The news from Meridiani Planum continues to be encouraging. A special issue (Dec. 3) of Science offers eleven articles by scientists connected with the Mars rover missions, this marking the first peer-reviewed presentation of data from the Opportunity rover. The articles cover Opportunity’s first 90 days exploring the Eagle Crater, before it moved on to the large crater called Endurance.

From Steve Squyres, Cornell professor of astronomy, who led the team
of rover scientists along with Dr. Ray Arvidson of Washington University (St. Louis), as quoted in a Jet Propulsion Laboratory press release:

“Liquid water was once intermittently present at the Martian surface at Meridiani, and at times it saturated the subsurface. Because liquid water is a key prerequisite for life, we infer conditions at Meridiani may have been habitable for some period of time in Martian history,” according to Squyres, Arvidson and other co-authors.

And in one of the papers he wrote for Science, “In Situ Evidence for an Ancient Aqueous Environment at Meridiani Planum, Mars,” Squyres writes:

“We cannot determine whether life was present or even possible in the waters at Meridiani, but it is clear that by the time the sedimentary rocks in Eagle crater were deposited, Mars and Earth had already gone down different environmental paths. Sample return of Meridiani rocks might well provide more certainty regarding whether life developed on Mars.”