In 60 seconds: Astronomers have found a large, bright world far beyond Pluto — a possible sixth dwarf planet, hiding for a decade in plain sight among the Milky Way's stars. It's called 2026 ED138, and confirming it could rewrite the map of our solar system's outer edge.
- 2026 ED138 was announced October 27, 2026, by the International Astronomical Union's Minor Planet Center, from Vera C. Rubin Observatory data.
- It sits about 46 astronomical units from the Sun — farther out than Pluto — and is estimated at 600 to 1,500 kilometers across.
- It was first spotted on October 13, 2026, by astronomer Matthew Holman, then traced back through telescope images to 2016.
- It stayed hidden because it drifts across the crowded star fields of the Milky Way's plane, where moving objects are hardest to pick out.
- It is a candidate, not yet a confirmed dwarf planet — infrared observations still need to pin down its size and shape.
Here's the thing: for ten years, telescopes kept photographing a whole new world without anyone noticing. It wasn't faint, and it wasn't small. It was just lost — one more speck of light in the densest star field in the sky, exactly where astronomers almost never look for moving objects. Then, on an October evening, a search program built to connect the dots finally did.
Pluto, seen by NASA's New Horizons in 2015. The newly found candidate 2026 ED138 orbits even farther from the Sun — no close-up photo of it exists yet. Photo: NASA/JHUAPL/SwRI via Wikimedia Commons
What happened
On October 27, 2026, the NSF–DOE Vera C. Rubin Observatory announced it had found a new dwarf planet candidate in the outer solar system. The object carries the provisional designation 2026 ED138. The discovery was announced by the International Astronomical Union's Minor Planet Center and presented the same day at the American Astronomical Society's Division for Planetary Sciences meeting in Spokane, Washington.
The find came out of Rubin's early observations in Chile, taken as the observatory geared up for its ten-year Legacy Survey of Space and Time, which began in June 2026. This is Rubin's first dwarf planet candidate.
Latest verified facts
Matthew Holman, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian, found it on the evening of October 13, 2026. He was running Rubin observations through a search code he built with colleague Kevin Napier — software that links points of light seen on different nights into one moving object. One series stood out: its brightness and distance marked it as unusually large.
"My first reaction was one of excited disbelief," Holman said. "Objects like this are very rare, so I immediately started checking whether I or the code had done something wrong."
The team then dug backward. Rubin scientist Mario Jurić found 20 more observations in Rubin's catalogs, bringing the total to 30 detections on 20 nights between March 4 and July 11, 2026. Archival Dark Energy Camera images, found through the Asteroid Institute's precovery service, pushed the trail back to 2016 — more than ten years of orbit.
The key numbers, all from the NOIRLab announcement:
| Fact | 2026 ED138 |
|---|---|
| Distance from the Sun | About 46 astronomical units (Pluto averages about 40) |
| Estimated size | 600 to 1,500 kilometers across — in Makemake and Haumea territory |
| Orbit tilt | Almost 25 degrees off the plane of the solar system (a "hot classical" Kuiper Belt object) |
| Status | Candidate only — infrared observations are needed to confirm it is round and massive enough |
So why did it take so long? Two simple reasons. ED138 sits in the southern sky, where far fewer telescopes hunt for moving objects. And from our viewpoint it has spent two decades looping across the plane of the Milky Way — a wall of millions of stars that drowns out faint moving dots. As Holman put it, people don't typically search there, because it's genuinely hard to find moving objects among so many stars.
Why it matters
If confirmed, ED138 would join just five officially recognized dwarf planets: Pluto, Ceres, Eris, Haumea, and Makemake. It would be only the second new addition since 2008 — Jurić called finding something this big "something that happens maybe once in a generation."
But the discovery matters beyond the headcount. Distant icy worlds are fossils from the solar system's formation, and ED138's tilted, Neptune-disturbed orbit is exactly the kind of clue that tests how the giant planets migrated billions of years ago. And the way it was found — by re-mining data that already existed — previews what's coming: Rubin will photograph the whole southern sky again and again for a decade, and Holman says any other worlds hiding where earlier surveys skipped are now within reach.
Impact on the USA and the world
Rubin is an American flagship — funded by the National Science Foundation and the Department of Energy, operated by NOIRLab with SLAC — and its early results are already paying off. In April, before the survey formally started, the Rubin team submitted observations of more than 11,000 new asteroids, including roughly 380 new trans-Neptunian objects, to the Minor Planet Center. ED138 is the headline act of that haul.
There's a practical angle too: ED138 is bright enough, Holman says, that "really capable amateurs can see it if they know where to look." You won't spot it with the naked eye, but backyard astronomers can actually chase this one.
What happens next
Our take: don't expect a naming ceremony tomorrow. The next step is infrared observation, which will narrow that wide size range and confirm whether ED138 is massive enough for its own gravity to have pulled it round — the key test for dwarf planet status. The public can explore its orbit in 3D through the Orbitviewer app.
Watch for two things: the infrared results, which decide whether ED138 joins the official five, and what Rubin finds next — Jurić says there may be "a handful" more objects its size still out there. The solar system's family portrait, it turns out, isn't finished yet.
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Sources: NSF–DOE Vera C. Rubin Observatory / NOIRLab announcement, October 27, 2026; CNN; Scientific American; GeekWire; ZME Science.