Examining data from China’s Zhurong rover, scientists have found cracks in tiny Martian dunes for the first time, suggesting that the Red Planet was a salt-rich water world as early as 400,000 years ago. from the moment landing In May 2021, in the northern hemisphere of Mars, the rover approached the four closest planets. sand hill To investigate the composition of crescent-shaped surfaces in the Utopia Planitia region. According to the new articleAll four wind-formed miniature geological features are covered with thin, widely eroded crusts and ridges formed by the melting of small pockets of “modern water” somewhere between 1.4 million years and 400,000 years ago.(opens in new tab)published Friday (April 28) .

“This marks a later time in Martian history,” Xiaoguang Qin, a scientist at the Chinese Academy of Sciences in Beijing and author of the new study, told Space.com.

Scientists have long known that it was early, about three billion years ago. Marcy had plenty of liquid water. But drastic climate change has frozen much of the planet, as ice has now accumulated at the poles and much of the planet has been scorched.

The dunes that Zhurong examined near the landing site in the planet’s northern hemisphere—far from the north pole—are 50 to 100 feet (15 to 30 meters) long and about 3 feet (1 m) high. Recent findings from analysis of images and data sent home by Zhurong and the orbiter Tianwen 1 shows that a few million years ago, substantial water from the planet’s icy polar regions percolated into lower latitudes and settled on the sand dunes of Utopia Planitia.

When Zhurong dares to approach the target dunes, which are about the size of a pint compared to NASA’s massive two-deck Curiosity rover, researched Elsewhere on Mars, the rover’s Laser Refraction Spectrometer (MarSCoDe) instrument has split sand grains into millimeter sizes. particles Their chemistry revealed hydrated minerals such as sulfates, silica, iron oxide and chlorides. According to the research team, these minerals formed in the presence of water at low latitudes during the late Amazonian period on Mars, which scientists previously thought was dry.

The researchers say water vapor traveled from the Martian poles to lower latitudes a few million years ago, such as Zhurong Point, where the planet’s polar ice caps released large amounts of water vapor due to a different tilt that caused the Martian poles to point more directly. opposite Sun. According to a recent study, the cold temperatures on the oscillating planet condensed the entrained vapor and discharged it as snow away from the poles.

Qin told Space.com that the tilt of Mars changes over a 124,000-year cycle, so “this points to the atmospheric steam supply mechanism to create frost or snow at low latitudes where the Zhurong rover landed.” However, “No instruments on the Zhurong rover detected water ice.”

Instead, just as road salting on Earth melts chunks of ice during storms, salts on the Martian sand dunes warmed the falling snow and dissolved it enough to form salt water. The process also produced minerals like silica and iron oxide, which the researchers said Jurong had detected.

But the brine did not stay for long. Temperature on Mars, according to research According to the study, between 5 and 6 a.m. it fluctuates wildly and rises sharply, so the brine evaporated, leaving behind salt and other newly formed minerals; these then infiltrated between the sand grains of the dune, cementing them and forming a crust.

The crust that formed on the dunes at a depth of 0.5 inches (1.25 centimeters) to 3 inches (1.7 cm) probably occurred a year later because the loose sand dunes did not stay in place long enough to solidify over thousands of years. Later, the high temperatures dehydrated it so much that it “must be tough and resist wind erosion,” Qin said.

“This phenomenon has been documented somewhere, but it should apply to a sizable portion of the Martian surface at similar latitudes,” said Manasvi Lingam, associate professor of astrobiology at the Florida Institute of Technology. to work. research, reports Space.com. Since Zhurong, who is currently drowning under powder coated solar cells Researchers of the new study, who found water activity above and in salty Martian dunes, suggest future missions, perhaps to search for salt-tolerant microbes such as resident brine shrimp or brine shrimp. In the Great Salt Lake in the US state of Utah.