Bizarre boulders litter Saturn moon's icy surface

[emad]

NewScientist.com news service
Stuart Clark



The Cassini spacecraft has coasted to its closest encounter yet - skimming just 175 kilometres above Saturn's icy moon Enceladus. But astronomers are at a loss to explain its observations.

On 14 July, Cassini swooped in for an unprecedented close-up view of the wrinkled moon. Its Imaging Science Subsystem (ISS) camera has since returned pictures of a boulder-strewn landscape that is currently beyond explanation. The "boulders" appear to range between 10 and 20 metres in diameter in the highest-resolution images, which can resolve features just 4 m across.

“That’s a surface texture I have never seen anywhere else in the solar system,” says David Rothery, a planetary geologist at the Open University in Milton Keynes, UK.

Cracks crisscross Enceladus's surface - possibly as a result of the moon being repeatedly squeezed and stretched by the gravity of Saturn and other moons nearby. But Rothery points out the boulders avoid - rather than fill - the cracks. This might indicate that the fracturing took place after the boulders had already formed.

http://www.newscientistspace.com/article.ns?id=dn7692

[trotsky]

1. Is Enceladus in or near a ring?

Maybe it's collected ring debris, gently so as not to cause lots of impact craters?

[freedomburn]

2. Or maybe the Progenitors were just trying to be tidy.. eom