Some tightly-packed globular clusters show signs of unseen black holes affecting the movements of their stars. Astronomers are using the Hubble Space Telescope to look for evidence of such hidden monsters.
Gravitational lensing helps astronomers find one of the most massive black holes yet discovered, a 30-billion solar mass monster at the heart of a remote galaxy.
Astronomers theorize supermassive black holes at the hearts of many if not all large galaxies could host thousands of large planets out to distances up to 10 light years.
Astronomers using X-ray, optical and infrared telescopes have spotted three galaxies – hosting three supermassive black holes – in the process of merging.