Astronomers have detected a massive, icy body orbiting in the distant reaches of the solar system, unveiling what may be the first dwarf planet discovered in roughly two decades, researchers announced this week.
The candidate world, provisionally designated 2026 ED138, circles the sun in the Kuiper Belt beyond Neptune. Scientists estimate its diameter ranges between 370 and 930 miles across, according to reports from CNN and Phys.org. If those dimensions hold true, the object possesses sufficient gravitational mass to pull itself into a spherical shape, satisfying a central requirement for dwarf planet classification.
To date, the International Astronomical Union recognizes only five dwarf planets: Pluto, Ceres, Eris, Haumea and Makemake. Confirming 2026 ED138 would expand that exclusive roster for the first time in years.
A hidden world in the Milky Way
Matthew Holman, a senior astrophysicist at the Center for Astrophysics | Harvard & Smithsonian, detected the object on Oct. 13 while testing search algorithms codeveloped with colleague Kevin Napier. The software sifted through vast catalogs gathered by the NSF-DOE Vera C. Rubin Observatory, located atop Cerro Pachón in northern Chile.
Holman said his initial reaction was one of disbelief, prompting immediate checks to ensure the result was not a computational glitch. Subsequent searches led by University of Washington astronomer Mario Jurić, who serves as Rubin’s solar system lead scientist, confirmed 30 distinct sightings across 20 nights of telescope operations between March and July.
The object escaped detection for decades partly because its path crosses the dense star fields of the Milky Way, where crowded starry backgrounds obscure moving points of light. The body also travels in an orbit tilted roughly 25 degrees relative to the main orbital plane of the solar system, likely knocked off course by ancient gravitational encounters with Neptune, Space.com reported.
“Rubin will image the whole southern sky again and again for 10 years, so any others hiding in the places earlier surveys skipped are now within reach,” Holman said in a statement.
Tracking a decade of archival data
After isolating the object’s path, researchers traced it back through archival survey images taken by the Dark Energy Camera on the Víctor M. Blanco 4-meter Telescope in Chile. Those records revealed sightings dating to 2016, providing more than a decade of baseline trajectory measurements.
Data recorded by the Minor Planet Center show that 2026 ED138 takes approximately 281 years to complete a single trip around the sun. It swings as close as 36.9 astronomical units and ventures as far as 49 astronomical units. Currently, the object is roughly 46 astronomical units from the sun, placing it deeper in space than Pluto’s average distance of 40 astronomical units, where one unit equals the roughly 93 million miles between Earth and the sun.
Although invisible to the naked eye, the object reflects enough sunlight that skilled amateur astronomers using capable equipment may spot it, Holman told CNN.
Next steps for confirmation
Astronomers caution that 2026 ED138 remains an unconfirmed candidate until observatories can nail down its exact physical size. Because a smaller body with an icy, highly reflective surface can shine as brightly as a darker, larger body, optical brightness alone cannot prove spherical mass.
Researchers expect to target the distant world using infrared instruments, such as NASA’s James Webb Space Telescope, to measure its thermal emission and surface characteristics. If confirmed, the International Astronomical Union will assign the body an official catalog number and a formal name.
