Suppose there existed a planet that went around the Sun twice as fast as the earth. What would be its orbital size as compared to that of the earth?
Time taken by the Earth to complete one revolution around the Sun, Te=1 year Time taken by the planet to complete one revolution around the Sun,TP=21Te=21 year Orbital radius of the planet = Rp From Kepler’s third law of planetary motion, we can write: (ReRP)3=(TeTP)2 (ReRP)=(TeTP)2/3 =0.5(2/3)=0.63 Hence, the orbital radius of the planet will be 0.63 times of the Earth.
