It was towards one of these satellite black holes that the Ask Politely now descended.

Dropping into the accretion disc was like falling into a shining cloud; billows and bubbles, filaments and sheets of glowing gas drifted upwards past the ship. Even though those billows were larger than planets - for the accretion disc, as Poole had noted, was as wide as a solar system itself - Futurity could see the billows churning as he watched, as if the ship was falling into a nightmare of vast, slow-moving sculptures.

The approach was tentative, cautious. Captain Tahget said the Shipbuilders were having to be bribed with additional goodies; the swarming creatures were very unhappy at having to take their ship into this dangerous place. This struck Futurity as a very rational point of view.

In the middle of all this they came upon a black hole.

They needed the observation lounge’s magnification features to see it. With twice the mass of Earth’s sun, it was a blister of sullen light, sailing through the accretion clouds. Like Chandra’s, the dark mask of its event horizon - in fact only a few kilometres across - was hidden by the electromagnetic scream of the matter it sucked out of the universe. It even had its own accretion disc, Futurity saw, a small puddle of light around that central spark.

And this city-sized sun had its own planet. ‘Greyworld,’ Mara breathed. ‘I never thought I’d see it again.’

This asteroid, having survived its fall into Chandra’s accretion disc, had been plucked out of the garbage by the Ideocrats and moved to a safe orbit around the satellite black hole. The worldlet orbited its primary at about the same distance as Earth orbited its sun. And Greyworld lived up to its name, Futurity saw, for its surface was a seamless silver-grey, smooth and unblemished.

To Mara, it seemed, this was home. ‘We live under the roof,’ Mara said. ‘It is held up from the surface by stilts.’

‘We used to call this paraterraforming,’ Poole said. ‘Turning your world into one immense building. Low gravity lets you get away with a lot, doesn’t it?’

‘The roof is perfectly reflective,’ Mara said. ‘We tap the free energy of the Galaxy centre to survive, but none of it reaches our homes untamed.’

‘I should think not,’ Poole said warmly.

‘It is a beautiful place,’ Mara said, smiling. ‘We build our houses tall; some of them float, or hang from the world roof. And you feel safe, safe from the violence of the galactic storms outside. You should see it sometime, Michael Poole.’

Poole raised his eyebrows. ‘But, Mara, your “safe” haven is about as unsafe as it could get, despite the magical roof.’