Cities in Flight

scientifically oriented man who does not know that he too is as thorough-going a mystic as a fakir lying on a bed of nails.

The Hevians were suspicious; they questioned the discovery first of all only on the subject of what it said it was saying. Theology could wait. If continuous creation was a fact, then primarily that ruled out that there should ever have been a monobloc in the history of the universe, or that there should ever be a heat-death; instead, it would always go along like this, world without end. Therefore, if the discovery was as fundamentally ambiguous as all such discoveries before had proven to be, it should in the same breath be implying exactly the opposite; ask it that question, and see what it says.

This singularly tough-minded approach paid off at once, though the further implications which it offered for inspection proved in no way easier to digest than the first and contrary set had been. Taking a long chance with the still largely unfamiliar machines, and with the precarious life of their entire planet, the Hevians shut down their spindizzies entirely and listened more intently.

In that utmost of dead silences, the upsetting whisper of continuous creation proved to have two voices. Each pinging birth-pang was not a single note, but a duo. As each atom of hydrogen leapt into being from nowhere into the universe of experience, a sinister twin, a hydrogen atom of anti-matter, came there in that instant to die, from … somewhere else.

And there it was. Even what had seemed to be fundamental, ineluctable proof of one-way time and continuous creation could also be regarded as inarguable evidence for a cyclical cosmology. In a way, to the Hevians, it was satisfying; this was physics as they knew it to be, an idiot standing at a crossroads shouting “God went that-away!” and managing to point down all four roads at once. Nevertheless, it left them a legacy of dread. This single many- barbed burr of a datum, which could have been obtained under no other circumstances, was also sufficient in itself to endorse the existence of an entire second universe of anti-matter, congruent point for point with the universe of experience of normal matter, but opposite to it in sign. What appeared to have been the birth of a hydrogen atom of anti-matter, simultaneous with the birth of the normal hydrogen atom, was actually its death; there was now no doubt that time ran backwards in the anti-matter universe, and so did the entropy gradient, one being demonstrably a function of the other.

The concept, of course, was old—so old, in fact, that Amalfi had difficulty in remembering just when in his lifetime it had become so familiar to him that he had forgotten about it entirely. Its revival here by the Hevians struck him at first as an exasperating anachronism, calculated only to get in the way of the real work of practical men. He was in particular rather scornful of the notion of a universe in which negative entropy could be an operating principle; under such circumstances, his rustily squeaking memory pointed out, cause and effect would not preserve even the rough statistical associations which they were allowed in the universe of experience; energy would accumulate, events would undo themselves, water would run uphill, old men would clump into existence out of the air and soil and unlearn their profitless ways back toward their mothers’ wombs.

“Which is what they do in any event,” Gifford Bonner had said gently. “But actually, I doubt that it’s that paradoxical, Amalfi. Both of these universes can be regarded as unwinding, as running down, as losing energy with each transaction. The fact that from our point of view the anti-matter universe seems to be gaining energy is simply a bias built into the way we’re forced to look at things. Actually these two universes probably are simply unwinding in opposite directions, like two millstones. Though the two arrows of time seem to be pointing in opposite directions, they probably both point downhill, like fingerboards at the crest of a single road. If the dynamics of it bother you, bear in mind that both are four dimensional continua and from that point of view both are wholly static.”

“Which brings us to the crucial question of contiguity,” Jake said cheerfully. “The point is, these two four- dimensional continua are intimately related, as the twin events the Hevians observed make very plain; which I suppose must mean that we must allow for a total of at least sixteen dimensions to contain the whole system. Which is no particular surprise in itself; you need at least that many to accommodate the atomic nucleus of average complexity comfortably. What is surprising is that the two continua are approaching each other; I agree with Miramon that the observations his people made can’t be interpreted any other way; up to now, the fact that gravitation in the two universes is also opposite in sign seems to have kept them apart, but that repulsion or pressure or whatever you want to call it is obviously growing steadily weaker. Somewhere in the future, the near future, it will decline to zero, there will be a Pythagorean point-for-point collision between the two universes as a whole—”

“—and it’s hard to imagine how any physical framework, even one that allows sixteen dimensions of elbowroom, will be able to contain the energy that’s going to be released,” Dr. Schloss said. “The monobloc isn’t even in the running; if it ever existed, it was just a wet firecracker by comparison.”

“Translation: blooey,” Carrel said.

“It’s perfectly possible that a rational cosmology is going to have to accommodate all three events,” Gifford Bonner said. “I mean by that the monobloc, the heat death, and this thing—this event that seems to fall midway between the two. Curious; there are a number of myths, and ancient philosophical systems, that allow for such a break or discontinuity right in the middle of the span of existence; Giordano Bruno, Earth’s first relativist, called it the period of Inter-destruction, and a compatriot of his named Vico allowed for it in what was probably the first cyclical theory of ordinary human history; and in Scandanavian mythology it was called the Ginnangu-Gap. But I wonder, Dr. Schloss, if the destruction is going to be quite as total as you suggest. I am nobody’s physicist, I freely confess, but it seems to me that if these two universes are opposite in sign at every point, as everyone at this meeting has been implying, then the result cannot be only a general transformation of the matter on both sides into energy. There will be energy transformed into matter, too, on just as large a scale, after which the gravitational pressure should begin to build up again and the two universes, having in effect passed through each other and exchanged hats, will begin retreating from each other once more. Or have I missed something crucial?”

“I’m not sure that the argument is as elegant as it appears on the surface,” Retma said. “That awaits Dr. Schloss’s mathematical analysis, of course; but in the meantime I cannot help but wonder why, for instance, if this simultaneous creation-interdestruction-destruction cycle is truly cyclical, it should have this ornamental waterspout of continuous creation attached to it? A machinery of creation which involves no less than three universal cataclysms in each cycle should not need to be powered by a sort of continuous drip; either the one is too grandiose, or the other is insufficient. Besides, continuous creation implies a steady state, which is irreconcilable.”

“I don’t know about that,” Jake said. “It doesn’t sound like anything the Milne transformations couldn’t handle; it’s probably just a clock function.”

“Defined, as I recall, as a mathematical expression about the size of a bottle of aspirin,” Carrel said ruefully.

“Well, there’s one thing I’m perfectly certain of,” Amalfi growled, “and that is that it’s damned unlikely anybody is going to be around to care about the exact results of the collision after it happens. At least not at the rate this hassle is going. Is there actually anything useful that we can do, or would we be better off spending all this time playing poker?”

“That,” Miramon said, “is exactly what we know least about. In fact it would appear that we know nothing about it whatsoever.”

“Mr. Miramon—” Web Hazleton’s voice spoke from the shadows and stopped. Obviously he was waiting to be told that he was breaking his promise not to interrupt, but it was as plain to Amalfi as it was to the rest of the group that he was interrupting nothing now; his voice had broken only a dead and despairing silence.

“Go ahead, Web,” Amalfi said.

“Well, I was just thinking. Mr. Miramon came here looking for somebody to help him do something he doesn’t know how to do himself. Now he thinks we don’t know how to do it either. But what was it?”

“He’s just said that he doesn’t know,” Amalfi said gently.

“That isn’t what I mean,” Web said hesitantly. “What I mean is, what would he like to do, even if he doesn’t know how to do it? Even if it’s impossible?”

Bonner’s voice chuckled softly in the still shipboard air. “That’s right,” he said, “the ends determine the means. A hen is only an egg’s device for producing another egg. Is that Hazleton’s grandson? Good for you, Web.”

“There are a good many experiments that ought to be performed, if only we knew how to design them,” Miramon admitted thoughtfully. “First of all, we ought to have a better date for the catastrophe than we have now;