It came up tangentally in IRC, so here's some more gatechat. The following is mostly verbatim from the Eclipse Phase book Gatecrashing, used under Creative Commons BY-NC-SA 3.0 (oddly enough, the came CC license Fenspace is under. Synergy.) with a little remixing by yours truly to fit the established paradigm:
FenWiki - Your One-Stop Shop for Fenspace Information
"I. Drink. Your. NERDRAGE!"
Quote:Though the Oberon gates are all very similar in look and function, in truth there are many notable differences between individual structures. First among these is size. Some of the gates are quite large, with the main spherical cage having a radius of over 100 meters. On the other hand, most gates are significantly smaller, with the lower end gates having a radius of approximately 15 meters across. There is some speculation that the gate sizes may be programmable, though no one has succeeded in reshaping one yet, or at least acknowledged such to the research community. It is possible to manipulate the wormhole size so that it is smaller than the gate; this is in fact standard procedure when connecting to unknown locations. In these cases, the wormhole is intentionally kept just wide enough to stick a microsensor through, while preventing anything larger from coming through.Mr. Fnord interdimensional man of mystery
All gates have the same basic form: a rough sphere of interlocking angled arms, like a round patterned cage. These black arms are solid and composed of an unknown form of stable and programmable exotic matter. Despite several years of study, the exact composition continues to spur a raging debate in materials science and physics circles, and there seems to be some evidence that different gates may actually be composed of different substances, or perhaps change composition over time. The arms move and change shape when new destinations are programmed into the gate, though it is interesting to note that set destinations do not always produce the same arm configurations.
Physically, gate arms have a polished metal look, and they seem to be impervious to signs of aging or physical damage, having an inherent self-repair function. Nobody has yet been willing to risk damaging a gate—at least that they’ve admitted—and so no one is quite sure just how resilient to damage these structures are. Analysis of the material properties suggests they can easily shrug off concentrated burns from even our heaviest beam weapons and are all but immune to personal weapons fire.
To viewers, the wormhole within the cage appears as a pure black sphere of nothingness, rippling with green static energy. Like the cage, the wormhole itself is effectively invisible on various electromagnetic wavelengths. The wormholes bleed Hawking radiation, however, so they show up very brightly and with a distinct signature on thermal scans.
The unknown fields surrounding each wormhole effectively keep the environments at each end of the throat or tunnel from interacting. This means that gatecrashers do not need to worry about suddenly losing atmosphere or getting sucked through if they open onto a vacuum environment, nor do they need to worry about the remote location’s hostile atmosphere, radiation, or gravity until they pass through. No sensory data passes through the wormhole; it is impossible to see, hear, or otherwise sense what is on the other side without passing something through.
FenWiki - Your One-Stop Shop for Fenspace Information
"I. Drink. Your. NERDRAGE!"