Look on the Bright Side

The sun shines on Iapetus' lighter surface
The sun shines on Iapetus' lighter surface

Another view of Saturn’s moon Iapetus (see previous post) shows the brighter surface illuminated by the sun, with a section of the darker surface visible near the moon’s equator.

This dual-coloration of the 914-mile-wide moon was first observed by Giovanni Cassini in 1671. Noticing that the moon was only visible when on the western side of Saturn, he concluded that it must have one side much more reflective than the other.

Now, nearly 340 years later, a spacecraft bearing his name is taking photos of the little world as it passes by at a distance of over 732,000 miles.

Raw image: NASA/JPL/SSI

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