China's Chang'e-6 Mission Reveals Secrets of Moon's Far Side

BEIJING, July 10, 2025 — Recent research conducted by Chinese scientists on samples collected from the moon's far side by the Chang'e-6 mission has provided unprecedented insights into the evolutionary history of this mysterious region. The findings, which include evidence of volcanic activity, ancient magnetic fields, and geochemical characteristics of the moon's mantle, were published in a series of four studies in the latest issue of *Nature*.

The Chang'e-6 mission, launched in December 2024, marked a significant milestone by retrieving 1,935.3 grams of lunar samples from the South Pole-Aitken (SPA) Basin, the largest, deepest, and oldest impact basin on the moon. This area, measuring approximately 2,500 kilometers in diameter, has long intrigued scientists due to its unique geological features. According to Wu Fuyuan, an academician at the Chinese Academy of Sciences (CAS), the energy released from the impact that formed the SPA Basin is estimated to be equivalent to one trillion times that of an atomic bomb explosion. However, the exact effects of this massive event on the moon's geological evolution have remained largely unsolved until now.

The research teams from the Institute of Geology and Geophysics (IGG) and the National Astronomical Observatories (NAO) of CAS, along with Nanjing University and other institutions, have uncovered significant evidence of volcanic activity on the moon's far side dating back approximately 4.2 billion and 2.8 billion years. This discovery indicates that such activity persisted for at least 1.4 billion years. Furthermore, the studies revealed that the water content in the lunar far-side mantle is significantly lower than that found on the near side, suggesting a stark contrast in water distribution between the two hemispheres.

"We found that the mantle source of basalt from the SPA Basin is extremely depleted in incompatible elements, which are essential for understanding the geological processes that rocks have undergone," said Yang Wei, a researcher at IGG. This depletion raises questions about whether the original lunar mantle was inherently low in these elements or if the impacts caused by significant collisions had removed them.

Li Chunlai, a researcher at NAO and deputy chief designer of the Chang'e-6 mission, emphasized the importance of these findings, stating, "This discovery marks humanity's first direct access to key evidence of the deep interior material properties on the moon's far side. It provides us with unique information to understand how the moon's early interior became layered, cooled, and evolved."

The four studies not only address the geological characteristics of the samples but also offer a timeline for the formation of the SPA Basin, now estimated to have occurred 4.25 billion years ago. This new anchor point is crucial for understanding the history of large-scale impacts during the early solar system.

International experts have highlighted the significance of these findings. Mahesh Anand, a professor at the Open University in the UK, remarked, "We have had samples from the moon for over 50 years, but the results from the Chang'e-6 samples are turning many well-established hypotheses in lunar science upside down, necessitating a reexamination of many theories."

The Chang'e-6 mission's success is a testament to the robust collaboration between science and engineering within China's space exploration program. He Hongping, vice president of CAS, noted that the organization has prioritized research efforts related to the lunar samples since their arrival, resulting in a series of high-level research achievements.

Guan Feng, director of the Lunar Exploration and Space Engineering Center of the China National Space Administration, expressed optimism for future developments in space science, technology, and applications. He urged the scientific community to leverage the extraterrestrial samples and data obtained from China’s lunar initiatives to drive further discoveries.

As the Chang'e-6 mission continues to reshape our understanding of the moon's geological history, it stands as a remarkable achievement in the ongoing exploration of our celestial neighbor. With the successful retrieval of far-side samples, researchers are poised to unravel the long-standing mysteries of the moon, offering new perspectives on its evolution and the broader history of our solar system.