Concept
Virtual Particles
Pairs of particles that flicker in and out of existence in empty space. This quantum restlessness of the vacuum is the key to how Hawking radiation works.
Last updated 23 May 2026 · How we research
Virtual particles are a consequence of one of the strangest features of quantum mechanics: empty space is never truly empty. Because of the uncertainty built into quantum physics, pairs of particles, one matter and one antimatter, are constantly appearing out of the vacuum and almost instantly annihilating each other again. They exist far too briefly to be observed directly, hence "virtual," but their effects are real and measurable.
Why they mattered to Hawking
Virtual particles are the heart of the popular explanation of Hawking radiation. Near a black hole's event horizon, Hawking realised, a pair of virtual particles can be split apart: one falls into the black hole while the other escapes and becomes a real particle, carrying energy away. To balance the books, the black hole loses a tiny amount of mass. Repeated over unimaginable spans of time, this process causes the black hole to slowly shrink and eventually evaporate.
Hawking was always careful to call this a simplified picture rather than the literal mathematics, but it captures the essential and revolutionary point: by taking the quantum restlessness of empty space seriously, he showed that black holes are not entirely black after all.