Diaspora

by Greg Egan

  After the first fifty years, his Earth-self had begun to hold things back; by the time news reached Earth of the Fomalhaut clone’s demise, the messages had become pure gestalt-and-linear monologues. Paolo understood. It was only right; they’d diverged, and you didn’t send mind grafts to strangers.

  Most of the transmissions had been broadcast to all of the ships, indiscriminately. Forty-three years ago, though, his Earth-self had sent a special message to the Vega-bound clone.

  “The new lunar spectroscope we finished last year has just picked up clear signs of water on Orpheus. There should be large temperate oceans waiting for you, if the models are right. So ... good luck.” Vision showed the instrument’s domes growing out of the rock of the lunar farside; plots of the Orphean spectral data; an ensemble of planetary models. “Maybe it seems strange to you, all the trouble we’re taking to catch a glimpse of what you’re going to see in close-up, so soon. It’s hard to explain: I don’t think it’s jealousy, or even impatience. Just a need for independence.

  “There’s been a revival of the old debate: with the failure of the wormholes, should we consider redesigning our minds to encompass interstellar distances? One self spanning thousands of stars, not via cloning, but through acceptance of the natural time scale of the light-speed lag. Millennia passing between mental events. Local contingencies dealt with by non-conscious systems.” Essays, pro and con, were appended; Paolo ingested summaries. “I don’t think the idea will gain much support, though — and the new astronomical projects are something of an antidote. We can watch the stars from a distance, as ever, but we have to make peace with the fact that we’ve stayed behind.

  “I keep asking myself, though: where do we go from here? History can’t guide us. Evolution can’t guide us. The C-Z charter says understand and respect the universe . . . but in what form? On what scale? With what kind of senses, what kind of minds? We can become anything at all — and that space of possible futures dwarfs the galaxy. Can we explore it without losing our way? Fleshers used to spin fantasies about aliens arriving to ‘conquer’ Earth, to steal their ‘precious’ physical resources, to wipe them out for fear of ‘competition’... as if a species capable of making the journey wouldn’t have had the power, or the wit, or the imagination, to rid itself of obsolete biological imperatives. Conquering the galaxy is what bacteria with spaceships would do — knowing no better, having no choice.

  “Our condition is the opposite of that: we have no end of choices. That’s why we need to find another space-faring civilization. Understanding Lacerta is important, the astrophysics of survival is important, but we also need to speak to others who’ve faced the same decisions, and discovered how to live, what to become. We need to understand what it means to inhabit the universe.”

  Paolo watched the crude neutrino images of the carpets moving in staccato jerks around his dodecahedral homescape. Twenty-four ragged oblongs drifted above him, daughters of a larger ragged oblong which had just fissioned. Models suggested that shear forces from ocean currents could explain the whole process, triggered by nothing more than the parent reaching a critical size. The purely mechanical break-up of a colony — if that was what it was — might have little to do with the life cycle of the constituent organisms. It was frustrating. Paolo was accustomed to a torrent of data on anything that caught his interest; for the Diaspora’s great discovery to remain nothing more than a sequence of coarse monochrome snapshots was intolerable.

  He glanced at a schematic of the scout probes’ neutrino detectors, but there was no obvious scope for improvement. Nuclei in the detectors were excited into unstable high-energy states, then kept there by fine-tuned gamma-ray lasers picking off lower-energy eigenstates faster than they could creep into existence and attract a transition. Changes in neutrino flux of one part in ten-to-the-fifteenth could shift the energy levels far enough to disrupt the balancing act. The carpets cast a shadow so faint, though, that even this near-perfect vision could barely resolve it.

  Orlando Venetti said, “You’re awake.”

  Paolo turned. His father stood an arm’s length away, presenting as an ornately clad flesher of indeterminate age. Definitely older than Paolo, though; Orlando never ceased to play up his seniority — even if the age difference was only twenty-five percent now, and falling.

  Paolo banished the carpets from the room to the space behind one pentagonal window, and took his father’s hand. The portions of Orlando’s mind which meshed with his own expressed pleasure at Paolo’s emergence from hibernation, fondly dwelt on past shared experiences, and entertained hopes of continued harmony between father and son. Paolo’s greeting was similar, a carefully contrived “revelation” of his own emotional state. It was more of a ritual than an act of communication, but then, even with Elena he set up barriers. No one was totally honest with another person — unless the two of them intended to fuse permanently.

  Orlando nodded at the carpets. “I hope you appreciate how important they are.”

  “You know I do.” He hadn’t included that in his greeting, though. “First alien life.” C-Z humiliates the gleisner robots, at last — that was probably how his father saw it. The robots had been first to Alpha Centauri, and first to an extrasolar planet, but first life was Apollo to their Sputniks, for anyone who chose to think in those terms.

  Orlando said, “This is the hook we need, to catch the citizens of the marginal polises. The ones who haven’t quite imploded into solipsism. This will shake them up — don’t you think?”

  Paolo shrugged. Earth’s citizens were free to implode into anything they liked; it didn’t stop Carter-Zimmerman from exploring the physical universe. But even thrashing the gleisners wouldn’t be enough for Orlando; like many carnevale refugees, he had a missionary streak. He wanted every other polis to see the error of its ways, and follow C-Z to the stars.

  Paolo said, “Ashton-Laval has intelligent aliens. I wouldn’t be so sure that news of giant seaweed is going to take Earth by storm.”

  Orlando was venomous. “Ashton-Laval intervened in its so-called ‘evolutionary’ simulations so many times that they might as well have built the end products in an act of creation lasting six days. They wanted talking reptiles, and — mirabile dictu! — they got talking reptiles. There are self-modified citizens in this polis more alien than the aliens in Ashton-Laval.”

  Paolo smiled. “All right. Forget Ashton-Laval. But forget the marginal polises, too. We choose to value the physical world. That’s what defines us, but it’s as arbitrary as any other choice of values. Why can’t you accept that? It’s not the One True Path which the infidels have to be bludgeoned into following.” He knew he was arguing half for the sake of it, but Orlando always drove him into taking the opposite position.

  Orlando made a beckoning gesture, dragging the image of the carpets halfway back into the room. “You’ll vote for the microprobes?”

  “Of course.”

  “Everything depends on that, now. It’s good to start with a tantalizing glimpse, but if we don’t follow up with details soon they’ll lose interest back on Earth very rapidly.”

  “Lose interest? It’ll be fifty-four years before we know whether anyone paid the slightest attention in the first place.”

  Orlando regarded him with disappointment. “If you don’t care about the other polises, think about C-Z. This helps us, it strengthens us. We have to make the most of that.”

  Paolo was bemused. “What needs to be strengthened? You make it sound like there’s something at risk.”

  “There is. What do you think a thousand lifeless worlds would have done to us?”

  “Isn’t that entirely academic now? But all right, I agree with you: this strengthens C-Z. We’ve been lucky. I’m glad, I’m grateful. Is that what you wanted to hear?”

  Orlando said sourly, “You take too much for granted.”

  “And you care too much what I think! I’m not your ... heir.” There were times when his father seemed unable to accept that the whole
concept of offspring had lost its archaic significance. “You don’t need me to safeguard the future of Carter-Zimmerman on your behalf. Or the future of the whole Coalition. You can do it in person.”

  Orlando looked wounded — a conscious choice, but it still encoded something. Paolo felt a pang of regret, but he’d said nothing he could honestly retract.

  His father gathered up the sleeves of his gold and crimson robes — the only citizen of C-Z who could make Paolo uncomfortable to be naked — and repeated as he vanished from the room: “You take too much for granted.”

  The gang watched the launch of the microprobes together — even Liesl, though she came in mourning, as a giant dark bird. Karpal stroked her feathers nervously. Hermann appeared as a creature out of Escher, a segmented worm with six flesher-shaped feet — on legs with elbows — given to curling up into a disk and rolling along the girders of Satellite Pinatubo. Paolo and Elena kept saying the same thing simultaneously; they’d just made love.

  Hermann had moved the satellite into a notional orbit just below one of the scout probes, and changed the scape’s scale so that the probe’s lower surface, an intricate landscape of detector modules and attitude-control jets, blotted out half the sky. The atmospheric-entry capsules, ceramic teardrops three centimeters wide, burst from their launch tube and hurtled past like boulders, vanishing from sight before they’d fallen so much as ten meters closer to Orpheus. It was all scrupulously accurate, although it was part real-time imagery, part extrapolation, part faux. Paolo thought: We might as well have run a pure simulation ... and pretended to follow the capsules down. Elena gave him a guilty/admonishing look. Yeah — and then why bother actually launching them at all? Why not just simulate a plausible Orphean ocean full of plausible Orphean life-forms? Why not simulate the whole Diaspora? There was no crime of heresy in C-Z; the polis charter was just a statement of the founders’ values, not some doctrine to be accepted under threat of exile. At times it still felt like a tightrope walk, though, trying to classify every act of simulation into those which contributed to an understanding of the physical universe (good), those which were merely convenient, recreational, aesthetic (acceptable) ... and those which constituted a denial of the primacy of real phenomena (time to think about emigration).

  The vote on the microprobes had been close: seventy-two percent in favor, just over the required two-thirds majority, with five percent abstaining. Citizens created since the arrival at Vega were excluded ... not that anyone in Carter-Zimmerman would have dreamt of stacking the ballot, perish the thought. Paolo had been surprised at the narrow margin; he was yet to hear a single plausible scenario for the microprobes doing harm. He wondered if there was another, unspoken reason which had nothing to do with fears for the Orphean ecology, or hypothetical culture. A wish to prolong the pleasure of unraveling the planet’s mysteries? Paolo had some sympathy with that impulse, but the launch of the microprobes would do nothing to undermine the greater long-term pleasure of watching, and understanding, as Orphean life evolved.

  Liesl said forlornly, “Coastline erosion models show that the northwestern shore of Lambda is inundated by tsunami every ninety Orphean years, on average.” She offered the data to them; Paolo glanced at it, and it looked convincing, but the point was academic now. “We could have waited.”

  Hermann waved his eye-stalks at her. “Beaches covered in fossils, are they?”

  “No, but the conditions hardly —”

  “No excuses!” He wound his body around a girder, kicking his legs gleefully. Hermann had been scanned in the twenty-first century, before Carter-Zimmerman even existed, but over the teratau he’d wiped most of his episodic memories and rewritten his personality a dozen times. He’d once told Paolo, “I think of myself as my own great-great-grandson. Death’s not so bad, if you do it incrementally. Ditto for immortality.”

  Elena said, “I keep trying to imagine how it will feel if another C-Z clone stumbles on something infinitely better — like aliens with shortened wormholes — while we’re back here studying rafts of algae.” Her icon was more stylized than usual: sexless, hairless and smooth, the face inexpressive and androgynous.

  Paolo shrugged. “If they can shorten wormholes, they might visit us. Or share the technology, so we can link up the whole Diaspora. But I know what you mean: first alien life, and it’s likely to be about as sophisticated as seaweed. It breaks the jinx, though. Seaweed every twenty-seven light years. Nervous systems every fifty? Intelligence every hundred?” He fell silent, abruptly realizing what she was feeling: electing not to wake again after first life was beginning to seem like the wrong choice, a waste of the opportunities the Diaspora had created. Paolo offered her a mind graft expressing empathy and support, but she declined.

  She said, “I want sharp borders, right now. I want to deal with this myself.”

  “I understand.” He let the partial model of her which he’d acquired as they’d made love fade from his mind, leaving only an ordinary, guesswork-driven Elena-symbol, much like those he possessed for everyone else he knew. Paolo took the responsibilities of intimacy seriously; his lover before Elena had asked him to erase all his knowledge of her, and he’d more or less complied — the only thing he still knew about her was the fact that she’d made the request.

  Hermann announced, “Planetfall!” Paolo glanced at a replay of a scout probe view which showed the first few entry capsules breaking up above the ocean and releasing their microprobes. Nanomachines transformed the ceramic shields (and then themselves) into carbon dioxide and a few simple minerals — nothing the micrometeorites constantly raining down onto Orpheus didn’t contain — before the fragments could strike the water. The microprobes would broadcast nothing; when they’d finished gathering data, they’d float to the surface and modulate their UV reflectivity. It would be up to the scout probes to locate these specks, and read their messages, before they self-destructed as thoroughly as the entry capsules.

  Hermann said, “This calls for a celebration. I’m heading for the Heart. Who’ll join me?”

  Paolo glanced at Elena. She shook her head. “You go.”

  “Are you sure?”

  “Yes! Go on.” Her skin had taken on a mirrored sheen; her expressionless face reflected the planet below. “I’m all right. I just want some time to think things through, on my own.”

  Hermann coiled around the satellite’s frame, stretching his pale body as he went, gaining segments, gaining legs. “Come on, come on! Karpal? Liesl? Come and celebrate!”

  Elena was gone. Liesl made a derisive sound and flapped off into the distance, mocking the scape’s airlessness. Paolo and Karpal watched as Hermann grew longer and faster — and then in a blur of speed and change stretched out to wrap the entire geodesic frame. Paolo jumped away, laughing; Karpal did the same.

  Then Hermann constricted like a boa, and snapped the whole satellite apart.

  They floated for a while, two flesher-shaped creatures and a giant worm in a cloud of spinning metal fragments, an absurd collection of imaginary debris, glinting by the light of the true stars.

  * * *

  The Heart was always crowded, but it was larger than Paolo had seen it, even though Hermann had shrunk back to his original size so as not to make a scene. The huge muscular chamber arched above them, pulsating wetly in time to the music, as they searched for the perfect location to soak up the atmosphere.

  They found a good spot and made some furniture, a table and two chairs — Hermann preferred to stand — and the floor expanded to make room. Paolo looked around, shouting greetings at the people he recognized by sight, but not bothering to check for signatures. Chances were he’d met everyone here, but he didn’t want to spend the next few kilotau exchanging pleasantries with casual acquaintances.

  Hermann said, “I’ve been monitoring our modest stellar observatory’s data stream — my antidote to Vegan parochialism. Odd things are going on around Sirius. We’re seeing megaKelvin X-rays, gravity waves ... and some unexplained hot sp
ots on Sirius B.” He turned to Karpal and asked innocently, “What do you think those robots are up to? There’s a rumor that they’re planning to drag the white dwarf out of orbit, and use it as part of a giant spaceship.”

  “I never listen to rumors.” Karpal always presented as a faithful reproduction of his old gleisner body. Leaving his people and coming into C-Z must have taken considerable courage; they’d never welcome him back.

  Paolo said, “Does it matter what they do? Where they go, how they get there? There’s more than enough room for both of us. Even if they shadowed the Diaspora — even if they came to Vega — we could study the Orpheans together, couldn’t we?”

  Hermann’s cartoon insect face showed mock alarm, eyes growing wider, and wider apart. “Not if they dragged along a white dwarf! Next thing they’d want to start building a Dyson sphere.” He turned back to Karpal. “You don’t still suffer the urge, do you, for ... astrophysical engineering?”

  “Nothing C-Z’s exploitation of a few megatons of Vegan asteroid material hasn’t satisfied.”

  Paolo tried to change the subject. “Has anyone heard from Earth, lately? I’m beginning to feel unplugged.” His own most recent message was a decade older than the time lag.

  Karpal said, “You’re not missing much; all they’re talking about is Orpheus: the new lunar observations, the signs of water. They seem more excited by the mere possibility of life than we are by the certainty. And they have very high hopes.”

  Paolo laughed. “They do. My Earth-self seems to be counting on the Diaspora to find an advanced civilization with the answers to all of the Coalition’s existential problems. I don’t think he’ll get much cosmic guidance from kelp.”