New evidence of a colder far side mantle
A Chinese-led team has reported a groundbreaking discovery about the Moon: the mantle beneath the far side is colder than the near side. The finding, published in Nature Geoscience on September 30, comes from meticulous analysis of lunar dust samples retrieved by the Chang’e 6 mission, a landmark for lunar science and international curiosity about Earth’s celestial neighbor.
Why the hemispheric difference matters
The Moon’s near side and far side differ in crustal thickness, volcanic history, and the distribution of heat-producing elements. Understanding why the mantle temperatures diverge helps scientists reconstruct the Moon’s thermal evolution and the processes that yielded its current hemispheric dichotomy. This work provides crucial petrological and geochemical data to explain how the Moon evolved differently across hemispheres.
Where the data came from and how it was analyzed
Researchers combined several independent methods to characterize the samples. They examined typical minerals such as clinopyroxene and plagioclase within the lunar regolith basalt, using three thermobarometers to estimate crystallization temperatures and pressures. To validate results, a petrological model simulated the crystallization of the Chang’e 6 samples. The team also cross-checked their findings with lunar remote-sensing data to extend the analysis beyond the lab.
The key finding: a roughly 100 C difference
Across the different analytical approaches, the results converged: the crystallization temperature of the basalt from the far side was about 1,100 C, roughly 100 C lower than near-side samples. By reconstructing the original magma’s chemistry and calculating mantle temperatures, the researchers concluded that the far side mantle’s potential temperature sits about 100 C lower than the near side. This thermal asymmetry aligns with observed crustal thickness variations and the distribution of heat-producing elements across the Moon.
Methodology and collaboration
The study underscores the value of cross-disciplinary collaboration between nuclear science and space research. Institutions involved include the Beijing Research Institute of Uranium Geology, a subsidiary of China National Nuclear Corp, along with Peking University and Shandong University, under the umbrella of the China National Space Administration and the China Atomic Energy Authority. This teamwork echoes previous breakthroughs, such as the discovery of the Changesite-(Y) mineral in 2022, highlighting China’s growing role in planetary science.
Why this matters for lunar evolution and future missions
By establishing a concrete temperature difference between the Moon’s hemispheres, scientists gain insight into the internal structure and evolutionary timeline of our natural satellite. The findings offer constraints on models of thermal evolution, crust formation, and the distribution of geochemical reservoirs. As sample-return missions continue to unlock new data, researchers can refine their understanding of how internal heat drove volcanic activity and crustal growth on the Moon.
Chang’e 6: advancing access to the far side
Chang’e 6 marked a historic step as the world’s first mission to return samples from the Moon’s far side. Launched from Wenchang in May 2024, the mission completed complex operations over 53 days and delivered 1,935.3 grams of lunar material. The new study uses these samples to illuminate the Moon’s interior and to prepare for future exploration, including potential human missions that may rely on a deeper grasp of thermal patterns and resource distribution.
Implications for Earth’s understanding and future exploration
Beyond lunar history, studying the Moon’s hemispheric asymmetry offers broader insights into planetary formation and thermal evolution. Differences in mantle temperature can reveal how internal heat shapes crustal features, volcanic histories, and the evolution of airless bodies in our solar system. As researchers continue to synthesize laboratory results with remote sensing, the story of the Moon’s interior becomes clearer, guiding both science and exploration priorities for years to come.
