If I were to take a really really really (light years) long stick and push something on the end of it, would it happen “instantly”?

1.05K viewsOtherPlanetary Science

Obviously theoretical but if I took a light year long stick and say pushed a button at the other end would that button be pushed at the same time for me as say someone standing at the button? How does the frame of reference work when physically moving something? And could that “work” as a method of instant communication?

In: Planetary Science

34 Answers

Anonymous 0 Comments

This is something that I thought about for a very long time before I found the answer!

Imagine the long stick was made of sponge. If you push one end, the other doesn’t move instantaneously – you’d see a “wave” of sponge travelling along it.

Turns out every material is like that – it’s just that things like metal do it so fast that we can’t detect it at normal human scales. This is why physicists say there’s no such thing as instant or simultaneity. It just appears that way to most people.

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