What is Hawking radiation?

In 1974, Hawking proposed that black holes are not completely black — they emit radiation due to quantum effects near the event horizon. Classical physics said nothing escapes a black hole. Hawking showed that quantum mechanics changes this at the boundary. Virtual particle pairs constantly pop in and out of existence near the event horizon; sometimes one falls in and one escapes. From outside, this looks like the black hole is radiating energy.

Why is this discovery so significant?

It was the first theoretical bridge between quantum mechanics and general relativity — two theories that otherwise don't play well together. Hawking radiation predicted something both theories had to account for: information and energy loss at the black hole boundary. This led to the "information paradox" — one of the most productive unsolved problems in modern physics.

Does Hawking radiation mean black holes eventually disappear?

Yes, theoretically. If a black hole radiates energy and nothing replenishes it, it should slowly shrink and eventually evaporate. The timescale is incomprehensibly long for stellar-mass black holes — longer than the current age of the universe many times over. But for tiny primordial black holes, Hawking evaporation could be detectable.

Has Hawking radiation ever been observed?

Not directly in a real black hole — the radiation from astrophysical black holes is too faint to detect with current technology. But laboratory analogues (using phonons in Bose-Einstein condensates) have shown effects consistent with the theory.

What did this discovery mean for Hawking personally?

It made his career. A Brief History of Time built public understanding on this and other concepts. It positioned him not just as a physicist but as the person who showed black holes had lifetimes — that even the most extreme objects in the universe obey physics that human minds can grasp.