On the Interpretation of Cosmic Acceleration

The traditional way to define cosmic acceleration, denoted \ (q \), relies on a comoving frame of reference within a 3D space-like coordinate system. This is the acceleration of the background metric in a particular frame rather than the actual acceleration between different observers on time-like geodesics. This traditional choice obscures the true physical processes, much like the Earth-centered model historically obscured the understanding of gravitational forces before the heliocentric shift. In this study, we introduce \ (qE \), a new metric defined by distances between causal events (i. e. acceleration between observes) in 4D null space. We compare \ (qE \) with \ (q \) using observational data from supernovae (SN) and radial clustering of galaxies and quasars (BAO). Our results show that \ (qE \) offers a closer alignment with this data. Our analysis reveals that cosmic expansion, when viewed from the rest frame, is actually decelerating, confined by dynamics inside an Event Horizon, similar to conditions within a Black Hole interior. This indicates that \ (\) acts not as an agent of new dark energy or as a modification of gravity, but as a boundary term exerting an attractive force similar to a rubber band, which resists further expansion and prevents horizon crossing of events. We show how this interpretation of cosmic expansion as deceleration in the rest frame challenges conventional cosmological models and suggests that a reevaluation of these models is necessary.