What is a Planet?

This podcast was very informative. I found it under the K-5 section. I learned that until August of 2006 IAU reconized nine planets in our solar system, before then new studies had brought atonomers to believe that there was ten to thirteen planets out there. They had to come up with a scientific definition of what a planet is. A planet is a body that orbits a star, has enough mass to create its own gravity, has a round shape, and has cleared its neighborhood. According to this Pluto is not a planet because it crosses path with Neptune. Pluto has been reclassified as a dwarf planet. Scienitifc studies are always changing as new discoveries are made.