Still moving stuff over from my last server. Here is one that keeps coming up.
Surprisingly, I STILL get comments and questions from students and teachers about Pluto. Questions such as:
- “Why do scientists hate Pluto?”
- “How did they discover that Pluto was not a planet”
- “What will happen to our planet songs without Pluto?”
- “Why does Goofey wear clothes, but Pluto doesn’t even though they are BOTH dogs?”
Here is the explanation I like to give. I like to start with the following question:
Suppose you were outside and saw this (image from wikimedia):
What would you call it? Some might call it a tree, others might call it a bush. Does the name change what it is? What if scientist came up a classification for determining if something was a bush or a tree. According to wikipedia, there is not complete agreement on the definition of a tree. This is ok, because the name of something isn’t really that important.
That is the point, Pluto is like a green leafy plant that some would say is a bush and some would say is a tree. To make things clear, scientist have created the following definition of a planet. A planet is an object that meets the following requirements:
- Orbits the sun (this is ok for Pluto)
- Large enough to be spherical (this is also ok for Pluto)
- The most massive object in its neighborhood of the solar system (this is where Pluto fails).
Pluto fails the last criteria because it is in the area of Neptune (sometimes it is even closer to the Sun than Neptune). Thus, alas, Pluto is not classified as a planet. It shall be called a dwarf planet.