If tachyons travel faster than light does this mean they also travel backwards through time?

Answer 1

time's arrow is past- present- future(p-p-f), so imagine that a tachyon(T) is emitted from point "a" and is headed towards you at point 'b' then it is going to pass you to finally reach at point 'c'. now the normal progression of events in time ( p-p-f),and (a-b-c) in space. however taking light as the mean by which we can see things, then you will see the events occurring in a reversed chronological order, since T is faster than light then you will see its image at point "b" before its image at point "a', imagine it as a race between the light photons and the 'T', at point 'a' photons starts the race with 'T', T will normally win the race and reach point 'b' before the photons; at point b another photon hits the T in order to get you its image, it will have a closer starting point for your eyes, thus you will see 'T' at point 'b' before 'T' at point 'a', so in space you will think it is moving from 'b' to 'a', ( note that you will never be able to see 'T' at point 'c' , since 'T' is faster than light , light will never capture its image). this is why it seems to be moving backwards through time,i.e, (f-p-p).