NASA's Hubble Space Telescope has photographed a set of wispy, goblin-green objects that are the ephemeral ghosts of quasars that flickered to life and then faded. The ethereal wisps outside the host galaxy are believed to have been illuminated by powerful ultraviolet radiation from a supermassive black hole at the core of the host galaxy. The most active of these galaxy cores are called quasars, where infalling material is heated to a point where a brilliant searchlight shines into deep space. The beam is produced by a disk of glowing, superheated gas encircling the black hole. Read more