Time dilation and dark matter

 Maybe time dilation causes a change in the perceived expansion rate of matter v empty space. Gravity which accompanies mass also has the effect of slowing down time from the viewpoint of the mass.  

Watching mass and empty space expand (while in a planetary gravity field of the planet),  the empty space would appear to take less time to expand and thus seem like advancing faster?  

 

The expansion rate of the universe would appear to be accelerating

With mass looking  to need more  mass for parity. Thus missing mass would seem to be expected resulting in the invention of dark matter.