Spongy-looking Hyperion tumbles into Cassini's view

"The moon's spongy-looking exterior is an interesting coincidence, as much of Hyperion's interior appears to consist of voids. Hyperion is close to the size limit where, like a child compacting a snowball, internal pressure due to the moon's own gravity will begin to crush weak materials like ice, closing pore spaces and eventually creating a more nearly spherical shape."

An alert reader sent me the above article. Of course, there are those (I won't name any names) who might suggest that the spongy-looking exterior is anything but an "interesting coincidence" and that Hyperion is in fact artificial.