Iapetus
Iapetus
Moon of Saturn
Iapetus facts
- Orbits
- Saturn
- Distance from Saturn
- 3,560,800 km (61.1 Saturn-radii)
- Orbital period
- 79.3 days
- Diameter
- 1,469 km
- Mass
- 1.81 × 10²¹ kg
- Orbital inclination
- 15.47°
- Tidally locked
- Yes
- Discovered
- 1671, by Giovanni Cassini
Iapetus orbits Saturn
Watch Iapetus (highlighted) circle Saturn. Press play; the moons run at their real relative speeds.
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About Iapetus
Iapetus is Saturn's oddest large moon: one hemisphere is as dark as coal while the other is as bright as snow, a contrast Cassini noticed in the 1670s. It also has a strange ridge of mountains running along its equator, giving it a walnut-like shape.
- Named after a Titan of Greek myth
- Discovered: 1671, by Giovanni Cassini
Iapetus: frequently asked questions
- What is Iapetus?
- Iapetus is Saturn's oddest large moon: one hemisphere is as dark as coal while the other is as bright as snow, a contrast Cassini noticed in the 1670s.
- What planet does Iapetus orbit?
- Iapetus orbits Saturn at an average distance of about 3,560,800 km, completing one lap every 79.3 days.
- How big is Iapetus?
- Iapetus has a diameter of about 1,469 km and a mass of roughly 1.81 × 10²¹ kg.
- Why is Iapetus famous?
- Iapetus's claim to fame: a two-toned moon with one hemisphere dark as coal and the other bright as snow, plus a towering equatorial ridge.
See Iapetus in motion
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Data from NASA/JPL and NSSDCA. Source.