Portal

Portals in Metroid Prime 2: Echoes transported Samus from Aether to Dark Aether, or vice-versa.

There are two kinds of portals: full, man-made portals, and naturally occurring dimensional rifts.

Portals
Portals on Aether are transdimenssional links to the opposing world. Portals are links that help prevent the subject's atoms from being scattered across the interdimensioal void.

Portals where first discovered on Aether as a natural phenomenon after the Phazon meteor impact. After the initial attraction to these strange appearences, the Luminoth began to fear them as an unknown evil poured from them. At first these dark creatures evaporated in Aether's light, but began to overshadow local creatures.

As war began between the Luminoth and the shadowy Ing, the Luminoth developed synthetic portals to venture into the enemies territory. However these portals are unstable and last for only short periods of time.

Portals were built by the Luminoth during the war. The first portal discovered by Samus, in the Agon Wastes, had to be activated through a series of tasks in order to get it solar energy. These portals are always two-way (entering a portal on Aether brings Samus to a portal on Dark Aether, so she can return immediately) and the ones on Dark Aether are invariably protected by a field of light. Samus encounters both naturally formed and synthetic portals on Aether. They must be activated by being scanned.

Rifts
Rifts are naturally occurring portals, appearing as flattened, swirling vortexes. Rifts are activated by firing its related energy at it. Firing light energy at a Light Portal or firing Dark Energy at a Dark Portal can activate them. The Annihilator beam ,however, can activate both portals as it contains both light and dark energy.

Rifts can be one-way, that is, entering a rift on Aether does not necessarily lead to one on Dark Aether. So Samus may enter a rift but not be able to go back where she came, meaning she must find another gateway out of that Dimension.

Space Pirate Use
The Space Pirates found that there were large amounts of Phazon on Dark Aether, and started venturing there. In the Agon Wastes, they had a portal site, then inactive. Samus turned it on, releasing War Wasps into the room at the same time.