Dust components of Comet Shoemaker--Levy-9 will traverse Jupiter's magnetosphere for an extended period surrounding the July 1994 impact of the nuclear fragments with Jupiter's atmosphere. We focus here on three interactions that are, in principle, visible from Earth: one in which the magnetosphere could affect the comet, one in which the comet could affect the magnetosphere, and one caused by dust impacting the upper atmosphere. These interactions are (1) electrostatic disruption of dust grains, which could permit remote optical imaging of the magnetosphere, (2) energy degradation of trapped relativistic electrons, which might produce observable changes in their synchrotron emission spectrum, and (3) a coma-induced meteor shower in view of Earth-based telescopes. We find these various interactions may be weak, possibly unobservable. If these interactions prove detectable, they can provide unique diagnostic tools for the magnetosphere, the comet/magnetosphere interaction, and the mass flux and size distribution of dust striking the upper atmosphere. ¿ American Geophysical Union 1994