The visions of Pluto in its icy form as our solar systems furthest planet no longer holds good. We now have 8 planets officially in our solar system.
Scientists have re-defined what exactly a planet is. According to the new definition, a full-fledged planet is an object that orbits the sun and is large enough to have become round due to the force of its own gravity. In addition, a planet has to dominate the neighborhood around its orbit.
Pluto is a “dwarf planet” and not an exclusive one. There are more than 40 of these dwarfs, including the large asteroid Ceres and 2003 UB313, nicknamed Xenaa distant object slightly larger than Pluto discovered last year.
Source : NatGeo