Reference image
Object guide
Eris is a massive scattered-disk object and one of the most massive known dwarf planets. Its discovery was a major driver in the redefinition of 'planet' by the IAU in 2006. Eris is approximately 2,326 km across.
How to observe Eris
Eris is generally a challenging visual target. Use a current ephemeris, dark skies, and image stacking when its angular size or brightness is insufficient for direct detail.
Scientific context
Useful scale comparisons are 0.183 Earth diameters, 0.084 g surface gravity, 558.056 Earth years per orbit. These values are rounded from the catalogue measurements shown on this page.
- Radius
- 1,163 km
- Diameter
- 2,326 km
- Mass
- 1.66E+22 kg
- Mean density
- 2.519 g/cm³
- Surface gravity
- 0.82 m/s² (0.084 g)
- Orbital period
- 203,830 days (558.056 years)
- Semi-major axis
- 67.7 AU
- Mean sunlight travel time
- 563.04 minutes
0.183 Earth diameters0.084 g surface gravity558.056 Earth years per orbit
Source: NASA Science (checked 2026-08-09). Values are rounded catalogue measurements.
Interactive orbit model
Aug 13, 2026, 22:251×
Calculated positions / separate exploration scales