Hello excuse my bad english u take two large masses for example two black holes. Now we imagine we could bring the two masses very near together. And now we send an laserstream(lightstream) exactly in the middle of the distance between the 2 masses. The question is what happens to the stream? On left and right side is a very huge gravity-potential. What does the light here? Bcause if the photon is an particle, such an huge gravity must have any effects on this particle isnt it? Or if light is in this case wave what happens then? Einstein says the light follows the room-crookedness (raumkrümmung) this would mean that nothing happens? Is someone there how knows mor about this?