Corny, yes, thought Kate, but undeniably effective; the audience was gazing spellbound at Hiram’s giant image as the music of a summer seven decades gone reverberated around the cafeteria.

“And now,” said Hiram with a showman’s nourish, “I believe I have achieved my life’s goal. I’d suggest holding on to something — even someone else’s hand…”

The floor turned transparent.

Suddenly suspended over empty space, Kate felt herself stagger, her eyes deceived despite the solidity of the floor beneath her feet. There was a gale of nervous laughter, a few screams, the gentle tinkle of dropped glass.

Kate was surprised to find she had grabbed on to Bobby’s arm. She could feel a knot of muscle there. He had covered her hand with his, apparently without calculation.

She let her hand stay where it was. For now.

She seemed to be hovering over a starry sky, as if this cafeteria had been transported into space. But these “stars,” arrayed against a black sky, were gathered and harnessed into a cubical lattice, linked by a subtle tracery of multi-coloured light. Looking into the lattice, the images receding with distance, Kate felt as if she were staring down an infinitely long tunnel.

With the music still playing around him — so artfully, subtly different from the original recording — Hiram said, “You aren’t looking up into the sky, into space. Instead you are looking down, into the deepest structure of matter. This is a crystal of diamond. The white points you see are carbon atoms. The links are the valence forces that join them. I want to emphasize that what you are going to see, though enhanced, is not a simulation. With modern technology-scanning tunnelling microscopes, for instance — we can build up images of matter even at this most fundamental of levels. Everything you see is real. Now — come further.”

Holographic images rose to fill the room, as if the cafeteria and all its occupants were sinking into the lattice, and shrinking the while. Carbon atoms swelled over Kate’s head like pale grey balloons; there were tantalizing hints of structure in their interior. And all around her space sparkled. Points of light winked into existence, only to be snuffed out immediately. It was quite extraordinarily beautiful, like swimming through a firefly cloud.

“You’re looking at space,” said Hiram. “’Empty’ space. This is the stuff that fills the universe. But now we are seeing space at a resolution far finer than the limits of the human eye, a level at which individual electrons are visible — and at this level, quantum effects become important. ‘Empty’ space is actually full, full of fluctuating energy fields. And these fields manifest themselves as particles: photons, electron-positron pairs, quarks… They flash into a brief existence, bankrolled by borrowed mass-energy, then disappear as the law of conservation of energy reasserts itself. We humans see space and energy and matter from far above, like an astronaut flying over an ocean. We are too high to see the waves, the flecks of foam they carry. But they are there.

“And we haven’t reached the end of our journey yet. Hang on to your drinks, folks.”

The scale exploded again. Kate found herself flying into the glassy onion-shell interior of one of the carbon atoms. There was a hard, shining lump at its very centre, a cluster of misshapen spheres. Was it the nucleus? — and were those inner spheres protons and neutrons?

As the nucleus flew at her she heard people cry out. Still clutching Bobby’s arm, she tried not to flinch as she hurtled into one of the nucleons.

And then…

There was no shape here. No form, no definite light, no colour beyond a blood-red crimson. And yet there was motion, a slow, insidious, endless writhing, punctuated by bubbles which rose and burst. It was like the slow boiling of some foul, thick liquid.

Hiram said, “We’ve reached what the physicists call the Planck level. We are twenty order of magnitudes deeper than the virtual-particle level we saw earlier. And at this level, we can’t even be sure about the structure of space itself: topology and geometry break down, and space and time become untangled.”

At this most fundamental of levels, there was no sequence to time, no order to space. The unification of spacetime was ripped apart by the forces of quantum gravity, and space became a seething probabilistic froth, laced by wormholes.

“Yes, wormholes,” Hiram said. “What we’re seeing here are the mouths of wormholes, spontaneously forming, threaded with electric fields. Space is what keeps everything from being in the same place. Right? But at this level space is grainy, and we can’t trust it to do its job any more. And so a wormhole mouth can connect any point, in this small region of spacetime, to any other point — anywhere: downtown Seattle, or Brisbane, Australia, or a planet of Alpha Centauri. It’s as if spacetime bridges are spontaneously popping into and out of existence.”

His huge face smiled down at them, reassuring. “I don’t understand this any more than you do,” the image said. “Trust me.”

“My technical people will be on hand later to give you background briefings in as much depth as you can handle.

“What’s more important is what we intend to do with all this. Simply put, we are going to reach into this quantum foam and pluck out the wormhole we want: a wormhole connecting our laboratory, here in Seattle, with an identical facility in Brisbane, Australia. And when we have it stabilized, that wormhole will form a link down which we can send signals — beating light itself.

“And this, ladies and gentlemen, is the basis of a new communications revolution. No more expensive satellites sandblasted by micrometeorites and orbit-decaying out of the sky; no more frustrating time delay; no more horrific charges — the world, our world, will be truly linked at last.”

As the virtuals kept playing there was a hubbub of conversation, even heckling questions. “Impossible!”

“Wormholes are unstable. Everyone knows that.”

“Infalling radiation makes wormholes collapse immediately.”

“You can’t possibly -”

Hiram’s giant face loomed over the seething quantum foam. He snapped his fingers. The quantum foam disappeared, to be replaced by a single artefact, hanging in the darkness below their feet.

There was a soft sigh.

Kate saw a gathering of glowing light points — atoms? The lights made up a geodesic sphere, closed over itself, slowly turning. And within, she saw, there was another sphere, turning in the opposite sense — and within that another sphere, and another, down to the limits of vision. It was like some piece of clockwork, an ornery of atoms. But the whole structure pulsed with a pale blue light, and she sensed a gathering of great energies.

It was, she admitted, truly beautiful.

Hiram said, “This is called a Casimir engine. It is perhaps the most exquisitely constructed machine ever built by man, a machine over which we have laboured for years — and yet it is less than a few hundred atomic diameters wide.

“You can see the shells are constructed of atoms — in fact carbon atoms; the structure is related to the natural stable structures called ‘buckyballs,’ carbon-60. You make the shells by zapping graphite with laser beams. We’ve loaded the engine with electric charge using cages called Penning traps — electromagnetic fields. The structure is held together by powerful magnetic fields. The various shells are maintained, at their closest, just a few electrons’ diameters apart. And in those finest of gaps, a miracle happens…”

Kate, tiring of Hiram’s wordy boasting, quickly consulted the Search Engine. She learned that the “Casimir effect” was related to the virtual particles she had seen sparkling into and out of existence. In the narrow gap between the atomic shells, because of resonance effects, only certain types of particles would be permitted to exist. And so those gaps were emptier than “empty” space, and therefore less energetic.