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December 09, 2013

Ancient Mars Lake Could Have Supported Life

by Steve Baragona

Mineral-munching microbes could have found a hospitable environment in an ancient Martian lake, according to new research.

Scientists say it’s the best evidence yet of conditions suitable for life on the red planet.

Earlier this year, NASA reported evidence of water on Mars that could have sustained life.

The latest research, published in Science, shows the Mars rover Curiosity has found iron and sulfur minerals in different chemical states at the bottom of an ancient lakebed.

Rock eaters

Those different chemical states show electrons can move around in that environment.

That’s significant because “if you can move electrons around, you’ve basically got food,” said geoscience professor Scott McLennan at Stony Brook University. “In principle, you’d have microbes that could eat the rocks and that’s very common on Earth [in caves and thermal vents]. They’re primitive life forms, but they’re very, very well known and very well understood.”

A string of research papers has suggested there could have been life on Mars, but this is the first time University of Tennessee planetary science professor Hap McSween has been convinced.

“Before, we’ve found evidence of ancient water. We’ve found this or that, various pieces of the puzzle, but never the whole package," McSween said. "And this place really does seem to have the whole package.”

The samples were taken not far from Curiosity’s landing site, in a geological formation known as Yellowknife Bay.

Life on Mars and Earth
 
The area appears to have been a lake more recently than researchers thought - though still nearly 4 billion years ago. 
 
That’s about the time life was emerging on Earth. 
 
“It could be that the two planets had emerging but very simplified life at the same time,” McSween said. “But we’re a long way from figuring out that this interesting lake deposit has any evidence of life.”
 
The rover is not equipped to look for fossil microbes that could answer once and for all the question of whether there was life on Mars. 
 
“Ultimately, what’s going to have to happen is to start the process of collecting samples on Mars [and] getting them ready to return them to Earth,” McSween said. “This certainly would be a prospective place to go and look for samples.”
 
Back to the plan
 
In the meantime, the rover is headed for Mt. Sharp, a 5-kilometer-high formation of layered rock.
 
“It’s like the pages of a book. You just work your way up through the history of Mars as it’s recorded in the sedimentary record,” McSween said.
 
Mt. Sharp is rover mission’s original target. The remarkable discovery of a habitable ancient lake is just a detour.