Roland Van Heest, age 13, of St. Louis, Mo., for his question:

WHAT IS A QUASAR?

A quasar is a galaxy that gives off a tremendous amount of energy from its central core. Energy is delivered .in the form of light and radio waves. The word is a shortened form of the term quasistellar radio source.

Some quasars are near the edge of our universe. Ready for a big number? It will take light 10 billion years to travel from such quasars to the earth, and that is traveling at the speed of 186,282 miles per second.

A quasar will release about 100,000 billion times as much energy as does the sun. Astronomers aren’t sure how the quasar generates so much power, but some believe the energy is the result of a collision between fast moving stars or the explosion of stars called supernovae.