A wormhole
Farscape-1 navigates a wormhole.
First Used in: 1.01 "Premiere"
Used by: IASA Commander John Crichton, the Ancients.
A Wormhole is a "tunnel" through space-time that results when the spatial dimension of space-time is "torn" allowing one region of space to be matched up with another similar "tear" elsewhere in the universe. It is believed that a wormhole is created when two collapsing stars of the correct size (i.e. proto-black holes) in two distant parts of the universe, collapse without producing a true singularity point (i.e. a true black hole from which nothing escapes.) They can be used to traverse vast distances in a short amount of time.
It was a wormhole that catapulted IASA Commander John Crichton to a distant part of the universe. Crichton seems to have inadvertently brought about the conditions to artificially stimulate the appearance of an unstable version this spatial phenomenon. This happened when Crichton was attempting a "slingshot maneuver" in the Earth's atmosphere in his experimental craft Farscape-1 during a chance solar flare. ("Premiere") The circumstances that led to the creation of this wormhole were never successfully recreated, and it is still unclear what infinitesimal variables led to this event, though similar circumstances were tested at the planet Dam-Ba-Da. They were not exact, however, and resulted in an unstable wormhole. ("Till the Blood Runs Clear")
The Ancients mastered this technology and eventually used it to leave the known Universe. However, before leaving they left a contingent of their species to pass their wormhole technology to a worthy entity. ("A Human Reaction") Such technology was however, too dangerous to be disclosed outright. The Ancients buried the knowledge of wormholes within the brain of John Crichton until such time that he should unravel it on his own.
While this knowledge held the key to John's return to Earth, much peril accompanied any who might use its power. This knowledge also had more unsettling applications. The primary application sought by Scorpius and subsequently the Peacekeeper High Command and Scarran Hierarchy was the ability to use wormholes as an offensive weapon, with the capacity to destroy a ship, an entire planet, or an entire star system. ("Infinite Possibilities - Icarus Abides", "Fractures") Secondarily, there is the problematic nature of wormhole travel. While not only linking distant points in the spatial dimension, it also has the capacity to link points along the dimension of time, allowing individuals to alter the course of history. ("...Different Destinations", "Unrealized Reality") On this same line of reasoning, a wormhole can connect to points in space and time within different dimensions, whether those of extraspatial dimensions otherwise unknown ("Unrealized Reality") or parallel universes with their own histories and timelines. ("Kansas") The wormhole traveller could accidentally return to a time before he left "fracturing" reality and creating another independent time stream. This, however, can be mended if the traveller can return to the wormhole before much damage occurs. ("Unrealized Reality", "Kansas")
The fluid, dangerous nature of the wormhole's "space" means that few craft are actually capable of safely navigating through them. The most prominent craft with the capability is Crichton's Farscape-1. All attempts by the Peacekeepers to send Prowlers through wormholes have uniformly resulted in the pilots being turned into liquid.
The devastatingly sublime power of wormhole technology was realized by John in a "demonstration" before the combined Peacekeeper and Scarran fleets. Crichton demonstrated why the awesome power of wormholes was not to be trifled with. His creation of a self-sustaining wormhole capable of swallowing the entire galaxy forced the realization that the technology to use wormhole technology as a weapon was beyond the control of any lifeform. Using this power as a trump card John forced a multilateral peace treaty between the Peacekeepers and Scarrans. (Farscape: The Peacekeeper Wars)