Hyperion: the "sponge-like" moon

Da "NASA - Picture of the Day" del 26 Luglio 2005:"Recent HR images from the Cassini spacecraft orbiting Saturn show Hyperion to be an even stranger place than thought before. Previously, it was known that the length of a day on Hyperion is unpredictable. The moon's highly elliptical orbit around Saturn, its highly non-spherical shape and its locked 4:3 orbital resonance with Titan torque Hyperion around so much it is hard to predict when the Sun will rise next. The newly imaged craters on the unusually coarse surface are surely the result of impacts, but for some reason have dark centers. The low density of Hyperion indicates it might even be a spelunker's paradise, riddled with tremendous caverns".

Nota: è la prima volta che la NASA dice espressamente che i crateri visibili sono "surely the result of impacts". A parte l'ovvia assurdità di una simile certezza (irraggiungibile per definizione), molti Ricercatori credono che gli impatti ebbero un ruolo MARGINALE nella definizione di questo ed altri mondi...