Alex Fernandes, age 12, of Fontana, California, for his question:

How did almanacs come about?

Human beings can invent almost anything. As a rule, they tend to invent things when they need them or want them very, very badly. Our remote ancestors were in need of almanacs because they were farmers, and farmers must keep track of the changing seasons of the year. An almanac is a way of keeping track of what happens from year to year. In earliest times, this job was done by astronomers who watched the changing skies through the seasons. In ancient Egypt, when Sirius rose with the sun, the astronomers knew that the Nile would soon flood. It was time to sow the crops. The earliest almanacs were records of the seasonal changes in the parade of heavenly bodies over the sky.

These almanacs proved themselves very useful. So as time went on they were im¬proved. People kept records of each day's weather through years and years. If stormy winds arrived every March, they noted this on their almanacs. They figured out the phases of the moon for the year ahead and added this data also. As time went on, an almanac became a very detailed document with all sorts of predictions for the days ahead. Most of these predictions turn out to be true because they are based on what has happened on certain days through many years in the past.