Todd Nanney, age 10, of High Shoals, North Carolina, for. his question:

What is the total weight of the earth's atmosphere?

The total weight of the earth's airy shell is estimated to be 5,700 million million tons. In round numbers, that figure is 57 plus a tail of 14 zeros. The air around us seems to weigh nothing at all. It seems logical to wonder whether some heavier material on high must be adding to the total weight of the atmosphere. No    all of it is made of gaseous air, mixed with an assortment of dusty particles. What's more, the air on high gradually grows much thinner and lighter than the layer that sits on the ground.

True, the weight of the atmosphere seems enormous. But the solid planet below it is far, far heavier. The air in a box one foot square weighs only 1 1/4 ounces. But the size of the earth's atmosphere is immense, much larger than the vast oceans and even larger than the solid planet itself. And every cubic foot of its volume adds a little something to its enormous total weight.