The sun along with the eight planets, the moons, and other heavenly bodies form the solar system. Our solar system is a part of the milky way galaxy. The sun is at the centre of the solar system around which all other planets rotate. Except Mercury and Venus, remaining six planets have their natural satellite revolving around them in a particular orbit. In our solar system, Earth is the only planet having life. This is due to the hostile conditions available in it. Sun is the ultimate source of energy for sustenance of life on the Earth.