LIGO and Virgo have observed their largest black hole merger to date, an event called GW190521, in which a final black hole of 142 solar masses was produced. This chart compares the event to others witnessed by LIGO and Virgo and indicates that the remnant of the GW190521 merger falls into a category known as an intermediate-mass black hole – and is the first clear detection of a black hole of this type. Intermediate-mass black holes, which have previously been predicted theoretically, would have masses between those of stellar-mass black holes and the supermassive ones at the hearts of galaxies. Image credit: LIGO/Caltech/MIT/R. Hurt (IPAC)