My research interests are focused on supernovae and their use in understanding the physics of explosions. I was a member of the high-z team that co-discovered the acceleration of the expansion of the universe (for which we were all awarded the Gruber prize, more recently the Breakthrough prize and for which Brian and Adam were awarded the Nobel prize for physics) and was a member of the ESSENCE collaboration that continued that work. I have participated in work on beta Pic, comets, brown dwarfs, planetary nebulae etc.