2009/01/15 by I. Garrick‐Bethell, B. P. Weiss, David L. Shuster +1 · 2 citations
Physics and Astronomy · Biochemistry, Genetics and Molecular Biology · #Planetary Science and Exploration #Astro and Planetary Science #Geomagnetism and Paleomagnetism Studies
paper · doi:10.1126/science.1166804
openalex publication_date 2009/01/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
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.