Black holes: scientific history and classifications

Black holes are celestial regions of space where gravitational pull is so intense that nothing, including light, can escape once it crosses the event horizon. While the concept dates back to the 18th century with John Michell and was later supported by Albert Einstein’s general relativity, the term 'black hole' was officially coined by John Archibald Wheeler in 1967.

Astronomers primarily classify these objects by their mass and rotation. Stellar black holes form from the violent collapse of massive stars following a supernova explosion; these typically range from 3 to 50 times the mass of the Sun. In contrast, supermassive black holes are found at the centers of galaxies and can possess masses equivalent to millions or billions of suns.

A major milestone in astronomy occurred in 2019, when the Event Horizon Telescope (EHT) captured the first image of a black hole in the M87 galaxy, providing visual evidence of their existence and allowing for deeper study of their structure and behavior.