Assuming the setup of Kim, Yoon-Ho; R. Yu, S.P. Kulik, Y.H. Shih, and Marlan Scully (2000). "A Delayed Choice Quantum Eraser". Physical Review Letters 84: 1–5. arXiv:quant-ph/9903047. Bibcode 2000PhRvL..84....1K. doi:10.1103/PhysRevLett.84.1 (See http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser for a free description of their setup) Imagine replacing Detector D1 or D2 (The detectors where information is erased) with a black hole's event horizon (or BSc with an event horizon). If we interpret the results of the Delayed Choice Quantum Eraser Experiment to be an effect of the Advance Wave solution of Maxwell's Equations (See http://en.wikipedia.org/wiki/Wheeler–Feynman_absorber_theory ), will placing a black hole at D1 or D2 prevent the wave from propagating backwards in time, or will it propagate backwards in time from the moment that the two paths are joined at BSc (which I think is the correct answer)? If we replace BSc with the event horizon of a black hole, will the waves be unable to propagate backwards in time, resulting in no interference? [Edit: it has become apparent to me that you need the data at either D1 OR D2 to see an interference pattern at all, since their superposition destroys the pattern. As such, please modify this discussion so as to have the Beam splitter at the event horizon, with D1 going inside the event horizon and D2 remaining outside. You could then deduce which detections at D0 relate to a D1 detection and see if there is an interference pattern) - it therefore appears that my below discussion (now removed) of obtaining information from within the event horizon is thus moot.] Conversely, would this allow us to validate whether a black hole truly does not destroy information (aka it is encoded on its event horizon or sent to another universe)? If we switch perspective to that of the light beam incident onto the event horizon, the light-paths would "join" at the point of the event horizon and erase their path information (unless of course the photons took the other path-determinate route) and not experience any 'spooky effects' from passing through the event horizon. I can't put my finger on it, but I think there are many more insights to be gleaned from this or a similar setup. Can anybody expound on a better setup or the implications of the results?