There is growing evidence that Mars, now cold and dry, had liquid water flowing over its surface much more recently than previously thought.
Scientists have long believed that March was wet about 3 billion years ago, during the planet’s Hesperian period, and then lost much of its water. But a new study presents evidence of water activity just 700 million years ago, well into the current Amazon period, posing a new puzzle to solve about the Red Planet and its history.
The new study is based on data from China’s Zhurong rover, which is part of the Tianwen-1 mission and landed on the surface of Mars in May 2021. In particular, the scientists used data the rover collected during its first 92 Martian days, or sols, at its landing site in Utopia Planitia. Yang Liu, a researcher at the National Space Science Center (NSSC) of the Chinese Academy of Sciences (CAS), and his colleagues analyzed data from three different instruments on Zhurong: the laser-induced breakdown spectrometer (MarSCoDe), the telescopic microimaging camera and the short wave infrared spectrometer.
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These instruments studied minerals that the team say suggest the presence of a substantial amount of liquid water at the site around 700 million years ago, well before present-day Amazon times, which scientists believed. previously dry.
“This is a very interesting result,” says Eva Scheller, a planetary scientist at the California Institute of Technology who was not involved in the new research. “We have very little recorded evidence of ‘young’ liquid water systems on Mars. And for those we do have, they were usually in the form of salty minerals.”
But Zhurong’s instruments spotted water molecules locked in the rock, “which is very interesting and different from other young liquid water environments that have been observed,” Scheller said. “This means that particular forms of aquifer minerals would have formed at much later times than previously assumed in other scientific studies.”
NASA has sent its Mars rovers to ancient landing sites, dating to the Noachian age more than 3.7 billion years ago. Zhurong is therefore not just another set of wheels on Mars, but a powerful suite of instruments exploring a new, geologically young site to open up new windows of opportunity for Mars research.
“One of the main things we’ll need to find out that I’m looking forward to seeing from the Zhurong rover is the extent of these ‘young’ aquifer minerals,” Scheller said. “Are they common or uncommon in these ‘young’ rocks?”
Zhurong has now covered about 1.24 miles (2 kilometers) in his more than 350 Martian days and analyzed a range of features on his travels, which means new Martian information is still expected to come from the rover.
The results are described in a document published Wednesday, May 11 in the journal Science Advances.
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