New images of Mars suggest the Red Planet had large lakes on its surface as recently as three billion years ago.

The evidence comes from Nasa's Mars Reconnaissance Orbiter (MRO) which spied a series of depressions linked by what look like drainage channels.

Scientists tell the journal Geology that the features bear the hallmarks of being produced by liquid water.But they appear to have formed much later in Mars' history than many thought possible, the researchers add.

The team, from Imperial and University Colleges London, studied pictures of several flat-floored depressions located above Ares Vallis, a giant gorge running some 2,000km across Mars' equator.The hollows are about 20km in diameter.

WUSTL-led Moon mission is finalist for NASA's next big space venture

Robotic lander would collect rocks from far side of Moon

Dec. 31, 2009 -- Nearly 40 years after the Apollo astronauts first brought samples of the Moon to Earth for study, researchers from Washington University in St. Louis are leading an effort to return to the Moon for samples that could unlock secrets of the early Solar System.

Known as MoonRise, the proposed Moon mission is one of three finalists now bidding to become NASA's next big space science venture, a $650 million mission that would launch before 2019.

The MoonRise lander, unmanned and robotically controlled, would scoop up about two pounds of pea-sized lunar rocks and return them to Earth for further analysis.

"The samples would provide new insight into the early history of the Earth-Moon system," said Bradley Jolliff, Ph.D., principal investigator for the proposed mission and research professor of Earth and Planetary Sciences in Arts & Sciences at Washington University.