General speculations about the nature of the world are as old as the Greek pre-Socratic philosophers, but a truly scientific cosmology could not be formulated until there was some knowledge of the basic laws of nature. Isaac Newton's discovery of universal inverse-square-law gravity afforded the first serious opportunity for such an endeavor. Because gravity is attractive, an immediate problem was to explain why the universe did not collapse in upon itself. Planetary motions stopped this happening in the solar system, but what about the "fixed stars"? The answer first suggested was that in a universe of infinite extent, populated uniformly by stars, the attractive forces in different directions would cancel each other out, giving equilibrium.

However, there was a problem with the idea of a limitless cosmos. Every line of sight would have to terminate somewhere on the surface of a star. In 1823 Wilhelm Olbers pointed...