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Q & A: Can you transmit information faster than light with solid rods?

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Most recent answer: 12/09/2016
Q:
Hi, Great initiative, this! I have a question about a trans-galactical typewriter. If you move a solid object, all parts of it move with the same speed/acceleration. So if I do a thought experiment, and take a very, very long metal rod and I move it at one end one cm forward, the other end will move one cm forward at the same time. So, let me now connect the hammers of an old-fashioned typewriter here on Earth with a similar typewriter on Mars. Would the not my message arrive instantly on Mars, about 12 minutes before the video recording of me typing arrives on Mars? If the end of a rod does not move in the same way as the beginning that I'm moving - how much is then the difference? Would one be able to do a real live experiment here on Earth to measure the difference (with the speed of light?)
- Ton Sledsens (age 54)
Utrecht, The Netherlands
A:

Hello Ton,

Nope, it doesn't work.  The transfer of information on a rod can go no faster than the speed of sound

in the rod which is considerably slower than the speed of light. 

A detailed explanation can be found at  https://van.physics.illinois.edu/qa/listing.php?id=6797

LeeH


(published on 12/09/2016)

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