New dwarf-planet candidate '2026 ED138' found beyond Pluto – spotted in data from Chile's Vera C. Rubin Observatory

1 November 2026 · English Science & Technology

Topics: Science, Sports, Defence & International · 1 November 2026 Current Affairs (UPSC / TNPSC / SSC / RRB)

News

An icy object beyond Pluto, '2026 ED138', was announced on 27 Oct 2026 as a new dwarf-planet candidate (NOIRLab/Rubin statement; also presented at a scientific meeting in Spokane, USA). Matthew Holman of the Center for Astrophysics | Harvard & Smithsonian (CfA) spotted it on 13 Oct using search software he built with Kevin Napier; Mario Jurić (University of Washington) confirmed further detections. The Vera C. Rubin Observatory on Cerro Pachón, Chile, recorded it 30 times on 20 nights between 4 March and 11 July 2026. Its diameter is estimated at about 600–1,500 km; it is now about 46 astronomical units (AU) from the Sun. If confirmed, it would be the sixth IAU-recognised dwarf planet.

Key facts

Background

• IAU definition (2006, Prague General Assembly): a planet must (1) orbit the Sun, (2) be nearly round under its own gravity, and (3) have cleared the neighbourhood around its orbit. A body that fails the third test and is not a satellite is a 'dwarf planet'. Pluto was thus reclassified as a dwarf planet in 2006.
• The five IAU-recognised dwarf planets: Ceres (in the asteroid belt between Mars and Jupiter), Pluto, Eris, Haumea and Makemake (beyond Neptune). Pluto was discovered in 1930 by Clyde Tombaugh; its largest moon is Charon. NASA's New Horizons made the first flyby of Pluto in July 2015.
• Kuiper Belt: a ring of icy bodies beyond Neptune's orbit, about 30–50 AU from the Sun; source of short-period comets. Beyond lie the scattered disc and, far away, the Oort Cloud (source of long-period comets). 1 AU = mean Earth–Sun distance (~150 million km).
• Sci-tech: the Rubin Observatory is a joint project of the US National Science Foundation (NSF) and Department of Energy (DOE), with the world's largest 3.2-gigapixel digital camera. Its 'Legacy Survey of Space and Time' (LSST) will image the southern sky repeatedly for 10 years. It is named after astronomer Vera Rubin, whose work gave evidence for dark matter.

Tamil Nadu link: there is no direct Tamil Nadu link to this discovery. But Tamil Nadu hosts key Indian observatories of the Indian Institute of Astrophysics (IIA) – the Kodaikanal Solar Observatory (Dindigul district, 1899) and the Vainu Bappu Observatory at Kavalur in the Javadhu Hills (Tirupattur district).

Source: Reuters (GMA News), 28–29 Oct 2026; Space.com, Notebookcheck, 28 Oct 2026; The Brighter Side; IAU (2006 Resolution B5)

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