Cassius Project: this is a Dyson sphere in the process of construction, an object first described in 1959 by the physicist Freeman Dyson in his paper ‘Search for Artificial Stellar Sources of lnfra-Red Radiation’, though the idea germinated in him after reading a science fiction story by one Olaf Stapleton some thirteen years earlier. It is a hollow sphere being built around the sun, Cassius, to capture nearly all the star’s radiation so as to power (at nearly 1026 W) the civilization that will occupy the inner surface of the sphere when the project reaches completion. Construction began in that hugely optimistic time during the initial runcible-based expansion of the Polity, when it was felt that anything could be achieved. The project stalled during the Prador-Human War, but then continued after because, some claim, it was felt by the AIs that a sense of optimism needed to be reclaimed for the human race. It has caused much contention in the Polity because, with its completion date lying in the remote future, it is felt irrelevant to present requirements. However, few can deny the massive technological advances stemming from this project, and the rejuvenating economic effect throughout that sector of the Polity. Perhaps few can also deny that this is forward planning on a truly ambitious scale.

— From ‘Quince Guide’ compiled by humans

Horace Blegg considered the universe as a web of lines interconnecting nodal points which, studied with sufficient intellect, would reveal its holistic nature. How fated is this particular node? He did not personally believe in determinism, but some coincidences seemed almost too coincidental to ignore. He walked out along a gravplated platform to a viewing blister in one half-completed section of the giant ship’s outer skin. To his left he observed the muted glare of ion engines which maintained the vessel’s position in the planet’s shadow. The engines were necessary for correction because the ship’s mass was perpetually changed by materials being brought in through four internal cargo runcibles. Also many smaller vessels docked and undocked all the time, changing its vector. In two days the ship would be completed, and by then, hopefully, it would no longer be necessary to keep it this close to the world in order to relay the thousands of tonnes of equipment coming through the runcibles, and then it could move out into a more comfortable orbit around the sun. Just down to his right he observed the shuttle he had requested, now docking, but there was no hurry.

‘A space tug will arrive in thirty hours,’ said the Golem beside him, which was telefactored from the ship’s newly initiated AI: Hourne—named after one of those who had discovered the nature of the object below, just as the world itself was now called Shayden’s Find, and the sun was called Ulriss.