Eris

Eris is the Greek goddess of strife and discord, a figure in ancient Greek mythology. In Hesiod's Theogony she is usually described as a daughter of Nyx, embodying strife and rivalry and influencing human affairs. She is best known for allegedly sparking the Judgment of Paris by sending a golden apple inscribed “to the fairest” among Aphrodite, Hera, and Athena, an act that helped precipitate the Trojan War. In Roman mythology her counterpart is Discordia. Eris is associated with conflict, competition, and misfortune, and her myth has been interpreted in various literary and artistic traditions.

In astronomy, Eris is the name of a trans-Neptunian object and dwarf planet discovered in 2005 by Mike Brown and others at Palomar Observatory. Named after the mythological goddess, Eris is one of the most massive known dwarf planets and lies in the scattered disc beyond Neptune. It has an elongated, inclined orbit with a semi-major axis around 67–68 astronomical units and a orbital period of about 563 years. Its diameter is about 2,300 kilometers, making it roughly Pluto-sized, though more massive. Eris has one known moon, Dysnomia, named after the daughter of Eris in Greek myth, representing lawlessness. In 2006 the International Astronomical Union classified Eris as a dwarf planet, a designation that arose during discussions of planetary status prompted by Eris and similar bodies.