Chinese rover reveals what lurks under the dark side of the moon

26 Feb 202011.73k Views

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Image: © Stan Tiberiu/Stock.adobe.com

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China’s Chang’e 4 lunar lander and Yutu-2 rover have used radar to see beneath the surface of the moon and reveal its hidden secrets.

China made history by becoming the first country to land a spacecraft on the far side of the moon, and now new data published to Science Advances reveals what is lurking beneath its surface.

After landing on the eastern floor of the Van Kármán crater near the Moon’s south pole on 3 January last year, Chang’e 4 (CE-4) deployed its Yutu-2 rover, which uses lunar penetrating radar (LPR) to open a window to an unexplored world.

“The subsurface at the CE-4 landing site is much more transparent to radio waves, and this qualitative observation suggests a totally different geological context for the two landing sites,” said the study’s author, Li Chunlai of the National Astronomical Observatories of the Chinese Academy of Sciences.

Li and his team used the LPR to send radio signals 40 metres deep into the surface of the moon. Using the high frequency channel of 500 MHz, the researchers were able to see three times deeper than the previous Chang’e 3 mission.

Diagram showing the make-up of the Moon's subsurface with lander and rover at the top.

The subsurface stratigraphy seen by Yutu-2 radar on the far side of the moon. Image: CLEP/CRAS/NAOC

An ‘unprecedented’ look

Su Yan, a corresponding author of the study, added: “Despite the good quality of the radar image along the rover route at the distance of about 106 metres, the complexity of the spatial distribution and shape of the radar features make identification of the geological structures and events that generated such features quite difficult.”

To get a better picture, the researchers combined radar images with tomographic data and quantitative analysis of the subsurface. This showed that the layer beneath the surface is made of highly porous granular materials embedding boulders of different sizes.

This is likely the result of meteors and space debris that struck the moon during its early formation. The impact site would eject material to other areas, creating a cratered surface atop a subsurface with varying layers.

Li said these findings offers an “unprecedented” look at the moon’s history and could teach us a great deal about its evolution over millions of years.

“This work shows the extensive use of the LPR could greatly improve our understanding of the history of lunar impact and volcanism and could shed new light on the comprehension of the geological evolution of the moon’s far side,” he said.

Colm Gorey is a senior journalist with Siliconrepublic.com

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