NASA’s Fermi Gamma-ray Space Telescope has revealed a violent high-energy universe full of stellar explosions, black hole jets, and pulsing stars. These cosmic objects are often faint when observed with visible light, but glow bright with gamma rays. Dr. Romani will describe the quest to discover the true nature of the most puzzling of these gamma-ray sources. Several turn out to be a kind of star corpse called a ‘black widow’ pulsar. When a massive star dies, it leaves a collapsed remnant called a neutron star. When such a star corpse has a companion star, it can be reanimated by material from the companion. Ironically, the revived corpse then begins to vaporize its mate. Dr. Romani will discuss his group’s discovery that these black widows may be the heaviest neutron stars known, on the edge of final collapse to black holes.