The Time Traveler's Almanac

“You’re standing on them.” Torque’s expression was one of restrained impatience: Weren’t you paying attention in class the day they covered this? “The plateau this reading room is built on – in fact, the entire upper crust – is riddled with storage cells of memory diamond, beneath a thin crust of sedimentary rock laid down to protect it. We switched the continental-drift cycle off for good about five billion years ago, after the last core cooling cycle. That’s when we began accumulating the Library deposits.

“Oh.” Pierce looked around. “Well, I suppose I’d better get started. Do you mind?”

“Not at all.” Torque turned his back on Pierce and walked away. “I’ll be around if you call me,” he sent.

Pierce sat down in front of the empty desk and laid his hands palm down on the blotter. A continent of memory diamond? The mere idea of that much data beggared the imagination. “It’ll be in here somewhere,” he muttered, and smiled.

Unhistory

One of the first things that any agent of the Stasis learns is patience. It’s not as if they are short of time; their long lives extend beyond the easy reach of memory, and should they avoid death through violence or accident or suicide, they can pursue projects that would exceed the life expectancy of ordinary mortals. And that is how they live in the absence of the principal aspect of their employment, the ability to request access to the timegate.

Pierce thought at first that the vice-chancellor’s request would be trivial, a matter of taking a few hours or days to dig down into the stacks and review the historical record. He’d return triumphant, a few minutes upstream of his departure, and present his findings before the council. Xiri would be appropriately adoring, and would doubtless write a series of sonnets about his Library visit (for poetics were in fashion as the densest rational format for sociological-academic case studies in Leng): and his adoptive home time would be spared the rigor and pity of a needless doctrinal war. That was his plan.

It came unglued roughly a week after his arrival, at the point when he stopped flailing around in increasing panic and went for a long walk around the paths of the biome, brooding darkly, trying to quantify the task.

Memory diamond is an astonishingly dense and durable data substrate. It’s a lattice of carbon nuclei, like any other diamond save that it is synthetic, and the position of atoms in the lattice represents data. By convention, an atom of carbon 12 represents a zero, and an atom of carbon 13 represents a one; and twelve-point-five grams of memory diamond – one molar weight, a little under half an old-style ounce – stores 6 × 1023 bits of data – or 10 23 bytes, with compression.

The continent the reading room is situated on is fifteen kilometers thick and covers an area of just under forty million square kilometers, comparable to North and South America combined in the epoch of Pierce’s birth. Half of it is memory diamond. There’s well over 1018 tons of the stuff, roughly 10 23 molar weights. One molar weight of memory diamond is sufficient to hold all the data ever created and stored by the human species prior to Pierce’s birth, in what was known at the time as the twenty-first century.

The civilizations over which the Stasis held sway for a trillion years stored a lot more data. And when they collapsed, the Stasis looted their Alexandrian archives, binged on stolen data and vomited it back up at the far end of time.

Pierce’s problem was this: more than 90 percent of the Library consisted of lies.

He’d started out, naturally enough, with two pieces of information: the waypoint in his phone that identified the exact location of the porch of his home in Leng, and the designation of the planetary system in M-33 that had aroused such controversy. It was true, as Xiri had said, that the Hegemony was reveling in the feed from the robot exploration fleet that had swept through the Triangulum galaxy tens of millions of years ago. And he knew – he was certain! – that Xiri, and the Hegemony, and the city of Leng with its Mediterranean airs and absurdly scholastic customs existed. He had held her as his wife and lover for nearly two decades-subjective, dwelt there and followed their ways as an honored noble guest for more than ten of those years: he could smell the hot, damp summer evening breeze in his nostrils, the scent of the climbing blue rose vines on the trellis behind his house —

The first time he gave the Library his home address and the identities to search for, it took him to a set of war grave records in the Autonomous Directorate, two years before his first interview with Xiri. He was unamused to note the names of his father- and mother-in-law inscribed in the list of terrorist wreckers and resisters who had been liquidated by the Truth Police in the wake of the liberation of Leng by Directorate forces.