Quasar candidates. Image from the all-sky survey from NASA's Wide-field Infrared Survey Explorer (WISE), showing a collection of quasar candidates. NASA's Wide-field Infrared Survey Explorer (WISE) has identified millions of quasar candidates. Quasars are supermassive black holes with masses millions to billions times greater than our sun. The black holes feed off surrounding gas and dust, pulling the material onto them. As the material falls in on the black hole, it becomes extremely hot and extremely bright. This image zooms in on one small region of the WISE sky, covering an area about three times larger than the moon. The WISE quasar candidates are highlighted with yellow circles.