Imagine an infinite laser beam (at both ends) that passes from the vicinity of an object with some rest mass. The laser beam should bend in a specific way due to gravitational interaction with the object. Now, replace the the laser beam with a rigid material rod of density that corresponds to the the power of the laser so that equivalent energy/mass in the unit volume of the rod is the same as that of laser beam. Furthermore, rod is not straight but it exactly follows the trajectory of the initial laser beam...
My question is that from the view point of the reference object, are there any observable differences between the laser beam and material rod and if there is any, how to justify it? I wonder if "flow of energy" (via the laser beam) makes any difference to the reference object compared to static rod.
Note that an observer in the reference object does not "see" the light beam. No photons from the beam is hitting the object, they simply pass-by. A natural extension of the question is what if the rod is actually a pipe-like construct and the matter inside does flow with some velocity like a laser beam (but with some finite speed of course).
