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 ...

Geological features on Mars suggest the planet once boasted rivers and broad coastlines around a vast ocean. The discovery provides the most direct evidence yet for the Red Planet’s former blue vistas ...