Cold.

  Suit lights off, beacons off, cryo deep-preservation option. With any luck you might evade the invader. And at least there’ll be a chance of being picked up some time in the future. By somebody. A slim chance is better than none.

  Get out of there …

  Evasion protocol …

  With the last of his will-power, the last of his consciousness, he watched the giant invader closing on a dwarfed, helpless, overwhelmed Alliance Patrol craft.

  … Your turn now, Ulla …

  … At least I proved the dark-matter ram works …

  … Hey. Suppose the suit does preserve me. Suppose the cryo works. Suppose somebody does find me, drifting without beacons … If I live through this …

  … Slim chance …

  … I made first contact. I’ll be famous. Ideally not dead and famous …

  … And if I manage not to die, maybe my report will be the saving of the 45 …

  … How about that, Ulla … ?

  … The best I can do …

  … And, you raiders, who broke my ship.

  I’ll be back.

  EXCERPT from The Hierarchy-Alliance War:

  A Personal View

  By

  Admiral Fels Sedhi

  What must be recognised is that this devastating interplanetary conflict was essentially shaped, determined, by the cosmic geography of the Hearthspace, and the human geography that followed.

  From a young age, our citizens understand that the bright light in the sky is not an ordinary star like those other, distant lanterns in our skies – like the Sun whose light has nurtured all mankind, save our star-travelling ancestors and ourselves. The Hearth is a dark matter star, fuelled not by the fusion of hydrogen but by the burning of dark matter: that elusive, intangible, invisible material that constitutes most of the mass-energy of our galaxy – indeed our universe.

  And, fuelled by a different physics, the Hearth, our local dark matter star, has a different constitution. It is much more massive – perhaps a million times as much as our Sun. And its luminosity – its brilliance, the heat and light it gives – is as much as a billion suns.

  This has consequences for the planets of that ‘sun’. And there are many of those planets, we believe perhaps millions, large and small – just as the Hearth has a million times the mass of the Sun which has a mere handful of worlds, including fecund Earth, mighty Jupiter. All is to scale.

  And in our skies are planets of the kind our ancestors explored in our home solar system, and other stars: Earths, Jupiters, etc.

  Lots of them.

  But their distributions are quite different from the Sun’s.

  There are Earths in the Hearth’s ‘habitable zone’, where the Hearthlight’s intensity is just right to nurture a living, Earthlike world. Just as the Sun has a habitable zone. But the solar system has a mere three habitable or near-habitable worlds, in Venus, Earth and Mars, with the radii of their orbits of the order of Earth’s own life-giving distance from the Sun: a distance we call an ‘astronomical unit’, one AU. At its closest to Earth, Mars comes to within a half of an AU; Venus’s orbit is about seven-tenths of an AU.

  Hearthspace has many such planets. But, numerous as they are, so huge is Hearthspace, so brilliant the Hearth itself, that the spacings of such worlds are much wider than the distances that define the solar system.

  Around the Hearth, a typical Earth-type and a typical Mars-type may follow orbits with radii as much as thirty thousand astronomical units – and so such distances have to be spanned regularly by an interplanetary culture, from an Earth to a Mars.

  Jupiter, by comparison, the first of the outer solar system’s giants of rock, ice and water, is five astronomical units from the Sun – and an equivalent orbit in Hearthspace would map onto some hundred and fifty thousand astronomical units.

  These monstrous distances can be spanned, however, by capturing the energy of the Hearth itself.

  Once humans sailed on the light of the Sun, for sunlight itself has a pressure – tiny, but sufficient to push substantial craft, given wide enough sail.

  Now, in Hearthspace, humans – Alliance or Hierarchy, slave or free – travel in sail ships, with monstrous sails that catch the light of the Hearth. Such craft massing a thousand tonnes, with a lightsail a thousand kilometres across, could pull its cargo at an acceleration of a standard Earth gravity – obviously a comfortable regime for human passengers.

  And such craft, never refuelling, can make epic journeys – especially when relativistic effects are taken into account. At one gravity, thirty thousand astronomical units could be spanned in five hundred days – as measured aboard, but more in the outer universe, given relativistic effects at such speeds.

  And in a Hierarchy craft, crossing a typical hundred and fifty thousand astronomical units could be spanned, as measured aboard, in a mere three years, four in the external universe.

  And thus the first Hearthspace War unfolded, humans, free and enslaved, with craft under monstrous sails, taking years-long voyages across enormous gulfs of space …

  2

  Aboard the sail ship, Alliance of Earths Patrol 45, Commander Ulla Breen happened to be on her watch when the first formal encounter was made between the human populations of the inner worlds of Hearthspace, and those of the outer.

  It was quite a moment, when she had a breath to think about it later. The first reunion since a presumed common origin – a single landing of humans on a Hearthspace world – and later divergence, both events lost in time.

  But all she knew of it at first was the enigmatic reporting by and loss of Fels Sedhi, and a silent flaring of alarm flags across her work station. To which none of her senior colleagues, and her captain, seemed to be aware.

  Alarm flags.

  Ulla didn’t need to scan her station to know that the ship was losing impulse, acceleration. She could feel it. They weren’t slowing down, but they weren’t speeding up either. Quite a trick to lose propulsion in a lightsail craft in empty space, with no world or moon or debris cloud to cast a shadow – nothing to shield the complex sail from the light of the Hearth, the centre of Ulla’s universe.

  Nothing. Or at least nothing she knew about, yet.

  And nor, she saw, glancing across the bridge, did her captain know about it – Frith was spinning some elaborate yarn for a handful of buddies from among his small crew.

  Given their levity, they couldn’t have paid proper attention to the Fels situation, not sufficiently, even during his dark energy prototype trial. Let alone what was going on now.

  Still, even so, whether the captain paid attention or not yet, the instruments told her they were losing their light. Bad news for a ship propelled by a lightsail.

  On impulse, Ulla looked out of a port to see for herself, beyond the instrument readings.

  And saw the sail of the 45, slowly but visibly collapsing … Shadowed, and collapsing. Possibly the same anomalous shadow that had swallowed up Fels’ boat?

  She was focusing better than the captain and his cronies, but she took all this in with difficulty.

  She was strapped into her station here on the bridge of Patrol 45 – the sail-borne ship that had been her world for a whole year – and at the same time, in her head, ran through a litany of routine, fast checks. Ulla was no specialist pilot, but as a junior officer she had learned to read the ship, its moods, its behaviours.

  A few other crew, those at their consoles, were responding similarly to the alarms, examining, seeking explanations for the anomalies – even sending each other notes, trying to figure it out.

  And now it came to a point where she began to feel the loss of thrust.

  She tried to think.

  No rogue moons around to cast shadows, to block out the light, essential for a lightsail ship. She knew that. So, what was going on?

  She risked a glance back to the command station.

  The captain wasn’t paying attention.

  And, aside from these few urgent voices – the flashing of messages on a few consoles – all seemed calm around the roomy bridge. Especially the officers on their watch in their green uniforms, a contrast with the cooler greys of the walls and ceiling. Nobody seemed concerned, except the lower ranks at their stations …

  To be fair, a general calmness was, she had long thought, an artefact of the simplicity and smoothness of their main propulsion system. It was a starlight sail, just a big sheet of a smart, sophisticated ultra-lightweight carbon fibre, simple and uniform, and equipped with an artificial intelligence of its own. Any faults were generally simple too, and typically took a while to manifest fully, given the sail’s dimensions.

  And perhaps it was a subconscious reaction. On a sail ship, unusual incidents, welcome or not, generally unfolded slowly, for good or ill. Things never happened quickly.

  Until they did.

  So the bridge didn’t need to be a crowded place usually, or full of urgency. Just a handful of on-duty monitors of Ulla’s own rank or thereabouts, leisurely checking over systems such as life support, cargo handling …

  But now, today, on Ulla’s watch, those alarm signals. And people were still slow to react. Even the news about the loss of signal from Fels hadn’t caused much apparent alarm. Nobody else seemed to be looking outside, either through monitors or even the few transparent panels cut into the wall, a fallback to allow the bridge crew to see out if all else failed … As if she was the only one who had followed that saga …

  Again she looked for the captain.

  Captain Mason Frith was eating a sandwich. Purloined from the hold, no doubt, from frozen food samples supposedly being hauled to the struggling pioneer colony on Mars 5.

  Eating, and now sharing some kind of joke with Commodore Siri Mott, his own immediate superior. One purpose of this mission was to take Commodore Mott on her official visit to Mars 5. Mott didn’t seem over-impressed with Frith, but she smiled politely enough.

  Though she did cast a glance over at Ulla, and the various unhealthy boards – and, Ulla realised, mirrored her own frown.

  Ulla looked again over her own readouts. A continuing pattern was emerging now, she saw. They were still losing tension in the sail stays. A progressive failure, it seemed, working through the array of lines.

  Something was very wrong.

  Nothing was supposed to go wrong on a ship like the Patrol 45. Sail ships were huge, and very capable, but they were so simple there was nothing much to go wrong. Nothing much but losing your light, the wind of photons that blew you from world to world.

  Nothing to go wrong with the propulsion anyhow; human factors were always a mess.

  This was just a regular year-long run – or should have been – from Earth 6 to Mars 5, the third such trip Ulla had made on 45, and her first since her promotion to the giddy heights of commander.

  Commander. One irritating step below captain. Patience, Ulla. Although maybe you’ll make that step up sooner than you think if the current incumbent on board 45 continues to foul up in small ways and large, all under the stern eyes of a commodore …

  For now though, Ulla was a senior in the bridge crew on this diplomatic (Mott) and experimental (the dark-matter drive) mission, an easy posting that had given her more flight time, and a chance to bone up on her navigational expertise and her personnel management skills. Learning how to run a twenty-strong crew that was a mix of veterans and youngsters like herself, while guiding the ship itself behind its thousand-kilometre-diameter lightsail.

  A sail that patiently, steadily gathered in the light of the Hearth – the monstrous super-star that warmed and illuminated a swarm of a million worlds, many of them habitable, or more or less so. It was on one of these that Ulla had been born two decades before.

  With a sail of the class of this fast Patrol ship, given the pressure of the steady light from the Hearth, you could cross the void from Earth 1 to Mars 5, say, and back again, in seventy standard days, with acceleration a standard gravity: three hundred astronomical units each way. Easily achievable.

  Easily …

  Later she would think that stream of thought was a kind of premonition of what was shortly to come. A bit of complacency that was bound to be punished by fate.

  The captain was making more jokes.

  Meanwhile, still that stubborn set of anomalies persisted. The strange encounter of Fels in his prototype, still to be analysed. The loss of Fels’s signal. What must the captain be thinking about that? Let alone the anomalies in the lightsail tensions …

  Had he even been following the dialogues around Fels and his aborted mission?

  Focus, Ulla. Never mind Fels, for now.

  Think.

  What would a competent captain ask her about what she was seeing in her boards, specifically? What would they want her to report?

  ‘Wider,’ she muttered to herself. ‘Whatever is casting a shadow over us – if that’s what the problem is – look, it’s wider than our sail, which is two thousand kilometres across. One of the biggest in the fleet. And we’re falling into a shadow of something so much bigger… You wouldn’t think anything save a major body, an asteroid even, would cast such a shadow, even a rogue moon. We’d see its gravity if nothing else … ?’

  ‘Looks like you’re right.’

  The voice, right behind her, made her jump.

  Reluctant to take her eyes off her instruments, Ulla glanced around.

  Commodore Siri Mott was at her shoulder, her uniform crisp, body stiff as if standing to attention, bracing her position against the ship’s current station-holding microgravity thrust with one hand. Her hair, under her cap, was streaked with silver.

  Mott prompted, ‘Problems, Commander?’

  Startled, Ulla reflexively looked around for Captain Frith, her immediate superior. Chain of command.

  But Captain Frith was still paying no attention to the readings he ought to be seeing, loaded up from Ulla’s own station and others. He was still clowning for the benefit of a handful of young officers, some looking sycophantically amused, some bored, some faintly disgusted. Or maybe they were all disgusted and just hid it well, for the sake of their careers …

  Ulla turned away. She was wary. Captain Frith was not a man who welcomed his junior officers talking to ranks over his head. So he wouldn’t approve of Mott and Ulla having any conversation that didn’t include him. Or was about him. If he even noticed, granted.

  But here was Mott looking at her anyhow. And the commodore seemed to perceive what Ulla was thinking.

  ‘Problems?’ she asked again, more softly. ‘I’m reading your expression. You’ve a problem. You’re hesitant. You haven’t seen anything like this in your training. You spotted it nevertheless.

  In the circumstances, you’ve a right to jump the chain of command. Speak freely. That’s an order.’

  Ulla felt a vast relief. ‘Yes.’

  ‘Yes, what?’

  ‘Yes, Commodore—’

  ‘Yes, the problem, you dummy. Speak freely.’

  ‘Yes, Commodore – sorry.’ Ulla began to skim through her recent readouts, pointing at various features. ‘You see, it’s this arc of our circular sail where I’m detecting a loss of pressure. Hearthlight pressure, I mean.’

  She hesitated, hoping that Mott had a technical enough background to be able to interpret what she saw, without Ulla having to say it out loud.

  Evidently not.

  Mott sighed. ‘It’s been a long time since I sat in a seat like yours, Commander Breen. And I never much got the intricacies of lightsailing. I’m a people person, even though most people I ever worked with would deny it. But—’ She held out her hand, palm up, in the light of a lamp. ‘I know the basics. I do know that light, falling, bouncing off a reflective surface, pushes at that surface. Like the rain that falls on Venus 2, as I learned to my dismay on my previous assignment.

  ‘I did read once that the force exerted by sunlight on an open human hand – the light of Sol, the old Sun, the original Sun of humanity, of legend anyhow – if you were standing on old Earth, the original Earth – the light pressure would have been about the weight of a single eyelash on your palm.’ She smiled. ‘I liked that. Poetic, but meaningful. And the light pressure from the Hearth this far out, I mean its intensity, is about the same, correct? Which is why we need such big, expansive sails …’

  Ulla knew she was being artfully put at her ease, but it was working anyhow. ‘Our sail has a diameter of two thousand kilometres, Commodore. And yes, sir, out here the light pressure our sails get from the Hearth is similar to that of Sol at Earth. A thousand times the distance of Sol from Earth. So the records tell us.’

  ‘The records,’ Mott said. ‘Ancient, fragmentary records, some of it even preserved only by word of mouth, much of which many scholars refuse to believe. But still such numbers serve well as a common frame of reference. If Earth Zero existed at all. We’re still depending on the wisdom of those ancient folk, a thousand years dead or more, those who crossed the gulf from legendary Earth to this place. Wisdom of the ancients, or just legend? If they existed at all. Maybe we have some other, much stranger origin story. We can’t be sure. Comforting, isn’t it?’

  ‘Yes, Commodore. And now, compared to what we think we know about the original solar system, we have the Hearthspace, which is a different beast altogether. Which is why we all have to live at least the square root of a billion times further out than old Earth from its Sun.’

  Mott grinned. ‘A bit smart-ass, but well put.’

  ‘I learned that much at the academy, sir.’

  ‘And here we are in this place with so much room for so many planets – all those Marses and Earths, and Mercuries and Venuses and moons … We understand it all. Even if we haven’t explored it all. One day … We adapted our solar-sail technology for this environment, but that’s not to say we don’t find problems, novel or otherwise, from time to time. Such as now. And this is why I’m gabbling now. A technique I’ve developed over time with people – with smart people who have got conceptually stuck, as you seem to be. If you have a tricky problem, talk about it. Or rather, talk around it. And from somewhere in the back of your head the answer will float to the front.’