A temporal rift is a tear in spacetime and an extremely dangerous temporal anomaly. Encounters with temporal rifts usually end with the vessel making contact with the rift being transported to a different time and space.
The USS Bozeman encountered a rift which exploring the Typhon Expanse. The rift sent the ship ninety years into the future, to the year 2368. The Bozeman exited the rift on a collision course with the USS Enterprise-D, which caused a temporal causality loop when they collided. (TNG: "Cause and Effect")
The USS Intrepid, under the command of Luciano Mantovanni, fell through a temporal rift, re-emerging in 2368. (Star Trek: Liberty)
29th century Starfleet vessels could travel through time by creating artificial temporal rifts. One such ship, the Aeon did this to travel to 2373 in an attempt to destroy the USS Voyager. The rift destabilised, sending both Voyager and the Aeon back to the 20th century. (VOY: "Future's End", "Future's End, Part II")
Also in 2373, an away team from the USS Cantabrian, aboard a shuttlecraft, was hit by a temporal displacement wave (which, in turn, created a temporal rift), travelling back in time. After gaining assistance from the USS Cantabrian's captain Thekla Lawless, the team found the temporal wave and returned to their own time. (Star Trek: The Cantabrian Expeditions: "The Fire In Which We Burn")
In an alternate timeline's year 2404, Admiral Kathryn Janeway created a temporal rift to travel back in time to help the Voyager return home 16 years earlier than in her timeline. The plan worked, with Voyager returning from the Delta Quadrant in 2378 instead of 2394 in the original timeline. (VOY: "Endgame")
Narendra temporal rift[]
In 2366, the Enterprise-D encountered a temporal rift near Narendra III. Sensors indicated an emerging vessel, but the readings vanished and the phenomenon collapsed shortly thereafter.
- In fact, the rift was created by a battle between the Romulans and the USS Enterprise-C in 2344 at the Narendra system. The Enterprise-C emerged from the rift, creating an alternate timeline in which the Federation and Klingons were still at war. The rift was collapsed by sending the Enterprise-C back through, restoring the timeline. (TNG: "Yesterday's Enterprise")
Lieutenant Kayl and a sedentary-Captain Daniel came through the temporal rift during the Romulan-Enterprise-C battle in 2344, from the year 2379, and crashed onto Narendra III, where Kayl decided to live in seclusion. (Star Trek: Phoenix-X: "Occurrence, Part I & II")
In 2375, Commander Seifer re-activated the temporal rift near Narendra III by flooding it with tachyons. The resulting action sent his ship back in time to 2367. There he revived Daniel and both displaced officers spent two years on a mission overseeing a transwarp project. In 2369, they returned using the USS Phoenix-W, which upon exiting a transwarp conduit, exploded near the Narendra III temporal rift. The explosion re-activated it long enough to allow Commander Seifer to travel to the future using the Phoenix-X's Vector 3. (Star Trek: Phoenix-X: "Secret Occurrences")
Gordan's vessel was destroyed in 2379, after attempting to manipulate the temporal rift near Narendra III. Kayl and a sedentary-Captain Daniel were sent back in time though it, to the year 2344. (Star Trek: Phoenix-X: "Occurrence, Part II")
External link[]
Temporal rift article at Memory Alpha, the canon Star Trek wiki.