Mars rovers explore hints of salty water CNN

NASA’s Opportunity rover sent back new images from Mars showing that small spheres previously found on the surface also exist below, in a trench the rover dug. Hints of salty water were also found in the trench, but much more analysis is needed to learn the true composition. Meanwhile Opportunity’s twin rover, Spirit, is about to dig a trench of its own in order to investigate soil that sticks to its wheels, suggesting the fine-grained material might be moist.