The Sun is the only illuminated heavenly body which is actually a star in the solar system and Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto are its planets, reflecting the light received from it. All the planets are revolving around the Sun as already explained in chapter 3. The Earth is moving around the Sun under the gravitational pull of the Sun. The Moon is moving around the Earth and along with the Earth, it goes around the Sun also, under the gravitational pull of the Earth. The Moon, in turn has its own pulling force like that of the Earth.