This stellar new discovery needed some “space” before revealing itself. 

Scientists have long struggled to map the region of space beyond Pluto, relying on scattered discoveries and indirect clues from other planets’ movements.

Now, researchers have announced a new discovery from the Vera C. Rubin Observatory, high atop Cerro Pachón in Chile.

A large object in the Kuiper Belt — a distant region of icy and rocky bodies past Neptune — appears to be a new candidate dwarf planet. Named 2026 ED138, its entire orbit lies within Pluto’s distance range from the Sun, yet it was only just discovered. 

The Rubin Observatory features the largest digital camera ever built for astronomy, capable of capturing a patch of sky equal to 40 full moons in a single shot. The telescope first saw light in June 2025, and by March 2026, the object entered its field of view. Since then, the team traced it through 30 detections across 20 nights of Rubin observations, dating from 4 March to 11 July 2026.

The light turned out to be one of the largest objects ever discovered past Neptune, potentially rivaling the size of other above-average dwarf planets, such as Makemake and Haumea.

Astrophysicist Matthew Holman of the Harvard-Smithsonian Center spotted the object on Oct. 13, 2026, while analyzing Rubin observations using software developed with colleague Kevin Napier.

Searching older data, the team found the object in images from the Dark Energy Camera dating back to February 2016. The camera had also captured it in 2017, 2018, 2019, and 2023. Holman noted that objects like this are “very rare.” Double-checking his work in “excited disbelief,” he made sure no errors had been made.

The region beyond Neptune begins roughly 30 astronomical units (AU) from the Sun, and everything we know suggests far more remains hidden. The Kuiper Belt extends out to 55 AU, beyond which lies the theoretical Oort Cloud.

Thousands of objects past Neptune hint at materials in even more distant reaches. Spotting them is extraordinarily difficult because they reflect very little sunlight and appear faint to telescopes.

They are also extremely cold, giving off very little heat radiation (infrared light) for sensors to pick up.

If 2026 ED138 is on the larger end of size estimates, it could rank alongside other dwarf planets — meaning its own gravity would be strong enough to pull it into a round shape. The finding shows Rubin’s ability to repeatedly scan swaths of the sky and pick out faint, slow-moving bodies that earlier surveys missed — and reveal objects hiding in plain sight.

According to the Minor Planet Center, ED138 takes about 281 years to orbit the Sun, ranging from 36.86 Astronomical Units (AU) at its closest approach to 49.04 AU at its farthest.

Its orbit is also tilted by roughly 24.5 degrees relative to the rest of the solar system — a prime example of the orbital quirks that make these objects so hard to track. Most planets sit on a relatively flat, disc-like plane called the ecliptic. Because of this, astronomers focus the majority of their telescopes on this narrow band of the sky.

An object tilted by 24.5 degrees spends most of its time high above or far below this standard viewing zone, hiding where traditional surveys aren’t routinely looking.

Researchers plan to decipher if the strange orbits are caused by a prodigal planet or a swarm of rocks. Either way, Holman says “Rubin will image the whole southern sky again and again, so any others hiding in the places earlier surveys skipped are now within reach.”