Eris

Eris is a dwarf planet located in the Kuiper Belt beyond Neptune, approximately 96 astronomical units from the Sun. It is similar in size to Pluto but has a more eccentric and inclined orbit. Discovered in 2005, Eris is composed mainly of ice and rock, and it has a highly reflective surface. Its reclassification as a dwarf planet in 2006 helped define what qualifies as a planet, emphasizing that Eris shares key features with Pluto but does not clear its orbital neighborhood. Eris’s discovery added to our understanding of the diverse objects populating the outer solar system.