Moon’s magnetic pull lasted much longer than thought: Chinese study

Lunar rocks collected by China’s Chang’e-5 mission reveal new details that may offer key insights into planetary habitability and evolution

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Samples collected by China’s Chang’e-5 lunar mission have shown that the moon’s magnetic field lasted much longer than previously thought. Photo: Shutterstock

Published: 6:00pm, 4 Jan 2025

Chinese scientists have found direct evidence that the moon’s magnetic field persisted well into its midlife, long after it was thought to have disappeared.

Researchers analysing tiny rocks returned by China’s Chang’e-5 mission discovered that the moon’s magnetic field measured two to four microteslas around two billion years ago – less than 10 per cent of Earth’s present-day surface field. They published their findings in the Science Advances journal on Thursday.

Ross Mitchell, co-author of the paper from the Institute of Geology and Geophysics in Beijing, said that while some believed the moon’s magnetic field had long vanished by then, their study showed it was “at least still limping along”.

The weak, but long-lasting, magnetic field was probably driven by enduring interior processes, such as the crystallisation of the moon’s core or the interactions between its core and mantle, according to planetary scientist Benjamin Weiss of the Massachusetts Institute of Technology, who was not involved in the study.

These processes would have kept the moon’s magnetic engine, known as the lunar dynamo, running for billions of years.

“The moon goddess’s elixir seems to have done the trick,” Weiss wrote in a review article interpreting the findings. He was referring to the Chang’e missions, which were named after the goddess who sought refuge on the moon after stealing an elixir of immortality from the gods.