The Earth Gateway is a perfect circle 15 feet in diameter, fashioned from a dull blue-gray material that, for the most part, acts like a metal. The "facing surface" of the ring is covered in nodules and writing. The writing is composed of dots, circles, spirals, swirls, and curves. In fact, there is no angle present on the gateway at all – all the contours are smooth and curved. The gate is powered by feeding energy directly onto any of the nodules. Electrical cables, solar energy, a laser beam, microwave transmissions, an open flame – all of these have been tested and can power up the gate, although the more efficient the power source, the less time it takes to charge the gateway. An unpowered gate left in the sun will have enough stored energy for a jump in about a year.
The gate is tough: it would take something along the lines of a nuclear blast or a fuel-air explosive to damage or destroy it (although this is purely theoretical, and based on tests on other artifacts recovered from Antarctica).
The gate’s portal is one-way except for energy transmission. Radio waves and such can pass through a gate in both directions, allowing FTL communication. Any matter trying to enter a gate the “wrong way” simply passes through the ring with no effect. Physically obstructing the space inside the ring will prevent a gate from forming, as will activating the emergency shutdown nodule.
Objects that pass through the ring do not transport until their entire mass has passed over the threshold and the receiving gate has determined that the object will pass through without incident.