WHAT IS A QUASAR? The word quasar stands for quasi-stellar radio source . Quasars got that name because they looked starlike when astronomers first began to notice them in the late 1950s and early 60s. But quasars aren’t stars. Scientists now know they are young galaxies, located at vast distances from us, with their numbers increasing towards the edge of the visible universe. How can they be so far away and yet still visible? The answer is that quasars are extremely bright, up to 1,000 times brighter than our Milky Way galaxy. We know, therefore, that they’re highly active , emitting staggering amounts of radiation across the entire electromagnetic spectrum . Shining so brightly that they eclipse the ancient galaxies that contain them, quasars are distant objects powered by black holes a billion times as massive as our sun. These powerful dynamos have fascinated astronomers since their discovery half a century ago. In the 1930s, Karl Jansky, a physi...