Iapetus (moon)
Iapetus ( /aɪˈæpɨtəs/;Greek: Ιαπετός), occasionally Japetus ( /ˈdʒæpɨtəs/), is the third-largest natural satellite of Saturn, and eleventh-largest in the Solar System. Compared to Earth's moon, its radius is about 42% and its density is about 32.5% resulting in a mass of about 2.5% of Earth's moon. It was discovered by Giovanni Domenico Cassini in 1671. Iapetus is best known for its dramatic 'two-tone' coloration, but discoveries by the Cassini mission in 2007 have revealed several other unusual physical characteristics, such as an equatorial ridge that runs about halfway around the moon.
Read more about Iapetus (moon): Discovery, Name, Physical Characteristics, Temperatures, Orbit, Exploration