Star Strike. Ian Douglas

Earth orbit, on Luna and Mars, in the Asteroid Belt, and farther out, among the satellites of Jupiter. Billions died on the Motherworld, first in the holocaust of falling debris, then of starvation and exposure as the snows deepened and the oceans began icing over. But technological help had begun pouring in from the space-based colonies, especially from the orbital nanufactories, untouched by the devastation wrought on Earth. Nanufactured food, power plants, and constructors had been loaded into immense one-trip gliders by the megaton and deorbited for recovery in the ice-free equatorial zones of Earth’s oceans. Within another century, one, then dozens of space elevators had been lowered into place, connecting points along the equator with matching points in geostationary orbit, after which the supplies had really begun flowing down the pipelines from space. Ground-based agricultural nanufactories had begun producing food locally, then, along with nano designed to break down ice, lower the skyrocketing planetary albedo, and clean up the detritus of a wrecked technic civilization.

      Slowly, then, the recovery had begun.

      And five centuries later, that recovery was continuing. New cities were growing now along the shockingly altered Atlantic coastlines. Most of the gangs and local warlords had long since been suppressed, or incorporated into the new government. North America and most of Europe were no longer dependent on supplies from space.

      Of course, the former United States was now a special protectorate of the Commonwealth, a necessary adjustment in the face of the aggressive expansion of the Chinese Hegemony. And the Islamic Theocracy continued to be a perennial problem, ruled from the Principiate of Allah, at Mecca. Sharp wars had been fought with both states to protect both the Americas and Europe.

      Alexander allowed himself an inner, unvocalized sigh. The real enemy, as always, remained the Xul, and for half a millennium Humankind had continued its divided, petty squabblings among its various fragmented religious, political and economic factions. This current unpleasantness with the Theocracy was only the latest in eight hundred years of bloodshed that stretched all the way back to WWIII, and which some historians insisted went back even further, to the Crusades of the Middle Ages.

      Still adrift just above the galactic plane, Alexander gave a mental command and allowed his mind’s eye to descend into the sea of stars, moving out toward the spiral arms, toward one spur of a spiral arm in particular, about 23,000 light-years from the center. The vast majority of the stars in this simulation were approximations only, with no hard information about the stars or the worlds that might be circling them. Some day, perhaps … but for now Humankind’s knowledge of its celestial neighborhood was sharply restricted to an unevenly shaped blot perhaps 800 light-years across in its longest dimension, less than one percent of the vast and pinwheeling whole.

      Ahead, the stars embraced by the Commonwealth and the other governments of Humankind glowed within a soft, green haze of light. Individual star systems were labeled with alphanumerics giving names and provenance—with Sol imbedded roughly at the center. Another mental click, and the green light fragmented into various shades of yellow, blue, and green, identifying the Islamic Arm, the Chinese Arm, the Pan-European Arm, the Latino Arm, the Commonwealth, and the rest.

      He brought up a red icon marking the position of the lost Argo … 500 light-years from Sol, and on a direct line with the Andromedan Galaxy. She’d been well outside of human space when the Xul had discovered her; the outer fringes of Islamic space lay a light-century or so in her wake.

      Orange pinpoints marked those outposts and garrisons of the Xul that had been identified over the past few hundred years, a fuzzy and diffuse cloud outside of human space; none lay close to Argo’s outbound route, but that was scarcely surprising. The Xul empire spanned the Galaxy and stretched well beyond it; Humankind thus far had identified only a few hundred Xul outposts and bases, and the best guess suggested that the Xul held a million star systems, or more.

      “We now have a candidate star for another Xul base,” Herschel whispered in Alexander’s ear. “Here …”

      A star was highlighted in blue, and Alexander zoomed in on it. Nu Andromedae, a type B5 V blue-white sun some 440 light-years from Earth. From Earth’s perspective, the star by chance appeared just to the east of M-31.

      “The Argo must have passed quite close to Nu Andromedae,” Herschel added. The AI painted a red contrail streaming from the Argo, like a thin, taut thread stretching all the way back to Sol, and the line skimmed past Nu Andromedae, almost touching it. “Less than three light-years, in fact.”

      “Maybe. But that was still over a hundred years ago. Why should the Xul wait that long before pouncing?”

      “For the same reason the Xul have not found Earth, General. The term once in use was ‘a needle in a haystack.’”

      Alexander had never seen either a sewing needle or a haystack, but the phrase was descriptive enough in its own right. Even the Xul, powerful and technologically advanced as they were, couldn’t be everywhere, couldn’t watch every star system or world where life might have evolved. The Galaxy was far too large for that level of omnipotence, even for beings with powers indistinguishable from those of gods.

      “Herschel’s right, General,” his aide pointed out. “The Argo was a hollowed-out asteroid. Its passengers were in deep cybe-hibe. Even at close to the speed of light, it wouldn’t have been giving off much in the way of anomalous radiation.”

      “I don’t buy it, Cara. We know now it would have been giving off a kind of wake as it plowed through the dust and hydrogen atoms floating around in its path—the interstellar medium. We can detect that sort of thing ourselves. If we can do it, the Xul can as well.” He studied the display a moment longer, rotating the display and studying the contrail. “Herschel … check distances from the contrail to nearby stars, and correlate with the one-way time lags. Assume radio noise expands from the Argo at the speed of light, and a more or less immediate response from the target star once the RF wave front reaches it.”

      “Yes, General.” Angles and geometric designs flickered from star to star, touching the contrail at various points as the artificial intelligence searched for a better fit.

      “Actually … that star is a better candidate,” Alexander said after a moment, indicating a particular geometry.

      “Epsilon Trianguli,” Cara said, calling up the data window on the indicated star. “Type A2 V. Four hundred fifty light-years from Earth—”

      “And 110 lights from the contrail at its closest passage,” Alexander said. “The Argo streaks by, disturbing the interstellar medium. The radio noise spreads out, like the wake of a boat on a calm lake, and reaches Epsilon Trianguli 110 years later. A Xul ship or base takes note and dispatches a force to investigate.”

      “There are twenty-five other stars with corresponding distances, angles, and lag times,” Herschel told them, “albeit with lesser probabilities.”

      “Store the data, Hersch,” Alexander said. “We may want to do a careful analysis, maybe even send a sneak-and-peek team out there for a look around.”

      “Aye, aye, sir.”

      For centuries, the Marines and Navy had dispatched scouting forces out from human space—sneak-and-peek teams, as they were popularly known—in order to try to identify specific stars where the Xul maintained a presence. The idea was that if Xul bases or colonies could be found, they could be watched, with an eye to noting any sudden activity that might presage a new assault against human space.

      The sheer vastness of space, the grains-of-sand numbers of stars, worked both ways, however. For centuries, they’d hidden Sol from the Xul, protecting the existence of Humankind, but those same numbers allowed the vast majority of the Xul outposts to remain hidden as well.

      But the further into interstellar space Humankind probed, the greater the chance, the more certain the inevitability, that it would once again trip the Xul sentries, as it had on several occasions already. And it seemed all but certain that, when the Xul returned to the Motherworld of Humankind, they would come with sufficient force to finish the job