Cold as Ice

by Charles Sheffield

  This was the point where Magrit Knudsen or anyone else on her staff would probably have given up. Bat was just starting. Many of his Great War investigations had begun with much less than this.

  The Ceres Museum was the central repository of all wartime Belt data. It should possess a full backup of files from Mandrake, or show where the original Mandrake duplicates were now maintained.

  Bat initiated a call sequence to Ceres, then changed his mind. The Ganymede-Ceres communication geometry was bad, and would be bad for the next year because of orbital configuration. He would have to wait almost an hour for a reply. Maybe he could do it locally. Ganymede ought to have at least summary files of the same information.

  He set up his linkages. And found, within minutes, that they led nowhere. The Ganymede file showed that all backup data for Mandrake had been stored on Pallas. But the Pallas inventory file revealed in turn that all of those backup records had themselves been purged near the end of the war.

  Purged, for undocumented reasons.

  Dead end.

  Bat grunted. He had reached the point where Magrit definitely would have said, "The hell with it," and abandoned the chase. But Bat had a long way to go before he would admit defeat.

  He returned to ponder one of his data elements: The Pelagic had been out of fuel before the survival pods were launched. The pods would therefore have been ejected ballistically, which in turn meant a low-velocity escape from the ship. A pure ballistic launch, without drive, made sense for other reasons. The Seeker would surely have destroyed any powered craft leaving the Pelagic.

  But a ballistic launch, with its low relative velocity, had other implications. The nine survival pods at the time of their launch must have shared, to a close approximation, the velocity components of the Pelagic itself. And the parent vessel's inertial position and speed had been monitored by the flight recorder until the ship's moment of final destruction.

  Suppose that the survival pods had not been destroyed? Then they would have continued from their time of release as free-orbiting bodies, moving under the gravitational influence of the major bodies of the solar system. It would be an elementary but computer-intensive task to propagate the spreading locus of those free-fall trajectories forward through time. At any given moment, the possible positions and velocities of the survival pods would occupy a region of phase space, large in everyday terms, but minute compared with the set of all speeds and positions possible for bodies moving within the solar system.

  Bat called up the necessary programs and fed in the initial orbital elements from the flight recorder. He asked for an estimated computation time, and grimaced at the result. He could not expect an answer for hours.

  There was one other useful thing to do while he waited. Although the Pallas backup records for events on Mandrake had been purged at the end of the war, the decision to make that purge, and its implementation, would not have been made by machine. It must have involved human action. One or more of those humans might still be alive, and able to tell why a data purge had been ordered.

  The big problem was in tracking down the people. Wartime personnel records for the Belt were also stored on Ceres. And for them, no summary file existed on Ganymede. Bat would have to go to the source, which meant that he was back to the inevitable hour-long communication delays between the Belt and the Jovian system. He carefully constructed his inquiry, seeking to make it so self-contained that time would not be wasted with return queries from the Belt's retrieval systems.

  It took longer than he expected, but it never occurred to Bat to quit. He was enjoying himself. When he heard the sound of the door of Bat Cave sliding open, his only feeling was one of irritation at an uncalled-for disturbance.

  He turned, expecting Magrit Knudsen. For the past eight years she had been the only person to visit him without an appointment.

  It was not Magrit. A man stood on the threshold, scanning the room as though he had no idea that he was intruding.

  Bat scowled at him. "Although your face is not unfamiliar to me, I must point out that these are private quarters. Your presence is uninvited. I ask you to leave. At once."

  Cyrus Mobarak nodded affably. "Since you know me, and I obviously know you, introductions do not seem to be called for."

  "They are as uncalled-for as your presence. Leave, if you please. Immediately."

  "Suppose that Cyrus Mobarak agrees to go—but Torquemada asks if he may remain."

  Bat froze. "You purport to be Torquemada?"

  "I am Torquemada."

  "Prove it."

  "I can cite twenty years of Super-Puzzle rivalry between Torquemada and Megachirops."

  "Meaningless. Anyone could research the leading problem setters and solvers of the Puzzle Network."

  "Then how about this: There are fourteen published solutions of Grew's Labyrinth."

  "That is no better. I know them all. So do a score of others."

  "And if I could show you a fifteenth form, published nowhere?"

  That produced a pause.

  "Do so . . . if you can." Bat pushed a pad across to Cyrus Mobarak.

  "I can, but not on something so small." Mobarak nodded to the wall-size display screen. "Can that be annotated at full resolution?"

  "At any preferred scale."

  "Do you have the published solutions of Grew's Labyrinth available in storage?"

  Rather than answering, Bat bent over his keyboard. After thirty seconds, the display filled with fourteen distinct curvilinear patterns, each one tangled and reentrant. "The known forms."

  "Very good. If I might move them around a little . . ."

  Bat held out the keyboard. Mobarak took it and was busy for a minute or so, rearranging the position of each figure on the great screen.

  "The fourteen," he said. He raised a bushy eyebrow at Bat, who nodded. "And now . . ."

  Mobarak drew in seventeen complexly curved lines, running among and joining the fourteen separate figures. "Behold, a fifteenth."

  "Ahhh." Bat stared for only a few seconds before he sighed out a long, admiring breath. "A super labyrinth. It contains as subunits all the known forms. Most satisfying. How did you find it?"

  Mobarak laughed. Bat's question was an inside joke of the Super-Puzzle Network, the cliché question that all non-puzzlers asked: "How do you come up with those weird solutions?"

  "This time I can actually give you an answer," Mobarak said. "There's an analogous situation in the theory of finite groups—a monster group that contains many smaller ones as subgroups."

  "And at a less elevated plane of inquiry, how did you find me?"

  "With Megachiroptera as the formal name of the suborder of great bats, Megachirops is a poor choice of identifier for any bat who really seeks to remain hidden."

  "Ah." Bat shrugged. "An admitted folly on my part. Such conceits had their appeal to the mind of a fourteen-year-old, but you are right. I should have changed my code name." He gestured to a chair at the other side of the room. "Although I am honored to meet Torquemada, I must admit that I would have preferred you at a distance, as an esteemed rival on the network."

  "I understand." Mobarak sat down far away, respecting Bat's need for personal space. "I came here only because I have a problem. One that I cannot discuss over public channels, and one that I don't know how to solve."

  "If it defeats Torquemada, why am I likely to do better?"

  "Because you have information that I lack about activities in the Jovian system." Cyrus Mobarak leaned back in his seat. He had difficulty in keeping his manner casual, but he sensed that his usual style of intense personal interaction would be a disaster with Rustum Battachariya. "You and I have never met, but I assume that you have heard of me through standard channels. That is not vanity on my part. I am a public figure."

  "I know of you . . . or at least I know such parts of the public figure as you choose to make public." Battachariya was sitting perfectly still, his close-cropped head as black, round, and expressionless as a cannonbal
l.

  "Then you will not be surprised to learn that although I have done my best to make friends around the system, I have by my actions also made enemies. Not because I sought to, but because my inventions have blighted the hopes and plans of others."

  "The universe does not guarantee equality, either in talent or in opportunities. You must have a great deal of experience in dealing with such adversaries. Far more experience than I."

  "I do indeed. If I know who they are. But in this case, I do not know. I have a secret enemy, someone who lives in the Jovian system. I can detect the effects of that animosity, but I am unable to trace its source. But you, with your access to Jovian records, and your skill as a puzzle-solver . . ."

  "Spare my blushes." Bat looked as incapable of facial erythema as an obsidian statue. "I assume that you are willing to provide me with the clues that you mention?"

  "That is why I am here. But it will take a little while to tell my story."

  "The night is young." Bat rose from his seat and went padding across to the kitchen, a great black-shrouded sack of flesh surmounted by a face that frowned now only with pleasurable anticipation. "I rely on you, as Torquemada, not to waste my time with trifles." He began to empty packets of orange jujubes, peppermint bonbons, and chocolates into a large ceramic bowl. "And for a satisfactory puzzle? Why, with adequate nourishment for the brain, no time to the end of the universe can be too much."

  10

  Outward Bound

  Time, thought Nell. Here was the oddest thing about subjective time. When you were running along in the studio-production routine of meetings and splicing and editing, time shrank. At the end of the week, you had no idea of where the days had gone. But if you went somewhere new, to a place you had never been before, and worked with a whole different group of people, then—time stretched.

  Like now. She had been on Ganymede for less than a day. Already it felt like forever.

  She stared at the watch handed to her the previous evening, and wondered what time it was. The wristwatch showed four-fifty. But Ganymede, like the rest of the Outer System, had changed after the war to SDT: Standard Decimal Time. She would have to drill that timekeeping method into her head until it seemed natural. A twenty-four-hour Earth day was equal to ten standard decimal hours, each of one hundred decimal minutes, each minute of a hundred decimal seconds. So the decimal second was a little bit shorter than the second that Nell was used to. There were 100,000 decimal seconds in an Earth day, rather than the usual 86,400 seconds.

  Fine. She herself had never found anything wrong with the old nondecimal twenty-four-hour/sixty-minute/sixty-second system, although the Ganymedeans mocked it as being as old-fashioned as fathoms, feet, fortnights, and furlongs. But meanwhile, just what the hell was the time? Her appointment with Hilda Brandt had been made for eleven—but eleven on Earth's timekeeping system.

  Nell did the conversion as she checked her appearance in the mirror. (Simple clothes, no makeup. Just the one plain brooch on her blouse. She should have had the sense to prepare herself this way before the first time she met Brandt.) Four-fifty Ganymede time meant four and a half decimal hours, which was a bit less than half the day of ten decimal hours. So it was still morning, and four-and-a-half tenths—nine-twentieths—of the way through the day. Nine-twentieths of twenty-four. A bit before eleven o'clock in the old Earth measure.

  Which meant that she was close to being late. And late was the same in any system of measurement.

  Nell hurried along the corridor from her sleeping quarters, making slower progress than she desired because she could not find an efficient low-gravity gait. She was off the floor too long between steps, and if she tried to speed up, she simply lifted higher and went slower. The maintenance machines knew. They froze at her approach, although they carried on their work as usual around everyone else. The Ganymedeans whom she passed didn't freeze. They just watched, and grinned at her efforts.

  She finally reached the elevator leading toward the surface and jumped aboard, wishing that she felt more like grinning herself.

  At the moment, she felt betrayed. Logic told her that the feeling was nonsense. Jon Perry had not asked her to come with him to the Jovian system. It had not been his idea at all. She had forced herself on him, explaining that Glyn Sefaris wanted to do a program about the Galileian satellites. It had taken another effort to persuade Jon that since they were both going, it made sense for them to travel on the same transit vehicle. And yesterday she'd had to push him to introduce her to Hilda Brandt.

  He had promised her nothing, made no commitment to her. He owed her not one thing, except perhaps to return the trivial favor of her providing him with a place to stay while he was in Arenas.

  So just what was upsetting her so much about the obvious way that Jon Perry and Wilsa Sheer had been bowled over by each other? She liked Jon. She admitted that. Liked him a lot. But did she like him that much? And in that way?

  Glyn Sefaris, in his passing reference to Nell's old affair with Pablo Roballo, had been giving her a warning: "You have a job to do. Don't let your personal feelings get in the way of it—the way you did before." Did she need that warning? Nell resented even the suggestion. Her job required that she stay physically close to Jon Perry, but that didn't mean she had to be emotionally close. She would find a way to go to Europa with Jon, but that was only to fulfill her assignment. And the need to reach Europa made her imminent meeting with Hilda Brandt more important than any self-indulgent notions of personal rejection.

  Nell pushed aside her memory of Jon's quiet confidence in an emergency, of beautiful hands skipping across controls with uncanny speed and accuracy, of eyes that lit up with enthusiasm whenever he talked of the mystery and wonder of the deep ocean. It was the wrong time for that sort of thinking. She had reached the Assembly Suite, where she was to meet the Europan research director.

  Hilda Brandt had told her to go right along to the end of it, where Brandt would be found tucked away in the private-dining area. Nell glanced at her wristwatch again. Four fifty-six. Which meant in Earth time that it was eleven—eleven? She struggled to do the conversion in her head, and failed. Damn all decimal times. Why the devil didn't they give her a watch with both timekeeping systems on it?

  But she knew the answer to that. As long as you were allowed to use the old, you would never change to the new. People were people, here on Ganymede just as much as on Earth. That was why the Ganymedeans themselves had not managed to introduce a time system based on their own day-night cycle of a little more than an Earth week, matching the moon's revolution around Jupiter. Maybe in another generation they would force themselves to do that, too, and throw away all the old watches.

  Hilda Brandt was there as promised, sitting staring at a fist-sized woolly pink ball on the table in front of her. Nell had the incongruous thought that the woman was knitting, until she saw that the ball was moving.

  Brandt looked as motherly and good-natured as ever, her hair drawn back from her temples and her bright brown eyes peering at the round object as it crawled along the tabletop. She glanced up as Nell approached and chuckled at the expression on her face.

  "No, Nell Cotter, it's not alive. Not quite. And it's perfectly harmless. This is a form of Von Neumann they use on Callisto for the collection of surface metals. Vanadium, this one is after, and it must be disappointed with the tabletop. I'm being asked to test it on Europa."

  "I thought Europa's surface was all water-ice, except for Mount Ararat." Nell was delighted to move the conversation at once to the inner moon. "How can there be metals?"

  "Oh, metals don't stay on the surface. They gradually sink down into the ice, because Jupiter's field induces eddy currents that keep them warm. In a few million years they finish up on the Europan seabed. But there's a steady resupply from meteorite impact—all sizes from dust specks to big boulders. Anything bigger than gravel sinks and is gone in the first second because of impact heat, so this little dear isn't designed to swallow anything more tha
n a couple of millimeters across. But you'd be surprised at how much it can snuffle up over a few months."

  "So you'll approve the Von Neumann's use on Europa?"

  "Oh, no." Hilda Brandt was firm and matter-of-fact. Nell sensed a lot of strength beneath the easygoing exterior. "As I said, it's not quite alive, but there are live components to it. That makes it too big a risk of contamination. The whole point of Europa is that there must be no transfer of living materials. We are keeping it as a perfectly sterile world. A pristine planet." She smiled again. "But this one is awfully nice and cuddly. Here, feel it."

  She passed the warm ball across to Nell, who took it gingerly. The woolly tendrils ran across the surface of her hand, pronounced her vanadium-free, and settled quietly into her palm. If Hilda Brandt would not accept the risk of contamination by this little Von Neumann, how must she be feeling about the discovery of native life on Europa? But maybe protection of that life was the main reason Brandt was so worried about contamination . . .

  Life on Europa. Nell stroked the furry little pink ball—could it make a popular pet back on Earth?—and returned to her own worries. Never mind life on Europa, what about getting Nell Cotter on Europa?

  "What did you decide, Dr. Brandt?" No point in putting it off.

  Hilda Brandt could have had no doubt of what Nell meant, but she stared at her in surprise. "Didn't Dr. Perry tell you? I met with him first thing this morning. The submersible that he brought from Earth cannot be shipped to Europa for another few days, not until changes are made to remove any danger of contamination from it. But a primitive Jovian submersible that we already used for travel on Europa is ready for use again, and it is big enough to hold two people. There is no reason why another person should not go with Dr. Perry on his familiarization visit."