GRAVISTAR
A gravastar is an extremely dense, cold, dark, thick-shelled object that contains springy, oddly-behaving space inside it. A gravistar is the remnant of a dying star that has imploded; it has many similarities to a black hole, but emits far brighter X-rays than a black hole. Gravistars were theorized to exist in 2002 by Emil Mottola of Los Alamos National Laboratory, New Mexico, and Pawel Mazur of the University of South Carolina, Columbia. The existence of gravistars is not universally accepted.