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Why does water, even at room temperature, always feel colder? | Your skin doesn't actually feel temperatures, but the amount of heat that is leaving your body. Our skin temperature is generally higher than room temperature. Because water transfers heat away from our skin, it feels cool.Water is a better conductor of heat than air. In fact most things in your "room" will be at room ... |
How does a truth serum work? | Short answer is they don't. There is no truth serum available. Some of the things that were sometimes used are things that make you less inhibited or act stupid. Basically getting the person high, jittery or drunk. It's seldom if ever worked, the prisoners would continue to spout nonsense with no real way of making sur... |
If the big bang started with everything in one dense point, why does the observable universe imply there is more beyond what lightspeed has allowed us to see? | There's a common misconception that the universe can only expand at under the speed of light. That's false. Objects, things with mass, are limited in the speed of expansion. However, the space between objects is not limited by this. |
Why does everyone hate the sound of their own recorded voice? | It's something about your voice sounds different to you because it echoes around in your head a little and the recorded version is actually what you sound like, but you're not used to it. |
Why and how would a 1100 decibel sound make a black hole larger than the observable universe? | A decibel is a measurement of sound pressure, and it's what's called a logarithmic scale. So to increase by 3db you need to double the power. Rising like that, you can imagine by the time you've done that over a **thousand** times, the result is going to be pretty astronomically enormous. It's like the old grain of ric... |
How do we know what our Milky Way galaxy looks like? | We don't actually know. Any pictures you see of the spiral shape of the milky way galaxy are either artists representations or pictures of other galaxies that we know to be the same shape. We know roughly what shape our galaxy is because we can see how far away all the other stars in our galaxy are and sort of compute ... |
Why does squinting improve vision? | You are usually squinting because an image isn't at the right focal distance. When you squint, muscle pressure slightly reshapes the surface of your eyes which changes how it focuses light and may make the view clearer. If you have glasses this is especially obvious: You can take off your lenses and gently pull backwar... |
How does light/photon speed back up to c after it exits a medium like glass? | There are a few ways to think about this problem. The first is to start with the photon entering the medium on one side, then it travels through the glass and exits on the other side. Based on conservation of momentum, you know that the photon speed must be the same before and after the glass. There is another way to c... |
Why does the northern hemisphere get covered in so much more ice during its winter than the southern hemisphere? | There's more physical land in the northern hemisphere than in the southern. The equator passes through southeast Asia, slightly below mid-Africa, and the upper portion of South America. If you were to fold that .gif over at the equator, you'll find that most of the regions that get covered with snow in the northern hem... |
with the massive amount of gravity that the Suns has, why do the planets orbit the sun instead of being drawn into it? | You tie a piece of rope around a tennis ball and spin it over your head like a lasso. The sun's gravity is the rope keeping the ball from shooting away from you. The gravity is strong enough to hold earth in orbit but not so strong that it pulls it to crash into the sun. |
What is "The Internet of Things" | It's where you connect a bunch of things that you don't typically think of as computers to the Internet, allowing them to work together. For example, your thermostat could be connected to your calendar so it knows when you're going to be away for a while and it will turn down the heat when you're not home to save energ... |
What am I actually doing to blur my vision on command? | Your eyes focus on different things by deforming a lens inside your eyeballs. When you do it consciously you just override your brain's natural reaction and cause the muscles responsible to deform the lens so that it focuses on something farther away, causing the object you're looking at to blur. |
Why do many analog clocks with Roman numerals use "IIII" instead of "IV"? | History. The king of France had a preference, , or made a mistake about the Roman numeral 4, , and asked a clock maker to fix/change the IV to IIII on a clock that had been made for him. You don't want to go against the wishes of the king so it soon became customary to use IIII. |
How does this glass not break? | It's a plastic composite (glass laminated with thick plastic. Also he's using a blunt hammer. A spike or a pick would do more damage. |
How did Germany defeat France so quickly in WWII? | Basically, France couldn't legally extend their defenses into Belgium but also couldn't build defenses on the Franco-Belgian border because it would look to Belgium like France was leaving it high and dry against Germany. Germany, with the use of fancy new mechanized tools such as trucks, was able to move across Belgiu... |
If heat and temperature are just the result of molecules physically moving how does salt lower the freezing point of water? | Imagine you have four marbles and a tiny box just big enough to fit them in. When the marbles are outside the box, they just roll around. When they're packed together in the box, they can't move at all, like they're one solid. Take out the marbles, put a screw in there, and try to put the marbles back in. Even though t... |
Is it possible that gravity works completely different in other part of the universe that may contradict our own model of it? | I think its obscenely unlikely. We're able to map the universe very very far away, and it seems like gravity more or less works consistently. Now, what is possible is that if there are OTHER universes or dimensions, that there might be different laws of physics that apply to them |
what exactly is Cherenkov radiation ? | Light travels at speed c only in vacuum. In water it travels at 0.75 c. However, during a nuclear reaction, electrons can be accelerated greater than light in water. When the electron travels through the water, it locally disrupts the electromagnetic field of the water. If the electron travels faster than light through... |
Why does staring at light make you sneeze? | The nerves from your nose and your eyes pass really close to each other on their way to the brain. When looking at something really bright the strong signal is carried over from your eyes' nerves to the nerves from your nose as an electrical disturbance. Your brain interprets the disturbance as a need to sneeze. |
How do spiders not get stuck on their own webs? | They make some non-sticky strands and walk on those. If they accidentally step on a sticky one they have seven legs to pull the one leg free. edit: people seem to doubt this. [Here's an attenborough link showing the process by which most webs are made]. |
Why don't alcohol bottles just display alcohol content in a percentage rather than multiplying by 2 and putting 'proof'? | They don't do this in the US? In canada it's always labelled as a percent. Beers around 5, wine at 11-15.. Etc |
Why do mosquitoes bite some more than others? | Mosquitoes are attracted to sweat, so if you're not taking as frequent showers that could be a problem. Some other reasons too: _URL_0_ |
Why weren't the Native Americans as technologically advanced as the Europeans? | The natives of North America never discovered how ridiculously rich the land they lived on was with various ores. Because they never mastered the use of ores and metals in producing various items, they couldn't advance in the same way Eurasian people could. The skill of metal forging was an essential stepping stone to ... |
What is the difference between Christianity and Catholicism? | Catholicism is a sect of Christianity that has beliefs slightly different to other sects Think of it like states in America: they're all part of the same country and all have largely the same rules, but each state has some different laws than others would. |
Since the human eye only has 3 types of cones in the eye, (red, green, and blue), why do some TV's have RGBY pixels, instead of RGB? | This is basically why_URL_0_ from:_URL_1_ IIRC When trying to reproduce colors on a screen the R, G and B cells can be any particular shade of Red, Green and Blue respectively. Now if you draw a triangle connecting those three chosen shades on the diagram posted above you get the range of color that your screen can dis... |
The difference between senate and house of representatives | The House is a proportional system where members are allocated to the states based on the state's population. It's closer to the people and members are said to represent the interests of their individual districts. The Senate is an equal system where each state, regardless of size, has two members. It's members represe... |
How is it that, according to special relativity, light always appears to move at the same speed, regardless of the speed of the observer? | There's no why, it's something you assume. It's sort of like asking why 1+1=2. You can't reason about it, it just is. Once you assume that light always moves at a constant speed, you work out the math and you get modern physics. So you could ask, why do we assume that the speed of light is constant? The answer is, once... |
How is it that we can see the same stars at night all year around? Shouldn't some stars be obscured due to being on the other side of the sun? | This is totally a thing, except those stars aren't so much obscured by the Sun as they are washed out; that's what we call daytime. |
In days of American slavery, were Africans the only people who were forced into slavery, or were there other races as well? Why were some groups forced into slavery while others immune? | Columbus started off by enslaving Carribs in the islands; the Spanish continued the practice and virtually exterminated them; then went on to enslave the Aztec and Inca people they conquered, silver mines being an especially lethal place where they were forced to work. The early British settlers used 'indentured servan... |
Escape velocity. Can't you escape earth's gravity at any speed as long as you had the power? | Escape velocity depends on the distance from the body you're escaping from. If you maintain a constant speed away from Earth using thrust to balance against the force of gravity, eventually you'll be far enough away that your speed is above the escape velocity. At that point, you can shut off your engine and you'll nev... |
Being that we're able to find planets a habitable zone far throughout our galaxy, how is it that we've yet to find all the planets in our own solar system? | We find exoplanets by watching their stars wobble and change brightness. Then it's a matter of math to determine distance between star and planet, with some guessing too. If we estimate the size of the star wrong, we'll get the size/orbit of its planets wrong too. Planet x however. Is very far outside the habitable zon... |
Why are there more right handed people than left handed people? | Although this doesn't explain it entirely, it does increase the ratio of right handed to left handed:Left handed people used to have it literally beat out of them in many schools , and would be forced to write with their right hands. To compound that, children learn through observation, so although I write left handed,... |
what would happen if all the other stars in the universe disapeered? Do they have any effect on the Earth? | As long as our star exists, the effect would be largely negligible as far as life on Earth is considered. If we were ejected from the galaxy *with* the sun, life would consider essentially as before. In short, no, the rest of the universe doesn't have much effect upon us. That being said, if our star is the last star, ... |
Why do humans smell with with a long slow sniff, while most animals rapidly sniff several times. | I don't think all humans do, it's perhaps a learned behavior. I have a keen sense of smell and do what I'd describe as many micro sniffs, similar to a dog, when I catch the scent of something I can't put my finger on. |
If I sleep for 6 hours during the night and then take a 2 hour nap, am I getting the same benefits of sleeping for 8 hours straight? | Looking up research is a bit inconclusive on this. There are some advocates for what's called biphasic sleeping . Although the nap isn't usually 2 hours but rather just enough for a full sleep cycle. Of course, this being reddit, there's a whole sub on people's experience with various polyphasic sleeping: /r/polyphasic... |
After serving as a Juror, can you talk about all aspects of the trial after the verdict and conviction has taken place? | Yes you can. You can go in detail as you want. I believe you're merely prohibited from making money off it/selling your story to the media for 90 days. Did they not give you instructions? |
Tattoos - how do they work? | The ink is injected into the dermis, beneath your outer skin, where it is sandwiches between cells. It's non-degradable so hangs out there forever. |
If light cannot escape a black hole, doesn't it mean light is accelerated to faster than the speed of light inside the black hole? | I have a follow-up question that hadn't occurred to me until I'd thought about how to explain this. Light moves in a straight line through space. Any curvature in its path is caused by the curvature of space time itself I'm having trouble imagining the geometry of spacetime that would mean that a locally straight line ... |
Why is the Earth's core so hot? | Two reasons: 1) It's got a lot of radioactive metal in it and 2) all of the energy that was carried by the dust/debris that originally fell together to form earth didn't go anywhere, some ended up as the spin of the planet, and some ended up as heat. |
How do rockets move shuttles through space? It's a vacuum. What is it "pushing" against? | Itself basically. Every action has an equal an opposite reaction. You have hot rocket exhaust going one way, and it's imparting an equal and opposite force the other way, where the rocket is.This is a very common misunderstanding. Rocket engines do not push against anything. They do not push the rocket "off the air". T... |
How does a stock market crash? | Stocks represent ownership in a company with real-world value. That is what makes them valuable. However, in cases such as the '29 crash, investors were trading stocks far above their real-world value. Eventually, investors take notice and try to pull out what money they can out of the market. With enough investors doi... |
If you pit ice in a cup with water and it melts the water level stays the same...how come the icebergs melting is causing water levels to rise? | It's not the icebergs that are the problem. It's the polar ice caps and gigantic glaciers. They SHOULD be remaining frozen and solid, but with rising temperatures they're breaking off and melting much more rapidly than they should. |
Why to planets "circle" the sun? | Go back to the beginning of the solar system. Some of the bigger clumps of matter get pulled together, which makes their combined gravity stronger, pulling bigger lumps together. Lumps that are farther away will end up moving towards the central big ball, but what if they miss? They keep going until gravity pulls them ... |
When you have a cold, why does your nose clear up while you're sleeping, and immediately start running again when you wake up? | Mine clogs totally shut when I'm sleeping then loosens right up in the shower for a really satisfying nose blow after my shower. |
since we've discovered gravitational waves, does that mean that gravity has a speed? | Gravity propagates at the speed of light. While if can move out of a black hole while light cannot escape, it isn't because it's faster, it's because gravity isn't affected by the gravity of the black hole. Even light isn't really slowed by a black hole, but rather gravity bends space time so light curves around it, li... |
Why can't we tickle ourselves | If you think about it most people are ticklish on places where you have main arteries and soft unprotected parts like the belly. Parts of the body that you really should learn how to defend. The reaction to tickling is laughter which isn't off-putting for someone playing with you and your reaction is instinctively to p... |
what is the difference between ' and `? | It's a [grave accent,] a diacritical mark used across the globe. In English, it's often used in song lyrics and poetry to shorten words to fit rhythm/meter. |
if the earth stopped spinning, would we "feel" the effect of earth's gravity more? | We'd feel it alright as we slam into nearby objects at up to 1670 km/hr. Just because the Earth stops spinning doesn't mean we also stop! I remember reading about a game of Dungeons and Dragons with a real arsehole player who insisted on finding a specific item, straight up ignoring the DM. The DM just allowed it to ke... |
Why do we have eyebrows? What purpose do they serve? | They keep dust and sweat out of your eyes and aid in body language. That's pretty much it. Nothing too fancy, but more important than you might think.in addition to the other answers, there is also the matter of injury If the head gets cut or bumped it is likely to be on the brow ridge. Having hair there both helps to ... |
Why do we still do daylight savings time? | Even moreso than its usefulness is mankind's unwillingness to change from common sense. There are many arguments why DST should be used/abandoned but we continue to use it to reckless abandon because we cant make up our minds collectively on wether it will be good for making money. [/rant] So essentially, aside from th... |
Why, if the moon is rotating, do we only ever see the same side of it? | Pretend you are the gazelle that the lioness wants to eat. It walks around you, but never takes its eyes off you. No matter how or when you look at the lioness you always see her face. Now pretend you are the photographer recording the imminent death of a gazelle by a lioness. You see the lioness circling the gazelle, ... |
People can't hear their own voice the same way others hear it. So, how is anyone able to do good and accurate impressions of someone else? | Impressionists don't just talk to themselves and hope it sounds right. They constantly record themselves and listen, compare directly to the recordings of the person they are impersonating. They have voice trainers that work with them as well. |
Why do birds heads Bob when they walk? | They are listening to the music of the world and dancing to their own tiny bird beat. Seriously, though, it's for the same reason that our arms swing when we walk. It helps us keep balance. Not only that but birds move their heads more than their eyes -- as opposed to humans, who move our eyes more than our heads. |
If humans are mostly made of water (which is Hydrogen and Oxygen), why are we known as Carbon-based life forms? | Carbon is responsible for the complex molecules that make us people. Yes, we contain water but if you took out all the water, you would still look like a person . If you took all the carbon based molecules out of us we'd look more like a pile of wet goop. |
Why does the Earth rotate on its axis, but the moon doesn't? | The moon does rotate on it's axis. However the moon is [tidal locked], so the same side always faces the earth and it rotates exactly once during each revolution of the earth.Actually it does, and while others have mentioned that it is tidally locked, it is not rigidly locked. If someone were to record the moon in a lu... |
Dark matter is constantly expanding faster and faster, what happens when it hits light speed? | The answer is the end of the universe as we know it. This scenario is called [The Big Rip]. The universe becomes a series of fundamental particles that can never interact with one another ever again. Good news is there's not a complete consensus on if this will happen, or how long it will take before it happens if it h... |
How do we know the Andromeda Galaxy is roughly 2.57 million light years away? I understand that is how long it takes light to reach us, but how do we measure this? | To put it in an ELI5 scope, we know how light dims and dissipates the further you are from the source. We then look for a star in the galaxy which we can accurately estimate the brightness of at the source, look at how bright it appears to us, and then use this data to determine how far away the star is. To use an anal... |
If a musical note is a certain frequency. Then Why does the same note sound different on different instruments? | It's the shape of the wave. A pure tone, typical of a flute, is a sine wave. Other instruments have waves of other shapes. This is the time-based way of thinking about it, since you're graphing the sound waves against time. Alternatively you can think of it in terms of frequencies. Every note is made up of sine waves. ... |
What is the observable universe? How can we be certain of the age of the universe if there may be something beyond it? | To add to the top answer, with the current rate of expansion, the maximum size of the observable universe has been calculated to be about 46.5 billion light years. If an object is further away from us than that, we'll never see it, ever. The distance between us and the object is increasing at a rate faster than the spe... |
If gravity keeps the moon in orbit, what stops it from spiraling closer towards earth and eventually crashing in to it? | The moon is falling toward the Earth. However, It's moving fast enough on a path perpendicular to the line defined by it and the Earth that it continuously misses. |
Atomic Explosions. How can one atom release so much energy? | They don't. It's the leftovers from one atom's reaction that is so powerful. An example is firing a neutron into an unstable nucleus. That one atom splits, and releases two neutrons, which hits two other nuclei, and on and on. This cascade creates the energy needed to boil water or level a city. Also, E=mc^2.This is li... |
What is the faint ringing noise we hear in a silent room? | In a silent room, it's just tge blood tushing through your ears - you can hear this more clearly by putting a seashell to your ear. Thats blood, not the ocean ;) If it persists beyond silent environments, and you find yourself trying to drown it out with other sounds, it's tinnitus. It sucks.If you have any electronic ... |
The difference between England, Great Britain and the United Kingdom | There is a great video by CGP Grey one of his earlier works. But if [this video] can't explain it to you, then nothing can. |
How do we know the Mariana Trench is the deepest part of the ocean when supposedly only 5% of the ocean has been explored? | Just because it hasn't been explored doesn't mean it hasn't had a cursory mapping. There's no reason to expect a sudden amazingly deep spot in the middle of areas where geologically you'd not be even slightly likely to find one. So - efforts at mapping have been concentrated on areas we already know are very deep, with... |
Why does the axis of the earth have a bigger role in its weather than the distance from the sun? | Because the earth's orbit is practically circular, while the axis angle can change seasonal daylight times by +/- 12 hours. Daylight hours control how much energy is reaching a particular latitude, and these vary over the same timescale as variations in the orbit do. Earth's orbital distance from the sun varies between... |
What determines whether your belly button is an innie or an outie? | Does race play a part in it? I'm asking because I noticed a lot of my black friends had outies when we were growing up but I noticed that a lot of my white friends didn't. Btw just in case this sparks anything racist, I'm married to a black woman. |
if matter cannot be created or destroyed, then how was matter created? | then what created THAT?" for eternity. We assume the "default" state of existence is "nothing" but that is not the case. |
If a planet or planets have been found 40 light years away, how do we know they are habitable? | At this point we can't know for sure if they're habitable or not, but we can determine if they're *likely* to be habitable or not. For one, based on the size and type of star, we can approximate the goldilocks zone and see if the planet orbits in that zone. We can also use spectroscopy to determine the constituent elem... |
How we can see stars and galaxies literally billions of light years away but are just discovering another planet in our solar system? | I would guess the reason is because the light from stars is more obvious as opposed to a planet that doesn't generate light itself and we have to rely on light bouncing off of it from the sun and that can be tricky if it's really far away and we can either in the wrong position angle wise or we might assume it is anoth... |
How low would gravity need to be for a human to survive falling at its terminal velocity? | This sort of thing gets tricky because as gravity decreases, the density of the atmosphere decreases too. With a less dense atmosphere, terminal velocity increases, which makes falls more dangerous, and I have to admit that I'm not sure where the sweet spot between gravity/air density is. |
Why is CGI so expensive? | It's not the technology as much as it is having to pay for the trained professionals using it. CGI artists are expensive to hire due to the extensive training they have to go through. A film that has intensive CGI may include dozens of technicians, each of which needs to be paid. And paying less means you get lesser qu... |
Why does water stop boiling the instant I remove it from heat? Isn't the water basically the same temperature? | Okay, so I think I can say what these guys said but maybe a little more suited to a 5 year old. Liquid water can not get hotter than boiling. Any additional heat being applied is immediately lost thru the boiling process ,which actually cools the water. That why turning up the heat only makes water boil faster. When yo... |
What is the difference between petrol and diesel? | Diesel is oily. It lubricates the engine and doesn't evaporate easily. It also isn't likely to explode from sparks. It explodes in the engine though when compressed under immense pressure. There are no spark plugs in the engine. Gas actually washes away oil inside the engine . It vaporizes very quickly and the vapors a... |
How does conditioner work? | Shampoo works by stripping all oils and all dirt trapped in those oil from your hair. Leaving it squeaky clean. Problem is..hair isn't meant to be oilless. Conditioner puts oil back into hair. You could do the same by rubbing olive oil in yer hair |
How fast is our solar system moving away from the big bang or are we sitting here and the universe is expanding? | We're not moving away from the big bang, it isn't a single point as you perceive it but we are moving relative to the galactic center and the local super group and so on.Both. Everything is expanding away from everything else. Imagine glueing objects to the surface of a deflated balloon. Now blow up the balloon. Everyt... |
Why is space cold? How does the heat of our body transfer out into space of there are no particles to absorb it? | Heat doesn't need to radiate through a medium. It can radiate through empty space as electromagnetic radiation . In this way, it's different from something like sound, which requires a physical medium to pass through. Sidenote: This is how a microwave oven works. Microwaves are electromagnetic waves that carry heat to ... |
How do we know that gravity curves spacetime and is not a force? | U/robusetceleritus covered it pretty well in the link. The way I've always explained it is as follows: Gravity is classically seen as a force of attracting masses. That means, Gravity operates on massive objects. We have also noted that light bends around supermassive objects. Light has no mass; it can't mass. So the b... |
Why didn't the allies simply bomb the beaches at Normandy, and then land troops to the wreckage? | They did, with mixed results. Hindsight, yes, more bombing could have had better results, yet poor flying weather & time lines set up for the massive amphibious troop invasion didn't work out that way. A good article _URL_3_ And a descent enough one from Wiki-P _URL_2_ . This article speaks alot of the bombing of towns... |
Why do humans need to learn how to swim while many other mammals seem to instinctively know how? | We do know how to swim, it's just that basic instinctive way is not very efficient, compared to the swimming styles we developed by Well Being smart and knowing stuff like physics. |
Could there be another universe made by a big bang a long way away from our universe? | Yes, but we could never know about it and it would be scientifically untestable so it would always remain a hypothesis rather than a theory. In fact, what you describe is the concept at the forefront of theoretical cosmology right now - Membrane or 'M' theory . M theory is an expansion and merging of several string the... |
Why does hot water taste so different to cold water? | This may just be an old wives tale, but I was taught as a child that cold water tastes better as a defense mechanism. In nature, water that is constantly flowing will tend to be cleaner, and also colder. Water that sits stagnant gets warm, but is also a breading ground for all kinds of bacteria and other bad shit. Or b... |
How do we measure the distance between us and objects in space e.g. planets, stars and galaxies. | All scientific measurements work the same way. You start with tools that have been proven correct to the point that disputing measurements with them is absurd. Then you use newer better tools to get measurements of things you already measured with your trusted tools. If you get the same answer you can trust the new too... |
Why does salt make ice so much colder | Pure water has a freezing point/melting point of 32 F or 0 C. However, there is also a property called 'Latent Heat of Fusion' which describes the amount of energy needed to turn a solid into a liquid without the temperature changing. When you dissolve something like salt in water, it pushes the freezing point quite a ... |
Why does air get less transparent the farther the distance, but the same effect does not happen when looking at Earth from space? | The majority^1 of water vapor, dust, aerosols, etc. are located within the lowest 9-12km deep layer of the atmosphere . These particles are what scatter light back to our eyes and obstruct our vision, since we now see these particles instead of looking through the mostly^2 transparent dry air . When looking down from s... |
Why does water put out fire if... | I'm not a firefighter, I'm a chemist, but I'd argue that it's because water has a really high energy capacity. Water has this incredible capacity to absorb energy, and since fire is chalk full of energy, I'd say that the water does a good job of absorbing and displacing the excess energy generated in a fire. Though wat... |
Why are different races still the same species of human? | Because the differences between differences races are very minute and all humans of all different races can breed together. While it is not always true, the rough rule of thumb is two members of different populations cannot breed and produce fertile offspring, those populations are different species. |
how do scientists know the mass of the obervable universe? | It's a large estimation. Just like a scientist can try to estimate the number of grains of sand on a beach, or the number of trees in a forest, they can try to estimate the number of suns and planets in the universe. They won't be exactly right, but with careful observation and reasonable assumptions, they can usually ... |
Why did Japan side with Germany in WW2? | The alliance was a practical one. Germany had no interest taking over the Pacific, so it was no threat to Japan. And Japan wanted to takeover the Pacific territories of Germany's enemies. The Nazis could easily make an exception to their ideology for the Japanese and vice-versa, since the Japanese also had a type of ra... |
How do we relate time to the age of certain planets and the entire universe when the speed of "time" varies based on gravity? | I'm not quite sure about your question but ill try First, time dialation is relative to the observer and if you you are observing from the same perspective all change is the same everywhere so for you there is no net change . Second, there is the thing about solar years in the sense of the time it takes for a planet fo... |
If the Universe is 13.8 B years old (Roughly) how can we see 46B light years away? | OK, so a lot of the answers below cover the main point - > that one of the main reasons you can see objects so far away is that the universe is expanding, and has been since the big bang. Thus when the light was emitted, the object was a whole lot closer. What is also interesting, and plays a huge part in this is that ... |
Why do we forget our dreams? | To start off, I will say that we don't really know. One explanation is simply that humans easily forget non-essential things. We tend to only remember important stuff or things that we think about often. You don't usually remember things while your mind was just wandering or what you were thinking about last week while... |
How does a bank work? | I hold onto your apples for you, since you don't want to keep them at home. I also hold onto apples for Joey, and for Stevie. Since I've got lots of apples that people don't need, I let Jamie borrow some of your apples, and some of Joey's apples and some of Stevie's apples, but I make Jamie promise to give me back all ... |
If the age of the universe is 13.8 billion years old, why is the observable universe 92 billion light years in diameter? | The current understanding is that in the first few moments of the universe, like the first few Planck seconds of it, it was expanding at much, much more than the speed of light. It continued to do so for a while, as the laws of physics hadn't yet come into play. They didn't come into play until after things started to ... |
If microwaves work by heating water molecules, how do they heat things without water molecules, like plates? | Microwaves don't just 'heat' water molecules but all molecules that are polarized. Microwave is an electromagnetic wave and when it passes trough your food, its phase changes rapidly and this affects everything with a charge in your microwave oven. These polarized molecules have a certain amount of charge so they start... |
if the observable universe is so small, how can we tell or have any idea how big the universe is outside of what we can see? | We can see all the way to the creation of the universe - the cosmic microwave background is us literally looking at the opaque plasma fire at the start of everything - well 380k years after that start of everything, but that's basically the same as zero on a cosmic stage. That plasma was about 4000K when it suddenly be... |
How would you see an object traveling at (or close to) the speed of light? | I read most of the comments here and I think the big thing that is missing in the explanations is that time is not what's changing relative to objects that move at speeds close to the speed of light. Space around an object is changing relative to the object that is moving with high speeds. When you move at velocities c... |
To put this simply, why cant life exist on other planets in different conditions? | Conditions were right for life **LIKE US**. Other places might have conditions favorable to forms of life that are very different from us. Of course, then you get into the question of what, exactly, is life? And almost every definition you can think of either excluded some things we think of as alive, or includes thing... |
If a brain transplant was successful, wouldn't you be saving the donor and not the recipient, because you are literally your brain? | Say a man has an RV, that he lives in and spends all of his time in. This RV is now broken beyond repair. With the help of some friends they find him a new RV to live in. Now the reason the man's friends helped him find a new home wasn't because the home needed saving, but the man.It is more likely that our brains do n... |
Is there any proof that we can't go faster than light? I mean we couldn't have the technology to do it, but theoretically why is it so impossible to ever do? | You live in a 4 dimensional universe. Three dimensions are distance and one is time . The speed of light is the ratio of the distance in the temporal one, the one we call time, to the distance in the spacial ones, which we call distance. Every object exists as a unit velocity segment in this 4-space. Since a 4-space is... |
can people survive hitting the water at terminal velocity? At what height to humans reach terminal velocity? | Terminal velocity for a human falling in a face down position is about 54m/s . In a head-down or upright position, it can be much faster. The exact figure will depend on the jumpers weight, body shape, and the clothes they're wearing. Assuming quadratic drag and a terminal velocity of 54m/s, the following table is obta... |
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