Hawking radiation causes black holes to eventually evaporate. This is because particle pairs are spontaneously created near the event horizon (the position of the last ray of light that can escape the black hole's gravitational pull). A particle and its antiparticle are created for a brief moment and disappear immediately afterward. But sometimes a particle falls into the black hole, allowing the other particle to escape: This is Hawking radiation. According to Stephen Hawking, this would ultimately mean that no black holes would remain in the universe.