"Michael Ash" wrote in message
t...
On Fri, 18 Jun 2004, gswork wrote:

ON the off chance you don't know, Fermi's paradox is basically - if
even conservative estimates suggest that adanced life in the galaxy is
abundant then even more conservative estimates show that the entire
galaxy should be explored already, so why aren't the aliens here?

various reasons are given as to why they're not : advaned life is
rarer than we thought, space travel is more difficult than we think,
they are here(!), they've put us in quarantine until we grow up,
civilisation destroy themselves at some crucial point etc etc.

Or we may simply be the first. Somebody had to be first, why not us? The
"paradox" holds about as much water as that theory that we must be near
the end of the world because exponential population growth means there's a
95% chance that any given person will be born within a lifetime of the
end, or however it goes.
I think the perhaps more 'likely' scenario, is that suitable conditions for
intelligent life, have only really become possible in perhaps the last
couple of billion years. In a sense you need to be looking at relatively
'late generation' stars, with the conditions for the first ten billion years
or more in the Universe, probably not being suitable for life. If you then
think that the propagation rate of Von Neumann probes will be several orders
of magnitude below light speed, and radio messages become unlikely to be
detectable after only a few hundred light years, even if half a dozen races
have managed to develop so far in the Milky way, the probabilities are still
against any of the probes being close enough to detect/respond to us.
The key assumption in the Fermi paradox, is that one or more races, a long
time ago, would have developed to the point, where they would have launched
self replicating probes, and as such therefore these should be visible. The
probability of surviving long enough, not just to get into space, but to go
interstellar, and design probes that can keep working, not just for
centuries, but billions of years, is to my mind low enough, that if the
timescales are reduced, no race may yet have got this far in our galaxy....

Best Wishes