Eberly thought a moment, eyes cast downward, then looked squarely at Wilmot and said, “Yes, I can agree to that.”

“Good,” said Wilmot, getting to his feet and extending his hand across the desk. “We are agreed, then.”

Eberly and Holly stood up and shook Wilmot’s hand in turn. As they left his office, Wilmot sank back into his chair, thinking that he should write up this encounter and have it ready to send back to Atlanta as quickly as possible.

It is the most beautiful sight in the solar system: Saturn and its glowing, glorious rings.

They arch above the planet’s equator like a bridge of light, circling the ponderous flattened sphere of the planet, hovering above its middle as if in splendid defiance of gravity.

The second-largest planet of our solar system, Saturn is slightly smaller than Jupiter, but orbits twice as far from the Sun. Like Jupiter, Saturn is a gas giant world, composed almost entirely of the lightest elements, hydrogen and helium. If you could build a swimming pool nearly ten times the size of Earth, Saturn would float in it: the planet’s density is slightly less than water’s.

Approaching Saturn, the planet’s pale yellow and tan clouds churn across a disc that is noticeably flattened by its frenetic spin rate. Saturn’s day is a scant ten hours and thirty-nine minutes. Yet to the ancients, Saturn was the farthest planet they could see, and the slowest in making its way around the sky. At ten times the Earth’s distance from the Sun, it takes 29.46 Earth years for Saturn to circle the Sun once.

The ring system is what makes Saturn so beautiful, so intriguing. Jupiter and the farther worlds of Uranus and Neptune have narrow, faint rings circling them. Saturn has broad bands of rings, shining brilliantly, suspended about the planet’s middle, hanging in emptiness like a magnificent set of halos.

When Galileo first turned his primitive telescope to Saturn he thought he saw a triple planet: His small lenses could not make out the rings, to him they looked like strange ears sprouting on either side of the planet. He wrote to the German astronomer Johannes Kepler a letter in code, so that it could be read only by its intended recipient.

“I have observed the highest planet to be triple-bodied,” Galileo wrote in an anagram. Kepler misunderstood, and thought that Galileo meant he had discovered two moons of Mars.

As telescopes improved, astronomers discovered those impossible rings. To this day, Saturn is one of the first objects that amateur astronomers turn to. The sight of the ringed planet never fails to inspire admiring, delighted sighs.

Saturn’s beautiful rings are composed of particles of ice and ice-covered dust. While most of the particles are no larger than dust motes, some are as big as houses. The rings are about four hundred thousand kilometers across, yet not much thicker than a hundred meters. They have been described as “proportionally as thick as a sheet of tissue paper spread over a football field.”

The rings’ total mass amounts to that of an icy satellite no more than one hundred kilometers in diameter. They are either the remains of one or more moons that got too close to the planet and were broken up by gravitational tidal forces, or leftover material from the time of the planet’s formation which never coalesced into a single body because it was too close to Saturn to do so.

The rings are dynamic. Hundreds of millions of particles circling the mammoth planet, constantly colliding, bouncing off one another, breaking into smaller fragments, banging and jouncing like an insane speedway full of lunatic drivers.

The dynamics of the rings are fascinating. There are gaps between the major rings, spaces of emptiness caused by the gravitational pulls of Saturn’s several dozen moons. The rings are accompanied by tiny “sheepdog” satellites, minuscule moons that circle just outside or just inside each ring and apparently keep them in place with their tiny gravitational influence. The rings are self-sustaining: As particles are sucked down into the planet, new particles are chipped off the shepherd moons by constant collisions with the hurtling, jostling particles, abraded off these tiny moonlets as they grind their way around the planet, constantly bombarded by the blizzard of tiny icy particles through which they orbit.

The main rings are actually composed of hundreds of thinner ringlets that appear to be braided together. Spacecraft time-lapse photos also show mysterious spokes weaving through the largest of the rings, patterns of light and dark that remain unexplained and fascinating. Perhaps Saturn’s extensive magnetosphere electrically charges the dust particles in the ring and levitates them, which may give rise to the spokes.

The planet itself presented an enigma to the inquisitive scientists from Earth. Like the more massive Jupiter, Saturn is heated from within, its core of molten rock seething from the pressure of the giant world squeezing down upon it. But Saturn is smaller than Jupiter, farther from the Sun, and therefore colder. Where Jupiter harbors a flourishing biosphere of aerial organisms in its thick hydrogen atmosphere, and an even more complex ecology of seagoing creatures in its deep planetwide ocean, Saturn seems bereft of life, except for the cold-adapted microbes that dwell in its upper cloud deck.

“Saturn is a dead end, as far as multicellular life is concerned,” pronounced a disappointed astrobiologist after the earliest probes scanned the vast ocean that swirls beneath the ringed world’s perpetual clouds, “just over the edge of habitability for anything more complex than single-celled organisms.”

Wistfully, he added, “Just a little warmer and we would have had a duplicate of Jupiter.”

Among the billions of ice particles that make up the rings, some prebiological chemical activity has been detected by robotic probes, but no evidence for living organisms has been found, as yet.

Saturn’s giant moon, Titan, is an altogether different matter, however. A rich ecology of hydrocarbon-based microbes exists there, placing Titan off-limits for any development or industrial exploitation. No one but scientists are allowed at Titan, and even they have refrained from sending to its surface anything except completely sterilized robot probes.

The scientific community and the International Astronautical Authority are agreed that humans must not endanger Titan’s ecology with the threat of contamination.

But others do not agree.