Manheim effect

The Manheim Effect, named after Dr. Paul Manheim, was a term coined by Lieutenant Commander Data aboard the USS Enterprise-D in 2364, to describe the unusual temporal distortions created by Manheim's experiments into time. Manheim had created the effect when he opened a "window" into another dimension on Vandor IV. The Effect consisted of a moment in time looping, or of people seeing a preview or repeat of the near future or near past. The Effect was felt throughout a radius of a few thousand light years from Vandor, notably on the USS Lalo, Coltar IV, and the Ilecom system. It was stopped when the "window" was sealed by Data. (TNG: "We'll Always Have Paris")

By 2387 the term was more accuratlly defined as an event taking place within non-linear time with many different periods in time (and possibly parallel universes) interacting with each other caused by iso-dimensional temporal disturbances (such as chronometric particle waves). Ria McCarthy identified the merging of two time periods within her quarters as an example of the Manheim effect. (Star Trek: Pioneer: "The World At The Edge Of Time")