Originally, researchers believed absolutely nothing could escape a black hole, meaning everything that passes its event horizon would be ripped apart, devoured and never seen gain, while the black hole would grow ever larger. But in the 1970s, Hawking developed the concept of Hawking radiation, which would mean that instead of expanding over time, black holes might eventually dissolve. The idea relies upon two weird phenomena: quantum fluctuation, a bizarre ability of subatomic particles to (very rarely) pop spontaneously into existence, and quantum tunneling, which allows particles to essentially burrow through impenetrable barriers. Sometimes, for instance, matter and antimatter particles will suddenly emerge from nothing and then annihilate each other, and if that happens at the boundary of the black hole, it’s possible for a particle to pop into existence on the outside edge of the black hole and zoom out into space, so its antimatter partner doesn’t have a chance to annihilate it, and instead gets sucked into the black holes center. Over time, this would mean the black hole is leaking and would eventually decrease in size. In order to escape, however, particles would need to be extremely big — on the order of the black hole in size, which would mean only very low energy light could leak out of the most massive black holes. So far, no one has directly measured Hawking radiation but most physicists are convinced it exists, Live Science previously reported.