Transvergence by Charles Sheffield Page B

lot of unexplored territory. If you wanted to disappear, and remain hidden, that's the first place in the spiral arm that you'd pick."

    She stared around at five silent and expressionless faces. "Any comment?"

    "Go on," Rebka said. "No quarrels so far. Where do you go from here?"

    "I know the locations of all the Builder artifacts. Three hundred and seventy-seven of them lie within the Zardalu Communion territory. A hundred and forty-nine of those lie in fairly remote territory, where a Zardalu appearance might not be spotted at once. More than that, if you go along with my assumption that the Zardalu had to land someplace close to one of those artifacts, then I can narrow the field a lot further. You see, for many artifacts there's just no planet within many light-years where an air-breathing life-form can survive. Throw in that requirement, and you have my final list."

    She turned to the console and touched three keys. "And here it is, along with my calculations."

    "Sixty-one planets, around thirty-three different stars." Louis Nenda was frowning. "I can rule out a couple of those—I know 'em. Don't forget Kallik and me are from the Communion. But it's still too many. Hold on a minute, while I pass your list to At."

    The others waited impatiently during the transfer. Nenda was still in silent dialogue with the Cecropian when Julian Graves and J'merlia arrived in the control room. Rebka gestured to Darya's list, still on the screen. "Candidate places we might find Zardalu. Too many."

    "And while I have no wish to complicate matters"—Kallik was busy at the console—"here are the results of my analysis, quite independently evolved although with a similar guiding logic."

    Another substantial list was appearing on the screen, next to Darya's. "Seventy-two planets," Kallik said apologetically, "around forty-one different stars. And only twenty-three planets in common with Professor Lang."

    "And it's getting worse," Nenda said. "Atvar H'sial did her own analysis, with a logic similar to Darya's. But she didn't prepare it for visual output. She's doing that now."

    The Cecropian was back at her console. Within a few seconds, a third long list and a series of equations began to appear on the displays. Julian Graves groaned as it went on and on. "Worse and worse."

    "Eighty-four planets," E.C. Tally said. "Around forty-five stars." The embodied computer's internal processing unit, with a clock rate of eighteen attoseconds, could query the ship's data bank through the attached neural cable and perform a full statistical analysis while the humans were still trying to read the list. "Twenty-nine planets," he went on, "in common with Professor Lang, thirty in common with Kallik, and eleven planets common to all three. There is a sixty-two percent probability that the planet sought is one of the eleven, and a fifteen percent chance that it is not any one of the one hundred and forty-six in the combined list."

    "Which says you got too many places, and lousy odds." Nenda turned to Hans Rebka. "So I guess it's our turn in the barrel. You want to tell it? People tend to get sort of excited when I say things."

    Rebka shrugged. He moved to sit closer to Darya. "Nenda and I did our own talking when we were in the engine room. What you three did was interesting, a nice, abstract analysis; but we think you're missing a basic point.

    "You said, hey, nobody reported Zardalu in the Fourth Alliance or the Cecropia Federation or the Phemus Circle, so that means they can't be there. But you know the Zardalu as well as we do. Don't you think it's more likely that they didn't get reported because there was nobody left to report them? If you want to find Zardalu, you look for evidence of violence . Better yet, you look for evidence of disappearances somewhere close to a Builder artifact. If the Zardalu arrived in the spiral arm and took a ship to get them back to their home planet, they'd have made sure there were no survivors to talk about