Chinese lander discovers giant polygonal structures buried under Mars: ScienceAlert

China’s Zhurong spacecraft is equipped with a ground-penetrating radar system, allowing it to peer beneath the surface of Mars.

Researchers announced new results from scans of Zhurong’s landing site on Utopia Planitia, saying they identified irregular polygonal wedges located at a depth of about 35 meters throughout the robot’s flight.

Objects measure from centimeters to tens of metres. Scientists believe the buried polygons resulted from freeze-thaw cycles on Mars billions of years ago, but they could also be volcanic, the result of cooling lava flows.

The Zhurong spacecraft landed on Mars on May 15, 2021, making China the second country ever to successfully land on Mars.

The gentle rover, named after the Chinese god of fire, explored its landing site, sent back images (including a selfie with the lander, taken by a remote camera), studied the Martian terrain, and made measurements using its ground-penetrating radar (GPR) instrument. .

Zhurong’s initial mission life was three Earth months, but it operated successfully for just over one Earth year before entering a planned hibernation state. but, No news has been heard from the vehicle since May 2022.

Researchers from the Institute of Geology and Geophysics of the Chinese Academy of Sciences who worked with Zhurong’s data said GPR provides an important complement to orbital radar explorations from missions such as the European Space Agency’s Mars Express and China’s Tianwen-1 orbiter.

They said an in-situ GPR survey could provide important local details on shallow structures and their composition at a depth of about 100 meters along the rover’s path.

Map of Mars with Zhurong landing site — Topographic map of Utopia Planitia (A), showing the landing sites of the Zhurong rover, the Viking 2 lander, and the Perseverance rover. Four local areas (c–f) with polygonal terrain are marked with white boxes. (NASA/JPL/University of Arizona)

Utopia Planitia is a large plain within Utopia, and is the largest recognized impact basin on Mars (also in the solar system) with a diameter of about 3,300 km. In total, the vehicle traveled 1,921 meters during its lifetime.

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Researchers led by Li Zhang, wrote in their paper published in nature, The rover’s radar detected sixteen polygonal wedges at a distance of about 1.2 kilometers, indicating a broad distribution of similar terrain beneath Utopia Planitia.

These unearthed features were likely formed 3.7 to 2.9 billion years ago during the Late Hesperian and Early Amazonian times on Mars, “perhaps as the ancient wet environment ceased. The polygonal terrain was subsequently buried, with or without erosion.” Through subsequent geological processes.

Schematic diagram of four polygon formation models — Schematic model of the polygonal terrain formation process at the Zhurong landing site. A) Cracking caused by thermal shrinkage on the surface. b) fissures filled with water ice or soil materials, c) stabilization of late Hesperian-early Amazonian polygonal surface terranes, d) ancient polygonal terranes, with or without erosion, subsequently buried by deposition of covering materials in the Amazon. (Zhang et al.)

While polygonal-type terrain was seen across several regions of Mars from Many previous tasksThis is the first time that indications of buried polygons have appeared.

The buried polygonal terrain requires a cold environment that may be related to the freezing and thawing processes of water and ice in southern Utopia Planitia on early Mars, the researchers wrote.

“The possible presence of water and ice needed for the freezing and thawing process in the wedges may have come from moisture migration caused by cryogenic suction from the subsurface aquifer on Mars, snow falling from the air or vapor diffusion to deposit porous ice,” he explains.

Previous research from Zhurong radar data He noted that multiple floods during the same time frame created several layers beneath the surface of Utopia Planitia.

While the New doorr indicates that the most likely possible formation mechanisms would be soil shrinkage from wet sediments that have dried, producing clay cracks, however, shrinkage resulting from cooling of lava can also produce thermal contraction cracks.

In both cases, they note that a significant change in Mars’ climate was responsible for the formation of the polygon.

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“The subsurface structure with capping materials covering the buried ancient polygonal terrain suggests that there was a marked paleoclimatic shift at some point afterward,” the researchers wrote.

“The variation above and below a depth of about 35 meters represents a marked shift in water activity or thermal conditions in ancient Mars time, implying that there was climate perturbation at low to mid-latitudes.”

This article was originally published by The universe today. Read the Original article.