Or is an associate professor of astrophysics at the University of Portsmouth's Institute of Cosmology and Gravitation, an honorary associate professor at University College London (UCL), and a research associate at the American Museum of Natural History. He studies different types of transients—astrophysical phenomena that change on human timescales. He mostly works on supernovae (the explosions of stars) and tidal disruption events (bright flares caused by stars being shredded by supermassive black holes). His books include "Supernova" and "Galaxies" published by MIT Press.
