poly: frontier replicators et. al.

From: Richard Schroeppel <rcs@cs.arizona.edu>
Date: Mon Dec 22 1997 - 09:32:34 PST

I'd like to throw some cold water on the notion that the fastest
traveling replicator takes over the universe. Within our galaxy,
for example, the difference between the speeds .9999c and .99999c
isn't significant. For a trip of 100K light years, the faster
replicator will have a 9 year advantage in arrival time at the
far edge of the galaxy. That's enough for it to control the
star it arrives at, and a couple of nearby ones, but its zone is
limited to a 9 light-year radius. And that extra 9 at the end
of its velocity comes at a high cost: The faster seed must have
three times the energy of the slower, and three times the
(relativistic) mass. The launching system must devote at least
three times the resources to the fast probe, and perhaps a much
larger factor. So the slower system can send at least three
times as many seeds, and they will win more territory. The
fast seeder could try to compensate by heading further out on
the frontier, but there's nothing there: it's already reached
the edge of the galaxy.

This same idea seems to be applicable if "galaxy" is replaced by
"cluster", and "star" by "galaxy". So I don't see the fastest
travelers as being the winners. The optimal speed depends on the
cost of getting speeds near c, which determines the cost/benefit
of faster probes. Since the higher speeds are extremely costly,
the optimum might be .8c.

Some other thoughts inspired by the discussion ...
Can you speed up a star's burn rate by dumping in carbon?
John McCarthy (and another person whose name I've dropped) proposed
the notion of "captive asteroid" to gradually move the Earth away
from the Sun as the Sun warms up in old age.  The captive is used
to transfer energy and angular momentum from other planets to
the Earth, say from Venus and Jupiter.  The captive makes repeated
close encounters with the planets; each encounter moves a snippet
of E and L from the planet to the captive or vice versa.  The control
effort required on the asteroid is minimized by planning sufficiently
far ahead -- a butterfly flaps its wings the right way a few encounters
ahead of time for steering.  The idea also allows snowballing:  you can
begin with a boulder operating on mountains to move the mountains,
which then move small asteroids, etc.  Each step requires the same
time scales, a few million orbits (linear in the mass ratio).
This might be useful (in the long view) as a way to collide stars.
(It seems unlikely to benefit intra-galactic replicators, but
might be a way to harvest energy for inter-galactic efforts.)
We might well be the first intelligent replicators in our light
cone, perhaps because evolution took a few lucky turns.  We might
examine the biologically static periods in our planet's life
history for clues as to the hard/slow steps.  If we are to
believe the conventional wisdom (I'm a skeptic), life originated
on the planet within a couple of hundred My after cool-down
permitted liquid water.  Then cells appeared, and maybe 1Gy later
multi-celled organisms.  Eventually sex was invented, and "species"
became meaningful.  Later we get sensors, nervous systems, light
detection, and the Queen's Gambit Declined.  Maybe the hard steps
are hard because they require an anti-Darwinian mutation to be
quickly followed by an unlikely triumphant over-compensating
mutation.  The development of intelligence and civilization doesn't
qualify as a slow step here.  [Accepting this line of thought
requires buying into the notion that these later steps are less
probable than the origination of life itself, because they took
longer.  That's why I'm skeptical.]
Rich Schroeppel   rcs@cs.arizona.edu
Received on Mon Dec 22 17:26:09 1997

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