Sci-Fic physics was Re: Faster Than Light Travel -

Alright, I will toss in my 2 cents about all this.  Tts been awhile
since
I took General Relativity so I might get some of the details screwy.

First, Tachyons.  The idea behind Tachyons is simple, special
relativity says you cannot go the speed of light with something with
mass.  If something is massless (light, neutrinos, gravitons, etc
etc-ons) it goes exactly at the speed of light.  Tachyons go only
faster then the speed of light.  As someone else mentioned, as you add
more and more energy to a tachyon, it goes slower and slower.  That is
how the equations work (screwy, eh?) but at no point do these things
travel slower then the speed of light.	The big problem with tachyons,
is there are no predictions on how they behave except that they go
faster then light.  Its hard to detect something when you have no clue
on how it should interact with the other things we understand (the
so-called tardyons).  Most likely, they do not interact at all.  When
you work on special relativity and start postulated things moving
faster then light all kinds of weird things start happening.  We once
had a problem on the tachyon telephone.  If we could create tachyons
and send information with them, it turns out you call backwards in
time.  This is a problem (ring ring, Hello? Sell ALL your Microsoft
stock now, it will drop through the floor in a week!) as casuality
just goes right out the window.  Hence, most physicists don't even
think about tachyons, because if they can interact with our universe
at all, they just break a whole lot of rules that we know and love.

So the other favorite way to travel faster then the speed of light is
by warping space-time.	Usually this involves something like a
wormhole.  Now the problem with GR is it starts to break down when you
talk about things called singularities.  A singularity forms at the
core of a black hole, for example.  There are black holes that can
form where you can fall through (you don't actually hit the
singularity) but know one has any clue what would really happen.  In
the past, when a theory has a singularity, it means we don't know what
is going on.  So we are gonna have to wait for a more complete theory
to understand this.  

cheers
brad