China’s Mars rover finds signs of recent water in the dunes

CAPE CANAVERAL, Fla. (AP) – Water may be more widespread and recent on Mars than previously thought, based on observations of Martian sand dunes by a Chinese rover.

The result highlights new, potentially fertile areas in the warmer regions of Mars where conditions may be suitable for life, although further study is needed.

Friday’s news comes days after mission leaders acknowledged that the Zhurong rover has yet to wake up since entering Martian hibernation nearly a year ago.

Its solar panels will likely be covered in dust, choking its power source and possibly preventing the rover from operating again, said Zhang Rongqiao, the mission’s chief designer.

Before Zhurong fell silent, he saw rich salt dunes with cracks and crusts, which the researchers said were probably mixed with morning frost or snow as recently as a few hundred thousand years ago.

An estimated date range for when the cracks and other dune features were created in Mars’ Utopia Planitia, a large plain in the northern hemisphere: sometime after 1.4 million to 400,000 years ago or even younger.

Conditions during that period were similar to today on Mars, with rivers and lakes drying up and no longer flowing as they had done billions of years before.

Studying the structure and chemical composition of these dunes can provide insights into the “possibility of water activity” during this period, the Beijing-based team wrote in a study published in Science Advances.

“We think it could be a small size … no more than a film of water on the surface,” co-author Xiaoguang Qin of the Institute of Geology and Geophysics said in an email.

The rover did not directly detect any water in the form of frost or ice. But Qin said that computer simulations and observations from other spacecraft on Mars show that conditions may be suitable for water to be visible even today at certain times of the year.

What’s remarkable about the study is how young the dunes are, said planetary scientist Frederic Schmidt of the University of Paris-Saclay, who was not part of the study.

“This is clearly a new piece of science for this region,” he said in an email.

Small cracks, hard crusty surfaces, loose particles and other dune features such as depressions and ridges were likely the result of small pockets of water from melting frost or snow, mixed with salt, the Chinese scientists said. They ruled out wind as a cause, as well as frost made from carbon dioxide, which makes up most of Mars’ atmosphere.

Martian frost was observed by NASA’s Viking missions in the 1970s, but these light dustings of morning frost were thought to occur in certain locations under specific conditions.

“The rover has now provided evidence that this process may be more widely distributed on Mars than previously recognized,” said Mary Bourke of Trinity College, Dublin, an expert on Martian geology.

However small this aquatic niche is, it could be important for identifying habitable environments, she said.

Launched in 2020, the six-wheeled Zhurong – named after the god of fire in Chinese mythology – reached Mars in 2021 and spent a year wandering around before entering winter last May. The rover performed longer than planned, traveling more than a mile (1,921 meters).

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AP video producer Olivia Zhang in Beijing contributed to this report.

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The Associated Press Health and Science Section is supported by the Howard Hughes Medical Institute Science and Media Education Group. The AP is solely responsible for all matters.

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