http://arxiv.org/PS_cache/astro-ph/pdf/0504/0504653.pdf Title: Solving the mystery of Iapetus Authors: Paulo C. C. Freire Comments: Submitted to Journal of Geophysical Research - Planets Since the discovery of Iapetus by G. D. Cassini, in 1672, it has been known that the leading hemisphere of this Saturnian satellite is one order of magnitude darker than the trailing hemisphere. Since the Cassini spacecraft entered the Saturnian orbit, several high-quality images of the dark hemisphere of Iapetus have been obtained, in particular during the Dec 31 2004 flyby of this satellite. These images revealed the presence of a large equatorial ridge in the dark hemisphere of Iapetus. We propose that this ridge and the dark coating of the hemisphere on which it lies are intimately interlinked and are the result of a collision with the edge of a primordial Saturnian ring, ultimately caused by a sudden change in the orbit of Iapetus. The model naturally explains all of the the unique features of this satellite; it is probably the solution to one of the oldest mysteries in solar system astronomy. This paper discuses some of the possibilities for Iapetus orbit change and its collision with saturns rings, but did saturn have more rings in one stage of its evolution?