The New Horizons spacecraft was launched in 2006, and will arrive at Pluto in 2015. It will be the first spacecraft to visit that very distant dwarf planet.

Pluto, located on the outskirts of our solar system, has a different kind of mountain range, made up of ice. The ice mountains are about 11,000 feet tall. The New Horizons spacecraft spotted them for the first time when it flew by the dwarf planet in July 2015.

After Pluto and Eris, Makemake is the third largest dwarf planet.

Pluto was reclassified as a dwarf planet.

In 2006, Pluto was declared as a dwarf planet.

Eris, the largest known dwarf planet, was first detected in data collected in October of 2003.

Eris is the largest known dwarf planet in our solar system. It is a little larger than Pluto.

In 2006, the International Astronomical Union decided to create a new category for solar system objects called "dwarf planets", and Pluto was reclassified as a dwarf planet.

Over the past few years we've discovered several dwarf planets. One of them, Eris, is even bigger than Pluto.

The closest dwarf planet to Earth is Ceres.