Hobbies And Interests
Classification
The IAU's 2006 classification system divides objects orbiting a sun into three categories: planets, small solar system bodies and dwarf planets. Like a regular planet, a dwarf planet must be large enough for its own gravity to shape it into a sphere. Unlike a regular planet, the dwarf is too small to clear other objects out of its orbital neighborhood. This is important because the astronomers recognized celestial bodies massive enough to become spheroids can be found among asteroid fields.
Pluto and Eris
In 2005, Eris, a spheroid object larger than Pluto, was found in the Kuiper belt, the scattered asteroid belt beyond Neptune. Astronomers debated whether Eris would be classified as the 10th planet of the solar system or if they needed a new classification system. They chose the latter, and declared Eris and Pluto dwarf planets. Astronomers had argued since the discovery of Pluto in 1930 if it should be classified as a planet. The discovery of Eris was a transition point for this debate.
Distinct Celestial Bodies
Dwarf planets are large enough to maintain atmospheres, yet the surrounding asteroid fields in which they exist may significantly impact the dwarf's outer surface. Astronomers acknowledge these spheroidal, atmospheric celestial bodies can survive among asteroid fields without major disruption. The discovery and classification of dwarf planets enable astronomers to study the relationship between them and the asteroid fields.
Planetary Astronomy
Planetary astronomy evolved into a major field of study after an extra-solar planet was discovered around the star 51 Pegasi in 1995. One problem was how to define planets now since the previous standards of having a spheroid shape and orbiting a sun were no longer enough. The classification of dwarf planets was an important step in the field's development. They represent the possibility of more spheroidal objects orbiting among the Earth's asteroid fields.