This is not the only universe; far from it. It isn’t even the only universe in which life exists. Like living organisms, universes exist balanced on the edge of chaos, little bubbles of twisted urspace that pinch off and bloat outward, expanding and cooling, presently giving birth to further bubbles of condensed space-time; a hyperdimensional crystal garden full of strange trees bearing stranger fruit.
But the other universes are not much use to us. There are too many variables in the mix. As the initial burst of energy that signals the birth of a universe cools, the surging force field that drives its initial expansion becomes tenuous, then breaks down into a complex mess of other forces. The constants that determine their relative strengths are set casually, randomly. There are universes with only two forces; others, with thousands. (Ours has five.) There are universes where the electron is massive: nuclear fusion is so easy there that the era of star formation ends less than a million of our years after the big bang.
Chemistry is difficult there, and long before life can evolve, such universes contain nothing but cooling pulsars and black holes, the debris of creation brought to a premature end.
There are universes where photons have mass — others where there is too little mass in the universe for it to achieve closure and collapse in a big crunch at the end of time. There are, in fact, an infinity of universes out there, and they are all uninhabitable. There is a smaller infinitude of possibly habitable ones, and in some of them, intelligent life evolves; but more than that we may never know. Travel between universes is nearly impossible; materials that exist in one may be unstable in another. So, trapped in our little fishbowl of space we drift through the crystal garden of universes — and our own neighborly intelligences, beings like the Eschaton, do their best to prevent the less-clever inmates from smashing the glass from within.
The man in gray had explained all this to Martin at length, eighteen years ago. “The Eschaton has a strong interest in maintaining the integrity of the world line,” he had said. “It’s in your interest, too. Once people begin meddling with the more obscure causal paradoxes, all sorts of lethal side-effects can happen. The Eschaton is as vulnerable to this as any other being in the universe — it didn’t create this place, you know, it just gets to live in it with the rest of us. It may be a massively superhuman intelligence or cluster of intelligences, it may have resources we can barely comprehend, but it could probably be snuffed out quite easily; just a few nuclear weapons in the right place before it bootstrapped into consciousness, out of the preSingularity networks of the twenty-first century. Without the Eschaton, the human species would probably be extinct by now.”
“Epistemology pays no bills,” Martin remarked drily. “If you’re expecting me to do something risky …”
“We appreciate that.” The gray man nodded. “We need errands run, and not all of them are entirely safe.
Most of the time it will amount to little more than making note of certain things and telling us about them — but occasionally, if there is a serious threat, you may be asked to act. Usually in subtle, undetectable ways, but always at your peril. But there are compensations.”
“Describe them.” Martin put his unfinished drink down at that point.
“My sponsor is prepared to pay you very well indeed. And part of the pay — we can smooth the path if you apply for prolongation and continued residency.” Life-extension technology, allowing effectively unlimited life expectancy beyond 160 years, was eminently practical, and available on most developed worlds. It was also as tightly controlled as any medical procedure could be. The controls and licensing were a relic of the Overshoot, the brief period in the twenty-first century when Earth’s population blipped over the ten-billion mark (before the Singularity, when the Eschaton bootstrapped its way past merely human intelligence and promptly rewrote the rule book). The aftereffects of overpopulation still scarred the planet, and the response was an ironclad rule — if you want to live beyond your natural span, you must either demonstrate some particular merit, some reason why you should be allowed to stay around, or you could take the treatment and emigrate. There were few rules that all of Earth’s fractured tribes and cultures and companies obeyed, but out of common interest, this was one of them. To be offered exemption by the covert intervention of the Eschaton—
“How long do I have to think about it?” asked Martin.
“Until tomorrow.” The gray man consulted his notepad. ‘Ten-thousand-a-year retainer. Ten thousand or more as a bonus if you are asked to do anything. And an essential status exemption from the population committee. On top of which, you will be helping to protect humanity as a whole from the actions of some of its more intemperate — not to say stupid— members. Would you care for another drink?“
“It’s alright,” said Martin. They’re willing to pay me? To do something I’d volunteer for? He stood up. “I don’t need another day to think about it. Count me in.” The gray man smiled humorlessly. “I was told you’d say that.” The gold team was on full alert. Not a head moved when the door opened, and Captain Mirsky walked in, followed by Commodore Bauer and his staff. “Commander Murametz, please report.”
“Yes, sir. Time to jump transition, three-zero-zero seconds. Location plot confirmed, signals operational.
All systems running at an acceptable level of readiness for engagement plan C. We’re ready to go to battle stations whenever you say, sir.”
Mirsky nodded. “Gentlemen, carry on as ordered.” The Commodore nodded and quietly instructed his adjutant to take notes. Elsewhere on the ship, sirens blatted: the clatter of spacers running to their stations didn’t penetrate the bulkheads, but the atmosphere nevertheless felt tense. Low-key conversations started at the various workstations around the room as officers talked over the tactical circuits.
“Ready for jump in two-zero-zero seconds,” called Relativistics.
Rachel Mansour — wearing her disarmament inspector’s uniform — sat uncomfortably close to one of the walls, studying a packed instrument console over the shoulder of a petty officer. Brass handles and baroque red LEDs glowed at her; a pewter dog’s head barked silently from an isolation switch.
Someone had spent half a lifetime polishing the engravings until they gleamed as softly as butter. It seemed a bitter irony, to observe such art in a place of war; the situation was, she thought, more than somewhat repulsive, and finding anything even remotely beautiful in it only made things worse.
The Festivaclass="underline" of all the stupid things the New Republic might attack, the Festival was about the worst.
She’d spoken to Martin about it, piecing together his information with her own. Together they’d pieced together a terrifying hypothesis. “Herman was unusually vague about it,” Martin admitted. “Normally he has a lot of background detail. Every word means something. But it’s as if he doesn’t want to say too much about the Festival. They’re — he called them, uh, glider-gun factories. I don’t know if you know about Life—”
“Cellular automata, the game?”
“That’s the one. Glider guns are mobile cellular automata. There are some complex life structures that replicate themselves, or simpler cellular structures; a glider-gun factory is a weird one. It periodically packs itself into a very dense mobile system that migrates across the grid for a couple of hundred squares, then it unpacks itself into two copies that then pack down and fly off in opposite directions.