‘Nonsense, they’d have to be metallic hydrogen to maintain their structural integrity under these conditions.’
‘So? It’s metallic hydrogen. Apart from those glowing ones; I’d say they were exotic matter. There’s virtually no infrared emission coming from in there.’
‘Is the outer shell complete?’ Oscar asked. ‘I mean is there a corresponding hemisphere on the inside of the barrier, or is this just some giant bearing groove for those lattice spheres?’
‘Good question,’ Tunde said. ‘Anna, can you focus the satellite telescope through those grids?’
‘No sir, no way,’ she exclaimed. ‘That haze effect around the third sphere is like looking into a gas-giant cloudscape, and it gets thicker below it.’
‘Like oil,’ Oscar muttered. ‘It lubricates the gaps between the spheres.’ He realized Tunde was looking at him and smiled an apology. ‘Just a thought.’
‘Anna,’ Wilson asked. ‘Will the satellite survive in there?’ She let out a long breath as she stared at the main image on the twin portals. ‘I don’t see why not, certainly as far down as the first lattice sphere, anyway. The sensor returns we’ve got show clear space that far in.’
‘Okay then,’ Wilson said slowly as a sense of real enthusiasm grew inside him. ‘Let’s do it.’
*
Anna launched a second Galileo-class satellite, flying it to the entrance hole at the top of what the crew now all called the Dark Fortress. Once it arrived, she sent the first satellite inside, using the second as a relay. As it descended towards the outermost lattice sphere the energy surges around the satellite picked up noticeably. Eventually, Anna stopped trying to compensate. At that rate she would run out of fuel in a matter of hours. So she let the little craft wobble its way forward, blurring the visual sensor pictures. Every eighty kilometres or so she would stabilize it again, and run a quick check before allowing the vibrations to build up. There was nothing to see en route. The gap between the outer shell and the first grid sphere was empty, with the satellite sensors recording it as a hard vacuum.
When it was halfway there, one of the sphere’s massive struts slid underneath the hole, eclipsing the light pouring up from the inner lattice spheres. By now the crew were successfully recording the geography of the first lattice, and were making good progress charting the second. There seemed to be no logic behind the pattern. But predicting the times of the eclipses was now straightforward.
As the satellite grew nearer to the first lattice sphere, the radar return began to improve. ‘That’s odd,’ Anna remarked as she stabilized the satellite once again.
‘Problem?’ Tunde asked.
‘I’m using parallax to confirm the distance to the strut we’re heading for, but there’s a discrepancy between that and the radar return. Radar places it three klicks closer.’
‘Maybe that optical haze effect is throwing the parallax reading?’
She shook her head. ‘Clear view. There is no haze round these struts.’
The discrepancy began to rise as the satellite closed in. Then they examined the magnetic flux around the strut, seeing the force lines warp like cyclone clouds around the surface.
After a long and heated conference with the rest of the physics team, Tunde said: ‘Whatever else it is, the outer lattice sphere has electro-repulsive properties. The radar pulses aren’t actually reaching the surface itself.’
‘Can we take the satellite in and attempt a landing?’ Wilson asked.
‘I wouldn’t recommend it. That repulsion force would play havoc with the electronics. We’ll have to study it from a distance.’
*
The Galileo satellite spent two days hovering thirty kilometres above the first lattice sphere as it rotated slowly underneath. All of its sensor booms were fully extended, gathering up as much information as possible. Back on the starship, the physics team worked with the engineers to try and design a simple probe which they could drop onto one of the struts. Its circuitry was all optronic, using a laser for communication; sensors were extremely limited. But even studying its flight path as it neared a strut would tell them something.
Wilson, keen to expand the exploration of the Dark Fortress, authorized its deployment. A further two Galileo-class satellites were launched. Anna and Jean Douvoir had assembled a small team of controllers drawn from the pilot-qualified on board to help them remote-fly the probes. Together, they steered the twin satellites through the entrance hole, and took them down towards the first lattice sphere. Anna manoeuvred the lead one into the centre of a pentagonal-shaped grid and, while Jean held the original satellite fifty kilometres above as a communications booster, she fired its ion thrusters, flying it straight in towards the second lattice sphere. As it passed through the level of the struts, electronic systems suffered repeated crashes. Thankfully the multiple redundancy architecture managed to keep the primary components on line the whole time, constantly rebooting the failed units. It released the probe and carried on.
Once it fell below the outermost lattice sphere the Galileo returned to full functionality. Heartened by that, Anna got another of her team to send the second satellite through. With both of them clear and operational, she took them in deeper still.
The probe, meanwhile, drifted steadily towards its target strut. Information zipped back along the laser link, revealing the swirling energy environment around the vast mass. Contact was lost a couple of minutes before impact. The physics team wrote that down to the repulsion force affecting the probe’s battery.
Anna’s team piloted the two Galileo satellites in towards the second lattice sphere. As they receded from the first, so the magnetic and electromagnetic squalls shrank away. It began to look as though the second lattice sphere was inert. With one satellite holding back, poised halfway between the two, Anna lowered hers in towards the edge of a strut making up a large pentagon shape. Radar return was precise, there was no magnetic field, no electromagnetic emission, the infrared signature was minute.
‘Something’s slowing it,’ Anna reported. The satellite’s velocity was dropping at an increasing rate, as though it was encountering some kind of atmosphere. Molecular sensors stubbornly continued to report a vacuum outside.
Anna managed to get it to within seventy kilometres of a strut surface before it came to a complete halt. She had to fire the main thrusters at full strength simply to keep it there. Without that, the satellite would have reversed its trajectory. ‘Something’s pushing it away,’ she told the physics team.
After three days of attempted approaches at varying velocities, another Galileo satellite arrived to assist, equipped with a simple rail launcher to shoot inert slugs of different elements. It began firing. Every slug, no matter what its component atoms, slowed to a halt before reaching the strut, then began to return, picking up speed. Complemented by both passive and active sensor sweeps of the second lattice sphere, the physics team came to their excitable conclusion: ‘Negative mass matter,’ Tunde announced at the next meeting of department heads. ‘Its gravitational force is the opposite of our own, therefore anything made out of ordinary matter will always be repelled.’
The satellites were able to push through the centre of each hole in the negative mass lattice where the inverted gravity was at its weakest. Anna moved one down to the next level, dipping it into the shoal of tiny pale scintillations that swirled across the gulf between the second and third lattice spheres. Its sensors had trouble tracking the dense will-o’-the-wisps; but eventually the physicists determined it was a tenuous cold plasma, aggravated by the emissions of the exotic matter below, and confined to the gulf by the negative mass above.
Analysing the exotic matter proved even more difficult than the previous two lattice spheres. They had to launch a whole squadron of large Armstrong-class satellites with their powerful and comprehensive sensor suites. It took a further two weeks before they’d charted the energy currents seething like photonic tempests in the plasma between the two exotic matter spheres. After that,
there was enough confidence in their newly acquired knowledge to pilot a satellite through the fourth lattice sphere.
When the first Armstrong satellite passed through it found no further spheres. Instead, the space in the middle, measuring sixteen thousand kilometres in diameter, housed a series of concentric rings, all of them aligned with the plane of the barrier outside. The outermost, thirteen thousand kilometres across, the crew immediately named the daisy chain. It was a sequence of lenticular disks linked together by a black cable. Next in was a simple ring of green matter, so smooth and uniform it was impossible to tell if it was rotating. A braided ring whose thick silver strands moved sinuously around each other like oiled serpents. One of pure scarlet light. More solid loops. The globes, hundreds of thousands of them, strung together in a dense necklace that the bridge officers likened to a strand of alien DNA, twisting round each other as they rotated round the centre. Sparks: a wide band of emerald and amber lightpoints trailing cometary tails as they orbited in both directions, though never colliding. There was one of water, or some clear liquid, with a surface beset by waves. Right in the centre was emptiness, a little patch of darkness into which light fell.
It was God’s own orrery.
Talk in the starship’s canteen was that the lattice spheres powered the rings, or vice versa. Either way, they were all convinced now that the Dark Fortress was the barrier generator.
One by one, the satellites were ordered down towards the rings. One by one they lost contact with the Second Chance. The centre of the Dark Fortress was an energistic maelstrom. Human technology could not survive within it. Watching the displays that showed tides of quantum distortions raging chaotically around the wounded satellites, some of the physics team claimed the rings didn’t – couldn’t – even exist in normal spacetime.
What everybody on board wanted to know was if there was a corresponding opening on the other side of the Dark Fortress.
‘There’s no way we can get anything across the centre and past the rings,’ Tunde said. ‘If we’re going to try this, we’ll have to program a satellite to fly round in the gulf between the outer shell and the first lattice sphere. It’ll have to operate in autonomous mode, we don’t have enough satellites to act as a relay chain over that distance.’
‘It’s a waste of time,’ Oscar said. ‘I don’t believe there’s a hole there. There’d be no damn point to the whole barrier if there was.’
‘I don’t think there is either,’ Wilson said. ‘But you know we have to look. Anna, program a Galileo for the assignment.’
The flight took three days. When the Galileo re-emerged into communication range, its sensor logs showed the shell opposite the hole was continuous. It had searched over twenty thousand square kilometres. Wilson ordered it to be refuelled, and sent it out again. After seven flights, it had scanned the entire hemisphere on the other side of the barrier. There was no hole, no passage through to the imprisoned star.
*
Three months after they discovered the Dark Fortress, Wilson called Oscar and Tunde to his cabin for a mission conference. ‘I need to know if we’re going to learn anything more from the Dark Fortress,’ he said to Tunde.
‘Are you joking?’ the surprised physicist asked. ‘There is more exotic physics in there than the human race has discovered since an apple fell on Newton’s head.’
‘I’m sure there is. But now we have the major components identified, how much can you and your team realistically add to that? I mean, we don’t even know if this really does generate the barrier.’
‘It’s a logical conclusion.’
‘Admittedly, yes. But can you prove it? More importantly, can you prove it with the sensors and instruments we have available on board?’
Tunde looked defiant for a moment, but eventually nodded reluctantly. ‘No. Not a chance, really. As you say, we can map what’s there. But determining function and interconnectivity . . . On this scale, it’s the kind of project which would absorb every living theorist for the next two centuries. We need a bigger ship, in fact we need to establish an outpost the size of the High Angel, and with its manufacturing capacity. The Commonwealth will have to open a chain of wormholes out here, that’s the only way we can apply the kind of resources we need to crack this.’
‘It’s not going to happen,’ Oscar said. ‘Oh I agree, it should. But from a political point of view, all you’ve got here is the mother of all esoteric physics problems. That doesn’t gain you the kind of funding you’re talking about.’
‘Nigel Sheldon will understand,’ Tunde said.
‘Yes, he will,’ Wilson said. ‘More than anybody, he made this flight possible. But even he can’t carry the entire Commonwealth Senate, not for that kind of financial commitment. If we’d found anything out here, anything that indicated why the barrier was established, any hint of a current threat to the Commonwealth, then we might earn ourselves a couple of return missions at the very least. But it’s an enigma. And we’ve lived with enigmas for a long time now. We’re shocked and excited by them at first, then we just learn to live with them. Eventually, we don’t even question them any more. Look at the Silfen. Why don’t electronics work on their worlds? How the hell do they really travel between star systems? Our popular myth has it there are forest paths between worlds. That’s what the more arcane members of our race believe. More practical people believe they spread themselves across the galaxy with arkships millennia ago. It doesn’t matter, because we live with it, it doesn’t affect us. Now as far as we can determine, the barrier, for all its grandeur, isn’t going to affect us either. There are no alien battle fleets waiting out here to blow Earth to pieces and steal our gold and our women. This is just one more incomprehensible relic that will take us five hundred years to understand. One day, after that, you and I will be standing here and laughing at how puzzled we once were.’
‘You’re taking us home, aren’t you?’ Tunde realized.
‘Not immediately. But we’ve certainly devoted enough time to the Dark Fortress. Unless either of you have a viable alternative, I’m going to continue with our flight around the barrier. After that, if there’s nothing else to be found, we’ll examine the poles as originally planned. We might follow up with a fast examination of Dyson Beta. I’d like to confirm that it is the same before we head for home.’
‘I’ll concur with that,’ Oscar said. ‘Team leaders are getting asked how much longer the investigation is going on for. Nobody has actually complained yet, but I’d say it’s time to move on.’
They both looked at Tunde.
‘All right,’ he said. ‘We do have enough data to keep the universities busy for a decade. But I hope to God you’re wrong about the next stage of the project. Understanding the technology in the Dark Fortress would elevate our species to unbelievable heights. We could become transgalactic, for heaven’s sake; there really would be no limits to what we could achieve.’
*
Anna and her little team of controllers recalled the satellites; carefully threading them back through the moving maze that was the four lattice spheres. Out of the thirty-seven they’d deployed inside the Dark Fortress, nine had been lost, either in the centre or due to communication failure. When the remainder were back in their hangar cradles, Tu Lee sent the Second Chance back into hyperspace at a speed that would complete the circuit of the barrier in another five days.
*
The alarm brought Wilson struggling out of a deep comfort-able sleep. He floundered around on the cot for a second, trying to shield his eyes from the cabin lights which had switched on automatically. Anna groaned, squinting and blinking.
‘What the fuck—’ she grunted.
‘The bridge has declared an emergency,’ Wilson’s e-butler told him.
‘Son of a bitch!’ He rolled off the cot and headed straight for the door. His virtual vision was flashing up dozens of icons. It was difficult to focus on them and the corridor he was half-running down. Fortunately, the starship’s designers had stuc
k with maritime tradition and kept the captain’s quarters close to the bridge.
The status icons didn’t indicate any physical damage to the superstructure, and the hyperdrive was functioning normally Defence was equally reassuring. No immediate danger, then. Wilson forced himself to relax as the bridge door slid open for him. That was when he started to review the sensor icons. The hysradar was breaking through the barrier.
‘Shit!’
The bridge’s small night shift crew glanced round at his exclamation.
‘It started a couple of minutes ago,’ Oscar said as he rose from the command console chair. ‘I ordered a halt to our flight.’
Wilson glanced at the forward portals as he sat down in the command chair. ‘Are we still in the wormhole?’
‘Yes, sir.’
‘Okay, Tu Lee, plot a course directly out of here. Implement it the second I tell you.’
‘Aye, sir.’
Both portals were showing the hysradar scan of the barrier surface. It seemed to be fluctuating, bowing inwards as if it was being bombarded by projectiles. Then Wilson acknowledged the scale; if objects were hitting it, they’d be the size of gas-giants. The hostile force! The reason the barrier was established. ‘Astrophysics, do we know what’s causing that?’
‘No, sir,’ Bruno said cheerfully. ‘Not a clue.’
‘Is there anything else out here? A ship? Some weapons system which could be causing that?’
‘Nothing,’ Sandy Lanier reported from the sensor console. ‘The hysradar scan is clean for a thousand AUs this side of the barrier.’
Wilson frowned at the bridge portals. The fluctuations were growing larger. And they weren’t going to find out why sitting out here peering over the parapet. Decision time.
‘Hyperdrive, take us in to one million kilometres of the barrier,’ Wilson ordered. ‘Defence, force fields on. Let’s see what’s happening.’
The rest of the bridge day shift arrived, sitting at the consoles that had been left unmanned, or standing behind the night shift. The atmosphere of nerves and genuine excitement was the same as Wilson remembered from the Eagle II’s cabin as they came in to land. He rubbed his hand slightly self-consciously over his creased white T-shirt before brushing strands of floppy hair away from his brow; the chair’s leather was already sticking to his bare legs below his jockey shorts. For a moment he considered hurrying off to change. It was hardly the most dignified image for history (and the on-board sensors were definitely recording); but then half the bridge crew was dressed the same. Ah, what the hell . . .