[meteorite-list] absence of evidence is not...

[Darren Garrison]

http://www.popularmechanics.com/science/space/1282716.html

The most comprehensive study of the famous Mars meteorite has concluded it contains no evidence that
life once existed on Mars.

The study was sponsored by the National Science Foundation, NASA and the British Royal Society to
settle the controversial claims made four years ago that the Martian meteorite, ALH84001, harbored
evidence of life on the red planet.

The findings are contained in a report titled "Magnetite morphology and life on Mars," which is
scheduled to be published today (Nov. 19, 2001) in the Proceedings Of The National Academy Of
Sciences. The eight researchers who participated in the study claim that earlier findings were
seriously flawed. In the previous study, NASA-sponsored scientists concluded there were fossilized
structures that could have been created only by living organisms.

Today's report is particularly critical of the analysis of transmission electron microscope images.
These revealed lines of bright objects that were assumed to be magnetite crystals like those found
in terrestrial bacteria. Authors of the current report say that when they compared the crystals from
the meteorite to crystals from three strains of earthly bacteria, none matched.

"Although the similarities are intriguing, we believe that they do not provide evidence that the
crystals are Martian," the team concluded. The work was conducted at Arizona State University in
Tempe by Peter R. Buseck, Rafal E. Dunin-Borkowski, Bertrand Devouard, Richard B. Frankel, Martha R.
McCartney, Paul A. Midgley, Mihaly Posfai, and Matthew Weyland.