Moonlight is primarily reflected sunlight. If the moon reflects 15% of the photons that strike its surface, and we know that the intensity of sunlight at earth is I, what is the intensity of moonlight at the Earth during a full moon? Distance from earth to moon 375x10^3 km, distance from the sun to the earth 149x10^6 km, the radius of the earth is 6,378.1 km, and the radius of the moon is 1,737.4 km.