Quote: Elfie - 2010.12.10. 13:39:47 I was tought the planets in elementary school. But please, check yourself and let me know if I'm the one who is wrong here and the question is correct: http://nineplanets.org/
Keep searhing...In of August 2006, at a meeting of the International Astronomical Union, Pluto was voted to be demoted from planet status to "dwarf planet" because it and its moon are part of a sea of other objects that occupy the same region of space.
From a news article:
The word "planet" originally described wanderers of the sky that moved against the relatively fixed background of star. Pluto, discovered in 1930, was at first thought to be larger than it is. It has an eccentric orbit that crosses the path of Neptune and also takes it well above and below the main plane of the solar system.
Recent discoveries of other round, icy object in Pluto's realm have led most astronomers to agree that the diminutive world should never have been termed a planet.