Moon’s Ancient Magnetic Field: A Billion-Year Mystery solved?
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A groundbreaking analysis of lunar samples returned by China’s Chang’e-5 and Chang’e-6 missions is rewriting our understanding of the Moon’s magnetic history. The research, published in Science Advances and Nature, reveals a surprisingly persistent, albeit weak, magnetic field that lasted for nearly two billion years – a finding with notable implications for our understanding of lunar evolution and the potential for past lunar habitability.
Scientists from the Institute of Geology and Geophysics of the Chinese Academy of Sciences analyzed basalt samples from the Oceanus procellarum region, collected by Chang’e-5. These rocks, dating back 1 to 3 billion years, revealed a weak magnetic field, “equal to about 2 to 4 microtesla or less than 10 percent of Earth’s current field strength,” according to the Science Advances study. This finding, featured as a cover story, significantly extends the known lifespan of the lunar dynamo.
“The discoveries help fill a major gap in our understanding of the Moon’s magnetic evolution and suggest that the lunar dynamo continued at least into its middle years,” said Cai Shuhui, corresponding author of the Science Advances paper.
The research suggests continuous deep convection within the Moon,perhaps fueling volcanic activity even after the magnetic field weakened. The energy driving this field may have originated from processes like core crystallization, oscillation, and the accumulation of dense primordial material. This weak magnetic field, while significantly less powerful than Earth’s, still provided a protective shield, impacting space weathering and the preservation of volatile materials like water on the lunar surface.
Further bolstering these findings, a separate study in Nature, based on Chang’e-6 samples from the lunar far side, indicated an unexpected resurgence in magnetic field strength around 2.8 billion years ago. This suggests the lunar magnetic field wasn’t simply a linear decline, but potentially fluctuated throughout its lifespan.
“These two studies suggest that the moon’s magnetic field not only persisted until mid-life, but may also have fluctuated during that period,” cai added.
The Chang’e-6 mission, which returned 1,935.3 grams of lunar samples from the unexplored far side in June 2024, and the Chang’e-5 mission (1,731 grams in December 2020) have been instrumental in these discoveries. These missions, along with the Institute’s previous reports of volcanic activity on the lunar far side dating back 2.8 and 4.2 billion years ago,paint a more complex and dynamic picture of the Moon’s geological history than previously imagined. The implications of this research extend beyond lunar science, offering valuable insights into planetary evolution and the potential for finding evidence of past life beyond Earth.
Moon’s Magnetic Field Reveals Unexpected Persistence
New research analyzing lunar samples brought back by China’s Chang’e-5 and Chang’e-6 missions has provided groundbreaking insights into the Moon’s ancient magnetic field. These findings challenge previous assumptions about its lifespan and suggest it remained active for nearly two billion years, raising new questions about the moon’s evolution and potential habitability.
The Surprising Longevity of the Lunar Dynamo
David, welcome to World Today News.Your team’s latest research is making quite a splash in the scientific community. Could you tell us, in layman’s terms, what you’ve discovered about the Moon’s magnetic field?
Dr. David Chen: thank you for having me. We’ve found that the Moon’s magnetic field, which we call the lunar dynamo, lasted surprisingly long. We previously thought it died out relatively quickly after the Moon formed, but analysis of lunar rocks brought back by the Chang’e missions show its presence even up to two billion years ago. That’s nearly half the Moon’s age!
Unveiling the Power of the Ancient Lunar Dynamo
That’s astonishing! Could you explain what this means in terms of the Moon’s surroundings?
Dr. Chen: A magnetic field acts like a shield, protecting a planet or moon from harmful solar radiation. This finding suggests
that the lunar surface enjoyed this protection for a much longer period.It could have even allowed for the preservation
of volatile materials like water, which could be crucial for understanding the possibility of past lunar life.
Fluctuating Field: Not a Steady Decline
Apparently, your research indicates that the moon’s magnetic field didn’t simply fade away.
Could you elaborate on that?
dr.Chen: That’s right. even more engaging is the fact that our analysis suggests the lunar dynamo wasn’t constant in strength.
It appears to have fluctuated over time. We actually observed a resurgence in its strength around 2.8 billion years ago, based on
samples from the far side of the Moon. This complexity adds a whole new dimension to our understanding of lunar evolution,suggesting
it wasn’t as straightforward as we once thought.
The Chang’e missions: Pillars of Finding
It sounds like these samples brought back by the Chang’e missions have been invaluable. Could you speak to
their significance?
Dr.Chen: Absolutely. These missions are truly game-changers. Without them, this discovery simply wouldn’t have been possible. The
Chang’e-5 and Chang’e-6 missions collected incredibly diverse samples from both the near side and far side of the Moon, providing
us with a unique window into its geological history.
