The announcement in 1996 that a multi-billion year old meteorite from Mars showed signs of ancient microbial life attracted tremendous public attention but the results were subsequently discounted, though never completed refuted, by the studies of other groups. For a summary of the Allan Hills 84001 meteorite controversy, see Life on Mars? – Smithsonian – May.2005.
An electron microscope image from the Allan Hills 84001 meteorite
Back in February of this year there came a study by a team of scientists from NASA’s Johnson Space Center in Texas and the Jet Propulsion Laboratory in California that reported signs of “biological processes” in a Mars meteorite that would have occurred hundreds of millions of years ago : Mars Meteorite Structures: Optimism for Alien Life? – Discovery News.
This week comes a study of a 1.3 billion year old meteorite with electron microscopes that sees cell-like structures that resemble fossilised biological cells seen in old earth rocks : Martian meteorite yields more evidence of the possibility of life on Mars – The University of Manchester.
Chemical maps of the ovoid structure obtained with an electron microprobe.
Chatzitheodoridis Elias, Haigh Sarah, and Lyon Ian.
Astrobiology. August 2014, 14(8): 651-693. doi:10.1089/ast.2013.1069.
More such results probably won’t change the dominant view that inorganic processes can’t be ruled out as the creators of these tiny structures. It will take studies on Mars, or more appropriately, below the surface of Mars, to prove whether or not there is life on the Red Planet now or that it existed sometime in the distant past.