What did the first quasars look like? The nearest quasars are now known to be supermassive black holes in the centres of galaxies. Gas and dust that falls towards a quasar glows brightly, sometimes outglowing the entire home galaxy. The quasars that formed in the first billion years of the universe are more mysterious, though, with even the nature of the surrounding gas still unknown. An artist's impression shows a primordial quasar as it might have been, surrounded by sheets of gas, dust, stars and early star clusters. Exacting observations of three distant quasars now indicate emission of very specific colours of the element iron.
Image credit: NASA/ESA/ESO/Wolfram Freudling et al. (STECF)