Re: FTL, ether and wind

: Crown-Horned Snorkack <chornedsnorkack@[EMAIL PROTECTED]
>
: If you have multiple frames where FTL could occur, how do you avoid
: time travel?

Is that the goal now?  Well, OK, but note that your originnal question
was 
    If the roundtrip time between A and B by FTL is exactly zero, and
    signals sent A to B at FTL and back B to A arrive after a finite
    time, how do you avoid a preferred frame? 

which doesn't involve avoiding time travel.  But if that's the goal,
then the usual way is some mechanism embodying the so-called
chronological protection conjecture.  Often illustrated by wormholes;
you can connect any two spacelike separated events with wormholes,
so there are "multiple frames where FTL could occur", but if you try
to move your wormhole ends to have a timelike separation (or indeed
establish any network of wormholes with a closed timelike curve), you
must first have a closed lightlike curve, and that would collapse your
wormhole network.  There are reasons to suppose this would indeed occur.

So.  You "avoid timetravel" because if you try it, your FTL widdget
implodes before you accomplish it.  (Note that this is not the same issue
Niven raised in "theory and practice of time travel", and turned into
a short story, but it has much the same effect).


Wayne Throop   throopw@[EMAIL PROTECTED]
   http://sheol.org/throopw