The solar system has eight number of planets, of which four are the inner planets and four are outer planets. Within the solar system, the earth lies between Venus and Mars. Life exists on earth. It has a specific atmospheric constitution. The earth maintains an elliptical path around the sun. It completes one complete revolution once every 365 and 1/2 day. Earth is very close to the sun at the Perihelion position and at Aphelion position it is the furthest. The moon is the natural satellite of earth that constantly goes around the earth as a result of which the earth experiences alternative day and night. Thus, the earth maintains a continuous relationship with the sun as well as the moon.