November 26, 1997. Copyright, 1997, Graphic News. All rights reserved

MICROBIAL LIFE MAY STILL FLOURISH BENEATH SURFACE OF MARS
By Oliver Burkeman

London, November 26, Graphic News- MARTIAN LIFE Ð in the form of microbes Ð did exist and may thrive beneath its surface to this day, according to a group of geochemists writing in the December issue of ÔScientific AmericanÕ.
In their paper, researchers Everett Gibson, David McKay, Kathie Thomas-Keprta and Christopher Romanek describe why they think a Martian meteorite discovered in Antarctic ice shows microbial life flourished on the red planet millions of years ago Ð and may still do so.
ALH84001, as the 1.9kg (4lb) rock is officially known, became detached from Mars when a comet or meteorite hit the planet. It journeyed through space for 16 million years before landing 13,000 years ago, and was discovered in 1984 by a NASA researcher. Its origin was only established in 1993.
GibsonÕs team Ð from NASAÕs Johnson Space Center and the University of Georgia Ð put forward their theory last year. Now, they present the evidence.
Central to their claim are microscopic carbonate globules found flattened against the walls of fractures in ALH84001. These contain organic carbon molecules Ð suggesting the presence of life Ð and mineral deposits similar to those produced by terrestrial bacteria. Most importantly, they contain Ôunusual structuresÕ resembling bacteria fossils found on Earth. And carbonates, scientists believe, can only be formed in the presence of water in its liquid state.
Today, the Martian atmosphere is 95 percent carbon dioxide, rarely warmer than freezing-point, and devoid of liquid water, making surface life highly unlikely Ð though photographs taken by the 1976 Viking probes suggest surface water was widespread billions, and maybe just millions, of years ago.
But GibsonÕs team claim conditions underground could still nurture microbial life. In subterranean cracks and pores, they write, Ôit is entirely possible that if organisms existed on Mars in the distant past, they may still be there. Availability of water within the pore spaces of a subsurface reservoir would facilitate their survival.Õ
ENDS

Sources: Scientific American, The Planetary Society