The moon is 3.9 × 10^5 km from the center of the earth. The mass of the moon is 7.3 × 10^22 kg, and the mass of the earth is 6.0 × 10^24 kg. How far from the earth's center are the gravitational forces on an object due to the earth and moon equal and opposite? (Assume the object is on the line connecting the earth and moon.)