From: Hal Finney (hal@rain.org)
Date: Mon Dec 16 1996 - 11:32:33 MST
From: John K Clark <johnkc@well.com>
> On Sun, 15 Dec 1996 Eliezer Yudkowsky <sentience@pobox.com> Wrote:
>
> >>John
> >>neither Special, General, or any other theory I've heard of
> >>says "The speed of light is whatever I make it".
>
> >Eliezer
> >Curved spacetime = tilted light cones.
> [...]
>
> Well OK, Tipler found a solution in General Relativity that shows that an
> infinitely long, extremely dense cylinder made of Neutronium (the stuff of
> Neutron Stars) and spinning at almost the speed of light would be able to tip
> a light cone enough to act as a time machine, but there are two very important
> problems.
>
> [...]
Actually today there are several ideas for FTL travel, including
wormholes (discussed at length on this list a few years ago) and
the Alcubierre "warp drive". These do raise the difficult question
of time travel. I found a detailed discussion of the problems with
these methods and various proposed ways of working around them at <URL:
http://www.physics.purdue.edu/~hinson/ftl/FTL_part4.html >. It is part
of a FAQ from rec.arts.startrek.tech but it is by a physics grad student
who seems to know his stuff.
Hal
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