Explanations:
A light- free celestial body orbiting the star is called a Planet. There are the bodies from the sum which orbit the sun in their respective orbit and are illuminated by the sun's light. The number of planet in our solar system is eight. Ascending order of planets according to density (in increasing order)- (1) Saturn (2) Uranus (3) Jupiter (4) Neptune (5) Mars (6) Venus (7) Mercury (8) Earth.