Pluto: Diary of an Ex-Planet

This eBook short read (12,000 words) tells the story of this fascinating little world on the edges of the Solar System: from its discovery in 1930 by American astronomer Clyde Tombaugh to its controversial demotion to 'dwarf planet', and the renewed interest of planetary scientists as its secrets were finally unlocked, following the spectacular 2015 flyby of Pluto by NASA's New Horizons space probe. Among the discoveries were that although Pluto's atmosphere is a near-vaccum, there are weather systems with significant effects on surface features. Pluto may also experience cryovolcanism - eruptions of cryogenic fluids and slurries rather than silicate magma. Small though Pluto is, it hosts five known moons. The largest of these, Charon, is significantly larger than the dwarf planet Ceres. The surface to suface distance from Pluto to Charon is just 18,000 km, only slightly more than the flight distance between the United Kingdom and Australia. No other comparably sized Solar System bodies are so close. From one side of Pluto, Charon hangs motionless in the sky, never rising nor setting; from the other side, it is never seen at all. Prior to 2006, the Pluto-Charon system was often described as a binary planet. *Depending on Pluto's distance from the Sun, light takes 4 hours (when at perihelion) and 6 hours 50 minutes (when at aphelion) to make the trip. For comparison, it takes light just over eight minutes to reach Earth from the Sun. *To boldly go: A small portion of Clyde Tombaugh's ashes were carried aboard the New Horizons space probe, which became the first and so far only spacecraft to visit Pluto. To date, only a handful of human remains have been sent into space, and no others have travelled any further than the Moon. *Gustav Holst was an early Pluto-sceptic. His seven-movement The Planets: Suite was composed during World War I, and it included all the then-known planets apart from Earth. Pluto was discovered four years before Holst's death, but he declined to compose an additional movement. In 2000, Manchester's Hallé Orchestra commissioned the English composer Colin Matthews to write an eighth movement, which he called 'Pluto, the Renewer'. The movement was dedicated to Holst's daughter, composer Imogen Holst, who died in 1984. *The Walt Disney cartoon dog Pluto the Pup was named after Pluto and not, as is sometimes believed, the other way round. *The radioactive element plutonium (Pu), which can be used in the manufacture of nuclear weapons, is named after Pluto. It followed Neptunium (Np), named after Neptune, and Uranium (U), named after Uranus. *Following Pluto's demotion, a new word entered the vocabulary: To pluto is to demote or devalue someone or something. Late in 2006, the American Dialect Society voted 'plutoed' as its Word of the Year.