article_snippet.sent: It looks, and sometimes acts, like a huge sponge floating in space.
article_snippet.sent: But this crumpet-like rock is in fact one of Saturn's outer moons, measuring 255 by 161 miles (410 by 260km).
article_snippet.sent: a huge sponge floating in space: this image taken by Cassini as it performed a flyby of the satellite shows one of Saturn's outer moons, measuring 255 by 161 miles (410 by 260km). 
article_snippet.sent: This low density also means that This low density is composed largely of water ice with only a small amount of rock.
article_snippet.sent: Because of This low density the entire moon is porous, like a sponge, with well-preserved craters of various sizes packed together across a sponge surface. 
article_snippet.sent: This is comparable to what happens when you rub your hair against a balloon, or when a shirt or blouse rubs against a sweater,' said Professor Tom Nordheim at University College London.
article_snippet.sent: Because of Its odd, almost 'bubbly' appearance the entire moon is porous, like a sponge, with well-preserved craters of various sizes packed together across a sponge surface.
highlights_snippet.sent: Esa bubbly appearance is due to Esa having a very low density for Esa size .
  