The curious, 20-km tall central ridge of Iapetus, a.k.a. the Voyager Mountains Saturn’s 914-mile (1471-km) -wide Iapetus (pronounced eye-AH-pe-tus) has a particularly curious feature: a chain of 20-kilometer (12-mile) high mountains encircling the moon’s equator. On the anti-Saturnian side of Iapetus, the ridge appears to break up, forming distinct, partially bright mountains. The Voyager I…