
The Age itself is that of a large island of rust colored rock jutting out from a large expansive sea. The island itself is riddled with tunnels and valleys, with water flowing through it, as well as lava laying underneath it, to allow all kinds of energy to be harnessed to power future motion.
Voltaic was one of the lesson-Ages Linked to from J'nanin. This Age was written by Atrus to display the concept that Energy Powers Future Motion. The sons first had to power up the various forms of energy that were built into the Age. By doing this, they were able to create the necessary conditions needed to make the Airship function, which in turn would take them to where they started, and reveal to them the concept they needed to learn.
The name of the Age itself is presumably a reference to the photovoltaic effect, first observed by Einstein.