Donald Moffitt - Genesis 02

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.”
    “Yar,” Jao said, breathing hard. “Each thread is a single continuous molecule that reaches from here to the moon. My guess is that it’ll turn out to be mostly oxygen bonded to silica, magnesium, and aluminum, with a carbon backbone to help out with all the connections. It’d be harder than diamond and with a higher tensile strength than amorphous boron to start with, and then there’d be some kind of submolecular weaving between adjacent chains … And, oh yah, you won’t find where it’s anchored, because it reaches all the way down to the original core of this world, forty-five million miles under your feet. That’s because it’s only a guide thread—part of the warp and woof that held this world together while they were spinning it.”
    “Slow down,” Bram said. “I can believe in your tied-down moon because I can see the evidence here with my own eyes—and by the way, you’d better radio Jun Davd right away and tell him that we’ve solved the mystery of why the moons are lower than they ought to be for synchronous orbit. I’ll even accept your endless molecule till a better explanation comes along. But how could it support another forty-five million miles of its own weight?”
    “It’s the other way around,” Jao said smugly. “The idea isn’t to hold the moon down. The moon is what holds the world up.”
    Bram looked around at an apparently solid landscape. They were near one edge of the rim here. The avenues of rubble stretched to the opposite side, fifty miles away. The rectilinear mounds were higher at the lunar longitude than they had been on the outskirts of the enormous complex—the buildings had been taller and more important here. It had not occurred to Bram to wonder why the moonropes were peripheral and not centered, because, after all, the entire surface of the diskworld was the “equator.”
    “You’re getting too farfetched,” he said, and waited for the next dizzying supposition from Jao.
    “Am I?” Jao retorted. “I’ll bet you anything you care to name that when we cross that plain to the other side, we’ll find another cable car station and another set of ropes. Making an equilateral triangle with a fifty-mile base and its apex on the moon. Wait a minute! Make that a very narrow tetragon! Why not? The angle of divergence is minuscule on that scale. You might as well have parallel tethers. No, wait again! How about spreading the moon terminal still farther apart? At an angle that converges at the disk’s core? With a little truing of curves, you could have a ninety-million-mile section of parabola for your antenna. Bram, we’ve got to map the whole topography of this disk! I’ll bet it has a concave cross section. Hard to detect, but it would make this razor’s edge of a rim the widest part, except for the leftover bulge at the hub!”
    “I’d have thought that even a few inches of overhang at a height of forty-five million miles would add up to insupportable stresses.”
    “Don’t you see! ” Jao’s voice exploded in Bram’s ear. “This world was built like a suspension roof! It had to be! Otherwise, with the spin needed to keep it from collapsing under its own weight, the synchronous orbital points would have been embedded somewhere below the surface ! There wouldn’t be a stable surface! All the people and the buildings and the topsoil would be thrown off into space!”
    “What’s a suspension