{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"e42c104ac3bef9e9e9c0ac91b4a2ec04286cb370e47ee0ccbc4b3a6c743f8771","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b","fb842848d5f62fff9d1251605824309bcd8cc8db829286506c08e88b4a61758e"],"salt":"56d3fb63b88b881a90114d1c674b8b741aa10b506ae322f67f2b9e56c65d2c54","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"astro.biosignatures.false-positives","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Oxygen and methane can sometimes be made by sunlight splitting water or by volcanic and rock-water chemistry, without life. A sign of life must be distinguishable from these.","posed_since":"","precise":"Enumerate and quantify abiotic pathways that produce detectable $\\mathrm{O_2}$, $\\mathrm{O_3}$ or $\\mathrm{CH_4}$ plus $\\mathrm{CO_2}$ disequilibrium on rocky planets: $\\mathrm{H_2O}$ photolysis with hydrogen escape, $\\mathrm{CO_2}$ photolysis in dry atmospheres, serpentinization and volcanic outgassing. For each, derive spectral discriminants (CO, O4, $\\mathrm{H_2O}$ abundance, redox state) measurable by a Habitable Worlds Observatory-class telescope. The answer is a classified list with abundance ranges and discriminants.","problem_ref":"fb842848d5f62fff9d1251605824309bcd8cc8db829286506c08e88b4a61758e","references":"","settled_by":"Coupled photochemical, geochemical and escape models over the plausible parameter range, with synthetic spectra at expected telescope resolution and signal to noise.","status_note":"","title":"Which non-biological processes can mimic oxygen or methane biosignatures?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"6dfda720f45a415f063b3e157f36a7b7d3c65eea5b5ea04d0a0c7eaf7fb9a280","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"e23e7d3caea8994088a11f7073b1e5c723180e37cecea1eb7fa05926740148de","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"NtDoCKHtdcq7gvEa7GijCWwiCsuiOosLxWkEtQUrJexQc6jtc_dHs4BfFfzyvOfn9w_WIi7V0ExTRkjRqZByAA"},"schema":"pubphys.envelope/1"},"record_hash":"6dfda720f45a415f063b3e157f36a7b7d3c65eea5b5ea04d0a0c7eaf7fb9a280","leaf_index":2300}