The Solar System consists of the Sun and objects that orbit it, including 8 planets, dwarf planets, asteroids, and comets. The inner Solar System contains terrestrial planets like Earth that are composed of rock and metals. The outer Solar System contains gas giants like Jupiter and Saturn that account for most of the mass. Objects follow elliptical orbits around the Sun, with closer objects moving faster according to Kepler's laws of planetary motion. The Solar System is believed to have formed 4.6 billion years ago from the gravitational collapse of a giant molecular cloud.