Grossman, age 9, of Montreal, Quebec, Canada, for his question:

How is a sun made?

Our clever scientists don't know everything, but they know enough to make some pretty good guesses. Nobody is positive how a starry sun is created. But there is a lot of evidence to make a good guess. Astronomers are just about certain that a blazing sun started out as an enormous cloud of thin gases. Then the thin gases began to crowd together, though nobody knows why. As this happened the big fuzzy cloud began to shrink.

As the gases grew thicker and more crowded, the young sun grew smaller and smaller. It began to swirl and spin around. Most likely some of the material around its edges gelled to form planets. Meantime the crowded gases in the central sun grew hot    and hotter. At last the starry sun was hot enough to start its nuclear furnace. Then the fiery furnace shed light and heat on all its planets. Most likely this is how our sun got started  • about five billion years ago.