Some scientists see ancient coastlines on Mars.
The northern hemisphere sits lower than the sourthern hemisphere, leaving a long coastline if an ocean once existed. More than a decade ago, Tim Parker looked at Mars and saw Utah. Parker, a geologist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., had earlier studied an ancient, dried-up lake bed in western Utah. Where the waters once lapped against the land, he often found telltale signs of erosion. With a careful eye, he sketched out two sets of shorelines.