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 agent s 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 Suliban Cabal ' s mysterious benefactor attempting to sabotage ' s mission , the Sphere - Builder s attempting to manipulate the Xindi into destroying Earth , and Vosk collaborating with the Nazi s 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 : 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 . ( ) 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 Iconian s . 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 - Builder s .