Rover finds ‘evidence of ancient floods’ on Mars

The first Chinese rover to explore Mars may have found evidence of two epic floods that would have submerged part of the planet under water more than 1.6 billion years ago.

The Zhurong rover landed last year in a large crater known as Utopia Planitia in the northern Martian hemisphere, widely believed to have been the site of an ancient ocean. However, scientists have not gathered data from the surface there for 45 years, since the United States Viking-2 mission.

Zhurong is equipped with a ground-penetrating radar system, capable of providing clues on what lies beneath the planet’s surface, to a depth of around 80m.

The latest results, published in the science journal Nature this week, picked out two geological layers. The oldest appears to have been the result of a flood that carried sediment to the area more than three billion years ago. Another layer, closer to the surface, may have been created by another flood some 1.6 billion years ago.

That Mars, now an arid planet, was once a much wetter place was already known. In 2004, Nasa’s Opportunity rover found evidence that the planet was once awash with liquid water, indicating that life could once have existed there.

The Nasa rover Perseverance is exploring the Jezero Crater, just north of the Martian equator, which is thought to have been the site of a river delta some 3.5 billion years ago.

Earlier this month, Nasa said rock samples gathered by Perseverance contained ‘‘intriguing organic compounds’’ which may be the remnants of ancient Martian microbes.

Perseverance is collecting small samples of mud and stone, to be returned to Earth in 2033 for more sophisticated analysis.