Vera Rubin. Solver of Problems, Arcane and Mundane

Already in her Ph.D. thesis in 1954, Vera Rubin broke new ground. She demonstrated that galaxies are clumped rather than evenly distributed in space—a surprising and crucial finding, the importance of which was not recognized until many years later. Her exhaustive study of galactic motion produced major discoveries.

Two stand out. The first was that the universe expansion was anisotropic. Before Rubin's measurements, it was assumed that the expansion was the same in all directions.

Rubin showed that this was incorrect: one part of the universe was expanding faster. The second came from her measurements of galactic rotation. Rapidly moving spiral-shaped galaxies should fly apart, but they do not.

The only thing that can hold them together is a large amount of invisible mass, about five to ten times the amount observed in the galaxy itself. This is now called “dark matter” and the conundrum of its presence is one of the major areas of astrophysical research. Rubin was denied permission to work at Mt.

Palomar, with the excuse that there were no facilities for women. She solved the problem by building her own bathroom.