The same console that allowed them to control the analytic instruments provided access to a star map. When Parantham activated it, it opened with a view showing their own path and present location (labeled with a stylized picture of the habitat's ring), along with several hundred billion kilometers of the meteor's trajectory before capture (labeled just as clearly with an image of the rock). In fact, the meteor had barely been «captured» — it looked as if the habitat had been constructed around it, more or less matching its original velocity — but the map was careful to delineate between the undisturbed object and its present state.
The map labeled the stars of the region solely by their physical characteristics, and despite phrasing this information in Rakesh's language, declined to adopt the catalog numbers or coordinate system that he would normally have used. Nevertheless, by invoking the library he could match the Aloof's descriptions with his own sources. The Amalgam's maps of the bulge were somewhat patchy, but there was more than enough overlapping data to establish a reliable fit.
For the first time, now, they knew exactly where they were. They had traveled some thirteen thousand light years from Massa, and while part of that journey had taken them «west» — clockwise around the galaxy, looking down from galactic north — they had also penetrated deep into the bulge, and had ended up less than a thousand light years from the galactic center. Lahl had reached roughly the same conclusions, though she hadn't been carrying star maps of her own to compare with the Aloof's.
This central region was distinctly more crowded and violent than the outer reaches of the bulge. Packed with massive gas clouds that periodically burst into life with episodes of star formation, as well as a varied population of older stars that had drifted in from the rest of the bulge, it was as different from the galactic disk as a teeming metropolis was from a rural backwater.
Rakesh said, «Where do you think Csi and the gang are now?»
«Dead to us,» Parantham replied bluntly. «And dead to each other as well.»
«I was inviting light-hearted speculation,» Rakesh said dryly, «not baleful philosophical pronouncements.»
«Then I'm sure they're having a wonderful time somewhere, sailing the high seas together.»
It was true that they were unlikely to have much in common any more; they were not part of a synchronization clan, they had made no appointment for a reunion. They had probably spent most of the past twenty-five thousand years as insentient data traveling through the Amalgam's network, but even if by some extraordinary coincidence they had crossed paths again, the chances were that their various measures of the time that had passed would have been millennia apart, placing the memories of their shared experiences into very different perspectives.
«So long as they're not still stuck at the node, then I'm happy,» Rakesh declared.
He shifted his attention back to the map — constructed inside his skull, but shared with Parantham — which pooled data from the Aloof and the Amalgam and annotated it according to the explorers' own priorities. It was easy to rule out all the stars that were younger than the rock itself; after that, the next obvious step was to try to account for the direction in which the rock was traveling.
The Aloof's map provided current velocities for the stars in the region — and like the stars' positions, these would have to be theoretical extrapolations from the latest data that could reach them at light speed — but it offered no past trajectories, either observed or computed. Rakesh wondered if this omission was a kind of strategic self-censorship; perhaps the Aloof considered that revealing just how long they'd been tracking these stars would grant some insight into the history of their civilization that they did not wish to disclose to outsiders. It could hardly have escaped their notice that the information would have been useful to their guests.
«Do they want us to find this planet, or not?» he muttered.
Parantham was undaunted. «They've had this meteor for at least fifty thousand years now. If their priority was making things easy for us, they could have located the planet themselves long ago, and sent us straight to it the moment we arrived. But that's not the deal. We're going to have to work for this. We knew that.»
The best dynamical model in the library couldn't wind back time fifty million years without generating uncertainties many times greater than the average distance between stars. Lahl had mentioned six hundred candidate stars; Rakesh couldn't whittle this down to less than five hundred with celestial mechanics alone.
Factoring in the chemistry of the rock made a difference. The Aloof's map included high-resolution spectra of each star, revealing the chemical composition of its outer layers precisely. Using a model of planetary-system formation it was possible to compute the probability of the rock's parent world being born from the same nebula as any given star. This reasoning was subject to its own uncertainties; nevertheless, the results allowed them to eliminate more than three hundred of their original candidates, and re-rank the two hundred that remained.
Before Rakesh could invoke any kind of high-powered statistical analysis, Parantham said, «That can't be right.» The chemistry-based ranking was not at all what might have been expected, with some candidates shuffled slightly down the list while others were promoted a few places. Rather, the second list more or less turned the first one on its head. The chemical profile of the region's stars placed the rock's origins in a completely different direction than that from which it seemed to have come.
«It must have undergone a sharp course change,» Rakesh suggested, «maybe even passing through another planetary system on its way.»
«Either that, or its chemistry's distorted for some reason,» Parantham said.
«So which trail do we follow?»
«Both, I suppose.»
Rakesh groaned. «So instead of halving our short list, we've just doubled it?»
Parantham said, «We haven't finished yet.»
«Of course not. I'm sure we can add another thousand candidates if we keep trying.»
Parantham selected close-up views of one star after another, but the Aloof's map displayed no planets around any of them. The data simply wasn't included, as if mere balls of rock were as irrelevant here as an anthill on a roadmap. Rakesh hadn't seriously expected to find the parent world in all its glory, teeming with long-lost DNA cousins, just by sitting here and zooming in on a map of the bulge, but a little more detail might have helped. The Amalgam's maps showed what was known, given the constraints, but if any world within the bulge had screamed «life» loudly enough for an observatory out in the disk to detect it, that would have been old news.
The gene fragments they'd found in the rock gave some tantalizing hints of the kind of proof-of-metabolism signature that the parent world's atmosphere might contain, though as ever there were uncertainties; these rock-dwelling microbes didn't have to be typical, let alone dominant on the planet as a whole, fifty million years later.
Rakesh said, «We need to make direct observations of our own.» The workshop had facilities that would allow them to construct a reasonably powerful telescope, but they lacked the raw materials to make anything big enough to analyze a planetary atmosphere from hundreds or thousands of light years away. They would need to travel further; they had no choice.
The console's main menu did not include any category for travel. It occurred to Rakesh that Lahl had never explained to them precisely how she'd got the message through to her hosts that she'd spent as much time as she could with the meteor, and wanted to move on.
After exploring every option pertaining to the habitat itself — including the ability to remodel the bathroom on command — Parantham finally realized that selecting a star on the map enabled a sub-menu with the unassuming option «Go to star». Choosing this did not change the map's viewpoint or magnification; rather, it caused the map to inquire politely, «Are you sure you wish to travel to this star?»
Rakesh said, «No, we're not sure yet, but thank you for asking.»
Parantham said, «Travel how? By what method? How long will it take?» The map remained silent. She re-invoked the option and the map asked again if she was sure, but it remained unresponsive to her requests for details.
Rakesh said, «Try some more stars, see if the option's always present.» They worked their way through a hundred candidates. In every case, the map claimed to be able to take them there.
«Does this mean they're all on the network?» Parantham wondered. The eavesdroppers out in the disk had only succeeded in mapping a small part of the Aloof's network, near the edge of the bulge. The nodes there weren't closely aligned with particular stars, but the known ones were certainly spread more thinly than the stars themselves. If the Aloof really did have receivers at all of the places where the map said it could take them, then either this was the best-connected region in the galaxy, or they had receivers at every single star in the bulge, period.
Rakesh said, «I doubt it. More likely they've just automated the ability to add new nodes.» Out in the disk, getting a receiver built at a new location was a major endeavor. First, you needed permission from the custodians of the local material resources. Then you had to organize the logistics of sending spores to construct the receiver itself. The technology had been streamlined over the millennia — with the need for eavesdroppers to chase the spillage of the Aloof's data around the inner disk providing a substantial boost — but it still wasn't something you did casually, just by pointing at an obscure star on a map and leaving the rest to insentient software.
Parantham said, «I've often wondered if the network we've mapped isn't merely a kind of decoy, which they built to make us think we understood them better than we really do.»
«You mean, not at all?»
«We've been telling ourselves that they use the same general communications technology as we do. Gamma rays modulated with data packets. Encryption keys separately distributed. All very cozy and familiar, as if it were the only conceivable way.»
Rakesh couldn't argue with her skepticism. Convergent technology was one thing, but in the Age of Exploration travelers had been amazed by the myriad ways other civilizations had found to solve identical problems, at least as often as they'd been startled to find their own culture's inventions eerily mirrored. «You think they were the ones who eavesdropped on
our
network first, and then they decided to build an imitation of it, as a sop to our curiosity?»
«As a sop to our curiosity. As a honey pot to lure us in. I don't know about their motives. But it wouldn't surprise me if all the 'traffic' we've been seeing over the last three hundred millennia has just been gibberish, and the Aloof's real highways are completely invisible to us.»
Rakesh said, «I don't know if that's good news or bad. Do you think they're going to let us ride the real highway?» He was past the point of feeling vulnerable, but he couldn't decide if it was somehow demeaning, or simply exhilarating, to imagine being whisked across the light years by a process he didn't even understand.
Parantham summoned up the first of their candidates on the chemistry-based list, a main-sequence star about four billion years old, two hundred and seventy-nine light years away. While it lay further from the crowded galactic center than their present location, the Amalgam's eye-view of it was still compromised by distance and obstacles. The presence of at least three gas giants had been deduced from the star's slight periodic motion, but no further details could be resolved from afar.
She said, «There's only one way to find out.»
8
Roi immersed herself in study, determined to reach the point where she could understand every detail of Zak's ideas. Excited as she was by the simplicity and grandeur of his vision, until she could test the fine points for herself she knew that her instinctive sense that he was on the right track needed to be treated with caution. Anyone could thump their carapace and invent a story so big that it seemed to swallow the world. The one thing that made Zak's account of weight and motion different was that anyone willing to make the effort could investigate the logic of his claims firsthand. On that, the whole thing would stand or fall.
Zak helped her to revise and extend her mathematical skills, starting with multiplication, then continuing all the way to something he called «template calculations»: manipulating abstract symbols as well as actual numbers, allowing her to perform a generic version of a sequence of computations without specifying all the quantities involved. After a while, it struck Roi that this was far more than a method for saving labor when she wished to repeat the same calculation many times on different sets of numbers. Just contemplating the template for the answer to a problem — without substituting any particular values for the symbols — could illuminate the relationship between all the quantities involved in a way that staring at endless lists of figures never would.
Zak was a patient teacher. Before she'd met him, Roi had thought of the unrecruited as pitiful creatures, lonely failures on the verge of death. Zak's time at the Null Line had certainly damaged his health, but in his own way he had worked far harder than anyone she'd ever known. Roi had rarely been so confident that the respect she felt for someone was deserved, and not just a product of the haze of camaraderie.
Between their lessons, Roi managed to extract some of his story. Like every hatchling, Zak had found tutors to provide him with a rudimentary education, but when the time came to join a work team, he'd drifted from one recruitment to the next. He'd felt the buzz of cooperation every time, but it had never been strong enough to hold him for long.
One shift, while working as a courier, he'd stumbled upon a library out in the sardside. The cargo he was carrying had had nothing to do with the place, but an accidental detour had been enough to capture his interest, and on the return leg of his journey he'd gone back for a closer look.