Like how can time move slightly faster when i’m somewhere else? Also how, like in interstellar, a day on our planet was like 1,4 seconds on that one planet? I can’t seem to wrap my head around the concept of that…
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Immagine an extreme and impossible example: you, looking at an stationary clock then instantly accelerating to the speed of light. What do you think you would see? Well, the clock marking the time at the moment you started moving, stopped, for as long as you’re traveling at that speed . Now dial it down a notch, and instead of it being stopped it just moves slowly…
Disclaimer: I’m no physicist or expert but this thought experiment has helped me shallowly
understand dime dialation.
It works because that is how nature works. Concentrations of mass and energy (in this universe) affect their surroundings by altering time and space.
There is no “explanation” other than observation that time and space is “distorted” by strong gravity and motion. The one concept to get around is that there is no such thing as “universal” or absolute time. What takes 1 second for you might be more or less than 1 second to someone else – there is no “correct” measure of time – it is observer dependent.
Well the reason why is “because it is”, that’s simply how reality works.
But how we got the idea might help you wrap your head around it.
In classic phyiscs there was a little problem that was considered mostly a small oddity, the fact that a fast observer would experience electromagnetical fields differently that a resting one. Depending on your viewpoint an electric field would look like a magnetic field and vice versa.
The only mathematically working solution to explain this behavior would be that time passes at a different pace for different observers, that there is no universal “now” that all viewpoints agree to be the same.
As you can imagine that idea was considered pretty insane, but then we did experiments to test it, and it actually turned out to be true. Every single experiment we constructed to measure that effect came out confirming it.
And today we have technology that wouldn’t work without correcting for time dilation. GPS satellites for example have to adjust their clocks to stay in sync with each other to be able to measure distances correctly
Dumbed down:
Matter does have a speed cap that is the speed of light. Any thing has to obey the speed limit. This includes movement in space and movement of electrons in the atoms and other particles.
A chemical reaction happens by moving electrons and other particles in space. So does a movement in space, it’s a movement of electrons and nucleus in space.
So, take a zero speed human with a mechanical clock in his hand and a electric clock in the other:
Person’s body uses the full speed of electrons and nucleus to experience time, mechanical clock can swing its parts full speed, and electrical clock can swing electricity at full speed.
Take the same person and two clocks and shoot him at 50% speed of light:
Human’s chemistry will happen at 50% speed cause 50% of the max speed is already used to move in space. The mechanical clock also will use 50% of speed to move in space and 50% to operate, electric clock’s electricity will also use 50% speed to travel in space, and only 50% will be available to operate the circuits. The result is that this second group will experience time 50% slower.
A comparison that comes to mind is the helicopter speed limit. It can’t practically have supersonic blades. So if you fly forward, your advancing blade will move in the air at the rotational speed plus the helicopter speed. If you want to fly forward at Mach .3 you need your rotor to have at maximum a Mach .7 blade tip speed relative to the copter. Conversely a stationary helicopter could, in theory, spin the main rotor at Mach 1 blade tip speed.
The faster you want the copter to fly, the slower the rotor can be. I’m digressing but that’s why copters can’t be practically faster than a certain amount.
Back to time, imagine an electron revolving around the nucleus of an atom. The electron can’t exceed speed of light, so as soon as you move the nucleus in a direction, the electron has to drop its revolution speed. Similarly that electron won’t perform a chemical or electrical duty at full rate as some speed is used to just keep up with the movement in space.
Now, this story works as long as you are a basic human with random job like me. I bet a true scientist wants to kill me for what I just said.
So time dilation and length contraction are two facts of the universe we just have to deal with. Another fact that we have to deal with is this: light travels at the same speed for any observer. So if you are sitting still and shine a torch, you see the photons flying away from you at the speed of light. If you are travelling 99% of the speed of light (LS), and you shine a torch forward, you will observe that the light still travels away from you at the speed of light. However, when you go talk to your friend who was stationary how fast the light came out of your torch, he will tell you that it travelled away from you at the speed of light. Not at your speed (99% LS) + LS, which would be 1.99× the speed of light. This is not allowed, according to current understanding of physics.
So one of the common ways to ‘visualize’ time dilation is the following thought experiement.
Consider you have a clock, and the way the clock works is a beam of light bounces up and down between two mirrors. Each bounce down and back up is 1 second. The light is travelling at the speed of light within the chamber of the clock. Now you and the clock start moving in a straight line. Now from your perspective, the light is still bouncing up and down once per second. However, your stationary friend sees that not only does the light have to travel up and down, it also has to move sideways to keep up with you. This means that the light in the chamber doesn’t travel the same distance, it travels a longer diagonal, and since its speed is constant, it must take more time to cover a longer distance. Let’s say from the point of your stationary friend, ths light takes 2 seconds to complete its path. [Here](https://youtu.be/hG_wUsqfHZs) is visualisation of what I’m talking about.
But how can that be? You see the beam ticking once per second, he sees it ticking once per 2 seconds. The only conclusion is that something is happening to your experience of the ticking of the clock. For you, time has remained the same, but from your friends perspective, your time has slowed down. The clock ticks slower.
This is not just a thought experiment. It’s been experimentally confirmed. It’s vital to account for this difference in [GPS satellites](https://www.astronomy.ohio-state.edu/pogge.1/Ast162/Unit5/gps.html). It’s also the reason why [we can detect muons from cosmic rays at ground level,](https://youtu.be/rVzDP8SMhPo), even though it seems like because of their extremely short lifespan they should all dissipate within a few km of reaching the atmosphere.
Think of the speed of light, light has no mass so it can go that fast, but mass trying to go that fast, mass experiences a time that slows down almost infinitely at that exact threshold of the speed of light, but that is just the exotic state of energy in our universe, we’re fuckin matter, if we go so many percent the speed of light, any changes to our direction equal g-forces that disintegrate us, but we are on a planet thrown at around 34 kilometers per second forward, downward at the sun, and the speed of light is like, hundreds of millions of km’s per second.. there’s also a thing where matter gains infinite mass as it reaches or passes the speed of light, and the correlation of that is with time passing slower closer to gravity sources, so factoring all that together, the squishyness of time that you like to live in, sloshed off the universe 18 billion years ago and is frothing off the surf that is our galaxy as our solar system in its particular arrangement of direction* and velocity relative to everything else.
thankfully i didn’t speak about quarks and their three ‘baryonic matter’ types winking between each type in moments of time or something regarding baryons and leptons.. i guess we are lucky.
This is the nearest I personally get to an explanation I can vaguely understand*: Because movement through space and time are like opposite ends of a seesaw (AmE teeter-totter). More of one, less of the other.
General Relativity sees time as effectively a dimension, like the three spatial ones we know. And the four are bound together into something we call “spacetime”. If you want to say where something in spacetime is, you need to know not just where it is in space but, but where in time as well. So “my chair now”, say, is a different place to “my chair at this time tomorrow”.
We all understand that in some way we’re all moving through time. In spacetime, you get from “my chair now” to “my chair at this time tomorrow” by moving in time, just like you’d expect – but because we’re treating it as just another dimension, you can put a “speed” on how fast you move, just like you can measure how fast you walk. And you can combine speed through space and speed through time to get a speed through spacetime. And the amazing, beautiful thing is that, the way the universe works, you **always get the same answer** when you do. **Everything** moves through that combined thing, spacetime, at the identical speed. And it’s the one we usually call “the speed of light”.
That means that something that is motionless in space is, in a very literal sense, hurtling through time at the speed of light. But it also means that, if it starts moving in space, it won’t and can’t move through time quite as fast – because the numbers have to balance. More space movement, less time movement. The faster it goes through space, the slower it goes through time. And if it could ever get to the speed of light, it would stop moving through time altogether (which is one explanation of why nothing physical that we’re familiar with can ever move faster than light – it wouldn’t be able to go slower through time than a dead stop, basically).
(It’s not easy to get our heads around things like this, because we’ve never experienced it personally – and never will. Objectively, we’ll always measure our time as moving at the same speed. It’s just when we compare ourselves with other things that the weird stuff happens.)
* *(Beyond the facts that (a) it’s fairly easy to show that it has to work like that if the speed of light is a constant, and (b) we have done many, many experiments to show that, yes, it does).*
Minute Physics did a good series of videos on [Relativity](https://www.youtube.com/watch?v=1rLWVZVWfdY)
The one on [Time Dilation and Length Contraction](https://www.youtube.com/watch?v=-NN_m2yKAAk) will likely help a lot.
Say you were walking north. For every step you take forward, you move one step north. If you were walking northeast, you’re still taking one step forward, but you’re only moving north at half the speed. Your overall speed hasn’t changed, but the amount of you move north has.
To transfer the same concept to time dilation, instead of north and east, there is space and time. Everything moves through spacetime at the speed of light, just like moving one step at a time. If you are physically moving at the speed of light, you will still be taking one step forward through spacetime, but all of your movement will be through space, and you won’t be moving at all through time. This is like walking all north and not at all to the east. On the other hand, if you are physically at rest, you’re still moving through spacetime at the speed of light, but you will only experience moving through time. In the north and east analogy, you’re still walking one step at a time, but you only experience moving east, not north.
While we commonly say you can’t travel faster than the speed of light, it’s more accurate to say you can’t physically travel faster than the speed of light. In spacetime, everything moves at the speed of light. But since most things physically travel much slower than the speed of light, these same things experience most of their journey in the dimension of time, not space.
If you want to understand how matter effects time, all you have to do is remember that matter warps spacetime. Look up the photograph we recently took of a black hole. It looks like a black spot surrounded in light. The spacetime of the black hole is so warped, light can’t escape. Just outside of the area where light can’t escape is an area where spacetime is still severely warped, but not so much as closer the to center of the black hole. Light moving through this area have to travel a longer distance than light further away, so time experienced in that area will slow down.
You see the fatter I get the greater attraction I have but I get older and redder. Because I’m Special. But if people see me feeling blue they know that I’m just slow and ask, “Why would you try to put so many teeth grinding false nerd jokes in one post with such vast inaccuracy?” to which I can only respond, “Tell that to the people who make EVERY FUCKING MOVIE!!!”
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