Rubin Observatory Spots Possible Dwarf Planet Beyond Pluto—the Biggest in 20 Years
“Finding an object this big, roughly 1,000 kilometers [621 miles] across, is something that happens maybe once in a generation,” Mario Jurić, a professor of astronomy at the University of Washington and leader of Rubin’s solar system team, said in a statement. “It’s the largest trans-Neptunian object found in about 20 years, and Rubin turned it up while we were still commissioning the telescope.” This dwarf planet candidate has been provisionally named 2026 ED138, and Jurić presented the discovery alongside Matthew Holman, a senior astrophysicist at the Harvard & Smithsonian Center for Astrophysics, at a press conference on Tuesday. Holman first spotted ED138 while running Rubin data through a search code he co-developed to compare billions of detections of moving objects and find those that correspond to the same object. This object immediately caught his attention, as its brightness…