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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.space
Subject: Re: Time Retardation
Message-ID: <6150@utzoo.UUCP>
Date: Mon, 18-Nov-85 18:26:50 EST
Article-I.D.: utzoo.6150
Posted: Mon Nov 18 18:26:50 1985
Date-Received: Mon, 18-Nov-85 18:26:50 EST
References: <8511111807.AA01976@s1-b.arpa>, <399@sesame.UUCP>
Organization: U of Toronto Zoology
Lines: 18

> What happens if two ships leave with opposite vectors, and they both approach
> the speed of light relative to their initial frame.  The v above, relative to
> each other, would approach 2*c, giving a non-real answer.  Where am I goofing?

Velocity addition follows different rules at relativistic speeds.  The
velocity of one ship as observed from the other never exceeds (or reaches)
the speed of light.  So the FTL velocity isn't "real".

Note that imaginary numbers aren't necessarily the kiss of death for a
theory; the elaborate body of theory surrounding the still-hypothetical
tachyon has them everywhere, but they turn out to be unobservable.

> (Or is it time to invest in a FTL ship?  :-) )

Only if the dealer demos it for you first!
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry