Exultant dc-2

by Stephen Baxter

  Nilis demanded, “Then how do you know the bones of your theory support any meat, eh? And besides, you’re describing spherically symmetric solutions of the equations. If I were to find myself inside a gravastar I would be as cut off and trapped, not to mention doomed to incineration by the shock wave, as if I were in a common black hole! So, Commissary, what use is any of this?”

  Draq was clearly nervous, but he fixed his smile like a weapon. “But that’s why we need the Silver Ghosts, Commissary. To go beyond human theory. And to give us experimental verification…”

  Nilis joined Draq under his imploding Virtuals, and they launched into a complex and convoluted argument, involving asymptotically matched solutions of partial differential equations and other exotica. Pirius had a pilot’s basic grasp of mathematics, but this was far beyond him.

  Mara approached him. She had her hands tucked into the sleeves of her robe. She whispered, “All this is a little rich for my blood, too. Perhaps we should take a walk.” She wouldn’t meet his eyes.

  “You don’t want to be with me.”

  “No, I don’t,” Mara said. “But it’s my duty to host you. And it’s your duty to understand what we’re doing here on Pluto—”

  “Don’t talk to me about duty.”

  “ — even if that means you’re going to have to confront your feelings about the Silver Ghosts.”

  “Why have I got to ’confront my feelings?’ “ he snapped. “The Ghosts shouldn’t be here. That isn’t a feeling. It’s a fact.”

  “What are you scared of?” she asked blandly.

  “That’s a stupid question.”

  She didn’t react. “It probably is. Will you come?”

  He sighed. It was her, or Draq’s partial, differential equations. “All right.”

  Suited up, they walked out of the dome. Mara led him perhaps half a kilometer away from the domes of the Christy compound. They didn’t speak.

  Once more, the sharp-grained, ultracold frost of Pluto crunched beneath Pirius’s feet, and he tried not to be spooked by the immense mass of Charon poised silently above his head.

  They crossed a low ridge, perhaps the worn-down rim of another ancient crater, and approached a new structure. It was an open tangle of cables, wiring, small modules; it looked impractical to Pirius, more like a sculpture. But it seemed oddly familiar, and he dug for the memory, left over from some long-ago training session.

  Mara spoke at last. “You understand that the main Ghost reservation, which you saw, is on the far side of the planet. But it was necessary to provide support facilities for the Ghosts who work with us here, at Christy. We decided to take the opportunity to recreate another bit of Ghost technology.”

  Then Pirius saw it. “This is a cruiser,” he breathed. “A Ghost cruiser.” Once, millions of ships like this had patrolled the Orion Line, the Ghosts’ great cordon flung across the face of the Galaxy.

  The Ghost ship was kilometers long, big enough to have dwarfed the greenship Pirius’s future self would have piloted in the Core. It had nothing like the lines of a human craft. The cruiser was a tangle of silvery rope within which bulky equipment pods were suspended, apparently at random.

  And everywhere there were Silver Ghosts, sliding along the silver cables like beads of mercury.

  “Of course it’s just a mock-up,” Mara said. “Basically life support. There are no drive units; it can’t fly. And no weapons! I always think it looks more like a forest than a ship. But that’s what it is, in a sense. The Ghosts are like miniature ecologies themselves, and they turned slices of their ecology into their ships. I’ve always thought that was a much more elegant solution than our own clunky mechanical systems.”

  Pirius felt that deep anger welling again. “Millions of human lives were lost in the defeat of ships like this. And you’ve built a, a monument to our enemy.”

  “Yes,” she said testily. “As you’ve said before. But don’t you think we need to understand what it was we killed?”

  He thought he didn’t understand her at all. “Is that why you’re here? Were you always so curious about Ghosts?”

  She hesitated, perhaps wary of giving away too much of herself. “I suppose so — yes. I’ve always been a Commissary. I started in the Office of Doctrinal Responsibility: very dry work! I was always blighted by curiosity. Not a good characteristic in the Commission for Historical Truth.” Her smile, behind her visor, was thin. “Then I found out about this facility, and a number of others, where life- forms generally supposed lost during the Assimilation have been preserved — or, as in the case of the Ghosts, revived.”

  “There are others?… Never mind. How did you find out?”

  She smiled again. “The control of the Commission isn’t as complete as some like to imagine. Truth finds a way. So I volunteered to come here. The powers that be were surprised, but they processed my application. Pluto is generally a punishment detail, you know. You come here to make amends, to end your career — certainly not to progress it.”

  “And was it worth it?”

  “Oh, yes, Ensign. It was worth it.” She led him around the periphery of the mocked-up cruiser. “I mean, look at this. What’s fascinating about the Ghosts to me isn’t their technological capabilities but their story: their origin, their account of themselves. You know, the Ghosts call the sky the Heat Sink — the place the heat went.” Since their world had frozen, Mara said, the Ghosts had not been shaped by competitive evolution, as humans had, but by cooperation. “They are symbiotic creatures. They derive from life-forms that huddled into cooperative collectives as their world turned cold. Every aspect of their physical design is about conserving heat, precious heat.

  “And they seem to be motivated not by expansion for its own sake, as we are, but by a desire to understand the fine-tuning of the universe. Why are we here? You see, Ensign Pirius, there is only a narrow range of physical possibilities within which life of any sort is possible. We think the Ghosts were studying this question by pushing at the boundaries — by tinkering with the laws which govern us all.”

  “But that made them dangerous.”

  “Yes,” Mara said. “An enemy who can use the laws of physics as a weapon is formidable. But they developed their capabilities, not as some vast weapons program, but for their own species imperative. Until they ran up against humans, it had nothing to do with us…”

  Pirius sensed movement behind him. A Silver Ghost hovered massively, a few meters away, just above the ice surface.

  Mara said quickly, “It’s only the Sink Ambassador. It must have followed us. It’s probably curious.”

  “Curious? You talk as if it’s a child.” Pirius saw himself reflected in the Ghost’s complacent hide. “You,” he said. “You are the Sink Ambassador?”

  “That is what I am called.”

  “Is she right? That you Ghosts follow your own logic, that you care nothing for humans?”

  “I don’t know,” the Ghost said. “I have no reliable data on the past.”

  Mara said dryly, “These new Ghosts won’t believe a word we say about their history. Maybe they’re right not to.”

  “We destroyed you,” Pirius said. “And we brought you back. Everything about you is in our power.”

  “True. But that doesn’t alter my perception of you.”

  Fists clenched, Pirius stepped up to the Ghost. Suddenly all the complex emotions he had been feeling — his inbred hatred of the Ghosts, his confusion at the reaction of Mara and the others, all that had struck him so overwhelmingly since the day his own future self had docked at Arches — welled up in him. And here was a Silver Ghost, right in front of him. He said on impulse, “Perhaps Mara is right. Perhaps I must learn about you, as you have learned about humans.”

  Mara was disturbed. “What are you doing, Ensign?”

  “Remove your hide. Disassemble yourself. Show me what you are.”

  Mara laid a gloved hand on Pirius’s arm. Her eyes were bright with anger. “I knew I shouldn’t have broug
ht you here.”

  Pirius shook her off. “I command this Ghost. I am human.”

  The Ghost was motionless, save for its usual subtle wafting, and Pirius, shaking with anger, wondered what he would do if the Ghost refused. He remembered his training on how to fight a Ghost. That hide was tough, but if you used all your strength you could get your knife into it, and then you could use the Ghost’s own rotation against it and open it up…

  The Ghost’s hide puckered, and shallow seams formed, stretching from one pole of the glistening sphere to another, segmenting the surface. The Ghost quivered briefly — then one seam split open. A sheet of crimson fluid gushed out, strikingly like human blood. It had frozen into crystals long before it fell to the Pluto ice.

  A Virtual of Nilis coalesced with a snap. “Stop this.” He stood between Pirius and the Ghost. “You, Ambassador. Heal yourself.”

  The gash in the Ghost’s hide closed, leaving only a pale scar. A stark slick of frozen blood showed how much it had lost in those brief moments.

  Nilis turned on Pirius. He thundered, “What were you thinking, Ensign? To deal with this I have been forced to leave a meeting I crossed Sol system to attend! Is this really your highest aspiration — the highest achievement of mankind, after twenty thousand long years of interstellar conquest — to use your petty power to cause another sentient creature to destroy itself? Why?”

  Because it’s what I’m trained to do, Pirius thought helplessly. But he flinched from Nilis’s furious glare.

  “Who is it you’re angry at, Ensign?” Mara asked. “The Ghost? Or is the Ghost just a target? Perhaps you are angry at the lies that you have been told throughout your life. Now you have been brought to Sol system you see the truth, and you can’t handle your rage. But you don’t know who to blame.”

  “Shut up,” Pirius said.

  “Perhaps you would rather have died in combat, without having to deal with such complex truths—”

  “Shut up!”

  Unexpectedly the Ghost spoke. Its translated words were as toneless as ever. “I gladly obeyed the ensign’s command. I am not afraid to die.”

  Nilis turned and inspected the Ghost. “Is that really true?” In an instant, Pirius saw resentfully, he had forgotten Pirius, and was taken over once more by his own endless curiosity. “But what consolation can there be for death? Tell me, Ghost — do you have gods?”

  Mara warned, “All it knows of its culture is what we have taught it. As if the Ghosts studied a human religion, filtered it through their own preconceptions and gave it back to us.”

  “Yes, yes,” Nilis said impatiently. “I understand that. Nevertheless—”

  The Ghost said, “Not gods of the past.”

  “No,” said Nilis rapidly. “Of course not. Human gods were creators. But your world betrayed you, didn’t it? What creator god would do that?”

  “The past is a betrayal. The future is a promise.”

  Mara said, “Commissary, we have tried to study Ghost philosophy. The Ghosts have a different perception of the universe than us, a different story about themselves to tell. Nobody’s really sure if concepts like religion actually map across to such alien minds.”

  “Oh, of course,” Nilis said. “But I’m of the school that holds that something like religious concepts must arise in any sentient form. Perhaps all mortal creatures, humans or Ghosts, must develop a philosophy to cushion the shock of imminent personal death.”

  Mara nodded. “I’d certainly concede that religious beliefs have survival value — and are likely to play an evolutionary purpose.”

  “Yes, yes! Religion provides a rationale for existence in a universe which may otherwise seem chaotic — perhaps an illusory rationale, but a way to cope. And religion has a function as social cement. Cooperation is essential, and religion fuels conformity. Really, religion ought to be a universal…”

  As this academic talk went on, Pirius glared at the wounded Ghost, and he imagined it glared back. Pirius said, “I don’t care what it thinks about gods. I want to know what it thinks of the humans who destroyed its kind.”

  Nilis and Mara tensed, but waited for the Ghost’s answer.

  The Ghost said, “You are the ones who kill.”

  Nilis said quickly, “Others kill too. The Xeelee kill. You kill.”

  “Only other kinds. No Ghost would kill another Ghost; it would be a kind of suicide.”

  Mara said, “The Ghosts think human war is insane — not just the war in the Galaxy, all our organized wars. Only humans spend the lives of others of our kind as if they were mere tokens. The Ghosts think nothing is so precious as sentience.”

  “Humans aren’t killers,” Pirius said. He lifted his hands. “We didn’t choose this war. Before we left Earth humans didn’t wage war at all.”

  Nilis actually laughed. “Ah, Ensign — another Coalition myth! Don’t pay attention to what the political officers tell you. Before spaceflight, despite the lessons of your childhood, Earth was not a paradise, where humans ruled other creatures in a kind of benevolent despotism; we were not noble savages. We have always killed, Ensign, always waged war — and as we had no alien enemy to kill in those days, we turned on each other. The proof is in the bloodstained ground of Earth.”

  Pirius pointed at the Ghost. “Commissary, don’t you get it? This is why this experiment, this revival of the Ghosts, is so wrong. We’re already arguing! Give them a chance and they will worm their destabilizing ideas into our minds.”

  Nilis was studying him; Pirius had the cold feeling he had become just another fascinating specimen to him. “Perhaps. But there will be no killing today.”

  Mara pointed upward. “Look.”

  Pirius, stiff in his skinsuit, tilted back and peered up.

  The patient bulk of Charon hung suspended over its parent, half-shadowed, a misty form in the light of the pinpoint sun. But now, right at the center of its face, a spark of light had erupted, blue-white, intense — far brighter than Sol. When Pirius looked away, he saw the new light was casting shadows,

  knife-sharp.

  Nilis clapped his hands with childlike excitement. “That’s the gravastar! What we see is the glow of infalling matter, shedding its gravitational energy as it hits the ultra-relativistic wave front. It’s really a remarkable technical achievement — the parameters of the controlled implosion of matter needed to create the shock are terribly narrow — stability is difficult to maintain.” He sighed. “But the Ghosts always were good at this sort of thing.”

  Mara said, “The test is being run on Charon. This is an experimental technology, and the energies involved are immense. There’s nobody up there to be hurt. Nobody but a few Ghosts, of course.”

  “Remarkable,” Nilis said again, peering up. “Remarkable.”

  That pinpoint of light, reflected, slid over the Ghost’s hide now. It was impossible for Pirius to believe that that starlike object, that bit of fire, was in fact far colder even than the ice of Charon itself.

  They returned to the dome.

  Nilis showed Pirius a summary of the rest of Draq’s briefing, and Pirius, his head full of anger, tried to pick his way through the jargon.

  He said, “But, Commissary, I still don’t see what use this is. You said yourself that if you got stuck inside a gravastar’s horizon you would be as cut off as if you fell into a black hole — and just as dead.”

  “Of course. A shock wave in the shape of a closed surface, spherical or not, would be no use to us. But Draq and his team, working with the Ghosts’ theoreticians, have come up with another solution.

  “Imagine that the shock front is not closed, but open — not a sphere, but a cap. Behind it you have your expanding captive universe, just as before, and where the expansion meets the infall you get your shock wave, the cap. But this toy cosmos isn’t symmetrical. At the rear, away from the cap, the curvature flattens, until asymptotically you have a smooth transition to an external solution…”

  Pirius thought he understood. “So you hav
e your cap of gravastar horizon,” he said carefully. “That’s lethal; you can’t pass through it. And behind it is a zone that is still effectively another universe. But if you approach from the rear, you would move through a smooth bridge from our universe into the captive one—”

  “Smooth, yes, save for the detail of a little tidal pull and so forth,” Nilis said.

  Pirius wondered how much trouble there would be in that “detail.”

  Nilis beamed. “Now do you see the potential, Pirius? Now do you see the application?”

  “No,” said Pirius frankly.

  “The toy universe is not causally connected to ours. And that means it wouldn’t be possible for the Xeelee, or anybody else, to have foreknowledge of what we might hide there — even in principle — because, you see, we’ll be tucked inside another universe altogether!”

  With a triumphant wave, Nilis brought up a Virtual copy of Pirius’s old sketch of the assault on the Prime Radiant: the journey in, bedeviled by FTL foreknowledge, the Xeelee ring of fire around the Prime Radiant itself, and then the mysterious Radiant at the heart of it all, sketched as a crude asterisk by Pirius. All of this was in red, but now Nilis snapped his fingers. “Thanks to Torec’s CTC computer, we can outthink the Xeelee when we get there.” That crimson ring around the Radiant turned green. “With the gravastar technology we should be able to stop foreknowledge leakage.” The inward path became green too. “Now all we need is a way to strike at the Prime Radiant itself.” Smiling, he said, “See what you can achieve when you focus on a goal, Ensign? See how the obstacles melt away before determination? Now — what would you suggest as a next step?”

  Pirius thought quickly. “A test flight. We need to modify a ship. Equip it with the gravastar shield and CTC processors. See if we can make the thing fly.” He grinned; for a pilot it was quite a prospect.

  “Yes, yes. Good!” Nilis slammed his fist into the palm of his hand. “That will make those complacent buffoons in the ministries sit up and take notice.”