Reanalysis of Decades-Old Data Reveals Signs of Life on Mars Scientific American

Previously dismissed claims for evidence of life in Martian soil samples collected more than 20 years ago now appear to have been right on the money. So says a University of Southern California biologist who recently reanalyzed the data and presented his findings last Friday at an astrobiology symposium held during the annual meeting of the International Society for Optical Engineering. Back in the 1970s, the NASA researchers who first studied the soil, which had been gathered by the Viking Landers 1 and 2, found clear indications of gas release that they believed came from living organisms. Others countered, however, that such gases more likely resulted from chemical reactions among highly reactive inorganic compounds in the soil, and the argument for life on the Red Planet fell by the wayside.