About the Cover

This IR image shows a bow shock caused by stellar wind emanating from a bright star. Interstellar shocks can also be created by the exhalations of dying stars. As shocks propagate through the interstellar medium, they can give rise to new stars that are enriched with heavier elements. On page 36 , Cecilia Ceccarelli and Claudio Codella discuss how interstellar shocks influence the composition of the Milky Way. (Courtesy of NASA/JPL-Caltech/UCLA.)