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 ...

A remarkable discovery on Mars has provided one of the clearest timelines yet for the existence of an ancient ocean on the Red Planet. Researchers have identified a vast mineral-rich “bathtub ring” in ...

Until recently, Mars was studied only through telescopes and some data that was recorded from early spacecraft. It was thought that Mars' polar regions were the only significant reservoirs of ice, ...

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 ...

We were as excited as anyone when MARSIS (the Mars Advanced Radar for Subsurface and Ionosphere Sounding) experiment announced there was possibly liquid water under the southern polar ice cap. If ...

Astronomers have filled a large gap in knowledge about Mars' water cycle. Their research on water percolating from surface to aquifer could change the picture of what early Mars was like, suggesting ...

For years, scientists have been looking for signs of liquid water just beneath the surface of Mars. The problem, though, is that the observations from various orbiting probes have been maddeningly ...

A new study casts doubt on a phenomenon that was previously believed to show water flowing on the surface of Mars. Since the 1970s, scientists have studied dark streaks seen on Mars' cliff sides and ...