From National Geographic News:
Despite its bathtub-ready appearance, Hyperion—Saturn's largest irregularly shaped moon—is anything but spongy.
High-resolution images taken by NASA's Cassini spacecraft—including the picture above taken in 2005—suggest the satellite's cuplike craters are reservoirs for hydrocarbons. The finding could mean that the ingredients needed for life as we know it may be more common in our solar system than previously thought, according to NASA.
Dark material spotted at the bottoms of some of the moon's craters has the same chemical signature as hydrocarbons, NASA scientists said. These organic molecules—made of hydrogen and carbon—are also found in comets, meteorites, and galactic dust.What does this mean? What makes up the components of life as we know it not only survive in the harsh environment of space (which we already know) and that these elements are pretty common. All that has to happen for life to occur are temperature, a food source and couple geological ages to get the soup cooking.
Also, we didn't know Hyperion was so oddly shaped before. The Cassini spacecraft first took pictures of the small moon in 2005-2006. Scientists think the porous, sponge-like surface is due to the porous nature of the rock - when an object hits the surface it plows deep into the moon, leaving the tubular craters. Early in Hyperion's life it had pockets of CO2 under its surface, which eventually evaporated away. That left large empty spaces near the surface, weakening the rock.
New Scientist article