The Plutonic Problem

Pluto Gets the Boot

PRAGUE, Czech Republic (AP) — Leading astronomers declared Thursday that Pluto is no longer a planet under historic new guidelines that downsize the solar
system from nine planets to eight.

Ok so yea, there is a little public outcry, but if you actually get down to the nuts and bolts of it this is a good decision. And I’ll (briefly) explain why.

Pluto was found in 1930. It took so long to find because it is really small compared to all the other classical planets in our solar system, in fact is is even smaller then our own moon! For comparison on what this means in Earth terms, our moon has approximately the same Land Area as Africa in terms of square miles. That means Pluto is, essentially, smaller then one of Earth’s continents.
Pluto’s orbit is also at a weird angle compared to that of the inner planets. To visualize, think of a dinner plate. Now put 8 peas, or cherries, or grapes on that plate in a line stretching from the center of the plate to the outer edge. If you were to spin that plate on its center point you would have a very basic model of how the classical planet’s orbits look. They revolve around the sun in the same “plane” Now take a Hula Hoop and put it around the dinner plate, but don’t lay it flat. Instead, you will need to prop one end of the hula hoop up about 2 feet. This is Pluto’s orbit. In scientific terms, Pluto’s orbital plane is tilted 17 degrees off of the System’s ecliptic plane.

One other thing to make note of, Pluto is not alone way out on the edge of our solar system. 2 years ago astronomers found another object that is even bigger then Pluto, and further away. This would be fine, except the region this object was found, and the region of space which is also occupied by Pluto, is known as the Kuiper belt (pronounced Kie-per). The Kuiper Belt is an area filled with small and medium sized chunks of ice that were leftovers from the formation of our system. The problem with calling Pluto a planet, is that the Kuiper already has over 1000 known objects that are regularly tracked by telescopes, and it is probably that it has up to a million objects that just haven’t been discovered yet.

If we call Pluto a planet, what do we call all the objects out there in the same orbital plane and the same general region of space? Do we increase the number of “known planets” in the Solar System to over 1000, or a million? Pluto has been a labeled as a planet since it was found, but in reality this is less then 100 years. In my view we are simply refining our definition based on new evidence. When Pluto was found, nobody knew about the Kuiper Belt. A better understanding of how things work often requires a re-classification of how things are labeled. Remember, in Galileo’s day the Earth was the center of the universe and everything in space was the exact same distance away attatched to a giant sphere known as the firmament, beyond which lay heaven and the gods. Where would we be if the scientific community refused to update their definition?

Speaking of which, the “definition of a planet” as decided by the IAU will very likely be revised as there are terms that don’t make sense. But the exclusion of Pluto as a classical planet will probably remain, and I think rightly so.
Ok I know I said “briefly” but come on, you guys know me. This is brief