What defines a planet? | Physics homework help
From its discovery in 1930 up until 2006, Pluto was considered the ninth planet in the Solar System. After the International Astronomical Union revised and solidified the definition of a planet, poor Pluto was demoted to “dwarf planet,” with the discovery of similar icy bodies beyond Neptune. A similar reclassification occurred for Ceres in the 19th Century.
Do you think Pluto should still be designated a planet, or not? What about the other four classified dwarf planets? Consider the IAU definition and the characteristics of both planets and small bodies in the Solar System, and defend your position.