If the stars were part of a star system, how could it be measured and its boundaries defined? William Herschel used a handmade, twenty-foot telescope to chip away at what he called the "construction of the heavens." He swept the skies to record the arrangement of the visible stars, and in 1785 published our first map of the galaxy. It placed the sun quite centrally within it, in what seemed a philosophical return to the earth-centered system that featured "us."

Another of Herschel's great contributions was to establish that our solar system is moving through space. Wright and Kant had assumed its motion, but Herschel proved it through rigorous analysis of telescopic observations. He determined that the sun was moving toward the constellation Hercules. Along with our sun, we were on our way somewhere, moving vast distances through galactic space.