P149:4, 13:3.1 The seven luminous spheres of the Eternal Son are the worlds of the seven phases of pure-spirit existence. These shining orbs are the source of the threefold light of Paradise and Havona, their influence being largely, but not wholly, confined to the central universe.
P149:5, 13:3.2 Personality is not present on these Paradise satellites; therefore is there little concerning these pure-spirit abodes which can be presented to the mortal and material personality. We are taught that these worlds teem with the otherwise-than-personal life of the beings of the Eternal Son. We infer that these entities are being assembled for ministry in the projected new universes of outer space. The Paradise philosophers maintain that each Paradise cycle, about two billion years of Urantia time, witnesses the creation of additional reserves of these orders on the secret worlds of the Eternal Son.
P149:6, 13:3.3 As far as I am informed, no personality has ever been on any one of these spheres of the Eternal Son. I have never been assigned to visit one of these worlds in all my long experience in and out of Paradise. Even the personalities cocreated by the Eternal Son do not go to these worlds. We infer that all types of impersonal spirits -- regardless of parentage -- are admitted to these spirit homes. As I am a person and have a spirit form, no doubt such a world would seem empty and deserted even if I were permitted to pay it a visit. High spirit personalities are not given to the gratification of purposeless curiosity, purely useless adventure. There is at all times altogether too much intriguing and purposeful adventure to permit the development of any great interest in those projects which are either futile or unreal.