I wasn’t convinced. ‘You can change history. But you will still send Tarco out, knowing he will die. Why?’

Varcin’s face worked as he tried to control his irritation. ‘You must understand the decision-making process here. We are trying to win a war, not just a battle. We have to try to see beyond individual events to the chains of consequences that follow. That is why we will sometimes commit ships to a battle we know will be lost - why we will send warriors to certain deaths, knowing their deaths will not gain the slightest immediate advantage - why sometimes we will even allow a victory to turn to a defeat, if the long-term consequences of victory are too costly. And that is at the heart of the charges against you, Captain.’

Dakk snapped, ‘Get to the point, Commissary.’

Varcin gestured again.

Before the array of futures, a glimmering Virtual diagram appeared. It was a translucent sphere, with many layers, something like an onion. Its outer layers were green, shading to yellow further in, with a pinpoint star of intense white at the centre. Misty shapes swam through its interior. It cast a green glow on all our faces.

‘Pretty,’ I said.

‘It’s a monopole,’ said Dakk. ‘A schematic representation.’

‘The warhead of the Sunrise torpedo.’

‘Yes.’ Varcin walked into the diagram, and began pointing out features. ‘The whole structure is about the size of an atomic nucleus. There are W and Z bosons in this outer shell here. Further in there is a region in which the weak nuclear and electromagnetic forces are unified, but strong nuclear interactions are distinct. In this central region’ - he cupped the little star in his hand - ‘grand unification is achieved.’

I spoke up. ‘Sir, so how does this hurt the Xeelee?’

Dakk glared at me. ‘Ensign, the monopole is the basis of a weapon which shares the Xeelee’s own physical characteristics. You understand that the vacuum has a structure. That structure contains flaws. The Xeelee actually use two-dimensional flaws - sheets - to power their nightfighters. But in three-dimensional space you can also have one-dimensional flaws - strings - and zero-dimensional flaws.’

‘Monopoles,’ I guessed.

‘You got it.’

‘And since the Xeelee use spacetime defects to drive their ships—’

‘The best way to hit them is with another spacetime defect.’ Dakk rammed her fist into her hand. ‘And that’s how we punched a hole in that Sugar Lump.’

‘But at a terrible cost.’ Varcin made the monopole go away. Now we were shown a kind of tactical display. We saw a plan view of the Galaxy’s central regions - the compact swirl that was 3-Kilo, wrapped tightly around the Core. Prickles of blue light showed the position of human forward bases, like Base 592, surrounding the Xeelee concentration in the Core.