“But why—”
“Come on. This way.” She had already planted a locater beacon in the debris for future reference, and now she scrambled up a low slope, sending up clouds of dust and chips that hung there in the inconsequential gravity.
“Careful of your suit,” Bram cried, but she had already disappeared over the edge. With a sigh he leaped after, soared over the peak with his legs tucked up, and dragged a toe to put himself down just on the other side. Unexpectedly, he found himself standing next to Ame on a forty-five-degree slope that ended at the base of what was ummistakably an uncovered wall of stone one hundred feet away.
“I thought I saw it when we were at the top of that last jump,” she said complacently. “Collapsed roof. Quake, maybe—we’ll have to ask Enry how quakes would work on a body with stresses like this one. Or maybe a meteorite strike. Look, it took four levels with it—it must be all tumbled down underneath there.”
She pointed, and Bram saw the broken ledges on the wall opposite, each with its cap of dust.
“And that will tell us how deep the regolith lies on a body like this one after we measure the slump,” she said. “You know, there must have been a lot of leftover junk in this system after Original Man got through with his construction project. We’ve got seventy million years’ worth of impact debris and dustfall. Lot of digging to do. Small bodies tend to lose mass because of high-energy impacts. The gravity doesn’t hold on to the stuff that fountains up. But on a body like this, even though the surface gravity is low because of rotation, there’s still the attraction of all that mass. The impact debris has no place to go, really, and over the eons it settles down in a slow rain and stays.”
“You’ve been studying your astronomy.”
She gave a pleased laugh. “It’s the same as geology in a place like this, isn’t it?”
“What do you expect to find under all that rubble?” He gestured at the tipped slope they stood on.
Her eyes shone. “Fossils, if we’re lucky. There’d be organic material if this was a food depot—or even if people lived or worked here, away from the operational center. People leave garbage. And garbage means mold, bacteria, microfossils. Maybe even the bones of vermin. Original Man must have had vermin.”
Bram remembered a childhood tale: The Dappled Piper of Shu-shih.
“Yes, indeed,” he said. “They called them rats.”
“Member of the order Rodentia” she said with a frown. “They’re in the mammal list, but Original Man doesn’t have much to say about them.”
“I’ll settle for a few dessicated bacteria. Would there be any DNA left after seventy million years?”
“Maybe. This place isn’t cold. But it’s airless and dry. Original Man ressurected something called Tyrannosaurus rex from a bone fragment after a similar period. In his twenty-first century. They kept them in zoos.”
He caught something of her excitement. “What a find a few bone fragments of Original Man would be! If we could do some DNA sequencing on a big enough sample, we could find out if he edited us before broadcasting our genetic code.”
“We don’t know his burial customs. But millions of people must have lived here over a period of time to operate the beacon. There would have been accidents … illnesses that got out of hand … the rare individual who was immune to the immortality virus—” She broke off, abruptly aware that Jao would be listening through the radio link.
“We’d better get going,” Bram said. “You’ve left a marker; we can send an excavation team later.”
But Ame was unclipping a folding shovel from her belt. She flexed the stub of a handle once to activate the memory plastic and an instant later had a proper shovel. “Let’s see how deep the regolith is where it’s slid down here,” she said. “Help me clear some of this away.”
Bram worked with his gloved hands while Ame shoveled, and within a tenth of an hour they had uncovered a smooth, hard gray surface.
“No miracle materials, those,” Ame said. “They made the walls and roof of ordinary melted and poured stone. They could afford to mold it thick enough to cover expanses like this. There was plenty of stone, and power to spare before they switched on the transmitter.”
“Twenty-three sextillion kilowatts, Jao figured,” Bram said. “Trillions of times as much energy as the entire Nar civilization had at its disposal. It’s a little disappointing to find that their building construction was so prosaic.”
“Sophisticated megaliths,” Ame said. “That’s what they are. Great slabs meant to outlast eternity. Only this one didn’t.”
She rapped the end of her shovel sharply; hydrogen atoms spilled from the reservoir they had fled to, preempted bonds again, and once more the shovel handle shrank to fit into her belt. She occupied herself for a moment chipping a rock sample from the slab. “I’ll take this back to Enry for analysis,” she said.
She bobbed to her feet a little too quickly, and Bram pulled her out of the air. “Ready?” he asked. He was anxious to return to the walker and continue toward the apparent center of the complex.
“Just a minute,” Ame said.
She looked down the rubble-strewn slope of where its edge abutted the vertical wall and studied the V-shaped trench it made. “There’s broken rock in places along the edge,” she said. “If any of them correspond to broken sections of the underside of the slab, we could get underground without digging.”
“No,” he said. “We’re not going to crawl through caves without any backup. It’s too dangerous. This place will still be here when we get back. Let’s get going. We’re wasting our air supply on the outskirts.”
“As long as we’re here, let’s just take a look,” she said.
“All right.”
He gave in and followed her down the slope. He didn’t like it. They were in a deep groove, cut off from sight of the walker and the never-ending landscape. Only the stars burned overhead.
Ame was unconcerned. She played the light of her torch along the join of the two surfaces. Color vision returned, showing Bram vitreous streaks of green, brown, and yellow mixed with the gray. Even to the naked eye it was apparent that the rubble had slid down the slope to cover any possible cracks to a depth of many feet. It would take a lot of work to clear it away.
But he was wrong. Ame’s torch played on a gaping black aperture that ran down the rocky crease in a spot that seemed remarkably free of rubble. In fact, the rubble seemed to be piled higher on either side of it.
“It goes all the way down,” she said. “About twenty feet to where the floor is. Big enough to squeeze through, and then there’s a sort of triangular tunnel made by the edge of the roof slab and the angle of the floor and wall. The tunnel’s clean—hardly any debris to clear away. I wouldn’t have expected that. The roof must have collapsed with miraculous precision. Half our work’s been done for us already. And when we explore the whole length of the cleft, we’re bound to find places where we can get through into the main part of the ruin.” Her voice rose with excitement. “Acres and acres of undisturbed …anything! Bram-tsu, why don’t we just—”
“No,” he said firmly. “We’re not going to go crawling in there now. For one thing, we’d be out of radio contact. Come on, Ame. We’ve seen everything there is to see for the moment.
“I suppose you’re right,” she sighed. She played the beam of her torch in widening spirals around the entrance. “But I don’t understand where all the rubble went.”
Then they saw the footprints.
The tracks converged on the hole from all directions. Heavy traffic. The reason they weren’t obvious in the immediate vicinity of the hole was that they became too thick there, obliterating outlines and churning up the dust. Besides, getting in and out of the hole meant belly crawling, further erasing any tracks.