Do tachyons violate causality by traveling backward in time?

[munky99999]

http://scienceworld.wolfram.com/physics/CausalityProblem.html

If the tacheyon was going backwards in time, then how is this wrong, or contradictory?




Also, I'm not to sure of the definition of Causality, if it states event A must happen before B, then couldn't we further extend this to say ask long as time is moving forward. If time is going backward then would it not mean B before A?

 

[VBPhysics]

That problem is the result of A setting into affect the actions which result in B, say having a ladder kicked out from under you causes you to fall. if the events where to be connected faster than c, then you would fall before the ladder was kicked out from under you. Hence the paradox, you fall before some one kicks the ladder, and the causality has been affected. A no longer causes B because it happens afterwards.

 

[munky99999]

ya i get that, but if time is moving backwards to the tacheyon, would it not be perfectly fine for the tacheyon, hence we are making a difficult frame of reference. In the tacheyons frame of reference it would all look completely correct, would it not?

 

[cookiemonster]

I don't remember. Has anybody found a tachyon yet?

cookiemonster

 

[munky99999]

nope entirely theoretical.

 

[cookiemonster]

For some reason, I have a feeling they don't exist...

But just in case they do:

http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html

In particular, read the last couple of paragraphs concerning propagation of information via a tachyon.

cookiemonster