An Omega molecule was a highly unstable molecule believed to be the most powerful substance known to exist. With sufficient amounts of boronite the molecule could be synthesized. However, proper containment methods did not exist to prevent the violent destabilization of the molecule, which destroyed subspace and rendered warp travel impossible.
- Some cosmologists theorized that Omega existed in nature at the instant of the Big Bang, when the universe as we know it was born.
- Presumably, an Omega molecule would be so energetic that a small string would be able to power a whole civilization.
The Borg learned of the substance in 2145 through the assimilation of thirteen species, and were able to synthesize a single molecule of Omega that remained stable for one-trillionth of a nanosecond. The experiments the Borg conducted on Omega destroyed a total of 29 Borg vessels and 600,000 drones. The Borg, who referred to Omega as Particle 010, regarded Omega with near-reverence as they believed it to exist in a flawless state. Because the Borg saw the Omega molecule as "perfection", all Borg were ordered to assimilate it at any cost. From their data, the Borg designed a harmonic resonance chamber that could theoretically stabilize the molecule, but according to Seven of Nine they didn't have enough Boronite Ore to synthesize more Omega molecules.
A single Omega molecule was synthesized in the late 23rd century by the Federation physicist Dr. Ketteract on board a classified research station in the Lantaru sector. The molecule remained stable for a fraction of a second before it exploded, killing 127 leading Federation scientists and consequently destroying subspace throughout the sector through rupturing.
This secondary effect made it impossible to create a stable warp field, complicating rescue efforts. The accident was covered up and the impassibility of the Lantaru sector was explained as a natural phenomenon. Starfleet Command then suppressed all knowledge of Omega, and enacted the Omega Directive on which only starship captains and flag officers were briefed.
"Omega destroys subspace, a chain reaction involving a handful of molecules could devastate subspace throughout an entire quadrant. If that were to happen, warp travel would become impossible. Spacefaring civilization as we know it would cease to exist."
Another civilization in the Delta Quadrant was actually successful in synthesizing some 200 million Omega molecules in 2374. They were able to keep the molecules stable by using Omega's own resonance frequency (1.68 terahertz) to calibrate their containment-field, though eventually an accident devastated their research facility. The starship USS Voyager managed to neutralize the molecules before they could do any further damage to subspace. Seven of Nine adapted the Borg harmonic resonance chamber design, to emit an inverse frequency which would dissolve Omega's interatomic bonds. Seconds before the harmonic resonance chamber was jettisoned into space, the molecules started to stabilize spontaneously, and remained stable for at least 3.2 seconds. The remaining Omega molecules were destroyed by a modified gravimetric torpedo.
In the game Star Trek: Armada, the Borg, led by a clone of Locutus of Borg, led an unsuccessful attack in 2376 upon the Federation and the Klingon and Romulan Empires in an attempt to gain an Omega particle, before being destroyed by the USS Enterprise-E.
In the game Star Trek Online, in a rare star cluster exploration mission, Starfleet command orders the player's ship to scan a star system for Omega molecules and destroy them. In the end of the mission, the player finds out that there were no Omega molecules in the system and the mission is completed. In the mission "Skirmish", the player is asked to scan a ship for abnormalities. One option is to scan for Omega molecules. After trying this scan (which results negative), the player's science officer says, "Captain, what are Omega molecules?". In the recent Season 8 update, "The Sphere", players enter a Dyson sphere to secure a mysterious factory constantly producing Omega molecules from the Voth, who believe it's their right to have the molecules as dictated by their Doctrine.
In Star Trek: Legacy, the Ketteract incident is found to have been orchestrated by the assimilated Vulcan T'Urell, who actually stabilized the Omega Particle and used it to power a sphere that was destroyed by James T. Kirk. leading to the particle's destabilization. In this interpretation of the Ketteract Incident, Kirk recommended the establishment of the Omega Directive. Legacy depicts a stabilized particle while VOY: "The Omega Directive" mentions that the particle was destabilized fractions of a second after creation – it is possible that even starship captains were only told that the particle exploded upon being created as a cover story to prevent possible classified information about T'Urell from being disseminated.
The Star Trek: Section 31 book Cloak provides a different portrayal of Ketteract's experiment. In the novel, Section 31 actively participated in the disastrous Omega experiment in the 23rd century. The crew of the original USS Enterprise barely escaped when the molecule destabilized.
The Borg fascination with Omega is described in the Star Trek: Destiny novel trilogy. The race the Borg descended from (the Caeliar) utilized it as a power source. Following the degradation of a Caeliar group exiled due to an accident, their connection to Omega (and a power source for their nanoprobes called catoms) was lost. This led the first Borg Queen to focus on recovery of Omega; however, they lost their knowledge of how to control the particles or synthesize them.
In The Eternal Tide, Voyager learns that the Omega molecule did indeed trigger the Big Bang, and is increasingly building power and stability in a sub-dimension, essentially 'counting down' to the end of this universe. When a civilian scientist expedition encountered a rift into this dimension, they unintentionally accelerated this decay as their matter provided Omega with additional energy, but the instability caused by this chain reaction also created the Q Continuum, the Q serving as a creative force to 'counter' the destructive potential of the Omega Continuum. Although Q believes that the only way to stop the decay would be to reverse the original incident and thus essentially erase the Q Continuum from existence, Voyager is able to repair the disruption while only shortening the universe's lifespan by a few million years as opposed to the trillions they would have lost previously, thus saving the Q, but this is only achieved through the sacrifice of Captain Afsarah Eden- a 'child' of the Omega Continuum created when the continuum manifested a new entity based on a scientist who discovered it and Q's son, who possessed the potential to channel the power of Omega and contain it once again.
In the canceled Star Trek: Borg Assimilator game, the main goal is to develop a stable Omega particle, and then go on and assimilate the Alpha Quadrant.
In the backstory for the proposed and abandoned animated series Star Trek: Final Frontier, the galaxy would have been devastated by a series of Omega particle detonations, making large areas impassable by warp drive.