'M' picture showing pattern of stars. Historical artwork by the German astronomer and mathematician Johannes Kepler (1571-1630). 'M' stands for mundus, meaning world, and marks the location of our star, the Sun, in relation to others around it. This is meant to illustrate the problem with the theory that existed at the time that our uniform starry universe is infinite, as wherever you look you should be able to see a star. However, this is not the case and there are vast areas devoid of light in the night sky, a paradox that troubled astronomers for over one hundred years. Published in Kepler's Epitome of Copernican Astronomy in 1627.