Any galaxy that we can see, must have been travelling at less than light speed when the photons that we now see, departed from it. Therefore, the visible rate of galaxy separation is less than light speed. How then, could expansion "stretch" light? Particularly, if it is the expansion of space that is causing galaxies to separate, rather than their own movement, then between any two galaxies there would be pressure in both direction to effect separation. With perhaps hundreds of galaxies between us and the most distant views, light photons would have to overcome the resistance of the space that is pushing in the opposite direction from its own travel. One can understand that if a galaxy was receding from us at a high rate at the moment that the photons left, then the wave-length of the photons could be slightly stretched. On the face of it, in order for space to move galaxies, it must have a high degree of viscosity. This, surely, would have the effect of slowing these hard working photons. Why then are they not compressed by, in the case of the most distant views, several billion years of resistance. And, (perhaps one for the physics guys), why do they weave from side to side, describing a wave motion?