The whole debate as to whether Pluto should be considered a planet started when an astronomer from Caltech, Mike Brown, discovered the "tenth planet," Eris. Eris was slightly bigger than …show more content…
In order to determine whether this is a classification that should be adopted, we must ask: is this classification useful? The requirement that a planet be round is a factor in whether geological and planetary processes can occur, and so is a useful distinction. The requirement that a planet clear other objects of its orbit is, I think, also a useful classification. Studying how different celestial bodies interact with each other is an important part of both muggle and magical astronomy, and so distinguishing bodies based on how they interact with the objects around them is useful. Furthermore, the small number of bodies that can be classified as a planet according to this stricter definition is itself informative. Since so few bodies are planets, it shows that the bodies which do pass all of the criteria are unique in some way. The successful vote of the IAU to take on these definitions also indicates that it is the consensus of experts in the field that this is a useful classification to