[ExI] Faster than light??

[scerir]

Adrian Tymes:
> I do not see why FTL automatically means time travel.

Maybe the question can be also re-stated as "Though there exist reference frames 
in which superluminal photons would reach detector, by the clock of an observer 
in this frame, earlier than they were emitted, is it impossible to send photons 
back to their source prior to their emission in the proper time of the source?".

There are papers trying to answer to that question.
http://arxiv.org/abs/gr-qc/9807067
http://arxiv.org/abs/0708.0561
http://arxiv.org/abs/gr-qc/0204022
http://arxiv.org/abs/hep-th/9202090
http://arxiv.org/abs/quant-ph/0506027