Quasars are among the brightest objects in the Universe. They are galaxies in which the supermassive black hole is feeding at a tremendous rate: a gargantuan cloud of dust and gas surrounds it, from which the black hole therein is positively guzzling. This process produces vast amounts of blazing light from the frictional and gravitational forces acting on the cloud, causing it to shine. Scientists believe that quasars can form when two galaxies merge, a process that results in a higher concentration of material in the galactic center. And we've seen a lot of evidence of past and ongoing mergers in the more recent Universe, including galactic centers with two or more supermassive black holes on a slow, spiraling collision course.