Christine Obermeier, age 11, of Lucas, Iowa, for her question:

WHY MUST A COMET POINT ITS TAIL AWAY FROM THE SUN?

The seething sun radiates enormous energies in all directions. Some of this is in the form of mini charged particles that stream forth as the solar wind. This high speed solar wind has enormous pushing power, especially close to the sun. A comet is a small bundle of rather loose debris that makes a close U turn around the sun.

As it nears the sun, a comet faces into the solar wind. Gases and other loose particles are pushed backward to form a tail that streams along behind its bright head. During its close U turn, it swings around to depart in another direction. The solar wind then becomes a tail wind, pushing the comet's gauzy tail ahead of its head. Coming and going, the tail is pushed away by the solar wind that streams outward from the sun.