Dark matter
Dark matter is a substance which was undetectable via the use of normal sensors, and which was thought to make up the majority of the universe's mass.

Extremely exotic, dark matter can take a number of forms, such as nebulae, asteroids, and even lifeforms. It could also be weaponized. (; ; )

Dark matter nebulae

By the year 2153, Vulcan scientists had successfully excited small amounts of dark matter via bombardment with metreon particles. In that year, Starfleet officer Jonathan Archer, captain of , and his first officer, Sub-Commander T'Pol, expanded upon these experiments and successfully illuminated a dark matter nebula by utilizing specially-modified spatial charges to distribute the particles over a larger area. ()

In 2367, the crew of the  conducted experiments to study the Mar Oscura, a previously-unexplored dark matter nebula, illuminating it with specially-modified photon torpedoes. During their investigation, the Enterprise crew discovered that, due to the unusual preponderance of dark matter in the nebula, small gaps had formed in the fabric of normal space, causing parts of the ship to momentarily phase out of normal space during a collision with one of these deformations. Eventually, by piloting a shuttlecraft ahead of the ship, Captain Picard was able to successfully navigate the Enterprise safely out of the nebula. ()

In 2371, Commanders Chakotay and Tuvok of the  encountered a dark matter nebula while on board a shuttle, subsequently coming under attack by a species known as the Komar, a non-corporeal race who were able to take over Tuvok's body. Rendezvousing with Voyager, the Komar, posing as Tuvok, attempted to deceive the crew into returning to the nebula, where the rest of his people were planning on extracting the crew's neural energy for sustenance. Fortunately, Chakotay, whose own neural energy had been displaced, was able to inhabit various members of the crew and sabotage the Komar's plans and lead Voyager out of the nebula. ()

In 2372, Neelix related a story to Ensign Kim and Lieutenant Paris of a time when he lost a nacelle while traversing a dark matter nebula. As related by Neelix, as he traveled through the nebula, dark matter bow waves were created, eventually building up so much pressure as to cause catastrophic damage to his ship. This story provided the inspiration to Paris and Kim needed to solve a depolarization problem impeding their success on the creation of a transwarp drive. ()

In 2374, while engaged in combat with the Jem'Hadar, Benjamin Sisko ordered his ship, an appropriated Jem'Hadar fighter, into an uncharted dark matter nebula in an attempt to evade their pursuers, eventually crashing on a planet within the nebula. ()

Dark matter asteroid
In 2257 the crew of Discovery encountered a dark matter asteroid while investigating a red burst in interstellar space.  Subsequent study revealed the asteroid contained metreon particles.  A piece of the asteroid was later used to save the inhabitants of Terralysium. ()

In 2376, the crew of Voyager encountered a dark matter asteroid while tracking a graviton ellipse. As the ellipse had been changing course, apparently randomly, and the crew became aware that it was attracted to electromagnetic energy, Captain Janeway ordered the sensor arrays realigned to scan for EM fluctuations, and discovered the asteroid, drawing the ellipse toward a collision. ()

Dark matter lifeforms

In 2376, while on an excursion in the , Captain Janeway and members of her crew encountered a phenomenon which neutralized ninety percent of their antimatter and damaged the hull of the ship. One of the crew, Mortimer Harren, stated his belief that they had encountered a dark matter proto-comet, a phenomenon the existence of which he had hypothesized. It was later discovered, however, that what they had encountered was, in actuality, a dark matter lifeform, despite Harren's insistence that molecules so complex would collapse under their own weight. One of these lifeforms was able to successfully take over the body of William Telfer, another member of the crew, and attempt communication. Upon leaving Telfer's body, the lifeform was killed by Harren who, in a moment of panic, destroyed it with a hand phaser. The lifeforms subsequently attacked the Delta Flyer in retaliation, although Janeway and her crew were able to escape by using the Flyers phasers to set off a chain reaction in the radiogenic rings of a planet, where they were attempting to reinitialize their warp reaction. ()

See also
 Dark energy
 Dark Matter Anomaly

External link 
 

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Physics