{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"00de6aaf928e21ec3c66886a04abb70ee53b0413b9f441a1fce9844da496d2ca","created":"2026-10-03T07:18:03Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"6db1f6d36e575dd87044b444fe4517ff848f9dbb917b2771dc5e75f2f121dc2d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"earth.inner-core.inner-core-age","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"Estimates of the inner core's age range from about half a billion to several billion years. The answer depends on how fast the core loses heat.","posed_since":"","precise":"Determine the inner-core nucleation age $t_{ic}$. Thermal models give $t_{ic}$ of roughly 0.5 to 1.5 Gyr for high core conductivity and much older values for low conductivity; paleomagnetic candidates include the Ediacaran ultra-weak field near 565 Ma and a Mesoproterozoic intensity rise near 1.3 to 1.5 Ga. An answer is $t_{ic}$ with uncertainty below about 0.2 Gyr consistent with core energetics and the paleointensity record.","problem_ref":null,"references":"","settled_by":"A resolved core conductivity and heat budget combined with a dense, reliable Precambrian paleointensity record showing a unique nucleation signature.","status_note":"","title":"When did Earth's solid inner core begin to grow?","topic_ref":"7cfe9fc58e1f6e93abcae219320fa93156a5400d6286e67a83bb0bb8981c5f56"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"af1bafbfa6747b6262a2e607fd3b79dc32a9c30a8cab8f52e978c43ec6647472","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"9e7797db9f696a471e44d79537399de373e132b2e4cce15f62fa41d4583d2525","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"jSZjvqhyNiTzJp2ss2omdlWh3U0phvZOnERu9tmkCtL0I0BGCw41GmQOws1Xhzjp7T3xWSR3M25XP7SiMZLBAw"},"schema":"pubphys.envelope/1"},"record_hash":"af1bafbfa6747b6262a2e607fd3b79dc32a9c30a8cab8f52e978c43ec6647472","leaf_index":1331}