Buried Volcano Under Lunar Dewar Swirl Points to Ancient Moon Dynamo

Researchers from ETH Zurich, DLR and the Institute of Applied Geosciences analyzed GRAIL, Lunar Prospector and Kaguya data to show that a buried volcano about 60 km wide lies beneath the Dewar swirl on the Moon's far side. Its magnetization could only have formed under a long-lived magnetic field around 4.22 billion years ago, confirming the Moon once had a dynamo.

• The buried volcano beneath the Dewar swirl is ~60 km wide and 5–9 km deep
• Its magnetization dates to about 4.22 billion years ago
• Field strength is estimated at ~11 microteslas versus ~50 microteslas on Earth
• Data came from GRAIL, Lunar Prospector and Kaguya spacecraft