Hyperspace

During the period known as the High Republic Era, complete comprehension of hyperspace eluded even the most knowledgeable individuals within the galaxy. Even into the Imperial Era, it persisted as a realm of mystery. Regardless, it existed as a dimension of space-time distinct from that of realspace. Within hyperspace, conventional laws governing space and time were suspended, leading travelers to sometimes employ stasis fields to decelerate the passage of time aboard their vessels, ensuring the pilot's aging remained in sync with the rest of the galaxy.

Entry into hyperspace necessitated molecular displacement, an effect achieved by surpassing the speed of light. This process generated a simu-tunnel, effectively a pocket of realspace, facilitating secure passage through this alternate dimension. The Loth-wolves encountered by the Spectres in 1 BBY possessed a similar capability, traversing at lightspeed via hyperspace tunneling. Hyperspace shared boundaries with realspace, meaning that each point in realspace had a corresponding point in hyperspace, and adjacent points in realspace remained adjacent in hyperspace. Furthermore, every object in realspace—including stars, planets, and asteroids—possessed a "shadow" counterpart within hyperspace. Beyond these established principles, universally acknowledged by competent astrophysicists and astrogation specialists, much about hyperspace remained shrouded in enigma.

Hyperdrives manipulated hypermatter particles to propel a starship into hyperspace, while preserving its mass/energy signature. This dramatically reduced travel distances, enabling vessels to "jump" from one location to another without traversing the intervening space, significantly shortening journey durations. A vessel's capacity to navigate hyperspace hinged on its hyperdrive engine; consequently, ships experiencing hyperdrive malfunctions while in hyperspace, or lacking a hyperdrive and detaching from a vessel equipped with one, would immediately revert to realspace. Cutting power to a functioning hyperdrive would produce the same outcome.

Even seasoned pilots could find rapid hyperspace jumps disorienting, though those with adequate endurance and training could overcome this. Hyperspace whiplash was a condition that afflicted some travelers upon exiting hyperspace.

Due to the "mass shadows" cast by large objects in realspace within hyperspace, hyperjumps demanded meticulous calculations. Without these, a vessel risked colliding with a star or other celestial body. This hazard led to the establishment of designated hyperspace routes for interstellar travelers. Discovering a new, secure hyperspace route could prove decisive in warfare, granting naval forces enhanced mobility, unbeknownst to their enemies. The Galactic Empire deployed Interdictor vessels equipped with gravity well projectors to generate artificial mass shadows, both to extract ships from hyperspace and to prevent them from entering it.

Upon entering hyperspace, a ship appeared to accelerate rapidly—a phenomenon termed pseudomotion—and emitted Cronau radiation, enabling detection of its jump by specialized sensors. Hyperspace could be navigated using various methods, including navigation computers, Force-sensitive navigators, or jump-by-jump journeys. The Unknown Regions featured unstable hyperspace pathways, compelling inhabitants to rely on navigators and jump-by-jump navigation over navicomputers.

Initiating a hyperspace jump from a standstill while docked or exiting hyperspace directly into a planet's atmosphere were generally regarded as impossible feats, even for skilled pilots. Nevertheless, Han Solo accomplished both aboard the Millennium Falcon amidst the First Order–Resistance conflict. Starships typically had safety protocols preventing hyperdrive activation within a planet's gravitational field. Disabling these protocols was perilous, carrying a substantial risk of explosion, severe damage, or disintegration within hyperspace. However, successful jumps near planets were possible: during the Clone Wars, a cruiser transporting an injured Anakin Skywalker experienced accidental hyperdrive activation while still within a planet's atmosphere due to damage from droid fighters, yet it successfully jumped to hyperspace without destruction. Jyn Erso and her companions jumped into hyperspace from within the atmosphere of Jedha after the Death Star destroyed the moon's Holy city. While escaping Lothal in a U-wing, Hera Syndulla jumped to hyperspace directly in front of an Imperial construction module, successfully navigating through its hangar and executing the jump. In a desperate attempt to save the remaining Resistance escape ships, Vice Admiral Amilyn Holdo engaged the hyperdrive of the Resistance cruiser Raddus directly into the path of the First Order Mega-class Star Dreadnought, the Supremacy, inflicting severe damage and obliterating her ship. This maneuver became known as the Holdo maneuver.

The ability to traverse hyperspace existed naturally. The space-dwelling species referred to as the purrgil possessed an innate capability for hyperspace travel. Sometime in the distant past of the galaxy, an ancestral race unlocked the secrets of hyperspace travel, opening the galaxy for exploration. Legend holds that the Rakatans, an ancient amphibious humanoid species originating from the planet Lehon, were the pioneers of hyperspace travel.

Hyperspace travel was mastered as early as four millennia prior to the Cold War, as evidenced by the existence of hyperspace sextants dating back to that era. In the early years of the Galactic Republic, navigating hyperspace between the Greater Seswenna and the Core Worlds required astrogation using hyperspace beacons, necessitating frequent returns to realspace to ensure safe passage. Nonetheless, access to hyperspace travel proved essential to the Republic's expansion, ushering in the era known as the Great Hyperspace Rush.

Approximately two centuries before the Invasion of Naboo, starships across the galaxy were abruptly forced out of hyperspace during the Great Hyperspace Disaster, orchestrated by the Nihil. Utilizing their path engines, the Nihil were able to achieve feats with lightspeed previously considered impossible. Generalirius Nakirre of the Kilji Illumine nation regarded hyperspace as a chaotic swirl.

During the First Order–Resistance conflict, the First Order discovered sub-hyperspace, which they employed with their superweapon, Starkiller Base. The firing of Starkiller Base during the Hosnian Cataclysm in 34 ABY released sufficient energy to create a transient tear in sub-hyperspace. This event made the disaster visible across the galaxy instantaneously, albeit briefly.