How Iapetus, Saturn’s outermost moon, got its ridge

A team of scientists a team, including William B. McKinnon, PhD, professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, propose an explanation for the bizarre ridge belting Saturn’s outermost moon Iapetus. At one time Iapetus itself may have had a satellite, created by a giant impact with another body. The satellite’s orbit would have decayed because of tidal interactions with Iapetus, and at some point it would have been ripped apart, forming a ring of debris around Iapetus that would eventually slam into the moon near its equator,