The Nereidium Montes popped over the horizon ahead. Mars had never had much tectonic movement, and so mountain ranges were rare; those that existed tended to be crater rims writ large, rings of ejecta thrown out by impacts so great that the debris fell in two or three concentric ranges, each many kilometers wide, and extremely rugged. Hellas and Argyre, being the biggest basins, therefore had the biggest ranges; and the only other major mountain range, the Phlegra Montes on the slope of Elysium, was probably the fragmentary remains of a basin impact later inundated by the Elysium volcanoes, or by an ancient Oceanus Borealis. Debate raged over that question, and Ann, John’s final authority in such matters, had never expressed an opinion on it.
The Nereidium Montes made up the northern rim around Argyre, but currently Ann and her team were investigating the southern rim, the Charitum Montes. Boone adjusted his course southward, and in the early afternoon he soared low over the broad flat plain of the Argyre Basin. After the wild cratering of the highlands, the basin floor seemed smooth indeed, a flat yellowish plain bounded by the big curve of rim ridges. From his vantage he could see about ninety degrees of the arc of the rim, enough to give him a sense of the size of the impact that had formed Argyre; it was an amazing sight. Flying over thousands of Martian craters had given Boone a sense of the sizes they came in, and Argyre was simply off the scale; a quite big crater named Galle was no more than a pockmark in Argyre’s rim! A whole world must have crashed in here! Or, at the very least, a damn big asteroid.
Inside the southeast curve of the rim, on the basin floor against the foothills of the Charitum, he spotted the thin white line of a landing strip. Easy to spot human constructs in such desolation, their regularity stood out like a beacon. Thermals were rising hard off the sunwarmed hills, and he turned down into one, dropping with a vibratory humm, the craft’s wings bouncing visibly as it stopped. Dropping like a rock, like that asteroid, John thought with a grin, and he pulled up for the landing with a dramatic last flourish, putting down with as much precision as he could muster, aware of his reputation as a hot flyer, which of course had to be reinforced at every opportunity. Part of the job …
But it turned out there were only two people in the trailers by the strip, and neither of them had watched him land. They were inside watching TV news from Earth; they looked up when he came in the inner lock door, and jumped to their feet to greet him. Ann was up one of the mountain canyons with a team, they told him, probably no more than two hours’ drive away. John ate lunch with them, two Brit women with North accents, very tough and charming; then he took a rover and followed the tracks up a cleft into the Charitum. An hour’s twisting climb up a flat-bottomed arroyo brought him to a mobile trailer, with three rovers parked outside it. Together they gave it the look of a desiccated cafe in the Mojave.
The trailer was unoccupied. Footprints led away from the camp in many directions. After thinking it over Boone climbed a knoll west of camp, and sat down on its peak. He lay on the rock and slept until the cold penetrated his walker. Then he sat up and tongued a capsule of omegendorph, and watched the black shadows of the hills creep east. He thought about what had happened at Senzeni Na, running through his memories of the hours before and after the accident, the looks on people’s faces, what they had said. The image of the falling truck gave his pulse a little surge.
Copper figures appeared in a cleft between hills to the west. He stood and descended the knoll, and met them down at the trailer.
“What are you doing here?” Ann said over the first hundred’s band.
“I want to talk.”
She grunted and switched off.
The trailer would have been a bit crowded even without him. They sat in the main room knee-to-knee, while Simon Frazier heated spaghetti sauce and boiled water for pasta in the little kitchen nook. The trailer’s sole window faced east, and as they ate they watched the shadow of the mountains stretch out over the floor of the great basin. John had brought along a half-liter bottle of Utopian cognac, and he broke it out after dinner to moans of approval. As the areologists sipped he cleaned the dishes (“I want to”) and asked how their investigation was going. They were looking for evidence of ancient glacial episodes, which if found would support a model of the planet’s early history that included oceans filling the low spots.
But Ann, John thought as he listened to them; would she want to find evidence of an oceanic past? It was a model that tended to lend moral support to the terraforming project, implying as it did that they were only restoring an earlier state of things. So probably she would not want to find any such evidence. Would that disinclination bias her work? Well, sure. If not consciously, then deeper. Consciousness was just a thin lithosphere over a big hot core, after all. Detectives had to remember that.
But everyone in the trailer seemed to agree that they weren’t finding any evidence for glaciation, and they were all good areologists. There were high basins that resembled cirques, and high valleys with the classic U-shape of glacial valleys, and some dome-and-wall configurations that might have been the result of glacial plucking; all these features had been seen in satellite photos, along with one or two bright flashes that some people had thought might be reflections from glacial polish. But on the ground none of it was holding up. They had found no glacial polish, even in the most wind-protected sections of the U-shaped valleys; no moraines, lateral or terminal; no signs of plucking, or of transition lines where nanatuks would have stuck out of even the highest levels of ancient ice. Nothing. It was another case of what they called sky areology, which had a history going back to the early satellite photos, and even to the telescopes. The canals had been sky areology; and many more bad hypotheses had been formulated in the same way, hypotheses that were only now being tested with the rigor of ground areology. Most collapsed under the weight of surface data, got tossed in the canal as they said.
The glacial theory, however, and the oceanic model of which it was part, had always been more persistent than most. First, because almost every model of the planet’s formation indicated that there should have been a lot of water outgassing, and it had to have gone somewhere. And second, John thought, because there were a lot of people who would be comforted if the oceanic model were true; they would feel less uneasy about the morality of terraforming. Opponents to terraforming, therefore … No, he was not surprised that Ann’s team was not finding anything. Feeling the cognac a bit, and irritated by her unfriendliness, he said from the kitchen, “But if there were glaciers the most recent would have been, what, a billion years ago? That much time would take care of any of the superficial signs, I should think, glacial polish or moraines or nanatuks. Leaving nothing but the gross landforms, which is what you have. Right?”
Ann had been silent, but now she said, “The landforms aren’t unique to glaciation. All of them are common in Martian ranges, because they were all formed by rock falling out of the sky. Every kind of formation you can think of is out here somewhere, bizarre shapes limited only by the angle of repose.” She had refused any cognac, which surprised John, and now she stared at the floor with a disgusted look.
“Not U-shaped valleys, surely,” John said.
“Yes, U-shaped valleys too.”
“The problem is that the oceanic model isn’t very falsifiable,” Simon said quietly. “You can keep failing to find good evidence for it, and we are, but that doesn’t disprove it.”
The kitchen clean, John asked Ann to go out for a sunset walk. She hesitated, unwilling; but it was one of her rituals and everyone knew it, and with a quick grimace and a hard glance she agreed.
Once outside he led her up to the same peak he had napped on. The sky was a plum colored arch over the black serrated ridges surrounding them, and stars were popping into existence in a flood, hundreds per eyeblink. He stood by her side; she stared away from him. The ragged skyline might have been a scene from Earth. She was a bit taller than him, a gaunt, angular silhouette. John liked her, but whatever reciprocal liking she may have had for him – and they had had some good talks in years past – had dissipated when he chose to work with Sax. He could have done anything he liked, her hard looks said, and yet he had chosen terraforming.
Well,