Portal (doorway)

The word "portal" in science fiction and fantasy generally refers to a technological or magical doorway that connects two distant locations separated by spacetime. It usually consists of two or more gateways, with an object entering one gateway leaving via the other instantaneously.

Places linked by a portal include a different spot in the same universe (in which case it might be an alternative for teleportation); a parallel world (inter-dimensional portal); the past or the future (time portal); and other planes of existence, such as heaven, hell or other afterworlds. A parallel world, such as C. S. Lewis's Wood between the Worlds in his Chronicles of Narnia, may exist solely to contain multiple portals, perhaps to every parallel world in existence.

Portals are similar to the cosmological concept of a wormhole, and some portals work using wormholes.

Portals are often used in science fiction to move protagonists into new territory. In video games the concept is often used to allow the player to cover territory that has already been explored very quickly. A related book plot that is commonly used is the struggle to get to the opposite end of a new gate for the first time, before it can be used.

In film and television, a portal is often portrayed using a ripple effect.

Other examples of portals include:

In his Hyperion Cantos novel series, Dan Simmons imagines a network of portals called "farcasters" which connect most human-inhabited planets. The form these portals take can vary, and they may be opaque, completely transparent, or semi-transparent. The completely transparent variety is very commonly used and effectively turns all connected places into one giant WorldWeb where distance becomes almost meaningless. Some of the more opulent occupants may have houses where each room is built on a different planet, and some rooms themselves may be partially built in several different physical locations but be joined by farcaster portals to form one complete room.

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