The collapsing empire

Faster than light travel is impossible--until the discovery of The Flow an extradimensional field available at certain points in space-time which can take us to other planets around other stars. Riding The Flow humanity spreads to innumerable other worlds. Earth is forgotten. A new empire arises the Interdependency based on the doctrine that no one human outpost can survive without the others. It's a hedge against interstellar war--and for the empire's rulers a system of control. But when it's discovered that the entire Flow is moving possibly separating all human worlds from one another forever a scientist a starship captain and the emperox of the Interdependency must race to find out what can be salvaged from an empire on the brink of collapse. --