http://www.joot.com/dave/writings/articles/entanglement/spookiness.shtml http://www.joot.com/dave/writings/articles/entanglement/quantum-eraser.png 1. a laser fires photons into a Beta Barium Borate (BBO) crystal; 2. the crystal entangles some of the photons; and then 3. entangled photons travel to two different detectors: A and B. Placed between the crystal and detector B is a double-slit, like in the previous experiments. Immediately in front of detector A is a polarizing filter that can be rotated. Each slit is covered by a substance that changes the polarization of a photon. Consequently, the left-hand slit will receive photons with a counter-clockwise polarization, and the right-hand slit will pass photons with a clockwise polarization. ----------------------------------- If we measure polarization at detector A then we have wich-way information and the interference pattern disapear at B, if not we have interference pattern at detector B Now suppose we place a 1 millon km long fiber optic between the BBO crystal and detector A so that each photon will arrive 3 seconds later at detector A. Now we have 3 seconds to decide if we want to get WichWay information or not after the photons hited detector B. So, if i see an interference pattern at B then i set detector A to measure Polarization while the photons are still traveling.. What would be the results of this experiments?