Re: starship-design: Many things...

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

Kyle R. Mcallister wrote:

>Have we measured Time dilation directly? Speed (.01C+) 

Yes.  We've confirmed it in clocks on aircraft travelling around
the world, on the space shuttle, GPS satellites (which simply
wouldn't work right if our calculations on time dilation were
wrong).  Also, we've confirmed time dilation in subatomic
particles in that their decay times dilate according to relativity.

>What if you carried your light/lightcone with you at FTL, in a way that
>eliminates TD and Lorentz contraction? 

The problems with FTL causing communication back in time have
nothing to do with the light cone of the travelling messages/ships
/beams/whatever.  It has everything to do with the reference
frames of the SUBLIGHT ships/persons/whatever which send the
messages/ships/beams/whatever.

>What if you were in an alcubierre ship, travelling FTL, and your power
>source died? Would you eliminate? 

It depends upon exactly how the Alcubierre metric was accomplished
in the first place.  Alcubierre never noted how it might be done,
although Pfenning and Ford proposed a rough method (which requires
more energy than their is in the universe, so...).

>What causes Centrifugal force EXACTLY?

Centrifugal force exactly does not exist, except as a useful
mathematical construct for use along with the Coriolis force
in doing calculations within a rotating frame of reference.

>What causes inertia EXACTLY?

No one knows.  That is exactly how far our understanding of
inertia goes.  We don't even know why inertial mass and
gravitational mass seem to be absolutely identical as far
as we can measure.  It's a useful factoid, of course, but
there's no proposed theoretical explanation.

>Is it at all possible that there is something we have yet to find which
>would provide a loophole for FTL? (not by 2050)

Of course.

>Kyle Mcallister

>Here's a dreadful thought: what if someday at .99999+C we find out that
>Einstein was wrong there? Bad news for timetravel.

What's so dreadful about that?  Time travel examples don't need
speeds that fast.  The one I posted didn't.  The FTL signal travels
faster, of course, but I only needed the Lorentz transformation for
the sublight ships A and B, which were going sublight.
-- 
    _____     Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
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