Redwing pondered. Empty? Conventional astronomy held that a cloud of interstellar shrapnel and bric-a-brac orbited stars, the mass that did not collapse to make the star or its planets. In his early career, he had piloted a ramscoop on one of the first runs into the solar Oort cloud, and done well in that vast volume. They had ridden SunSeeker out into the Oort then; tried the flaring, rumbling engines; found flaws that the previous fourteen ships had missed. Redwing had overseen running the Artilect AI systems then, found the errors in rivets and reason, made better. In the first few generations of interstellar craft, every new ship was an experiment. Each learned from the last, the engineers and scientists did their burrowing best, and a better ship emerged from the slow, grinding, liberating work. Directed evolution on the fast track.
Redwing had emerged from that. Now he was among the first generation of starship commanders. They had had to make a huge leap, from the fringes of the solar Oort cloud into interstellar distances. They were all scattered light-years apart, separated by centuries of cold sleep. Their laser tightbeam signals from Earth peppered the lunar center in what now seemed to be called the Home System. He had reviewed tales of expeditions to Tau Ceti and other famous stars, those much closer to Sol than Glory. Matters were a building around the Alpha Centauri system, still the richest lode of useful planets, with colonies now, no less.
This expedition to find the grav wave emitter was a giant jump, a factor of 100,000 beyond the mere Oort cloud expedition he had started with—like sailing around the world after a trial jaunt around a sandbar three football fields wide.
This star had a spherical outer Oort cloud of suspiciously low density— an iceteroid every astronomical unit or so—but now the inner Oort disk was ... gone. Redwing dimly recalled that the astro people believed that Oort clouds held several planetary masses usually, dispersed into tiny iceteroids. Into whatever was emitting grav waves, maybe? But invisible?
"So what's this empty field telling me?" Redwing gestured to Cliff Kammash to expand the view near them. SunSeeker was about a thousand AU out from the target star, Excelsius, and there was nothing luminous in the vast volume.
Cliff's brow furrowed. "Not much. Running the range now."
Redwing watched the ship's Artilects offer up views across the entire electromagnetic spectrum. Pixels jittered, shuffled, merged. Visible light was a mere one octave on a keyboard fifteen meters wide—humanity's slice of reality. "Except—here's the plasma wave view, and—bingo!"
A long ellipsoidal cloud bristled in shades of rude orange. "Color coded for plasma wave density," Cliff said. "Blotchy."
"This odd little zone is the only mass of any consequence in the entire outer system?" Beth said skeptically, mouth skewed. "And it's not self-luminous at all in anything but plasma emissions?"
Redwing said to the Artilect system in his spaced, patient voice, "Display all detected plasma emissions—all-frequency spectrum."
SunSeeker's system dutifully trolled through a series of plasma views, labeled by frequency ranges, and stopped when it hit a softly ivory blob. Beth said, "Looks like a melted ice cream bar, three thousand kilometers across."
"That's plasma emission in the high microwaves," Cliff said, prowling up the energy scale in jumps. "Oblong—ah, look—in the low X-ray, there are a bunch of hard spots."
"Moving fast," Beth said as the refreshed image showed the luminous dots jumping along in flashes. "Seventeen. Fast! They're orbiting the brightest of them—which doesn't seem to move much. Look, one is fast, on an ellipse. The other makes a much smaller arc. A big guy with a swarm of bees around it. As though—good grief, they've got to have huge masses."
SunSeeker's ever-present Artilect conglomerate mind added on the screen, ONE IS MUCH LARGER THAN AN EARTH MASS ... APPROXIMATING ORBITAL PARAMETERS ... SMALLER, 0.73 EARTH MASS ... LARGEST 5.32 EARTH MASS. RADIUS OF THESE IS FAR SMALLER THAN THE RESOLUTION OF MY SYSTEMS.
"So they're less than a few hundred meters across," Cliff added.
All three looked at one another. "Black holes, then," Redwing said.