The current methods of determining the intrinsic luminosities of supernovas require correcting their apparent luminosities using their redshifts.
These methods are consistent with our current understanding of the redshift effects but this understanding may be put into question if the data collected from the GAIA mission confirms that the motion of stars around in our galaxy does not show the flatness of the angular speed of stars of similar galaxies as determined by their redshifts.
Observational confirmation of the above prediction would support QGD’s explanation of the redshift effects. The relation between redshifts and apparent luminosities following from QGD would allow for more precise determinations of the intrinsic luminosities of supernovas, hence their distances, but only provided that the distances of the reference supernovas are determined through their parallaxes so as to avoid model dependent physical assumptions.
And should QGD’s description of the redshift effect, it would be possible to determine the intrinsic speed of the Earth using supernovas as explained here.