Black holes are some of the most fascinating and mysterious objects in the universe. These regions of space are so dense that their gravitational pull is strong enough to prevent anything, even light, from escaping. The term "black hole" was first coined by physicist John Archibald Wheeler in 1967, though the concept dates back to the early 20th century, when Albert Einstein's theory of general relativity suggested that objects could collapse into singularities, points of infinite density. A black hole is the result of such a collapse, where a star's mass is concentrated in an infinitely small space.

At the heart of a black hole is the singularity, surrounded by a boundary known as the event horizon. The event horizon marks the point beyond which nothing can escape the black hole's gravitational influence. This includes not only matter but also radiation, which is why black holes appear "black." Despite their invisibility, black holes are detectable through their interactions with surrounding matter, such as the accretion of gas and dust that emits detectable radiation.

The formation of a black hole typically begins when a massive star exhausts its nuclear fuel. Without the outward pressure from nuclear fusion to counterbalance gravity, the core of the star collapses under its own weight. If the star is massive enough, this collapse can continue, compressing the core into a singularity. The outer layers of the star are expelled in a supernova explosion, and the remaining core becomes a black hole.