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Re: FW: starship-design: Interstellar travel-using vacuum..ur poi nt?

Hi Group,
Hope I got this right. First time I've used a mailing list.

Walker, Chris wrote:

> Bjorn,
> I meant that I agreed that FTL travel was *necessary* for attempting serious
> interstellar exploration, rather than I thought FTL travel was *possible*.
> I'm still learning much about the various theories regarding  this subject,
> so do not feel qualified to comment on whether or not it is possible -
> that's why I was curious as to Kyle's beliefs in FTL flight.

"Serious Interstellar exploration" - what does that involve? What are you trying
to achieve and on whose timescale? The Galaxy can be explored by replicating von
Neumann probes in a few hundred thousand years. That's pretty serious
exploration. I guess it's not "Star Trek" timescale [22% of the Galaxy had been
surveyed in 300 years, according to one episode] but then who's counting? If you
want a rapid survey of planetary systems then invest in gravity-lens telescopes
or something equally powerful. Then you could map planets across tens to
thousands of light years.

> The planet-hopping method may be a more realistic/achievable goal in the
> shorter term (next century), given that without a major breakthrough in
> propulsion technology, FTL flight may not be achieved for some considerable
> time.

AFAIK there's not much chance of interstellar travel on a human timescale within
50 years. By 2050 I expect particle beam propelled micro-probes will be
possible, but not much else.

> It seems to me that production of a working reactionless drive is more
> within our immediate reach than breaking the light barrier.

Seems FTL is more likely than inertialess drives. At least we know of physical
processes that have involved FTL in the past [cosmic expansion], whereas there's
nothing known that can alter inertia. Haisch and Puthoff's electromagnetic
theory of inertia is a start, but there's no guarantee that inertia can be

> However, even to
> go from planet to planet within "a decade or so" per hop - whilst far
> quicker than anything we could acheive today - would make for slow
> exploration of our surroundings.

Like I said it'd be easier with a telescope. We travel to other stars not to
explore, but to stay and live. That's the only reasonable justification. Until
someone builds a cheap FTL drive that is. How about a Superspace Translocator?
Transfers matter from one point to another via a short-cut through all eleven

> Hence my belief that FTL travel is
> necessary for serious and long-distance space exploration.
> Does anyone know what is (theoretically) meant to happen re. time dilation
> when you travel FTL? (eg. travelling back in time?)

Time reversal is supposed to occur, though I could never work out why. "Events
preceding their effects" - one result of space-like motion [FTL], though I still
don't see how. A distant observer might see the events as occuring out of order,
but how does that then violate causality? Locally nothing odd has occurred. No
one has ever gone FTL so who can say?

Using the Alcubierre drive [if the energy problem can ever be solved] it's
possible to travel FTL without time distortion because locally the ship would be
static. Surrounding the ship though would be extreme space-time distortions with
bizarre time-flows.

As for wormhole travel the time distortion would depend on the relative motions
between the mouths of the 'hole. A traversible wormhole has no fatal space-time
distortions, but will there be any such out there in the Galaxy. There'll be
natural ones, but they might not be suitable for humans. The only way to know
would be to send probes in, and big time flow differences could mean a long wait
for a returning probe.

Adam Crowl