X-Message-Number: 27293
Date: Sat, 29 Oct 2005 10:07:34 -0400
From: Thomas Donaldson <>
Subject: a bit on time travel

Re Time Travel:

Exactly how we got onto this problem in Cryonet I do not know.

I will add a bit of physics: even in terms of general relativity
time travel can become possible in particular universes. That's
an important step: no current theory forbids it. At the best,
they can come up with the idea that it may take too much energy
or time.

While I don't think about time travel very frequently I don't
do so not because I think it's impossible but because it looks
far enough away that we're not going to get it for a long long
time. And perhaps it would be a good idea to forget about
notions of impossibility and think more about possibility.

            Best wishes and long long life for all,

                 Thomas Donaldson

PS: Incidentally, time travel need not cause causality problems;
it's just that avoiding causality problems causes restrictions
on what a time traveller can go and do.

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