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”?

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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

To add to the many many “speed of sound in the material” comments: all that is true, but even if you had a magical material that was somehow perfectly rigid with an infinite speed of sound, the far end of a five-light-year-long rod will still take at least five years to move. Cause and effect can’t propagate faster than lightspeed, no matter how you set it up.

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