According to Professor Scott ( author of the Electric Sun [link to members.cox.net] ), bodies fission to creat more surface area upon which to balance electrical stress. In the case of Comet Elenin, it is coming into the Solar neighborhood from 'way out there', and is finding a LOT of electrical stress in the presence of the much more positively charged inner system bodies. Hence, it is probably splitting, and re-splitting, over and over, to provide more surface area for charge equalization.