By Brig Klyce
15 August 2010
At the Astrobiology XIII session, 3-5 August 2010, of this year's SPIE conference in San Diego, NASA scientist Richard Hoover showed more images that add weight to the case for fossilized cyanobacteria in meteorites. The fossils are found in carbonaceous meteorites of several types, including CI1 (example: Orgueil) and CM2 (example: Murchison). Here we present some typical and previously unpublished images from those meteorites.
The fossils are biological.
That the microfossils are the remnants of biological, once-living organisms is apparent from looking at them. Most resemble well-studied and recognizable filamentous cyanobacteria which are aquatic organisms long known as the "blue-green algae." These life-forms are among the dominant photosynthetic life forms in the oceans and lakes, but they also inhabit the polar ice caps as well as permafrost, geysers and volcanic fumaroles. These abilities make cyanbacteria ideal as potential life forms that could conceivably grow in the permafrost of Mars, the ice of Europa or in liquid water veins beneath the jet-black crusts of comets as candidate microbes that could conceivably be distributed throughout the cosmos by the agency of panspermia.
Chemical mapping shows that carbon and other life-critical bio-elements are distributed in the forms as appropriate for biological fossils, but the filaments are also infilled with Epsomite (hydrated magnesium sulfate), which was deposited in the hollow sheaths after the organisms died. Amino acids, nucleotides, and other life-critical biomolecules are found in the same carbonaceous meteorites that contain the fossils. The excess of L-amino acids, a property of the proteins in all living organisms known, is consistent with life — and with no known explanation by abiotic production processes (which yield equal numbers of the D- and L- forms). Clearly, the fossils found in the meteorites are biological.
Are they recent contaminants?
The major question is — were the microfossils present in the meteorites when they entered the Earth’s atmosphere, or were they left by modern microorganisms that entered the stones after they landed on Earth? …
Tuesday, August 17, 2010
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