Craig Clemons, age 12, of Sarasota, Fla., for his question:
HOW DID WE GET THE FOUR DIRECTIONS?
The four major directions, called the cardinal points of the compass, are north and east, south and west. If you stand in the middle and measure an equal distance in each of these directions, they form the corners of a perfect square. They were invented ages ago by travelers who wanted to plot their journeys.
Our earliest ancestors, roaming in search of food, most likely depended on landmarks such as rivers, valleys and distant mountain peaks. As game animals migrated north and south, early man became aware of the seasons. Then another human quality entered the picture.
Long before recorded history, people noticed the starry constellations and how some of them change with the seasons. Often they named them for their favorite animals. They also noticed certain year round constellations, always circling around the sky. They named one of these the Big Bear we call it the Big Dipper and it still gives the clue to the four major directions.
As the Big Dipper circles the sky, the two stars in the bowl opposite the curved handle always point to a star that does not move. It is Polaris, the North Star. When you face toward it, south is behind you. East is on your right side and west on your left.
Most likely this is how our remote ancestors first figured out the four cardinal points of the compass. Nowadays we know that the stars appear to move because the earth rotates and the poles are the two ends of its axis. The poles themselves do not rotate, and the North Pole points steadily to Polaris.
Much later the magnetic compass was invented, and its needle pointed northward day and night. We now know that one end of its little magnet points to the north pole of a great magnet inside the earth. This area is the magnetic pole and some distance from the North Pole axis. So the magnetic compass is not quite perfect. But neither is the North Star. It is a short step from the true north. What's more, the earth is slowly shifting to point to a different North Star.
During seagoing days, the face of a mariner's compass showed 32 directions, with extras added between the four major points. A modern compass has 16 major directions based on the 360 degrees of a circle. In aviation, the magnetic needle is replaced by more dependable gyroscopes. But all these refinements began with Polaris, the Pole Star.