Worked out according to the Commission definition, planets are considered only celestial body orbiting the Sun, with sufficient gravity to have a shape close to the field and occupying its orbit alone. Thus, in the solar system has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
Dwarf planets would be Pluto, Charon (formerly known as Pluto), the asteroid Ceres, revolving between the orbits of Mars and Jupiter, and the objects of so-called Kuiper Belt Xena (Xena, object UB313) and Sedna (object 90377), which are further away from the Sun than Pluto.
Pluto was officially recognized as a planet by the International Astronomical Union in May 1930. Then it was thought that it is much larger in size.
“Life would be much easier if we have only eight planets and many interesting small objects in the solar system – says Brian Marsden (Brian Marsden), director of the Minor Planet Center of the IAU. – Do not get me wrong, I’m not opposed to Pluto, it is very interesting . But there are a lot of interesting things. “