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ALH84001 Nanofossils & NASA
I agree with Steve Arnold that Alex Heftman's website does raise some of the obvious questions about ALH84001. The two comments that I disagreed with most were: (1) the observation that all NASA funded scientists agree with the NASA/Stanford team's conclusions (i.e, NASA has squelched debate); and (2) the lack of evidence for the Martian origin of the SNCs. Anyone who reads the scientific literature or attends relevant conferences would probably disagree also.
Numerous scientists, including some NASA-funded scientists, do not believe the McKay-led team have found fossils.
Hap McSween (U. of Tenn) is one of the geologists currently analyzing the Mars Pathfinder data -- a NASA /JPL project. He and Ralph Harvey (Case / Western Reserve) both have published articles and even have a website espousing a high-temperature origin for the fossil structures in the ALH84001 carbonates -- and argue there is no possibility of life forming the little worm-like structures. Harvey is affiliated with the federally-funded ANSMET antarctic meteorite program which is working with the federally-funded NASA's Lunar and Planetary Institute and the Smithsonian.
Last Spring, at the American Association for the Advancement of Science convention in Seattle, I heard John Kerridge (NASA-funded scientist working on a Mars sample return mission) debate Chris Romanek (Savannah River National Lab and NASA-funded member of McKay team ). Kerridge doubted the fossil evidence and presented his findings with a slide show and Romanek did likewise for the proponents. A vigorous pro and con debate ensued before about 300 attending scientists. To the best of my knowledge, NASA has not rebuked anyone for questioning the conclusions of the McKay team.
The Martian origin for the 12 SNC meteorites is now generally accepted by most scientists who study these things. Several scientists -- including Bogard and Pepin -- discovered gas trapped in glass bubbles in one of the SNC meteorites. The gas was an almost perfect match with the Martian atmosphere as measured by the Viking probe (rare in science to achieve such a perfect correlation). Since then many of the other SNCs have been analyzed for gas inclustions and for petrographic chemical fingerprints that would link them to a Martian origin. Even the "ALH84001 nanofossil doubters" (McSween, et al) seem to accept the SNC analysis as sound science.
Ignoring ALH84001, Mars is suspected as a possible source for life for many other reasons, including surficial evidence that its surface once was partially covered with water -- now locked up in polar ice caps and possibly in permafrost and hydrated minerals. Even without ALH84001, Mars is one of the better prospect for finding life in our solar system. The Discovery series of missions targeted Mars for the Pathfinder and Surveyor mission well before ALH84001 became a "celebrity" meteorite.
While the jury is still out on whether or not the ALH84001 meteorites contain nannofossils, scientists (Stevens, et al, at Pacific NW Laboratory, Richland, Washington)have found similar living and fossilized nanobacteria that live in basalt over 2,000 feet under the surface of the Columbia Plateau.
I reluctantly agree with Alex's observation that NASA's senior officials did capitalize on all of the ALH84001 hoopla. I have a photo of Wes Huntress (NASA's chief scientist) testifying before Congress with a chunk of ALH84001 resting atop a regal pillow inside a glass display case. That was clearly a crass attempt to leverage ALH8401 into more Congressional funding and did cause a cynical reaction among many including those in the scientific community.
Steve Excell
Seattle, WA
excell@cris.com