Thomas C. Bates, age 13, of Charlotte, North Carolina, for his question:

Do We know what caused the ice ages?

No one can say what caused the grim glaciers of the ice ages to advance and retreat over the earth. We may, however, make a guess. The educated guess of a well informed expert is called a theory. There are several theories concerning the cause of an ice Age, but none has been proved right or wrong.

The cooler climate of an ice Age might be caused by dust in the atmosphere, perhaps from massive volcanic activity. Dusty air shuts off some of the sun's heat. Another theory suggests that the sun's output may vary enough to cause a cooling of the earth's climate. This theory may be proved right or wrong as science learns more about the nature of our starry sun.