> Any opinions on the Rare Earth theory that seems to indicate that
> complex animal life is quite rare in the Universe? I saw an article
on
> it at abc.com a while back and am now reading the book.

Opinion? Yeah; it seems to be pretty much the epitome of hubris: "I'm
so special that ALL OF CREATION was put here just for me and no one
else."

> One of the areas covered is that there is likely a galactic
habitable
> zone.

"Habitable" for whom? Is carbon/water-based oxygen/CO2-breathing the
only possible option for life? I think not. The promiscuity of these
elements probably means that it is one of the more common versions,
but it seems more than a little presumptuous to declare it the only
one.

> Brief summary:  not too close to the center of the galaxy where
> the increased gamma rays and increased number of stars packed
together
> create an environment that would discourage the formation of complex
> animal life.

There's that "only if it's like me" thing again.

> Then, further out at the periphery of the galaxy, they
> claim that the resources needed to create a planet with a liquid
metal
> core simply don't exist. Also, we are in an area between spiral arms
> where stars are scarce and so we have virtually no chance of being
> affected by other stars going super nova. In other words, we appear
to
> be in an ideal locality and most stars are not. Also the Sun is a
rare
> star ... 95% of all stars are smaller with smaller habitable zones
> around them.

"Habitable" for....

> It has a life of 10 billion years, which would allow the
> time needed for complex animal life to evolve.  Larger stars have
too
> short of a life-span.
>
> There is much more, but I am struck by the fact that we live on a
> special planet (only one with plate tectonics, for instance,
> which makes it possible for us to live),

And we know this how? Having visited--for that matter having
observed--exactly zero extra-solar planets, I'm not sure how the
authors reach the conclusion that Earth is THE ONLY PLANET IN THE
UNIVERSE to have plate tectonics.

> orbiting in a stable manner around a
> special star that is in just the right sort of place in the galaxy
to
> encourage complex animal life.  There is much more in the book of
> course. I recommend Rare Earth highly, by Peter Ward and Donald
> Brownlee, both from the University of Washington.

Going back to the top, what qualifies as "rare"? The occurrence of
human beings who duplicate me *exactly* in height, weight, hair color,
eye color, shoe size, interpupillary distance, and overbite is
probably pretty "rare", but there are billions of them who don't.
Given that there are orders of magnitude more options for variation
once you stop restricting yourself to bilaterally-symmetric erect
bipeds of the carbon/water/etc. persuasion, it seems reasonable that
there are billions of billions of billions of beings who differ from
me even more.

I don't particularly want to slam my UDub neighbors but, from the
information presented here, it doesn't sound too promising; opinion
buttressed by specially-selected "data" is not science.

Besides, the folks at Roswell already know we're not the only ones
around....


Steve Dirickson   WestWin Consulting
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