Life on Mars WAS possible! Scientists say carbon residue in the Red Planet's rocks show it was habitable billions of years ago

It's one of the most profound questions in science – did life ever exist on Mars? Now, experts have unearthed evidence that the Red Planet was once habitable. Scientists have found carbon residue in Martian rocks, indicating that an ancient carbon cycle existed. And it means the Red Planet was likely once warm enough to sustain life. Researchers have long believed that, billions of years ago, Mars had a thick, carbon dioxide-rich atmosphere with liquid water on its surface.