With data from a camera and spectrometer on the rover's robotic arm, researchers found that the rock, dubbed "Esperance," is a relic of a wetter time on Mars when life may have been possible. [Ancient Mars Could Have Supported Life (Photos)]

 

"Water that moved through fractures during this rock's history would have provided more favorable conditions for biology than any other wet environment recorded in rocks Opportunity has seen," Opportunity principal investigator Steve Squyres, of Cornell University, said in a statement.