The universe, also known as the cosmos, is all matter, energy, and space regarded as a whole, is filled with clusters of stars known as galaxies which are grouped by gravity. The laws of the universe are governed by time. It is one of several elements of the multiverse, thus causing it often to be referred as the prime universe in reference to other realities.
In 2257, the Philippa Georgiou from the mirror universe referred to her deceased counterpart in the universe she had come to inhabit by saying "You have obviously confused me with my sentimental prime universe counterpart." (DIS: "Perpetual Infinity")
All the matter of our universe originated from the parallel Megan universe through creation points. Creation points were the active portals between the two-dimensional planes. In the Megan universe, magic, the ability to control reality with thoughts, was part of the natural laws. (TAS: "The Magicks of Megas-Tu")
The universe was formed in the instantaneous expansion that scientists call the Big Bang. The Big Bang has been theorized to be caused by destabilizing Omega molecules. (VOY: "Death Wish", "The Omega Directive") According to an engineer on board the USS Voyager, the universe was sixteen billion years old. (VOY: "Good Shepherd")
According to Jack, our universe will collapse in on itself sometime between the next sixty to seventy trillion years. The universe contains too much matter to keep expanding. According to Jack, a massive spherical grid of subspace field generators could be used to manipulate subspace to reduce the mass of the universe and change the cosmological constant. This would avert the collapse. (DS9: "Chrysalis")
Our universe contains several parallel time continuums occupying the same space but in a different time. (TNG: "Time's Arrow", "Timescape") The Devidians, for example, lived in a different time continuum that was only a fraction of a second away but with a positive phase variance of 0.004 percent from normal time. (TNG: "Time's Arrow", "Time's Arrow, Part II")
Our universe is only one of several types of parallel universes. A new universe can be shaped by a person's thoughts while inside a warp bubble. While Dr. Crusher was caught in a shrinking warp bubble and asked the computer for the definition of the universe, it replied: "The universe is a spheroid region seven hundred and five meters in diameter." A scan of the edge of that universe revealed it to be a mass-energy field. (TNG: "Remember Me")
End of the universe Edit
In 2364, the Traveler inadvertently took the USS Enterprise-D to a location over one billion light years from the Milky Way Galaxy, where thoughts were the essence of reality. It was believed that the place was the outer rim of the universe, where the universe ends. An illusion of Yvette Gessard-Picard said it was actually the beginning of the universe and not the end. The Traveler said Humans would naturally have reached this area in the far distant future when they learned to control their thoughts. The thoughts, imagination and memories of the crew began to manifest as subjective or shared reality. In this unknown region, visually unidentified objects of huge size, resembling transparent cubes with bright glowing corners, sped past the ship in groups with seemingly random patterns, in a blue nebulous background. (TNG: "Where No One Has Gone Before")
Related to this event, the euphemisms "end of the universe", "where none has gone before", and the "outer rim" were informally used by Captain Jean-Luc Picard of the Enterprise-D to describe this unknown area. As of the late 24th century, it stood as the furthest location in the universe reached by the Federation. (TNG: "Where No One Has Gone Before") Lieutenant Commander Dexter Remmick called the location the "edge of the universe". (TNG: "Coming of Age")
- Parallel universe
- Space-time continuum
Background information Edit
Memory Alpha uses the terms "prime timeline", "prime reality", and "prime universe" to describe the main or original timeline of events in the universe depicted in the various Star Trek episodes and movies prior to the 2009 movie Star Trek, in which an alternate reality was created. The term "prime" is derived from the film's credits, where the character played by Leonard Nimoy was disambiguated from Zachary Quinto's Spock as "Spock Prime". Roberto Orci said about the alternate timeline that they "think of it is [sic] as identical to the original until Nero arrives." 
This terminology made its in-universe debut in DIS: "Perpetual Infinity", where mirror Georgiou refers to the primary universe as prime universe, the exact phrase being "You have obviously confused me with my sentimental prime universe counterpart."