The physics of wormhole phenomena have been conjectured since the 20th century (Morris-Thorne wormhole). However, the technology required to allow its actual artificial implementation did not become feasible until centuries later, when negative matter was exploited to this end. It remains to this day the only known means of faster than light mass transportation that does not involve Localized Reality Control Fields (which allow Hyperwarp by increasing the speed of light and other anomalous effects).
In common parlance, these are most popularly referred to as Jump Gates when used in space. However, depending on the locale, other terms, such as Hyper Bridge, Skip Portal, Star Link, and so on may also refer to the same device.
Early Jump Gates could only ever be connected to one other Gate. The quantum entanglement process prohibited a Gate from ever being redirected for use elsewhere. Later refinements in the technology enabled recalibration, though the research for such things was not without its accidents. Still, an unbroken law of physics remains that any given gate can only be connected to one other gate at any given time. In practice this means that to establish a link between two gates, both must be simultaneously free to open. Prior to faster-than-light communication, this usually meant that gates functioned like roadways, always opened to one route, as recalibration would take at least the number of light years for changes to be communicated. In those days, gates were also used as the primary means of interstellar communication.
The Galactic Portal Network consists of thousands of individual Jump Gates designed to serve as a rapid transportation system. By the era of the AEGIS Imperium, the network is so vast that travel between stars has become a trivial affair. Earlier epochs were not so lucky. Before their widespread dissemination, space travel often required the use of advanced stasis technology, or even highly complex intergenerational world ships.
A common strategy for expansion among a number of civilizations involved the use of special Gate Builder Ships, crewless and manned only by autonomous A.I. whose sole purpose was to reach a distant system, and construct a Jump Gate there in preparation for colonization efforts. An extreme case of this would send tiny seedships that upon arrival in a new system would expand to build a macro-scale Jump Gate with the help of an internal micro-scale Jump Gate.
By their very nature, Jump Gates are incredibly important strategic points. Many treaties and conventions have been signed which prohibited acts of war that might damage them, as often the livelihoods of entire systems could be put at risk, and neither side would risk being held responsible for their destruction. More rarely, their strategic demolition has turned the tide of a war.
A peculiar issue with Jump Gates is that there is no way to know what’s on the other side without first activating it. Once activated a Jump Gate takes on the characteristic of appearing almost like a window into a different spacetime, as photons from the other side travel through. It is a well known danger that an active Jump Gate always works both ways, and that any matter within the space between the ‘thread’ that connects the two gates will be annihilated.
Use as Time Machines
Jump Gates are the fundamental technology that allows a sort of time travel, by connecting to a parallel universe at a different time period. This cannot predate the activation of the first gate however. Sending a gate backwards in time is a much more difficult matter.
Jump Gated Ships
An interesting alternative to Gate Builder Ships is to have a Colony Ship with a functioning jump gate while still in-transit. This effectively allows for the colony ship to have a rotating staff that is based on a home planet. It also allows for indefinite resupply of food and fuel.
In fact, as the technology improved to the point that any ship could effectively carry an internal jump gate (often referred to as a portal), the most dramatic effect was on the logistics of space postings. Where previously individuals would have to spend lengthy stretches of time away from home, the capacity for a jump gated crew to rotate on and off the ship at will significantly improved the condition of space travel, removing the need for stasis and suspended animation, as well as the need for ships to be self-sustaining. Furthermore, the ability to funnel supplies to ships instantaneously allowed for ships to function as essentially outposts capable of functioning far distantly and indefinitely without need for returning to base for resupply.
Even just having a single Gate Ship with a fleet allowed for the fleet to be able to function in this way, though for the sake of redundancy it was often wise for every ship to carry an internal jump gate, in case one ship's gate was disabled.
Personal Portals and Travel Booths
The sheer convenience of jump gates eventually led to the development of personal portals in people's homes as well as public travel booths. Both generally involve keying in the target exit coordinates of another portal or booth, with public travel booths usually also coming with an identification and payment process. In eras with such technology, commute times are no longer a function of distance to destination, but merely an issue of the exit portal or travel booth not being available due to high traffic. Thus, whereas in earlier eras, humans waited in their cars or on buses or trains, in these future eras, people generally waited at home or at the waiting area of the public travel booth for their destination to become available. Suffice to say, this was generally much more convenient than previously.