Image of a galaxy (center) with incoming cold gas flow produced by rendering the gas distribution in a supercomputer simulation of a forming galaxy. A stream of primordial inflowing gas is illuminated from behind by a distant background quasar (lower left; quasar added by an artist, along with the starry background). Using data collected from the W. M. Keck Observatory, researchers have now made the first unambiguous detection of this accretion of pristine gas onto a star-forming galaxy that was previously theorized to exist based on cosmological simulations of galaxy formation.