I saw very few people on the streets who belonged to any other race than that of the invaders themselves, although there were far more females visible now, and far more civilians. The range of physical variation within the neo-Neanderthaler species was unusually small. I guessed that they were all descended from a relatively limited gene-pool; that would fit in with the popular theory that Asgard was some kind of Ark, whose many habitats had been set aside to be populated by the descendants of a favoured few individuals. Maybe all the invaders were descended from a single Adam-and-Eve pair, though they had now such a vast population that they had filled up several other habitats in addition to their allotted Eden.
Obviously, such colonization had not been a mere matter of moving into empty space—they would hardly possess armoured vehicles by the millions and an army which seemed to involve ninety-nine out of a hundred of the adult male population if they had only discovered virgin territory. What I could see in the streets didn’t give any indication of what had happened to the conquered races. The few exotic individuals I saw might conceivably have been slaves—or the enfranchised relics of populations—that had been all but wiped out.
As we cruised the city streets I amused myself with a little speculative mathematics.
Suppose, I thought, that the pale-skinned pseudo-Neanderthalers currently filled twenty cave-systems, each with a land area not much less than the land area of Mother Earth. With abundant food production they could be doubling their population every forty or fifty years. That implied that they would have to take over another sixty cave systems in the next century, and another four hundred and eighty by the end of the following century. How long would it take them to fill Asgard? How long would it take them to bump into someone who would put a stop to their game? And if Asgard were really millions of years old, why hadn’t one of its races already expanded to fill the whole macroworld?
I tried raising such issues with my captors, but the man with blond hair was sulking, and refused to talk. He had been forcibly reminded that his job was to transport me, not to enlighten me.
Below forty, things began to change again. The invaders seemed to have had every bit as much difficulty going downwards from their local area as they had going upwards. Once again, their cities were replaced by much more limited roadside developments in less promising territory. But these lower levels weren’t all dark and they weren’t all bleak. On the contrary, many were brighter, hotter, and full of life. If the topmost levels could be reckoned tundra or steppe, these were jungle, swamp, and savannah.
On one particularly long trip—at least sixty kilometres— from one downshaft to the next I sweated so much that I longed for my lost cold-suit, with its careful temperature control. We were using an armoured car here, as we did on most of the levels that were not fully civilized, and the way the hot light beat down on the metal from the thirty-metre ceiling made it feel like an oven.
The area on either side of the road had been sprayed with some kind of herbicide, and new growth was only just beginning to creep back into an area whose earlier plants were all browned and desiccated. In the distance, though, we could see trees which reached up almost to the ceiling, spreading vast palmate leaves in a horizontal array to soak up the intense radiation almost at source, so that what got through to the lower layers was a crazy zigzag of thin shafts. I couldn’t believe that the lush, strange undergrowth beneath the trees was wholly sustained by the interrupted light, although it was certainly well illuminated by it, and I concluded that much of the ground-hugging vegetation was thermosynthetic, leeching energy from the ground itself.
I’d never seen natural thermosynthetic organic systems before, and was surprised to see that they were not fungus- white, as I would have expected, but patterned and multicoloured in all kinds of bizarre ways. Like the flowering plants of Mother Earth these thermosynths had evolved in collaboration with insects, and they signalled to their pollinators in every possible way, appealing both to the visual and olfactory senses.
This was a very noisy forest, full of fluting sounds that I initially assumed to be the calling of birds, but in a rare few minutes of conversation Jacinthe Siani remarked that in this ecosystem even the plants had voices, so intense had the competition to attract insects become. Here, she said, there were also fat flightless birds that mimicked flowers both physically and musically, in order to entice their prey into their hungry beaks.
I wondered whether the invaders had located the machinery that controlled temperature in these habitats, and why they hadn’t simply turned down the thermostat to make them more hospitable. I couldn’t believe that the neo-Neanderthalers had simply decided, like good conservationists, to leave this system the way it was in order to avoid precipitating an ecocatastrophe. It seemed much more likely that they had left it the way it was because they didn’t know how to change it. They really were like a bunch of Neanderthalers on the streets of twenty-first century New York; they could pass for locals by putting on clothes, and could make a living as muggers with their own rough- hewn weapons, but they didn’t know how anything worked.
But where were the zookeepers who should have made sure that these savages couldn’t break out of their own allotted cage? Where, oh where, were the Lords of Valhalla?
As we traversed another of these tropical demi-paradises, I wondered what kind of sentients lived here. I was reluctant to conclude from the fact that I hadn’t seen a single humanoid flitting among the bushes that these systems were just gargantuan vivaria. Clearly the invaders hadn’t colonized these levels to any significant extent, but they could easily have built themselves a reputation for violence sufficient to make the locals very discreet. I fantasized about peaceful pygmies, tribes of lotus eaters, and about clever fellows who had invented musical instruments in order to charm the butterflies and the bees.
Further down, things got stranger still. I was glad to find that there wasn’t a simple temperature cline determining the distribution of levels. Had it been the case that the levels started at absolute zero and had got so hot by fifty that they could no longer sustain life, I would have become pessimistic about the prospect of finding much more of interest. But the gravity had barely begun to weaken here, and I knew that the balmy arena in which I’d fought my duel with Amara Guur was much lower down.
Below the tropical regions there were cooler ones whose life-systems seemed much less fervent. Some looked ripe for colonization, but showed even less evidence of invader penetration than the tropical hothouses—and the invaders we did see were mostly wearing masks and protective clothing. We weren’t—but we were in a vehicle that I judged to be very tightly sealed.
My companions wouldn’t tell me what it was about levels forty-three and forty-five which made them so hostile to invasion even though they looked so innocent, but the masks and suits brought to mind rumours of galactic explorers who’d found lush worlds which turned out to be biochemically booby-trapped in some way. Where many humanoid species are gathered together, travelers’ tales are a penny a hundred, and only one in a hundred has a grain of truth in it, but I’d listened to a lot of them, partly because they were fun and partly because they did at least convey some sense of the strangeness of the universe.