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 ...

There might be a hidden ocean's worth of liquid water below the surface of Mars, seismic evidence suggests. According to a new paper published April 25 in the journal National Science Review, ...