A photon of just the right frequency, impacting a pumped molecule, could cause the molecule to tip out of its unstable state. The molecule shed energy and emitted another photon of the same frequency. So the result was two photons, where one had been before… And the two photons stimulated two more atoms, resulting in four photons… A chain reaction followed, growing geometrically, with a flood of photons from the stimulated silicon monoxide molecules — all at the same microwave frequency, and all coherent — with the same phase.
Lieserl knew that to get significant maser effects, pumped molecules had to be arranged in a line of sight, to get a long path of coherence. The convection cells, with their huge, multimillion-mile journeys to the surface and back, provided just such pathways. Maser radiation cascaded up and down the long flanks of the cells, spearing into and out of the helium core.
The maser radiation could even escape from the Sun altogether, she saw. The convection founts grazed the surface, at their most extreme points; maser energy was blasted out, tangential to the surface of the swollen Sun, forming tiny, precise beacons of coherent light.
And the maser beacons were, she realized with a growing excitement, very, very distinctive.
Excited, she swept back and forth through the huge convection cells. It wasn’t difficult, she found, to disrupt the form of the coherent silicon monoxide maser beams; she imposed structure on the beams’ polarization, phasing and coherent lengths.
She started with simple signals: sequences of prime numbers, straightforward binary arrays of symbols. She could keep that up almost indefinitely; thanks to the time it took for the coherent radiation to reach their firing points at the surface, it was sufficient for her to return to the convection cells every few days to re-initiate her sequence of signals. She could trace echoes of her signals, in fact, persisting even in the downfalling sides of the cells.
Then, as her confidence grew, she began to impose meaningful information content on her simple signal structure. With binary representations of images in two and three dimensions, and with data provided in every human language she knew, she began to relate the story of what had happened to her, here in the heart of the Sun — and of what the photino birds were doing to mankind’s star.
Feverishly she worked at the maser signals, while the final death of the Sun unraveled.
In the stern galley of the Great Britain, Louise sat before her data desks. The little pod from the lifedome showed up as a block of pixels sliding past a schematic of the Northern.
Over the radio link she heard screams.
“Oh, for Lethe’s sake, Mark, don’t scare him completely out of his mind.”
Mark sounded hurt. “I’m doing my best.”
Louise felt too tired, too used up, to cope with this sudden flood of events.
She tried, sometimes, to remember how it had been to be young. Or even, not quite so old. It might have been different if Mark had survived, of course: his AS system had imploded after four centuries, not long after he and Louise had moved out of the lifedome and into the Britain. Maybe if Mark had lived, if she’d spent all these years with another person — not alone — she wouldn’t have ended up feeling so damn stale.
She comforted herself with the thought that, whatever was going on today, the Northern’s immense journey was nearing its end, now. Another few decades, when she had shepherded the wormhole Interface and motley inhabitants of the lifedome — those who’d survived among those battling, swarming masses — through all these dreadful years, she would be able to let go at last. Maybe she would implode then, she thought, like some dried-up husk.
She called up a projection of its trajectory. “Well, it’s not heading for the Britain,” she told Virtual-Mark. “It’s moving past us…”
A new voice came crackling out of her data desk now. “Arrow Maker. Arrow Maker. Listen to me. You must reach the Interface. Don’t let them stop you…”
To Louise, this was a voice from the dead past. It was distorted by age, almost reduced to a caricature, echoing as if centuries were empty rooms.
She localized the source of the transmission — a desk in the base of the lifedome, near the pod hangars — and she threw open a two-way link. “Uvarov? Garry Uvarov?”
The voice fell silent, abruptly.
She heard Mark, in the pod, saying, “Now just take it easy. I know this is strange for you, but I’m not going to hurt you.” A pause. “I couldn’t if I tried. I’ll tell you a secret: I’m not real. See? My hand is passing right through your arm, and — ”
More screams, even shriller than before.
Oh, Mark…
“Come on, Uvarov,” she said. “I know it’s you. I still recognize that damn Moon accent. Speak to me.”
“Oh, Lethe, Louise,” Mark reported, “he’s gone crazy. He’s grabbed the stick: he’s accelerating — right toward the Interface.”
Mark was right, she saw; the craft’s speed had increased, and it was clearly heading to where the wormhole Interface was cradled in its web of superconducting hoops, bound magnetically to the structure of the GUTship.
She punched in quick queries. Less than two minutes remained before the pod reached the Interface.
“Uvarov, listen to me,” she said urgently. “You must respond. Please.” While she spoke her hands flew over the desks; she ordered her processors to find some way to take control of the pod. She cursed herself, silently, for her carelessness. She’d had centuries, literally, to find ways of immobilizing the lifedome pods. But she’d never imagined this scenario, some crazy savage with a painted face taking a pod into the Interface while they were still relativistic.
Well, she damn well should have imagined it.
“Uvarov. You must respond. We’re still in flight.” She tried to imagine the old eugenicist’s condition, extrapolating wildly from the few words she’d heard him speak. “Uvarov, can you hear me? You have to stop him — the man in the pod, this Arrow Maker. He’ll destroy himself…” And, she thought sourly, maybe the whole damn ship as well. “You know as well as I do that the Interface can’t be used during the flight. The kinetic energy difference between our Interface and the one back in the past will make the wormhole unstable. If your Arrow Maker flies that pod in there, he’ll wreck the wormhole.”
“You’re lying,” Uvarov rasped. “The journey’s over. We’ve seen the stars.”
“Uvarov, listen to me. We’re still relativistic.” She turned to peer out of the galley’s small windows. The Britain was suspended beneath the belly of the lifedome, so that the dome was huge and brilliant above her; the spine pierced space a few hundred yards away. And, all around the spine, the starbow — the ring of starlight aberrated by their motion — gleamed dully, infinitely far away.
With a small corner of her mind, she longed to shut this out, to erect some Virtual illusion to hide in.
“I can see the damn starbow, Uvarov. With my own eyes, right now. We’re decelerating, but we’re still relativistic. We have decades of this journey ahead of us yet…” Was it possible Uvarov had forgotten?
In the background she could hear Mark’s voice patiently pleading with the primitive in the pod; her desks showed her endless representations of the processors’ failed attempts to override the pod’s autonomous systems, and the astonishingly rapid convergence of the pod with the Interface.