This figure (below) depicts the changes in an interstellar/cometary ice analog with continued exposure to ultraviolet (UV) radiation as measured by infrared spectroscopy. The infrared spectrum at the top of the figure is that of the starting ice sample before irradiation. The spectra below show the creation of molecules such as carbon monoxide, carbon dioxide, methane, and formaldehyde are caused by UV radiation at 10 K. This is consistent with the observation of such photoproducts in the tail of comets.