He tried to summarise for Poole the geography of the centre of the Galaxy. The structure was concentric - ‘Like an onion,’ Poole commented - with layers of density and complexity centred on Chandra, the brooding supermassive black hole at the centre of everything. The Core itself was the Galaxy’s central bulge, a fat ellipsoid of stars and shining nebulae set at the centre of the disc of spiral arms. Embedded within the Core was the still denser knot of the Central Star Mass. As well as millions of stars crammed into a few light years, the Mass contained relics of immense astrophysical violence, expanding blisters left over from supernovas, and tremendous fronts of roiling gas and dust thrown off from greater detonations at the Galaxy’s heart. Stranger yet was the Baby Spiral, a fat comma shape embedded deep in the Mass, like a miniature galaxy with its own arms of young stars and hot gases.

And at the centre of it all was Chandra itself, the black hole, a single object with the mass of millions of stars. The Galaxy centre was a place of immense violence, where stars were born and torn apart in great bursts. But Chandra itself was massive and immovable, the pivot of vast astrophysical machineries, pinned fast to spacetime.

Poole was intrigued by Futurity’s rough-and-ready knowledge of the Core’s geography, even though the acolyte had never before travelled away from 478. ‘You know it the way I knew the shapes of Earth’s continents from school maps,’ he said. But he was dismayed by the brusque labels Futurity and the crew had for the features of the centre. The Core, the Mass, the Baby: they were soldiers’ names, irreverent and familiar. In the immense glare of the Core there was no trace of mankind’s three-thousand-year war to be seen, but those names, Poole said, marked out this place as a battlefield - just as much as the traces of complex organic molecules that had once been human beings, hordes of them slaughtered and vaporised, sometimes still detectable as pollutants in those shining clouds.

Something about the location’s complexity made Poole open up, tentatively, about his own experience: the Virtual’s, not the original.

‘When I was made fully conscious the first time, it felt like waking up. But I had none of the usual baggage in my head you carry through sleep: no clear memory of where I had been when I fell asleep, what I had done the day before - even how old I was. The priests quizzed me, and I slowly figured out where I was, and even what I was. I was shocked to find out when I was. Let me tell you,’ said Poole grimly, ‘that was tougher to take than being told I was worshipped as a god.’

‘You can remember your past life? I mean, Poole’s.’