Holodeck

Holodeck
A holodeck on the Enterprise-D; the arch and exit are prominent.
Plot element from the Star Trek franchise
First appearance	Star Trek: The Animated Series "The Practical Joker"
Created by	Gene Roddenberry
Genre	Science fiction
In-story information
Type	Simulated reality facility
Function	Creates artificial environments for recreational or training purposes

The holodeck, and "holographic" technology in general, is a plot device used in stories set within the Star Trek universe. It is used to permit stories with locations and characters that could not otherwise exist in the Star Trek setting, and as a means to explore metaphysical and ethical questions.

Although Star Trek's conception of holographic technology is fictional, some scientists have predicted that virtual reality tools similar to the holodeck (but without the ability to touch) "will become a consumer-ready product by 2024."

The holodeck is depicted as an enclosed room in which objects and people are simulated by a combination of transported matter, replicated matter, tractor beams, and shaped force fields onto which holographic images are projected.

Most holodeck programs shown in the episodes run in first person "subjective mode", in which the user actively interacts with the program and its characters. The user may also employ third-person "objective mode", in which he or she is "apart" from the actual running of the program and does not interact with it (all of the program's characters will ignore the user as if he or she was not there (this was shown in the Enterprise episode "These Are the Voyages...").

Matter created on the holodeck ("holomatter") requires the holoemitters to remain stable and will quickly disintegrate if it is removed from the holodeck without a mobile emitter to sustain it, although this principle has been overlooked in some episodes. Writer Phil Farrand has often pointed out how in many episodes matter from the holodeck that gets on a real person still exists when the real person exits the holodeck. In "Encounter at Farpoint", Wesley Crusher falls into a holodeck stream, but is still wet after exiting the holodeck. In "The Big Goodbye", Picard has lipstick on his cheek after encountering a holodeck simulation of a 20th-century woman. In "Elementary, Dear Data", Data and Geordi La Forge exit the holodeck with a piece of paper that originated in the holodeck. This could be explained using replicated rather than holographic matter.