But they were very plain farther away.
They were longer and narrower than an ordinary human footprint, but they covered about the same area and presumably would have supported a body of similar weight. The foot that had made the imprint had been encased in a tubelike boot with a ridged underside.
When he was able to catch his breath he said, “How long ago?”
Even his untrained eye could see that the outlines of the footprints were not as sharp as the prints he and Ame had left.
Ame produced a tiny measuring stick and compared the depth of the two sets of prints. Then she poked the rod into the dust in several places.
“They’re recent,” she said.
That startled him. “How recent?”
Her features worked within the helmet. “We’ll have to assume that the dustfall on this world has been diminishing during the last seventy million years, as the disks swept out their orbit. Dimishing on a logarithmic scale, maybe. Most of the dustfall must have taken place in the first few million years. But the roof must have collapsed, too, within a few million years of the time when Original Man abandoned the place, because of the later buildup that replaced the dust that slid down into the crevice.”
“Ame—how recent?”
“It could have been within the last thirty million years.”
Bram swayed in the low gravity. “More than forty million years after we thought the human race died out,” he whispered. He grasped her space-suited arm. “Could these prints have been made by a human foot?”
She shrugged. “Depends on what you want to consider human. It took the human foot only a few million years to evolve from a grasping organ that looked something like our hands. I suppose that in another forty million years, it could have evolved into something that looked like that.”
She splashed her light around the prints. “It’s hard to tell what might have been inside that boot,” she said finally. “But the elongated proportions aside, that could be a foot with the normal configuration of heel, instep, and toes. They always bend in the same place, so they had bones. Not like a Nar footprint that varied from step to step.”
“They brought animals with them.”
The light revealed meandering chains of shallow little paw prints, hardly larger than a human thumb. Then it struck Bram.
“What kind of animal could live in vacuum?”
The paw prints divided into five slender toes. Whatever had made them had been bare to space.
Ame leaned for a closer look. “A terrestrial animal. We’ve got quite a few drawings to go on. All terrestrial vertebrates had limbs based on a plan of five digits—even those that evolved into hoofs or wings. Bram-tsu, I’ve seen pictures of paws that must have looked something like these, on little climbing creatures like tree shrews, and raccoons, and … and squirrels!”
“And rats?” he suggested. “Yes, those, too.”
“Could this world once have had air?”
“N-no. Not with the low gravity. Besides, these prints show no signs of weathering. They’re perfectly preserved.”
Bram stood up. His knees felt weak. “We’ve never seen another terrestrial animal,” he said. “On all the Nar worlds, we were the only specimen. Now it appears that we’re standing on a world that once held at least two more specimens. Let’s get going, Ame. The sooner we finish our survey, the sooner you can start digging for fossils.”
“Bram-tsu, have you noticed something?” She moved her beam of yellow light around the area, holding it low to cast shadows.
The little paw marks were always superimposed over the footprints. Never the other way around.
“The animals were later,” he said.
“A lot later,” she said. She rested the light on a nearby cluster of paw prints. “Look at these. They’re very shallow because of the low gravity and because a creature that size wouldn’t have massed very much. They can’t be more than a millimeter deep. But even so, every detail is sharp. They’re not at all blurred by dustfall. They couldn’t possibly be more than a million years old.” She traced the paw prints with the light to where they disappeared into the crevice. “They might have been made yesterday.”
It was a ladder to the moon.
Bram and Ame left the walker at the edge of the massive circular housing and walked over to where the two thick ropes rose straight up into the sky, taut as bowstrings.
The ropes were semitranslucent and so thick around that it would have taken six or seven people joining hands in a circle to have embraced them. The bulge of the winding strands was sufficient to have served as a spiral staircase.
“The moon’s tethered,” Bram said. “Like a captive balloon.”
They stared up to where the cables disappeared into the sky. They were visible, Bram guessed, to a height of a couple of miles.
One of the cars that once had plied the tremendous mooring line was stalled about a hundred yards up, like a bead on a string. It was a flattish ovoid with portholes around the rim, and the beam of torch reached high enough to show it to be painted a jolly shade of red. The cable passed through the car’s center. Bram could only guess at the nature of the mechanism that climbed the braided cord—worm gears or ratchets or cogwheels. But there must have been an inner carousel that housed it, to keep the passengers from getting dizzy.
What a ride it must have been! Being whirled upward at thousands of miles an hour. How would they have managed turnover so that they could land on the moon right side up? Was there a way station at the point where the moon’s gravitational influence took over? A transfer point linking the two cables? There would have to be one car coming down for every car going up, to maintain equilibrium: One didn’t fool around with stresses like these!
His eyes moved across a mile of circular plaza to where a second set of sky ropes had been guyed. One of them had snapped. The end of the cable lay in ruins amid the buildings it had smashed. The dangling end of the rope was visible about a half mile up. The remains of an ovoid car that had slipped off the end of the rope lay strewn across the plaza.
Bram hoped no one had been in it. The disaster most likely had happened millions of years after the departure of man—maybe even millions of years after the time of the narrow-footed visitors. But the remaining set of cables had been strong enough to hold the moon down. The astonishing system had been engineered for redundancy.
Unable to resist, Bram reached out a cautious hand and touched the glasslike rope where it rose out of an encircling collar. He might have been touching a column carved out of solid steel. It was utterly hard, utterly immovable.
“Now we know what those hairline markings on the moon are,” he said. “The moon’s wearing a harness.”
“Bram-tsu, Jao is going crazy,” Ame reminded him delicately.
“Sorry, Jao,” Bram said, switching on the receiver of his suit radio. “I guess you’ve been listening to me and Ame oohing and ahing. I forget that you can’t see it.”
A howl of the purest agony reached him. After a moment, Bram realized that words were embedded in the incoherent gargling sounds.
“Describe it. What are the dimensions? What does the surface look like? What colors do you get when you flash light on it? How’s it anchored? Careful of loose threads, if there are any. You could lose a finger.”
Bram gave him a brief description of the rope and the surrounding installation. “I can’t imagine what it would be made of,” he said. “And I can’t see how it’s anchored. It just disappears into the ground.”