Black holes have long served as fodder for science fiction — and for good reason. These unimaginably dense objects contain so much matter trapped in such a small volume that their gravity prevents even light from escaping their surfaces.
Although the first prediction of a black hole was made nearly 250 years ago by the English philosopher and clergyman John Michell, the first black hole candidate, Cygnus X-1, wasn’t discovered until 1971. Since then, astronomers have tirelessly chipped away at countless questions related to these once-mythical beasts. But one of the most basic and enduring questions remains: Do they come in all sizes?
