The clearest evidence of a watery past on Mars has been discovered by the Mars rover Opportunity, a Martian rover which has been in operation since 2004.
The rover discovered, and examined, a rock in an area referred to as "Cape York" which dates back to era when water on Mars would have been plentiful and capable of supporting life.
The rock in question is rich in a variety of clay minerals, ranging from aluminum to calcium, and, according to a Friday statement by NASA, likely formed thanks to neutral water - water that, as one NASA scientist put it, "you could drink."
Scientists named the rock "Esperance," and is one of the oldest rocks Opportunity has happened across during its nine-year journey.
"The Esperance results are some of the most important findings of our entire mission," Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the mission said in a prepared statement. "The composition tells us about the environmental conditions that altered the minerals. A lot of water moved through this rock."
While this isn't the first sign that water once flowed on Mars, it is the first discovery of water which could have supported life. Other discoveries, The New York Times reports, pointed towards water so acidic that it may have been sulfuric acid.
The news is certainly exciting, it doesn't mean that life once existed on the barren red planet, nor does it mean that Opportunity will find evidence of life anytime soon. The rover Opportunity, according to The New York Times, isn't equipped with the right instruments capable of detecting a particular set of carbon molecules which would suggest life.
But Opportunity, which is still operating with ease, could find more evidence as the rover explores Solander Point. That point, according to NASA, contains a tall stack of geological layering, allowing the rover to peer deeper into the red planet's past.
Curiosity, as The New York Times also reports, is moving towards its prime goal: an 18,000-foot mountain which, NASA believes, is also a prime location to discover more Martian clay.
Opportunity has far surpassed the rover's original 90-day lifespan planned by NASA. During its time on the Martian surface, the rover has explored six craters, travelled over 11 miles, photographed Martian clouds and survived Martian dust storms. It launched with a sister rover, named Spirit, in 2003. Spirit, like Opportunity, far surpassed its planned lifespan, but became immobile in 2009 and had to shut down in 2010.
