Stephen Hawking’s conception of transmissions from a black hole involves particle-antiparticle pairs that are created near the event horizon (the point of no return near a black hole, beyond which matter and energy are unable to escape). When this spontaneous creation occurs, as it does everywhere in space, the particle and antiparticle travel in opposite directions. If one member of the pair travels into the event horizon (never to be seen again), the other will fly away from the black hole.
