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Do we call linear equations as linear because when we plot them we get a straight line? | 19 | Yes. But what's annoying about this is that there's another, much more useful definition of linear in many fields of math, and the straight line equation y = ax + b is NOT linear in that sense, unless b = 0.
Instead it's called "affine" when you use that definition of "linear".
Among other things, that kind of linea... | 26 | |
How is underwater fiber laid out over fault lines? | I was reading the article about Google pairing with a company to lay new fiber from the west coast to Japan. [source](http://thenextweb.com/google/2014/08/11/google-backing-new-300-million-high-speed-internet-trans-pacific-cable-system-us-japan/).
Is the fiber laying on the sea floor? Wouldn't earthquakes and underwat... | 429 | As far as I've seen, it's not secured to the sea floor at all. So the sea floor can move and the cable will be just fine. The big downside of that is ship anchors will catch on the cable and the ship can rip the cable apart. Happens all the time, so they usually lay more than one cable at once and they also keep it a... | 99 |
ELI5: Why are weather forecasts sometimes so different from each other? Don't they all use the same data and science? | I'm talking about information displayed on different weather websites. One will say that there's a very high chance of rain in a place at a certain hour, for multiple hours, and another will say that there will be just some light rain in the first hour, then it will be dry/sunny. | 32 | There are a couple of main models that almost all forecasting sites get their information from. The US model is GFS and the European model is ECMWF.
Some websites will just pass on Unmodified forecasts direct from one or other of these models.
Some websites will combine the data in some way and present a likely avera... | 32 |
ELI5: How does copper in gloves, socks, or compression sleeves relieve pain? | I keep seeing commercials with Brett Favre or other people talking about copper in socks or other sports related equipment and how it relieves pain or increases circulation. How does this work? Or, possibly a better question, why is it bogus? | 23 | It doesn’t do anything.
As for why it’s bogus; that would be because it doesn’t do anything.
Fools are easily parted from their money and there’s always someone willing to sell them some bullshit. | 72 |
[Marvel/Dc] Which Super Heroes are closest with one another ? | And not just as superheros,like outside of work,like personal lives and such... | 17 | * Luke Cage and Iron Fist. Buddies and business partners.
* Spider-Man has his Amazing Friends, Iceman and Human Torch.
* Daredevil and Black Widow used to date. They probably have more history than Black Widow and Hawkeye in the comics. This never comes up nowadays, but it used to be a big thing.
* Star-Lord and Nova ... | 30 |
ELI5: What happens to the electrons in a depleted battery? | 26 | After traveling through the circuit, they end up back in the battery (on the other end of the cell), but in a lower energy state (bound to a different atom or molecule). The electrons aren't "used up," but they do carry less energy when they return. | 18 | |
ELI5: If a spaceship had a flag, would it wave as the spaceship moved through space? | 414 | If the ship was accelerating, it would "hang" toward the back of the ship, as if it was hanging down from a horizontal pole on Earth, with no wind. When the ship stopped accelerating, it would spring forward a bit, from released tension, but would then float freely until it reached a point where no forces were acting ... | 450 | |
I feel that the film American History X fails to deliver the message it intends, CMV | If you haven't seen American History X, it is a 1998 American film staring Edward Norton. Norton plays Derek Vinyard, a leader of a Neo-Nazi skinhead gang in Southern California. Other key characters I will discuss are Derek's younger brother Danny. His mother Doris. His father, Dennis. Derek's neo-Nazi mentor Cam... | 28 | > Tony Kaye, the director, wanted the film to end with Danny being killed and a shot of Derek shaving his head again- indicating he hadn't changed. It would have been an ending vindicating Derek's neo-naxi beliefs and not a lot of room for the audience to point to anything in his life to again, show him where his be... | 40 |
ELI5: what makes our voices so different? | 31 | Our vocal cords are like the strings on an instrument. If the same note is played on a violin versus a guitar, the strings are vibrating at the same pitch or frequency. However, because of how the vibration radiates through the different shape and materials in the instrument, the note sounds different coming out of the... | 29 | |
You've just been declared supreme potentate of Venezuela. Now how do you fix the economy? | Implicit in your power as supreme potentate is that you can write any law you want, create any policy. You can appoint whomever you want in what ever position.
Of course you are benevolent so how do you turn Venezuela around minimizing the loss of life and and maximizing your citizens' standard of living. | 44 | Any economist will tell you that important in maintaining economic growth is:
Strong private property rights (having households be the primary economic decision makers is fundamental to the proper functioning of markets)
free trade (with products today requiring global value chains to manufacture, it's difficult to d... | 42 |
ELI5:How can a whitening toothpaste actually whiten our teeth if we rinse as soon as we're done brushing ? | To me it seems like all we're doing is cleaning out teeth, but there's no way they will actually whiten ... | 26 | First, those toothpastes are not really very good for your teeth. They use harsh and/or abrasive materials (baking soda or peroxide) to whiten which are, again, not super healthy.
But, that means that the action of brushing your teeth is what actually does the whitening bit. If you brush your teeth *correctly*, that ... | 12 |
Eli5 How does a Body's immune system eventually recognize a donor organ as a part of it instead of a foreign entity? | 21 | Oftentimes, it never does. The body's immune system will continuously recognise the transplanted tissue as foreign, due to the immune system not being able to identify the proteins on the cells as its own. People who have had organ transplants often have to take drugs to suppress the immune system for life, as otherwis... | 38 | |
If microwaves are non-ionizing, then why are they harmful to humans and radio waves aren't? | Is it because microwaves only in large doses are harmful, and radio waves are never in large doses? | 21 | Microwaves aren't harmful any more than radio waves. In fact, microwaves are more of just a subcategory of radio waves.
What you really are asking is why a microwave *oven* is harmful to a human if they could somehow get inside, but radio tower a kilometer away isn't. What it comes down to is intensity. The radiatio... | 38 |
ELI5: Why does seeing something agressive or evil in a rorsharch test indicate mental illness? | 19 | Rorsach tests reveal the way you see the world. Such people see aggressiveness & evil even in benign things where no evil intent or aggression actually exists.
People who see imagined aggression are often/always on the defensive, taking offense in the simplest situation or comment. Aggression is at least an actio... | 12 | |
[DC Comics] Can Aquaman control sea creatures that live on other planets? | 26 | When Aquaman was on the planet Vortuma, he was able to communicate telepathically with the indiginous intelligent aquatic life. it stands to reason he should also be able to do the same with aquatic animals from another planet in that case. | 23 | |
I just planted seeds. What are they doing now? | Specifically, in the first few hours in a good environment with water? | 44 | The answer to this is "not a great deal in the first couple of hours" though it very, very much depends on what seeds they were.
The principal triggers for germination are sufficient water availability, oxygen and the correct termparture range. With those 3 things right seeds will germinate.
Light can be a germinatio... | 13 |
ELI5:Why do paparazzi not get the same flak as the person whom hacked the nude pictures in the fappening? | Paparazzi who take candid photos of a celeb with a long lens while they are topless, etc seem to have no repercussions.
A hacker who steals the photos gets hunted down.
I'm not saying either of them are right. I just want to know how one seems to be ok and the other isn't.
Edit: fixed up grammar mistakes (whom/who). ... | 2,484 | Because when you are in a public space, you have no reasonable expectation of privacy. Everyone can take your photos and the photos would belong to them.
A hacker on the other hand steals something belongs to you. What's in the photos doesn't matter legaly. It's yours and taken without your consent.
Edit: Some peop... | 1,177 |
ELI5: Why have movie ticket prices and more so popcorn prices vastly outstripped inflation. | 19 | The biggest reason is that where theaters make majority of their money. The big box office numbers are not going to the theaters but the people who make the movies. Most movies make majority of their money in the first two weeks after release and take into between 40 - 55% of a ticket sale. | 15 | |
[Buffyverse] If Gunn can be a poor kid in L.A. who does vamp and demon hunting with his own assembled gang, what makes the Council and the Slayer so special? Sure they have the funds and she has the super strength but hell Gunn trained himself and he regularly fought vamps/demons sans superpowers. | 37 | Gunn has a gang on his side and doesn't aim his sights higher than any two-bit sucker who wanders into his neighborhood. The Watchers tend to operate on a higher level with higher stakes (haha), while the Slayer traditionally works alone to avoid collateral damage (and this is said to be the reason so many of them die ... | 39 | |
What is the point of correlation studies if correlation does not equal causation? | It seems that every time there is a study posted on reddit with something to the effect of “new study has found that children who are read to by their parents once daily show fewer signs of ADHD.” And then the top comment is always something to the effect of “well its probably more likely that parents are more willing ... | 4,519 | Correlation does not equal causation, but there still may be a causal link, even if it is not a direct one. Understanding this link may give us insight in related concepts, and often the first step in understanding this link is to identify a pattern.
So you're right, TV sales correlating with deaths alone is mostly m... | 4,009 |
[Star Trek] You get your own personal holodeck and go live there. All your food is holodeck food. Does it provide the nutrition you require? What happens if you eat nothing but holofood and then leave the holodeck? | For question one: We need to determine how real things are in the holodeck. I can think of sources both ways that things are completely real, and not real that real.
For question two: Say the eating holofood is for a year. Enough time to have a significant portion of your body created from / sustained by holofood. | 21 | The Holodeck also uses replicator and transporter technology. Some items that people interact with, that would need a high fidelity, are replicated and transported into place. The program/computer determine this as needed. The same goes for food. It is replicated and transported into the simulation. The food you ea... | 47 |
ELI5: Exactly how useful is a constantly scrolling stock ticker, like one would see on the side of a building or on the bottom of a TV news network, to a modern investor? | Thanks to the internet and modern electronic trading platforms, any stock price is available instantly with a simple search. Is the scrolling ticker feed showing price updates that runs at the bottom of CNBC or on the side of some buildings in NYC still a useful tool in 2018? | 64 | its mostly anachronistic at this point. even calling it a ticker is from when it came across the wire and was typed out with a telegraph. ticker tape parades were just bunches of this paper being thrown out the windows onto parade goers. i think people mostly use them now as an historical nod to the market rather th... | 41 |
What is the role of men in feminism, white people in anti-racism and cishets in pro-LGBTQ movements? More generally, what is the place of someone who finds themselves outside a movement and privileged by what it fights? | Where is the line between being an ally and taking over as the voice of a movement when you yourself are someone whose voice is normally heard? It makes no sense for it to say "men should take center stage in feminism because their voices are heard" since this merely reinforces the inequality which is sought to be diss... | 31 | Check out Alice Jardine and Paul Smith's anthology Men in Feminism; Frank Wilderson III also talks about this issue in Afropessimism (surprisingly, he is not very optimistic about white anti-racism)
On a more practical note, these movements are very broad, and each group or even individual will have a different opini... | 13 |
CMV: Batman demonstrates quasi-superhuman abilities, despite his supposed status as a "peak human" with no powers. | I should note that this post isn't meant as a criticism of the Batman mythos; although the character isn't my absolute favorite, I prefer Batman to pretty much any other DC comics hero. In most of the cannon Batman works (i.e. excluding the Frank Miller portrayal of the character in the *The Dark Knight Returns*, *The ... | 411 | The baseline human in DC comics is generally more durable, quicker, and stronger than real humans. Batman punches people through walls and yes, that's unrealistic, but those people are often non-powered themselves and they survive being punched through a wall with no permanent injuries, which is also unrealistic. Unaug... | 464 |
Is the phrase, a star that shines twice as bright but half as long a true statement? | What controls the brightness of a star? | 78 | It turns out to be *almost* true!
For stars in the main sequence, the bigger you are, the brighter you are. The brightness all comes from nuclear reactions, and how the reaction rate for nuclear fusion goes up really strongly as you increase the temperature and pressure. A more massive star has a much hotter and high-... | 80 |
Do we know what early homo sapiens and neanderthals did with people who broke bones? What would happen if a person broke their leg? Would they die? Would someone kill them? Would they be abandoned? | 47 | I watched a documentary once on an excavation of a Neanderthal cave, and one of the skeletons was of an older individual with a crippled arm. It wasn't totally useless, he'd still have been able to carry things. But he wouldn't have been much of a hunter.
It was an old injury, probably one he'd had for decades, but he... | 46 | |
With nothing but hydrogen and oxygen, how come water isn't flammable? | It sounds like the ingredients of a bomb! | 19 | For the same reason CO2 isn't, and the same reason an anvil on the ground can't fall on your head. Water is what you get when hydrogen is burnt. It's already ashes. You can't burn ashes.
Scientifically: Water is at a very low energy state. For a chemical reaction to release energy, it has to move from a high energ... | 60 |
Why does heat cause visible waves through the air? | 146 | Warm air is less dense than cold air. And different temperature masses of air have different indices (the plural of index) of refraction--they bend light by different amounts. So the air above a hot object is less dense, is rising because it is more buoyant, and bends light differently. Naturally, light that must pas... | 58 | |
ELI5:Many sharks and other large fish have been kept in captivity for long periods of time but why has this not succeeded with Great White Sharks? | *thanks for all the responses! I believe I can wrap my brain around it better now. | 7,738 | Coming from an aquarist who works with sharks- Great White Sharks are what are called ram ventilators. This means they constantly have to keep swimming to keep water passing over their gills. Sharks have what is called a glide pattern- they have a burst of swimming, then having a gliding portion. When kept in human car... | 8,409 |
ELI5: Why don't soda crackers absorb mineral oil and why should I care? | My mom hosted a skin care and make up party last weekend. I came by after the party and saw a couple of Saltines (soda crackers) floating in liquid. I asked her about them and she said it was demonstration that the product rep had done.
Apparently, if you put a Saltine in a bowl of water it become soggy very quickly. ... | 43 | first of all, that demonstration sounds like its designed to deceive people into somehow thinking that what a cracker absorbs or does not absorb has any bearing on how healthy it is for human skin. Second, oils are non-polar molecules, water is a polar molecule, and food is organic (life loves water) The cracker absorb... | 36 |
The disproportionate success of Asians proves that racism is not what is keeping Hispanics and African-Americans back. CMV. | I work in finance and meet some very successful and well-paid people in many fields. They are mostly white and Asian. The success of Asians in America, whether Asian-American or Asian immigrant, is a statistical fact. This suggests that the reason for persistent poverty in other minority cultures is not a result of wh... | 53 | The stereotypes of asians and those of blacks and hispanics are very different in the US.
Black people are stereotyped as lazy, athletic and stupid. As rappers, sports stars and gangsters.
Hispanics are stereotyped as unreliable, dishonest and cheap. As fast-food workers and illegal immigrants.
Asians are stereotype... | 37 |
[General] If someone with lycanthropy was in a coma, would they still turn into a werewolf at full moon? | 62 | It's typically an involuntary reaction, so yes.
An exception might include those situations when the person transforms only when they happen to notice that the moon has come out from behind some clouds. Those situations seem to require not only direct moonlight but also, possibly, the person actually seeing the moon. | 46 | |
ELI5: Why does the wind whistle and howl when it's cold, but not when it's warm? | 498 | Two part answer:
1. The wind does whistle and howl when it's warm also. Go to a sailing club on a windy enough day, warm or cold, and you'll hear the whistling and howling in the masts and wire rigging.
2. Cold air is more dense (heavy), so you get the whistling effect at a lower speed. You might not hear the whi... | 164 | |
[Superman] Can Superman get cavities while on Earth? | 26 | Probably not. 1) if bullets don't hurt him, sugar and bacteria probably won't. 2) bacteria that cause tooth decay might not recognize Kryptonian anatomy. 3) Superman eats an extremely healthy diet (I'd imagine). | 26 | |
CMV: I think the Palestine government should accept defeat. | They are fighting a bigger enemy and they will lose. Their civilians are dropping left and right. They should allow Israel to demilitarize them and start focusing on building infrastructure and educating their children. They should build a proper government with elections and laws. Get loans from the world bank and sta... | 29 | The Palestinian government *did* accept defeat. They realized that continued military conflict against Israel wasn't accomplishing anything, so they stopped supporting it. But the Palestinian people were still angry. So they voted in droves for Hamas, which then took over the Gaza Strip and continued to fight.
If Hama... | 25 |
[SuperPowers] How do people with Matter Manipulation are not considered op and don't just win every fight ? | 79 | Take Wanda Maximoff as an example. She's incredibly powerful and in a straight 1v1 she's pretty much unbeatable. She would have killed Thanos in Endgame with no effort if he hadn't ordered his ship to open fire, and in Civil War, when she was holding up that falling building, Rhodey broke her concentration with a sonic... | 97 | |
CMV: A life with religion is more meaningful and fulfilling than one without. | I'm an atheist. Lately, I've been thinking about what it means to be human, and live life. I've come to the conclusion that a life without the idea of a higher power, and a greater meaning, is ultimately emptier, and less fulfilling in a sense.
Without the idea of a god, or some sort of higher power, we are just coin... | 18 | Have you considered what it would be like if you were God? With no yet higher creator above Him, one would presume that His life is empty and unfulfilling.
So God must somehow give Himself meaning, and the usual story is that He did this by creating the universe. If creativity is sufficient to have meaning and fulfill... | 27 |
[ELI5] When and how did the days of the week sync up globally? | I think people have had weeks with assigned days for thousands of years, but with travel taking as long as it does I'm sure there have been many times in history where different cultures were 'on different days' at the same time.
I wonder when did it come to be that Monday is the same day in China as it is in Chad? Wa... | 15 | What you're talking about is basically the slow standardization of the planet on the Gregorian calendar. That was an upgrade of the Julian calendar, which was a Roman thing.
There's lots of obvious value in everyone being synchronized, particularly as long-distance travel became easier. There's nothing magic about th... | 22 |
ELI5: Why dont orcas (killer whales) see humans as food and attack swimmers/paddleboarders/ kayaks etc? Humans are the same size as most of their prey but them seem to mostly ignore us? | 132 | From what i understand about killer whales is that individual pods tend to have specific diets and hunting tactics passed down through the generations. Since humans are not consistently in killer whales hunting areas they wouldnt have developed a "taste" for humans or the tactics to hunt them. Thats obviously not to sa... | 90 | |
ELI5: How come minors have to pay taxes in the US? Since they can't vote, shouldn't they be tax exempt regardless of their income? | 3,361 | If minors were exempted from paying taxes, this would create a huge loophole in the tax code. Parents would put all of their securities in their children's names, so that they never had to pay taxes on the interest and dividends. Note that to a small extent, people actually do do this, but the tax code addresses it and... | 2,950 | |
ELI5: How do the federal banks of a country determine whether to increase or decrease interest rates? Like whats the relationship between interest rates and a country's economy? | 27 | Low interest rates make loans easier and stimulate investment.
High interest rates make loans more difficult and discourage investment.
Central banks use interest rates as a tool to try to increase economic growth or decrease it. Usually what they do is they watch the economy and they lower interest rates when unemp... | 23 | |
Which thinker speaks about the fact that humans have to decipher themselves instead of merely know themselves? | Psychoanalysis has taught us that we have deeper levels of character that unconsciously motivate us to act. We have repressed traumas that shape the way we behave. We have instincts that spark without the knowledge, will or consent of the self. We need to go on self-exploration in order to understand the way that our ... | 104 | I think Nietzsche was one of, if not the first to recognize this in opposition to the Catesian view. He says it explicitly in the "Genealogy of Morals" in which he says "we are unknown to ourselves, we knowers" as the first line of the book. | 30 |
[Harry Potter (Books)] Why does Harry et al believe that the Elder Wand's power will be broken? | A good chunk of *Deathly Hallows* is spent establishing the fact that the Elder Wand's loyalty doesn't require the death of the previous owner, but rather only that the previous owner is beaten (presumably through magical means, though there's indications that non-magical means works too). We see this in action when th... | 57 | The Elder Wand is to wizards what Excalibur is to muggles. If you're hearing secondhand that You Know Who had the special super wand, you're probably not going to believe it.
Add to that the fact that the wand isn't in Harry's possession. It'll get really confusing really fast who the true master of it is.
Harry goe... | 34 |
[Mario] Why would Bowser leave an axe right there in the bridge where he is standing? And why isn't Princess Peach in a cage? | 23 | The fire marshal required a fire ax in case of needed to chop through a door in the event of a fire breaking out. (Very likely considering the amount of lava and fire breathing Koopas in the castle.) Mario just takes advantage of Bowser’s rigid adherence to firecodes and OSHA safety | 33 | |
ELI5: Why can't fingers disformed from rheumatoid arthritis be "popped" back into place like a dislocated finger? | Here's a picture of an arthritic finger: http://www.glucosamine-arthritis.org/wp-content/uploads/2015/05/RAHands.jpg
Here's a picture of a dislocated finger: http://www.gunsnet.net/photopost/data/500/finger.jpg
To me, a person with no medical experience, I am not quite understanding why you aren't able to just "crack... | 312 | Arthritis is due to joint inflammation, which destroys the cartilage in between your bones and it ends up becoming replaced with fibrous scar tissue. When your finger is dislocated, the cartilage is still there, so you can pop it back into place. Connective tissue is very inelastic, and so it ends up causing joint defo... | 161 |
When you break a bone, which part hurts? | Is it the actual bone that hurts? Or is the bone poking into nerves? Or something else? | 49 | The periosteum (very thin layer that sits on top of the bone) is rich in nerve fibers that sense pain. When you fracture a bone, it's these fibers that get activated and give you the sensation of pain. | 27 |
[Dragonball Z] What is the difference between any beam-type energy attack? | Besides aesthetics, what is the difference between attacks like Kamehameha, Galick Gun, Final Flash, Masenko, generic 1-handed beam attack, or really any other beam attack ever. From the looks of it, the power of these attacks depend entirely on the user's power, and aside from that there is no other noticeable differe... | 27 | Ki attacks often represent the talents and goals of their creators, as they found a way to bend the energy so that it suited their talents best.
Your basic ki attack is nothing more than concentrating enough to turn your energy into an actual physical effect that can be thrown or channeled (a small beam). Any channel... | 22 |
[Jurassic Park] If Velociraptors were as smart as Jurassic Park portrays them, how effectively would they adapt if 100 were loose in modern day NYC? | Wow this really took off , I never expected much interest but now it appears we have the plot for Jurassic Park 5: the extinction of New York city.
Also, who wouldn't want to read u/cyvaris short story? we'll be waiting for it!
Edit: Scratch that.
it's now Jurassic Park 5: The Velociraptor of Wall street
UPDAT... | 186 | Well many of them would be captured or killed while they learned to hide and avoid man, but I'd imagine they'd wind up living in the sewers. They'd quickly learn to navigate them masterfully and any animal control folk (or any human for that matter) entering these catacombs could be quickly turned into lunch. If they w... | 157 |
CMV: A difference of opinion between two people when there is a significant knowledge gap on the subject shouldn't be called a disagreement. | To me, the term doesn't seem apt. On two fronts. In one sense it presumes that the opposing viewpoints are inherently equal. In another sense, it undermines the speciality of intimate knowledge with a subject.
For Example.
I have many friends who follow and study Novels. I wouldn't presume to denigrate their views o... | 703 | This is ultimately just a very fancy way of expressing the Fallacy of Appeal to Authority.
The fact that one person knows more about something is actually completely irrelevant to their argument. If a 1st year math student finds an actual contradiction in a proof their professor presents, the professor's greater knowl... | 235 |
If printing money is bad shouldn't leaving it deep in a multibillionaire's bank account where it will never be used be just as good as unprinting it? | Could making the rich richer reduce inflation? | 41 | Kinda sorta if you squint a lot.
In reality, your money is still an asset to the bank they can use. The money is never really "out of the system" entirely unless you take actual bank notes and stash them away.
Also, it's just kind of nonsensical policy. You hand people money on the pinky promise they won't use it whi... | 46 |
CMV: If your child injures my child due to reckless behavior that went uncorrected because you, the parent or guardian, were sitting far away and not paying attention, you are responsible for any damage done, especially any serious injuries. | I've got a 2 year old daughter and we've been to all sorts of parks. I also have a 6 month old, so sometimes I can't be directly next to her on the equipment, but I'm always near. I've seen many many unattended children and the bigger the child the easier to accidentally or purposefully move smaller children. We haven'... | 32 | This can just be extended back at you. If you were near your child, you should be able to stop anything before it blows up or at least mitigate any damage.
If you couldn't stop it, than there is no reason to believe if the instigator's parent would have either.
If you are always able to stop it, then clearly injury w... | 15 |
ELI5: How ancient sailors could navigate to a specific port? | How sailor going from Venice to Athens in the ancient time knew to navigate EXCTALY to the port location?
I can understand general direction by stars or even a compass but to navigate to a very specific location is other problem as I see it.
I did some foot navigation and to get to a specific point of very different ... | 167 | Venice to Athens is pretty easy since they would've had the shore in view all the time. They had maps and many landmarks to figure out their position.
For ocean travels, you only need to be accurate enough to hit the correct continent and then continue along the shore to your destination. | 239 |
Why is the speed of gravity limited to the speed of light? | I've been taught 4 things:
1. The speed of light is the maximum speed that anything can travel through space
2. Unlike light, gravity is not a force carried by particles traveling *through* space, it's caused by the distortion of spacetime itself
3. The expansion of the universe can happen faster than the speed of lig... | 40 | > Unlike light, gravity is not a force carried by particles traveling through space, it's caused by the distortion of spacetime itself
These things don't exclude each other.
> The expansion of the universe can happen faster than the speed of light
It doesn't make sense to call it a speed. The expansion is "spe... | 30 |
ELI5: Why do some substances melt instantly from solid to liquid (like water/ice) and other substances gradually transition (like magma, or metals)? | How come there is no transition state in between something like ice and water like how there is between stone and lava. Is there actually some sort of viscous, in-between, water/ice that I just don’t know about? | 47 | Magma is a mix of minerals with different melting points so when rock is heated, the minerals with the lowest melting points melt first and separate from those with higher melting points. This is what happens in the Upper Mantle when the basalt magma that creates the ocean floor separates from the higher temperature mi... | 25 |
ELI5: how do they know there are no matching finger prints? | 476 | They arent completely unique, mathematically speaking. Testing for prints is based on probability.
The odds of someone having the same fingerprints as you that lives in the same area as you is incredibly, *incredibly* small.
Fingerprint matching is used to reduce the likelihood of the prints belonging to someone oth... | 270 | |
After a few generations of living on Mars, would humans look different? | 61 | I don't think there's any way to answer these questions without being purely speculative, but any changes to the population would just be due to the different environment's effects on their bodies, and it wouldn't matter how many generations. Environmental conditions do not directly cause a species to evolve, and unle... | 25 | |
[Animorphs] How do you develop computers BEFORE you develop books? | This is one thing that I don't understand about Andalites. How on earth can they have made a computer before they invented simple books? How can they view a book as less advanced than a computer? | 50 | It comes up reasonably often in the books that Ax is actually kind of stupid in comparison to most Andalites. The things he says, particularly about history, should be taken with a grain of salt. That said, here is a plausible explanation: Trees, while not exactly sacred, are treated with a great deal more respect on... | 74 |
[harry potter] why did snape never tell dumbledore where voldemort was hiding? | when snape became a spy, why did he never tell dumbledore where voldemort's hideout was? I guarantee that if he had told, Harry would not have been an orphan. | 32 | Just because you know where a hideout is, doesn't mean you can take it out.
Voldemort's base was likely guarded with all sorts of horrific protection spells and enchantments which would seriously wound/kill/torture any who tried to enter it. And this is assuming that Voldemort didn't also use the fidelius charm or some... | 51 |
ELI5: Why are fundamental Christians, who are otherwise so opposed to other religions/beliefs, generally so pro-Israel? | They do know that Jews aren't Christian, right? | 23 | One of the prophecies mentioned in the bible is the coming of the messiah. The basic concept of a messiah is someone who will come along and make the world perfect, ending things like war, poverty, hunger, etc. Christians believe that this messiah will occur as the return of Jesus, although Jews do not believe that J... | 28 |
[Star Wars] Why is a pod worth less than Anakin? | How is a pod that can go like a billion miles an hour be worth less than a slave on a planet full of slaves? Got this idea from prequel memes btw | 106 | Anakin has his entire life ahead of him.(He's supposed to be 9 in Phantom Menace) He's a gifted mechanic, and he's worked in Watto's shop his entire life. The Pod *might* be worth more on an auction block, but Anakin is worth a lot to Watto. | 158 |
ELI5: Why do the air from air conditioners smell different when you turn it to fan mode? | 38 | Humidity.
Ever wonder why farts stink so bad in the shower? Humidity.
Air conditioners take humidity out of the air, so you can't smell the scents in the air as well. When you switch to fan mode, no humidity is lost, so you can smell all of those scents. | 19 | |
Why can insects survive so long after receiving wounds that would instantly kill a human or other animal? | 26 | You're talking about cases when an insect loses its head and such, aren't you?
Their nervous system isn't like ours, to begin with.
The human nervous system consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS contains the brain and spinal cord. The PNS consi... | 27 | |
I think that porn should be regulated a lot more because it is destructive to families and relationships. CMV | I think a lot more people are addicted to porn than will care to admit. I think this because I see a lot of threads around the internet where people are trying to stop using porn for the longest time possible, and most do not last more than a couple weeks. I think that porn has a negative effect on your sexual life, si... | 17 | There are a lot of things that can wreck a relationship, but ultimately it's not the government's job to be your relationship counsellor. Pornography is a form of speech, and free speech is protected by the first amendment. You'd need to show a much greater harm than "it teaches you unrealistic expectations for sex wit... | 22 |
[DC] Bruce Wayne is an identical twin, both surviving witnessing the death of their parents. How does growing up with an identical sibling who shared the same experience and trauma impact the timeline? | 488 | The way the DC universe operates?
Bruce still has all the baggage and trauma from that night, and in any ordinary circumstance having a sibling at all might help them work through the trauma together. But his twin, Bryce? He reacts entirely differently. Bryce wants to help, but Bruce is entirely withdrawn, respondi... | 430 | |
[Doctor Who] What is it with the Doctor's obsession with humanity? | Why does the Doctor's adventures/travels revolve around humans and Earth so much? What makes humankind so special? | 55 | The Doctor waxes poetic about humanity quite a bit, so he definitely personally considers them at least one of the most interesting species and actively wants to be around them. Two things also stand out about them:
1. Humans have more capacity for compassion, creativity, bravery, etc. than almost any other alien race... | 62 |
Is there a limit to how small a nuclear explosion can be? | After doing some research, I found out that the "Tzar" bomb is the most powerful thermonuclear weapon with a yield of 50 megatons of TNT. Anything within 20-30 km from the epicenter of where the bomb is dropped will be destroyed. Would it be possible to make a nuclear weapon that would only explode to become the size o... | 23 | Hi, nuclear engineer here. In answer to your question, no there is no limit to how small a nuclear weapon can be.
It is true that you need a critical mass to START a reaction, but nothing dictates how long that reaction must go on. Remove the tampers that hold the thing together so it blows apart faster (and cuts of... | 20 |
Eli5: There are several non filtered tobacco smoking options such as cigars, pipies, etc. Why do cigarettes have filters when they don't actually "filter" anything? | 30 | Filters do filter out a part of the smoke compounds. A lot of bad compounds pass through though. So smoking with a filter is still bad. The main reason for the filter is that smoking with a filter feels milder on the throat. Moreover, it is less messy, as they prevent pieces of tobacco from entering the mouth. Yuck. | 57 | |
If God exists; why does he allow horrible things to happen to good people? | I’ve recently become interested in theodicy and I can’t find one argument for God that makes sense. I believe in life after death but I don’t know if I believe in God. I’m looking at horrible things happening in Ukraine and don’t understand why he allows these things to happen if he exists. Does anybody know of a more ... | 21 | Part of why the range of arguments in this field can, at times, feel so narrow is because the philosophy of religion still almost exclusively looks at a very particular conception of a particular god (the Abrahamic one). This is a single monotheistic god possessing omnipotence, omniscience, benevolence and other charac... | 16 |
[DC] So, Superman is apparently super duper smart. Is that because of the sun, or are Kryptonians just naturally smart? | So, I've heard that Superman has superhuman intelligence as well as super strength and speed. I've heard someone call that dumb that he'd have super intelligence because he lives by a yellow sun, but since he's an alien, I'd just assume that he's smart because he's a Kryptonian. Like, Kryptonians just have a powerful m... | 27 | A little bit of both. He has sun crystals in his Fortress that can act as artificial intelligence tutors. His dad was a world-renowned scientist, so the intelligence could be genetic. The yellow sun boosts his perception and his mental capacity, allowing him to read, react, and think faster. | 36 |
ELI5: If the Boiling point of Water is 100 degrees Why does a Kettle boil at 60 degrees? | **I did Google This don't worry, I just could not find an Answer**
I cant for the Life of me work this out. and my Facebook friends are all like;
"How do you know it's boiling at 60c"
Well Our Kettle has Settings from 60-100 Degrees Celsius (Australian)
The water is all bubbling like It's boiling at 60c then Shuts of... | 18 | Are you talking about an electric kettle? Water boils at 100°C at standard pressure, *no exceptions*! However, the water temperature in the kettle is not even. Around the heating elements, the water rapidly reaches 100°C, even if the water in the rest of the kettle is cooler. | 27 |
[Marvel] Would a thread of Adamantium have the exact same effectiveness at holding up, say, a one tonne block as an Adamantium cable does? | I only ask this because Adamantium is pretty much indestructible barring reality warping and other higher powers.
Edit: I think I wasn't clear enough: The block is being hung from a crane by the thread/cable. | 32 | Follow up questions:
Can adamantium break? If not, how can a thread be weaker than a pillar?
Can adamantium bend, but still return to its original state (like a spring)
Can adamantium deform (be dented like play dough)?
How thin can adamantium be?
| 23 |
CMV: Most political podcasts are heavily biased and no more reliable than any other form of media | Many people on all sides of the political spectrum are realizing that the mainstream media is not a reliable news source. However, I see people following various podcasts instead (TYT, youtube podcasters, candace owens etc).
These podcasts are just as biased (if not more) than any other form of media, encourage tribal... | 32 | The fact that the media are biased means you should consume more, not less. Yes, most political podcasts have a viewpoint; it's hard to imagine one that didn't. People who inform themselves enough to run a podcast must be highly motivated, and it's hard to be motivated about politics if you don't care about politics.
... | 27 |
[Alien Universe] How many species has humanity found in the universe? | Was the discovery of the xenomorph/space jockey our first contact? How many species are there in the Galaxy? | 19 | Arcturians are apparently a humanoid and sentient species, and apparently they were our first contact according to some extended universe stuff. The marines refer to a "bug hunt" as well, so presumably we've encountered several non-sentient aliens as well.
No telling how many other races though. Just that Space Joc... | 28 |
ELI5: How does my body know if I'm 'being watched' | 370 | It doesn't.
There have been lots of studies on this, and - in all of them - the results show that people actually *don't* know they're being watched at all. They only get it right about 50% of the time: exactly what random chance predicts.
The "feeling" you get, though, can partially be explained in an evolutionary s... | 801 | |
[Star Wars] Why did Luke use a green lightsaber rather than a blue one? | From what I understand, a blue lightsaber means that you view the force as a tool to accomplish tasks—that you prefer to use the force on a physical level. A green lightsaber, however, means that you view the force itself as an end goal—that you use it on the spiritual level, and wish to study it purely for the sake of... | 89 | Luke didn't know any of that stuff, he was just building a new lightsaber. The meanings to colors were lost with the Old Republic. Whatever crystal he found to use was apparently green. He didn't have any higher meaning to it.
He might have chosen green because of traumatic reactions to blue. He did have quite a ... | 121 |
Moving to another language (from Python/Javascript) | Hi guys,
I am fullstack Engineer (self-taught). I have been working for more than 14 years in the industry but almost always using Python or Javascript.
I would like to get a job in another language Golang, Java, Clojure or Rust. Lately with Python is really easy to find new jobs but I am kind of tired of doing the... | 31 | I’m baffled by the responses that suggest that kind of transition is unlikely. Languages aren’t difficult - problem solving is. And after 14 years you’ve done a lot of that. More difficult is moving domains - from a front end engineer to a distributed systems engineer for example. But even that’s not unheard of.
You ... | 12 |
[WH 40K] What are some of the best theories behind the two missing Primarchs? | Bonus, and the other(s) not accounted for? | 46 | Some Imperial scholars theorise that one of the Primarchs fell like a twin-tailed comet unto a world hosting a relatively undeveloped barbarian society alongside a sizeable native Ork infestation, a not-insignificant Eldar presence, Chaos taint, some elements of abhuman ratmen and "beast" men, and some kind of bio-orga... | 85 |
CMV: Repeat customers should be the ones getting discounts, not first time customers. | I know it varies in different industries. However, I see it more often where first time customers are getting discounts rather than the loyals. I say, if you have spent a decent amount of money somewhere you should be the one getting a discount, rather than the person who may just be deal shopping and you're risking ... | 286 | Those first time customer discounts are often loss leaders. They are a net loss in hopes that the customer will go on to become a profitable one. It is about increasing business, not "rewarding people." Not only that, but there *are* plenty of companies with loyalty programs. | 147 |
[Star Wars] Could someone with a very low midi-chlorian count become a powerful Jedi Master through training? | Yoda teaches Luke about the force, and it feel like a lot of it has to do with believing and understanding how the force works and less to do with how many midi-chlorians can be found in his blood...
Let’s say I have my blood tested and I barely register being force sensitive, but at the same time; from the beginning... | 52 | Most of us believe that the midi-chlorian count is correlation not causation. That the stronger you are in the force, the more midi-chlorians are drawn to you. So while some people are better than others at using the force, and traditionally the Jedi have focused on those people with in-born skills rather than trying t... | 67 |
ELI5: How is the lethality of a substance determined in an ethical way? | I recently saw a documentary and learned that the most venomous snake on earth (the Inland Taipan) can kill over 100 grown humans with its venom.
How is that figure determined? I know that it is not likely that some scientist tried to try and kill as many people as possible. So how is it done? How do we tell if someth... | 1,039 | > How is that figure determined?
Apply carefully measured doses to a series of rats until half of your sample dies. Consult prior research where lethality in rats was compared to more analogous animals such as pigs. From this you determine the LD50, the lethal dose for half of a given population. Then it is just a ... | 903 |
CMV: Stablecoins are not a new innovation. They are just banks. Unregulated and unsecured banks. | If I have 10 dollars in a bank account, I do not in fact own 10 dollars. I own 10 IOUs from my bank. I can redeem these IOUs for cash at my local bank, or I can use them for payment directly in a bank transfer and let someone else redeem them.
If the bank goes under, I can rest assured that my deposits are insured by ... | 578 | I think that by current internet business definition this is innovation. A lot of current internet innovative and "disruptive" business models are essentially ways to do old things while avoiding regulation.
Uber is essentially just taxi-cabs without the regulation. Taxi firms have apps, where they struggle to compete... | 179 |
ELI5: What's the situation in Libya today after Gaddafi lost his power? | 43 | There are 2 self-proclaimed governments, one in Tripoli (historical capital of Libya, west) and the other in Benghazi (center of the uprising, east). Plus more or less autonomous militias. Plus djihadists. Plus ISIS in Sirte.
It's a complete civil war. But actually Libya can still exports its oil at low price (because... | 17 | |
ELI5: How do bouncy balls bounce so high? | 15 | Let us imagine the perfect bouncy ball. A feature of it will be that if you drop it at any height, it will bounce up to about the height your dropped it. It will not bounce any higher than the initial drop unless you put in extra energy somewhere as energy cannot be created or destroyed, it can only be transformed into... | 11 | |
ELI5: How does Google Earth 3D view work? | Since Google Maps is photographed with satellites, I'd expect the image to be completely flat. So how do some areas have these precisely modeled buildings and trees? And how are the buildings textured from every side? I thought that satellites could only capture photos from a bird's eye view and not like this: http://i... | 97 | Google maps is now done by airplanes flying a grid pattern over the area. They have 6 camara pointing at different angles to capture sides of buildings.
Source: I've done work on a contracted Cessna 182 doing aerial photography for Google
Edit: this is only done in urban areas like in the photo you linked. | 38 |
ELI5: Medicare in the United States | I quickly read the Wikipedia of medicare and it said that it is for senior citizens in the Wikipedia but what I've heard sometimes is that it is the United State's version of universal Health Care. I guess I'm just confused, could somebody clarify for me?
Thanks | 50 | Medicare = government-provided medical aid for seniors
Medicaid = government-provided medical aid for the poor
The former is for all people that are 65 or over, the latter is only for those that qualify. Some have considered expanding medicaid to the point where it eventually becomes universal health care, but it's n... | 24 |
Eli5. How its possible for the light to travel constantly with out stop slowing down from the most old galaxies? | 78 | Light is special because it has no mass and always travels at, well, the speed of light. This is one of its fundamental properties due to the laws of physics. You can’t really compare light to say, a spaceship, because it’s just not the same thing.
But almost anything can move long distances in space without slowing ... | 67 | |
ELI5 Why do batteries work again after heating them up? | Sometimes if a remote or some other small electronic stops working because the battery is dead, I take the battery out and heat it up by putting it in my arm pit. The warmth heats up the battery and give it a little more juice allowing me to use it again for a minute. I also remember doing this with old mobile phones i... | 37 | You’re not necessarily recharging the batteries. But heat makes batteries more efficient/effective. Batteries have a chemical solution inside them that stores electrons. When the temperature of the battery is low, the chemical processes inside the battery is slower meaning the movement of those electrons is also slower... | 48 |
CMV: I believe that the captain South Korean ferry that sunk did nothing morally wrong. | I do not feel that the Captain did anything wrong morally. He has no moral duty to sacrifice himself for the people on the ship. There is a post on the front page now about a women who stayed on the ship and saved people while the captain got off. That is without a doubt admirable and I'm sure there were many people li... | 57 | As a merchant mariner who recently got his captains license, you're wrong.
What a captains license, aside from all the legal ramifications, really represents is that you are an experienced mariner; you know what you're doing. He made mistakes that put a lot of innocent lives in danger, and it's his responsibility to ... | 167 |
Is it true that there are as many numbers between zero and one as there are between zero and infinity? A math teacher made this claim and I'm wondering how it could be proven. | 18 | You do this by showing there is a one-to-one mapping between these two sets.
First, we pair every number x between 0 and 1 with 1/x. These 1/x will be between 1 and infinity. So this shows there as many numbers between 0 and 1 as between 1 and infinity.
To get the pairing needed to show what the math teacher said, we... | 26 | |
ELI5: The process and significance of "making partner" in a law firm | How does one become a partner? What changes? What are the advantages/disadvantages, if there are any? | 235 | It takes anywhere from 2 to 10 years to make partner at an average law firm (sometimes longer). In order to be considered for a partner position (while working as an associate), you usually need to work very hard and contribute a lot to your firm's business. It helps if you can pull a lot of all-nighters, find new clie... | 209 |
ELI5: What does it mean to argue in bad faith? | 16 | It means that you're not arguing to come to a mutual understanding. In a true debate/argument, both sides must be willing to acknowledge if the other side has good points and be open to changing their minds. If you tell someone you want a "debate" but you really just want to antagonize them or preach to them, you are l... | 21 | |
[Spongebob] How is the Flying Dutchman so powerful? | I know the powers of ghosts varies from franchise to franchise, but one thing that has always made me wonder is how is the Flying Dutchman so powerful, like he is nigh-omnipotent (He can grant his own wishes), how is he so powerful when he is just the ghost of a deceased person? Also when Spongebob and Patrick became g... | 47 | The Flying Dutchman is more than a ghost.
He might've been a man before his death, but now he collects the souls of the bikini bottomers, even officially since nobody questioned him showing up at the hospital to take Krabs soul.
So while he enjoys scaring the underwater residents and haunting the seas, his more like ... | 43 |
How do mosquitoes find water to reproduce? | I live near the Mediterranean, in a region where it doesn't rain 4 months a year, and we still get plenty of mosquitoes every summer. There is practically zero fresh water in the area, still or running. This leads me to think that mosquitoes aren't just flying around looking for water to lay their eggs through sheer lu... | 2,369 | Mosquitoes like many insects have incredibly sensitive sense organs in the form of antennae. These are able to detect a whole range of molecules including water. It's similar to us being able to smell but way way more sensitive.
Many mosquito species (such as aedes aegypti) will lay eggs in containers just above the ... | 1,865 |
If I'm playing my music at a volume of 8/10, would that use up my battery faster than if I played the music at 3/10? | Does playing something louder use more battery life? | 436 | It depends largely on the impedance of the headphones. Most headphones designed for portable listening are going to be less than 25 ohms. Headphones with larger drive coils tend to have higher impedance, and will take more power.
But for things like earbuds, the difference between 3/10 and 8/10 will be negligible. Th... | 170 |
ELI5: Why is it that when people read orders from others such as "you're now breathing in manual mode", they become aware of breathing and find it laborious? | I just read several comments telling people that they're now aware of their breathing, or that they've now got an itch somewhere on their body that they just *have to* scratch, or manually blink, and others below are cursing the guy out for making them feel uncomfortable.
Why do people become "aware" of these facts, w... | 21 | All of the functions you describe are semi-autonomous. Normally, your body just kind of takes care of blinking and breathing by itself, like it does with your heart and digestive system.
The ability to actively control blinking and breathing has its obvious advantages, but the mere ability to consciously control them... | 14 |
ELI5: What's the purpose of the cartilaginous tab over the ear hole? | Most people's ears have a cartilaginous tab that fits right over the ear hole (to block it), if you presse with the finger. Safe to say that's the purpose it serves? | 62 | Update: ok, after learning from a video that the floppy part of the ear is called the "pinna" it made me want to dig around to find what the name of that "tab" is, and turns out it's called the "tragus". Now armed with a googleable name, the search was on, and it appears that the tragus does aid in collecting sounds f... | 19 |
[Futurama] What does Bender do with all the cash and swag he steals? | Bender loves stealing and taking things. Plus he's got a minimum wage job as a ship's cook. We've seen him steal millions in cigars, jewels, swords, cash, various swag etc. So what does he do with it all?
Is he paying down a pay day loan from when he was younger? Child support? Legal fees? Save it for a rainy ... | 103 | On a day to day basis when he has small scores he spends it on booze, cigars and prostitutes.
When he has a big score and has a lot of money, he spends it on really fancy and expensive booze, cigars and prostitutes.
Anything left goes to ass shining sessions and occasional purchases of robot pornography.
It's also... | 129 |
CMV: Big tech (Google, Facebook, Amazon, Twitter, etc.) should be collectively owned and democratically controlled by all its human users | Monopoly is natural and inevitable for data giants. If your 'product' is simply the flow of information, the only feasible business model is to be pretty much the only player in a given market. Humans must recognize that data giants are creatures fundamentally different from, and superior to, brick and mortar corporati... | 15 | This is an inefficient, pointless plan.
Nobody wants to vote for who's in charge of their local server hub. 90% of users will just never vote (look at the ratio or lurkers here now). Low voter turn out is a great way to get high dissatisfaction.
The attention of the voters is a fundamental limit to democracy. Tech co... | 14 |
ELI5: If symptoms of being sick (mucous, sore throat, fatigue) are immune system responses, what does the cold virus actually do? | 4,046 | While your immune system is fighting them, pretty much nothing. However, if they were allowed to keep reproducing without a fight, then they would just keep killing off cells at faster and faster rates, eventually preventing vital functions from working and killing you. | 3,263 | |
Inflation a lie? | I have noticed that a concerning growing amount of people believe that the current state of inflation is a fallacy, since companies are 'making record-high profits,' implying that companies are increasing prices out of pure greed. This is further exacerbated by politicians (who I won't name) spreading those beliefs. Wh... | 59 | Inflation is a sustained increase in the general price level.
That's it. Does the price level go up? Then you have inflation.
Doesn't matter if that happens because producer prices go up thanks to supply shortages or because someone's wish from a genie is for prices to go up, inflation is very much real completely in... | 123 |
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