Gale Crater, the region being explored by NASA's Curiosity rover, isn't the only place on Mars where ancient microbes may have thrived.
New evidence from NASA's senior robotic Mars scout, Opportunity, shows life-friendly water once mixed with telltale, clay-bearing rocks that now lie on the broken rim of Endeavour Crater, an ancient 14-mile wide basin on the other side of the planet from Gale.
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"If I were to go Mars early in time and wanted to do a well, I'd do it there," planetary scientist Ray Arvidson, with Washington University in St. Louis, told Discovery News.
"It's like drinking water," he said, as opposed to the "acidic goo" Opportunity found at a previous site.
"This would have been a niche for whatever life at the time existed," Arvidson said.
The finding dovetails with similar discoveries made by newcomer Curiosity, which, unlike Opportunity, is outfitted with a drill, onboard chemistry lab, and other instruments to hunt for potential life-friendly habitats. Opportunity's mission -- to find signs of past water -- was more basic.