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Here we are again. Another sensationalist announcement of the discovery of various species of fossilized "extraterrestrial" bacteria, found within one or more carbonaceous chondrite meteorites. These silicate-rich, rocky meteorites, more than other types, may have had their structures penetrated by water, organic material or primitive forms of life at some stage in their long history.
The discovery (awaiting confirmation) is the work of Richard Hoover, NASA astrobiologist, who has been analysing Antarctic meteorites for over ten years. In an article published in the Journal of Cosmology, Hoover claims to have found colonies of a new species of fossilized cyanobacteria (extremely resistant to harsh environments) and therefore concludes that they are extraterrestrial in origin.
Hoover, and other researchers, exclude the possibility of terrestrial contamination by bacteria that were present at the era of the meteorite fall.
The announcement of the discovery, made in an unconventional way and with unusual conviction, has stimulated both great enthusiasm and scepticism. In response, the
Journal of Cosmology has invited 100 experts to review Hoover's claims, and has invited a total of 5000 from various fields to comment.
Of course, criticism and comments will be published in the next few days in the same journal, but given the repeated publicity that the journal's director has given the article, one can't help but be sceptical.
After the recent discovery of quite terrestrial
bacteria in Mono Lake, that, due to their unique qualities have shaken the world of biochemistry, it does seem imprudent to conclude that a bacterium is extraterrestrial just because it has never before been seen. If we consider that 99% of the species that have ever lived on Earth are now extinct, how many as yet unknown forms of fossilized bacteria are yet to be discovered?
For now, the only certainty associated with the claims of Hoover, is that it's the latest attempt to shift the origin of life on Earth into space, as if comets in the Oort cloud or extra-solar planets or their satellites presented better conditions for the emergence of life than the primordial Earth.
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