In a groundbreaking development for lunar science, the Chang’e-6 mission has delivered unprecedented insights into the history of the moon’s magnetic field.

Rock samples collected from the moon's far side by China's Chang’e-6 lunar probe have revealed an unexpected resurgence in the moon's magnetic field strength 2.8 billion years ago.

This finding stands in stark contrast to earlier conclusions drawn from the US Apollo missions, which suggested the moon's magnetic field declined about 3.1 billion years ago and remained weak thereafter.

Published in the prestigious journal Nature, this is the first-ever paleomagnetic data obtained from the moon's far side.

The new analysis sheds light on intermediate evolutionary stages of the lunar dynamo—the geophysical mechanism responsible for generating the moon's magnetic field in ancient times.

As reported by Guangming Daily, the findings significantly expand our understanding of the moon’s geophysical history.

The Chang’e-6 lunar probe, which made its return journey to Earth on June 25, 2024, brought back 1,935.3 grams of lunar samples from the previously unexplored far side of the moon.

Cai Shuhui, a researcher from the Institute of Geology and Geophysics (IGG) at the Chinese Academy of Sciences and first author of the Nature article, explained the principles governing magnetic field generation.

On Earth, this is facilitated by the movement of conductive fluid in the planet's liquid outer core, forming a magnetic shield that protects life-essential elements such as the atmosphere and water from cosmic rays.

Historically, the Moon possessed a similar 'magnetic field generator' which became inactive.

Previous analyses from the Apollo missions indicated that the moon's magnetic generator was active between 4.2 billion and 3.5 billion years ago, decreasing sharply around 3.1 billion years ago.

Further decline occurred between 1.5 billion and 1 billion years ago, leading to the eventual cessation of the generator after a billion years ago.

The discovery from the Chang’e 6 mission involves samples with a primary eruption age of 2.8 billion years, offering a unique data set to examine the spatial and temporal evolution of the moon's magnetic field generator.

Researchers at the IGG found ancient magnetic field strengths higher than previously assumed, suggesting a rebound or reactivation of the lunar magnetic field around 2.8 billion years ago.

IGG’s analysis points to possibilities such as a change in the energy source of the moon's magnetic generator or reinforcement of its initial driving mechanism.

This research not only provides the first human-obtained information about the moon’s ancient magnetic field but also offers pivotal insights into lunar geophysical evolution, as highlighted by Guangming Daily.