More space news and info at: http://www.coconutsciencela... - recent isotopic measurements made by scientists at NASA's Goddard Space Flight Center suggest that an ocean once covered approximately twenty percent of the Martian surface.
The video animation shows what is believed to be the approximate shoreline of this ancient ocean, which no longer exists.
Measurements were made using ESO's VLT, the Keck Telescope, and NASA's infrared telescope.