# wondering about faster than light signals

Discussion in 'Physics & Math' started by nanok, Dec 18, 2001.

1. ### Brainz0Registered Senior Member

Messages:
44
Rigid particles

No.

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3. ### CrispGone 4everRegistered Senior Member

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1,339
Some elaboration...

Hi all,

Nanok, I think I may assume that you will not feel satisfied with Brain0's "No"

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. Allow me to elaborate a bit on his (correct) answer.

You cannot just "align" atoms or building blocks of matter: first of all you have a quantum uncertainty at that level, and this implies that you cannot hold a particle perfectly still. You need to subject every building block to a force - or in more common quantummechanical language, a potential - that more or less keeps the building block at its place (or pulls it back into its place in case of a distortion). Because this potential is responsible for keeping those building blocks where they belong, you can only move the particles by changing that potential. Hence the theoretically maximum possible speed at which a configuration of building blocks can change is the propagation speed of the force (already assuming that the building blocks react instantly to a change of the potential). This maximum speed is the speed of light.

Since in all practical cases you cannot change the potential that keeps the building blocks into place, this maximum speed is never reached. The best you can do is partially move some particles (most of the time a lot less than the speed of light for macroscopic objects) and watch the effect propagate along the rod you constructed. I'm not entirely certain that the deformation will propagate at the speed of sound in the material - as some people mentioned above - since there are a lot of effects to consider for different kind of building blocks. In either case: it's not faster than the speed of light.

Bye!

Crisp

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5. ### Brainz0Registered Senior Member

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44
Particles, etc.

Nanok & Crisp..

It gets even worse than that. There are no ultimate "particles". In QM all particles are instances of field effects; at base, only fields exist. To be crude, only twitches of space-time+ which persist and interact.

So there are no ultimate billiard balls. The effort to reconcile physics with intuitive images of hard little things is wasted effort. It cain't be done 'cause it ain't so.

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