Gravity-quake

A gravity-quake was a natural disaster which could occur when two star systems came two close together, and the conflicting gravities of each system's suns destabilised the orbits of the systems' planets.

When Don Arco told the Ninth Doctor that he planned to transport the Justicia system through space via a warp-hole, the Doctor told him that this was dangerous and would likely create a gravity-quake. (PROSE: The Monsters Inside)