Titan n-2

by Stephen Baxter

  Meanwhile, Angel was having one of his bad days. He raged around the hab module, frustrated at his inability to perform the simplest task unaided. He railed at the equipment, at the assholes at NASA who wouldn’t speak to them any more, at his crewmates.

  For all the difficulties his presence posed on even the simplest EVA, it was outside the cramped, battered, stale confines of the hab module that Angel seemed most stable. The opportunity to get him outside hadn’t come up for a couple of days, though, and now they were likely to be shut in through the eight-day Titan night. And already, Benacerraf thought, they were paying the price.

  She made a meal for Angel, and sat him down in the Apollo couches. He rambled about his life, his space missions, his career, his father, even his sexual experiences. She sat and endured.

  Listening to him was an easy safety valve.

  Rosenberg padded around them in house shoes improvised from Beta-cloth scraps, and got on with his work on the pump. He didn’t actually do anything to help her with Angel; it was clear that as far as Rosenberg was concerned, Angel was Benacerraf’s problem, a waste of resources who ought to be pushed out the airlock.

  It took Rosenberg two hours to get around to those anomalous samples.

  Then he came bustling in from the Spacelab, shouting about an immediate EVA.

  Benacerraf glanced uneasily at Angel. But he seemed to be heading into one of his inward-looking, passive phases. He was rocking to and fro in his couch, his right leg tapping rapidly, his head turning to and fro. She had learned to read Angel’s moods; if he stayed in this state, he was so shut-in it was beyond the power even of Rosenberg’s noisy, unstructured ranting to irritate him.

  Rosenberg was still talking about going out.

  “Slow down, Rosenberg,” she said. “You know we’ve avoided EVAs at night.”

  “I know,” he said. “I know. But this is exceptional. We have an opportunity, right now, and we don’t know when it will recur. We’ll miss out on it if we wait seven or eight days for the fucking sun to come up.”

  “What opportunity?”

  “Paula, I analysed those samples you brought back. The anomalous tholin, the bubbling—”

  “I remember.”

  “You know what I found, in the sample you took from within the bubble?” He grinned. “Guess.”

  “Don’t play games, Rosenberg.”

  “Methane,” he said. “Almost pure methane gas. You see?”

  She thought it over. “No. No, I don’t get it. The air is full of methane. We even produce it ourselves. Why should we care enough about methane to risk our necks out there in the dark?”

  “Because of where the methane comes from,” he said rapidly. “It has to be from an underground reservoir. There are probably pockets of methane scattered all through the bedrock ice, though not all so close to the surface… It has to be an intrusion of the magma, the deep ammonia-water, which is forcing that methane to the surface now. And if that’s so, the site you found is one of the best possibilities for finding traces of ammono-analogue biology. Short of dropping into the caldera on Othrys, we—”

  “Woah.” She held up her hands again. “Tell me slowly.”

  “I’m talking about life,Paula,” he said softly. “Titan life: life beyond Earth. That methane vent represents one of our best chances of detecting it. If we sit in here on our butts, we may miss it.” He was struggling to be patient, she saw. “Do you get it? I’m not interested in the methane for itself. I’m interested in the ammonia-water magma.”

  “Because—”

  “Because if we’re going to find life anywhere, ammonia-analogue life, it’s in the fluid of the ancient oceans. Where liquid ammonia is still available, as a solvent. And that’s bubbling up out of the ground, a couple of miles away.”

  Angel turned his ruined face to Rosenberg. “Titan life, huh. So, what use is that? Can we eat the shit?” He shook his head, mumbling irritably, and retreated inward to his crooning.

  “Actually,” Benacerraf said drily, “he has a point, Rosenberg. This is science, not survival. I don’t think we should put ourselves in a life-threatening situation for—”

  Rosenberg seemed to snap.

  She’d never seen him so angry. He came up and loomed over her, screaming at her. “This is precisely the reason we came to Titan in the first place. We have to be able to do more than sit around in here recycling Bill’s piss and waiting to die. Paula, either you come out with me now, or I go out there myself. Right now.” There were flecks of spittle on his lip, and behind his glasses his red-rimmed eyes were staring.

  She closed her eyes, and wished she was in her wardroom.

  She was sick of juggling them, these two assholes, both as difficult as each other in their ways, both demanding that she soak it all up, run their lives for them.

  …The news from Earth, sent up to them in digital packets by the last DSN dish at Goldstone, was there. More ecological decay, more flashpoint wars over crop failures and water shortages, more floods of refugees washing across the southern continents, more sabre-rattling between the Chinese and Maclachlan’s government. In a way, the Chinese issue scared her most. It was like the Cold War all over again. Except that she sensed those old bastards in Beijing meant it, in a way the Kremlin never had.

  Well, maybe they could actually do some good up here. Maybe news of life outside Earth might actually lift some hearts, down on the bleeding ground. As Rosenberg said, it was why they’d come here, after all.

  “You win, Rosenberg. We’ll go.”

  He backed off, trembling.

  “But,” she said evenly, “it had better be worth it.”

  Angel, blind face turning this way and that, cackled as he rocked.

  They stepped outside the orbiter, emerging into the pitch dark of a Titan night.

  Benacerraf insisted the two of them rope themselves together.

  Rosenberg laughed at her. “For Christ’s sake, Paula. The tholin out west is as flat as a pancake for miles. What are you expecting to happen?”

  She confronted him. “I don’t know. I’ve only taken a walk over a methane vent once before, and last time I didn’t know I was doing it. If we have to be out here at all, we take precautions. Take the damn rope, Rosenberg.”

  He made noises of disgust. But he knotted the rope around his waist.

  They set off into the deeper dark, north-westwards, preceded by circles of lamplight. Benacerraf led the way, trying to retrace her steps to the methane vent. The gumbo glistened, purple and black, in the white light of the lamps; it reminded Benacerraf of an open wound.

  Somehow, Benacerraf thought, it was harder to walk into the dark, with the gumbo sucking at her snowshoes, and only unmarked desolation ahead of her, beyond the circles of lamp light. Her imagination seemed to be populating the empty darkness with vague demons, and she felt a gathering dread at the thought of proceeding further.

  Perhaps, she thought with a stab of unwelcome sympathy, Bill Angel feels like this all the time: his isolation on this dead alien world compounded by being lost in the dark.

  After a couple of miles, she slowed. “It was about here.”

  Rosenberg cast about with his lamp. “The surface looks normal to me.” He started to unknot the rope at his waist. “We ought to separate,” he said. “We’ll halve the time it takes if we work independently. Now, if I take the—”

  “Keep the rope on, Rosenberg.”

  “Paula, that’s just not logical. It’s so inefficient.”

  “Keep the rope on, or we go back right now. I mean it, Rosenberg. Ammonia life or no ammonia life.”

  He groused like a kid. “Shit, Paula.” But he knotted the rope up again.

  They began to search, working in widening circles around their starting position, the rope stretched to its maximum extent, their lamps throwing elliptical patches across the glistening, sticky gumbo.

  It was more difficult than Benacerraf had expected; the colors of the gumbo were different in white, Ea
rth-like lamplight, and the color changes she’d observed before were obscured. Rosenberg took to using his infra-red vision. The resolution was poorer than with the naked eye, but perhaps he could detect the temperature changes associated with the methane vent.

  After a few minutes, Benacerraf found what looked like a series of small, circular craters, dug into the gumbo at her feet. When she looked more closely, she found the lamplight had deceived her, making her reverse the image in her mind’s eye; the “craters” were actually bubbles, pushing slowly up through the gumbo.

  “Rosenberg,” she breathed. “I think I have it.”

  He came over as fast as the gumbo would permit. He stood over the bubbling patch. “My God,” he said. “You’re right, Paula. We did it. What a discovery.”

  He unloaded his sampling gear from the pockets of his EMU. He took scrapings of the gumbo, and of the atmosphere within and above the methane bubbles. He assembled a hollow tube from sections, to take a core sample. He hoped that the lower levels of the core would contain materials soaked in liquid ammonia.

  Benacerraf worked patiently at the core, twisting the improvised handle at the top, coaxing the core into the ground. It was difficult even to hold the handle against the stiffness of her thick gloves. She could feel the unevenness of her gloves’ heating elements rubbing against her palm, and soon she thought her fingertips, where they were scraping against the material of her gloves, were starring to bleed.

  k took as much effort to drag the core out of the clinging ground as to insert it. When it was free, Rosenberg started to dismantle the core sections.

  A thunderous roar, deep bass, sounded through Benacerraf’s helmet. Benacerraf could feel deep vibrations, as though the source of the noise was right beneath her feet.

  Rosenberg said, “I think—”

  There was a boom, like a sonic shock.

  A few yards to Rosenberg’s right, a grey cloud was erupting. She turned that way to focus her lamp light. The cloud was droplets of gumbo, thrown up from the ground, subsiding slowly back to the surface.

  The ground had collapsed beneath the cloud, forming a roughly circular crater maybe six feet across. Benacerraf thought she could make out a gush of gas — methane, she guessed — pulsing out of the hole.

  “Holy shit,” Benacerraf breathed.

  “The whole area is unstable,” Rosenberg said quickly. He was still working on the core. “We’re on some kind of crust over big methane bubbles. The methane venting might become explosive.”

  Another shudder beneath Benacerraf’s feet. The ground shook again, and again. Another hole, bigger than the first, opened up to her right.

  “Let’s go, Rosenberg.”

  He was bending to the surface, scooping up the sections of the core sample. “I just need to collect this.”

  “Leave it, for Christ’s sake.”

  More crumps and bangs; the ground shuddered again. Rosenberg was still fussing with his samples.

  “Rosenberg! Move!” She tugged at the rope, yelling at him.

  He straightened up, clutching one core sample section which he shoved in a pocket of his EMU.

  They started to make their way back out of the vent area, stepping clumsily, casting their lamp light around. They followed their footsteps back out towards Tartarus; the footsteps showed up as a trail of shallow, infilling gumbo craters.

  A gush of methane erupted from the ice, just to Benacerraf’s left. She ducked. The noise was so all-engulfing it felt as if the sound was passing both underfoot and overhead.

  And then a crater, a distorted circle ten feet across and steaming with methane vapor, opened up between Benacerraf and Rosenberg. There seemed no limit to the depth of the craters in their lamplight, as if the exposed pits reached to the heart of the world.

  There was a feeling of hollowness beneath her; she thought she could hear echoes of the imploding ice and gumbo being returned from some huge chamber beneath her. She had the vertiginous feeling that she was crossing some fragile bridge, over a chasm.

  The randomness terrified her. With every step she half-expected a crater to open up beneath her, or Rosenberg. Either would probably be enough to kill them both.

  Proceeding cautiously, probing with their lamps, skirting places where the gumbo seemed to be bubbling, it took them an hour to cross a stretch of tholin that had taken five minutes on the way out.

  Rosenberg took more than a week, working in his miniature lab, to process the samples he brought back from the methane vent. Benacerraf didn’t disturb him; Rosenberg was reclusive to the point of secrecy about work in progress.

  But he didn’t look happy, as far as she could see.

  Eventually, after a few hours’ work in the CELSS farm in Apollo, she came into the hab module to find Rosenberg dictating into a softscreen.

  “…CH, CN and CC functional groups are evident in the imaginary part of the refractive index, as expected from the gas phase products that are the tholin precursors. Acid hydrolysis yields an array of racemic amino acids, both biological and non-biological, plus much urea. See Table Twelve. Amino acid yields are about one percent by mass of the tholin; their precursors appear to be formed by chain-addition reactions of the most abundant gas-phase species. Two-step laser mass spectrometry reveals ten to minus four grains per gram of two-four ring polycyclic aromatic hydrocarbons; larger amounts of higher PAHs may be present. The volatile component of the tholin was examined by sequential and nonsequential pyrolytic gas chromatography and mass spectrometry; over one hundred products were detected — Table Thirteen — including saturated and unsaturated aliphatic hydrocarbons, nitriles, PAHs, amines, pyrroles, pyrazines, pyridines, pyrimidines and adenine…”

  Benacerraf placed a hand on his shoulder. “Rosenberg,” she said. “Talk to me.”

  He broke off. Distracted, his thin face lined and unhappy, he shook his head. “Hell, Paula.” He went to the hab module’s galley and came back with a cup of water; they sat on Apollo couches, side by side.

  She was going to have to be patient, she knew, “Tell me.”

  “Look,” he said. “You know the theory. Maybe life formed here, in the ancient ammonia ocean. The ammono life would burn methane in nitrogen, producing ammonia and cyanogen, just as we burn sugars in oxygen and give off water and carbon dioxide. Maybe it still exists in the aqueous ammonia in the mantle. Or maybe it’s at least dormant in there, in some kind of spore, waiting to be revived.”

  “So…”

  “So I tried to stimulate biological activity in the mantle samples we brought back in that core sample.”

  “And?”

  He rubbed his face, looking defeated. “I found a lot of cyanogen. The stuff ammonia life would breathe out. More than you’d predict from straightforward physico-chemical processes. And a number of other products which I expected as ammono analogues of terrestrial biochemicals. Aminines, which correspond to fatty acids. Ammono-lipids, like ammotto-tristearin. Plenty of complex alpha-ammoamidines, analogues of alpha-amino acids. Carbohydrate analogues like polyaminopiperidines. Ammono-nucleic acids, like a guanine analogue. Actually, I’ve seen a lot of exotic chemistry here; we didn’t even know if such compounds would be chemically stable at these temperatures…”

  “My God,” she said. “If I understand all that, then you were right. Evidence of life.”

  “Yes,” he said. “But it’s all four billion years old.” He got out of his coach, stamped over to the lab area and came back with a small phial of muddy mantle material. “Paula, when I stimulated the organics in here with ammonia and nitrogen, there was no increase in the cyanogen concentration. The stuff is inert. Nothing is breathing.”

  “Then the ammono-biological products you found—”

  “They were fossils. Paula, there must have been ammono life here once, in the primeval oceans. It had hundreds of millions of years; perhaps it even reached a high degree of complexity. But it couldn’t survive the change, the freezing over of the ocean, the plummeting temperatures. All
that’s left now is what I found: chemical fossils, the decomposed elements of a life that was snuffed out billions of years ago. Just like that old rock from fucking Mars.

  “You called tholin the stuff of life.” Now he threw the sample to the floor of the hab module. It shattered, and its muddy contents splashed over the plastic. “You were wrong. There is only death here.”

  So, she thought, this is the end of Rosenberg’s dream: in a sense, the reason we all came here, beyond the geopolitics and the thwarted ambitions, and whatever personal flaws impelled us out of Earth’s atmosphere…

  Titan is dead. We’re orphans, in the Solar System. Now, there’s nothing left for us to do, but endure, and fear for Earth.

  The ancient ammonia bubbled, evaporating rapidly, and soon Benacerraf could smell its pungent stink.

  …Dead, she thought. Or maybe just deep-frozen?

  * * *

  As far as Barbara Fahy was concerned, it only took a couple of hours for the world to fall apart.

  She was summoned to Washington. She was to attend a hastily convened briefing on 2002OA with Hartle and other Air Force officers in the Batcave, the Space Command center buried deep beneath the streets of DC.

  She had to fly by T-38 — piloted by a sullen ex-astronaut — as air traffic control was out, it seemed, right across the continent, and civilian flights were grounded. As she flew over DC she could see the problems, even from the air: whole city blocks without power, fires burning uncontrolled in the poorer areas.

  The Chinese, it was whispered, were screwing with our computers. From here on, it looked as if the scuttlebutt was true.

  She was whisked by chopper to NASA Headquarters. There another car was waiting for her, and it took her a couple of blocks across town.

  The traffic was lousy. All the lights were out. The big softscreen billboards were all dead, too; they hung like black wings on the sides of the buildings lining her route. Even the little image-tattoos on the faces of the street kids had turned black, like burns.

  She arrived at another anonymous-looking Government building, and was hurried through heavy security and into an elevator. The elevator was just a box of steel, its surfaces polished. The security was tough even here: there were video cameras mounted on the walls, watching her, and an armed MP standing discreetly at the back of the car.