{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"4ede5e09687e190d03e89595274786bba9210cacffb1051c80cf6947f8c901a4","created":"2026-10-03T07:18:03Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"8f1af876b15189ad056bc45ebd3923393d84ec4935ab82b3a4a124949bc2c6e3","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"earth.solar-system-dynamics.planet-nine","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"Some very distant icy bodies have orbits that seem lined up in a way that a hidden planet several times Earth's mass could explain. Others argue the alignment is an accident of where telescopes looked.","posed_since":"2016","precise":"Determine whether the apsidal and nodal clustering of distant trans-Neptunian objects (semimajor axis above about 250 au, perihelion above about 40 au) is statistically significant after correcting for survey selection, and whether it requires an undetected planet of roughly 5 to 10 Earth masses on an eccentric orbit at a few hundred au. An answer is a detection, or an exclusion of the proposed parameter space by direct search and by unbiased orbital statistics.","problem_ref":null,"references":"","settled_by":"Direct detection by deep wide-field surveys, or a large, well-characterized sample of distant objects from the Rubin Observatory survey showing no significant clustering.","status_note":"No detection as of 2026; the Rubin Observatory, whose first images were released in 2025, is expected to enlarge the distant-object sample substantially.","title":"Is there an undiscovered planet beyond Neptune?","topic_ref":"b929a620dac9f17771effc8b71b936420a6fad08ab629dcf3f51f65829dd7067"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"a9e251ec1577899b002b1aa489d161c31ade72e37b5ed8706b8f72d89576ffa0","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"7f10f17551b2153e5493596f5dffb4939ba1aa0a389ed63e79312ef9bb0041c9","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"j0931jOlCW8XTJCg_dvmHg1Hv4Jgaus5FNEol3HiKU_Yi3NTPiJJi8z9ZV3-oPQA4jm7n3QtrHuIoIQQOaGQDg"},"schema":"pubphys.envelope/1"},"record_hash":"a9e251ec1577899b002b1aa489d161c31ade72e37b5ed8706b8f72d89576ffa0","leaf_index":1367}