Jeffrey White, age 14, of West Warwick, Rhode Island, for his question:
What caused the craters on the moon?
Just a few weeks from now, the whole world expects to witness the most stupendous event in all human history. One day in this coming month of July, the first human beings plan to stand on another world another celestial globe in the heavens. This is something, really something to think about, even though this other world is only our familiar moon.
When you go to a show, it is a good idea to have a program, or at least learn a bit about what to expect. Otherwise the details rush by and escape you. None of us want to miss all the details of the historic flight of Apollo 11. Our newspapers and TVs will provide programs in advance. But some of you will get even more from the great event from the details behind the scenes. For example, we know that there are questions that only a lunar landing can answer. One of these is the riddle of the lunar craters.
The Apollo space missions have taken mankind nearer and still nearer to the surface of the moon. They have given us detailed pictures of the lunar landscape its flat seas, its bumpy mountains and its craters, craters, craters. Scientists have been trying to solve the riddle of those lunar craters for ages. And right now, on the eve of the first lunar landing, no true scientist will state that he can prove how they were formed.
However, there are two possible theories, or educated guesses. There is evidence to support each theory. But there are unexplained details that do not quite fit into either picture as we now see it. One is an outside theory, the other an inside theory. The outside theory suggests that the craters were formed by meteorites of assorted sizes. A vast number of solid meteors are space traveling through the Solar System. Those that strike the earth are mostly consumed on their way down through our atmosphere. But the moon has no atmosphere and meteors must whack down with full force.
This explanation seems plausible. Over sized meteors have whacked similar big round craters on the face of the earth. However, there are strange rills, ridges and other features associated with the lunar craters. At present no one is quite sure how or if these fit into the meteorite theory.
The inside theory suggests that the craters may have been caused below the lunar surface. Some of those round cavities resemble volcanic craters on the earth. True, the modern moon appears to be a peaceable body, not given to volcanic high jinks. However, reliable observers have reported rosy glows on the moon. If true, this might indicate that the lunar landscape is not as dead as it looks. In any case, its past geological history may have paralled that of the fiery young earth. Before its hot interior settled down, it may have erupted through the cooling outer crust, time and again. Most of the evidence of the earth's early upheavals has been erased by wind and weather and restless seas. But there were no seas or weathery atmosphere to erase similar evidence from the face of the moon. The lunar craters may have been formed by volcanos, billions of years ago.
Naturally, our astronauts will not relay the answer to this question the moment they land on the moon. The solution requires patient, expert study. So the astronauts plan to gather and bring back about 50 pounds of moon minerals. Earth scientists can tell a great deal about the geological past from samples of this sort. And they are just as curious as you are about those tantalizing lunar craters. Let's hope they solve this old problem so that our curiosity can proceed to the next fascinating mystery.