China's Chang'e-4 mission rover has helped scientists visualise hidden structures hundreds of metres deep below the surface of the moon's far side, revealing billions of years of lunar history. The Yutu-2 rover used its Lunar Penetrating Radar (LPR) to image deep into the moon's surface by listening to echoes of sound that bounced back off structures hidden from view.
The rover and lander made history in 2019 as the first human objects to land on the far side of the moon. Previous ground penetrating radar efforts could only map the top 40 metres, but the new discovery has found structures at depths of about 300 metres.
The data suggests the first 40 metres under the lunar surface is made up of layers of dust, soil, and rocks. Radar analysis also revealed a buried crater formed by a large impact and mapped ancient lava flows. Researchers found multiple layers in the upper 300 metres, likely indicating a series of basalt eruptions billions of years ago.
The study, published in the Journal of Geophysical Research: Planets, revealed that volcanic rock layers are thinner closer to the surface, suggesting a decrease in eruption scale over time. Scientists concluded that lunar volcanic activity cooled gradually since the moon's formation over 4.5 billion years ago.
