Temporal incursion
Temporal incursion was the term used to refer to an act of altering the timeline. As of the 29th century, there were agencies specifically tasked with protecting the timeline from any changes caused by time travel, such as the Temporal Integrity Commission, and the temporal agents of the 31st century. (; )

The Krenim scientist Annorax used the energy beam of his weapon ship to initiate temporal incursions. ()

The level of alteration to the timeline after incursions was measured by 29th century Starfleet operatives in levels of incursion factors. For example, an incursion factor of 0.0036 was considered only a minor change to the timeline. () The Krenim also probed the continuum after an incursion and calculated the level of temporal restoration in comparison to the original timeline in percentages. ()

Examples

Temporal Cold War
Numerous temporal incursions occurred as part of the Temporal Cold War. Multiple factions, each one vying for control, attempted to change history to suit their own ends. Examples include the 's mysterious benefactor attempting to sabotage 's mission, the Sphere-Builders attempting to manipulate the Xindi into destroying Earth, and Vosk collaborating with the Nazis in 1944. These factions were opposed by Temporal Agents, who represented themselves to the crew of Enterprise in the form of , who would often assist the crew in protecting the timeline. ()

The Borg
In 2373, a Borg sphere traveled back in time to April 4, 2063, in an attempt to prevent Humanity's First Contact with extraterrestrials and assimilate the Human race at a time period in which they were ill-equipped to offer resistance. Arriving in Earth orbit through a temporal vortex, the sphere immediately began firing upon Zefram Cochrane's launch facility in central Montana, but was itself destroyed by the crew of the , who had followed the Borg through the vortex. The crew subsequently assisted Cochrane in making repairs in time for his scheduled launch, ensuring that a Vulcan survey ship detected his warp signature, making First Contact on April 5th. ()

The events of this incursion constituted a Pogo paradox, in which interference to prevent an event actually triggers the same event. It also set into motion a chain of events in which a group of surviving drones were revived in 2153, and subsequently sent a message to the Delta Quadrant, where it was received by the Collective in the 24th century, alerting the Borg as to the location of Earth. (; )

Annorax

Annorax, a Krenim scientist, initiated a multitude of temporal incursions during his quest to restore the Krenim Imperium to power. Using a massive weapon ship to literally erase objects from history, he attempted to manipulate the timeline in order to ensure Krenim superiority. His efforts met with failure, however, when erasing the Rilnar civilization from the timeline had disastrous effects for the Imperium. For over a century, Annorax and his crew attempted to restore the Imperium by erasing ships, colonies, and even entire civilizations from history. In 2374, Annorax was opposed by the crew of the , who were attempting to cross through Krenim space on their journey back to the Alpha Quadrant. Eventually, as a result of massive battle damage, a temporal incursion was initiated within the weapon ship itself, erasing it, and all of the damage it had caused to history, from the timeline. ()

Voyager
During its seven-year voyage through the Delta Quadrant, the starship Voyager was involved in numerous temporal incursions, including those involving the Krenim. Some notable examples include:

Traveling back in time to Earth, 1996, after a confrontation with 29th century Starfleet officer Captain Braxton, in which Braxton described Voyagers involvement with a devastating temporal explosion in the future, ironically caused by Braxton's efforts to prevent it. The future was saved when Voyager destroyed Braxton's temporal ship and was then returned to its correct time by Braxton from the corrected future. ()
A temporal inversion in the Takara sector, wherein Chakotay and Harry Kim successfully changed history, saving Voyager from destruction in 2375. ()
Stopping Captain Braxton from destroying Voyager in 2375 with a temporal disruptor, and initiating a phaser fight with Seven of Nine at Utopia Planitia in 2371. ()
Meeting a future version of Vice Admiral Kathryn Janeway and receiving future technologies and weapons such as the transphasic torpedo and the ablative generator in order to get home via a transwarp hub. This allowed Voyager to get home and destroyed Unimatrix 01 as well as the Borg Queen and the transwarp hub, potentially crippling the Borg. ()

Nero

In the year 2387, when a supernova threatened to destroy the entire galaxy, Ambassador Spock utilized red matter to create a black hole with which to absorb the exploding star. Although Spock's efforts were successful, he was too late to save Romulus, which was destroyed. Nero, captain of the Romulan mining vessel Narada, confronted Spock, holding him responsible for the destruction of his homeworld. During the confrontation, both vessels were pulled into the black hole and transported back through time, the Narada arriving in the year 2233, resulting in the creation of an alternate reality. Upon emerging from the black hole, Nero immediately attacked the , setting into motion a chain of events causing a drastic difference in the histories of the two timelines. Spock, having entered the black hole only moments after the Narada, emerged in the year 2258, and was immediately captured by Nero, who forced Spock to witness the destruction of  at Nero's hands. Eventually, with assistance from Spock,  and  were able to put a stop to Nero's efforts to perform the same action on every Federation world, destroying the Narada with another artificially-created black hole. ()

Following the temporal cold war, the Federation and Starfleet in 3189 was aware of this incursion. They learned about the Narada's incursion from time soldier, Lieutenant Commander Yor. ()

See also
Alternate timeline
Quantum incursion
Temporal violation

Appendices

Background information
In Star Trek Online, an alliance of the Federation, Romulan Republic, Klingon Empire, and various Delta Quadrant powers explored the use of temporal incursions to attempt to stop an invasion by the Iconians. Using a Krenim weapon ship based on Annorax' designs, the alliance attempted a temporal incursion to prevent the rediscovery of Iconia by the , in order to delay the resurgence of the Iconian empire, as well as prevent the supernova that destroyed Romulus. Unfortunately, unforeseen factors in the incursion also cause the Romulan Star Empire to be assimilated by the Borg Collective. The alliance attempted to correct the timeline, though the corrected timeline indirectly caused the creation of the race that would be known as the Sphere-Builders.

External link

de:Temporaler Eingriff
Time travel