Planet Nine and inclination, of objects scattered outward by Jupiter and Saturn, leaving some of them in high inclination (inc > 50°), low eccentricity orbits which have not been observed. The gravitational influence of Planet Nine would explain five peculiarities of the Solar System: While other mechanisms have been offered for many of these peculiarities, the gravitational influence of Planet Nine is the only one that explains all five. The gravity of Planet Nine also excites the inclinations of scattered disc objects, which in numerical simulations leaves the short-period comets with a broader inclination distribution than is observed. The clustering of the
Definition of planet then-accepted planet, Pluto. In its August 2006 response, the International Astronomical Union (IAU), recognised by astronomers as the world body responsible for resolving issues of nomenclature, released its decision on the matter during a meeting in Prague. This definition, which applies only to the Solar System, states that a planet is a body that orbits the Sun, is massive enough for its own gravity to make it round, and has "cleared its neighbourhood" of smaller objects around its orbit. Under this new definition, Pluto and the other trans-Neptunian objects do not qualify as planets. The IAU's decision has not resolved