Did you hear that now we have an eight-planet Solar System? Because of the discovery of many objects similar to Pluto in the late 20th and early 21st centuries, in 2006 the International Astronomical Union defined the term "planet" for the first time. Pluto failed to meet the requirements and was reclassified as a dwarf planet. Pluto was counted as the Solar System's ninth planet for 76 years - from the time of its discovery in 1930 to 2006.
