Re: Hard Sci-fi?

On Apr 20, 1:07 pm, Ben Crowell
<crowel...@[EMAIL PROTECTED]
> wrote:
> Leonard Erickson wrote:

> > Read the late Dr. Robert Forward's "Timemaster". for FTL that does
> > include time travel and *doesn't* require godlike amounts of mass or
> > energy.
>
> > It merely requires the existemce of matter with negative mass. Which
> > is not forbidden by theory. :-)
>
> > He even dealt with causality problems.
>
> Now you've got my curiosity piqued, but probably not enough to get me to
> read the whole novel.

It wasn't one of Forward's best.  The book did explore some
interesting issues of causality and determinism - it's not a complete
waste - but I found the characters flat and the plot rather
unengaging.  It was not on the level of Dragon's Egg or Rocheworld.

> What's the dodge that allows it to be done without
> large amounts of mass and energy?

Unobtanium.  In particular, bizarre aliens made out of negative-mass-
energy matter.

> Basically any strong curvature of
> spacetime requires that the stress-energy tensor be big.

It has been a while since I read it, but I recall the magnitude of the
negative-energy stuff being used to stabilize the wormholes was well
below that which would allow those kind of wormholes to be
stabilized.  They were fairly standard Visser wormholes, which require
fairly extreme "strings" of negative-energy-mass stuff.

Other science glitches I caught - the reactionless drive method would
have been dynamically unstable, and shining light on negative-energy-
mass would not reduce its temperature.

Luke