Stargate

A Stargate is an Einstein–Rosen bridge portal device within the Stargate fictional universe that allows practical, rapid travel between two distant locations. The devices allowed its characters to visit alien planets without the need for spaceships or any other type of technology. The device allows for near-instantaneous travel across both interstellar and extragalactic distances, which is faster than light by many orders of magnitude.

They are constructed as hyper-advanced large rings capable of harnessing any source of energy and applying it to maintain artificial stable Einstein–Rosen bridges for the purpose of interplanetary and intergalactic travel, allowing the one-way travel of matter and energy (radio transmissions can travel either way through an open wormhole).

A stargate's destination is not fixed, but is singled out by a process known as "dialing". Once a three-dimensional destination is selected by the traveler, the Stargate generates a stable wormhole between itself and a complementary device at the destination, by being supplied with a threshold amount of raw energy. Objects in transit between gates are broken down into their individual elemental components, and then into energy as they pass through the event horizon, and then travel through a wormhole before being reconstructed on the other side.