In its five years of Curiosity rover exploration on Mars, the robotic rover has discovered an indication of chemical stratification in the ancient lake on Mars. This finding indicated that billion years ago, one particular lake in Mars was similar to the lakes on Earth.

The chemical stratification on the ancient lake was found by the team from Los Alamos National Laboratory after a comprehensive examination of the photos from Curiosity rover exploration on Mars. Curiosity rover took the photos in Gale Crater, which was a lake about billion years ago. According to the Planetary Scientist at Los Alamos National Laboratory, Roger Wiens, there is an indication of a physical difference between the deep water and shallow one in the Gale Lake.

“We’re learning that in parts of the lake and at certain times, the water carried more oxygen,” Wiens said about the photo of Curiosity rover exploration on Mars from the Gale Crater. "But we have to remember that at the time of Gale Lake, life on our planet had not yet adapted to using oxygen."

Gale Crater was estimated to be a lake around three billion years ago. In the crater, there are many oxidizing agents near its surface and less oxidant in the deeper, indicating a difference in chemical structure in the water. Based on the photo from Curiosity rover exploration on Mars, Wiens and his colleague were also able to determine redox classification and published their finding in the journal Science vol. 356/6341.

Curiosity rover exploration on Mars started five years ago. The rover was launched from Cape Canaveral, Florida on Nov. 26, 2011, and reached Mars nearly one year later. Curiosity landed on Mars in Gale Crater in August 2012 and began its mission to explore Mars.

The main mission of Curiosity rover exploration on Mars is to investigate the climate and geology in the red planet. Within five years of exploring the planet, Curiosity has given valuable data of the possible life forms on Mars and important geological data.