Earlier this week, scientists on NASA's Curiosity rover team announced that they'd discovered signs of an area that, billions of years ago, was a freshwater lake - that may have been able to sustain life.
"Our mission is turning a corner," Curiosity project scientist John Grotzinger told ScienceNow. "We are beginning to map a way forward, a way to explore deliberately for organic matter."
The lake was located in what is called Yellowknife Bay. Last year, a rock sample examined by Curiosity in that area was shown to have been composed of clays that could have been suitable for life. In the months that followed, scientists have learned even more about it.
What's interesting about the new finds is that they seem to indicate that there was a substantial amount of organic matter in the clays. Although there's no sign of life just yet (Curiosity doesn't have the equipment to make that final determination).
According to the evidence that Curiosity has been able to uncover so far, the habitable conditions on ancient Mars persisted for millions - if not tens of millions - of years, as lakes and rivers rose and subsided, building clay sediments similar to those here on Earth. And those sediments created conditions that microbial life forms on Earth survive and thrive in today.
The site where Mars may have been habitable is also younger than previously thought - sticking around even in the early years of Mars' climate change to the arid desert that it is today. As a result, it's possible that more parts of Mars were habitable for longer than was previously thought. And they were habitable at a time when life was beginning here on Earth.
"This habitable environment existed later than many people thought there would be one," Grotzinger said in a press release. "This has global implications. It's from a time when there were deltas, alluvial fans and other signs of surface water at many places on Mars, but those were considered too young, or too short-lived, to have formed clay minerals. The thinking was, if they had clay minerals, those must have washed in from older deposits. Now, we know the clay minerals could be produced later, and that gives us many locations that may have had habitable environments, too."
The existence of more and larger habitable areas on Mars gives future Mars missions that many more places to look for signs of life, and makes it more likely that those missions could find some, if the conditions were right for life to emerge on Mars in the first place. It'll be fascinating to see what those future missions are able to uncover.
