She joined the University of California San Diego (UCSD) in 1962. In the 1960s and 1970s she measured the masses, compositions, and rotation curves of galaxies and performed early spectroscopic studies of quasars. Her discoveries in this area included QSO B1442+101 at a redshift of 3.5, making it the most distant known object at the time, a record which she held from 1974–82. She was a supporter of the steady state theory of cosmology, but her own work on quasars helped to support the alternative Big Bang theory.