The Best of Gregory Benford

by David G. Hartwell

  John proposed that he send in a robo-craft of bird size, to measure physical parameters in the heart of the gap. Captain Badquor approved. The shops fabricated a convincing fake. Jet-powered and featuring fake feathers, it was reasonably convincing.

  John flew escort in a rocket-plane. The bird-probe got seventeen kilometers inside and then disappeared in a dazzling blue-white electrical discharge. Telemetry showed why: the Circular Ocean’s support was a complex weave of electrical fields, supplying an upward pressure. These fields never exceeded the break-down level of a megavolt per meter, above which Shiva’s atmosphere would ionize. Field strength was about a million volts per meter.

  The robo-craft had hit a critical peak in the field geometry. A conductor, it caused a flashover that dumped millions of watts into the bird within a millisecond.

  As the cinder fell, John banked away from his monitoring position five kilometers beyond the gap perimeter. There was no particular reason to believe a discharge that deep within the gap would somehow spread, engulfing the region in a spontaneous discharge of the enormous stored energies. Surely whoever—no, whatever—had designed the Circular Ocean’s supports would not allow the electromagnetic struts to collapse from the frying of a mere bird.

  But something like that happened. The system responded.

  The burned brown husk of the pseudo-bird turned lazily as it fell and sparks jumped from it. These formed a thin orange discharge that fed on the energy coursing through the now-atomized bird. The discharging line snaked away, following unerringly the bird’s prior path. It raced at close to the speed of light back along the arc.

  The system had memory, John realized. He saw a tendril of light at the corner of his vision as he turned his flitter craft. He had time only to think that it was like a huge, fast finger jabbing at him. An apt analogy, though he had no time to consider ironies. The orange discharge touched the flitter. John’s hair stood on end as charge flooded into the interior.

  Ideally, electrons move to the outer skin of a conductor. But when antennae connect deep into the interior, circuits can close.

  Something had intended to dump an immense charge on the flitter, the origin of the pseudo bird. Onboard instruments momentarily reported a charge exceeding seventeen coulombs. By then John had, for all intents and purposes, ceased to exist as an organized bundle of electrical information.

  John’s death did yield a harvest of data. Soon enough Lissa saw the true function of the Circular Ocean. It was but an ornament, perhaps an artwork.

  Ozone fizzed all around it. Completely natural-seeming, the lake crowned a huge cavity that functioned like a steady, standing laser.

  The electrical fields both supported the Ocean and primed the atoms of the entire atmosphere they permeated. Upon stimulus—from the same system that had fried John—the entire gap could release the stored energy into an outgoing electromagnetic wave. It was an optical bolt, powerful and complex in structure—triggered by John.

  Twice more the ocean’s gap discharged naturally as the humans orbited Shiva. The flash lasted but a second, not enough to rob the entire ocean structure of its stability. The emission sizzled out through the atmosphere and off into space.

  Laser beams are tight, and this one gave away few of its secrets. The humans, viewing it from a wide angle, caught little of the complex structure and understood less.

  Puzzled, mourning John, they returned to a careful study of the Shiva surface. Morale was low. The captain felt that a dramatic gesture could lift their spirits. He would have to do it himself.

  To Captain Badquor fell the honor of the first landing. A show of bravery would overcome the crew’s confusions, surely. He would direct the complex exploring machines in real-time, up close.

  He left the landing craft fully suited up, impervious to the complex biochem mix of the atmosphere.

  The tiles jostled downhill from him. Only in the steep flanks of this equatorial mountain range did the tiles not endlessly surge. Badquor’s boots crunched on a dry, crusty soil. He took samples, sent them back by runner-robo.

  A warning signal from orbit: the tiles in his area seemed more agitated than usual. A reaction to his landing?

  The tile polygons were leathery, with no obvious way to sense him. No eyes or ears. They seemed to caress the ground lovingly, though Badquor knew that they tread upon big crabbed feet.

  He went forward cautiously. Below, the valley seemed alive with rippling turf, long waves sweeping to the horizon in the twinkling of an instant. He got an impression of incessant pace, of enthusiasm unspoken but plainly endless.

  His boots were well insulated thermally, but not electrically; thus, when his headphones crackled he thought he was receiving noise in his transmission lines. The dry sizzle began to make his skin tingle.

  Only when the frying noise rose and buried all other signals did he blink, alarmed. By then it was too late.

  Piezoelectric energy arises when mechanical stress massages rock. Pressure on an electrically neutral stone polarizes it at the lattice level by slightly separating the center of positive charge from the negative. The lattice moves, the shielding electron cloud does not. This happens whenever the rock crystal structure does not have a center of structural symmetry, and so occurs in nearly all bedrock.

  The effect was well known on Earth, though weak. Stressed strata sometimes discharged, sending glow discharges into the air. Such plays of light were now a standard precursor warning of earthquakes. But Earth was a mild case.

  Tides stressed the stony mantle of Shiva, driven by the eternal gravitational gavotte of both stars, A and B. Periodic alignments of the two stars stored enormous energy in the full body of the planet. Evolution favored life that could harness these electrical currents that rippled through the planetary crust. This, far more than the kilowatt per square meter of sunlight, drove the tile-forms.

  All this explanation came after the fact, and seemed obvious in retrospect. The piezoelectric energy source was naturally dispersed and easily harvested. A sizzle of electric microfields fed the tiles’ large, crusted footpads. After all, on Earth fish and eels routinely use electrical fields as both sensors and weapons.

  This highly organized ecology sensed Badquor’s intrusion immediately. To them, he probably had many of the signatures of power-parasite. These were small creatures like stick insects that Badquor himself had noticed after landing; they lived by stealing electrical charge from the tile polygons.

  Only later analysis made it clear what had happened. The interlinked commonality of piezo-driven life moved to expel the intruder by overpowering it—literally.

  Badquor probably had no inkling of how strange a fate he had met, for the several hundreds of amperes caused his muscles to seize up, his heart to freeze in a clamped frenzy, and his synapses to discharge in a last vision that burned into his eyes a vision of an incandescent rainbow.

  Lissa blinked. The spindly trees looked artificial but weren’t. Groves of them spiraled around hills, zigzagged up razor-backed ridges and shot down the flanks of denuded rock piles. Hostile terrain for any sort of tree that earthly biologists understood. The trees, she noted, had growing patterns that bore no discernible relation to water flow, sunlight exposure, or wind patterns.

  That was why Lissa went in to see. Her team of four had already sent the smart-eyes, rugged robots, and quasi-intelligent processors. Lightweight, patient, durable, these ambassadors had discovered little. Time for something a bit more interactive on the ground.

  That is, a person. Captain Badquor’s sacrifice had to mean something, and his death had strengthened his crew’s resolve.

  Lissa landed with electrically insulated boots. They now understood the piezoelectric ecology in broad outline, or thought they did. Courageous caution prevailed.

  The odd beanpole trees made no sense. Their gnarled branches followed a fractal pattern and had no leaves. Still, there was ample fossil evidence—gathered by automatic prospectors sent down earlier—that the bristly trees
had evolved from more traditional trees within the past few milllon years. But they had come so quickly into the geological record that Lissa suspected they were “driven” evolution—biological technology.

  She carefully pressed her instruments against the sleek black sides of the trees. Their surfaces seethed with electric currents, but none strong enough to be a danger.

  On Earth, the natural potential difference between the surface and the upper atmosphere provides a voltage drop of a hundred volts for each meter in height. A woman two meters tall could be at a significantly higher potential than her feet, especially if her feet had picked up extra electrons by walking across a thick carpet.

  On Shiva this effect was much larger. The trees, Lissa realized, were harvesting the large potentials available between Shiva’s rocky surface and the charged layers skating across the upper reaches of the atmosphere.

  The “trees” were part of yet another way to reap the planetary energies—whose origin was ultimately the blunt forces of gravity, mass and torque—all for the use of life.

  The potential-trees felt Lissa’s presence quickly enough. They had evolved defenses against poachers who would garner stray voltages and currents from the unwary.

  In concert—for the true living entity was the grove, comprising perhaps a million trees—they reacted.

  Staggering back to her lander, pursued by vagrant electrical surges through both ground and the thick air, she shouted into her suit mike her conclusions. These proved useful in later analysis.

  She survived, barely.

  3.

  When the sum of these incidents sank in, the full import become clear. The entire Shiva ecology was electrically driven. From the planet’s rotation and strong magnetosphere, from the tidal stretching of the Centauri system, from geological rumblings and compressions, came far more energy than mere sunlight could ever provide.

  Seen this way, all biology was an afterthought. The geologists, who had been feeling rather neglected lately, liked this turn of events quite a bit. They gave lectures on Shiva seismology which, for once, everybody attended.

  To be sure, vestigial chemical processes still ran alongside the vastly larger stores of charges and potentials; these were important for understanding the ancient biosphere that had once governed here.

  Much could be learned from classic, old-style biology: from samples of the bushes and wiry trees and leafy plants, from the small insect-like creatures of ten legs each, from the kite-birds, from the spiny, knife-like fish that prowled the lakes.

  All these forms were ancient, unchanging. Something had fixed them in evolutionary amber. Their forms had not changed for many hundreds of millions of years.

  There had once been higher forms, the fossil record showed. Something like mammals, even large tubular things that might have resembled reptiles.

  But millions of years ago they had abruptly ceased. Not due to some trauma, either—they all ended together, but without the slightest sign of a shift in the biosphere, of disease or accident.

  The suspicion arose that something had simply erased them, having no further need.

  The highest form of life—defined as that with the highest brain/body volume ratio—had vanished slightly later than the others. It had begun as a predator wider than it was tall, and shaped like a turtle, though without a shell.

  It had the leathery look of the tile-polygons, though. Apparently it had not followed the classic mode of pursuit, but rather had outwitted its prey, boxing it in by pack-animal tactics. Later, it had arranged deadfalls and traps. Or so the sociobiologists suspected, from narrow evidence.

  These later creatures had characteristic bony structures around the large, calculating brain. Subsequent forms were plainly intelligent, and had been engaged in a strange manipulation of their surroundings. Apparently without ever inventing cities or agriculture, they had domesticated many other species.

  Then, the other high life forms vanished from the fossil record. The scheme of the biosphere shifted. Electrical plant forms, like the spindly trees and those species that fed upon piezoelectric energy, came to the fore.

  Next, the dominant, turtle-like predators vanished as well. Had they been dispatched?

  On Shiva, all the forms humans thought of as life, plant and animal alike, were now in fact mere…well, maintenance workers. They served docilely in a far more complex ecology. They were as vital and as unnoticeable and as ignorable as the mitochondria in the stomach linings of Adventurer’s crew.

  Of the immensely more complex electrical ecology, they were only beginning to learn even the rudiments. If Shiva was in a sense a single interdependent, colonial organism, what were its deep rules?

  By focusing on the traditional elements of the organic biosphere they had quite missed the point.

  Then the Circular Ocean’s laser discharged again. The starship was nearer the lancing packet of emission, and picked up a side lobe. They learned more in a millisecond than they had in a month.

  A human brain has about ten billion neurons, each connected with about 100,000 of its neighbors. A firing neuron carries one bit of information. But the signal depends upon the path it follows, and in the labyrinth of the brain there are 1,015 pathways. This torrent of information flows through the brain in machine-gun packets of electrical impulses, coursing through myriad synapses. Since a single book has about a million bits in it, a single human carries the equivalent of a billion books of information—all riding around in a two-kilogram lump of electrically wired jelly.

  Only one to ten percent of a human brain’s connections are firing at any one time. A neuron can charge and discharge at best a hundred times in a second. Human brains, then, can carry roughly 1,010 bits of information in a second.

  Thus, to read out a brain containing 1,015 bits would take 100,000 seconds, or about a day.

  The turtle-predators had approximately the same capacity. Indeed, there were theoretical arguments that a mobile, intelligent species would carry roughly the same load of stored information as a human could. For all its limitations, the human brain has an impressive data-store capability, even if, in many, it frequently went unused.

  The Circular Ocean had sent discrete packets of information of about this size, 1015 bits compressed into its powerful millisecond pulse. The packets within it were distinct, well bordered by banks of marker code. The representation was digital, an outcome mandated by the fact that any number enjoys a unique representation only in base 2.

  Within the laser’s millisecond burst were fully a thousand brain equivalent transmissions. A trove. What the packets actually said was quite undecipherable.

  The target was equally clear: a star 347 light years away. Targeting was precise; there could be no mistake. Far cheaper if one knows the recipient, to send a focused message, rather than to broadcast wastefully in the low-grade, narrow bandwidth radio frequencies.

  Earth had never heard such powerful signals, of course, not because humans were not straining to hear, but because Shiva was ignoring them.

  After Badquor’s death and Lissa’s narrow escape, Adventurer studied the surface with elaborately planned robot expeditions. The machines skirted the edge of a vast tile-plain, observing the incessant jiggling, fed on the piezoelectric feast welling from the crusted rocks.

  After some days, they came upon a small tile lying still. The others had forced it out of the eternal jostling jam. It lay stiff and discolored, baking in the double suns’ glare. Scarcely a meter across and thin, it looked like construction material for a patio in Arizona.

  The robots carried it off. Nothing pursued them. The tile-thing was dead, apparently left for mere chemical processes to harvest its body.

  This bonanza kept the ship’s biologists sleepless for weeks as they dissected it. Gray-green, hard of carapace, and extraordinarily complex in its nervous system—these they had expected. But the dead alien devoted fully a quarter of its body volume to a brain that was broken into compact, separate segments.

&nbs
p; The tile-creatures were indeed part of an ecology driven by electrical harvesting of the planetary energies. The tiles alone used a far higher percentage of the total energetic wealth than did Earth’s entire sluggish, chemically driven biosphere.

  And deep within the tile-thing was the same bone structure as they had seen in the turtle-like predator. The dominant, apparently intelligent species had not gone to the stars. Instead, they had formed the basis of an intricate ecology of the mind.

  Then the engineers had a chance to study the tile-thing, and found even more.

  As a manifestation of their world, the tiles were impressive. Their neurological system fashioned a skein of interpretations, of lived scenarios, of expressive renderings—all apparently for communication outward in well-sculpted bunches of electrical information, intricately coded. They had large computing capacity and ceaselessly exchanged great gouts of information with each other. This explained their rough skins, which maximized piezo connections when they rubbed against each other. And they “spoke” to each other through the ground, as well, where their big, crabbed feet carried currents, too.

  Slowly it dawned that Shiva was an unimaginably huge computational complex, operating in a state of information flux many orders of magnitude greater than the entire sum of human culture. Shiva was to Earth as humans are to beetles.

  The first transmissions about Shiva’s biosphere reached Earth four years later. Already, in a culture more than a century into the dual evolution of society and computers, there were disturbing parallels.

  Some communities in the advanced regions of Earth felt that real-time itself was a pallid, ephemeral experience. After all, one could not archive it for replay, savor it, return until it became a true part of oneself. Real-time was for one time only, then lost.

  So increasingly, some people lived instead in worlds made totally volitional—truncated, chopped, governed by technologies they could barely sense as ghostlike constraints on an otherwise wide compass.