Artist's illustration of a quasar (IMAGE) University of Arizona Caption Quasars — shown here in an artist's illustration— are some of the brightest objects in the universe. The energy released by the quasar's supermassive black hole as it devours mass from its surroundings is widely considered to be the main driver in limiting the growth of massive galaxies. Credit Space Telescope Science Institute Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.