Up until very recently the icy rock has been a mystery, but since the flyby of New Horizons, more information than ever before is now known about Pluto. The flyby was long awaited, as the distant dwarf planet Pluto was first discovered by Clyde Tombaugh eighty-five years earlier in 1930.
Despite the discovery of Neptune in 1846, the irregularities in the orbit of Uranus remained unexplained. A number of astronomers speculated that a ninth planet was the cause of this. First attempts to find a possible ninth planet were made by founder of the Lowell Observatory, Percival Lowell, from 1905 to 1909. Using data from the observations of Uranus’ orbit, Lowell was able to estimate where in the sky the ninth planet could be. Using a number of different telescopes, Lowell searched the sky for Planet X. He estimated locations of the planet and published them in the ‘Memoir on a Trans-Neptunian Planet’ in 1915. A year later he passed away, with no sighting of the mysterious planet.
Eleven years later the search resumed. Percival’s brother Abbott Lowell took control of the search, and hired Clyde Tombaugh to operate the new 13-inch telescope. Tombaugh began searching in 1929 for the ninth planet in the region that Lowell had identified, but was unable to locate the mystery planet. Tombaugh decided that Lowell’s predictions were wrong, and began scanning the entire sky for movements indicative of a planet. On February 19, 1930, Tombaugh discovered Pluto, finally putting an end to the work that Lowell had started 25 years earlier.
Following the discovery of the ninth planet, astronomers around the world were in celebration. Using the findings, orbits were calculated and the planet’s place in our Solar System was understood. Names began flooding in, with Lowell’s wife Constance suggesting it be named after her husband. In the end, the name Pluto was chosen, after a suggestion by Venetia Burney, an eleven year old schoolgirl from England. Pluto is the Greek god of the underworld, which was considered appropriate for the dark, mysterious world on the edge of the Solar System. It was officially proposed on May 1, 1930.
The first moon of Pluto to be discovered was Charon in 1978. The moon, which measures 648 miles (1043 km) in diameter, orbits just 12,200 miles (19,640 km) from Pluto. Charon’s orbit around Pluto takes the same amount of time as one Pluto rotation. This means that Charon always hovers over the same spot on the surface of Pluto, and the same side of Charon is always facing Pluto – tidal locking. Pluto’s four other moons were discovered by Hubble in the last decade. Nix and Hydra were discovered in 2005 by scientists in preparation of the New Horizons mission, and the smallest moons Kerberos and Styx were discovered in 2011 and 2012 respectively.
It was only until July 2015 that the Pluto system was finally revealed, with the flyby of the NASA spacecraft New Horizons. The mission brought an end to the mystery which shrouded the dwarf planet’s existence, and uncovered incredible information about Pluto and its five moons.