Oxford University Researchers Debunk Long-Held Mystery of the Moon’s Temporary Magnetic Strength

University of Oxford scientists discover that the Moon’s strong magnetic field was a 5,000-year "titanium blip" caused by rare volcanic events.

By: AXL Media

Published: Feb 26, 2026, 5:55 AM EST

Source: The information in this article was sourced from The Register

Cracking a Decades-Old Lunar Puzzle

For over half a century, scientists have been puzzled by the magnetic signatures found in rocks returned by the Apollo missions. These samples suggested the Moon once possessed a magnetic field as strong as Earth’s, despite having a core much too small to sustain such a force for long periods. On February 26, 2026, a team from the University of Oxford’s Department of Earth Sciences announced they had finally reconciled this contradiction. Their study reveals that the strong magnetic field was not a permanent feature but a series of short-lived, rare volcanic events.

The Role of Titanium in Magnetism

Led by Associate Professor Claire Nichols, the research team identified a direct correlation between the titanium content of "Mare basalts" and their magnetic strength. The study found that only rocks with more than 6% titanium displayed evidence of a strong magnetic field. The researchers theorize that when titanium-rich material sank and melted deep inside the Moon at the core-mantle boundary, it triggered a powerful but fleeting dynamo effect. This process generated an intense magnetic field that likely lasted for only a few thousand years a mere blink in geological time.

Identifying Sampling Bias in Apollo Missions

The study argues that the scientific community was previously misled by "sampling bias." Because the Apollo landing sites were chosen for being relatively flat and accessible, astronauts primarily collected rocks from the Mare basalts, which are naturally high in titanium. Scientists previously interpreted these samples as representative of 500 million years of lunar history. However, it now appears these rocks captured "extremely rare events" that lasted only about 5,000 years, giving a false impression of the longevity of the Moon’s magnetic strength.