The software was noncommittal about the implications, but Orlando had no doubt. Someone had transmuted these elements. Someone had deliberately weighed down this planet’s atmosphere, in order to prolong its life.
* * *
13
–
Swift
« ^ »
Carter-Zimmerman polis, Swift orbit
85 801 536 954 849 CST
16 March 4953, 15:29:12.003 UT
Yatima rode the probe beside Orlando’s, seeing both as sleek, finned cars about three delta long, hovering above Swift’s flat red desert. The real probes were spheres half a millimeter wide, powered by the light of Voltaire, largely borne up by the wind but occasionally generating lift by spinning, moving forward by pumping atmospheric gases through a network of channels coated with molecular cilia. Even with elaborate piloting software, turning the car’s steering wheel didn’t always have the desired effect. “Oasis!”
Orlando looked around. “Where?”
“On your left.” Yatima hadn’t turned yet, not wanting to sideswipe Orlando. It was unlikely that the probes themselves would touch, and it would hardly matter if they did, but one of the first things ve’d done after arriving from Konishi was hardwire a strong aversion to collisions into vis navigators. People in Carter-Zimmerman did not take kindly to other people trying to occupy the same portion of a scape.
Orlando swung his car around, and they headed for the oasis. It was a puddle of water a few meters wide — tens of kilodelta, at their current scale — trapped beneath a polymer membrane. Surface tension gently stretched the membrane into a convex mirror, reflecting an expanse of pale crimson sky that seemed to hover a few centimeters below the ground. Pure water boiled at around 60 degrees in Swift’s thin atmosphere, so rain could only fall on the night side, but when enough run-off gathered on a patch of spores the whole dessicated micro-ecology came back to life, and fought to hold on to the water for as long as possible. The membrane limited evaporation, and a mixture of other chemicals raised the boiling point by up to ten degrees, but by mid-afternoon of a 507-hour day only a fraction of the oases formed overnight remained. Still, Swift life could cope with being boiled dry at least as comfortably as most primitive Earth life could cope with being frozen.
Close up, they could see through the partially reflective surface into the dazzling world below. Broad helical carnivorous weeds shone in gold and turquoise; one swarm of mites avoiding their poisoned fronds were a deep, rich red, another were (pre-Lacerta Earth) sky blue. All Swift life made heavy use of sulfur chemistry; carbon dominated, but some primordial accident seemed to have pushed sulfur into sharing the structural role, and the intensity of the colors was one side effect.
“Maybe all of this was engineered from scratch,” Yatima mused. “For decorative purposes. Maybe Swift was sterile and airless, and someone came along and built this ecosystem, molecule by molecule. Using heavy isotopes to make it last a little longer. Like sculpting in gold, to avoid corrosion.”
“No. Wherever the Transmuters are now, this must have been their native biosphere.” Orlando seemed grimly convinced, as if the alternative was too decadent and frivolous to contemplate. “They would have substituted the isotopes slowly, feeding them into the existing atmosphere over millennia. It was a mark of respect that they didn’t wrap their home in a protective sphere, or shift its orbit, or modify its sun. They slipped in a change at the lowest possible level, underneath the biochemistry.”
Yatima guided vis car over the puddle. Vivid green eels several millimeters long undulated by, much faster than the probe. A red-and-yellow twelve-legged spider walked upside-down on the membrane, picking out the flatslugs that lived embedded in it. Yatima didn’t have much sympathy for the prey; they blithely fed on the protective polymers that almost every other species took the trouble to synthesize and excrete. Then again, it was a niche begging to be filled, and none of these creatures did anything with a conscious purpose.
“If they cared so much about their biological cousins, they can’t have been expecting Lacerta. There’s no sign of any built-in protection against a gamma ray burst.”
Orlando was unswayed. “Maybe the only things they could have done that would have made a difference were anathema to them. And they must have known that even if there were massive extinctions, they’d given the biosphere enough general resilience to recover.”
They’d found few fossils on Swift, so it was difficult to judge the extent to which life had been disrupted by the burst. Models showed that most of the existing species would have coped relatively well, but that was hardly surprising; they were the ones that had survived, not a representative sample of pre-Lacerta life. The heritable material here cycled between five different molecular coding schemes in successive generations; some species used a “pure” scheme, all Alpha leading to all Beta, Gamma, Delta, and Epsilon, while others had mixtures of all five in every generation. Some biologists claimed to have identified a genetic bottleneck due to Lacerta, but Yatima wasn’t convinced that anyone understood Swift’s biochemistry well enough yet to say what a normal level of diversity would have been.
“So where are they now? Have they been swallowed by an Introdus, or scattered by a Diaspora? If you can read their minds about everything else, that ought to be an easy question to answer.”
Orlando replied with sublime confidence, “Would I be here, if I thought I was wasting my time?” His tone was ironic, but Yatima didn’t believe he was entirely joking.
They’d scoured the planet from orbit, looking for cities, for ruins, for mass anomalies, for buried structures. But a civilization as advanced as the Transmuters could have miniaturized their polises beyond any chance of detection. One faint hope was that since they’d bothered to intervene in the fate of Swift’s organic life, they might show themselves at the oases now and then. Yatima wasn’t optimistic. If they were still on the planet they could hardly be unaware of their visitors, but they hadn’t chosen to make contact. And if they didn’t want to be seen, they were unlikely to send big, clumsy, millimeter-wide drones plowing through these puddles.
Yatima watched a rare translucent creature swim by beneath the probe, propelled by a jet of water it created by contracting its whole hollow body. Ve’d thought ve’d be prepared to study a world like this, patiently helping the biologists extract the kind of insights into evolutionary principles offered by even the most modest extraterrestrial biosphere. There were no spectacular new body plans or life cycles here, no strategies for feeding or reproduction that hadn’t been tried out back on Earth, but at a molecular level everything worked differently, and there was a vast labyrinth of utterly novel biochemical pathways to be mapped. Yet the Transmuters made it almost impossible to care. Their absence — or their perfect camouflage — monopolized everyone’s attention, transforming the intricate machinery of the biosphere into a very long footnote to a far more mesmerizing blank page.
Ve turned to Orlando. “I don’t think they’re in hiding. How shy could they be, after giving the atmosphere a spectrum that screams, ‘Civilization! Come and visit!’ We only noticed it close up, but it wouldn’t take a huge technological advance to spot it from thousands of light years away.”
Orlando didn’t reply; he’d been staring down into the puddle, and he continued to watch a swarm of crimson larvae molting, and eating each other’s discarded skins. Yatima understood the stake he had in making contact with the Transmuters. By the end of the Diaspora, when his scattered clones had reconverged, the Earth would be habitable again — but he could never feel secure about returning to the flesh until Lacerta had been explained. Any Coalition theory was likely to remain as suspect as the original belief that Lac G-1’s neutron stars would take seven million years to collide. But if the Transmuters had firsthand knowledge of the galaxy’s dynamics on a timescale of millions of years — and were beneficent enough to transform this planet’s atmosphere, atom by atom, just to save their distant relatives from extinction — sur
ely they wouldn’t begrudge an infant civilization a little information and advice on its own long-term survival.
“Okay.” Orlando looked up. “Maybe the spectrum was meant to stand out like a beacon. Maybe that’s the whole point. They could have preserved the atmosphere in a thousand other ways, but they chose a method that would get them noticed.”
“You mean they went out of their way to attract attention? Why?”
“To bring people here.”
“Then why are they being so unsociable? Or are they just waiting to ambush us?”
“Very funny.” Orlando met vis gaze. “You’re right, though: they’re not hiding from us, that’s absurd. They’re gone. But they must have left something behind. Something they wanted us to see.”
Yatima gestured at the oasis.
Orlando laughed. “You think they built this as an ornamental pond, and invited the whole galaxy to come and admire it?”
“It doesn’t look like much now,” Yatima admitted. “But even loaded with deuterium and oxygen-18 it’s been drying out slowly. Six billion years ago it might have been spectacular.”
Orlando was not persuaded. “Maybe we’re both wrong about the biosphere. Maybe there was no life here at all when the Transmuters left; it could have evolved later. The persistence of water vapor might be nothing but a side effect of the method they chose to make Swift stand out to anyone with a decent spectroscope and a glimmering of intelligence.”
“And we just haven’t searched hard enough for whatever it is we were meant to find? The lure wasn’t exactly subtle, so the payoff should be just as hard to miss. Either it’s turned to dust, or we’re looking at the dregs of it right now.”
Orlando was silent for a moment, then he said bitterly, “Then they should have used a beacon that turned to dust, too.”
Yatima resisted pointing out the technical problems with choosing isotopes with suitable half-lives. Ve said, “They might have visited other planets, and left something more enduring. The next C-Z to arrive might find some kind of artifact...” Ve trailed off, distracted. Another possibility was hovering on the edge of consciousness; ve waited a few tau, but it wouldn’t break through. Keeping vis icon in the Swift scape — along with vis linear input, in case Orlando spoke — ve shifted vis gestalt viewpoint to a map of vis own mind.
The scape portrayed a vast, three-dimensional network of interlinked neuron-like objects, but they were symbols, not junctions in the lowest-level network that dealt with individual pulses of data. Each symbol glowed with an intensity proportional to the reinforcement it was receiving from the others already dominating the network: vis conscious preoccupations. Simple linear cascades were rapidly tried out, then inhibited as stale — or vis mind would have been paralyzed by positive feedback loops of hot/cold, wet/dry banality — but novel combinations of symbols were firing all the time, and if they resonated strongly enough with the current activity, their alliance could be reinforced, and even rise to consciousness. Thought was a lot like biochemistry; there were millions of random collisions going on all the time, but it was the need to form a product with the right shape to adhere firmly to an existing template that advanced the process in a coherent way.
The map was a slow-motion replay; Yatima was looking at the firing patterns behind the nagging sensation that hadn’t quite gelled, not the real-time firing caused by the act of looking at the map. And, color-coded by the map’s software, the relevant alliance was easy to pick out, though by chance it hadn’t quite crossed the threshold into self-supporting activity. Symbols had fired for isotope, enduring, obvious ... and neutron.
Yatima was baffled for a moment, then the sense of connections falling into place welled up again, and ve knew exactly what ve hadn’t quite thought before. If the heavy, but stable, isotopes in Swift’s atmosphere were meant to attract attention to something enduring, what could be more enduring than the atoms themselves? The isotopes weren’t a message from the Transmuters saying, “Come and search this world for our libraries full of hard-won knowledge ... even though they might have turned to dust” or “Come and marvel at this life we created ... even though it might have gone extinct.”
The isotopes were saying, “Come and look at these isotopes.”
Orlando screamed, “You idiot! What are you doing?”
Yatima jumped back fully to the Swift scape. Vis car was shown half submerged in the oasis — and it was clear that either the probe itself or its gas jets had punctured the membrane. As the car ascended, the exposed water erupted into bubbles tens of delta wide, which burst into clouds of rapidly dissipated steam. Even as the surface boiled, the torn edges of the membrane sent sticky tendrils flying across the gap, and a few of these threads met and merged, crisscrossing the wound with a loose gauze to act as an anchor for repolymerization. But the hole was too large, and the rush of steam and the churning of the water shredded the tenuous scaffolding. The membrane ruptured further. The process was unstoppable now.
Orlando was standing on the seat of his car, shouting and gesticulating. “You idiot! You’ve killed them! You fucking idiot!” Yatima hesitated, then jumped Konishi-style straight into the car and seized him by the shoulders.
“It’s all right! Orlando, they’ll survive! They’re adapted for it!” He pushed ver away, flailing his arms, bellowing with grief and rage. Yatima didn’t try to touch him again, but ve kept his eyes on him, and repeated camly, “They’ll survive.” That wasn’t entirely true; only about one in three individual creatures made it through boiling and rehydration.
Ve glanced down; the whole oasis was little more than a patch of mud now, a sticky residue holding on to a few polymer-coated bubbles of steam, expanding slowly toward breaking point. All the colors of Swift life had merged into a faintly iridescent brown, without so much as an outline of any recognizable body plan. The solid geometry of the functioning organisms had been compressed into a mixture of two-dimensional proximity and chemical markers, but the process wasn’t always reversible, nor was the coding entirely unambiguous. Even members of different species caught in a dry-out together sometimes rehydrated as mutual genetic chimeras, co-opting spores from each other to serve as tissues in their reconstituted bodies.
“Where were you?” Orlando’s face radiated horror and contempt. “Those were real, living creatures — and you couldn’t even keep your eyes on them!”
“There must have been a sudden downdraft. The autopilot would have kept the probe out of the water if there’d been any way of doing that.”
“You shouldn’t have been so low to start with!”
They’d both been flying at the same altitude. Yatima said, “Look, I’m sorry it happened. The safety margin for the probes will have to be increased. But a grain of sand in the wind could have done it just as easily. And the membrane was going to burst from sheer vapor pressure in the next ten minutes anyway. You know that.”
The rage went out of Orlando’s eyes. He turned away, covering his face with his arms. Yatima waited in silence; ve’d come to realize long ago that there was nothing else ve could do.
After a while, ve said, “I think I know what the Transmuters wanted us to find.”
“I doubt it.”
“What do you add to hydrogen to make deuterium? What do you add to carbon-12 to make carbon-13?”
Orlando turned toward ver, visibly wiping away invisible tears. His public icon could mask or reveal, at will, his private sense of embodiment, but he’d never really learned to operate the two levels seamlessly — and now that his anger had subsided, he looked fragile enough to collapse and wither on the spot. It would only take one more disappointment.
Yatima said gently, “It’s been staring us in the face.”
“Neutrons?”
“Yes.”
“Neutrons are neutrons. What is there to find? What is there to travel eighty-two light years for?”
“Neutrons are wormholes.” Yatima raised vis hands and created a standard Kozuch diagram, with one end branchin
g into three. “And if Blanca’s dead clone was right, the Transmuters had all the degrees of freedom they could need to make Swift’s neutrons unique.”
* * *
14
–
Embedded
« ^ »
Carter-Zimmerman polis, Swift orbit
85 801 737 882 747 CST
18 March 4953, 23:17:59.901 UT
Yatima had arranged to meet Orlando in a scape of Lilliput Base, a twenty-meter dome full of scientific instruments located on an equatorial plateau, far from the temperate lowlands where the oases formed. The dome and everything in it had been built by conventional nanomachines, but the raw materials would have been impossible to obtain in situ without far more sophisticated technology. A former Star Puppy called Enif, who’d switched outlooks upon reaching 51 Pegasus and taken up nuclear physics with a vengeance, had succeeded in constructing the first femtomachines about a century before C-Z Voltaire’s arrival. Using the loosely-bound neutrons of halo nuclei in a manner analogous to the electron clouds of a normal atom, he’d managed to build “molecules” five orders of magnitude smaller than those with electron bonds, and then worked his way up to femtomachines able to ferry neutrons and protons to and from individual nuclei, holding the necessary increments of binding energy as deformations in their own structure. The invention had turned out to be priceless on Swift; not only were the normal, light isotopes of the five transmuted elements essential for some experiments, many other elements were rare on the planet’s surface in any form.
They’d had to wait two days for a bay to become free. Yatima entered the scape just as the previous apparatus, designed to search for traces of oxygen-16 in ancient mineral grains, was dissolving back into reservoirs of its constituent elements. Scaled at one centimeter to a delta, the meter-square bay looked big enough for any conceivable experiment, but in fact it was going to be a tight fit. Yatima had found plans for a neutron phase-shift analyzer in the library, designed by Michael Sinclair no less, a former student of Renata Kozuch. When Blanca’s proposed extensions to Kozuch Theory had reached Earth, most physicists had simply dismissed the new model as metaphysical nonsense, but Sinclair had scrutinized it carefully, hoping to devise an experimental test that would go beyond its success in explaining, after the fact, the length of the Forge’s traversable wormholes.