Susan Boles, age 13, of Morristown, nd., for her question:

What is inside the earth?

Our globe is almost 8,000 miles in diameter, which means that the center of the earth is nearly 1,000 miles beneath our feet. We live on the outer crust of the earth, a layer of rocks which enfolds the globe like a thin orange peeltu The crust is between 30 and 50 miles thick. No living thing exists more than a few miles above or below sea level, No one has tunneled to the bottom of the earth s thin crust. Our knowledge about the interior comes from such things as earthquake vibrations.

The crust rests upon a heavier layer of rocks some 600 miles thick. This is the outer mantle and it rests on a still heavier layer which is about 1,200 miles thick. Below this is the earth's care, a dense and seething ball of heavy metals. The dense core, about 4,000 miles in diameter, is wrapped in lighter and lighter layers of rock which enfold it like the skims of an onion,