Updated

Astronomers at the Vera C. Rubin Observatory have reported 2026 ED138, a possibly large icy world beyond Pluto that could become the sixth officially recognized dwarf planet. Matthew Holman of the Harvard & Smithsonian Center for Astrophysics spotted the object on October 13 in Rubin observations, using software he developed with Kevin Napier. Mario Jurić of the University of Washington found 20 more detections, some from March 2026, and images from 2016 in other surveys, allowing the team to trace more than a decade of its orbit. ED138 lies about 46 astronomical units from the Sun, beyond Pluto's average of about 40 au, in a crowded part of the sky near the plane of the Milky Way that hid its faint motion. ScienceDaily estimates it is 600 to 1,500 kilometers across, and Jurić put it at roughly 1,000 kilometers, the largest trans-Neptunian object found in about 20 years. If confirmed, it would join Pluto, Ceres, Eris, Haumea and Makemake as a dwarf planet, though more observations are needed to establish its size and whether its gravity has made it round. ScienceDaily reported that more unknown worlds may lie far beyond Neptune, and Rubin's ten-year survey of the southern sky, which officially began in June 2026, is expected to find more.