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Pluto

Pluto is a dwarf planet in the Kuiper belt, a ring of icy bodies orbiting beyond Neptune. Originally discovered in 1930 and considered the ninth planet, Pluto was reclassified in 2006 when astronomers adopted a new definition that excluded small, ice-based worlds. It is the ninth-largest and tenth-most-massive object orbiting the Sun. Pluto orbits 30 to 49 astronomical units from the Sun and has five known moons, with Charon being the largest. The NASA New Horizons spacecraft provided our first close-up views during its 2015 flyby, revealing Pluto's diverse terrain of craters, mountains, and glacial features. This distant world matters because understanding Pluto and the Kuiper belt helps scientists learn about the formation and composition of our Solar System.

Sources

• en.wikipedia.org: “Pluto (minor-planet number 134340) is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune.”
• en.wikipedia.org: “It is the ninth-largest and tenth-most-massive known object to directly orbit the Sun.”
• en.wikipedia.org: “Pluto was discovered in 1930 by Clyde W. Tombaugh, making it the first known object in the Kuiper belt.”
• en.wikipedia.org: “In 2006, the International Astronomical Union (IAU) formally redefined the term planet to exclude dwarf planets such as Pluto.”
• en.wikipedia.org: “Pluto has five known moons: Charon (the largest and the diameter of which is just over half that of Pluto), Styx, Nix, Kerberos, and Hydra.”
• en.wikipedia.org: “New Horizons was the first spacecraft to visit Pluto and its moons, making a flyby on July 14, 2015, and taking detailed measurements and observations.”