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Updated: Jun 26, 2026

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface
Published on: July 30, 2020
Early lunar magnetism
Ian Garrick-Bethell1, Benjamin P Weiss, David L Shuster
1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 54-521, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. iang@mit.edu
Abstract:
It is uncertain whether the Moon ever formed a metallic core or generated a core dynamo. The lunar crust and returned samples are magnetized, but the source of this magnetization could be meteoroid impacts rather than a dynamo. Here, we report magnetic measurements and 40Ar/39Ar thermochronological calculations for the oldest known unshocked lunar rock, troctolite 76535. These data imply that there was a long-lived field on the Moon of at least 1 microtesla approximately 4.2 billion years ago. The early age, substantial intensity, and long lifetime of this field support the hypothesis of an ancient lunar core dynamo.
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