Center of Gravity

by Ian Douglas

  “Ship’s power on-line, at eighty percent,” the engineering AI reported.

  “Very well. Cast off umbilicals.”

  Connectors for power, water, and raw materials separated from America’s hull receptors, reeling back into the dock.

  “Dockyard umbilicals clear, Captain,” Carter reported.

  By this time, it was obvious that the H’rulka ship was intent on fleeing solar space, that America and the synchorbital naval base were not in immediate danger. Buchanan did not understand the alien’s tactical reasoning; the bastard could have approached the base closely enough to utterly destroy the base and perhaps a hundred warships docked there. That they had not done so suggested other mission imperatives—a strategic withdrawal, perhaps, to get reconnaissance data back home, but it ran counter to Buchanan’s own instincts.

  It suggested a certain conservative approach to their tactical thinking, which might be useful.

  “The ship is ready in all respects for space, Captain,” Commander Jones reported.

  “Very well. Cast off all mooring lines.”

  “Mooring lines retracting, Captain,” Carter reported.

  “Ship clear and free to maneuver,” the helm officer added.

  “Take us out, Helm. Best safe vector.”

  “Aye, aye, sir. Tugs engaged. Stand by for lateral acceleration.”

  “Attention, all hands,” the voice of the ship’s AI called over both link and audio comms. “Brace for real acceleration.”

  Buchanan felt a slight bump through the embrace of the doughnut as the tugs nudged America sideways and away from the dock. For several seconds, he felt weight, a distinct feeling of down in that direction, to his right. For the sake of clear communications, the navy took care to distinguish acceleration—meaning gravitational acceleration—from real acceleration, which was imposed by maneuvering thrusters or dockyard tugs. The former might involve accelerations of hundreds of gravities, but were free-fall and therefore unfelt. The tugs were shoving America’s ponderous mass clear of the docking facility with an acceleration of only a couple of meters per second per second, but that translated as two-tenths of a gravity, and a perceived weight, for Buchanan, of nearly eighteen kilograms—disorienting, and potentially dangerous for members of the ship’s crew who still weren’t strapped in. Out in the rotating hab modules, where spin gravity created the illusion of a constant half G, it was worse, as “down” began to shift unpleasantly back and forth with the hab modules’ rotation.

  He drummed his fingers restlessly on a contact plate. Best safe vector meant slow, and without benefit of gravitics. A mistake here could wreck a substantial portion of Fleet Base. By the time the carrier warped clear of the dock, the enemy ship—no, ships, he corrected himself—would be long gone.

  He’d half expected Koenig to reverse the orders to take America out of dock. If the enemy left the solar system, there was no need to continue. On the other hand, Koenig might be preparing for a further enemy incursion . . . or for a sudden change in course by the fleeing H’rulka vessels. The safe bet was to get all warships clear and maneuvering freely and to keep them there until it was certain the enemy threat had passed.

  There’d been no additional orders from the Admiral in CIC, and so Buchanan had continued to follow the last set of orders he’d received. Take her out.

  On the tactical display, some of the missiles fired by the Symmons an instant before her immolation were slowly closing on one of the H’rulka ship sections. . . .

  H’rulka Warship 434

  Sol System

  1544 hours, TFT

  With divergence, the situation had become considerably more desperate.

  Ordered Ascent drifted in the center of a claustrophobically enclosed space less than three times the diameter of its own gas bag, with scarcely enough room for its own manipulators and feeder nets to drift without scraping the compartment’s interior walls. Images projected by the ship across the ship-pod’s interior surfaces created the comforting illusion of vast, panoramic vistas of cloud canyons, vertical cloudwalls, and atmospheric abysses, but the touch of a tentacle against the invisible solid wall shattered the comforting sense of openness, and could bring on the sharp madness of claustrophobia.

  Each of the other vessels—434 had retained its number, but the others, upon divergence, had received new identifiers—was accelerating now on a slightly different heading, somewhat more vulnerable now to enemy weapons, and certainly more dangerous for the crew emotionally.

  The tactic essentially reproduced a natural response among H’rulka colonies that had evolved half a million gnyii among the cloudscapes of the homeworld. Certain pack hunters that had shared those skies with the All of Us preyed on adult colonies by attaching themselves to underbodies and slicing at them with razor-edged whip-tentacle limbs evolved to surgically sharp efficiency for the task. H’rulka survived by jettisoning their immense gas bags as the predators approached, allowing themselves to plummet into the Abyss; each colony-group separated naturally into twelve sub-colonies—divergence.

  Each sub-colony unfolded a new, much smaller gas bag, heating hydrogen through furiously pumping metabolic bellows to arrest the fall before the group dropped into the lethal temperatures and pressures of the Abyssal Deep, a descent of only a couple of thousand kilometers, and often less. In essence, the adult colony had reverted to a juvenile form, and much of the original colony’s intelligence and memory were lost. H’rulka civilization, in fact, had begun perhaps 125 gnyii ago with the collection of communal records maintained as a kind of living, constantly recited encyclopedia broadcast endlessly over certain radio frequencies. Those records were a direct response to the effects of the predators on the cloud communities at large, and had led, ultimately, to the discoveries of science, of polylogue mathematics, and, eventually, technology.

  But divergence was still exceptionally traumatic for All of Us colonies, and some of the terror associated with the breakup and the precipitous fall continued to haunt them even when the divergence was strictly technological, a means of ensuring that one, at least, of the H’rulka colonies would make it back to base.

  Enemy weapons were pursuing several of the retreating pods. None were in close proximity to Warship 434, but Rapid Cloud in 440 and Swift Pouncer in 442 both were being closely pursued by what appeared to be intelligent, self-steering missiles. The devices were primitive technologically, compared with All of Us singularity projectors, but would possess nuclear warheads that might seriously damage even an intact H’rulka warship.

  Only a few vu more, and they would be able to slip into the safety of bent space.

  A trio of dazzlingly white flashes ignited close alongside Swift Pouncer, and another just behind Rapid Cloud. Ordered Ascent felt the electromagnetic pulse, felt the telemetry warning of systems failure . . .

  But then critical velocity was reached, and the retreating colony-pods began dropping into bent space.

  Chapter Six

  21 December 2404

  CIC, TC/USNA CVS America

  Earth Synchorbit, Sol System

  1532 hours, TFT

  Admiral Koenig sat in his workstation in America’s Combat Information Center, the large, circular compartment that served as the command nerve center for the entire carrier battlegroup. The surrounding bulkheads were currently set to show the view from the carrier’s external optical sensors, the input from dozens of cameras merged by computer into a seamless whole that edited out the sheer cliff of the shield cap forward, and the kilometer-long length of the spine aft. At the moment, they showed the docking facility receding slowly to port, and the much vaster sweep of the entire SupraQuito base beyond, partially blocking the slender, brilliant crescent forward that was Earth.

  Dozens of other ships filled the sky. Half of CBG–18 had been docked at the base, the other half on patrol as far out as the orbit of Luna. Koenig had given orde
rs for all of the battlegroup’s ships to get clear of the port as quickly as possible, and to deploy in the general direction of the intruder.

  The precaution, it seemed, had been needless. The intruder was now accelerating rapidly out-system, pursued by a number of Confederation vessels. Moments before, it had lashed out at seven of the closest vessels and destroyed them, including the destroyers Kaufman and Symmons, and the frigate Milton, all members of CBG–18. Symmons had gotten off a spread of Mambas, however, and those were slowly closing on the enemy, which had just, unaccountably, divided into twelve smaller vessels.

  The enemy was now about one light minute distant, and moving so quickly—close to sixty thousand kilometers per second—that it was likely that, by now, those ships had already either gone into metaspace or been struck by Symmons’ salvo.

  The intruder’s behavior was puzzling, to say the least. H’rulka military technology was, at a guess, a century or two ahead of Earth-human mil-tech. At the Battle of 9 Ceti twelve years ago, a single H’rulka warship had wiped out a small battlefleet of fourteen Confederation vessels, including the light Star Carrier Illustrious. Their primary ship weapon appeared to be a means of creating small gravitational singularities, artificial black holes launched at high velocity and with unerring precision, something that was completely beyond current human technology. Their drive systems were better, too; their huge ships could accelerate faster than any human warship, as fast or faster than many human missiles, and their equivalent of Alcubierre Drive allowed them to drop out of metaspace much deeper within a target star system than could human vessels.

  With those advantages, why had the intruder gotten as close to Earth as Earth’s moon, less than two light seconds away . . . and then turned tail and run? The obvious answer—that they’d decided to return valuable data to their home base or fleet rather than risk a general engagement—was only a small part of the story. They could have wiped the Confederation fleet out of the sky, wrecked Earth’s space elevators, and left the planet almost completely helpless.

  And that was just one ship.

  Or, arguably, twelve. Koenig wasn’t yet sure what to make of that twelve-in-one surprise trick.

  The tugs were drawing back from America’s flank. In another minute, the ship scene outside began to swing counterclockwise as the carrier pivoted . . . and then the dockyard slid past and fell away astern. America was under way at last.

  “Admiral?” Captain Wizewski called over the CIC net. “Permission to begin launching fighters.”

  Koenig checked the readout on squadron flight status. The last of VQ–7’s Shadowstars had dropped from their hab module launch bay moments before America had been nudged clear of the dock. And VFA–49 was on Ready Five, ready for launch in five minutes.

  “Let’s hold that, CAG,” Koenig decided. “Give the Peaks some space to run their metrics. I want to know if that intruder is alone, or if there are lurkers.”

  “Aye, aye, sir.”

  Starships, even monsters like the fleeing H’rulka craft, were insignificantly tiny against the backdrop of an entire star system. Even in the Sol System, heavily traveled and scattered with bases, outposts, and comm relays, at ranges of more than a few kilometers the largest ships were essentially invisible if they weren’t powered up and under way. Those H’rulka vessels were sharply visible at a range of one light minute, now, because their drive singularities were creating the three-dimensional equivalents of wakes as they plowed through empty space.

  If they weren’t moving, if their power plants were off and their life support was drawing battery power only, if their IR emissions were damped, if they weren’t being directly painted by radar or lidar, no one would know they were there. Koenig was concerned that the chase now being played out between the orbits of Earth and Mars was a diversion, a show arranged to convince the Confederation fleet that the threat was gone, perhaps even to draw defending ships away from Earth herself.

  America’s reconnaissance squadron had especially sensitive instrumentation that would detect all but the most stealthy of stay-behind lurkers.

  And the squadron now ready for launch off America’s forward rails was VF–41, the Star Tigers, a squadron still flying the older SG–55 War Eagles. They didn’t have anything close to the acceleration necessary to catch the receding H’rulka ships, and their drive singularities would screw the local metric of space, making it impossible for the Sneaky Peaks to pick up powered-down lurkers.

  If there wasn’t an immediate need to get America’s complement of fighters off her decks, it would be better to let the recon squadron do what they did best . . . scouting ahead, looking, listening, sensing with every electronic trick at their disposal for the presence of hidden enemy craft.

  “Captain Buchanan?” Koenig said.

  “Yes, Admiral?”

  “I want—”

  A close-spaced trio of nuclear fireballs pulsed against the darkness ahead.

  “Direct hit on one of the enemy ships!” Commander Sinclair called. In the next instant, a fourth fireball appeared, expanding, slowly fading from its initial glare of incandescence.

  “Ten of the H’rulka craft have just gone FTL,” Commander Katryn Craig, the CIC’s operations officer, reported. “Two appear to have lost their drives.”

  Several people in the CIC cheered.

  “Belay that,” Koenig snapped. “We don’t have them yet! CAG, put the Star Tigers over there. I want a closer look at those ships.”

  “Aye, aye, sir.”

  Both H’rulka vessels were continuing to travel out-system on divergent paths with the same velocity they’d had when their drives were cut—about sixty thousand kilometers per second.

  “Commander Craig?”

  “Sir.”

  “We need a VBSS team over there. What assets do we have in the area?”

  “SBS–21 is at SupraQuito, Admiral. And the Tarawa is there too.”

  “Let’s give this one to the SEALS. Patch a call through.”

  “Aye, sir.”

  “Captain Buchanan.”

  “Sir.”

  “Take us closer to those disabled ships. We’re going to put some fighters in that area.”

  “Yes, Admiral.”

  America swung slowly to one side, accelerating. The cluster of habs and facilities at Synchorbit fell rapidly astern, followed a moment later by Earth’s moon.

  Ahead, the four nuclear fireballs from Symmons’ barrage continued to expand and fade.

  ONI Special Research Division

  Crisium, Luna

  1612 hours, TFT

  “We are trying,” Dr. Wilkerson said slowly, “to understand you.”

  He heard the rasping buzz of the Turusch language as the AI translated his words and put them out through the NTE robot.

  From his point of view, he was hovering above the deck in one of the rooms off to the side of the main Turusch colony cavern, occupying a white sphere hanging from the ceiling. In front of him was the pair of alien Turusch brought back from Eta Boötis two months before—the two known jointly as Deepest Delver of the Fourth Hierarchy. Each looked like an immense terrestrial slug, more or less, but with the forward quarter of the body covered by a jointed carapace, and the belly covered by leaf-shaped, overlapping scales. Slender tentacles, always in whiplash motion, sprouted from seemingly random parts of the unarmored bodies.

  The two, Wilkerson knew, in some way not yet fully understood by human xenosophontologists, were in fact one. They seemed to think of themselves as a single individual—as Deepest Delver. Two separate brains—and yet neuropattern scans had shown that their brains appeared to fall into synch with each other when they spoke, using a buzzing sound generated by four tympani located in recessions on either side of their armored heads.

  He heard the Turusch reply in a humming buzz. On the translation window open inside Wilkerson’s
mind, he read three lines of dialogue.

  Deepest Delver 1: “I occupy my world.”

  Deepest Delver 2: “You occupy your world.”

  Joint: “There is no understanding.”

  A dead end. Again. Wilkerson sighed with pent-up frustration, and not a little exhaustion. He’d been at this questioning for over three hours now.

  This three-part trilogue was a defining characteristic of the Turusch. When they spoke, the speech of one overlapped the speech of its twin. The two sets of sound together generated resonating, harmonic frequencies that produced the third line, carrying a third, higher-level meaning.

  Wilkerson stared through his robotic avatar for several moments. What kind of brain could think on multiple levels at once like that? It was possible, probable, even, that the Turusch in absolute terms were far more intelligent than humans; certainly they were far quicker in their thought. But they were so completely alien that humans might never be able to understand them well.

  There is no understanding. . . .

  “Dr. Wilkerson? Dr. Wilkerson!”

  He blinked. A communications request light had been blinking at the periphery of his awareness for some minutes now. The voice was that of Caryl Daystrom, one of the other ONI researchers at the facility.

  “Yes, Caryl,” he said.

  “I’m sorry to interrupt, Doctor, but there’s an important message for you. Priority Alpha.”

  He sighed. “I’m coming out,” he told her. Opening the channel to the Turusch pair, he said, “We will continue this later. There must be a way for us to truly understand one another.”

  Deepest Delver 1: “We will share speech again.”

  Deepest Delver 2: “I, too, desire understanding.”

  Joint: “Your thought is shallow.”

  He made a mental note to check in with the R & D lab. “Your thought is shallow” was a frequent complaint made by the Turusch to human interrogators. Used to thinking and speaking with one another on three levels simultaneously, they appeared to be frustrated in conversations with humans, who could carry on only one line of dialogue at a time. So far as they were concerned, that was the greatest impediment to full and intelligible communications.