(covers information from several alternate timelines)
Component 37329 was the temporal designation for a rogue comet discovered by the USS Voyager during their journey in the Delta Quadrant.
In an alternate 2374, Chakotay discovered on Annorax's Krenim weapon ship that eight months earlier, component 37329 caused Voyager to set a course so the ship would avoid it completely, which led to them entering Krenim space. Chakotay suggested that Annorax remove the comet from the timeline, so Voyager would not encounter the Krenim Imperium and be severely damaged by their ships.
However, upon running a simulation, it was discovered that removing component 37329 from time would result in the removal of 8,000 civilizations, all life in an area of fifty light years.
This was because four billion years earlier, fragments of the comet impacted a planet, and hydrocarbons from those fragments gave rise to several species of plant life, which in turn sustained more complex organisms, and eventually several space-faring civilizations which colonized the entire sector. (VOY: "Year of Hell, Part II")