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.
Answer preview
The discovery of Eris, which was seen as slightly larger than Pluto, made the need to reclassify objects that were large enough to be spherical but had not cleared their orbits greater. Therefore, in August 2006 during the IAU general assembly, the definition of planets was revised to exclude objects that had not cleared their orbits and the term “dwarf planet” was introduced for objects similar to Pluto (Margot, 2015). In conclusion, the debate of whether Pluto should still be considered a planet is still ongoing, but with the above facts in mind, I strongly consider Pluto and others like it dwarf planets.
