Re: starship-design: FTL idea

[kuo@bit.csc.lsu.edu (Isaac Kuo)]

Kyle R. Mcallister wrote:
>Timothy van der Linden wrote:

>> How nice it would have been if you'd not left out the calculations for this
>> transform... Now I still don't see why it goes backwards in time.

>It doesn't really go backwards in time. Just in some reference points.

This _includes_ ship A's reference frame.

The result?  The message, originally sent from ship A and echoed by
ship B travels backwards in time in _every_ reference frame.

Ship A receives its own message before it sent it.  _Everybody_ in
_every_ (sublight) reference frame agrees on that.

The paradox?  What if Ship A decides to maliciously send a different
message?

>Nothing goes backward in time. Even if you think causality violations
>prohibit FTL, no problem. FTL can be done without causality violations
>in EVERY REFERENCE POINT. See my follow up message.

This is only possible if relativity is violated.  For example, the
sort of FTL you see typically involves a special reference frame.
The only FTL speeds allowed are those which don't go backwards in
time in this special reference frame.  This means that in every other
reference frame, there are certain FTL velocities which aren't allowed.

With FTL travel and relativity, you can literally go back in time
and kill your grandfather.
-- 
    _____     Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
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