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e4gx6y | Biology | how does cancer kill? | Cancer takes a cell that is supposed to do a certain job... And makes it misbehave and join it's tumor. Imagine if your heart was a factory filled with human workers. Those workers represent cells in your heart. Now one of these workers goes rouge and starts walking around and not doing his job. He then starts converting other employees to not do their job... And follow him. Eventually, there's a tipping point where there's not enough workers to continue a working factory and things get jammed.. broke.. maybe even a fire and the factory.. your organ, fails. | 1 |
c6kqmg | Physics | How do weather forecasts calculate the "feels like X" temperature? How can a temperature feel like another temperature? | When they give a temperature, that is the "true" temperature. The thing is, when you are outside there are more things that matter, such as the wind and humidity. This does not change the actual temperature of the air, but it does change how it interacts with your body. First, imagine you outside and there is absolutely *no* wind. It is 20 degree celsius. Your body temperature is 37 degrees. Now, this means heat will flow from your body to the air. This is how thermodynamics works, heat will flow from high temperatures to low temperatures. The thing is, the bigger a difference in temperature, the faster heat transfer happens. Why is this important? Well, because when you heat up the air just around you the temperature difference is gets smaller, thus slowing down your heat transfer. Imagine the air right next to your skin will be more than 20 degrees and then it decrease the further away it gets until it is at the 20 degrees that it is outside. Think of it like a little bubble of warmer air around you. Well, what if we introduce wind? You still transfer heat to the air around you, but the wind quickly circulate it away and new air is now around you. This means the temperature difference is always at it's highest, you never get to heat up the air. Essentially, your "warm bubble" of air can never form, because the wind keep pushing it away and gives you new air. So in both scenarios you have 20 degrees outside, but how it interact with your body is much different. In general it is wind and humidity that cause the difference in actual temperature and what it feels like. | 2 |
gkrowf | Other | Why is vinyl coming back into fashion again? | I like having physical copys of my favorite albums and displaying the cover art. Im only in my early twentys so theres no nostalgia associated with vinyl for me. Also it's a forcibly linear way to listen to albums which is nice in todays times | 5 |
hipxsz | Physics | Do perfect mirrors exist? Could you trap photons in a perfect mirror container? | Light *refraction* turns out to be the key to total light reflection on a surface. It's not really a mirror by definition, since the [total internal reflection]( URL_0 ) depends on the light's angle of incidence. It's the basis of fiber optic cables that can transmit pulses of light through snaking twists of a thin cable, across the Atlantic Ocean floor, for high speed data transfer. Transmission isn't optically 100%, but good enough for thousands of miles. To go beyond ELI5, there's also the issue of the lack of "sameness" of photons after interacting with matter. But that's too far afield. So the tl;dr answer is: no perfect trap for photon energy, but close enough for our needs. | 1 |
5uzmsa | Biology | If only about 10% of energy is passed up each trophic level, why is meat so much more calorie dense than fruits and veggies? | The two statements are not related. Think of your question this way: "If John has 1000 lbs of rocks and gives me 100 lbs (10%), why are my buckets heavier than his?" The answer, of course, is John carries his rocks in 10 lb buckets and you carry yours in 20 lb buckets. The fact that he had more rocks to start does not have any bearing on how many rocks you put in your bucket. So the answer to your question is that the amount of energy moving up the trophic level doesn't matter. What matters is how that energy is stored. And animals store their energy in more saturated fatty acid chains, which are more calorie dense than how plants store their energy. | 1 |
m4rjai | Technology | How do graphics cards actually work? The title says it all. How do they work? I never fully understood how they did. I know that they help to render and display images, but how exactly? & #x200B; Edit: Thanks for all of the great replies! You guys really helped me to understand what exactly a GPU does, and why it's needed. | CPUs are built for sequential calculations. What that means is basically that for your calculations, you have some steps you need to go through, and you cannot do one step before all the steps that came before have completed. That is why CPUs usually have a handful of cores (just one for the longest time, though currently they are usually in the 4-8 range for desktop computers, maybe 2 for the low end and 16 for the high end - though servers or workstations can go above a hundred nowadays). However, those cores are really fast at going through the steps of a calculation. However, when you look at an image, the calculations needed to create an image are not all like that. You have a large area where tons of similar calculations need to be made, for example things you need to calculate for every pixel of your monitor or every object that appears on screen. And the bottom-right corner depends no less on the top-left corner than the top-left corner depends on the bottom-right corner. So you are not limited to calculating everything in a fixed order, you can do calculations for multiple areas of the image at the same time. That is why GPUs are built to have thousands of processing cores (the fastest consumer GPU on the market, the GeForce RTX 3090, has about 10000 cores - the CPUs it would commonly be paired with, such as the Core i9 10900K or the Ryzen 9 5950X, have 10-16). Each individual core is quite a bit slower than a CPU core, but because of their sheer number, there are certain problems, especially those that can be divided up almost arbitrarily into mostly independent calculations, that it is faster at by just a ridiculous amount. | 4 |
b1gazh | Economics | How do you read a stock chart? | At any given instant of time, a stock has a certain price. This is the amount of money that changed hands the very last time that someone sold one share of that stock to someone else. Because of the way the markets work, this represents the real value of the stock. If I met up with you in a bar and tricked you into buying one share of my JunkCorp stock for a thousand dollars, that doesn't mean that $1000 is the real stock price, for this discussion. Most of the numbers you read on a stock chart are just looking at this price at different points in time or in different ways. You commonly see the Open (what the price was first thing this morning), the High and Low (the extremes of the price for today), the 52-week High and Low (the extremes of the price over the last year), and the Previous Close (the price when the market closed last night). Prices can change overnight in what's known as after-hours trading, but for the most part prices move around only when the market is open. Different markets have different open and close times. A few numbers are not as straightforward. blipsman described the P/E ratio. The Market Cap is the total value of the company, equal to the current price of the stock times the number of shares of stock that exist. Note that without knowing the number of shares that exist, the stock price really doesn't tell you much about how "big" the company is. A hypothetical company with a stock price of $1000 but only 100 shares in existence is far smaller than one with a stock price of $50 but millions of shares in peoples' hands. The last number you see if for example, you Google "IBM stock quote" is the "Div yield", or dividend yield. A dividend is money that is paid out to stockholders by the company. By holding onto the stock, you receive a share of the profits of the company, which can be sent to you annually, semi-annually, quarterly or monthly, usually. The dividend yield is the amount of this dividend (per share) divided by the price of the stock (per share). So if the dividend yield is 5%, the stock price happens to be $100, and you own one share of the stock, then you can look forward to a $5 check in the mail. | 2 |
j6q7xj | Technology | How come TV remotes are still so bad? | Is percussive maintenance another word for smacking it? | 15 |
iohvt5 | Other | Unincorporated Communities What are these? I went on a trip this holiday weekend and kept seeing green signs with a community name with "unincorporated" under it. | It means means that community is part of the county but not within city limits, and may not be big enough to become its own town. | 2 |
99vhyv | Other | how are purchases correctly identified as fraudulent by credit card companies when there is nothing “unusual” about them? By nothing unusual, I mean a charge within a spender’s typical budget amount and relative location. This happened to me recently, and in discussing my relief with friends, they also mentioned having charges correctly flagged by credit card companies. Conversely, if a person is traveling and a card doesn’t require travel notifications, how do the auto flags know those travel charges are legitimate? | I worked in a regulated industry and can provide a little bit of insight. In a nutshell, it's all about data. Your personal activities are but one data point (one piece of sample data) from a collection of data spanning millions or even billions of transactions. After a while distinct patterns emerge in that data and analyzed to determine when fraud is present (and given a score) , your individual spending pattern is only a very small part of it a very big picture. some times the pattern is introduced from transactions that happen from known stolen cards, like a script that tries to validate card numbers, or simply the terminal ID of the transaction source (the cc machine on the store counter) could be suspect. Or even simply by location and type of use (there is a card test that uses a card to buy something on amazon and sends to a random address). At the end of the day, there could be millions of data points that contribute to scoring a fraudulent purchase or activity as a hit and then the system compares it against other factors at a large scale, comes up with a final score and then flags accordingly. The systems are mind numbingly accurate and get more accurate every day. The data collection system I worked with had an accuracy rate in detecting fraud across a sample set of over 100 million transactions a year that was only incorrect in its scoring system less than a dozen times, all but 2 were false negatives (meaning the fraudster got away with it twice before that hole closed). I don't know if that was ELI5 worthy, but it was as generic as I could make it. Also on mobile, so sorry if my sentences are a mess | 3 |
65c6pu | Culture | How does Jesus's death allow all humans who worship Jesus to be forgiven from their sins? | Nietzsche said it was Jesus enslaving us in guilt for all eternity. He did something we didn't ask for so that we would be beholden to him forever. | 4 |
83cvr4 | Other | From my actual 5-year-old: "How do you know that the world is real?" | I think therefore I am. It's impossible to say that this is not the Matrix. Older than the Matrix is the brain in the jar thought experiment. You might be a brain in a jar. This is a simulation. Everybody takes the blue pill. | 5 |
il5ptb | Biology | why do humans need to eat many different kind of foods to get their vitamins etc but large animals like cows only need grass to survive? | Wild deer sometimes eat dirt, well if they can they find a salt lick. But they still go looking for minerals not found in the plants they eat. They also occasionally munch baby birds. Possibly other small wildlife, but I know about the birds. It’s a bit like the way a dog or cat sometimes eats grass. | 28 |
70sgiu | Technology | How are vector illustrations not based on pixels if our screen is made up of pixels? From my understanding, a pixel is the smallest distinguishable unit on a digital monitor. So how can a vector not be pixel based? Isn't everything that's on our screen made up of pixels? So even if we're using a software like Adobe Illustrator, isn't a vector line made up of a bunch of small pixels in actuality? | Say you take a photograph of your cat and you develop that photograph. When you look at the photograph, it looks realistic. But if you zoom in on the photograph, you'll start seeing pixels. However, if in real life, you simply move closer to your cat and take another photograph, you'll now have a "zoomed in" version of the cat but with much more detail than the original photograph. Vector graphics are like the real-life cat. The photograph is a representation of the cat (the pixels drawn on the screen). The vector graphics, as well as the cat, have infinite detail, but the representation (photograph) does not. If you were to draw vector graphics on the screen and zoom in, *without redrawing the vector graphics from scratch*, you'll start seeing pixels. The idea behind vector graphics is that you keep redrawing the infinitely detailed vector graphics in pixels on the screen, thereby giving infinite zoom and details. Basically, you're taking a new "photograph" every time. | 3 |
9i0swk | Culture | Why is the passive voice seen as "bad"? How is it any different to the active? | Passive voice is usually really boring as a storytelling technique. If you are writing a scene with action in it — not an action scene, to be clear, although those count as “scene with action” — you want the reader to keep reading. Passive voice doesn’t charge the emotions like active does, and most fiction is intended to create an emotional response which engages the reader and compels them to keep reading. Passivity is good for summarizing events over the passage of time, but isn’t compelling for telling a story as a moment is unfolding. In a fight scene, you want your sentences to reflect the speed of the action: quick, intense, immediate. Passive voice is usually more loquacious, in addition to not being very helpful at tension building, so again: not great for action. It depends on what you are writing, though. Passivity can, when handled well, be horror inducing. Something which is frightening precisely because of how apathetic it is — eldritch horrors, forces of “supernature”, even medical description — will benefit from a well applied passive voice. Even then, a piece of fiction written as a medical record is probably going to have some decidedly nonmedical active voice for the sake of drama. If a story is mostly told in a passive way (I say, very generally and hyperbolically), there is probably something else compensating for the absence of linguistic action. Like art. (I want to say The Gashlycrumb Tinies has some examples of the art filling in some gaps in the story, but it's been a minute and I’m not 100% certain.) If you want to create emotional distance in your writing — to summarize, to emphasize the intellectual element, to create a framework or setup — passive voice is very helpful. It’s frowned on because too many people use it for straightforward storytelling and it's become a hallmark of amateurism. | 4 |
6ptx5e | Economics | Why do so many American TV shows & movies film in Canada? Does Canada look more "American" than the actual USA? | I think it has more to do with economics than esthetics and authenticity. As I understand it, Canada offers fairly generous tax breaks to production companies. That said, if I hadn't known from looking it up I might never have guessed that TV shows such as *Smallville* and *Arrow* were filmed there. | 5 |
7viwag | Other | How do those dieting programs like Nutrisystem work so that you lose like 20 pounds in just one month? The foods all seem like pretty high carb, high fat foods so how is it possible that people lose so much weight by eating them? | In addition to what u/Nessuno_Im said, notice that the ads usually say in the *first* month. When starting a diet, weight loss can be quite rapid in the beginning compared to the effort put in. With the set portions and calories, it's easy to lose that much in the first month. That weight is also usually not 100% fat but mostly water weight, As time goes on, the weight loss becomes more reasonable and steady. In fact, the Center for Disease Control recommends losing, at maximum, 2lbs/week as rapid weight loss can have ill affects on the body. | 2 |
o6by0u | Chemistry | When you shake a carbonated drink (soda/beer) it will fizz out of the can if you don't wait a while for it to settle down. What happens to "settle it down"? | It's often said that shaking a bottle or can of a carbonated beverage causes the pressure to build up, so that when you open it, the beverage explodes. This is a myth. Assuming the container wasn't recently re-sealed after being depressurized, the pressure will not change inside. A carbonated beverage is filled with dissolved gas. Carbon dioxide, to be specific. They can force more of it in there at higher pressures, so the can or bottle will be pressurized when you first open it. After releasing pressure for the first time (that first *fssst!* sound when you crack open the seal) all the trapped carbon will want to come out. But the gas is mixed in all over the liquid, and it can only escape at the surface, which is a very small area, so the drink "goes flat" relatively slowly. What's really going on when you shake the beverage is you're causing very tiny little bubbles of trapped gas to get stuck all over the inner walls of the container. By doing this you're basically increasing the surface area of the liquid contacting air and spreading it all throughout the container. Release pressure when the container is like this, and suddenly trapped carbon dioxide all over the drink has a short path to escape all at the same time. This causes all the tiny bubbles to grow quickly and explosively at the same time. The opening on the container funnels all of this foam through a single opening, causing it to spray out with considerable force. By waiting a while, all the tiny bubbles stuck to the walls of the container eventually unstick and rise to the top. If you get rid of these bubbles, you get rid of the foam explosion. Life hack: flick the sides of a shaken carbonated beverage container with your fingers. This will knock the tiny bubbles off of the walls and make it safe to open right away. | 2 |
hmhi4j | Technology | Why do blacksmiths need to 'hammer' blades into their shape? Why can't they just pour the molten metal into a cast and have it cool and solidify into a blade-shaped piece of metal? | Everyone is going into crystal structure, which is not really what stops blacksmiths from casting iron or steel. The main roadblock is just that it's really fucking hard to cast iron. The melting point is extremely high, (I've only successfully melted it once, and that was using coal, an electric blower, and modern refractory insulation) and before the advent of modern refractory materials, it would have been nearly impossible to work with. Even today, it is many times easier to just work a pre-cast piece of steel into the shape you want than to heat it up past 1500°C and re-cast it. | 20 |
m8hpj3 | Technology | Why do liquor bottles sometimes have those thing that make it pour really slow? | This is a bit broad. Are you referring to pour spouts as seen in bars and restaurants, or the plastic built into the opening of large bottles? | 6 |
an1pm4 | Biology | What causes us to have a "sneeze number", where we normally sneeze only a certain amount of times in one go? | I don’t know why, but I always sneeze in 3’s. Sometimes all three come at once, sometimes I sneeze twice, then the third comes a minute late. 🤷🏻♀️ | 2 |
604xug | Biology | When observing animals across the globe of the same species; there are a vast number of stark contrasts in appearance and traits. Why is it we don't see so many cosmetic/ fundamental differences with Humans? | White, black, brown, tanned. Hairy, practically hairless. 6 eye colors. Short, tall. Muscle definition inclined, and not. highly intelligent, not and in-between. High metabolisms , and not. Some have a natural endurance to cold, or heat. Some suffice with little nutrients while others don't . Hair color. These are just off the top, many other variations between us. However, to answer why you perceive it as such is because we see our similarities before we see our differences with our own species, you don't have any predisposed biases with other animals. Lastly, we have been a higher developed species for a long time and we never had the extreme separation from each other like other animals. Look at chimps, they are a highly developed social animal, and there are different tribes, races if you will, they have significant differences but not as extreme or as noticeable. | 1 |
m0e71g | Technology | What is the difference between digital and analog audio? | Analogue audio is stored in an analogue (continuous) medium such as vinyl or magnetic tape (audio cassette). Digital is stored in a discontinuous medium such as a CD or MP3. Sound is a wave, so audio information just describes the shape of the wave. On vinyl there is a wavy groove which has that shape, on cassette there is a varying magnetisation of the tape which also has the shape. ~~On a CD the "height" of the wave at each moment in time is assigned a value from 0 to 255~~ *~~65535~~*~~. Then at the next timestep it has another value. So the true wave shape is approximated by a sort of stepped shape. See a comparison~~ [~~here~~]( URL_0 )~~.~~ *A digital signal on a CD stores the wave form as a series of values at moments in time, with those moments very close together. Think of a series of dots where if you squint you see the original curve. There are 65536 possible values, stored every 1/44100 seconds, which is all you need to replicate the original sound when you play it back.* So long as there are enough values ~~and short enough timesteps~~ the digital shape is a close enough approximation to the true shape that no human can hear the difference. MP3 and other digital formats go further and compress the audio, so they sort of describe the shape rather than simply approximating it as outlined above. This can lead to distortions that humans can hear (or claim to). You might think that analogue is therefore 'perfect' in a way that digital cannot be. This is sort of true, but any real analogue medium will have physical limitations which add their own distortions to the sound, potentially to a greater extent than good digital audio. *Edit to add: yes I am aware that a digital signal perfectly replicates the waveform up to the desired frequency, thanks for all the reminders.* *Edit 2: alright alright I get it. People have strong feelings about this analogy.* *Edit 3: actually scrap that I stand by my statement that a digital audio signal is an approximation of the original. Sound is not band limited, and does not have finite bit depth.* | 17 |
bar3zq | Biology | How do animals live without dental care their whole life when we humans cannot live without cleaning our teeth everyday? | We technically can survive our entire natural lives with no dental care, if any animal lived as long as we do they wouldn’t have teeth like we do. Plus animals typically don’t eat any acidic, sugary or extremely hard food items that they aren’t adapted to eat Basically if without dental care you can have teeth until you are 65 but only live on avg to 30 then it doesn’t matter | 4 |
602j30 | Repost | Why is 24 FPS unplayable in video games, but looks fine to me in movies/TV shows? | When you play a video game, you are thinking of an action to take, you take the action, and you expect instantaneous response from the game. When I'm playing rocket league, I think "hit the ball now." I press the A button and move my thumb stick forward. If the car doesn't instantly flip forward due to lag or whatever else, it's incredibly obvious that something didn't work out. In a movie, you probably don't have any idea what's about to happen and there is no input required from you, so you are a passive observer. | 10 |
ck2eh1 | Biology | how low pain tolerance and high pain tolerance works | People with chronic pain have the highest tolerance because they have to learn to live regular lives... take care of kids, go to work. We smile and laugh at the birthday party while looking at the clock wondering when it’s going to be cool to slink away and to get home and cry in the shower alone bc sweet baby Jesus the hot water is a relief at least while you’re in there. The truth is nobody wants to hear about it. It’s not a comfortable topic & it’s not something you can see like a broken arm, etc and it’s too difficult to understand without experiencing so we just keep it to ourselves or our closest people. I often have no idea if I’m sick or not. I ended up in the hospital with scarlet fever and the nurse kept asking, “why didn’t you come in sooner!?” Because I didn’t get a high fever until now and that was the only way I had to know I was genuinely sick and not just my normal pain. Had strep for days without a clue. But mostly I just wanted to add to this thread that I recently started ldn and am having good results. I think it’s something anyone with chronic illness/pain/autoimmune issues should look into. | 25 |
ae3pua | Biology | How does radiation therapy kill cancer cells and does it kill normal cells in the process? | radiation is basically high energy waves, such as x-rays. you focus it at a spot and it kills all the cells. healthy cells are gonna be killed as well since there's no way to aim so precisely and also as a method to control the progression. treating cancer can be like battling a wildfire, sometimes you have to burn healthy/tissue land in order to stop the fire/cancer from spreading. | 3 |
9j2wki | Economics | What is the difference between Country A printing more currency, and Country B giving Country A currency? I understand why printing more currency can lead to inflation, but am confused about why the second scenario does not also lead to inflation. | the second scenario can lead to inflation, in scenarios where the 2 country's don't trade frequently. in essence, if the money coming into country a isn't offset by money going to country b, A will be inflated. the best example i can think of is Country B paying A for some debt they owe, but a bunch of A's money ends up in B due to tourism or something. as long as input and output are roughly consistent, there's no issue. but if no1 from A goes to B, then A will be inflated from B's money. | 14 |
avpof1 | Other | Why does PETA even kill animals? | Domesticated animals cannot be set free because they do not know how to fend for themselves. They can't hunt and don't know what is dangerous and what isn't. So if let go they would most likely suffer, starve and die. But PETA is against keeping any sort of animal no matter what so their logic is its kinder to kill the animal than release it to suffer. | 2 |
9z72gl | Biology | Why is pain more tolerable when it’s self-inflicted? | I'm not a doctor or anything but I believe it's a control thing. If you think about it, when you're in pain no one moment is the intolerable part, it's the fact that it's not gonna go away. When you're inflicting it upon yourself you have control and can stop it at any point | 1 |
bbzomk | Engineering | If you keep turning on and off a light/lamp it may "break" and not work anymore. How does this happen exactly? | Old lamps emit light by having electricity course through a very thin wire, heating it to extreme temperatures. This causes it to emit light. But heating/cooling it too much puts stress on it, and it can break. When it happens electricity can no longer circulate, and the lightbulb is broken. | 2 |
huje0y | Biology | How does intuition or our ‘gut feeling’ work? | For me, I believe its all the experience I've had in my lifetime, even though I can remember half the shit I've been through its still I'm my subconscious mind and it pops out a lot when needed. | 2 |
7w0wft | Other | How does a "nationwide saline shortage" occur? | It's sterile salt water. In practice, there are a lot of requirements, and while anyone can make it, only a few companies are certified to do so and many hospitals only buy through specific sources that only use specific manufacturers. For the saline shortage, a hurricane caused a large manufacturer to shut down, and the other companies may have had trouble ramping up supply quick enough to cover for that shut down. | 3 |
7uz507 | Chemistry | Just how much less nutritious is food that has been frozen such as frozen fruits/meals | Calories should stay exactly the same. Mineral content will also be exactly the same. Some vitamins can be changed by various environmental factors including temperature. Vitamin C, for example, is degraded by exposure to oxygen. Freezing can actually help protect against oxidizing since liquid water more efficiently transports oxygen than frozen water. I honestly don't know chemistry details on most of the other vitamins, so hopefully someone else can weigh in there. Freezing will primarily change the texture of food. This happens mostly because cell walls and other microstructures in the food get destroyed by the expansion and crystallization of water when it freezes. This is why thawed frozen fruits are almost always more mushy than fresh fruits. This destruction will make the food degrade *very* fast after the food is thawed. This is why most frozen foods are meant to be eaten directly after defrost and often instruct you to avoid refreezing them. With frozen meals, the makers know that freezing will change textures to be less palatable. This is often alleviated by making meals that are heavily dependent on sauces which usually means adding considerable salt and simple sugars. Carb-heavy foods like potatoes are also more likely to reheat deliciously than most meats, fruits, and some veggies. This can make frozen meals tough to fit with some diet goals. | 7 |
b1bsql | Other | Why so many people are claiming that space, satellites, (and planets) are fake/CGI | Because the same reason religions are a thing, if you tell a lie long enough people will believe it. they just came up this this "proffs" that kinda make sense but if you take the time to think about it and do research you will find that they are just wrong. And the sad thing is that " kinda makes sense" if often enough for people to believe in that stuff. | 4 |
awdxia | Other | Why are eSports so much more popular in South Korea than other places? I've been watching a lot of Overwatch League and one pretty apparent thing is that a ton of players come from South Korea. I've heard the explanation to this is that eSports in general is extremely popular in South Korea. Is this true? If so, why aren't they more popular other places? | Their culture is much more accepting of gaming then most of western culture. Especially when it comes to gaming as a career. They even have college courses on how to be a pro gamer. In a place like say the U.S though gaming still has a stigma as being for kids and or lazy people. Taking a college course on gaming would be seen as worse than flushing money down a toilet and make it harder for you to get a job. It's still not seen as a viable way to provide a living for ones self. That's slowly changing with the rise of things like twitch and gaming on youtube but it's still far from being like it is in SK. Also take into account that SK is a tiny and relatively isolated country this allows gaming to be a viable path for a lot of people there. In a much larger country though you're gonna have a hard time having it be a viable path more than a small amount for people. | 3 |
htl9hk | Other | My daughter just asked me “If outer space is black, how is the sky blue?” Help me explain it please. | Misleading stuff in some other answers here. Some past posts of this same question have had better answers. * Edit: Some good explanations are now bubbling up to the top for this post. The blue sky is the result of the physical light-scattering process called [Rayleigh scattering]( URL_1 ) in our atmosphere. As a point of comparison, when light shines through the vacuum of space, there's nothing to change the light's path. Light goes directly from the source to your eye. If there's no direct line to a source, there's no light there. The blackness of empty space between celestial objects. But our planet has an atmosphere. The atmosphere stretches miles above our heads. The molecules in the atmosphere don't let all of the sun's light pass straight through in a direct line. Some of the light interacts with the molecules, and causes the sun's light to scatter off in different directions. It's not the same phenomenon as shining a flashlight at smoke puffs or fog, but that mental image can help build intuition. In Rayleigh scattering, the bluer colors of light are scattered *more* than the longer redder wavelengths of light, so the bright sky has a blue tint. During sunsets, we see sunlight that has had to pass through a greater distance of atmosphere to reach us. That means much of the bluer light has already been scattered before reaching us. The remaining sunlight at sunsets is therefore more orange & red. Deep red skies can happen when sunlight scatters off of larger particles [such as smoke and pollution]( URL_0 ). | 6 |
9lx1zl | Culture | Why does it cost money to get elected to office in the US? | Paying staffers, buying ads, paying for travel to make public appearances, cost of paying for a space and security for a rally or other event, paying to print out yard signs, posters and flyers, etc | 5 |
hh96it | Physics | why do disposable razors with 5 blades not cause razor burn compared to a razor with 2-3 blades? | Good blades and good shaving practices will usually help you avoid razor burn, moreso than the number of blades. But generally speaking, pulling, tugging, and scratching are the basic causes of razor burn. This can be on hair or skin. Friction is one of the main reasons why this happens. While increasing blades increases the friction, it also increases surface area. This increases surface area decreases pressure placed on the skin at any one point of the blade, making it run smoother. Think of using your fingernail to scratch versus using your fingertip. Your nail is much thinner and applies that pressure in one specific spot, whereas your fingertip spreads that pressure over a larger area. Perhaps the other important reason is that more blades increases the amount of hair that can be trimmed and stuck in the blade, decreasing the need for passing the blade again in the same spot (means less dry skin to blade contact). This also helps the blades to not wear out as quickly (less usage each day). | 2 |
6tyd10 | Mathematics | How can one infinity be larger than another infinity | Unfortunately, at some point you just need to say "it works that way because math." To try to explain this, you need to understand *sets.* A *set*, in math, is a group of values. In this case, we'll look at the set of integers and the set of real numbers. An integer is just a whole number (1, 2, 3, etc). The *set* of integers is a group of *all* of the whole numbers there are. All the way from negative infinity to positive infinity. A real number is basically any number that doesn't involve the square root of negative one. Technically, it's an integer, a rational number, or an irrational number, but that's beside the point right now. The *set* of real numbers is the group of all of the real numbers ever. But those sets are very large. So let's look at some smaller sets right now. The set of integers we're looking at is {0, 1}. There are two elements in this set: 0, and 1. It's a set of size 2 (or, in math terms, the set's *cardinality* is 2). So let's look at the set of all of the real numbers between 0 and 1. So you've got 0, and 1, like you would expect. But you've also got 1/2. And 1/4. And 1/8. And 1/68661068672681. And so on. In fact, there are an *infinite number* of *real* numbers between the two *integers* 0 and 1. The set of real numbers on the interval of [0, 1] is *infinite in size.* But think about this. There's an infinite number of real numbers between any two integers. And there are an infinite number of integers. *That's* how one infinite set can be larger than another. The set of integers has an infinite number of items in it... but between every two of those items, the set of real numbers has an infinite number of items, too. Both of them have an infinite number of items, but one infinity is much larger than the other. EDIT: I know. I get it. This is ELI5, not ELI'm pursuing a PhD in math. Here's a better explanation that still boils down to "reals have a bigger infinity than countable numbers": > URL_0 | 2 |
90g563 | Economics | How do franchise owners like 7-11 or McDonalds deal with corporate promotions like free slurpy day, or free french fries. Do they just expect the franchise owner to absorb the cost of some idea an executive came up with? | In the long run, a promotion helps you sell more. The point is not just give away free stuff; the idea is that by saving some money,the customer will end up spending more money after luring them with the freebies. Just yesterday I went to buy nachos at some store. It was a hard choice cause there were also some chips that seemed particularly alluring to me, but I didn't want to spend too much. Anyway, I got my nachos, and it turns out there was a deal: Get a snack at full price, then get the 2nd one at half price. I asked if I could choose any of the snacks and they said yes. Walked out happy with both nachos and chips! It won't work with everyone. Some people will get their free stuff and run, but most people are ready and willing to treat themselves, and if that means saving on fries to get a bigger burger and possibly an ice cream, then why not? | 33 |
aes37j | Technology | How do different types of brain scans work and what is the difference between them? EEGs are pretty straight forward but what purpose do MEGs, CT scans, CAT scans, MRIs, and PET scans serve, how does each imaging machine work, and what is the difference between them? | MEG scans work by mapping the magnetic fields produced by the electrical currents in the brain. It can measure brain activity in specific regions in real time. CT and CAT scans are the same thing, CT scan is just the more modern, commonly used term. This machine uses x-rays just like a regular x-ray machine but it takes them in "slices" to produce a 3d image of the body part in question (not just the brain). MRIs use powerful magnets and radio waves to make 3d images of the body (again, not just the brain). A powerful magnet aligns all the water molecules in your body in the same direction. Radio pulses disturb the alignment, and detectors measure the rate at which the molecules revert to the aligned state. Different tissues have different amounts of water so they align at different rates, and this translates into images. a PET scan works by injecting the patient with a small amount of a radioactive tracer chemical. When radioactive things break down (decay into lighter elements) they emit positrons. When positrons hit a electron (it's negative) they annihilate and give off some gamma rays. The PET scanner can detect these rays and form an image. | 1 |
7jkx5v | Biology | How does your mind choses random numbers when someone asks you to do it? | There is a concept known as [priming]( URL_0 ) where observing something, consciously or subconsciously, brings it closer to the front of your mind. For a little anecdotal evidence, the first number I thought of was 23. I noticed going back to the ELI5 front page, there was a post that had a score of 23 points. That subliminal number that I did not notice at first very well could have influenced me. In rock-paper-scissors, there are certain "tells" that are based on priming. For instance, from watching a competition, one of these tells they mentioned was that short-haired women are more likely to pick scissors, having seen more than their fair share of them. | 6 |
cpj24v | Biology | Why do SSRIs take up to 2 weeks to kick in, but only 2-3 days to wear off? | Imagine an empty swimming pool being filled with a hose. To be allowed to dive, you must fill the pool to the 8 foot mark, so you put a plug in the drain. It takes many hours to fill up 8 feet of water. The water level needs to rise 8 feet, to reach the 'effective level'. It's now 8' 1". Someone removed the drain plug. The water level only needs to fall more than an inch before it goes below the 'effective level, where it's not allowed to dive. Also, the drain is letting water out faster than the hose brings water in. So it only takes a few minutes before it's not safe to dive again. In this analogy, the SSR inhibitor is the drain plug. | 2 |
7ip7ke | Repost | the difference between 4 Wheel Drive and All Wheel Drive. Edit: I couldn’t find a simple answer for my question online so I went to reddit for the answer and you delivered! I was on a knowledge quest not a karma quest- I had no idea this would blow up. Woo magical internet points!!! | A truck that is capable of 4WD is usually a rear wheel drive vehicle for road driving until you lock the front diff. The front and rear diffs are usually locked harder than an AWD and will suffer on sealed surfaces for it. A Subarus diff (for instance) will have a baseline front and rear balance for power delivery. I.e. at 5% throttle it acts like a FWD, 20% throttle you'll get 10% of power to the rear wheels. When you floor it the distribution looks something like 60/40. The front and rear diffs are designed to be engaged at all times so can move to allow differential rotation. An AWD is supposed to be AWD at all times and is designed as such. A 4wd lets you choose how the powertrain operates based on your situation, and is not designed to be perpetually engaged. Hope that makes sense. | 21 |
eiy5c4 | Biology | How are the positions people are in in Pompeii so perfectly preserved? I would think that the force of the volcano, the limpness of death, the impact of the ash, etc etc would have caused people to be forced out of their positions. For example, there are supposedly people having sex, kissing, jacking off, sitting on a table etc... but are these just what we assumed they were doing? Or did the volcano completely preserve them that way? Thanks | The deaths were instantaneous ant the bodies went into a sate of thermal shock, which tightened muscles rather than relaxing them. This caused the bodies to have their position fixed at the time of death. The ash cloud which followed preserved the bodies afterwards. | 2 |
bu7iw3 | Technology | Why is Starlink internet supposed to be good, when all current satellite internet is hot garbage? | Current i tenet satellites are at 22,000 miles above the planet in orbit. Starlinks will be at 823 miles. Much less transmission time. | 2 |
hwzjn5 | Biology | What is the purpose of trees producing edible fruit, when all they need is just to make seeds. | My understanding is that this helps to ensure the seed is carried further away from the parent tree by animals that consume said fruit. Another reason may be that certain seeds require the acid in animals digestive tracts to remove their seed coats before germification. | 2 |
au1c3m | Technology | What is differential privacy? How does it work and Why is it important? I hear the term differential privacy being used more and more among techies. What is it? Why is it important, and how does it work? | Differential privacy has to do with how confidential information can be gleaned from seemingly obfuscated (disguised) information. Organizations like the US Census Bureau and the Department of Labor collect a lot of data about people under the condition of anonymity. This data is then published in aggregate to inform the public as to the state of the country. Theoretically, it is possible to go through these tables and, repeatedly cross-referencing one data set to another, to find confidential information that was not explicitly published. For instance, if you look up your local chamber of commerce information, it might give you last year's annual sales of goods by sector (food & beverage, hardware, gas, clothing, etc.). But if you also know that there is only 1 clothing store in town (or if this information is posted as part of the town directory), then even though the board did not explicitly tell you how much that clothing store sold last year, you can determine it from the information they gave. Differential privacy is concerned with how to carefully curate how data is published to prevent this. For instance, the chamber of commerce may simply omit the clothing section from their economic report, or roll it into a miscellaneous goods section. Given the enormous amount of data being collected and published every day on all different facets of people's lives, differential privacy is important to allow this data to be usable without compromising individual identities. | 1 |
7kwhos | Biology | Why do finger nails grow faster than toe nails? | I thought I read somewhere that the rate of growth of the nail is directly related to the size of the phalange. Fingers have longer bones than toes, hence they grow faster. | 10 |
5riufw | Other | Self Harming Why do some people have the drive to seek unpleasant physical sensations? I can understand people binging on instant gratification when they are depressed but I never figured out why some people seem to seek the opposite | Well first imagine every single day you feel like shit mentally, so in order to redirect the pain you cut yourself to move the mental pain to physical pain. That's the case sometimes, some people do it for attention too. (Source: Am depressed, no self harm though) | 2 |
fmu1bg | Biology | How is cancer so deadly but a person feels fine one day then the next they are told they have 4 months to live? | Just to add to the other answers, when a Doctor tells someone they have X amount of time, it's usually a highly educated guesstimate as there are so many unknowable factors based on the individual that affect survival rate. So you hear stories of "I knew someone that was told he had a week to live and he lasted two years" - the Doctor would have been making their prediction based on their personal clinical experience combined with data from studies in journals, etc. | 13 |
ft9nq8 | Biology | Given that the immune system is so "smart" when it comes to fighting new germs, why does it still go into panic mode every time it meets the same harmless allergens? | The immune system is "smart" in that it can recognize antigens it has seen before as well as new ones. The same systems are used for fighting allergens. Your body doesn't know the inflammation it caused almost killed you. Your immunoglobulins don't care you can't breathe. They have a job to do, and that doesn't change based on factors outside of their perception. | 3 |
f9qiyd | Economics | How do mega cities provide so many jobs when the cost of living is so high and they don’t have any natural resources to sell? With no natural resources and no manufacturing (since rent and costs are too big to sustain factories) that only leaves selling services, but how is that sustainable? | Consider Singapore, the services provided are expertise in engineering, software, information technology, tourism etc. But the main reason was in the olde days, when we were a British colony (and way back into the Mesopotamia times) Singapore was already established as a trading port due to its location at the fringe of continental Asia between east Asia and the West. Therefore bringing the people to come in, trade and replenish the stock for the next part of their voyage. | 5 |
5uz00n | Other | Is there any benefit to having ice cream prepared on a marble slab? | you find me mint chocolate chip cookie dough ice cream in a carton and I'll stop going to marble slab type places. (trust me, if you like both mint chocolate chip and chocolate chip cookie dough ice cream, it's awesome) | 9 |
hmhi4j | Technology | Why do blacksmiths need to 'hammer' blades into their shape? Why can't they just pour the molten metal into a cast and have it cool and solidify into a blade-shaped piece of metal? | The metal would be very brittle and snap easily, by heating and hammering the metal (folding) as well as laminating (layers of other metals/materials) you can increase it's flexibility while keeping it's hardness. Kitchen knives are a great example of this, to cut through normal every day items (say raw chicken or onions), you would use a chefs knife, large-ish multi purpose knife that is strong but a little bit flexible, when cutting joints or dismembering carcasses, you would use a boning knife, generally shorter than cooks knives, thicker and not really flexible, as you would use the knife to pry apart bones so you could cut the tendons, a flexible knife would just break. Then you have a filleting knife, usually about the same length as the boning knife, but about 1/3 as thick. This knife is very flexible so it can follow the contour of smaller delicate bones of, for example, a fish, allowing you to use little pressure so you do not damage the delicate flesh, but offering great precision and flexibility to do the job with 1 easy effortless stroke. When you heat the metal/s, you are weakening the bonds turning it from a solid to almost a liquid state, the hammering allows you to align the bonds how you need them (with a lot of practice and a damn good teacher), forming softer bonds for sharper edges, and harder bonds for blunt instruments. Really, all you need to know is that heating and tempering the metal make for a higher quality end product. | 20 |
5mjvap | Other | Why does everyone hate Breitbart news? | Because it's not news but unabashed propaganda, and often distorts the truth or outright lies. | 4 |
b4zd6d | Technology | How can a computer program written to play chess defeat world champion? Is it only because it is fast and can compute all possible moves? If yes, can a human defeat it, given infinite time? | Computer programs can be written to learn from experience just like humans can. And they can play many, many more games very quickly. Just like humans get better with experience, so can the program. | 2 |
l5v9id | Biology | Why do unhealthy foods like junk foods taste delicious and addicting while healthy foods like vegetables dont? | Sugar. Eating sugar releases opioids and dopamine in our bodies. This is the link between added sugar and addictive behavior. Dopamine is a neurotransmitter that is a key part of the “reward circuit” associated with addictive behavior. | 5 |
e9utut | Engineering | why are bathtubs always slightly smaller than an adult? basic common bathtubs are always specifically 5 1/2 feet long and 2 feet wide (ish), but wouldn't 6 feet by 3 feet make more sense, since humans are taller than back when bathtubs were made? | 1) You are not suppose to be able to lay down in a bathtub. They are designed for the average person to sit in them at an angle with their head and shoulders out of the water. 2) Bathrooms are designed to be as small as possible and still fit all the needed things into them unless you specifically spend the money to make a larger bathroom. As such once the standard size of tub was established that is the size a bathroom becomes. 3) In the US at least most people prefer showers so there is not a lot of pressure to change the standard size of a bathtub. | 3 |
i6dz8x | Other | In sprint events in the Olympics etc. some start at the back and some at the front, isn't that unfair? | The different starting points actually make it more fair. Someone running on the inner ring will have a shorter distance than someone on the outer ring, so the inner ring starts a bit further back. | 3 |
7oj5ab | Chemistry | Why does food change its calorie count depending on the cooking methods? So, 100 grs of egg (raw) is 143 calories, but 100 grs of egg (boiled) is 155 calories. How is that the calorie count changes just depending on how the food is cooked? I assume it is because the components or chemical links change and therefore, a higher amount of energy is needed to process the food, but I honestly have no idea if I'm in the right path here... Also, therefore for calorie count purposes (dieting), am I fooling myself a lot if I weight my food raw? What's the usual delta between raw vs. cooked? | When you cook an egg, a bit of the water evaporates out. This makes it denser, so 100g represents more egg. | 2 |
at0yjd | Technology | How can phones have 8gb ram in such a small formfactor and pc needs these huge 4gb ram stick? | This has to do with industry standards. The RAM slots on PC's are almost always the same size. A 64GB RAM stick is the same size as early 256MB RAM sticks. The size does not really represent the power/storage anymore. It's just a matter of standardization. Addition: RAM chips in phones are often integrated and can't be swapped. Cell phone RAM is also a lot slower. It consumes less power, which means it doesn't reach the same temperatures as the far more powerful equivalents in desktop computers. In larger chips, it is easier to distribute heat than in smaller chips, so a larger stick is beneficial for desktop RAM. And well... Desktops simply have the room for it. | 11 |
8z9b45 | Mathematics | When it comes to bullet calibers what do the numbers indicate? E.g 7.62x39mm, 5.56x45mm, 9x19. | Example: 5.56x45mm 5.56 means the diameter of the bullet 45 means the length of the casing | 2 |
9x5ux6 | Culture | foreign english speakers tend to have trouble with plural and tense, are these concepts unique to the english language? some other reason? I tried to think back to the tiny bit of high school spanish, and I think I recall that there were tense in that? as well as plural. What about in mandarin and japanese? Or is this just a random way that general unfamiliarity with a foreign language happens to present itself? | There is no conjugation in Mandarin, if you want to indicate when something happened you need to attach a time to it. What is most common is to state if the action is completed or not. That’s what the 了 is for. There is a linguistics term for languages that emphasizes if an action is completed but I can’t find it. | 9 |
657rqn | Culture | The possible domino affect of the recent US bombing in Afghanistan | There is no domino affect. The US bombed an ISIS target in Afghanistan. They have been doing this for a long time. Nothing new, nothing changed. | 1 |
d7ep5f | Biology | Why is it that animals are able to walk so much sooner (after a matter of days) than babies are able to walk or crawl? | It's because of our big brain. If our heads need to be big the rest of the body needs to be small to fit through the hole. Therefore our bodies are less grown. We also aren't threatened so we don't have to run the first hour. | 4 |
j1a1vc | Earth Science | What does this phrase mean: “Earth’s Ellipticity: Flattening at the Poles and Bulging at the Equator”. I honestly have no idea what this means, so any simple answer would be much appreciated. Thank you in advance to anyone who takes the time to answer! | You have an earth shaped ball made of playdoh the size of a golf ball. You put your thumb on the South Pole and your index finger on the north. Squeeze gently. The middle (equator) bulges out as the top (north pole) and bottom (south pole) flatten/come together. This is what’s happening only instead of outside forces acting on the earth, it’s the centrifugal force of the earth rotating that is causing the middle of the earth to want to push out while simultaneously drawing in the poles. Causing the ellipticity. I can’t explain that any better so I hope someone can not only confirm what I’m trying to portray but also elaborate on it. | 2 |
7a1ubn | Biology | why do flies rub their front legs together? | They are cleaning themselves. Flies rely on their compound eyes, antennae and the bristles on their bodies and legs to sense the world around them. They have to keep these sense organs clean so they can fly with precision to find food and mates and avoid predators. | 2 |
cfk2pt | Biology | Why, despite all milk producing mammals did human chose cow's milk? | Multipurpose, in the same region they had cows, sheeps, goats, donkeys and horses. The most usefull are horses, donkeys and cows, cause you can get from them meat, milk and a worker. Horses were chosen to mobility and work (they produce around 11-20 litres daily, that its, give or take, what produces a meat cow), also a pregnant mare can't be used to move around. Donkeys are used to work and meat, as they produce the less milk (\~2 litres). & #x200B; Today, when you speak of a cattle breed its normal to know its purpose, ex: [Holstein cattle]( URL_0 ), at right below the pic you have the purposes, milk and dairy, though they excel at milk; [Cachena]( URL_1 ), instead, it's a triple purpose breed. | 3 |
avkrzk | Biology | - Why does heat help myalgia (muscular pain)? | Your nerves are bad at multitasking. If you add heat, they have to send a signal to the brain that there is something hot on your body. Temperature also have precendence over pain, hence a lot of your nerves will stop telling your brain about the pain since they are distracted telling it about the heat instead. | 1 |
l8szh1 | Biology | Why do some foods quickly become overwhelming? Like a quadruple chocolate cake or foods that taste very "rich". | It’s the calorie density, mostly. Our bodies are very good at knowing when they’ve eaten enough calories, so even if your stomach isn’t full (and its stretch receptors aren’t activated), there are other systems in your body saying “okay, that’s probably enough.” | 2 |
6qwz2e | Repost | How are animals able to retain such muscle mass with a restricted diet yet humans need a constant amount of protein and nutrients to maintain much less muscle? | The other factor at play in attaining and retaining muscles is myostatin. Myostatin is a protein (also called GDF-8) which inables/inhibits muscle growth depending on how much of it is present in muscle tissues. For example, Gorillas produce very little myostatin and, as such, are extraordinarily muscular without the need for extensive exercise. Humans, on the other hand, produce much more myostatin and so are less muscular and require regular strenuous exercise to attain significant muscle mass. This is due largely to our ancestors being very well adapted to running long distances. Our less muscular frame makes prolonged exertion possible as we're not burdened by a large amount of excess weight that additional muscle mass would add. A Gorilla is very quick over a short distance but it can't chase you for very long. | 7 |
cw6htn | Technology | What makes batteries chargeable and how are they charged in the first place | There are two types of regular (AA for example) batteries. Non rechargeable batteries have two chemicals that send energy from one to another through a device. Once all the energy has moved from one end to the other or been used by the device, the battery is dead and must be disposed of. Rechargeable batteries have two different chemicals. When plugged in to a battery-operated device, they work the same way as a non-rechargeable battery. But when plugged into a device with something else on it providing the energy, like your wall power outlet, the energy can be pushed backward and refill energy in the first chemical. When you try to recharge a non-rechargeable battery, the energy isn't moved back, and instead turns into heat. This makes the chemicals really hot, until they explode out of the battery and make a really dangerous mess. That's why you shouldn't try to recharge non-rechargeable batteries. | 2 |
isxojy | Other | Why are babies not afraid of the dark but children are? | Imagination and creativity don't really become sophisticated enough in the human brain until they get to be child aged. | 4 |
je5yi4 | Economics | Why are there tax returns in the US? Why do we overpay our taxes all year to get reimbursed later? | In most other countries, the government knows all of the information about how much income you made, how much interest, dividends, capital gains, etc. The government figures your taxes for you. You can log in to the taxing authority website (like the IRS) and make changes is you have charitable contributions or other changes. In the US, H & R Block and TurboTax have effectively lobbied Congress against letting the IRS do this. Basically that’s asshole companies cost the American taxpayers lots or time and money each year doing something that the IRS could do for them. For free. And why do they do this? Greed. | 11 |
8cwy85 | Other | In the US, what is the difference between State troopers, sheriffs, and city police? This is just something I’ve been wondering about recently during my daily commute. Are sheriffs local elected officials? Do state troopers have the most power? | It really depends on the jurisdiction. Most state police cover state and federal highways and areas of the state that are not covered by local police or sheriff departments, but they have jurisdiction anywhere in the state. Local police patrol a specific jurisdiction in the state such as a county, parish or incorporated city or town. Local police only have jurisdiction within their specific area (state police can also patrol these areas but usually leave it to the local police). Some Local jurisdictions use a sheriff's department instead of a police department (sheriff is a much older law enforcement term originating in Europe) with deputy sheriffs providing law enforcement for the community. In some jurisdictions, there are both sheriffs and police departments. In those jurisdictions the sheriffs most serve the court as security and serving warrants for the court. | 4 |
kj93kk | Biology | Do we think in a language? | Short answer is yes. My first language is German and I did not learn English until I was around six years old. When I first started to learn English I was thinking in German and had to translate everything into English. After a while I started to think in English as well. Now when I speak German I need to do the exact opposite. | 4 |
c8u95m | Technology | Why do cameras have different framerates for different video resolutions? The DSLR that I own shoots video at 720p 60fps but 1080p at only 30 fps? Why cant it also do 1080p60? | This is limited on the rate of how much information the camera can store/process. Let say your camera can store 65 million pixels per second. 720p is a resolution of 1280×720, or 921,600 pixels per frame. at 60 frames per second, your camera is recording the information of 55.2 million pixels per second. which is great! you camera can handle it. Now when you want to record at 1080p, that is a resolution of 1920x1080 pixels or 2,073,600 pixels per frame, so just over double the number of pixels per frame. at 60 frames per second, that would be 124million pixels per second, that is too much for your camera to handle, so we would have to cut the number of pixels to about half. To do that, you can either half the resolution down to 720p or half the framerate to 30 frames per second. | 2 |
glzcmd | Economics | Why is every country in debt with each other? Are they actually paying each other back? | Most national debt is not owed internationally from one nation to another, it is owed by the government to citizens, investors, and many parties. Governments sell bonds - they say "give us $100 now and we'll give you $102 back next year". From the government's perspective, selling this bond is essentially borrowing $100 at 2% interest per annum. For the buyer of the bond, this is essentially loaning the government $100 for a year for a 2% per annum return on investment. The reason national debt is bad is because that $2 is expensive to keep paying. If a country is continually in debt like the US, the government is constantly paying out interest to bond holders - and that's money that could have been spent on public services, healthcare, infrastructure, etc. Some countries like the US have trapped themselves under massive debt. Many countries have a balanced budget (close to zero debt, where they borrow some years and save other years). Some countries have a large sovereign wealth fund which they can dip into whenever they need money instead of borrowing. The US has trillions of dollars in national debt and there seems to be no talk of balancing the budget on the table politically from anyone as far as I can see. The result is that the government just pays billions in interest every year, instead of spending those billions on public services. **TLDR**: Governments don't go to each other and ask to borrow money. They sell bonds to investors, citizens, foreign nationals or governments - basically anyone who wants to buy the bonds for a guaranteed return on investment. They don't really owe money to each other, they owe money to a massive different pool of investors. Edit: Obviously I don't know everything about this subject, just the surface level skim I have provided. Government debt may not be inherently bad, as others have outlined below. As always it's a complex topic that an ELI5 can't cover comprehensively. | 7 |
5sba32 | Technology | How were the lights synchronized in Lady Gaga's halftime show? | I was just trying to figure out the same thing. I know the sky ones were Intel drones but I more curious about the lights everyone had on the field. It didn't seem their positions were pre determined. | 7 |
70020g | Repost | What exactly happens when a body part "falls asleep"? | You have some sort of pressure applied on an area of that body part, and have caused blood flow to slow. As it slows down, and that part of you isn't given enough oxygen to work correctly. Your nerves then begin to react, telling you to remove whatever pressure is on your arm, and bring the bloodflow back to normal. | 1 |
jso8jz | Mathematics | How do you do something for Pi seconds? How does that work? [Scenario below] What would happen if someone tried to do something for Pi seconds? I created this scenario in my head earlier today and I feel that there is definitely something I’m missing because the answer seems like it should be easy but i can’t seem to find it. Say that Person 1 (P1) Takes exactly 3 seconds to do a push-up, P2 takes exactly 3.5 seconds to do a push-up, and P3 takes Pi seconds to do a push-up. P1 would finish the push-up first, P3 second, and P2 last. This is obvious, since the numbers (3, ~3.14, 3.5) work easily that way. To an onlooker, it’s clear the order in which the push-ups were finished. But, seeing as though Pi never ends, how does P3 ever finish their push-up? In one way of thinking, isn’t it fair to say that, to a microscopic level, they never finish their push-up? The number of seconds it takes for them to finish it is so small, to some degree, they will never complete the task? But, we already know that they complete the task because Pi is between 3 and 3.5, and P1 and P2 already finished theirs, and so P3 must’ve, logically, finished theirs as well? Please don’t roast me to oblivion, I’m honestly looking for an answer that makes sense. Thank you! x | This appears to be a variation on one of [Zeno's paradox]( URL_0 ), though I'm not versed enough to fully refute that. But I'll give a try. While pi is endless, that doesn't mean it is infinite. It rests between 3.14 and 3.15, so at some point between the two, that person will have completed a pushup. If you want to be more accurate, you could say that it rests between 3.141 and 3.142, etc. This doesn't mean that it takes longer for that time to pass, just that you are being more accurate. Just because you can say that it goes infinitely deep, that doesn't mean that as time passes, it'll never reach that point. You could also say the same for 3 seconds. We know 3 seconds happens between 2.9 and 3.1, or that it happens between 2.99 and 3.01. Your example of 3 is also an infinitely long number when you become extremely precise, just that the long parts are zeros (3.000000...). | 3 |
e5dis6 | Physics | what controls the speed at which planets rotate? | Angular momentum essentially. As the sun formed, it left behind rings of dust at intervals. Those dust rings then condensed into bigger and bigger lumps which smashed into each other to eventually form planets. While there is some randomness to this process, the fact that the dust further from the sun is orbiting ~~faster~~slower (thanks 242424) means that usually planets rotate the same way (there are exceptions). On top of that, you have the influences of the moons - the spin of the planet, and of the moon, are slowed down over time as tides bleed energy from the system. If certain conditions are met, they can even become tidally locked, where the same face of the planet / moon always faces the other body. | 3 |
8pff6g | Biology | how does your body replicate the feeling of falling when your having a nightmare? | All feelings exist in the brain as patterns of neurons firing. If the brain happens to experience the same set of neurological firing, it feels the same to you. These phantom sensations can be anything from imagining your phone vibrated in your pocket to imagining that you're falling to imagining you hear your name spoken. The frequency and severity of these hallucinations (because that's what they are) is the difference between healthy and disordered brain function. | 2 |
a8v4yt | Technology | Why do many web pages seem to first load once, then disappear / realign and take another couple of seconds before they are actually done? | Hey there! I built websites for a living for about 7 years. There are a couple reasons this can happen, but the simplest explanation is that every website is made up of several different parts, and those parts can finish loading at different times. The main "parts" of a website are: * The static layout/HTML, which includes any pictures/text/layouts that are *always* on the website * The dynamic content (like blog posts, inventory on sales pages, or videos/pictures on gallery pages), which usually doesn't appear until the behavior/JS (below) is finished loading * The formatting/CSS, which takes all of the content described above and arranges it to look pretty * The behavior/JS, which allows the website to animate, load dynamic content, and perform other programmatic tasks as you interact with the site Most web browsers (Chrome, Firefox, etc.) are designed to start showing a website as soon as it has *anything* ready to show, even if there is a bunch of stuff still loading. Because of this, it is very common to see the not-fully-loaded version of a website for a second or two before everything finishes loading. When one part of a website is loaded, but the rest of the site hasn't finished loading yet, you can get some bizarre-looking results. For instance a website without CSS will often look like a boring, broken, black-and-white-and-blue page (example: [Amazon homepage with missing CSS]( URL_1 )). A lot of websites \[wisely\] don't start running any of their interactivity/animation code until the entire site has finished loading, which means a website that relies heavily on javascript might look funky before the initial startup code has been called (example: [Neopets before (bottom) and after (top) javascript loads]( URL_0 )). A lot of websites try to "hide" their partially-loaded site with "hide everything" code that runs as soon as it loads, then "show everything" code that runs once *everything* has finished loading. The problem is that sometimes, the "hide everything" code doesn't load/run until after you've already gotten a peek at some of the partially-loaded website. So on your end, you see: * The website starts to load, and you see the partially-loaded website * The "hide everything" code runs, turning the website blank momentarily * The website finishes loading while the website is hidden * The "show everything" code runs, and you're finally shown the finished website The most common solution to this problem is to use inline styling to make the page *start* invisible, and not become visible until after everything has fully loaded. The problem with this solution is that if the page never fully loads, or if the user has javascript disabled, the website never displays. It *is* possible to get around these issues with clever code and some inline styling. You've probably noticed that Google's homepage is remarkably consistent when loading across multiple devices and slow connections. But this is usually a low priority for web developers, who are mostly concerned with how the website looks and functions once fully loaded, across multiple devices. | 4 |
7edtrz | Economics | Why do companies (Google, Apple, etc.) that have billions of dollars worth of debt not pay it off when they have the money for it? | Because money makes more money over time, so if Apple has to option to pay debts slower than they actually need too, they can use the money not spent on these things to gain more interest from investments. | 16 |
bi43ig | Physics | How does an infinite universe not violate conservation of energy and imply the existence of infinite energy Wouldn't the idea of the universe being infinite be automatically invalidated by the fact that such a thing implies the existence of infinite energy? Since ZERO energy is absolutely impossible (you can only come closer and closer to zero, not reach it), an infinite universe would either imply that, at some point in the universe, the empty space's energy reaches zero (an absurdity) or that there is infinite energy - and that would be problematic in and out of itself. ELI5; why is the idea of an infinite universe becoming more and more accepted if it causes such problems then? | The energy in the universe might be infinite (because it is infinite in size), but the energy density (= energy per volume) is definitely not infinite. Also, zero energy is not impossible, you might be thinking of temperature. In which case yes, the universe cools down as it expands. | 5 |
nkdogs | Biology | why do people pass out when they get punched in the face? Obviously you can get "knocked out" but why does your body just go to sleep when you get hit in the face? | if the punch is hard enough it will cause your brain to rattle inside your skull and when your brain hits the walls of the skull it can injure itself(bruising and swelling) this will immediately knock you unconscious and it causes actual damage, congrats you just had a concussion and should probably avoid further punches in the head in the near future. | 2 |
dl2bt7 | Other | why do SWAT teams use rams but firefighters use axes if the purpose of both tools is breaking through doors? One of these tools has to be more efficient than the other, so why don’t both use the same tool? | Retired cop here, served as a SWAT commander. SWAT uses rams to punch a door open quickly. It's not always the right tool for the job, but it's the most frequently used. Jamb spreaders, hooligan tools, breaching rounds, and explosives can be used as well. The difference is that many SWAT operations are planned in advance, and we know exactly what to use. If it's a dangerous, no-knock thing, we have to make entry quickly for a safe run. There's usually a designated breacher, so he carries a heavy ram that's ditched after use. Firefighters are in a different situation, and a fire axe covers a lot of ground for them. They don't need to worry about a reactionary gap (being super-fast), so they have time to chop through a door, roof, wall, window, or whatever to enter, exit, or vent a space. The axe covers a LOT of tasks with a small weight load in addition to all the crap a firefighter is already carrying. | 14 |
hp1egk | Biology | Why is Cauliflower considered lowcarb even thought it's nutritional value shows it has more carbs than proteins or fats? | Because it is about 5% carbohydrates and about 2% dietary fibre. Since dietary fibre is a carbohydrate that your body can't digest it doesn't count towards that amount of carbohydrates. So in effect 100g of cauliflower has 3g of carbohydrates which is fairly low. If you were on ketosis you could get 1.5kg or cauliflower and still be under 50g for the day, and probably sick of cauliflower by then. | 2 |
kpe0jp | Biology | How does carbon monoxide poisoning work? Why can you die in your sleep of it and not be "alarmed" into saving yourself? Hi reddit. I was reading about [this tragedy in Bosnia where a bunch of kids partied for NYE but turned a heating generator overnight and ended up dying]( URL_0 ). Really sad story, but it had me wondering how none of them could be "alarmed" their bodies to react, in the same way that your body might choke if you can't get air and force you to seek it, etc. I would've thought something might happen to kick in this response and there'd have been some way to get to safety. So...why not? | Because carbon monoxide is not a common problem in nature. So we never evolved mechanisms for recognizing when it is building up. When you breathe carbon monoxide, it doesn't choke you, it binds to your red blood cells just like O2 does, and kills you by not letting any oxygen get into your body. | 2 |
9i1hts | Culture | Why do priests ask the people if they want to object at weddings? Is this an old tradition? Is there a story behind this? | It is an old tradition. It is also basically meaningless these days which is why there are a lot of people who leave it out. Basically, there have always been legal (or religious) reasons for why two people couldn't get married. Think of them being related or one of them already being married. Nowadays, all of that is pretty easy to check beforehand thanks to computer systems. Back in the day though, there were no easy ways to check this, so they depended on members of the public. Essentially, this line was meant to ask if any member of the public knew of a legal/religious reason why these people shouldn't be married. So it wasn't asking for someone to go 'no, Sandra, don't do it, I still love you'. Rather, it was so someone could go 'the groom already has a wife in another town, so this marriage is illegal'. | 3 |
f81ofe | Engineering | How can satellite dishes receive high resolution media with little lag and no buffering time but this same technology can't be used to send internet to rural areas with massive lag and data restrictions? | It's the difference between broadcasting and internet type communication. With a broadcast a satellite is just beaming out a high power signal, and people are receiving it on the ground. There might be lag on it, how would you know? All you're seeing is the images and sound as they arrive. With Internet communication there has to be a two-way communication going on. That's where it becomes more difficult, because the lag between you sending the signal up, it getting down to where it's going, and the response coming back is far more noticeable. | 6 |
63eetq | Technology | What is a DDos attack and why would anyon want to do it? | basically it's like asking a question. as a person you can only really listen to and answer 1 questions at a time. if we then assume a person with a question will only wait a set amount of time before they get fed up and walk away, let's say 1 minute. then we can start to see where problems arise. image it takes 5 seconds to to listen and answer a yes/no question. this means you can answer 12 people in a minute as a maximum. usually only 1 or 2 people will turn up to ask, so this is not a problem. A ddos is when somebody sends 100 or 1000 people at the same time to ask you a pointless question. becasue of this those 1 or 2 with legitimate questions get lost in the queue and after a minute, they walk away. Similarly a network or server can only manage so many conversations with other computers. so when a ddos sends millions of requests to a single point, they are overloaded and other people requests timeout. The solutions to this are things like having someone vet the questions first. if you know that person is a timewaster, he doesn't get allowed in to ask a question (this would be your firewall). Or you hire additional people to answer questions and try to split the load. (network load balancing). | 2 |
6h2q1c | Repost | what is a terraflop? What advantages does this bring to me? How does this correlate the new Xbox one x? | FLOPS is a measure for FLoating point Operations Per Second. This measure indicates the speed at which a computer processor can chug through calculations. "Tera-" is a prefix meaning "1000 times Giga-". You might have heard of Gigabytes or Gigahertz? Those are just the "giga" ordinal for bytes and hertz. "Giga-" means "1000 times Mega-", "Mega-" means "1000 times Kilo-", and "Kilo-" means "1000 of something". So: 1 Teraflops = 1000 Gigaflops = 1,000,000 Megaflops = 1,000,000,000 Kiloflops = **1,000,000,000,000 flops**. So a 1 Teraflop processor can calculate 1 trillion operations per second. For comparison, there exist supercomputers that run upwards of 30 *Peta*flops, where 1 Peta = 1000 Tera. Quite the head-spinner, that one. :) --- **How does that benefit you with the Xbox One X?** Supposedly, the more FLOPs, the better. The Xbox One X will be coming out with a GPU that processes at 6 teraflops, or "TFLOPS", meaning it comes close to the performance of an nVidia GTX 1070 ([which operates at 6.5 TFLOPS]( URL_0 )). That should produce some decent high-res visuals at a good framerate, if the console is all it's chalked up to be. Edit: silly me, I forgot Giga! And I call myself a techie. :( | 2 |
k3okxw | Chemistry | Why does coffee enhance chocolate flavor? Kinda had a similar question before, but there's another flavor combo I remember is supposed to work very well: coffee and chocolate. Just a little bit of say, instant coffee is recommended to be added to say, chocolate cakes, or fudge to enhance the chocolate flavor, according to recipes I've found online, as well as from people I know in real life. How does this combination work? Is it because of similar flavor compounds in cocoa and coffee? | I feel like this is a question for Alton Brown. I loved his cooking show because he would tell the viewers the reason behind all the cooking techniques and flavor profiles. I don't know the answer, but I have also heard of it. Most say you can't even taste the coffee, which is the confusing part to me. | 1 |
b57i6r | Biology | Why is cancer so deadly? I’m having a really hard time understanding why it’s so much more deadly than something like AIDS. Like AIDS literally attacks your bodies immune system until it’s basically impossible to fight off infections. They can literally die from things like a cold. Though cancer from my understanding causes problems by taking nutrients from an organ, blocking passageways for things like arteries and the GI tract and causing the brain to push up against the skull. This doesn’t seem that deadly yet it kills so many people every year. I’m genuinely confused. | Cancer is uncontrolled cell growth. Most cells will divide until they are no longer needed, and then they will stop Cancerous cells are damaged, and so they have no stop function. One cell becomes 2. 2 becomes 4. It continues exponentially. These cells continue using up resources and taking up space of healthy cells. And depending on what type of cell is damaged and continues to grow, they can move to different parts of the body and start taking over other areas. This is why it is dangerous. They are the Energizer Bunny of the cellular universe | 2 |
dm5rxh | Biology | Why is it that one can have both depression and anxiety, when they seem to be opposite illnesses? | From personal experiance, the 2 actually stack on top of each other. I started out having anxiety issues, and having anxiety lead me to not want to go anywhere cause of my panic attacks, which started my depression from my isolation from people or events. Then my depression added to my anxiety cause I thought none of my friends cared or would understand why I was feeling like that. It sucks. I dont have a whole psychological explanation, but that's what happened to me. Edit: spelling | 5 |
5yry50 | Biology | Why do you get better for a few days after receiving a fatal dose of radiation? An excerpt from this excellent collection of photos: URL_0 "Once exposed, nausea and vomiting will begin almost immediately, and within a short space of time your tongue and eyes will swell, followed by the rest of your body. You’ll feel weakened, as if the strength has been drained from you. If you’ve received a high dose of direct exposure - as in this scenario - your skin will blanche dark red within moments, a phenomenon often called nuclear sunburn. An hour or two after exposure, you’ll gain a pounding headache, a fever and diarrhoea, after which you’ll go into shock and pass out. After this initial bout of symptoms, **there’s often a latent period during which you’ll start to feel like you’re recovering**. The nausea will recede, along with some swelling, though other symptoms will remain. This latent period varies in duration from case to case, and of course it depends on the dose, but it can last a few days. It’s cruel because it gives you hope, only to then get much, much worse. The vomiting and diarrhoea will return, along with delirium. An unstoppable, excruciating pain seethes through your body, from the skin down to your bones, and you’ll bleed from your nose, mouth and rectum. Your hair will fall out; your skin will tear easily, crack and blister, and then slowly turn black." | Radiation damage is basically completely random: it goes through your body and when it hits a molecule, it breaks it into pieces. If that molecule was something not too important (e.g. part of a cell's outer hull) and the pieces are by themselves not dangerous, then nothing much happens, the cell just cleans away the the pieces. If the molecule was important for the functioning of the cell, or the pieces are harmful, then the cell is damaged and has to repair itself (which means it can't work properly for a while). If it is damaged too badly, it dies and has to be replaced. If too many cells are damaged, you die very quickly, but if it's not too many (but more than a few) you just get sick, but you recover - the "latent period". However, the radiation also damages the DNA (a very large molecule), the "blueprint" which cells need to reproduce and be replaced (also to create stuff for their daily work, but I'll skip over that aspect to keep things simple). So if there has been to much damage to DNA, then cell reproduction will fail sooner or later or the new cells won't work properly. Your body cannot replace cells and instead produces garbage. This happens first with cells that are replaced quickly, such as the ones lining your digestive tract and the ones that let your hair grow. Eventually you die. This is delayed because even the cells that are replaced quickly live for a few days, so it takes at least that long for the damaged DNA to show the full effect. | 18 |