It seems to me that the expansion of space is a dynamic event different is principle then the relativistic events which are dealt with by the lorentz transformations. Have there been experiments to determine that it is only space that is expanding and not also a type of ongoing gravitational time dilation to explain the stretching (or redshift) of the wavelength of light? For it would seem to me that if assume a metric of space expands while a metric of time remains the same, then c would increase as the sum of the function delta space/delta time. Also, I know the lorentz transformations can be used for length contraction, but are they bidirectional? Can they be used to imply the observed length expansion of the universe from a particular coordinate system like the earth? Finally, does the Minkowski spacetime invariant provide a preferred worldview for distance and time? Thanks!