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.

The elevator fell rapidly. Fahy, clutching her softscreen and scribbled notes, almost stumbled, disoriented; it was like being back in the T-38 again, pulling Gs.

The MP was only a kid, she thought, surely younger than thirty. His blue eyes were black-rimmed, and she wondered if he’d had any sleep recently. He was probably as afraid as she was. More so, because he couldn’t understand as much of what was happening as she did.

On impulse, she asked: “What’s your name, son?”

He looked at her, puzzled. “Ma’am?” His vowels had the broad richness of a Texan. His hand, she noted, had gone automatically to the butt of his pistol.

“Never mind,” she said.

When she emerged from the elevator, she found herself facing a gigantic, intimidating logo: a shield, studded with stars; a stylized planet ringed by solid-looking orbital hoops, a simple delta-wing spacecraft overlaid before it. It was, Fahy knew, the shield of the Air Force Space Command.

The MP hurried her through steel-walled corridors. His heels clattered on the metallic floor, his gun always visible. Fahy had to half-run to keep up.

After a couple of turns she’d lost her orientation. The lighting came from dazzling, grey-white floods embedded in the ceilings, so that the illumination was colorless, flattening. Everyone she encountered looked deathly pale, as if drained of blood. There were no colors here, no smells. It was like being inside a huge machine. The rooms were crammed with information technology: huge wall-mounted softscreens, printers, telecommunications gear; earnest young Air Force officers, many of them bespectacled, labored at terminals.