Hyperspace is the state of existence used by star-ships to achieve faster than light (FTL) travel. It is a phenomenon not completely understood by scientists; it is alternately described as a parallel universe, an extra 'dimension' of space and time, and an alternate mode of physical existence.
Normal baryonic matter obeys physical principles of relativity; they increase exponentially in mass as they approach the speed of light, requiring more and more energy to approach it, and thus must always remain below this threshold. Tachyonic matter, on the other hand, exists solely above the speed of light, and cannot pass below. Hyperdrive technology breaks this barrier and allows slower-than-light starships to leap past the barrier and reach speeds many thousands or millions of times that of light.
This principle was first discovered by the ancient Rakata, whose Force-enabled drives allowed them to create a galaxy-spanning empire. Some of the earliest hyperspace-utilizing artifacts, such as strange arches and matter transmitters found on ruined worlds, cannot be replicated by modern hyperdrive technology. Corellians and Duros were the earliest able to create technological versions of the Force-enhanced Rakatan devices, and build the first true hyperdrives. Consequently, despite common usage, relatively little is known about the true nature of hyperspace. Does it utilize another dimension to 'sidestep' the light barrier? Does it phase matter directly into another universe, similar to Otherspace or subspace, to gain supralight speeds? Whatever the case, there are many complex scientific principles known to modern hyperdrive engineers which allow for many different uses of this faster than light phenomenon.
The use of a hyperdrive by a starship is a fixed, routine process. After a course is laid in, the ship moves to a particular bearing and activates its hyperdrive. The ship then accelerates rapidly, so fast that to passengers the stars outside seem to extend into parallel lines, followed by the final 'jump' into hyperspace when the ship finally leaves conventional existence, or realspace. This phenomenon is known as 'pseudomotion,' as the massive acceleration results in a motion which renders conventional notions of velocity irrelevant. At hyperspeed, the entire universe narrows to a blue-shifted 'tunnel' of high-speed blur, effectively cutting off the ship from normal methods of scanning and detection.
When moving at speeds many times the speed of light, there are many dangers. While any collision or interference at this state is potentially fatal, the effects of gravitational pull on a starship can be particularly devastating, thus a course must be plotted outside the 'mass shadow' or gravity well of large celestial bodies. This has been exploited in many ways through the ages. Hyperspace courses are often plotted using a planet's mass as a backstop, with the hyperdrive's safety systems automatically stopping the ship as it reaches the farthest point of possible travel. Gravity generators can be used to create an artificial 'interdiction field' which stops hyperspace travel in a particular area by mimicking the outer fringes of a celestial body's gravity, useful for both pulling ships out of hyperspace en route and preventing enemies from escaping to light-speed during engagement. Less affluent groups, such as pirates may drag large asteroids into trade routes in lieu of the generator or starship method, providing them with both a means to stop shipping and a temporary base or shield against hostile fire.
Effects on sensors and commsEdit
In addition to navigational hazards, there is also the difficulty inherent in communicating with a starship traveling at hyper-speed. Since ships in hyperspace do not exist in a conventional sense, they are largely cut off from conventional radio or subspace communication, since wavelengths of any signal would be massively distorted if they even reached the vessel. Communications/Hypercomm signals can reach a vessel in hyperspace, however it is very difficult to communicate in even this fashion unless the signal is sent from one end or the other of the traveling ship's course, or between ships on the same course. The same difficulties presented to communication also apply to sensors; it is nearly impossible to maintain sensor lock on a vessel in hyperspace, which makes escape to light-speed a very robust retreat option in most engagements. The only option available for pursuit is generally to plot several courses along the target's last known vector, and try to guess where the ship will come out of hyperspace for course corrections. This is generally a losing strategy, of course, since most ships wishing to avoid pursuit will plot a short jump, followed by a longer one to the destination at a different vector before enemies can arrive. The best option is to locate a homing beacon on the enemy ship, but at large distances only HoloNet-equipped tracking devices are useful, and these are fantastically expensive. An interesting phenomenon associated with hyperspace travel is Croneau radiation. This is a short, but powerful burst of radiation which is generated when a ship enters and leaves hyperspace. It can be detected by properly aligned sensors from some light-seconds away, often well outside normal sensor radius.
Because of the danger of mass shadows (not to mention interdicting pirates), hyperspace courses must be plotted with great caution. Very few beings other than powerful Jedi can react while traveling many times the speed of light, and in any case conventional sensors and communicators cannot receive information faster than light-speed. Even subspace sensors, which operate along an alternate dimension and propagate faster than light, cannot keep up with the vast speeds of hyperspace travel. Thus, precise advance knowledge of the celestial bodies along the way is necessary, in the form of navigational computers. These devices, also known as nav comps or navicomputers by spacers, contain detailed star charts and the ability to make astronavigational calculations quickly from one point to another before the jump is taken. While pilots must still have a basic understanding of astronav skills to operate a nav computer proficiently, they don't need to know the complex physical equations necessary for hyperspeed travel. The internal library charts must be periodically updated, of course, as systems spiral slowly around the galaxy, stars explode and are born, and so on, and so a dedicated explorer and cartographer corps still exists millennia after the first star lanes were plotted. Most star travelers use preexisting, well-known trade routes. This guarantees that interdiction by pirates and celestial bodies is kept to a minimum, help is close by in the case of a malfunction, and travel times can be reasonably predicted.
While hyperspace travel is the primary usage of this phenomenon which binds the modern galaxy together, it is by no means the only one. Hypercomm technology sends signal packets through hyperspace at greater speeds and distances than possible with more conventional subspace transmitters, and with much greater speed than hyperdrive-equipped starships. The HoloNet increases range still further, using an interconnected network of hyperspace beacons to rebroadcast enormous tracts of data over the entire galaxy, allowing instantaneous, full-holo transmission from virtually any subscriber to any other. Under the Empire, the HoloNet was rigorously controlled, and even under the New Republic, the network is fantastically expensive to maintain, and so direct two-way connection is usually limited to government personnel and the wealthy. News, entertainment, and other wide-reaching broadcasts are transmitted throughout the galaxy and repeated on local sector-based subspace networks, however, so every level of galactic society is touched by this communications tool, not simply those with expensive hypercomm systems.