[GZG] FTL was Re: A number of scientists respond to Hawking's concerns about Aliens

On Mon, May 10, 2010 at 8:25 AM, Indy <indy.kochte@gmail.com> wrote:
> * - an interesting side topic to all this is is the subject of
interstellar,
> FTL, travel. Being a romantic, I am in the camp that believes someday
we'll
> figure it out and go. But there are strong cases against it ever being
> possible (as we perceive things now). First, if you can go FTL, you
can send
> a radio message to a destination, then beat the radio waves to the
target.
> So in the case of Arecibo-1974, it will be ~25,000 years before M13
> civilizations hear us, but in the meantime we might have FTL'd out
there in
> our starships, found them hostile, and be engaged in an
> interspecies/interstellar war.  Or discover they are vastly more
powerful
> than us and we're trying to hide - but oops, radio signals are coming!
>
> Another even more damning case against FTL travel is gravity. You
generate a
> gravity field because you are composed of some mass. If you FTL to
another
> star, say 10 light years away, an observer sitting at the midpoint
between
> where you were and where you are will see you appear in two different
places
> at once - AND (let's say they have the technology) detect your
gravitational
> influence at the same time from two separate locales. This means
you've
> effectively doubled your mass in the universe, at least for the
particular
> observer's location (and in the plane orthogonal to the FTL line you
flew).
>
> I'm sure there are counter-arguments to this, but I haven't worked
them
> through yet.

My understanding is that all of this is predicated on nothing ever
traveling faster than the speed of light.  Once we find the bit that
does, we get to call all of the above a gravitic/optical illusion and
chalk it all up to not knowing enough yet.

I think we live in a universe where either time travel is possible
(which I think would invalidate every choice anyone ever made) or we
live in a universe where our  scientists don't yet know it all and
some hack will allow us to get there in a reasonable amount of time
without violating causality.  I suspect the universe hates causality
violations way more than really fast travel, so I suspect that it will
allow really fast travel.  I also suspect that the universe has a
peculiar and sometimes cruel sense of humor (like letting us see
really really far but not letting us GO there), so I could be wrong,
but I trust the universe more than I trust imperfect human
researchers/scientists working with a minuscule portion of the cosmic
junk pile.  And I don't think the universe is a conscious entity in
any way, just that acting like it is provides a tool for understanding
certain bits.

-- 
Ryan Fisk
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