The word planet has long existed and has a relationship of history, science, mythology, and religion. By ancient civilizations, the planet was seen as something that was immortal or representative of gods. As advances science, man's view of the planet changes.
In 2006, the International Astronomy Association (IAU) passed an official resolution defining planets in the Solar System. This definition is praised but also criticized and is still debated by a number of scientists because it does not include objects with planetary mass that are determined by the place or object of its orbit. Although eight planetary objects discovered before 1950 are still considered "planets" according to modern definitions, a number of celestial bodies such as Ceres, Orcus, Juno, Vesta (each object in the Sun asteroid belt), and Pluto(the first discovered trans-Neptune object) that was once considered a planet by the scientific community is no longer a planet.