Hawking radiation is a quantum effect of general relativity. English theoretical physicist Stephen Hawking predicted that a black hole ought to emit blackbody radiation. He eventually formulated a quantum-mechanical mechanism of what is now termed Hawking radiation.

In 1958, David Finkelstein, a young postdoctoral fellow at the Stevens Institute of Technology discovered a new reference frame in which to investigate the Schwarzschild space-time geometry surrounding a collapsing star. Expressed in Finkelstein coordinates, the Schwarzschild horizon could be easily seen for what it actually was, a non-singular and well-behaved spherical surface in space-time that acted precisely as a semipermeable membrane. Anything could fall in through the horizon, but nothing could emerge. Inside the horizon the trajectory of any particle, including a photon, traveling initially in any direction, including radially outward, led inexorably towards and always ended at the singularity of infinite curvature.

In 1967, armed with the new understanding...