The Fleet of Stars

by Poul Anderson

  She seemed a little startled. "Ey, is it not the steepest of the gradients that drew you hither?''

  He shook his wraith-head. "Not exactly. It's one part of our overall need to know what the hell's gone on in the Solar System during all those centuries incommunicado. But, true, it does appear important. I do want to hear more about it."

  "You shall, you shall."

  "What say you explain the situation as you see it?" he proposed. "Never mind if you repeat what I've already heard. That can help put it in context for me, like scattered bricks getting picked up and mortared together to make a nouse."

  "Will you understand why that house bears the shape it does?"

  "I'll try. Uh, you needn't go into the theory, of course, nor the layout, unless it's changed since I got my briefing at Alpha Centauri." With electrophotonic speed, his mind reviewed them.

  Einstein first found it, in the mathematics of his general relativity: mass determines the metric of space-time, and thereby arises the phenomenon we call gravitation. This curves the trajectories not only of matter but of radiation. The confirmation was triumphant when astronomers measured a predicted slight displacement of stars in the field of view near the eclipsed sun. By the mid-twentieth century they were observing how galaxies act as enormous, irregular lenses to produce multiple images, distorted but enhanced, of objects far behind them. Not long afterward, they were detecting dark bodies within our own galaxy by the effects of these on the stellar background.

  But the sun is also a gravitational lens! Nearly spherical, it has little aberration. From this fact and certain calculations sprang a wonderful dream. The closest focal points are five hundred and fifty astronomical units outward, a fraction over three light-days—however, well within the Solar System. Let us send spacecraft there. We can do it by gravity assists, solar sails, magnetic sails. The journey will take about fifty years, but along the way the instruments will gather a rich harvest of data on solar wind, parallaxes, and who can foretell what else? Indeed, it should be worth going farther than the minimum distance, both to continue the secondary investigations and to gain added image size while reducing interference by the solar corona.

  Finally the craft will reach their destinations. The orbits they take up will be comparable to those of comets in the Kuiper Belt, although not necessarily in the same plane as any. The observatories will deploy their equipment to peer in the direction of the sun and on into the universe beyond, transmitting the data home to Earth.

  What knowledge they may win is incredible. Assuming the minimum distance or a trifle more, and a modest 12-meter antenna, the angular resolution at the 1,420-megahertz frequency of neutral hydrogen is on the order of several microarcseconds. Translated into spatial terms, this means that the observatory can resolve—distinguish from its surroundings—an object at Alpha Centauri as small as 1,250 kilometers across. At ten parsecs, 32.6 light-years, it can pick out 9,580-kildmeter sizes. Ten ki-loparsecs away, at the galactic nucleus, it can see something less than 10 million kilometers wide.

  This improves proportionately as frequency increases. At optical wavelengths, it could theoretically detect a human body near Alpha Centauri, a fifteen-kilometer asteroid or island near galactic center, individual continents on planets in the Andromeda galaxy.

  No one gave serious thought to such extravagances. They went beyond any feasibility, and perhaps beyond what natural law might allow. For a single example out of many, consider that the observatory is in orbit. Slowly though it moves, it is never at rest, and so neither is its line of sight. The farther it is looking, the fainter are the signals it receives, and the faster they sweep through its field of view—which becomes ever narrower as resolution increases. There will simply not be enough time to catch enough .photons to identify anything too small or too remote at frequencies too high.

  The dreamers would be satisfied with radio waves. Those were already opening fabulous vistas to them; the shape of the galaxy, the births and lives and deaths of stars, the titanic clouds and the ghost-winds between, pulsars and quasars and aliennesses untold—out to the rim of observable space and the dawn of observable time. To those among them who listened for word of sentience elsewhere, radio waves seemed most likely to bear it, someday, somehow. Send forth the observers whose instrument would be the sun!

  In particular, one that established itself in the sky—as seen from Earth—between the horns of the Bull, a little south of Elnath, would be on a line between Sol and the center of the galaxy. It would be looking at hordes of stars. We live in the outskirts, where they are thinning away into emptiness. The galactic heart is enormous. This observatory could scan it for a long time indeed before orbital motion, very slow at that distance from the sun, carried it out of the field. Surely its laser sendings back to Earth would tell of new marvel after marvel, maybe even, at last, signs of other minds than ours.

  Let the thing be done.

  In the event, it did not happen soon, nor all at once. The human space endeavor came near dying soon after it was born. Crewed missions grew scanty, and support was slight for a project whose time until fruition reached beyond the life expectancy of influential scientists. When Fireball Enterprises kindled fresh vitality, there was at first too much else to do. But later, Juliana Guthrie took up the idea. She had no difficulty in persuading her husband.

  By then, propulsion systems were available, efficient and economical, that enabled the craft to make their pas-· sages in years rather than decades. One did end in Taurus, near the star Elnath, about six hundred astronomical units out. Several others went into different sectors. And what they revealed was as enlightening as hoped for—

  —although never a clear trace of intelligence.

  Yes, they located planets of remote suns, far more than any optical system had done, and they carried out spectroscopic analyses with far higher precision. But the atmospheres they found that were in disequilibrium, let alone those that had free oxygen, could be counted on an astronomer's fingers. If life was this rare, humankind might well have the sole consciousness in the galaxy. Or in the universe?

  It did not discourage Guthrie. He was a stubborn sort. Yet it caused general interest to flag; and meanwhile, troubles came upon him and the world. When at last his download must lead his dissenters to Alpha Centauri, and Fireball dissolved, the lenses got no more attention.

  (This was, of course, a misnomer. Sol was the only lens. However, comparison of the gravitational observatories to the eyepieces of refracting telescopes had been inevitable.)

  They were made to require little maintenance, and infrequently, but now that little was denied them. The World Federation was preoccupied with urgent matters closer to home. The project was never formally terminated, but its resumption kept being postponed until it was well-nigh forgotten. Power sources ran down; radiation and quantum effects gnawed away. One by one, the lenses died.

  Sophotects came into being. As their intelligence grew, so did their underlying unity. The mesh of computers and effectors that pervaded civilization evolved into the cybercosm. Ever more, in its quiet fashion, it undertook scientific research, which ever fewer humans cared to do. This was not quite the paradox it appeared. Conventional wisdom held that science had reached its end point generations ago. The great equation from which every law of physics could be derived was in existence. Its solutions described the origin and ultimate fate of all that was, all that could ever be. True, not many of these solutions had actually been worked out, and of those that had, only rather special cases were fully comprehensible by mortals. Still, any observation that might be made would have a basic explanation; and the Teramind understood the grand design.

  Admittedly, more often than not, calculation was impossible. The principles of chaos and complexity took over. One could always find surprises in every field from archaeology to practical astronomy. Most humans had come to regard these as trivial, unworthy of a deep thinker. The cybercosm did not. It had the resources, including a kind of personal immo
rtality, to investigate the realm of the empirical.

  Eventually it proposed establishing a new set of solar lenses. The Synesis assented. People remembered that the destruction of Demeter was imminent; they heard rumors of contact between Proserpina and Centauri; suddenly the stars mattered to them again.

  Naturally, the task was entrusted to the cybercosm. Terrans had no reason to visit those abysses beyond Pluto. Weak flesh and fallible brains would merely get in the way of the work.

  Machines went forth. They demolished the old, dead observatories and replaced them with the new. These were immensely improved in sensitivity, spectral range, and every other capability. Each had its own powerplant, maintenance machines, and directing intelligence. That intelligence was dedicated, closely specialized— nevertheless, a conscious mind. Should any of the two-score assemblages in their widely canted orbits find treasure, more would follow.

  Data flowed afresh. Human scientists who eagerly studied the reports w«re not disappointed when they saw nothing fundamentally new. They had not expected it; the great equation did not allow for it. To map the dispersions of the galaxies, to limn the structures of those farthest away in space and time and thus to trace their evolution, to probe the reaches of our own and its sisters more deeply and fully than before: these achievements sufficed—

  —until the data stream began to sputter with anomalies, unaccountable, and dwindled to a trickle of routine follow-ups, and presently dried up altogether.

  On Earth, Luna, and Mars nearly everyone accepted the explanation that the cybercosm itself had no immediate explanation, and intellectual prudence required a halt in publication until the riddle was solved. The lenses would continue their searches and transmissions, but for the time being report only to other sophotects. Humans should not waste any of their all too short lifespans futilely fretting or puzzling over this. They had plenty of information to keep them busy, were they so inclined. People had grown used to trusting intellects superior to their own.

  Lunarians had not, nor had the Terrans beyond the Solar System; but only on Proserpina and its comet colonies were they near enough to feel rebellious. They got hold of everything the lenses had given to the databases—bit by bit, with considerable trouble through a lengthy stretch of time—and ransacked it over and over. As analysis proceeded, it pointed to the Elnath unit as the wellspring of the mystery. There the first inexplicable readings had been taken; there open communication first ended; there the instruments pointed toward the galactic nucleus, its crowding stars and veiling dust clouds, less known to this day than neighbor galaxies seen from outside.

  Always suspicious, the Selenarchs had never found it reasonable that the cybercosm would withhold observations simply because they were enigmatic. If the great equation proved in need of amendment, what harm in that? Or... what promise, which the Teramind did not want humans to know of, lest they become like it? The Selenarchs determined to find out for themselves.

  "What ken have you of our attempts to orbit a lens?" Luaine asked.

  "Not much," Guthrie admitted. "I've gathered that two different tries, decades apart, failed, and you Proserpinans claim it was due to sabotage. But was it?"

  "Why think you otherwise?"

  "Well, I do know something about how tough the job is and what it costs—resources and skilled man-years that have plenty of call on them elsewhere. To match the ones in existence, you have to push the very limits of the associated technologies. It was never possible at Alpha Centauri, what with three suns waltzing around twisting gravity fields and orbits. So far we've put just four out around Beta Hydri, using the original Fireball design because we weren't up to developing anything better. They've been useful, but they cover mighty small patches of sky, and they haven't done more than add details to what our other apparatuses show. Nobody's yet managed anything similar at Isis or Hestia, unless it's happened since last I heard from them."

  "Ai, yes," said Luaine impatiently. "But hear. Our first lens, which had been painstaking years in the making, was outbound when its carrier was wrecked, and it therewith. The cause seemed to be collision with a rock. How likely is that? Besides the sheer volume of yon spaces, torhave sufficient speed, the rock must have been a stray out of the interstellar deeps. Few like that have we ever noted, Guthrie."

  His Image-head nodded. He had heard this before from others. Let her talk, though. A Lunarian could want to get something off her chest, the same as a Terran.

  "In the second instance," she went on, "the lens took orbit as planned, well away from the Synesis' but aimed likewise at mid-galaxy. While undergoing its initial tests and calibrations, of a sudden it failed, ceased utterly to function. It must be brought back, at high cost in time and fuel, for examination."

  There would have been no sophotects on the spot to do that, Guthrie reflected; the Proserpinans refused to have any capable enough. A manned lab in the vicinity would have been too expensive. Antimatter for engines was quite a bottleneck when you lacked access to the facilities on Mercury and must produce the stuff with thermonuclear reactors. Luaine had really had to work and connive to get Dagny supplied.

  "They found that a defective interfacing, miscrystal-lized, had led to derangement of the programming matrix," she said. "How could such a piece have passed every beforehand inspection? But a robotic device, closing in on the assembly while it fared goalward, and applying a minute amount of energy so—" She snapped thumb and forefinger together, a savage, scissoring gesture.

  "I've heard this," he replied. "Also that you decided not to try again, for a while, anyhow. You think the cybercosm's got you under too close a surveillance?" ·

  "Eyach, its minimachines cannot be everywhere, nor scan everything," she said: due to limitations of size, speed, communication, and related factors. "Intermittent spying at a few key points is amply bad."

  Lunarians wouldn't go in for tight security, Guthrie thought. Too restrictive of them. "Well, I've considered that sort of possibility, even for us way out at our suns. It's one of the reasons I came here. But let's get on with the story. I've heard only a little about the rest of it."

  "This day watch I shall tell you. It became chiefly the venture of the Captains of the Outer Comets."

  "You planned a frontal attack, to try and find out directly what the secret is."

  "Yes. We prepared for years, with utmost care against spies. We knew we would have but the single opportunity. Thereafter the enemy would be fully alert."

  While Guthrie had his own reservations about Synesis and cybercosm, it troubled him to hear her say "enemy." But never mind for now. "You meant to strike at the lens you felt sure would hold the information."

  "Yes. The Orion lens." Seen from Proserpina, the watcher of the galactic nucleus was not in Taurus.

  "Uh-huh. And your expedition found the cybercosm had anticipated you and the target was well defended."

  Luaine arched her back like an angry cat. "Raiach!" Her features congealed in self-possession. "I will show you."

  Somehow she produced a datacard from her skin-snug garment. Deft as a hawk, she swooped to place it in the multiceiver. The screen went black and starry.

  A lean shape swam into sight, a field-drive speedster seen from a distance. "Our ship," Luaine explained. Her words came flat, metallic. "The crew released several self-propelled cameras, which transmitted back to them. This is a compilation."

  The view moved around to the solar lens. Guthrie had studied the plans, which were published when the system was authorized. Nonetheless, his gaze raked what he saw. Faerie beauty, an intricate, silvery-gleaming spiderweb of antennae and cables, ringed and dwarfed a golden-hued spheroid that housed the maintenance machines, attitude controls, and powerplant. From it swelled a bubble, opalescent in the star-sheen, a dome protecting the observatory proper. He could just make out an access port at its base.

  Three sparks left the ship and drifted across the constellations toward the lens. A camera zoomed in on them and magnified. From small bodie
s sprang arrays of sensors and effectors. "Robots," sounded Luaine's toneless voice. "They were redundantly versatile and well-programmed; entry and readout should be simple for them. But we wanted full preparation against contingencies. The crew stayed in direct communication, with override controls."

  The robots drew nearer their quarry. Guthrie deemed it was about time for them to reactivate their jets and start approach maneuvers. They did not. Abruptly inert, they drifted on past the web and vanished into darkness.

  Consternation resounded on the audio. Luaine tuned it down. "The robots ceased to function," she said, still like another machine. ' They no longer responded to signals or commands. Instruments aboard ship registered electromagnetic pulses, with a high intensity in the region they were crossing when the failure occurred."

  Guthrie had expected that conclusion. "Yeah. The station's sophotect ordered the output, heterodyned so as to be at max exactly there. Induced currents and magnetic transients, powerful enough to act through metal and scramble the electronics and electrophotonics inside, disabling anything that depended on those circuits—which would be just about everything. Your boys ought to be thankful they didn't bring their ship any closer, though I doubt they felt that way."

  "They had been cautious. A few minutes afterward—" Luaine raised audio volume again.

  The radio voice that the Proserpinans had received and recorded rang in their own language, cool, a sexless tenor, obviously synthesized. "Attention. You have attempted a criminal act and seen its immediate consequences. This was no reaction to a surprise. Your vessel was detected and trailed almost from its departure point. You were allowed to come this far that the unattainability of your ambition might be demonstrated to you. If you return at once, the Synesis will regard your vain expenditure as an adequate punishment. Otherwise, armed guardian craft will arrive very shortly and destroy you. Best you go home and warn your co-conspirators to desist."