Bonjour, We can see light emitted by a star which is effectively behind a gravitational mass. Ok! The light path will curve. Or the light path will be as straight as the space surrounding the gravitational mass. Ok! My question is: When two parallel beams are emitted in the same parallel direction, will these beams will interact? Will they go straight? Will the reach eachother? Will they swirl and stay distant? Will they swirl and reach eachother? For me, on earth! Or for me, on one of the beams! In fact, what will happen to these beams? P.O.