Cassini gets last look at Saturn’s spongy satellite Hyperion

A picture of Saturn's moon, Hyperion

Hyperion is the largest of Saturn’s irregularly shaped satellites. The Cassini probe snapped this picture from about 34,000 kilometers away during its final flyby May 31.

JPL-Caltech/NASA, Space Science Institute

That’s no space sponge above — it’s a moon of Saturn. Hyperion, one of the oddest-looking moons in the solar system, shows off its bizarrely sculpted surface in new images taken by the Cassini spacecraft, which buzzed the moon for the final time on May 31.

Hyperion would easily float in an adequately sized pool — it’s about half as dense as water. The interior of the moon is highly porous, a network of cavities within a loosely bound pile of ice and rubble. Because the moon is a bit fluffy, incoming meteorites squish the surface rather than excavate it, which contributes to its spongy appearance. 

Christopher Crockett is an Associate News Editor. He was formerly the astronomy writer from 2014 to 2017, and he has a Ph.D. in astronomy from the University of California, Los Angeles.

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