A meteorite recovered in Antarctica did not contain evidence that primitive life forms existed on Mars, according to two research groups publishing in the current issue of Science.
NASA scientists announced last year that a 13,000-year-old meteorite thought to have come from Mars had been discovered. They believed that the potato-sized rock contained evidence of ancient bacterial life, prompting further analysis of the rock at labs around the world.
The first-published analyses of the chemical evidence, in two separate reports, concluded that most of the meteorite's organic material came from earthly contamination.
Dr Jeffrey Bada, of the Scripps Institute of Oceanography in California and colleagues at the University of California at La Jolla, the Jet Propulsion Laboratory in Pasadena and the University of Hawaii, said the chemical samples they examined might have come from the Antarctic ice where the meteorite landed.
And colleagues at the University of Arizona studied carbon-14 in the samples, the radioactive breakdown pro duct of decaying carbon atoms routinely used to carbon-date fossils. They found too much carbon-14 for it to have come from Mars.