Elmer Croushore, age 11, of Fairview Park, Ohio, for his question:

What is the latest news on pulsars?

The discovery of pulsars is one exciting surprise after another    and the end is not yet in sight. Andy reported their first appearance in September 1968 and promised to bring you more details as they unfolded. This column, you might say, is an interim report, which means that still more details can be expected later. Astronomers have learned a lot of fascinating facts, but as of now, they still do not know the very last word about pulsars.

In July 1967 the first known pulsar introduced itself by accident. Its beeping radio pulses were trapped by an instrument designed to gather radio waves from outer space. In January 1968 this distant radio pulsing star was named a pulsar and introduced to the world of science. Some thought that its short, repeated pulses might be intelligent radio signals from some remote world across the Galaxy. Everything about it seemed exciting and simply impossible. So naturally, astronomers around the world immediately started to solve the mystery, and thereby soothe their burning curiosity.

Recently, the American Astronomical Society met to compare notes. By now 46 pulsars have been found, measured and analyzed by every known technique. Many facts have been proven, but there have been no detailed descriptions of how a pulsar really works. When scientists are both curious and mystified, they advance educated guesses known as theories. There are several very different theories about pulsars. But in this case, the astronomers suggested that two major theories might explain two halves of one highly complex operation.

We now know that pulsars are small, high energy stars made mostly of densely packed neutrons. They belong in a class by themselves    different from the large sun types, and also different from the white hot dwarfs. They revolve apparently at fantastic speeds. They are merely a million or so years old and are burning out at a great rate. Since several are in the debris of old supernovae, perhaps some are dynamic packages left over from stars that exploded.

The basic mystery is how a pulsar creates and broadcasts its strange radio signals.

Its short signal includes a wide variety of frequencies and intensities. After a precise interval of three seconds or so, it is repeated indentically    on and on. The "near¬field theory" suggests that the emissions are generated near the surface    perhaps by charged particles speeding up from the pulsar's seething core. The "farfield theory" suggests that the emissions are related to the immense magnetic field that surrounds a pulsar. Many astronomers now suspect that factors in both theories may work together. In any case, it seems likely that a pulsar's highly complex radio emissions come from highly complex causes.

All stars are nuclear powerhouses and their dynamic operations are very complicated. The extra dynamic pulsar is new to science    and so far we are not sure how it works. Its mysterious energy exceeds ordinary stars by far. So does its magnetic field. This exceeds our sun's enormous magnetic field by several trillion times. One trillion is a thousand billion and requires a tail of 12 zeros    which gives you some idea of the peppy little pulsar's energy.