{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"15d28a791441b0561289b4be4e02e439dfcf8de3676698d1798b5cc4453b93d1","created":"2026-10-03T07:18:03Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"1f9a8705021922ba21ddb566fdf7fdc4c25becaf41a9e838442db1bb9d4ca5b5","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"earth.solar-system-dynamics.mercury-core","kind":"phenomenon","literature_status":"open","n":"1","parents":[],"plain":"About 70 percent of Mercury's mass is in its metal core, far more than for Earth or Mars. It may have lost its rocky outer layers in a giant impact, or formed from material enriched in iron near the Sun.","posed_since":"","precise":"Explain Mercury's metal mass fraction (about 0.7) by mantle stripping in one or more hit-and-run or giant impacts, by chemical or magnetic sorting of iron-bearing solids in the inner disk, or by evaporation, consistent with MESSENGER's detection of a surface high in volatile elements (high K/Th, S, Na). An answer is a scenario matching bulk composition and volatile inventory.","problem_ref":null,"references":"","settled_by":"BepiColombo measurements of Mercury's interior and surface composition combined with formation models that predict both the metal fraction and the volatile abundances.","status_note":"BepiColombo is scheduled to enter Mercury orbit in late November 2026, with interior and surface-composition measurements to follow.","title":"Why does Mercury have such an outsized iron core?","topic_ref":"b929a620dac9f17771effc8b71b936420a6fad08ab629dcf3f51f65829dd7067"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"d44c053d7f99ab593381a1200995b357b09aeda9b41417e68946b7e8978a3fe6","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"b6b0a2b4ad459bb5ea903cb20e92558c4ab8c2ca968a7ee891be0ece10851bf5","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Stu3q0TS5wZBfwInL1MYuiS_WuayHwi24BnEIBJGcfxqBDjPVq3PfsGhozj3ZtUNqyLd3RulmgJiwiyvql9vBw"},"schema":"pubphys.envelope/1"},"record_hash":"d44c053d7f99ab593381a1200995b357b09aeda9b41417e68946b7e8978a3fe6","leaf_index":1366}