Pluto is a small planet that revolves around the Sun in the outermost orbit of the Solar System at 3.67 billion miles (5.907 billion km) away from this star, having the largest eccentricity. Located in the Kupier Belt, it takes this planet 248 years to complete an orbit around the Sun. Being the smallest in size of all the planets of the Solar System, Pluto has a diameter of 1,400 miles (2,300 km) and about 0.8 % of the Earth mass. It is composed of frozen gases, such as nitrogen and methane, and a small solid rocky nucleus. Pluto was discovered in by Clyde W Tombaugh in 1930, an amateur astronomer.