Saturday November 22, 2008

'Salty water may have ended life in Mars'


Too much saline: The frozen layers of Mars' high northern latitudes in this file photo. The blue colors indicate water ice, the Martian equivalent of permafrost. Scientists said on Saturday that Mars' salty water might have killed micro-organisms inthe planet. Picture: EPA

Monday, February 18, 2008

LIFE 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 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. Life anywhere else would leave atmospheric traces of gas produced by organisms.

Another theory cited by Knoll, "a large meteorite may have sterilised life on Mars".

In December the US 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.

AFP