Luru Parz walked over the ice. “Once this was a mine. Nothing more sinister than that. But when I was last here the mine had long been shut down. Chambers like this, and the tunnels and shafts that linked them, had been pressurized and occupied. There was equipment here.” She pointed to notches in the floor. “That was a kind of bed, I remember.”
Pirius had been expecting something like Mons Olympus, some kind of library with bots and toiling archivists, Coalescent or not. “There’s nothing here,” he said. “Was this the library?”
“This never was a library,” Luru Parz said. “This was a laboratory.”
“Then where?”
“Through there.” She pointed to the door that led nowhere.
There was a moment of stiff silence, as Pirius looked from one to the other. He said, “I think you ought to tell me what’s going on.”
Nilis stared at him, agonized. Then, his arms tucked into his sleeves, he padded to the bot. The bot’s carapace opened to reveal a tray of drinks that steamed in the cold. Nilis picked one up, cradling it in his hands. “Lethe, I need this. What a tomb of a place!”
Luru Parz watched this with contempt. “A man called Reth Cana worked here, Ensign. Long ago. Ostensibly he came to look for life…”
Before humans came, nothing much had happened to this moon since it accreted from the greater cloud that had formed the Jupiter system. The inner moons — Io, Europa, Ganymede — had been heated by tidal pumping from Jupiter. Europa, under a crust of ice, had a liquid ocean; Io was driven by that perennial squeezing to spectacular volcanism. But Callisto had been born too far from her huge parent for any of that gravitational succor. Here, the only heat was a relic of primordial radioactivity; there had been no geology, no volcanism, no hidden ocean.
Nevertheless, Reth Cana had succeeded in his quest.
They were cryptoendoliths, Luru said, bacteria-like forms living hidden lives within the dirty ice of Callisto. They survived in rivulets of water, kept liquid by the heat of relic radioactivity, and they fed off the traces of organic matter locked into the ice at the time of the moon’s formation.
Luru Parz said, “The biochemistry here is a matter of carbon-carbon chains and water — like Earth’s, but not precisely so. Energy flows thin here, and replication is very slow, spanning thousands of years. The cryptoendoliths themselves weren’t so interesting — except for one thing.”
Reth had believed there were pathways of chemical and electrical communication, etched into the ice and rock, tracks for great slow thoughts that pulsed through the substance of Callisto. Locked into their ice moon, there had been few routes of development open to the cryptoendoliths. But, as always, life complexified, and sought new spaces to colonize. “The cryptoendoliths couldn’t move up or down, forward or back. So they stepped sideways…”
Nilis asked coldly, “Was Reth Cana an immortal, Luru?”
“A pharaoh, yes. But not a jasoft, not a collaborator. He was a refugee, in fact; he came here fleeing the Qax, and waited out the Occupation. Of course, as soon as the Occupation was lifted, he became a refugee once more, hiding from the Coalition and its ideologies. He returned here to escape. And he helped others do likewise.”
Pirius said, “What do you mean, these bugs grew sideways?”
“I mean,” said Luru Parz, “that these remarkable little creatures found a way to penetrate another universe. And not just any old universe. Ensign, do you know what is meant by configuration space?”
“Imagine there is no time. Imagine there is no space…” In the still cold of Callisto, as she described extraordinary ideas, Luru’s voice was a dry rustle.
“Take a snapshot of the universe. You have a static shape, a cloud of particles each frozen in flight at some point in space.” A snapping of fingers. “Do it again. There. There. There. Each moment, each juggling of the particles, gives you a new configuration.
“Imagine all those snapshots, all the possible configurations the particles of the universe can take. In any one configuration you could list the particles’ positions. The set of numbers you derive would correspond to a single point on a mighty multidimensional graph. The totality of that graph would be a map of all the possible states our universe could take up. Do you see? And that map is configuration space.”
“Like a phase space map.”
“Like a phase space, yes. But of the whole universe. Now imagine putting a grain of dust on each point of the map. Each grain would correspond to a single point in time, a snapshot. This is reality dust, a dust of the Nows. Reality dust contains all the arrangements of matter there could ever be…”
Slowly, as Luru explained and Nilis tried to clarify, Pirius began to understand.
Configuration space was not Pirius’s world, not his universe. It was a map, yes, a sort of timeless map of his own world and all its possibilities, a higher realm. And yet, according to Luru Parz, it was a universe in itself, a place you could go, in a sense. And it was filled with reality dust. Every grain of sand there represented an instant in his own universe, a way for the particles of his universe, atoms and people and stars, to line themselves up.
But this was a static picture. What about time? What about causality?
If you lined up reality dust grains in a row you would get a history, of a sort, Luru Parz said. But it might not make sense as a history; nothing like causality might emerge, just a jumble of disconnected snapshots one after another. But the sand grains attracted each other. If they came from neighboring points in the greater configuration space, the graph of all possible instants, the moments they mapped must resemble each other. And so the grains lined up in chains, each line of grains representing a series of instants which, if you watched them one after another, would give you the illusion of movement, the illusion of time passing — perhaps, if the grains were similar enough, even the illusion of causality.
Something like that.
And configuration space, he slowly understood, was where Luru Parz wanted to send Pirius.
It was beyond his imagination. “You want me to go into a map? How is that possible?”
Luru said, “Reth Cana discovered that, constrained in this space and time, the endoliths found a way into configuration space — and Reth Cana found a way for humans to follow. He could download a human consciousness into this abstract realm.”
“I can see the appeal of that for pharaohs,” Nilis said with dark humor. “An abstract, static, Platonic realm — a place of morbid contemplation, a consolation for ageless pharaohs as they sought to justify the way they administered the suffering of their fellow creatures.”
Luru Parz smiled thinly. “Of course it is a realm beyond our experience. So Reth constructed metaphors, a kind of interface to make its features accessible to human minds. There is an island — a beach. You’ll see a mountain, Pirius, and a sea. The mountain is order, and at its peak is that special dust grain that represents the initial singularity: the Big Bang, the unique event when all the universe’s particles overlaid each other.”
Pirius said, “And the sea?”
“The sea is the opposite. The sea is disorder — maximal entropy — the ocean of meaninglessness to which everything washes, in the end.”
Pirius stood before the doorway, set up in the abandoned laboratory of Reth Cana. It looked as if it led nowhere. In fact, Luru Parz was saying, it led to a different realm of reality altogether. “And if I walk through this door—”
“You will split in two,” Luru said. “You will still be here, walking out the other side. But a copy of you will be made.”