Ever since PBS ran The Pluto Files last month I have been trying to wrap my mind around the reason that Pluto was “demoted” from planet status. I have been thinking about the new definition of dwarf planet and it seems to me to boil down to the part of the definition that says something about the ability to "clear the neighborhood around their orbits." I ask “so what?" What is so critical about this distinction?
It seems to me that after the they discovered Eris astronomers were uncomfortable with idea of all the possible planets they might find in the Kuiper belt. What do they have against the Kuiper belt?
As a matter of semantics, “dwarf planet” still has the word “planet” in it. Doesn’t this make it a planet, subcategory dwarf? Jupiter is a big ball of gas. I think it is a failed star. Pluto is round and I could go there and put on a space suit and walk around on it.
I think the IAU is making a fine distinction that most people outside the IAU are not going to get, and therefore to most regular people does not seem necessary.
The Pluto Files—which I enjoyed and watched twice—claimed Pluto was the most popular planet, I don’t know where they got this. My vote goes to Mars.
Edit April 5
After reading some of the replies I notice a lot of people take issue with my use of the word "demoted." At first I was going to say it was a poor choice of words, I meant reclassification, but I now realize I am correct. Here why. I have two Almanacs, one from 1998 and a more recent one by the exact same company from 2007. In the 1998 one Pluto gets it own little section at the end of the group of articles for each planet. All planets are discussed equally in terms of characteristics and such. In the 2007 one, it is mentioned in a short section on the new dwarf planets which also mentions how Pluto use to be a planet. I have a recent astronomy book and Pluto is no longer listed at the end of table of characteristics of planets of the solar system section that most books like it have. I will have to look up its size, distance from the sun and ect. somewhere else. It has been demoted.
I don't have an emotional reason to keep Pluto a planet. I just find the whole issue fairly complicated and funny. I still don't understand the "clear the neighborhood around their orbits" requirement and why it makes such a big difference.