Astronomers utilizing the Vera C. Rubin Observatory in Chile have discovered a distant, ice-covered world beyond Pluto, designated 2026 ED138, which ranks among the largest trans-Neptunian objects ever recorded. Nedd.cz reported that the candidate dwarf planet orbits the Sun roughly 46 times farther than Earth does, remaining hidden for years within the crowded starfields of the Milky Way before detection in October 2026.
Discovery at the Rubin Observatory
The object came to light on the evening of October 13, 2026, when astronomer Matthew Holman of the Harvard-Smithsonian Center for Astrophysics sat at his computer reviewing data from the world’s largest digital camera, Nedd.cz reported. His software searched billions of light sources for subtle shifts between exposures. Holman stated that his initial reaction was a mix of excitement and disbelief because such objects appear very rarely, prompting him to immediately check for coding or processing errors. Centrum.cz noted that the detection process relied on an algorithm specifically designed to find moving targets across repeated observations.
The Vera C. Rubin Observatory in Chile reported on the 28th its first candidate dwarf planet, an object found beyond Neptune and beyond Pluto's orbit.The observatory's camera scans the whole visible sky every few nights, so its first discovery is a test of the survey rather…
Following the initial identification, team members tracked 30 separate detections across 20 nights between March and July 2026, according to Centrum.cz. Archivists also located the body on older images captured in 2016 by the Dark Energy Camera (DECam) in Chile, giving astronomers over a decade of movement data to calculate its orbital path immediately. This tracking of older observations, known as precovery, allowed researchers to substantially refine the calculated trajectory of the body. The Rubin Observatory officially introduced 2026 ED138 as its first dwarf planet candidate on October 27, 2026, at a planetary science conference in Spokane, Washington.
Characteristics and Orbit of 2026 ED138
Current estimates place the diameter of 2026 ED138 between 600 and 1,500 kilometers, depending on its surface reflectivity. A dark surface would imply a larger physical size, whereas a bright, icy coating would indicate a smaller body. For comparison, Pluto measures roughly 2,370 kilometers in diameter. At its current distance of roughly 46 astronomical units from the Sun, the object takes approximately 281 years to complete one full orbit, travelling along a path that tilts nearly 25 degrees relative to the plane of the planets.
Astronomers classify 2026 ED138 as a hot classical Kuiper Belt object, suggesting its path was disturbed long ago by the gravitational influence of Neptune as the giant planet migrated outward during the early history of the Solar System. Mario Jurić of the University of Washington explained that the Rubin Observatory provides unprecedented capability to explore the sky due to its speed, depth, and precision. Holman added that the telescope’s ten-year survey of the southern sky places similar hidden objects within reach.
Frequently Asked Questions
Why did previous sky surveys fail to find 2026 ED138?
The object orbits within a crowded region of the sky close to the plane of the Milky Way, where millions of background stars obscure slow-moving bodies. Older surveys frequently skipped these dense areas or lost the faint signal amid the ambient light.
What makes 2026 ED138 only a candidate dwarf planet?
An object must orbit the Sun, remain free of being a satellite of another body, possess enough mass for its own gravity to pull it into a roughly spherical shape, and fail to clear its orbital neighborhood in the manner characteristic of true planets. While its estimated size suggests sufficient mass, astronomers require further infrared observations to measure its thermal radiation and confirm its true dimensions.
How far is the new object from Earth and the Sun?
The candidate dwarf planet sits approximately 46 astronomical units from the Sun, meaning it is 46 times farther away than Earth. Its elongated orbit brings it as close as 37 astronomical units and pushes it out to roughly 49 units.
Future Discoveries in the Outer Solar System
Researchers emphasize that studying such distant objects yields insights into the past evolution of the entire planetary system. However, exactly how many similar objects remain awaiting formal classification is still not reliably known by anyone.