Questions in this quiz: Dwarf Planets — Pluto and Beyond

The 2006 IAU reclassification. Pluto and Charon, the New Horizons flyby, plus Eris, Haumea, Makemake, Sedna, and the trans-Neptunian region. Why Pluto isn't a planet anymore.

1. In what year did the International Astronomical Union adopt the formal definition of 'planet' that excluded Pluto? — Options: 2003, 2006, 2009, 2012
2. Which NASA spacecraft performed the first close flyby of Pluto? — Options: Voyager 2, Cassini, New Horizons, Dawn
3. According to the IAU's 2006 definition, which criterion did Pluto fail to meet? — Options: Orbiting the Sun, Having sufficient mass to be roughly spherical, Having cleared the neighborhood around its orbit, Possessing at least one natural satellite
4. The discovery of which object in 2005 was a major trigger for the debate that led to Pluto's reclassification? — Options: Eris, Sedna, Haumea, Quaoar
5. What is the name of Pluto's largest moon? — Options: Nix, Hydra, Charon, Styx
6. The region of icy bodies beyond Neptune that contains Pluto and many similar objects is most commonly called what? — Options: The Oort Cloud, The Kuiper Belt, The Asteroid Belt, The Heliosphere