Xeelee Sequence

A spaceship from Earth accidentally crossed through a hole in space-time to a universe where the force of gravity is one billion times as strong as the gravity we know. Somehow the crew survived, aided by the fact that they emerged into a cloud of gas surrounding a black hole, which provided a breathable atmosphere. Five hundred years later, their descendants still struggle for existence, divided into two main groups. The Miners live on the Belt, a ramshackle ring of dwellings orbiting the core of a dead star, which they excavate for raw materials.  

Half a million years in the future, on a dead, war-ravaged world at the centre of the galaxy, there is a mile-high statue of Michael Poole. Poole, born on Earth in the fourth millennium, was one of mankind's most influential heroes. He was not a warrior, not an emperor. He was an engineer, a builder of wormhole transit systems. But Poole's work would ultimately lead to a vast and destructive conflict, a million-year war between humanity and the enigmatic, powerful aliens known as the Xeelee. The Xeelee won.

Michael Poole finds himself in a very strange landscape.... This is the centre of the Galaxy. And in a history without war with the humans, the Xeelee have had time to built an immense structure here. The Xeelee Belt has a radius 10,000 times Earth's orbital distance. It is a light-year in circumference. If it was set in the solar system, it would be out in the Oort Cloud, among the comets - but circling the sun. If it was at rest, it would have a surface area equivalent to about 30 billion Earths. But it is not at rest: it rotates at near light speed.