 The many stars and dust and gas clouds that make up NGC 5585, shown here in this Hubble image, contribute only a small fraction of the total mass of the galaxy. As in many galaxies, this discrepancy can be explained by the presence of dark matter. The stellar disc of the galaxy extends over 35,000 light-years across. When compared with galaxies of similar shape and size, 5585 stands out by having a noticeably higher proportion of dark matter.