Published online by Cambridge University Press: 30 March 2011
The diffuse interstellar bands (DIBs) have been known of since 1922, but their carriermolecules remain unidentified to this day. We present a brief history of DIB observations,followed by a list of constraints any suggested origin must face, and finally a preview ofcurrent research for ultraviolet DIBs using the Cosmic Origins Spectrographon the Hubble Space Telescope. We conclude that PAHs areconsistent with all the listed constraints, but that PAHs may not be the only molecularspecies responsible for the DIBs.