I once read from a college textbook on astronomy published in the 1880's that the Solar System was composed of 4 small rocky planets, surrounded by 4 large gas giant planets. With our current understanding of planetary formation, these 8 fit a similar pattern -- those closest to the Sun formed small and hot, those further formed large and cold. Pluto, though, is small and cold. The other abberance is that Pluto's and Uranus's orbits cross. Pluto's orbit is about 248 years, Uranus's 84, but for about 20 years, Uranus is actually further away from the Sun than Pluto! (The last cycle, by the way, ended in 1999 -- Pluto is now again further out than Uranus.) Pluto's orbit is also, unlike all other planets, not within the ecliptical plane. These orbital oddities suggests to astronomers that in times past, Pluto was actually moon of Uranus.
These two factors of size and orbit are what have disqualified Pluto as a planet. Perhaps when it was discovered back in the 1930's, the desire to add it to the family of planets was strong, being the first one discovered in nearly 100 years. We know better now.
There have been many arguments regarding whether or not Pluto is a planet. It is currently defined as NOT being a planet but instead part of what is the Kuiper belt.
Pluto is thought to be composed of mostly rock and ice. It's size is approximately one fifth of the size of the earth's moon so it is relatively small.
It wasn't until 2006 that scientists got together and actually came up with a definition for a planet and it was decided that Pluto is not one.
Many scientists still believe that Pluto should be considered a planet.
Pluto did not really die, it was just undeclared. Pluto had at first been designated as a planet. Most people grew up believing that there were nine planets and Pluto was one of them. Then about three years ago the International Astronomical Union held a series of planetary arguements in Prague. They decided to create a set of standards indicating what makes a planet a planet. Pluto did not meet their established criteria so it was undeclared.
"They pointed out that Pluto is really just a piece of debris, merely one of a swarm of icy objects out beyond Neptune called the Kuiper belt."
Pluto still exists to this day and the Illinois state governors are fighting to have it reinstated as a planet. It seems that the man who discovered Pluto was from there and they want to keep his discovery a planet.
Pluto is alive and well. We know that for sure because he does not vote in Chicago.
Ok! you are talking about which pluto, the planet one or the dog one?
The planet one did not die.
Hey u silly girl, pluto did not die it was considered not to be a planet because of its size and it does not go in a proper orbit.
I think Pluto is know classified as something else. Not as a major planet. I think it is a 'dwarf' planet or something. So it hasn't totally died! Nah, but Pluto is tooo small too be a planet. Espicially since they have found so MANY! they now need some form of classification and that means Pluto had to be kicked out!