Existence

Meanwhile, please stop meddling in things you don’t understand.

82.

MELANCHOLY LANES

The chert-core gleamed under Tor’s headlamp as she turned it in her prosthetic hand, holding the relic up close to a stretch of carved and polished asteroidal stone-the wall that was her greatest discovery. Those chiseled lines and figures were her fame. All else would fade, in comparison. Yet, it was the fist-size rock from Earth-rounded and fluted from the labor of mesolithic toolmakers-that held her contemplation.

Is this why I brought you along, half a billion klicks from home? To represent the dim ages of my ancestors? To somehow illuminate this dark place?

The last hands that hewed and chipped at the core were those of cave-dwellers, who saw mere god-twinkles when they looked up at the stars. But they did look up. And thus began a journey that led here…

… back underground again. Trading torchlight for laserbulbs to view cavern art. Lower gravity. No air. And this cave last heard voices sixty million years ago. Yet, still.

She held the stone age specimen close to a portion of the message-wall, depicting scenes of devastation. One of the deep-carved cavities seemed almost a perfect fit. It was uncanny.

On impulse, Tor slid the ancient tool-core into a niche in the far more ancient wall. It stayed there, right at home, now surrounded by incised figures and rays. Now part of a prehistoric tale of battle and woe, enduring brutal assault by forces of relentless belligerence.

I miss my old smart-mob, she thought, pondering her handiwork-her small addition to panel twelve of row four of the Great Chronicle. They would have been pouring forth correlations and tentative translations by now. A posthuman intelligence made up of ten thousand merely very smart individual human beings… and their ais and tools.

Ah, but hadn’t that been one of her reasons for leaving Earth? Denied the pleasures of flesh-of family and warm lovers-she had become the heart of a mob-entity, its driving spirit, its mother… one of the top twenty out of eighty thousand citizen posses that prowled the New Earth Civilization like organic T cells, sniffing for crimes, conspiracies, or errors to unveil…

It was my work, important work, and it consumed me. All the other members-except the auties- had regular lives to return to. They took turns. But I was always on call, with nothing for distraction. In the end, it was depart or die. Move on to a new phase. A new adventure.

Now?

She and Gavin had made certain to beam a full scan of the wall to Earth, first thing, in case another FACR chose to intervene. Was this the reason for that earlier attack? In order to stop humanity from viewing the chronicle? If so, victory was now complete. The message-the warning-inscribed by little hands so long ago, was on its way.

But there won’t be any flash answers from back home. Not for hours, even days. For a little while, this is ours. And ours alone. A mystery, in the old, exciting and terrifying sense.

* * *

Tor had started out viewing the ancient colonists as unsophisticated. How could folk be capable if brewed in test tubes, decanted out of womb tanks, and raised by machines? Baked, modified, and prepared for a planet’s surface, they depended on the mammoth star mother for everything. Might as well view them as fetuses.

Yet clearly, they knew what was going on. And when lethal failure loomed, the creatures figured out a way to preserve one thing. For their story to be read long after all magnetic, optical, or superconducting records decayed. The biologicals found their enduring medium-in a wall of chiseled stone.

“Interpreting the writing will take experts and argument. We can only guess,” Gavin told her as he used a gas jet to blow dust from uneven rows of angular letters. “But with these pictograms to accompany the text, it might just be possible.”

Gavin’s voice was hushed, still adjusting to what they found here. A Rosetta Stone for an entire alien race? Maybe bunches of them.

“You could be right,” Tor commented. The little robot she had been supervising finished a multifrequency radar scan of the southern wall-checking for more layers behind the surface-and then rolled to one side, awaiting further instructions. Tor hopped up to sit cross-legged on another drone, which hummed beneath her patiently. In the feeble gravity Tor’s arms hung before her, like frames encompassing a picture-puzzle.

The creatures must have had time, while battles raged outside their catacombs, for the carvings were extensive, intricate, arrayed in neat rows and columns. Separated by narrow lines of peculiar chiseled text were depictions of suns, planets, and great machines.

And more machines. Above all, pictographs of mighty mechanisms covered the wall.

The first sequence appeared to begin at the lower left, where a two-dimensional starprobe could be seen entering a solar system-presumably this one-its planets’ orbits sketched in thin lines. Next to that initial frame was a portrayal of the same probe, taking hold of a likely planetoid, mining and manufacturing parts, preparing to make self-replicas.

Eight copies departed the system in the following frame. There were four symbols below the set of stylized child probes… Tor could read what must be the binary symbol for eight, and there were eight dots, as well. It didn’t take much imagination to tell that the remaining two symbols also stood for the same numeral.

The wall was meant for self-teaching how to read the rest. They weren’t dopes.

So, translation had begun. Apparently this type of probe was programmed to make eight copies of itself, and no more. It settled a nagging question that had bothered Tor for years. If sophisticated self-replicating probes had been roaming the galaxy for eons, why was there any dead matter left at all? In theory, an advanced enough technology might dismantle not only asteroids but planets and stars. If replicant probes had been simplemindedly voracious, they might gobble the whole galaxy! There’d be nothing left but clouds of uncountable starprobes… preying on each other till the pathological system fell into entropy death.

That fate had been avoided. This Mother Probe showed how. It was programmed to make only a strictly limited number of copies. This type of probe was so programmed, Tor reminded herself.

In the final frame of the first sequence, after the daughter probes had been dispatched to their destinations, the mothership was shown moving next to a round globe-a planet. A thin line linked probe and planet. A vaguely humanoid figure, resembling in caricature the mummies on the floor, stepped across the bridge to its new home.

The first story ended there. Perhaps this was a depiction of the way things were supposed to go. An ideal. Or the way it went for the probe’s own parent, an eon earlier.

But there were other sequences. Other versions of reality. In several, the Mother Probe arrived at this solar system to find others already here. Tor realized that one of these other depictions must represent what really happened, so long ago. But which one? She breathed shallowly while tracing out the next tale, where the Mother Probe arrived to meet predecessors… and all those earlier ones had little circular symbols next to them.

In this case everything proceeded as before. The Mother Probe made and cast out its replicas, and went on to seed a planet with duplicates of the ancient race that had sent out the first version, long ago.

“The little circle means those other probes are benign,” Tor muttered to herself.

Gavin stepped back and looked at the scene she pointed to. “What, the little symbol beside these machines?”

“It represents types that won’t interfere with this probe’s mission.”

Gavin was thoughtful for a moment. Then he reached out and touched a different row. “Then this crosslike symbol…?” He paused, examining the scene, and answered his own question. “It stands for types that would