Pluto nicknamed as “puzzling planet” or “runaway planet” was discovered by Clyde Tombaugh, a young US astronomer at the Arizona Lowell Observatory in 1930[footnoteRef:1]. Pluto is the largest known “dwarf planet” and the ninth largest object direct orbiting the sun. It’s the coldest, smallest and most distant planet from the sun. Similar to other Kuiper belt objects, the landscape of Pluto is mainly rock and ice. Astronomers have remained puzzled with the origin of Pluto for centuries with earlier work suggesting that Pluto is a residual planetesimal. [1: Tombaugh, Clyde, and Patrick Moore. 1980. Out of the Darkness; The Planer Pluto. Harrisburg: Stackpole Book]
There are varied hypothesis on Pluto’s origin such as the possible knocking out of Pluto by Neptune’s largest moon Triton implying that Pluto didn’t possess a fully planetary status. The concept was later rejected as subsequent research established that there is no interaction of Neptune’s and Pluto’s orbits[footnoteRef:2]. Another strand of hypothesis argues that the formation of distant rocky core in the Sun’s protoplanetary disc resulted in the emergence of Pluto.  J. Hunter Waite Jr and Christopher Glein theory of the formation of Pluto referred to as Cosmo chemical model argue that Pluto is a giant comet containing gas and ice. According to Ley. The discovery of Pluto dates back to early 19th Century with the discovery of Uranus by Sir William Herschel which was beyond Saturn that for centuries had been recognized as the outermost planet. Urbain Le Verrier’s exploration of the existence of Neptune following the perturbations identified in the Uranus orbit further increased the interest of exploration that led to the discovery of Pluto [footnoteRef:3]. Theorizing that the puzzling perturbations in Neptune and Uranus orbits, the founder of the famous Arizona Flagstaff Observatory Percival Lowell posited the existence of gravitational influence of an unknown planetary body, proposing the existence of a ninth planet named as Planet X. [2: Ley, Willy. 1956. The Demotion of Pluto. New York : Galaxy Publishing Corp.] [3: Tombaugh and Moore. 1980. ]

Lowell search for Planet X began in 1903 but died in 1916 before finding Planet X after 13 years of dedication to mathematical theory and planet search. Fortunately, Lowell had left sufficient work on the mathematical theory implying the remaining task is purely observational search. Having left a strong observatory team, the search for Planet X continued until the recording of an exceptional object on the search plates on 21st, 23rd, and 29th January and subsequently in February...…only takes 8.6 minutes for sunlight to travel from the sun to the Earth. The planet has a radius of 715 miles (1151 km) and a size equivalent to 1/6 of the Earth width. Given Pluto’s great distance from the sun and its faintness, it took 48 years to ascertain its nature[footnoteRef:7]. [7: NASA Science. 2019. Solar System Exploration. April 25th. Accessed April 27, 2019. https://solarsystem.nasa.gov/planets/dwarf-planets/pluto/in-depth/.]

Pluto was considered the 9th planet until 2006 when The redefinition of characteristics of the planet by the International Astronomical Union (IAU) in 2006 demoted Pluto into “dwarf planet”. IAU defines a dwarf planet as "A celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit."[footnoteRef:8] Most of the discoveries on planet Pluto had remained results from observations. It’s until 2015 when exploration of Pluto began after the launch of New Horizons spacecraft in 2006 providing a detailed snapshot of the prevailing atmosphere in Pluto[footnoteRef:9] [8: NASA Science. 2019. ] [9: Stern, S, F Bagenal, K Ennico, and George Gladstone. 2015. "The Pluto system: Initial results from its exploration by New Horizons."…