False-color composite image of infrared data from NASA's Spitzer Space Telescope and radio data from the National Radio Astronomy Observatory's Very Large Array telescope of a quasar (yellow) surrounded by other galaxies (red, blue and green). Many billion times brighter than stars, quasars are thought to be galaxies centered around supermassive black holes. The quasar appears yellow as it emits both infrared and radio light. Quasars are often obscured by a ring, or torus, of gas and dust.