what is Iapetus: a modified natural satellite of Saturn or even, a completely artificial moon?
The prime reason I cannot believe that the geometry we now see all across the surface of Iapetus represents mere surface installations comes down to essentially one word: gravity. Iapetus, with a gravitational attraction 1/40th that of Earth (1/7th our own Moon), simply cannot hold any reasonable atmosphere for any length of time. That would make the extensive geometry (surface constructions) as we see on Iapetus totally impractical as former surface habitations. This concept of retainable atmospheres is not new in astrophysics; Sir James Jeans was calculating and writing about planetary and satellite atmospheric escape rates in the early 20th Century, using the newly-discovered atmosphere of distant, low-mass Titan (in 1908) as theoretical confirmation of his calculations regarding how a planets/moons atmospheric temperature (which determines the average speed of gaseous molecules and atoms below depending on their mass), coupled with its escape velocity (related to surface gravity),
