# sending information over a wire--mechanically [duplicate]

Possible Duplicate:
Is it possible for information to be transmitted faster than light?

I've thought about this since I was a little kid. I know it isn't exactly feasible, but it still bothers me.

I hand you a really long wire, and we agree that "a long tug means 1, two short tugs mean 0", then you move off into the galaxy, a few light-years away from me. I proceed to give you information by tugging on the wire.

With a really tight wire, couldn't I talk to you faster than the speed of light?

## marked as duplicate by Qmechanic♦, Colin K, Manishearth, David Z♦Apr 10 '12 at 4:48

• Even a "really tight" wire, is not "infinitely" tight, which is what you'd need. – Lagerbaer Apr 10 '12 at 3:28
• In my humble opinion, I do not agree with closing the question. For example, we all know that perpetuum mobile cannot be created because this breaks laws of thermodynamics. However, if one proposes perpetuum mobile mechanism, it is instructive to crack it down - this way we can all learn something about physics. Proposed larger than speed of light travel was based on principle on transverse wave speed and replying to this question requires explaining the difference between the speed of crests (theoretically arbitrary) and speed of information (limited). Regards. – Pygmalion Apr 15 '12 at 13:27

I think the question was about transverse and not longitudinal waves. In case of transverse waves the wave velocity - speed of crests - goes with square root of tension/linear density ($v^2 = \frac{T}{\mu}$) and is therefore theoretically possible to be infinity for every material (large $T$, small $\mu$). However, velocity of information is still smaller than velocity of light.