Sometimes, astronomers get lucky and catch an event they can watch to see how the properties of some of the most massive objects in the universe evolve. That happened in February 2020, when a team of international astronomers led by Dheeraj (DJ) Pasham at MIT found one particular kind of exciting event that helped them track the speed at which a supermassive black hole was spinning for the first time. Dr. Pasham found AT2020ocn, a bright flash …