Final answer:
The solar system is divided into inner and outer regions by the Asteroid Belt, located between Mars and Jupiter, at roughly 2.7 AU from the Sun. The inner region consists of rocky terrestrial planets, while the outer region contains the gas and ice giants.
Step-by-step explanation:
The solar system is roughly divided into inner and outer regions by an invisible line known as the Asteroid Belt. This region is located between the orbits of the planets Mars and Jupiter. One way to define the separation between the two regions in terms of number is to use the average distance from the Sun to the Asteroid Belt, which is about 2.7 astronomical units (AU). One AU represents the average distance from the Earth to the Sun, roughly 150 million kilometers (93 million miles).
The inner solar system contains the terrestrial planets which are comprised of Mercury, Venus, Earth, and Mars. These planets are made mostly of rock and metal. Beyond the Asteroid Belt lies the outer solar system, where the gas giants like Jupiter and Saturn, as well as the ice giants Uranus and Neptune, can be found. These planets formed in cooler parts of the solar system and accumulated their large gaseous envelopes, enabling them to grow to their massive sizes.