A Possible New Dwarf Planet Is Hiding Beyond Pluto — and It Was in Old Photos All Along
There may be a new world in our Solar System, and it was hiding in plain sight. Astronomers using the Vera C. Rubin Observatory in Chile have found a large icy body, provisionally called 2026 ED138, orbiting the Sun beyond Pluto. At an estimated 600 to 1,500 kilometres across, it could become the sixth officially recognised dwarf planet — and it had been photographed years ago, but nobody had recognised it as a single moving object.
The discovery was announced on 27 October 2026 by the International Astronomical Union's Minor Planet Center, and presented the same day by the Rubin Observatory team at a planetary science meeting in Spokane.
Found by a search code, not a telescope eyepiece
The discovery was made on the evening of 13 October 2026 by Matthew Holman, a senior astrophysicist at the Center for Astrophysics | Harvard & Smithsonian. He was running data collected by Rubin earlier in 2026 through a search program he had written with colleague Kevin Napier. The telescope had photographed the object 30 times on 20 nights between 4 March and 11 July 2026 — but the object is so distant and slow-moving that it took a computer search to pick it out. Digging further, the team found the same object in older telescope images dating back to February 2016.
2026 ED138 is currently about 46 astronomical units from the Sun — one astronomical unit is the average distance from Earth to the Sun — so it sits well beyond Pluto's orbit. Its size is an estimate, worked out from how bright it looks, how far away it is, and how reflective its surface is assumed to be. Icy bodies this large are expected to be pulled round by their own gravity, which is one of the requirements for dwarf planet status.
A candidate, not yet confirmed
It is important to say what has not been proved yet. The object's exact size is unknown, and whether it is truly round has not been observed. Infrared observations are needed to measure its size properly and confirm its nature as a dwarf planet. If it is confirmed, 2026 ED138 would join the five dwarf planets recognised by the International Astronomical Union: Pluto, Ceres, Eris, Haumea and Makemake.
The find is also a sign of what is coming. Rubin Observatory's ten-year Legacy Survey of Space and Time began in June 2026, and it is expected to discover many more distant icy bodies. Some of them may have been sitting in old photographs for years, waiting for someone to look in the right way.
If your child looks up at the night sky and asks what is still out there to find, a first lesson in astronomy or physics can start with Pluto's possible new neighbour and end with how a telescope the size of a small car maps the whole sky. Book your first lesson
Sources:
- NSF–DOE Vera C. Rubin Observatory, "Rubin Observatory Reveals Its First Dwarf Planet Candidate in Our Solar System", 27 October 2026, as reported by phys.org: https://phys.org/news/2026-10-rubin-observatory-reveals-dwarf-planet.pdf
- Holman, M. et al., "2026 ED138: A Large Trans-Neptunian Object in Early Rubin Observatory Data", arXiv:2610.38693 (2026)
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