A Close Look at Saturn’s Sponge Moon

by Nancy Atkinson on August 26, 2011

This raw, unprocessed image of Hyperion was taken on August 25, 2011 and received on Earth August 26, 2011. Image credit: NASA/JPL-Caltech/Space Science Institute

It might be one of the weirdest-looking moons in the solar system: Saturn’s moon Hyperion looks like a giant sponge. Additionally, its eccentric orbit makes it subject to gravitational forces from Saturn, so it is just tumbling along, almost out of control. Just yesterday, August 25, 2011, the Cassini spacecraft made a relatively close flyby of Hyperion (24,000 km 15,000 miles away) and took some amazing images.

“Hyperion is a small moon … just 168 miles across (270 kilometers)… orbiting between Titan and Iapetus,” said Carolyn Porco in an email. Porco is the Cassini imaging team lead. “It has an irregular shape and surface appearance, and it rotates chaotically as it tumbles along in orbit, making it impossible to say just exactly what terrain we would image during this flyby.”

See some more of the shots below:

Side view taken by NASA's Cassini spacecraft of Saturn's moon Hyperion. Image credit: NASA/JPL-Caltech/Space Science Institute

Scientists say this flyby’s closeness has likely allowed Cassini’s cameras to map new territory. At the very least, it will help scientists improve color measurements of the moon. It will also help them determine how the moon’s brightness changes as lighting and viewing conditions change, which can provide insight into the texture of the surface. The color measurements provide additional information about different materials on the moon’s deeply pitted surface.

A darker view of Hyperion. Credit: NASA/JPL-Caltech/Space Science Institute

NASA's Cassini spacecraft obtained this unprocessed image of Saturn's moon Hyperion on Aug. 25, 2011. Image credit: NASA/JPL-Caltech/Space Science Institute

The next closest pass of Hyperion is coming up again soon: Sept. 16, 2011, when it passes the tumbling moon at a distance of about 36,000 miles (58,000 kilometers).

See more raw images at the CICLOPS website.


Nancy Atkinson is Universe Today's Senior Editor. She also works with Astronomy Cast, and is a NASA/JPL Solar System Ambassador.

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