The Curiosity rover uncovers evidence that Mars once had a massive lake

The Mars we know today is a frozen wasteland that endures deadly bombardments of cosmic and solar radiation every single day. But the Mars of the past may have been dramatically different.

Curiosity, the NASA rover that landed on Mars in 2012, has found new evidence suggesting the Red Planet once had lakes, rivers and even oceans.

“What they’ve found is a hint that Mars was habitable at one point in time.” says Tariq Malik, the managing editor of Space.com. “This new discovery suggests that [conditions for life] were stretched out not only over a few million years, but for tens and tens of millions of years. Life could have flourished in a wet, warm environment on Mars.”

You've probably already heard statements like that on the news in years past, but Malik says scientists have never seen evidence like this before.

Curiosity, which functions as a sort of mobile laboratory, detected a 96-mile depression that formed more than 3.5 billion years ago when a meteorite slammed into the planet. The evidence it collected suggests that the huge crater might have once held a lake, and that aquatic sediment from that lake has transformed over time into a mountain 18,000 feet tall.

“It’s called Mount Sharp and it rises three miles up from the floor of this crater,” Malik says. “What they had hoped to see when they got [to the mountain] were different sediment layers all the way up that would tell the story of this crater over the 3 billion years or so that it’s been around. And that’s what they’re seeing now.”

Though the idea of Mars as a wet planet seems more closely tied to a science fiction novel than it does reality, Malik says scientists plan to study the sediment layers to get a better picture of how the planet’s climate and environment changed over time.

“That’s what they’re looking at: They want to see the evolution of this lake in the crater,” he says. “They want to see how full it got, when it might have dried out to allow the winds to sculpt a three-mile mountain at its core, and then where that water went. … It’s perplexing to them right now.”

Malik points out that NASA’s findings are only the beginning. The evidence uncovered by Curiosity and the theories scientists are pursuing have yet to be published in scientific journals. But Curiosity is equipped with a series of high-powered instruments, including microscope cameras and lasers to break through rock.

“Curiosity has only been on Mars for two years and only at the base of this crater for the last few months,” he says. “They’ve got a big job ahead of them because they want to actually climb that mountain with the rover to get even deeper into this story.”

In addition to learning more about the planet’s environment and geological history, many are hoping that Curiosity might find some concrete signs of life.

“There’s always the possibility,” says Malik. “Water on Earth is one of the cornerstones of life, so that’s kind of the going theory for scientists exploring Mars — if they find the water, there’s a chance that there could be life there. That’s kind of like the Holy Grail."

This story is based on an interview from PRI's The Takeaway, a public radio program that invites you to be part of the American conversation.