Sunday 22 August 2021

♄ viii

Discovered by Italian astronomer Giovanni Domenico Cassini in 1671 and later dubbed after the titan Iapetus after the naming convention established by William Herschel—with the antiquated adjectival form of Japetian that points to the conflation of the deity with Japheth, brother of Moses—and explored more thoroughly during the 2007 mission named after its discoverer, the satellite of Saturn first loomed large in human imagination when on this day in 1981 the Voyager 2 probe relayed the featured image back to Earth. The prominent equatorial ridge, named the Voyager Mountains after the photograph are among the highest in the known Solar System, and ring the object almost perfectly, giving rise to the theory that the feature is a reabsorbed ring and the probable but yet unseen occurrence of sub-satellites.