Discovered in 1930, Pluto has long been considered the ninth planet of our Solar System. However, after the discovery of similar worlds in the Kuiper belt, it has been reclassified as dwarf planet.
Pluto is smaller than the Moon, and lies about 5,8 billions km from the Sun. It has a thin atmosphere, mainly composed of nitrogen, methane and carbon monoxide. On average, the temperature of Pluto is -232°C, and this makes it an icy planet.
Pluto’s surface is characterized by mountains, valleys, plains and craters. In this photo a heart-shaped glacier is clearly visible.