Many efforts have been made to address the paradox. A physicist named Stephen Hawking theorized a solution that, if valid, would reconcile quantum mechanics and the existence of black holes. He posited that black holes only break quantum mechanics at larger masses—that atomic and subatomic particles could be emitted from black holes. These theorized particles are called Hawking radiation. When the Bollard and McTavish departed Earth, Hawking radiation had never actually been observed.”