Exultant

by Stephen Baxter

  Luru Parz said, “The biochemistry here is a matter of carbon-carbon chains and water—like Earth’s, but not precisely so. Energy flows thin here, and replication is very slow, spanning thousands of years. The cryptoendoliths themselves weren’t so interesting—except for one thing.”

  Reth had believed there were pathways of chemical and electrical communication, etched into the ice and rock, tracks for great slow thoughts that pulsed through the substance of Callisto. Locked into their ice moon, there had been few routes of development open to the cryptoendoliths. But, as always, life complexified, and sought new spaces to colonize. “The cryptoendoliths couldn’t move up or down, forward or back. So they stepped sideways… .”

  Nilis asked coldly, “Was Reth Cana an immortal, Luru?”

  “A pharaoh, yes. But not a jasoft, not a collaborator. He was a refugee, in fact; he came here fleeing the Qax, and waited out the Occupation. Of course, as soon as the Occupation was lifted, he became a refugee once more, hiding from the Coalition and its ideologies. He returned here to escape. And he helped others do likewise.”

  Pirius said, “What do you mean, these bugs grew sideways?”

  “I mean,” said Luru Parz, “that these remarkable little creatures found a way to penetrate another universe. And not just any old universe. Ensign, do you know what is meant by configuration space?”

  “Imagine there is no time. Imagine there is no space… .” In the still cold of Callisto, as she described extraordinary ideas, Luru’s voice was a dry rustle.

  “Take a snapshot of the universe. You have a static shape, a cloud of particles each frozen in flight at some point in space.” A snapping of fingers. “Do it again. There. There. There. Each moment, each juggling of the particles, gives you a new configuration.

  “Imagine all those snapshots, all the possible configurations the particles of the universe can take. In any one configuration you could list the particles’ positions. The set of numbers you derive would correspond to a single point on a mighty multidimensional graph. The totality of that graph would be a map of all the possible states our universe could take up. Do you see? And that map is configuration space.”

  “Like a phase space map.”

  “Like a phase space, yes. But of the whole universe. Now imagine putting a grain of dust on each point of the map. Each grain would correspond to a single point in time, a snapshot. This is reality dust, a dust of the Nows. Reality dust contains all the arrangements of matter there could ever be… .”

  Slowly, as Luru explained and Nilis tried to clarify, Pirius began to understand.

  Configuration space was not Pirius’s world, not his universe. It was a map, yes, a sort of timeless map of his own world and all its possibilities, a higher realm. And yet, according to Luru Parz, it was a universe in itself, a place you could go, in a sense. And it was filled with reality dust. Every grain of sand there represented an instant in his own universe, a way for the particles of his universe, atoms and people and stars, to line themselves up.

  But this was a static picture. What about time? What about causality?

  If you lined up reality dust grains in a row you would get a history, of a sort, Luru Parz said. But it might not make sense as a history; nothing like causality might emerge, just a jumble of disconnected snapshots one after another. But the sand grains attracted each other. If they came from neighboring points in the greater configuration space, the graph of all possible instants, the moments they mapped must resemble each other. And so the grains lined up in chains, each line of grains representing a series of instants which, if you watched them one after another, would give you the illusion of movement, the illusion of time passing—perhaps, if the grains were similar enough, even the illusion of causality.

  Something like that.

  And configuration space, he slowly understood, was where Luru Parz wanted to send Pirius.

  It was beyond his imagination. “You want me to go into a map? How is that possible?”

  Luru said, “Reth Cana discovered that, constrained in this space and time, the endoliths found a way into configuration space—and Reth Cana found a way for humans to follow. He could download a human consciousness into this abstract realm.”

  “I can see the appeal of that for pharaohs,” Nilis said with dark humor. “An abstract, static, Platonic realm—a place of morbid contemplation, a consolation for ageless pharaohs as they sought to justify the way they administered the suffering of their fellow creatures.”

  Luru Parz smiled thinly. “Of course it is a realm beyond our experience. So Reth constructed metaphors, a kind of interface to make its features accessible to human minds. There is an island—a beach. You’ll see a mountain, Pirius, and a sea. The mountain is order, and at its peak is that special dust grain that represents the initial singularity: the Big Bang, the unique event when all the universe’s particles overlaid each other.”

  Pirius said, “And the sea?”

  “The sea is the opposite. The sea is disorder—maximal entropy—the ocean of meaninglessness to which everything washes, in the end.”

  Pirius stood before the doorway, set up in the abandoned laboratory of Reth Cana. It looked as if it led nowhere. In fact, Luru Parz was saying, it led to a different realm of reality altogether. “And if I walk through this door—”

  “You will split in two,” Luru said. “You will still be here, walking out the other side. But a copy of you will be made.”

  “Like a Virtual.”

  “Yes. It will feel like you, have your memories. But it will not be you.”

  “And this copy will be in configuration space.”

  “Yes.”

  “But why must I go there?”

  “Because that is the place the pharaohs went. The pharaohs flocked there, from all over Sol system and beyond,” Luru Parz said. “Their knowledge—some of it preserved from long before the Qax Occupation—went with them, too. Configuration space is a black library—the final library—and it contains much we have lost.”

  Nilis said, “You chose not to follow these undying refugees into configuration space, Luru Parz.”

  Her face was blank. “Unfinished business,” she said.

  Pirius said, “And this lost knowledge is what you want me to bring back.”

  “Yes. The ancients had considerable powers. Don’t forget it was human action that turned Jupiter into a black hole. Perhaps they even knew how to land punches on the supermassive monster at the center of the Galaxy.”

  He understood. “You want me to find a weapon in there. A weapon to strike at Chandra, in this hideous old library of yours.”

  “Yes … but there’s a catch.”

  “A catch?”

  “Once in there, the refugees didn’t stay human for long. Which is somewhat inconvenient. Try to hold onto yourself, Ensign. Your identity. And stay away from the sea.”

  Pirius peered at the portal. “Will I be able to come back? I mean, uh, he—the Virtual copy.”

  Nilis strode up to him and took his shoulders. Pirius had never seen Nilis look so grave. “Pirius, I have taken you far from your home, your duty. I have asked you to face many extraordinary situations—and many dangers. But this is by far the most difficult thing I have ever asked you to do.”

  Pirius said slowly, “I can’t come back.”

  Luru Parz laughed. “But it doesn’t matter. Sentient or not, it will only be a copy, like a Virtual. And it won’t last long. It has to be you, Ensign.” She smiled, showing her blackened teeth. “You’re the only suitable resource we’ve got. I’m worn smooth with time, Nilis here is too aged … only you have the strength to endure this.”

  Pirius looked at the frame. He felt numbed, not even afraid; perhaps his imagination was exhausted. He shrugged. “There are already two copies of me running around the Galaxy. I suppose I’m used to being split in half. When shall we do this?”

  Luru Parz said, “The equipment is ready.”

  Nilis gaped. “Now? Just like tha
t?”

  “Why delay?” She stepped close to Pirius, so close he could smell her musty odor through the chill tang of the ice. “Do it, Pirius. Step through and it will be over. Don’t think about it. Just step through …” She was grotesquely seductive. He felt oddly compelled to obey. It was as if he had a gun in his hand, pointed to his head; no matter how rational he was there was always a trace of a compulsion to pull the trigger—and that self-destructive compulsion was what Luru Parz was working on now. “Do it,” she whispered, like a voice in his own head.

  Nilis said, “Oh, but this is so—I wish I could spare you this ordeal!”

  “It will only be a copy,” Luru said. “Not you. What does a copy matter?”

  Enough. Pirius turned away from Nilis. Luru Parz was right. If he had to do this—

  He stepped into the frame. There was a flare of light, electric blue, blinding him. He pushed forward further, into the light.

  He staggered. Gravity clutched at him, stronger than the ice moon’s wispy pull, as if inertial shielding had failed. The ground under his feet felt soft, dusty, like asteroid regolith.

  The blue glare faded. He stood stock still, and blinked until he could see.

  He was standing on sand, bits of eroded rock. He felt the gravity stress his bones, pull at his internal organs.

  He was here, then, in configuration space. He felt like himself. But he was the copy, projected into this strange realm, while another Pirius, the original, was back on the ice moon.

  He struggled with fear. Callisto was only seconds in his past, yet he could never go back. He somehow hadn’t imagined his impulsive action ending up like this—or hadn’t let himself imagine it—as Luru Parz had surely calculated when she talked him into this. And he didn’t want to die.

  “Lucked out,” he said to himself.

  He looked around. The sky above him was open—no roof, no dome. But he was used to that by now. The light was bright, but diffuse, shadowless, without a single source, without a sun.

  A mountain loomed over the horizon, a pale cone made misty by distance. The ground sloped gently toward a sea that lapped softly. But the sea was black, like a sea of hydrocarbons, as if this were Titan. He looked the other way and saw a tangle of some kind of vegetation. He dug the words out of his memory. Ocean. Land. This was a beach, then, an interface between land and the open ocean; he was on a beach.

  None of this was real, of course. All of these props—the beach, the ocean—were a rendering of a more profound reality into terms he could grasp. Metaphors, drawn from the human world. But not his world. This was an abstraction to suit a different mind, a mind that had grown up on Earth. This would have been a strange place to a Navy brat even if he hadn’t come here by such a strange route.

  But he had a mission. He was here to find a weapon that could strike at a galactic-center supermassive black hole. That was something to focus on. And maybe after that, he could find some way to survive after all.

  He turned and trudged up the beach, toward the vegetation. It was difficult walking on the sand, which gave with every step.

  The wall of vegetation that fringed the beach was thick, apparently impenetrable. He didn’t know much about plants, save what he had seen in Nilis’s garden. But then, this tangled bank was not a true forest; the plants that grew here were not “trees.” The trunklike shapes he saw, crowded with waxy, gray-green leaves, were each composed of dozens of ropelike vines, all tangled up together.

  When he looked down, he saw that the vines spread out into the dirt at the base of the vegetation. They did not dig into the ground like roots, though. Instead they spread over the surface, bifurcating further—until, he saw now, they blended into structures in the sand itself, at last dissipating altogether in a scattering of grains. It was a gathering of structure, he thought, rising from the sand, melding into these apparently living things.

  Luru Parz had told him none of this had anything to do with biology, but somehow, with causality, with chains of consequences gathering in significance …

  He was never going back.

  Suddenly the truth of it hit him, blinding him to the place in which he found himself. He probed for a sense of loss, of abandonment, found only numbness. He tried to think of other times, other places: the ancient ice mine on Callisto, and the deeper past beyond that, the worldlets of Arches Base, the dorms, the soft warmth of Torec. It took an effort, as if the brief moments he had been here were expanding to fill his life.

  After all, he remembered, he was a mere representation of somebody else. He wasn’t real, and that lost life had never been his. His fear faded.

  Luru had warned he might lose himself in here. Maybe losing his fear was the first stage of that. Real or not, he had his duty; that was real enough.

  Something rustled, deep inside the tangle of gray-green. He looked up, startled. Two eyes peered back at him—human eyes? But another rustle, a shake of the leaves as if a wind had passed, and they were gone.

  He plunged into the vegetation. “Wait,” he cried. “Wait!” He had to rip aside the tangle of vines by main force, and even so was barely able to move forward.

  There was a face before him. Two bright eyes, peering from green shadow. He froze, shocked. At first he could make no sense of it. He saw eyes, nose, a mouth. But the proportions seemed wrong—the eyes too close, the mouth too wide. Then it shifted, as if one face were melding into another, or a Virtual image were failing. But the eyes were steady, that gaze locked on his. Was it possible this was the relic of some jasoft, come here to flee from the Coalition?

  And was this a glimpse of his own fate?

  “Help me,” he said. It came out as a whisper, and he tried again. “Help me. Humanity is in peril. We need to strike at the Prime Radiant of the Xeelee. We need a way to harm a supermassive black hole.”

  It seemed absurd. What could such things matter here? What was a war, even, in a place where a handful of sand grains held a million possible instants? What indeed was life or death? And yet he remembered his duty; he tried to speak to that monstrous, shifting face. “If there is anything left of the human in you, you must answer—”

  A fist slammed into his face, with impossible force. He felt his nose crunch under the impact. And something was forced into his mouth, hard enough to tear the muscles of his cheeks.

  The blow hurled him backward, out of the forest, his hunched body ripping through the tangle of causality. He landed on the beach, sprawled in reality dust. And his hand was burning, as if he had dipped it in fire. The pain distracted him even from the ache of his shattered face, the bitterness of the stuff in his mouth. The black ocean was lapping close to him, much further up the beach than before. Tides, he thought. Secondhand gravitational effects, working on open bodies of liquid. Bits of facts from his training, from a life that was lost.

  He held up his arm. His hand was gone, the stump neatly filmed over with pink flesh, as if the hand had never been. The black stuff wasn’t water. It must have burned off his hand like the strongest acid. Neat it might be, but the pain was agonizing.

  Causality, he thought. Entropy. That’s what Luru said the sea means. I am being eaten by a sea of entropy, dissolved into disorder.

  He forced himself to roll over, away from the ocean. Pain lanced up his arm.

  The stuff in his mouth shifted, blocking his breathing. He could suffocate lying here. Or the blow itself might turn out to be lethal. There were ways to kill people like that, he remembered; you rammed your face into your opponent’s nose, to push a shard of bone into the brain.

  He was going to die here. But he was just a Virtual—not Pirius, not Pirius Red or Pirius Blue. He was Pirius Gray, he thought, Pirius the shadow. His death didn’t matter.

  His mouth worked. Perhaps he could spit the crud out from his mouth. But some instinct made him bite into it. A thick, acidic fluid spurted into his mouth. He bit again, and forced himself to swallow.

  Perhaps he had succeeded. He had come seeking answers, and he h
ad been given a cruel feeding. But what had he expected, a textbook? Some philosophers said that humans shouldn’t dream of contact with the Xeelee; their warmaking was the only possible contact. And perhaps this revolting mouthful was the solution he had been sent for.

  He tried to think of his name again. It was fading, fading like a dream in the moments after waking. Gray, gray.

  Pain striped along his left hand side. He cried out. The black ocean had washed a little further up the beach. He tried to scramble away.

  Deep inside Callisto, Pirius stepped into the door frame. There was a flare of light, electric blue, blinding. He pushed further forward, into the light.

  On the far side of the portal he felt a hard, cold surface under his feet. Ice?

  The blue glare faded. He stood stock still, and blinked until he could see.

  Suddenly his heart was hammering. He was still in the chamber, on Callisto, standing on the other side of the portal. He was Pirius, not the copy; he would have to leave that other to do his duty for him. “Lucked out,” he said.

  “My eyes,” said Nilis. “Oh, my boy, what a terrible thing …”

  Luru Parz said, “Look.”

  Pirius turned. A Virtual projection hovered over the service bot, a complex, fast-shifting display, elusive, dense. Even the Navy guard was staring.

  Pirius asked, “What is it?”

  “Data,” said Luru Parz. “From configuration space. Coming back through the portal.”

  “I think it worked,” Nilis said. “You found something, Pirius!”

  Luru Parz growled, “Now all we have to do is figure out what it is.”

  Chapter 32

  The flight approached the terminus of East Arm.

  The three main arms of the Baby Spiral, three fat streams of infalling gas, came to a junction, melding into a massive knot of turbulence. Pirius Blue could see it ahead, a tangle of glowing gas filaments. He knew that just on the other side of that central knot of gas lay the brooding mass of Chandra itself, and the powerful alien presences that infested it. No human crew had ever gotten so close and lived.