New theory may explain the variety of Saturn’s moons

Nature : A new model of Saturn’s moon system attempts to explain why the six midsized moons have such a wide range of characteristics. The modelâmdash;proposed by Erik Asphaug of the University of California, Santa Cruz, and Andreas Reufer of the University of Bern in Switzerlandâmdash;suggests that four earlier large satellites merged approximately 3.8 billion years ago. The merger, which resulted in the formation of Titan, could have been caused by instability from the merging of the orbits of Uranus and Neptune. The debris left over from the formation of Saturn’s largest moon may have then formed six midsized moons. Asphaug and Reufer believe that the model also explains Titan’s elongated orbit. The theory has drawn criticism, however, for being overly simple. Some astronomers believe that the debris would have just accreted onto Titan and not formed the other moons.