As director of the Hayden Planetarium, Tyson bucked traditional thinking in order to keep Pluto from being referred to as the ninth planet in exhibits at the center. He has explained that he wanted to look at commonalities between objects, grouping the terrestrial planets together, the gas giants together, and Pluto with like objects, and to get away from simply counting the planets. He has stated on The Colbert Report, The Daily Show, and BBC Horizon that the decision has resulted in large amounts of hate mail, much of it from children. In 2006, the International Astronomical Union (IAU) confirmed this assessment by changing Pluto to the dwarf planet classification.