Overview
- The Nature study led by Arthur Briaud (CNRS) identifies a solid inner core about 258 kilometers in radius with a density near iron, enclosed by a fluid outer core extending to roughly 362 kilometers.
- Researchers combined lunar laser ranging, gravity mapping and Apollo-era seismic records with modeling to test competing interior scenarios.
- The layered core resembles Earth’s structure, resolving long-standing uncertainty over whether the Moon’s center is solid or fully molten.
- The result supports a global mantle overturn process and informs the timeline of the Moon’s ancient dynamo, active more than 3.5 billion years ago and weakening by about 3.2 billion years ago.
- The findings corroborate a 2011 reanalysis by NASA scientist Renee Weber, with future missions featuring modern seismometers and new laser reflectors expected to provide direct seismic validation.