[ExI] Faster than light??

[Adrian Tymes]

On Sun, Sep 25, 2011 at 2:49 AM, scerir <scerir at alice.it> wrote:
> 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?".

I believe that would be a fair statement.

Of the papers you linked, one seemed to assume "time = lightcone", then
superimposed different lightcones (and thus, different - incompatible -
standards of "time"), one seemed to assume time travel (in various ways)
to prove time travel, and the other three argued against.