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MAIN MOONS: Titan
Iapetus
Dione Enceladus
Mimas
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IAPETUS
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· Your travel guide to the Solar System ·
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DEFINITION
Iapetus is a moon of Saturn, about a third the size of Earth's moon.
REASONS TO VISIT
- Solve the riddle of Iapetus's twin faces
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WHAT TO SEE
A moon of two halves
Iapetus's has two distinct halves. One half is bright, cratered and probably covered in ice.
The other half of the surface is ten times darker and covered with a mystery material yet to be identified.
The contrast between the two hemispheres is so great that earlier astronomers could only see the moon when the bright half was facing towards Earth.
The reason for this striking difference is unknown. It is possible that Iapetus picks up debris as it orbits. Another theory is that the darker regions are caused by lava brought to the surface by volcanic activity.
SPOTTING IAPETUS FROM THE EARTH
Iapetus is not visible from the Earth with the naked eye, but can be seen with a telescope.
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TRAVEL INFORMATION
Before you leave
Unlike most of Saturn's moons, Iapetus orbits at an angle of 15° to Saturn's equator. Make sure you time your journey correctly if you want to avoid wasting fuel flying out of the plane of planetary orbit.
LOCAL HISTORY
In Greek mythology, Iapetus was a Titan - one of a race of god-like giants whose parents were Uranus and Gaia.
Discovery
The satellite was discovered by Giovanni Domenico Cassini in 1671.
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