Here's the post from Bruce Moomaw. He appears to be saying he *was* skeptical until he read Cockell's paper. Cockell apparently is positive towards the possibility.

Bob Clark

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From: "Bruce Moomaw" <moomaw@c...>
Date: Thu Sep 26, 2002 9:01 pm
Subject: Re: Life on Venus?

----- Original Message -----
From: "David M Harland" <dave.harland@n...>
To: <ISSDG@yahoogroups.com>
Sent: Thursday, September 26, 2002 3:59 PM
Subject: Re: [ISSDG] New member

> >Hi to all,
> >
> > I´m an amateur astronomer portuguese. A friend of mine: Paulo
> >Guedes talked to me about this list. I hope to learn a lot with your
> >help.
> >
> > A question for now: what do u think about this notice of
newscientist:
> >Acidic clouds of Venus could harbour life
>
>
>
>
> Carl Sagan would have loved it! He speculated upon this way back
> before space probes ventured out there. I don't recall the details
> though.

I sneered at the possibility -- until I read Charles S. Cockell's detailed
and astonishing piece "Life on Venus" in the Dec. 1999 "Planetary and Space
Science". (This isn't available for free on the Web, but I have a copy and
will scan it into the ISSDG file vault within the next few days.)

My reasoning had always been that any Venusian cloud particles containing
microbes would quickly waft down into Venus' lower atmosphere and roast
those microbes before they could reproduce. But Cockell's article includes
a detailed analysis claiming that bacteria multiply quickly enough that they
could easily keep up with such a destruction rate to maintain a stable
microbe population in Venus' clouds! If he's right (and that, admittedly
is a very big "if"), then, as he says, there is no really strong argument
against the possibility that bacteria evolved on ancient Venus (which
probably did have large surface bodies of water for several hundred million
years), and some of them evolved to survive in the concentrated sulfuric
acid of Venus' clouds (since some bacteria flourish in equally concentrated
sulfuric acid on Earth).

One other note: it seems increasingly likely that Europa's ocean also has a
high level of sulfuric acid, which if true would force any Europan microbes
to survive in a similar environment. But Europa's ocean, if it is acidic,
would have been highly acidic from the beginning, which may well have
prevented complex organic compounds from combining to form any form of life
there in the first place. Any early bodies of water on Venus, on the other
hand, would have been no more hostile to the evolution of life than those on
early Earth (or Mars) -- allowing ordinary bacteria to appear there and
later evolve into the complex specialized chemistries of those
acid-resistant microbes on Earth.

At any rate, it's at least possible enough that I will be looking forward
with interest to the results from that improved Venus entry probe to analyze
atmospheric trace gases in very fine detail which is rapidly gaining favor
as a near-future Discovery mission -- assuming it collects cloud particles
for analysis, as it surely will. Weirder things have happened...
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