At one point in history, long ago, Mars likely had numerous large lakes on its surface, according to new Curiosity rover data.

Since Curiosity reached Mount Sharp at the center of Mars' Gale Crater, the rover's main destination, the updates from the Red Planet have slowed. But that is not to say there is nothing new to report.

According to the Washington Post, the latest development from Curiosity's on-board science lab supports a popular theory about Mars while shooting down another. The rover's previous discoveries have supported the theory that Mars once could have sustained water, but now it appears as though the water was not underground, like scientists previously believed.

"If our hypothesis for Mount Sharp holds up, it challenges the notion that warm and wet conditions were transient, local, or only underground on Mars," Ashwin Vasavada, Curiosity deputy project scientist at NASA's Jet Propulsion Laboratory (JPL), said in a press release. "A more radical explanation is that Mars' ancient, thicker atmosphere raised temperatures above freezing globally, but so far we don't know how the atmosphere did that."

Mount Sharp, which stretches three miles high, sits in the middle of the Gale Crater, Curiosity's landing site. Now that Curiosity has reached the mountain, NASA scientists are learning more and more of the planet's environmental history. They believe several lakes in the Gale Crater gave Mount Sharp its unique shape and layered composition, but the planet would have needed different atmospheric conditions.

"We are making headway in solving the mystery of Mount Sharp," John Grotzinger, Curiosity project scientist, said in the release. "Where there's now a mountain, there may have once been a series of lakes."

Mars' atmosphere would have had to have been thicker and warmer for there to have even been above-ground lakes, but NASA has a spacecraft orbiting the Red Planet to determine just that.

"The great thing about a lake that occurs repeatedly, over and over, is that each time it comes back it is another experiment to tell you how the environment works," Grotzinger said. "As Curiosity climbs higher on Mount Sharp, we will have a series of experiments to show patterns in how the atmosphere and the water and the sediments interact. We may see how the chemistry changed in the lakes over time. This is a hypothesis supported by what we have observed so far, providing a framework for testing in the coming year."