Xeelee Redemption

by Baxter, Stephen

  Normal. Depending on your perspective, Jophiel supposed. Beyond the lifedome’s apex was a mush of stars and glowing gas. This was no projection now, Jophiel knew; this was a naked-eye view – if any unprotected human could have survived out there, in the sleeting radiation of the Galaxy Core.

  ‘What a view,’ Jophiel said to Poole. ‘And what an achievement. We made it, Michael. Whatever comes next, we made it.’

  Poole, glaring up at the crowded sky, looked fierce. And he opened his fist.

  The Wormhole Ghost amulet, still attached to its lanyard, floated up from his palm into the air.

  ‘Michael?’

  Poole looked at his avatar. ‘Remember the image my – our – mother extracted from this thing? I showed it to Nicola on the night before we left Cold Earth for good.’

  ‘Of course I remember.’

  ‘I’ve done a lot of thinking. Nicola’s right. I’m no warlord. But I’m no criminal either. One human can’t deflect the course of a Galaxy’s history. On the other hand, that Lethe-spawned Xeelee came for me, and my planet. So I’m involved. Well, I hurt it in the Solar System, and I tracked it all the way here, and now I’m going to finish this. That’s all. Are you with me, Jophiel?’

  ‘I am you.’

  Poole magnified the sky image with a wave of his hand.

  And Jophiel saw it at last. Clearly distinguishable, against a backwash of hurtling stars.

  The object at the very centre of the Galaxy. Just as in the amulet imagery.

  Chandra.

  A black hole with a ring around it.

  The Wheel.

  35

  Ship elapsed time since launch: 19 years 259 days

  Earth date: c. ad 28,700

  The Pooles, conferring, had decided to wait a week after the GUTdrive finally died before fixing on the next step.

  There was a lot of muttering about that, Jophiel realised. It was too long a delay, according to the more hot-headed of the Pooles’ advisors, notably Nicola and Max Ward. Or it was too short, according to others.

  The Pooles reckoned they needed the time. Time to gather more detailed data than had been possible in flight. Time to run through a hasty programme of maintenance and refurbishment for the ship, after nearly ten more years of continuous thrust. Time to prepare equipment and strategies for the next phase of this lifelong mission – such as launching probes to explore the spaces around them. Time to hang, unpowered, at the edge of this extraordinary Galaxy-centre system, and just look.

  A week? Too long or too short? It would do.

  There was even more controversy when at the end of the week the Pooles announced that the next steps would be discussed at an open crew briefing.

  ‘This is nuts,’ Max Ward predictably groused as the meeting slowly assembled in the lifedome amphitheatre, the open space once more strung with zero-gravity webbing. ‘We already spent too long on this mission bouncing babies and chasing chickens. And now, what, should we have a singalong before we start?’

  Nicola had a grin on her silvered face. ‘You hum it, I’ll play it.’

  Michael Poole took the opportunity to kick her foot. By now she was showing up to these events in person once more; Max seemed to have parked his decade-old threat to have Nicola dismantled. But it didn’t pay to provoke him.

  ‘Come on, Max,’ Jophiel growled. ‘This isn’t just our war. It’s theirs.’ He waved a hand. ‘The next generation. This is only the beginning, for them. I mean, we know this isn’t the only Lethe-spawned Xeelee in the cosmos. Even if we win this battle the war has to be carried on. And that will be up to them.’

  Susan Chen, sitting patiently cross-legged on the ground, looked up at him. ‘A remarkably bleak perspective, Jophiel. So is this the future for mankind, or what’s left of it? The child soldier?’

  Max grinned. ‘If it was good enough for the Exultants, it’s good enough for me.’

  As the due time approached the crew gathered, some bringing carry-bags and baby papooses that they tied to the zero-gravity guide ropes. Michael Poole opened the meeting by simply standing up, and waiting until the buzz of talk had died down.

  ‘So,’ he said. ‘It was a long hard journey, but we got here.’ A smattering of applause, a few whoops. ‘We’ve had a week to celebrate. But now the hard work begins.’

  He clapped his hands.

  The lifedome went dark. There was a ripple of anticipation.

  And a wash of red stars appeared in the air above all their heads. Within this cloud, Jophiel thought he saw a central knot, directly over his head, a point of light brighter than the rest. There were a few brighter stars close in around that mass, like planets around a sun.

  He looked around. Saw the upturned faces of children, shining in Galaxy-centre light.

  ‘We’re close now,’ Poole said. ‘Just one and a half light years from the very centre,’ and he pointed to that Sunlike knot.

  ‘Chandra,’ replied a very young voice.

  ‘Right. The black hole. Which itself has a mass of four million stars. And within a few light years of the black hole there are around ten million stars. There’s a paradox, though. Right here, about one and a half light years out, there’s a drop off – a kind of hole within this inner star cluster. The stars are less densely packed than further out. Maybe, if an infant star gets too close, the black hole’s tides disrupt its formation. Or maybe Chandra’s gravity just slingshots stars away.

  ‘Anyhow, that’s precisely where we stopped,’ Poole said now. ‘On the edge of that inner cavity. We planned it that way, with the help of Ben Goober and his navigational tweaks. We figured this was a good vantage.’ He pointed again. ‘So there’s the black hole, and its surrounds, the accretion disc, the close-in stars that orbit it. Asher and her people are taking a good hard look at that. But we’re not going to the black hole, not yet—’

  ‘I know where we’re going.’ A young voice.

  A slim figure stood up. Jophiel recognised Chinelo Thomas, daughter of Alice, ten years old, one of the first of the new generation to be born on the Cauchy. Evidently a good kid, but, to Jophiel, a stranger, like all her generation. From the moment they’d been born, Jophiel had learned from bitter experience that, to children, Virtuals were creatures that looked like people but who you couldn’t smell or touch, and were therefore to be feared. By the time the children were starting to walk and talk Jophiel had got used to keeping a polite distance from them, and in turn they from him.

  Now Chinelo pointed upwards. ‘We’re going to the Wheel.’

  Poole nodded gravely.

  He clapped his hands again, and the image shifted, becoming a schematic. There was the central black hole, and its clutter of companion objects. Further out, the swarming red stars were reduced to pinpricks.

  And there was a ring, a fine band, enhanced and now clearly visible. Subtly tilted, it swept across the foreground, and wrapped around the rear of that central glow, slim, perfect.

  No matter how many times he considered it, Jophiel shivered with awe. It was obviously an artefact, a made thing two light years in diameter. A ring around a supermassive black hole. How could any finite living creature have the audacity to construct such a thing? But their best guess as to the origin of this thing was that, evidently, the Xeelee from the Solar System had done just that – for if the Wheel had existed before the Displacement of Earth, evidence of it would have shown up in deep-sky radio wavelength probes, probably millennia before Poole had been born. It was that big.

  The crew were silent. Jophiel saw that every face was turned up to Poole’s image – including Chinelo Thomas, who was still on her feet. And she was grinning, her perfect teeth white in the light. Again Jophiel shivered. Not because of the black-hole engineering this time. Because of this determined kid.

  Poole said now, ‘It’s going to take us some time to explore all this. You know
that. Years, even.

  ‘Think about the sizes here. The black hole itself is built on the same scale as the Solar System. It is a big ball of darkness, of twisted spacetime, and it sits at the centre of all this, like the Sun in the Solar System – but it is much bigger than the Sun. Its event horizon would just about fill the orbit of Mercury. If you saw it from Earth’s orbit its width would span eighty Suns, side by side.

  ‘Outside that is the accretion disc. A mass of rubble, mostly broken-up stars, a great whirlpool that is slowly draining into the event horizon itself. In the Solar System, that would wash beyond the orbit of Mars, or even further out; the edge isn’t well defined. And you see those close-by stars? Everything here is orbiting the black hole, and they come as close as they can get without being ripped apart by the tides. They orbit a few hundred astronomical units out – as far out as our Kuiper belt. Whole stars, orbiting like planets.’

  ‘So all this is about the size of the Solar System,’ Chinelo said now. ‘Whereas the Wheel—’ She spread out her arms.

  Asher Fennell smiled now. ‘The Wheel is a band a million kilometres wide, give or take. So wide that even at our distance of half a light year from the closest surface, there’s some detail we can make out. For instance it seems to have a couple of decks raised up above an outer substructure . . . Sorry. I get caught up on the detail. Yes, a million kilometres wide.’

  And it has a radius of a light year. It’s easy just to say that. A Wheel with the radius of a light year. So what? So the whole thing is over six light years long, in circumference. Why, if you straightened it out it would stretch from the Solar System to beyond Alpha Centauri! A single structure. Not only that, it’s also rotating. The whole Lethe-spawned thing. Rotating at near lightspeed. Very near lightspeed. And that has implications. Ask Einstein.’

  ‘So it’s big.’ Chinelo was grinning, entirely unfazed. ‘So we land on it, and take it. Right?’

  Once again, Jophiel shivered.

  36

  Ship elapsed time since launch: 19 years 352 days

  Chinelo was right. That was the ultimate goal, to land on the artefact, to engage the Xeelee. Even if nobody knew how to do that right now. Even if all they could actually conceive of, for now, was a flyby in the Cauchy.

  And even Poole didn’t believe he could risk that before gathering data from a series of probes. Launched over the weeks following engine shut-down, these were automated, each a stubby cylinder just a metre or so long.

  But the last of them, Poole decided, for this first human exploration of the environs of a black hole, was to be crewed, after a fashion: crewed by three Virtual humans, lodged within the probe’s memory store.

  It took a hundred days after the ship’s arrival at its half-light year-out station to get the mission set up, a suitable probe modified.

  And the designated crew was chosen after discussions in the apex suite. Afterwards, Jophiel was never sure if he, Nicola and Asher had volunteered or not. Nicola whispered to Jophiel, ‘You know I hate these cast-off shadows of the living. No offence. But, you thought I’d miss this?’

  So, on the hundredth day, the three of them found themselves drifting in the air, facing each other in an infirmary bay where they went through final medical checks, and Harris Kemp led them through a countdown to the spin-off. Jophiel knew the drill. The spun-off Virtuals would be stored, without activation, inside the probe’s memory for more than a year until the first significant mission milestone. This was necessarily a pared-down, energy-conscious mission. So, in a few subjective seconds, either he was going to be here still, or—

  ‘Three. Two. One.’

  37

  Ship elapsed time since launch: 21 years 24 days

  Not.

  Jophiel and Nicola shared a glance.

  Jophiel quickly checked his environment. Suddenly they were sitting in a flitter cabin. Or so it seemed. The big viewing window ahead of them showed a stripe across a complex sky. Artifice, like scaffolding, Jophiel thought.

  Asher wasn’t here, in the cabin.

  ‘Lucked out,’ Jophiel said.

  ‘You mean, to find yourself the copy on a one-way mission to oblivion? Depends on your point of view. And what in Lethe are you doing in my seat?’

  Jophiel found he was indeed sitting in the Virtual flitter’s left-hand seat, Nicola on the right. Jophiel hadn’t even noticed. He laughed.

  ‘Just my little joke.’ A disembodied voice.

  ‘Asher? Is that you?’

  ‘Mission control here.’

  ‘And as Virtual as we are?’

  ‘Indeed. I just thought I would keep from cluttering up the cabin. Not a lot of room with your two egos in there. In fact, as far as I can tell, I’m back aboard Larunda. Home from home. Orbiting Mercury, you remember? When Harris and I looked over the shoulder of Mitch Gibson as you two piloted your way down into the heart of the Sun.’

  ‘As I piloted us down,’ Nicola groused. ‘So, Poole, are you going to give me my couch back, or do I have to reprogram you?’

  Of course none of this was real, Jophiel knew. Just another couple of Virtual environments, inhabited by Virtual people, an illusion cast by a chip the size of a thumbnail within the carcass of a ship the size of a walking stick.

  And yet – here he was.

  Jophiel gave it up with good grace.

  But he felt a faint nausea as he moved. That was an unusual side-effect of a spin-off, if that was what it was. He said nothing. He hoped it would pass before the others noticed.

  ‘So,’ said Asher, with a kind of glacial calm. ‘We’re committed, however we feel about it. You want to know where we are?’

  ‘Or,’ Jophiel said, ‘more to the point, when we are.’

  ‘Yes. Timing is going to be a little tricky. In terms of our direct experience, obviously it’s only minutes, for us, since we were all sitting in the Cauchy infirmary being downloaded. We just skipped forward, in our dreamless sleep, about four hundred days. And then there are the complications of relativistic time dilation, for a probe which is travelling nearly at the speed of light while the Cauchy is effectively stationary—’

  ‘Get to the point,’ Nicola growled.

  ‘I’m planning to log ship’s time as measured at the Cauchy, as opposed to what we experience. So we are twenty-four days into year twenty-two since launch from Cold Earth.’

  Jophiel did a quick mental conversion. ‘A year, accelerating steadily. So we’ve already travelled about half a light year. Which means—’

  ‘We’re about to cross the perimeter of the Wheel. Take a look.’

  And that structure that Jophiel had glimpsed before from a respectful distance, that complicated band across the sky, now swept over his field of view.

  Huge, complex, detailed, hanging in space.

  There and gone.

  At Jophiel’s insistence, they ran the visuals and other recordings of the flyby over and over.

  Nicola grunted. ‘This Wheel is about the biggest, dumbest object anybody ever built. Or dreamed of, anyhow. And I bet you did dream of stuff like this, Poole.’

  ‘Big but not so dumb,’ Asher murmured. ‘How you could ever build such a thing is another question – although I’m picking up a few clues. Look at this. I’m selecting images.’

  In magnified images of the Wheel’s elegant, curving sweep, Jophiel glimpsed structure. Layers, like strata, raised above the floor level on the inside curve, fixed by some kind of spokes.

  ‘As we suspected there are more decks above a base level – the outermost shell, the closest to lightspeed. We’re calling that the “c-floor”.’

  ‘Cute,’ murmured Nicola.

  ‘The lowest deck, a couple of hundred metres up, is itself only a whisker below lightspeed. Call it Deck One. The effects of time dilation down there – I’m estimating the numbers, and I frankly don’t b
elieve them. After that, Deck Two is twenty million kilometres above Deck One. The decks are connected, or supported, by what look like incomplete spokes. The highest of the decks, Deck Three, is more than a thousand astronomical units up from the c-floor.’

  Jophiel tried to take that in. An astronomical unit was the distance of the Earth from the Sun. A thousand AU: you could have fit the entire Solar System, all the way out to the inner edge of the Oort cloud, between those decks. Yet, on the scale of the Wheel itself, it was all lost in the detail; the Wheel’s light-year radius was more than sixty times larger again.

  It was impossible to grasp.

  But Asher was trying to grasp it even so. ‘There are glimpses of detail on the decks themselves. Splashes of colour, discs and ellipses . . . Complex materials, evidently, contained in some kind of pits in the surface. I’m trying to compile maps. And I think I’m seeing signatures of chemistry in those pits. Some volatile compounds. Methane. Oxygen.’

  Nicola looked startled. ‘Life?’

  ‘That’s the obvious conclusion to jump to. But it is a jump . . . How could life get here?’

  ‘Maybe it was brought here,’ Jophiel said. ‘Or drifted. This artefact could be over twenty-five thousand years old, if the Xeelee came straight here by hyperdrive from the Solar System. Not old enough for life to evolve here, but time enough for it to travel. As we did.’

  Nicola, heroically, still refused to be impressed. ‘It’s just a big dumb machine. Even if it does have bugs growing in the clockwork. Anyway, how could life survive? I’m guessing the spin gravity down there is ferocious.’

  ‘Actually, not,’ Asher said. ‘Surprising, maybe. The spin gravity even on the lowest deck is only about a gravity. I mean, an Earth gravity.’

  ‘That makes no sense,’ Nicola protested. ‘That’s no spinning toy, like Larunda at Mercury. You said the rim is moving at near lightspeed!’

  ‘But,’ Jophiel said gently, ‘the turning radius is a whole light year, remember. It balances out. So if people do get to land there they will be able to walk about comfortably. You see, you can imagine wheels of varying sizes each with one-G spin gravity.’