Randy scott, age l0, of huntsville, ala., for his question;
What is moonlight made of?
It bathes the sleeping world with a wash of ghostly glimmers. It pokes beckoning fingers through our windows and transforms the outdoors into an unearthly wonderland. This magical moonlight makes any young person curious to know more about it.
Every up to date student knows that solids, liquids and gases are made from particles of matter called atoms and molecules. Maybe we take it for granted that even such things as energy are made from the same ingredients. Science, however, is full of upside down paradoxes, and in the case of energy this notion is both true and untrue. For matter is a sort of frozen state of energy.
Energy can be converted or changed into matter, and matter can be converted into energy. In the hydrogen bomb, atomic particles of matter are converted into nuclear energy. Moonlight starts forth as this same kind of nuclear energy, and after a couple of space trips it lands on the earth. It is created in the nuclear furnace of the sun, where every second 4 million tons of matter are converted into radiant solar energy.
The sun s radiant energy fans out at the speed of light, and after 8 minutes of travel time small portions fall upon the earth and the moon. It is a blend of light, radio and other forms of electromagnetic energy, all pulsing along on their own wave lengths. Some wave lengths of solar energy shed light on the moon, and some are changed to heat and absorbed by the lunar landscape. About 7% of the moon's quota of solar energy is reflected out into space. We see it as moonlight.
This reflected solar energy also travels at the speed of light. It takes l.28 seconds to reach the sleeping earth from the moon. We would expect this secondhand sunshine to be weaker than direct sunshine and so it is. It would take the light from 650,000 full moons to equal the daytime sun. And even the immense dome of the sky is too small to hold so many moons.
The ratio of sunlight reflected by a heavenly body is called its albedo. Some areas of the lunar surface are better reflectors than others. Its over all albedo is 7%. Compared with the earth's albedo of 30%ythe moon is a very poor mirror that keeps 93% of its quota of solar energy.
As a mirror, the earth is l3 times bigger and much brighter than the moon. Some of its reflected sunshine reaches the moon. The earthlight shed upon the moon is 60 times brighter than the moonlight shed upon the earth. We often see this earthlight as a dim glow on the dark area of the new moony and we call it the old moon in the new moon's arms.