Chang’e-6 Moon Mission Uncovers Secret Hidden for Billions of Years

The data suggests a dynamic and geologically active lunar interior, possibly driven by magma oceans or core processes. This landmark study was published in the journal Nature.

Understanding the evolution of the lunar dynamo is key to unraveling the Moon’s deep interior structure, thermal history, and surface environment. Recent research by Chinese scientists, analyzing basalts brought back by the Chang’e-6 mission, uncovered a major resurgence in the lunar dynamo’s strength around 2.8 billion years ago (Ga).

While earlier paleomagnetic studies of nearside lunar samples provided a general timeline for the Moon’s magnetic field evolution, the lack of comprehensive spatial and temporal data has made the full history of the lunar dynamo uncertain.

The Chang’e-6 mission, which returned the first farside basalt samples dated to approximately 2.8 Ga, provides a unique opportunity to fill this critical gap in our understanding of the lunar dynamo’s spatiotemporal evolution.

Led by Prof. Rixiang Zhu at the Institute of Geology and Geophysics of the Chinese Academy of Sciences (CAS), Associate Professor Shuhui Cai and her colleagues measured the ancient magnetic field strength from the Chang’e-6 basalts, obtaining values ranging from approximately 5 to 21 microteslas (µT).

These findings revealed an unexpected resurgence in field strength at 2.8 Ga, following a sharp decline around 3.1 Ga. This challenges the prevailing hypothesis that the lunar dynamo entered a low-energy state after 3 Ga and remained in this condition until its cessation.

The researchers proposed that the lunar magnetic field during this period may have been driven by a basal magma ocean and/or powered by precessional forces. Additional mechanisms, such as core crystallization, may have also a role.

These findings suggest that the Moon’s deep interior remained hot and geologically active well into its mid-early history.

This study represents the first-ever paleomagnetic data obtained from the Moon’s farside, providing critical insights into the intermediate stages of the lunar dynamo’s evolution. By synthesizing this data with existing findings, the researchers suggested significant fluctuations in the lunar magnetic field between 3.5 and 2.8 Ga, indicating a highly unstable dynamo during this period.

These results offer valuable guidance for future lunar exploration missions, including the search for potential magnetic reversals.

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