This 23 March, 2004 NASA Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater in Utopia Planitia on Mars. There used to be an ocean on Mars about three billion years ago and its remains can still be observed, Russian scientists said. “Our studies have shown that an ocean existed in the Utopia Planitia region on the Red Planet,” Mikhail Ivanov from Space Research Institute of...