• Key Information

  • Iapetus

  • Type
    Moon (of Saturn)
  • Diameter
    912.7 miles
  • Distance from Saturn
    2,212,590 miles
  • Orbit Time
    79.3 days
  • Length of Day
    79.3 days
  • Time around Sun
    29.4571 Earth years
  • Atmosphere
    None
  • Temperature
    -297 to -225 °F
  • Date of Discovery
    October 25, 1671, G. D. Cassini
  • Learning Point
  • Discovered by Giovanni Cassini in 1671, Iapetus has been a fascinating moon of Saturn from very early on. Cassini realised the moon had two colours as it was difficult to find it on one side of Saturn, which is the result of Iapetus' rotation being locked to the its orbit around Saturn.
  • Project
  • Draw Iapetus around Saturn with its two colours and the ridge on the side of the moon.
  • Location
  • Located in
    Solar System, orbiting Saturn
  • Fun Facts
  • Iapetus is the 3rd largest of Saturn's moons and the 11th largest in the Solar System.
  • It is thought that Iapetus may have been a very early moon of Saturn, and not formed through collisions as has been suggested for other moons of Saturn.
  • Iapetus is sometimes described as walnut-shaped because it has squashed poles and a bulging equator due to the large ridge that runs around part of the moon.
  • The largest crater on Iapetus, Turgis, is 360 miles wide and the edges are 9.3 miles high.