Astronomers Spot a Potential New Pluto-like Dwarf Planet in Our Solar System

WHO:

Mashable - The Vera C. Rubin Observatory discovered 2026 ED138, described as a dwarf planet candidate.

Wired - Astronomers are working to confirm whether 2026 ED138 meets the criteria for a dwarf planet.

WHAT:

Yahoo Tech - Early estimates put 2026 ED138 at about 600 to 1,500 kilometers (370 to 930 miles) across; its size is estimated from its distance, brightness, and presumed surface reflectivity.

Yahoo Tech - The object was found in more than 20 observations from Rubin images captured between March and July.

Yahoo Tech - Rubin’s earlier testing and optimization work yielded more than 11,000 previously unknown asteroids, including 33 previously unknown near-Earth objects that posed no threat to Earth, and hundreds of objects beyond Neptune.

Yahoo Tech - The observatory submitted around 1 million observations to the International Astronomical Union’s Minor Planet Center, covering more than 11,000 unknown asteroids and over 80,000 known objects.

Yahoo Tech - Rubin is expected to produce about 30 million gigabytes of data over its lifetime.

Mashable - Scientists think they have discovered a new dwarf planet like Pluto.

Wired - 2026 ED138 is a possible new dwarf planet in the solar system.

Wired - 2026 ED138 could be as large as 1,500 kilometers in diameter.

WHERE:

Mashable - 2026 ED138 is beyond Pluto.

Wired - 2026 ED138 lies beyond Pluto.

WHY:

Yahoo Tech - 2026 ED138 appears near the plane of the Milky Way, where the large number of stars can make moving objects difficult to identify.

Mashable - Scientists explain how 2026 ED138 had remained hidden from them.

(UPDATED October 29, 2026 16:05 UTC)

The Vera C. Rubin Observatory has discovered 2026 ED138 beyond Pluto, a possible dwarf planet that astronomers are now working to confirm. Early estimates suggest it may be about 600 to 1,500 kilometers across, though its size is uncertain because it’s estimated from its brightness, distance and presumed surface reflectivity. The object appeared in more than 20 Rubin observations, and its position near the crowded plane of the Milky Way made it difficult to spot among the stars.

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(UPDATED October 29, 2026 10:02 UTC)

The Vera C. Rubin Observatory has discovered 2026 ED138 beyond Pluto, a possible new dwarf planet that could be as large as 1,500 kilometers across. Astronomers are now working to confirm whether it meets the criteria for a dwarf planet, like Pluto. Scientists are also explaining how the object remained hidden from them.