And there was more to come. From out of the ripped-open side of the mountain, a chthonic blood oozed, yellow-grey, viscous, steaming hot. It began to flow down the mountainside, spilling into rain-cut valleys.
‘That’s a lahar,’ Tilo murmured. ‘Mud. The heat is melting the permafrost – the mountain was snow-covered two weeks ago; did you know that? – making up a thick mixture of volcanic debris and meltwater. I’ve learned a lot of esoteric geology here, Lieutenant.’
‘So it’s just mud,’ said Lian uncertainly.
‘Just mud. You aren’t an earthworm, are you, marine?’
‘Look at the logging camp,’ Doel said.
Already the mud had overwhelmed the heavy equipment, big yellow tractors and huge cables and chains used for hauling logs, crumpling it all like paper. Piles of sawn logs were spilled, immense wooden beams shoved downstream effortlessly. The mud, grey and yellow, was steaming, oddly like curdled milk.
Just mud. For the first time I began to consider the contingency that we might not get out of here.
In which case my primary mission was to preserve Tilo’s data. I quickly used my suit to establish an uplink. We were able to access Tilo’s records, stored in cranial implants, and fire them up to the Spline. But in case it didn’t work—
‘Tell me about dark matter,’ I said. ‘Quickly.’
Tilo pointed up at the sky. ‘That star – the natural sun, the dwarf – shouldn’t exist.’
‘What?’
‘It’s too small. It has only around a twentieth of Earth’s sun’s mass. It should be a planet: a brown dwarf, like a big, fat Jovian. It shouldn’t burn – not yet. You understand that stars form from the interstellar medium – gas and dust. Originally the medium was just Big-Bang hydrogen and helium. But stars bake heavy elements, like metals, in their interiors, and eject them back into the medium when the stars die. So as time goes on, the medium is increasingly polluted.’
Impatiently I snapped, ‘And the point?’
‘The point is that an increase in impurities in the interstellar medium lowers the critical mass needed for a star to be big enough to burn hydrogen. So as time goes by and the medium gets murkier, smaller stars start lighting up. Lieutenant, that star shouldn’t be shining. Not in this era, not for trillions of years yet; the interstellar medium is too clean … You know, it’s so small that its surface temperature isn’t thousands of degrees, like Earth’s sun, but the freezing point of water. It is a star with ice clouds in its atmosphere. There may even be liquid water on its surface.’
I looked up, wishing I could see the frozen star better. Despite the urgency of the moment I shivered, confronted by strangeness, a vision from trillions of years downstream.
Tilo said bookishly, ‘What does all this mean? It means that out here in the halo, something, some agent, is making the interstellar medium dirtier than it ought to be. The only way to do that is by making the stars grow old.’ He waved a hand at the cluttered sky. ‘And if you look, you can see it all over this part of the halo; the stellar evolution diagrams are impossibly skewed.’
I shook my head; I was far out of my depth. What could make a star grow old too fast? … Oh. ‘Dark matter?’
‘The matter we’re made of – baryonic matter, protons and neutrons and the rest – is only about a tenth of the universe’s total. The rest is dark matter: subject only to gravity and the weak nuclear force, impervious to electromagnetism. Dark matter came out of the Big Bang, just like the baryonic stuff. As our Galaxy coalesced the dark matter was squeezed out of the main disc … But it lingered here. This is the domain of dark matter, Lieutenant. Out here in the halo.’
‘And this stuff can affect the ageing of stars.’
‘Yes. A dark matter concentration in the core of a star can change temperatures, and so affect fusion rates.
‘You said an “agent” was ageing the stars. You make it sound intentional.’
He was cautious now, an Academician who didn’t want to commit himself. ‘The stellar disruption appears non-random.’
Through the jargon, I tried to figure out what this meant. ‘Something is using the dark matter? … Or are there life forms in the dark matter? And what does that have to do with the Xeelee, and the problems here on Shade?’
His face twisted. ‘I haven’t figured out the links yet. There’s a lot of history. I need my data desk,’ he said plaintively.
I pulled my chin, thinking of the bigger picture. ‘Academician, you’re on an assignment for the Admiral. Do you think you’re finding what he wants to hear?’
He eyed me carefully. ‘The Admiral is part of a faction within the Navy that is keen to go to war with the Xeelee – if necessary, even to provoke conflict. Some call them extremists. Kard’s actions have to be seen in this light.’
Actually I’d heard such rumours, but I stiffened. ‘He’s my commanding officer. That’s all that matters.’
Tilo sighed. ‘I understand. But—’
‘Lethe,’ Lian said suddenly. ‘Sorry, sir. But that mud is moving fast.’
So it was, I saw.
The mud was filling up the valley, rising rapidly, even as it flowed towards us. It was piling up behind a front that was held back by its own viscosity. As it surged forward the mud ripped away the land’s green coat to reveal bare rock, and was visibly eating away at the walls of the valley itself. Overlaying the crack of tree trunks and the clatter of rock there was a noise like the feet of a vast running crowd, and a sour, sulphurous smell hit me.
The gush out of the mountain’s side showed no signs of abating. That front was already tens of metres high, and would soon reach the village.
‘I can’t believe how fast this stuff is rising,’ I said to Tilo. ‘The volume you’d need to fill up a valley like this—’
‘You and I are used to spacecraft, Lieutenant,’ Tilo said. ‘The dimensions of human engineering. Planets are big. And when they turn against you—’
‘We can still get you out of here. With our suits we can get you over that bridge and to the transport.’
‘What about the villagers?’
I was aware of the woman, Doel, standing beside me silently, just waiting. Which, of course, made me feel worse than if she’d yelled and begged.
There was a scream. We looked down the ridge and saw that the mud had already reached the village’s lower buildings. A young couple with a kid were standing on the roof of a low hut, about to get cut off.
Lian said, ‘Sir? Your orders?’
I waited one more heartbeat, as the mud began to wash over that hut’s porch.
‘Lethe, Lethe.’ I ran down the ridge until I hit the mud.
On the mud’s surface were dead fish that must have jumped out of the river to escape the heat. There was a lot of debris in the flow, from dust to pebbles to small boulders: no wonder it was so abrasive.
Even with the suit’s strength augmentation the mud was difficult stuff to wade through – lukewarm, and with a consistency like wet cement. The stench was bad enough for me to pull my visor over my mouth. By the time I reached the cottage I was already tiring badly.
I found the little ‘family’, parents and child, terrified, glad to see me. The woman was bigger, obviously stronger than the man. I had her hold her infant over her head, while I slung the man over my shoulder. With me leading, and the woman grabbing onto my belt, we waded back towards the higher ground.