by Greg Egan
In fact, most of the travelers had come just a few hundred light years to be here. She and Jasim had chosen to keep their role in the history of Eavesdropping out of their précis, and Leila caught herself with a rather smug sense of walking among the crowd like some unacknowledged sage, bemused by the late-blooming, and no doubt superficial, interest of the masses. On reflection, though, any sense of superior knowledge was hard to justify, when most of these people would have grown up steeped in developments that she was only belatedly catching up with. A new generation of observatories had been designed while she and Jasim were in transit, based on “strong bullets”: specially designed femtomachines, clusters of protons and neutrons stable only for trillionths of a second, launched at ultra-relativistic speeds so great that time dilation enabled them to survive long enough to collide with other components and merge into tiny, short-lived gamma-ray observatories. The basic trick that had built Trident had gone from a one-off gamble into a miniaturized, mass-produced phenomenon, with literally billions of strong bullets being fired continuously from thousands of planets around the inner disk.
Femtomachines themselves were old hat, but it had taken the technical challenges of Eavesdropping to motivate someone into squeezing a few more tricks out of them. Historians had always understood that in the long run, technological progress was a horizontal asymptote: once people had more or less everything they wanted that was physically possible, every incremental change would take exponentially longer to achieve, with diminishing returns and ever less reason to bother. The Amalgam would probably spend an eon inching its way closer to the flatline, but this was proof that shifts of circumstance alone could still trigger a modest renaissance or two, without the need for any radical scientific discovery or even a genuinely new technology.
They stopped to rest in a square, beside a small fountain gushing aromatic hydrocarbons. The Tassef locals, quadrupeds with slick, rubbery hides, played in the sticky black spray then licked each other clean.
Jasim shaded his eyes from the sun. He said, “We’ve had our autumn child, and we’ve seen its grandchildren prosper. I’m not sure what’s left.”
“No.” Leila was in no rush to die, but they’d sampled fifty thousand years of their discovery’s consequences. They’d followed in the wake of the news of the gamma ray signals as it circled the inner disk, spending less than a century conscious as they sped from world to world. At first they’d been hunting for some vital new role to play, but they’d slowly come to accept that the avalanche they’d triggered had out-raced them. Physical and logical maps of the Aloof’s network were being constructed, as fast as the laws of physics allowed. Billions of people on thousands of planets, scattered around the inner rim of the Amalgam’s territory, were sharing their observations to help piece together the living skeleton of their elusive neighbors. When that project was complete it would not be the end of anything, but it could mark the start of a long hiatus. The encrypted, classical data would never yield anything more than traffic routes; no amount of ingenuity could extract its content. The quantum keys that could unlock it, assuming the Aloof even used such things, would be absolutely immune to theft, duplication, or surreptitious sampling. One day, there would be another breakthrough, and everything would change again, but did they want to wait a hundred thousand years, a million, just to see what came next?
The solicitous heptapods – not locals, but visitors from a world thirty light years away who had nonetheless taken on some kind of innate duty of hospitality – seemed to show up whenever anyone was hungry. Leila tried to draw this second one into conversation, but it politely excused itself to rush off and feed someone else.
Leila said, “Maybe this is it. We’ll wait for the news from Massa, then celebrate for a while, then finish it.”
Jasim took her hand. “That feels right to me. I’m not certain, but I don’t think I’ll ever be.”
“Are you tired?” she said. “Bored?”
“Not at all,” he replied. “I feel satisfied. With what we’ve done, what we’ve seen. And I don’t want to dilute that. I don’t want to hang around forever, watching it fade, until we start to feel the way we did on Najib all over again.”
“No.”
They sat in the square until dusk, and watched the stars of the bulge come out. They’d seen this dazzling jeweled hub from every possible angle now, but Leila never grew tired of the sight.
Jasim gave an amused, exasperated sigh. “That beautiful, maddening, unreachable place. I think the whole Amalgam will be dead and gone without anyone setting foot inside it.”
Leila felt a sudden surge of irritation, which deepened into a sense of revulsion. “It’s a place, like any other place! Stars, gas, dust, planets. It’s not some metaphysical realm. It’s not even far away. Our own home world is twenty times more distant.”
“Our own home world doesn’t have an impregnable fence around it. If we really wanted to, we could go back there.”
Leila was defiant. “If we really wanted to, we could enter the bulge.”
Jasim laughed. “Have you read something in those messages that you didn’t tell me about? How to say ‘open sesame’ to the gatekeepers?”
Leila stood, and summoned a map of the Aloof’s network to superimpose across their vision, criss-crossing the sky with slender cones of violet light. One cone appeared head-on, as a tiny circle: the beam whose spillage came close to Tassef. She put her hand on Jasim’s shoulder, and zoomed in on that circle. It opened up before them like a beckoning tunnel.
She said, “We know where this beam is coming from. We don’t know for certain that the traffic between these particular nodes runs in both directions, but we’ve found plenty of examples where it does. If we aim a signal from here, back along the path of the spillage, and we make it wide enough, then we won’t just hit the sending node. We’ll hit the receiver as well.”
Jasim was silent.
“We know the data format,” she continued. “We know the routing information. We can address the data packets to a node on the other side of the bulge, one where the spillage comes out at Massa.”
Jasim said, “What makes you think they’ll accept the packets?”
“There’s nothing in the format we don’t understand, nothing we can’t write for ourselves.”
“Nothing in the unencrypted part. If there’s an authorization, even a checksum, in the encrypted part, then any packet without that will be tossed away as noise.”
“That’s true,” she conceded.
“Do you really want to do this?” he said. Her hand was still on his shoulder, she could feel his body growing tense.
“Absolutely.”
“We mail ourselves from here to Massa, as unencrypted, classical data that anyone can read, anyone can copy, anyone can alter or corrupt?”
“A moment ago you said they’d throw us away as noise.”
“That’s the least of our worries.”
“Maybe.”
Jasim shuddered, his body almost convulsing. He let out a string of obscenities, then made a choking sound. “What’s wrong with you? Is this some kind of test? If I call your bluff, will you admit that you’re joking?”
Leila shook her head. “And no, it’s not revenge for what you did on the way to Trident. This is our chance. This is what we were waiting to do – not the Eavesdropping, that’s nothing! The bulge is right here in front of us. The Aloof are in there, somewhere. We can’t force them to engage with us, but we can get closer to them than anyone has ever been before.”
“If we go in this way, they could do anything to us.”
“They’re not barbarians. They haven’t made war on us. Even the engineering spores come back unharmed.”
“If we infest their network, that’s worse than an engineering spore.”
“‘Infest’! None of these routes are crowded. A few exabytes passing through is nothing.”
“You have no idea how they’ll react.”
“No,” she confessed. �
��I don’t. But I’m ready to find out.”
Jasim stood. “We could send a test message first. Then go to Massa and see if it arrived safely.”
“We could do that,” Leila conceded. “That would be a sensible plan.”
“So you agree?” Jasim gave her a wary, frozen smile. “We’ll send a test message. Send an encyclopedia. Send greetings in some universal language.”
“Fine. We’ll send all of those things first. But I’m not waiting more than one day after that. I’m not going to Massa the long way. I’m taking the short-cut, I’m going through the bulge.”
8
The Amalgam had been so generous to Leila, and local interest in the Aloof so intense, that she had almost forgotten that she was not, in fact, entitled to a limitless and unconditional flow of resources, to be employed to any end that involved her obsession.
When she asked Tassef for the means to build a high-powered gamma-ray transmitter to aim into the bulge, it interrogated her for an hour, then replied that the matter would require a prolonged and extensive consultation. It was, she realized, no use protesting that compared to hosting a billion guests for a couple of centuries, the cost of this was nothing. The sticking point was not the energy use, or any other equally microscopic consequence for the comfort and amenity of the Tassef locals. The issue was whether her proposed actions might be seen as unwelcome and offensive by the Aloof, and whether that affront might in turn provoke some kind of retribution.
Countless probes and spores had been gently and patiently returned from the bulge unharmed, but they’d come blundering in at less than lightspeed. A flash of gamma rays could not be intercepted and returned before it struck its chosen target. Though it seemed to Leila that it would be a trivial matter for the network to choose to reject the data, it was not unreasonable to suppose that the Aloof’s sensibilities might differ on this point from her own.
Jasim had left Shalouf for a city on the other side of the planet. Leila’s feelings about this were mixed; it was always painful when they separated, but the reminder that they were not irrevocably welded together also brought an undeniable sense of space and freedom. She loved him beyond measure, but that was not the final word on every question. She was not certain that she would not relent in the end, and die quietly beside him when the news came through from Massa; there were moments when it seemed utterly perverse, masochistic and self-aggrandizing to flee from that calm, dignified end for the sake of trying to cap their modest revolution with a new and spectacularly dangerous folly. Nor though, was she certain that Jasim would not change his own mind, and take her hand while they plunged off this cliff together.
When the months dragged on with no decision on her request, no news from Massa and no overtures from her husband, Leila became an orator, traveling from city to city promoting her scheme to blaze a trail through the heart of the bulge. Her words and image were conveyed into virtual fora, but her physical presence was a way to draw attention to her cause, and Listening Party pilgrims and Tassefi alike packed the meeting places when she came. She mastered the locals’ language and style, but left it inflected with some suitably alien mannerisms. The fact that a rumor had arisen that she was one of the First Eavesdroppers did no harm to her attendance figures.
When she reached the city of Jasim’s self-imposed exile, she searched the audience for him in vain. As she walked out into the night a sense of panic gripped her. She felt no fear for herself, but the thought of him dying here alone was unbearable.
She sat in the street, weeping. How had it come to this? They had been prepared for a glorious failure, prepared to be broken by the Aloof’s unyielding silence, and instead the fruits of their labor had swept through the disk, reinvigorating a thousand cultures. How could the taste of success be so bitter?
Leila imagined calling out to Jasim, finding him, holding him again, repairing their wounds.
A splinter of steel remained inside her, though. She looked up into the blazing sky. The Aloof were there, waiting, daring her to stand before them. To come this far, then step back from the edge for the comfort of a familiar embrace, would diminish her. She would not retreat.
#
The news arrived from Massa: forty thousand years before, the spillage from the far side of the bulge had been caught in time. Vast swathes of the data matched the observations that Tassef had been holding in anticipation of this moment, for the last fifteen thousand years.
There was more: reports of other correlations from other observatories followed within minutes. As the message from Massa had been relayed around the inner disk, a cascade of similar matches with other stores of data had been found.
By seeing where packets dropped out of the stream, their abstract addresses became concrete, physical locations within the bulge. As Leila stood in Shalouf’s main square in the dusk, absorbing the reports, the Aloof’s network was growing more solid, less ethereal, by the minute.
The streets around her were erupting with signs of elation: polyglot shouts, chirps and buzzes, celebratory scents and vivid pigmentation changes. Bursts of luminescence spread across the square. Even the relentlessly sober heptapods had abandoned their food carts to lie on their backs, spinning with delight. Leila wheeled around, drinking it in, commanding her translator to punch the meaning of every disparate gesture and sound deep into her brain, unifying the kaleidoscope into a single emotional charge.
As the stars of the bulge came out, Tassef offered an overlay for everyone to share, with the newly mapped routes shining like golden highways. From all around her, Leila picked up the signals of those who were joining the view: people of every civilization, every species, every replicator were seeing the Aloof’s secret roads painted across the sky.
Leila walked through the streets of Shalouf, feeling Jasim’s absence sharply, but too familiar with that pain to be overcome by it. If the joy of this moment was muted, every celebration would be blighted in the same way, now. She could not expect anything else. She would grow inured to it.
Tassef spoke to her.
“The citizens have reached a decision. They will grant your request.”
“I’m grateful.”
“There is a condition. The transmitter must be built at least twenty light-years away, either in interstellar space, or in the circumstellar region of an uninhabited system.”
“I understand.” This way, in the event that the Aloof felt threatened to the point of provoking destructive retribution, Tassef would survive an act of violence, at least on a stellar scale, directed against the transmitter itself.
“We advise you to prepare your final plans for the hardware, and submit them when you’re sure they will fulfill your purpose.”
“Of course.”
Leila went back to her room, and reviewed the plans she had already drafted. She had anticipated the Tassefi wanting a considerable safety margin, so she had worked out the energy budgets for detailed scenarios involving engineering spores and forty-seven different cometary clouds that fell within Tassef’s jurisdiction. It took just seconds to identify the best one that met the required conditions, and she lodged it without hesitation.
Out on the streets, the Listening Party continued. For the billion pilgrims, this was enough: they would go home, return to their grandchildren, and die happy in the knowledge that they had finally seen something new in the world. Leila envied them; there’d been a time when that would have been enough for her, too.
She left her room and rejoined the celebration, talking, laughing, dancing with strangers, letting herself grow giddy with the moment. When the sun came up, she made her way home, stepping lightly over the sleeping bodies that filled the street.
#
The engineering spores were the latest generation: strong bullets launched at close to lightspeed that shed their momentum by diving through the heart of a star, and then rebuilding themselves at atomic density as they decayed in the stellar atmosphere. In effect, the dying femtomachines constructed nanomachines bearing t
he same blueprints as they’d carried within themselves at nuclear densities, and which then continued out to the cometary cloud to replicate and commence the real work of mining raw materials and building the gamma ray transmitter.
Leila contemplated following in their wake, sending herself as a signal to be picked up by the as-yet-unbuilt transmitter. It would not have been as big a gamble as Jasim’s with Trident; the strong bullets had already been used successfully this way in hundreds of similar stars.
In the end, she chose to wait on Tassef for a signal that the transmitter had been successfully constructed, and had tested, aligned and calibrated itself. If she was going to march blindly into the bulge, it would be absurd to stumble and fall prematurely, before she even reached the precipice.
When the day came, some ten thousand people gathered in the center of Shalouf to bid the traveler a safe journey. Leila would have preferred to slip away quietly, but after all her lobbying she had surrendered her privacy, and the Tassefi seemed to feel that she owed them this last splash of color and ceremony.
Forty-six years after the Listening Party, most of the pilgrims had returned to their homes, but of the few hundred who had lingered in Shalouf nearly all had showed up for this curious footnote to the main event. Leila wasn’t sure that anyone here believed the Aloof’s network would do more than bounce her straight back into the disk, but the affection these well-wishers expressed seemed genuine. Someone had even gone to the trouble of digging up a phrase in the oldest known surviving language of her ancestral species: safar bekheyr, may your journey be blessed. They had written it across the sky in an ancient script that she’d last seen eighty thousand years before, and it had been spread among the crowd phonetically so that everyone she met could offer her this hopeful farewell as she passed.
