Welcome to You Ask Andy

Mary Catherine Robison, age 13, of Oceanside, California, for her question:

When were quasars discovered?

Man has always looked at the stars and our scholarly ancestors began charting the heavens more than 5,000 years ago. They kept accurate records of what they saw but they saw nothing beyond the range of human vision. In 1609, Galileo looked at the heavens through a telescope. For more than three centuries, man's celestial view depended on bigger and better telescopes. Then about 40 years ago, the radiotelescope was invented. It scanned a far wider range and revealed celestial objects that nobody suspected were there    including quasars.

It is not easy to astonish astronomers. They are used to observing fantastic heavenly wonders. But when the first quasars were discovered in the late 1950s, even the astronomers were astonished. The discovery was first announced to the world of science by the Mullard Radio Astronomy Observatory at Cambridge. An intense source of radio emissions was identified in the celestial catalog of 1959. Radio telescopes swept vast reaches of the heavens, gathering pulsing radio energies from far and wide. At first, no one could pinpoint this intense radio source.

Light and radio waves are forms of electromagnetic energy, whipping across cosmic distances at the same tremendous speed of 186,000 miles per second. Their energies pulse along on different wave lengths. Telescopes gather wave lengths of visible light. Radio telescopes gather invisible radio waves, sweeping across wider ranges and probing further into the heavens.

Through more than 300 years, astronomers used telescopes to assemble countless photographic plates showing pinpoints of light from distant stars. Since the 1930s, radio telescopes have been used to assemble celestial pictures of cosmic broadcasting stations. All stars emit radio energies as well as visible light. Pictures from radio telescopes and light telescopes are compared to learn more about the nuclear activity of the stars. But the cosmic broadcaster found in 1959 was emitting 100,000 million times more radio energies than our average, starry sun. Finally its direction was narrowed down. The 200 inch telescope at Palomar identified the radio source as coming from a faint, faraway star.

Astronomers knew that no ordinary star could broadcast such energy. They called it a quasi star, meaning star like object, and quasi star became quasar. Probing its secrets began at once. In the next few years, 200 more quasars were discovered by radio telescopes and pinpointed by optical telescopes. These strange objects broke all the known laws and challenged former ideas about the universe. The average quasar may be more than 10 million times more massive than our sun. A small quasar could engulf several solar systems, a large one could engulf most of the stars we see in our sky, including the space between them. The most powerful quasars emit almost as much radio energy as galaxies and astronomers estimate they can broadcast through at least 100,000 years. All of them are billions of light years from the earth and traveling at fantastic speeds. Obviously quasars are not ordinary stars or anything like them. They break far too many of the usual star regulations. Astronomers have suggested theories, but so far no one can definitely explain them or their role in the heavens.

The known quasars are named with numbers and letters. The speed of quasar 3C 9 was clocked in 1965. It was traveling out toward the edge of the known universe at 140,000 miles per second    almost 8000 times faster than the sun and its planets whirl around the Galaxy. The radio impulses from 3C 9 reached us from across 9,000 million light years. The quasar emitted them 9,000 million earth years ago    and where it is at this point in time, nobody knows.

 

PARENTS' GUIDE

IDEAL REFERENCE E-BOOK FOR YOUR E-READER OR IPAD! $1.99 “A Parents’ Guide for Children’s Questions” is now available at www.Xlibris.com/Bookstore or www. Amazon.com The Guide contains over a thousand questions and answers normally asked by children between the ages of 9 and 15 years old. DOWNLOAD NOW!