Tides of Light

by Gregory Benford

  Something akin to hunger stirred in the cold bar.

  Its sail, mirrored by countless mica-thin cells, reflected the distant star’s glow onto the prey. This patient lance of sunlight blew away a fog of sublimed ice. The beast tugged at its shrouds to avoid being thrust askew by the gas, but kept the precise focus.

  A shaft deepened. At random spots inside, residual radioactivity had melted the water ice, forming small pockets of liquid. The seedbeast extended down a hollow tendril.

  The first suck of delicious liquid into the reed-thin stalk brought to the seedbeast a heady joy—if a conglomerate of reproducing but insensate cells can know so complex a response.

  More tendrils bridged the gap. They moored the beast to the iceball and provided ribbed support for further growth of the sail. The glinting, silvery foil sent lancing sunlight into the bore-hole, exploding the chemical wealth into fog.

  Food! Riches! Many centuries of waiting were rewarded.

  Thin, transparent films captured the billowing gas. Eager cells absorbed it. Nutrients flowed out to the seedbeast’s core body. Spring came after a winter unimaginably long.

  Finally the conical hole was deep enough into the ice to ensure protection from meteorites and even most cosmic rays. The bar tugged at new contractile fibers. Its nest was safely bored. Gingerly, it migrated. Care informed every move. Painfully tentative tugs at its contractile strands brought the dense, dark axial bar safely down into the pit. Here it would reside forever.

  The descent of the central axis, now swelling enormously, inaugurated fresh responses. The beast grew crusty nodules that sprouted into pale, slender roots. Deep molecular configurations came into play. Though it had nothing resembling true intention, the beast began preparing for its next great adventure: the fall sunward.

  No intelligence guided it yet. The rough bark and dark browns of the body sheltered complex genetic blueprints, but no mind.

  Roots poked and pried through the ice. Complex membranes wriggled, the waste heat of their exploring melting a path. Then they sucked out the thin liquid—building more tissue, forcing open crevices. A fraction of the slow wealth worked back to the central body, where more minute blueprints unrolled in their molecular majesty.

  Mining roots sought rare elements to build more complex structures. Ever-larger sails grew. The iceball that might have become a mere comet felt patient, cautious probings. The beast could take unhurried care, lest it find some unexpected danger.

  Fans of emerald green crept over the grimy surface ice. In a century the tumbling ice mountain resembled a barnacled ship, overgrown with mottled, crusty plants that knew no constraint of gravity. Sap flowed easily in wide cellulose channels. Contractions brought warming fluid to stalks that fell into shadow.

  This spreading, leathery forest occasionally heaved and rocked with sluggish energy. It extended great trunks high into the blackness above. Trees of thick brown butted against one another in competition for the sun. Leaves sprouted, wrinkled and lime green.

  Only the ever-swelling sails could stop the woody spears’ outward thrust. When a trunk shadowed the sails, a signal worked its way down through the tendrils. In the offending tree sap ebbed, growth stopped.

  The trunks were not simply made. Inside the ice, mining roots sought lodes of carbon. Though the plants above displayed impossibly ornate convolutions and flowerings, this was a minor curlicue compared with the sophisticated complexity that went on at the molecular level of the mining roots.

  They harvested carbon atoms and towed them into exact alignment, forming its crystal: graphite. Slight imperfections in the match were negotiated by a jostling crowd of donor or acceptor molecules. Great graphite fibers grew with cautious deliberation, flawlessly smooth.

  Countless other laboring molecules ferried the graphite strands beneath the tree bark. Years passed as they merged, providing structural support far beyond what the gravity-free plant needed. The fibers waited in reserve, for the overgrown ice world was steadily swinging inward, toward the sun.

  By now the forest had swelled to many times the size of the parent iceball. The star ahead was no longer merely a fierce point of light. Millennia of tacking in the soft breath of photons had brought the comet-beast within range of the planets.

  The pace quickened aboard. Small, spindly creatures appeared, concocted from freshly activated genetic blueprints. They scampered among the foliage, performing myriad tasks of construction and repair.

  Some resembled vacuumproof spiders, clambering across great leathery leaves with sticky-padded feet. They could find errors in growth, or damage from piercing meteoroids, beneath the pale light of the distant sun. Following instructions carried in only a few thousand cells, these black-carapaced beasts poked thin fingers into problems.

  If a puzzle arose beyond their intricately programmed routines, they found the nearest of the coppery seams that laced around the great trunks. These were superconducting threads. Making contact, the spiders could communicate crudely but without signal loss to the core-beast.

  Electrical energy also flowed through the threads steadily, charging the spiders’ internal capacitors and batteries. Though biologically hardwired for their tasks, the spiders could receive and store more complex instructions for temporary problems. The greater core-beast was simply a larger example of such methods; complex and resourceful, it was nonetheless not yet an autonomous intelligence.

  The moment came for more powerful maneuvers. This registered in the core-beast and brought forth a response that a witness might have found to be evidence of high originality. Silicates began to collect on the one surface spot left bare by the plants. Spiders and crusty fungus together fashioned ceramic nozzles and tanks, linked by clay-lined tubing. Carefully hoarded oxygen and hydrogen combined in the combustion chamber. An electrolytic spark began a steady contained explosion. The comet-beast moved sunward again.

  Still, its destination was not the fiery inner realm. Its hoard of ice would have sublimed there, disemboweling the beast. The sun could never be a close friend.

  Instead, it followed a gradual inward spiral. In time the heat generated in the crude rocket engine threatened to warm the comet too much. When melting began, the beast switched to smaller pulpy bulbs, grown like parasitic sacs far up the towering trees. These combined hydrogen peroxide and the enzyme catalase, venting their caustic steam safely away from the precious ice reserve.

  It pursued a particularly rich asteroid which the solar mirrors had picked out. Cellulose bags grew near the photoreceptors and filled with water. These thick lenses gave sharp images which the comet-beast used to dock itself adroitly alongside its newest prey.

  Breaking up the tumbling, carbon-rich mountain took more than a century of unflagging labor. Larger spiders came forth, summoned by deeper instructions. They ripped minerals from the asteroid with jackhammer ferocity. Crawling mites urged on the slow, steady manufacture of immense graphite threads.

  From silvery silicates the myriad spider swarms made a reflecting screen. Swung on contractile fibers, this fended off the occasional solar storms of high-energy protons that came sleeting into the comet-forest. The beast continued to spiral inward. Protecting the more delicate growths and preventing ice losses became its primary concern.

  The beast grew now by combination. Graphite threads entwined with living tissue along a single axis. What had begun as a thin bar now replicated that form on a huge scale.

  The skinny, iron-gray thing grew slowly as meticulous spiders helped the weaving. Gradually the asteroid dwindled. The bar became immense. It was thickest at its middle, where the core-beast now lived inside. Even cosmic rays could not reach through the protective ice and iron to damage the genetic master code.

  Then chemical vapors poured again from low-thrust ceramic chambers. And a new trick was turned: electromagnetic drive. Induction coils surged with currents, propelling iron slugs out through a barrel. This mass-driver shed matter that the beast did not need, banging away like a sluggish mach
ine gun.

  The assembly began another voyage, this one much less costly in energy. Still, it needed many orbits to complete the efficient loop to the next asteroid.

  Centuries passed as the ever-lengthening bar consumed more of the stony little worlds. Solar furnaces made of the silvery reflecting films smelted, alloyed, and vacuum-formed exotic, strong girders for the bar. But the central art was the incessant spooling out of graphite threads to join those already lying along the great bar.

  Many thousands of years passed before the final stage in the great beast’s growth to maturity began. The last, most complex gene sites deep within the original biological substrate began to replicate themselves.

  Intelligence is, finally, in the eye of the beholder. The actions which followed would have seemed to observers to be obvious evidence of problem-solving and creativity on a scale, and at such speed, as to completely prove the guidance of a considerable mind.

  Perhaps the cells that directed the vast bar-beast still farther sunward were, by now, a mind. Here distinctions turn on definitions, not data.

  The beast had decided on its final destination long before: a planet with abundant liquid water.

  The beast was immensely long by now, grown to a third of the target planet’s radius. To the eye of an inhabitant of the planet, though, it was very nearly invisible—because the vast brown-black construction was only slightly thicker than the original comet-beast. Indeed, a dab of ice still clung to the exact center of the immense cable. Caution dictated that the beast always have a reserve.

  Still, as the planet swelled from a dot to a disk, more mirrors deployed behind it—a precaution against defense by possible inhabitants. None rose to meet the beast. Mechs had not yet come to the world, and the lesser life which dwelled there probably did not give even passing attention to the slim, dark line in the night sky.

  Still, a few small asteroids did pass momentarily across the face of the planet. Ever cautious, the beast focused its great mirrors. The offending motes fused into slag.

  The beast always erred on the side of prudence. Still, its greatest risk now yawned.

  With grave deliberation, mass-drivers began to fire all along its length. They slowly flung away the last reserves of useless slag, subtracting orbital angular momentum. This planet did not have a moon, so the beast could not undergo repeated flyby encounters to lose its momentum. Instead, decades of careful navigation brought it closer to the world.

  The grand moment came at last. The nub end of the bar-beast swept up the first atoms of the atmosphere. This sent complex signals through the superconducting threads that wrapped the bar. Something like elation triggered more rapid molecular transitions.

  It tasted the tenuous air. This was wealth of a new sort: mild gases, water vapor, ozone. Especially broad leaves captured minute amounts and pooled them in great veins. Samples reached the core-beast and were judged good.

  The land below lay ripe with life. This was the longordained paradise the beast sought. Now it began on the full task of its maturity.

  The great bar began to spin.

  *As you witness,* the Tukar’ramin interrupted Quath’s meditation, *the Illuminates know much of such objects.*

  Quath had absorbed the yawning history of the beast in a glimmering fragment of a moment, faster than an eyeblink. The massive thing still plunged down the sky, framed against the glow of the revolving Cosmic Circle.

 

  *No, the Circle orbits much farther out. Your signal carries overcurrents of alarm, Quath. Why?*

 

  *Fear?*

 

  *Do not concern yourself. This object was here when we came. The mechs had made no use of this odd, rotating thing. Perhaps they did not realize that it is alive—else they would have killed it.*

 

  *This self-replicating form spreads naturally among the stars of Galactic Center. We do not know its origins.*

 

  *None that we can see. What does brute life know of purpose, Quath?*

 

  *This presumably does so. They have been seen near other planets. We have not taken the time to study them in detail.*

 

  *Surely you err.* The Tukar’ramin’s tone was suddenly cool.

  Quath said diplomatically,

  *Do not neglect the Illuminates,* the Tukar’ramin said formally.

 

  Their conversation had proceeded through several microseconds as Quath peered upward in awe.

  *Not at all,* the Tukar’ramin said condescendingly. *Such structures are a minor element in the greater equation of this world. I have news for you—*

 

  A torrent of emotion burst upon Quath. The terror and wonder she had felt so much lately now swelled to become a toppling wave, drowning her in sudden, wrenching currents. She felt, at last, what separated her from all the rest of the podia. Awe—simple and yet unendurably vast. It swept through her, cleansing and divine.

  *Come, Quath, pay attention. There is grave, deep division between the Illuminates. Some Illuminates have seized podia here.*

  Quath repeated this timeworn homily while her overmind swirled with smoldering, long-suppressed impulses.

  The Tukar’ramin’s acousto-magnetic profile took on tints and flavors Quath had never felt before. *There is holy conflict. Even the Illuminates are divided, and struggle against one another.*

  Mordant hues conveyed the gravity of this revelation.

  *I do not understand what is happening. Some of the podia of our own Hive do not respond to my commands. They are carrying out purposes I do not know.*

  Quath said sharply,

  *Some of the Illuminates feel we should not pursue this aim, should not venture toward Galactic Center as yet. Certainly, they say, we should not do so using the unreliable knowledge gained from a lowly Nought craft.*

 

  *Yes, I gather so.* Sadness and disbelief resonated through the Tukar’ramin’s rich spectrum.

 

  *Many, and everywhere.*

 

  *That we do not have. Find it! But beware others of your Hive—they act now for agencies I do not fathom.*

  Quath said sternly.

  But her bravado was a cover for her own churning inner world. She stared upward at the massive presence and murmured to herself,

  The fragile air filled with glorious notes.

  NINE

  Killeen woke in a puffy languor. He rolled over and found himself beside Shibo. She snuggled spoon fashion against him and he let the moment of lazy pleasure take him. It was a while before the restive minds of his Aspects nibbled at his sweet indolence, bringing forward the questions which he had put aside the night before.

  The seed-fruit, that was it. Its aromatic wealth had swarmed up into him, canceling all the vexing voices, smothering his long-trained instincts of vigilance and nervous caution.

  Partway through the celebration Shibo had
said to him, “Good for you. For us all.” When he had only mildly agreed, she had laughed merrily and pushed his face down into a moist husk of seed-fruit.

  The rogue banquet had spun on for hours. The fruit baked and fumed over the Families’ fires. Songs had rolled over the mountainside. Spontaneous, mournful dirges for the newfallen dead had risen from the firesides. The chants roiled with rage and then swerved into bursts of bawdy energy. As the bountiful seed-fruit had its effects, the songs turned to soft, low ballads of the oldtimes. These Families had their former great ages, their sites made sacred by work and sacrifice, their Citadels and lush fields now lost and smashed. Yet they carried on singing into the teeth of fresh defeats.

  There had been alcohol, too. The precious small flasks that some carried were much like those the Families of Snowglade had so lovingly fashioned and ornamented. Killeen had made himself pass the fruit-flavored brandy each time it came by him, even though his mouth watered at the heady smell of it. That way lay a steep slope.

  His Supremacy had gathered the Families finally, as the general celebration-and-wake subsided into addled fatigue and drunkenness. Killeen had half-listened to the man’s shouted words, hoping they would explain what had happened this night. His Supremacy spoke of the Skysower, and such it was: The seeds came down on each descent.

  Religious jargon obscured His Supremacy’s rhythmic incantations. Rolling phrases described the Skysower as the source of humanity’s connection to all natural forces. The Tribe felt itself somehow part of Skysower’s life cycle. The small but commanding man spoke of returning the bountiful gifts with the ripeness of the infinitely fertile soil. The signature of life was its webbed unions, threading All into One. There was much loud, vague talk of the Skysower as the Tribe’s living link to the time of the Chandeliers, as God’s sovereign messenger, as the one living being no mech could destroy. Eating its seeds was a religious act, a holy communion with the high sources of life’s dominion.

  “The blood and body of vaster realms was here delivered unto us,” His Supremacy had yelled, his eyes rolling and face streaming with glistening sweat. “Take! Eat! And prepare!—for tomorrow’ s march. For victories to come!”