Ark

70

December 2051

Everybody crowded into Halivah for Venus’s crew report on Earth II, all save for a watch crew left over in Seba, and Holle knew that they too would be glued to the comms system. For her presentation Venus set up a crystal ball, a three-dimensional display unit that hadn’t been unpacked since they left Earth, that hummed and glistened as its panels rotated, too fast for the eye to follow. Holle knew this was a gift to the Ark from Thandie Jones, and was the very same piece of equipment Thandie had once used to brief the LaRei people in Denver, with Holle and Kelly running around on the floor, and she’d used it even before then in New York for the IPCC.

Holle herself found a place on a catwalk beside Kelly Kenzie. Venus had taken out the mesh panels over three decks to open up a kind of auditorium in the heart of the hull, so everybody could see and hear, and more than eighty people, including kids and babies, were jammed in, clinging to catwalks and ladders and waiting for the show. A rumble of excited conversation echoed, and there was a rare sense of crowd. Holle picked out familiar faces all around the chamber, the people with whom she had shared so much, in some cases since they were all children together in Denver. There was Mike Wetherbee standing by Zane Glemp, his most intractable yet his most valuable patient, and Theo Morell, the half-corrupt king of the HeadSpace booths, and the Shaughnessy brothers, solid hard workers both, Jack with a cap pulled down over his burn-scarred face, and Thomas Windrup and Elle Strekalov, still together despite all their tribulations, and Masayo Saito, the army lieutenant who, thrust into an impossible and unexpected position, had proven to be a bridge-builder of wisdom and courage, and poor Cora Robles who had never got over the loss of her little girl, a shadow of her old brilliant self-yet who was now pregnant again. Helen Gray, nine years old now, stood by her mother on a catwalk on the opposite side of the hull. She was playing pat-a-cake with six-year-old Steel Antoniadi. When she glimpsed Holle, Helen waved her hand. She was growing into a pretty kid with her mother’s very English coloring. It struck Holle that Helen had never seen as many people together as this in one space, not in her whole life. But Helen’s eyes were drawn, like the other children’s, to Venus’s glittering toy.

Holle felt a mood of exhilaration, of belonging. For all their triumphs and their tragedies, their weaknesses and their strengths, they had got here, across ten years since Gunnison and more than twenty light-years. They had reached 82 Eridani. And they had all seen the prize, Earth II, with their naked eyes. Venus had allowed the crew into her precious cupola, a few at a time, to gaze down on the huge world turning a few hundred kilometers beneath the orbiting Ark, with its creased oceans, scattered cloud, rusty landmasses. There was a sense of unity, at last; together they had achieved a mighty triumph.

But Earth II wasn’t what they had hoped for. And now, today, six months after the Ark’s arrival at 82 Eridani, they had grave decisions to make. Holle wondered how much of that wonderful unity would survive the day.

Wilson Argent came strutting across the deck, and the conversations hushed. Wilson looked around at the crew, on the decks and catwalks and clinging to the ladders. He was a big man, imposing and impressive. Three years after his takeover from Kelly his power over the crew was absolute, and he was regarded with a mixture of admiration, awe and fear. Today he had opened up for discussion the biggest decision they had had to make since leaving Earth, a decision about the whole future of the mission, the Ark; even he couldn’t railroad this. But as a result this decision day was a moment of comparative vulnerability for Wilson.

On impulse Holle glanced at Kelly. Her expression was hard, set. Holle recognized Kelly’s “ambitious” face, the face she had worn when she’d announced she was leaving her kid behind to keep her place on the Ark. Since he had ousted her, Wilson had always let Kelly alone, but at best they had been like two warring armies under an armed truce. Well, today Kelly looked like she was planning something, and Holle felt a stab of deep unease.

“You all know why we’re here.” Wilson’s voice, subtly amplified, boomed through the whole hull. “We achieved mankind’s first star flight, we reached Earth II, and we’ve all had one hell of a party. But the job’s not done yet-not until we’re down on the new ground, turning the turf and planting our first crops. Now Venus is going to summarize what we’ve learned so far about the planet. And then we’ll decide, as a group, what we’re going to do about it.” That was Wilson, blunt and to the point. He nodded to Venus and backed off to stand with the gang of illegals and gatecrashers who had gravitated to his court.

Venus stepped forward, looking around at the expectant faces. She tapped her handheld. The crystal ball flared with light, and an image of Earth II coalesced.

It was a sphere more than a meter across, turning slowly around a horizontal axis. It was bright and detailed, and its glow, blue and gray, brown and white, lit up the faces of the watching people. Venus stayed silent, giving them a few seconds to take it in. The last murmurs hushed.

Holle remembered the first blurred images of the new planet, images taken from light-years out and constructed with extraordinary care by Venus’s planet-finder technologies. This new mapping was as detailed as any image of Earth as seen from space she had ever seen. And the planet wasn’t simply some abstract entity any more; now, after their months in orbit, it was a world already replete with human names. They had tentatively labeled the rotation pole that was currently pointing at the sun as “north”; the world turned counterclockwise as seen by an observer above that pole. Subject to months of unbroken heat from 82 Eridani the pole was blanketed in cloud, with storms visibly spinning off a massive central swirl.

At lower latitudes Holle made out landmasses that were already familiar to everybody aboard. A big strip of land stretching north to south across the equator was “the Belt,” a kind of elderly Norway with deep-cut fjords incising thousands of kilometers of coastline. The northern half of the Belt was currently ice-free, but its southern half, stretching into the realm of shadow, was icebound, and snow patches reached as far north as the equator. Sprawling across a good portion of the eastern hemisphere was the roughly circular continent they called “the Frisbee,” a mass of rust red broken by the intense blue of lakes and lined by eroded mountains. Its center was dominated by a huge structure, a mountain with a base hundreds of kilometers across, and a fractured caldera at the top. The mount was so like Olympus Mons on Mars that giving it the same name had been unavoidable, and it so dominated the overall profile of the continent, giving it an immense but shallow bulge, that the nickname “Frisbee” was a good fit. Then, to the west of the Belt, an archipelago sprawled, a widespread group of islands, some as large as Britain or New Zealand, that they called “the Scatter.” There was one more continent at the south pole, currently plunged in darkness and buried under hundreds of meters of winter snow, called “the Cap.” The world ocean itself had no name yet; the seas could be named when they were ready to go sailing on them, Holle thought.

The most exciting features were the patches of purple at the coasts of the continents and the shores of the lakes: life, native life on Earth II, plants of some kind, busily using 82 Eridani’s light to turn carbon dioxide into oxygen with their own unique photosynthetic chemistry.

Venus began without preamble.

“You all have access to the full reports in the ship’s archive. Today I’m just going to summarize the key findings.

“We’ve been here in this system for six months. We’ve surveyed atmosphere, land and oceans spectroscopically at all wavelengths, and have used radar to probe the subsurface and to map the seabeds, and have also dropped a series of penetrating probes for direct ground-truth sampling.” These were landers like slim missiles, hardened to withstand violent impacts and to bury themselves a few meters beneath the surface, with ground cameras that gave a close-up view of the final stages of the descent, and equipped with seismometers, chemical sensors, thermal sensors, magnetometers.

“Here’s the good news,” Venus said. “Obviously we have a world of about the right mass and the right volatile inventory, orbiting in a stable circular orbit at about the right distance from its sun to allow stable water oceans on the surface. ‘Right’ meaning it’s Earthlike.

“And on a basic level it’s habitable. If you landed in one of the shuttles and stepped outside, you’d experience a gravity of about eighty percent of a G; Earth II is less massive than Earth, and smaller in radius. Right now the northern summer is somewhere near its midpoint. If you were to stand at the pole you’d see the sun circle close to the zenith, right above your head. At the equator the sun is circling around the horizon, maybe dipping below for a few hours a day, depending on exactly where you are. It’s cold, there’s snow on the ground, but it’s no worse than a winter day in one of Earth’s temperate zones.

“Where the sun is up you could walk around with no more protection than a decent coat, some strong boots, a face mask. You could expose your skin, at least from the point of view of the sun’s radiation; there’s a healthy ozone layer. You would need some protection from cosmic radiation; the planet’s magnetic field is a lot weaker than Earth’s. You could breathe the air, we believe. It’s basically a nitrogen-oxygen mix of about the same proportions as Earth’s atmosphere. In the early days you’ll be wearing a face mask, in case of trace toxins from geological or maybe biological sources.

“We know there’s life down there. Life at the microbial level and, it seems, at some kind of simple multiple-cell level, something like stromatolites maybe. That’s what puts the oxygen in the air. It’s unlikely it will harm us, unlikely our alien biochemistries will interact significantly, but we’ll have to check it out. We believe that once we establish some terrestrial soil down there, Earthlike flora will take a hold: our crops will grow, our animals, when we incubate them, will be able to feed. Our children will be able to run and play.” She got a scattering of applause for that: But there was no joy in her face.

“This much we were able to guess from observations from Earth and Jupiter,” she said. “But all we could see from the solar system was a blurry dot with some evidence of mass, orbit, atmospheric composition. That’s all. On that basis it looked promising. But as it’s turned out, Earth II is not that close a sister to Earth I.

“This is a much less active world than Earth, geologically. You can see that from the eroded chains of mountains, the flat landscapes. The penetrators’ seismometers have detected few earthquakes. And we see no significant evidence of continental drift, no active plate-forming mid-ocean ridges, no subduction zones at plate boundaries-no colliding plates to trigger volcanism and to throw up mountain chains, as on Earth.

“Tectonic shift has seized up, here. It’s not absent, but is clearly operating at a much reduced rate than on Earth. And the result is the geology we see. The Frisbee is not unlike Australia, ancient and stable, so old its mountains are worn down, the rocks shattered to dust and rusted red. The big volcano at the heart of the Frisbee is a shield volcano, like Hawaii on Earth, and just like Olympus Mons on Mars-we named it well. It’s been created by a magma plume, an upwelling of hot material from the planet’s mantle, like a fountain. Olympus has been stuck over that plume for a long time-hundreds of millions of years, maybe. Over similar periods on Earth, the continents slide all the way from equator to pole.

“Is that important? We think so, for the sake of the long-term habit-ability of the planet. On Earth, plate tectonics play a key part in the vast geological and biological cycling that maintains Gaia. This world, with tectonic processes much reduced, can’t sustain such a significant cargo of life.

“Why has Earth II turned out to be so much less active than Earth? First, Earth II is that much smaller than Earth. Like Mars, it must have shed a greater proportion of its interior heat of formation, and a greater proportion of its inventory of radioactive materials will have decayed away. So the big internal heat engine that drives plate tectonics has run down. And second, we believe Earth II is actually an older world than Earth, by a billion years or more; whatever triggered planet-forming in this system happened much earlier than back home.”

Wilson put in, “So a billion years ago this world might have looked that much more like Earth.”

“Yes. With a much richer biosphere. I think we can expect to find traces of past complexity, lost as the planet has run down. That may be why we see no traces of extant intelligence.”

Kelly seized on that word. “ ‘Extant’? Does that imply you found traces of nonextant cultures?”

Holle felt unreasonably excited.

For answer, Venus tapped a handheld.

The turning world winked out of existence, to be replaced by an image of one of the larger islands of the Scatter, as if seen from a low-flying aircraft. Once it may have been mountainous; now its mountains were worn to stubs. “We call this Little Jamaica.” Venus pointed to features on a plain close to the sea. “Can you see?” There were faint circles, hints of straight-line features. “We don’t know what this is. You need to remember that this island is covered by the pack ice every local winter; any traces of surface structures, of buildings and cities, would long ago have been destroyed. It could be the trace of a quarry, we think. That might survive as long as a billion years. Maybe it’s something else, like a city. There are other indicators of intelligence. We’ve found no evidence of deep-buried carbon deposits. If there was any oil or coal on this world, or the local equivalent, it’s long gone. No evidence of particularly rich seams of mineral ores near the surface. A paucity of asteroids in this system, too.”

Wilson folded his arms. “I don’t get it. These are indicators of what?”

“That somebody used up the easily available resources-the oil, the easily mined ores, even off-world resources in the asteroids. And then they died out, or went away. We might find direct evidence one way or the other when we start doing some real archaeology down on the surface.” She shrugged. “There’s a lot of sand to sift.”

“My God,” Holle whispered.

“I know,” Kelly said. “It’s not good for us. But isn’t it wonderful?” And, just for a moment, it was as if they were Candidates again, marveling together over some wondrous bit of scholarship. But they weren’t here for scholarship today.

Somebody called, “And what about the obliquity? I thought that was the big problem.”

Venus allowed herself a rueful smile. “I was saving the best until last.”

She brought up a fresh display. This showed Earth II and its sun, 82 Eridani. The diagram wasn’t to scale, planet and star looking like two light-bulbs, and the planet’s orbit was a glowing yellow circle around the sun. The planet’s rotation axis showed as a glowing splinter pushed through its bulk, a splinter that pointed almost directly at the sun.

Venus said, “As the planet goes around the sun, the axis keeps pointing the same way-just as for Earth. You can see the consequences.” She tapped a key and the planet zipped around its star, keeping its axis pointing in the same direction in space. Earth II’s year was about the same as Earth’s, so after six months the north pole would be plunged into shadow, while its south pole was in the light. “Earth’s obliquity, the tilt of its axis, is about twenty-three degrees, compared to Earth II’s ninety. Life on Earth evolved to cope with moderate seasonality. Here you have the most severe seasonality you can imagine.

“Every part of the planet except an equatorial strip will suffer months of perpetual darkness, months of perpetual light. Away from the equator you’ll suffer extreme heat, aridity, followed by months of Arctic cold-we estimate the surface temperature will drop to a hundred degrees below across much of the space-facing hemisphere, and there’ll be one hell of a blanket of snow and ice. Even the equator would be a challenge to inhabit, for even at the height of summer in either hemisphere the sun would be low, the heat budget minimal, the climate wintry.”

Venus restored the image of the planet, the tilted-over world with its friendly looking continents. Now she made the image accelerate through a simulation of its seasonal cycles. Ice crusted the continents, only to clear and leave them desiccated, brick red. “We can’t survive this,” she said. “Oh, maybe we could adapt to one extreme or another. But not to these swings, year on year, from baking aridity to an Antarctic chill. Our plants, our animals, couldn’t cope with it either. The only possible habitation would be on the equator, but there’s very little equatorial land, a few islands and a slice of the Belt… We lucked out. We couldn’t see the rotation axis from Earth. We couldn’t have predicted these features.”

She fell silent. Her audience, in silence save for the wriggles of children, gloomily watched as her toy planet suffered its cycling seasons.

Theo Morell surprised Holle by calling down, “You say this wasn’t visible from the Earth. OK. But you must have been aware of some of these problems, particularly the axis thing, from further out. You’ve spent the last ten years looking out of that cupola of yours.”

“Yes, I-”

“When did you know Earth II was going to be a bust?”

Venus glanced at Wilson, who shrugged and looked away. “Around two years ago. The data started hardening then-we’d had some suspicions. Two years ago I was sure enough to take it to Wilson, for instance.”

Mentioning Wilson was a way to bring herself into his protection, Holle realized. But the mood in the chamber was switching, through shock and disappointment to a kind of anger. Theo shouted, “And you kept them a secret, these ‘suspicions’ of yours?”

Wilson stepped in. “That was all we had. Suspicions. We needed to get here to confirm it all. And besides, we couldn’t exactly change course. You know that you can’t control a warp bubble from the inside. Now is the right time to deal with this, and here we are doing just that, everything out in the open.” He turned to Venus. “You still have the floor. What do you recommend?”

She looked up, her face set. “That we can’t live here, on Earth II. The journey isn’t over. We have to go on. Sorry, but that’s it.”

There was a moment of shocked silence. Then people started shouting, pointing at Venus as she stood defiantly by her model, surely wishing she was back in the sanctuary of her cupola.

We have to go on, Venus had said. But, Holle wondered, thrilled and awed, go on to where?