Born in Davenport, England. Studied astronomy at University College London, where she also earned her doctorate. Worked at Yerkes Observatory of the University of Chicago, then at Caltech, where she was often listed as her husband's 'assistant' to obtain observing time. Later — professor at the University of California, San Diego, and director of the Center for Astrophysics and Space Sciences. President of the American Astronomical Society and the American Association for the Advancement of Science. Recipient of the National Medal of Science and the Gold Medal of the Royal Astronomical Society.