Discovered on 18 February1930 by Clyde Tombaugh, Pluto was originally classified as the ninth planet from the Sun. However, its status as a major planet fell into question following further study of it and the outer Solar System over the ensuing 75 years. In 2006, IAU (International Astronomical Union) released new definition of planet, with which Pluto was stripped of its planethood and reclassified as a member of the new “dwarf planet” category.
In 2015, Pluto will be visited by a spacecraft for the first time. NASA’s New Horizons will perform a fly-by of Pluto system and take detailed measurements of Pluto and its moons.
