The puzzle as to just why the sky is dark at night, given that there are so many stars, has been around at least since Newton. This article summarizes six cosmological models that have been used to attempt to give an account of this puzzle including the Copernican universe, the Newton-Halley universe, the nineteenth century "one galaxy" universe, the Hubble many galaxies universe, the steady state universe of Fred Hoyle and the contemporary big-bang universe. In showing some of the simple arguments and calculations we hope to offer students of astronomy some easy approaches to this fascinating topic.