Samples collected from the moon’s far side by China’s Chang’e-6 lunar probe have unveiled groundbreaking insights into the moon’s magnetic history, revealing a surprising resurgence in its magnetic field 2.8 billion years ago.
Published in the journal Nature on Thursday, the analysis shows that after a significant decline around 3.1 billion years ago, the moon’s magnetic field experienced an unexpected revival in strength. This challenges the prevailing theory that the lunar dynamo remained in a low-energy state following its earlier weakening.
These findings represent the first-ever paleomagnetic data obtained from the moon’s far side, illuminating intermediate stages of the lunar dynamo—a geophysical process that once generated the moon’s magnetic field.
On June 25, Chang’e-6 returned to Earth with 1,935.3 grams of samples from the moon’s far side, a previously unexplored region. Researchers from the Institute of Geology and Geophysics (IGG) under the Chinese Academy of Sciences analyzed four basalt fragments from the mission.
The team detected an increase in paleomagnetic field strength within these samples, suggesting a possible reactivation of the lunar dynamo after its initial decline. According to the study, this resurgence may have been caused by alterations in the dynamo’s energy sources or a revival of its driving forces.
Questions remain regarding the precise timeline, duration, and mechanisms driving the moon’s magnetic field, highlighting gaps in understanding the lunar far side. These new findings provide crucial clues to fill these gaps.
“Understanding the evolution of the lunar dynamo is of great significance for revealing the moon’s internal structure, thermal history, and surface environment,” said Cai Shuhui from the IGG, the corresponding author of the study.
A peer reviewer of the paper stated that the team’s “highly original results” fill a billion-year-long gap in the lunar paleomagnetic record and provide “the first paleomagnetic measurements from the lunar far side,” representing “a major advance in our understanding of lunar magnetism.”
These findings build on other major discoveries from Chang’e-6. In November, an IGG team reported two volcanic events on the moon’s far side, occurring 2.8 billion and 4.2 billion years ago, also published in the journal Nature.
Another study, published in the journal Science, confirmed that the low-titanium samples collected by Chang’e-6 are approximately 2.83 billion years old, offering further evidence of volcanic activity on the moon’s far side.
These groundbreaking discoveries from Chang’e-6 not only enhance our understanding of the moon’s magnetic history but also shed light on its geological evolution, providing invaluable information for future lunar exploration.
Reference(s):
Chang'e-6 moon samples unveils surprising magnetic field resurgence
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