Description: Eight of the nine planets in our solar system fall into two groups called the inner planets and the outer planets. The four planets closest to the Sun are called the inner planets. They are Mercury, Venus, Earth, and Mars. The inner planets are also called the rocky planets, because they are made mainly of rock and iron. There are four outer planets: Jupiter, Saturn, Uranus, and Neptune. The outer planets are also called the gas giants because they are huge and made mainly of gas. Pluto, the farthest planet from the Sun is a small ball of ice. Some astronomers wonder whether Pluto should be called a planet.
    

Description: Eight of the nine planets in our solar system fall into two groups called the inner planets and the outer planets. The four planets closest to the Sun are called the inner planets. They are Mercury, Venus, Earth, and Mars. The inner planets are also called the rocky planets, because they are made mainly of rock and iron. There are four outer planets: Jupiter, Saturn, Uranus, and Neptune. The outer planets are also called the gas giants because they are huge and made mainly of gas. Pluto, the farthest planet from the Sun is a small ball of ice. Some astronomers wonder whether Pluto should be called a planet.