Curiosity Rover Finds Evidence That Microbial Life Once Existed on Mars
The saga of our attempt to find life on Mars has gone on for many years, but there have been several new developments recently. Curiosity found last month that there is significant evidence of a long lost lake on Mars, possibly confirming the long-held hypothesis that Mars was once a wet planet capable of sustaining life similar to that we'd find on Earth. Reinforcing that discovery is a study conducted by Nora Noffke, a geobiologist at Old Dominion University, which states that Mars photos taken by Curiosity contain evidence of microbial life on the Red Planet that is now extinct.
Curiosity took the above photo, as well as several others, while roaming through Gillespie Lake outcrop in Yellowknife Bay, which is thought to be a dry lakebed that underwent massive flooding billions of years ago. We are already fairly certain that Earth and Mars share a similar early history, and that Mars could have been host to microbial life. But Noffke believes that Curiosity's pictures not only depict dry lakebeds, but sedimentary structures that are similar to those built by microbes on Earth.
From the paper: "Sandstone beds of the 3.7 Ga Gillespie Lake Member on Mars have been interpreted as evidence of an ancient playa lake environment. On Earth, such environments have been sites of colonization by microbial mats from the early Archean to the present time."
Noffke asserts that there are distinctive geological features that the Martian structures and terrestrial structures built by microbes have in common, such as "erosional remnants and pockets, mat chips, roll-ups, desiccation cracks, and gas domes." She contends that if the same structures were found on Earth, then scientists would almost certainly conclude that the structures were the result of microbial civilization that had thrived in water that had since dried completely.
"The fact that she pointed out these structures is a great contribution to the field," says Penelope Boston, a geomicrobiologist at the New Mexico Institute of Mining and Technology. "Along with the recent reports of methane and organics on Mars, her findings add an intriguing piece to the puzzle of a possible history for life on our neighboring planet."
Like Curiosity's findings that there may be organic life on Mars, these results do not definitively confirm anything, but they bring us one step closer to bringing our "life on Mars" saga to its conclusion.