2010 Odyssey Two

THE TRIAL Chapter 5: A CHILD OF THE STARS Chapter 38 Foamscape
The last beast he saw, before he left the oceans of Europa, was much the largest. It closely resembled one of the banyan trees from Earth's tropics, whose scores of trunks allow a single plant to create a small forest sometimes covering hundreds of square metres. The specimen, however, was walking, apparently on a trek between oases. If it was not one of the creatures that had destroyed Tsien, it certainly belonged to a very similar species.

Now he had learned all that he needed to know - or, rather, all that they needed to know. There was one more moon to visit; seconds later, the burning landscape of Io lay below him.

It was as he had expected. Energy and food were there in abundance, but the time was not yet ripe for their union. Around some of the cooler sulphur lakes, the first steps had been taken on the road to life, but before any degree of organization had occurred, all such bravely premature attempts were thrown back into the melting pot. Not until the tidal forces that drove Io's furnaces had lost their power, millions of years later, would there be anything to interest biologists on that seared and sterilized world.

He wasted little time on Io, and none at all on the tiny inner moons that skirted Jupiter's ghostly rings - themselves only pale shadows of the glory that was Saturn's. The greatest of worlds lay before him; he would know it as no man had ever done, or ever would.

The million-kilometre-long tendrils of magnetic force, the sudden explosions of radio waves, the geysers of electrified plasma wider than the planet Earth - they were as real and clearly visible to him as the clouds banding the planet in multihued glory. He could understand the complex pattern of their interactions, and realized that Jupiter was much more wonderful than anyone had ever guessed.

Even as he fell through the roaring heart of the Great Red Spot, with the lightning of its continent-wide thunderstorms detonating around him, he knew why it had persisted for centuries though it was made of gases far less substantial than those that formed the hurricanes of Earth. The thin scream of hydrogen wind faded as he sank into the calmer depths, and a sleet of waxen snowflakes - some already coalescing into barely palpable mountains of hydrocarbon foam - descended from the heights above. It was already warm enough for liquid water to exist, but there were no oceans there; that purely gaseous environment was too tenuous to support them.

He descended through layer after layer of cloud, until he entered a region of such clarity that even human vision could have scanned an area more than a thousand kilometres across. It was only a minor eddy in the vaster gyre of the Great Red Spot; and it held a secret that men had long guessed, but never proved.

Skirting the foothills of the drifting foam mountains were myriads of small, sharply-defined clouds, all about the same size and patterned with similar red and brown mottlings. They were small only as compared with the inhuman scale of their surroundings; the very least would have covered a fair-sized city.

They were clearly alive, for they were moving with slow deliberation along the flanks of the aerial mountains, browsing off their slopes like colossal sheep. And they were calling to each other in the metre band, their radio voices faint but clear against the cracklings and concussions of Jupiter itself.

Nothing less than living gasbags, they floated in the narrow zone between freezing heights and scorching depths. Narrow, yes - but a domain far larger than all the biosphere of Earth.

They were not alone. Moving swiftly among them were other creatures so small that they could easily have been overlooked. Some of them bore an almost uncanny resemblance to terrestrial aircraft and were of about the same size. But they too were alive - perhaps predators, perhaps parasites, perhaps even herdsmen.

A whole new chapter of evolution, as alien as that which he had glimpsed on Europa, was opening before him. There were jet-propelled torpedoes like the squids of the terrestrial oceans, hunting and devouring the huge gasbags. But the balloons were not defenceless; some of them fought backs with electric thunderbolts and with clawed tentacles like kilometre-long chainsaws.

There were even stranger shapes, exploiting almost every possibility of geometry - bizarre, translucent kites, tetrahedra, spheres, polyhedra, tangles of twisted ribbons.

The gigantic plankton of the Jovian atmosphere, they were designed to float like gossamer in the uprising currents, until they had lived long enough to reproduce; then they would be swept down into the depths to be carbonized and recycled in a new generation.

He was searching a world more than a hundred times the area of Earth, and though he saw many wonders, nothing there hinted of intelligence. The radio voices of the great balloons carried only simple messages of warning or of fear. Even the hunters, who might have been expected to develop higher degrees of organization, were like the sharks in Earth's oceans - mindless automata.

And for all its breathtaking size and novelty, the biosphere of Jupiter was a fragile world, a place of mists and foam, of delicate silken threads and paper-thin tissues spun from the continual snowfall of petrochemicals formed by lightning in the upper atmosphere. Few of its constructs were more substantial than soap bubbles; its most terrifying predators could be torn to shreds by even the feeblest of terrestrial carnivores.

Like Europa on a vastly grander scale, Jupiter was an evolutionary cul-de-sac. Consciousness would never emerge here; even if it did, it would be doomed to a stunted existence. A purely aerial culture might develop, but in an environment where fire was impossible, and solids scarcely existed, it could never even reach the Stone Age.

And now, as he hovered above the centre of a Jovian cyclone merely as large as Africa, he became aware once again of the presence controlling him. Moods and emotions were leaking into his own consciousness, though he could not identify any specific concepts or ideas. It was as if he were listening, outside a closed door, to a debate in progress, and in a language he could not understand. But the muffled sounds clearly conveyed disappointment, then uncertainty, then a sudden determination - though for what purpose he could not tell. Once again, he felt like a pet dog, able to share his master's changing moods but not to comprehend them.

And then the invisible leash was taking him down toward the heart of Jupiter. He was sinking through the clouds, below the level where any form of life was possible.

Soon he was beyond the reach of the last rays from the faint and distant Sun. The pressure and temperature were swiftly mounting; already it was above the boiling point of water, and he passed briefly through a layer of superheated steam. Jupiter was like an onion; he was peeling it away skin by skin, though as yet he had travelled only a fraction of the distance to its core.

Beneath the steam was a witches' brew of petrochemicals - enough to power for a million years all the internal-combustion engines that mankind had dyer built. It became thicker and denser; then, quite abruptly, it ended at a discontinuity only a few kilometres thick.

Heavier than any rocks on Earth, yet still a liquid, the next shell consisted of silicon and carbon compounds of a complexity that could have provided lifetimes of work for terrestrial chemists. Layer followed layer for thousands of kilometres, but as the temperature rose into the hundreds and then the thousands of degrees, the composition of the various strata became simpler and simpler. Halfway down to the core, it was too hot for chemistry; all compounds were torn apart, and only the basic elements could exist.

Next there came a deep sea of hydrogen - but not hydrogen as it had ever existed for more than a fraction of a second in any laboratory on Earth. This hydrogen was under such enormous pressure that it had become a metal.

He had almost reached the centre of the planet, but Jupiter had one more surprise in store. The thick shell of metallic yet still fluid hydrogen ended abruptly. At last, there was a solid surface, sixty thousand kilometres down.

For ages, the carbon baked out of the chemical reactions far above had been drifting down toward the centre of the planet. There it had gathered, crystallizing at a pressure of millions of atmospheres. And there, by one of Nature's supreme jests, was something very precious to mankind.

The core of Jupiter, forever beyond human reach, was a diamond as big as the Earth.