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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.space
Subject: Re: Unified Field Theory and space travel
Message-ID: <6084@utzoo.UUCP>
Date: Sat, 26-Oct-85 21:05:06 EDT
Article-I.D.: utzoo.6084
Posted: Sat Oct 26 21:05:06 1985
Date-Received: Sat, 26-Oct-85 21:05:06 EDT
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Organization: U of Toronto Zoology
Lines: 34

> 	I'd be interested to know if any of the new theories will cause
> reconsideration of some of Einstein's theories of relativity. I'm particularly
> interested in the speed of light being a limiting factor for space travel.

Reconsideration of the General Theory of Relativity is virtually certain,
partly because it appears to be incompatible with quantum mechanics and
partly because it contains major internal anomalies like the possibility
of the Tipler time machine.  [Briefly, intense rapidly-spinning gravity
fields can be used to build a time machine with unlimited range into both
past and future.]  Alas, General Relativity is just basically the current
theory of gravitation.  The Special Theory of Relativity, which sets the
various speed-of-light limits, is on much firmer ground and is unlikely to
be invalidated by new theorizing.  Of course, it is always possible that
some subtle way to bypass it may be found.

> Most people agree that as long as speed-of-light restrictions apply, it is
> impractical for intelligent life forms to travel to different star systems
> (unless, of course, their solar system is about to blow up).

Fortunately, wrong.  Within relativity, starships are slow and expensive, but
they are neither impossible nor impractical.  In recent years the literature
on interstellar travel (notably the JBIS "Interstellar Studies" issues) has
contained dozens of starship and starprobe concepts.  For example, if you
ignore a couple of decades of engineering development and the associated
funding delays, we have the technology to build antimatter rockets right
now.  There are any number of ways to reach tens of percent of the speed
of light, which suffices for interstellar flight within human lifetimes.
Not for interstellar commuting, mind you; near-term interstellar trips are
likely to be long enough that you could not make many in one lifetime.
For that, we need either highly-relativistic travel or (preferably)
faster-than-light travel.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry