Black holes with ravenous appetites define Type I active galaxies

Type I and Type II active galaxies do not just appear different — they are, in fact, very different from each other, both structurally and energetically, new research shows. According to the results of a new study, the key factor that distinguishes Type I and Type II galaxies is the rate at which their central black holes — or active galactic nuclei — consume matter and spit out energy.