Vera Rubin Observatory Spots Potential New Dwarf Planet Beyond Pluto

Less than five months into its decade-long sky survey, the Vera C. Rubin Observatory in Chile has identified a candidate dwarf planet designated 2026 ED138, estimated to be between 600 and 1,500 kilometres in diameter. The object orbits billions of kilometres beyond Pluto, completing one full circuit every 280 years. Amateur astronomer Sam Deen, who helped confirm the discovery, called it "the biggest thing we've found in the entire solar system in 19 years." Remarkably, the object had hidden in plain sight for decades: once researchers identified it in recent Rubin observations, they traced its position back to archival Palomar Observatory photographs from 1954. Its slow movement and position against the dense Milky Way starfield had masked it from previous surveys. On Halloween, Deen planned to watch for an occultation — the object passing in front of a distant star — which could reveal precise details about its size, shape, and whether it hosts moons or rings. Simultaneously, the Observatory identified new Neptune Trojans, ancient icy bodies sharing Neptune's orbit considered among the original building blocks of the solar system, helping to address a long-standing imbalance between known leading and trailing Trojan populations.