Authors: C C Porco; E Baker; J Barbara; K Beurle; A Brahic; J A Burns; S Charnoz; N Cooper; D D Dawson; A D Del Genio; T Denk; L Dones; U Dyudina; M W Evans; B Giese; K Grazier; P Helfenstein; A P Ingersoll; R A Jacobson; T V Johnson; A McEwen; C D Murray; G Neukum; W M Owen; J Perry; T Roatsch; J Spitale; S Squyres; P C Thomas; M Tiscareno; E Turtle; A R Vasavada; J Veverka; R Wagner; R West Journal: Science Date: 2005-02-25 Impact factor: 47.728