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Speed is a function of distance traveled in unit time, where background time is considered to be invariant. If every mass is a complex of temporal and spatial quantity, then the possibility of 'different' temporal variable for differerent masses is very possible and is, in fact, the blaise explanation of neutrinos and their 'rest mass'. Put another way, if the universe of our experience is a volumetric/present realm, the masses within that realm may have present, past, or future temporal orientation, combined with linear, planar, and/or volumetric spatial orientation.
Taking a thought excursion, if one could 'view' the spacetime continuum in which our world exists, from outside that realm, what would be 'observed' would be a volumetric/past-->future realm, in which exist linear, planar, and volumetric spatial phenomena ... so, why not past, present and future temporal phenomena, also, within the realm 'observed'?