Ιαπετού, also known as Iapetus, is one of the largest moons of the planet Saturn. It is notable for its unique two-tone coloration, with one side being very dark and the other much brighter. This striking contrast is thought to be due to the accumulation of different materials on its surface. The moon has a diameter of about 1,471 kilometers (914 miles) and is the third-largest moon of Saturn. Ιαπετού has a distinct shape, resembling a walnut, and features a prominent equatorial ridge. Its unusual characteristics make it a subject of interest in the study of celestial bodies in our solar system.