This stems from the notion that information can not be destroyed, so for example the 2D event horizon of a black hole «records» everything that falls into it. (newscientist.com)
These two objects — which have the biggest apparent event horizons of any black holes that can be viewed from Earth — turn out to be complementary: Sagittarius A * is normally representative of quiet, inactive black holes, whereas M87 typifies the energetic black holes that produce elongated jets of gas and particles. (discovermagazine.com)
Dr Nick Tothill, Senior Lecturer for Computational Imaging, Visual Science & Computational Astrophysics at Western Sydney University, said Hawking had the rare knack of asking unusual but illuminating questions such what really happens at the event horizon of a black hole? (businessinsider.com)