In the distant cold expanses beyond Pluto's orbit, astronomers have spotted an object that may well become one of the largest known dwarf planets. On 27 October 2026, the International Astronomical Union, through the Minor Planet Center, officially announced the candidate 2026 ED138. It was discovered by the Vera Rubin Observatory, which operates in partnership with the support of the U.S. National Science Foundation and the Department of Energy.
On the evening of 13 October, Matthew Holman of the Harvard–Smithsonian Center for Astrophysics was running through his search algorithm data collected by the telescope earlier in 2026. The code, created together with his colleague Kevin Napier, compares billions of individual flashes of light and looks for those that belong to the same moving body. Among them, a bright and distant object suddenly emerged. Holman's first reaction was joyful disbelief. Such large bodies on the outskirts of the Solar System are extremely rare, so he immediately began checking whether the algorithm or he himself had made a mistake.
The doubts were quickly dispelled. Mario Jurić of the University of Washington, the observatory's lead specialist on the Solar System, found twenty more observations in catalogues and images, the earliest of which date back to 4 March 2026. In total, the Simonyi telescope recorded ED138 thirty times over twenty nights — from March to July. Then archival frames from the Dark Energy Camera on the four-metre Blanco telescope were brought into the work. Thanks to the ADAM Precovery service, it was possible to "extend" the object's orbit back all the way to 2016. More than ten years of its path were mapped out.
ED138 is currently located at approximately 46 astronomical units from the Sun — farther than Pluto's average distance. It is a typical trans-Neptunian object. Its orbit is inclined almost 25 degrees to the plane of the Solar System, which classifies it as a "hot" classical Kuiper Belt object. At some point, Neptune's gravity probably pushed it off a calmer trajectory.
Based on brightness, distance and the presumed reflectivity of its surface, the candidate's size is estimated at 600–1500 kilometres. Icy bodies of such size usually take on a rounded shape under their own gravity — one of the main conditions for being considered a dwarf planet. If the estimate is confirmed, ED138 will join the ranks of Pluto, Eris, Haumea, Makemake and Ceres. The exact dimensions have yet to be refined with the help of infrared observations.
The object long hid in a dense star field near the plane of the Milky Way. Ordinary telescopes lost it among millions of background sources. The Rubin Observatory was able to pick it out thanks to its regular and deep survey of the entire southern sky and powerful algorithms that separate slowly moving points from stationary stars. This is not its first major find. Even before the official start of the Legacy Survey of Space and Time, the team submitted data to the Minor Planet Center on more than eleven thousand new asteroids, among which are about 380 trans-Neptunian objects. At the time, people said this was merely the tip of the iceberg. Now those words are being confirmed.
The discovery shows how much is still hidden on the outskirts of our planetary system. Over ten years of continuous imaging, the Rubin Observatory will scan the sky again and again, and other large bodies missed by previous surveys will almost certainly come to light. Each such object is another fragment of ancient history: evidence of the migration of the giant planets, the scattering of material and the complex gravitational choreography that once shaped the world in which we live.
In the cold darkness beyond Pluto, an icy world is slowly moving that remained invisible for decades. And only now, thanks to a huge mirror, the largest digital camera and smart programs, has it finally come into our field of view. The Universe continues to surprise — not with loud flashes, but with the quiet appearance of new worlds in the farthest orbits.
