# Proof that time <0 for tachyons > c

1. Sep 16, 2016

1. The problem statement, all variables and given/known data

Derive the result DeltaT <0 for U> (sqrt(1-v^2/c^2)+1)/v/c)c

2. Relevant equations

DeltaT = u/l + (u-v/1-uv/c^2)1/l

Where:
DeltaT is the time for the tachyon to go and come back.
u is the velocity of the tachyon
l is the distance that the tachyon goes
v is the velocity of the receiving end moving away from the tachyon
c is the speed of light
3. The attempt at a solution

I tried to substitute values for u(2c),l(100m) and v(0.5c) but it gives me DeltaT = something/0 and I'm trying to get time less than zero, not infinite time.

I'm not sure that I need to put values in the equations to proof that DeltaT <0 for U> (sqrt(1-v^2/c^2)+1)/v/c)c .

2. Sep 21, 2016

### Algr

If you get time less than zero, doesn't that mean you have turned the tachyon into antimatter? Or does matter/antimatter not apply to tachyons?