The gluing abilities of the neutrons were limited. It was once believed that no nucleus could exist with more than a hundred or so protons. But some theorists had predicted that there could be much larger nuclear configurations, with certain special geometries - and these were eventually discovered. The lightest of the superheavy nuclei had a hundred and fourteen protons and a hundred and eighty-four neutrons; the most common appeared to be an isotope called marsdenium- 440, with a hundred and eighty-four protons and a crowd of two hundred and fifty-six neutrons. But there were much heavier nuclei still, with many hundreds of protons and neutrons. These strange nuclei were deformed, squashed into ellipsoids or even hollowed out . . .

She put down her data slate. She found it hard to concentrate on such useless abstractions as this corner of physics - and she didn’t understand how this could have absorbed Symat so much. She did wonder absently why ‘marsdenium’ had that particular name: perhaps ‘Marsden’ or ‘Marsdeni’ was the name of its discoverer. Such historical details were long lost, of course.

As the flitter neared the top of its suborbital hop the curving Earth opened up around her, a rust-red land that glimmered with glassy scars - said to be the marks of humanity’s last war against the Qax, but perhaps they were merely the sites of deleted Conurbations. A Spline craft toiled far beneath her, a great blister of flesh and metal ploughing open a swathe of land, making its own patient, devastating contribution to the Extirpation.

Her flitter drifted to the ground, a few hundred metres from Symat Suvan’s exotic matter plant. She emerged, blinking, beneath a tall sky. Far from the rounded chambers of the Conurbation, she felt small, frail, exposed.

This was a place called Mell Born. It had been spared the starbreaker ploughs so far, but even so nothing remained of the land’s pre-Occupation human usage save a faint rectangular gridwork of foundations and rubble. The place was dominated by a single structure, a giant blue-glowing torus: a facility built and abandoned by the Qax. Now it was occupied by a handful of ragamuffins who called themselves scientists - there were no scientists in the Conurbations. The humans had even built themselves a shanty town, an odd encrustation around the huge Qax facility.

Symat Suvan was here to meet her. He was tall, gaunt, looming, agitated, his eyes hollow; his bare scalp was tanned a pale pink by the unfiltered sun. ‘Lethe,’ he snapped. ‘You.’

She was dismayed by his hostility. ‘Symat, I’m here to help you.’