Part A Using Kepler's Law, estimate how many times greater the mass of the sun is than the mass of the earth. You can get this value by comparing the radius and period of the earth's orbit around the sun to the radius and period of the moon's orbit around the earth. The earth's orbit around the sun has a radius of 93 million miles and each orbit takes 365 days. The moon's orbit around the earth has a radius of 239 thousand miles and each orbit takes 27.3 days. (You're welcome to think about why it's not closer to 30 days!)