Cities in Flight

The first omen that there was something wrong with this chromo of sub-microscopic and universal domesticity appeared, as all good omens should, in the skies. Back on Earth, nearly half a century before space flight, some astronomer whose name is quite lost had noticed that two or three of the millions of meteors that entered Earth’s atmosphere every day exploded at a height and with a violence which could not be accounted for by an eccentricity of orbit or velocity; and in one of those great flights of fancy which account in the long run for every new link in the great chain of understanding, he had a dream of something which he called “contra-terrene” matter—a matter made of fire with cat’s fur, which would be circled by cats in flames: matter in which the fundamental hydrogen atom would have a nucleus which would be an anti-proton, with the mass of a proton but carrying a negative charge, around which would orbit an anti-electron, with the negligible mass of an electron, but carrying a positive charge. A meteor of atoms constructed on this model, he reasoned, would explode with especial violence at the first contact with even the faintest traces of Earth’s normal-matter atmosphere; and such meteors would suggest that somewhere in the universe there were whole planets, whole suns, whole galaxies composed of such matter, whose barest touch would be more than death—would be ultimate and complete annihilation, each form of matter converting the other wholly into energy in a flaming and total embrace.

Curiously, the contra-terrene meteors died out of the theory shortly thereafter, while the theory itself survived. The exploding meteors were found to be easier to explain in more conventional terms, but anti-matter survived, and by the middle of the Twentieth Century experimental physicists were even able to produce the stuff a few atoms at a time. Those topsy-turvy atoms proved to be nonviable beyond a few millionths of a micro-second, and it gradually became clear that even in this short lifetime the time in which they lived was running backwards. The particles of which they were made were born, in the great clumsy bevatrons of that age, some micro-seconds in the future, and their assembly into atoms of antimatter in the present time of the observers was in fact the moment of their death. Obviously anti-matter was not only theoretically possible, but could exist; but it could not exist in this universe in any assemblage so gross as a meteor; if there were worlds and galaxies made of anti-matter, they existed only in some unthinkable separate continuum where time and the entropy gradient ran backwards. Such a continuum would require at least four extra dimensions, at a minimum, in addition to the conventional four of experience.

As the universe of normal matter expanded, unwound and ran down toward its inevitable heat-death, somewhere nearby and yet in a “somewhere” unimaginable by man, a duplicate universe as vast and complex was contracting, winding up, approaching the supernal concentration of mass and energy called the monobloc. As complete dispersion, darkness and silence was to be the fate of the universe in which the arrow of time pointed down the entropy gradient, so in the anti-matter universe the end was to be mass beyond mass, energy beyond energy, raw glare and fury to the ultimate power raging in a primeval “atom” no bigger across than the orbit of Saturn. And out of one universe might come the other; in the universe of normal matter the monobloc was the beginning, but in the universe of anti-matter it would be the end; in a universe of normal entropy, the monobloc is intolerable and must explode; in a universe of negative entropy, the heat-death is intolerable and must condense. In either case, the command is: Let there be light.

What the visible, tangible universe had been like before the monobloc was, however, agreed to be forever unknowable. The classic statement had been refuted many centuries earlier by St. Augustine, who, when asked what God might have been doing before He created the universe, denied that He was constructing a hell for persons who asked such questions; thus “pre-Augustinean time” came to be something that a historian could know all about, but a physicist, by definition, nothing.

Until now; for if the Hevians were right, they had lifted that curtain a little way and caught an instant’s glimpse of the unknowable.

To have looked it full in the face could have been no more fatal.