The document discusses the discovery of the dwarf planet Eris. In 2003, astronomers Mike Brown, Chad Trujillo, and David Rabinowitz discovered an object they initially called 2003 UB313 that was later named Eris. Eris is over 25% more massive than Pluto and orbits further from the sun. Its discovery reignited the debate around what defines a planet. In 2006, the International Astronomical Union officially designated Eris as a dwarf planet along with Pluto, defining a planet as clearing its orbit. Eris' moon was named Dysnomia, the goddess of lawlessness in Greek mythology.