Peter Greaves, age 10, of Salt Lake City, Utah, for his questions

What holds the rings of Saturn in place?

This story goes to show that even the most scholarly astronomers have to change their minds. Lately this has happened quite often as space probes sent back close up information from our neighboring planets. For example, the Martian landscape is not a flat, featureless desert. Giant Jupiter is not colder than cold. However, the latest information on Saturn's rings was gathered not by spacecraft, but long range radar, beamed from California's Mojave Desert.

A few years ago, most astronomers agreed that Saturns rings must be made from tiny particles, most likely of ice and dusty gases. They had good reasons to believe this was so. But in December of 1972, the popular theory was blown sky high    by a NASA 210 foot radar antenna. Using a 400 kilowatt radar beam, it bounced back signals from Saturn's rings. And we now know that these dazzling golden circles are made of sizeable chunks.

The beams left the Goldstone station in California, bounced back from Saturn and their signals came back to home base in two hours and 15 minutes. The experiment was made 12 times and each round trip was one and a half billion miles. The results were full of surprises

Radar signals echo back their signals from solid surfaces. No radar echoes returned from the planet itself. This suggests that Saturn's surface is a mass of gases, which is what everybody thought. Had the rings been made of small particles, they would have returned weak signals or none at all. Instead, they were five times stronger than,they would be from Venus, if Venus were at that distance

When the amazing signals were analyzed, astronomers learned that those glorious, mysterious rings are made from chunks and boulders, ranging from one to three yards wide and possibly wider. In countless numbers they orbit around the big hazy planet, reflecting sunlight like a swary of golden bees.