In a 1974 paper, Stephen Hawking proposed that black holes are not entirely black but emit thermal radiation. This process causes them to lose mass and eventually evaporate. The theory suggests that while black holes with large masses, such as those comparable to the Sun, have negligible emission rates, smaller primordial black holes could have already vanished.
Hawking's model indicates that the temperature of a black hole is inversely proportional to its mass. As a black hole loses mass through radiation, its temperature increases, leading to a faster rate of emission. This positive feedback loop accelerates until the final stages of evaporation, resulting in a high-energy explosion.
For a black hole with a mass of 10^15 grams, the temperature reaches approximately 10^12 Kelvin. In its final 0.1 seconds, such a black hole would release energy equivalent to about 1 million 1-megaton hydrogen bombs. This theoretical framework was one of the first attempts to apply quantum mechanics to objects described by Einstein's general relativity.
The research highlights that quantum effects, though locally small, can accumulate over the lifetime of the universe. By integrating the mass loss rate, Hawking calculated that the lifetime of a black hole is proportional to the cube of its mass. This challenges the previous scientific consensus that nothing could escape the gravitational pull of a black hole.
