Manny Meneakis, Age 10, Of Gary, Ind., for his question:

Why must a navigator know astronomy?

There are no landmarks way out on the wide and lonely ocean. But overhead is the starry sky, and the stars move in an orderly parade over the heavens. Every hour, day and night throughout the year, the bright constellations are always in their proper places. A navigator needs no landmarks when he knows the positions of the stars.

He also uses the reliable old sun to chart his way over the ocean. He uses tables to determine the sun's path every day; and when it reaches its highest point, he knows that the time is noon. In a small way, we use astronomy to find direction when we point to Polaris to show us which is north. When we know this, we can then figure out all the other directions.