Mars may have been a "blue planet" with an ocean the size of today's Arctic Ocean, a new study suggests.

“The presence of liquid water [on Mars] is a broad topic that includes rains, rivers, lakes, as well as oceans,” says Ezat ...

Spacecraft orbiting the Red Planet have helped researchers map out an ancient coastline that surrounded a large ocean billions of years ago ...

Earth and Mars in comparison. Mars has only about 10.7 percent of earth's mass but is roughly half its radius. Mars remains a true puzzle, but not for the reasons most people would think. Sure, ...