How much brighter is sunlight than moonlight?
Sometimes the moon seems as big as a melon and most of us think that it occupies a bigger circle of sky than the sun. But our eyes are deceived by the size of the moon in the sky because it is a bright spot surrounded by the darkness of night. If you cut a disk one fifth of an inch wide and hold it two feet away from your eye, you will be surprised to find that it completely covers the round face of the full moon and seen from the earth, the sun seems to occupy exactly the same sized area of the sky.
The sun, of course, is a blazing star and even on a cloudy day it sheds enough light for us to see clearly as far as the horizon. The moon is a cold, barren sphere which sheds no light of its own. But, like the earth, it too is bathed in the golden glory of light from the sun. The half of the moon which happens to be facing the sun is in daylight, just as the half of our globe which happens to be facing the sun is in daylight.
The part of the moon which is turned away from the sun is hidden from our eyes in the shadows of night. We see the golden light of the lunar day creep over the side of the moon facing us the new moon$ the half moon, the full moon and the new moon again.
The amount of light shed by the moon depends somewhat upon how much of its daytime side is facing us. We get the most moonlight when the moon is full and the side facing us is entirely in daylight. However, we do not see all of the light which falls upon the lunar landscape, The surface of the moon is rough and dark and for this reason it absorbs most of its sunlight.
Only about seven per cent of the sunlight falling upon the moon is reflected out into space and this is the light which washes over our world as moonlight. It is but seven per cent of the sunlight which falls on an area only one eighth the area of our globe. Yet this pale light has been estimated and compared with the dazzling daylight which falls upon the earth.
It would take, we are told, 465,000 full moons to equal the daylight poured upon the earth by the sun. Even if the moon were willing to multiply itself to give us that amount of light, the job would be impossible. All those full moons would fill the entire visible sky, not once but several times.
Some areas of the rough, rocky face of the moon reflect more sunlight than others and this is why we see shadowy blotches on the full moon. The dull, flat plains called lunar seas reflect less light than other areas and the center of the round ball at full moon tends to reflect the most light. The moonlight which reaches us, 465,000 times paler than sunlight, comes from an average blend of these different areas.