Rubin Observatory, built around a Menlo Park camera, finds its first possible dwarf planet

A new telescope in Chile whose giant camera was built at SLAC National Accelerator Laboratory in Menlo Park has found its first possible dwarf planet, the Rubin Observatory said Oct. 27.  The object, named 2026 ED138, orbits the sun beyond Pluto.

Astronomers estimate it is 600 to 1,500 kilometers wide, big enough that gravity should have pulled it round, which is what makes something a dwarf planet.  If confirmed, it would join Pluto, Ceres, Eris, Haumea and Makemake, the five dwarf planets the International Astronomical Union recognizes.

How far away, and where

ED138 is about 46 times farther from the sun than Earth is, or roughly 4.3 billion miles.  Light from the sun takes about six and a half hours to get there, by Daily News calculation from the release's figure.  Earth is about the same distance from it.

It is part of our solar system.  ED138 orbits in the Kuiper Belt, the ring of icy bodies beyond Neptune that, according to NASA material, stretches from about 30 to 50 times Earth's distance from the sun.  Its orbit is tilted almost 25 degrees, which makes it a "hot classical" object probably nudged by Neptune, the release says.  The Oort Cloud, the solar system's distant outer shell of comets, lies far beyond it.

It hid for years in a part of the sky crowded with Milky Way stars.  Harvard-Smithsonian astronomer Matthew Holman spotted it in Rubin data, and older images traced its orbit back to 2016.

My first reaction was one of excited disbelief.

What the sun would look like there

From ED138, the sun would deliver about 1/2,100 of the sunlight Earth gets.  That is still bright:  by Daily News calculation from NASA fact-sheet figures, the sun there would look roughly 190 times brighter than a full moon does from Earth, and far brighter than Venus.  But it would be too small to see as a disk, more a blinding star than a ball.

About Rubin

The NSF–DOE Vera C. Rubin Observatory sits 2,647 meters (about 8,700 feet) up on Cerro Pachón in Chile.  Its camera, the largest digital camera ever built for astronomy at 3,200 megapixels, was made at SLAC.  NSF NOIRLab and SLAC run the observatory.

Construction began in April 2015.  The camera was installed in March 2025, the first images came out June 23, 2025, and the observatory switched from construction to operations that October.  Its 10-year Legacy Survey of Space and Time, photographing the whole southern sky again and again, began in June 2026.

National Science Foundation budget documents put NSF's share of construction at $571 million, the Energy Department's camera at $168 million and private funding at about $39 million, roughly $780 million in all.

Infrared observations are still needed to pin down ED138's size.

Source:  NSF–DOE Vera C. Rubin Observatory / NSF NOIRLab release noirlab2626, Oct. 27, 2026; SLAC National Accelerator Laboratory; Rubin Observatory history and site pages; NSF FY2025 budget request, Rubin Observatory chapter; NASA Science, Kuiper Belt facts, and NASA Sun and Moon fact sheets (NASA material, summarized by AI for the Daily News; NASA did not review this story).