Hypermassive black holes (or HMBH) were the largest black holes in the universe. Hypermassive black holes were defined as having a mass in excess of a billion yellow stars, thousands of times heavier than the galactic center. Occasionally they were found in the centers of large, elliptical galaxies. Galaxies containing these black holes often experienced quasars.
Formation and mass[]
HMBHs were formed in the same way as other black holes above stellar mass, such as IMBH and SMBH, but on a much larger scale. They were formed in multiple galaxy mergers, when many thousands of Supermassive black holes merged.
These mergers often blew entire galaxies apart, and scattered millions of star systems across the universe. Some cosmologists believed that the creation of HMBH's was responsible for wondering star systems like Sebbadon, as well as solitary supermassive black holes.
Hypermassive black holes were large enough to pull almost anything into their grip. They had event horizons spanning thousands of light years.
Some scientists believed that these black holes would eventually cause the death of the universe, becoming so massive as to pull the entire fabric of space inside themselves as well as everything else in the universe.