The Aether is a universe of effectively limitless energy, discovered by the Yamatai Star Empire in YE 20. Since then, aether has become the cornerstone of the SARPiverse. As technology grew, aether-powered generators became the primary power source of faster-than-light starships of all major nations, and then in increasingly smaller applications.
Taken from the thread "Speed of Aether," Wes described aetheric energy this way:
Aether is basically energy and/or an energized matter/anti-matter plasma that starts reacting as shortly after it's pulled out of the aether. Aether energy (e.g. white beam) moves at light speed, and aether plasma moves however fast you can push it with your coil gun, although if you are producing enough aether plasma, you won't have to push because it'll push you (e.g. aether plasma engines).
I always figured aether energy consists of a wide mix of energy types (basically a full EM spectrum) rather than any particular type (e.g. gamma rays). Scalar waves travel at light speed and cannot be blocked by anything that doesn't block the force of gravity.
Think of aether devices as faucets that pierce the dimensional branes and deliver energy on tap. You can get as much energy as you ask for, up until the point your device can't take anymore. The smallest aether generators are about the size of a lunchbox. The equipment used determines the power and efficiency that a device can harness that power.
With a bomb, one opens a bigger channel than a device could possibly handle, causing a brief but devastating dump of energy into regular space-time. Aether grenades exist, but are fairly rare. Much more common are starship-fired aether torpedoes, such as the AS-7 or the Ke-Z1.
Aether can also be drawn and expelled out of a ship to provide propulsion, such as with Turbo Aether Plasma engines.