Facts about Eris's 2005 discovery
- 08
Astronomers initially mistook Eris for a tenth planet in 2005 because its extreme distance of 96 AU made it appear dimmer than Pluto despite being significantly larger.
- 07
Eris's moon Dysnomia, discovered in September 2005, orbits the dwarf planet every 15.8 days at a distance of approximately 37,400 kilometers.
- 06
The initial observation of Eris used a telescope at Palomar Observatory in California to detect the distant dwarf planet through its unusually high reflectivity caused by a surface of frozen methane and nitrogen.
- 05
Eris's discovery photograph in 2005 revealed an unexpectedly bright object due to a highly reflective surface of frozen methane and nitrogen, giving it the highest albedo of any known dwarf planet.
- 04
Eris orbits the Sun once every 557 Earth years at a distance averaging 96 astronomical units, making it one of the most distant known objects in our solar system.
- 03
Eris's discovery in the outer solar system triggered the International Astronomical Union to formally define what constitutes a planet, resulting in Pluto's demotion in 2006.
- 02
Mike Brown's team at Caltech initially designated Eris as planet 2003 UB313 before its official naming in September 2006, sparking the debate that led to Pluto's reclassification.
- 01
On January 5, 2005, astronomers at Palomar Observatory discovered Eris, a dwarf planet larger than Pluto at 2,326 kilometers in diameter.