Re: FTL, ether and wind

Crown-Horned Snorkack <chornedsnorkack@[EMAIL PROTECTED]
> wrote:
>Just why would FTL lead to time travel?
>
>Because the simultaneity is relative, for the slower than light
>communications?

Because there _is no simultaneity_ as such in relativity. You literally
cannot
measure a well-defined time interval between spacelike-separated points.
This
means that there are always some frames where ANY pair of such points has
one
seen as occurring before the other, and always some other frames where the
SAME
pair has the second seen as occurring before the first. As long as one
point
is not in either the past or future light cone of the other, you can't
escape
this.

As long as you're going slower than light, you're confined to the future
(and
past) light cones of any event-point you go through on your trajectory.
The
moment you're going FTL, you are _outside_ both light-cones of every
event-
point on your FTL trajectory ... so suitable rearrangement of frames (via
acceleration to different velocities) for a pair of FTL trips can get you
ending up inside the past light-cone of the point you started from. Time
travel.

>But why should inertial frames be equivalent when it comes to FTL?

Because if they're not, then you have to figure out what the theory is
that
covers FTL trips AND reduces to relativity, _exactly_, when things are NOT
faster than light. Finding a way to go FTL does not invalidate all the
data
we already have; any New Theory has to account for all that data PLUS the
new stuff. This is the difficult part of physics, and is why so many
crackpots
have No Clue that their magnificent new Theories are trash from the
get-go.

>If you can send a ****p or a message from point A to point B and back
>in zero roundtrip time, you can compare the real simultaneity of
>events as established by FTL with the outcome of lightspeed signals
>sent through ordinary space.

There's still no simultaneity. I think that word does not mean what you
think it means.

>Also, what happens if Earth turns out to be subject to strong, indeed
>relativistic ether wind?

Then we have to figure out why it never shows up at all in any
slower-than-
light experiments. My Michelson and Morley T-****rt wants to talk to you.

>Is it possible to come up with a noncontradictory metrics where ether
>itself expands?

As long as it reduces to what we already know on the stuff we already know
about, knock yourself out. If it doesn't, you HAVE to explain why. (Note
that
Lorentz contraction is already an example of "well, things ****ft
themselves
around in such a way that we never see this effect at all however we try
to
look for it", so it can be done at times...)

Dave "paint your whiskers green" DeLaney
-- 
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