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

Ancient shoreline features hint that water on Mars once formed a vast ocean.

Mars, now a dusty world of rusted rock and thin air, once carried enough water to transform its face into something far more ...

Three billion years ago, you could have stood on Mars and watched a river spill into a sea. That picture is still speculative ...

Using images from cameras on Mars orbiters, an international research team has discovered structures on Mars that are very ...

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

A primitive ocean on Mars held more water than Earth’s Arctic Ocean, and covered a greater portion of the planet’s surface than the Atlantic Ocean does on Earth, according to new results published ...

A vast ocean likely covered one-third of the surface of Mars some 3.5 billion years ago, according to a new study conducted by University of Colorado at Boulder scientists. A vast ocean likely covered ...

Mars – dusty, dry, and desert-clad – was once so rich in water it had not just lakes, but oceans, according to a new study.

A vast ocean likely covered one-third of the surface of Mars some 3.5 billion years ago, according to a new study conducted by University of Colorado at Boulder scientists. The CU-Boulder study is the ...

Mars may have been a prime vacation spot millions of years ago, according to a new study on its coastal deposits. The data came from China’s Zhurong rover, which landed on the Red Planet on May 14, ...