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
Planet the Drake equation, which estimates the number of intelligent, communicating civilizations that exist in the Milky Way. There are exoplanets that are much closer to their parent star than any planet in the Solar System is to the Sun, and there are also exoplanets that are much farther from their star. Mercury, the closest planet to the Sun at 0.4 AU, takes 88 days for an orbit, but the shortest known orbits for exoplanets take only a few hours, e.g. Kepler-70b. The Kepler-11 system has five of its planets in shorter orbits than Mercury's, all of them much more massive