James Edward Gunn (born October 21, 1938) is the Eugene Higgins Professor of Astronomy at Princeton University.Gunn's early theoretical work in astronomy has helped establish the current understanding of how galaxies form, and the properties of the space between galaxies. He also suggested important observational tests to confirm the presence of dark matter in galaxies, and predicted the existence of a Gunn–Peterson trough in the spectra of distant quasars.He won the Bruce Medal of the Astronomical Society of the Pacific in 2013.