From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Sun May 25 2003 - 10:35:23 MDT
On Sun, 25 May 2003, Eliezer S. Yudkowsky wrote:
> Maybe if
> there are unlimited resources Elsewhere, the stars would stay on.
There is a *lot* of mass, particularly H2 (or ionized forms),
still left around in gas/dust clouds. [These clouds can easily
run to hundreds of stellar masses.] Clouds recently generated
via a supernova would be particularly rich in the heavier elements
one needs for computronium (unless one wants to go to the trouble
of breeding these elements which might be very time/energy consuming).
The density of the clouds is low however. I'm under the impression
its a few particles per cubic meter (Amara might know better).
So I personally could never think of an efficient way to
concentrate the material but that doesn't mean one doesn't exist.
I've never studied the physics of Bussard collectors (Star
Trek deflectors?) or whether recent progress in space
technologies (e.g. R.M. Winglee's magnetospheric plasma
propulsion) might be applied creatively to allow the
matter to be efficiently collected/densified.
If it turns out that harvesting material that is in "free" space
is cheaper than lifting it out of stellar gravity wells then that
does seem like a *much* better evolutionary strategy (Spike & Damien --
there are some opportunities here for some really creative thinking --
just *how* big of a collector could one create? Does it have
to be physical, magnetic, etc.? What would a civilization or
computational architecture built around this look like?)
The fact that a fully evolved star based MBrain (one that uses
an "unmanaged" star as a power source) may be up to several
light years in size does begin to raise the question of
whether or not we have been thinking about this incorrectly
because the scales we typically think in are meters instead
of AU? Just as we never understood what nanotech allowed
(until Feynman/Drexler looked closely at it) because we
didn't think about things in terms of nm scales -- might we
perhaps be missing the boat in terms what advanced civilizations
look like, the Fermi Paradox, etc. because we aren't
thinking *big* enough?
If these thoughts are correct, and galactic gas cloud material
harvesting is much "cheaper" than star-lifting (or other methods
to get resources out of stellar gravity wells), then the stars will
stay "on" until all such clouds have been depleted.
So the explanation for the Fermi Paradox then becomes what
"SI" in their right mind would possibly want to use a star as
a source for resources (unless it happened to live in a very
impoverished part of the galaxy from the perspective of
atomic/molecular clouds)? Then the entire W. I. Newman &
C. Sagan ideas about "interstellar diffusion" become
entirely based on an extremely anthropocentric perspective.
As civilizations evolve, they *don't* migrate to the stars,
they *do* migrate to the clouds.
We could take this a little bit further. As has been discussed
on the list (and written about by Seth Lloyd and probably others),
black holes make great power sources. So the "advanced civilization"
bias on where to travel might be (1) A black hole with lots of
matter to throw into it; (2) Large easily harvested matter clouds
(preferably those enriched with heavier elements); (3) Someplace
rich in brown dwarfs (because they have more matter in minimal
gravity wells); (4) Someplace where one or more stars is about
to go supernova (because if one can solve the radiation damage
problem to ones nanotech [which is probably possible because
its a redundancy issue] then such locations aren't bad because
they are solving the "removal of the material from the gravity well"
problem without having to construct any of the star-lifting
equipment; (5) Lastly, typical star systems where one has to
ultimately do all of the back-breaking work of doing the
star-lifting to reduce the damn thing to something that
will last a trillion or more years (or as Eliezer would
probably prefer to stop unmanaged fusion processes entirely
so less of the potential energy is wasted).
Robert
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