Hyperion

saturn · chaotic · unusual

Sponge-like oddball. Hyperion looks like a lumpy potato with holes all through it, making it less dense than water. This weird, porous surface is totally unlike any other moon in our solar system.

Tumbles unpredictably. While most moons spin in steady, predictable ways, Hyperion spins chaotically and randomly flips as it orbits Saturn. Scientists can never predict exactly how it will be oriented from one moment to the next.

First irregular moon. When astronomers discovered Hyperion in 1848, it was the first moon ever found that wasn't round or sphere-shaped. Before this, people thought all moons had to be perfectly rounded.

Smaller than expected. Hyperion measures about 270 kilometers across at its longest point, making it Saturn's eighth-largest moon. Despite its small size, its strange shape and behavior make it one of the most interesting moons to study.

Made of ancient ice. Scientists think Hyperion is mostly composed of water ice and rock, left over from the early solar system. Its unusual shape might have come from a giant collision billions of years ago.