What if gravity on architectural worlds is generated by artificial means? They could be hollow or any size required by the “unseen” spiritual administration of a far-flung universe. For example, a Planetary Prince might be given a very small architectural world as the location of his administration orbiting the world of his assignment. Where is Jerusem relative to Urantia according to The Urantia Book? It’s difficult to describe “location” of morontia objects because matter is so diffuse compared to ours in that realm.
Me here: It is not at all or in any way “difficult to describe “location” of morontia objects”! Every place in the universe of universes has a very real and precise location.
Paradise does too!
11:1.2 (118.4)God dwells, has dwelt, and everlastingly will dwell in this same central and eternal abode. We have always found him there and always will. The Universal Father is cosmically focalized, spiritually personalized, and geographically resident at this center of the universe of universes.
11:1.3 (118.5)We all know the direct course to pursue to find the Universal Father. You are not able to comprehend much about the divine residence because of its remoteness from you and the immensity of the intervening space, but those who are able to comprehend the meaning of these enormous distances know God’s location and residence just as certainly and literally as you know the location of New York, London, Rome, or Singapore, cities definitely and geographically located on Urantia. If you were an intelligent navigator, equipped with ship, maps, and compass, you could readily find these cities. Likewise, if you had the time and means of passage, were spiritually qualified, and had the necessary guidance, you could be piloted through universe upon universe and from circuit to circuit, ever journeying inward through the starry realms, until at last you would stand before the central shining of the spiritual glory of the Universal Father. Provided with all the necessities for the journey, it is just as possible to find the personal presence of God at the center of all things as to find distant cities on your own planet. That you have not visited these places in no way disproves their reality or actual existence. That so few of the universe creatures have found God on Paradise in no way disproves either the reality of his existence or the actuality of his spiritual person at the center of all things.
Me here: Same with every single Architectural Sphere in the universes of time! Spatial coordinates and definitive locations easily found by all who need to know or come to visit.
You appear to be inventing things here to support your personal beliefs which contradict the text. Where does it say or infer that any Planetary Prince might ever, under any circumstances, “…be given a small architectural world as the location of his administration”?????!!!!!
Where does it say architectural spheres are hollow?? Who or what is the “unseen” spiritual administration??
The UB clearly states that the architectural spheres are created billions of years before the material, evolutionary worlds. We cannot make the UB say what we want it to say. It says what it says and doesn’t say what it does not. Illogical fantasies about the Papers are no substitute for serious inquiry and research of their actual contents.
I recommend you consider reading the text and asking questions about the text, rather than posting such obvious contradictions of the text. What is the purpose or agenda for such misrepresentation? Such claims show a certain disregard for the very text you cite.
It appears you may only seek some textual confirmation for personal beliefs and prejudices rather than seeking understanding or any discussion of the actual contents of the Papers.
15:7.12 (175.3)If all the projected local universes and their component parts were established, there would be slightly less than five hundred billion architectural worlds in the seven superuniverses.
Me here: 500 billion architectural spheres for 7 trillion evolutionary inhabited worlds (70 +/- per System). The architectural spheres come first, billions of years prior to evolutionary worlds.
Paper 15 offers much regarding gravity throughout the 7 Super Universes.
"Live loyally today—grow—and tomorrow will attend to itself. The quickest way for a tadpole to become a frog is to live loyally each moment as a tadpole."

