Blazars are the cores of galaxies that contain supermassive black holes that are millions to billions of times the size of the sun. They are some of the most luminous and energetic objects in the universe and emit light across the electromagnetic spectrum.
In 1929, Cuno Hoffmeister discovered a mysterious object, named BL Lacertae. He was not sure how to classify it. Was this object a star? A galaxy? Or something new? Its identity remained a mystery for decades. Nearly 40 years later, this object was discovered to have a radio component. In 1972, this object was discovered to be outside of our galaxy and was very similar to a quasar.
