One argument often used in favor of demoting Pluto is the fact that another planet was discovered beyond Pluto and that with many more possible small planets in the Kuiper Belt, we could end up with "too many planets" in our solar system. Well, there is no such thing as too many planets. At one point, we thought Jupiter had four moons. Now we know it has 63, and more may be found. Should we limit the number of moons because otherwise, there will be too many to memorize? Should we limit the number of elements in the Periodic Table because kids won't be able to memorize that many? The fact is, memorization is not a very useful learning tool. At one point, we knew little more about the planets than their names and order from the Sun. That is not true today. It is more important that kids understand what distinguishes the different types of planets.
If we use the alternate, broader term that a planet is any non-self-luminous spheroidal body orbiting a star--which many planetary scientists prefer over the IAU definition--we can then use subcategories to distinguish the types of planets. While we previously recognized two subcategories, the terrestrials and the gas giants or jovians, the new discoveries show us there is a third class-the dwarf planets. These are planets because they are large enough to be rounded by their own gravity--a state known as hydrostatic equilibrium--but of the dwarf subcategory because they are not large enough to gravitationally dominate their orbits. In fact, Dr. Alan Stern, who first coined the term "dwarf planet," never intended for dwarf planets to not be considered planets at all. If this one area is amended so the IAU resolution establishes dwarf planets as a subclass of planets, much of the controversy would evaporate.
