Pluto was reclassified as a "dwarf planet" in 2006 by the International Astronomical Union. Although it orbits the Sun and is spherical, it doesn’t clear its orbital path of other debris. This distinction separates it from the eight major planets.

Despite its smaller status, Pluto is still fascinating, with icy mountains, a nitrogen-rich atmosphere, and possible subsurface ocean. NASA’s New Horizons mission provided the first close-up images of this distant world