by Greg Egan
Suddenly, Tchicaya understood. Selman wasn't withholding his signature as a gesture of hostility, or in an attempt to conceal his identity. He had no signature, and no Mediator to send it. He had no Exoself. He had no Qusp. The rebels had improvised some kind of crude surgical tool, and plucked each other's digital brains out.
Tchicaya said, “Talk to me, and I'll find the right translator! We still have all the old languages.” He wasn't expecting to be understood, but he could still provoke a response. Assuming Selman hadn't lost the power of speech entirely. Tchicaya didn't know how much neural tissue a Homo sapiens needed in order to be fully functional. Bodies like the Rindler's had plenty of neurons in reserve, since the precise delegation of tasks between the digital components and the central nervous system varied widely from culture to culture. He suspected that even this reserve was less than the size of a complete ancestral brain, but a careful redesign might still have packed everything in.
With ten or twelve meters remaining between them, Selman stopped and spoke. Tchicaya couldn't even parse the speech into separate words; to his untrained ear it sounded like a continuous flow. This was the first time in his life that he'd begun a conversation with a stranger without the ground being prepared in advance, without two Mediators conspiring to bridge the gap. A moment after the utterance was complete, though, he recalled the sounds and understood them.
“Turn around and go back, or I'll beat you to a pulp.”
Tchicaya replied in the same tongue, or what he hoped was near enough to be comprehensible. His Mediator had traced Selman's words back to a language from twenty-third century Earth, but it was compensating on the fly for the kind of variations that could arise over millennia in an isolated population of the original speakers.
“As opposed to what? Turn around and go back, and fry with the ship?”
Selman said, “If the builders are willing to take the ship away from the border, no one has to fry.”
Tchicaya shrugged. “Flee or fry, it's all the same to us. The only thing at stake is access to the border, so every choice that would put an end to that is equivalent. You can fly us all the way to Earth, or you can crack our heads open one by one, but don't expect to get any more cooperation for one alternative than another.”
Selman said, “Spare yourself the pain, then. Or the mess, if pain is beneath you.” He stepped forward, swinging the bar. Tchicaya had no knowledge of martial arts; he delegated the problem to his Exoself, and watched the interaction as a detached observer until he was standing with one foot on the back of Selman's neck, and holding the bar himself.
“That wasn't even you, you bloodless worm!” Selman hissed.
“Oh, you noticed?” The other four were approaching; two of them were hefting large potted plants, a choice of weapon more alarming for its strangeness than its bulk. “None of this was necessary,” Tchicaya said. “Whatever grievance you had, we would have given you a hearing.”
“We gave our arguments peacefully,” Selman replied. “Hours ago.”
“What arguments? Evolutionary imperatives, and winning back territory? We're the ones who've lost two thousand systems. You haven't lost a single ship.”
“So you expected us to sit back and do nothing? While you betrayed your own species, and wiped out the last vestiges of humanity?”
Tchicaya was still struggling to come to terms with the rebels’ origins. To pass as ordinary travelers at all, they must have translated themselves into versions that ran on their Qusps, as well as their Trojan-horse brains. Lying in wait, impotently watching their other halves act, must have been a deeply unpleasant experience. The neural versions would not have been able to follow much, if any, of what was spoken around them—even when the words passed through their own lips—so the Qusp versions would have had to brief them later, whispering in private in their native tongue. Coming prepared to survive their own preemptive digital lobotomies had been prescient, though. Tchicaya was almost certain now that the builders possessed halt switches for all the ship's Qusps; that would have been the method they'd hoped to use against the rebels heading for the hub, before changing their mind and sending Rasmah and the others in pursuit.
The other four anachronauts stood before Tchicaya. One of them, Christa, said, “Let him go, and back away.”
“Or what? You'll beat me to death with your rhododendron?” Tchicaya asked the ship, “What is that? Is it one of yours?”
“Originally, but it's been tweaked.”
“Into something dangerous?”
“There's nothing obviously harmful being expressed in the leaves or stalk.”
“And the roots?”
“I have no way of knowing about the roots.”
Christa repeated, “Let him go, and back away. This is your last chance.”
Tchicaya asked his Exoself if it could relieve both rebels of their pots without spilling the contents. It could make no promises.
He said, “I have nothing to gain by retreating.”
Christa glanced down at Selman, her mask of grim resolve melting for an instant. She was stranded in a deranged, alien world, and she believed she was about to die.
Tchicaya said, “We can—”
She raised the pot to her shoulder, and started to shake the plant free. Tchicaya told his Exoself to keep as much as it could from falling; he sprang forward, grabbed the stalk, and forced the plant back into its container. As Christa toppled backward, his Exoself had him reach out with his other hand and secure the pot around the roots.
As he did this, in the corner of his eye he saw another anachronaut swinging the second plant by its stalk. The roots were already free of the pot, and the soil around them was falling away. Between the gnarled gray fingers of the roots were dozens of swollen white nodules. Tchicaya told his Exoself to prevent the nodules from coming into contact with anything solid. It knew how fast he was capable of moving, and how fast he needed to be. The task, it declared, was impossible.
The anachronaut slammed the roots of the plant down on the floor.
Tchicaya lost everything but his sense of motion. He was deaf and blind, falling, waiting for an impact. He'd been thrown into the air, so he had to come back down to the ground eventually. That made sense, didn't it?
The impact never came, but his vision was restored in an instant. His suit had turned fully opaque to protect his eyes; now it had decided that it was safe for him to see again. He was outside the Rindler, falling away from it. He could see the damaged walkway narrowing into two hourglass waists on either side of the ruptured section, pinching it off, stopping the flow of air. A skein of filaments was already beginning to crisscross the wound.
He looked around for the anachronauts. He spotted one in the distance, silhouetted against the borderlight, sharing the velocity he'd acquired from the Rindler's spin but separated from him by the force of the blast. The limbs were fixed at unnatural angles; he was looking at a corpse. All the ships' bodies could switch modes and cope without oxygen, but between the explosion and the exposure to vacuum there'd been no prospect of anyone surviving unprotected. The rebels had had more time than anyone else to think about putting on suits before endangering themselves, but they'd apparently decided not to bother. That was either willful martyrdom, or the expectation that, whatever happened, no one was going to be left alive to come and rescue them.
Branco spoke. “Are you all right?”
“I think so.” If his suit had been damaged at all by the blast, it had since repaired itself, and his Exoself reported nothing more than bruising to his body.
“I'll send the shuttle after you.”
Tchicaya said, “Thanks.” He waited, watching numbly as the necklace of the ship continued to recede. He was tumbling slowly around an axis that almost coincided with the direction of his motion; the Rindler never vanished from sight, but the horizon between the border and the stars wheeled in front of him.
Branco said, “Plan A might not be possible. They've glued the shuttle's release bo
lts in place.”
Tchicaya pondered this, dreamily amused for a moment. The sheer strangeness of his situation had induced a sense of detachment; it was a struggle to think his way back into events on the ship.
“What's happening at the hub?”
“We reviewed what the climbers were doing earlier, in the instrumentation bay,” Branco replied. “They were building a particle detector, with some powerful superconducting magnets. Which are now part of the devices they have with them.”
“The fuel must be shielded, though? Against stray magnetic fields?” The antimatter portion was kept in a purely magnetic container; that had to be robust.
“Do you have any idea how many orders of magnitude difference there is between stray interstellar fields and the strongest artificial ones?”
Tchicaya took this question to be rhetorical. “How close are Rasmah and the others?” He didn't want to look for himself; he just wanted Branco to give him the good news.
“They're close. But the rebels are already at the hub, setting things up.”
“And you believe they might be capable of spilling the fuel?”
“We can't rule that out. It will depend how good their device is. If they're smart, and if they have time, they could pump energy into two different flows that the containment fields couldn't restrain simultaneously.”
Tchicaya said nothing. He closed his eyes. He'd screwed up, he'd let his guard down with the anachronauts, but Rasmah was unshakable. She'd stop them, if she got the chance.
Branco said, “We're now seeing flows developing in the fuel.” His voice betrayed no hint of panic. After the loss of the Scribe, he'd told Tchicaya that he'd been through local death seven hundred and ninety-six times, but even if he was immune to existential qualms, the prospect of losing contact with the border had to be painful. “Listen to me carefully. There's no way we're going to get the shuttle free in the next few minutes, but we could use the debris-clearance laser to burn through the tether that's holding the module to which the shuttle is docked.”
“What good would that do? The whole module is swarming with rebels.”
“There are five known rebels—who we've managed to contain by reconfiguring some walls—but there are also three other people. All three are declared Preservationists, but they might still be your allies. If I throw the module clear of the Rindler, and everyone else is lost, they might get the shuttle free. And if the Rindler survives, at least they'll have a chance of getting back to us.”
Tchicaya said, “Who are the three?”
“Alejandro, Wael, and Mariama,” Branco replied. “I don't know any of them well. But you're the one who'd be left here with them, so you'd better decide whether that would be to your advantage or not.”
The retreating ship was vanishing into the borderlight. Tchicaya didn't want the power to gamble with anyone's fate, but the rebels had left the builders with no choice but to juggle odious alternatives, and now Branco had dragged him into the same quagmire.
If the rebels were trying to destroy the Rindler, it was because they believed they had nothing more to do here, which meant that the Right Hand was already primed to scribe Planck worms without further intervention. Sparing everyone in the module wouldn't put the far side in any greater danger, so he should err on the side of saving those people, in the hope that they'd help him fight the Planck worms. If he was left here alone, drifting off into the distance, he might be able to control the Left Hand remotely for a while, but without the shuttle he'd eventually lose radio contact.
The rebels could still be mistaken, though. The first attempt to create the Planck worms could fail. If anyone aligned with the rebels remained, they could work to rectify those early mistakes; they'd have decades to achieve their goal, virtually guaranteeing that the far side would be obliterated. So maybe it would be safer to be left alone, to do whatever he could in the time he had.
It all came down to whether or not one or more of those three people had been swayed by the rebels, as Birago had been swayed. Birago, who'd always seemed passionate but reasonable, and nowhere near as fanatical as Tarek.
Alejandro, Wael, and Mariama.
Branco said, “We've worked out the strategy the rebels are using. It's not the best, but it is effective. If they're not stopped, they'll definitely spill the fuel.”
Tchicaya said, “Cut it loose.”
He stared at the horizon, watching for some glint from the laser in action, but that was futile. He couldn't see any part of the ship anymore, and the portion of the tether that was glowing white hot would only be centimeters long.
“Branco?”
“Nearly there. It will take a few more seconds. Rasmah's just reached the hub. She's fighting with two of the rebels.” Branco chuckled “Make that one.”
Tchicaya's spirits soared. He asked the ship to show him the struggle.
There was no response. He asked again.
On the horizon, a dazzling bead of violet light appeared, outsining the border. Then his suit shut off his vision.
Chapter 14
When the first, paralyzing wave of despair had left him, Tchicaya tried to contact Mariama. Without success, but he'd steeled himself for that further small blow. He didn't know which way the module had been flung, but with every minute that passed both of them were six kilometers further from the point where the Rindler had been, and it was possible that they were already too far apart for direct Mediator-to-Mediator contact. The module would have its own longer-range transceivers, but it was possible that they'd been damaged by the radiation from the Rindler's fireball.
He had to be patient. If Mariama had survived, she would find a way to contact him.
Belatedly, it occurred to him to try the Left Hand. It responded. The vote Yann had spoken of had gone through in time: the Left Hand not only acknowledged his signal, it was willing to take instructions from him.
He had his Mediator construct a virtual replica of the familiar Blue Room console, and he placed himself before it. He merged Yann's toolkit with the interface, and summoned the first simple menu of possibilities. For several seconds, he was too afraid to do anything but stare at the screen. Then he scribed a probe that would enter the far side and return as quickly as possible.
Minutes later, the echo came back to him. The surface layer of the far side, at least, was unchanged, populated by exactly the same mix of vendeks as they'd seen with the first experiment.
He tried a deeper probe. The result was the same: nothing had changed.
Tchicaya left the scape. He watched the horizon hopefully, sifting through the possibilities. The rebels had chosen not to scribe the Planck worms before mounting their attack on the ship. Perhaps they'd feared that they'd encounter more determined resistance from their opponents, if the annihilation of the far side was already playing out right before their eyes. A premature assault on the border would also have weakened the position of the remaining Preservationists, if the mutiny had been crushed. In any case, the fact that they'd felt a need to destroy the Rindler implied that the rebels were not confident that the process would be unstoppable once it had begun.
If the rebels hadn't arranged for the loss of the ship to trigger the event immediately, there had to be some kind of timer counting down. If Mariama had got the shuttle free, she might have headed straight for the Right Hand, to pluck it out of the equation completely. If Birago had successfully corrupted it, the Right Hand would not take orders from her, and it was certainly more able to look after itself than the Scribe had been, dodging far larger shifts in the border. But Tchicaya doubted that it was equipped to defend itself from a determined assailant. The shuttle had more powerful engines; if it came down to brute force, she could probably bulldoze the Right Hand straight into the border.
If she reached it in time.
And if she was willing.
Three and a half hours after the loss of the Rindler, the border was transformed. Tchicaya didn't perceive anything approaching; he merely saw the ex
panse of white light replaced in an instant by an opalescent gray. He turned just in time to catch sight of the edge of the change as it vanished behind him.
The sphere of the border was so vast that the true geometrical horizon was a billion kilometers away, but to his unaided vision everything beyond about a million kilometers occupied a single line, too narrow to resolve. After replaying the event, his calculations could not rule out the possibility that the change had swept by at lightspeed. That would have made it literally impossible to see coming, and then the delayed evidence of the fleeing edge would have given the impression that it was traveling at half its true speed, crossing the million kilometers he could distinguish in about six seconds.
He checked with the Left Hand. Being closer to the border, its field of view was smaller than Tchicaya's, but its instruments left his senses for dead. It had tracked the change he'd witnessed, and judged it to be moving at the speed of light.
Not roughly, not nearly, but, to the limits of measurement, precisely the speed of light. Which meant that the Planck worms could not be pursued, let alone stopped.
The battle was over. The far side was lost.
Tchicaya caught himself angrily. The ability to move across the border at lightspeed didn't guarantee the power to penetrate the far side at the same rate. For all he knew, he'd just seen nothing more than a variation on Branco's surface-pinning effect.
He told the Left Hand to scribe another probe.
It couldn't. The border had retreated.
Retreated how far? The Left Hand couldn't tell him. How do you measure the distance to a featureless, immaterial plane of light? Once the border had slipped out of range of the particle beam of the stylus, the Left Hand had lost the ability to summon forth any kind of echo. It had scattered a small cloud of electronic fireflies, moving at about ten meters a second, to see when they were extinguished. So far, they all remained intact. It was no use tracking the brightness of the borderlight; each square meter of the border would seem dimmer as it retreated, but that effect was canceled out precisely by the fact that any particular instrument you aimed at it, with some fixed angle of view, would be taking in light from a larger portion of the border the further away it was. And there was no Doppler shift to reveal the velocity of retreat: the far side was being pared away, not pushed away, and the new, gray borderlight was being emitted from a succession of different surfaces, not a single moving source that could act as a clock.
