Susan Levin, age 10, of Cleveland Heights, Ohio, for her question:

How did the tropics of Cancer and Capricorn get their names?

These imaginary lines which circle the earth north and south of the equator are named for a crab and a goat both made of star's. Cancer the Crab and Capricorn the Goat are two of the 12 constellations that seem to circle the earth like a belt.

During a year, the path of the sun seems to pass through each of the 12 signs, or constellations of the zodiac, in turn. At its southernmost pointy its noon rays fall straight down upon the latitudes called the Tropic of Capricorn. At its northern turning point, its noon rays fall straight down upon the latitudes of the Tropic of Cancer,

At its northern turning point, the sun appears within the zodiac against the background of Cancer the Crab, At its southern tropics or turning point, it appears within the constellation of Capricorn the Goat. The tropics on earth correspond to the tropics, or turning points, of the sun against the starry belt of the zodiac.