Cosmic Acceleration without Dark Energy: Projection, Averaging, and Effective Descriptions in Cosmology
Year: 2026
Type: preprint
Abstract: The accelerated expansion of the universe is a well-established observational result, mostprominently inferred from distance–redshift relations of Type Ia supernovae. In standardcosmology, this behavior is commonly attributed to a cosmological constant or an exotic darkenergy component. However, such an interpretation exceeds what is directly supported byobservation: acceleration is not measured as a fundamental physical entity, but reconstructedwithin a specific representational framework.In this paper, we argue that the phenomenology commonly ascribed to dark energy canbe consistently understood as an effective projection phenomenon, without postulating a newfundamental energy component. We distinguish carefully between observational signatures,their reconstruction within homogeneous cosmological models, and the ontological status ofthe terms introduced to account for them.We analyze three mathematically well-established mechanisms by which acceleration-likebehavior arises generically in reduced descriptions: (i) averaging and backreaction effectsin the transition from inhomogeneous dynamics to Friedmann–Robertson–Walker models,(ii) projection effects inherent in the reconstruction of cosmological expansion histories fromobservational data, and (iii) effective terms induced when a more comprehensive dynamicaldescription is projected onto spacetime-based field equations. In each case, accelerationemerges as a consequence of non-commutativity between reduction and evolution, rather thanas evidence for a new fundamental source.We synthesize these mechanisms into a unified interpretive framework in which thecosmological constant appears as a bookkeeping term encoding projection-induced effects.This perspective preserves the empirical success of standard cosmology while relaxing itsontological commitments, and clarifies why cosmic acceleration does not, by itself, requirethe existence of dark energy as a fundamental physical entity.
Author: Axelkrans, Erik
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7201875503