{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"aade67da2f9d64f0bd4cca5d668aed5edfe0a97f9910126f09c948ade0bd89ed","created":"2026-10-03T07:18:02Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","ed264645728bed1ec687ad4bd3875390250b8f5cab07bf83f47c6553d9b6de0f"],"salt":"2c2e144f636cba92f4c57a1fab0791aef6584ed7d0ba2b0486b80227a3f12226","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"cosmo.hubble-tension.ladder-free-h0","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"ed264645728bed1ec687ad4bd3875390250b8f5cab07bf83f47c6553d9b6de0f","relation":"special_case"}],"plain":"Some methods measure the expansion rate in one step, using gravitational waves from colliding neutron stars or time delays between multiple images of a lensed quasar. They avoid both the distance ladder and the early-universe ruler.","posed_since":"","precise":"Measure $h$ to 1 percent from at least one method independent of both the distance ladder and $r_d$: gravitational-wave standard sirens, strong-lens time delays with independent mass-profile constraints, water-maser distances, or $r_d$-free galaxy clustering. An answer is $h$ with uncertainty below 0.007 and a statement of which side it matches.","problem_ref":null,"references":"","settled_by":"About 200 standard sirens with electromagnetic counterparts, or tens of time-delay lenses with spatially resolved stellar kinematics.","status_note":"A single quadruply lensed quasar (TDCOSMO XXV, 2026) gives $h = 0.732 (+0.048, -0.047)$; no ladder-free method reaches 1 percent.","title":"Does the tension persist in measurements independent of ladders and rulers?","topic_ref":"7274d4f6495a643569c4fecb6957a3a928df8172b93a2b26d1dc5043075bd891"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"393900eb8aa374ed103d98c58c7a4c4450329e94cc12f9903c48443745288e54","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"ec364457d130def5afbc216018004b2a3c675fa889872cf3b883a23bdb6c7e03","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Bq3Kw2kVu74zFi9ryjjHdQKmk8rl00NwKQdP8O30WWHeuPC90Nkj3htEEts5cCwHpDHEhpfgtpLj7_XuYkZhCw"},"schema":"pubphys.envelope/1"},"record_hash":"393900eb8aa374ed103d98c58c7a4c4450329e94cc12f9903c48443745288e54","leaf_index":1258}