Liquid water once shaped the Martian landscape dramatically, carving valleys, filling lakes, and forming vast oceans. Billions of years ago, during Mars' early days known as the Noachian and Hesperian ...

For years, scientists have been intrigued by mysterious dark streaks running down the slopes of Martian cliffs and craters. These marks, called slope streaks and recurring slope lineae (RSLs), have ...

WASHINGTON, Oct 8 (Reuters) - Two decades of observations by a pair of orbiting spacecraft have enabled scientists to track the whirlwinds called "dust devils" that regularly pirouette across the ...

Planetary scientists agree that Mars used to have liquid water on its surface and a water-rich atmosphere, far different from its current arid state. But an accounting of all the sources of water to ...