The solar system was formed 4.6 billion years ago and consists of 8 planets and is split into 3 zones, the inner solar system, the outer solar system, and the outer reaches. The inner solar system consists of 4 planets. These include Mercury, Venus, Earth, and Mars. The outer solar system consists of Jupiter, Saturn, Neptune, and Uranus. The outer reaches consists of the Kuiper belt, Heliopause, and Oort cloud. At the center of the solar system is a yellow dwarf star that we call the Sun. The planets revolve around the Sun and the Sun rotates on its own axis.