A team of astronomers announced on Oct. 27 that a distant body, labeled 2026 ED138, has been detected well beyond Pluto’s orbit. The find comes from data gathered by the Vera C. Rubin Observatory, a brand‑new facility perched on a Chilean summit. Funded jointly by the U.S. National Science Foundation and the Department of Energy’s Office of Science, the observatory began a decade‑long sky survey in June 2026, deploying the world’s largest digital camera to hunt for objects previously invisible to Earth‑based telescopes. Preliminary measurements place the object’s diameter somewhere between 370 and 930 miles, a range that would make it one of the biggest dwarf‑planet candidates identified in the outer reaches of the solar system.
Discovery process and the role of advanced software
The object was first flagged on Oct. 13 by astronomer Matthew Holman, who was sifting through early‑year observations with custom software he co‑developed with colleague Kevin Napier. While scanning the massive dataset, Holman noticed an unusually bright point moving at a distance that implied a size far larger than typical trans‑Neptunian objects. He described his reaction as “one of excited disbelief” and immediately began double‑checking both his calculations and the code for possible errors. The object resides in a densely populated section of the sky near the Milky Way, where millions of background stars have historically masked faint, slow‑moving bodies. Rubin’s continuous monitoring of the entire Southern Hemisphere, paired with algorithms capable of parsing millions to billions of light points, finally allowed the team to isolate the moving signature of 2026 ED138 amid the stellar crowd.
Scientific significance and future observations
At an estimated distance of about 4.3 billion miles from the Sun, 2026 ED138 orbits farther out than Pluto, which averages roughly 3.7 billion miles from the Sun. Classified as a trans‑Neptunian object, it circles the Sun beyond Neptune, the solar system’s outermost planet. Researchers plan additional imaging and photometric studies to refine the object’s size, shape, and surface characteristics, aiming to determine whether it meets the International Astronomical Union’s criteria for dwarf‑planet status. Holman noted that confirmation would place the body among a very limited collection of known dwarf planets. The Rubin Observatory is slated to repeatedly image the southern sky over the next ten years, a strategy that should reveal more hidden objects in regions overlooked by earlier surveys.
Dwarf planets are defined as bodies that orbit the Sun and are massive enough for their self‑gravity to shape them into a near‑round form, yet they share their orbital zones with other debris and have not cleared the neighborhood of other material. Pluto, discovered in 1930, was reclassified from planet to dwarf planet in 2006 under this definition. The identification of 2026 ED138 adds to a growing list of distant solar‑system objects that are reshaping our understanding of the region beyond Neptune.
Helene Elliott is the Lead Science & Space Reporter at News Raise. She reports on aerospace missions, astrophysics discoveries, quantum research, and environmental technology.
