-Michael R. Meraz, age 10, of Visalia, California, for his question:

What is meant by the Tropic of Cancer?

We borrowed the word "cancer" from the ancient Romans. It was their name for a crab. They named a certain constellation Cancer because it looks like a leggy crab. Around June 22, we get our longest days and the noon sun rises its highest. Farther south, about 1,600 miles north of the equator, it climbs directly overhead. At that time of year, the sun happens to be surrounded by the sprawling stars of Cancer the Crab. They cannot be seen because the sun out dazzles them.

The place where the sun is overhead at noon on the longest day is called the Tropic of Cancer. It is a thin line that circles all around the globe, level with the equator and about 1,600 miles farther north. At that time and in that place, the noon sun is exactly overhead with Cancer the Crab.