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”?

637 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

No, the pushing force you exert on the stick will, like any other kinetic force transfer (like shock/sound waves), flow down the stick at the speed of sound for that material.

You can think of any kind of matter like a bunch of balls connected with springs. The speed of sound is the strength of those springs. The higher it is, the shorter the delay between one ball being pushed and it starting to push on it’s neighbour.

If you shove them faster than they can react, you’re just gonna tangle up the springs and deform the material.

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