The idea of black or dark stars was interesting, but it was not explored scientifically for more than a century after the notion was proposed in the 1700s. After 1919, when the general theory of relativity was confirmed, scientists started to explore the implications of gravity as the curvature of space by matter. Physicists realized that there could be locations in the universe where space was so severely curved that it would actually be “ripped” or “pinched off.” Anything that fell into that location would not be able to leave. This general relativistic idea of an inescapable spot in space—a hole where not even light could leave—led physicists to coin the term “black hole.”
An artist’s depiction of a black hole. When a star collapses into a black hole, powerful blasts of gamma rays are emitted.