Mars lakes and streams once flowed billions of years ago

12 Oct 2015

An artist’s impression of Mars 4bn years ago. Image via ESO

When it comes to water on Mars stories, it appears that when it rains it pours as new findings have shown that, billions of years ago, the Martian surface could sustain flowing lakes and rivers.

Last month was a particularly exciting time for astronomers, and the general public alike, after the existence of flowing (albeit minute amounts)  of water near Mars’s northern polar region was confirmed.

And not even a few days later, an Irish-led team discovered similar water flows beneath Martian glaciers that are occurring at this very moment.

But now, a new research paper published in Science has dialled it back a bit to between 3.3bn and 3.8bn years ago to reveal that the planet’s surface could indeed have seen the existence of deep lakes and streams.

The team from the Mars Science Laboratory (MSL) has found evidence that the planet’s atmosphere was considerably larger during this time, which would have been capable of supporting a hydrosphere.

In particular, the site where the Curiosity rover is now operating at the Gale Crater was originally one of these deep lakes with evidence shown as the large sediment deposits that make up much of the crater’s surface.

Mars lakes

Image from the base of Mount Sharp. Image via NASA/JPL-Caltech

One such massive deposit that Curiosity reached the foothills of in September 2014 was Mount Sharp, however, these findings now contradict previous ancient climate models for the planet, which would have suggested it was too cold for water to exist in its liquid form.

Speaking of the discovery, co-author of the paper, Woody Fisher, said it shares close similarities with Earth: “This is exactly what we see in rocks that represent ancient lakes on Earth. The mudstone indicates the presence of bodies of standing water in the form of lakes that remained for long periods of time, possibly repeatedly expanding and contracting during hundreds to millions of years.”

Of course, the question now turns to the possibility of discovering the existence – past or present – of life on Mars, but lead author of the paper, John Grotzinger, says the search for more data goes on.

“We have tended to think of Mars as being simple,” he says. “We once thought of the earth as being simple, too. But the more you look into it, questions come up because you’re beginning to fathom the real complexity of what we see on Mars. This is a good time to go back to re-evaluate all our assumptions. Something is missing somewhere.”

Colm Gorey was a senior journalist with Silicon Republic