Astronomers have uncovered a mysterious and massive object lurking in the outer reaches of the solar system that could be confirmed as a new dwarf planet. Temporarily designated as 2026 ED138, the distant world was discovered in data collected by the Vera C. Rubin Observatory during preparations for its upcoming 10-year survey of the southern sky.
The discovery was announced in late October 2026 at a meeting of the American Astronomical Society’s division for planetary sciences in Spokane, Washington. Matthew Holman, a researcher with the Center for Astrophysics | Harvard & Smithsonian and a member of the Rubin Operations team, first identified the object while analyzing data on October 13, 2026.
“My first reaction was one of excited disbelief,” Holman said in a statement. “Objects like this are very rare, so I immediately started checking whether I or the code had done something wrong.” Subsequent checks through the telescope’s catalog confirmed the reality of the detection.
Characteristics of Dwarf Planet Candidate 2026 ED138
Located as a trans-Neptunian object, 2026 ED138 orbits the sun far beyond both Neptune and Pluto. It currently resides about 46 astronomical units (AU) from the sun, placing it outside Pluto’s average distance of roughly 40 AU. (One AU is the distance from the Earth to the sun, or about 93 million miles.)
Initial estimates place the object’s diameter between 600 and 1,500 kilometers (373 to 932 miles). Researchers note it may be one of the largest and brightest objects yet spotted in its specific region, potentially rivaling established dwarf planets like Makemake and Haumea in size.
Data also show that the orbit of 2026 ED138 is tilted by roughly 25 degrees relative to the main plane of the solar system. Scientists believe this orbital tilt indicates that the object experienced a gravitational interaction with Neptune in its past, which knocked it off its original path.
What Lies Ahead for the Discovery
While the discovery has generated immense excitement within the astronomical community, 2026 ED138 remains a candidate until further observations can be completed. Upcoming data collection using other telescopes will be necessary to verify its exact size, mass, and round shape.
If future observations validate these properties, 2026 ED138 will join an elite club of officially recognized dwarf planets in our solar system. Currently, the International Astronomical Union formally recognizes just five dwarf planets: Pluto, Ceres, Eris, Haumea, and Makemake. Astronomers hope that the Vera C. Rubin Observatory, with its powerful capabilities, will uncover many more hidden worlds in the distant cosmic neighborhood.
