4 ms·

You'd need the box to block gravity, and have a way of letting only your single photon pass through the box to interact with the system. Otherwise the star's po

You'd need the box to block gravity, and have a way of letting only your single photon pass through the box to interact with the system. Otherwise the star's position would have already been measured by past light being deflected. The two photon paths would not interfere with each other. The injected photon's resulting position is entangled with the star's position, meaning you could tell which leg of the interferometer the photon had taken by later opening the star box, so it acts analogous to putting a detector on one arm of an interferometer and you get no self-interference.

lisper 11y ago
> Otherwise the star's position would have already been measured by past light being deflected Well, this is the interesting question, isn't it. We don't actually know what happens to spacetime when you get a macroscopic divergence like this because we only have access to this one universe, and no good theory of quantum gravity (yet). It's possible (for example) that there is only one spacetime for the wavefunction, and that what is currently called "dark matter" is really the result of macroscopic superpositions of states.