New evidence of rippling water on Mars could change our understanding of the planet's history.

Planetary astronomers and geologists studying Mars have known for decades that water was once present on the planet. The Red Planet is now known as a dusty and cold world, but billions of years ago water flowed on the planet’s surface.

Its atmosphere thinned over time, causing water to evaporate. Scientists believe this was likely due to the planet losing its magnetic field which left it vulnerable to solar radiation, causing the planet’s water to evaporate into space.

The new discovery adds further context to the ongoing debate about the form Martian water took and how long it lasted. Some models suggest that any liquid water on the Martian surface would have been covered by sheets of ice before it vanished into the atmosphere.

However, the new findings suggest a different scenario that is very exciting as the search for alien life continues. Pictures taken by NASA’s Curiosity rover show patterns known as wave ripples. They’re small structures that resemble ridges that form along the shores of lakebeds, suggesting that liquid water must have flowed across the planet’s surface at some point in its history.

The ripples were found in two separate lakebeds in Gale Crater, which Curiosity has been exploring since August 2012. Both dry lakebeds likely formed around 3.7 billion years ago, suggesting that the Martian atmosphere was both dense and warm enough to support liquid water for much longer than previously thought.

Why is this so exciting? Because life as we know it needs water to thrive and evolve and its therefore a key component in searching for evidence of ancient life on Mars. If living organisms were ever present on Mars, the new findings indicate they had a longer window in which they could have evolved.

The study’s first author, sedimentologist at CalTech, Claire Mondro, said: "Extending the length of time that liquid water was present extends the possibilities for microbial habitability later into Mars's history.”

Mondro added: “The shape of the ripples could only have been formed under water that was open to the atmosphere and acted upon by wind.”

The study was published in the journal Science Advances.

Scientists recently discovered more about the origins of Marsquakes and NASA’s Curiosity rover snapped pictures of iridescent twilight clouds in the Martian sky.