Dr. Rubin is a cosmologist, mostly using type Ia supernovae. When well measured, these supernovae can be used as “standard candles,” meaning their apparent brightness gives their distances. These distances help us measure both the expansion history of the universe and small deviations from that expansion history (peculiar velocities and large-scale structure). The objects themselves are also astrophysically important. Dr. Rubin’s interests span survey planning and optimization (for example, for the Roman Space Telescope SN program), observing (mostly on UH telescopes and the Hubble Space Telescope), data reduction and calibration, and cosmological parameter inference.