Randy Culp, age 11, of Williamston, Mich., for his question:

CAN THE SUN REALLY BURN WITHOUT OXYGEN?

This must be true, for the sun has little oxygen and there is little or no oxygen out there in space. Yet our blazing star burns brighter and hotter than any ordinary fire we know on the earth. Our ordinary fires need to use a steady supply of oxygen, or they stop burning. The sun does not.

Scientists suspect that the sun is a nuclear furnace, related to our nuclear power plants and atomic bombs. None of these fiery blasts need oxygen to make them burn. They are powered by nuclear energy, which happens when the nucleus of the atom is changed. The sun's energy is nuclear fusion, which occurs when the nuclei of hydrogen atoms fuse to create atoms of helium.  Some of the fragments are left over, and this material is converted into nuclear energy.