Suddenly Bright Stars is a term used to describe two types of astronomical phenomena: Novas and Novae. Novas are stars that suddenly become much brighter, while Novae are stars that slowly fade in brightness over time. Both of these events are caused by the same process, which is the sudden release of energy from a star's surface. This energy can be released due to a variety of causes, such as a stellar explosion or a collision with another star.