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 ...

NASA’s long search for liquid water on Mars has produced its most significant result yet: evidence of vast reservoirs buried deep in fractured rock beneath the planet’s surface. The finding, drawn ...

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 ...

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 ...

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...

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 ...

Mars is the fourth planet from the sun and has a distinct rusty red appearance and two unusual moons. The Red Planet is a ...

The rusty world is full of mysteries—and some of the solar system's most extreme geology. Learn more about Earth's smaller, colder neighbor.

A new study suggests Mars could help scientists understand how alien worlds evolve by showing how a once warmer, wetter ...