The dates printed are not always reliable; January and December issues are particularly prone to errors.
In his article "Scientist of the day" for the Linda Hall Library at the University of Missouri, William B Ashworth Jr wrote:
On Valentine's Day, Feb. 14, 1974, so the story goes, Stephen W. Hawking was wheeled into a meeting room at the Rutherford Appleton Laboratory south of Oxford, where they were having a symposium on quantum gravity. Hawking was a member of the Dept. of Applied Mathematics and Theoretical Physics at Cambridge. He was 32 years old. Twelve years earlier, he had been diagnosed with ALS, but the disease was progressing more slowly than predicted, and although he was now confined to a wheelchair, his mind remained fully functional (as it would until his death, 44 years later).
Hawking had been working on black holes for some time, although they were thought to be fairly well understood. A black hole is a singularity of space and time; it has mass, charge, and angular momentum, but no other attributes. The individual features of whatever goes into a black hole, be it a collapsing star or a plethora of kitchen sinks, are wiped out in the black hole. "A black hole has no hair" is the way this was put by the American physicist John Wheeler, who had a way with phrases (he coined the very term black hole in 1967). A black hole is surrounded by an "event horizon" and anything that crosses the event horizon has entered on a one-way street from which there is no return. Nothing, not even light, can escape from a black hole. Or so it was thought.
Hawking decided to apply quantum mechanics to black holes. In the quantum world, funny things can happen. For example, a particle and its antiparticle might spontaneously appear out of nothing, and then disappear; the energy for this is available in the quantum world, provided the time interval is short. But, Hawking wondered, what if a pair of virtual particles were created just outside the event horizon of a black hole? One of the created particles might disappear over the event horizon and would be unable to reunite with its counterpart. The lone survivor would then zip away, carrying energy. To the observer, it would look like the particle had come out of the black hole, and that the black hole was radiating energy. That was the gist of Hawking's paper, which was titled "Particle creation by black holes." Black holes are not necessarily prisons of light; they can leak. In fact, the smaller ones should be able to radiate themselves out of existence.
The reaction that day was memorable, or so it has been said. The chairman of the session, a respected physicist, supposedly declared Hawking's paper to be rubbish. No one believed Hawking's claims. Hawking was threatening to turn the world of black-hole research inside out, and the home team was resisting. So that is the legend of Hawking's Valentine's Day paper. It was told essentially this way by Hawking himself and his first wife Jane in a PBS documentary in 2014, available on YouTube.
