The traditional view of the solar system consisting of nine planets orbiting the Sun is outdated. We are now informed that there are eight planets and five dwarf planets orbiting our star.

The need to redefine the definition of a planet became significant with the discovery of Pluto’s “twin” in 2003. Discovered by Mike Brown, Chad Trujillo and David Rabinowitz, this object was larger than Pluto and was initially touted as the tenth planet. It was originally given the nickname “Xena” (and its moon “Gabrielle”) after the Fantasy TV series, before being officially named “Eris”, the Roman goddess of strife & discord.

Before the resolution was amended, Pluto & Eris would both have qualified as planets together with potentially hundreds more Kuiper Belt objects (KBOs). It was clear that any definition that allowed for hundreds of planets needed changing.