another tiny dot, another large possibility

October 29, 2026

Diagram comparing dwarf-planet candidate 2026 ED138’s orbit with the outer planets.

Read Rubin Observatory’s account of its first dwarf-planet candidate.

Rubin Observatory has found 2026 ED138, a possible dwarf planet hiding in the outer solar system. “Possible” is doing useful work here: finding the object and establishing exactly what it is are separate jobs.

The observatory’s images track its movement against a dense field of stars. The orbit diagram supplies the other half of the story: a tiny mark in a photograph can belong to something substantial, very far away. Space remains inconsiderate about scale.

Read the observatory’s account rather than upgrading a candidate into a confirmed planet in the headline.

Featured image: NSF–DOE Vera C. Rubin Observatory/NOIRLab/SLAC/AURA; image processing M. Jurić (UW), D. de Martin and M. Zamani (NSF NOIRLab). Orbit diagram: NSF–DOE Vera C. Rubin Observatory/NOIRLab/SLAC/AURA/R. Proctor; image processing M. Zamani; orbit data IAU Minor Planet Center; star map NASA/Goddard SVS; Gaia DR2 ESA/Gaia/DPAC. Images via Rubin Observatory, CC BY 4.0 under its media policy; displayed at reduced size.