These objects possess an ergosphere within which occurs the Lense-Thirring effect.
These objects possess an ergosphere within which occurs the Lense-Thirring effect. The Reissner-Nordstrom metric is used to describe non-rotating ones that possess electrical charge. Mass, electric charge, and angular momentum are the only properties of these objects according to the No Hair Theorem, and energy may be extracted from these via the Penrose Process. Pair production in one of these may result in Hawking Radiation if it occurs near the event horizon. Formed when a supernova remnant exceeds the Oppenheimer-Volkoff limit, this is, for 10 points, what type of collapsed star that is named for its ability to trap light? 
These objects possess an ergosphere within which occurs the Lense-Thirring effect.
black hole