Rover Finds Signs of Old Streambed NASA's Mars rover Curiosity has spotted pieces of an old streambed where water rushed by billions of years ago, scientists reported at a news conference on Thursday. "It just seemed like someone came along the surface of Mars with a jackhammer and lifted up a sidewalk that you might see in downtown L.A.," said John Grotzinger, the mission's project scientist. From the size of the rounded pebbles embedded in the slab, the scientists estimated that water was flowing about a yard a second and was between ankle and hip deep. NASA has found bountiful evidence of liquid water on early Mars when it might have been warmer, but this was the first observation of an ancient streambed. Curiosity is looking for carbon-based molecules which, together with liquid water, could have provided all of the necessary building blocks for life.