Re: Findings in Martian meteorites...


Posted by Uncle Al on Jan 20, 2004 at 10:53
(68.5.243.16)

Re: Findings in Martian meteorites... (peacepixy)

There was no biological evidence for biology in Martian meteorites. The physical evidence constituted microscopic mineral forms ("nanofossils") that were claimed to be consistent with biological origin. Even at that point, serious objections were raised: Unicellular life requires a minimum volume to contain its genetic code plus a minimal basis set of cell machinery and structure. If you go into the scholarly literature, you will see that the volume of these Martian "nanofossils" is hard by that limiting volume.

Google
science martian meteorite mineralization 640 hits

There is a growing body of evidence that the "nanofossils" are trivially reproduced abiological mineralizations,

http://www.mcgill.ca/reporter/32/13/astrobiology/mars/
http://www.impactlab.com/modules.php?name=News&file=article&sid=2396

"Nanoforms: A new type of protein-associated mineralization," Geochem. Cosmochem. Acta 65 63 -74 (2001)

"Non-biologic origin of 'nanofossils' in Martian meteorite ALH84001," Nature 390 454-455 (1997)

"Epitaxial growth of nanophase magnetite in Martian meteorite ALH84001 : Implications for biogenic mineralization," Meteoritics and Planetary Science 33 765-774 (1998)

Bottom line: There is no credible evidence for (past) life on Mars to date. If one of the two NASA rovers - one incoming, one sitting on its metal ass doing nothing for the past 20 days - find and image a lump of limestone, things change. One expects any/every water world to evolve life over a billion or three years. Whether it early on achieves sufficient complexity to give unambiguous survivable fossils remains undetermined.

--
Uncle Al
http://www.mazepath.com/uncleal/qz.pdf
http://www.mazepath.com/uncleal/eotvos.htm
(Do something naughty to physics)

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