Nearly three weeks after the Mars rover Opportunity encountered the first meteorite ever discovered on the surface of a foreign planet, its sibling, the Mars rover Spirit, stumbled upon a native Martian rock that scientists claim provides strong evidence of the existence of liquid water during the Martian past. The rover spent nearly 13 earth days drilling into the rock, analyzing its interior and taking pictures, despite reduced energy due to dust storms. The investigation of the rock, nicknamed Peace, revealed a large quantity of sulfate salt in the rock’s interior — a substance that may have been deposited by liquid water.