Glossary
Tangent Universe
An unstable copy of reality that branches off the Primary Universe when the Fourth Dimension is corrupted. It survives for a few weeks and then collapses into a black hole unless the Artifact is returned.
The Tangent Universe is the world of the film. It begins on the night of October 2, 1988, when the jet engine (the Artifact) appears in Donnie's bedroom, and it lasts exactly 28 days, 6 hours, 42 minutes and 12 seconds.
Inside a Tangent Universe, the people nearest the Vortex become the Manipulated, the Living Receiver gains Fourth Dimensional Powers, and anyone who dies becomes one of the Manipulated Dead. When the Artifact is sent back through the Time Portal, the Tangent Universe is erased and the Primary Universe resumes at the moment of the rupture.
Defined in The Philosophy of Time Travel