{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"e226a8301112f9b88cb8876d25c363d678510d62f83cfa2f10f5d1fbb72c505d","created":"2026-10-03T07:18:02Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"4b3511fb185d51eaeeb67a92c7ba6cfc5a4d39a8082b0e48477a82fb52d0406d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"cosmo.hubble-tension.origin","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"Two careful ways of measuring how fast the universe expands today give different answers. The cause could be a measurement error or new physics.","posed_since":"","precise":"Write $H0 = h x 3.24e-18\\ \\mathrm{s}^{-1}$. The SH0ES Cepheid plus type Ia supernova ladder gives $h = 0.730 \\pm 0.010$, while Planck CMB in LCDM gives $h = 0.674 \\pm 0.005$. Identify whether the discrepancy comes from distance-ladder systematics, from physics before recombination that shrinks the sound horizon, or from late-time physics, with a model that fits all data at least as well as LCDM.","problem_ref":null,"references":"","settled_by":"Independent one-percent $H0$ measurements that agree with one side, plus a model or systematic that removes the discrepancy without spoiling other fits.","status_note":"2025 to 2026 JWST cross-checks by SH0ES find Cepheid, TRGB and JAGB distances agree within about 0.03 mag, while CCHP finds $h$ near 0.70.","title":"What causes the Hubble tension?","topic_ref":"7274d4f6495a643569c4fecb6957a3a928df8172b93a2b26d1dc5043075bd891"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"ed264645728bed1ec687ad4bd3875390250b8f5cab07bf83f47c6553d9b6de0f","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"474cd435ddf978b9c88f206b55416d9d53d7116d4f3a498de1a5bc81f994d3e6","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"PjCeN7iiFGGNi0iuutSPqn9uONK1xWjAwWGFLwGYpNKx9l9FzkoryHL-rLeU9KVTi7LxEmFjqx9fXErSyYIOBg"},"schema":"pubphys.envelope/1"},"record_hash":"ed264645728bed1ec687ad4bd3875390250b8f5cab07bf83f47c6553d9b6de0f","leaf_index":1255}