And went down in the ships, standing on tongues of fire, down to the west coast of the island they called Greenland. Its tip pointed at Aurora's north pole, but the shape of the landmass was very like, they said. Actually the match was approximate at best, a .72 isomorphy on the Klein scale. Nevertheless, Greenland it was.

Its rock was mostly black dolerite, smoothed flat by the ice of an ice age. The ferries carrying people landed near its west coast without incident, close to the robotic landers they had sent down previously.

In the ship almost everyone gathered in their town squares and watched the landings on big screens, either in silence or raucously; it was different town by town. Whatever the reaction, almost everyone's attention was fixed on the screens. Soon they would all be down there, except for a rotating maintenance crew that would keep the ship running. Other than those people, everyone was to live on Aurora. This was good, because almost everyone who expressed an opinion said they wanted to go down. Some confessed they were afraid; a few even said they had no interest in going down, that they were content in the ship. Who needed bare rock, on a lifeless moon, on the shore of an empty sea, when they already had this world they had lived in all their lives?

Some asked this, but most then answered, I do.

And so they watched the landings on their town screens with an intensity nothing else had ever inspired. Median heart rate, 110 beats a minute. A new world, a new life, a new solar system they intended to inhabit, to terraform and give to all the generations that would follow. Culmination of a voyage that had begun on the savannah more than a hundred thousand years before. New beginning of a new history, new beginning of time itself: Day One, Year Zero. A0.1.

In ship time, 170.040.

Freya's friend Euan was in the first landing crew, and Freya watched for him on the screens, and listened to his feed as he talked his way around the little shelter already there on the surface next to the landed ferries. Everyone in the landing party was transmitting to family, friends, town, biome, ship. Euan's voice was lower in tone than when he was a boy, but otherwise he sounded just as he had when they were kids in Nova Scotia: excited, knowing. It was as if he expected to see more than anyone else down there. The sound of his voice made Freya smile. She didn't know how he had gotten into the first crew to go down, but on the other hand, he had been good at getting into things he wanted to get into. Crews had been selected by lottery from among those trained to the various landing and setup jobs, and he had no doubt passed the tests to determine who was competent to the tasks involved. Whether he had rigged the lottery too, she could not be sure. She kept her earbud tuned to his voice-over in particular. All in the landing party were talking to people up in the ship.

Planet E's orbit was .55 AU in radius, closer to Tau Ceti than Venus was to Sol, but Tau Ceti emits only 55 percent of the luminosity of Sol, so E and E's moon were receiving 1.71 times as much stellar radiation as Earth, while Venus receives 1.91 times as much. E's moon, now called Aurora by everyone, orbited in a tidally locked, nearly circular orbit of E, at an average distance of 286,000 kilometers. E's mass created a gravity of 3.58 g; Aurora's was .83 g. This was the main reason they were going to try to occupy Aurora rather than E, which, though it fell in the class called "large Earth," was too large, or to put it more precisely, had too strong a gravitational pull at the surface, for their rockets to launch off it, let alone for them to feel comfortable or even to survive.

Aurora received light both directly from Tau Ceti and by way of a powerful reflection of Tau Ceti's light from the surface of E. This reflected sunlight (taulight?) was significant. Jupiter, for comparison, reflects about 33 percent of the solar radiation that hits it, and E's albedo was almost as great as Jupiter's. The sunlit part of E was therefore quite bright in Aurora's sky, whether seen by day or night.

The surface of Aurora therefore experienced a complicated pattern of illumination. And because it was tidally locked to E, as Luna is to Earth, the pattern was different for the E-facing hemisphere and the hemisphere always facing away from E.

The hemisphere facing away from E had a simple pattern: its days and nights lasted nine days each, the day always full sunlight, the night fully dark, being starlit only; and never a sighting of E at all.

The hemisphere facing E had a more complicated pattern: its nine-day-long solar night included a very considerable amount of reflected sunlight from E, which always hung in the same spot in the sky, different spots from different parts of Aurora, but always fixed, while going through its phases. Nights on the E-facing hemisphere of Aurora saw E go from quarter phase (circle half illuminated) to full moon around midnight, waning to quarter phase again near dawn. Thus there was always significant E light during this side of Aurora's solar night. The darkest time in this hemisphere actually came at noon during its solar day, when E eclipsed Tau Ceti, so there was neither taulight nor E light on the part of Aurora that was eclipsed, which was a very broad band across the middle latitudes.

There were also narrow libration lunes at the border of the two hemispheres of Aurora, in which E, while it went through its phases, rose and dipped just above or below the horizon. This libration rocking happened everywhere of course, but it was not so easy to see when it was high in the sky against the always shifting background of stars.

Possibly a diagram would make this regime clearer, but the analogy of Luna to Earth may help to make things comprehensible, as long as it is kept in mind that from Aurora, E seemed much larger in the sky, bulking about ten times larger than Earth seen from Luna; and because its albedo was high and it received 1.71 of Earth's insolation, it was much brighter as well. Big, bright, and from wherever one stood on the E-facing hemisphere of Aurora, always fixed in the same spot in the sky, granting a slight libration shift. At their landing site, this spot was almost directly overhead, only a bit south and east of the zenith: a big glowing ball of a planet, waxing and waning slowly. "When we learn the phases, we'll be able to use it like a clock," Euan said to Freya. "A clock or a calendar, I don't know which to call it. The day and the month are the same thing here. Whatever we end up calling it, it's not a unit of time we had on the ship."

"Yes we did," Freya said to him. "Women's periods. We brought the months with us."

"Ah yes, I guess we did. Well, now they're back in the sky again. But only eighteen days long. Wonder if that's going to mess things up."

"We'll find out."

They had chosen to land on Greenland partly because it was in the hemisphere facing E. Someone said that if one were standing on E looking up at Aurora, Greenland would have been located on the disk of Aurora about where a tear would leave the left eye of the man in the moon, on Luna as seen from Earth. A nice analogy.

The complicated regime of light on Aurora created very strong winds in its atmosphere, and the waves on its ocean surface were therefore often very large too. These waves had a very long fetch, indeed in some latitudes they never encountered land at all, but ran around the world without obstruction, and always under the pull of .83 g, so that they often reached a very large amplitude, well over 100 meters trough to crest, with the crests a kilometer apart. These waves were bigger than any that ever occurred on Earth, except in tsunamis. And since they never went away, during the nine-day nights the ocean surface froze over only in certain bays, and in the lee of various islands. When the time came for people on Aurora to take to the ocean, a time many spoke of enthusiastically, the seafaring would involve considerable challenges.

"So, now we're about to go outside the station," Euan said into his helmet speaker. Within the ship, 287 people were listening to his feed, while 1,814 people listened to other members of the landing expedition now leaving the station. 170.043, A0.3.

"Suited up, the suits are pretty flexible and light. Good heads-up display in the faceplate, and the helmet's a clear bubble, at least all of it I can see, so it feels fine to have it on. The g feels just like on the ship, and the air outside is clear. Looks like it might be windy, although I don't know why I say that. I guess I'm hearing it pass over the station buildings, maybe the rocks too. We're far enough from the sea that it isn't visible from here, but I hope we'll be taking the car west until we get to the bay west of here and can have a look at the ocean. Andree, are you ready to go? All right, we're all ready."

Six of them were going out, to check on the robotic landers and the vehicles that were ready to drive. If the cars were good, they would take a drive west to the coast, five kilometers away.

"Ha-ha," Euan said.

Freya settled down to listen to him and watch the view from his helmet cam.

"Now we're outside, on the surface. Feels the same as in the ship, to tell the truth. Wow, the light is bright!"

He looked up, and the camera view of the sky flared with Tau Ceti's light, then reduced it with filters and polarization to a round brilliance, big in the royal blue sky- "Oh wow, I looked at it too long, I've got an afterimage, it's red, or red and green both at once, swimming around. Hope I didn't hurt my retinas there! I won't do that again. I thought the faceplate would do better at filtering. It's going away a little. Good. All right, lesson learned. Don't look at the sun. Better to look at E, wow. What a giant round thing in the sky. Right now the lit part is a thick crescent, although I can see the dark side of it perfectly well too, I wonder if that comes through in the camera. I can see cloud patterns too, just as easy as can be. It looks like a big front is covering most of the dark part, sweeping into the part that's lit. I've got a double shadow under me, although the shadow cast by E light is pretty dim- "Wow, that was really a gust! It's very windy. There's nothing to show it here, the rocks are just sitting there, and I'm not seeing any dust blowing. The horizon is a long way off."

He turned in a circle, and his audience saw flat ground in every direction. Bare black rock with a reddish tint, striated with shallowly etched lines. Like the burren, someone said, a part of Ireland where an ice cap had slid over flat rock and stripped anything loose away, leaving long, narrow troughs that crisscrossed the rock.

"It's never this windy on the ship. Do these suits gauge wind speeds? Yes. Sixty-six kilometers an hour, it says. Wow. It's enough to feel like you're getting shoved by an invisible person. Kind of a rude person at that."

He laughed. The others with him started laughing too, falling into each other, holding on to each other. Aside from their shenanigans, there were no visible signs of the wind. Cirrus clouds marked the sky, which was either a royal blue or a dark violet. The cirrus clouds seemed to hold steady in place, despite the wind. Atmospheric pressure at the surface was 736 millibars, so approximately equivalent to around 2,000 meters above sea level on Earth, though here they were only 34.6 meters above Aurora's sea level. The wind was stronger than any they had experienced in the ship by at least 20 kilometers per hour.

The surface vehicle they had had charged batteries as expected, so they climbed into it and rolled off west. The light from Tau Ceti blazed off the rock ahead of them. From time to time they had to make a detour around shallow troughs (grabens?), but by and large their route was straightforwardly westward, as most of the troughs also ran east and west. Their helmet-camera views jounced only a little from time to time, as their vehicle had shock absorbers. The explorers laughed at the occasionally bumpy ride. There was nothing like this on the ship either.

Maybe there was nothing on the ship that was quite like what they were experiencing now. As a gestalt experience it had to be new. The horizon from their vantage point, about three meters above the ground, was many kilometers off; it was hard for them to say how many, but they guessed about ten kilometers away, much the same as it would have been on Earth, which made sense. Aurora's diameter was 102 percent Earth's; its gravity was only .83 g because Aurora was less dense than Earth.

"Ah look at that!" Euan cried out, and everyone else in the car exclaimed something also.

They had come within sight of Aurora's ocean. Lying to the west in the late afternoon light, it looked like an immense bronze plate, lined by waves that were black by contrast. By the time they reached a short cliff over the sea's edge, the plate of ocean had shifted in color from wrinkled bronze to a silver-and-cobalt mesh, and the lines of waves were visibly white-capped by a fierce onshore wind. They exclaimed at the scene, their cacophony impossible to understand. Euan himself kept saying, "Oh my. Oh my. Will you look at that. Will you look at that." Even in the ship many people cried out in amazement.

The explorers got out of the car and wandered the cliff's edge. Fortunately, when the wind caught them and threw them off balance, it was always inland and away from the cliff.

The cliff's edge was about twenty meters above the ocean. Offshore, waves broke to white crashing walls, which came rolling in with a low roar that could be heard through the explorers' helmets, always there under the keening of the wind over the rocks. The waves crashed into the black cliff below them, flinging spray up into the air, after which masses of white water surged back out to sea. The wind dashed most of the spray into the rocks of the cliff, although a thick variable mist also rose over the cliff's edge and was immediately thrown over them to the east.

The explorers staggered around in the wind, which was now so very visible because of the flying spray and the ocean's torn surface. Wave after wave broke offshore and was flatted to white as it rolled in, leaving trails of foam behind each broken white wall. The backwash from the cliffs headed back out in arcs that ran into the incoming breakers; when they crashed together, great plumes of spray were tossed up into the wind, to be thrown again in toward the land. It was a big and complex view, brilliantly lit, violently moving, and, as everyone could hear by way of the microphones on the explorers' helmets, extremely loud. Here at this moment, Aurora roared, howled, boomed, shrieked, whistled.

One of the explorers was bowled over, crawled around, got onto hands and knees, then stood up, carefully balancing, facing into the wind and stepping back quickly four or five times, swinging arms, ducking forward to hold position. They were all laughing.

It was a question what they would be able to do on such a windy world, Freya remarked to Badim, if it stayed that windy all the time. She added that it was more the ghost of Devi worrying in her than she herself. She herself wanted to get down there as soon as possible and feel that wind.

Meanwhile, down on Aurora, they were getting the construction robots started in their various tasks. A very slow sunset gave way to a night illuminated by the waxing light of E, always overhead. E's light diffused to a glow in the air somewhat like a faint white mist, which the settlers found they could see well in. The sky did not go black but rather stayed a lambent indigo, and only a few stars were visible.

The dolerite of Greenland was obdurate and uniform, containing not much in the way of other more useful minerals. They would have to hunt for those, but in the meantime, it was dolerite they had to work with. Many construction vehicles grumbled around cutting blocks of dolerite from the side of grabens, and stacking them in a wind wall to shield their little collection of landers. There was an almost continuous whine of diamond-edged circular saws. Meanwhile a smelter was extracting aluminum from crushed dolerite, which in this area proved to be about half a percent aluminum in composition. Other robotic factories were sheeting this extracted aluminum for roofs, rodding it for beams, and so on. A few of the robot excavators were set to drilling in a graben with a gravitational bolide under it, in the hope of locating some iron ore to mine. But for the most part, until they found some areas of different mineral composition, they were going to have to work with aluminum as their metal.

Aurora had a good magnetic field, ranging from .2 to .6 gauss, and that plus its atmosphere was enough to protect the settlers from Tau Ceti's UV radiation. So the surface was well protected in that regard, and really the moon's surface was quite a benign environment for humans, except for the wind. Every day explorers came in from their trips exclaiming at the force of the gusts, and one of them, Khenbish, came in with a broken arm after a fall.

"People are beginning to hate this wind," Euan remarked to Freya during one of their personal calls. "It's not horrible or anything, but it is tedious."

"Are people scared of it?" Freya asked him. "Because it looks scary."

"Scared of Aurora? Oh hell no. Hell no. I mean, it's kicking our butts a little, but no one comes back in scared."

"No one going to go crazy and come back up here and beat people up?"

"No!" Euan laughed. "No one is going to want to go back up there. It's too interesting. You all need to get down here!"

"We want to! I want to!"

"Well, the new quarters are almost ready. You're going to love it. The wind is just part of it. I like it, myself."

But for many of the others it was the hard part; that was becoming clear.

A slow sunrise brought dawn on Aurora, and just over four of their clock days later, the high noon of their month came. During this time the lit crescent of E had shrunk to a brilliant sliver, up there in the royal blue daytime sky, and the blazing disk of Tau Ceti had been closing on that lit side of E as it rose. A time came when the star was too close to E for them to be able to look at either one without strong filters to protect their eyes.

Then, because Aurora orbited E almost in the plane of Tau Ceti's ecliptic, and E too orbited very close to that plane; and Greenland lay just north of the Aurora's equator; and E was so much bigger than Aurora, and the two so relatively close together, there came the time for their monthly midday full eclipse. Their first one was arriving. 170.055, A0.15.

The sun stood almost directly overhead, the lit crescent of Planet E right next to it. Most of the settlers were outside to watch this. Standing on small dark shadows of themselves, they set the filters in their face masks on high and looked up. Some of them lay on their backs on the ground to see without craning their necks the whole time.

The side of E about to cut into the disk of Tau Ceti went dark at last, just as the blazing disk of Tau Ceti touched its edge. E was still quite visible next to it, looking about twice as large as Tau Ceti: it blocked a large circle of stars. The very slow movement of the sun made it obvious the eclipse would last for many hours.

Slowly E's mottled dark gray circle seemed to cut into the smaller circle of Tau Ceti, which was very bright no matter which filter was used; through most of them it appeared a glowing orange or yellow ball, marred by a dozen or so sunspots. Slowly, slowly, the disk of the sun was covered by the larger dark arc of E. It took over two hours for the eclipse to become complete. In that time the watchers sat or lay there, talking. They reminded each other that back on Earth, Sol and Luna appeared to be the same size in the sky, an unlikely coincidence that meant that in some Terran eclipses, the outer corona of Sol appeared outside the eclipsing circle of Luna, ringing the dark disk with an annular blaze. In other eclipses, either more typical or not, they couldn't recall, Luna would block Sol entirely, but only for a short while, the two being the same size, and the sun moving eighteen times faster in the Terran sky than Tau Ceti did in theirs.

Here, on Aurora, during this first eclipse of Tau Ceti ever to be observed, the movement was slower, bigger; possibly therefore more massive in impact, more sublime. They thought this had to be true. As the dark circle of E slowly covered most of Tau Ceti, everything got darker, even the disk of E itself, as what illumination it had was coming from Aurora, which was itself growing darker in E's growing shadow. The light from Tau Ceti that was bouncing off Aurora and hitting E and bouncing off E and coming back to Aurora, was lessening to nearly nothing. They marveled at the idea of this double bounce that some photons were making.

Over the next hour, the landscape completed its shift from the intense light of midday to a darkness much darker than their usual night. Stars appeared in the black sky, fewer than when seen from the ship during its voyage, but quite visible, and bigger it seemed than when seen from space. In this spangled starscape the big circle of E appeared darker than ever, like charcoal against obsidian. Then the last sliver of Tau Ceti disappeared with a final diamond wink, and they stood or lay in a completely black world, a land lit by starlight, the starry sky containing a big black circle overhead.

Off on the horizons to all sides of them, they could see an indigo band, curiously infused with a golden shimmer. This was the part of Aurora's atmosphere still lit by the sun, visible off in the distance well beyond their horizon.

The wind still rushed over them. The blurred stars twinkled in the gusts. Over their eastern horizon the Milky Way stood like a tower of dim light, braided with its distinct ribbons of blackness. The wind slowly lessened, and then the air went still. Whether this was an effect of the eclipse or not, no one could say. They talked it over in quiet voices. Some thought it made sense, thermodynamically. Others guessed it was a coincidence.

About thirteen hours were going to pass in this deep, still black. Some people went back inside to get out of the chill, to eat a meal, to get some work done. Most of them came out again from time to time to have a look around, feel the absence of wind. Finally, when the time for the reappearance of Tau Ceti came, most roused themselves, as it happened to be in the middle of their clock night, and went back outside to watch.

There to the east, the sky now glowed. Though it was still dark where they were, indigo filled much of the eastern sky. Then the infusion of gold in the indigo strengthened in intensity, and the whole eastern sky turned a dark bronze, then a dark green; then it brightened, until the blackish green was shot with gold, and brightened again until it was a gold infused with greenish black, or rather a mix or mesh of gold and black, shimmering like cloth of gold seen by twilight, perhaps. An uncanny sight, clearly, as many of them cried out at it.

Then the burren off on the eastern horizon lit up as if set on fire, and their cries grew louder than ever. It looked as if the great plateau were burning. This strange fiery dawn swept in vertically, like a gold curtain of light approaching them from the east. Overhead the charcoal circle of E winked on its westernmost point, a brilliant wink of fire that quickly spilled up and down the outer curve of the black circle. And so Tau Ceti reemerged, again very slowly, taking a bit over two hours. As it emerged the day around them seemed to dawn with a strange dim shade, as if clouded, though there were no clouds. Gradually the sky turned the usual royal blue of Aurora's day; everything brightened, as if invisible clouds were now dispersing; and finally they were back in the brilliant light of the ordinary midday, with only the sky off to the west containing a remaining dark shape in the air, a shaded area, again as if invisible clouds were casting a shadow over there, a shadow that in fact was that of Planet E, which moved farther west and finally disappeared.

Then it was just midday again, and it would be for four more days, with E waxing overhead, dark gray again rather than black, the mottling of its own cloudscapes clearly visible, the crescent on its west side slowly fattening.

Up in the ship, Freya and Badim, watching mostly Euan's helmet-camera feed on their screen throughout this event, banging around their apartment doing other things but returning time after time to the kitchen to look at it, stared at each other in their kitchen.

"I want to get down there!" Freya said again.

"Me too," Badim said. "Ah, God-how I wish Devi had lived to see that. And not just from here, but from down there with Euan. She would really have enjoyed that."

Then the wind came back, hard from the east. But now they knew that there might come a few hours of windlessness during eclipses. And there would surely be other such hours; on this world of constantly shifting light, the winds too would surely have to shift. They might be almost always strong, but as they changed from onshore to offshore, being so near the coast, there would surely be periods that would be still, or at least swirling. They were still learning how that worked, and no doubt would be for a long time to come; the patterns were not yet predictable. That was aerodynamics, Euan remarked: the air moving around a planet was always in flux, supersensitive, well beyond any modeling they were capable of.

So: wind. It was back, it would seldom go away. It would be a hard thing to deal with. It was the hard part of life on Aurora.

The good part, the glorious part, they all agreed, was the look of the land under the double light of Tau Ceti and E, especially early in the long mornings, and now, they were finding again, in the slanting light of the long afternoons. Possibly the experience of the eclipse had sprung something in their ability to see. In the ship they saw only the near and the far; this middle distance on Aurora, what some called planetary distance, others simply the landscape, at first had been hard for them to focus on, or even to look for, or to comprehend when they did see it. Now that they were properly ranging it, and grasping the spaciousness of it, it was intoxicating. It was enough to make them happy just to go outside and walk around, and look at the land. The wind was nothing compared to that.

One day an exploring party came back from the north, excited. Seventeen kilometers to the north of their landing site, there was an anomaly in the generally straight and cliffed coast, a small semicircular valley that opened onto the sea. This was a feature that had been visible from the ship, of course, and people still on the ship had reminded the surface party about it, and now this group had hiked up to visit it, and having seen it, had come back to base exclaiming its virtues.

It was either an old impact crater or an extinct volcanic feature, but in any case, a semicircular depression in the burren, with the straight side of the semicircle a beach fronting the sea. The explorers called it Half Moon Valley and said its beach was composed of sand and shingle, backed by a lagoon. In the low land behind the lagoon an estuary cut through the valley, then rose through a break in the low cliff of the burren, first as a braided, gravel-bedded river, then as a set of swift tumbling rapids. And the entire valley, they said, was floored with soil. From space this soil appeared to be loess. The explorers' closer inspection had indicated it was a combination of loess, sea sand, and river silt. Calling it soil was perhaps inaccurate, as it was entirely inorganic, but at the very least it was a soil matrix. It could quickly be turned into soil.

This was such promising news that the settlers quickly decided that they should move there. They freely admitted that one powerful attraction was the possibility of getting out of the wind. But there were other advantages as well: access to the ocean, a good supply of fresh water, potential agricultural land. The prospect was so enticing that some of them even wondered why they hadn't landed there in the first place, but of course they were reminded by people in the ship (who had been reminded by the ship) that the robotic landers had had to give the valley a wide berth, to be sure they came down on flat rock.

Now they were safely down, and in exploration mode, and their settlement was still quite mobile, being almost entirely composed of landers; they had built their wind wall but not yet started on buildings. So they could make the move fairly easily.

Over the next few days, therefore, everyone in the station walked up to see the sea valley, and agreed the moment they did that the move should be made. This kind of unanimity was said to have happened so infrequently on the ship (in fact it had never happened) that the people still on the ship were happy to accede to the plan on the ground.

"As if we could stop them," Freya remarked to Badim.

Badim nodded. "Aram says they are acting ominously autonomously. But it's okay. We'll all be down there soon. And it looks like a good place."

At this point, people from the ship were being ferried down to the moon in modules that then served as their living quarters. Nothing was going as quickly as many on the ship would have liked, but everyone had to agree that nothing more could be done to speed the process. They only had so many ferries, and then some had to be refueled and launched back up to ship. Now that they were going to move the settlement to Half Moon Valley, all the work to expand their living space would be delayed. But a brief delay was felt to be well worth it, given the many advantages that would follow the move.

So the settlers got to work moving, a task that seemed easy until they began to do it, when the little declivities and breaks in the burren turned out to be more obstructive to moving their living modules than had been foreseen. The shallow little grabens were easy to walk down small ravines into and out of, and so they had hiked to the valley and back without impediment, but moving their modules on wheeled frames, and their construction robot vehicles, and even their rovers, across them was not so easy. And the grabens were all so long, and trending east-west, that they often could not be flanked.

A best route was found that crossed as few of these troughs as possible, using the algorithm that solves the traveling salesman problem, notorious to all those worried about errors endemic to certain greedy algorithms. But even after extensive cross-checking, the minimum number of graben crossings turned out to be eleven. Each trough had to be bridged, and this was not easy, given the dearth of bridge materials and the weight of the loads on the wheeled carts.

So it was a slow and ponderous trek, and soon after they began, sunset came again. They did not let this stop them, having decided they could make their trip by the light of E. It hung up there in its usual spot, half illuminated-what on Earth they called a quarter moon, an unusually logical name, it must be said. Just after sunset was as dark as the nights got, as E waxed to full and then waned to the other quarter moon before sunrise. The light cast by quarter E was around 25 lux, which was 25 times the illumination of the full moon on Earth; and though it was four thousand times less than direct sunlight on Earth, and six thousand times less than full taulight on Aurora, it was still about the same illumination as a nicely lit room at night in the ship, which was certainly enough to see by. So they worked in this light, and formed a long caravan of their vehicles, and headed north over the burren. In the end they declared the E light quite beautiful, easy on the eyes, things slightly drained of color but extremely distinct.

Euan and the rest of the bridge-building team went into action when they came to the edge of the first trough. One of them drove a stone-cutting vehicle to the edge of the trough, well away from where they intended to cross, and put to work a rock saw attachment at the end of the vehicle's backhoe. Cubes of rock were cut from the side of the graben, then lifted and conveyed hanging from the backhoe to a steep-walled section of graben, where the opposite side was both close and as vertical as could be found. The first cube was hard to get loose, but with some knocking with the side of the backhoe they managed it. Cubes three meters on a side were as large as the vehicle could safely lift. When they got them to the edge of the graben they lowered them into the trough, all very slowly, especially if the wind was gustier than usual. Every four or five cubes, they had to stop and swap out the saw blades they were using, both the circular blades and the thin up-and-down saws that Euan called dental floss. Their printer refurbished worn blades with new synthetic diamond edges, and they attached these and continued cutting cubes and depositing them in the trough to make a rough ramp. When the ramp extended far enough into the trough that the vehicle arm couldn't reach out far enough to place new cubes, they filled the gaps between cubes with gravel that other teams had crushed, then unrolled by hand an aluminum mesh carpet to provide a bridge surface smooth enough to drive onto. Euan then drove the cutter vehicle out onto this ramp, another cube dangling heavily from its front end, everything looking precarious, especially when swaying in hard gusts of wind, until he reached the leading edge of the new ramp and could lower the next cube of rock into place.

They were nearly done with this first ramp when Eliza dropped a new cube into place without realizing the trough bottom was not smooth. This was perhaps a result of them working in E light, but in any case, the new cube tilted into another cube already in place in a way that meant their vehicle could neither lift it nor move it, without dangerously tipping the vehicle.

Euan took over the controls from Eliza to give it a try, but he couldn't move it either, though he rocked the vehicle dangerously to the side. So it lay there blocking their way, making the ramp impassable, and tilted as it was, it looked like they would have to abandon the entire ramp and start over.

"Let me try something," Euan said, and used the rock saw to cut a trapezoidal segment off the top of the tilted cube, then carefully wedged the segment into the gap left under the tilted cube. After attaching the pile-driver tip and doing some hard tamping with the crane, they concluded the combination was going to be stable enough to drive over, and so they continued cutting cubes and placing them in the trough, more carefully than ever, often with Euan given the controls to make the final drops.

"He's an artist," Badim said to Freya as they watched from the ship.

"That's why he's down there and I'm not," Freya said. "They don't need Good For Anythings down there."

"They do," Badim said. "They will. It was a lottery, remember."

After three days of work, the ramp across the trough was finished. They sent across a robot truck first to test it, and it ground over the aluminum carpet without incident. All was well, and they drove or directed all the other vehicles over the ramp. There were thirty-seven vehicles in their caravan, ranging in size from four-person rovers to mobile containers that were the modular parts of their buildings. All crossed without incident. But that was only the first of eleven grabens.

However, they now had their method, and because of that, the subsequent ramps went a little faster. Even the so-called Great Trench, a graben three times wider and twice as deep as the rest, was ramped and crossed in a day. Stopping to swap out the rock-cutting blades became the biggest delay. In this task, both the versatility and the unreliability of humans doing mechanical work was revealed. The operator would set the vehicle arm on the ground with the nut holding the blade to the rotor facing up, and someone would fit the power wrench to the nut and zip it off with a pneumatic blast. Off came the nut and washers, after which they spun the circular saw blade carefully off the short spindle, being careful not to damage its screw threads. Then they carried the blade to the machine truck, where printers would have readied a newly sharpened blade. Go back and spin a refurbished blade down onto the spindle, put the washers on, then the nut; last, apply the power drill and tighten the nut. This was the moment where humans were not as good as a robot would have been, and their tools not adequate to compensate for their inexperience. The problem was they could not tell how tight the nuts were being screwed on by the power drill, and very often, in the attempt to be sure they were tight enough, they drilled them too tight. Threads were stripped, and then there was no grip at all, and the spindle had to be replaced, which took many hours of delicate work; or washers were fused together, or fused into the nut or the blade, such that they could not be separated afterward, even with the power drill at full power.

This kind of mistake happened so often that eventually they allowed only Euan and Eliza to use the power drills for this task, as they were the only ones who had the touch to do it right. Anyone listening to Euan's feed to the ship, including Freya and Badim and a few score others, got used to the heavy airy blat of the power drill working, and they also got used to his various favorite curses as he lamented one action or another.

The settlers rolled slowly across the land, averaging 655 meters a day, with their longest day only three kilometers, and that between two troughs, over flat burren. It took them twenty-three days to move their settlement to the sea cliff overlooking Half Moon Valley, on the shore of the western sea. They had traveled by the light of Planet E as it went through its full phase, a huge sight; they noted the lunar eclipse in the middle of that, the shadow of Aurora diffusely crossing the face of E, dimming it somewhat, but not too much, because E was so much bigger than Aurora, and the two so close together, and both with thick atmospheres, which diffused Tau Ceti's light around Aurora and meant E was not very shaded by it. After that they had scarcely noticed the dimming of E's slow wane, which brought back in the lambent night more blurry stars. These stars slowly shifted overhead, and the phases of E also shifted, but E stayed always fixed in place over them, a bit south and east of the zenith. Some settlers said this felt strange; others shrugged.

Near the end of their trek, they waited out a hard rainstorm, when it got too dark and wet to travel safely. And they stopped work to witness the sunrise of Tau Ceti, painfully bright over the burren to the east. Like a nuclear explosion, some said, in what was perhaps a false or mistaken metaphor, as it was in fact a kind of nuclear explosion.

Though they could see down into their ocean valley, they were still on the cliff above it, and so had to bulldoze a ramp road down the side of the river canyon that formed the largest break in the sea cliff. This tilted curving road was the work of another eight days. When it was finished, they drove all the vehicles down to the valley floor and located them near the bottom of the cliff, on an alluvial floodplain near the river. This was clearly going to be the spot in the valley best protected by the cliff from the winds. At least the offshore winds.

As they quickly found, there were times when the winds poured up and down the river canyon even faster than they had out on the burren, as the gusts were channelized by the canyon. Once this became clear they moved their caravan farther from the river, and got some protection at the foot of the cliffs about two kilometers from the canyon mouth. This was a relief to all. Their new location seemed the best they were going to be able to find in this region of Greenland, all things considered. So they began to settle in at the foot of the curving cliff, and later in some steep, short gulleys that ran up the cliff to the burren. These ravines were transverse to the prevailing winds, and therefore well protected, but mostly steep-walled, with narrow floors.

To aid the wind break of the cliff, they began to build what they called city walls out from it. One would encircle their residential complex, and another one, longer still, would enclose the first fields they hoped to plant in the open air.

Every day there was more to be done than they could do, and they welcomed the regular infusion of people who started coming down again from the ship. They jammed these newcomers into the shelters as tightly as they could manage. Everyone ate food sent down from the ship. They kept the printers on both Aurora and the ship working continuously, making all the parts they required to assemble their new world. In this process their feedstocks and simply time itself were the only limiting factors. They couldn't make more time, but they could send mining expeditions out onto the burren to locate metal ores and replenish their feedstocks, and they did.

More people descended, bringing them to just over one hundred total. Greenhouses now became crucial. They hoped eventually to grow crops out in the open air, and the chemical composition of the air was adequate for this, indeed nearly Terran; but during the nine-day nights, despite the waxing and waning light of E overhead, the temperature dropped to well below freezing. It wasn't obvious how they were going to solve that, in regard to their agriculture. There were winter-tolerant plants that cold-hardened and went dormant, and survived freezes; the farm labs on both ship and Aurora were investigating how these plants accomplished that, and whether the genes for that ability could be transported to other plants. Also they were looking into genes that could help plants adapt to the daymonth cycle rather than annual seasons, but the outcome of this effort was not clear. For now, whatever they ended up planting, greenhouses were necessary.

At first most of the greenhouse space was given over to growing soil itself. Soil as opposed to dirt was about 20 percent alive by weight, and plants were very much happier growing in it than they were in dirt like the valley's dead loess. When they had viable soil, which fortunately grew in tanks filled with loess at nearly the speed of bacterial reproduction itself, they spread it in the greenhouses and planted crops. These were mostly fast bamboos at first, bamboos they had nursed throughout the long voyage to Tau Ceti without much needing them; now they came into their own, as they were a crucial building material, providing strong beams at a growth rate of a meter a day. Meanwhile the settlers' food still came mostly from the ship and was flown down to them.

This created another supply problem. They had robot ferries capable of flying down from the ship to Aurora, then refueling and launching to get back up to the ship, but they needed fuel. One of the factories in the valley was entirely devoted to splitting water into oxygen and hydrogen, the main components of their rockets' fuel. The factory itself had to be powered, however, and splitting water was very energy-intensive. They had two powerful nuclear reactors with them on the surface, providing 400 megawatts total, but the uranium and plutonium in the reactors would not last forever, and the ship's supply was only adequate for the ship. Was there uranium on Aurora? According to standard theories of planetary formation, there had to be some; but the entire Tau Ceti system was less metallic than the solar system, and heavy metals only accumulated well on planetary bodies with a steady churn of tectonic action or tidal flexing. It wasn't clear Aurora had ever had either, and given the uncertainty on this point, it was felt that they were going to have to devote a good deal of their manufacturing capability to building wind power generators on the burren. For sure there was going to be enough wind.