Dark Mind

by Ian Douglas

  The sky around Gregory now looked like the fictional ones, however, packed with boulders of all sizes, ranging from bits of rubble to drifting mountains. The belt’s density was not uniform. Mutual gravitational attraction had pulled the debris together until the stuff was orbiting in tight formation. Elsewhere, there were vast gaps.

  Caswell and Ruxton had already checked the composition of a couple of the fragments, firing lasers at them and spectroscopically analyzing the gas given off. One piece had been mostly nickel iron; the other had been an amalgam of steel and plastics, probably derived from a carbonaceous chondrite—a type of asteroid rich in hydrocarbons.

  That supported the classic theory of a Dyson sphere’s construction. You needed to disassemble all of the planetary and asteroidal bodies in the system to get enough material to build a structure that big.

  The idea seemed a bit harebrained to Gregory. What kind of idiot wiped out his entire solar system in order to get the raw materials to build an artificial habitat? It seemed . . . short-sighted, somehow. You might need that stuff some day.

  A signal flashed in Gregory’s in-head. That was odd. . . .

  “Hey, Skipper?” he called. “This is Demon Four. I’ve got an IR point source dead ahead. Range . . . I make it about two thousand kilometers.”

  “Copy that, Four,” Mackey’s voice replied. “Check it out . . . but watch yourself.”

  He accelerated his Starblade, homing on the infrared signal.

  So far, the endless debris fields had been lifeless. But it was easy to envision that there must have been life here at some point, beyond the presence of the artificial object itself. Some of the fragments he was passing, the larger ones, especially, showed hints of mountains, river beds, even occasional structures of some sort. The terrain forms looked molded, as if the shell had originally been grown to include preformed shapes for mountains, hills, valleys, and other terrain features. Presumably, the entire surface had then been covered with dirt, water, and growing things to artificially replicate the surface of a planet.

  A very, very, very large planet . . .

  And a few of those fragments showed infrastructure . . . tunnels or roads or underground blocks of buildings, perhaps, laid out in geometric precision within the Dyson floor substrate.

  These guys had thought big.

  There wasn’t nearly enough wreckage to suggest a true Dyson sphere, though, and that was a bit of a puzzle.

  Yes, the debris field was massive and extensive, but it still didn’t look like it held that much material. It might well have been a ringworld, however, an enormous flattened hoop spinning to create artificial gravity on the inner surface, and with titanic walls along the edges to hold in the atmosphere and keep it from spilling off into space.

  Or . . . perhaps it had been a sphere once, but most of the pieces had fallen into the star. But there also was the mystery of the statites.

  Out beyond the belt of wreckage, asteroid-sized constructs hung suspended from gossamer sails, each a few molecules thick, but stretching across an area equivalent to half of North America. The Black Demons had passed a few of them an hour ago on their way in to the debris belt. Balanced between the star’s gravity and its radiation pressure, these stationary satellites did not appear to be habitats. Clearly they were arranged to take advantage of the star’s abundance of light. They might be the classic alternative to a Dyson sphere, a mega-engineering concept called a Dyson swarm, which had many fewer problems than the sphere version. So the consuming question here at Tabby’s Star was . . . why had the builders of this place used both? If the belt debris had been a Dyson sphere, the statite spheres farther out would not have been able to harvest sunlight. Possibly, if the inner structure had been a band around the sun’s equator and not a complete shell, the statites could have hovered above just the exposed portions of the star . . . an elegant design combining both megastructural elements. But, again—why?

  Gregory knew that they didn’t have the full picture yet. He wondered if the belt debris had been an earlier attempt at either a ringworld or a solid sphere that had failed, and the statite swarm had been put in place later. Maybe. That made a certain amount of sense, he thought, though he admitted to himself that that might be the depression talking. He had a tendency to get cynical when he got depressed.

  Or . . . maybe the two different designs represented two different civilizations, perhaps separated by millions of years in time. The ringworld civilization might have given rise to the statite cloud, or the statite builders might have been invaders coming in from elsewhere. Gregory could imagine the statite civilization scavenging the belt debris for raw materials.

  Had there been a war between the two? Had an invading intelligence destroyed the ringworld, then feasted on its remains?

  At any rate, the Ghost Riders were checking out the statites now; the Black Demons had been deployed inward to examine the debris belt farther in. The only way they were going to solve this mystery was if they could find someone, something living here they could question. The belt debris was lifeless . . . but there might be AIs existing among the statites. Or digitally uploaded intelligences. If they could just make contact and learn how to communicate with whatever was left.

  His Starblade was decelerating now within a few hundred kilometers of the IR source, but he couldn’t see anything up ahead like an intact structure or ship. What he did see was a filmy, gauzy something that appeared to be growing out of a piece of floating rubble. At first he thought there was a fault with his ship’s optics, but the fighter’s AI assured him that everything was functioning optimally.

  And then the gauzy something moved.

  The diaphanous shape flowed and rippled, parts of it moving like water, parts shifting like aurorae. The IR signal, he saw, was coming from the chunk of debris, a house-sized hunk of metal floating at the edge of the far vaster translucence beyond it. Whatever that cloud or shape was, it was enormous. He couldn’t get a radar return off of it, but he was able to compare it visually to a nearby drifting fragment that he could measure.

  The shape—what he could see of it, at any rate—was 120,000 kilometers across, very nearly the diameter of the planet Jupiter.

  He was picking up a magnetic field from the thing too, a strong one.

  The scary part was that Gregory could not escape the feeling that whatever that thing was, it was alive. It appeared to be grazing along the fringes of the debris belt.

  “Hey, Skipper!” he called. “Are you getting this?”

  “We see it,” Mackey replied. “Is that thing alive?”

  “Sure looks like it. I’m going to try to get in closer.”

  “Not too close! And kill your speed a bit! Whatever that thing is, you do not want to get it mad!”

  “Copy that.”

  Gregory shifted his Starblade’s outer hull to complete stealth mode, an utterly black, light-drinking modality designed not to be noticed. He engaged his AI’s analytical routines, probing and measuring . . . but gently.

  He was thinking about his wild-ass idea about interstellar invaders. The diaphanous, magnetic thing out there was as insubstantially thin as the solar sails supporting the statites. Could it be associated with them? Could a civilization of those beings have made the statite cloud?

  Somehow, that didn’t seem right . . . a being as insubstantial as a smoke cloud the size of Jupiter building billions of statites each forty kilometers across. No, that didn’t make sense on any level.

  His Starblade’s AI warned him, in feelings rather than words, that his fighter was moving through a volume of space of slightly higher density than before.

  So-called empty space was not entirely empty, it turned out. In interstellar space, out among the spiral arms of the galaxy, a traveler would encounter roughly one atom per ten cubic centimeters of space. Inside a solar system, that went up to perhaps five particles per cubic centimeter—mostly stray hydrogen atoms, or the stray protons that made up much of the solar wind.

 
Here, in the vicinity of the debris belt, the local density was more like a hundred particles per cubic centimeter, mostly stellar-wind protons, but also a lot of dust—the result of the steady erosion of the Dyson fragments. But his fighter’s sensors had just recorded a jump in the density of the interplanetary medium up to nearly a million ppcm3.

  That still qualified as hard vacuum, of course. At sea level on Earth, the density of the atmosphere averaged 1019 molecules per cm3, some 10 trillion times thicker than this.

  But this stuff was thick enough for friction to heat the outer hull of his Starblade, and he felt a shudder as he moved through it.

  The cloud or mass, or whatever the hell it was, was still visible ahead. Evidently, it had no well-defined edges, but existed within an amorphous and invisible envelope that grew gradually denser—and more visible—the deeper you traveled into the thing. The main body of the thing could feel him, though. He could see ripples moving back through the filmy shape ahead, ripples originating with him as his Starblade penetrated the shifting, transparent mass.

  “Don, is that thing alive?” DeHaviland asked. Her Starblade was a thousand kilometers behind his, and coming up fast.

  “I’m not sure. I think so, yeah.”

  “We’re reading a hell of a high magnetic flux in there,” Mackey said. “I don’t know what’s powering it, but it’s putting out a field of between two thousand and five thousand gauss.”

  It threw a rock at him.

  An alarm sounded in Gregory’s head. The boulder the cloud had been attached to had suddenly been propelled directly toward his spacecraft, moving at well over 100 kilometers per second, fast enough that even the tenuous cloud of near-vacuum heated it white-hot. He wrenched the Starblade hard to port, rolling sharply, and accelerated. The oncoming rock swerved, manipulated by the magnetic field within the creature, and he twisted to port again.

  The rock, longer than his Starblade, tumbled past, bits of white-hot debris dropping off in its train. As Gregory boosted harder, his fighter emerged from the invisible envelope, his velocity increasing as he hit open space.

  “Damn it to hell!” he shouted. “That thing just took a shot at me!”

  “Watch out, Don!” DeHaviland warned. “It’s closing on you!”

  The transparent mass was accelerating, moving directly toward him. Gregory adjusted his course to take him back toward the main body of fighters. He found he could outpace the cloud, but it was damned unnerving, having a transparent haze on his tail, deliberately trying to run him down.

  “Demon One, Demon Four!” he called. “Request permission to fire!”

  “Negative, Four! RTB, repeat, RTB!”

  RTB—Return to base. “Copy that, One. On my way.”

  “Don! Watch to your six!”

  Another white-glowing missile was hurtling out of the cloud behind him, moving much faster this time. “I see it!”

  He rolled right . . . but slow, too slow. . . .

  The missile shattered in a bright flash of light. Cyndi DeHaviland had speared it with a particle beam. Gravel clattered along the length of his Starblade, the impacts causing no damage.

  “Thanks, Cyn.”

  “Don’t mention it. Let’s get back to the barn.”

  “Negative! We’ve got to stop that thing!” He hauled his Starblade into a broad, sweeping turn, chasing his own fast-flickering gravitational singularity. The creature, or whatever it was, had expanded, was looming across all of space dead ahead, as though reaching out to embrace him.

  “Demon Four!” Mackey called. “What the fuck do you think you’re doing?”

  “We need to know what that thing is, Skipper!” he called back. “And it would be nice to know how to kill it!”

  “ROE One, Gregory! ROE One!”

  “ROE your fucking boat!” he snapped back . . . and his Starblade plunged into the faintly translucent haze. He thoughtclicked a pair of icons, arming two Krait missiles.

  Gregory realized that he wasn’t thinking clearly, that anger was taking over. He told himself that they couldn’t lead that alien life form back to the carrier, but that thought was more justifying smokescreen than rational thought.

  His fighter shuddered and bucked. What the hell?

  “Don did something to it!” DeHaviland said. “I think he just gave it a kick in the ass!”

  “What’s it doing?” That was Bruce Caswell.

  “It’s shrinking!” Gerald Ruxton replied.

  The diaphanous mass had been stretched out across an enormous volume of space, but now it seemed to be collapsing on itself. And as it did so, it began falling into the debris belt.

  “Gregory!” Mackey snapped. “Break off and get the hell back here!”

  Gregory hesitated, poised for an eternally long second at the thin, ragged edge of a precipice. Two kraits were armed and ready to boost.

  “Don!” DeHaviland called. “Meg wouldn’t want you to do it!”

  The words blasted in out of nowhere, confusing, hurting, stirring memories that had no business in a fighter-pilot link. “What?”

  “Break off, Don!”

  “Break off, Demon Four! That’s an order!”

  “C-copy.” Damn it all to a flaming red hell!

  The alien, drifting in the general direction of Tabby’s Star, vanished behind a tumbling chunk of debris. It had collapsed down to a grayish, smooth ovoid less than a kilometer across, so dense that it now was completely opaque.

  Was that behavior evidence of high intelligence, of military tactics? Or simple animal cunning?

  Either way, he’d had his fill. Gregory pivoted his Starblade about his drive singularity, killed his forward velocity, and began boosting back toward America. The anger receded . . . still there, but tempered now by reason. Damn, he’d never lost it like that before. . . .

  ROE One was a set of standing orders encompassing all first contact scenarios. “ROE” stood for Rules Of Engagement, and they were designed to avoid unfortunate misunderstandings with sapient life forms, both those poorly understood and those never before encountered. Centuries ago, the term had evolved in military circles to impose diplomatic or political rules on soldiers . . . preventing them from firing first, and even in extreme and particularly stupid cases preventing them from carrying loaded weapons inside combat zones. Though warfare had been famously referred to by von Clausewitz as politics continued by other means, the two—politics and warfare—did not mix well at all.

  ROE One, though, had a certain amount of sense to it. When human military or exploration vessels encountered a new species, they went into the contact situation with no idea of the motivation or psychology or even type of intelligence they were facing. Given that most star-faring species encountered by Humankind so far had been more technologically advanced, it was in the best interests of humans not to get into an accidental shooting exchange with aliens of unknown potential, origin, or capability.

  And he had almost screwed that up.

  Gregory took a long, shaky breath. “Okay. I’m coming in.” Again, he arced his fighter around in a smooth one-eighty, picked out America’s nav beacon, and boosted for home.

  He had the distinct and uncomfortable feeling that somewhere astern, that alien whatsis was watching him go.

  VFA-190, Ghost Riders

  Tabby’s Star

  1302 hours, TFT

  Lieutenant Commander Caryl Zhang guided her Starblade across a seemingly infinite vista, a flat geometry that appeared to stretch away in every direction. She could not avoid the somewhat creepy feeling that she was being watched intently.

  “Keep alert, Riders,” she called. “This thing is spooking me.”

  “Copy that, Rider One,” Lieutenant Brodowsky replied. “You think this is another Rosetter artifact?”

  “I doubt it, Eight. Completely different technology. But that doesn’t mean it’s friendly, right?”

  The Ghost Riders had been deployed starward to investigate the outer shell of objects suspended above Tabby’
s Star, beginning just outside the debris ring. From what they’d been able to see so far, after half an hour of flying over a black and endless panorama, the shell was big and it was silent. Repeated attempts to communicate with the thing had come up empty.

  Maybe the Demons are having better luck, she thought. She hoped that was the case.

  In fact, the Ghost Riders had detected five complete shells of statites surrounding Tabby’s Star, with the inner one at about two AUs’ distance from the star, just outside the debris ring, and the outer one at five and a half AUs, here. As America’s long-range scans had revealed, each shell was made up of some hundreds of millions of stationary satellites—forty- to fifty-kilometer teardrops suspended several thousand kilometers beneath enormous, circular light sails.

  Those light sails were incredible—each three thousand kilometers across, the distance, near enough, between her birthplace in the State of South California and her current residence in New Chicago. What made them more incredible was how gossamer thin they were . . . no more than a few molecules thick. Those sails had some complex chemistry going on, though. They seemed to vary, depending on the angle from which you looked at them, from completely transparent to ebon-black. Clearly, they were absorbing a lot of starlight and converting it to energy; clearly, too, they were capturing the momentum of outbound photons and using the radiation pressure to keep the entire structure hovering in place above the star.