Posted on Saturday, February 23 2008 @ 14:05 CET by Thomas De Maesschalck
Scientists claim that while Mars had liquid water early in its past it may have been too acidic and salty for life:
"That's not a very good place to live, and it's a worse place for the kind of chemistry that we think gave rise to life on Earth," he said.
Knoll and other Mars scientists presented their latest results in Boston Friday at the annual meeting of the American Association for the Advancement of Science.
Related findings will be published in an upcoming issue of the Journal of Geophysical Research—Planets.
Spirit and Opportunity have been traversing the Martian surface for nearly 1,400 Martian days—well beyond their expected life spans of 90 days apiece.
The machines' most celebrated findings have come in geology, including evidence of water in the planet's past. But they've also shown that the water was high acidic and briny with dissolved minerals.
"At first, we focused on acidity, because the environment would have been very acidic. Now, we also appreciate the high salinity," Knoll said. "This tightens the noose on the possibility of life."
Even if life formed in such an unlikely scenario—there are salt-tolerant microbes on Earth, after all—they probably got a killing blow from meteorites.
About 3.9 million years ago Mars was pummeled by a heavy bombardment similar to the one that has pockmarked Earth's moon.
More info
at National Geographic.
