Black holes are among the strangest things in the universe. They are massive objects – collections of mass – with gravity so strong that nothing can escape, not even light. The most common types of black holes are the stellar-mass and supermassive black holes. Stellar-mass black holes are created when massive stars explode, leaving behind a black hole with the mass of just a few suns. Supermassive black holes exist in the hearts of galaxies and usually contain the mass equivalent of millions of suns.

Famous Black Holes

Cygnus X-1: a stellar-mass black hole and x-ray source that lies some 6,500 light-years away. It is a binary system that contains a blue supergiant variable star and the x-ray source thought to be the black hole.

Sagittarius A*: the supermassive black hole at the heart of the Milky Way Galaxy. It lies in the direction of the constellation Sagittarius. This black hole contains the mass of about 4 million suns.

M87: this elliptical galaxy has a 3.5 billion solar-mass black hole at its heart. The black hole is surrounded by a disk of superheated material and has a jet of superheated material streaming away from the black hole that extends across 5,000 light-years from the galaxy’s core.

Centaurus A: this galaxy, which lies in the direction of the constellation Centaurus, is a giant spiral galaxy with an incredibly active nucleus. It contains a 55 million solar-mass black hole at its heart, with two jets of material that stream away from the galaxy at about half the speed of light across a million light-years of space.

Facts about Black Holes