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Posted by rgregoryclark on October 30, 2006, 12:22 pm
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David Williams wrote:
> -> Martian Soils Point to Ancient Acid Ocean--And a Dearth of Life.
> -> "Despite being separated by thousands of kilometers, Martian soils from
> -> Gusev Crater and Meridiani Planum have proved broadly similar in
> -> parts--rich in chlorine and sulfur. Recent high-precision measurements
> -> have shown that phosphorus--the critical energy carrier in all known
> -> forms of Earth life--is equally abundant in such patches of Martian
> -> dirt. And the only explanation for such similar soils in disparate
> -> locations is a large, acidic ocean, according to a new paper published
> -> today in the November issue of Geology."
> -> http://www.sciam.com/article.cfm?chanID=sa003&articleID=000A1326-800A-153E-8
>
> -> The researchers discount the possibility of life because on Earth the
> -> phosphorus found would be absorbed by life.
>
> Life on Earth doesn't launch phosphorus into another dimension. It uses
> the element, but doesn't destroy it. When an organism dies, the
> phosphorus it contains returns to the environment. So life has no
> effect on the overall concentration of phosphorus, and measuring the
> concentration has no impact on the probability that life is or was
> present.
>
> The text you quoted does not say anything about the probability of life
> on Mars. It does say that phosphorus is useful to Earth-life, and that
> phosphorus is present on Mars. But its main point is that the soils at
> Meridiani and Gusev have very similar compositions, which may indicate
> that a large ancient ocean covered both sites. This would make ancient
> Mars a much more watery world than has previously been thought.
>
> dow
In the various news releases from the authors of the research paper,
they suggest the concentrations of phosphorus seen would not be
expected if the oceans contained life.
I haven't seen the full paper, but I gather they are arguing the
phosphorus concentrations and ratios are the same at the two widely
separated sites because there was a large scale ocean present AND
because this phosphorus was floating *freely* in the waters.
Bob Clark
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