dwarf-planet moon · moon of the dwarf planet Eris
Dysnomia
The only known moon of the dwarf planet Eris, whose orbit allowed astronomers to weigh Eris and show it outweighs Pluto.
- Distance from Earth today
- 14.16 billion km94.67 AU · light: 13 h 7 min
- Distance from the Sun today
- 14.30 billion km95.61 AU
- As of
- 3 November 2026position from NASA/JPL orbital elements
Where it is today
Top view of the plane of Earth’s orbit, compressed distance scale. Open on the big map with the time slider →
Facts
The JPL tables do not list this moon’s parameters yet – we will add figures once they appear in open NASA/JPL data.
Discovery: 2005 – Michael E. Brown et al. (Keck Observatory)
Description
Dysnomia is the only known moon of Eris, discovered in 2005 by Michael Brown's team using the adaptive optics system of the Keck Observatory in Hawaii. Tracking its orbit let astronomers calculate the mass of Eris, which turned out to be greater than Pluto's. Dysnomia is much smaller and darker than its parent. It is named after the daughter of Eris in Greek mythology, the spirit of lawlessness – a playful reference to the actress Lucy Lawless, as Eris had been nicknamed Xena before its official naming.