The influence of gravitational binding energy on cosmic expansion dynamics: New perspectives for cosmology

摘要

Confronted with microwave background observations by WMAP and with consternating supernova locations in the magnitude-redshift diagram modern cosmology feels enforced to call for cosmic vacuum energy as a necessary cosmological ingredient. Most often this vacuum energy is associated with Einstein's cosmological constant Λ or with so-called "dark energy". A positive value of Λ describes an inflationary action on cosmic dynamics which in view of recent cosmological data appears as an absolute need. In this article, however, we question the hypothesis of a constant vacuum energy density since not justifiable on physical grounds. Instead we show that gravitational binding energy of cosmic matter, connected with ongoing structure formation during cosmic expansion, acts similar to vacuum energy, since it reduces the effective gravitating proper mass density. Thus one may be encouraged to believe that actions of cosmic vacuum energy and gravitational binding energy concerning their cosmological effects are closely related to each other, perhaps in some respects even have identical phenomenologies. Based on results presented in this article we propose that the generally wanted action of vacuum energy on cosmic spacetime dynamics inevitably leads to a decay of vacuum energy density. Connected with this decay is a decrease of cosmic binding energy and the generation of new effective gravitating mass in the universe. If this all is adequately taken into account by the energy-momentum tensor of the GR field equations, one is then led to non-standard cosmologies which for the first time can guarantee the conservation of the total energy both in static and expanding universes. We describe the structuring of cosmic matter by a change in time of the 2-point correlation-function. We do show here that cosmic structure formation drives accelerated cosmic expansion and feigns the action of vacuum energy density.