Jill Finley, age 11, of Eureka, Calif., for her question:

HOW BIG IS THE UNIVERSE?

The universe is made up of all the matter, light and other forms of radiation and energy that have been discovered by man. The universe also consists of everything that man believes to be prastnt somewhere in space and time as a result of the universe.

More than 100 billion stars are grouped in the shape of a giant circular galaxy called the Milky Way. The Milky Way is about 100,000 light years across. A light year is the distance that light travels in a year: about 5.88 trillion miles.

To show how big the universe is, consider this fact: studies tell us that there are at least as many galaxies in the universe as there are stars in the Milky Way. That means more than 100 billion galaxies, each one about 100,000 light years across.