March 6th, 2011 by Michael Ricciardi
In a startling discovery by NASA astrobiologist Richard Hoover, ancient bacteria fossils have been found in a rare class of meteorite — called CI1 carbonaceous chondrites — and will surely set the astrophysics/cosmology community (and the world) abuzz with excitement and controversy.
Hoover claims evidence of bacterial microfossils “similar to cyanobacteria” (a form of blue-green algae which sustains most of the Earth’s oxygen supply). The tiny fossils were discovered in fractured slices of three different CI1 meteorites (named Alais, Ivuna, and Orgueil) and are estimated to be up to 10 billion years old.
Anticipating counter claims of Earthly contamination of the fractured slices, Dr, Hoover asserts that the prokaryote (primitive microbes lacking a nucleus) bacteria-like fossils are indeed indigenous to the meteorites and are “fossilized remains of living organisms which lived in the parent bodies of the meteors” (or other astral bodies such as comets, small moons, etc.).
Using an imaging technology called Environmental (ESEM) and Field Emission Scanning Electron Microscopy (FESEM), Hoover investigated the internal surfaces of the CI1 Carbonaceous meteorites, and subsequently produced images of large complex filaments. According to the paper abstract: “They exhibit features (e.g., the size and size ranges of the internal cells and their location and arrangement within sheaths) that are diagnostic of known genera and species of trichomic cyanobacteria and other trichomic prokaryotes such as the filamentous sulfur bacteria.”
Hitachi FESEM Secondary Electron Detector image at 1000 X of multiple filaments and sheaths embedded in Orgueil meteorite matrix
Hoover subjected the microfossils to an additional technique called Energy Dispersive X-ray Spectroscopy (EDS) , results of which indicate that the meteorite filaments are typically carbon rich sheaths infilled with magnesium sulfate and other minerals characteristic of the CI1 carbonaceous meteorites — providing further evidence that the fossil microbes are from the meteorites (or their parent bodies) and not the result of terrestrial contamination.*
Hoover is no astrobiological “cowboy’ prone to making controversial claims; he is a respected NASA scientist with a history of important contributions to the field.
The implication of all of this is that Life is potentially everywhere , or anywhere, in the universe, and that Life on Earth may have come from other planets.
However, if this evidence is confirmed, then it also affirms that life is just as likely to evolve here on Earth, too. Earth is a planet rich in biotic forms due to its hospitable geochemical and climatic conditions. And, bacteria are robust organisms capable of adapting and even thriving in extreme conditions (so -called extremophiles) such as in the anoxic, sulfur-rich environs of deep sea thermal vents, or even high saline conditions one mile below an Antarctic glacier.
Further, these fossils — if confirmed — will not provide a new biogenesis model, that is, an explanation of how life evolved in the first place; they merely shift the origin question into the depths of space.
Still, the discovery is astonishing and (potentially) revolutionary to the search for alien life in the cosmos.
Details of the discovery were published in the Journal of Cosmology late Friday night, along with an invitation to the world’s astrophysics and astrobiology communities to review/critique/confirm the data. Results of these critiques will be published in an upcoming (late March) edition of the journal.
* The fragments were subjected to a third analysis as well (quoting from the abstract): “The δ13C and D/H content of amino acids and other organics found in these stones are shown to be consistent with the interpretation that comets represent the parent bodies of the CI1 carbonaceous meteorites.”
UPDATE: As predicted, this “discovery” is earning no little skepticism, mostly regarding the lack of “respectability” of the journal, and, the confusion over images of bacteria (taken from Earth) used as comparisons to the alleged “alien bacteria”. This author notes also that, curiously, the imaged bacteria/microbes look remarkably well-preserved for having endured billions of years in a meteorite. For a brief criticism of this paper and research, check out the scienceblog post: Did scientists discover bacteria in meteorites? by PK Myers
Or, better yet, continue reading my follow-up commentary: In Search of Ancient Alien Microbes & the Origin of Life
Top Image: Ivuna CI1 meteorite filament (0.8 μm diameter) with dark lines C, partially encased in thin carbon-rich sheath.
Credits: FESEM and EDS imaging – NASA Marshall Space Flight Center
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