Manifold: Space

by Stephen Baxter

  "You don't understand," Ben said tightly. "I think that was a procoptodon: a giant kangaroo. They grow as high as three meters..."

  Madeleine knew nothing about kangaroos. "And that's unusual?"

  "Madeleine, procoptodon has been extinct for ten thousand years. That's what makes it unusual."

  They walked on, farther from the car, sipping water from flasks.

  "It's the Gaijin," he said. "Of course it's the Gaijin. They are restoring megafauna that have long been extinct here. There have been sightings of wanabe, a snake a meter in diameter and seven long, a flightless bird twice the mass of an emu called genyornis... The Gaijin seem to be tinkering with the genetic structure of existing species, exploring these archaic, lost forms."

  They came upon an area of bare rock that was littered with bones. The bones were broken up and scattered, and had apparently been gnawed. Few of the fragments were large enough for her to recognize – was this an eye socket, that a piece of jaw?

  "We think they use parsimony analysis," Ben was saying. "DNA erodes with time. But you can deconstruct evolution if you have access to the evolutionary products. You track backward to find the common gene from which all the products descended; the principle is to seek the smallest number of branch points from which the present family could have evolved. When you have the structure you can recreate the ancient gene by splicing synthesized sequences into modern genes. You see?" He stopped, panting lightly. "And, Madeleine, here's a thought. Australia has been an island, save for intervals of bridging during the Ice Ages, for a hundred million years. The genetic divergence between modern humans is widest between Australian natives and the rest of the population."

  "So if you wanted to think about picking apart the human genome –"

  "– here would be a good place to start."

  She thought of the Gaijin she had seen undoing itself, decades back, in Kefallinia. "Perhaps they are dismantling us. Taking apart the biosphere, to see how it works."

  "Perhaps. You know, humans always believed that when the aliens arrived, they would bring wisdom from the stars. Instead they seem to have arrived with nothing but questions. Now, they have grown dissatisfied with our answers, and are seeking their own... Of course, it might help if they told us what it is they are looking for. But we are starting to guess."

  "We are?"

  They walked on, slowly, conserving their energy.

  He eyed her. "For somebody who has traveled so far, you sometimes seem to understand little. Let me tell you another theory. Can you see any cactus, here in our desert?"

  No, as it happened. In fact, now she thought about it, there were none of the desert plants she was accustomed to from the States.

  Ben told her now that this was because of Australia's long history. Once it had been part of a giant super-Africa continent called Gondwanaland. When Australia had split off and sailed away, it had carried a freight of rain-forest plants and animals that had responded to the growing aridity by evolving into the forms she saw here.

  He rubbed his fingers in the red dirt. "The continents are rafts of granite that ride on currents of magma in the mantle. We think the continents merge and break up, moving this way and that, under the influence of changes in those currents."

  "All right."

  "But we don't know what causes those magma currents to change. We used to think it must be some dynamic internal to the Earth."

  "But now –"

  "Now we aren't so sure." He smiled thinly. "Imagine a huge war. A bombardment from space. Imagine a major strike, an asteroid or comet, hitting the ocean. It would punch through the water like a puddle, not even noticing it was there, and then crack the ocean floor." His lips pursed. "Think of a scum on water. Now throw in a few rocks. Imagine the islands of dirt shattering, convulsing, whirling around and uniting again. That was what it was like. If it happened, it shaped the whole destiny of life on Earth. The impact structures wouldn't be easy to spot, because the ocean floor gets dragged under the continents and melted. After two hundred million years, the ocean floor is wiped clean. Nevertheless there are techniques..."

  A huge war. Rocks hurled from the sky, battering the Earth. Tens of millions of years ago. The hot dusty land seemed to swivel around her.

  It sounded like an insane conspiracy theory. To attribute the evolution of Venus to the activities of aliens was one thing. But this... Could it possibly be true that everything she had seen today – the animals, the ancient land – was all shaped by intelligence, by careless war?

  "Is this why you brought me to Australia? To tell me this?"

  He grinned. "On Earth, as it is in Heaven, Madeleine. We seem to find it easy to discuss the remaking of remote rocky worlds by waves of invaders – even Venus, our twin. But why should Earth have been spared?"

  "And this is why you follow Nemoto?"

  "If the Gaijin understand this – that we live in a universe of such dreadful violence – don't you think they should, at the very least, tell us?..." Ben found what looked like a piece of thigh bone. "I'm not an expert," he said. "But I think this was a diprotodon. A wombatlike creature the size of a rhino."

  "Another Gaijin experiment."

  "Yes." He seemed angry again, in his controlled, internalized way. "Who knows how it died? From hunger, perhaps, or thirst, or just simple sunburn. These are archaic forms; this isn't the ecology they evolved in."

  "And so they die."

  "And so they die."

  They walked on, and found more bones of animals that should have been dead for ten thousand years – huge, failed experiments, bleached in the unrelenting Sun.

  The Saddle Point gateway was a simple hoop of some powder-blue material, facing the Sun, perhaps thirty meters across. Madeleine thought it was classically beautiful. Elegant, perfect.

  As the flower-ship approached, Madeleine's fear grew. Ben told her Dreamtime stories, and she clung to him. "Tell me..."

  There was no deceleration. At the last minute the flower-ship folded up its electromagnetic petals, and the silvery ropes coiled back against the ship's flanks, turning it into a spear that lanced through the disc of darkness.

  Blue light bathed Madeleine's face. The light increased in intensity until it blinded them.

  With every transition, there is a single instant of pain, unbearable, agonizing.

  ...But this time, for Madeleine, the pain didn't go away.

  Ben held her as the cool light of different Suns broke over the flower-ship, as she wept.

  Chapter 16

  Icosahedral God

  The Saddle Point for the Chaera's home system turned out to be within the accretion disc of the black hole itself. Ben and Madeleine clung to the windows as smoky light washed over the scuffed metal and plastic surfaces of the habitat.

  The accretion disc swirled below the flower-ship, like scum on the surface of a huge milk churn. The black hole was massive for its type, Madeleine learned – meters across. Matter from the accretion disc tumbled into the hole continually; X rays sizzled into space.

  The flower-ship passed through the accretion disc. The view was astonishing.

  The disc foreshortened. They fell into shadows a million kilometers long.

  A crimson band swept upward past the flower-ship. Madeleine caught a glimpse of detail, a sea of gritty rubble. The disc collapsed to a grainy streak across the stars; pea-sized pellets spanged off Ancestor's hull plates. Then the ship soared below the plane of the disc.

  A brilliant star gleamed beneath the ceiling of rubble. This was a stable G2 star, like the Sun, some five astronomical units away – about as far as Jupiter was from Sol. The black hole was orbiting that star, a wizened, spitting planet.

  Soon, the monitors mounted on the Ancestor's science platform started to collect data on hydrogen alpha emission, ultraviolet line spectra, ultraviolet and X-ray imaging, spectrography of the active regions. Ben took charge now, and training and practice took over as the two of them went into the routine tasks of studying the hole
and its disc.

  Nemoto had hooked up to the Chaera's tank a powerful bioprocessor, a little cubical unit that would enable the humans to communicate, to some extent, with the Chaera and with their Gaijin hosts. When they booted it up, a small screen displayed the biopro's human-interface design metaphor. It was a blocky, badly synched, two-dimensional virtual representation of Nemoto's leathery face.

  "The vanity of megalomaniacs," Madeleine murmured. "It's a pattern."

  Ben didn't understand. The Nemoto virtual grinned.

  Ben and Madeleine hovered before a window into the Chaera's tank.

  If Madeleine had encountered this creature in some deep-sea aquarium – and given she was no biologist – she mightn't have thought it outlandishly strange. After all it had those remarkable eyes.

  The eyes were, of course, a stunning example of convergent evolution. On Earth, eyes conveyed such a powerful evolutionary advantage that they had been developed independently perhaps forty times – while wings seemed to have been invented only three or four times, and the wheel not at all. Although details differed – the eyes of fish, insects, and people were very different – nevertheless all eyes showed a commonality of design, for they were evolved for the same purpose, and were constrained by physical law.

  You might have expected ETs to show up with eyes.

  The Chaera communicated by movement, their rippling surfaces sending low-frequency acoustic signals through the fluid in which they swam. In the tank, lasers scanned the Chaera's surface constantly, picking up the movements and affording translations.

  Interspecies translation was actually getting easier, after the first experience with the Gaijin. A kind of meta-language had been evolved, an interface that served as a translation buffer between ET "languages" and every human tongue. The meta-language was founded on concepts – space, time, number – that had to be common to any sentient species embedded in three-dimensional space and subject to physical law, and it had verbal, mathematical, and diagrammatic components; to Madeleine's lay understanding it seemed to be a fusion of Latin and Lincos.

  Madeleine felt an odd kinship with the spinning, curious creature, a creature that might have come from Earth, much more sympathetic than any Gaijin. And if we have found you so quickly, perhaps we will find less strangeness out there than we expect.

  "What is it saying?" Ben asked.

  Virtual Nemoto translated. "The Chaera saw the disc unfolding. 'What a spectacle. I am the envy of generations...' "

  Mini black holes, Madeleine learned, were typically the mass of Jupiter. Too small to have been formed by processes of stellar collapse, they were created a millionth of a second after the Big Bang, baked in the fireball at the birth of the universe.

  Mini black holes, then, seemed to be well understood. The oddity here was to find such a hole in a neat circular orbit around this Sun-like star.

  "And the real surprise," virtual Nemoto said, "was the discovery, by the Gaijin, of life, infesting the accretion disc of a mini black hole. The Chaera. It seems that this black hole is God for the Chaera."

  "They worship a black hole?" Madeleine asked.

  "Evidently," Nemoto said impatiently. "If the translation programs are working. If it's possible to correlate concepts like 'God' and 'worship' across species barriers."

  Ben murmured wordlessly. Madeleine looked over his shoulder.

  In the central glare of the accretion disc, there was something surrounding the black hole, embedding it.

  The black hole was set into a netlike structure that started just outside the Schwarzschild radius and extended kilometers. The structure was a regular solid of twenty triangular faces.

  "It's an icosahedron," Ben said. "My God, it is so obviously artificial. The largest possible Platonic solid. Triumphantly three-dimensional."

  Madeleine couldn't make out any framework within the icosahedron, or any reinforcement for its edges; it was a structure of sheets of almost transparent film, each triangle hundreds of meters wide. The glow of the flower-ship's hungry ramscoop shone and sparkled from the multiple facets.

  "It must be mighty strong to maintain its structure against the hole's gravity, the tides," Ben said. "It seems to be directing the flow of matter from the accretion disc into the event horizon..."

  It was a jewel-box setting for a black hole. A comparative veteran of interstellar exploration, Madeleine felt stunned.

  The Chaera thrashed in its tank.

  "Time to pay the fare," Nemoto said. "Are we ready to speak to God?"

  Madeleine turned to Ben. "We didn't know about this. Maybe we should think about what we're doing here."

  He shrugged. "Nemoto is right. It is not our mission." He began the operations they'd rehearsed.

  Reluctantly, Madeleine worked a console to unship the first of the old X-ray lasers; the monitors showed it unfolding from its mount like a shabby flower.

  The self-directed laser dove into the heart of the system, heading for its closest approach to the hole.

  "Three, two, one," Ben murmured.

  There was a flash of light, pure white, that shone through the Service Module's ports.

  Various instruments showed surges of particles and electromagnetic radiation. The laser's fission-bomb power source had worked. The shielding of Ancestor seemed adequate.

  The X-ray beam washed over the surface of "God." The net structure stirred, like a sleeping snake.

  The Chaera quivered.

  Ben was watching the false-color images. "Madeleine. Look."

  The surface of "God" was alive with motion; the icosahedral netting was bunching itself around a single, brooding point, like skin crinkling around an eye.

  "I can give you a rough translation from the Chaera," Nemoto said. " 'She heard us.' "

  Madeleine asked, " 'She'?"

  "God, of course. 'If I have succeeded... then I will be the most honored of my race. Fame, wealth, my choice of mates –' "

  Madeleine laughed sourly. "And, of course, religious fulfillment."

  Ben monitored a surge of X-ray photons and high-energy particles coming from the hole – and the core at the center of the crinkled net exploded. A pillar of radiation punched through the accretion disc like a fist.

  The Chaera wobbled around its tank.

  " 'God is shouting,' " Nemoto said. She peered out of her biopro monitor tank, her wizened virtual face creased with doubt.

  The beam blinked out, leaving a trail of churning junk.

  The flower-ship entered a long, powered orbit that would take it, for a time, away from the black hole and in toward the primary star and its inner system. Madeleine and Ben watched the black hole and its enigmatic artifact recede to a toylike glimmer.

  The Chaera inhabited the accretion disc's larger fragments.

  In the Ancestor's recorded images, Chaera were everywhere, spinning like frisbees over the surface of their worldlets, or whipping through the accretion mush to a neighboring fragment, or basking like lizards, their undersides turned up to the black hole.

  The beam from "God" had left a track of glowing debris through the accretion disc, like flesh scorched by hot iron. The track ended in a knot of larger fragments.

  In the optical imager, jellyfish bodies drifted like soot flakes.

  "Let me get this straight," Madeleine said. "The Chaera have evolved to feed off the X-radiation from the black hole... from 'God.' Is that right?"

  "Evolved or adapted. So it seems," Nemoto said dryly. " 'God provides us in all things.' "

  "So the Chaera try to... shout... to 'God,' " Ben said. "Some of them pray. Some of them build great artifacts to sparkle at Her. Like worshiping the Sun, praying for dawn. Basically they're trying to stimulate X-radiation bursts. All the Gaijin have done is to sell them a more effective communication mechanism."

  "A better prayer wheel," Madeleine murmured. "But what are the Gaijin interested in here? The black-hole artifact?"

  "Possibly," Nemoto said. "Or perhaps the Chaera's religion. The G
aijin seem unhealthily obsessed with such illogical belief systems."

  "But," Madeleine said, "that X-ray laser delivers orders of magnitude more energy into the artifact than anything the Chaera could manage. It looks as if the energy of the pulse they get in return is magnified in proportion. Perhaps the Chaera don't understand what they're dealing with, here."

  Nemoto translated. " 'God's holy shout shatters worlds.' "

  The main star was very Sunlike. Madeleine, filled with complex doubts about her mission, pressed her hand to the window, trying to feel its warmth, hungering for simple physical pleasure.

  There was just one planet here. It was a little larger than the Earth, and it followed a neat circular path through the star's habitable zone, the region within which an Earthlike planet could orbit.

  But they could see, even from a distance, that this was no Earth. It was silent on all wavelengths. And it gleamed, almost as bright as a star itself; it must have cloud decks like Venus.

  On a sleep break, Ben and Madeleine, clinging to each other, floated before the nearest thing they had to a picture window. Madeleine peered around, seeking constellations she might recognize, even so far from home, and she wondered if she could find Sol.

  "Something's wrong," Ben whispered.

  "There always is."

  "I'm serious." He let his fingers trace out a line across the black sky. "What do you see?"

  With the Sun eclipsed by the shadow of the FGB module, she gazed out at the subtle light. There was that bright planet, and the dim red disc of rubble surrounding the Chaera black hole, from here just visible as more than a point source of light.

  "There's a glow around the star itself, covering the orbit of that single planet," Ben said. "Can you see?" It was a diffuse shine, Madeleine saw, cloudy, ragged-edged. Ben continued. "That's an oddity in itself. But –"

  Then she got it. "Oh. No zodiacal light."

  The zodiacal light, in the Solar System, was a faint glow along the plane of the ecliptic. Sometimes it was visible from Earth. It was sunlight, scattered by dust that orbited the Sun in the plane of the planets. Most of the dust was in or near the asteroid belt, created by asteroid collisions. And in the modern Solar System, of course, the zodiacal light was enhanced by the glow of Gaijin colonies.