What is the dark material at the impact sites?
The dark semicircles south of the impact points are probably an ejecta blanket composed of fine material condensed from the plume. This material is either from the comet itself or from Jupiter and is suspended in the upper atmosphere. Some scientist refer to it as soot. In the infrared they look bright because of reflected sunlight and in the visible spectral region they are generally darker than the Jovian clouds. The composition of the plumes was investigated by spectroscopy in many different wavelengths. No new molecules have been found but it is expected that further analysis will eventually make it possible to document chemical processes that took place. The following elements and molecules have been seen in the spectra: Li, Na, Mg, Mn, Fe, Si and S; NH3, CO, H2O, HCN; H2S, CS, CS2, S2; CH4, C2H2, C2H6, and possible others [56].
