In comparison the definition of a planet, as defined by the International Astronomical Union in 2006 is “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 neighbourhood around its orbit.” (IAU)
Therefore, the principle difference between a dwarf planet and a planet, and the reason behind Pluto’s distinction as a dwarf planet, …show more content…
earth is thought to share its orbit with thousands of near-earth asteroids (NEAs). However, other scientists such as astrophysicist Steven Soter say consideration must be given to the objects relative to the planet whose orbit it shares. Soter has put forward an idea to measure a planet’s orbital neighbourhood, called the planetary discriminant, and concludes that Earth, unlike Pluto, is 1.7 million times the mass of all other objects in its orbit and therefore, has a ‘clean’ orbital neighbourhood in that none of the objects sharing its orbit have the gravitational force or weight to alter the planets orbit. (Wilkins, A)
In summary, the topic of dwarf planets and the classification in regards to orbital neighbourhoods which makes Pluto a dwarf planet are still topics of