Behind all this bad behaviour was an insecurity magnificent in scope, metaphysical in nature. Space was big, and the boys from Earth were awed despite themselves by the things they found there: but worse, their science was in a mess. Every race they met on their way through the Core had a star drive based on a different theory. All those theories worked, even when they ruled out one another’s basic assumptions. You could travel between the stars, it began to seem, by assuming anything. If your theory gave you a foamy space to work with—if you had to catch a wave—that didn’t preclude some other engine, running on a perfectly smooth Einsteinian surface, from surfing the same tranche of empty space. It was even possible to build drives on the basis of superstring-style theories, which, despite their promise four hundred years ago, had never really worked at all.

It was affronting to discover that. So when they fetched up on the edge of the Tract, looked it in the eye, and began to despatch their doomed entradas, the Earthlings were hoping to find, among other things, some answers. They wondered why the universe, which seemed so harsh on top, was underneath so pliable. Anything worked. Wherever you looked, you found. They were hoping to find out why. And while the entradistas were dying in ways no one could imagine, crushed, fried, expanded or reduced to mists of particles by the Tract itself, lesser hearts took with enthusiasm to the Beach, where they found Radio Bay. They found new technologies. They found the remains of ancient races, which they ragged about like bull terrier pups with an old bone.

They found artificial suns.

There had been, some time in the deep past, such a premium on the space closest to the Tract that there were more artificial suns in the Radio Bay cluster than natural ones. Some had been towed in from other locations; others had been built from scratch, in situ. Planets had been steered into place around them, and inserted into unnatural orbits designed to keep the Tract in maximum view. Ferociously goosed magnetic fields and ramped-up atmospheres protected them from radiation. Between the planets, under the sleets of raging light, rogue moons wove their way, in fantastically complex orbits.

These were less star systems than beacons, less beacons than laboratories, and less laboratories than experiments in themselves: enormous detectors designed to react to the unimaginable forces pouring out of the uncontained singularity hypothetically present at the centre of the Tract.

This object was massively energetic. It was surrounded by gas clouds heated to 50,000 degrees Kelvin. It was pumping out jets and spumes of stuff both baryonic and non-baryonic. Its gravitational effects could be detected, if faintly, at the Core. It was, as one commentator put it: “a place that had already been old by the time the first great quasars began to burn across the early universe in the unimaginable dark.” Whatever it was, it had turned the Tract around it into a region of black holes, huge natural accelerators and junk matter—a broth of space, time, and heaving event horizons; an unpredictable ocean of radiant energy, of deep light. Anything could happen there, where natural law, if there had ever been such a thing, was held in suspension.