🌙 Moon
Iapetus
A two-toned moon of Saturn, one half dark and the other bright.
- Size
- 1,500 km across, 12% as wide as Earth
- Goes round Saturn
- every 79.3 Earth days
- Discovered
- 1671, by Giovanni Cassini
Did you know?
- Giovanni Cassini could only see it on one side of Saturn. On the other side its dark half faced Earth, and it seemed to vanish.
- A tall ridge runs around its middle, like the seam on a walnut.
Photographed or visited by
Cassini–Huygens
Thirteen years around Saturn, and a landing on Titan.
Compare Iapetus with EarthSide by side, to scale, in the app
More NASA photos of IapetusStraight from NASA’s image library, in the app
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All of solar system
Mercury
The smallest planet, and the closest to the Sun.
Venus
The hottest planet, hidden under thick clouds.
Earth
Our home, the only world known to have life.
Mars
The red planet, with the tallest volcano in the solar system.
Jupiter
The biggest planet, with a storm larger than Earth.
Saturn
The ringed giant, light enough to float in water.