{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"acb120a2cdc469c6cd371b04c2351a60eefcbc2fae84cbe9c80f4fd18b9a7254","created":"2026-10-03T07:17:55Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"beb3de0aedf501402f007a74ce23efbd575541989b9aba48da2495cb9ab50c33","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"astro.interstellar-objects.oumuamua-acceleration","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"'Oumuamua sped up slightly as it left the Sun, as comets do when gas jets off them, yet no gas or dust was seen. The push must come from something invisible to the instruments used.","posed_since":"2018","precise":"1I/'Oumuamua showed a radial non-gravitational acceleration of approximately $5x10^{-4}\\ \\mathrm{cm}/\\mathrm{s}^2$ at $1\\ \\mathrm{AU}$ scaling roughly as $r^{-2}$, with no detected coma and tight limits on CO, CO2 and dust. Identify the cause: H2 outgassing from radiolytically processed water ice, N2 or H2 ice composition, or radiation pressure on a very low-density body, consistent with its light curve, size and thermal limits.","problem_ref":null,"references":"","settled_by":"A model that fits the acceleration, the absence of detected gas and dust, and the light curve, tested on future similar objects with spectroscopic sensitivity to H2 and N2 outgassing.","status_note":"","title":"What caused the non-gravitational acceleration of 1I/'Oumuamua?","topic_ref":"91b19694864393f36b4b275d23c992a261a21df30ecbe64b28d991279c458961"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"c6d8496825d990027b7b5625c8fe39f1700448c168dc406ec923aa52ba3b7cec","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"e318d54e86c854d8cac8bb282a68e6d5ab806412c03927368db8782b34790349","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"dIf5aUNHn81Le3pggRBegybSCfAxgVO7UWRkyOPll4ZwWtWXjixOdogAdsdsTjy7BrtXIrkjyODtJXHAHesiCA"},"schema":"pubphys.envelope/1"},"record_hash":"c6d8496825d990027b7b5625c8fe39f1700448c168dc406ec923aa52ba3b7cec","leaf_index":563}