From: Eugene Leitl (eugene.leitl@lrz.uni-muenchen.de)
Date: Sat Sep 16 2000 - 07:49:25 MDT
Damien Broderick writes:
> If that's the universe we inhabit, what's the ultimate foreseeable
> transport system?
>
> 1) Fire ahead a stream of, say, very fast low-mass nano von Neumann devices
> with redundant minimal information, able to build assemblers once they find
> a source of convenient construction materials and abundant energy, which
> deploy a receiver able to instantiate the signal that's being sent in their
> direction. Or
Sounds good to me. After you fork (keeping a backup copy until you ack
arrival in good shape at the other end) you should be able to cover
interstellar-neighbour hops directly with 0.95 c, or so, if using a
(redundant cloud of, lest you meet a dust grain in transit) gray sail
(made of, say, lightweight carbon truss cloth, operates at 2000 K)
probes driven by a circumsolar microwave phased array, and express you
(stored as lattice defects in a crystal, of a self-repairing (because
of radiation background) molecular memory) upon arrival. If you travel
as a cloud, you can distribute redundancy over other nodes in transit,
reducing probability of losing bits of you. Decceleration is done by
the usual detachable double sail trick. Subjective travel time: zero,
unless you insist to travel at full clock (a few subjective megayears
in transit, unless you hug c *real* close). Of course, then you will
have to wait a little before you can travel to the next star, until
you construct the abovementioned star-pumped radiation source. After
that setup time, subsequent travels can occur either as photons
(bandwidth imo way too low), as routable matter packets (a kind of
interstellar TCP/IP) or verbatim (gray sail probe), without further
decceleration.
A sequence of such launchers could bring a relatively macroscopic
probe (containing antimater fuel for decceleration) to high fraction
of c, allowing speedy (single-hop) intergalactic travel.
I'm not sure beings will at all want to travel. It sure reduces
interaction latency talking to the guys at the other end in person,
but the complexity of the travelling critter is necessarily limited
(if you occupy cubic miles of nanocircuits, you're pretty immobile),
and the target culture will be very different. As will be the culture
you depart from, by the time you come back.
> 2) Develop a self-extracting signal able to interface with some plentiful
> natural condition -
Good idea, but I have not the foggiest on how to do this. Don't think
it can be done with photons, unless there's someone smart at the other
end already.
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