Greg Gr1ewe, age 7, of Grinnell, Iowa, for his question:

How can the sun burn without oxygen?

This question is very troublesome to young space agers. It is not easy to grasp the difference between a star and a planet. Our sun is a star and we live on the planet earth. The sun is a seething ball of blazing gases. The earth is a cool ball of solids, liquids and gases. Our cozy log fires would seem cool on the seething sun. But we earthlings are used to them and we know that our kind of everyday fire cannot burn without oxygen gas to help it.

If the sun burned logs and coal, it would soon turn to ashes. But it is a different kind of fire. It is an atomic furnace somewhat like a never ending hydrogen bomb. Its heat comes from hydrogen atoms changing into helium atoms. This kind of atomic energy needs no oxygen. The sun is a whopping nuclear furnace.