James Todd, age 9, of Costa Mesa, Calif., for his question:

How did the signs of the zodiac come to be?

Our dizzy old earth spins around in a vast ocean of space, with countless stars stretching far and wide in all directions. We see only a few of them, depending on our view of outer space. In Southern California, you can face the sea and turn around to face the mountains. Our view changes as we turn to face a different direction. The same thing happens as the dizzy earth turns to face this view, then another view of the starry slay.

The spinning earth is tilted as it orbits around the sun. During its yearly orbit, it is tilted to face a special circle through the starry heavens. This circle is called the zodiac  and it happens to be a ring of 12 starry groups called constellations. Through the year they change with the passing months. In olden days, people called them the signs of the zodiac, perhaps because they were signs of the changing months.