The only means of freeing itself from the limits imposed by the speed of the light is to pass in addition to the space-time curve. Being based on the principles of General Relativity, the authors of SF imagine a universe à.quatre.dimensions, infinite but limited, an hypersphere plunged in a hyperspace.
The jump of a spacecraft through the hyperspace consists in exploiting a singularity deforming in a very localised way the curve of the space time and resembling a fold which would put in contact two distant points on the envelope of a balloon.
These singularities can be natural (minis hole-blacks) and more or less permanent: the navigators of space know them in an empirical way, like the sailors of the Rebirth learned howto know the geography of the currents on the surface of the oceans. These singularities can also be caused by the vessel itself, during a very short lapse of time (the energy expenditure is enormous): the spacecraft moves by deforming its environment, by successive crumplings or jumps.
In the "Instrumentality of Mankind" cycle, after having told the pioneering days of the sailors, pilots of solar sailing ships, Cordwainer Smith introduces the discovery of the journey into the hyperspace or planoform flight, with a short story entitled "the Colonel returned from Great Nothing".
In the film Dune of David Lynch, drawn from the famous novel of Frank Herbert, the realizer presents, in a majestic visual sequence, the way in which the Navigators of the Space Guild learned how to fold up space. A fleet of shuttles is fastened inside Long-distance Guild spaceship, orbits about it around the Caladan planet. In the following scene, in orbit around Dune, located at a distance of a hundred light-years of Caladan, the Long-distance spaceship materializes.
The corridors calibans, in Star and the Whip of Frank Herbert also, are tubes which make it possible to connect instantaneously distant points in the universe. It is enough to activate a corridor using a special key so that at once, a vortex is formed, some steps inside the tube, where the air takes a sirupeuse consistency, and one emerges at his point of destination.
The metaphor of the dimensional doors is taken again in a spectacular way in the cycle Cantos d' of Hyperion, written by Dan Simmons, and also in the Stargate film and TV series.
In Hyperion, the Doors connect instantaneously distant points in the universe, which makes it possible to build buildings as strange as multi-planet residences, where the bathroom is located on a marine planet, while the window of the living room opens on the capital of the administrative planet of the Galaxy.
The Caliban corridors in Star and the Whip were offered to humanity by benevolent extraterrestrial beings but their operation remains incomprehensible. In the same way, in Hyperion, the Doors are usually used by humanity but their mechanism is known only from Artificial Intelligences which conceived them. All the balance of human civilization in the Galaxy starts to waver as from the moment when some corridors or some Doors disappear...
Apart from the very particular case of the dimensional doors, the journey through the hyperspace presents specific dangers: In Star Wars, Han Solo warns Luke Skywalker that to the least miscalculation, the Millenium Falcon could leave the hyperspace in the beautiful medium of a star.
In the short story "the Play of the Rat and Dragon", drawn from the cycle "Instrumentality of Mankind" written by Cordwainer Smith, one learns how that the hyperspace is filled with evanescent creatures , avid to absorb the spirits of the travellers. Against these Dragons, telepathic especially involved, called Pare-Light, defend their vessel during the planoform flight while making use of luminous bombs.
The background of the plays of plate of the family Warhammer 40,000 also rests it on a populated hyperspace of hostile demonstrations to the travellers, resulting from the unconscious collective of the intelligent creatures which populate the universe. In fact, the forces of Chaos adored by deviating sects on planets of the Imperium are manifestations of the dangerous powers hidden in the hyperspace.