Extended Data Fig. 1: Inferred paleointensities of the core dynamo throughout lunar history as recorded by returned samples.
Modern, high-fidelity measurements (grey) are shown alongside Apollo-era paleomagnetic data (orange). Circles indicate paleointensity determinations and triangles indicate upper limit values for paleointensities. Modern data indicate a lunar dynamo capable of strong surface magnetic fields of approximately 40–100 μT prior to 3.56 Ga (cyan) and weak surface fields of less than 5 μT after ~3.2 Ga (magenta), with a transition period in between (indicated by dashed vertical lines). For reference, the average present-day magnetic field intensity for Earth is 30 μT.
