Joseph Pearce was a Canadian astronomer who became the first director of the Dominion Astrophysical Observatory in Victoria along with John Plaskett. In the 1930s, he published the first detailed analysis of the rotation of the Milky Way Galaxy, demonstrating that the Sun is two thirds from the galactic center and revolves around it once in 220 million years. He also studied radial velocities of O and B stars, catalogued the observable B stars (finding that 40% of them are binary systems), and estimated the temperatures and dimensions of representative giant eclipsing binary stars.