NASA's Curiosity Rover has uncovered evidence of an ancient Martian lake that could have supported life as known to us, over long periods of time, perhaps millions of years.
The freshwater lake probably existed according to estimates, around 3.7 billion years ago, researchers said, suggesting the presence of habitable environments on the Red Planet more recently than previously thought.
Curiosity lead scientist John Grotzinger, of the California Institute of Technology in Pasadena told space.com that it looked quite earth-like, there was an alluvial fan, being fed by streams that originated in mountains, that accumulated a body of water.
He added that probably was not unlike what happened during the last glacial maximum in the western US.
The lake once stretched over a small part of the 96-mile-wide Gale Crater, which the 1-ton Curiosity Rover is exploring since it touched down on the planet in August 2012.
The $2.5-billion mission's main task had been to determine whether Gale Crater could ever have supported microbial life, which it achieved in March, when it announced that a spot near Curiosity's landing site called Yellowknife Bay was indeed habitable billions of years ago.
According to Grotzinger, the clay materials at what would have been at the bottom of the lake show a moderate to neutral PH levels suggesting the lake did not have a lot of dissolved salt, but did have the chemical and minerals that would have allowed life to exist.
He added, the team thought that the climate may also have allowed snow and ice to form nearby.
Drilling and chemical sampling showed mudstone formed from clay on the Gale Crater lake bed was rich in carbon dioxide, nitrogen and oxygen.
The lake stretched an estimated 50 miles in length and five miles in width.
NASA had not found organic carbon molecules as yet, but according to experts this could be attributed to radiation levels on the Martian surface.
NASA geologist Jennifer Eigenbrode said, organic molecules near the surface could well have been broken apart by the radiation Mars received from the Sun.
She pointed out however, that it did not mean radiation levels would have been too high for life to exist there are several organisms on earth that lived quite happily in high radiation environments, but it did mean organic compounds would be harder to find.