Terry Mitchell, age 10, of Liberty Lake, Washington, for his question:

Exactly how does the earth rotate?

Picture an enormous ball that measures about 25,000 miles around the outside. This is the planet Earth. Now picture it rolling along, much as a ball roils along the ground. As it rolls, it spins or rotates around its axis, which is a line straight through the middle from pole to pole. In a general way, this is the motion of the earth's rotation    except for one difference.

The earth does not roll like a ball on the ground. It is Out There    surrounded by vacant space on every side. To stop from falling into the sun, it races around and around its orbit. And as it orbits the sun it rotates around its axis, once around every 24 hours. It rotates towards the east. So the sun and the stars out there in space keep rising and coming into view above the eastern horizon.