Credit: NASA/JPL/Space Science Institute
Saturn's moon Iapetus has long been one of the most curious objects in the solar system. From Earth, astronomers can see that it has two radically different hemispheres - one bright as snow, the other dark as tar - and up close, things only get weirder. Iapetus bulges at the middle, and has a stark chain of mountains around its equator, lending it the appearance of a giant, battle-scarred walnut.
After modelling the probable history of Iapetus, scientists working with the Cassini spacecraft have come to the conclusion that its past activities may be every bit as peculiar as its current state. It may even be something of the James Dean of extraterrestrial worlds.
"Iapetus spun fast, froze young, and left behind a body with lasting curves," said Julie Castillo, Cassini scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
Read the NASA press release