Submitted by Unnombrepls t3_10rqr48 in askscience
Alfred_The_Sartan t1_j6ym2ll wrote
Reply to comment by Naive_Age_566 in extremely long stick additional questions? by Unnombrepls
This is a fantastic explanation. I was thinking it would all move together and was trying to figure out how a light years long stick would react. I was thinking that the whole thing would move at once and therefore information would travel faster than the speed of light.
DesignerAccount t1_j6yo5lv wrote
That's true for an ideal "rigid" stick/body, which is just a body for which shocks transfer instantaneously. Reality is that no body is perfectly rigid, obviously, and the shocks propagate depends on th density of the object. Hit a long stick on one side and feel the hit with a delay.
OPs question becomes even more interesting if you start making assumptions about the stick being super light, so really low density, so a normal human could potentially move it. Haven't figured out the answer, a convincing one, though.
lankymjc t1_j6z63dc wrote
I used to think that I had theoretically cracked FTL communication through the use of really long sticks (though the engineering would be its own impossible issue). Took me ages before finding out about compressing objects, which made me feel better because I was sure someone must have already thought of it and disproved it, I just couldn't find the answer until a few years ago!
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