AGNs Seen at Different Angles
One type of active galactic nuclei (AGN) — a supermassive black hole that is gobbling up gas and dust — is called a quasar. Quasars got their name because, when first discovered, they were called “quasi-stellar objects” meaning “star-like.” They are very powerful sources of radiation, sometimes having luminosities thousands of times greater than entire galaxies, but when observed optically they appeared to only be distant faint stars or, in some cases, didn’t appear at all. Nowadays we know these objects are actually the nuclei of galaxies with feeding supermassive black holes at their centers. These supermassive black holes swirl the nearby gas and dust into an accretion disk and often emit jets of particles away at nearly the speed of light. If one of these jets happens to be pointing directly at the Earth we call it a blazar.