Pluto is a dwarf planet orbiting in the outer part of the solar system, in the Kuiper belt. Discovered by Clyde Tombaugh in 1930, it was considered the ninth planet in the solar system for 76 years.
Pluto is the sixteenth largest and seventeenth largest celestial body mass in the solar system, and is the largest of the dwarf planets. Its mass and size are smaller than those of the major natural satellites of the solar system. Pluto is primarily made up of ice and rock.
Its orbit is rather eccentric and inclined with respect to the plane of the ecliptic, while its distance from the Sun varies from 30 to 49 AU.
On July 14th, 2015, the New Horizons probe became the first spacecraft to fly over Pluto, making detailed measurements and observations of the dwarf planet and its moons. In September 2016, astronomers announced that the reddish-brown cap covering Charon’s north pole is composed of tolines, organic macromolecules that may be ingredients for life.