via Livescience, the confusion of astronomers about the definition of planet and the subsequent impact on the status of the solar object called Pluto has left American school chidren (and probably children and adults globally) pretty confused. Traditionally accepted as a planet since its discovery in 1930, the International Astrnomical Union redefined the world as a "dwarf planet" two years ago, only to recently coin yet another term for it and object like it, "plutoid".
"Science teachers and publishers already worked to update their resources to read "dwarf planet." And now, boom, that category is out of favor among astronomers.
"Students who have just learned about the concept of dwarf planets must now be taught the new concept of plutoid," said Janis Milman, who teaches earth science at Thomas Stone High School in Maryland. "This will lead to confusion in the classroom and resistance to learning the new terms, because the students will question, why learn something that might change again in a year or so?"
This has left educators and textbook manufacurers scrambling to keep up and everyone scratching their heads, and has left even some astronomers vowing to keep up the good fight to maintain Pluto's status as a planet. The difference between a dwarf planet and a plutoid appears to be simply location: plutoids are small rocky/icy objects located outside the orbit of Neptune, so recently discovered Kyper Belt Object Eris is also a plutoid, leaving the object Ceres (formerly an asteroid) as the only true "dwarf planet" - even my head is spinning and I follow this stuff pretty closely.
Stay tuned for further developments.