My favorite moon — The Sponge of Saturn 🪐 Remarkably, 40% of Hyperion’s interior is empty space between icy fragments, and this also explains its stark surface texture. The Cassini spacecraft found cup-like craters filled with hydrocarbons and an extremely low density… https://t.co/zc29Mb3UwC https://t.co/ximXSs1YHm