On Wed, 19 Jul 2000 firstname.lastname@example.org wrote:
> I think you're missing part of the point Greg was trying to point to from
> Robin's paper "Burning the Cosmic Commons". If *any* civilizations produce
> colonization, then the effects that Robin suggests will come to dominate
> the expansion.
I thought I had responded in previous points, but I'll reiterate it
here. If *any* civilization gets to the point that it *can*
colonize it is going to *look* to see where it should colonize.
We are going to have astrometric data on a significant chunk of
the stars in our galaxy (> 1 billion around 2015), we will also
probably have atmospheric data on any "near-Earths" around stars
within 100 light years about that time. So we will be able to "see"
where we are going. You are not going to want to go someplace
unless you have a fairly high certainty that it is "unoccupied".
That means that you have to look twice distance-to-star + at least
your trip travel time (say star @ 10 l.y., you take 60 years
to get there, then you are going to want to look out to 70 l.y
beyond that star for any signs of life). Even more difficult
you potentially want to be able to guarantee that any life on those
even more remote planets must be more than 70 years behind the
If you don't buy the above argument, then you have to make a concrete
case for civilizations "leaping" before the look. As we have gotten
more experienced (perhaps life has become more valuable) we tend to
do less and less of that. The only case I can see it happening in
is a planet/star destroying event that is anticipated far enough
in advance to flee it in world ships.
Now, I believe any civilization that has the capability to colonize is
going to know nanotech is possible, know that colonization without
nanotech is silly (because the post-nanotech probes/ships get there
first), and so will wait until nanotech is fully developed. Once
nanotech is fully developed it is dirt-cheap to build millions of
telescopes to conduct the careful surveys I've outlined above.
The civilization is most likely to discover an uncolonized galaxy
or a colonized one (because either of those is a much longer
time period than a partially colonized one). If it is uncolonized,
then you colonize out to the limits dictated by your advance knowledge
that is limited by the speed of light.
I would argue that the most likely situation is that that has already
happened because Lineweaver indicated that 76% of the possible Earths
in our galaxy are older than ours and most of them are much older.
> If nearly all star systems are inhabited by SIs that
> control all the matter at their star, then none of those entities are the
> ones who will expand, and you can leave them out of the calculation except
> as locations that gobble up probes.
No, you have to make an argument that a civilization would strike
out and start colonizing *knowing* that SIs existed. I've asked
this before -- would Columbus or the Pilgrims have attempted
to colonize North America *if* they had know it was occupied by
millions of people whose technological capabilities, political
preferences, etc. were unknown to them?
In the history of the Earth *most* of the colonization has occured
in situations where the colonizers thought the apples were "free"
for the picking.
> Those that send out probes of whatever kind will colonize everything. The
> first wave will be slow and low tech, but it'll be followed by a faster,
> higher tech wave, and so it will continue. Like the pilgrims who came to
> America, they'll be cut off from progress, possibly for the lifetimes of
> the individuals involved. But if they have any sense of history, they'll
> realize that later generations will be in contact with whatever galactic
> civilization ensues.
If the colonizers don't look then this may be right. If they do look
and see nothing, then Robin's colony waves makes sense. If they cannot
*prove* to themselves that they will not be stepping on some giant's
toes, then colonization should only occur when you have taken your
civilization to the highest possible levels because that is the
only way you can defend yourself if you piss someone off.
The question isn't what have we done in the past (colonized with
little knowledge of physics and a lot of arrogance) -- it is --
Knowing what you know might be possible, can you suggest the
*wisest* colonization strategy for civilizations around our level?
When I look out into the galaxy, I don't expect to see the people
who reproduced and colonized the most -- I expect to see the smartest
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