Mars may have had liquid water more recently than thought, Chinese rover study suggests

China’s Zhurong Mars rover has found evidence that the Red Planet may have had liquid water hundreds of millions of years more recently than previously thought.

While previous research has suggested Mars was wet about 3 billion years ago and then lost its water, the new study, published in the journal Science Advances on Wednesday, suggests the Red Planet may have had water activity just 700 million years ago.

Although studies have suggested ancient Mars was a wet and habitable planet, the most recent epoch of Mars’s geologic history, Amazonian, is often thought to be cold and dry.

In the latest study, scientists, including those from the Chinese Academy of Sciences in Beijing, assessed data from the rover that landed in the southern Utopia Planitia region on Mars.

They assessed the data from three different chemical analysis instruments aboard the rover – a laser-induced breakdown spectrometer (MarSCoDe), a telescopic microimaging camera, and a short-wave infrared spectrometer.

Based on the analysis, researchers found evidence of “hydrated sulfate/silica materials” on the geologically young Amazonian terrain at the landing site.

The research suggests the area explored by the rover is made of a hard layer of soil, or duricrust, with different characteristics compared to rocks seen at other locations on Mars that may have risen from salty groundwater, slowly evaporating, and cementing the duricrust.

These minerals, researchers say, were likely formed with substantial liquid water originating from either “groundwater rising or subsurface ice melting”.

“In situ evidence for aqueous activities identified at Zhurong’s landing site indicates a more active Amazonian hydrosphere for Mars than previously thought,” researchers wrote in the study.

Scientists say a better understanding of how recently Mars had liquid water can also help estimate how much water may remain on the Red Planet in ice or mineral form.

Based on the findings, researchers also speculate Mars may have gone through cycles of climate, changing from wet to warm, and dry to cold, instead of undergoing a single dramatic shift.

“The Zhurong landing site (and the northern lowlands) may contain a considerable amount of accessible water in the form of hydrated minerals and possibly ground ice for in situ resource utilisation for future human Mars exploration,” they added.

As part of its primary mission to look for signs of life on Mars that lasted for three months, Zhurong has investigated the minerals, landscape, and distribution of water and ice in the Utopia Planitia region.

So far, the rover has covered about 2km (1.24 miles) in over 350 Martian days, meaning more insights into the Red Planet are still likely to come from its missions.

In another study published on Wednesday in the same journal, scientists assessed a meteorite from Mars that was discovered in the Miller Range of mountains in Antarctica in 2003.

This research found that while water may have once shaped the rock inside the meteorite, it likely did not support any forms of life.

Researchers, including those from Lund University in Sweden, found minerals within the meteorite likely altered by liquid water in isolated patches – a pattern indicating the water likely came from ice buried within the rock itself and not from a hydrothermal system.

The study suggests the martian crust sampled by the meteorite “could not have provided habitable environments that could harbor any life on Mars during the Amazonian.”

However, scientists said these findings applied only to this section of the Red Planet where the meteorite rock may have originated from, and not to Mars as a whole.