As they ascended in space and time the shining fields were restored. The children dwindled to invisibility and the farmland shrank to a patchwork of detail, obscured by mist and cloud.
And then, as Earth receded, the bulbous shape of Africa itself, schoolbook-familiar, swam into Bobby's view.
Farther to the west, over the Atlantic, a solid layer of clouds lay across the ocean's curving skin, corrugated in neat gray-white rows. As the turning planet bore Africa toward the shadow of night, Bobby could see equatorial thunderheads spreading hundreds of kilometers toward the land, probing purple fingers of darkness.
But even from this vantage Bobby could make out the handiwork of man.
There was a depression far out in the ocean, a great cappuccino swirl of white clouds over blue ocean. But this was no natural system; it had a regularity and stability that belied its scale. The new weather management functions were, slowly, reducing the severity of the storm systems that still raged across the planet, especially around the battered Pacific Rim.
To the south of the old continent Bobby could clearly see the great curtain-ships working their way through the atmosphere, the conducting sheets they bore shimmering like dragonfly wings as they cleansed the air and restored its long-depleted ozone. And off the western coast pale masses followed the line of the shore for hundreds of kilometers: reefs built up rapidly by the new breed of engineered coral, laboring to fix excess carbon—and to provide a new sanctuary for the endangered communities of plants and animals which had once inhabited the world's natural reefs, long destroyed by pollution, over-fishing and storms.
Everywhere, people were working, repairing, building.
The land, too, had changed. The continent was almost cloud free, its broad land gray-brown, the green of life suppressed by mist. The great northern mass which had been the Sahara was broken by a fine tracery of blue white. Already, along the banks of the new canals, the glow of green was starting to spread. Here and there he could see the glittering jewel-like forms of PowerPipe plants, the realization of Hiram's last dream, drawing heat from the core of Earth itself—the energy bounty, free and clean, which had largely enabled the planet's stabilizing and transformation. It was a remarkable view, its scale and regularity stunning; David said it reminded him of nothing so much as the old dreams of Mars, the dying desert world restored by intelligence.
The human race, it seemed, had gotten smart just in time to save itself. But it had been a difficult adolescence.
Even as the human population had continued to swell, climatic changes had devastated much of the world's food and water supply, with the desertification of the great grain regions of the U.S. and Asia, the drowning of many productive lowland farming areas by rising sea levels, and the pollution of aquifers and the acidification or drying of freshwater lakes. Soon the problem of excess population went into reverse as drought, disease and starvation culled communities across the planet. It was a crash only in relative terms; most of Earth's population had survived. But as usual the most vulnerable—the very old and the very young—had paid the price.
Overnight, the world had become middle-aged.
New generations had emerged into a world that was, recovering, still crowded with aging survivors. And the young—scattered, cherished, WormCam-linked—regarded their elders with increasing intolerance, indifference and mistrust.
In the schools, the children of the WormCam made academic studies of the era in which their parents and grandparents had grown up: an incomprehensible, taboo-ridden pre-WormCam age only a few decades in the past in which liars and cheats had prospered, and crime was out of control, and people killed each other over lies and myths, and in which the world had been systematically trashed through willful carelessness, greed, and an utter lack of sympathy for others or foresight regarding the future.
And meanwhile, to the old, the young were a bunch of incomprehensible savages with a private language and about as much modesty as a tribe of chimpanzees...
But the generational conflict was not the full story. It seemed to Bobby that a more significant rift was opening up.
The mass minds were still, Bobby supposed, in their infancy, and they were far outnumbered by the Unjoined older generations—but already their insights, folded down into the human world, were having a dramatic effect.
The new superminds were beginning to rise to the greatest of challenges: challenges which demanded at once the best of human intellect and the suppression of humanity's worst divisiveness and selfishness. The modification and control of the world's climate, for example, was, because of the intrinsically chaotic nature of the global weather systems, a problem that had once seemed intractable. But it was a problem that was now being solved.
The new generations of maturing Joined were already shaping the future. It would be a future in which, many feared, democracy would seem irrelevant, and in which even the consolation of religion would not seem important; for the Joined believed—with some justification—that they could even banish death.
Perhaps it would not even be a human future at all.
It was wonderful, awe-inspiring, terrifying. Bobby knew that he was privileged to be alive at such a moment, for surely such a great explosion of mind would not come again.
But it was also true that he—and David and the rest of their generation, the last of the Unjoined—had come to feel more and more isolated on the planet that had borne them.
He knew this shining future was not for him. And—a year after Kate's death, the illness that had suddenly taken her from him—the present held no interest. What remained for him, as for David, was the past.
And the past was what he and David had decided to explore, as far and as fast as they could, two old fools who didn't matter to anybody else anyhow.
He felt a pressure—diffuse, almost intangible, yet summoning. It was as if his hand were being squeezed. "David?"
"Are you ready?"
Bobby let a corner of his mind linger in his remote body, just for a second; shadowy limbs formed around him, and be took a deep breath, squeezed his hands into fists, relaxed again. "Let's do it."
Now Bobby's viewpoint began to fall from the African sky, down toward the southern coast. And as he fell, day and night began to flap across the patient face of the continent, centuries falling away like leaves from an autumn tree.
A hundred thousand years deep, they paused. Bobby and David hovered like two fireflies before a face: heavy-browed, flat-nosed, clear-eyed, female.
Not quite human.
Behind her, a small family group—powerfully built adults, children like baby gorillas—were working at a fire they had built on his ancient beach. Beyond them was a low cliff, and the sky above was a crisp, deep blue; perhaps this was a winter's day.
The brothers sank deeper.
The details, the family group, the powder-blue sky, winked out of existence. The Neanderthal grandmother herself blurred, becoming expressionless, as one generation was laid over another, too fast for the eye to follow. The landscape became a grayish outline, centuries of weather and seasonal growth passing with each second.
The multiple-ancestor face flowed and changed. Half a million years deep her forehead lowered, her eye socket ridges growing more prominent, her chin receding, her teeth and jaws pronounced. Perhaps this face was now apelike, Bobby thought. But those eyes remained curious, intelligent.
Now her skin tone changed in great slow washes, dark to light to dark.
"Homo Erectus." David said. "A toolmaker. Migrated around the planet. We're still falling. A hundred thousand years every few seconds, good God. But so little changes!..."
The next transition came suddenly. The brow sank lower, the face grew longer—though the brain of this remote grandmother, much smaller than a modern human's, was nevertheless larger than a chimpanzee's.
"Homo Habilis," said David. "Or perhaps this is Australopithecus. The evolutionary lines are tangled. We're already two million years deep."
The
anthropological labels scarcely mattered. It was profoundly disturbing, Bobby found, to gaze at this flickering multi-generation face, the face of a chimpanzee-like creature he might not have looked at twice in some zoo... and to know that this was his ancestor, the mother of his grandmothers, in an unbroken line of descent. Maybe this was how the Victorians felt when Darwin got back from the Galapagos, he thought.
Now the last vestiges of humanity were being shed, the brain pan shrinking further, those eyes growing cloudy, puzzled.
The background, blurred by the passage of the years, became greener. Perhaps there were forests covering Africa, this deep in time. And still the ancestor diminished, her face, fixed in the glare of the WormCam viewpoint, becoming more elemental, those eyes larger, more timid. Now she reminded Bobby more of a tarsier, or a lemur.
But yet those forward-facing eyes, set in a flat face, still held a poignant memory, or promise.
David impulsively slowed their descent, and brought them fleetingly to a halt some forty million years deep.
The shrewlike face of the ancestor peered out at Bobby, eyes wide and nervous. Behind her was a background of leaves, branches. On a plain beyond, dimly glimpsed through green light, there was a herd of what looked like rhinoceros—but with huge, misshapen heads, each fitted with six horns. The herd moved slowly, massive, tails flicking, browsing on low bushes, and reaching up to the dangling branches of trees. Herbivores, then. A young straggler was being stalked by a group of what looked like horses—but these "horses," with prominent teeth and tense, watchful motions, appeared to be predators.
David said, "The first great heyday of the mammals. Forests all over the planet; the grasslands have all but disappeared. And so have the modern fauna: there are no fully-evolved horses, rhinos, pigs, cattle, cats, dogs..."
The grandmother's head flicked from side to side, nervously, every few seconds, even as she chewed on fruit and leaves. Bobby wondered what predators might loom out of this strange sky to target an unwary primate.
With Bobby's unspoken consent, David released the moment, and they fell away once more. The background blurred into a blue-green wash, and the ancestor's face flowed, growing smaller, her eyes wider and habitually black. Perhaps she had become nocturnal.
Bobby glimpsed vegetation, thick and green, much of it unfamiliar. And yet now the land seemed strangely empty: no giant herbivores, no pursuing carnivores crossed the empty stage beyond his ancestor's thin-cheeked, shadowed, huge-eyed face. The world was like a city deserted by humans, he thought, with the tiny creatures, the rats and mice and voles burrowing among the huge ruins.
But now the forests began to shrink back, melting away like summer mist. Soon the land became skeletal, a plain marked by broken stumps of trees that must once have risen tall.
Ice gathered suddenly, to lie in thick swaths across the land. Bobby sensed life drawing out of this world like a slow tide.
And then clouds came, immersing the world in darkness. Rain, dimly glimpsed, began to leap from the darkened ground. Great heaps of bones assembled from the mud, and flesh gathered over them in gray lumps.
"Acid rain," murmured David.
Light flared, dazzling, overwhelming.
It was not the light of day, but of a fire that seemed to span the landscape. The fire's violence was huge, startling, terrifying.
But it drew back.
Under a leaden sky, the fires began to collapse into isolated blazes that dwindled further, each licking flame restoring the greenery of another leafy branch. The fire drew at last into tight, glowing pellets that leapt into the sky, and the fleeing sparks merged into a cloud of shooting stars under a black sky.
Now the thick black clouds drew back like a curtain. A great wind passed, restoring smashed branches to the trees, gently ushering flocks of flying creatures to the branches. And on the horizon a fan of light was gathering, growing pink and white, at last turning into a beacon beam of brilliance pointing directly up into the sky.
It was a column of molten rock.
The column collapsed into an orange glow. And, like a second dawn, a glowing, diffuse mass rose above the horizon, a long, glowing tail spreading across half the sky in a great flamboyant curve. Masked by the daylight, brilliant in the night, the comet receded, day by day, drawing its cargo of destruction back into the depths of the Solar System.
The brothers paused in a suddenly restored world, a world of richness and peace.
The ancestor was a wide-eyed, frightened creature that lingered above ground, perhaps incautiously trapped there.
Beyond her, Bobby glimpsed what appeared to be the shore of an inland sea. Lush jungles lapped the swampy lowlands along the coast, and a broad river decanted from distant blue mountains. The broad ridged backs of what must be crocodiles sliced through the river's sluggish, muddy waters. This was a land thick with life—unfamiliar in detail, and yet not so unlike the forests of his own youth.
But the sky was not a true blue-more a subtle violet, he thought; even the shapes of the clouds, scattered overhead, seemed wrong. Perhaps the very air was different here, so deep in time.
A herd of horned creatures moved along the swampy coast, looking something like rhinos. But their movements were strange, almost birdlike, as, lumbering, they mingled, browsed, nested, fought, preened. And there was a herd of what looked at first glance like ostriches—walking upright, with bobbing heads, nervous movements and startled, suspicious glances.
In the trees Bobby glimpsed a huge shadow, moving slowly, as if tracking the giant plant-eaters. Perhaps this was a carnivore—even, he thought with a thrill, a raptor.
All around the dinosaur herds, clouds of insects hovered.
"We're privileged," David said. "We've a relatively good view of the wildlife. The dinosaur age has been a disappointment for the time tourists. Like Africa, it turns out to be huge and baffling and dusty and mostly empty. It stretches, after all, over hundreds of millions of years."
"But," Bobby said dryly, "it was kind of disappointing to discover that T. rex was after all just a scavenger... All this beauty, David, and no mind to appreciate it. Was it waiting for us all this time?"
"Ah, yes, the unseen beauty. 'Were the beautiful volute and cone shells of the Eocene epoch and the gracefully sculpted ammonites of the Secondary period created that man might ages afterward admire them in his cabinet?' Darwin, in the Origin of Species."
"So he didn't know either."
"I suppose not. This is an ancient place, Bobby. You can see it: an antique community that has evolved together, across hundreds of millions of years. And yet..."
"And yet it would all disappear, when the Cretaceous Wormwood did its damage."
"The Earth is nothing but a vast graveyard, Bobby. And, as we dive deeper into the past, those bones are rising again to confront us...."
"Not quite. We have the birds."
"The birds, yes. Rather a beautiful end to this particular evolutionary subplot, don't you think? Let's hope we turn out so well. Let's go on."
"Yes."
So they plunged once more, dropping safely through the dinosaurs' Mesozoic summer, two hundred million years deep.
Ancient jungles swept in a meaningless green wash across Bobby's view, framing the timid, mindless eyes of millions of generations of ancestors, breeding, hoping, dying.
The greenery abruptly cleared, revealing a flat dusty plain, an empty sky.
The denuded land was a desert, baked hard and flat beneath a high, harsh sun, the sands uniformly reddish in color. Even the hills had shifted and flowed, so deep was time.
The ancestor here was a small reptile-like creature who nibbled busily on what looked like the remains of a baby rat. She was on the fringe of a scrubby forest, of stunted ferns and conifers, that bordered a straggling river.
Something like an iguana scampered nearby, flashing rows of sharp teeth. Perhaps that was the mother of all the dinosaurs, Bobby mused. And, beyond the trees, Bobby made out what looked like warthogs, grubb
ing in the mud close to the sluggish water.
David grunted. "Lystrosaurs." he said. "Luckiest creatures who ever lived. The only large animal to survive the extinction event."
Bobby was confused. "You mean the dinosaur-killer comet?"
"No," David said grimly. "I mean another, the one we must soon pass through, two hundred and fifty million years deep. The worst of them all..."
So that was why the great lush jungle panorama of the dinosaurs had drawn back. Once again, the Earth was emptying itself of life. Bobby felt a profound sense of dread.
They descended once more.
At last the final, stunted trees shuddered back into their buried seeds, and the last greenery—struggling weeds and shrubs—shriveled and died. A scorched land began to reconstitute itself, a place of burned-out stumps and fallen branches and, here and there, heaped-up bones. The rocks, increasingly exposed by the receding tide of life, became powerfully red.
"It's like Mars."
"And for the same reason," David said grimly. "Mars has no life to speak of; and, in life's absence, its sediments have rusted: slowly burning, subject to erosion and wind, killing heat and cold. And so Earth, as we approach this greatest of the deaths, was the same: all but lifeless, the rocks eroding away."
And all through this, a chain of tiny ancestors clung to life, subsisting in muddy hollows at the fringes of inland seas that had almost—but not quite—dried to bowls of lethal Martian dust.
Earth in this era was very different, David said. Tectonic drift had brought all of the continents into a single giant assemblage, the largest landmass in the history of the planet. The tropical areas were dominated by immense deserts, white the high latitudes were scoured by glaciation. In the continental interior the climate swung wildly between killing heat and dry freezing.
And this already fragile world was hit by a further calamity; a great excess of carbon dioxide, which choked animals and added greenhouse heating to an already near-lethal climate.
"Animal life in particular suffered: almost knocked back to the level of pond life. But for us it's nearly over, Bobby; the excess CO, is drawing back into where it came from: deep sea traps and a great outpouring of flood basalts in Siberia, gases brought up from Earth's interior to poison its surface. And soon that monstrous world continent will break up.