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Scientists studying soil samples from NASA's Curiosity rover have discovered that a carbon cycle similar to the one that sustains life on Earth once played out on the red planet.

While it's unclear whether Marsever supported life, its current harsh environment may be due to an "imbalanced" carbon cycle.

"Mars seems to have been habitable for its first billion years and that waned very quickly," Ben Tutolo, a space researcher at the University of Calgary, Canada, told DW.

Mars once had a thick atmosphere full of carbon dioxide capable of trapping heat in a Martian "greenhouse effect." This enabled liquid water to exist on a warm surface.

But today, Mars is a dry and cold planet with water concentrated in the form of its frozen polar ice caps. Mars scientists have long asked themselves a question: Where did the carbon go?

The Tutolo-led analysis of surface samples taken by Curiosity, today published in the journal........

© Deutsche Welle