Your ship falls slowly towards the vast curve of Jupiter. The bulk of the giant planet fills more than half the sky. It glows with dim light, its surface a seething turbulence of stupendous, tossing streamers of methane and ammonia, underlit with weird radiance. Colossal bands of variegated coloration spread from horizon to horizon: umber, rich browns, lighter bands of palest cream, sharp yellow and sanguine gold and orange. Each of these bands are thousands of miles across; some of them are so enormously huge that the entire planet of Caspia could fall into them and be lost without a trace.
In comparison, your ship seems to shrink into insignificance, to become a mote lost in immensity. The boiling, cloud-wrapped surface of the upper atmosphere roars with continent-spanning storms of a violence inconceivable to watchers raised amidst the little storms of tiny Earth. Titanic jets of seething gas are forced from the cloudy surface by cataclysmic pressures: among these gigantic plumes, Caspia itself would be but a fleck of spinning dust.
The chemical imbalance of the Jovian atmosphere generates lightning storms whose ferocity beggared description or comparison. The energy released by a single one of these king-sized thunderbolts could supply light and power to an entire metropolis, enough to last it a good month. And the size of the blazing bolts os on a similarly Brobdingnagian scale: the jagged flare of exploding energy flickers across abysses into which the entire Central Sea could be put a dozen times.
You shudder and shut your eyes to close out the awful vision of Nature in one of her most titanic rages. You know your chances of survival amidst such a convulsion are minuscule. Were you to fall into the upper regions of that seething turbulence, your craft would be shattered to atoms within moments. No man-made structure, regardless of its strength, can resist the stupendous forces that rave and rage below.
The famous Red Spot, that vast ocean of seething crimson vapor, glares up at you like an angry Cyclopian eye. The giant silently roars with its storm-voice; it is hungry, and sees a succulent steely mote escaping.
Ahead of you, filling the heavens, tiny Alcmene looms like a flying cliff, Jove-light gilding its jagged circumference with orange luminance.
Beyond the Asteroid Zone lies the Great Vaporous Giant, largest of all the planets in the Solar System. Besides its many moons, the giant planet with its enormously powerful gravitational field has, over billions of years, gradually pulled into its sphere of influence a number of worldlets fliched from the belt of asteroids that stretches between the Red and the Giant.
The gas giant and its environs are a miniature solar system consisting of one giant planet and dozens of sizable moons, including Ganymede, the largest in the solar system, and Europa, its under-ice oceans.
The Giant is a blurry area of mottled and striped ochre and yellow. Here and there in near space the dull globes of three of the nearer Jovian moons were faintly visible – visible, that is only because their under-portions reflected the ochre radiance from their giant primary.
Before the advent of Caspian, the exploration of Jupiter consisted of only a few automated spacecraft, the first (Pioneer 10) visiting the planet in 1973. The majority of these missions were flybys – detailed observations carried out by the probe without it ever even entering orbit of the gas giant.
During their passage by Jupiter, NASA probes Pioneer 10 and 11 obtained the first close-up images of the planet, as well as charting Jupiter’s intense radiation belts and locating the planet’s magnetic fi eld.
Between 1995 and 2003, the Galileo probe made observations from repeated elliptical orbits around Jupiter, passing low over the Galilean moons. These close approaches resulted in images of unprecedented detail.
When Caspian created settlements on the inner planets, his gaze then turned upon the largest planet and its brood of satellites. By then he now envisioned a future that stretched into infinity, increasingly common to plan for the future in terms of millennia rather than centuries. The Jovian system loomed large in his vision, and even Jupiter isn’t big enough for all of it.