Xeelee Redemption

by Baxter, Stephen

  He nodded to Asher, who stood up now.

  ‘However, we don’t have to stay on this deck,’ she said. ‘We have somewhere else to go.’

  ‘You’re talking about the cupworlds,’ Chinelo called up.

  ‘You all saw them during the flyby of Deck Three. Environments the size of worlds, indeed – and we found at least two, we think, Earthlike enough for us to survive with a minimum of tech support. Though don’t hold me to that before we get up there and figure it out.

  ‘And, listen. The cupworlds may help us solve our other problem. If we climb back out of this relativity pit, we’ll gain more time. Five million years out in the universe is just a year down here. But that Deck One year stretches out to ten thousand years on Deck Two, and a million years on Deck Three. You see? We can win living space, and living time, too. And better yet, we’ll leave the Xeelee down here, in its time pit. Until we’re ready to deal with it.’

  Chinelo frowned. ‘But when we get to a cupworld, what if there’s somebody already there?’

  Max Ward grinned, and bunched a fist. ‘We negotiate.’

  ‘I have a question, though,’ Nicola said now. ‘The cupworlds – how do we get there?’

  Michael held up his hand. ‘We have a solution. Trust me on that. We’re working on the details. But we do have one more big problem. Which is—’

  ‘I know that one,’ Max Ward said. ‘The Xeelee. Which is what we came all this way for. Where is it, and how do we get to it?’

  Poole smiled. ‘Good news – we spotted it. We think. One of Asher’s surveys of Deck One. There were some signatures that don’t appear to be replicated elsewhere on the Wheel, as far as we can see. Gravity waves, for instance.’

  Nicola grunted. ‘And the bad news?’

  ‘It’s light years away. On this deck, but off around the space-contracted curve of the Wheel. We came down at random, remember. It could have been worse, but we lucked out.’

  Nicola said, ‘Tell me you have a way of getting to it . . . Oh. You’re working on that too, right? Which is why we need to buy more time. And a place to live. And if that’s going to be a cupworld— OK, Poole. What’s your brilliant plan to get there?’

  Poole kept smiling. ‘We build trucks.’

  In the end, it was estimated, it would take four months for – as Nicola put it – the crew of a crashed starship to convert themselves into a children’s crusade. A hundred and twenty days after the landing on Deck One. A third of their star-life year.

  So they got to work.

  FIVE

  Think of the story of the race. Our timelines emerged from the oceans, and for millions of years circled the Sun with Earth. Then, in a brief, spectacular explosion of causality, the timelines erupted in wild scribbles, across the universe. Humanity was everywhere. But now, our possibilities have reduced.

  Lieserl, c. ad 5,000,000

  47

  Ship elapsed time since launch: 25 years 256 days

  Earth date: c. ad 1,796,000

  ‘Walk with me,’ Michael Poole snapped.

  Jophiel was happy to obey.

  He rarely got any kind of attention from his template. Nicola and Asher tried to manage the two Pooles’ fractious relationship: Asher with tact, Nicola with barbed jokes. As if they weren’t to be trusted together.

  Yet here they were, in their reinforced skinsuits – one authentic, one a consistency-protocol sham – just one day, three watches, away from departure time. A milestone that Max Ward, who Poole had appointed a particularly ferocious keeper of the schedule for this phase of the mission, insisted was not going to be missed by anybody. Walking out together, away from the Cauchy lifedome, and towards the trucks of the convoy, around which even now there was much frantic activity.

  ‘Second pair of eyes,’ Poole muttered, as they approached the first truck, the rearmost of the convoy. ‘You know how it is. You remember how it is. On every big project, every big milestone, every irrevocable step—’

  ‘I know. You make sure you haven’t missed anything. Nicola has stories of the military flyers of the Anthropocene. They were pilots, not engineers. But they’d do the same for their planes. They’d walk around the birds – they’d kick the tyres, Nicola says. Just checking what they could see.’

  Poole seemed uninterested in the anecdote. But then he might know it already. Jophiel couldn’t remember if Nicola had recounted it before his split with Michael, or after. A shared past could make small talk tricky.

  Poole was silent, his stony, AS-preserved face expressionless, softly underlit by the reflected glow from the hull-plate floor. Michael Poole was sixty-nine years old now, and yet he seemed ageless – unlike, Jophiel thought, the grey avatar who occasionally visited him, who seemed to be ageing with acceptance and grace.

  When they reached the trucks, they looked back at the lifedome. Already gutted of its essential systems, its smooth hull broken open by gaping gashes, its inner partitions and structures cannibalised, it sat, still almost elegant, almost wistful, on the pale floor of the Wheel deck. Jophiel reflected that he would never have guessed that the thing had crash-landed here. This fragile component had kept a lost crew alive. But now it had had to be sacrificed to support the next phase of the crew’s strange journey.

  The best estimate, given by Asher’s scratch team of astronomers together with Poole and his engineers, was that they faced a journey of a hundred and fifty days – subjective – across the Wheel to reach Earth Two, the Earthlike cupworld up on Deck Two, that was their destination. Not an easy estimate to make, not an easy plan to construct. The Pooles had built wormholes amid the moons of Jupiter. Now they were planning to drive across interplanetary distances. And their cargo could not have been more precious, consisting of, for all they knew, the last humans anywhere, in this future age. The last, including infants and newborn – and, Jophiel thought, that other newborn, the dark-matter larva in its hull-plate pod, stolen from the Ghosts at Goober’s Star, which had been carefully stowed in one of the trucks. If that other Michael Poole was correct, that particular orphan could turn out to be the most significant refugee of all.

  Hence the convoy.

  The core of it were the trucks themselves, hastily improvised. Their hulls had mostly been inner buildings, dismounted from the interior of the lifedome and hauled out here, set in a rough line, and equipped with GUTengines and wheelbases. These structures were already robust and had the rudiments of independent internal life support. Before its launch the Cauchy’s original design as an interstellar exploration craft had been heavily reworked to make it resilient in case of damage, even purposeful attack, so these inner buildings were like storm shelters. The wheels, meanwhile, were treated with so-called Kahra-pad hull-plate adhesive. Everybody hoped this feature wouldn’t be necessary; after all, the simple spin gravity of this astounding artefact kept everything it carried stuck to its inner surface. But the Pooles couldn’t be sure of that. After all, to reach Deck Two they were going to have to climb . . .

  They had no space-capable flitters – all had been mounted in the GUTship’s spine or docked to the base of the lifedome, and had been lost when the dome had been severed from the rest of the ship. They did have one atmospheric-capable craft, a flyer, taken apart and to be carried as components within the convoy until needed. But Jophiel, like Poole, was anguished that they had lost all their spacegoing capability.

  Anyhow the two of them walked around the convoy, checked what they could, softly spoke to people labouring to meet their deadlines – they even lent a hand with loading stuff. Everybody knew it was symbolic, nothing more. Just a day out from departure, all the decisions had been made, all the work that could reasonably be done had been finished.

  They were committed.

  One more sleep.

  Then they began.

  48

  Ship elapsed time since launch: 25 years 257 day
s

  Every step of the way was planned.

  The trucks rumbled slowly forward, at no more than walking pace at first, with skinsuited observers outside watching softscreens with diagnostic data.

  The convoy stopped after an hour with only a few kilometres covered, and the rest of the watch was spent checking over the vehicles, and fixing minor flaws: an unbalanced axle, one GUTengine running slightly out of true, an odd smell in one of the habitable compartments that turned out to be the result of a clogged algae filter.

  The lifedome was still easily visible, a broken bubble on the flat infinite horizon.

  At the restart there was a changeover of crew. Now Poole ordered that the vehicles be run up to their operating speed, of five hundred kilometres an hour. The engineers were confident of the capacity of the GUTengines, heavily screened against quagma phantoms, to handle the job. It was the much more primitive mechanics of the improvised wheels and axles and transmission linkages and gears, all hastily adapted from other uses or manufactured with matter printers, that concerned Poole and his team. So, after half a watch’s running – a mere two thousand kilometres covered – Poole ordered another halt, another half watch of inspections, repairs, replacements.

  On the third watch, at last, Poole allowed a running of a full eight hours at the nominal speed.

  After that the expedition settled into a rhythm, of two watches on, one watch off each day. Soon they were making a respectable eight thousand kilometres a day – about a fifth of the Earth’s circumference every day, Jophiel reminded himself, an epic journey in the context of most of humanity’s history, but a baby’s footstep on the Wheel.

  After a couple of days there was grumbling about that two on, one off pattern, with a whole watch being ‘wasted’ every day. The vehicles ran with impressive efficiency, and there was rarely a repair or maintenance task that could not be accomplished in motion.

  But it wasn’t just the machinery that needed a break from the endless travelling. Soon, even Jophiel found himself counting down to the end of another sixteen-hour stretch in confinement, after which the trucks would be drawn up in a rough circle, and people would pour out of the airlocks in their skinsuits, to walk, run, exercise – even play some sport. The children, predictably, made the most of the breaks, with some of the older ones using their hours of freedom to dash away, as far as they could get towards an illusory horizon. Their parents groused that it was just as well that on this table-top of a surface it was impossible for them to get out of sight.

  Conversely there were some people who seemed reluctant to leave their cosy interior environments, if they got too immersed in some project – a study, a hobby, work, a game, a relationship. Poole put Max Ward in charge of making sure that everybody got out of the vehicles at least once a day.

  Even Susan Chen walked daily. Often she was accompanied by Nicola: two victims of Goober’s Star, Jophiel thought, and they made an odd couple, the small, bent old woman, the awkward silver-plated statue. But Harris Kemp said they were good for each other, that Susan was slowly talking her way out of the profound shock of the final revelation of the Ghosts’ manipulative kindness, their preservation of the illusion of her crewmates’ descendants. ‘Walking and talking,’ Harris said. ‘Best therapy we’ve got, for both of them.’

  So the crew settled into a routine.

  They travelled on, and on.

  And, as Jophiel never forgot, for every day they travelled, nearly fourteen thousand more years shivered by in the universe beyond the Wheel.

  The crew had declared the Wheel’s spinward direction as ‘east’, which in turn determined north, west and south. In those terms the Cauchy had landed a hundred and sixty thousand kilometres south of the centre line of Deck One – about a sixth of the deck’s width away from that axis.

  And so the convoy now headed steadily north, seeking the centre.

  They travelled over a featureless, edgeless plain, but with the mighty slash of Deck Two running across the sky above their heads, and the great relativistic washes of light, blue and red to east and west, at least it was impossible to lose their way, Jophiel thought drily. At this rate of travel, including the one-watch stops, it ought to take the convoy some twenty days to reach the centre axis.

  On the nineteenth day, they reached the river.

  They made an unscheduled stop. Poole left Max Ward in command of the convoy, and led a party forward to investigate: Jophiel, Nicola, Asher, Chinelo.

  Asher and her colleagues had long known of the existence of the centre-line hull-plate ‘river’, in theory. It was part of the grand, networked flow of hull plate around the structure of the Wheel. Their whole strategy for the trip, the whole of their future lives, depended on them being able to understand this latest phenomenon. Understand, and safely exploit.

  But they didn’t even know how wide it was. It hadn’t been clear exactly when they would come to what Jophiel supposed they had to call its ‘bank’.

  So now Poole and his companions confronted utter strangeness. Standing in a line, looking north, facing – nothing.

  ‘I can’t even see it,’ Chinelo complained. She took a tentative step forward. Tapped the surface with her toe, flinched back. Set down her foot, firmly. Pulled it back. ‘Can’t feel anything strange.’

  Asher said, ‘But it’s there. Look, Chinelo, here’s a neutrino scan . . .’

  Chinelo looked into the softscreen, and Jophiel looked over her shoulder. To his right, to the east, the ‘river’ glowed a subtle blue – a blue that intensified the further north he looked. And to the west, a redness, a pink fading to crimson.

  Chinelo had grown up with this kind of symbolism. ‘Blue shift and red shift.’ She stared at the floor. ‘It’s flowing. From east to west. Even though you can’t see a bank.’

  ‘No discontinuity,’ Poole said. ‘Just a smooth transition. And it’s actually a double stream. Two rivers, side by side, each ten thousand kilometres across. One flowing west, like this one, its partner flowing east. Each one is stationary at the bank, and at the interface between the streams. At their centre lines they flow the fastest. We actually know how fast. In their centre lines, you’re looking at six per cent of lightspeed.’

  Chinelo goggled. ‘That fast?’

  ‘It is a big structure,’ Jophiel said gently.

  ‘It doesn’t look like it’s going at six per cent of lightspeed,’ Chinelo said. Cautiously she probed again with her booted toe.

  Asher said, ‘There’s room for a gradient. If the speed of this moving roadway builds up steadily towards the centre – which it probably doesn’t – step in one metre and you’d be moving at about walking pace. Another metre, double that . . .’

  ‘Lethe. So what now?’

  Nicola laughed. ‘Now we’re going to ride this river.’

  Chinelo just stared.

  Michael Poole looked around, at the engineered sky, the ground, and pointed upwards. ‘Chinelo, we don’t have a lot of choice. I’m trying to get us to a cupworld up there, on Deck Two. And we’re going the long way around.’ Now he pointed west. ‘That way is the nearest strut – a connection between Deck One and Deck Two, a vertical shaft. It’s about two and a half light-days away. That’s not much on the scale of the Wheel, only about a thousandth of the circumference. If the wheel were stationary. But it’s pretty far in our terms. Two and a half light-days out from Earth would have delivered you to the Oort Cloud. And that’s the nearest strut. The next nearest, to the east – well, don’t worry about that.’

  ‘Two and a half light-days,’ Chinelo said, frowning. ‘But if we can ride the river at six per cent of lightspeed, that will take us, umm – about forty days?’

  ‘Near enough. Well, that’s the plan. The whole point of the flow system is to deliver new hull plate around the Wheel, as seamlessly and painlessly as possible. All we have to do is hitch a ride. But that’s probably the
easy part. When we get to the strut, we’ll need to climb it. Luckily for us there’s a river flowing up the strut, just as it flows along the deck, though the speed seems to be a lot slower. The distance up to Deck Two is only about a light-minute, but we think it might take us ten days to climb that high.’

  Chinelo frowned. ‘Going straight up? But we can’t drive that way. It would be like driving up a wall.’

  Jophiel grinned. ‘Don’t worry. If we get that far, we’ll think of something.’

  ‘OK,’ Poole said now. He pointed up, at the line of Deck Two above their heads. ‘So we hitch a ride up the strut, and then we’ll have to ride the river that runs along that deck, all the way to the cupworld, which is a thousand astronomical units, more than five light-days, to the east of us.’

  ‘And then?’

  Nicola smiled. ‘The cupworld. More footprints and flags.’

  Chinelo seemed to think the whole thing through. Then she said: ‘I’ll believe it when I see it.’

  At first, at least, the plan unfolded pretty much as intended.

  It was on the nineteenth day of the expedition that they had found the river. They spent a day on cautious experimenting. Mapping and measuring. It turned out the river’s speed gradient was smooth but not simple; there were stretches of relative stillness swept along by the wider flow, like huge invisible rafts. Driving a truck over the river itself was tricky, as that differential flow caused the wheels to slew. But you could park up in comfort on a ‘raft’, and just ride. The feature was so useful that Asher speculated it was designed this way, that the rivers had a secondary function, for the Xeelee itself, as a crude cargo transport system.

  When they were satisfied, the convoy trundled forward. It took another day or so to reach a raft close to the river’s centreline. That generous six per cent lightspeed was not enough to create any relativistic effects visible to the unaided senses. Indeed, even at this speed, the Wheel was so gross in its large scale, so featureless on the small scale, that there was no real sense of motion at all.