Eris
Dwarf Planet
Eris is one of the most massive known dwarf planets, covered in highly reflective frozen methane. Its discovery in 2005 directly triggered Pluto's reclassification, since Eris is nearly as large and forced astronomers to define 'planet' more precisely.
Field Notes
- Eris's 2005 discovery directly led the IAU to formally define 'planet' in 2006, reclassifying Pluto as a dwarf planet.
- It is nearly as massive as Pluto despite being slightly smaller in diameter.
- Its highly reflective surface, coated in frozen methane, makes it one of the brightest objects in the outer solar system.
| Planet Specifications | |
|---|---|
| Radius | 1,163 km |
| Mass | 1.660 × 10²² kg |
| Distance from Sun | 10.12B km |
| Rotation Speed | 27.3 km/h |