I’ve only just learnt that the speed of light is really the speed of causality and I’m trying to understand it. I’m sorry if this is a stupid question but imagine I had a seesaw a lightyear long. I sit at one end and the other end lifts instantaneously. If someone was sat at the other end I would be lifting them faster than light could reach them. Their being lifted would be faster than the speed of causality. Is this wrong? Does one end of a seesaw dropping and the other end lifting not happen instantaneously with one another?
EDIT: Thank you to the people who have all responded so far. I can see that my thought that the two ends of the sawsee moving simultaneously with one another was the error in my thinking, and that the reason I thought this was due to scale and in reality a seesaw seems instantaneous but it’s not. Thanks again to those who took the time to reply and I’m grateful for your kindness.
In: Physics
>Imagine I had a seesaw a lightyear long. I sit at one end and the other end lifts instantaneously.
Your seesaw is made out of atoms. Those atoms do not transfer the momentum of your butt instantaneously between each other, there’s always some wiggle room. This wiggle room on a large scale translates to the speed of sound of a material. So depending on the material of your seesaw, it’ll only lift at the other end after one light year divided by the speed of sound of that material (likely tens of thousands of years).
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