Exultant

by Stephen Baxter

  As the waves converged, blue-white light flared, dazzling. The flash dissipated immediately—but now a concentrated knot of distortion was traveling along the axis of the rig. Shifting, oscillating, the distortion made the stars blur as it traveled. It was like an immense drop of water, Pirius thought. As it burst from the rig the knot broke open struts, and sent the scavenged GUTdrive engines flying—and it was aimed straight at the nightfighter.

  But before it had traveled more than a few hundred meters, the ball of distortion swelled up, burst silently, and dissipated.

  There was a rustle of movement in the corvette, a collective sigh of disappointment.

  Darc clapped Nilis on the back. “Scratch another run. Never mind, Commissary. We’re not done yet.”

  “Indeed not.”

  Torec said to Pirius, “Timing is everything. The implosion in the center is what we’re trying to design. If the amplitude is large enough, you get nonlinearity—a shock wave, its profile distorting as it travels, what the techs call a ‘classical scalar wave.’ I think we’ve got the amplitudes right, but not the timing. If the waves don’t converge right at the center, they just pass through each other harmlessly.”

  Pirius said, “And if the timing is right—what’s supposed to happen?”

  Torec stared at him, the first time she’d looked at him directly since he had got here. “You were on Callisto, and you don’t know?”

  Pirius said helplessly, “I just did my job there.”

  “This is a design from the Occupation era. It’s a black-hole cannon, Pirius.” She smiled faintly. “Can you believe that? We’re making a cannon to fire black holes at the Xeelee. And you know what else? It was designed by Friends. Friends, just like Enduring Hope!”

  Pirius, stunned, stared at the battered test rig. The techs and drones were already going back to work.

  Nilis asked Pirius to spend some time with him.

  They sat together in Nilis’s cabin. It was clear to Pirius that the Commissary wanted something. But Nilis was still guilty about how Pirius had been “used” on Callisto, and he seemed to want to make it up to him by talking to him.

  He said his “Callisto weapon” did indeed date from the time of the Qax Occupation. Pirius was amazed that the Friends of Wigner, in his day an illegal fringe cult out on Arches, had roots that deep.

  Back then the Friends had been a group of rebels on Earth. During the early phase of the Occupation, the control of the Qax had been relatively light—and remarkably enough, the Friends had been able to assemble a whole spacecraft, equipped with black-hole cannons, under the noses of Earth’s occupiers.

  The Friends had known that a wormhole bridge to the deeper past was soon to be opened; spanning fifteen centuries, this audacious stunt had been set up by none other than Michael Poole. When the bridge opened, the Friends hurled themselves and their ship into the past. Ignoring the humans of Poole’s time, they had set to work preparing their battery of black holes—but their purpose was not to use their cannon as weapons. Their target was Jupiter. In the guts of the gas giant these grenades of twisted spacetime would collide and merge, each collision sending out pulses of gravitational waves. By programming this sequence, the Friends hoped to shape the collapse of Jupiter, and so sculpt the final black hole that would result.

  “So that was what happened to Jupiter,” Pirius said.

  “Yes. Quite a monument!”

  “But if they could make black-hole cannons, if they could go back in time, why not just fly out to the Qax home world and wipe them out?”

  Nilis smiled. “Spoken like a true pragmatist! But the Friends’ objective was more philosophical… .”

  The first Friends of Wigner had taken their name from an ancient philosopher who had pondered the mysteries of quantum physics. Beneath the world perceived by humans was a scaffolding of uncertainty. Quantum functions pervaded space, each a description of the probability governing a particle or system; it was only when an observation was made that a particle could be pinned down to a particular place, or to a definite speed.

  “But this ancient philosopher, Wigner, took that logic a step further,” Nilis said. “Any observer is herself a quantum object—everything is, we all are—and therefore herself subject to quantum uncertainty. You need a second observer to make her real, and thence to make her observation real. If Wigner is the first observer, his friend is the second.”

  Pirius thought that over. “But what about the friend’s quantum function? That isn’t made definite until a third observer makes an observation of her.”

  “You have it,” said Nilis approvingly. “And then you need a fourth, and a fifth.”

  Pirius’s head was swimming with infinities. “But no matter how many observers you have, how many friends of Wigner you line up, you always need one more. So nothing can be real.”

  “This was called the paradox of Wigner’s friends,” Nilis said. “But the Friends believed they had a resolution.”

  The chains of unresolved quantum states will build on and on, growing like flowers, extending into the future. At last the great chains of quantum functions would finally merge at the last boundary of the universe, at timelike infinity.

  “And there, argued the Friends, will reside the Ultimate Observer, the last sentient being of all. All quantum functions, all world lines, must terminate in the Observer—for otherwise, she would not be the last. The Observer will make a single climactic Observation—”

  “And the chains of observations will collapse.”

  “History will be made real at last, but only at its very end.”

  Pirius said, “But I don’t see how this was going to help the Friends get rid of the Qax.”

  The Friends had come to believe that the Ultimate Observer might not be a passive eye, but that this final being might have a choice: that she might be able to exert an influence on how the chains of quantum functions were collapsed, on which cosmic history out of the many possible was selected.

  “And if a being has such power,” Nilis said, “perhaps she can be lobbied. And that was what the Friends intended to do. They were going to send the Ultimate Observer a message.”

  “How? With Jupiter?”

  “Singularities themselves have structure, you know. The singularity at the heart of the Jupiter black hole was to be shaped, and loaded with information. It would be a plea to the Ultimate Observer. The Friends wanted the Observer to select her chosen history to favor humanity—in particular, to pick out a causal line that would not include the Qax Occupation.”

  Pirius thought that over, and laughed, wondering. “That’s astonishing.”

  Nilis said, “It’s a terribly nihilistic philosophy—don’t you think? Just like their modern intellectual descendants, the Friends actually seem to have believed that they, their memories, their whole lives would be wiped out of existence when the Ultimate Observer makes her choice and some optimal timeline is plucked out of the quantum tangle. The Friends were not just escaping the Qax, Ensign. Perhaps they were escaping from themselves.”

  Pirius wasn’t convinced. He thought of Enduring Hope, back in the Core; if you were stuck in the middle of an endless war, the notion of an end-of-time arbiter who would one day delete all the pain from the world was a comforting idea.

  But he had believed it was myth. He hadn’t known that this airy nonsense about a cleansing at the end of the universe might actually have some physics in it. It was a spooky thought.

  “Of course their scheme was overcomplicated, and it didn’t work,” Nilis said. “The Friends didn’t even manage to make their black hole properly, let alone send their plea to the end of time. They managed to destroy Jupiter, though.”

  The Qax responded to the treachery of the Friends with devastating force. No longer would their rule be light; no longer could human cultural artifacts be used to camouflage rebellion. The Extirpation began: human history would be deleted, human minds wiped clean, even the fossils in the ground would be pulverized. The Qax
intended that humans would never pose a threat to the Qax again. They came close to succeeding.

  The Friends’ black hole technology was suppressed. And after the Occupation, when the Coalition came to power, such ancient horrors were suppressed again. But a handful of pharaohs kept the old knowledge alive, tucked away where even the long arm of the Commission for Historical Truth could not find it. The pharaohs had always known a day would come when it would be needed again.

  They fell silent.

  “I have a new assignment for you,” Nilis said hesitantly. “You might find it sticky.”

  “Sticky?”

  “I need you to think about Pirius Blue.”

  Pirius hadn’t thought about his temporal twin for days. “Why?”

  It turned out that Blue had been having adventures of his own. Astonishingly, he had flown a ship deep into the Cavity, to scout the Prime Radiant itself.

  “I’m trying to build up a picture of Chandra—its nature, its surrounds,” Nilis said earnestly. “I have the material I discovered in the Olympus Archive, the data from the neutrino telescope, and now Blue’s firsthand experience. I need to put it all together—to assemble a theoretical model of our objective. I was there, you know,” he said with a sort of modest pride. “In the Cavity. I sent in an avatar to ride with Pirius Blue. I like to think I acquitted myself well enough! But even that experience isn’t enough. I need to know what Blue himself perceived.”

  Pirius nodded slowly. “So why don’t you talk to him?”

  “It is a question of nuances,” Nilis said. He reached out his big hands toward Pirius. “I’m not sure I understand you, you see. We discussed this before. Our backgrounds are so different! Of course nobody knows Pirius Blue as well as you do. Nobody will be able to understand his words, his body language—what remains unsaid—as well as you. This is very important. Listen to your time brother, Pirius Red; listen to his feelings… .”

  Pirius took the assignment.

  For the rest of the day, he sat in Nilis’s musty cabin watching Virtual recordings of Pirius Blue, more battered, more weary, even older, as he described his extraordinary jaunt into the core.

  Pirius Red still felt a lingering resentment at this stranger from the future who had sent him into involuntary exile. But mostly, Red felt envy: envy for a man who had once more had the opportunity to carry out his duty in the most testing of circumstances, and envy for the companionship of his crew. Watching this scratchy Virtual report, Pirius Red felt shut out, denied.

  At the end of the day, Torec and Pirius retired to their small shared room on the corvette. They didn’t speak.

  Pirius stripped off his uniform and allowed it to slither into the closet. He got into his bunk, turned his face to the wall and closed his eyes, hoping for sleep. At least he wasn’t on Earth; at least he was back in space, and he could hear the comforting sigh of cycled air, feel the thrumming of the corvette’s drive.

  He was surprised when Torec slid into his bunk.

  He turned to face her. Her face was so close he could feel her breath on his cheek. Her eyes, dimly visible in the low light, were closed, her mouth tight shut.

  He put his hand on her arm. He felt firm flesh and muscle. He whispered, “Things aren’t the same.”

  He could feel her roll onto her back. “The trouble is, Pirius, things have changed for me. While you’ve been away, I’ve been useful.”

  He knew that was true. There had been her work on the CTC processor, the test flights of the modified greenships, even this early work on the black-hole cannon. He remembered her confusion when they had first been brought to Sol system, when she hadn’t even wanted to get out of bed.

  She said, “I know it’s chance that I’m here at all. It could have been anybody.” She shifted again. “Look, Pirius, I might have been brought here for you. But now I’ve found my own place. That’s what I’m trying to say. You can’t come swanning back and expect things to be as they were before.”

  “I don’t think I ever did expect that,” he said.

  “Then what?”

  He shrugged. “I need you.”

  She snorted. “Yeah. For sex.”

  “Not just that.” He hesitated to say the word, knowing it sounded soft. “Company.”

  She laughed. “What are you, a Coalescent drone? Life isn’t about company, Pirius. It’s about doing your job.”

  Defensively he said, “Yes. But maybe we can help each other to be more effective. Have you thought of that?”

  “What help do you need? It wasn’t even you who was sent into that weird other-place on Callisto.”

  “It was a copy of me who went off and died, to spare me having to do it. Just as Pirius Blue is a copy of me, who saw friends die in action, who went back into the Core again—and because he lived through that, I won’t have to. All these copies of me, taken away to die. And I’m left standing here.”

  “This talk is stupid.”

  He whispered, “Or perhaps I’m not real. Pirius Blue could have died out there, at the magnetar. What if he did die? What if I’m just his ghost? Or perhaps I’m existing in somebody else’s memories, or dreams. Perhaps Pirius Blue dreamed of Earth before he died, and everything I think is happening to me is happening inside his mind, in the last fraction of a second before the starbreaker hits—”

  “And maybe you’ve got your pointy head so far up your own ass it’s coming out the other end.” She pinched his kidney, hard enough to make him yelp. “Is that real enough for you?”

  Before she could do it again he rolled over and grabbed her. Laughing, they wrestled. He finished up above her, with his hands locking her arms above her head. Her face was a pool of soft shadows beneath him; she looked very young.

  He said, “You’re tougher than me. You always were. But don’t you feel … dislocated?”

  “Well, a little. But you tell anybody back on Arches I said so, I’ll kick your butt.”

  Hesitantly, he bent down, and kissed her, very softly, just brushing her lips. At first she was cold, unresponsive. Then she opened her mouth, and he felt the tip of her tongue on his teeth.

  Once again the test rig was readied for a fresh shot at the patient Xeelee nightfighter.

  It had been decided to try hooking up the CTC processor to the control systems of the test rig’s GUTdrive engines. It was possible that the CTC’s greater processing speed would permit the refinement of the control of the spacetime wave fronts sufficiently to get the result the designers wanted. Commander Darc railed at the foolishness of hooking up one experimental technology to another, but the CTC had already proven itself, in control of the grav shield. And as Nilis said, “Compared to the rest of this lash-up, CTC is a mature technology.”

  The work proceeded fast. Torec had as much experience as anybody with CTC systems, and so she had been drawn back into the heart of the project. Pirius was left stranded on the observation deck of the corvette, watching the techs work on the modified rig. It was easy to spot Torec, with her bright red team leader’s armbands over her skinsuit.

  Nilis stood with him. He waved a hand in the air, and brought up Pirius’s old Virtual sketch of the Project. The path to the Prime Radiant, the Xeelee barricade around it were green, the asterisk that represented the Radiant itself was glowing red. “What do you think, Ensign? Is today the day when we will find a weapon to strike at the Prime Radiant itself?”

  Pirius was embarrassed by the hubristic sketch. “I hope so, sir.”

  Torec’s voice sounded softly in Pirius’s ear. “Are you watching? Three. Two. One.” Pirius pressed his face to the hull.

  Again he saw flexing spacetime permeate the crude rig of struts and GUTdrive engines, again those waves of distortion washed into the heart of the rig. But the distortions seemed stronger to Pirius this time, their crowding propagation somehow more urgent.

  Purple-white light flared at the center of the rig, a glaring pinpoint. The framework itself pulsed and flexed, and struts snapped. But the frame held, and t
hat central pinpoint cast shadows over its complex structure. The pinpoint of light was a black hole. It was about as massive as a Conurbation dome, crushed into a space the size of an electron, glowing through Hawking evaporation at a temperature measured in teradegrees. It was working, then: he held his breath.

  For a second the black hole waited at the heart of the rig. The framework pulsed and cracked.

  And then the dazzling spark leapt straight out of the frame and hurled itself in a dead straight line across space to the Xeelee. When it hit, the nightfighter seemed to fold over on itself, as if crushed by a vast fist.

  For a long moment, nothing moved: the observers, Saturn’s broad disc, the crumpled Xeelee ship, the broken rig. Then, in Pirius’s monitors, remote cheering started.

  Nilis said, “My eyes. I think we’ve done it.” He snapped his fingers. On Pirius’s diagram, the crimson asterisk turned bright green.

  Chapter 34

  Conurbation 11729!

  It was a city known only by the number given to it by alien conquerors, but it was a number known throughout the Galaxy. This place had been the base of Hama Druz himself, twenty thousand years before. Ever since, it had been the beating heart of a human Galaxy.

  And it was here that Nilis and his team came to confront the mighty power that had ruled all mankind since Druz’s day, the Interim Coalition of Governance, seeking its blessing to establish a new Navy squadron and to equip it with upgraded ships, with CTC processors and gravastar shields and black hole cannons—seeking its blessing to take Project Prime Radiant to the center of the Galaxy itself.

  From the air the city looked almost ordinary, just another of the Qax’s inhuman clusterings of domes of blown rock. But the ancient blisters glittered with windows and balconies, the city was covered with a shining spiderweb of walkways and monorails, and steady streams of traffic, both intra-atmospheric and from space, washed through the ports that ringed the central dome cluster. The old Qax architecture was still the foundation of everything, but the sense of power here was palpable, even compared to the rest of Earth—power, and wealth.