if they have no way of measuring the movement separately, its sounds like an opinion. tell me how is it that our galaxy and Andromeda's are approaching each other unless there is a contraction of space, which has all but been ruled out, and there is no movement. I forget which two galaxies it is, but i remember seeing pictures of two galaxies that are said to be moving though each other again and again, and will one day become one. how is that possible if there is no movement.
another point i thought of after a good bit of time passed. you treat the theory of expanding universe as though it were law. It not a law, only a theory. that is something that explains all the known facts. in fact there are several theories that fit all known fact. here are some I've heard of. i don't know the name of some of them so if any one does, please let me know.
one theory stated that the big bang was not like a ball, but in fact was like a series of hollow spheres, each inside the next. as the subphotonic stuff coalesced into first photon and then matter, they were at different distances, thus the farthest spheres were not affected as much by the gravity created by the inner materials and thus were not slowed down as much. in this theory, all the galaxies are moving in the directions that they were first moved in, or lasted effected by other galaxies.
another theory is that there is a dark matter, one that we cant see because its is in one of the dimensions other than the 4 we can detect (its speculated that there are 11 dimensions). since to this material gravity is a "pushing force" rather than a "pulling force" (for lack of better terms), it exist between galaxies rather than in them. it is pushed away by the galaxies gravity and pushes them. this causes the farthest galaxies (which have nothing on the other side to push them back) to move faster than the ones inside which are being pushed back by the dark matter, thus don't move as fast.
then there is the brane theory. once again it involves material that is in one of the 7 dimensions we cant explore. According to this there was not exactly a big bang, more of like a cymbal crashing together and producing the materials of our universe. as these cymbals expanded the material coalesced at different points and different speeds depending on the speed of the cymbal at that time. according to this theory, eventually the matterial of our universe will entrophy into nothingness, at which point another crash will occur to produce a new universe.
the point of all of this is that there are other theories that can explain all of this without trying to create something like some unknown force causing the universe to expand. the expanding universe maybe the most accepted, but i seem to recall someone saying something about the fact that 'just because x will explain something, does not mean that x is correct.'
