New analyses of data from the MESSENGER probe suggest that Mercury's current magnetic field is sufficient to explain most of the magnetism observed in its crust. This finding challenges the prevailing hypothesis that an active planetary dynamo was required in Mercury's distant past to magnetize its crust, an idea that has been fundamental to understanding the geological and magnetic evolution of the innermost planet in the solar system.

Traditionally, it has been assumed that magnetic anomalies in Mercury's crust were remnants of a much stronger global magnetic field in its early stages, generated by a dynamo in its core. However, the new studies, based on a comprehensive re-evaluation of data collected by NASA's MESSENGER mission, propose that the current dipolar magnetic field, although weak, has interacted with the crust over eons, inducing the observed magnetism. This simplifies the model of Mercury's magnetic history, eliminating the need to postulate an ancient, powerful dynamo that would have subsequently weakened drastically.