The Planet Oa
Ancient History
Oa is a planet that lies in the center of the universe and occupied to a race of blue-skinned powerful humanoids who have dubbed themselves the Guardians of the Universe. Oa's history is not clear; according to some stories, the Guardians originated in a planet called Maltus. These evolved Maltusians later moved to Oa and named themselves Oans. Oa became a convenient base of operations. Other stories had the Oans living there from the beginning. When the scientist Krona tried to discover the creation of the Universe a wave of evil engulfed the worlds and created an Anti-matter Universe of evil. He was exiled for this crime and the Oans tried to protect the Universe.
Oa Now and Then
One of the oldest planets, Oa serves as the home and headquarters of the Guardians of the Universe, who administer the Green Lantern Corps. Oa's star is called Sto-Oa (the "Light of Oa") by the children of the planet's inhabitants.
Oa appears to be mainly a desert-like, lifeless planet. The main feature is the Guardian's city which includes, among other things, the Main Power Battery that is charged by the Guardians with their own unique green energy. The Battery then broadcasts this energy to the personal Power Batteries of all Green Lanterns. The Green Lantern Hal Jordan, under the influence of the evil entity Parallax, killed all but one of the Guardians and most of the Corps before draining the battery of its energy. The planet was later destroyed during a battle between Jordan and his successor, Green Lantern Kyle Rayner.
The planet was reformed sometime later by Jordan's old friend and associate Tom Kalmaku. The Central Power Battery was later recharged and the Guardians resurrected shortly thereafter by Kyle Rayner after he spent some time as the near-omnipotent "Ion".
After attacks by Superman-Prime and the Spider Guild, the Guardians refortified Oa by creating a planetwide armour and defensive system to prevent successful attacks against them. The full capability of the new systems are still unknown. They were not however able to prevent an assault by The Sinestro Corps. Afterward, the Corps doubled its defenses. However, a rogue Guardian, Scar, weakened its defenses for an attack from the Black Lantern Corps.
Void Earth
With the disappearance of Earth's Green Lanterns and no possible explanation as to why or how it happened, the Guardians became rather concerned with Earth's well being and the well being of the sector it belonged too because unlike Earth's heroes; Earth's Villains and Criminals were still present and inciting so much chaos that it was beginning to feed some of their enemies or spill out into the rest of the Universe.
So, somewhat displeased with the choice Hal Jordan's ring had made, Oa's Guardians negotiated with the Human race a sort of agreement that would allow human authorities access to Oa's Sciencells. This not only helped Earth maintain order but preserved the Corps reputation as well as it stood by Earth.
