Water on Mars: Images from NASA's Mars Reconnaissance Orbiter suggests that billions of years ago, as much as a third of the Red Planet's surface could have been covered with liquid water.
Scientists have spotted more evidence that an enormous ocean on Mars covered much of the planet's surface billions of years ago.
The latest clues were found in photos from NASA's powerful Mars Reconnaissance Orbiter circling the planet. The images show what appears to be an ancient river delta, which may have emptied into a vast Martian ocean that inundated up to one-third of the Red Planet long ago, a new study reports.
"Scientists have long hypothesized that the northern lowlands of Mars are a dried-up ocean bottom, but no one yet has found the smoking gun," study co-author Mike Lamb, an assistant professor of geology at the California Institute of Technology (Caltech) in Pasadena, said in a statement. [Photos: The Search for Water on Mars]
The new study does not provide the long-sought smoking gun, researchers stressed, but it further bolsters the hypothesis.
The team studied high-resolution images of a slice of the northern lowlands snapped by the HiRise camera aboard NASA's Mars Reconnaissance Orbiter, which can distinguish features as small as 10 inches (25 centimeters) on the Red Planet's surface.