Schild'S Ladder

CASS HAS STUMBLED ON AN ENTIRELY DIFEERENT KIND OF PHYSICS, AND SHE HAS TRAVELLED TO A REMOTE EXPERIMENTAL FACILITY IN THE HOPE OF BRINGING THIS TANTALISING ALTERNATIVE TO LIFE. Cass's experiment is wildly successful: the novo-vacuum is more stable than the ordinary vacuum around it, and a region in which the new physics holds sway proceeds to expand at half the speed of light. Six hundred years later, more than two thousand inhabited systems have been lost to the novo-vacuum. People have come from throughout inhabited space: most are Preservationists, hunting for a way to stop the novo-vacuum before all inhabited space is consumed, but a few believe that the challenge of adapting to survive on the far side of the border would reinvigorate a civilization that has grown stale and insular...