Teleportation

"You mean it's working? For real, this time? Because... I still have nightmares about that cat!"

- Barney Calhoun

Teleportation, also known as displacement, is a means of transferring matter between two locations or dimensions, regardless of their proximity. It is one of the most pivotal themes of the Half-Life universe.

Overview
Whether by paranormal means, or by technological artifice, teleportation is usually achieved instantaneously. The most common and popular form of teleportation is to use a portal; essentially two connected gateways, which allow an object entering one gateway to leave via the other.

Another method was investigated by Black Mesa, and later improved upon by the Resistance.

Black Mesa


Teleportation was a major field of study at Black Mesa, and their portals were used primarily in the procurement of Xen Crystals, as they were used to transport scientists to and from the Borderworld for research and analysis. The portals can be used to travel between Xen and Earth, however they do not allow for travel within the same dimension. Both Gordon Freeman (through the Black Mesa's Lambda Core teleport) and Barney Calhoun traveled to Xen through such a teleport, to escape from Black Mesa before its destruction.

The Displacer, found and used by Adrian Shephard, can also allow for dimensional travels, although how a hand-held device is capable of teleporting itself and the user into Xen and back using internal power is a mystery.

During his brief visit to Xen, Barney is also required to activate and calibrate a "focal point", which was then used by Doctor Rosenberg to teleport several members of the science team outside of Black Mesa.

Aperture Science


Research into portal technology by Aperture Science allowed travel within the same dimension. Portals could be controlled and created by the Aperture Science Handheld Portal Device, and used as a quick method of travel over possibly unlimited distances. Through the use of the ASHPD, Chell could make objects exist in two dimensions simultaneously.

These portals follow a more generic portal style, where light is able to enter the portal and send an image of the other side. They also allow for a more instantaneous transit between the portals, as it is simply a matter of walking in and appearing out of the other one. The ability to place them at will on most flat surfaces also makes these portals much more versatile and efficient.

Resistance and Combine
During The Uprising, the Resistance was able to develop new advancements in portal technology that allowed for single-dimensional travel. The Combine, developing alongside the Resistance, were able to make developments, however were still unable to discover the means of single-dimension teleportation, and were forced to use much slower and conventional means of transportation if they wanted to stay within a single dimension.

The teleport in Kleiner's lab was perfected upon Gordon's arrival in City 17, and it was inaugurated by Alyx Vance, who had a successful transit to Black Mesa East. However, being fragile, the telelporter was damaged by Lamarr during Gordon's attempt, and he was teleported instead outside of the lab.

The Resistance's discovery was major, as it put them one stride ahead of the Combine in the fight for Earth. It must be noted however, that human-made portals are able to accomplish this feat by using the dimensional borderworld Xen as a relay; in the words of Judith Mossman, "we figured out how to use Xen as an unexpressed axis, effectively a dimensional slingshot so we can swing around the borderworld and come back to local space without having to pass through". This method of using an "Unexpressed Axis" centered on Xen removes the need to travel through it or to use a focusing device (like the one activated by Barney Calhoun), but instead use a modulator to emulate its effects.

Additionally, teleporters are used to supply Freeman with Magnusson Devices during the Combine raid on White Forest. These teleporters are smaller and portable, allowing them to be placed in the surrounding wilderness and regularly replenished with the devices.

The Combine also housed their own teleport in the Depot, where it is seemingly used for transporting prisoners. When Alyx and Gordon visit Nova Prospekt to rescue Eli Vance, they are required to use this teleport to return to Kleiner's lab. This plan is waylaid, however, as Judith Mossman uses it to transport Eli to the Citadel. When the teleporter is finally recharged, Alyx and Gordon end up in City 17 a week later.

Using a different technology to the Resistance teleporters, the Combine were able to covertly work on same-dimensional travel, however the device was not able to teleport large masses, and required a long time to recharge. As oppose to the "sling shot" method, they used "string-based" technology.

Both teleporters are much larger than Xenian portals, and require the payload to be lifted above the ground before the data is transmitted. This apparent inefficiency is the primary reason for the Combine's eagerness to uncover the Borealis, in order to speed up and advance their travel on the Earth's surface.

Xen


Xen creatures are also able to use portals to travel between worlds; after the Resonance Cascade, they can be seen teleporting in and out of the Black Mesa Research Facility. Their ability to do so made their siege on Black Mesa all the more easy, as they were able to teleport into almost all areas of the facility. During the events of Half-Life 2, they cannot be seen using portals to travel to Earth.

Xen also features several small monolithic teleports, portals, as well as a larger teleport leading to Nihilanth's lair.

After Gordon is trapped in stasis by the G-Man, just before the destruction of the Citadel's core, he is rescued by numerous Vortigaunts, who teleport him and Alyx from wherever they are, to next to the base of the Citadel.

Superportal
As its name suggests, this is a considerably larger portal, capable of transporting much larger volumes of matter over greater differences.

When Alyx and Gordon escape from City 17 during the Portal Storms, they see in the distance the remains of the Citadel, and the infant superportal, which was said if it were to open, would allow Combine units to sweep in and recapture earth. However, Superportals take a while to gain strength and eventually open.

List of appearances

 * Half-Life: Day One
 * Half-Life
 * Half-Life: Opposing Force
 * Half-Life: Blue Shift
 * Half-Life: Decay
 * Half-Life 2
 * Half-Life 2: Episode One
 * ApertureScience.com
 * Portal
 * Half-Life 2: Episode Two
 * Portal ARG
 * Portal 2