NASA’s Mars rover Curiosity, which has been exploring the Martian surface for past 28 months in search of life, has finally found crucial geological and chemical evidence suggesting the possibility of microbial life on the Red Planet roughly between three-and-a-half and four billion years ago.

Mission project scientist John P. Grotzinger of CaTech said that the rover has found the evidence of life at Gale Crater as the region indicates the presence of rivers, lakes and deltas that is believed to have existed for tens of millions of years.

Grotzinger further said that even after the surface water underwent evaporation, a good amount remained under the surface.

The Curiosity rover took a year to reach Gale Crater after making its landing on Martian surface near Mount Sharp.

According to the NASA scientists, the Mars rover has also found the presence of simple organic compounds on the planet’s surface. The scientists said that this is another sign of past habitability.

The team members of the mission project will be presenting the new revelations about these compounds and geological and chemical evidence for the past habitability on Mars at a meeting of the American Geophysical Union (AGU), which is scheduled for December 14.

According to the scientists, there are several factors that must be present in a world for supporting even the simplest life. These factors include liquid water; a significant span of time for life to evolve; a source of energy and the presence of oxygen, carbon, hydrogen, nitrogen and phosphorus.

In its two years of journey on the Martian surface, Curiosity has found crucial evidence about the presence of water in several locations and at various times in its past on the Red planet. The rover had also detected the five mentioned elements and an energy source.

NASA said that the remains of lakes and other water bodies have also been confirmed by orbiting satellites.