Alan Kuehn, age 12, of Salt Lake City, Utah, for his question:

What happens when stars burn out?

The blazing life of a star lasts through many billions of years. But finally all its hydrogen fuel is consumed and it can blaze no more. Near the end of its glorious history the star flares up in one last spurt of blazing energy and then quite suddenly it subsides. The fires go out, and its hot gases chill to solid materials.

In the final stage of its long life a star becomes a dark ball of dead and solid material. In its early life the star most likely produced a family of planets, and these may continue to revolve around it. But when the star dies and its furnace goes out it can no longer shed light and heat upon its orbiting children. They, too, must become frozen lumps of matter traveling with it through the endless ocean of space.