Rocks, and Mars past
Studies have estimated that the present landscape of Mars was created about two billion years ago and little further processing has occurred. Researchers have now identified an impact-produced crater about 25 cm in diameter on a rock studied by the Mars Pathfinder. They suggest that fractures and angular shapes on other rocks are also related to such impacts. The dynamic processes may still be altering the rocks of the area of AresVallis, and these features can provide clues about the present and past of the red planet ( Science , Vol 285, No 5436).