Xeelee Redemption

by Baxter, Stephen

  Susan nodded. ‘I will accompany you. I rarely venture into the Valleys these days – usually only when some catastrophe has struck my crew. This time I will make an exception, for the chance to talk. The Ghosts may eavesdrop, but there will be opportunities.’

  Nicola touched her shoulder. ‘You’re a remarkable person, Susan Chen. Come on. Let’s get this done.’

  17

  The three of them were to be flown down from Ghost Plateau into a feature about eight hundred kilometres to the planet’s east, which Susan, who among other things had done her best to compile a global map of Goober c, called ‘Xeelee Valley Number Five’.

  The four of them climbed into, as Jophiel immediately recognised, what had evidently once been the hull of a standard Poole Industries flitter, originally carried by the scattership Gourd. The propulsion units had long ago been cut away, leaving a human-life-support shell that was now embedded in a tangle of Ghost rope. The hull itself was much aged, and in its interior every surface was rubbed to smoothness, the worn-out soft parts of the couches replaced by hand-stitched cushions and blankets. It was strange to Jophiel to inspect what was for him contemporary technology so obviously aged: the craft’s control instruments, detached or inert; softscreens probably blank for a millennium.

  When the craft lifted from the ground, evidently held firm in the Ghosts’ inertia-control field, there was barely a sense of motion. But the view out of the windows was astounding.

  Harris Kemp goggled, his forehead pressed to the window beside his seat. ‘Take a look back at that plateau. Makes Tharsis on Mars look like a mud pie. And those valleys . . .’

  Susan seemed oddly pleased, Jophiel thought. As if she was proud of her prison-planet.

  Xeelee Valley Number Five turned out to be a vast rift valley, deep and long, its walls sheer, one of several tremendous cracks in the crust that led off from the gigantic bulge of the plateau. It seemed clear to Jophiel that this feature had nothing to do with erosion by running water, like Earth’s Grand Canyon; it was nothing less than a crack in the crust of the planet.

  The craft dropped into the valley, passing along one of the great walls. The light was poor, the clouds thick in this world’s dense layer of atmosphere, but still they were close enough to the wall to make out detail. Jophiel was no geologist, but he recognised the signs of past catastrophes in the complex strata. Here a sheet of basalt, a relic of some huge volcanic event, was wearing out of the wall as softer rock eroded. Above that was a layer of tumbled rocks, huge and angular, as if dumped by a tremendous tsunami. Above that beds of what looked like sandstone, deposited by some vanished ocean.

  And, here and there, clinging to the strata or dangling in blankets over the cliff face, a pale, almost apologetic green.

  ‘Life,’ Nicola said, staring out.

  Harris groaned. ‘I wish I had better instruments than my own eyes to observe all this.’

  ‘Maybe next trip,’ Jophiel murmured. ‘If we can get the Ghosts to trust us a little more . . . Is it life, though, Susan?’

  ‘Indeed it is. And native to Goober c, as far as we were able to tell, back in the days when we had the means to study it, when some of the original crew survived. Alongside the first generations who we managed to train up, to some extent.’

  ‘Anaerobic, though,’ Harris said. ‘The life here. Every scrap of it we’ve seen so far. That is, it doesn’t exploit oxygen.’

  ‘Correct,’ Susan said. ‘That’s what we worked out. You understand the thick air of this world is choked with carbon dioxide – that alone would contribute about five times as much pressure as all of Earth’s atmosphere. A product of all the volcanism, no doubt. It traps a lot of heat, making the planet warmer than it has any right to be so far from the star.

  ‘And the carbon dioxide in the air is what the life here feeds off. There’s some kind of metabolic chain that exploits sunlight to cause carbon dioxide to react with other gases and minerals to liberate hydrogen – and it’s the recombination of hydrogen that seems to power the larger and more complex plant growths. And animal life. Hydrogen plays the role that oxygen does on our worlds. Well – again, we thought so. We were never able to survey properly. This world is so large, you see, that its continents have remained largely islands, cut off from each other, and entirely different evolutionary strategies seem to have been tried out. As if there were several planets compressed into one. The Ghosts keep the fauna away. We never got a close look. But anyhow it will soon make no difference.’

  The Island crew listened to this, electrified.

  Jophiel said, ‘You’re talking about the upcoming nova event.’

  ‘Indeed.’

  Harris nodded. ‘I’ve done more work on that with Asher. That star is becoming more unstable every time we look at it. It will climax in a violent event soon – maybe only months away – it will be something like a nova, yes. And this world will be battered.’

  Nicola grunted. ‘Just our luck.’

  Chen shook her head. ‘Actually, perhaps not. We have been held by the Ghosts for a thousand years, but we soon suspected the Ghosts have been here longer still. A long time. You can see the evidence on the airless worlds better. The moons of Goober c itself, for instance. Structures, visible through the telescopes we had then.

  ‘But now, you see, we are here, a species the Ghosts are unfamiliar with and cannot, I think, understand. Because, from the Ghosts’ point of view, we suddenly exploded out of a system which the Xeelee had visited. And you have the anomaly of the Wormhole Ghost, with its bad news for its own kind . . . Perhaps the Ghosts have accelerated their project as a result.’

  Jophiel tried to think that through. ‘Susan. What project? Are you suggesting that the Ghosts have got something to do with the nova event?’

  But before she could reply the flitter dipped, banked, lurched.

  Jophiel glanced out of his window at the fleeing ground. On the floor of the great valley a river meandered – itself a mighty torrent, but obviously not the creator of this huge geological wound. And there, just ahead, a kind of pale, milky glow. A colour Jophiel recognised, after his experiences in the Solar System, even in this cloud-choked world’s murky light.

  ‘That’s Xeelee hull plate,’ Nicola said.

  ‘Indeed,’ Susan said softly.

  They fell silent. The flitter ducked and swooped, beyond any human control. And soon pale artifice, complex and crusted and covering the ground, swept under the prow. As the flitter descended, Jophiel made out what might have been a cityscape, a scatter of blocks, of pyramids and cubes, pillars and towers – but there was a randomness to it all that made the plain look as if it was covered by huge salt crystals, perhaps, eroding from some seam.

  Still the flitter dropped, until it touched gently down.

  Unreal as he was, Jophiel climbed cautiously down the flitter’s steps to the planet’s surface.

  Hard, warm rock underfoot. The air was warm too, thick, murky, thicker than any fog, and it resisted his motions as he tried to push through it. It was like wading across an ocean floor.

  Susan Chen stood patiently as Jophiel, Nicola, and Harris Kemp laden with his Virtual-generating backpack, took slow, exploratory steps. She said, ‘Some people feel claustrophobic in this air. As if they’re drowning.’

  ‘I wish you hadn’t said that,’ Harris said.

  Nicola pointed to shadows, what looked like a cluster of buildings in the murk. ‘I take it that’s our target.’

  ‘Indeed.’ Susan took cautious steps in that direction, leaning on her stick.

  Jophiel and Nicola walked side by side. Harris followed Susan, walking as slowly as she did. He muttered observations into a voice recorder, one of the few technological gadgets the Ghosts had allowed on this trip, aside from the skinsuits and Jophiel’s projector box riding on Harris’s back.

  ‘We have plenty of time,’ Susan said. �
�It is near local noon; the day-length of this planet is only a little more than Earth’s. It is best if we stay together, however. The Ghosts find it less alarming if we don’t scatter. Come along . . . I wouldn’t bother making a map, by the way. Or if you do, don’t take it too seriously.’

  Jophiel wondered what she meant by that.

  They were already nearing the buildings, Jophiel saw. Blocky geometric shapes, mostly cuboid, some spheres, pyramids – even a spindly tetrahedron. None much taller than a couple of storeys, in human terms. Looming out of the turbid air.

  ‘We will find my crewmates soon. They never go far. Follow me. Keep your eyes open – especially look for technology, portable artefacts. That’s what the Ghosts want.’

  Nicola snorted. ‘Now you sound like my mother. She would always set me a test every time we went for a walk.’

  Jophiel thought he heard Susan sigh; it was such a soft sound he wasn’t sure. ‘I suppose I have been a mother, for a thousand years. One gets into habits of speech.’

  They came to the buildings.

  They followed a narrow street, between the blank faces of two relatively small structures, each maybe three metres tall. No, not blank – Jophiel saw their walls were marked with pale pink crosses, roughly daubed. Jophiel could see no doorway, no windows, no sign of what these box-like buildings might have been erected for. Only these empty, pale walls. And when he looked down at his feet he saw he was still walking on basaltic ground. There was no road surface; it was as if the buildings had been set down on the bare rock like a giant’s toys. Toys made of Xeelee hull plate.

  They came out of the alley at an intersection. More buildings all around them, set not quite in regular rows, so that the roads and alleys between them were offset and followed odd angles – some widened, some narrowed. A little further ahead, Jophiel saw, was a group of much taller buildings, still essentially box-like, cuboids and pyramids and spheres. The central cluster cast long shadows over the other buildings. It looked like a downtown in a city of the American Anthropocene, he thought, like New York, perhaps.

  ‘No markings,’ Nicola said.

  ‘What?’

  ‘Wake up, Poole. Markings? None on this building. See?’ She pointed to a small, slim monolith between two, towering pyramids. ‘But look what Susan is doing.’ She pointed again.

  Susan had stopped by another small building, between two giants. ‘This is the one we just cleared, I think . . .’ She took off her pack, drew out what looked like an ancient can of paint, slipped her gloved hand into the pot, and crudely scrawled a cross on that virginal surface. Then she moved on.

  Harris went over to inspect. He touched the pale, sticky liquid. ‘Interesting stuff. Paint that sticks to Xeelee hull material.’

  ‘Paint! That’s hardly the priority,’ Nicola said testily. ‘Why is she doing this? How long has this been going on?’ She looked around with a fresh eye. ‘What is this place? What’s it for? How does it work? Hmm . . .’

  ‘You’ll see. This way.’ Susan Chen smiled and beckoned, pack on her back, leaning on her stick, the paint pot in her free, gloved hand.

  She led them down another skewed alley.

  And brought them to a door, in the wall of the building she had marked.

  It was just another box, distinguished only by the fact that it had a doorway – a rectangular space, open, with no cover.

  Inside there were no fittings that Jophiel could see – nothing save for a pair of low pillars, one at either end of the single big room, that looked as if they had grown out of the floor. The pillars appeared to be made of Xeelee hull plate, like the rest of the room.

  The interior looked like it spanned half the width of the building. There was evidently a partition, with a further door. Jophiel thought he could hear faint voices, coming through the door.

  The space glowed with a soft internal light. The four of them, staring at this geometric perfection, looked grubby, clumsy, unfinished.

  Susan smiled at them. ‘Don’t worry about dusty footmarks. The place seems to self-clean. They all do.’

  Harris walked over to one pillar; it was about waist-height. ‘Why are we here? I mean, why do the Ghosts send you here?’

  Susan waved a hand. ‘You understand this is a Xeelee station, of some kind. All of this is Xeelee construction material – as the Ghosts call it. I understand you call it hull plate, or membrane, depending on the grade. A replicating material that grows in sunlight. There are no Xeelee here. All this is automated somehow. And what we’re looking for is Xeelee artefacts.’

  ‘Artefacts?’

  ‘The whole of this “city” is a Xeelee artefact, of course. We seek small, portable devices. I’ve only ever seen two kinds. Two, in a thousand years.’ She patted one pillar. ‘One type is associated with pillars like this. You always find them in such rooms, sitting on pillars, facing each other. Hoops, each maybe half a metre across. Sky blue, polished – paper thin – and before they’re detached from the pillars you can see pink sparks dashing around the circumference. They go inert when removed, as they have been from this place, as you can see. The Ghosts think they are some kind of comms device.

  ‘My own best guess is that this particular kind of installation is a monitoring station.’ She cast a shy glance at Jophiel. ‘I did follow your adventures when I was young,’ she said. ‘When you chased the Xeelee into the heart of the Sun. You thought it was studying creatures of dark matter there . . . Maybe that’s what this station is for. An observation post for the Xeelee, to monitor an anomalous star. With some kind of comms system, the hoops perhaps. Well. If the Ghosts ever made this work, or figured out its principles, they haven’t told me about it.’

  Jophiel thought it over. ‘So the Ghosts came to this system, you think, knowing this Xeelee station was in place. But abandoned. Or left uninhabited, anyhow.’

  ‘The Ghosts want the stuff,’ Nicola said. ‘Xeelee treasure. Like Saxons in Britain, looting a deserted Roman town. But now they have been disturbed. They’ve detected Xeelee activity relatively nearby – I mean, in our Solar System. As soon as there’s a hint that the legions are returning, the Saxons are looking over their shoulder . . .’

  Susan smiled at the analogy. ‘It is a very long time since I thought about Saxons and Romans. We must talk.’

  ‘I’d like that.’

  ‘And the other kind of artefact?’ Harris asked.

  ‘A flower, we call it. A Xeelee flower. A core from which hull plate will grow. You’ll recognise it when you see it.’

  ‘Ah,’ Jophiel said now. ‘We hypothesised the existence of such things. We never found one, back in the Solar System. We called them “seeds”.’

  Susan gently tapped one wall with a flat, gloved hand. ‘Growth is the key. So I have learned, in time. Though meaningful observation takes decades. Like watching a forest grow – yes, exactly like that. Can you guess how this place works yet? It’s not like a town, a human-built environment. However, it fulfils whatever function it has – it’s more like a community of living things.’

  Jophiel for once was at least one step behind. He was still distracted by those apparent voices from beyond the doorway, muffled in the heavy, almost liquid air. ‘Living?’

  Susan smiled again. Jophiel had the strong impression that she was enjoying this, enjoying having an audience, as well she might. ‘You’ll have to take my word for it. Over time – by which I mean years, decades – these buildings change. They grow. And sometimes they move; they will detach from the surface, and—’

  Harris broke in, excited, ‘I think I know what she means. This building grows, literally. It is nothing but hull plate. So maybe it starts from a seed of hull plate – Susan’s “flower” – and grows, converting starlight energy to mass, to this planar material – and the more it grows, the more light it soaks up, and it grows some more. It’s an exponential process, we have good mathema
tical models. Just as we saw with the Cache in the Solar System, so with this building. It must be growing into some pre-programmed form, presumably, reaching some maximum size—’

  ‘Or it would, if not for the presence of other buildings around it,’ Susan said. ‘Which, you see, block its light, and therefore its growth.’

  And Jophiel thought of the long shadows cast by the ‘downtown’ he had seen. ‘It’s like a forest, then,’ he said. ‘These buildings aren’t planned. They just grow where they can, competing for ground space and light – yes, just like a forest, which is dominated by big tall trees, and smaller growths stunted in the shade.’

  ‘Even the timing is persuasive,’ Harris mused. ‘At the orbit of Earth, the doubling time of Xeelee hull plate was ten or fifteen years. The sunlight is less here, but . . . A building would grow at the rate of a tree. Over decades.’

  ‘Well done,’ Susan said, nodding. ‘You got it quickly. But, as I said, this forest of buildings changes. Sometimes day to day. Not just the size of the buildings, but their locations. They aren’t rooted to the ground, you see. That’s why we got into the habit of marking the buildings – the Ghosts supplied us with a kind of adhesive paint, so we can label those we have searched. We don’t know the full life cycle, and if the Ghosts know they don’t tell us. Perhaps older buildings collapse, or drift off into space—’

  ‘Or are consumed by their competitors,’ Nicola said with a certain relish. ‘Like strangler figs. All this is plausible, isn’t it? A hull-plate ecology. One thing we learned about the Xeelee back in the Solar System is that everything about the Xeelee is like a merger of life and technology . . .’

  Again, those voices. Softly bickering, it sounded like. Jophiel asked, ‘Susan. Who else is in here?’

  ‘My crewmates, of course.’ She looked oddly embarrassed, though the expression on her ancient, immobile face was hard to read. ‘If you are ready – you should be prepared.’

  Nicola took her gloved hand. ‘Just show us.’