Pluto has always been my favorite planet. Yeah, yeah, I know that for the moment, according to the International Astronomical Union, Pluto isn’t technically a planet but a minor planet.
The reasons given for declassifying this enigma of the solar system are that Pluto’s orbit is far too eccentric compared to the other planets (it soars above the others and even cuts into Neptune’s for 20 years of its estimated 248-year orbit around the sun, and it doesn’t “clear” a path of its own.
Well, for that matter Neptune couldn’t be considered its own planet since Pluto invades every 20 years; during Pluto’s intrusion from 1979-1999 (while Pluto was considered the ninth planet), Neptune was technically the farthest planet from the sun. Besides, Neptune-like Uranus, Saturn and Jupiter-is a non-terrestrial gas giant. In other words, under the clouds it is one giant ocean of various gases. Many scientists feel that Jupiter isn’t so much a planet as it is a failed star. Jupiter back in the nineties had a collision with a comet-so much for clearing its own path. Mars’ moons have large craters that indicate collisions with asteroids. Mars does have craters in it also. That doesn’t sound like clearing its own path. Earth gets meteor showers from time to time, and there are craters on both the earth and the moon. That doesn’t sound like clearing its own path, either. Mercury also has craters, as does Venus. So, if you REALLY wanted to break it down, there are no true “planets” in our solar system.
I really think the classification should’ve waited until Pluto is visited in the next decade, when we’ll finally get good close-up images and learn more about this fascinating world. I was a bit perplexed by the IAU’s decision, since a few years ago I e-mailed them about this and received a response strongly suggesting that Pluto is a planet and that the matter was indefinitely closed.
Some argue that only a fraction of eligible voters actually voted when the IAU voted in 2006 in Prague. They meet again in Rio de Janeiro in 2009, and some, including Astronomy magazine, speculate that Pluto may regain its status. Many in the field of astronomy say the current ruling is vague, elitist and highly subjective.