Plaskett and Pearce’s Great Discovery

Driven by the desire to understand the structure and shape of the Milky Way galaxy, J.S. Plaskett and J.A. Pearce laboured throughout the late 1920’s and early 1930’s on the study of galactic rotation. Using the efficient Victoria telescope, they discovered that the galaxy rotates once every 240 million years, and that our Solar System lies well away from the galactic centre. They also revise the mass of the Milky Way