Why are curved stretches of highway tilted? | 44 | This is called banking, and it's done to prevent cars from sliding off the road at high speeds.
When you're driving in a straight line, all the energy of the vehicle is aligned with the direction of travel. If you were to slam on the brakes, you'd decelerate in a straight line.
However, when you're going around a curve, your energy becomes compound. It's not just in a straight line in front of you, but also away from the center of the curve. If you were going around a curve, and the road suddenly turned to ice, you'd continue moving forward, but also *outward* along the radius of the curve.
The banking is done to offset this outward energy and help cars stay on the road - without the banking, taking even a large turn will run the risk of the vehicle sliding left or right, since the amount of friction between the road and the tires is finite, and can be overwhelmed by sufficient speeds. | 46 |
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Was always warned to stay away from windows and off/away from electronic devices (television, computer) during a thunderstorm. How valid is this claim, and how dangerous is it really? | 157 | Mythbusters tested this. If you have Netflix then you can watch it. It's the episode "Son of a Gun" (s01e11).
The phone did allow the current to go through (if the fuse wasn't grounded) and it would have killed someone.
They also tested if someone was in the shower "as if they were standing on a drain, and the drain was grounded," and it also was "plausible" to kill someone.
Both of these happened in a "best case" scenario. | 36 |
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[Harry Potter] Will Wizards eventually adopt muggle tech as national surveillance states increase in number? | I can imagine why wizards would not want to use 1990s tech, but in todays world when litteraly everyone has a cellphone? Where China's government can observe your every move? If wizards don't adopt muggle tech, they will be discovered. | 16 | They seem to be doing fine. While your average wizard is as dumb or dumber than their magic stick, they got staying hidden and ereasing muggle memories basically perfected.
Magic also fucks with electronics. Very simple devices like radios seem to work if powered by magic, but a wizard with a regular cellphone probably would not. | 16 |
[Rick and Morty] How did Rick _____ if ________? | How did Rick fabricate the details of his backstory in season 3 if, as revealed at the end of season 5, it ended up being his real backstory? | 38 | Rick used his actual backstory to build his illusion in the Shoneys; the bug didn't see the real memory, just a brutally accurate simulation of it, up until the moment when Past Rick writes the code for the malicious upload.
As far as telling the bug it was *all* a lie, Rick is an asshole, hates authority figures, and has an especially big chip on his shoulder towards the Gromflomites and the Federation. He knew it didn't matter what the big knew or didn't know, his information was safe, *he just wanted to twist the dagger in the dying bug's guts a little more before leaving*. | 60 |
Why would there be fish in a lake not connected to anything? | There is a lake near me in an abandoned quarry. It's at the top of a hill so nothing really flows into it and there aren't any rivers flowing out of it because it's just a big hole that's been dug into the granite. I was very confused then when I got closer and saw that the lake was full of little fish. How could they have gotten up there? | 31 | Well considering fish don't spontaneously appear, it's only one of two options:
1. They were put there at some point in the past
2. A source of water that contained fish was connected and allowed a small population of fish to migrate to that lake | 23 |
[Naruto] How the hell is chidori/lightning blade an assassins technology? it's way more flashy than the rasegan and it's loud as shit so loud that it's named by the loud high pitched sound it makes | "technique" | 34 | Chidori is an assassination technique in the same way old school Hashashin had a technique where they would get drugged up and charge straight at their target with a knife.
The idea is if someone charges straight at their target with no regard for their own safety, it is very difficult for their target to survive. Indeed, Chidori is criticized for being a reckless technique to teach when Sasuke first uses it. | 53 |
[Star Wars: Rogue One] I just saw a blind man with a stick knock out a fully armored stormtrooper. Is their armor effective against anything? | 93 | Its designed to protect against shrapnel, as blasters that miss tend to make the wall explode.
Hard Armour is usually bad again blunt force, which is why you attack a Knight in full plate with a hammer and not a sword | 156 |
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[Star Wars] By the time Ep.IV takes place, did Darth Vader know Obi Wan had survived all this time? | After being healed up by the Emperor in Ep.III, it seems likely Vader would have known that Obi Wan was still roaming around somewhere, but is there anything to suggest Vader ever tried to find him or confirm whether he was dead or alive over the next 30 years? I guess the same question would apply to Yoda. | 42 | I think Anakin/Vader would've known if Obi Wan had died, so he had to assume he was still alive. As for seeking him out, I'd imagine after he recuperated (as best as someone dipped in lava then shoved in a mobile respirator can), the Emperor kept him too busy quashing rebellions and executing his will. That being said, it's also likely that he was specifically being sent to places where remnants of the Jedi order might happen to pop up. It would make sense for them to join the rebellion if they decided to come out of hiding.
The problem is that even with force sensitivity and the tracking power that offers, the galaxy is still a big place. It would be easy enough to keep one's head down, keep out of sight, and stay mobile. Life's hard outside of the core worlds, but certainly not impossible for someone with Jedi skills. | 44 |
Many supermassive Black Holes emit relativistic jets. Would a White Hole be expected to have similar in-falling jets? | 24 | Hey, astronomer here:
I don't really think this would happen, primarily for two reasons:
1.- Jets observed from black holes are not "emissions" from the blackhole itself , blackholes' only known emission method is Hawking's radiation. Jet streams are result of gravitational interaction with the dust surrounding them with lots of relativistic velocities and angular momentum equations, that end sending up matter in the rotation axes of the bh. Having said that, you can think of jets as gravitational pull consequences.
2.- If white holes would be like the exact opposite of black holes, this meaning "massive sources of matter emission in every direction" i don't see any reason why this type of emission would generate a pulling force on the rotation axes of the object. | 27 |
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CMV: Telling People to "Just Be Yourself" With Regards to Dating is Horrible Advice. | I want to clear up some probable misconceptions that people are going to have.
I am NOT saying that it is wrong to be happy with who you are or that it is a good idea to take on a false/deceptive persona to succeed in dating. What I am saying is that far too often people are given advice along the lines of "just be yourself and love will find you when it is right". Another, equally bad piece of advice is along the lines of "You should never try to change yourself. If someone doesn't love you for who you are, you're better off finding someone else."
These sounds like perfectly reasonable pieces of advice. Here's the problem though: this advice discourages people from honestly assessing their strengths and weaknesses and making concerted efforts to improve themselves as a person. It encourages complacency. We should always be seeking to change, reinvent ourselves, and evolve. If people have spent their lives being extremely unsuccessful at dating, clearly something is wrong and something has to be done to improve the situation. People don't accidentally fail at dating.
Unfortunately, this is advice is grounded in the horrifically unbalanced way in which Hollywood depicts romance & relationships. Our society has the broken notion that even the unmotivated , slightly out of shape and comically awkward guy always seems to get the girl. I'm sick and tired of hearing the old and obviously wrong notion that love is something that just falls in your lap rather than something that needs to be worked for and earned. Society doesn't owe me anything. Women especially but occasionally men often fall into the trap of fate and "The One". No magic is involved with finding someone to date. The harsh reality is that if you don't earnestly work on becoming a better, more appealing person, there is no reason for the girl or guy "of your dreams" to want to be with you. If you have flaws, it is better to work on improving yourself than to sit back and expect to find an amazing partner regardless.
Far better if more nuanced advice would be something along the lines of "Don't be yourself... Become the best version of yourself." Working hard to improve yourself is important for any area of life, whether it be academics, sports, business or any field. No one ever told Wayne Gretzky to "just be yourself" when he was starting out in hockey. He still needed coaches to point out when he had flaws in his play and where improvement was needed.
TL;DR Society has the wrong idea when they tell people to be themselves in order to succeed in dating. Hollywood unfortunately pushes the idea of fate and one true soulmate which is not in line with real life. Better advice is to encourage real growth and development, not to fall into a pattern of stagnation. CMV
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | 55 | To me, "be yourself" means, don't present yourself as someone you're not, because you wouldn't want to date someone who is only interested in the pretend-you. Like, let's say you think guys won't like you if you're a smart, nerdy gamer girl. Wouldn't you get more out of a relationship from someone who likes you for those qualities rather than someone who would date you after you pretend to be a ditzy, clumsy idiot who can't tell a Playstation from a Gameboy?
I think you're reading too much into it and "be yourself" means exactly what you want it to mean. | 49 |
ELI5: How did they get, and keep, the footage of the atomic bomb tests? | You've seen the footage: those orange-red tinged shots of the car and bus being blasted across the desert, the shockwave hitting the trees and making a "forest" shimmy, and the house blistering into ashes.
So with all these thermonuclear torments, how the the camera stay trained on the spot, and how did the film not vaporize? What about retrieval? Don't get me wrong, I'm not some truther who's trying to say it wasn't real or the Freemasons did it (we had a pancake breakfast that day so we're good on alibis), or any such nonsene. Just curious.
Was camera tech good enough back then to have super long-range zoom? With the terrible force and energy, the shockwave pushing out and the negative pressure return wave what was used to stabilize the image? How was the recording possible with the presence of EMP? | 26 | First of all: for most shots of the blasts themselves, the camera was with the human observers i.e. sufficiently far enough away to be safe from massive shockwaves. Zoom lenses did not need to be super zooms, given the sizes of the explosions. Some cameras were put in massively heavy enclosures to survive being closer e.g. to capture the shock wave effects on structures and animals. You can design such things if you have an estimate of the conditions, which they did.
Plus: who's claiming that no cameras or film were ever destroyed? I'd be very surprised if that never happened! | 11 |
ELI5: Why can we only see so many stars in our own galaxy, but we can see the Andromeda Galaxy billions of light-years away with the naked eye? | 22 | That's kind of like asking why you can see the moon, but why can't you see a grain of sand 100 yards away. The sand is much closer, but the moon is much bigger.
Andromeda Galaxy is 220,000 light years across and contains a trillion stars. A typical star is 1.4 million kilometers across. That means a star is 0.00000000006726% as big as a galaxy. Also, Andromeda is "only" 2.5 million light years away - not billions of light years. | 19 |
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Is Plato's Republic a good place to start? | I got Republic and dialogues of Socrates from my local bookstore and am about halfway thru book 4 in Republic rn. I've been annotating the text, by highlighting and writing annotations and explanations to sections and that has helped me a lot. I just want 2 make sure I'm not picking something that's like a bad place to start. Should I have started with DoS? It's a smaller book and chronologically came out first.
Thx for any and all help | 46 | I would have started with something like the Crito as way of getting into the dialogue format and how he gets the character of Socrates to argue. The republic is jumping in the deep end, but its not as bad as the laws. | 26 |
What do you recommend me? | Hey I'm 16 years old and I know C and a little html. A lot of people recommended me to learn python and stick with it.
What do you guys think? Should I learn python and work with it? If so, what are some good courses that you can learn python?
Thanks in advance! | 17 | Python is an easy to use tool for nearly everything. It's good to know Python.
On the other hand, if you are good with C, stick with it for a little bit, just to become even better. There is almost no language that you cannot understand if you are a decent C programmer. It's literally a 70's language that survived that long. There is a reason for it. | 31 |
ELI5: How do streaming services analyze the success of their shows/movies? | With the strong influx of movies being created by streaming services like Netflix and Hulu, how exactly do they know if their movie was a success?
For example, if a studio like Warner Bros created a movie with a final budget of $10m, they can analyze their success based on the revenues. If they made >$10m...it was a success, right?
So how can streaming services deem their movie a success if they simply only provide revenues through subscriptions? | 39 | They look at details like:
- How many people watched it?
- How many people watched it right after signing up? (Assuming that the show is what motivated people to join)
- Did signup rates spike when the show was announced or became available?
- How many people watched it as soon as possible?
- How many people, after watching episode 1, went on to complete the season?
- How quickly did people binge the whole season?
- What did people rate it?
- Did the enthusiastic viewers (completed entire season, rated highly, and/or watched quickly) fit into a neat demographic (18-29 year old men who watch lots of scifi) or a broad one?
There's one kind of surprising detail that Netflix and streaming services are looking for that traditional TV networks aren't: *enthusiasm*.
With a traditional TV network, supported by ads, the only thing that matters is the number of viewers. The more viewers there are, the more valuable the ad slots are. 1000 viewers who say "eh it was mediocre" are preferable to 500 who say "I *loved* it."
With Netflix, enthusiasm can matter more than overall viewership. 500 people who *love* a show are better than 1000 people who watched it without really caring. Because they're not selling adtime, they're selling subscriptions, and people won't pay for a service that has ten mediocre shows but they *will* pay for a service that has their one alltime favourite. So Netflix's metrics aren't simple viewership rates (although obviously overall viewership matters) but also enthusiasm rates.
One area enthusiasm really matters is in demographic divide. In the TV industry, the goal is to have each show appeal as much as possible to the five key demographics (Males, Females, Teens, 18-49s, Seniors). When you pitch a show to a network you're expected to identify the two you're strong with (Breaking Bad: men 18-49, Pretty Little Liars: female teens) and then there are meetings on how to cater to the other 3. If you pitch an action series about street racing spies they'll want you to add romance for female viewers, tone down the violence for teen viewers, put some 60s/70s rock in the soundtrack for older viewers, for example. The aim is for the show to be tolerable to everyone, even if those changes make it less appealing to the core demo. This is less about drawing old/teen/female viewers to the show and more about making sure that nothing in the TV schedule is so unappealing to anyone that they'll turn it off, since people usually watch TV in multi-show blocks with other people.
Netflix's goal is very different. It's better for their business model to have shows that only appeal to individual demographics, but which evoke intense "I would pay $9/month for this show alone" enthusiasm. You create these shows by doing the *opposite* of what the TV networks do -- you pick a demographic and focus solely on them. | 38 |
ELI5: Why do our nipples get hard when it's cold out | 2,426 | This is an interesting question, with an interesting answer.
basically its to reduce surface area so its harder for them to cool down further, as to not get nerve damage, and keeping the body warmer.
/u/penguinluvinman has a great answer.
>When exposed to cold temperature skin reflexively contracts, causing the nipple to become smaller, wrinkled and "hard." The ultimate function of this reflex is to decrease the amount of surface area on the nipple that is exposed to the cold. This decreases the amount of body heat that is lost to the cold and ultimately the amount of energy it takes to sustain homestasis (keeping normal body temperature) in an organism. So decreasing surface area is the ultimate reason why nipples get hard in the cold. It's the same thing as goosebumps on other parts of your skin.
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[eli5] What actually is food poisoning and what is happening in our bodies that make them respond so violently to it? | 52 | Food poisoning happens when you eat some bad bacteria living on/in your food. These bacteria (commonly staphylococcus aureus and bacillus cereus) make a toxin and spread that toxin all in your food. When you eat that toxin, your guts are like “this is a bad thing so let’s get rid of it” and your guts get rid of it with vomiting and diarrhea. The vomiting and diarrhea get rid of the bacteria and essentially clean you out.
Some bacterial diarrheas last longer but that’s because those bacteria can live in your guts and make their toxin instead of these food poisoning ones that make their toxin before you eat it. | 54 |
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[The Matrix] When a program for something like martial-arts or piloting a helicopter is uploaded into your brain, it's in your brain... right? So technically can you still utilize those skills outside of the matrix? | 109 | Yes and no. You can't use the program, that's a part of your avatar inside the matrix. However, if you got the chance to actually pilot a helicopter, you would remember doing so, and while your muscle memory might not be up to scratch, you'd at least know what switches to switch, what the helicopter should feel and sound like, which are all things that people usually need practice to learn. You might also have some instinctual responses if you got enough practice. It's different from a simulator because your body doesn't know what to do, but your mind does. | 102 |
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Will turbulence experienced through flight ever be a thing of the past? How will it be avoided if so? | 53 | Turbulence is a result of flying through unstable air and the best way to avoid it is to fly higher. One day we might have sub orbital space planes which fly very fast and 40-60km up which would experience very little turbulence while at cruising altitude. There would still always be a chance of turbulence when travelling through the stratosphere and troposphere during accent and decent phases.
In short, no there is no way to avoid turbulence as long as you fly through something inherently unstable like our lower atmosphere.
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Advice for Programming Birthday-Suprise for my Fiancée | Hi All! I'm (M33) a non-native English speaker, on a throwaway account because I don't want my fiancée (F30) to find out.
I have an idea for her birthday gift but would like your input on it because I don't even know how to code. (She does it for a living). My idea was to create a self-designed apron for the kitchen, we both love to cook and I think it would be a great idea to give her a (high-quality, etc.) personal apron.
I researched some programming 'rules' and created the following code (see below). I wonder if you could all give me some input, tips and tricks, and creativity for this code and tell me if it is funny or not:
​
/Define Hunger
{Lonely Mouth,
Growling Stomach}
/If Lonely Mouth is
TRUE
/If Growling Stomach is
TRUE
/Then it is time to
COOK
The format is partially done this way because of the size of the apron :) Thank you so much for your advice! | 17 | How about making it a bit more so that it looks like code syntax?
void Hunger (Mood, Stomach)
{
if (Mood=="Grumpy")
{
if (Stomach=="Growling")
{
Food = TimeToCook() ;
Eat (Food) ;
Mood = "Happy" ;
Stomach = "Full" ;
//TODO later CleanKitchen()
}
}
}
This is supposed to be code(function) that takes your "mood" and "stomach". It checks if your mood is grumpy and if your stomach is growling. If they are true, you make "Food" since it's TimeToCook and then you "Eat" it. Then, we change your mood and stomach to "Happy" and "Full". The last part is like a side note in the code called a comment, saying that the code to clean the kitchen hasn't been written, maybe we can do that later ;)
Never thought I'd write code for someone's apron, but here we are. Cheers! | 23 |
CMV: corporations should be required to pay for the disposal of their products. | If companies were explicitly responsible for the disposal costs associated with their products it would incentivize the production of items that are more reusable and less costly to dispose of. It would also help ensure products are correctly disposed of, since there would be dedicated funds.
The current system unfairly shifts the blame the the consumer, is much less effective. The debate about plastic straws is a great example. It puts extra pressure on people with disabilities, addresses such a small part of the problem of plastic waste, and has turned into a status symbol in many ways.
Yes, this would increase the cost to consumers, but consumers already pay this cost indirectly through taxes and degraded resources.
Edit: logistically, I'm thinking something similar to the the carbon cap and trade market. Disposal cost would be set aside at the beginning of the product's life, regardless of when our where it gets disposed of.
I'm not saying you should mail your garbage back to whoever you bought it from. That's dumb. The money might not even go directly to disposal of that type of product, but pubic public outreach, or research, or clean up. | 292 | If you want to use cost to incentivize the correct disposal of waste (I good idea IMHO) shouldn’t that cost be applied to the ones who make the choice of disposal (ie the consumer)?
The problem with charging the producer for waste disposal is that the cost of disposal depends on how the consumer handles the waste they produce. It makes the determination of the cost of disposal at the manufacture level completely arbitrary. The manufacturer can contribute, eg by using recyclable materials, but the consumer needs to have an incentive to play their role in the cycle.
To make this work you need to put some cost incentive on the consumer. An example of this is the deposit refund scheme for drink bottles. The consumer pays for the waste they produce in the bottle deposit added to the price of the drink and can get it back by doing the ‘right’ thing by returning the bottle to a recycler. | 16 |
[DC] Does the Green Lantern Corps have the equivalent of a non-interference protocol or Prime Directive? Would the Guardians recognise the sovereignty of civilizations whose leaders ask they be left alone no matter how evil or unjust they might be? | 81 | Pretty sure those those guys are all about interfering whenever the heck the feel like it. After all their three powers are being super-condescendingly arrogant, being almost always wrong, and Making IT Worse. | 78 |
|
Why do price ceilings cause shortages if each individual unit of a product sold still makes a profit? | [https://imgur.com/a/mLF4fTm](https://imgur.com/a/mLF4fTm)
If you are making on a profit on each individual unit of ice cream, why would a company sell less of it? The only way I can think of this happening is if the price of the materials or labor gets more expensive as you make more ice cream, but isn't the opposite actually true (economies of scale)?
This isn't the first time I've learned this material, but I never understand it. | 20 | Cuz only the folks that can make a profit at that price point sell it. And they might not be able to expand their production and still make a profit.
​
Say there are 20 folks that can make ice cream. 10 of them break even at 5 bucks a pint, the others at 7 bucks a pint. If the price is set to 5 bucks, 10 of those folks won't even bother.
​
The other 10, say they produce until their current inputs are maxed out and there is still a shortage. They would have to expand their factories, which is expensive so they won't make a profit for a long time (if ever) with the price ceiling so they don't bother. Or they have to buy more raw materials (milk, sugar, labor, w/e), and past a certain point their demand drives up the cost of raw materials, which means they don't as much/any profit. Either way past a certain point they don't bother.
​
Edit: About economies of scale, eventually you start competing with other industries that buy those inputs which will drive up the price. The ice cream company bids against the cookie company for sugar for example. | 17 |
[Green Lantern] The rings all happen to only represent emotions that humans feel. Does the series address this in any way? | For example there is no ring for an emotion only aliens feel. There does not seem to be a problem translating emotions across species (ie hate is a positive thing for this species of alien so it translates to compassion). There also seems to be no issue with magnitude. Like this alien feels incomprehensible amount of hate or fear compared to humans so his ring would have explosive power from something as inconsequential as dropping a salt shaker accidentally.
 
Are humans regarded as the prodigies of the rings for being able to feel them all or are they perhaps looked at as the most unstable because they can feel them all at once? Do other alien's feel overlooked by whatever made the ring for this very reason?
 
On a somewhat related note why don't yellow lantern users just find the tiniest alien species with short lives and breed them to be able to sustain near constant fear for their lifetime? Or you know get a pack of [these guys](https://i.ytimg.com/vi/7_bl9L2XPPI/maxresdefault.jpg) in their pocket? | 32 | Emotion is a cosmological constant in DC. The variation in feelings and perspective you’re suggesting doesn’t exist. Separate species may express their emotions differently, but the emotions themselves are constant. | 52 |
What are "cosmic rays"? | I know space travel is hazardous to astronauts due to long term exposure to "cosmic rays".... but what are they? Are they part of the electro-magnetic spectrum, like gamma rays?
Also, I've read that they are difficult to shield against... but an insulating layer of water in a space ship's hull could provide protection... is that true? If so, why water and not another (less bulky) substance?
**Edit**: Thanks, r/askscience! | 19 | They are highly energetic charged particles which originate outside our solar system. They are primarily protons.
When they collide with atomic nuclei in the atmosphere, they produce showers of other particles via nuclear spallation and other high-energy reactions.
There are muons traveling through your body right now which were produced as a result of these showers. For example, a high energy proton could collide with a ^(14)N nucleus, producing a shower of pions. The charged pions can then decay into muons, which travel toward the ground at a speed very close to c.
Time dilation extends the lifetime of these muons in the laboratory frame so that they live long enough to reach us. They are traveling through you right now, losing a very small amount of energy every once in a while.
It's extremely hard to shield against these muons. But they don't significantly harm us, and they can be pretty useful (for calibrating detectors, for example). | 16 |
ELI5: How does gravity make time slow down? | Edit: So I asked this question last night on a whim, because I was curious, and I woke up to an astounding number of notifications, and an extra 5000 karma @___________@
I've tried to go through and read as many responses as I can, because holy shit this is so damn interesting, but I'm sure I'll miss a few.
***Thank you*** to everyone who has come here with something to explain, ask, add, or correct. I feel like I've learned a lot about something I've always loved, but had trouble understanding because, hell, I ain't no physicist :)
Edit 2: To elaborate. Many are saying things like time is a constant and cannot slow, and while that might be true, for the layman, the question being truly asked is how does gravity have an affect on how time is perceived, and of course, all the shenanigans that come with such phenomena.
I would also like to say, as much as I, and others, appreciate the answers and discussion happening, keep in mind that the goal is to explain a concept simply, however possible, right? Getting into semantics about what kind of relativity something falls under, while interesting and even auxiliary, is somewhat superfluous in trying to grasp the simpler details. Of course, input is appreciated, but don't go too far out of your own way if you don't need to! | 18,684 | Speed is equal to distance over time.
Gravity increases the distance light travels as it curves space.
The speed of light is constant no matter where you are and no matter how fast you're going.
So, if the speed of light is fixed and the distance increases due to gravity then time has to slow to make sure the equation still balances.
The more gravity there is the more space is curved and the slower time moves.
Edit - thank you very much to u/Undead_Kau, u/GamerKingFaiz and an anonymous user for the gold, it's very much appreciated. | 18,354 |
ELI5:Why do firefighters "make it rain" on a fire instead of pointing the hose at the ground or directly into the fire? | 50 | What they are trying to do is prevent the area immediately next to where the fire is from catching fire. By doing this (in theory) the fire will have nowhere to go and eventually use up the fuel that is currently on fire and extinguish itself.
The "make it rain" approach is common because it starves the fire of both heat and oxygen (the water vapour displaces the oxygen in the air) | 41 |
|
CMV: Developing space infrastructure should be a higher priority than trying to colonize Mars | There seems to be a lot of romance around the idea of colonizing Mars and I hope that someday there is a Martian colony. But first we need better space infrastructure. That means more efficient ways to launch and reuse rockets like SpaceX is developing. More needs to be done to develop Earth orbit capabilities, and perhaps a Moon base to develop the the first off world manufacturing and intermediate base for exploring further out. We also need to develop the infrastructure that will enable us to start doing asteroid mining. That’s primarily so that we don’t need to launch as much material into orbit to build things in space. What do you think? | 69 | I work in the software development industry, and there is a recurring debate on this very issue.
On the one hand, new projects are sexy. They attract investors and customers. They have goals that are easy to define and market.
On the other hand, infrastructure projects can help the "sexy" projects move faster in the future. They provide a network of support that, in theory, should make all future goals cheaper and easier to achieve.
There is a hidden downside of infrastructure projects, however. First, humans aren't good at predicting the future. We often build infrastructure to address problems that never materialize. Second, we often build infrastructure and then discover that other technology has advanced in ways that render our infrastructure irrelevant.
In software development, as in space technology and most other pursuits, it is often most efficient to develop infrastructure *alongside* the sexy projects on an as-needed basis to ensure that no waste is produced. | 18 |
ELI5: Why is rolling your eyes a universal sign of being annoyed? | 21 | It isn't a universal expression of annoyance, though. In fact only since the 1930s or 40s did it start to have that connotation in the U.S. Watch old movies, and you'll see it was an expression of wry amusement. (Look at even older movies and it was a "come hither" gesture!) It evolved from amusement to the dismissive "oh, brother" or "oh, please" around WWII. From dismissive to contemptuous was a short step. The meaning of the gesture is purely cultural.
There aren't many studies specifically on it, but eye-rolling is not an automatic gesture. It's consciously done.
Many cultures do use looking-away gestures to indicate dismissiveness or rejection. But not all involve the eye roll.
The homogenizing influence of mass media is starting to spread this one, though. | 16 |
|
If I keep my chapped and cracked lips shut, will they heal together? | 29 | Yes. Skin cells are dumb. Cell adhesion complexes in general are dumb. If you managed to hold them together close enough while they healed, you could get them to grow together. But the contacts would likely not be very strong, and you could probably pull them apart with very little force. Incidentally, the same phenomenon is at work when your unused muscles get "stiff" and "knotted" - this is from overlapping muscles that should move smoothly across each other forming cell adhesion contacts through proximity. These may be worked out mechanically by massaging, etc. | 26 |
|
ELI5: Why do movies usually take 2-3 years to produce while similar quality shows like House of Cards can be produced annually? | 258 | House of Cards *did* take 2-3 years to produce from writing to casting to shooting. It is important to note that Netflix ordered two seasons of 13 episodes each from the get-go. They didn't film one season, leave, and then suddenly get the call for another season and then scramble and put it together all in one year, it was already planned that way, which makes it far more efficient. Filming for Season 2 was literally a few weeks after Season 1's release.
Occasionally even movies with similar cast and crew have a similar trend. Lord of the Rings had a yearly release due to knowing how many films they were going to make but the infrastructure to bring about the first one took far longer (and even then, the filming process for the trilogy was insane logistically). | 150 |
|
CMV: The notion that you would be able to defend yourself from a corrupt government is irrational. | Like the title says, many pro-gun advocates make the argument that they own firearms to defend themselves from a corrupt government (in this case, the U.S.), but don't realize they would be far from threatening to an organized fighting force with military equipment (national guard, army, etc.) This argument would be applicable in colonial America where most fighting forces were still in development and consisted mainly of militias. The point is that your 9mm won't be able to defend against coordination, a chain of command, and fully automatic weapons. | 30 | It's largely a matter of what you're willing to give up.
If a dissident guerilla group of terrorists decides to wage a long campaign against the government, hitting soft targets and retreating into sewers and basically waging a campaign of assassination and murder - well, most of them are going to die. They're going to get killed by soldiers.
But these campaigns, over the long term, have a tendency to destabilize a government and cause it, if not to fall entirely, than to come to the table ready to negotiate.
If you're willing to die in the hopes that your grandchildren might have a better future (because your children sure as fuck won't), an armed insurrection can indeed be effective. | 27 |
CMV: While I believe tattoos can serve significant personal meaning, a large number of piercings simply suggests a generally lower amount of self-esteem. | I'm coming into this suggesting that my evidence may be mainly anecdotal (not to mention with a pretty malleable perspective), so this might be an easy one for you guys, but it still bothers me.
I simply can't understand the psychology behind desiring a large number of piercings in the face and other body parts. There's a certain number of piercings I can understand (due to fashionable trends in society) -- ears, belly button, maybe a nose. Where's the line? No exact idea. But other than that, when I see a person [like our lovely Jody in Pulp Fiction](http://3.bp.blogspot.com/-0JxRKIDt5Wg/TVRxwVstAYI/AAAAAAAAAQ0/MdknphmOGnM/s1600/pulpfiction00001.png) who has a face filled with piercings, I can't help but think they likely have the desire to cover up insecurities about their looks by distracting the eye from them (or they are desperately trying to get attention). Most people I know who have heavy piercings confirm this idea; I find their personalities to be attention-seeking, insecure, and many times very hostile to others for ridiculous reasons.
I certainly hope someone can explain the desire for heavy piercings. I know it all comes down to personal choice and that's fine but there's always implications for the things we decide to change about ourselves, and I don't really see the point of heavy piercings other than a need to stand out and a deep-rooted insecurity.
EDIT: Took another fallacious argument to make me realize how fallacious my argument was. ∆.
_____
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I personally can't understand the psychology behind going to a Taylor Swift concert, but that doesn't mean there is something wrong with her fans.
It's a hobby, there is no need to regard it as more than an (unusual) hobby. | 15 |
[The Boys] Is Billy Butcher actually English? | As an English person his accent to me is such a caricature of a cockney it's insane. As far as I remember he never mentions anything about his English past. Did some trauma from his past make him snap into this cockney character? | 42 | He might have learned to exadgerate his accent in the english military, or he might have spent so much time in one intelligence program or another under a cover that he lost his natural accent. He is from Britain, but time spent in the melting pot of the military industrial complex can warp someone's language pretty strongly.
that said, his accent is a tool to make people underestimate him, and he wields itas he wields anything - violently and with as much force as he thinks is necessary. | 43 |
ELI5: How does eating high fibre food prevent us from getting constipation? | 32 | You can't digest/break down fibre. It stays in your gut. When things stay in your gut, it tends to pull water in because the water can't be absorbed into your intestinal wall. That water acts to soften up your poop, making it pass along easier. | 29 |
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ELI5: Monte Carlo simulations. | I guess I just don't understand how they are done. | 36 | Suppose you are sharing a room with your brother. The left side is yours, the right side is his. You draw a line on the floor to mark them, but you think it should be moved more to the right and so you start quarreling. You do not have a measuring tape (and besides, since the room is not a rectangle it's hard to measure), and you want to know if the division of the room is fair. What do you do?
Well, some clever people came up with a way to see if the line is in the middle, and all you need is a bouncy ball. What you do is, you throw the bouncy ball against a wall (really hard, so that it bounces against the floor and walls multiple times) and see where it ends up. You do this a lot of times and each times you note whether the ball ends up on your side or his side. If you keep doing this, and the room is divided fairly, the balls should land in each side of the room about the same time. | 60 |
ELI5: Why don't Federal programs have a small trial-run like "America Works" had in 'House of Cards'? | You'd think with all the fighting in Washington, you'd think any idea could be trial run on a small scale to collect data on whether or not to unroll the programs nationwide. | 33 | They frequently do. Either the government will run a pilot program to test it out, or the program will have been tested in a state (or states) prior to national adoption.
For example the Affordable Care Act ("Obamacare") tried in Massachusetts for years before it was adopted at the Federal level (and the success of that program on the state level is part of why it was adopted at the national level). As an example of national pilot programs, you can look to Head Start - which is constantly running pilot programs to expand services or test new ways of providing services prior to national roll-out. | 22 |
ELI5: why do bats hang upside down. | 25 | Hanging from the ceiling provides a more optimal position to escape harm should a predator or some other danger come along, as they can simply drop and spread their wings to be airborne instead of needing time to take off from the ground.
Also, the ceiling of a cave is less likely to encounter predators than the floor, so sleeping while hanging from the ceiling keeps them safer. | 27 |
|
[Star Wars] Are snowtroopers, sandtroopers etc specialised infantry divisions that are only deployed to planets with specific conditions or are they regular stormtroopers who are fitted for whatever the conditions demand? | Side question. If they are specialised divisions are they considered more elite and harder to be accepted into? | 76 | They're normal troopers in specialised armours. The sandtroopers deployed searching for R2-D2 and C-3PO were dispatched from the Devastator. It'd be fairly silly for Star Destroyers to carry specialised divisions of troops for every possible environment as most of them would rarely see action and be useless. Much better to have an adaptable fighting force in far greater numbers.
The 501st lead the assault on Echo base, as well as the Tantive IV, they were the same soldiers in different equipment. | 62 |
CMV: The Humans are the good guys in Starship Troopers | I know the symbolism and what it is supposed to mean but it just doesn't seem to add up symbolically. It doesn't seem to make a good case for what it intends to satirize and instead seems to further (unintentionally) glorify it.
I find it odd that the bugs are often cited as good, or victims. They have actively conquered countless other sections of space and spread through violence and spore like travel to other planets before even coming in contact with humans. They have a likely as unjust society if not worse than the human society as they subscribe a caste system and bugs likely don't even get a chance to dissent or live a certain way as they are trapped in a hive mind. They attacked first. These are creatures incapable of complex thought which are led by a drive for violence and complete xenophobia to the point of exterminating any other complex life, especially that perceived as lesser.
Meanwhile the humans had generally respected and given the bugs space but would eventually find them to be too large a threat to just leave to claim more human lives needlessly. (Minus the fact that the fighting of these born and raised apex predator bugs costs manpower and casualties.)
The humans seem to be justified, it would seem and not like the satirical joke/parody the creator tried to make them out as and instead inadvertently argues for the thing it was arguing against. | 15 | The movie is a very straightforward critique of American fascism, and the bugs are presented as basically neutral.
The meteor "attack" on Buenos Aires was only **blamed** on the bugs, never actually attributed to them. It's implied in the movie that it's a Reichstag Fire moment, where the government allowed/caused it because they needed popular support for attacking the bugs.
The only evidence that the bugs have "conquered" the rest of the planet is from the fascist Earth government. Just replace the word "bug" with "jew" and pretend it's Nazi propaganda. The more accurate reading is that the government is lying about the bugs "conquering' anything, and that their presence across the galaxy isn't a militaristic threat. You have no idea what their society is like - and even if it were a caste-based system, that isn't justification for genocide.
The final moment of the movie is probably the strongest evidence that the humans are the bad guys. For the whole movie, you've been told that bugs are insensate murdering machines. One person in the movie is even offended at the idea that bugs can think. But in the final moments of the movie, Neil Patrick Harris learns that the captured queen bug is "afraid."
At that moment, you're invited to think about the invasion from the bug's point of view, and you realize that - to this bug - she was just chilling in her home, and then these invaders showed up, killed off hundreds of her family, and now they're surrounding her. The humans are exactly what they think the bugs are.
And instead of this being an enormous moral reckoning for the troops - who were supposed to believe that bugs are just murdering machines, incapable of fear - they all cheer. Cuz they're happy it's afraid. They don't even realize that they're the bad guys. It's a joke. | 27 |
ELI5: Why do people claim to know how many illegal immigrants are in the United States? | If someone is illegal, there's no documentation on them, right? I realize the numbers are estimates, but I can't imagine how these estimations are even close if there isn't any hard data. | 40 | There are multiple ways to estimate the illegal population. These include economic impact, public service usage, population samples, the census, and migration tracking.
Economic impact looks at levels of spending and the flow of money to determine the population involved in the economy. We can compare this to the documentation we do have to find who is missing. We can also use this method to determine the black market size and under the table economy sizes, these are how illegal immigrants are paid.
We can also use data on public service usage to estimate size. Hospital visits, public school enrollment, and arrests all alow use to sample the population.
Population samples, the census, and migration tracking are forms of mass and local data collection taken on by the government. The data collected can be compared to know populations and communities to adjust for errors such as non-reporting by the population themselves. | 14 |
[Marvel] How do Daredevil and She-hulk still practice law without a secret identity? | The BAR association can't ignore the fact that those two are publicly known for going out at night and beating people up ignoring the rule of law. Why havent they lost their law licenses? | 15 | Mat Murdok isn't publicly known as a super hero and Jennifer Walters is not a super hero. She has been attacked a few times and has helped fight terrorists a few times but she isn't a super hero she is a lawyer with a medical condition. | 41 |
[generic or classical sci-fi] How to describe dimensionality in other terms? | A popular way to reference other universes in less technical terms is to call them other dimensions, but this term has its own peculiarities that logicians love to make hay about.
"A dimension is just length, width, depth, or time," they may say. "How can you visit a whole other dimension like it was a separate universe?"
But if we start redefining things, the apparent contradictions will go away.
So what if a different term was used for the different axes of three-space?
A point in space simply exists, a singularity. A ray can emanate from it, but can only describe direction or length. Add a turn, and you define a flat two-space, length multiplied by width. Add a second turn, and you have a volume or three-space, length multiplied by width multiplied by depth. This plus time makes a spacetime, or a complete dimension. So how many turns? Technically three: length is the zeroth turn. A dimension has three turns emanating from a singularity. With a time arrow that three-space is allowed to have a past and a future, not simply a singularity of an eternal present. It is allowed to change and to experience entropy.
Most dimensions seem to share the same time arrow. You start in one diemsnion, travel to another and spend one hour there, then come back--one hour has also passed in the first. There are dimensions where time goes faster or slower, but these are rare.
Finally, some dimensions have a "3rd turn": hyperspace or subspace, an ethereal or shadow realm that corresponds to multiple frequencies or vibrations or energy levels of existence. Objects and creatures existing at different frequencies may slide through each other or be invisible to each other, but they are still existing in the same dimension of spacetime. And perhaps there are even more turns than these than we can dream of in this philosophy.
Thus: whenever a character or a narrator talks about dimensions as universes, they are talking about universes made of three (or more) turns plus a time arrow, might they not? | 21 | Take a potato and slice it thinly. Each thin slice would have a slightly different shape, different feel. You could take a thin slice and cut a hole in it, and the slices next to it would be unaffected. Now take all the slices and stack them back up so they're in the shape of the original potato. You can travel between the slices just by moving down the potato.
All you're doing is stepping between slices of the potato. | 10 |
[Star Trek]it's 2147 and you're a 24 yr old with an associate degree in engineering, your goal in life is to see as many planets as possible. Are you better off applying to star fleet and hoping you eventually end up on an NX ship, or are your chances better if you just sign onto a freighter crew? | 307 | At that time-prior to the Romulan War-United Earth Starfleet (UES) was still relatively small compared to its potential allies (Vulcans and Andorians). However, because it was small, most of its development was in line ships, rather than support ships.
The merchant fleet was far larger (though not nearly the size of the same Tellarite industry), but the “boomer” fleet was far slower than most of the UES’ line ships (including the NX “Enterprise” class). It could take many months and even years between ports of call, and if you served on a corporate ship, you probably found yourself on a pendulum or triangle route, limiting the scope of planets you’d be exposed to within say a 10 year period.
I’d say your best shot is Starfleet. Your drive to see new destinations mirrors that of the fleet. Even if you start off on a NV “Triton/Intrepid” class ship (limited in range), with stalwart career management, you should end up on one of the handful NX explorers by your 2nd or 3rd tour, with the leadership experience to be on landing parties. | 218 |
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Would a bullet in a vacuum travel in a straight line or a corkscrew patern? | I know that bullets move in a "corkscrew" pattern in the atmosphere, but is this due to interactions with the air or just centrifugal force alone? To put it another way, would space guns be better off with or without barrel rifling?
Edit: *pattern | 20 | Rifling is mainly for aerodynamic stability, to prevent the bullet from tumbling. It doesn't really make the bullet travel in a corkscrew pattern, though. The bullet still travels in a straight line, but it spins around its long axis. | 12 |
ELI5: If Communism promotes social equality, why is there such a big poverty gap in China? | Recently learning about different economic systems and this question came to mind. | 44 | The People's Republic of China has been most communist in name only. It is communist only in the sense of how the political party functions, and has had no responsibility to redistribute wealth since the 1990's. China has a capitalist economy that is state-driven, as opposed to the market-driven economies of the West.
| 43 |
Are living fossils like the Horseshoe Crab evolutionary dead ends? | Since they haven't changed in millions of years does that mean their's no room for improvement or is it their mating practices that keep them the same? | 143 | This question stems from a misunderstanding of what evolution is. Evolution is not a journey, a ladder or a race - there is no end goal or pre-destined 'better' point which beings are evolving into. Every species which isn't endangered or extinct is perfectly suited to its own niche.
Evolution is a reaction to changing pressures in the environment. If there is nothing that requires a different trait (for example if a horseshoe crab with longer legs survives no better than one with regular legs) then there is no evolutionary pressure on the species as a whole, as the regular individuals are just as likely to survive and procreate.
Basically, the horseshoe crab is by its very existence evidence that it doesn't need to change. It's survived in its ecological niche for millions of years and that's it.
| 200 |
[General] So I found a genie in a bottle and he said I can have three wishes. My first wish was for unlimited wishes. How does the genie handle this? | 23 | Genies as depicted in the Arabian Nights aren't wish factories, they are immortal semi-demonic giants that may grant wishes if the circumstances are correct. The OG legend of a genie being freed and offering wishes is that the genie was so happy about being freed that he offered his savior the wishes.
If he was giving you these wishes because he was happy you freed him from the bottle, and then you take advantage of the boon by wishing for more wishes, a traditional genie will probably just kill you for trying to take advantage of his kindness. | 63 |
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In the Pale Blue Dot picture, why is the Earth the only relatively bright object? Where is the Sun and other planets and why aren't they visible? | [Pale Blue Dot](http://i.imgur.com/3iPkXHq.png) | 76 | Well, if you'd had the sun in the frame, the earth would be washed out, so obviously, you've got to shoot the earth and not the sun. also, objects in space are really far apart from one another. it's rare that you have two planets in the evening sky close enough to view together in a scope.
so to answer your question, other objects in the solar system are not in the frame of the photograph. | 52 |
ELI5:In our dreams, how are the people we have never seen or interacted with before conjured up? | I feel like I interact with humanoids when I remember a dream with someone I have never met before. | 32 | If you walk down a typical shopping street or visit a cinema or restaurant, you see hundreds of faces in the space of an hour that you'll never remember you saw. If you go to a music festival or sports event you'll see thousands that you'll never remember you saw. Even if you never leave your house and only watch TV, over the course of a few shows you'll see hundreds of extras whom you'll not consciously remember. Your eyes are pulling in unfathomable amounts of data all the time, your brain only selectively recalls some because if it recalled all you would be overstimulated to the point of not being able to function normally, but in dreams those bits and pieces can surface. | 21 |
[Harry Potter] How would things go if Voldemort and the Death-eaters chose to conquer the muggle world before laying siege to the Wizarding world? | 53 | Conquering the Muggle world would be a relatively simple matter for the Dark Lord. Apparating into the bedchambers of world leaders and Imperiusing them in their sleep would be a fairly trivial task for someone like Voldemort.
The thing is, though, Voldemort has no desire to conquer the Muggle world. To Voldemort and his followers, Muggles are a lesser form of life, one that is to be used when convenient, ignored when unneded, and slaughtered when the whim strikes. He has no more desire to take over the Muggle world than a human would want to take over a forest and rule over the woodland creatures as their king. Conquer the Muggles? What's the point? | 64 |
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[Star Wars] I understand that the rebels are battling the Empire, but why? What was the issue with the Empire running the universe? High taxes, too conservative, too authoritarian? | Maybe it’s explained in one of the movies, but I must have missed it. It’s clear they are pretty brutal and authoritarian, but so are most countries when dealing with violent rebels. | 811 | Well, there are a few little things. Just minor quibbles, you know.
The dismantling of all forms of democratic representation. The government being under the control of a ruthless dictator-for-life. The use of tactics like orbital bombardment on civilian populations. The strip-mining of worlds down to the mantle to fuel the galactic war machine. The reduction of non-human populations to second-class citizens on their own homeworlds. The mass use of slavery. The Lasan massacre. The Geonosian genocide. The replacement of traditional bureaucracy with the constant threat of planetary annihilation.
They aren't just brutal to the rebels, they're brutal to everyone. | 1,172 |
ELI5: Why is it nearly impossible to breathe when strong winds hits your face? | For example, when you lean out from the car window when driving, or when it's just storming outside, it feels like the throat is "closing" and makes it really hard to take a breath. | 35 | So when air (a gaseous substance) is in motion it creates a low pressure zone, as opposed to stagnant air. Your lungs work by expanding and creating a low pressure zone for the surrounding air to push into and then by compressing and creating a high pressure zone the air in your lungs is pushed back into the lower pressure surrounding air. When you try and breath in a low pressure environment, like your head out the window, you are fighting a very low pressure environment with the comparatively high pressure air in your lungs. in essence 'sucking' the air out of your lungs. Think of it like the opposite of when you are blowing up a balloon, its harder to blow more air when the balloon is full. as opposed to when it has less air in it. (ignoring the initial push to get the rubber to expand at the very beginning) | 18 |
ELI5: How do we know that someone "died in their sleep"? Can we tell they were asleep when they died? | 130 | Not an expert but took a class in forensic medicine. You look at the surroundings. If you see the nightlamp beside the bed toppled or pillow/blanket was thrown violently around, more likely than not the person did not die in their sleep | 143 |
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[ASoIaF/GoT] Who was the better Hand of the King: Tyrion Lannister or Tywin Lannister? | 15 | Tywin. Not that Tyrion was a bad hand, but Tywin faced way, way less opposition to him doing his job because of how much everyone respects and fears him. Plus he has way more experience in the job than Tyrion | 31 |
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What is the unit of measurement for gravitational waves? | Now that we have found einsteins gravitational waves; I am writing a bit of science fiction which is centered around space-fold/warp technology. I am curious, now that Einsteins gravitational waves have been proven; what is the unit of measurement by which they are measured? Also are these gravitational waves measurable in the electro-magnetic wave-length? I ask, because by this measure, wouldn't "warp" drives use wave-length to measure jumps? | 74 | The typical unit is strain h, which is dimensionless. It's the change in distance over the total distance (h=∆L/L). This is a very small number, as you might imagine, since gravitational waves are extremely hard to detect. For LIGO, h was 1 x 10^-21.
You may also want to consider the gravitational wave frequency, which was in the 10s to several 100s of Hz for LIGO. For other experiments, such as pulsar timing arrays, h is expected to be many orders of magnitude larger, but at frequencies much, much lower, so LIGO can't detect them. The frequencies are analogous to electromagnetic frequencies since gravitational waves propagate at the speed of light (i.e., the wavelengths are defined the same way).
| 16 |
[Star Wars] Was the Empire Sexist? | I'm curious if the Empire (either the military specifically or the broader political entity) was sexist. I don't recall ever seeing or reading of any instances where males are overtly favored, so I'm tempted to say not especially. On the flip side, there is a notable lack of females in the military (Captain Phasma notwithstanding). While this isn't necessarily an indicator of systemic sexism in the Empire, it got me thinking. Was this an issue for the Empire? We all know they were quite xenophobic, but is it possible they were lightyears ahead in the area of sex and gender issues? | 15 | The Empire actually has a number of female in a number of important positions. For instance Ryloth was under the control of a female moff who was mostly ineffective because of her grief for her lost wife and having her number 2 run things. There have been a number of female governors as well as female offiecers in the Navy. But as /u/VicariouslyHuman noted there are less females in combat roles, tho the Stormtrooper Corps does include female troopers. | 28 |
For every poisonous item on Earth, do we know it is poisonous because someone tried to consume it and died? Or is there a way to know a substance is lethal without the trial and error? | 90 | We have the Universal Edibility Test, and it was probably used by people of the past as well.
Here are the basic steps:
1. Separate the plant into its various parts—roots, stems, leaves, buds, and flowers. Focus on only one piece of the plant at a time.
2. Smell it. A strong, unpleasant odor is a bad sign.
3. Test for contact poisoning by placing a piece of the plant on your inner elbow or wrist for a few minutes. If your skin burns, itches, feels numb, or breaks out in a rash, don’t eat the plant.
4. If the plant passes the skin test, prepare a small portion the way you plan to eat it (boiling is always a good bet).
5. Before taking a bite, touch the plant to your lips to test for burning or itching. If there’s no reaction after 15 minutes, take a small bite, chew it, and hold it in your mouth for 15 minutes. If the plant tastes very bitter or soapy, spit it out.
6. If there’s no reaction in your mouth, swallow the bite and wait several hours. If there’s no ill effect, you can assume this part of the plant is edible. Repeat the test for other parts of the plant; some plants have both edible and inedible parts. | 88 |
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CMV: Stereotyping is often logical and a perfectly normal application of human reasoning | Stereotypes are perpetuated because there is some truth to them. Bad or absolutely false stereotypes are rarely common, because failure is like natural selection. People use stereotypes as a short cut to knowledge, because we almost never have all the facts to make an informed choice. So people fill in the gaps, sometimes that will prove to be incorrect, but if it is more often correct than incorrect it is providing potentially valuable data.
Example, if you are walking down a dark alley and some guys are following you, there are a wide variety of valid stereotypes to approximate how much danger you may be in. It is not required for them to be always right to be useful. A guy covered in tattoos may be completely safe, but is he as safe as someone without any? No, of course not. And if you think so, you're simply misinformed or willfully ignorant due to social avoidability bias. If they're a bunch of young black guys, same thing, it's just more socially unacceptable to think such a thing. Are they women laughing together? No reasonable danger.
So people and society should not be made to feel bad about applying simple logic. Until crime metrics change, stereotyping is here to stay. There is no way to effectively eliminate it without solving why the stereotype is applied. I understand it is demeaning and insulting to be stereotyped, but your feelings don't really change the facts. In the case of covering your body in tattoos, it was actually a choice you made, which removes all moral authority to be offended in the least.
Studies have been done which indicate that there is a positive correlation between intelligence and stereotyping, however intelligent people are quicker at reversing a stereotype that they find unhelpful or invalid. | 46 | There is a subtle semantic distinction here that may explain the issue.
Most of the things you mention are not stereotypes. Most of you the things you mention are *expectations* about certain groups. A stereotype is an *expression* of an expectation about a group, not the expectation itself. Acting on these expectations by treating people of different groups differently would be called *profiling*.
So for instance, by your example: a guy with tattoos mugging you would be falling into a stereotype about guys with tattoos, and someone writing a character of a mugger with tattoos into a book or TV show would be *stereotyping* people with tattoos. Being scared of being alone in an alleyway with someone with tattoos would just be an expectation you have about that group, and acting on that expectation by staying away would be profiling.
In general, we are against *stereotyping* (as in, creating representations of groups that fall heavily into the stereotypes about that group) because it tends to lead to the stereotypes being over-represented and giving people inaccurate probability assessment. For instance, yes, the average person with tattoos may be more likely to be a mugger than the average person without tattoos; however, the *vast, vast majority* of people with tattoos are not muggers, yet stereotyping may cause 80% of media representations of fictional people with tattoos to be written as muggers, giving people inaccurate expectations about their relative peril. The same s true for stereotypes about minorities, women, men, white people, poor people, rich people, etc.
To the extent that your *expectations* are actually accurate, there's nothing wrong with holding them and using them to inform your actions. However, the reason many people are against *profiling* is because very many of the expectations people hold are provably inaccurate due to stereotyping in the media causing them to overestimate the prevalence of the stereotyped traits.
So, basically: most of what you speak in favor of is either expectations or profiling. In theory there *is* nothing wrong with those things if you do them accurately, but most people do them inaccurately *because* of widespread stereotyping. Widespread stereotyping is bad*because* it gives people inaccurate expectations which leads to improper use of profiling, thus screwing up the entire system. | 13 |
CMV: Sauce makes the meal, not noodle | I don't like spaghetti. I never have. When I tell people this, they start asking me if I like other noodle dishes with tomato sauce, as if it is the physical noodle I have a problem with, not the dish as a whole.
While I am aware different noodles make different titled dishes, I believe they are all basically the same thing.
1) All noodles taste the same (unless specifically supposed to tasted different).
2) Putting spaghetti sauce on spaghetti noodles is the same thing as putting that sauce on bow ties, even if they technically have different names.
3) To the layperson, there is no need to differentiate between dishes when you can say "I ate spaghetti" or "I ate Alfredo" no matter what noodles you use.
4) To specify that you didn't have spaghetti, but Rotini with Ragu Tomato, Garlic, and Onion Sauce is pretentious and more effort than saying you had spaghetti.
Edit: Alright, in my head, the jury is still out on whether or not lasagna is still lasagna without the noodle. It may be the dish that changes my view, but let me sleep on it.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | 37 | I disagree. The different shapes and sizes of pasta hold sauce differently, changing the ratio of sauce to noodle greatly. If you have a heavy Alfredo and put it on a heavier pasta like fettuccini, the ratio is perfect. If you put that sauce on Angel hair, you have a nasty bowl of butter, cream and garlic. In reverse, if you have a light sauce like chopped fresh tomato, caper and olive oil, it's perfect on angel hair or bow ties, but on a linguine noodle it will taste like oily paste. | 20 |
[Rick & Morty]what happened to Rick that made him loose his contempt of authority so much he became a Cop? Why does the Citidel even bother policing its slums? | 41 | He probably did it because he cares for Morty and most "criminals" appeared to be Morty.
Also remember (according to Evil Morty/Rick) Ricks can be categorized on a moral spectrum and "our" Rick is on the pretty "evil" side, at least according to Evil Morty. | 59 |
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[Star Wars] What did people expect to do after the Clone Wars if their side won? Did General Grievous have a retirement plan? | 26 | There was already a government in place for the CIS. Dooku was essentially the Chancellor of the Separatist Senate, each system in their senate had similar powers to the Republic Senate, the primary difference is they believed it was far less corrupt and was not as stagnant as the Republic had become.
That wasn’t the case obviously, because the primary forces of corruption in the Republic had a huge hand in shaping the Separatist government. So they probably thought they’d just live as a rival power to the Republic, and that likely over time more systems would join them, leading to the eventual collapse of the Republic. Most Separatists weren’t the monsters that Dooku and Grievous were, they largely were kept in the dark about the actual actions of the war, fed propaganda about what was happening. They viewed Dooku as an honorable man who was a war hero helping preserve the integrity of a better galactic government. That’s also how Dooku viewed himself, but was planning to make the new Empire into the better galactic government.
The only time the average Separatist would see the war for themselves was when the Republic was the one invading their world, and the generals of the CIS were military crazed or the same corrupt figures those systems abandoned the Republic to get away from, so the only people who knew how atrocious their actions were, were corrupt, evil, or droids.
Dooku on the other hand, was well aware that Palpatine was the Dark Lord and believed when the Republic eventually won out, he’d be given a position within the newly constituted Galactic Empire. I’m not sure how he though that would work after waging a galaxy spanning war against what many would still consider the Republic, but that’s what he thought.
Grievous did not have a retirement plan, he was content killing Jedi, he didn’t have much greater political ambitions or anything. He hated the Jedi and enjoyed, as much as he can be called to have enjoyed anything, killing them. He was not a Sith but his hatred for the Jedi seemed to rival if not surpass most of the Dark Side force users we see. I’m not sure if he ever thought about what would happen if they were all destroyed. He was a warrior first, life after the war wasn’t his concern at the time. | 24 |
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ELI5: I recently got an electric toothbrush that has a UV chamber to kill germs. How can such a little blue light actually do anything? | 52 | The blue light is just what your eyes actually see. Ultraviolet light is beyond the range of human eyesight.
DNA, when exposed to UV light, will take damage. This will kill living cells. Shining bacteria in the stuff will kill them fairly quickly with minimal effort. | 51 |
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[Doctor Who/Marvel Comics] Could Reed Richards outsmart the Doctor from Doctor Who if they were both trying very hard to acheive their goal? | The Doctor is one of the smartest being in fiction. Hes fought very powerful beings on regular basis and won with mainly using his wits. He's considered the smartest person in his universe. Reed Richards is generally considered the smartest person scientifically/generally in the Marvel Universe. Let's say they both have somethign they want to acheive very badly could Reed outsmart the Doctor in any scenario? If there's no chance for Richard if they're both trying hard then make it a regular Doctor from Doctor Who. | 33 | The Doctor is very clever, and has a LOT of experience to draw from, but he often bumbles around and makes silly mistakes. While he's great at recovering from them, this shows that he isn't always paying enough attention.
Reed is always, always thinking at insane levels. He's built devices that shoot bombs that make universes, he literally helped re-engineer all of the multiverse, and he's way more dexterous and durable than the Doctor.
Given a problem the Doctor has encountered before, he probably has a tool or a plan ready to go to handle it. But, with an even start for a task requiring scientific creativity and innovation, Reed would probably outshine the Doctor. | 38 |
[Star Trek] How did the Klingons ever manage to build a spacefaring civilisation? | They have a strong tendency to be hot-headed and short-sighted, highly prone to violence, with little respect for intellectual pursuits, and leadership often being decided by melee combat.
This doesn't lend itself to the stable, intricate infrastructure and highly educated population required for that kind of advancement. So how did they work around that? | 534 | I’m gonna guess that not all Klingons are hot-head, rash types. There must be many individuals in the species who are more intelligent and less impulsive who make great engineers (and doctors, lawyers, priests, or their equivalents thereof), but they are simply underrepresented in the higher echelons of the military and government. Ergo, Starfleet (and, by proxy, the viewer) just doesn’t have much contact with the Klingon nerds. | 345 |
[Fantasy] What Faction in Fantasy uses magic the most effectively in Combat | I have always wondered what faction in all of fiction is best magic users in war. I’m talking about factions who can field entire armies of wizards and these wizards can actually use magic to its full potential | 20 | the black tower managed to rout an army of 40,000 aiel and 300 aiel channelers with just 200 or so of their own channelers.
they had maybe 7000 or so buddies helping them but really they did most of the work. | 43 |
ELI5: How do one-way mirrors work? | 18 | It's really just a window with tiny flakes of something reflective (Aluminuim or silver, for example) in it. When the other room has very bright lighting (and the observation room very dim) the window looks like a mirror because so large portion of the light comes reflected from your side. | 10 |
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Professor heavily failed (42%) a final paper which was build around other papers (90+%) | I took an English 201 class two quarters ago, the class was to write an argumentative essay. Throughout the quarter, we were tasked with writing assignments that we would later use to construct our final paper. The class briefly touched on argumentative essays, but quickly turned into a sociology class, with the professor spending lengths of time discussing politics and injustice. I'm a proud SJW who totally agrees theres some batshit crazy stuff in this world, but IMO it has no real place in an English 201 class and didnt really help towards the final goal. The class had over 3 weeks of canceled classes, two snow weeks and then the professor took an entire week off for an unknown reason. It was a very very sketchy class.
On the papers that led to the final, I scored over 90% on all of them. Part of our instruction was to essentially build the final with these papers, which I did. I ran my thesis past the professor and was given the go ahead to run with the idea. The prompt was Posthumanism and my argument was that while posthumanism is an interesting topic for science fiction, the effects it will have on my generation are very real and we must begin talking about it now before it's too late.
I finished the paper, checked what I thought were all the boxes and the rubric and submitted the essay.
To my dismay I saw that I was given the painfully low score of 42%!! Not a 70, not a 60, or even a 50, but a 42%. A number so specifically low, I thought I submitted the wrong paper at first.
Here's where I need your help: I sent an email to the professor asking for an explanation of where I fucked up. I made it very clear that I wasnt asking for a grade change, I simply wanted to begin the discussion of where I went wrong. No reply.
Having been left on seen for weeks, I emailed the English department head. He told me she was on leave and wouldnt be around, and that he would pass on my concerns. Months later - nothing. I see that professor is now off leave and currently teaching this quarter. I email the department head again- not even an acknowledgement of my second email.
What do I do now? My final grade was a C so TBH I dont care that much, but I feel kinda fucked over and no one is telling me why. Do I go to the dean? | 67 | Are office hours still a thing? If so, use them. Print your grades for the semester. Print your paper. Knock on door. If your prof isn't there for scheduled office hours, visit the chair's scheduled office hours.
Even given that paper was garbage worthy of a very solid F, you're entitled to feedback so you can improve | 90 |
[Halo] What is so important about Reach and why was it's fall a major event in history? | Was it a strategically important location or was it purely just the Covenant saying "look we can knock you on your ass even at your strongest fortresses" hoping to demoralize humanity? | 288 | Reach is at Earth's metaphorical doorstep, being 10.5 lightyears away from the Sol system. It was the nexus of the UNSC military command, Humanity's 2nd most populous colony, and a major producer for the UNSC's war material and recruits. It's titanium mines are the largest sources for humanity.
Its fall to the Covenant meant that the UNSC just lost its second most largest source of its logistics to rearm, resupply, and replace any lost military units. It meant that the Covenant were now closer to Earth and therefore closer to eradicating humanity. It meant that the UNSC could no longer mount offensive operations to reclaim any of the Outer Colonies either lost to the Covenant or went dark to avoid genocide.
Most importantly, the Fall of Reach was the impetus to Spartan John-117 and the *Pillar of Autumn* to discover the Forerunner Installation 04 and hence, the eventual victory of humanity over the Covenant. | 388 |
[MCU] Why is spiderman so hard to kill | I mean he heals fast but a single bullet though his brain would end him. So why hasn't this happened yet? He's not Deadpool or Wolverine he can't just regrow his brain. | 25 | Spider-Man knows the bullet is coming before you even fire your gun. His spider sense and instant reflexes make him hard to hit, let alone kill. He also has a genius level intelligence backing up his powers. | 56 |
[King Kong 2005] King Kong fought and killed three theropod dinosaurs. Are they Tyrannosaurus? | 34 | They're closely related descendants -- it has been 60 million+ years. Just as there were very similar relatives of crocodiles long before even the dinosaurs, they're not technically the same species, just very similar in appearance. | 25 |
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ELI5: Whats the difference between torque and horsepower? | 36 | Torque is the real, measurable force applied by the wheels to the road. (It's generated by the engine, then multiplied by the gearbox, final drive, and wheels.) Because it's applied by a circular wheel, it's measured in a combined unit of weight and length - pound-feet or newton-meters. A torque of one newton-meter applied to the road is equivalent to the force exerted on the wheel's hub by a weight of one newton, suspended horizontally from a stick that's one meter long and attached to the hub at the other end.
Horsepower is not a real measurable force - it is a mathematical construct that represents the engine's ability to accomplish work over time. The work is moving a certain weight (the car) across a certain distance over a certain time. You'll notice that compared to torque, time is now added. So if the weight of the car is the same, and the distance it's traveling is the same (let's say, a quarter mile), then to do the work over a shorter period of time - get there faster - you need to use up more horsepower.
Because there is a direct mechanical relationship between the engine's revs and the wheel revs, and therefore the car's actual speed, horsepower is calculated as torque multiplied by revs, and divided by a specific coefficient to account for the difference in units. Note: this is about engine torque, measured at the crankshaft. The torque at the wheels is a much larger figure, multiplied by the gearbox, final drive, and wheel circumference.
(A horsepower is around 745 watts, because James Watt calculated this as the power of a typical mining horse and used it for marketing, to show how many horses his engine could replace. In the standard system, one watt is the amount of work/energy that raises a weight of one newton to a height of one meter in one second.) | 31 |
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ELI5: Why do cars lose so much value the moment they’re driven for the first time? | 40 | If you decided you'd made a mistake and wanted to resell the car, do you think *anyone* would pay as much for it as you did? For that, they can go to the dealer and get a certifiably-new car. So you'll have to offer a discount, to make the deal worth considering. | 37 |
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If I am poor, and get a life threatening disease, do I just die? | So I am poor, not homeless, but no insurance (Other than obamacare). What happens if I develop cancer, am I just let die? Do I get sub par care? | 40 | In any civilised country, apart from America, you get treated, hopefully return to full health, then go home and forget about it. In America, generally, you get treated, hopefully return to full health, sell your home to pay for it. | 71 |
ELI5: Why does my poop smell fine to me, but it smells terrible to other people? | It usually smells okay for about 10 minutes, and then after than it starts to smell like anyone else's poop. Farts apply here as well. | 22 | Our sense of disgust is a way to stop us getting bad germs in to our bodies. This is why we don't drink gone off milk. Our noses are pretty good at telling us what is bad and what is good hence why we can smell whether food is good or bad.
This sense is triggered when smelling a fart. Only the understanding that it was your fart puts you at ease from being disgusted. Since if it came from you it's less likely to have germs that weren't in you already.
A great test for this is when two people fart silently at the same time. Both are comfortable with the smell only till they realize someone else farted.
| 18 |
ELI5: Why does water mostly stay still while you turn a glass? | If you have a glass of water with ice and you try to turn the glass around to drink from another side, the ice will mostly remain in the same spot while the glass turns. So if the ice was hurting your teeth and you wanted to drink from an end where the ice isn't, it's not as easy as I feel it should be. What is happening and why is it happening? | 15 | Physicist here.
So imagine that the water is made of several layers starting from the walls of the glass and going in.
When you turn the glass, the layer of water that is touching the walls of the glass will rotate with the glass itself, because it is being directly pushed. Then, the first layer of water tries to push the second one (which is closer to the center of the glass), but since water behaves like a liquid there is less friction between the two layers of water than between the first layer and the glass. This way, the second layer won't rotate as fast.
Add this up for all the next layers and soon the effect of the rotating glass will no longer be noticeable in the inner layers.
To solve your problem, simply keep spinning the glass so more momentum is transfered over time to the inner layers, eventually making the ice in the center spin.
Enjoy your drink! | 27 |
[Captain America civil war] If Thor was on Earth when the events of civil war happen do you think he would pick a side? or try to stop both teams from fighting | 43 | This is an interesting question, because it gets to the heart of Thor's character arc.
First, his entire initial showing revolved around Thor learning the dangers of running off half-cocked and ruining things for everyone else. Odin stripped Thor of his power and banished him from Asgard because he used his power and authority recklessly, threatening to bring war to Asgard.
That's the same lesson Tony learned in Sokovia, and the reason Tony supported the Accords. From that point of view, Thor could very well back Team Tony.
On the other hand, the only individual Thor has *ever* met, in five thousand years, that he considered worthy of wielding Mjolnir was Steve motherfuckin' Rogers. Roger is a *leader*, the guy who makes the hard calls and decides when it is, and isn't, worth fighting.
And that's the lesson Odin wanted Thor to learn. Odin didn't want to turn Thor into a sycophant or a follower: he wanted to make sure that Thor was ready to become a *King*, to make sure that when Thor *decided* it was time for war, it would be the *right* decision. Odin wasn't preparing Thor to wait on the sidelines for someone else to unleash him, he was preparing Thor to unleash his power *while being mindful of the cost*.
So from that point of view, Thor would be Team Steve. He would understand Tony's regret and desire to prevent innocent casualties, but he would *never* submit himself to a nameless, shadowy organization with unknown goals. Thor is a King, and *he* decides when it's time for war, and Thor would place the same confidence in Steve Rogers' judgment. | 97 |
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[Star Wars] Did the Emperor just choose an off-the-shelf protective burnsuit/ventilator for Vader or was that custom made? | Please select a color for your **burn mask w/cowl**:
* desert sand
* midnight black
* Corellian blue
* bantha fur brown
* protocol droid gold
* chrome | 30 | Everything about Vader's suit was custom made to make him as effective, terrifying, and intimidating as possible. It's also been upgraded several times over his tenure as a Sith Lord, making it even more powerful and thus making him even better at killing Jedi and other enemies of the Empire. Also side note, the design of the suit was meant to invoke ancient Sith warriors who wore similar armor in times long past. Darth Bane (or at least the visual representation of him that confronted Yoda) wore something very reminiscent of what Vader would wear a thousand years later. It was 100% custom designed and built on Palpatine's order.
In old Legends continuity, the suit was intentionally made to hinder Vader's movement and always keep him uncomfortable and angry. In current canon, Vader has enough self loathing and self-inflicted mental anguish that he does not need to feel physically uncomfortable to tap into the dark side. The suit in fact makes him far more physically powerful than he ever was, and it helps him feel like the monster he thinks he is. | 24 |
ELI5: why do the moving parts of cartoons have a slightly different color? Like if a car for is about to open, it will be a slightly different shade of color until it opens. Then when it's closed/done moving independently, its color matches the rest of the car. | 1,101 | Those are animation cels. Rather than have the animator draw the background for each frame, they instead have one background sheet, and then a series of celluloid sheets with the movements of foreground objects.
Because of the different techniques for creating celluloid sheets, colour matching between the background and foreground was not perfect. This is why you can tell when something is going to be a moving object based on its colours. | 891 |
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ELI5: Does understanding E=MC2 actually require any individual steps in logic that are more complex than the logic required to understand 2+2=4? | Is there even such a thing as 'complexity' of intelligence? Or is a logical step, just a logical step essentially, whatever form it takes?
Yes, I guess I am suggesting solving 2+2 could require logic of the same level as that required to solve far more difficult problems.
I'm only asking because I'm not convinced I've ever in my life applied logic that was fundamentally more complex than that required to solve 2+2. But maybe people with maths degrees etc (or arts degrees, ha, I don't have one of those either) have different ideas?!
If you claim there is logic fundamentally more complex than that required to solve, say, basic arithmetic, how is it more complex? In what way? Can we have some examples? And if we could get some examples that don't involve heavy maths that will no doubt fly over my head, even better!
I personally feel like logic is essentially about directing the mind towards a problem, which we're all capable of, and is actually fairly basic in its universal nature, it just gets cluttered by other seemingly complex things that are attached to an idea, (and that are not necessarily relevant to properly understanding it).
Of course, on the other hand, I glance at a university level maths problem scrawled across a blackboard, that makes NO sense to me, and I feel like I am 'sensing' complexity far beyond anything I've ever comprehended. But my intuition remains the same - logic is basically simple, and something we all participate in.
I'm sure logicians and mathematicians have pondered this before. What are the main theories/ideas? Thanks!
(I posted this as a showerthought, and got a couple of really cool responses, but thought I'd properly bring the question to this forum instead). | 86 | Not directly answering your question since E=mc^2 is physics, not maths. So requires observation in addition to pure logic.
Let's stay within the realm of mathematics.
Technically almost all mathematical results can be derived from a set of axioms (assumptions, logic is useless without assumptions)
What makes no sense to you is all the notation, each symbol, each operation, is specifically defined based upon previous more elemental operations and/or symbols. Mathematicians do this because it would take far too long to do everything from first principles.
So technically, you can break almost all of pure mathematics into "basic logic", but by that point there'd be so many steps it would be kinda pointless | 44 |
ELI5: Why are humans more interested in planetary travel/discovery rather than fully exploring all of Earth first? | 27 | There is interest in exploring all the unknowns. There are teams studying the ocean floor and atmosphere and finding what they can on earth.
But earth is still local and a limited space, and when considering the pace of humanity, space is where we will continue to expand. And like the many nomadic tribes before us, we always are looking out for the next possible place to settle. | 34 |
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What is the general Marxist view on charity in the modern sense, and more specifically, charity based organizations? | 20 | In general, if the means of production aren't changing hands then nothing is *really* changing and this is why charities aren't effective enough for the Marxist: they don't cause lasting change that empowers the beneficiaries, they don't allow for an escape from poverty. | 16 |
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Can you make blackholes from electromagnetism? If so, why are there so many made from gravity since electromagnetism is so much stronger? | 15 | Black holes are a gravitational phenomenon.
However, an object with electric charge (and black holes can have electric charge) creates an electromagnetic field around it. The energy and momentum in this field are included in the energy-stress tensor, the source of gravity in general relativity. So the spacetime *metric* (which describes how spacetime is curved) is a bit different for a charged body than for an uncharged body.
But again, although the electric charge of the body does ultimately affect spacetime, it's not really the charge *per se* that matters, but rather the energy and momentum in the electromagnetic field. And, of course, it's all just a source term included in equations that describe *gravity*, not electromagnetism. So there is really no such thing as "a black hole from electromagnetism". | 16 |
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CMV: Hillary Clinton is More Economically Conservative than Donald Trump | **NOTE: THE POINT HAS BEEN PARTIALLY CONCEDED. SEE EDIT #3**
Donald Trump's tax plan is estimate to raise the deficit by[ an unprecedented 10 trillion dollars](http://www.politico.com/story/2015/09/donald-trump-tax-plan-analysis-deficit-214211) over the next decade. While this deficit is coming largely from a decrease in taxes, there are no estimates I'm aware of that the resulting growth in GDP would come even close to make up for it.
In order to pay for this, Trump has only (as far as I know) suggested cutting two federal agencies: The EPA and the DoE. However, the EPA's annual budget is only about $8 billion and about $108 billion on the DoE. Cutting those two departments from the budget totally would only make up for 10% of the revenue loss Trump proposes.
Additionally, Trump has pledged to spend more on the Military, infrastructure, and a border wall with Mexico estimated to cost billions of dollars, which I don't believe for a second Mexico will pay for. At the end of the day, Trump's federal budget will be a net increase of expenditures with a net decrease of revenue.
Since it is the economically conservative position to *not* have the federal government run on ever-increasing deficits, the fact that Hillary Clinton's plan does not increase the deficit by this much makes her the more economically conservative candidate by default.
EDIT: Since the discussion is turning into a debate over what I mean by "conservative" and "liberal," here are my definitions copied from one of my responses:
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**Conservatism** is the support of traditional morals and values (in the American context, the support of the Protestant Christian moral and value system), limited federal government power, lower taxes, less government spending, fewer government programs, the preference for private enterprise over public works, and the promotion of the traditional 18th - 20th century American family structure (one man, one woman, and children).
**Liberalism** is the support for acceptance of a variety of moral and value systems, increased federal government oversight, a progressive tax tier with very high taxes for higher income brackets, comprehensive government public welfare programs, the preference for public works over private enterprise, and the inclusion of new and non-traditional family structures.
_____
EDIT #2: A number of posters are missing the nuance of my post. Please keep in mind that I am discussing how each candidate's plans stack up to the conservative ideal ***WHEN IT COMES TO ECONOMIC POLICY AND ONLY ECONOMIC POLICY!***
In order to change my view, you will have to provide evidence that Trump's economic policies will result in a lower deficit than Clinton's. This is not snark, and I do not believe this is an impossible task. I am definitely willing to consider changing my view if someone provides me with evidence counter to what I have presented.
I will no longer respond to comments that go outside of the economic policy scope. I thought my inclusion of the word "Economically" in the title would be sufficient to keep the discussion along those lines, but apparently I was incorrect.
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EDIT #3: Apparently I am guilty of misreading some of the posts here, and for that I apologize. I concede that Trump is more conservative than Clinton when it comes to economic policy as a whole. When I said economic policy what I meant was the deficit specifically. However, I did not specify this originally, so I have awarded Deltas to those who pointed this out.
I will award additional Deltas to anyone who can convince me Trump won't increase the deficit as much as Clinton will.
> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | 18 | I don't agree that the conservative position is "to not have the federal government run on ever-increasing deficits." The two modern presidents who had the federal government run *the most* exorbitant deficits were Ronald Reagan and George W. Bush. Do you have any evidence for your position? | 18 |
[Pokemon] Whenever trainers catch Pokemon like Magikarp, Relicanth, Whiscash, or other fish-like ones, how the hell do they survive on land? How do they move around? | 63 | [](/derpyhappy) They can survive being roasted, poisoned, paralyzed, electrocuted, hyper-beamed, exploded, constricted, stabbed, bitten, telepathically assaulted, crushed, or haunted. You're worried about them *suffocating?*
As for locomotion, well, they're pretty good at flopping around. | 54 |
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ELI5: If alternating current oscillates back and forth at equal frequencies, how does power still flow in only one direction? | 20 | Imagine you want to move a heavy box. If you push it, where does power go? Well, it goes from your hands to the box, and then into the friction of the floor.
What if you pull it instead? The power still goes *from you* to the box, and then consumed by friction! So, no matter if you push or pull, the power goes in the same direction!
In general, power transfer can go any direction, direction of actual movement doesn't matter: it can even go in direction where there is no movement at all (like a motor connected to a wheel. The power goes from motor to a wheel, but nothing moves in that direction!) | 41 |
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[40k] Has there ever been any case of chaos ever working with any of the other factions in the 40k universe? | I don't know why I ask, but I've seen Imperium/Tau/Eldar alliances, and it just crossed my mind, has chaos ever had an alliance with any of the other races, even if it was a sort shaky alliance that ended in betrayal? | 18 | Since the warp entities can't enter the material plane without being summoned and sustained by someone else then they have had 'alliances' with everyone. The chaos space marines are in a way allies of chaos through corruption or promises of power and almost every race has had some of its members corrupted at one point or another. | 11 |
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