} It occurs to me that if the entire filter were due to events like this
} then for 1000 light years around we should see planets with advancing
} life. This would be a billion systems, so if we were the most
} advanced, it wouldn't be by much.
But the filter may well not be due solely to such events. Colliding
neutron stars, nearby supernovae, having your solar system drift through
a dust cloud, having a superjovian in your system to throw comets at
you... there could be a bunch of astronomical filters which we don't
easily know of because they were all absent for us, by definition.
I've just read Jared Diamond's _Guns, Germs, and Steel_, in which he
tries to look at the environmental factors behind Eurasian dominance.
Mostly "we" had more domesticable plants and animals than any one else,
on a bigger continent, oriented along a main climatic zone. It may in
the process shred L. Neil Smith's ideas about development and extreme
Ayn Randism. 1000 John and Jane Galts dropped into Australia 40,000
years ago would still get hosed by English convicts.
But it's given me more filter ideas. One, if developing technology can
be that dependent on environment, it helps my intuition that developing
intelligence might be as well, so until we learn more intelligence could
well be extremely improbable. Two, there is no guarantee a bunch of
hunter-gatherers will get out of that state. If there's a shortage of
domesticable plants (flip side: if Earth/Asia was improbably blessed),
or say if Africa had been a separate continent, so that the domesticable
large mammals of Eurasia got wiped out before their domestication was
needed, food production might never have happened, at least not in any
large way.
[Large animal thing: domesticated large mammals consist of 13 Eurasian
animals and the llama, the dog not being counted in this size class.
America and especially Australia hardly have any large mammals --
possibly because their first experience with hominids was with
Cro-Magnon hunters, who could have hunted them out of extinction
quickly. African and Eurasian animals had closer to a million years to
evolve a fear of large bipeds. My personal theory for why Africa lacks
domesticable megafauna is that they had too much time to evolve a fear
of bipeds; a few Eurasian species were still working on it, and thus
weren't too vicious or panicky. If Africa had been separate, Eurasia
would also have met Cro-Magnon, not proto-hominids, and their megafauna
might have gone poof.]
Diamond and Sulloway may be spearheading the turning of history into
science, although I'm quoting Michael Shermer of _Skeptic_ here. I
suppose _The Fourth Turning_ might be part of it as well, although I
admit I'm more suspicious of what I've heard of those ideas.
} Interesting - a star trek like universe out for 1000 light years, and
} then a vast emptiness from there on.
Sounds like Babylon-5, actually.
Merry part,
-xx- Damien R. Sullivan X-) <*> http://www.ugcs.caltech.edu/~phoenix
"Corruption is elected officials trading votes for their own advantage.
Democracy is when the masses do the same thing." -- _Cyteen_