About Dysnomia
Dysnomia is the only known moon of Eris, discovered in Keck adaptive-optics imagery in 2005. Its orbital dynamics allowed the first accurate mass determination of Eris. ALMA observations in 2018 and 2023 have refined its diameter to about 700 km, making it the second-largest known dwarf-planet moon after Charon.
Physical Properties
Orbit
Gallery
Hand-picked mission imagery of Dysnomia sourced from NASA and partner archives. Click any photo for full resolution and source attribution.
Imagery on this page is provided by the original mission teams. Full attribution terms: Image Rights & Credits.
Sources & Further Reading
Numerical values (radius, mass, orbital elements, temperatures) are drawn from NASA NSSDC Planetary Fact Sheets, JPL Horizons, and the JPL Small-Body Database. Last refreshed: 2026-06-08 01:37:02.