Tony Dick, age 12, of Ramer, Alabama, for his question

How fast does the earth rotate?

The spinning earth rotates on its axis; bringing us day and night as we turn toward and away from the sun. We divide each calendar day into 24 hours, so you would think that it takes the earth 24 hours to complete each rotation. It is true that our time system is based on the earth's motions, but actually the matching job is not perfect. Each rotation really takes about 23 hours and 56 minutes, roughly four minutes less than 24 hours.

Our globe, of course, rotates as a solid unit and the entire surface completes each rotation in harmony. However, the surface is a curved sphere and the latitudes rotate at different speeds. The bulging equator spins the fastest, a trifle faster than 1,000 miles per hour. From here the rate decreases as the surface curves toward the poles. At these pinpoints, there is no rotation. Halfway between the poles and the equator, the surface rotates at about 500 miles per hour. A half mile from the exact poles, the surface takes the usual 23 hours and 56 minutes to dawdle around a circle one mile wide.