{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"b7652b34f10a3017ffbb5fb7443300f3ccbb764ef5b02b1eee4680bd213cc26b","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["afae90e22d64c05ef5160b1b30645756f5faed87e54e1e8d8751c8634f6d09ee","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"3d5447906216a3e65f2e327f679224de6e32930c219af409e3ac3ad7db431424","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"earth.planetary-dynamos.mercury-weak-field","kind":"phenomenon","literature_status":"open","n":"2","parents":[],"plain":"Mercury has an active dynamo (a field generator made by flowing liquid iron) but its field is about a hundred times weaker than simple scaling predicts, and its center is shifted toward the north pole. 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 north?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f3ab1e81369ce872734edc7acf1fa625e7b92b6899e9d4286a6d4bd669e7d701","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"b399509d9e967e9c6e870fac115cb5fb05be03538e125ef5799f8d75e942d675","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"XbJUfskCtV3fN1yp9fa4glHuX-AMqVYhxfyuUqPKhqhICiMWIZt_08hStQHhQYc6m3cXrSi-i-K_UguUfhYoAw"},"schema":"pubphys.envelope/1"},"record_hash":"f3ab1e81369ce872734edc7acf1fa625e7b92b6899e9d4286a6d4bd669e7d701","leaf_index":3232}