While black holes were first proposed in the 18th century, they were not seriously proposed until 1916 with Albert Einstein’s General Relativity. The concept of a “black hole” has its roots in the 18th century when John Michell and Pierre-Simon Laplace independently speculated about the existence of “dark stars” — celestial bodies whose gravity is so strong that not even light could escape from them. However, the modern concept of black holes is largely based on the solutions to Albert Einstein’s General Theory of Relativity.

The term “black hole” was not used until much later, but the theoretical foundation was laid in 1916 by Karl Schwarzschild, who found a solution to Einstein’s field equations that described such an object. This solution implied the existence of a singularity, where curvature of spacetime becomes infinite. In 1939, Robert Oppenheimer and others predicted that neutron stars beyond a certain mass would collapse into black holes.