Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory in Flagstaff. Here's how Pluto won - and lost - its planetary ...

Pluto fails the third criterion because its orbit overlaps with objects in the Kuiper Belt, a region of icy bodies beyond Neptune. So, a new class of celestial object — the dwarf planet — came ...

The cosmos is filled with wonders yet to be discovered. One of the latest mysteries captivating scientists and space ...

Arizona in 1930 and was considered our ninth planet until 2006. The International Astronomical Union reclassified Pluto as a dwarf planet because it does not clear its orbit of other debris.