He grunted, and said, “There would be no point at all in the Polypheme trying to keep the final destination secret. The Marglotta would have been right there to answer our questions.”
“And therefore?”
“We didn’t blunder into this system by accident. It was intended that our ship would arrive, just where we did—and it must be possible to reach Marglot through a Bose transition point located right here.”
“Exactly. Which leaves a single question, but one with huge potential consequences: we can reenter the same node by which we came here. It is sitting a few minutes away. But what transition sequence from here might take us to Marglotta?”
Teri and Torran glanced across at one of the displays, where a faint circle of opalescence indicated the presence of the nearby Bose node.
The theory that explained the Bose network in terms of multi-connected spacetimes was so complex that very few people understood it. The practical use was another matter. It was often said that any fool with a suitably equipped ship could enter a Bose node; but that only an absolute fool would try it, without first being in possession of the eighty-four digits that specified the connection between an entry node and the desired exit point. Used correctly, the Bose network had a zero failure rate. Used incorrectly, by specifying an invalid digit stream, one of two things would happen. If you were lucky and you made an error in the entry point digits, the string would be rejected and you would pop back into normal space exactly where you had entered the node. If you were unlucky and you made an error in the exit point digits, you might know your fate but no one else would. Ships which were discovered by retrospective analysis to have used an invalid exit digit set were never heard from again.
“An impossible problem.” Julian Graves was closely watching the expression on the others’ faces. “We know where we are, which gives us the input coordinates for a Bose transition. We could follow the method used by Louis Nenda and the Have-It-All, pick some other Bose node, generate the entire digit string, make the jump, and hope we arrive where we want to be. With the screening process they propose, that certainly won’t be the Marglot system. But it might be a place where someone can tell them how to reach that system. Fairly simple, probably fairly safe, but at best an indirect approach. However, I don’t want just any exit node. I want the digit string of the correct exit node—in the Marglot system.”
Teri said, “Which means we must know the exact string of forty-two numbers. I don’t like those odds.”
“Nor do I. I asked—or, to be more specific, Steven, who is better at this kind of thing than I am, asked—how much those odds might be improved using other information. We cannot achieve certainty, that would be too much to ask for, but can we reduce the risk to an acceptable level?”
Torran Veck raised his eyebrows, which Teri took to mean, Are you out of your mind?
But no one spoke, until Julian Graves continued. “What do we know? Well, we have the exact sequences for a couple of thousand Bose nodes in our own Orion Arm, plus everything for the Bose nodes defined in the Sag Arm and held within the data bank of the Polypheme’s ship. If Bose digit strings were random, that would not be any use at all. We would be ruling out only a few thousand numbers, and leaving endless trillions of trillions of possible but incorrect sequences. It does not take the computational powers of Steven or E.C. Tally to recognize that avenue leads nowhere. At the same time, I remained convinced that we were all missing something. The clue as to what that might be came when I was pondering the way that the Chism Polypheme at Miranda Port died. We know that a Polypheme will normally live for many thousands of years—we don’t know quite how many—before it succumbs to natural causes. That’s why it was so surprising to encounter a dead one. But turn that logic around. A Polypheme will live for ages, but it can be killed, like anything else, by violence or by accident. We often emphasize that Polyphemes don’t tell the truth, but maybe we should emphasize even more that they do not take risks. Think how averse to danger you would be if your normal life expectancy extended over many thousands of years. That tells us something else. No Polypheme would ever expose itself to the totally avoidable risk of attempting a Bose transition with an invalid digit string. And that has another implication.”
Torran said softly, “The Polypheme had all the sequences to bring us here. He must also have possessed the correct sequence to return to the final Marglot destination.”
“Exactly so. He would not have risked remembering it. Nor would he store the sequence in an open file. The number string must have been stored somewhere in the ship’s data banks, in a hidden place from which the Polypheme could recall it when it was needed.”
“But the data banks—” Teri paused. “They don’t have just millions or billions of numbers, they have many trillions of them. Everything from artifact catalogs to navigational data to engineering data. I’m sure they also contain all the standard encyclopedias for many worlds and many species.”
“Quite true. An impossible job, right, to find the forty-two digit sequence that we need? Impossible to us, that is—but not impossible to E.C. Tally. It’s a natural for him. Remember, he already downloaded everything in the Polypheme ship’s data banks into his own memory.
“I asked him to do four things. First, to take the known digit sequences of every known Bose node, and derive from them as many characteristic string properties and statistics as he could. Second, to sort out from the data banks of the Polypheme ship every discrete and identifiable forty-two-digit sequence—I knew there would be trillions of them. Third, to test every one of those sequences to see if they possessed the statistical properties derived from known Bose node sequences. And finally, to provide a ranked list of matches in order of their goodness of fit, together with some numerical measure of confidence in the result.”
Teri muttered, almost to herself, “An absolutely monstrous job.”
“Agreed. It is monstrous, even Steven admitted that it would be quite beyond him. But it’s meat and drink to an embodied computer like Tally. He ate it up. I had no idea how long it might take him, days or weeks or months. But he was finished in a few hours. Do you want to see the results?”
The councilor did not wait for an answer. A long table of figures appeared on the wall display behind him. While Torran and Teri studied it, he went on, “As you can see, we have no certainties, no hundred percent fit.”
“But isn’t that wrong?” Torran Veck was scowling at the screen. “If the number one choice really does represent a Bose node, shouldn’t it be on the list?”
“I don’t think so. The Chism Polypheme didn’t want his private navigation secrets revealed to anybody who tapped his ship’s data banks. He deliberately excluded the Bose coordinates of the final destination from his ‘official’ list of nodes.”
“Seventy-two percent probability.” Teri had scanned the whole list. “That’s the best fit. It’s not very good. And the next one is way down, at only eight percent odds.”
“Is the glass half full, or is it half empty? Seventy-two percent doesn’t sound too great, I agree. But it’s so enormously better than eight percent, what are the chances that one match so good would pop up at random?”
Torran said, “You tell us.”
“I’ll tell you what Steven says. It’s only one in a thousand that the digit string you are looking at isn’t a genuine Bose sequence. But that doesn’t mean most of you will survive if you try it and it’s wrong. It’s all, or it’s nothing. And I’m certainly not going to try to persuade you to take the risk. I’d be quite happy if you would agree to stay here, with the Pride of Orion, and serve to coordinate whatever anyone else learns.”