Mars had liquid water a billion years longer than we even thought possible

Valleys much younger than well-known ancient valley networks on Mars are evident near the informally named “Heart Lake” on Mars. This map presents color-coded topographical information overlaid onto a photo mosaic. Lower elevations are indicated with white and purple; higher elevations, yellow.
Credits: NASA/JPL-Caltech/ASU

Lakes and snowmelt-fed streams on Mars formed much later than previously thought possible, according to new findings using data primarily from NASA’s Mars Reconnaissance Orbiter.

The recently discovered lakes and streams appeared roughly a billion years after a well-documented, earlier era of wet conditions on ancient Mars. These results provide insight into the climate history of the Red Planet and suggest the surface conditions at this later time may also have been suitable for microbial life.

“We discovered valleys that carried water into lake basins,” said Sharon Wilson of the Smithsonian Institution, Washington, and the University of Virginia, Charlottesville. “Several lake basins filled and overflowed, indicating there was a considerable amount of water on the landscape during this time.”

Wilson and colleagues found evidence of these features in Mars’ northern Arabia Terra region by analyzing images from the Context Camera and High Resolution Imaging Science Experiment camera on the Mars Reconnaissance Orbiter and additional data from NASA’s Mars Global Surveyor and the European Space Agency’s Mars Express.