Hello again. In a double slit experiment with electrons, suppose that we have the instrumentation to measure how space-time is curved by these particles. Would it be possible to obtain the electron's position and momentum by measuring the change in the direction of photons that move nearby but without contact? I think that would completely hide the observer, since photons won't strike the electron changing it's momentum. And, photons have no mass and no charge that could alter the electron's behavior in any other way. Unless there is actually some sort of fundamental inter-particle observation, maybe due to forces unification (GUT)?