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Saturn's secret should 'boggle' scientists for years

By Robert C. CowenNatural science editor of The Christian Science Monitor / November 14, 1980

Pasadena, Calif.

As Voyager 1 leaves the Saturn system and heads for the depths of outer space , some of the world's greatest planetary scientists already are scurrying around to each other asking, "Amazing, bizarre, what does it all mean?"

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Dramatic pictures of Saturn's rings and tantalizing glimpses of its moons have given scientists a hatful of surprises and puzzles that will keep them busy analyzing and theorizing for years.

Titan was only mildly disappointing in that its thick clouds never did allow a look at its surface. However, data taken at infrared (heat) and radio frequencies are reported to be excellent. They will reveal many details of the structure of Titan, the largest moon in the solar system, and of its atmosphere. Already they have revealed that Titan's atmosphere is composed largely of nitrogen and as least as thick as Earth's atmosphere. Indeed, its surface pressure may be anywhere from one to three times that of Earth. Among other organic chemicals, hydrogen cyanide has been discovered. This is a precusor of the kinds of chemicals involved in organic life, although no one expects life itself to be found on Titan.

A number of Saturn's other moons also have been seen in some detail. Impact craters, extensive and puzzling surface markings, and other features suggest that the moons have had active evolutionary histories. The wealth of information that has been sent back about them should fill in a chapter in solar system development that has been largely blank, Laurence Soderblom of the US Geological Survey said.

Using words such as "bizarre," Dr. Soderblom said that surface features on these moons, which are rich in water ice, will be interesting to explain. Unlike molten rock, which is lighter than solid rock, water is heavier than ice. Thus, features that look volcanic and would be accounted for as outflows of lava on a rocky moon are hard to explain as outflows of water on an icy moon.

Perhaps, he speculated, the water has been charged with gases to the point that it erupts violently when the surface of such a moon is fractured -- a kind of Seltzer-bottle effect. In any event, Soderblom said, the moons of Saturn are a unique system and widen the range of moon types which now are known.

Meanwhile, it is the awesomely beautiful, challengingly complex ring system that has become the hallmark of this Voyager Saturn mission.

It was amazing enough to discover Nov. 11 that two of the ringlets individ ually were eccentric (not circular) and did not quite join smoothly together as they girdled the planet. Dr. Bradford A. Smith of the University of Arizona, leader of the imaging team, explained that no one had expected such rings or even imagined them to exist. He called them "very surprising indeed."

But then on Nov. 12, as Voyager 1 swung within 124,000 kilometers of Saturn's cloudtops, he announced with a mixture of perplexity and amazement that an even more startling phenomenon had appeared. The photos had become detailed enough to show that the narrow "F" ring at the outer fringes of the ring system actually consists of two distinct ringlets. What is more, they appear to cross each other in a loosely braided fashion.