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Date: Tue, 19 Nov 2002 14:28:47 -0800 (PST)
From: Jerry Friedman 
Subject: RE: (urth) FTL Travel

--- James Wynn  wrote:
> Nicely done, but place our explanations side by side and I think you can
> see
> why I explained it the way I did .
> -- Crush
> -----Original Message-----
> From: Andy Robertson [mailto:andywrobertson@clara.co.uk]
> Sent: Monday, November 18, 2002 1:49 PM
> To: urth@urth.net
> Subject: Re: (urth) FTL Travel
> This is not quite accurate.
> What is accurate is that travelling FTL in one inertial frame, from the
> point of view of one observer,  will **always** be travelling back in
> time
> in another inertial frame, from the point of view of another observer.
> God may see the universe as a four-dimensional whole, as has been
> discussed.
> Travelling FTL requires that you have the vision of God - that you see
> time,
> not as a progression, but as a dimension
> ----- Original Message -----
> From: "Roy C. Lackey" 
> To: "urth" 
> Sent: Monday, November 18, 2002 7:09 PM
> Subject: Re: (urth) FTL Travel
> > Crush quoted and wrote:
> > >Don asks:
> > >Please explain.  Is this the usual SF take on FTL or is there a
> physics
> > >explanation that makes backward time travel the most likely?  I'm
> pretty
> > >ignorant on this.
> > >
> > >Crush responds:
> > >As one moves faster and approaches the speed of light, time slows
> down,
> > >exponentially, until time stops at the speed of light. I am informed
> by
> > >Stephen Hawking (not personally) that it takes an infinite amount of
> time
> > >and an infinite amount of energy to reach the speed of light.

"...that it *would* take..."?
> > >
> > >It is simple mathematics that as one moves faster than the speed of
> light,
> > >time moves in the opposite direction. No doubt, there are other
> > mathematical
> > >models.

I wouldn't call it simple mathematics.  What Andy Robertson is
talking about is that if observers moving with some velocities see
an object move from A to B faster than light, then all observers
with other velocities see the object move from B to A faster than
light.  You can use this fact to show if FTL travel or even
communication is possible, you can send messages to your own past.
This doesn't say anything about what would be experienced by
someone traveling faster than light, if such a thing is (were)
possible.  I think it probably isn't possible, and if it is, no one
has the slightest idea what someone traveling FTL would experience.

In reality, sending messages backward in time is often cited as a
refutation of FTL, a reductio ad absurdum.  In Wolfe's fiction,
time travel is possible already, so FTL is no problem.  Severian
makes this connection, by the way--it must be near the end of
_Citadel_, after the secret of the universe.

> > >Hence, a FTL generation ship is unnecessary.

That one I agree with (with an exception that's probably unimportant
to BotLS).  I see no evidence at all that the _Whorl_ is capable of
FTL.  I agree with Andy Robertson that Wolfe associates FTL with
transcendence, and would add that the _Whorl_ seems to be entirely
secular.  (I don't think I'm the first person to say that on the list.)

Jerry Friedman

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