“Proxima light.”
“Yes. The next step was the development of kinds of photosynthesis, creatures that could draw energy directly from that light. The new kind colonised the surface, while the older ones survived, sinking deeper into the planet. And there they still reside in great reefs, in caverns, in porous rock and aquifers, dreaming unknowable dreams. Just as on Earth, life on Per Ardua is actually dominated by the bugs in the deep layers, mass for mass. But on the surface, as photosynthesis evolved, ultimately oxygen was released as a byproduct.”
“Like the green algae on Earth.”
“Yes, Yuri Eden, this step, oxygen production, was evidently difficult to achieve; on Earth it occurred only once, and in fact came from the coupling of two older photosynthetic processes. I have yet to fully understand the equivalent process on Per Ardua—it is necessarily different because the energy content of the light here is heavy in the infrared—but it is evidently just as complex, just as unlikely to have happened.”
“Yet it did happen.”
“It did, and I have been able to date the event from traces in the Arduan genetic record: some two billion, seven hundred million years ago.” It paused. When Yuri didn’t react it went on, “The next great step in the emergence of Arduan life, again mirrored on Earth, was the development of a new kind of celclass="underline" a much more complex organism, a cell with a nucleus, a cell with different kinds of mechanisms within a containing membrane. Of course the energy available from burning up all the oxygen concentrating in the air helped with that. Such complex cells are the basis of all multicellular life, including you, including the builders. This was an information revolution, not a chemical one; these complicated creatures needed about a thousand times as much genetic information to define them as their simpler predecessors.”
“Another unlikely step.”
“Yes. But again it occurred on both worlds. And on Per Ardua this came about some two billion years ago.” Another pause. “Yuri, I am not sure you are grasping the significance of—”
“Just tell me the story,” Yuri said. He stroked his daughter’s hair, growing sleepy himself.
“Multicellular life emerged some time later—evidently another difficult step to take. Seaweeds first on Earth, like the lavers we imported to Per Ardua…”
The new camp was coming into view, the lake settling into the contours of its latest shoreline. Yuri saw builders busily working all around the lake’s edge, and smoke rising from Mardina’s camp fire.
The ColU was still talking about ancient life. “Of all the great revolutions of life this is the easiest to identify on Earth because it left such clear traces in the fossil record. On Per Ardua, of course, there is no fossil record to speak of. And yet—”
“And yet you, through heroic efforts, have worked it out anyway.”
“I’m just trying to explain, Yuri Eden.”
“All right.”
“Yes, I have seen traces of this event in the genes, and also in some fringe organisms that have survived on Per Ardua to this day. And—now this is the significant point, Yuri Eden—I have established that all this occurred some five hundred and forty-two million years ago. Do you see? Do you see?”
“See what?” Beth sat up now, rubbing her eyes. “I smelled smoke in my dreams. I thought the ColU was on fire!”
“No, honey, it’s just the camp fire.” Yuri didn’t see the ColU’s point at all, he couldn’t care less about such abstractions, and as the unit rolled into the camp the conversation was already fading from his mind. “Go find your Mom, sweetheart, and I’ll help the ColU get everything put away safely.”
Chapter 40
Mardina prepared lunch.
It was a kind of quick picnic assembled from chuno. This was a long-lasting paste you could make from potatoes by freezing, thawing, desiccating them—a smart trick from the Andes that the ColU had taught them, and invaluable for their travelling phases, but the result was a greyish muck in appearance that Beth had always cordially hated. But today she was hungry after the long journey back to the camp, and excited about the move. Certainly she didn’t want to sleep any more. They all had a peculiar mixture of tiredness and energy, Yuri thought, like they had gone on vacation maybe.
They decided to take the rest of the day off, and go exploring. The ColU, after trying to speak to Mardina about its mysterious science conclusions, grumpily rolled away and began the process of unpacking its last load from the old camp, including another tonne of terrestrial topsoil.
The family walked to the lake’s latest location, with Beth skipping ahead, and Mardina and Yuri side by side.
The ground in this country, away from the lake and the water courses, was as arid as they had ever experienced it. In fact, Yuri suspected the landscape was becoming drier, hotter, the further south they travelled. Which made sense; the further south you went and the closer to the substellar point you reached, the further Proxima rose in the sky, and the more heat it delivered. Yuri still had the map Lemmy had compiled from the colonists’ remembrances of the shuttle flight, before they’d all killed each other, and that showed concentric bands of climate and vegetation types around the substellar. If they walked far enough, Yuri supposed, they would in the end reach true lifeless desert, surrounding the substellar point itself, which the ColU predicted would be the site of a permanent storm system. Even before that, maybe there would come a point where the ground was no longer habitable for them at all. But they were following the builders, who had evidently been going through this process for uncounted millennia, and Yuri and Mardina had decided to trust them—well, having followed the jilla this far, they had no choice.
They came to the lake shore, a fringe of muddy ground with banks of new stems growing vigorously. The stems seemed to be self-seeding, but the colonists had observed the builders practising what looked like simple agriculture to help the stems along, planting shoots, irrigating the mud with crude drainage ditches. The water itself was still turbulent and turbid, not yet having settled into its new bowl. Around the shore of the lake Yuri could see builders working, setting up what looked like a nursery area with the outlines of domed shelters rising up from the debris—and already assembling basic middens, in preparation presumably for the next move of the jilla.
But there was another area where builders, adults and children, had been herded in a huddle, surrounded by others that spun and whirled around them. One by one the prisoners were taken out to an area where more builders pinned them down and, brutally, crudely, disarticulated them, taking away their constituent stems to one of the new midden heaps. It looked like a prison camp crossed with an open-air operating theatre—or, perhaps, like some appallingly brutal schoolyard game being played out by stick puppets. The sound of the continuing murders was an eerie rustling, a clatter of sticks, the scrape of sharpened stone on stem bark.
Yuri and Mardina gently guided Beth away from the scene. They had seen this many times before: it was the aftermath of a builder invasion, of conquest. There had been another community of builders here, living in the formerly dry lake bed, happily feeding off the local springs and stems—before the jilla folk arrived, brutally evicted them, flooded their homeland, and massacred any survivors.
Beth hadn’t yet worked this out. Now, luckily, she spotted the nursery and ran that way to see.
“The same every time,” Mardina said, looking back at the slaughter yard. “And I used to think the builders were cute…”
Yuri said, “They’re little wooden Nazis. Some day we’re going to have to explain all this to Beth, you know.”