John Williams, age 12, of Radcliffe, Kentucky, for his question:

Does the earth have phases in the lunar skies?

Andy's sensible pen pals know that nobody is 100 per cent perfect all the time  not even a small pixie. Several alert readers wrote polite notes pointing out that he was all wrong about the earth phases as seen on the moon. So he was    and thank you each and all. Let's hope that today's column sets things right again. John's question was selected because his correction came first  ¬and it was expressed with courtesy. That last detail counts a lot, especially in times of embarrassment.

Andy answered a similar question a year ago    and got it right. The same topic came up just when the astronauts landed on the moon. Like everybody else, your faithful reporter got carried away in the historic excitement. This time he got the answer wrong. However, being a bit space happy is no excuse. Merely an explanation. Let's hope that today's corrected answer puts those phases in their proper places once and for all.

From 93 million miles out in space, the radiant sun beams down on both the earth and the moon. However, both these celestial bodies are round globes and the sun shines only on half of each globe at a time. The earth and moon behold each other across about 240,000 miles of space. And they see the areas that are bathed in golden sunlight. In both cases, the golden areas change because the moon insists on orbiting around and around the earth. During every lunar month, the moon beholds a complete series of changing earth phases and we behold a series of changing moon phases.

This occurs because the orbiting moon keeps changing its position in relation to the earth and the sun. Once during every lunar orbit, it gets more or less directly between us and the sun. The side facing away from us is bright with sunlight and the side facing us is shrouded in darkness. However, at this time the moon sees only the sunlit side of our globe. We lose sight of the dark old moon while the full earth shines in the lunar skies. The earth and the moon phases are reversed as they pace together through the lunar month.

Two weeks after the Full Earth Phase, the moon has swung around to the opposite side of its orbit. Now the earth is between the moon and the sun. Our side of the lunar globe is bathed in golden daylight.. However, the earth's daylight side is turned   away from the moon. While we behold the Full Moon Phase, the Old Earth Phase appears fn the lunar sky. As the moon orbits on its way, it sees the New Earth, the half and three quarter phases. While this goes on, we see the Full Moon wane through its three quarter and half phases. There is one odd feature in this heavenly hoedown. The same side of the moon always faces the, earth. The rotating earth presents all sides of the globe to the moon in the course of every 24 hours. We see the golden phases creep, across the same lunar landscape. From the moon, the earth's geography rotates through the sunlit areas every calendar day.

The moon also rotates. But its leisurely spin equals the orbiting period of the lunar month. This is why we never see the other side of the moon    and the other side never sees the earth. The rotating earth gives every part of our globe a chance to see the lunar phases with every calendar day. However, the earth phases are never seen from the far side of the moon.