Evidence of Ancient Martian Lake Clearest Sign Yet the Planet Once Boasted LIfe

Evidence Mars once hosted a freshwater lake marks the most convincing evidence yet the Red Planet sustained life at one point in its history, scientists announced Monday. 

Published in the journal Science, the study includes an analysis of sedimentary rock outcrops located at a site named Yellowknife Bay in Gale Crater. The results overwhelmingly suggested the 150-km-wide impact basin held at least one lake some 3.6 billion years ago.

"It is important to note that we have not found signs of ancient life on Mars," explained Sajeev Gupta, a member of NASA's Mars Science Laboratory and a professor at Imperial College London. "What we have found is that Gale Crater was able to sustain a lake on its surface at least once in its ancient past that may have been favourable for microbial life, billions of years ago."

Based on the analysis, the researchers determined the lake was probably calm and bursting with life-sustaining elements such as carbon, hydrogen, oxygen, nitrogen and sulphur, making it a petri dish for simple microbial organisms to thrive.

While the team previously found evidence of water on Mars' surface in other areas, the new discovery marks the clearest indication that Mars could have been habitable enough for life to exist.

"This is a huge positive step for the exploration of Mars," Gupta said.

The scientists were able to analyze the geology and chemistry of the mudstones by drilling into the rock using the probe Curiosity. Going forward, they said they plan on using the rover to explore the crater for more evidence of ancient lakes or other once life-friendly environments. 

"It is exciting to think that billions of years ago, ancient microbial life may have existed in the lake's calm waters, converting a rich array of elements into energy," Gupta said. "The next phase of the mission, where we will be exploring more rocky outcrops on the crater's surface, could hold the key whether life did exist on the Red Planet."