The earth and moon have different rotation rates. The earth rotates once every 24 hours while the moon rotates around the earth once every 27.3 days. The moon’s rotation is coupled to the earth’s rotation primarily through the ocean tides. The moon is gaining energy from the earth’s rotation while the earth’s rotation is gradually slowing. What will be the length of one earth day when the earth and moon finally reach equilibrium? How far will the moon be from the earth? What fraction of initial energy is lost to friction?