The Trialan sun's core periodically built to a cascade effect at the quantum level, causing Meridian to shift from one dimension to another. The planet appeared in regular space every sixty years. When in the other dimension the planet's thirty inhabitants existed as pure consciousness and the planet and everything on it disappeared from normal space. This had been the case for thousands of years prior to 2371.
By 2371, however, the planet had been undergoing changes for several centuries and its time in normal space had been growing shorter with each visit. At that time, Meridian would manifest in normal space for only twelve days, and it was predicted that within a few centuries their stay would last only minutes.
That year, the USS Defiant, on a mission of exploration in the Gamma Quadrant, was present when Meridian returned to normal space for the first time since 2311. The crew of the starship studied the Trialus sun along with the scientists of Meridian and discovered an instability that was causing the shortened stay of the planet in normal space. With the help of the Defiant the inhabitants were able to stabilize the star and expected their next manifestation to last thirty years, long enough to begin having families again. Jadzia Dax attempted to remain on Meridian as it shifted realities, but was unable to as her presence would have destroyed the planet. (DS9: "Meridian")
- See: Meridian inhabitants
According to StarTrek.com, this planet's technical name was Trialus I. The Star Trek Encyclopedia (4th ed., vol. 2, p. 37) classified Meridian as a class M planet. Furthermore, in the note section of the entry, it is noted that "the painted forest backdrop used outside the Meridian hall was rented from Walt Disney Studios, which had originally created the backdrop for the movie Mary Poppins. The Meridian hall itself was also seen (in modified form) as the Klingon Great Hall in "The House of Quark" (DS9), the Albino's lair in "Blood Oath" (DS9), and Masaka's temple in "Masks" (TNG)."