The Apocalypse Troll

"That's where the Many-Worlds Theory comes in," Hastings said. "But even if Everett was right-" She shook her head. "I don't even know where to start looking for questions, much less what the answers might be!"

"Neither does anyone where I come from," Ludmilla said wryly. "Look, the whole theory behind a Takeshita Translation is just that: theory. No one's ever tried one-or reported back afterward, anyway-and the argument over what ought to happen during one has gone on for a century and a half.

"Jayne, you mentioned the Copenhagen School and the Many-Worlds Theory. We don't use that terminology anymore, but I know what you mean, and the fundamental problem remains, because there's still no way to test either theory." Aston and Morris looked utterly confused, and she made a face.

"Bear with me a minute, you two," she said, "and I'll do my ignorant best to explain, all right?" They nodded, and she went on.

"In its simplest terms, what Jayne is talking about is one of the major problems involved in understanding quantum mechanics. There's been a lot of progress since the twenty-first century, but I'm just a fighter jock." She used Aston's terminology with a wry grin.

"Essentially, there's been a dispute over the basic nature of what we fondly call 'reality' almost since Einstein. According to the math, any possible interaction-or, rather, the result of any interaction-is a superposition of functions, each of which represents one possible outcome of the interaction. With me so far?"

"Are you saying that mathematically speaking any of the outcomes is equally valid?" Aston sounded skeptical, and she patted his bald pate playfully.

"For a nullwit, that's not bad," she said teasingly. "Not quite right, but it'll do for starts. You see, the problem is that for any interaction, we observe one-and only one-outcome, but the math says the potential for all possible outcomes is bound up in the event. Now, what Jayne is calling the Copenhagen School says that at the moment a wave function-" She paused and grimaced, then resumed as if re-selecting her words. "Well, at the moment an interaction occurs, the whole thing collapses into a single one of the elements of possibility, and the others never come into existence at all. The potentiality of all outcomes remains up until that moment, and none of them can be absolutely ruled out, but a weighted probability distribution can be assigned to them, which allows the effective prediction of which single event will actually occur. Follow me?"

"Yes, but I'm losing a little ground. How about you, Mordecai."

"Quit asking me to expose my ignorance. You were saying, Colonel?"

"All right. An alternative hypothesis, proposed sometime in the last century, says, simply, that rather than a single event, all possible outcomes occur, however 'probable' or 'improbable' they may be. We observe only one, true, but that's because the others occur on different 'stems' of reality."

"Parallel worlds, right?" Aston nodded. "Our sci-fi writers love 'em."

"They still do back home," Ludmilla assured him. "Anyway, Jayne's Copenhagen School-we call it the Classic School-maintains that there is one and only one reality; a single, linear reality in which the single realized outcome of each interaction is defined and creates the preconditions for the next. What we call the Revisionist School-Jayne's 'Many-Worlds' theory-has gained a tremendous amount of ground in the last couple of hundred years, though, and some of its proponents claim that eventually they'll be able to demonstrate its validity through some esoteric manipulation of the multi-dee. I've seen the math on it, and it gives me headaches just to think about it; I certainly don't understand it. But the Revisionist School says that instead of a single reality, there are multiple realities, all branching off from a common initial source, all equally 'real,' but never interfacing."

"So where does all this fit into time travel?" Aston asked, but a gleam in his weary eyes suggested that he saw where she was headed.

"There are three main theories as to what happens in a Takeshita Translation," Ludmilla said. "One says that the whole thing is impossible; anyone who tries one simply goes acoherent and stays there. It's neat, at least, but my survival is empirical evidence that it doesn't work.

"Theory number two is Takeshita's First Hypothesis, and it says that anyone making a Takeshita Translation travels backward along the single reality stem of the Classic School. There are some problems with it, but, essentially, it says that when the traveler stops moving-drops back into phase with reality, as it were-he becomes an event which has been superimposed upon the reality stem. He, personally, exists, wherever he came from and however he got there. But since he exists, he can affect the universe, which will inevitably affect the nature of reality 'downstream' from him, with the result that-as Commander Morris put it-you really could murder your grandfather without erasing yourself. Your existence is pegged to a reality which preexists the one in which you were never born.

"Takeshita spent years on the math to support that theory, but in the last years of his life he became convinced that the Revisionists had been right all along, which created a furor amongst his followers, I can tell you! Anyway, he propounded his Second Hypothesis, which says, essentially, that the classic arguments against paradox are valid after all-that it's impossible for an individual to move into his own past. By the act of moving backward in time, he does, indeed, superimpose his existence on events, but, in the process, he causes the stream of reality to split off another tributary. In effect, he avoids paradox by forcing a divergence of 'his' subsequent personal reality line from the one which created him.

"The problem, of course," she ended with a whimsical smile, "is that no hard experimental data was ever available. Until now, that is."

Silence threatened to stretch out indefinitely until Jayne Hastings finally broke it.

"So which theory's correct?" she asked softly.

"Let's start with the basics," Ludmilla suggested. "I am here-and so is the Troll. Task Force Twenty-Three was attacked and did shoot down two Troll fighters. Those facts seem to prove that whatever happened is possible, and, further, that the Troll can do whatever it intends to do unless we stop it. Those are the pragmatic considerations. Agreed?"

Three heads nodded, and she went on.

"All right. My own feeling is that Takeshita's Second Hypothesis applies, which means that the Revisionists were right, of course. And it also means that I'm not in my past, which neatly explains the absence of any recorded nuclear attack on a US Navy task force in 2007. It didn't happen in my reality-it happened in yours."

"You mean ... you're not just from the future, you're from someone else's future?" Aston sounded a bit shaken.

"Why not? Nick Miyagi could have explained it a lot better-he always did support the Second Hypothesis." Ludmilla smiled sadly. "He almost took time to argue the point with me when we saw it happening. But, yes, that's right. I'm not from your reality-your 'universe'-at all, Dick."

"But ..." Hastings frowned as she worked through the implications. "Excuse me again, but you seem to be saying you more than half-expected the Kangas to wind up in somebody else's past."

"I did."

"Then why try to stop them?" Hastings asked very quietly. "You say your battle division was totally destroyed, along with thousands and thousands of your people. Your own fighter squadron was destroyed-in fact, you're the only survivor from your entire force. Why in God's name take such losses when these 'Kangas' couldn't even hurt your time line at all?"

"Two reasons, really, I suppose," Ludmilla said after a moment. "First, of course, we couldn't be certain. Remember, Takeshita offered two hypotheses, and neither had ever been tested. What if he'd been right the first time, and the Kangas had changed our own history?" Hastings nodded slowly, but the question remained in her eyes, and Ludmilla smiled sadly.