Donald Moffitt - Genesis 02

to cap it. The nodules along the shaft fostered the notion.
    For a moment Bram toyed with the idea. Yggdrasil was a living spaceship, after all. Why not this? What kind of life form would look like a budding stick, and what function would be served by the gob of bubbles at one end?
    Then he dismissed the thought. The thing was a machine, after all—a relatively primitive machine that generated a howling storm of hydrogen-helium fusion and probably poisoned its inhabitants.
    “We make it at approximately twenty miles long,” Jun Davd said. “It could alight in Yggdrasil’s branches and never be noticed, but it’s still an impressive achievement for a manufactured article.”
    “What are they doing? ” Bram said.
    “Nothing, as far as we can tell. No extravehicle activity, no electromagnetic emissions. No attempt to reorient the axis of the ship as a preliminary to achieving some sort of rational orbit. They just appear to be waiting.”
    “Waiting for what?” Jao rumbled. “They sit there like that, and eventually they’re going to drift off the rim and get sucked down the side. Then they’re going to have to turn on that torch of theirs and burn some more landscape.”
    “Perhaps they don’t care,” Jun Davd said.
    Bram was staring at the glob of bubbles. Overmagnification had blended them into an undifferentiated mass, but despite the bleared focus there was enough mottled shadowing for the eye to appreciate them as a clump of hundreds of separate spherules.
    They were hollow, according to Jun Davd’s radar echoes. Empty fuel tanks, each a couple of thousand feet in diameter—big enough to hold millions of tons of frozen hydrogen in its different isotopic forms. And there would be a complex maze of piping to skim off the helium three as it became available and store that separately, too.
    Tritium was biologically hazardous. It was hard to believe that the empty bubbles had been converted into environmental pods. Jun Davd’s imagination must have run away with him. Surely no people would be that reckless with their generations.
    The vague mottling seemed to shift, showing one of the globules more distinctly.
    “Do I see movement?” Bram said. “Or is that just image shimmer?”
    Jao grabbed Bram’s arm. “No, it’s movement.”
    As they watched, one of the bubbles detached itself from the foamlike cluster and drifted free. A fine mist spouted from it.
    “Chemical jets,” Jun Davd said. “They’re matching velocity with the rim.”
    A hum of voices rose in the surrounding bay. “Hold it down,” Jao thundered.
    “You were right,” Bram told Jun Davd. “They moved into their empty fuel tanks. If that one held tritium, there must still be residual radiation. They’d have to be desperate for expansion room.”
    “The original life-support system must have been confined to the budlike structures on the stem,” Jun Davd said. “But with the fuel tanks, they’d have a hundredfold the living space in reserve, becoming available as they spilled over.”
    “What kind of intelligent race,” Bram said in dismay, “would breed that unrestrainedly, with no sureties at their destination?”
    Ame pushed through the surrounding press of bodies. “The longfoots,” she said. “The females had a dozen young to a litter, remember? They’ve come back.”
    “Or their successors have,” Bram said. “Whatever else the longfoots were, they were a thoughtful people. That ship doesn’t look like their technology.”
    “Rise and fall, Bram-tsu ,” Ame said defensively. “Devolution and reradiation of species.”
    On the screen, the separated globule fell with alarming speed toward the narrow rimscape. “That’s awfully big to be using as a lander, even on a low-gravity world,” Jun Davd said. “But that’s what they’re doing with it.”
    “One mistake and they’ll be scattered all over the landscape,” Jao grunted.
    Bram calculated spherical volume in his head. “There could be a population of thousands in that bubble. If all of the bubbles are inhabited …”
    “These strangers must like to travel in large crowds and take their environment with them,” Jun Davd said. “That detachable habitat of theirs is big enough to qualify as a self-contained colony. The ship could drop more of them off here and there around the rim and leave them to fend for themselves. Then flit around the system and seed the other disks.”
    “You talk as if that ship were a living organism.”
    Jun