Read Online Building Harlequin’s Moon by Larry Niven, Brenda Cooper - Free Book Online Page A

we get more plant cover. That’s the beauty of a self-regulating system; we both watch for change and cause change. Terraforming is one long search for balance. We can tweak the system—generate wind if we need it over the lake, affect the surface temperature—there’s a soletta in geostationary orbit—”
    Harry interrupted. “Soletta?”
    “The soletta is a bank of mirrors that focuses light from Apollo onto Selene, increasing the insolation—the light level from Apollo. We can turn mirrors on or off to affect insolation and tweak the temperature and energy supply. It’s working so well it’s been virtually automatic longer than you’ve been alive.”
    “Which isn’t very long,” Ali said dryly. “And it was a fight. Gabriel has had to rebuild the touchy thing twice so far. Once a single asteroid from a swarm got past our defenses and smashed the mirrors to shards. There wasn’t much atmosphere yet, so some of them made it to the surface. Wear shoes!”
    Gabriel laughed. “You’d have to dig pretty far to find any remains of that glass.”
    Ali went on, unfazed. “Oh, and the second time, it just disappeared. Just flat disappeared. We were all cold, one of our long down times. Astronaut woke me up to say there was nothing there. Astronaut didn’t see it happen: Selene was between
John Glenn
and the soletta when it disappeared. The soletta might be the single most fragile part of our whole system. But without it, we couldn’t regulate temperature, and Selene would get too cold to live on.”
    “Did you help him rebuild it?” Ursula asked Ali.
    “I was cold. Erika did that.”
    “I haven’t met Erika,” Rachel observed. “Where is she?”
    “Cold,” Gabriel muttered.
    Rachel turned her eyes on Gabriel, and he saw pain flash across them. “Like Mom?” she asked.
    Ali’s answer was sharp. “We don’t know about your mom. Be patient.”
    Rachel’s jaws clenched. She looked down into the crater as if she could see the bottom.
    They brought out water bottles and lapsed into uncomfortable silence. Harlequin was almost straight above them now. “Can you see the water rising?” Gabriel asked.

    “At the edges?” Rachel replied.
    “The whole sea will be affected. A tide is a response to gravity—all of Selene feels the pull of Harlequin; the elasticity of water illustrates it.”
    Water crept up the sides of the great bowl below them. Rocks were slowly dampened by wind spray, and then submerged in rising waves.
    Gabriel had seen this hundreds of times. He watched the children. He wanted them awed. Rachel and Harry stood side by side, both rapt and fully attentive. Ursula was on Rachel’s far side, farther back, still sitting, craning her neck to see into the crater without being near the edge.
    Gabriel leaned back, looking up at the gas giant overhead. The ring, of course, was edge on to him, bisecting the planet. A huge storm tracked slowly across the surface, the fractal edges of its motion lulling him into a near trance state. Ali’s voice was backdrop; talk about tidal pulls and bulges. He heard her explain that most moons were tidally locked, that Selene’s core had been once, and Selene would be again. Finally, he heard Rachel point out that the water level was falling. He took a deep breath and stood up, strapping on his wings.
    They all stood at the edge, backs to the sea, and looked down over the long slope of the outside crater rim between silver threads of waterfall. White and red rock filled with pillows of pumice crunched under their feet. Below them was rocky ledge after rocky ledge; then, starting nearly a third of the way down, a gentle slope turning greener as it flowed into checkered fields.
    One by one they ran and leaped up, snapping wings open in time to start the long flight down to Clarke Base. The children rose high in the thermals, almost immediately, circling and swooping and chasing each other. Gabriel finessed his glide, letting his mind go completely into the