Observations of the Io plasma torus made before, during, and after the
impact of Comet Shoemaker-Levy 9 with Jupiter reveal no comet-induced
changes. Three weeks of high spectral-resolution ground-based visible
spectroscopy show no changes larger than typical day-to-day variation
s in the torus densities, ion temperatures, or rotation velocities. Co
mparison with six months of identically obtained data from 1991 and 19
92 also shows no differences.