Holodeck September 21, 1974

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A holodeck is a simulated reality facility located on starships and starbases in the fictional Star Trek universe. The holodeck is depicted as an enclosed room in which objects and people are simulated by a combination of replicated matter, tractor beams, and shaped force fields onto which holographic images are projected. Sounds and smells are simulated by speakers and fragranced fluid atomizers, respectively. The feel of a large environment is simulated by suspending the participants on force fields which move with their feet, keeping them from reaching the walls of the room (a virtual treadmill). Perspective is retained through use of sound damping fields and graviton lenses, which make objects, people, and sounds appear to be more distant. The effect is an ultra-realistic simulation of an environment, with which the user can interact. The first episode featuring a holodeck was "The Practical Joker", a non-canon animated episode in which it was called a "recreation room". Source: [Wikipedia link]