Sunday, February 17, 2008
Life on Mars may have been snuffed out early
Salty water may have snuffed out life on Mars: scientistsLife on Mars may have been snuffed out early on because the water there was too salty, a biologist involved in exploring the red planet said here Saturday.
"Mars has been a very dry place for a very long time," said Andrew Knoll, an expert member of a team operating two US robots that are currently exploring Mars. "The best place to look for life is in the earliest history," he added.
"It was really salty and difficult for micro-organisms to survive in this water," he told reporters, citing discoveries by the robots which back up earlier theories that strong concentrations of minerals killed off life.
He was speaking on the sidelines of the annual meeting of the American Association for the Advancement of Science (AAAS) that opened here Thursday.
The discoveries by the robots roving the planet, dubbed Spirit and Opportunity, cannot confirm whether life ever existed on Mars, however.
"If there is a habitable niche, it's underground" on the planet, said the head scientist for the mission, astronomist Steven Squyres of Cornell University in New York state. Life anywhere else would leave atmospheric traces of gas produced by organisms.
According to another theory cited by Knoll, "a large meteorite may have sterilized life on Mars."
In December the US space agency NASA said the Sprint robot had discovered nearly pure silicon on Mars.
Squyres said this silicon forms near natural hot water sources or volcanic outlets, which give off natural gas. On Earth, living microbes are always found in such situations.
The roving robots are still going despite having passed their expected performance life by three months. They have been operating for four years.
Posted by SANJIDA AFROJ at 4:04 PM