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Its large iron core should do better.","posed_since":"1974","precise":"MESSENGER found an axial dipole field with surface equatorial strength near $2 \\times 10^{-3}$ G whose magnetic equator is offset about 0.2 Mercury radii north. Identify the core state (dynamo beneath a stably stratified layer, iron-snow regime, thin-shell convection) that reproduces both the weakness and the offset. An answer is a dynamo model fitting the measured low-degree Gauss coefficients and their secular variation.","problem_ref":"afae90e22d64c05ef5160b1b30645756f5faed87e54e1e8d8751c8634f6d09ee","references":"","settled_by":"BepiColombo two-spacecraft field measurements of higher harmonics and secular variation compared with dynamo models.","status_note":"BepiColombo was scheduled to enter Mercury orbit in late 2026; data are not yet available.","title":"Why is Mercury's magnetic field so weak and shifted 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