Donald Moffitt - Genesis 01

reassuring solidity of the orbital facility had acted as a tonic. The Nar personnel had gone out of their way to make things comfortable for the human party during their wait for transportation—two loads of earlier arrivals had already been delivered to the higher orbit where the tree had parked itself—and the window-filling view of the Father World from the passenger lounge had been spectacular. Kerthin had ignored the splendid scenery and instead had given her nervous attention to every human drifting in and out of the lounge, as if searching for the reassurance of a familiar face. Bram or Trist had waved at several casual acquaintances, and some of them had come over to chat briefly with the foursome, but Kerthin had remained preoccupied and aloof. She had glanced up sharply once at some people returning from the rest room—Nen had seen it and reminded her that there would be no facilities on board the transfer vehicle—and later had excused herself to use Lowstation’s amenities herself. When she rejoined Bram, she seemed more relaxed, and Bram wondered if she had been sick all this time. At any rate she seemed more herself now and showed signs of looking forward to her visit to the tree.
    “Ready to fire,” the Nar attendant murmured from his central post, keeping watch with all five eyes on his ring of human charges.
    There was the gentlest of nudges, then the stars outside the plastic dome turned as the craft flipped over. A moment later there was a small steady push from the floor, and Bram felt a pound or two of weight return to him.
    There were four or five firings at intervals, then a period of coasting, while Bram wished that someone had thought to install a window in the floor. Finally the Nar attendant spoke again. “We’re less than a thousand miles from the tree now, and if you’ll keep your eye on the overhead dome, you’ll be able to see it in a minute.”
    Bram glanced at Kerthin. She was immersed in a printout of Shaw’s Saint Joan, which she had brought along for the ride. She appeared not to notice the tiny jolt when the attitude jets began to roll the vehicle over on its back again. Bram got her attention with a nudge of his elbow, and she put the printout down and looked up.
    The great living starship that was the tree swam majestically into view through the overhead bubble and came to a halt as the transfer craft steadied itself.
    Bram gaped unabashedly. Beside him, he heard Kerthin catch her breath.
    The star-traveling organism resembled not at all any tree ever seen on land or even the giant trees grown in space stations. Vacuum-poplars spread outward, not upward.
    Its form was that of two umbrella-shaped masses held apart by a trunk that was relatively too short to be seen between them at this shallow angle of approach. The trunk would, Bram knew, be some eighty miles long and twenty or more miles thick. But it was dwarfed by the twin wheels of growth that it had given rise to after it had done its essential work.
    The immense silvery crown of leaves, some three hundred miles in diameter, was a flattened dome—almost a disk—whose irregularities were canceled by distance to make it as round and symmetrical as any artificial object.
    The foliated root system at the other end of the hidden stem was an almost exact match in size and shape to the crown. A living system like a vacuum-poplar had exquisite feedback. It had to. Spinning at one gravity at its twin rims—slowing its spin as it grew outward in order to maintain a constant one-g level—it had regulated its growth over the centuries for balance and symmetry.
    It was hard to detect the spin at the tree’s present enormous diameter, but spin it must, Bram knew, unless it wanted to lose its shape. A space poplar started life as a seedling on one of the billions of snowballs in the cometary halo at the outskirts of the system, feeding on water ice and the inevitable carbon and nitrogen compounds. When it had used up its comet—rarely more than a few miles in diameter—it was still a fairly orthodox looking tree, with leaves at one end and roots at the other. Long shapes tumble in space, and the random rotation encouraged the tree to continue to grow straight—much like the trees grown in space stations—except that centrifugal force pulled it in both directions. The roots foliated, modified themselves to take advantage of random traces of water and organic molecules floating around in the shell of unborn comets. The