When I was a lad Pluto was a PLANET!

It is relatively recently, 2006, when International Astronomical Union (IAU) agreed the definition of Dwarf Planet and re-categorised Pluto as one of these rather than as a Planet. The first 5 Dwarf Planets are named Ceres, Pluto, Haumea, Makemake and Eris. Eris is, in fact, more massive than Pluto. This Dwarf Planet categorisation has been controversial with many different strong views held amongst the astronomical community. Estimates of the number of objects that could be classified as a Dwarf Planet vary greatly but around 50 are generally accepted to be ‘likely’ with 10 of those ‘nearly certainly’.

Basic Data

NASA Dwarf Planets Pages

NASA Pluto Factsheet