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IAPETUS

A remarkable moon of Saturn known for its dramatic two-tone surface and enormous equatorial ridge.
Iapetus — NASA / Cassini
IAPETUS · NASA / CASSINI
1,469 km
DIAMETER
3.56 million km
DISTANCE FROM SATURN
79.3 DAYS
ORBITAL PERIOD
1.09 g/cm³
AVERAGE DENSITY
ICE + ROCK
MAIN COMPOSITION
15.5°
ORBITAL INCLINATION
THE TWO-TONE MOON
Iapetus is one of Saturn's most unusual moons. Its surface has an extreme contrast between a very dark region and a much brighter icy region. The dark material is concentrated on the leading hemisphere, creating the famous two-tone appearance of Iapetus. Iapetus also has a spectacular equatorial ridge that stretches for hundreds of kilometers across its surface. The moon is tidally locked to Saturn, so the same side always faces the planet.
TWO-TONE SURFACE
One hemisphere is extremely dark while the other remains bright and icy.
EQUATORIAL RIDGE
A huge ridge follows much of Iapetus' equator and rises several kilometers above the surrounding terrain.
DISTANT MOON
Iapetus orbits much farther from Saturn than Rhea, Titan, Enceladus and Mimas.
DID YOU KNOW?
Iapetus has one of the most dramatic light-and-dark surfaces in the Solar System.
IMAGE: NASA / JPL-CALTECH / SPACE SCIENCE INSTITUTE / CASSINI
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