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Author Topic:   Good evidence for life on Mars?
roxrkool
Member (Idle past 989 days)
Posts: 1497
From: Nevada
Joined: 03-23-2003


Message 1 of 1 (50600)
08-14-2003 5:39 PM


I recently came upon this very interesting paper (pdf format) entitled, Elongated prismatic magnetite crystals in ALH84001 carbonate globules: Potential Martian magnetofossils. Here is the Abstract:
quote:
AbstractUsing transmission electron microscopy (TEM), we have analyzed magnetite (Fe3O4) crystals acid-extracted from carbonate globules in Martian meteorite ALH84001. We studied 594 magnetites from ALH84001 and grouped them into three populations on the basis of morphology: 389 were irregularly shaped, 164 were elongated prisms, and 41 were whisker-like.
As a possible terrestrial analog for the ALH84001 elongated prisms, we compared these magnetites with those produced by the terrestrial magnetotactic bacteria strain MV-1. By TEM again, we examined 206 magnetites recovered from strain MV-1 cells. Natural (Darwinian) selection in terrestrial magnetotactic bacteria appears to have resulted in the formation of intracellular magnetite crystals having the physical and chemical properties that optimize their magnetic moment. In this study, we describe six properties of magnetite produced by biologically controlled mechanisms (e.g., magnetotactic bacteria), properties that, collectively, are not observed in any known population of inorganic magnetites.
These criteria can be used to distinguish one of the modes of origin for magnetites from samples with complex or unknown histories. Of the ALH84001 magnetites that we have examined, the elongated prismatic magnetite particles (~27% of the total) are indistinguishable from the MV-1 magnetites in five of these six
characteristics observed for biogenically controlled mineralization of magnetite crystals.
(emphasis mine)
Besides the obvious interest in extraterrestrial life, the paper also gets into natural selection, which I found fascinating.
What do you think, good evidence?
------------
For more info on magnetobacteria, visit:
Magnetotactic Bacteria and Cal Poly
For more info on magnetofossils, visit:
The Magnetofossil Homepage
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Mods: I wasn't sure where to place this topic, so please move it as you see fit.

  
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