Chinese scientists discovered that the lunar mantle on the far side of the moon is colder than the near side. This finding sheds light on differences in the moon’s mantle and its hemispheric asymmetry.
A joint team from the China National Space Administration, China Atomic Energy Authority, Beijing Research Institute of Uranium Geology, Peking University, and Shandong University conducted the study. They analyzed samples returned by China’s Chang’e 6 mission, the first to collect material from the moon’s far side.
The Chang’e 6 mission launched in May 2024 from the Wenchang Space Launch Center in Hainan province. After 53 days of complex maneuvers, it returned 1,935.3 grams of lunar samples. Scientists used these samples to study the lunar mantle and the internal composition of the moon.
Using multiple methods, the team examined minerals including clinopyroxene and plagioclase in the lunar regolith basalt. They calculated crystallization temperatures and pressures with three thermobarometers. They also simulated the crystallization process using petrological models. All four methods consistently revealed information about the lunar mantle.
The analyses showed that basalt samples from the far side crystallized at about 1,100 degrees Celsius. This is roughly 100 degrees lower than samples from the near side. The reconstructed chemical composition of the moon’s original magma confirmed that the far side mantle is also about 100 degrees cooler. Lunar remote sensing data verified these findings on a broader scale.
Li Ziying, a senior scientist and research leader, explained that studying differences in the lunar mantle between the near and far sides improves understanding of lunar formation. Insights from the moon’s mantle also inform Earth’s evolution and planetary asymmetry.
The research highlights the success of China’s cross-disciplinary collaboration between nuclear and space scientists. Their previous achievements include discovering the sixth lunar mineral, Changesite-(Y), in late 2022. Findings from Chang’e 6 provide petrological and geochemical evidence to guide future lunar mantle research and exploration.
Overall, the discovery confirms that the lunar mantle on the far side is colder. This aligns with differences in crust thickness and heat-producing element distribution. Scientists believe this research will support studies of lunar thermal evolution and hemispheric dichotomy.
