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Given that the speed of light is the upper limit for changes to propagate through the universe; if you had a four light-year long indestructible rod and you move one end of the rod how long until the other end moves?
I'm not an expert, but I guess it would depend on the speed of sound in the rod.
Yes - https://www.youtube.com/watch?v=DqhXsEgLMJ0 is a nice explanation.
So about 6 terayears (1.9E+20 seconds) if it's made from the same steel.
This crashes the simulation.
42
That's distance, not time.
Well not above the speed of light, if I read the first sentence correct.
Somewhat related: let's say you're moving at 80% the speed of light away from earth. Then you turn on a flashlight and point it away from earth.
c
OK, so after 1 hour:
It depends. The light is definitely moving at c, no matter who checks and from everyone's perspective, but as a consequence of that the answers to those other questions change depending on how you measure. The coordinate system (technically the "reference frame") you choose changes the answer. Even more, time isn't the same for each frame, so you even have to specify for whom it has been 1 hour.
Instantly, unless the rod flexes