Oa is the centre of the known universe, or at least the centre of the known universe 4 billion years ago, but after four billion years of mapping its probably not exactly right smack in the centre any more, although if that was true, then there would always be more green lantern sectors, unless all 3600 sectors get a little bigger, get gerrymandered every time the guardians publish a new star atlas... In Star Trek Earth is the Center of the universe. Sector 001. Its because of where the map makers started mapping, rather than Earth actually being the centre of the universe. The third world ended when the God World blew up. Like a cracked egg half the God Planet was New Genesis, and the other half was Apocalips. The new universe, the Fourth World sprang fourth from the Third World's exploding Godworld. How close are New Genesis and Apocolips? If they were made by the big bang, the detonation of the God Planet, then yes, very briefly 18 billion years ago both new planets were there at the the center of the universe, but forces threw them both far far away, long long ago from the creation point. Maybe that's what the fire pit is for? Darksied is trying to take Apicolips back to the origin point of the Universe, but High Father is not?