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First observational assessment of cosmic backreaction over an extended redshift range

S. M. Koksbang*

  • *Contact author: koksbang@cp3.sdu.dk
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Phys. Rev. D 114, 043508 – Published 7 August, 2026

DOI: https://doi.org/10.1103/5l42-bjyv

Abstract

In the recent preprint by Heinesen and Clifton [arXiv:2604.07244v1], the authors introduce a novel combination of redshift, distance, and expansion rate observables for constraining cosmic backreaction observationally. The current work presents a first application of the method, in principle yielding the first direct constraints on the total cosmic backreaction in our Universe over a significant redshift range. However, we find that current data are not yet sufficient to place tight constraints on backreaction. Thus, neither vanishing nor significant backreaction can be ruled out with the presented constraints. Nonetheless, the results suggest that forthcoming survey data will enable enlightening constraints on cosmic backreaction using this method.

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Outline

Information

Phys. Rev. D 114, 043508– Published 7 August, 2026
  • Received 17 April 2026
  • Accepted 30 June 2026
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