Elizabeth Bear - Worldwired

Leslie's laughter almost sounded real. Then they'd bloody well better start shipping up some fucking beer.

Charlie snorted, fogging the inside of his helmet, and rolled his eyes as he switched on the climate control. “All ready back here,” he said, out loud, so Peterson could hear him.

“Right,” she said. “We're going in.”

The shiptree grew slowly and steadily in size as they slid up on it. Charlie already knew the lights weren't portholes. Like all the contact team, he'd studied telescopic images and the data from the unmanned probes. He knew that the hull of the vast structure — the autonomous space-faring vegetable, as he had described the hulk he and Fred Valens had explored on Mars — was comprised of a substance not all that different from cellulose reinforced with monofilamental carbon fiber. Buckytubes: the same substance that had been engineered to make the beanstalks possible — but the buckytubes in the shiptree's hull were grown, theoretically, not manufactured.

Unless the nanosurgeons had built them, reworking the Brobdingnagian shape from whatever it had once been, into a starship. Always a possibility.

And in another fascinating twist, the conductive carbon filaments in the shiptree's hull were sheathed in a substance analogous to myelin, and interconnected via organic transistors — carbon filament diodes, which Gabe said were nearly identical to the ones used in humanity's own early experiments with nanochips, before the Benefactor tech had rendered Earth's nanomachine research obsolete.

Charlie's hands closed on the arms of his acceleration couch, the jointed gauntlets pressing creases into the flesh of his fingers as the Gordon Lightfoot braked on a long smooth arc and came about, paralleling the kilometers-long hull of the shiptree. Firefly green and neon-tetra blue, the lights rippled in response to the passage of the smaller ship.

“Do you suppose she's hailing us?” Jeremy, his voice dulled and echoing through the helmet. He hadn't turned on his radio.

“It's as good a guess as any,” Charlie answered. “I think that's bioluminescence, which means that it's likely either for communication or for luring prey. Of course, a critter evolved for space would find light an efficient signal.”

“You don't think the ship is the intelligence, do you?”

Charlie shrugged. “Why not? It's possible, and it shows up in enough science fiction that way. The one we found on Mars looked like it had something very much like the VR cables our pilots use, though. Admittedly…”

Richard's voice, through external speakers so Jeremy and Peterson could hear him. “Those ships were so many eons old that we can only speculate how much the species that designed them have changed.”

“My thoughts exactly.” Thank you, Dick.

Jeremy nodded inside his helmet, and started talking before Charlie could remind him to speak out loud. “Well, which leaves us with the following question. They — it — never exhibited any kind of semaphoring behavior at the unmanned probes. Do you think it knows we're out here?”

“I can feel them,” Charlie said. “It stands to reason that they can feel me.”

“And the probes didn't have red and green running lights,” Leslie added, over the speakers rather than inside Charlie's head. “If we're theorizing that the shiptree uses bioluminescence to communicate, and its lights are all at the green and blue and indigo end of the spectrum, maybe it's seeing the Gordon Lightfoot 's green running lights as a friendly wave hi.”

“You never thought to shine a spotlight on it?” Charlie couldn't be quite sure, but he was reasonably sure that Jeremy was rolling his eyes.

“I'm a biologist,” Charlie said. “This is why we hired you guys.” He craned his neck to get a better look at the whorled shell gliding by under the Gordon Lightfoot 's floodlights, emerging from darkness before and disappearing into darkness again behind, outlined by its own rippling glow and the trembling silver-gray threads of whatever it was that trailed off the smooth hull between them. It was like the hulk of some long-submerged wreck revealed and then vanishing in the lights of an exploratory submarine. He could have seen it more plainly in the holoscreens, but there was something about the evidence of his own eyes that tightened his throat and made breathing an effort.

“Lieutenant,” Jeremy said, “can you dim our lights?”

“Dim them? Or shut them off?”

“Well, all the way off. But just flash them a few times.”

“Damn, look at that thing; it's got no symmetry at all, not bilateral or radial. It's just kind of there.”

“It's got a fractal pattern, though,” Richard pointed out. “The smaller whorls build to larger whorls and then larger ones. The whole thing looks like a giant toboggan if you squint at it.”

“How are you managing to squint, Dick?” Charlie shot back, drawing a laugh from Jeremy. The AI was right, though. It was as apt a description as the one that had come to Charlie, of water-worn driftwood. “You know what it reminds me of?”

“Coral,” Jeremy said promptly, and Dick said “Gypsum crystals, only curved.”

“Ready to flash lights.”

“Thank you, Lieutenant.” Charlie strained against his restraints to get a better look.

The sudden darkness in the Gordon Lightfoot , inside and out, was shocking. The cabin lights went out, followed — Charlie presumed, unable to see for himself — by the running lights lining her sides. Isolated in his suit, Charlie counted breaths, counted heartbeats. He could feel Richard and Leslie, feel Jeremy and Peterson in the cockpit of the shuttle, feel his suit and the trickle of cool air into his helmet, and none of it meant a thing beside the… weight of the shiptree, its presence, like an enormous silent breathing beast in the darkness alongside the fragile bubble of the Gordon Lightfoot .

The darkness lasted three heartbeats. Peterson flashed the shuttle's lights once, twice, a third time… and then left them on, and Charlie drew a single tremulous breath.

For a moment, the shiptree hung shimmering in space, silent and lovely, quiescent as a slumbering dragon. Until, without warning, the entire length of the strange curved hull went dark.

“Damn,” Jeremy said.

Peterson killed the lights of the shuttle again, before Charlie could suggest it. “I hope that thing doesn't move on me,” she murmured in a soft, strained voice. Charlie wouldn't be surprised if she hadn't meant to say it aloud. And then she whispered, “ Holy… ” as a dim sunlit glow irised into existence on the shiptree's hull, an aperture like a focusing eye.

“What the bloody hell is that?” said Jeremy, and Charlie grinned in the dark, because the glow illuminated a puff of vapor dispersing into darkness.

“It's an air lock,” Peterson said.

“It's an air lock,” Charlie echoed, a second later. “And the atmosphere inside has water vapor in it, and maybe carbon dioxide and oxygen. Would you look at that? Somebody lives in there, boys and girls. Somebody lives in there .”

“It's bloody beautiful,” Leslie commented from the speakers. The shiptree's lights winked back at them, blue and green and teal, and, with a sigh Charlie couldn't interpret, Peterson illuminated the shuttle.

“We can't dock,” she said.

“No. EVA. Safer, anyway, since we won't share any atmosphere with the shiptree that way, and we'll get a nice vacuum bath coming and going.”

“Is that wise?” Jeremy asked.

Charlie shrugged, even though Jeremy couldn't see it. “It's what we came here to do. And I think they just invited us in.”

Jeremy calibrated the atmospheric sampler while Charlie checked the swabs and plates in his test kit. And if alien bugs don't like the taste of agar?