A Force Rift was a tear in the Force. The Force bound the galaxy together but occasionally it drifted apart in places. That was where a rift appeared. A Force Rift was a hole that was beyond time and space. If someone went into a Force Rift, they could have seen people who have been dead. In a rift, people who had previously existed are incarnated. Even the younger forms of people who were still alive were incarnated there. If someone crossed the rift they may find themselves in any time, place or galaxy.