Redemption Ark

‘It would be very dangerous, Ilia. We’re safe now. We haven’t done anything to provoke the Inhibitors. Using the cache… even a single weapon from the cache…’ The Captain trailed off. There was absolutely no need to labour the point.

‘It’s a bit on the risky side, I know.’

‘A bit on the risky side?’ The Captain’s chuckle of amusement was like a small earthquake. ‘You were always one for understatement, Ilia.’

‘Well. Are you going to help me or not, Captain?’

After a glacial intermission he said, ‘I’ll give it quite some thought, Ilia. I’ll give it quite some thought.’

That, she supposed, had to count as progress.

CHAPTER 26

There was almost no warning of Skade’s strike. For weeks Clavain had expected something, but there had been no guessing the exact nature of the attack. His own knowledge of Nightshade was useless: with the manufactories aboard a military lighthugger, Skade could weave new weapons almost as quickly as she could imagine them, tailoring each to the flexing demands of battle. Like a crazed toymaker, she could spin the darkest of fabulations into existence in mere hours, and then unleash them against her enemy.

Zodiacal Light had reached half the speed of light. Relativistic effects were now impossible to ignore. For every hundred minutes that passed on Yellowstone, eighty-six passed aboard Clavain’s ship. That time-dilation effect would become steadily more acute as they nosed closer and closer to light-speed. It would compress the fifteen actual years of the journey into only four years of shiptime; still fewer if a higher rate of acceleration was used.

Yet half the speed of light was still not radically relativistic, especially when they were dealing with an enemy moving in almost the same accelerated frame. At their fastest, the mines that Skade had dropped behind her had slammed past Zodiacal Light with relative velocities of only a few thousand kilometres per second. It was fast only by the standards of solar war. Although the mines were difficult to detect until Zodiacal Light was within their ‘volume of denial’, there was no danger of actually colliding with them. A direct collision would be a very effective way of taking out a starship, but Clavain’s simulations argued that it was beyond Skade’s capability to mount such an attack. His analyses showed that for any conceivable spread of obstacles that Skade dropped in her wake — even if she dismantled most of Nightshade to convert into mines — he could always detect the obstacles sufficiently far ahead to steer a path through them.

And yet there was a terrible flaw in Clavain’s thinking, and in the thinking of all his advisors.

The obstacle, when Zodiacal Lights forward sensors detected it, was moving much faster towards him than Clavain had expected. Relativity distorted classical expectations in a way that Clavain still did not find entirely intuitive. Slam two objects towards each other, each with individual velocities just below light-speed, and the classical result for their closing velocity would be the sum of their individual speeds: just under twice the speed of light. Yet the true result, confirmed with numbing precision, was that the objects saw each other approach with a combined speed that was still just below the speed of light. Similarly, the relativistic closing velocity for two objects moving towards each other with individual speeds of one-half of light-speed was not light-speed itself, but eight-tenths of it. It was the way the universe was put together, and yet it was not something the human mind had evolved to accept.

The Doppler echo from the approaching obstacle indicated a closing speed of just above 0.8 c, which meant that Skade’s obstacle was itself moving back towards Yellowstone at half the speed of light. And it was also astonishingly large: a circular structure one thousand kilometres from side to side. The mass sensor could not see it at all.

Had the object been on a direct collision course, nothing could have been done to avoid it. But the projected impact point was only a dozen kilometres from one edge of the oncoming obstacle. Zodiacal Light’s systems instigated an emergency collision-avoidance procedure.

That was what killed them, not the obstacle itself.