by Greg Egan
Silence.
Leila said, “All right. Forgive my impertinence. I have to tell you honestly, though, that we won’t be the last to bother you. The Amalgam is full of people who will keep trying to find ways to reach you. This is going to go on for another million years, until we believe that we understand you. If that offends you, don’t judge us too harshly. We can’t help it. It’s who we are.”
She closed her eyes, trying to assure herself that there was nothing she’d regret having left unsaid.
“Thank you for granting us safe passage,” she added, “if that’s what you’re offering. I hope my people can return the favor one day, if there’s anywhere you want to go.”
She opened her eyes and sought out her destination: deeper into the network, on toward the core.
10
The mountains outside the town of Astraahat started with a gentle slope that promised an easy journey, but gradually grew steeper. Similarly, the vegetation was low and sparse in the foothills, but became steadily thicker and taller the higher up the slope you went.
Jasim said, “Enough.” He stopped and leaned on his climbing stick.
“One more hour?” Leila pleaded.
He considered this. “Half an hour resting, then half an hour walking?”
“One hour resting, then one hour walking.”
He laughed wearily. “All right. One of each.”
The two of them hacked away at the undergrowth until there was a place to sit.
Jasim poured water from the canteen into her hands, and she splashed her face clean.
They sat in silence for a while, listening to the sounds of the unfamiliar wildlife. Under the forest canopy it was almost twilight, and when Leila looked up into the small patch of sky above them she could see the stars of the bulge, like tiny, pale, translucent beads.
At times it felt like a dream, but the experience never really left her. The Aloof had woken her at every node, shown her the view, given her a choice. She had seen a thousand spectacles, from one side of the core to the other: cannibalistic novas, dazzling clusters of newborn stars, twin white dwarfs on the verge of collision. She had seen the black hole at the galaxy’s center, its accretion disk glowing with X-rays, slowly tearing stars apart.
It might have been an elaborate lie, a plausible simulation, but every detail accessible from disk-based observatories confirmed what she had witnessed. If anything had been changed, or hidden from her, it must have been small. Perhaps the artifacts of the Aloof themselves had been painted out of the view, though Leila thought it was just as likely that the marks they’d left on their territory were so subtle, anyway, that there’d been nothing to conceal.
Jasim said sharply, “Where are you?”
She lowered her gaze and replied mildly, “I’m here, with you. I’m just remembering.”
When they’d woken on Massa, surrounded by delirious, cheering Eavesdroppers, they’d been asked: What happened in there? What did you see? Leila didn’t know why she’d kept her mouth shut and turned to her husband before replying, instead of letting every detail come tumbling out immediately. Perhaps she just hadn’t known where to begin.
For whatever reason, it was Jasim who had answered first. “Nothing. We stepped through the gate on Tassef, and now here we are. On the other side of the bulge.”
For almost a month, she’d flatly refused to believe him. Nothing? You saw nothing? It had to be a lie, a joke. It had to be some kind of revenge.
That was not in his nature, and she knew it. Still, she’d clung to that explanation for as long as she could, until it became impossible to believe any longer, and she’d asked for his forgiveness.
Six months later, another traveler had spilled out of the bulge. One of the die-hard Listening Party pilgrims had followed in their wake and taken the short cut. Like Jasim, this heptapod had seen nothing, experienced nothing.
Leila had struggled to imagine why she might have been singled out. So much for her theory that the Aloof felt morally obliged to check that each passenger on their network knew what they were doing, unless they’d decided that her actions were enough to demonstrate that intruders from the disk, considered generically, were making an informed choice. Could just one sample of a working, conscious version of their neighbors really be enough for them to conclude that they understood everything they needed to know? Could this capriciousness, instead, have been part of a strategy to lure in more visitors, with the enticing possibility that each one might, with luck, witness something far beyond all those who’d preceded them? Or had it been part of a scheme to discourage intruders by clouding the experience with uncertainty? The simplest act of discouragement would have been to discard all unwelcome transmissions, and the most effective incentive would have been to offer a few plain words of welcome, but then, the Aloof would not have been the Aloof if they’d followed such reasonable dictates.
Jasim said, “You know what I think. You wanted to wake so badly, they couldn’t refuse you. They could tell I didn’t care as much. It was as simple as that.”
“What about the heptapod? It went in alone. It wasn’t just tagging along to watch over someone else.”
He shrugged. “Maybe it acted on the spur of the moment. They all seem unhealthily keen to me, whatever they’re doing. Maybe the Aloof could discern its mood more clearly.”
Leila said, “I don’t believe a word of that.”
Jasim spread his hands in a gesture of acceptance. “I’m sure you could change my mind in five minutes, if I let you. But if we walked back down this hill and waited for the next traveler from the bulge, and the next, until the reason some of them received the grand tour and some didn’t finally became plain, there would still be another question, and another. Even if I wanted to live for ten thousand years more, I’d rather move on to something else. And in this last hour ...” He trailed off.
Leila said, “I know. You’re right.”
She sat, listening to the strange chirps and buzzes emitted by creatures she knew nothing about. She could have absorbed every recorded fact about them in an instant, but she didn’t care, she didn’t need to know.
Someone else would come after them, to understand the Aloof, or advance that great, unruly, frustrating endeavor by the next increment. She and Jasim had made a start, that was enough. What they’d done was more than she could ever have imagined, back on Najib. Now, though, was the time to stop, while they were still themselves: enlarged by the experience, but not disfigured beyond recognition.
They finished their water, drinking the last drops. They left the canteen behind. Jasim took her hand and they climbed together, struggling up the slope side by side.
GLORY
1
An ingot of metallic hydrogen gleamed in the starlight, a narrow cylinder half a meter long with a mass of about a kilogram. To the naked eye it was a dense, solid object, but its lattice of tiny nuclei immersed in an insubstantial fog of electrons was one part matter to two hundred trillion parts empty space. A short distance away was a second ingot, apparently identical to the first, but composed of antihydrogen.
A sequence of finely tuned gamma rays flooded into both cylinders. The protons that absorbed them in the first ingot spat out positrons and were transformed into neutrons, breaking their bonds to the electron cloud that glued them in place. In the second ingot, antiprotons became antineutrons.
A further sequence of pulses herded the neutrons together and forged them into clusters; the antineutrons were similarly rearranged. Both kinds of cluster were unstable, but in order to fall apart they first had to pass through a quantum state that would have strongly absorbed a component of the gamma rays constantly raining down on them. Left to themselves, the probability of them being in this state would have increased rapidly, but each time they measurably failed to absorb the gamma rays, the probability fell back to zero. The quantum Zeno effect endlessly reset the clock, holding the decay in check.
The next series of pulses began shifting the cluster
s into the space that had separated the original ingots. First neutrons, then antineutrons, were sculpted together in alternating layers. Though the clusters were ultimately unstable, while they persisted they were inert, sequestering their constituents and preventing them from annihilating their counterparts. The end point of this process of nuclear sculpting was a sliver of compressed matter and antimatter, sandwiched together into a needle one micron wide.
The gamma ray lasers shut down, the Zeno effect withdrew its prohibitions. For the time it took a beam of light to cross a neutron, the needle sat motionless in space. Then it began to burn, and it began to move.
The needle was structured like a meticulously crafted firework, and its outer layers ignited first. No external casing could have channeled this blast, but the pattern of tensions woven into the needle’s construction favored one direction for the debris to be expelled. Particles streamed backward; the needle moved forward. The shock of acceleration could not have been borne by anything built from atomic-scale matter, but the pressure bearing down on the core of the needle prolonged its life, delaying the inevitable.
Layer after layer burned itself away, blasting the dwindling remnant forward ever faster. By the time the needle had shrunk to a tenth of its original size it was moving at ninety-eight per cent of light speed; to a bystander this could scarcely have been improved upon, but from the needle’s perspective there was still room to slash its journey’s duration by orders of magnitude.
When just one thousandth of the needle remained, its time, compared to the neighboring stars, was passing five hundred times more slowly. Still the layers kept burning, the protective clusters unraveling as the pressure on them was released. The needle could only reach close enough to light speed to slow down time as much as it required if it could sacrifice a large enough proportion of its remaining mass. The core of the needle could only survive for a few trillionths of a second, while its journey would take two hundred million seconds as judged by the stars. The proportions had been carefully matched, though: out of the two kilograms of matter and antimatter that had been woven together at the launch, only a few million neutrons were needed as the final payload.
By one measure, seven years passed. For the needle, its last trillionths of a second unwound, its final layers of fuel blew away, and at the moment its core was ready to explode it reached its destination, plunging from the near-vacuum of space straight into the heart of a star.
Even here, the density of matter was insufficient to stabilize the core, yet far too high to allow it to pass unhindered. The core was torn apart. But it did not go quietly, and the shock waves it carved through the fusing plasma endured for a million kilometers: all the way through to the cooler outer layers on the opposite side of the star. These shock waves were shaped by the payload that had formed them, and though the initial pattern imprinted on them by the disintegrating cluster of neutrons was enlarged and blurred by its journey, on an atomic scale it remained sharply defined. Like a mold stamped into the seething plasma it encouraged ionized molecular fragments to slip into the troughs and furrows that matched their shape, and then brought them together to react in ways that the plasma’s random collisions would never have allowed. In effect, the shock waves formed a web of catalysts, carefully laid out in both time and space, briefly transforming a small corner of the star into a chemical factory operating on a nanometer scale.
The products of this factory sprayed out of the star, riding the last traces of the shock wave’s momentum: a few nanograms of elaborate, carbon-rich molecules, sheathed in a protective fullerene weave. Traveling at seven hundred kilometers per second, a fraction below the velocity needed to escape from the star completely, they climbed out of its gravity well, slowing as they ascended.
Four years passed, but the molecules were stable against the ravages of space. By the time they’d traveled a billion kilometers they had almost come to a halt, and they would have fallen back to die in the fires of the star that had forged them if their journey had not been timed so that the star’s third planet, a gas giant, was waiting to urge them forward. As they fell toward it, the giant’s third moon moved across their path. Eleven years after the needle’s launch, its molecular offspring rained down on to the methane snow.
The tiny heat of their impact was not enough to damage them, but it melted a microscopic puddle in the snow. Surrounded by food, the molecular seeds began to grow. Within hours, the area was teeming with nanomachines, some mining the snow and the minerals beneath it, others assembling the bounty into an intricate structure, a rectangular panel a couple of meters wide.
From across the light years, an elaborate sequence of gamma ray pulses fell upon the panel. These pulses were the needle’s true payload, the passengers for whom it had merely prepared the way, transmitted in its wake four years after its launch. The panel decoded and stored the data, and the army of nanomachines set to work again, this time following a far more elaborate blueprint. The miners were forced to look further afield to find all the elements that were needed, while the assemblers labored to reach their goal through a sequence of intermediate stages, carefully designed to protect the final product from the vagaries of the local chemistry and climate.
After three months’ work, two small fusion-powered spacecraft sat in the snow. Each one held a single occupant, waking for the first time in their freshly minted bodies, yet endowed with memories of an earlier life.
Joan switched on her communications console. Anne appeared on the screen, three short pairs of arms folded across her thorax in a posture of calm repose. They had both worn virtual bodies with the same anatomy before, but this was the first time they had become Noudah in the flesh.
“We’re here. Everything worked,” Joan marveled. The language she spoke was not her own, but the structure of her new brain and body made it second nature.
Anne said, “Now comes the hard part.”
“Yes.” Joan looked out from the spacecraft’s cockpit. In the distance, a fissured blue-gray plateau of water ice rose above the snow. Nearby, the nanomachines were busy disassembling the gamma ray receiver. When they had erased all traces of their handiwork they would wander off into the snow and catalyze their own destruction.
Joan had visited dozens of planet-bound cultures in the past, taking on different bodies and languages as necessary, but those cultures had all been plugged in to the Amalgam, the meta-civilization that spanned the galactic disk. However far from home she’d been, the means to return to familiar places had always been close at hand. The Noudah had only just mastered interplanetary flight, and they had no idea that the Amalgam existed. The closest node in the Amalgam’s network was seven light years away, and even that was out of bounds to her and Anne now: they had agreed not to risk disclosing its location to the Noudah, so any transmission they sent could only be directed to a decoy node that they’d set up more than twenty light years away.
“It will be worth it,” Joan said.
Anne’s Noudah face was immobile, but chromatophores sent a wave of violet and gold sweeping across her skin in an expression of cautious optimism. “We’ll see.” She tipped her head to the left, a gesture preceding a friendly departure.
Joan tipped her own head in response, as if she’d been doing so all her life. “Be careful, my friend,” she said.
“You too.”
Anne’s ship ascended so high on its chemical thrusters that it shrank to a speck before igniting its fusion engine and streaking away in a blaze of light. Joan felt a pang of loneliness; there was no predicting when they would be reunited.
Her ship’s software was primitive; the whole machine had been scrupulously matched to the Noudah’s level of technology. Joan knew how to fly it herself if necessary, and on a whim she switched off the autopilot and manually activated the ascent thrusters. The control panel was crowded, but having six hands helped.
2
The world the Noudah called home was the closest of the system’s five planets to their sun. The
average temperature was one hundred and twenty degrees Celsius, but the high atmospheric pressure allowed liquid water to exist across the entire surface. The chemistry and dynamics of the planet’s crust had led to a relatively flat terrain, with a patchwork of dozens of disconnected seas but no globe-spanning ocean. From space, these seas appeared as silvery mirrors, bordered by a violet and brown tarnish of vegetation.
The Noudah were already leaving their most electromagnetically promiscuous phase of communications behind, but the short-lived oasis of Amalgam-level technology on Baneth, the gas giant’s moon, had had no trouble eavesdropping on their chatter and preparing an updated cultural briefing which had been spliced into Joan’s brain.
The planet was still divided into the same eleven political units as it had been fourteen years before, the time of the last broadcasts that had reached the node before Joan’s departure. Tira and Ghahar, the two dominant nations in terms of territory, economic activity and military power, also occupied the vast majority of significant Niah archaeological sites.
Joan had expected that they’d be noticed as soon as they left Baneth – the exhaust from their fusion engines glowed like the sun – but their departure had triggered no obvious response, and now that they were coasting they’d be far harder to spot. As Anne drew closer to the home world, she sent a message to Tira’s traffic control center. Joan tuned in to the exchange.
“I come in peace from another star,” Anne said. “I seek permission to land.”
There was a delay of several seconds more than the light-speed lag, then a terse response. “Please identify yourself and state your location.”